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Shimonty A, Pin F, Prideaux M, Peng G, Huot J, Kim H, Rosen CJ, Spiegelman BM, Bonewald LF. Deletion of FNDC5/irisin modifies murine osteocyte function in a sex-specific manner. eLife 2024; 12:RP92263. [PMID: 38661340 PMCID: PMC11045224 DOI: 10.7554/elife.92263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
Irisin, released from exercised muscle, has been shown to have beneficial effects on numerous tissues but its effects on bone are unclear. We found significant sex and genotype differences in bone from wildtype (WT) mice compared to mice lacking Fndc5 (knockout [KO]), with and without calcium deficiency. Despite their bone being indistinguishable from WT females, KO female mice were partially protected from osteocytic osteolysis and osteoclastic bone resorption when allowed to lactate or when placed on a low-calcium diet. Male KO mice have more but weaker bone compared to WT males, and when challenged with a low-calcium diet lost more bone than WT males. To begin to understand responsible molecular mechanisms, osteocyte transcriptomics was performed. Osteocytes from WT females had greater expression of genes associated with osteocytic osteolysis and osteoclastic bone resorption compared to WT males which had greater expression of genes associated with steroid and fatty acid metabolism. Few differences were observed between female KO and WT osteocytes, but with a low-calcium diet, the KO females had lower expression of genes responsible for osteocytic osteolysis and osteoclastic resorption than the WT females. Male KO osteocytes had lower expression of genes associated with steroid and fatty acid metabolism, but higher expression of genes associated with bone resorption compared to male WT. In conclusion, irisin plays a critical role in the development of the male but not the female skeleton and protects male but not female bone from calcium deficiency. We propose irisin ensures the survival of offspring by targeting the osteocyte to provide calcium in lactating females, a novel function for this myokine.
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Affiliation(s)
| | | | | | - Gang Peng
- Indiana UniversityIndianapolisUnited States
| | | | - Hyeonwoo Kim
- Korea Advanced Institute of Science and TechnologyDaejonRepublic of Korea
| | | | | | - Lynda F Bonewald
- Indiana UniversityIndianapolisUnited States
- Indiana Center for Musculoskeletal HealthIndianapolisUnited States
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Shimonty A, Pin F, Prideaux M, Peng G, Huot JR, Kim H, Rosen CJ, Spiegelman BM, Bonewald LF. Deletion of FNDC5/Irisin modifies murine osteocyte function in a sex-specific manner. bioRxiv 2024:2023.11.06.565774. [PMID: 37986762 PMCID: PMC10659274 DOI: 10.1101/2023.11.06.565774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Irisin, released from exercised muscle, has been shown to have beneficial effects on numerous tissues but its effects on bone are unclear. We found significant sex and genotype differences in bone from wildtype (WT) mice compared to mice lacking Fndc5 (KO), with and without calcium deficiency. Despite their bone being indistinguishable from WT females, KO female mice were partially protected from osteocytic osteolysis and osteoclastic bone resorption when allowed to lactate or when placed on a low-calcium diet. Male KO mice have more but weaker bone compared to WT males, and when challenged with a low-calcium diet lost more bone than WT males. To begin to understand responsible molecular mechanisms, osteocyte transcriptomics was performed. Osteocytes from WT females had greater expression of genes associated with osteocytic osteolysis and osteoclastic bone resorption compared to WT males which had greater expression of genes associated with steroid and fatty acid metabolism. Few differences were observed between female KO and WT osteocytes, but with a low calcium diet, the KO females had lower expression of genes responsible for osteocytic osteolysis and osteoclastic resorption than the WT females. Male KO osteocytes had lower expression of genes associated with steroid and fatty acid metabolism, but higher expression of genes associated with bone resorption compared to male WT. In conclusion, irisin plays a critical role in the development of the male but not the female skeleton and protects male but not female bone from calcium deficiency. We propose irisin ensures the survival of offspring by targeting the osteocyte to provide calcium in lactating females, a novel function for this myokine.
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Affiliation(s)
- Anika Shimonty
- Indiana Center for Musculoskeletal Health, School of Medicine, Indiana University, IN, 46202, Indianapolis
| | - Fabrizio Pin
- Indiana Center for Musculoskeletal Health, Department of Anatomy, School of Medicine, Indiana University, IN, 46202, Indianapolis
| | - Matt Prideaux
- Indiana Center for Musculoskeletal Health, Department of Anatomy, School of Medicine, Indiana University, IN, 46202, Indianapolis
| | - Gang Peng
- Indiana Center for Musculoskeletal Health, Department of Medicine and Molecular Genetics, School of Medicine, Indiana University, IN, 46202, Indianapolis
| | - Joshua R Huot
- Indiana Center for Musculoskeletal Health, Department of Anatomy, School of Medicine, Indiana University, IN, 46202, Indianapolis
| | - Hyeonwoo Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Clifford J Rosen
- Maine Medical Center Research Institute, ME, 04074, Scarborough, USA
| | - Bruce M Spiegelman
- Department of Cancer Biology, Dana Farber Cancer Institute and Department of Cell Biology, Harvard University Medical School, MA, 02115, Boston, USA
| | - Lynda F Bonewald
- Department of Anatomy, Cell Biology and Physiology, Orthopaedic Surgery, School of Medicine, Indiana Center for Musculoskeletal Health, Indiana Center for Musculoskeletal Health, Indiana University, IN, 46202, Indianapolis
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Wang H, Li T, Jiang Y, Chen S, Zou S, Bonewald LF, Duan P. Force-Loaded Cementocytes Regulate Osteoclastogenesis via S1P/S1PR1/Rac1 Axis. J Dent Res 2023; 102:1376-1386. [PMID: 37735908 DOI: 10.1177/00220345231195765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/23/2023] Open
Abstract
Orthodontically induced inflammatory root resorption (OIIRR) is the major iatrogenic complication of orthodontic treatment, seriously endangering tooth longevity and impairing masticatory function. Osteoclasts are thought to be the primary effector cells that initiate the pathological process of OIIRR; however, the cellular and molecular mechanisms responsible for OIIRR remain unclear. Our previous studies revealed that cementocytes, the major mechanically responsive cells in cementum, respond to compressive stress to activate and influence osteoclasts locally. For this study, we hypothesized that the sphingosine-1-phosphate (S1P) signaling pathway, a key mechanotransduction pathway in cementocytes, may regulate osteoclasts under the different magnitudes of either physiologic compressive stress that causes tooth movement or pathologic stress that causes OIIRR. Here, we show a biphasic effect of higher compression force stimulating the synthesis and secretion of S1P, whereas lower compression force reduced signaling in IDG-CM6 cementocytes. Using conditioned media from force-loaded cementocytes, we verified the cell-to-cell communication between cementocytes and osteoclasts and show that selective knockdown of S1PR1 and Rac1 plays a role in cementocyte-driven osteoclastogenesis via the S1P/S1PR1/Rac1 axis. Most importantly, the use of inhibitors of this axis reduced or prevented the pathological process of OIIRR. The intercellular communication mechanisms between cementocytes and osteoclasts may serve as a promising therapeutic target for OIIRR.
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Affiliation(s)
- H Wang
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases;Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - T Li
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases;Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
- Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; Shanghai Research Institute of Stomatology
| | - Y Jiang
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases;Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - S Chen
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases;Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - S Zou
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases;Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - L F Bonewald
- Departments of Anatomy, Cell Biology & Physiology and Orthopaedic Surgery, Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA
| | - P Duan
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases;Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
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Lara-Castillo N, Masunaga J, Brotto L, Vallejo JA, Javid K, Wacker MJ, Brotto M, Bonewald LF, Johnson ML. Muscle secreted factors enhance activation of the PI3K/Akt and β-catenin pathways in murine osteocytes. Bone 2023; 174:116833. [PMID: 37385426 PMCID: PMC10926931 DOI: 10.1016/j.bone.2023.116833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 06/19/2023] [Accepted: 06/25/2023] [Indexed: 07/01/2023]
Abstract
Skeletal muscle and bone interact at the level of mechanical loading through the application of force by muscles to the skeleton and more recently focus has been placed on molecular/biochemical coupling of these two tissues. We sought to determine if muscle and muscle-derived factors were essential to the osteocyte response to loading. Botox® induced muscle paralysis was used to investigate the role of muscle contraction during in vivo tibia compression loading. 5-6 month-old female TOPGAL mice had their right hindlimb muscles surrounding the tibia injected with either BOTOX® or saline. At four days post injections when muscle paralysis peaked, the right tibia was subjected to a single session of in vivo compression loading at ∼2600 με. At 24 h post-load we observed a 2.5-fold increase in β-catenin signaling in osteocytes in the tibias of the saline injected mice, whereas loading of tibias from Botox® injected mice failed to active β-catenin signaling in osteocytes. This suggests that active muscle contraction produces a factor(s) that is necessary for or conditions the osteocyte's ability to respond to load. To further investigate the role of muscle derived factors, MLO-Y4 osteocyte-like cells and a luciferase based β-catenin reporter (TOPflash-MLO-Y4) cell line we developed were treated with conditioned media (CM) from C2C12 myoblasts (MB) and myotubes (MT) and ex vivo contracted Extensor Digitorum Longus (EDL) and Soleus (Sol) muscles under static or loading conditions using fluid flow shear stress (FFSS). 10 % C2C12 myotube CM, but not myoblast or NIH3T3 fibroblast cells CM, induced a rapid activation of the Akt signaling pathway, peaking at 15 min and returning to baseline by 1-2 h under static conditions. FFSS applied to MLO-Y4 cells for 2 h in the presence of 10 % MT-CM resulted in a 6-8 fold increase in pAkt compared to a 3-4 fold increase under control or when exposed to 10 % MB-CM. A similar response was observed in the presence of 10 % EDL-CM, but not in the presence of 10 % Sol-CM. TOPflash-MLO-Y4 cells were treated with 10 ng/ml Wnt3a in the presence or absence of MT-CM. While MT-CM resulted in a 2-fold activation and Wnt3a produced a 10-fold activation, the combination of MT-CM + Wnt3a resulted in a 25-fold activation of β-catenin signaling, implying a synergistic effect of factors in MT-CM with Wnt3a. These data provide clear evidence that specific muscles and myotubes produce factors that alter important signaling pathways involved in the response of osteocytes to mechanical load. These data strongly suggest that beyond mechanical loading there is a molecular coupling of muscle and bone.
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Affiliation(s)
- N Lara-Castillo
- Department of Oral and Craniofacial Sciences, UMKC School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, United States of America.
| | - J Masunaga
- Department of Oral and Craniofacial Sciences, UMKC School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, United States of America
| | - L Brotto
- Bone-Muscle Research Center, College of Nursing and Health Innovation, University of Texas at Arlington, 411 S. Nedderman Dr, Arlington, TX 76019, United States of America
| | - J A Vallejo
- Department of Oral and Craniofacial Sciences, UMKC School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, United States of America; Department of Biomedical Sciences, UMKC School of Medicine, 2411 Holmes, Kansas City, MO 64108, United States of America
| | - K Javid
- Department of Oral and Craniofacial Sciences, UMKC School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, United States of America
| | - M J Wacker
- Department of Biomedical Sciences, UMKC School of Medicine, 2411 Holmes, Kansas City, MO 64108, United States of America
| | - M Brotto
- Department of Biomedical Sciences, UMKC School of Medicine, 2411 Holmes, Kansas City, MO 64108, United States of America
| | - L F Bonewald
- Department of Oral and Craniofacial Sciences, UMKC School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, United States of America; Indiana Center for Musculoskeletal Health, Barnhill Drive, Indianapolis, IN 46202, United States of America
| | - M L Johnson
- Department of Oral and Craniofacial Sciences, UMKC School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, United States of America
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Shimonty A, Bonewald LF, Huot JR. Metabolic Health and Disease: A Role of Osteokines? Calcif Tissue Int 2023; 113:21-38. [PMID: 37193929 DOI: 10.1007/s00223-023-01093-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 05/01/2023] [Indexed: 05/18/2023]
Abstract
Maintenance of skeletal health is tightly regulated by osteocytes, osteoblasts, and osteoclasts via coordinated secretion of bone-derived factors, termed osteokines. Disruption of this coordinated process due to aging and metabolic disease promotes loss of bone mass and increased risk of fracture. Indeed, growing evidence demonstrates that metabolic diseases, including type 2 diabetes, liver disease and cancer are accompanied by bone loss and altered osteokine levels. With the persistent prevalence of cancer and the growing epidemic of metabolic disorders, investigations into the role of inter-tissue communication during disease progression are on the rise. While osteokines are imperative for bone homeostasis, work from us and others have identified that osteokines possess endocrine functions, exerting effects on distant tissues including skeletal muscle and liver. In this review we first discuss the prevalence of bone loss and osteokine alterations in patients with type 2 diabetes, non-alcoholic fatty liver disease, non-alcoholic steatohepatitis, cirrhosis, and cancer. We then discuss the effects of osteokines in mediating skeletal muscle and liver homeostasis, including RANKL, sclerostin, osteocalcin, FGF23, PGE2, TGF-β, BMPs, IGF-1 and PTHrP. To better understand how inter-tissue communication contributes to disease progression, it is essential that we include the bone secretome and the systemic roles of osteokines.
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Affiliation(s)
- Anika Shimonty
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Lynda F Bonewald
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA
- Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Joshua R Huot
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA.
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA.
- Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, USA.
- Department of Kinesiology, School of Health and Human Sciences, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA.
