1
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Vahidi G, Boone C, Hoffman F, Heveran C. Aging decreases osteocyte peri-lacunar-canalicular system turnover in female C57BL/6JN mice. Bone 2024; 186:117163. [PMID: 38857854 PMCID: PMC11227388 DOI: 10.1016/j.bone.2024.117163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 06/06/2024] [Accepted: 06/07/2024] [Indexed: 06/12/2024]
Abstract
Osteocytes engage in bone resorption and mineralization surrounding their expansive lacunar-canalicular system (LCS) through peri-LCS turnover. However, fundamental questions persist about where, when, and how often osteocytes engage in peri-LCS turnover and how these processes change with aging. Furthermore, whether peri-LCS turnover is associated with natural variation in cortical tissue strain remains unexplored. To address these questions, we utilized confocal scanning microscopy, immunohistochemistry, and scanning electron microscopy to characterize osteocyte peri-LCS turnover in the cortical (mid-diaphysis) and cancellous (metaphysis) regions of femurs from young adult (5 mo) and early-old-age (22 mo) female C57BL/6JN mice. LCS bone mineralization was measured by the presence of perilacunar fluorochrome labels. LCS bone resorption was measured by immunohistochemical marker of bone resorption. The dynamics of peri-LCS turnover were estimated from serial fluorochrome labeling, where each mouse was administered two labels between 2 and 16 days before euthanasia. Osteocyte participation in mineralizing their surroundings is highly abundant in both cortical and cancellous bone of young adult mice but significantly decreases with aging. LCS bone resorption also decreases with aging. Aging has a greater impact on peri-LCS turnover dynamics in cancellous bone than in cortical bone. Lacunae with recent peri-LCS turnover are larger in both age groups. While peri-LCS turnover is associated with variation in tissue strain between cortical quadrants and intracortical location for 22 mo mice, these associations were not seen for 5 mo mice. The impact of aging on decreasing peri-LCS turnover may have significant implications for bone quality and mechanosensation.
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Affiliation(s)
- Ghazal Vahidi
- Department of Mechanical & Industrial Engineering, Montana State University, Bozeman, MT, USA
| | - Connor Boone
- Department of Mechanical & Industrial Engineering, Montana State University, Bozeman, MT, USA
| | - Fawn Hoffman
- Department of Biomedical Sciences, College of Idaho, Caldwell, ID, USA
| | - Chelsea Heveran
- Department of Mechanical & Industrial Engineering, Montana State University, Bozeman, MT, USA.
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2
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Hua R, Truong VA, Fajardo RJ, Guda T, Gu S, Jiang JX. Connexin hemichannels drive lactation-induced osteocyte acidification and perilacunar-canalicular remodeling. Cell Rep 2024; 43:114363. [PMID: 38935505 DOI: 10.1016/j.celrep.2024.114363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 04/30/2024] [Accepted: 05/31/2024] [Indexed: 06/29/2024] Open
Abstract
The maternal skeleton experiences significant bone loss during lactation, followed by rapid restoration post weaning. Parathyroid-related protein (PTHrP)-induced acidification of the perilacunar matrix by osteocytes is crucial in this process, yet its mechanism remains unclear. Here, we identify Cx43 hemichannels (HCs) as key mediators of osteocyte acidification and perilacunar-canalicular remodeling (PLR). Utilizing transgenic mouse models expressing dominant-negative Cx43 mutants, we show that mice with impaired Cx43 HCs exhibit attenuated lactation-induced responses compared to wild-type and only gap junction-impaired groups, including lacunar enlargement, upregulation of PLR genes, and bone loss with compromised mechanical properties. Furthermore, inhibition of HCs by a Cx43 antibody blunts PTHrP-induced calcium influx and protein kinase A activation, followed by impaired osteocyte acidification. Additionally, impeded HCs suppress bone recovery during the post-lactation period. Our findings highlight the pivotal role of Cx43 HCs in orchestrating dynamic bone changes during lactation and recovery by regulating acidification and remodeling enzyme expression.
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Affiliation(s)
- Rui Hua
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Vu A Truong
- School of Osteopathic Medicine, University of the Incarnate Word, San Antonio, TX 78209, USA
| | - Roberto J Fajardo
- School of Osteopathic Medicine, University of the Incarnate Word, San Antonio, TX 78209, USA
| | - Teja Guda
- Department of Biomedical Engineering and Chemical Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Sumin Gu
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
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3
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Yee CS, Meliadis C, Kaya S, Chang W, Alliston T. The osteocytic actions of glucocorticoids on bone mass, mechanical properties, or perilacunar remodeling outcomes are not rescued by PTH(1-34). Front Endocrinol (Lausanne) 2024; 15:1342938. [PMID: 39092287 PMCID: PMC11291448 DOI: 10.3389/fendo.2024.1342938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 06/26/2024] [Indexed: 08/04/2024] Open
Abstract
Glucocorticoids (GC) and parathyroid hormone (PTH) are widely used therapeutic endocrine hormones where their effects on bone and joint arise from actions on multiple skeletal cell types. In osteocytes, GC and PTH exert opposing effects on perilacunar canalicular remodeling (PLR). Suppressed PLR can impair bone quality and joint homeostasis, including in GC-induced osteonecrosis. However, combined effects of GC and PTH on PLR are unknown. Given the untapped potential to target osteocytes to improve skeletal health, this study sought to test the feasibility of therapeutically mitigating PLR suppression. Focusing on subchondral bone and joint homeostasis, we hypothesize that PTH(1-34), a PLR agonist, could rescue GC-suppressed PLR. The skeletal effects of GC and PTH(1-34), alone or combined, were examined in male and female mice by micro-computed tomography, mechanical testing, histology, and gene expression analysis. For each outcome, females were more responsive to GC and PTH(1-34) than males. GC and PTH(1-34) exerted regional differences, with GC increasing trabecular bone volume but reducing cortical bone thickness, stiffness, and ultimate force. Despite PTH(1-34)'s anabolic effects on trabecular bone, it did not rescue GC's catabolic effects on cortical bone. Likewise, cartilage integrity and subchondral bone apoptosis, tartrate-resistant acid phosphatase (TRAP) activity, and osteocyte lacunocanalicular networks showed no evidence that PTH(1-34) could offset GC-dependent effects. Rather, GC and PTH(1-34) each increased cortical bone gene expression implicated in bone resorption by osteoclasts and osteocytes, including Acp5, Mmp13, Atp6v0d2, Ctsk, differences maintained when GC and PTH(1-34) were combined. Since PTH(1-34) is insufficient to rescue GC's effects on young female mouse bone, future studies are needed to determine if osteocyte PLR suppression, due to GC, aging, or other factors, can be offset by a PLR agonist.
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Affiliation(s)
- Cristal S. Yee
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Christoforos Meliadis
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Serra Kaya
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Wenhan Chang
- Endocrine Research Unit, San Francisco Veterans Affairs Medical Center, University of California, San Francisco, CA, United States
| | - Tamara Alliston
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, United States
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4
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Jagga S, Hughes A, Manoochehri Arash N, Sorsby M, Brooks DJ, Divieti Pajevic P, Liu ES. NFATc1 Is Required for Vitamin D- and Phosphate-Mediated Regulation of Osteocyte Lacuno-Canalicular Remodeling. Endocrinology 2024; 165:bqae087. [PMID: 39024412 DOI: 10.1210/endocr/bqae087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 07/11/2024] [Accepted: 07/15/2024] [Indexed: 07/20/2024]
Abstract
Osteocytes are embedded in lacunae and connected by canaliculi (lacuno-canalicular network, LCN). Bones from mice with X-linked hypophosphatemia (Hyp), which have impaired production of 1,25 dihydroxyvitamin D (1,25D) and hypophosphatemia, have abnormal LCN structure that is improved by treatment with 1,25D or an anti-FGF23 targeting antibody, supporting roles for 1,25D and phosphate in regulating LCN remodeling. Bones from mice lacking the vitamin D receptor (VDR) in osteocytes (Vdrf/f;Dmp1Cre+) and mice lacking the sodium phosphate transporter 2a (Npt2aKO), which have low serum phosphate with high serum 1,25D, have impaired LCN organization, demonstrating that osteocyte-specific actions of 1,25D and hypophosphatemia regulate LCN remodeling. In osteoclasts, nuclear factor of activated T cells cytoplasmic 1 (NFATc1) is critical for stimulating bone resorption. Since osteocytes also resorb matrix, we hypothesize that NFATc1 plays a role in 1,25D and phosphate-mediated LCN remodeling. Consistent with this, 1,25D and phosphate suppress Nfatc1 mRNA expression in IDG-SW3 osteocytes, and knockdown of Nfatc1 expression in IDG-SW3 cells blocks 1,25D- and phosphate-mediated suppression of matrix resorption gene expression and 1,25D- and phosphate-mediated suppression of RANKL-induced acidification of the osteocyte microenvironment. To determine the role of NFATc1 in 1,25D- and phosphate-mediated LCN remodeling in vivo, histomorphometric analyses of tibiae from mice lacking osteocyte-specific Nfatc1 in Vdrf/f;Dmp1Cre+ and Npt2aKO mice were performed, demonstrating that bones from these mice have decreased lacunar size and expression of matrix resorption genes, and improved canalicular structure compared to Vdrf/f;Dmp1Cre+ and Npt2aKO control. This study demonstrates that NFATc1 is necessary for 1,25D- and phosphate-mediated regulation of LCN remodeling.