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6
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Prideaux M, Smargiassi A, Peng G, Brotto M, Robling AG, Bonewald LF. L-BAIBA Synergizes with Sub-Optimal Mechanical Loading to Promote New Bone Formation. JBMR Plus 2023; 7:e10746. [PMID: 37283651 PMCID: PMC10241089 DOI: 10.1002/jbm4.10746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/21/2023] [Accepted: 03/28/2023] [Indexed: 06/08/2023] Open
Abstract
The L-enantiomer of β-aminoisobutyric acid (BAIBA) is secreted by contracted muscle in mice, and exercise increases serum levels in humans. In mice, L-BAIBA reduces bone loss with unloading, but whether it can have a positive effect with loading is unknown. Since synergism can be more easily observed with sub-optimal amounts of factors/stimulation, we sought to determine whether L-BAIBA could potentiate the effects of sub-optimal loading to enhance bone formation. L-BAIBA was provided in drinking water to C57Bl/6 male mice subjected to either 7 N or 8.25 N of sub-optimal unilateral tibial loading for 2 weeks. The combination of 8.25 N and L-BAIBA significantly increased the periosteal mineral apposition rate and bone formation rate compared to loading alone or BAIBA alone. Though L-BAIBA alone had no effect on bone formation, grip strength was increased, suggesting a positive effect on muscle function. Gene expression analysis of the osteocyte-enriched bone showed that the combination of L-BAIBA and 8.25 N induced the expression of loading-responsive genes such as Wnt1, Wnt10b, and the TGFb and BMP signaling pathways. One dramatic change was the downregulation of histone genes in response to sub-optimal loading and/or L-BAIBA. To determine early gene expression, the osteocyte fraction was harvested within 24 hours of loading. A dramatic effect was observed with L-BAIBA and 8.25 N loading as genes were enriched for pathways regulating the extracellular matrix (Chad, Acan, Col9a2), ion channel activity (Scn4b, Scn7a, Cacna1i), and lipid metabolism (Plin1, Plin4, Cidec). Few changes in gene expression were observed with sub-optimal loading or L-BAIBA alone after 24 hours. These results suggest that these signaling pathways are responsible for the synergistic effects between L-BAIBA and sub-optimal loading. Showing that a small muscle factor can enhance the effects of sub-optimal loading of bone may be of relevance for individuals unable to benefit from optimal exercise. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Matt Prideaux
- Indiana Center for Musculoskeletal Health, Department of Anatomy, Cell Biology and Physiology, School of MedicineIndiana UniversityIndianapolisINUSA
| | - Alberto Smargiassi
- Indiana Center for Musculoskeletal Health, Department of Anatomy, Cell Biology and Physiology, School of MedicineIndiana UniversityIndianapolisINUSA
| | - Gang Peng
- Indiana Center for Musculoskeletal Health, Department of Medicine and Molecular Genetics, School of MedicineIndiana UniversityIndianapolisINUSA
| | - Marco Brotto
- Bone‐Muscle Research Center, College of Nursing and Health InnovationUniversity of Texas‐ArlingtonArlingtonTXUSA
| | - Alexander G Robling
- Indiana Center for Musculoskeletal Health, Department of Anatomy, Cell Biology and Physiology, School of MedicineIndiana UniversityIndianapolisINUSA
| | - Lynda F Bonewald
- Indiana Center for Musculoskeletal Health, Department of Anatomy, Cell Biology and Physiology, School of MedicineIndiana UniversityIndianapolisINUSA
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Abstract
PURPOSE OF THE REVIEW The purpose of this review is to summarize the role of the osteocyte in muscle atrophy in cancer patients, sarcopenia, spinal cord injury, Duchenne's muscular dystrophy, and other conditions associated with muscle deterioration. RECENT FINDINGS One type of bone cell, the osteocyte, appears to play a major role in muscle and bone crosstalk, whether physiological or pathological. Osteocytes are cells living within the bone-mineralized matrix. These cells are connected to each other by means of dendrites to create an intricately connected network. The osteocyte network has been shown to respond to different types of stimuli such as mechanical unloading, immobilization, aging, and cancer by producing osteocytes-derived factors. It is now becoming clear that some of these factors including sclerostin, RANKL, TGF-β, and TNF-α have detrimental effects on skeletal muscle. Bone and muscle not only communicate mechanically but also biochemically. Osteocyte-derived factors appear to contribute to the pathogenesis of muscle disease and could be used as a cellular target for new therapeutic approaches.
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Affiliation(s)
- Anika Shimonty
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Lynda F Bonewald
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA
- Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Fabrizio Pin
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA.
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA.
- Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, USA.
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Williams JN, Irwin M, Li Y, Kambrath AV, Mattingly BT, Patel S, Kittaka M, Collins RN, Clough NA, Doud EH, Mosley AL, Bellido T, Bruzzaniti A, Plotkin LI, Trinidad JC, Thompson WR, Bonewald LF, Sankar U. Osteocyte-Derived CaMKK2 Regulates Osteoclasts and Bone Mass in a Sex-Dependent Manner through Secreted Calpastatin. Int J Mol Sci 2023; 24:4718. [PMID: 36902150 PMCID: PMC10003151 DOI: 10.3390/ijms24054718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 02/17/2023] [Accepted: 02/22/2023] [Indexed: 03/05/2023] Open
Abstract
Calcium/calmodulin (CaM)-dependent protein kinase kinase 2 (CaMKK2) regulates bone remodeling through its effects on osteoblasts and osteoclasts. However, its role in osteocytes, the most abundant bone cell type and the master regulator of bone remodeling, remains unknown. Here we report that the conditional deletion of CaMKK2 from osteocytes using Dentine matrix protein 1 (Dmp1)-8kb-Cre mice led to enhanced bone mass only in female mice owing to a suppression of osteoclasts. Conditioned media isolated from female CaMKK2-deficient osteocytes inhibited osteoclast formation and function in in vitro assays, indicating a role for osteocyte-secreted factors. Proteomics analysis revealed significantly higher levels of extracellular calpastatin, a specific inhibitor of calcium-dependent cysteine proteases calpains, in female CaMKK2 null osteocyte conditioned media, compared to media from female control osteocytes. Further, exogenously added non-cell permeable recombinant calpastatin domain I elicited a marked, dose-dependent inhibition of female wild-type osteoclasts and depletion of calpastatin from female CaMKK2-deficient osteocyte conditioned media reversed the inhibition of matrix resorption by osteoclasts. Our findings reveal a novel role for extracellular calpastatin in regulating female osteoclast function and unravel a novel CaMKK2-mediated paracrine mechanism of osteoclast regulation by female osteocytes.
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Affiliation(s)
- Justin N. Williams
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Mavis Irwin
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yong Li
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Anuradha Valiya Kambrath
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Brett T. Mattingly
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Sheel Patel
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Division of Biomedical Science, Marian University College of Osteopathic Medicine, Indianapolis, IN 46022, USA
| | - Mizuho Kittaka
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indianapolis, IN 46202, USA
| | - Rebecca N. Collins
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Nicholas A. Clough
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Emma H. Doud
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Amber L. Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Teresita Bellido
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Angela Bruzzaniti
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indianapolis, IN 46202, USA
| | - Lilian I. Plotkin
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Jonathan C. Trinidad
- Department of Chemistry, Biological Mass Spectrometry Facility, Indiana University, Bloomington, IN 47405, USA
| | - William R. Thompson
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Physical Therapy, School of Health and Human Sciences, Indianapolis, IN 46202, USA
| | - Lynda F. Bonewald
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Uma Sankar
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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9
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Agoro R, Nookaew I, Noonan ML, Marambio YG, Liu S, Chang W, Gao H, Hibbard LM, Metzger CE, Horan D, Thompson WR, Xuei X, Liu Y, Zhang C, Robling AG, Bonewald LF, Wan J, White KE. Single cell cortical bone transcriptomics define novel osteolineage gene sets altered in chronic kidney disease. Front Endocrinol (Lausanne) 2023; 14:1063083. [PMID: 36777346 PMCID: PMC9910177 DOI: 10.3389/fendo.2023.1063083] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 01/04/2023] [Indexed: 01/28/2023] Open
Abstract
INTRODUCTION Due to a lack of spatial-temporal resolution at the single cell level, the etiologies of the bone dysfunction caused by diseases such as normal aging, osteoporosis, and the metabolic bone disease associated with chronic kidney disease (CKD) remain largely unknown. METHODS To this end, flow cytometry and scRNAseq were performed on long bone cells from Sost-cre/Ai9+ mice, and pure osteolineage transcriptomes were identified, including novel osteocyte-specific gene sets. RESULTS Clustering analysis isolated osteoblast precursors that expressed Tnc, Mmp13, and Spp1, and a mature osteoblast population defined by Smpd3, Col1a1, and Col11a1. Osteocytes were demarcated by Cd109, Ptprz1, Ramp1, Bambi, Adamts14, Spns2, Bmp2, WasI, and Phex. We validated our in vivo scRNAseq using integrative in vitro promoter occupancy via ATACseq coupled with transcriptomic analyses of a conditional, temporally differentiated MSC cell line. Further, trajectory analyses predicted osteoblast-to-osteocyte transitions via defined pathways associated with a distinct metabolic shift as determined by single-cell flux estimation analysis (scFEA). Using the adenine mouse model of CKD, at a time point prior to major skeletal alterations, we found that gene expression within all stages of the osteolineage was disturbed. CONCLUSION In sum, distinct populations of osteoblasts/osteocytes were defined at the single cell level. Using this roadmap of gene assembly, we demonstrated unrealized molecular defects across multiple bone cell populations in a mouse model of CKD, and our collective results suggest a potentially earlier and more broad bone pathology in this disease than previously recognized.
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Affiliation(s)
- Rafiou Agoro
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Intawat Nookaew
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, United States
| | - Megan L. Noonan
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Yamil G. Marambio
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Sheng Liu
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Wennan Chang
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Electrical and Computer Engineering, Purdue University, Indianapolis, IN, United States
| | - Hongyu Gao
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
- Center for Medical Genomics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Lainey M. Hibbard
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Corinne E. Metzger
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Daniel Horan
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - William R. Thompson
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Xiaoling Xuei
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Yunlong Liu
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
- Center for Medical Genomics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Chi Zhang
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Electrical and Computer Engineering, Purdue University, Indianapolis, IN, United States
| | - Alexander G. Robling
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Lynda F. Bonewald
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, United States
| | - Jun Wan
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Kenneth E. White
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Medicine/Nephrology, Indiana University School of Medicine, Indianapolis, IN, United States
- *Correspondence: Kenneth E. White,
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10
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Yoshimoto T, Kittaka M, Doan AAP, Urata R, Prideaux M, Rojas RE, Harding CV, Henry Boom W, Bonewald LF, Greenfield EM, Ueki Y. Osteocytes directly regulate osteolysis via MYD88 signaling in bacterial bone infection. Nat Commun 2022; 13:6648. [PMID: 36333322 PMCID: PMC9636212 DOI: 10.1038/s41467-022-34352-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022] Open
Abstract
The impact of bone cell activation on bacterially-induced osteolysis remains elusive. Here, we show that matrix-embedded osteocytes stimulated with bacterial pathogen-associated molecular patterns (PAMPs) directly drive bone resorption through an MYD88-regulated signaling pathway. Mice lacking MYD88, primarily in osteocytes, protect against osteolysis caused by calvarial injections of bacterial PAMPs and resist alveolar bone resorption induced by oral Porphyromonas gingivalis (Pg) infection. In contrast, mice with targeted MYD88 restoration in osteocytes exhibit osteolysis with inflammatory cell infiltration. In vitro, bacterial PAMPs induce significantly higher expression of the cytokine RANKL in osteocytes than osteoblasts. Mechanistically, activation of the osteocyte MYD88 pathway up-regulates RANKL by increasing binding of the transcription factors CREB and STAT3 to Rankl enhancers and by suppressing K48-ubiquitination of CREB/CREB binding protein and STAT3. Systemic administration of an MYD88 inhibitor prevents jawbone loss in Pg-driven periodontitis. These findings reveal that osteocytes directly regulate inflammatory osteolysis in bone infection, suggesting that MYD88 and downstream RANKL regulators in osteocytes are therapeutic targets for osteolysis in periodontitis and osteomyelitis.
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Affiliation(s)
- Tetsuya Yoshimoto
- Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indianapolis, IN, 46202-5126, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202-5126, USA
| | - Mizuho Kittaka
- Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indianapolis, IN, 46202-5126, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202-5126, USA
| | - Andrew Anh Phuong Doan
- Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indianapolis, IN, 46202-5126, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202-5126, USA
| | - Rina Urata
- Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indianapolis, IN, 46202-5126, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202-5126, USA
| | - Matthew Prideaux
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202-5126, USA
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202-5126, USA
| | | | - Clifford V Harding
- Department of Pathology, Case Western Reserve University & University Hospitals Cleveland Medical Center, Cleveland, OH, 44106-4960, USA
| | - W Henry Boom
- Department of Pathology, Case Western Reserve University & University Hospitals Cleveland Medical Center, Cleveland, OH, 44106-4960, USA
- Department of Medicine, Case Western Reserve University & University Hospitals Cleveland Medical Center, Cleveland, OH, 44106-4960, USA
- Department of Molecular Biology and Microbiology, Case Western Reserve University & University Hospitals Cleveland Medical Center, Cleveland, OH, 44106-4960, USA
| | - Lynda F Bonewald
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202-5126, USA
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202-5126, USA
| | - Edward M Greenfield
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202-5126, USA
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202-5126, USA
- Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202-5126, USA
| | - Yasuyoshi Ueki
- Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indianapolis, IN, 46202-5126, USA.
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202-5126, USA.
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11
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Pin F, Jones AJ, Huot JR, Narasimhan A, Zimmers TA, Bonewald LF, Bonetto A. RANKL Blockade Reduces Cachexia and Bone Loss Induced by Non-Metastatic Ovarian Cancer in Mice. J Bone Miner Res 2022; 37:381-396. [PMID: 34904285 PMCID: PMC8940654 DOI: 10.1002/jbmr.4480] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/18/2021] [Accepted: 11/20/2021] [Indexed: 12/13/2022]
Abstract
Tumor- and bone-derived soluble factors have been proposed to participate in the alterations of skeletal muscle size and function in cachexia. We previously showed that mice bearing ovarian cancer (OvCa) exhibit cachexia associated with marked bone loss, whereas bone-targeting agents, such as bisphosphonates, are able to preserve muscle mass in animals exposed to anticancer drugs. De-identified CT images and plasma samples from female patients affected with OvCa were used for body composition assessment and quantification of circulating cross-linked C-telopeptide type I (CTX-I) and receptor activator of NF-kB ligand (RANKL), respectively. Female mice bearing ES-2 tumors were used to characterize cancer- and RANKL-associated effects on muscle and bone. Murine C2C12 and human HSMM myotube cultures were used to determine the OvCa- and RANKL-dependent effects on myofiber size. To the extent of isolating new regulators of bone and muscle in cachexia, here we demonstrate that subjects affected with OvCa display evidence of cachexia and increased bone turnover. Similarly, mice carrying OvCa present high RANKL levels. By using in vitro and in vivo experimental models, we found that elevated circulating RANKL is sufficient to cause skeletal muscle atrophy and bone resorption, whereas bone preservation by means of antiresorptive and anti-RANKL treatments concurrently benefit muscle mass and function in cancer cachexia. Altogether, our data contribute to identifying RANKL as a novel therapeutic target for the treatment of musculoskeletal complications associated with RANKL-expressing non-metastatic cancers. © 2021 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Fabrizio Pin
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Alexander J Jones
- Department of Otolaryngology-Head & Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Joshua R Huot
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ashok Narasimhan
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Teresa A Zimmers
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Otolaryngology-Head & Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA.,Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, USA.,Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Lynda F Bonewald
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA.,Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, USA.,Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Andrea Bonetto
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Otolaryngology-Head & Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA.,Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, USA.,Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA
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12
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Glorieux FH, Bonewald LF, Harvey NC, van der Meulen MCH. Potential influences on optimizing long-term musculoskeletal health in children and adolescents with X-linked hypophosphatemia (XLH). Orphanet J Rare Dis 2022; 17:30. [PMID: 35101067 PMCID: PMC8802511 DOI: 10.1186/s13023-021-02156-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/19/2021] [Indexed: 12/20/2022] Open
Abstract
In recent years, much progress has been made in understanding the mechanisms of bone growth and development over a lifespan, including the crosstalk between muscle and bone, to achieve optimal structure and function. While there have been significant advances in understanding how to help improve and maintain bone health in normal individuals, there is limited knowledge on whether these mechanisms apply or are compromised in pathological states. X-linked hypophosphatemia (XLH) (ORPHA:89936) is a rare, heritable, renal phosphate-wasting disorder. The resultant chronic hypophosphatemia leads to progressive deterioration in musculoskeletal function, including impaired growth, rickets, and limb deformities in children, as well as lifelong osteomalacia with reduced bone quality and impaired muscle structure and function. The clinical manifestations of the disease vary both in presentation and severity in affected individuals, and many of the consequences of childhood defects persist into adulthood, causing significant morbidity that impacts physical function and quality of life. Intervention to restore phosphate levels early in life during the critical stages of skeletal development in children with XLH could optimize growth and may prevent or reduce bone deformities in childhood. A healthier bone structure, together with improved muscle function, can lead to physical activity enhancing musculoskeletal health throughout life. In adults, continued management may help to maintain the positive effects acquired from childhood treatment, thereby slowing or halting disease progression. In this review, we summarize the opinions from members of a working group with expertise in pediatrics, epidemiology, and bone, joint and muscle biology, on potential outcomes for people with XLH, who have been optimally treated from an early age and continue treatment throughout life.