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Affiliation(s)
- Supriya Jagga
- Division of Endocrinology, Diabetes, and Hypertension, Brigham and Women's Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Ashleigh Hughes
- Division of Endocrinology, Diabetes, and Hypertension, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Niusha Manoochehri Arash
- Division of Endocrinology, Diabetes, and Hypertension, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Melissa Sorsby
- Division of Endocrinology, Diabetes, and Hypertension, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Daniel J Brooks
- Harvard Medical School, Boston, MA 02115, USA
- Endocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Paola Divieti Pajevic
- Department of Translational Dental Medicine, Boston University School of Dental Medicine, Boston, MA 02118, USA
| | - Eva S Liu
- Division of Endocrinology, Diabetes, and Hypertension, Brigham and Women's Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
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Sieverts M, Yee C, Nemani M, Parkinson DY, Alliston T, Acevedo C. Spatial control of perilacunar canalicular remodeling during lactation. Sci Rep 2024; 14:14655. [PMID: 38918485 PMCID: PMC11199490 DOI: 10.1038/s41598-024-63645-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 05/30/2024] [Indexed: 06/27/2024] Open
Abstract
Osteocytes locally remodel their surrounding tissue through perilacunar canalicular remodeling (PLR). During lactation, osteocytes remove minerals to satisfy the metabolic demand, resulting in increased lacunar volume, quantifiable with synchrotron X-ray radiation micro-tomography (SRµCT). Although the effects of lactation on PLR are well-studied, it remains unclear whether PLR occurs uniformly throughout the bone and what mechanisms prevent PLR from undermining bone quality. We used SRµCT imaging to conduct an in-depth spatial analysis of the impact of lactation and osteocyte-intrinsic MMP13 deletion on PLR in murine bone. We found larger lacunae undergoing PLR are located near canals in the mid-cortex or endosteum. We show lactation-induced hypomineralization occurs 14 µm away from lacunar edges, past a hypermineralized barrier. Our findings reveal that osteocyte-intrinsic MMP13 is crucial for lactation-induced PLR near lacunae in the mid-cortex but not for whole-bone resorption. This research highlights the spatial control of PLR on mineral distribution during lactation.
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Affiliation(s)
- Michael Sieverts
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, 84112, USA
| | - Cristal Yee
- Department of Orthopedic Surgery, University of California, San Francisco, CA, 94131, USA
| | - Minali Nemani
- Department of Orthopedic Surgery, University of California, San Francisco, CA, 94131, USA
| | | | - Tamara Alliston
- Department of Orthopedic Surgery, University of California, San Francisco, CA, 94131, USA
| | - Claire Acevedo
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, 84112, USA.
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, 84112, USA.
- Department of Mechanical and Aerospace Engineering, University of California San Diego, San Diego, CA, 92161, USA.
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6
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Galiana-Melendez F, Huot JR. The Impact of Non-bone Metastatic Cancer on Musculoskeletal Health. Curr Osteoporos Rep 2024; 22:318-329. [PMID: 38649653 DOI: 10.1007/s11914-024-00872-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/14/2024] [Indexed: 04/25/2024]
Abstract
PURPOSE OF REVIEW The purpose of this review is to discuss the musculoskeletal consequences of cancer, including those that occur in the absence of bone metastases. RECENT FINDINGS Cancer patients frequently develop cachexia, a debilitating condition reflected by weight loss and skeletal muscle wasting. The negative effects that tumors exert on bone health represents a growing interest amongst cachexia researchers. Recent clinical and pre-clinical evidence demonstrates cancer-induced bone loss, even in the absence of skeletal metastases. Together with muscle wasting, losses in bone demonstrates the impact of cancer on the musculoskeletal system. Identifying therapeutic targets that comprehensively protect musculoskeletal health is essential to improve the quality of life in cancer patients and survivors. IL-6, RANKL, PTHrP, sclerostin, and TGF-β superfamily members represent potential targets to counteract cachexia. However, more research is needed to determine the efficacy of these targets in protecting both skeletal muscle and bone.
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Affiliation(s)
| | - Joshua R Huot
- Department of Anatomy, Cell Biology & Physiology, Indianapolis, IN, 46202, USA.
- Indiana Center for Musculoskeletal Health, 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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7
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Cheng K, Gao S, Mei Y, Zhou D, Song C, Guo D, Hou Y, Liu Z. The bone nonunion microenvironment: A place where osteogenesis struggles with osteoclastic capacity. Heliyon 2024; 10:e31314. [PMID: 38813209 PMCID: PMC11133820 DOI: 10.1016/j.heliyon.2024.e31314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 05/31/2024] Open
Abstract
Bone nonunion is a common and serious orthopedic disorder, the occurrence of which is associated with a disruption of the dynamic balance between osteoblasts and osteoclasts during bone repair. However, the critical molecular mechanisms affecting this homeostasis are not well understood, and it is essential to investigate the specific components of this mechanism and to restore the balance between osteoblasts and osteoclasts to promote bone repair. First, we defined this complex local environmental factor as the "bone nonunion microenvironment" and identified the importance of the "struggle" between osteoblasts and osteoclasts, which is the most essential element in determining the process of repair. On this basis, we also explored the cellular factors that influence osteogenesis and the molecular signals that influence the balance between osteoclast and osteoblasts, which are important for restoring homeostasis. Further, we explored other factors involved in osteogenesis, such as the biomechanical environment, the nutritional environment, the acid-base environment, and the temperature environment, which are important players in osteogenesis. In conclusion, we found that the balance between osteoblasts and osteoclasts is the essence of bone healing, which is based on the "bone nonunion microenvironment". Therefore, investigating the role of the bone nonunion microenvironment in the system of osteoblast-osteoclast "struggle" provides an important basis for further understanding of the mechanism of nonunion and the development of new therapeutic approaches.
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Affiliation(s)
- Kang Cheng
- Department of Orthopedics and Traumatology, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, China
| | - Silong Gao
- Department of Orthopedics and Traumatology, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, China
| | - Yongliang Mei
- Department of Orthopedics and Traumatology, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, China
| | - Daqian Zhou
- Department of Orthopedics and Traumatology, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, China
| | - Chao Song
- Department of Orthopedics and Traumatology, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, China
| | - Daru Guo
- Department of Orthopedics and Traumatology, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, China
| | - Yunqing Hou
- Department of Medical Imaging, Luzhou Longmatan District People's Hospital, Luzhou, China
| | - Zongchao Liu
- Department of Orthopedics and Traumatology, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, China
- Department of Medical Imaging, Luzhou Longmatan District People's Hospital, Luzhou, China
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8
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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] [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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9
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Nakanishi T, Yamazaki M, Tachikawa K, Ueta A, Kawai M, Ozono K, Michigami T. Complex intrinsic abnormalities in osteoblast lineage cells of X-linked hypophosphatemia: Analysis of human iPS cell models generated by CRISPR/Cas9-mediated gene ablation. Bone 2024; 181:117044. [PMID: 38331306 DOI: 10.1016/j.bone.2024.117044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/04/2024] [Accepted: 02/05/2024] [Indexed: 02/10/2024]
Abstract
X-linked hypophosphatemia (XLH) is caused by inactivating variants of the phosphate regulating endopeptidase homolog X-linked (PHEX) gene. Although the overproduction of fibroblast growth factor 23 (FGF23) is responsible for hypophosphatemia and impaired vitamin D metabolism, the pathogenesis of XLH remains unclear. We herein generated PHEX-knockout (KO) human induced pluripotent stem (iPS) cells by applying CRISPR/Cas9-mediated gene ablation to an iPS clone derived from a healthy male, and analyzed PHEX-KO iPS cells with deletions extending from exons 1 to 3 and frameshifts by inducing them to differentiate into the osteoblast lineage. We confirmed the increased production of FGF23 in osteoblast lineage cells differentiated from PHEX-KO iPS cells. In vitro mineralization was enhanced in osteoblast lineage cells from PHEX-KO iPS cells than in those from isogenic control iPS cells, which reminded us of high bone mineral density and enthesopathy in patients with XLH. The extracellular level of pyrophosphate (PPi), an inhibitor of mineralization, was elevated, and this increase appeared to be partly due to the reduced activity of tissue non-specific alkaline phosphatase (TNSALP). Osteoblast lineage cells derived from PHEX-KO iPS cells also showed the increased expression of multiple molecules such as dentine matrix protein 1, osteopontin, RUNX2, FGF receptor 1 and early growth response 1. This gene dysregulation was similar to that in the osteoblasts/osteocytes of Phex-deficient Hyp mice, suggesting that common pathogenic mechanisms are shared between human XLH and Hyp mice. Moreover, we found that the phosphorylation of CREB was markedly enhanced in osteoblast lineage cells derived from PHEX-KO iPS cells, which appeared to be associated with the up-regulation of the parathyroid hormone related protein gene. PHEX deficiency also affected the response of the ALPL gene encoding TNSALP to extracellular Pi. Collectively, these results indicate that complex intrinsic abnormalities in osteoblasts/osteocytes underlie the pathogenesis of human XLH.
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Affiliation(s)
- Tatsuro Nakanishi
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, Izumi, Osaka 594-1101, Japan; Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Miwa Yamazaki
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, Izumi, Osaka 594-1101, Japan
| | - Kanako Tachikawa
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, Izumi, Osaka 594-1101, Japan
| | - Ayu Ueta
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, Izumi, Osaka 594-1101, Japan; 1st Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Masanobu Kawai
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, Izumi, Osaka 594-1101, Japan
| | | | - Toshimi Michigami
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, Izumi, Osaka 594-1101, Japan.
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10
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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 : THE PREPRINT SERVER FOR BIOLOGY 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] [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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11
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Zhang J, Bai H, Bai M, Wang X, Li Z, Xue H, Wang J, Cui Y, Wang H, Wang Y, Zhou R, Zhu X, Xu M, Zhao X, Liu H. Bisphosphonate-incorporated coatings for orthopedic implants functionalization. Mater Today Bio 2023; 22:100737. [PMID: 37576870 PMCID: PMC10413202 DOI: 10.1016/j.mtbio.2023.100737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/06/2023] [Accepted: 07/19/2023] [Indexed: 08/15/2023] Open
Abstract
Bisphosphonates (BPs), the stable analogs of pyrophosphate, are well-known inhibitors of osteoclastogenesis to prevent osteoporotic bone loss and improve implant osseointegration in patients suffering from osteoporosis. Compared to systemic administration, BPs-incorporated coatings enable the direct delivery of BPs to the local area, which will precisely enhance osseointegration and bone repair without the systemic side effects. However, an elaborate and comprehensive review of BP coatings of implants is lacking. Herein, the cellular level (e.g., osteoclasts, osteocytes, osteoblasts, osteoclast precursors, and bone mesenchymal stem cells) and molecular biological regulatory mechanism of BPs in regulating bone homeostasis are overviewed systematically. Moreover, the currently available methods (e.g., chemical reaction, porous carriers, and organic material films) of BP coatings construction are outlined and summarized in detail. As one of the key directions, the latest advances of BP-coated implants to enhance bone repair and osseointegration in basic experiments and clinical trials are presented and critically evaluated. Finally, the challenges and prospects of BP coatings are also purposed, and it will open a new chapter in clinical translation for BP-coated implants.
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Affiliation(s)
- Jiaxin Zhang
- Orthopedic Institute of Jilin Province, Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Haotian Bai
- Orthopedic Institute of Jilin Province, Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Miao Bai
- Department of Ocular Fundus Disease, Ophthalmology Center, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Xiaonan Wang
- Orthopedic Institute of Jilin Province, Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - ZuHao Li
- Orthopedic Institute of Jilin Province, Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Haowen Xue
- Orthopedic Institute of Jilin Province, Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Jincheng Wang
- Orthopedic Institute of Jilin Province, Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Yutao Cui
- Orthopedic Institute of Jilin Province, Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Hui Wang
- Orthopedic Institute of Jilin Province, Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Yanbing Wang
- Orthopedic Institute of Jilin Province, Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Rongqi Zhou
- Orthopedic Institute of Jilin Province, Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Xiujie Zhu
- Orthopedic Institute of Jilin Province, Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Mingwei Xu
- Orthopedic Institute of Jilin Province, Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Xin Zhao
- Orthopedic Institute of Jilin Province, Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - He Liu
- Orthopedic Institute of Jilin Province, Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun 130041, PR China
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12
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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] [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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13
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Matthews M, Cook E, Naguib N, Wiesner U, Lewis K. Intravital imaging of osteocyte integrin dynamic with locally injectable fluorescent nanoparticles. Bone 2023:116830. [PMID: 37327917 DOI: 10.1016/j.bone.2023.116830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 06/05/2023] [Accepted: 06/13/2023] [Indexed: 06/18/2023]
Abstract
Osteocytes are the resident mechanosensory cells in bone. They are responsible for skeletal homeostasis and adaptation to mechanical cues. Integrin proteins play a prominent role in osteocyte mechanotransduction, but the details are not well stratified. Intravital imaging with multiphoton microscopy presents an opportunity to study molecular level mechanobiological events in vivo and presents an opportunity to study integrin dynamics in osteocytes. However, fluorescent imaging limitations with respect to excessive optical scattering and low signal to noise ratio caused by mineralized bone matrix make such investigations non-trivial. Here, we demonstrate that ultra-small and bright fluorescent core-shell silica nanoparticles (<7 nm diameter), known as Cornell Prime Dots (C'Dots), are well-suited for the in vivo bone microenvironment and can improve intravital imaging capabilities. We report validation studies for C'Dots as a novel, locally injectable in vivo osteocyte imaging tool for both non-specific cellular uptake and for targeting integrins. The pharmacokinetics of C'Dots reveal distinct sex differences in nanoparticle intracellular dynamics and clearance in osteocytes, which represents a novel topic of study in bone biology. Integrin-targeted C'Dots were used to study osteocyte integrin dynamics. To the best of our knowledge, we report here the first evidence of osteocyte integrin endocytosis and recycling in vivo. Our results provide novel insights in osteocyte biology and will open up new lines of investigation that were previously unavailable in vivo.
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Affiliation(s)
- Melia Matthews
- Department of Biomedical Engineering, Cornell University, 237 Tower Rd, Ithaca 14850, NY, USA
| | - Emily Cook
- Department of Biomedical Engineering, Cornell University, 237 Tower Rd, Ithaca 14850, NY, USA
| | - Nada Naguib
- Department of Biomedical Engineering, Cornell University, 237 Tower Rd, Ithaca 14850, NY, USA
| | - Uli Wiesner
- Department of Materials Science and Engineering, Cornell University, Bard Hall 210, Ithaca 14850, NY, USA
| | - Karl Lewis
- Department of Biomedical Engineering, Cornell University, 237 Tower Rd, Ithaca 14850, NY, USA.