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Affiliation(s)
| | - Lynda F Bonewald
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, USA
| | - Nicholas C Harvey
- MRC Lifecourse Epidemiology Centre, University of Southampton, Southampton, UK
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13
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Abstract
PURPOSE OF REVIEW While the function of osteocytes under physiologic conditions is well defined, their role and involvement in cancer disease remains relatively unexplored, especially in a context of non-bone metastatic cancer. This review will focus on describing the more advanced knowledge regarding the interactions between osteocytes and cancer. RECENT FINDINGS We will discuss the involvement of osteocytes in the onset and progression of osteosarcoma, with the common bone cancers, as well as the interaction that is established between osteocytes and multiple myeloma. Mechanisms responsible for cancer dissemination to bone, as frequently occur with advanced breast and prostate cancers, will be reviewed. While a role for osteocytes in the stimulation and proliferation of cancer cells has been reported, protective effects of osteocytes against bone colonization have been described as well, thus increasing ambiguity regarding the role of osteocytes in cancer progression and dissemination. Lastly, supporting the idea that skeletal defects can occur also in the absence of direct cancer dissemination or osteolytic lesions directly adjacent to the bone, our recent findings will be presented showing that in the absence of bone metastases, the bone microenvironment and, particularly, osteocytes, can manifest a clear and dramatic response to the distant, non-metastatic tumor. Our observations support new studies to clarify whether treatments designed to preserve the osteocytes can be combined with traditional anticancer therapies, even when bone is not directly affected by tumor growth.
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Affiliation(s)
- Fabrizio Pin
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Matt Prideaux
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Lynda F Bonewald
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
- Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Andrea Bonetto
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA.
- Department of Otolaryngology-Head & Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, USA.
- Department of Surgery, Indiana University School of Medicine, 980 W Walnut Street, R3-C522, Indianapolis, IN, 46202, USA.
- Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, USA.
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA.
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14
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Toda Nakamura M, Zhang H, Guo D, Ueharu H, Pan H, Scott G, Harris M, Ray M, Feng JQ, Harris SE, Bonewald LF, Mishina Y. Podoplanin is dispensable for mineralized tissue formation and maintenance in the Swiss outbred mouse background. Genesis 2021; 59:e23450. [PMID: 34487426 DOI: 10.1002/dvg.23450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 11/07/2022]
Abstract
Podoplanin, PDPN, is a mucin-type transmembrane glycoprotein widely expressed in many tissues, including lung, kidney, lymph nodes, and mineralized tissues. Its function is critical for lymphatic formation, differentiation of type I alveolar epithelial lung cells, and for bone response to biomechanical loading. It has previously been shown that Pdpn null mice die at birth due to respiratory failure emphasizing the importance of Pdpn in alveolar lung development. During the course of generation of Pdpn mutant mice, we found that most Pdpn null mice in the 129S6 and C57BL6/J mixed genetic background die at the perinatal stage, similar to previously published studies with Pdpn null mice, while all Pdpn null mice bred with Swiss outbred mice survived. Surviving mutant mice in the 129S6 and C57BL6/J mixed genetic background showed alterations in the osteocyte lacunocanalicular network, especially reduced osteocyte canaliculi in the tibial cortex with increased tibial trabecular bone. However, adult Pdpn null mice in the Swiss outbred background showed no overt differences in their osteocyte lacunocnalicular network, bone density, and no overt differences when challenged with exercise. Together, these data suggest that genetic variations present in the Swiss outbred mice compensate for the loss of function of PDPN in lung, kidney, and bone.
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Affiliation(s)
- Masako Toda Nakamura
- Department of Biologic and Materials Sciences & Prosthodontics, School of Dentistry, University of Michigan, Ann Arbor, Michigan, USA.,Section of Pediatric Dentistry, Department of Oral Growth and Development, Fukuoka Dental College, Fukuoka, Japan
| | - Honghao Zhang
- Department of Biologic and Materials Sciences & Prosthodontics, School of Dentistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Dayong Guo
- Department of Oral Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Hiroki Ueharu
- Department of Biologic and Materials Sciences & Prosthodontics, School of Dentistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Haichun Pan
- Department of Biologic and Materials Sciences & Prosthodontics, School of Dentistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Greg Scott
- Knock Out Core, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Marie Harris
- Department of Oral Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, Missouri, USA.,UT Health San Antonio, Graduate School of Biomedical Sciences, San Antonio, Texas, USA
| | - Manas Ray
- Knock Out Core, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Jiang Q Feng
- Department of Oral Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, Missouri, USA.,Department of Biomedical Sciences, Texas A&M College of Dentistry, Dallas, Texas, USA
| | - Stephen E Harris
- Department of Oral Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, Missouri, USA.,UT Health San Antonio, Graduate School of Biomedical Sciences, San Antonio, Texas, USA
| | - Lynda F Bonewald
- Department of Oral Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, Missouri, USA.,Indiana Center for Musculoskeletal Health and Department of Anatomy, Cell Biology and Physiology, Indiana University, Indianapolis, Indiana, USA
| | - Yuji Mishina
- Department of Biologic and Materials Sciences & Prosthodontics, School of Dentistry, University of Michigan, Ann Arbor, Michigan, USA
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15
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Ito N, Prideaux M, Wijenayaka AR, Yang D, Ormsby RT, Bonewald LF, Atkins GJ. Sclerostin Directly Stimulates Osteocyte Synthesis of Fibroblast Growth Factor-23. Calcif Tissue Int 2021; 109:66-76. [PMID: 33616712 DOI: 10.1007/s00223-021-00823-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 02/05/2021] [Indexed: 12/16/2022]
Abstract
Osteocyte produced fibroblast growth factor 23 (FGF23) is the key regulator of serum phosphate (Pi) homeostasis. The interplay between parathyroid hormone (PTH), FGF23 and other proteins that regulate FGF23 production and serum Pi levels is complex and incompletely characterised. Evidence suggests that the protein product of the SOST gene, sclerostin (SCL), also a PTH target and also produced by osteocytes, plays a role in FGF23 expression, however the mechanism for this effect is unclear. Part of the problem of understanding the interplay of these mediators is the complex multi-organ system that achieves Pi homeostasis in vivo. In the current study, we sought to address this using a cell line model of the osteocyte, IDG-SW3, known to express FGF23 at both the mRNA and protein levels. In cultures of differentiated IDG-SW3 cells, both PTH1-34 and recombinant human (rh) SCL remarkably induced Fgf23 mRNA expression dose-dependently within 3 h. Both rhPTH1-34 and rhSCL also strongly induced C-terminal FGF23 protein secretion. Secreted intact FGF23 levels remained unchanged, consistent with constitutive post-translational cleavage of FGF23 in this cell model. Both rhPTH1-34 and rhSCL treatments significantly suppressed mRNA levels of Phex, Dmp1 and Enpp1 mRNA, encoding putative negative regulators of FGF23 levels, and induced Galnt3 mRNA expression, encoding N-acetylgalactosaminyl-transferase 3 (GalNAc-T3), which protects FGF23 from furin-like proprotein convertase-mediated cleavage. The effect of both rhPTH1-34 and rhSCL was antagonised by pre-treatment with the NF-κβ signalling inhibitors, BAY11 and TPCK. RhSCL also stimulated FGF23 mRNA expression in ex vivo cultures of human bone. These findings provide evidence for the direct regulation of FGF23 expression by sclerostin. Locally expressed sclerostin via the induction of FGF23 in osteocytes thus has the potential to contribute to the regulation of Pi homeostasis.
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Affiliation(s)
- Nobuaki Ito
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA, 5000, Australia
- Division of Nephrology and Endocrinology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Matthew Prideaux
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA, 5000, Australia
- School of Medicine, Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA
| | - Asiri R Wijenayaka
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA, 5000, Australia
| | - Dongqing Yang
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA, 5000, Australia
| | - Renee T Ormsby
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA, 5000, Australia
- Brigham and Women's Hospital, Boston, MA, USA
| | - Lynda F Bonewald
- School of Medicine, Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA
| | - Gerald J Atkins
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA, 5000, Australia.
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16
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Abstract
Cancer-induced muscle wasting, i.e. cachexia, is associated with different types of cancer such as pancreatic, colorectal, lung, liver, gastric and esophageal. Cachexia affects prognosis and survival in cancer, and it is estimated that it will be the ultimate cause of death for up to 30% of cancer patients. Musculoskeletal alterations are known hallmarks of cancer cachexia, with skeletal muscle atrophy and weakness as the most studied. Recent evidence has shed light on the presence of bone loss in cachectic patients, even in the absence of bone-metastatic disease. In particular, we and others have shown that muscle and bone communicate by exchanging paracrine and endocrine factors, known as myokines and osteokines. This review will focus on describing the role of the most studied myokines, such as myostatin, irisin, the muscle metabolite β-aminoisobutyric acid, BAIBA, and IL-6, and osteokines, including TGF-β, osteocalcin, sclerostin, RANKL, PTHrP, FGF23, and the lipid mediator, PGE2 during cancer-induced cachexia. The interplay of muscle and bone factors, together with tumor-derived soluble factors, characterizes a complex clinical scenario in which musculoskeletal alterations are amongst the most debilitating features. Understanding and targeting the "secretome" of cachectic patients will likely represent a promising strategy to preserve bone and muscle during cancer cachexia thereby enhancing recovery.
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Affiliation(s)
- Fabrizio Pin
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Lynda F Bonewald
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.,Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA.,Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Andrea Bonetto
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.,Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA.,Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN 46202, USA.,Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA.,Department of Otolaryngology - Head & Neck Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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17
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Abstract
Osteocytes are an ancient cell, appearing in fossilized skeletal remains of early fish and dinosaurs. Despite its relative high abundance, even in the context of nonskeletal cells, the osteocyte is perhaps among the least studied cells in all of vertebrate biology. Osteocytes are cells embedded in bone, able to modify their surrounding extracellular matrix via specialized molecular remodeling mechanisms that are independent of the bone forming osteoblasts and bone-resorbing osteoclasts. Osteocytes communicate with osteoclasts and osteoblasts via distinct signaling molecules that include the RankL/OPG axis and the Sost/Dkk1/Wnt axis, among others. Osteocytes also extend their influence beyond the local bone environment by functioning as an endocrine cell that controls phosphate reabsorption in the kidney, insulin secretion in the pancreas, and skeletal muscle function. These cells are also finely tuned sensors of mechanical stimulation to coordinate with effector cells to adjust bone mass, size, and shape to conform to mechanical demands.
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Affiliation(s)
- Alexander G Robling
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA;
| | - Lynda F Bonewald
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA;
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18
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Prideaux M, Kitase Y, Kimble M, O'Connell TM, Bonewald LF. Taurine, an osteocyte metabolite, protects against oxidative stress-induced cell death and decreases inhibitors of the Wnt/β-catenin signaling pathway. Bone 2020; 137:115374. [PMID: 32330695 PMCID: PMC7369146 DOI: 10.1016/j.bone.2020.115374] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 04/16/2020] [Accepted: 04/18/2020] [Indexed: 12/17/2022]
Abstract
Taurine has been shown to have positive effects on bone mass, which are thought to be due in part to its cytoprotective effects on osteoblasts and here we show that taurine also protects osteocytes against cell death due to reactive oxygen species. Using the IDG-SW3 cell line, the expression of the taurine uptake transporter Taut/Slc6a6 is increased during osteoblast to osteocyte differentiation. Taurine had no effect on genes associated with osteoblast to osteocyte differentiation such as Dmp1, Phex or osteocalcin, even at high doses, but a slight yet significant inhibition of alkaline phosphatase was observed at the highest dose (50 mM). No effect was seen on the osteoclast regulatory genes Rankl and Opg, however the wnt antagonist Sost/sclerostin was potently and dose-dependently downregulated in response to taurine supplementation. Taurine also significantly inhibited Dkk1 mRNA expression, but only at 50 mM. Interestingly, osteocytes were found to also be able to synthesize taurine intracellularly, potentially as a self-protective mechanism, but do not secrete the metabolite. A highly significant increase in the expression of cysteine dioxygenase (Cdo), a key enzyme necessary for the production of taurine, was observed with osteoblast to osteocyte differentiation along with a decrease in methionine, the precursor of taurine. For the first time, we describe the synthesis of taurine by osteocytes, potentially to preserve viability and to regulate bone formation through inhibition of sclerostin.
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Affiliation(s)
- M Prideaux
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States of America; Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, United States of America.
| | - Y Kitase
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States of America; Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, United States of America
| | - M Kimble
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - T M O'Connell
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States of America; Department of Otolaryngology, Indiana University, Indianapolis, United States of America
| | - L F Bonewald
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States of America; Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, United States of America; Department of Orthopedic Surgery, Indiana University, Indianapolis, United States of America
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19
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Sego TJ, Prideaux M, Sterner J, McCarthy BP, Li P, Bonewald LF, Ekser B, Tovar A, Jeshua Smith L. Cover Image. Biotechnol Bioeng 2020. [DOI: 10.1002/bit.27040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- T. J. Sego
- Department of Intelligent Systems EngineeringIndiana University Bloomington Indiana
| | - Matthew Prideaux
- Indiana Center for Musculoskeletal HealthIndiana University Indianapolis Indiana
- Department of Anatomy and Cell BiologyIndiana University School of Medicine Indianapolis Indiana
| | - Jane Sterner
- Radiology and Imaging SciencesIndiana University School of Medicine Indianapolis Indiana
- 3D Bioprinting CoreIndiana University School of Medicine Indianapolis Indiana
| | - Brian Paul McCarthy
- Radiology and Imaging SciencesIndiana University School of Medicine Indianapolis Indiana
| | - Ping Li
- Division of Transplant Surgery, Department of SurgeryIndiana University School of Medicine Indianapolis Indiana
| | - Lynda F. Bonewald
- Indiana Center for Musculoskeletal HealthIndiana University Indianapolis Indiana
- Department of Anatomy and Cell BiologyIndiana University School of Medicine Indianapolis Indiana
- Department of Orthopaedic SurgeryIndiana University School of Medicine Indianapolis Indiana
| | - Burcin Ekser
- Division of Transplant Surgery, Department of SurgeryIndiana University School of Medicine Indianapolis Indiana
| | - Andres Tovar
- Department of Mechanical and Energy EngineeringIndiana University‐Purdue University Indianapolis Indianapolis Indiana
| | - Lester Jeshua Smith
- Radiology and Imaging SciencesIndiana University School of Medicine Indianapolis Indiana
- 3D Bioprinting CoreIndiana University School of Medicine Indianapolis Indiana
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20
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Wang H, Li T, Wang X, Yin X, Zhao N, Zou S, Duan P, Bonewald LF. The role of sphingosine-1-phosphate signaling pathway in cementocyte mechanotransduction. Biochem Biophys Res Commun 2020; 523:595-601. [PMID: 31941604 DOI: 10.1016/j.bbrc.2020.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 01/02/2020] [Indexed: 02/08/2023]
Abstract
Iatrogenic external root resorption can become a serious pathological condition with clinical tooth movement. Little is known regarding how cementum responds to mechanical loading in contrast to bone, especially under compressive stress. In the field of bone biology, several studies have established the contribution of sphingosine-1-phosphate (S1P) signaling in bone remodeling, mechanical transduction and homeostasis. As osteocytes and cementocytes share similar morphological and functional characteristics, this study aimed to investigate the mechanotransduction ability of cementocytes and to explore the contribution of S1P signaling under compressive stress induced mechanotransduction. We found that compressive stress inhibited major S1P signaling and promoted the expression of anabolic factors in IDG-CM6 cells, a novel immortalized murine cementocyte cell line. By inhibiting S1P signaling, we verified that S1P signaling played a vital role in regulating the expression of the mechanotransduction factors prostaglandin E2 (PGE2) and β-catenin, as well as factors responsible for cementogenesis and cementoclastogenesis in IDG-CM6 cells. These results support the hypothesis that cementocytes act as key mechanically responsive cells in cementum, responding to compressive stress and directing local cementum metabolism.
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Affiliation(s)
- Han Wang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Tiancheng Li
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Xin Wang
- Oral Diagnosis and Treatment Center, Aviation General Hospital, China Medical University, Beijing, China
| | - Xing Yin
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Ning Zhao
- Department of Orthodontics, Shanghai Key Laboratory of Stomatology, Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shujuan Zou
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Peipei Duan
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
| | - Lynda F Bonewald
- Departments of Anatomy, Cell Biology & Physiology and Orthopaedic Surgery, Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States
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21
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Sego TJ, Prideaux M, Sterner J, McCarthy BP, Li P, Bonewald LF, Ekser B, Tovar A, Jeshua Smith L. Computational fluid dynamic analysis of bioprinted self-supporting perfused tissue models. Biotechnol Bioeng 2019; 117:798-815. [PMID: 31788785 PMCID: PMC7015804 DOI: 10.1002/bit.27238] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 11/12/2019] [Accepted: 11/22/2019] [Indexed: 01/11/2023]
Abstract
Natural tissues are incorporated with vasculature, which is further integrated with a cardiovascular system responsible for driving perfusion of nutrient‐rich oxygenated blood through the vasculature to support cell metabolism within most cell‐dense tissues. Since scaffold‐free biofabricated tissues being developed into clinical implants, research models, and pharmaceutical testing platforms should similarly exhibit perfused tissue‐like structures, we generated a generalizable biofabrication method resulting in self‐supporting perfused (SSuPer) tissue constructs incorporated with perfusible microchannels and integrated with the modular FABRICA perfusion bioreactor. As proof of concept, we perfused an MLO‐A5 osteoblast‐based SSuPer tissue in the FABRICA. Although our resulting SSuPer tissue replicated vascularization and perfusion observed in situ, supported its own weight, and stained positively for mineral using Von Kossa staining, our in vitro results indicated that computational fluid dynamics (CFD) should be used to drive future construct design and flow application before further tissue biofabrication and perfusion. We built a CFD model of the SSuPer tissue integrated in the FABRICA and analyzed flow characteristics (net force, pressure distribution, shear stress, and oxygen distribution) through five SSuPer tissue microchannel patterns in two flow directions and at increasing flow rates. Important flow parameters include flow direction, fully developed flow, and tissue microchannel diameters matched and aligned with bioreactor flow channels. We observed that the SSuPer tissue platform is capable of providing direct perfusion to tissue constructs and proper culture conditions (oxygenation, with controllable shear and flow rates), indicating that our approach can be used to biofabricate tissue representing primary tissues and that we can model the system in silico.
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Affiliation(s)
- T J Sego
- Department of Intelligent Systems Engineering, Indiana University, Bloomington, Indiana
| | - Matthew Prideaux
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, Indiana.,Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Jane Sterner
- Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana.,3D Bioprinting Core, Indiana University School of Medicine, Indianapolis, Indiana
| | - Brian Paul McCarthy
- Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana
| | - Ping Li
- Division of Transplant Surgery, Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana
| | - Lynda F Bonewald
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, Indiana.,Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana.,Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, Indiana
| | - Burcin Ekser
- Division of Transplant Surgery, Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana
| | - Andres Tovar
- Department of Mechanical and Energy Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana
| | - Lester Jeshua Smith
- Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana.,3D Bioprinting Core, Indiana University School of Medicine, Indianapolis, Indiana
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22
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Huang J, Wang K, Shiflett LA, Brotto L, Bonewald LF, Wacker MJ, Dallas SL, Brotto M. Fibroblast growth factor 9 (FGF9) inhibits myogenic differentiation of C2C12 and human muscle cells. Cell Cycle 2019; 18:3562-3580. [PMID: 31735119 PMCID: PMC6927711 DOI: 10.1080/15384101.2019.1691796] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Osteoporosis and sarcopenia (osteosarcopenia (OS)) are twin-aging diseases. The biochemical crosstalk between muscle and bone seems to play a role in OS. We have previously shown that osteocytes produce soluble factors with beneficial effects on muscle and vice versa. Recently, enhanced FGF9 production was observed in the OmGFP66 osteogenic cell line. To test its role in myogenic differentiation, C2C12 myoblasts were treated with recombinant FGF9. FGF9 as low as 10 ng/mL inhibited myogenic differentiation, suggesting that FGF9 might be a potential inhibitory factor produced from bone cells with effects on muscle cells. FGF9 (10–50 ng/mL) significantly decreased mRNA expression of MyoG and Mhc while increasing the expression of Myostatin. Consistent with the phenotype, RT-qPCR array revealed that FGF9 (10 ng/mL) increased the expression of Icam1 while decreased the expression of Wnt1 and Wnt6 decreased, respectively. FGF9 decreased caffeine-induced Ca2+ release from the sarcoplasmic reticulum (SR) of C2C12 myotubes and reduced the expression of genes (i.e. Cacna1s, RyR2, Naftc3) directly associated with intracellular Ca2+ homeostasis. Myogenic differentiation in human skeletal muscle cells was similarly inhibited by FGF9 but required higher doses of 200 ng/mL FGF9. FGF9 was also shown to stimulate C2C12 myoblast proliferation. FGF2 and the FGF9 subfamily members FGF16 and FGF20 also inhibited C2C12 myoblast differentiation and enhanced proliferation. Intriguingly, the differentiation inhibition was independent of proliferation enhancement. These findings suggest that FGF9 may modulate myogenesis via a complex signaling mechanism.
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Affiliation(s)
- Jian Huang
- Bone-Muscle Research Center, College of Nursing & Health Innovation, the University of Texas at Arlington, Arlington, TX, USA
| | - Kun Wang
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Lora A Shiflett
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Leticia Brotto
- Bone-Muscle Research Center, College of Nursing & Health Innovation, the University of Texas at Arlington, Arlington, TX, USA
| | - Lynda F Bonewald
- Indiana Center for Musculoskeletal Health, School of Medicine, Indiana University, Indianapolis, IN USA
| | - Michael J Wacker
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Sarah L Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Marco Brotto
- Bone-Muscle Research Center, College of Nursing & Health Innovation, the University of Texas at Arlington, Arlington, TX, USA
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23
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Kim H, Wrann CD, Jedrychowski M, Vidoni S, Kitase Y, Nagano K, Zhou C, Chou J, Parkman VJA, Novick SJ, Strutzenberg TS, Pascal BD, Le PT, Brooks DJ, Roche AM, Gerber KK, Mattheis L, Chen W, Tu H, Bouxsein ML, Griffin PR, Baron R, Rosen CJ, Bonewald LF, Spiegelman BM. Irisin Mediates Effects on Bone and Fat via αV Integrin Receptors. Cell 2019; 175:1756-1768.e17. [PMID: 30550785 DOI: 10.1016/j.cell.2018.10.025] [Citation(s) in RCA: 337] [Impact Index Per Article: 67.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 08/27/2018] [Accepted: 10/07/2018] [Indexed: 01/08/2023]
Abstract
Irisin is secreted by muscle, increases with exercise, and mediates certain favorable effects of physical activity. In particular, irisin has been shown to have beneficial effects in adipose tissues, brain, and bone. However, the skeletal response to exercise is less clear, and the receptor for irisin has not been identified. Here we show that irisin binds to proteins of the αV class of integrins, and biophysical studies identify interacting surfaces between irisin and αV/β5 integrin. Chemical inhibition of the αV integrins blocks signaling and function by irisin in osteocytes and fat cells. Irisin increases both osteocytic survival and production of sclerostin, a local modulator of bone remodeling. Genetic ablation of FNDC5 (or irisin) completely blocks osteocytic osteolysis induced by ovariectomy, preventing bone loss and supporting an important role of irisin in skeletal remodeling. Identification of the irisin receptor should greatly facilitate our understanding of irisin's function in exercise and human health.
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Affiliation(s)
- Hyeonwoo Kim
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Cell Biology, Harvard University Medical School, Boston, MA 02115, USA
| | - Christiane D Wrann
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Cell Biology, Harvard University Medical School, Boston, MA 02115, USA; Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA 02219, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Mark Jedrychowski
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Cell Biology, Harvard University Medical School, Boston, MA 02115, USA
| | - Sara Vidoni
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Cell Biology, Harvard University Medical School, Boston, MA 02115, USA
| | - Yukiko Kitase
- Department of Anatomy and Cell Biology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - Kenichi Nagano
- Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Chenhe Zhou
- Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Joshua Chou
- Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Virginia-Jeni A Parkman
- Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Scott J Novick
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Timothy S Strutzenberg
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Bruce D Pascal
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Phuong T Le
- Maine Medical Center Research Institute, Scarborough, ME 04074, USA
| | - Daniel J Brooks
- Center for Advanced Orthopedic Studies, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Alexander M Roche
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Cell Biology, Harvard University Medical School, Boston, MA 02115, USA
| | - Kaitlyn K Gerber
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Cell Biology, Harvard University Medical School, Boston, MA 02115, USA
| | - Laura Mattheis
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Cell Biology, Harvard University Medical School, Boston, MA 02115, USA
| | | | - Hua Tu
- LakePharma, Inc., San Carlos, CA 94070, USA
| | - Mary L Bouxsein
- Center for Advanced Orthopedic Studies, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Department of Orthopedic Surgery, Harvard Medical School, Boston, MA 02215, USA
| | - Patrick R Griffin
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Roland Baron
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA; Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Clifford J Rosen
- Maine Medical Center Research Institute, Scarborough, ME 04074, USA
| | - Lynda F Bonewald
- Department of Anatomy and Cell Biology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA; Department of Orthopedic Surgery, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - Bruce M Spiegelman
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Cell Biology, Harvard University Medical School, Boston, MA 02115, USA.
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24
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Kim H, Wrann CD, Jedrychowski M, Vidoni S, Kitase Y, Nagano K, Zhou C, Chou J, Parkman VJA, Novick SJ, Strutzenberg TS, Pascal BD, Le PT, Brooks DJ, Roche AM, Gerber KK, Mattheis L, Chen W, Tu H, Bouxsein ML, Griffin PR, Baron R, Rosen CJ, Bonewald LF, Spiegelman BM. Irisin Mediates Effects on Bone and Fat via αV Integrin Receptors. Cell 2019; 178:507-508. [PMID: 31299203 DOI: 10.1016/j.cell.2019.06.028] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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25
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Wang K, Le L, Chun BM, Tiede-Lewis LM, Shiflett LA, Prideaux M, Campos RS, Veno PA, Xie Y, Dusevich V, Bonewald LF, Dallas SL. A Novel Osteogenic Cell Line That Differentiates Into GFP-Tagged Osteocytes and Forms Mineral With a Bone-Like Lacunocanalicular Structure. J Bone Miner Res 2019; 34:979-995. [PMID: 30882939 PMCID: PMC7350928 DOI: 10.1002/jbmr.3720] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 02/15/2019] [Accepted: 02/22/2019] [Indexed: 01/20/2023]
Abstract
Osteocytes, the most abundant cells in bone, were once thought to be inactive, but are now known to have multifunctional roles in bone, including in mechanotransduction, regulation of osteoblast and osteoclast function and phosphate homeostasis. Because osteocytes are embedded in a mineralized matrix and are challenging to study, there is a need for new tools and cell models to understand their biology. We have generated two clonal osteogenic cell lines, OmGFP66 and OmGFP10, by immortalization of primary bone cells from mice expressing a membrane-targeted GFP driven by the Dmp1-promoter. One of these clones, OmGFP66, has unique properties compared with previous osteogenic and osteocyte cell models and forms 3-dimensional mineralized bone-like structures, containing highly dendritic GFP-positive osteocytes, embedded in clearly defined lacunae. Confocal and electron microscopy showed that structurally and morphologically, these bone-like structures resemble bone in vivo, even mimicking the lacunocanalicular ultrastructure and 3D spacing of in vivo osteocytes. In osteogenic conditions, OmGFP66 cells express alkaline phosphatase (ALP), produce a mineralized type I collagen matrix, and constitutively express the early osteocyte marker, E11/gp38. With differentiation they express osteocyte markers, Dmp1, Phex, Mepe, Fgf23, and the mature osteocyte marker, Sost. They also express RankL, Opg, and Hif1α, and show expected osteocyte responses to PTH, including downregulation of Sost, Dmp1, and Opg and upregulation of RankL and E11/gp38. Live cell imaging revealed the dynamic process by which OmGFP66 bone-like structures form, the motile properties of embedding osteocytes and the integration of osteocyte differentiation with mineralization. The OmGFP10 clone showed an osteocyte gene expression profile similar to OmGFP66, but formed less organized bone nodule-like mineral, similar to other osteogenic cell models. Not only do these cell lines provide useful new tools for mechanistic and dynamic studies of osteocyte differentiation, function, and biomineralization, but OmGFP66 cells have the unique property of modeling osteocytes in their natural bone microenvironment. © 2019 American Society for Bone and Mineral Research.