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14
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Sang W, Ural A. Evaluating the Role of Canalicular Morphology and Perilacunar Region Properties on Local Mechanical Environment of Lacunar-Canalicular Network Using Finite Element Modeling. J Biomech Eng 2023; 145:1156059. [PMID: 36629002 DOI: 10.1115/1.4056655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 01/07/2023] [Indexed: 01/12/2023]
Abstract
Physiological and pathological processes such as aging, diseases, treatments, and lactation can alter lacunar-canalicular network (LCN) morphology and perilacunar region properties. These modifications can impact the mechanical environment of osteocytes which in turn can influence osteocyte mechanosensitivity and the remodeling process. In this study, we aim to evaluate how the modifications in the canalicular morphology, lacunar density, and the perilacunar region properties influence the local mechanical environment of LCN and the apparent bone properties using three-dimensional finite element (FE) modeling. The simulation results showed that a 50% reduction in perilacunar elastic modulus led to about 7% decrease in apparent elastic modulus of the bone. The increase in canalicular density, length, and diameter did not influence the strain amplification in the models but they increased the amount of highly strained bone around LCN. Change in lacunar density did not influence the strain amplification and the amount of highly strained regions on LCN surfaces. Reduction in perilacunar elastic modulus increased both the strain amplification and the volume of highly strained tissue around and on the surface of LCN. The FE models of LCN in this study can be utilized to quantify the influence of modifications in canalicular morphology, lacunar density, and perilacunar region properties on the apparent bone properties and the local mechanical environment of LCN. Although this is a numerical study with idealized models, it provides important information on how mechanical environment of osteocytes is influenced by the modifications in LCN morphology and perilacunar region properties due to physiological and pathological processes.
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Affiliation(s)
- Wen Sang
- Department of Mechanical Engineering, Villanova University, 800 Lancaster Avenue, Villanova, PA 19085
| | - Ani Ural
- Department of Mechanical Engineering, Villanova University, 800 Lancaster Avenue, Villanova, PA 19085
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15
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Marahleh A, Kitaura H, Ohori F, Noguchi T, Mizoguchi I. The osteocyte and its osteoclastogenic potential. Front Endocrinol (Lausanne) 2023; 14:1121727. [PMID: 37293482 PMCID: PMC10244721 DOI: 10.3389/fendo.2023.1121727] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 04/07/2023] [Indexed: 06/10/2023] Open
Abstract
The skeleton is an organ of dual functionality; on the one hand, it provides protection and structural competence. On the other hand, it participates extensively in coordinating homeostasis globally given that it is a mineral and hormonal reservoir. Bone is the only tissue in the body that goes through strategically consistent bouts of bone resorption to ensure its integrity and organismal survival in a temporally and spatially coordinated process, known as bone remodeling. Bone remodeling is directly enacted by three skeletal cell types, osteoclasts, osteoblasts, and osteocytes; these cells represent the acting force in a basic multicellular unit and ensure bone health maintenance. The osteocyte is an excellent mechanosensory cell and has been positioned as the choreographer of bone remodeling. It is, therefore, not surprising that a holistic grasp of the osteocyte entity in the bone is warranted. This review discusses osteocytogenesis and associated molecular and morphological changes and describes the osteocytic lacunocanalicular network (LCN) and its organization. We highlight new knowledge obtained from transcriptomic analyses of osteocytes and discuss the regulatory role of osteocytes in promoting osteoclastogenesis with an emphasis on the case of osteoclastogenesis in anosteocytic bones. We arrive at the conclusion that osteocytes exhibit several redundant means through which osteoclast formation can be initiated. However, whether osteocytes are true "orchestrators of bone remodeling" cannot be verified from the animal models used to study osteocyte biology in vivo. Results from studying osteocyte biology using current animal models should come with the caveat that these models are not osteocyte-specific, and conclusions from these studies should be interpreted cautiously.
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Affiliation(s)
- Aseel Marahleh
- Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, Sendai, Japan
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Japan
| | - Hideki Kitaura
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Japan
| | - Fumitoshi Ohori
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Japan
| | - Takahiro Noguchi
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Japan
| | - Itaru Mizoguchi
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Japan
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16
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Shimonty A, Bonewald LF, Pin F. Role of the Osteocyte in Musculoskeletal Disease. Curr Osteoporos Rep 2023; 21:303-310. [PMID: 37084017 DOI: 10.1007/s11914-023-00788-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/12/2023] [Indexed: 04/22/2023]
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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17
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Athonvarangkul D, Wysolmerski JJ. Crosstalk within a brain-breast-bone axis regulates mineral and skeletal metabolism during lactation. Front Physiol 2023; 14:1121579. [PMID: 36875035 PMCID: PMC9979219 DOI: 10.3389/fphys.2023.1121579] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 01/27/2023] [Indexed: 02/18/2023] Open
Abstract
To support the increased calcium demands for milk production during lactation, a dramatic and reversible physiological response occurs to alter bone and mineral metabolism. This coordinated process involves a brain-breast-bone axis that integrates hormonal signals that allow for adequate calcium delivery to milk yet also protects the maternal skeletal from excessive bone loss or decreases in bone quality or function. Here, we review the current knowledge on the crosstalk between the hypothalamus, mammary gland, and skeleton during lactation. We discuss the rare entity of pregnancy and lactation associated osteoporosis and consider how the physiology of bone turnover in lactation may impact the pathophysiology of postmenopausal osteoporosis. Further understanding of the regulators of bone loss during lactation, particularly in humans, may provide insights into new therapies for osteoporosis and other diseases of excess bone loss.
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Affiliation(s)
- Diana Athonvarangkul
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
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18
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Histological Assessment of Endochondral Ossification and Bone Mineralization. ENDOCRINES 2023. [DOI: 10.3390/endocrines4010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Finely tuned cartilage mineralization, endochondral ossification, and normal bone formation are necessary for normal bone growth. Hypertrophic chondrocytes in the epiphyseal cartilage secrete matrix vesicles, which are small extracellular vesicles initiating mineralization, into the intercolumnar septa but not the transverse partitions of the cartilage columns. Bone-specific blood vessels invade the unmineralized transverse septum, exposing the mineralized cartilage cores. Many osteoblast precursors migrate to the cartilage cores, where they synthesize abundant bone matrices, and mineralize them in a process of matrix vesicle-mediated bone mineralization. Matrix vesicle-mediated mineralization concentrates calcium (Ca) and inorganic phosphates (Pi), which are converted into hydroxyapatite crystals. These crystals grow radially and are eventually get out of the vesicles to form spherical mineralized nodules, leading to collagen mineralization. The influx of Ca and Pi into the matrix vesicle is regulated by several enzymes and transporters such as TNAP, ENPP1, PiT1, PHOSPHO1, annexins, and others. Such matrix vesicle-mediated mineralization is regulated by osteoblastic activities, synchronizing the synthesis of organic bone material. However, osteocytes reportedly regulate peripheral mineralization, e.g., osteocytic osteolysis. The interplay between cartilage mineralization and vascular invasion during endochondral ossification, as well as that of osteoblasts and osteocytes for normal mineralization, appears to be crucial for normal bone growth.
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19
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Heveran CM, Boerckel JD. Osteocyte Remodeling of the Lacunar-Canalicular System: What's in a Name? Curr Osteoporos Rep 2023; 21:11-20. [PMID: 36512204 PMCID: PMC11223162 DOI: 10.1007/s11914-022-00766-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/18/2022] [Indexed: 12/15/2022]
Abstract
PURPOSE OF REVIEW Osteocytes directly modify the bone surrounding the expansive lacunar-canalicular system (LCS) through both resorption and deposition. The existence of this phenomenon is now widely accepted, but is referred to as "osteocyte osteolysis," "LCS remodeling," and "perilacunar remodeling," among other names. The uncertainty in naming this physiological process reflects the many persistent questions about why and how osteocytes interact with local bone matrix. The goal of this review is to examine the purpose and nature of LCS remodeling and its impacts on multiscale bone quality. RECENT FINDINGS While LCS remodeling is clearly important for systemic calcium mobilization, this process may have additional potential drivers and may impact the ability of bone to resist fracture. There is abundant evidence that the osteocyte can resorb and replace bone mineral and does so outside of extreme challenges to mineral homeostasis. The impacts of the osteocyte on organic matrix are less certain, especially regarding whether osteocytes produce osteoid. Though multiple lines of evidence point towards osteocyte production of organic matrix, definitive work is needed. Recent high-resolution imaging studies demonstrate that LCS remodeling influences local material properties. The role of LCS remodeling in the maintenance and deterioration of bone matrix quality in aging and disease are active areas of research. In this review, we highlight current progress in understanding why and how the osteocyte removes and replaces bone tissue and the consequences of these activities to bone quality. We posit that answering these questions is essential for evaluating whether, how, when, and why LCS remodeling may be manipulated for therapeutic benefit in managing bone fragility.
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Affiliation(s)
- C M Heveran
- Department of Mechanical & Industrial Engineering, Montana State University, Bozeman, USA.
| | - J D Boerckel
- Department of Orthopaedic Surgery, Department of Bioengineering, University of Pennsylvania School of Medicine, Philadelphia, USA.