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Affiliation(s)
- Kun Wang
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA
| | - Lisa Le
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA
| | - Brad M Chun
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA
| | - LeAnn M Tiede-Lewis
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA
| | - Lora A Shiflett
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA
| | - Matthew Prideaux
- Department of Anatomy and Cell Biology, School of Medicine, Indiana University, Indianapolis, IN, USA
| | - Richard S Campos
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA
| | - Patricia A Veno
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA
| | - Yixia Xie
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA
| | - Vladimir Dusevich
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA
| | - Lynda F Bonewald
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA.,Department of Anatomy and Cell Biology, School of Medicine, Indiana University, Indianapolis, IN, USA.,Department of Orthopaedic Surgery, Indiana University, Indianapolis, IN, USA
| | - Sarah L Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA
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26
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Bonewald LF. Effects of muscle‐derived BAIBA on osteocytes with aging. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.15.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Lynda F. Bonewald
- Anatomy and Cell BiologyIndiana Center for Musculoskeletal HealthIndiana UniversityIndianapolisIN
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27
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Kim H, Wrann CD, Jedrychowski M, Kitase Y, Nagano K, Strutzenberg TS, Bouxsein ML, Griffin PR, Baron R, Rosen CJ, Bonewald LF, Spiegelman BM. Irisin Mediates Effects on Bone via αV Integrin Receptors. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.15.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Hyeonwoo Kim
- Dana‐Farber Cancer InstituteBostonMA
- Harvard Medical SchoolBostonMA
| | - Christiane D. Wrann
- Dana‐Farber Cancer InstituteBostonMA
- Harvard Medical SchoolBostonMA
- Massachusetts General HospitalCharlestownMA
| | | | | | | | | | - Mary L. Bouxsein
- Harvard Medical SchoolBostonMA
- Beth Israel Deaconess Medical CenterBostonMA
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28
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Maurel DB, Matsumoto T, Vallejo JA, Johnson ML, Dallas SL, Kitase Y, Brotto M, Wacker MJ, Harris MA, Harris SE, Bonewald LF. Characterization of a novel murine Sost ER T2 Cre model targeting osteocytes. Bone Res 2019; 7:6. [PMID: 30820362 PMCID: PMC6382861 DOI: 10.1038/s41413-018-0037-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 09/25/2018] [Accepted: 10/19/2018] [Indexed: 12/28/2022] Open
Abstract
Transgenic mice are widely used to delete or overexpress genes in a cell specific manner to advance knowledge of bone biology, function and disease. While numerous Cre models exist to target gene recombination in osteoblasts and osteoclasts, few target osteocytes specifically, particularly mature osteocytes. Our goal was to create a spatial and temporal conditional Cre model using tamoxifen to induce Cre activity in mature osteocytes using a Bac construct containing the 5' and 3' regions of the Sost gene (Sost ERT2 Cre). Four founder lines were crossed with the Ai9 Cre reporter mice. One founder line showed high and specific activity in mature osteocytes. Bones and organs were imaged and fluorescent signal quantitated. While no activity was observed in 2 day old pups, by 2 months of age some osteocytes were positive as osteocyte Cre activity became spontaneous or 'leaky' with age. The percentage of positive osteocytes increased following tamoxifen injection, especially in males, with 43% to 95% positive cells compared to 19% to 32% in females. No signal was observed in any bone surface cell, bone marrow, nor in muscle with or without tamoxifen injection. No spontaneous signal was observed in any other organ. However, with tamoxifen injection, a few positive cells were observed in kidney, eye, lung, heart and brain. All other organs, 28 in total, were negative with tamoxifen injection. However, with age, a muscle phenotype was apparent in the Sost-ERT2 Cre mice. Therefore, although this mouse model may be useful for targeting gene deletion or expression to mature osteocytes, the muscle phenotype may restrict the use of this model to specific applications and should be considered when interpreting data.
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Affiliation(s)
- Delphine B Maurel
- 1Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City School of Dentistry, Kansas City, MO USA.,7Present Address: Pharmaceutical Sciences Department, Universite de Bordeaux, Bio-Tis, INSERM Unité 1026 BioTis, 146 Rue Léo Saignat, 33076 Bordeaux, France
| | - Tsutomu Matsumoto
- 2Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN USA
| | - Julian A Vallejo
- 1Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City School of Dentistry, Kansas City, MO USA
| | - Mark L Johnson
- 1Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City School of Dentistry, Kansas City, MO USA
| | - Sarah L Dallas
- 1Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City School of Dentistry, Kansas City, MO USA
| | - Yukiko Kitase
- 2Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN USA
| | - Marco Brotto
- 3Bone-Muscle Collaborative Sciences, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, USA
| | - Michael J Wacker
- 4Department of Biomedical Sciences, University of Missouri-Kansas City School of Medicine, Kansas City, MO USA
| | - Marie A Harris
- 5University of Texas Health Science Center, San Antonio, TX USA
| | | | - Lynda F Bonewald
- 1Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City School of Dentistry, Kansas City, MO USA.,2Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN USA.,6Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, IN USA
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Essex AL, Pin F, Huot JR, Bonewald LF, Plotkin LI, Bonetto A. Bisphosphonate Treatment Ameliorates Chemotherapy-Induced Bone and Muscle Abnormalities in Young Mice. Front Endocrinol (Lausanne) 2019; 10:809. [PMID: 31803146 PMCID: PMC6877551 DOI: 10.3389/fendo.2019.00809] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 11/04/2019] [Indexed: 12/14/2022] Open
Abstract
Chemotherapy is frequently accompanied by several side effects, including nausea, diarrhea, anorexia and fatigue. Evidence from ours and other groups suggests that chemotherapy can also play a major role in causing not only cachexia, but also bone loss. This complicates prognosis and survival among cancer patients, affects quality of life, and can increase morbidity and mortality rates. Recent findings suggest that soluble factors released from resorbing bone directly contribute to loss of muscle mass and function secondary to metastatic cancer. However, it remains unknown whether similar mechanisms also take place following treatments with anticancer drugs. In this study, we found that young male CD2F1 mice (8-week old) treated with the chemotherapeutic agent cisplatin (2.5 mg/kg) presented marked loss of muscle and bone mass. Myotubes exposed to bone conditioned medium from cisplatin-treated mice showed severe atrophy (-33%) suggesting a bone to muscle crosstalk. To test this hypothesis, mice were administered cisplatin in combination with an antiresorptive drug to determine if preservation of bone mass has an effect on muscle mass and strength following chemotherapy treatment. Mice received cisplatin alone or combined with zoledronic acid (ZA; 5 μg/kg), a bisphosphonate routinely used for the treatment of osteoporosis. We found that cisplatin resulted in progressive loss of body weight (-25%), in line with reduced fat (-58%) and lean (-17%) mass. As expected, microCT bone histomorphometry analysis revealed significant reduction in bone mass following administration of chemotherapy, in line with reduced trabecular bone volume (BV/TV) and number (Tb.N), as well as increased trabecular separation (Tb.Sp) in the distal femur. Conversely, trabecular bone was protected when cisplatin was administered in combination with ZA. Interestingly, while the animals exposed to chemotherapy presented significant muscle wasting (~-20% vs. vehicle-treated mice), the administration of ZA in combination with cisplatin resulted in preservation of muscle mass (+12%) and strength (+42%). Altogether, these observations support our hypothesis of bone factors targeting muscle and suggest that pharmacological preservation of bone mass can benefit muscle mass and function following chemotherapy.
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Affiliation(s)
- Alyson L. Essex
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Fabrizio Pin
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Joshua R. Huot
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Lynda F. Bonewald
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States
- Simon Comprehensive Cancer Center, Indiana University, Indianapolis, IN, United States
- Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, IN, United States
- IUPUI Center for Cachexia Research, Innovation and Therapy, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Lilian I. Plotkin
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Andrea Bonetto
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, United States
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States
- Simon Comprehensive Cancer Center, Indiana University, Indianapolis, IN, United States
- IUPUI Center for Cachexia Research, Innovation and Therapy, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Otolaryngology – Head & Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, United States
- *Correspondence: Andrea Bonetto
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Pin F, Bonetto A, Bonewald LF, Klein GL. Molecular Mechanisms Responsible for the Rescue Effects of Pamidronate on Muscle Atrophy in Pediatric Burn Patients. Front Endocrinol (Lausanne) 2019; 10:543. [PMID: 31447786 PMCID: PMC6692456 DOI: 10.3389/fendo.2019.00543] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 07/19/2019] [Indexed: 12/25/2022] Open
Abstract
Not only has pamidronate been shown to prevent inflammation associated bone resorption following burn injury, it also reduces protein breakdown in muscle. The aim of this study was to identify the molecular mechanisms responsible for muscle mass rescue in pamidronate treated compared to placebo/standard of care-treated burn patients. Mature myotubes, generated by differentiating murine C2C12 myoblasts, were exposed for 48 h to 1 or 5% serum obtained from 3 groups of children: normal unburned, burned receiving standard of care, and burned receiving standard of care with pamidronate. Exposure to serum from burned patients caused dose-dependent myotube atrophy compared to normal serum as expected based on previous observations of muscle atrophy induced by burn injury in humans and animals. The size of C2C12 myotubes was partially protected upon exposure to the serum from patients treated with pamidronate correlating with the rescue of muscle size previously observed in these patients. At the molecular signaling level, serum from both pamidronate and non-pamidronate-treated burn patients increased pSTAT3/STAT3 and pERK1/2/ERK1/2 compared to normal serum with no significant differences between the two groups of burn patients indicating elevated production of inflammatory cytokines. However, serum from pamidronate-treated patients restored the phosphorylation of AKT and mTOR and reduced protein ubiquitination when compared to burn serum alone, suggesting a prevention of muscle catabolism and a restoration of muscle anabolism. Myotube atrophy induced by burn serum was partially rescued after exposure to a pan anti-TGFβ-1/2/3 antibody, suggesting that this signaling pathway is partially responsible for the atrophy and that bisphosphonate protection of bones from resorption during burn injury prevents the release of muscle pro-catabolic factors such as TGFβ into the circulation.
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Affiliation(s)
- Fabrizio Pin
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, United States
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Andrea Bonetto
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, United States
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, United States
- Simon Cancer Center, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Otolaryngology—Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Lynda F. Bonewald
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, United States
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Gordon L. Klein
- Department of Orthopaedic Surgery, University of Texas Medical Branch, Galveston, TX, United States
- *Correspondence: Gordon L. Klein
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Colditz J, Thiele S, Baschant U, Niehrs C, Bonewald LF, Hofbauer LC, Rauner M. Postnatal Skeletal Deletion of Dickkopf-1 Increases Bone Formation and Bone Volume in Male and Female Mice, Despite Increased Sclerostin Expression. J Bone Miner Res 2018; 33:1698-1707. [PMID: 29734465 DOI: 10.1002/jbmr.3463] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 04/16/2018] [Accepted: 04/28/2018] [Indexed: 12/14/2022]
Abstract
The Wnt antagonist Dickkopf-1 (Dkk1) is a negative regulator of osteoblast function and bone mass. However, because of the lack of appropriate models, many aspects of its role in the regulation of postnatal bone turnover and its cellular source have remained unknown. In this study, we deleted Dkk1 postnatally and in different cell types using various Cre-drivers (Rosa26-ERT2-Cre, Osx-cre, Dmp1-Cre) and assessed to which extent cells of the osteoblastic lineage contribute to the effects of Dkk1 on bone turnover and homeostasis. Female and male mice were examined at 12 weeks of age. Mice with a global or cell type-specific deletion of Dkk1 showed a two- to threefold higher bone volume compared with their Cre-negative littermates. The mineral apposition rate and the bone formation rate were increased two- to fourfold in all three mouse lines, despite a significant increase in systemic and skeletal levels of sclerostin. Dkk1 deletion further reduced the number of osteoclasts about twofold, which was accompanied by a strong decrease in the receptor activator of nuclear factor-κB ligand/osteoprotegerin mRNA ratio in femoral bone. Despite similar increases in bone mass, the deletion of Dkk1 in osterix-expressing cells reduced circulating Dkk1 significantly (males, -79%; females, -77%), whereas they were not changed in Dkk1fl/fl ;Dmp1-Cre mice. However, both lines showed significantly reduced Dkk1 mRNA levels in bone. In summary, we show that lack of Dkk1 in cells of the osteoblastic lineage leads to high bone mass with increased bone formation, despite increased levels of sclerostin. Moreover, the majority of systemic Dkk1 appears to originate from osteoprogenitors but not from mature osteoblasts or osteocytes. Nevertheless, the amount of Dkk1 produced locally by more mature osteogenic cells is sufficient to modulate bone mass. Thus, this study highlights the importance of local Wnt signaling on postnatal bone homeostasis. © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
- Juliane Colditz
- Department of Medicine III, Technische Universität Dresden, Dresden, Germany.,Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Sylvia Thiele
- Department of Medicine III, Technische Universität Dresden, Dresden, Germany.,Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Ulrike Baschant
- Department of Medicine III, Technische Universität Dresden, Dresden, Germany.,Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Christof Niehrs
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, Heidelberg, Germany.,Institute of Molecular Biology, Mainz, Germany
| | - Lynda F Bonewald
- Indiana Center for Musculoskeletal Health, Departments of Anatomy and Cell Biology and Orthopaedic Surgery, School of Medicine, Indianapolis, IN, USA
| | - Lorenz C Hofbauer
- Department of Medicine III, Technische Universität Dresden, Dresden, Germany.,Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany.,Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
| | - Martina Rauner
- Department of Medicine III, Technische Universität Dresden, Dresden, Germany.,Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
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Tsourdi E, Jähn K, Rauner M, Busse B, Bonewald LF. Physiological and pathological osteocytic osteolysis. J Musculoskelet Neuronal Interact 2018; 18:292-303. [PMID: 30179206 PMCID: PMC6146198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Osteocytes, the most abundant bone cell in the adult skeleton, can function as mechanosensors directing osteoblast and osteoclast function in order to maintain optimal load bearing bone in addition to functioning as endocrine cells regulating phosphate metabolism. A controversial function, previously overlooked or denied, has been osteocytes as regulators of calcium metabolism. Early histologists upon observing enlarged osteocyte lacunae in bone sections proposed that mature osteocytes could remove their perilacunar matrix, a term called "osteocytic osteolysis". New insights into this process have occurred during the last decade using novel technology thereby providing a means to identify molecular mechanisms responsible for osteocytic osteolysis. As release of calcium from a mineralized matrix requires a more acidic pH and specialized enzymes, it was proposed that osteocytes may utilize similar molecular mechanisms as osteoclasts to remove mineral. The idea that a cell descended from mesenchymal progenitors (the osteocyte) could function similarly to a cell descended from hematopoietic progenitors (the osteoclast) was challenged as being improbable. Here we review the molecular mechanisms behind this osteocyte function, the role of osteocytic osteolysis in health and disease, and the capacity of the osteocyte to reverse the osteolytic process by replacing the removed matrix, a revived osteoblast function.
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Affiliation(s)
- Elena Tsourdi
- Department of Medicine III, Technische Universität Dresden Medical Center, Dresden, Germany,Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany,Corresponding author: Elena Tsourdi, M.D., Division of Endocrinology, Diabetes and Metabolic Bone Diseases, Department of Medicine III, Technische Universität Dresden Medical Center, Fetscherstrasse 74, 01307 Dresden, Germany E-mail:
| | - Katharina Jähn
- Department for Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Martina Rauner
- Department of Medicine III, Technische Universität Dresden Medical Center, Dresden, Germany,Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Björn Busse
- Department for Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Lynda F. Bonewald
- Indiana Center for Musculoskeletal Health, VanNuys Medical Science Building, Indianapolis, USA
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33
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Pin F, Barreto R, Kitase Y, Mitra S, Erne CE, Novinger LJ, Zimmers TA, Couch ME, Bonewald LF, Bonetto A. Growth of ovarian cancer xenografts causes loss of muscle and bone mass: a new model for the study of cancer cachexia. J Cachexia Sarcopenia Muscle 2018; 9:685-700. [PMID: 30009406 PMCID: PMC6104117 DOI: 10.1002/jcsm.12311] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 04/07/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Cachexia frequently occurs in women with advanced ovarian cancer (OC), along with enhanced inflammation. Despite being responsible for one third of all cancer deaths, cachexia is generally under-studied in OC due to a limited number of pre-clinical animal models. We aimed to address this gap by characterizing the cachectic phenotype in a mouse model of OC. METHODS Nod SCID gamma mice (n = 6-10) were injected intraperitoneally with 1 × 107 ES-2 human OC cells to mimic disseminated abdominal disease. Muscle size and strength, as well as bone morphometry, were assessed. Tumour-derived effects on muscle fibres were investigated in C2C12 myotube cultures. IL-6 levels were detected in serum and ascites from tumour hosts, as well as in tumour sections. RESULTS In about 2 weeks, ES-2 cells developed abdominal tumours infiltrating omentum, mesentery, and adjacent organs. The ES-2 tumours caused severe cachexia with marked loss of body weight (-12%, P < 0.01) and ascites accumulation in the peritoneal cavity (4.7 ± 1.5 mL). Skeletal muscles appeared markedly smaller in the tumour-bearing mice (approximately -35%, P < 0.001). Muscle loss was accompanied by fibre atrophy, consistent with reduced muscle cross-sectional area (-34%, P < 0.01) and muscle weakness (-50%, P < 0.001). Body composition assessment by dual-energy X-ray absorptiometry revealed decreased bone mineral density (-8%, P < 0.01) and bone mineral content (-19%, P < 0.01), also consistent with reduced trabecular bone in both femurs and vertebrae, as suggested by micro-CT imaging of bone morphometry. In the ES-2 mouse model, cachexia was also associated with high tumour-derived IL-6 levels in plasma and ascites (26.3 and 279.6 pg/mL, respectively) and with elevated phospho-STAT3 (+274%, P < 0.001), reduced phospho-AKT (-44%, P < 0.001) and decreased mitochondrial proteins, as well as with increased protein ubiquitination (+42%, P < 0.001) and expression of ubiquitin ligases in the skeletal muscle of tumour hosts. Similarly, ES-2 conditioned medium directly induced fibre atrophy in C2C12 mouse myotubes (-16%, P < 0.001), consistent with elevated phospho-STAT3 (+1.4-fold, P < 0.001) and altered mitochondrial homoeostasis and metabolism, while inhibition of the IL-6/STAT3 signalling by means of INCB018424 was sufficient to restore the myotubes size. CONCLUSIONS Our results suggest that the development of ES-2 OC promotes muscle atrophy in both in vivo and in vitro conditions, accompanied by loss of bone mass, enhanced muscle protein catabolism, abnormal mitochondrial homoeostasis, and elevated IL-6 levels. Therefore, this represents an appropriate model for the study of OC cachexia. Our model will aid in identifying molecular mediators that could be effectively targeted in order to improve muscle wasting associated with OC.
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Affiliation(s)
- Fabrizio Pin
- Department of Anatomy and Cell BiologyIndiana University School of MedicineIndianapolisIN46202USA
- Indiana Center for Musculoskeletal HealthIndiana University School of MedicineIndianapolisIN46202USA
| | - Rafael Barreto
- Department of SurgeryIndiana University School of MedicineIndianapolisIN46202USA
| | - Yukiko Kitase
- Department of Anatomy and Cell BiologyIndiana University School of MedicineIndianapolisIN46202USA
- Indiana Center for Musculoskeletal HealthIndiana University School of MedicineIndianapolisIN46202USA
| | - Sumegha Mitra
- Department of Biochemistry and Molecular BiologyIndiana UniversityBloomingtonIN47405USA
- Simon Cancer CenterIndiana University School of MedicineIndianapolisIN46202USA
| | - Carlie E. Erne
- Department of SurgeryIndiana University School of MedicineIndianapolisIN46202USA
| | - Leah J. Novinger
- Department of Otolaryngology ‐ Head and Neck SurgeryIndiana University School of MedicineIndianapolisIN46202USA
| | - Teresa A. Zimmers
- Department of Anatomy and Cell BiologyIndiana University School of MedicineIndianapolisIN46202USA
- Indiana Center for Musculoskeletal HealthIndiana University School of MedicineIndianapolisIN46202USA
- Department of SurgeryIndiana University School of MedicineIndianapolisIN46202USA
- Simon Cancer CenterIndiana University School of MedicineIndianapolisIN46202USA
- Department of Otolaryngology ‐ Head and Neck SurgeryIndiana University School of MedicineIndianapolisIN46202USA
- IUPUI Center for Cachexia Research Innovation and TherapyIndiana University School of MedicineIndianapolisIN46202USA
| | - Marion E. Couch
- Indiana Center for Musculoskeletal HealthIndiana University School of MedicineIndianapolisIN46202USA
- Simon Cancer CenterIndiana University School of MedicineIndianapolisIN46202USA
- Department of Otolaryngology ‐ Head and Neck SurgeryIndiana University School of MedicineIndianapolisIN46202USA
- IUPUI Center for Cachexia Research Innovation and TherapyIndiana University School of MedicineIndianapolisIN46202USA
| | - Lynda F. Bonewald
- Department of Anatomy and Cell BiologyIndiana University School of MedicineIndianapolisIN46202USA
- Indiana Center for Musculoskeletal HealthIndiana University School of MedicineIndianapolisIN46202USA
- Simon Cancer CenterIndiana University School of MedicineIndianapolisIN46202USA
- IUPUI Center for Cachexia Research Innovation and TherapyIndiana University School of MedicineIndianapolisIN46202USA
| | - Andrea Bonetto
- Department of Anatomy and Cell BiologyIndiana University School of MedicineIndianapolisIN46202USA
- Indiana Center for Musculoskeletal HealthIndiana University School of MedicineIndianapolisIN46202USA
- Department of SurgeryIndiana University School of MedicineIndianapolisIN46202USA
- Simon Cancer CenterIndiana University School of MedicineIndianapolisIN46202USA
- Department of Otolaryngology ‐ Head and Neck SurgeryIndiana University School of MedicineIndianapolisIN46202USA
- IUPUI Center for Cachexia Research Innovation and TherapyIndiana University School of MedicineIndianapolisIN46202USA
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Tiede-Lewis LM, Xie Y, Hulbert MA, Campos R, Dallas MR, Dusevich V, Bonewald LF, Dallas SL. Degeneration of the osteocyte network in the C57BL/6 mouse model of aging. Aging (Albany NY) 2018; 9:2190-2208. [PMID: 29074822 PMCID: PMC5680562 DOI: 10.18632/aging.101308] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/15/2017] [Indexed: 11/25/2022]
Abstract
Age-related bone loss and associated fracture risk are major problems in musculoskeletal health. Osteocytes have emerged as key regulators of bone mass and as a therapeutic target for preventing bone loss. As aging is associated with changes in the osteocyte lacunocanalicular system, we focused on the responsible cellular mechanisms in osteocytes. Bone phenotypic analysis was performed in young-(5mo) and aged-(22mo) C57BL/6 mice and changes in bone structure/geometry correlated with alterations in osteocyte parameters determined using novel multiplexed-3D-confocal imaging techniques. Age-related bone changes analogous to those in humans were observed, including increased cortical diameter, decreased cortical thickness, reduced trabecular BV/TV and cortical porosities. This was associated with a dramatic reduction in osteocyte dendrite number and cell density, particularly in females, where osteocyte dendricity decreased linearly from 5, 12, 18 to 22mo and correlated significantly with cortical bone parameters. Reduced dendricity preceded decreased osteocyte number, suggesting dendrite loss may trigger loss of viability. Age-related degeneration of osteocyte networks may impair bone anabolic responses to loading and gender differences in osteocyte cell body and lacunar fluid volumes we observed in aged mice may lead to gender-related differences in mechanosensitivity. Therapies to preserve osteocyte dendricity and viability may be beneficial for bone health in aging.
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Affiliation(s)
- LeAnn M Tiede-Lewis
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, Kansas City, MO 64108, USA
| | - Yixia Xie
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, Kansas City, MO 64108, USA
| | - Molly A Hulbert
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, Kansas City, MO 64108, USA
| | - Richard Campos
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, Kansas City, MO 64108, USA
| | - Mark R Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, Kansas City, MO 64108, USA
| | - Vladimir Dusevich
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, Kansas City, MO 64108, USA
| | - Lynda F Bonewald
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, Kansas City, MO 64108, USA.,Departments of Anatomy and Cell Biology and Orthopaedic Surgery, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - Sarah L Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, Kansas City, MO 64108, USA
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Lu Y, Kamel-El Sayed SA, Wang K, Tiede-Lewis LM, Grillo MA, Veno PA, Dusevich V, Phillips CL, Bonewald LF, Dallas SL. Live Imaging of Type I Collagen Assembly Dynamics in Osteoblasts Stably Expressing GFP and mCherry-Tagged Collagen Constructs. J Bone Miner Res 2018; 33:1166-1182. [PMID: 29461659 PMCID: PMC6425932 DOI: 10.1002/jbmr.3409] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 01/22/2018] [Accepted: 02/02/2018] [Indexed: 11/12/2022]
Abstract
Type I collagen is the most abundant extracellular matrix protein in bone and other connective tissues and plays key roles in normal and pathological bone formation as well as in connective tissue disorders and fibrosis. Although much is known about the collagen biosynthetic pathway and its regulatory steps, the mechanisms by which it is assembled extracellularly are less clear. We have generated GFPtpz and mCherry-tagged collagen fusion constructs for live imaging of type I collagen assembly by replacing the α2(I)-procollagen N-terminal propeptide with GFPtpz or mCherry. These novel imaging probes were stably transfected into MLO-A5 osteoblast-like cells and fibronectin-null mouse embryonic fibroblasts (FN-null-MEFs) and used for imaging type I collagen assembly dynamics and its dependence on fibronectin. Both fusion proteins co-precipitated with α1(I)-collagen and remained intracellular without ascorbate but were assembled into α1(I) collagen-containing extracellular fibrils in the presence of ascorbate. Immunogold-EM confirmed their ultrastuctural localization in banded collagen fibrils. Live cell imaging in stably transfected MLO-A5 cells revealed the highly dynamic nature of collagen assembly and showed that during assembly the fibril networks are continually stretched and contracted due to the underlying cell motion. We also observed that cell-generated forces can physically reshape the collagen fibrils. Using co-cultures of mCherry- and GFPtpz-collagen expressing cells, we show that multiple cells contribute collagen to form collagen fiber bundles. Immuno-EM further showed that individual collagen fibrils can receive contributions of collagen from more than one cell. Live cell imaging in FN-null-MEFs expressing GFPtpz-collagen showed that collagen assembly was both dependent upon and dynamically integrated with fibronectin assembly. These GFP-collagen fusion constructs provide a powerful tool for imaging collagen in living cells and have revealed novel and fundamental insights into the dynamic mechanisms for the extracellular assembly of collagen. © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
- Yongbo Lu
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, 650 E. 25 Street, Kansas City, MO 64108
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, 3302 Gaston Ave., Dallas, TX 75246
| | - Suzan A. Kamel-El Sayed
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, 650 E. 25 Street, Kansas City, MO 64108
- Biomedical Sciences Department, Oakland University William Beaumont School of Medicine, 414 O’Dowd Hall, Rochester MI, 48309
- Medical Physiology Department, Assiut University School of Medicine 71516, Asyut, Egypt
| | - Kun Wang
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, 650 E. 25 Street, Kansas City, MO 64108
| | - LeAnn M. Tiede-Lewis
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, 650 E. 25 Street, Kansas City, MO 64108
| | - Michael A. Grillo
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, 650 E. 25 Street, Kansas City, MO 64108
| | - Patricia A. Veno
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, 650 E. 25 Street, Kansas City, MO 64108
| | - Vladimir Dusevich
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, 650 E. 25 Street, Kansas City, MO 64108
| | - Charlotte L. Phillips
- Departments of Biochemistry and Child Health, University of Missouri Columbia, 117 Schweitzer Hall, Columbia, MO 65211
| | - Lynda F. Bonewald
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, 650 E. 25 Street, Kansas City, MO 64108
- Departments of Anatomy and Cell Biology and Orthopaedic Surgery, Indiana University, Indianapolis, IN 46202
| | - Sarah L. Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, 650 E. 25 Street, Kansas City, MO 64108
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36
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Yajima A, Tsuchiya K, Bonewald LF, Inaba M, Tominaga Y, Tanizawa T, Ito A, Nitta K. Case report: Electron microscopic evaluation of bone from a patient treated with cinacalcet hydrochloride, maxacalcitol, and alfacalcidol for hyperparathyroid bone disease with secondary hyperparathyroidism. Osteoporos Int 2018; 29:1203-1209. [PMID: 29492624 DOI: 10.1007/s00198-018-4402-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 01/18/2018] [Indexed: 11/27/2022]
Abstract
Evaluation of bone is of great importance in chronic kidney disease patients, as these patients are at an increased risk for fractures. We treated a hemodialysis patient suffering from hyperparathyroid bone disease with cinacalcet hydrochloride and concurrent administration of maxacalcitol and alfacalcidol for a year. Hyperparathyroid bone disease is characterized by cortical thinning, increased cortical porosity, reduced trabecular bone volume, and increased hypomineralized matrix volume, and there is little information to date about the effects of treatment with cinacalcet hydrochloride on the bone fragility in patients with hyperparathyroid bone disease. In the present study, histological and backscattered electron microscopic evaluation of this combination treatment revealed an excellent improvement of both bone volume and bone morphology. This treatment improved cortical thinning, cortical porosity, and trabecular thinning. Furthermore, the treatment also reduced hypomineralized matrix volume, indicative of improved mineralization by osteocytes. We speculate that the intermittent maxacalcitol administration may have effectively stimulated the vitamin D receptors expressed on osteocytes and osteoblasts, resulting in increased mineralization. Our approach for evaluating the bone in patients with chronic kidney disease by backscattered electron microscopy is novel.
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Affiliation(s)
- A Yajima
- Department of Medicine, Kidney Center, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan.
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA.
| | - K Tsuchiya
- Department of Blood Purification, Kidney Center, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan
| | - L F Bonewald
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Oral and Craniofacial Sciences, University of Missouri, School of Dentistry, Kansas City, MI, USA
| | - M Inaba
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka City University, Abeno-ku, Osaka, Japan
| | - Y Tominaga
- Department of Endocrine Surgery, Nagoya Second Red Cross Hospital, Nagoya, Aichi, Japan
| | - T Tanizawa
- Department of Orthopedic Surgery, Tanizawa Clinic, Niigata, Niigata, Japan
| | - A Ito
- Ito Bone Histomorphometry Institute, Niigata, Niigata, Japan
| | - K Nitta
- Department of Medicine, Kidney Center, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan
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37
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Morrell AE, Brown GN, Robinson ST, Sattler RL, Baik AD, Zhen G, Cao X, Bonewald LF, Jin W, Kam LC, Guo XE. Mechanically induced Ca 2+ oscillations in osteocytes release extracellular vesicles and enhance bone formation. Bone Res 2018; 6:6. [PMID: 29581909 PMCID: PMC5859015 DOI: 10.1038/s41413-018-0007-x] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 11/23/2017] [Indexed: 02/01/2023] Open
Abstract
The vast osteocytic network is believed to orchestrate bone metabolic activity in response to mechanical stimuli through production of sclerostin, RANKL, and osteoprotegerin (OPG). However, the mechanisms of osteocyte mechanotransduction remain poorly understood. We've previously shown that osteocyte mechanosensitivity is encoded through unique intracellular calcium (Ca2+) dynamics. Here, by simultaneously monitoring Ca2+ and actin dynamics in single cells exposed to fluid shear flow, we detected actin network contractions immediately upon onset of flow-induced Ca2+ transients, which were facilitated by smooth muscle myosin and further confirmed in native osteocytes ex vivo. Actomyosin contractions have been linked to the secretion of extracellular vesicles (EVs), and our studies demonstrate that mechanical stimulation upregulates EV production in osteocytes through immunostaining for the secretory vesicle marker Lysosomal-associated membrane protein 1 (LAMP1) and quantifying EV release in conditioned medium, both of which are blunted when Ca2+ signaling was inhibited by neomycin. Axial tibia compression was used to induce anabolic bone formation responses in mice, revealing upregulated LAMP1 and expected downregulation of sclerostin in vivo. This load-related increase in LAMP1 expression was inhibited in neomycin-injected mice compared to vehicle. Micro-computed tomography revealed significant load-related increases in both trabecular bone volume fraction and cortical thickness after two weeks of loading, which were blunted by neomycin treatment. In summary, we found mechanical stimulation of osteocytes activates Ca2+-dependent contractions and enhances the production and release of EVs containing bone regulatory proteins. Further, blocking Ca2+ signaling significantly attenuates adaptation to mechanical loading in vivo, suggesting a critical role for Ca2+-mediated signaling in bone adaptation.