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20
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PINK1-mediated mitophagy contributes to glucocorticoid-induced cathepsin K production in osteocytes. J Orthop Translat 2023; 38:229-240. [DOI: 10.1016/j.jot.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 10/31/2022] [Accepted: 11/07/2022] [Indexed: 11/27/2022] Open
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21
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Wölfel EM, Lademann F, Hemmatian H, Blouin S, Messmer P, Hofbauer LC, Busse B, Rauner M, Jähn-Rickert K, Tsourdi E. Reduced Bone Mass and Increased Osteocyte Tartrate-Resistant Acid Phosphatase (TRAP) Activity, But Not Low Mineralized Matrix Around Osteocyte Lacunae, Are Restored After Recovery From Exogenous Hyperthyroidism in Male Mice. J Bone Miner Res 2023; 38:131-143. [PMID: 36331133 DOI: 10.1002/jbmr.4736] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 10/28/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022]
Abstract
Hyperthyroidism causes secondary osteoporosis through favoring bone resorption over bone formation, leading to bone loss with elevated bone fragility. Osteocytes that reside within lacunae inside the mineralized bone matrix orchestrate the process of bone remodeling and can themselves actively resorb bone upon certain stimuli. Nevertheless, the interaction between thyroid hormones and osteocytes and the impact of hyperthyroidism on osteocyte cell function are still unknown. In a preliminary study, we analyzed bones from male C57BL/6 mice with drug-induced hyperthyroidism, which led to mild osteocytic osteolysis with 1.14-fold larger osteocyte lacunae and by 108.33% higher tartrate-resistant acid phosphatase (TRAP) activity in osteocytes of hyperthyroid mice compared to euthyroid mice. To test whether hyperthyroidism-induced bone changes are reversible, we rendered male mice hyperthyroid by adding levothyroxine into their drinking water for 4 weeks, followed by a weaning period of 4 weeks with access to normal drinking water. Hyperthyroid mice displayed cortical and trabecular bone loss due to high bone turnover, which recovered with weaning. Although canalicular number and osteocyte lacunar area were similar in euthyroid, hyperthyroid and weaned mice, the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL)-positive osteocytes was 100% lower in the weaning group compared to euthyroid mice and the osteocytic TRAP activity was eightfold higher in hyperthyroid animals. The latter, along with a 3.75% lower average mineralization around the osteocyte lacunae in trabecular bone, suggests osteocytic osteolysis activity that, however, did not result in significantly enlarged osteocyte lacunae. In conclusion, we show a recovery of bone microarchitecture and turnover after reversal of hyperthyroidism to a euthyroid state. In contrast, osteocytic osteolysis was initiated in hyperthyroidism, but its effects were not reversed after 4 weeks of weaning. Due to the vast number of osteocytes in bone, we speculate that even minor individual cell functions might contribute to altered bone quality and mineral homeostasis in the setting of hyperthyroidism-induced bone disease. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Eva Maria Wölfel
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Franziska Lademann
- Department of Medicine III, Technische Universität Dresden Medical Center, Dresden, Germany.,Center for Healthy Aging, Technische Universität Dresden Medical Center, Dresden, Germany
| | - Haniyeh Hemmatian
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Stéphane Blouin
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
| | - Phaedra Messmer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
| | - Lorenz C Hofbauer
- Department of Medicine III, Technische Universität Dresden Medical Center, Dresden, Germany.,Center for Healthy Aging, Technische Universität Dresden Medical Center, Dresden, Germany
| | - Björn Busse
- Department of 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 Medical Center, Dresden, Germany
| | - Katharina Jähn-Rickert
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Mildred Scheel Cancer Career Center Hamburg, University Cancer Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Elena Tsourdi
- Department of Medicine III, Technische Universität Dresden Medical Center, Dresden, Germany.,Center for Healthy Aging, Technische Universität Dresden Medical Center, Dresden, Germany
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22
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You Q, Lu M, Li Z, Zhou Y, Tu C. Cell Sheet Technology as an Engineering-Based Approach to Bone Regeneration. Int J Nanomedicine 2022; 17:6491-6511. [PMID: 36573205 PMCID: PMC9789707 DOI: 10.2147/ijn.s382115] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 11/12/2022] [Indexed: 12/24/2022] Open
Abstract
Bone defects that are congenital or the result of infection, malignancy, or trauma represent a challenge to the global healthcare system. To address this issue, multiple research groups have been developing novel cell sheet technology (CST)-based approaches to promote bone regeneration. These methods hold promise for use in regenerative medicine because they preserve cell-cell contacts, cell-extracellular matrix interactions, and the protein makeup of cell membranes. This review introduces the concept and preparation system of the cell sheet (CS), explores the application of CST in bone regeneration, highlights the current states of the bone regeneration via CST, and offers perspectives on the challenges and future research direction of translating current knowledge from the lab to the clinic.
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Affiliation(s)
- Qi You
- Orthopedic Research Institute, Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, People’s Republic of China,Sichuan Model Worker and Craftsman Talent Innovation Research Studio, Chengdu, Sichuan Province, People’s Republic of China
| | - Minxun Lu
- Orthopedic Research Institute, Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, People’s Republic of China,Sichuan Model Worker and Craftsman Talent Innovation Research Studio, Chengdu, Sichuan Province, People’s Republic of China
| | - Zhuangzhuang Li
- Orthopedic Research Institute, Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, People’s Republic of China,Sichuan Model Worker and Craftsman Talent Innovation Research Studio, Chengdu, Sichuan Province, People’s Republic of China
| | - Yong Zhou
- Orthopedic Research Institute, Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, People’s Republic of China,Sichuan Model Worker and Craftsman Talent Innovation Research Studio, Chengdu, Sichuan Province, People’s Republic of China
| | - Chongqi Tu
- Orthopedic Research Institute, Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, People’s Republic of China,Sichuan Model Worker and Craftsman Talent Innovation Research Studio, Chengdu, Sichuan Province, People’s Republic of China,Correspondence: Chongqi Tu; Yong Zhou, Department of Orthopedics, West China Hospital, Sichuan University, No. 37, Guoxuexiang, Chengdu, 610041, Sichuan Province, People’s Republic of China, Email ;
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23
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Vadivalagan C, Krishnan A, Chen SJ, Hseu YC, Muthu S, Dhar R, Aljabali AAA, Tambuwala MM. The Warburg effect in osteoporosis: Cellular signaling and epigenetic regulation of energy metabolic events to targeting the osteocalcin for phenotypic alteration. Cell Signal 2022; 100:110488. [PMID: 36208706 DOI: 10.1016/j.cellsig.2022.110488] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 09/30/2022] [Accepted: 10/01/2022] [Indexed: 02/08/2023]
Abstract
Osteoporosis is a silent disease of skeletal morphology that induces fragility and fracture risk in aged persons irrespective of gender. Juvenile secondary osteoporosis is rare and is influenced by familial genetic abnormalities. Despite the currently available therapeutic options, more-acute treatments are in need. Women suffer from osteoporosis after menopause, which is characterized by a decline in the secretion of sex hormones in the later phase of life. Several studies in the past two decades emphasized hormone-related pathways to combat osteoporosis. Some studies partially examined energy-related pathways, but achieving a more vivid picture of metabolism and bone remodeling in terms of the Warburg phenomenon is still warranted. Each cell requires sufficient energy for cellular propagation and growth; in particular, osteoporosis is an energy-dependent mechanism affected by a decreased cellular mass of the bone morphology. Energy utilization is the actual propagation of such diseases, and narrowing down these criteria will hopefully provide clues to formulate better therapeutic strategies. Oxidative glycolysis is a particular type of energy metabolic pathway in cancer cells that influences cellular proliferation. Therefore, the prospect of utilizing collective glucose metabolism by inducing the Warburg effect may improve cell propagation. The benefits of utilizing the energy from the Warburg effect may be a difficult task. However, it seems to improve their effectiveness in the osteoblast phenotype by connecting the selected pathways such as WNT, Notch, AKT, and Insulin signaling by targeting osteocalcin resulting in phenotypic alteration. Osteocalcin directs ATP utilization through the sclerostin SOST gene in the bone microenvironment. Thus, selective activation of ATP production involved in osteoblast maturation remains a prime strategy to fight osteoporosis.