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Affiliation(s)
- Andrea E. Morrell
- Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY USA
| | - Genevieve N. Brown
- Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY USA
| | - Samuel T. Robinson
- Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY USA
| | - Rachel L. Sattler
- Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY USA
| | - Andrew D. Baik
- Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY USA
| | - Gehua Zhen
- Center for Musculoskeletal Research, Department of Orthopaedic Surgery, Johns Hopkins University, Baltimore, MD USA
| | - Xu Cao
- Center for Musculoskeletal Research, Department of Orthopaedic Surgery, Johns Hopkins University, Baltimore, MD USA
| | - Lynda F. Bonewald
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN USA
| | - Weiyang Jin
- Microscale Biocomplexity Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY USA
| | - Lance C. Kam
- Microscale Biocomplexity Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY USA
| | - X. Edward Guo
- Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY USA
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38
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Kitase Y, Vallejo JA, Gutheil W, Vemula H, Jähn K, Yi J, Zhou J, Brotto M, Bonewald LF. β-aminoisobutyric Acid, l-BAIBA, Is a Muscle-Derived Osteocyte Survival Factor. Cell Rep 2018; 22:1531-1544. [PMID: 29425508 PMCID: PMC5832359 DOI: 10.1016/j.celrep.2018.01.041] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 11/03/2017] [Accepted: 01/12/2018] [Indexed: 01/04/2023] Open
Abstract
Exercise has beneficial effects on metabolism and on tissues. The exercise-induced muscle factor β-aminoisobutyric acid (BAIBA) plays a critical role in the browning of white fat and in insulin resistance. Here we show another function for BAIBA, that of a bone-protective factor that prevents osteocyte cell death induced by reactive oxygen species (ROS). l-BAIBA was as or more protective than estrogen or N-acetyl cysteine, signaling through the Mas-Related G Protein-Coupled Receptor Type D (MRGPRD) to prevent the breakdown of mitochondria due to ROS. BAIBA supplied in drinking water prevented bone loss and loss of muscle function in the murine hindlimb unloading model, a model of osteocyte apoptosis. The protective effect of BAIBA was lost with age, not due to loss of the muscle capacity to produce BAIBA but likely to reduced Mrgprd expression with aging. This has implications for understanding the attenuated effect of exercise on bone with aging.
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Affiliation(s)
- Yukiko Kitase
- Department of Anatomy and Cell Biology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA.
| | - Julian A Vallejo
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA; Department of Oral & Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - William Gutheil
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Harika Vemula
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Katharina Jähn
- Department of Osteology and Biomechanics, University of Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jianxun Yi
- Kansas City University of Medicine and Bioscience, Kansas City, MO 64106, USA
| | - Jingsong Zhou
- Kansas City University of Medicine and Bioscience, Kansas City, MO 64106, USA
| | - Marco Brotto
- Bone-Muscle Collaborative Science, College of Nursing & Health Innovation, University of Texas-Arlington, Arlington, TX 76019, USA
| | - Lynda F Bonewald
- Department of Anatomy and Cell Biology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA; Department of Orthopaedic Surgery, School of Medicine, Indiana University, Indianapolis, IN 46202, USA.
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39
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Barreto R, Kitase Y, Matsumoto T, Pin F, Colston KC, Couch KE, O'Connell TM, Couch ME, Bonewald LF, Bonetto A. ACVR2B/Fc counteracts chemotherapy-induced loss of muscle and bone mass. Sci Rep 2017; 7:14470. [PMID: 29089584 PMCID: PMC5665981 DOI: 10.1038/s41598-017-15040-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 10/20/2017] [Indexed: 01/06/2023] Open
Abstract
Chemotherapy promotes the development of cachexia, a debilitating condition characterized by muscle and fat loss. ACVR2B/Fc, an inhibitor of the Activin Receptor 2B signaling, has been shown to preserve muscle mass and prolong survival in tumor hosts, and to increase bone mass in models of osteogenesis imperfecta and muscular dystrophy. We compared the effects of ACVR2B/Fc on muscle and bone mass in mice exposed to Folfiri. In addition to impairing muscle mass and function, Folfiri had severe negative effects on bone, as shown by reduced trabecular bone volume fraction (BV/TV), thickness (Tb.Th), number (Tb.N), connectivity density (Conn.Dn), and by increased separation (Tb.Sp) in trabecular bone of the femur and vertebra. ACVR2B/Fc prevented the loss of muscle mass and strength, and the loss of trabecular bone in femurs and vertebrae following Folfiri administration. Neither Folfiri nor ACVR2B/Fc had effects on femoral cortical bone, as shown by unchanged cortical bone volume fraction (Ct.BV/TV), thickness (Ct.Th) and porosity. Our results suggest that Folfiri is responsible for concomitant muscle and bone degeneration, and that ACVR2B/Fc prevents these derangements. Future studies are required to determine if the same protective effects are observed in combination with other anticancer regimens or in the presence of cancer.
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Affiliation(s)
- Rafael Barreto
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Yukiko Kitase
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Tsutomu Matsumoto
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Fabrizio Pin
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Kyra C Colston
- Indianapolis Project STEM, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Katherine E Couch
- Indianapolis Project STEM, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Thomas M O'Connell
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Department of Otolaryngology - Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Simon Cancer Center, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,IUPUI Center for Cachexia Research Innovation and Therapy, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Marion E Couch
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Department of Otolaryngology - Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Simon Cancer Center, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,IUPUI Center for Cachexia Research Innovation and Therapy, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Lynda F Bonewald
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Simon Cancer Center, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,IUPUI Center for Cachexia Research Innovation and Therapy, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Andrea Bonetto
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA. .,Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA. .,Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, 46202, USA. .,Department of Otolaryngology - Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA. .,Simon Cancer Center, Indiana University School of Medicine, Indianapolis, IN, 46202, USA. .,IUPUI Center for Cachexia Research Innovation and Therapy, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
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40
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Huang J, Romero-Suarez S, Lara N, Mo C, Kaja S, Brotto L, Dallas SL, Johnson ML, Jähn K, Bonewald LF, Brotto M. Crosstalk between MLO-Y4 osteocytes and C2C12 muscle cells is mediated by the Wnt/β-catenin pathway. JBMR Plus 2017; 1:86-100. [PMID: 29104955 DOI: 10.1002/jbm4.10015] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
We examined the effects of osteocyte secreted factors on myogenesis and muscle function. MLO-Y4 osteocyte-like cell conditioned media (CM) (10%) increased ex vivo soleus muscle contractile force by ~25%. MLO-Y4 and primary osteocyte CM (1-10%) stimulated myogenic differentiation of C2C12 myoblasts, but 10% osteoblast CMs did not enhance C2C12 cell differentiation. Since WNT3a and WNT1 are secreted by osteocytes, and the expression level of Wnt3a is increased in MLO-Y4 cells by fluid flow shear stress, both were compared, showing WNT3a more potent than WNT1 in inducing myogenesis. Treatment of C2C12 myoblasts with WNT3a at concentrations as low as 0.5ng/mL mirrored the effects of both primary osteocyte and MLO-Y4 CM by inducing nuclear translocation of β-catenin with myogenic differentiation, suggesting that Wnts might be potential factors secreted by osteocytes that signal to muscle cells. Knocking down Wnt3a in MLO-Y4 osteocytes inhibited the effect of CM on C2C12 myogenic differentiation. Sclerostin (100ng/mL) inhibited both the effects of MLO-Y4 CM and WNT3a on C2C12 cell differentiation. RT-PCR array results supported the activation of the Wnt/β-catenin pathway by MLO-Y4 CM and WNT3a. These results were confirmed by qPCR showing up-regulation of myogenic markers and two Wnt/β-catenin downstream genes, Numb and Flh1. We postulated that MLO-Y4 CM/WNT3a could modulate intracellular calcium homeostasis as the trigger mechanism for the enhanced myogenesis and contractile force. MLO-Y4 CM and WNT3a increased caffeine-induced Ca2+ release from the sarcoplasmic reticulum (SR) of C2C12 myotubes and the expression of genes directly associated with intracellular Ca2+ signaling and homeostasis. Together, these data show that in vitro and ex vivo, osteocytes can stimulate myogenesis and enhance muscle contractile function and suggest that Wnts could be mediators of bone to muscle signaling, likely via modulation of intracellular Ca2+ signaling and the Wnt/β-Catenin pathway.
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Affiliation(s)
- Jian Huang
- Muscle Biology Research Group-MUBIG, School sof Nursing & Health Studies, University of Missouri- Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Sandra Romero-Suarez
- Muscle Biology Research Group-MUBIG, School sof Nursing & Health Studies, University of Missouri- Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Nuria Lara
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, 64108, USA
| | - Chenglin Mo
- Muscle Biology Research Group-MUBIG, School sof Nursing & Health Studies, University of Missouri- Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Simon Kaja
- Department of Ophthalmology, Vision Research Center, School of Medicine, University of Missouri-Kansas City, 2411 Holmes St., Kansas City, MO, 64108, USA
| | - Leticia Brotto
- Muscle Biology Research Group-MUBIG, School sof Nursing & Health Studies, University of Missouri- Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Sarah L Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, 64108, USA
| | - Mark L Johnson
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, 64108, USA
| | - Katharina Jähn
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, 64108, USA
| | - Lynda F Bonewald
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, 64108, USA
| | - Marco Brotto
- Muscle Biology Research Group-MUBIG, School sof Nursing & Health Studies, University of Missouri- Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
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41
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Jähn K, Kelkar S, Zhao H, Xie Y, Tiede-Lewis LM, Dusevich V, Dallas SL, Bonewald LF. Osteocytes Acidify Their Microenvironment in Response to PTHrP In Vitro and in Lactating Mice In Vivo. J Bone Miner Res 2017; 32:1761-1772. [PMID: 28470757 PMCID: PMC5550338 DOI: 10.1002/jbmr.3167] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 04/04/2017] [Accepted: 05/01/2017] [Indexed: 11/10/2022]
Abstract
Osteocytes appear to mobilize calcium within minutes in response to PTH injections; we have previously shown that osteocytes remove their perilacunar matrix during lactation through activation of the PTH type 1 receptor. Mechanisms utilized by osteocytes to mobilize calcium are unknown but we hypothesized that the molecular components may be similar to those used by osteoclasts. Here we show, using IDG-SW3 cells that ATP6V0D2, an essential component of vacuolar ATPase in osteoclasts, and other genes associated with osteoclastic bone resorption, increase with osteoblast to osteocyte differentiation. Furthermore, PTHrP increases ATP6V0D2 expression and induces proton generation by primary osteocytes, which is blocked by bafilomycin, a vacuolar ATPase inhibitor. These in vitro proton measurements raised the question of osteocyte viability in an acidic environment. Interestingly, osteocytes, showed enhanced viability at pH as low as 5 compared to osteoblasts and fibroblasts in vitro. To study in vivo acidification by osteocytes, virgin and lactating CD1 mice on a low calcium diet were injected with the pH indicator dye, acridine orange, and their osteocyte lacuno-canalicular system imaged by confocal microscopy. Lower pH was observed in lactating compared to virgin animals. In addition, a novel transgenic mouse line with a topaz variant of green fluorescent protein (GFPtpz)-tagged collagen α2(I) chain was used. Instead of the expected reduction in GFP-fluorescence only in the perilacunar matrix, reduced fluorescence was observed in the entire bone matrix of lactating mice. Based on our experiments showing quenching of GFP in vitro, we propose that the observed reduction in GFP fluorescence in lactating mice is due to quenching of GFP by the acidic pH generated by osteocytes. Together these findings provide novel mechanistic insight into how osteocytes remove calcium from their perilacunar/pericanalicular matrices through active acidification of their microenvironment and show that osteocytes, like osteoclasts, are resistant to the negative effects of acid on viability. © 2017 American Society for Bone and Mineral Research.
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Affiliation(s)
- Katharina Jähn
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Shilpa Kelkar
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Hong Zhao
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Yixia Xie
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - LeAnn M Tiede-Lewis
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Vladimir Dusevich
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Sarah L Dallas
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Lynda F Bonewald
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
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42
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Qin Y, Peng Y, Zhao W, Pan J, Ksiezak-Reding H, Cardozo C, Wu Y, Divieti Pajevic P, Bonewald LF, Bauman WA, Qin W. Myostatin inhibits osteoblastic differentiation by suppressing osteocyte-derived exosomal microRNA-218: A novel mechanism in muscle-bone communication. J Biol Chem 2017; 292:11021-11033. [PMID: 28465350 DOI: 10.1074/jbc.m116.770941] [Citation(s) in RCA: 173] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 04/26/2017] [Indexed: 12/25/2022] Open
Abstract
Muscle and bone are closely associated in both anatomy and function, but the mechanisms that coordinate their synergistic action remain poorly defined. Myostatin, a myokine secreted by muscles, has been shown to inhibit muscle growth, and the disruption of the myostatin gene has been reported to cause muscle hypertrophy and increase bone mass. Extracellular vesicle-exosomes that carry microRNA (miRNA), mRNA, and proteins are known to perform an important role in cell-cell communication. We hypothesized that myostatin may play a crucial role in muscle-bone interactions and may promote direct effects on osteocytes and on osteocyte-derived exosomal miRNAs, thereby indirectly influencing the function of other bone cells. We report herein that myostatin promotes expression of several bone regulators such as sclerostin (SOST), DKK1, and RANKL in cultured osteocytic (Ocy454) cells, concomitant with the suppression of miR-218 in both parent Ocy454 cells and derived exosomes. Exosomes produced by Ocy454 cells that had been pretreated with myostatin could be taken up by osteoblastic MC3T3 cells, resulting in a marked reduction of Runx2, a key regulator of osteoblastic differentiation, and in decreased osteoblastic differentiation via the down-regulation of the Wnt signaling pathway. Importantly, the inhibitory effect of myostatin-modified osteocytic exosomes on osteoblast differentiation is completely reversed by expression of exogenous miR-218, through a mechanism involving miR-218-mediated inhibition of SOST. Together, our findings indicate that myostatin directly influences osteocyte function and thereby inhibits osteoblastic differentiation, at least in part, through the suppression of osteocyte-derived exosomal miR-218, suggesting a novel mechanism in muscle-bone communication.
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Affiliation(s)
- Yiwen Qin
- From the National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468
| | - Yuanzhen Peng
- From the National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468
| | - Wei Zhao
- From the National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468
| | - Jianping Pan
- From the National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468
| | | | - Christopher Cardozo
- From the National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468.,the Departments of Medicine.,Rehabilitation Medicine, and
| | - Yingjie Wu
- the Departments of Medicine.,Institute of Gene Engineering Animal Models for Human Diseases, Dalian Medical University, Dalian 116044, China
| | - Paola Divieti Pajevic
- the Department of Molecular and Cell Biology, Boston University, Boston, Massachusetts 02215, and
| | - Lynda F Bonewald
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - William A Bauman
- From the National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468.,the Departments of Medicine.,Rehabilitation Medicine, and
| | - Weiping Qin
- From the National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468, .,the Departments of Medicine
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43
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Abstract
When normal physiologic functions go awry, disorders and disease occur. This is universal; even for the osteocyte, a cell embedded within the mineralized matrix of bone. It was once thought that this cell was simply a placeholder in bone. Within the last decade, the number of studies of osteocytes has increased dramatically, leading to the discovery of novel functions of these cells. With the discovery of novel physiologic functions came the discoveries of how these cells can also be responsible for not only bone diseases and disorders, but also those of the kidney, heart, and potentially muscle.