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Affiliation(s)
- Chithravel Vadivalagan
- Department of Cosmeceutics, College of Biopharmaceutical and Food Sciences, China Medical University, Taichung 40402, Taiwan.
| | - Anand Krishnan
- Department of Chemical Pathology, School of Pathology, Faculty of Health Sciences, University of the Free State, Bloemfontein 9300, South Africa.
| | - Siang-Jyun Chen
- Institute of Nutrition, College of Health Care, China Medical University, Taichung, 406040, Taiwan
| | - You-Cheng Hseu
- Department of Cosmeceutics, College of Biopharmaceutical and Food Sciences, China Medical University, Taichung 40402, Taiwan; Department of Health and Nutrition Biotechnology, Asia University, 41354, Taiwan; Chinese Medicine Research Center, China Medical University, Taichung 40402, Taiwan; Research Center of Chinese Herbal Medicine, China Medical University, Taichung 40402, Taiwan.
| | - Sathish Muthu
- Department of Orthopaedics, Government Medical College and Hospital, Dindigul-624003, Tamil Nadu, India
| | - Rajib Dhar
- Department of Genetic Engineering, SRM Institute of Science and Technology, Kattankulathur, -603203, Tamilnadu, India
| | - Alaa A A Aljabali
- Department of Pharmaceutics and Pharmaceutical Technology, Yarmouk University, Irbid, 21163, Jordan
| | - Murtaza M Tambuwala
- Lincoln Medical School, University of Lincoln, Brayford Pool Campus, Lincoln LN6 7TS, UK.
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Hongo H, Yokoyama A, Yamada-Sekiguchi T, Yamamoto T, Yoshino H, Abe M, Haraguchi-Kitakamae M, Luiz de Freitas PH, Hasegawa T, Li M. Histochemical assessment on osteocytic osteolysis in lactating mice fed with a calcium-insufficient diet. J Oral Biosci 2022; 64:422-430. [PMID: 36152933 DOI: 10.1016/j.job.2022.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 09/13/2022] [Accepted: 09/08/2022] [Indexed: 11/26/2022]
Abstract
OBJECTIVES This study aimed to examine if feeding lactating mice a calcium-insufficient diet while simultaneously administering alendronate (ALN) could potentially induce osteocytic osteolysis. METHODS Lactating mice were fed calcium (Ca)-insufficient diets with or without ALN administration, and then their femurs were examined for TRAP and ALP, and observed by Kossa staining and transmission electron microscopy (TEM). Mice that had been fed a Ca-insufficient diet were then fed a 44Ca-containinig diet, and their tibial sections were examined by isotope microscopy. RESULTS Mice fed a Ca-insufficient diet had a reduced number of TRAP-positive osteoclasts after ALN administration. ALN-treated, lactating mice fed a Ca-insufficient diet had enlarged lacunae in their cortical bones, and TEM imaging demonstrated expanded regions between osteocytes and lacunar walls. In ALN-treated lactating mice fed a Ca-insufficient diet, huge areas of demineralized bone matrix occurred, centered around blood vessels in the cortical bone. Isotope microscopy showed 44Ca in the vicinity of the osteocytic lacunae, and in the broad, previously demineralized region around the blood vessels in the cortical bone of lactating mice fed a 44Ca-sufficient diet. CONCLUSIONS Bone demineralization likely takes place in the periphery of the osteocytic lacunae and in the broad regions around the blood vessels of lactating mice when they are exposed to severely reduced serum Ca through a Ca-insufficient diet coupled with ALN administration.
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Affiliation(s)
- Hiromi Hongo
- Developmental Biology of Hard Tissue, Graduate School of Dental Medicine and Faculty of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Ayako Yokoyama
- Gerontology, Graduate School of Dental Medicine and Faculty of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Tamaki Yamada-Sekiguchi
- Oral and Maxillofacial Surgery, Graduate School of Dental Medicine and Faculty of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Tomomaya Yamamoto
- Developmental Biology of Hard Tissue, Graduate School of Dental Medicine and Faculty of Dental Medicine, Hokkaido University, Sapporo, Japan; Northern Army Medical Unit, Camp Makomanai, Japan Ground Self-Defense Forces, Sapporo, Japan
| | - Hirona Yoshino
- Developmental Biology of Hard Tissue, Graduate School of Dental Medicine and Faculty of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Miki Abe
- Developmental Biology of Hard Tissue, Graduate School of Dental Medicine and Faculty of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Mai Haraguchi-Kitakamae
- Developmental Biology of Hard Tissue, Graduate School of Dental Medicine and Faculty of Dental Medicine, Hokkaido University, Sapporo, Japan; Division of Craniofacial Development and Tissue Biology, Graduate School of Dentistry, Tohoku University, Sendai, Japan
| | | | - Tomoka Hasegawa
- Developmental Biology of Hard Tissue, Graduate School of Dental Medicine and Faculty of Dental Medicine, Hokkaido University, Sapporo, Japan.
| | - Minqi Li
- Shandong Provincial Key Laboratory of Oral Biomedicine, The School of Stomatology, Shandong University, Jinan, China
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25
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Damrath JG, Moe SM, Wallace JM. Calcimimetics Alter Periosteal and Perilacunar Bone Matrix Composition and Material Properties in Early Chronic Kidney Disease. J Bone Miner Res 2022; 37:1297-1306. [PMID: 35593150 PMCID: PMC9283238 DOI: 10.1002/jbmr.4574] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 04/19/2022] [Accepted: 05/18/2022] [Indexed: 11/15/2022]
Abstract
Chronic kidney disease (CKD) affects 15% of Americans and greatly increases fracture risk due to elevated parathyroid hormone, cortical porosity, and reduced bone material quality. Calcimimetic drugs are used to lower parathyroid hormone (PTH) in CKD patients, but their impact on bone matrix properties remains unknown. We hypothesized that tissue-level bone quality is altered in early CKD and that calcimimetic treatment will prevent these alterations. To test this hypothesis, we treated Cy/+ rats, a model of spontaneous and progressive CKD-mineral and bone disorder (CKD-MBD), with KP-2326, a preclinical analogue of etelcalcetide, early in the CKD disease course. To measure tissue-level bone matrix composition and material properties, we performed colocalized Raman spectroscopy and nanoindentation on new periosteal bone and perilacunar bone using hydrated femur sections. We found that CKD and KP treatment lowered mineral type B carbonate substitution whereas KP treatment increased mineral crystallinity in new periosteal bone. Reduced elastic modulus was lower in CKD but was not different in KP-treated rats versus CTRL. In perilacunar bone, KP treatment lowered type B carbonate substitution, increased crystallinity, and increased mineral-to-matrix ratio in a spatially dependent manner. KP treatment also increased reduced elastic modulus and hardness in a spatially dependent manner. Taken together, these data suggest that KP treatment improves material properties on the tissue level through a combination of lowering carbonate substitution, increasing mineral crystallinity, and increasing relative mineralization of the bone early in CKD. As a result, the mechanical properties were improved, and in some regions, were the same as control animals. Therefore, calcimimetics may help prevent CKD-induced bone deterioration by improving bone quality in new periosteal bone and in bone tissue near osteocyte lacunae. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- John G. Damrath
- Weldon School of Biomedical EngineeringPurdue UniversityWest LafayetteINUSA
| | - Sharon M. Moe
- Department of Medicine, Division of NephrologyIndiana University School of MedicineIndianapolisINUSA
| | - Joseph M. Wallace
- Department of Biomedical EngineeringIndiana University‐Purdue University at IndianapolisIndianapolisINUSA
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26
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Murshid SA. Bone permeability and mechanotransduction: Some current insights into the function of the lacunar-canalicular network. Tissue Cell 2022; 75:101730. [PMID: 35032785 DOI: 10.1016/j.tice.2022.101730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 10/19/2022]
Abstract
Lacunar-canalicular (LC) permeability involves the passage of fluids, nutrients, oxygen, ions, and signalling molecules through bone tissue, facilitating the maintenance of bone vitality and function and responses to various physiological conditions and diseases. LC permeability and fluid flow-shear stress/drag force play important roles in mechanotransduction in bone tissue by inducing mechanical stimuli in osteocytes, modulating cellular functions, and determining bone adaptation. Alterations in LC structure may therefore influence the fluid flow pattern through the LC network, thereby affecting the ability of osteocytes to sense and translate mechanical signals and possibly contributing to bone remodelling. Several bone-health conditions are associated with changes in LC structure and function and may affect mechanotransduction and responses, although the mechanisms underlying these associations are still not fully understood. In this review, recent studies of LC networks, their formation and transfer mechanical stimuli, and changes in structure, functional permeability, and mechanotransduction that result from age, pathology, and mechanical loading are discussed. Additionally, applications of vibration and low-intensity pulsed ultrasound in bone healthcare and regeneration fields are also presented.
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Affiliation(s)
- Sakhr Ahmed Murshid
- Institute for Globally Distributed Open Research and Education (IGDORE); Ilmajoki Health Public Dental Clinics, Social and Health Care Services in Jalasjärvi, Ilmajoki, Kurikka, Finland.
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27
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Choi JUA, Kijas AW, Lauko J, Rowan AE. The Mechanosensory Role of Osteocytes and Implications for Bone Health and Disease States. Front Cell Dev Biol 2022; 9:770143. [PMID: 35265628 PMCID: PMC8900535 DOI: 10.3389/fcell.2021.770143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 12/13/2021] [Indexed: 12/14/2022] Open
Abstract
Bone homeostasis is a dynamic equilibrium between bone-forming osteoblasts and bone-resorbing osteoclasts. This process is primarily controlled by the most abundant and mechanosensitive bone cells, osteocytes, that reside individually, within chambers of porous hydroxyapatite bone matrix. Recent studies have unveiled additional functional roles for osteocytes in directly contributing to local matrix regulation as well as systemic roles through endocrine functions by communicating with distant organs such as the kidney. Osteocyte function is governed largely by both biochemical signaling and the mechanical stimuli exerted on bone. Mechanical stimulation is required to maintain bone health whilst aging and reduced level of loading are known to result in bone loss. To date, both in vivo and in vitro approaches have been established to answer important questions such as the effect of mechanical stimuli, the mechanosensors involved, and the mechanosensitive signaling pathways in osteocytes. However, our understanding of osteocyte mechanotransduction has been limited due to the technical challenges of working with these cells since they are individually embedded within the hard hydroxyapatite bone matrix. This review highlights the current knowledge of the osteocyte functional role in maintaining bone health and the key regulatory pathways of these mechanosensitive cells. Finally, we elaborate on the current therapeutic opportunities offered by existing treatments and the potential for targeting osteocyte-directed signaling.
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Affiliation(s)
- Jung Un Ally Choi
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Amanda W Kijas
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Jan Lauko
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Alan E Rowan
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
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28
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Moharrer Y, Boerckel JD. Tunnels in the rock: Dynamics of osteocyte morphogenesis. Bone 2021; 153:116104. [PMID: 34245936 PMCID: PMC8478866 DOI: 10.1016/j.bone.2021.116104] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 06/11/2021] [Accepted: 06/28/2021] [Indexed: 11/27/2022]
Abstract
Osteocytes are dynamic, bone matrix-remodeling cells that form an intricate network of interconnected projections through the bone matrix, called the lacunar-canalicular system. Osteocytes are the dominant mechanosensory cells in bone and their mechanosensory and mechanotransductive functions follow their morphological form. During osteocytogenesis and development of the osteocyte lacunar-canalicular network, osteocytes must dramatically remodel both their cytoskeleton and their extracellular matrix. In this review, we summarize our current understanding of the mechanisms that govern osteocyte differentiation, cytoskeletal morphogenesis, mechanotransduction, and matrix remodeling. We postulate that the physiologic activation of matrix remodeling in adult osteocytes, known as perilacunar/canalicular remodeling (PLR) represents a re-activation of the developmental program by which the osteocyte network is first established. While much of osteocyte biology remains unclear, new tools and approaches make the present moment a particularly fruitful and exciting time to study the development of these remarkable cells.
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Affiliation(s)
- Yasaman Moharrer
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States of America; Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Joel D Boerckel
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States of America; Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, United States of America; Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States of America.
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29
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Jiang M, Ding Y, Xu S, Hao X, Yang Y, Luo E, Jing D, Yan Z, Cai J. Radiotherapy-induced bone deterioration is exacerbated in diabetic rats treated with streptozotocin. Braz J Med Biol Res 2021; 54:e11550. [PMID: 34730682 PMCID: PMC8555449 DOI: 10.1590/1414-431x2021e11550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 09/06/2021] [Indexed: 11/30/2022] Open
Abstract
Following radiotherapy, patients have decreased bone mass and increased risk of fragility fractures. Diabetes mellitus (DM) is also reported to have detrimental effects on bone architecture and quality. However, no clinical or experimental study has systematically characterized the bone phenotype of the diabetic patients following radiotherapy. After one month of streptozotocin injection, three-month-old male rats were subjected to focal radiotherapy (8 Gy, twice, at days 1 and 3), and then bone mass, microarchitecture, and turnover as well as bone cell activities were evaluated at 2 months post-irradiation. Micro-computed tomography results demonstrated that DM rats exhibited greater deterioration in trabecular bone mass and microarchitecture following irradiation compared with the damage to bone structure induced by DM or radiotherapy. The serum biochemical, bone histomorphometric, and gene expression assays revealed that DM combined with radiotherapy showed lower bone formation rate, osteoblast number on bone surface, and expression of osteoblast-related markers (ALP, Runx2, Osx, and Col-1) compared with DM or irradiation alone. DM plus irradiation also caused higher bone resorption rate, osteoclast number on bone surface, and expression of osteoclast-specific markers (TRAP, cathepsin K, and calcitonin receptor) than DM or irradiation treatment alone. Moreover, lower osteocyte survival and higher expression of Sost and DKK1 genes (two negative modulators of Wnt signaling) were observed in rats with combined DM and radiotherapy. Together, these findings revealed a higher deterioration of the diabetic skeleton following radiotherapy, and emphasized the clinical importance of health maintenance.
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Affiliation(s)
- Maogang Jiang
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Yuanjun Ding
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Shiwei Xu
- Department of Medical Technical Support, NCO School of Army Medical University, Shijiazhuang, China
| | - Xiaoxia Hao
- Laboratory of Tissue Engineering, Faculty of Life Sciences, Northwest University, Xi'an, China
| | - Yongqing Yang
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Erping Luo
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Da Jing
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.,State Key Laboratory of Military Stomatology, Fourth Military Medical University, Xi'an, China
| | - Zedong Yan
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Jing Cai
- College of Basic Medicine, Shaanxi University of Chinese Medicine, Xianyang, China
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30
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Hemmatian H, Conrad S, Furesi G, Mletzko K, Krug J, Faila AV, Kuhlmann JD, Rauner M, Busse B, Jähn-Rickert K. Reorganization of the osteocyte lacuno-canalicular network characteristics in tumor sites of an immunocompetent murine model of osteotropic cancers. Bone 2021; 152:116074. [PMID: 34174502 DOI: 10.1016/j.bone.2021.116074] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/04/2021] [Accepted: 06/18/2021] [Indexed: 11/16/2022]
Abstract
Mechanosensitive osteocytes are central regulators of bone resorption and formation. However, during the formation of bone metastases, which arise as consequences of breast and prostate cancer and skew homeostatic bone remodeling to favor osteolytic, osteosclerotic or mixed lesions, only a paucity of data exists on tumor-associated osteocyte interaction. Herein, we used a suite of high-resolution imaging and histological techniques to evaluate the effect of osteotropic cancer on cortical bone microarchitecture. Confocal imaging highlighted a direct contact between tumor cells residing in the bone marrow and osteocytes. High-resolution microcomputed tomography revealed a 10-12% larger osteocyte lacuna volume in the presence of tumor cells at day 21 after intratibial injection of EO771-Luc breast and RM1-Luc prostate cancer cells. The 3D representative of the spatial distribution of cortical bone microporosity showed i) a regional accumulation of vascular canals and large lacunae with low connectivity in osteosclerotic regions of interest and ii) an absence of vascular canals and large lacunae in osteolytic regions. These findings pinpoint the relationship between the presence of tumor cells in the bone marrow microenvironment and osteocyte lacunar characteristics and cortical bone blood vessel structure.