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Affiliation(s)
- Lynda F Bonewald
- Indiana Center for Musculoskeletal Health, VanNuys Medical Science Building, MS 5055, 635 Barnhill Drive, Indianapolis, IN 46202, USA; Department of Anatomy and Cell Biology, VanNuys Medical Science Building, MS 5035, Indianapolis, IN 46202, USA; Department of Orthopaedic Surgery, 1120 West Michigan Street, Suite 600, Indianapolis, IN 46202, USA.
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44
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Abstract
Odontoblasts in dentin and osteocytes in bone contain dendritic processes. To test if their dendrites share a common feature, we compared their cellular morphology as visualized using scanning electron microscopy. Analysis of our data showed that both cells share an identical dendritic canalicular system and express extensive processes forming a complex network within the mineralized matrix. Because dentin matrix protein 1 (DMP1), an extracellular matrix protein, is highly expressed in both types of cells, we next tested, using a transgenic approach, whether a 9.6-kb Dmp1 promoter-4-kb 1st intron would be able to target Cre cDNA in these cells for expression/deletion of other genes in odontoblasts and osteocytes. We determined the specificity and efficiency of Cre activity by crossing Dmp1-Cre mice with ROSA26 reporter mice. Results showed that odontoblasts and osteocytes were specifically targeted, suggesting that this animal model will be useful for the preferential study of gene functions in both types of cells.
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Affiliation(s)
- Y Lu
- Department of Oral Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO 64108, USA
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45
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Farr JN, Fraser DG, Wang H, Jaehn K, Ogrodnik MB, Weivoda MM, Drake MT, Tchkonia T, LeBrasseur NK, Kirkland JL, Bonewald LF, Pignolo RJ, Monroe DG, Khosla S. Identification of Senescent Cells in the Bone Microenvironment. J Bone Miner Res 2016; 31:1920-1929. [PMID: 27341653 PMCID: PMC5289710 DOI: 10.1002/jbmr.2892] [Citation(s) in RCA: 306] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Revised: 06/04/2016] [Accepted: 06/20/2016] [Indexed: 12/27/2022]
Abstract
Cellular senescence is a fundamental mechanism by which cells remain metabolically active yet cease dividing and undergo distinct phenotypic alterations, including upregulation of p16Ink4a , profound secretome changes, telomere shortening, and decondensation of pericentromeric satellite DNA. Because senescent cells accumulate in multiple tissues with aging, these cells and the dysfunctional factors they secrete, termed the senescence-associated secretory phenotype (SASP), are increasingly recognized as promising therapeutic targets to prevent age-related degenerative pathologies, including osteoporosis. However, the cell type(s) within the bone microenvironment that undergoes senescence with aging in vivo has remained poorly understood, largely because previous studies have focused on senescence in cultured cells. Thus in young (age 6 months) and old (age 24 months) mice, we measured senescence and SASP markers in vivo in highly enriched cell populations, all rapidly isolated from bone/marrow without in vitro culture. In both females and males, p16Ink4a expression by real-time quantitative polymerase chain reaction (rt-qPCR) was significantly higher with aging in B cells, T cells, myeloid cells, osteoblast progenitors, osteoblasts, and osteocytes. Further, in vivo quantification of senescence-associated distension of satellites (SADS), ie, large-scale unraveling of pericentromeric satellite DNA, revealed significantly more senescent osteocytes in old compared with young bone cortices (11% versus 2%, p < 0.001). In addition, primary osteocytes from old mice had sixfold more (p < 0.001) telomere dysfunction-induced foci (TIFs) than osteocytes from young mice. Corresponding with the age-associated accumulation of senescent osteocytes was significantly higher expression of multiple SASP markers in osteocytes from old versus young mice, several of which also showed dramatic age-associated upregulation in myeloid cells. These data show that with aging, a subset of cells of various lineages within the bone microenvironment become senescent, although senescent myeloid cells and senescent osteocytes predominantly develop the SASP. Given the critical roles of osteocytes in orchestrating bone remodeling, our findings suggest that senescent osteocytes and their SASP may contribute to age-related bone loss. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- Joshua N Farr
- Robert and Arlene Kogod Center on Aging and Endocrine Research Unit, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Daniel G Fraser
- Robert and Arlene Kogod Center on Aging and Endocrine Research Unit, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Haitao Wang
- Departments of Orthopaedic Surgery and Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Katharina Jaehn
- Department of Oral Biology, University of Missouri-Kansas City, School of Dentistry, Kansas City, MO, USA
| | - Mikolaj B Ogrodnik
- Robert and Arlene Kogod Center on Aging and Endocrine Research Unit, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Megan M Weivoda
- Robert and Arlene Kogod Center on Aging and Endocrine Research Unit, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Matthew T Drake
- Robert and Arlene Kogod Center on Aging and Endocrine Research Unit, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Tamara Tchkonia
- Robert and Arlene Kogod Center on Aging and Endocrine Research Unit, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Nathan K LeBrasseur
- Robert and Arlene Kogod Center on Aging and Endocrine Research Unit, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - James L Kirkland
- Robert and Arlene Kogod Center on Aging and Endocrine Research Unit, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Lynda F Bonewald
- Department of Oral Biology, University of Missouri-Kansas City, School of Dentistry, Kansas City, MO, USA
| | - Robert J Pignolo
- Departments of Orthopaedic Surgery and Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David G Monroe
- Robert and Arlene Kogod Center on Aging and Endocrine Research Unit, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Sundeep Khosla
- Robert and Arlene Kogod Center on Aging and Endocrine Research Unit, Mayo Clinic College of Medicine, Rochester, MN, USA
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Affiliation(s)
- Craig A. Witz
- Departments of Obstetrics and Gynecology, Cellular and Structural Biology and Internal Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, Texas; Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Mail Code 7836, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900
| | | | | | | | | | - Robert S. Schenken
- Departments of Obstetrics and Gynecology, Cellular and Structural Biology and Internal Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, Texas
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Maurel DB, Duan P, Farr J, Cheng AL, Johnson ML, Bonewald LF. Beta-Catenin Haplo Insufficient Male Mice Do Not Lose Bone in Response to Hindlimb Unloading. PLoS One 2016; 11:e0158381. [PMID: 27410430 PMCID: PMC4943721 DOI: 10.1371/journal.pone.0158381] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 06/15/2016] [Indexed: 11/19/2022] Open
Abstract
As the β-catenin pathway has been shown to be involved in mechanotransduction, we sought to determine if haploinsufficiency would affect skeletal response to unloading. It has previously been shown that deletion of both alleles of β-catenin in bone cells results in a fragile skeleton highly susceptible to fracture, but deletion of one allele using Dmp1-Cre (Ctnnb1+/loxP; Dmp1-Cre, cKO HET) has little effect on the 2 mo old skeleton. We found that under normal housing conditions, trabecular bone volume was significantly less in 5 mo old male cKO HET mice compared to controls (Ctrl/HET:Tb. BV/TV = 13.96±2.71/8.92±0.95%, Tb.N. = 4.88±0.51/3.95±0.44/mm, Tb. Sp. = 0.20±0.02/0.26±0.03mm, a 36%, 19% and 30% change respectively) but not in females suggesting an age and gender related effect. Before performing suspension experiments and to control for the environmental effects, animals with the same tail attachment and housing conditions, but not suspended (NS), were compared to normally housed (NH) animals. Attachment and housing resulted in weight loss in both genders and phenotypes. Cortical bone loss was observed in the cKO HET males (NH/NS, Ct BV/TV: 90.45±0.72/89.12±0.56%) and both diaphyseal (0.19±0.01/0.17±0.01mm) and metaphyseal (0.10±0.01/0.08±0.01mm) thickness, but not in female cKO HET mice suggesting that male cKO HET mice are susceptible to attachment and housing conditions. These results with transgenic mice emphasizes the importance of proper controls when attributing skeletal responses to unloading. With suspension, cKO HET male mice did not lose bone unlike female cKO HET mice that had greater trabecular bone loss than controls (Ctrl 9%:cKO HET 21% decrease Tb. N; Ctrl 12%:cKO HET 27% increase Tb. Sp.). Suspended and non-suspended mice lost weight compared to normally housed animals. Taken together, the data suggest a protective effect of β-catenin against the effects of stress in males and partial protection against unloading in females.
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Affiliation(s)
- Delphine B. Maurel
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States of America
| | - Peipei Duan
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States of America
| | - Joshua Farr
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States of America
| | - An-Lin Cheng
- School of Nursing and Health Studies, University of Missouri-Kansas City, Kansas City, MO, United States of America
| | - Mark L. Johnson
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States of America
| | - Lynda F. Bonewald
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States of America
- * E-mail:
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Duan P, Bonewald LF. The role of the wnt/β-catenin signaling pathway in formation and maintenance of bone and teeth. Int J Biochem Cell Biol 2016; 77:23-29. [PMID: 27210503 DOI: 10.1016/j.biocel.2016.05.015] [Citation(s) in RCA: 228] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 02/05/2023]
Abstract
The Wnt signaling pathway is known as one of the important molecular cascades that regulate cell fate throughout lifespan. The Wnt signaling pathway is further separated into the canonical signaling pathway that depends on the function of β-catenin (Wnt/β-catenin pathway) and the noncanonical pathways that operate independently of β-catenin (planar cell polarity pathway and Wnt/Ca(2+) pathway). The Wnt/β-catenin signaling pathway is complex and consists of numerous receptors, inhibitors, activators, modulators, phosphatases, kinases and other components. However, there is one central, critical molecule to this pathway, β-catenin. While there are at least 3 receptors, LRP 4, 5 and 6, and over twenty activators known as the wnts, and several inhibitors such as sclerostin, dickkopf and secreted frizzled-related protein, these all target β-catenin. These regulators/modulators function to target β-catenin either to the proteasome for degradation or to the nucleus to regulate gene expression. Therefore, the interaction of β-catenin with different factors and Wnt/β-catenin signaling pathway will be the subject of this review with a focus on how this pathway relates to and functions in the formation and maintenance of bone and teeth based on mainly basic and pre-clinical research. Also in this review, the role of this pathway in osteocytes, bone cells embedded in the mineralized matrix, is covered in depth. This pathway is not only important in mineralized tissue growth and development, but for modulation of the skeleton in response to loading and unloading and the viability and health of the adult and aging skeleton.
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Affiliation(s)
- Peipei Duan
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - L F Bonewald
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA.
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Wacker MJ, Touchberry CD, Silswal N, Brotto L, Elmore CJ, Bonewald LF, Andresen J, Brotto M. Skeletal Muscle, but not Cardiovascular Function, Is Altered in a Mouse Model of Autosomal Recessive Hypophosphatemic Rickets. Front Physiol 2016; 7:173. [PMID: 27242547 PMCID: PMC4866514 DOI: 10.3389/fphys.2016.00173] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 04/28/2016] [Indexed: 01/29/2023] Open
Abstract
Autosomal recessive hypophosphatemic rickets (ARHR) is a heritable disorder characterized by hypophosphatemia, osteomalacia, and poor bone development. ARHR results from inactivating mutations in the DMP1 gene with the human phenotype being recapitulated in the Dmp1 null mouse model which displays elevated plasma fibroblast growth factor 23. While the bone phenotype has been well-characterized, it is not known what effects ARHR may also have on skeletal, cardiac, or vascular smooth muscle function, which is critical to understand in order to treat patients suffering from this condition. In this study, the extensor digitorum longus (EDL-fast-twitch muscle), soleus (SOL–slow-twitch muscle), heart, and aorta were removed from Dmp1 null mice and ex-vivo functional tests were simultaneously performed in collaboration by three different laboratories. Dmp1 null EDL and SOL muscles produced less force than wildtype muscles after normalization for physiological cross sectional area of the muscles. Both EDL and SOL muscles from Dmp1 null mice also produced less force after the addition of caffeine (which releases calcium from the sarcoplasmic reticulum) which may indicate problems in excitation contraction coupling in these mice. While the body weights of the Dmp1 null were smaller than wildtype, the heart weight to body weight ratio was higher. However, there were no differences in pathological hypertrophic gene expression compared to wildtype and maximal force of contraction was not different indicating that there may not be cardiac pathology under the tested conditions. We did observe a decrease in the rate of force development generated by cardiac muscle in the Dmp1 null which may be related to some of the deficits observed in skeletal muscle. There were no differences observed in aortic contractions induced by PGF2α or 5-HT or in endothelium-mediated acetylcholine-induced relaxations or endothelium-independent sodium nitroprusside-induced relaxations. In summary, these results indicate that there are deficiencies in both fast twitch and slow twitch muscle fiber type contractions in this model of ARHR, while there was less of a phenotype observed in cardiac muscle, and no differences observed in aortic function. These results may help explain skeletal muscle weakness reported by some patients with osteomalacia and need to be further investigated.
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Affiliation(s)
- Michael J Wacker
- Muscle Biology Research Group, School of Medicine, University of Missouri-Kansas City Kansas City, MO, USA
| | | | - Neerupma Silswal
- Muscle Biology Research Group, School of Medicine, University of Missouri-Kansas City Kansas City, MO, USA
| | - Leticia Brotto
- Bone-Muscle Collaborative Science, College of Nursing and Health Innovation, University of Texas at Arlington Arlington, TX, USA
| | - Chris J Elmore
- Muscle Biology Research Group, School of Medicine, University of Missouri-Kansas City Kansas City, MO, USA
| | - Lynda F Bonewald
- Bone Biology Research Group, School of Dentistry, University of Missouri-Kansas City Kansas City, MO, USA
| | - Jon Andresen
- Muscle Biology Research Group, School of Medicine, University of Missouri-Kansas City Kansas City, MO, USA
| | - Marco Brotto
- Bone-Muscle Collaborative Science, College of Nursing and Health Innovation, University of Texas at Arlington Arlington, TX, USA
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Abstract
Cementum is a mineralized tissue covering the tooth root that functions in tooth attachment and posteruptive adjustment of tooth position. During formation of the apically located cellular cementum, some cementoblasts become embedded in the cementoid matrix and become cementocytes. As apparently terminally differentiated cells embedded in a mineralized extracellular matrix, cementocytes are part of a select group of specialized cells, also including osteocytes, hypertrophic chondrocytes, and odontoblasts. The differentiation and potential function(s) of cementocytes are virtually unknown, and the question may be posed whether the cementocyte is a dynamic actor in cementum in comparable fashion with the osteocyte in the skeleton, responding to changing tooth functions and endocrine signals and actively directing local cementum metabolism. This review summarizes the literature with regard to cementocytes, comparing them to their closest "cousins," the osteocytes, where insights gained from osteocyte studies serve to inform the critical examination of cementocytes. The review identifies important unanswered questions about these cells regarding their origins, differentiation, morphology and lacuno-canalicular system, selective markers, and potential functions.
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Affiliation(s)
- N Zhao
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA Department of Orthodontics, Shanghai Key Laboratory of Stomatology, Shanghai No. 9 Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - B L Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - L F Bonewald
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
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