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Affiliation(s)
- Haniyeh Hemmatian
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 55a, 22529 Hamburg, Germany
| | - Stefanie Conrad
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Giulia Furesi
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Kathrin Mletzko
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 55a, 22529 Hamburg, Germany
| | - Johannes Krug
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 55a, 22529 Hamburg, Germany
| | - Antonio Virgilio Faila
- Microscopy Imaging Facility, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jan Dominik Kuhlmann
- Department of Gynecology and Obstetrics, Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Martina Rauner
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany.
| | - Björn Busse
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 55a, 22529 Hamburg, Germany; Interdisciplinary Competence Center for Interface Research (ICCIR), Hamburg, Germany; Forum Medical Technology Health Hamburg (FMTHH), Hamburg, Germany.
| | - Katharina Jähn-Rickert
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 55a, 22529 Hamburg, Germany; Mildred Scheel Cancer Career Center Hamburg, University Cancer Center Hamburg, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg.
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31
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Lai X, Chung R, Li Y, Liu XS, Wang L. Lactation alters fluid flow and solute transport in maternal skeleton: A multiscale modeling study on the effects of microstructural changes and loading frequency. Bone 2021; 151:116033. [PMID: 34102350 PMCID: PMC8276854 DOI: 10.1016/j.bone.2021.116033] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 04/23/2021] [Accepted: 06/01/2021] [Indexed: 01/02/2023]
Abstract
The female skeleton undergoes significant material and ultrastructural changes to meet high calcium demands during reproduction and lactation. Through the peri-lacunar/canalicular remodeling (PLR), osteocytes actively resorb surrounding matrix and enlarge their lacunae and canaliculi during lactation, which are quickly reversed after weaning. How these changes alter the physicochemical environment of osteocytes, the most abundant and primary mechanosensing cells in bone, are not well understood. In this study, we developed a multiscale poroelastic modeling technique to investigate lactation-induced changes in stress, fluid pressurization, fluid flow, and solute transport across multiple length scales (whole bone, porous midshaft cortex, lacunar-canalicular pore system (LCS), and pericellular matrix (PCM) around osteocytes) in murine tibiae subjected to axial compression at 3 N peak load (~320 με) at 0.5, 2, or 4 Hz. Based on previously reported skeletal anatomical measurements from lactating and nulliparous mice, our models demonstrated that loading frequency, LCS porosity, and PCM density were major determinants of fluid and solute flows responsible for osteocyte mechanosensing, cell-cell signaling, and metabolism. When loaded at 0.5 Hz, lactation-induced LCS expansion and potential PCM reduction promoted solute transport and osteocyte mechanosensing via primary cilia, but suppressed mechanosensing via fluid shear and/or drag force on the cell membrane. Interestingly, loading at 2 or 4 Hz was found to overcome the mechanosensing deficits observed at 0.5 Hz and these counter effects became more pronounced at 4 Hz and with sparser PCM in the lactating bone. Synergistically, higher loading frequency (2, 4 Hz) and sparser PCM enhanced flow-mediated mechanosensing and diffusion/convection of nutrients and signaling molecules for osteocytes. In summary, lactation-induced structural changes alter the local environment of osteocytes in ways that favor metabolism, mechanosensing, and post-weaning recovery of maternal bone. Thus, osteocytes play a role in balancing the metabolic and mechanical functions of female skeleton during reproduction and lactation.
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Affiliation(s)
- Xiaohan Lai
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China.
| | - Rebecca Chung
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Yihan Li
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Xiaowei Sherry Liu
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Liyun Wang
- Department of Mechanical Engineering, University of Delaware, United States.
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32
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Li Y, de Bakker CMJ, Lai X, Zhao H, Parajuli A, Tseng WJ, Pei S, Meng T, Chung R, Wang L, Liu XS. Maternal bone adaptation to mechanical loading during pregnancy, lactation, and post-weaning recovery. Bone 2021; 151:116031. [PMID: 34098162 PMCID: PMC8504362 DOI: 10.1016/j.bone.2021.116031] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 04/25/2021] [Accepted: 06/01/2021] [Indexed: 12/16/2022]
Abstract
The maternal skeleton undergoes dramatic bone loss during pregnancy and lactation, and substantial bone recovery post-weaning. The structural adaptations of maternal bone during reproduction and lactation exert a better protection of the mechanical integrity at the critical load-bearing sites, suggesting the importance of physiological load-bearing in regulating reproduction-induced skeletal alterations. Although it is suggested that physical exercise during pregnancy and breastfeeding improves women's physical and psychological well-being, its effects on maternal bone health remain unclear. Therefore, the objective of this study was to investigate the maternal bone adaptations to external mechanical loading during pregnancy, lactation, and post-weaning recovery. By utilizing an in vivo dynamic tibial loading protocol in a rat model, we demonstrated improved maternal cortical bone structure in response to dynamic loading at tibial midshaft, regardless of reproductive status. Notably, despite the minimal loading responses detected in the trabecular bone in virgins, rat bone during lactation experienced enhanced mechano-responsiveness in both trabecular and cortical bone compartments when compared to rats at other reproductive stages or age-matched virgins. Furthermore, our study showed that the lactation-induced elevation in osteocyte peri-lacunar/canalicular remodeling (PLR) activities led to enlarged osteocyte lacunae. This may result in alterations in interstitial fluid flow-mediated mechanical stimulation on osteocytes and an elevation in solute transport through the lacunar-canalicular system (LCS) during high-frequency dynamic loading, thus enhancing mechano-responsiveness of maternal bone during lactation. Taken together, findings from this study provide important insights into the relationship between reproduction- and lactation-induced skeletal changes and external mechanical loading, emphasizing the importance of weight-bearing exercise on maternal bone health during reproduction and postpartum.
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Affiliation(s)
- Yihan Li
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Chantal M J de Bakker
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Department of Radiology, Cumming School of Medicine, McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Canada
| | - Xiaohan Lai
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Hongbo Zhao
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Ashutosh Parajuli
- Center for Biomechanical Research, Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - Wei-Ju Tseng
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Shaopeng Pei
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Center for Biomechanical Research, Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - Tan Meng
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Rebecca Chung
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Liyun Wang
- Center for Biomechanical Research, Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - X Sherry Liu
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
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Cooper ID, Brookler KH, Crofts CAP. Rethinking Fragility Fractures in Type 2 Diabetes: The Link between Hyperinsulinaemia and Osteofragilitas. Biomedicines 2021; 9:1165. [PMID: 34572351 PMCID: PMC8472634 DOI: 10.3390/biomedicines9091165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/27/2021] [Accepted: 09/02/2021] [Indexed: 02/06/2023] Open
Abstract
Patients with type 2 diabetes mellitus (T2DM) and/or cardiovascular disease (CVD), conditions of hyperinsulinaemia, have lower levels of osteocalcin and bone remodelling, and increased rates of fragility fractures. Unlike osteoporosis with lower bone mineral density (BMD), T2DM bone fragility "hyperinsulinaemia-osteofragilitas" phenotype presents with normal to increased BMD. Hyperinsulinaemia and insulin resistance positively associate with increased BMD and fragility fractures. Hyperinsulinaemia enforces glucose fuelling, which decreases NAD+-dependent antioxidant activity. This increases reactive oxygen species and mitochondrial fission, and decreases oxidative phosphorylation high-energy production capacity, required for osteoblasto/cytogenesis. Osteocytes directly mineralise and resorb bone, and inhibit mineralisation of their lacunocanalicular space via pyrophosphate. Hyperinsulinaemia decreases vitamin D availability via adipocyte sequestration, reducing dendrite connectivity, and compromising osteocyte viability. Decreased bone remodelling and micropetrosis ensues. Trapped/entombed magnesium within micropetrosis fossilisation spaces propagates magnesium deficiency (MgD), potentiating hyperinsulinaemia and decreases vitamin D transport. Vitamin D deficiency reduces osteocalcin synthesis and favours osteocyte apoptosis. Carbohydrate restriction/fasting/ketosis increases beta-oxidation, ketolysis, NAD+-dependent antioxidant activity, osteocyte viability and osteocalcin, and decreases excess insulin exposure. Osteocalcin is required for hydroxyapatite alignment, conferring bone structural integrity, decreasing fracture risk and improving metabolic/endocrine homeodynamics. Patients presenting with fracture and normal BMD should be investigated for T2DM and hyperinsulinaemia.
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Affiliation(s)
- Isabella D. Cooper
- Translational Physiology Research Group, School of Life Sciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK
| | - Kenneth H. Brookler
- Research Collaborator, Aerospace Medicine and Vestibular Research Laboratory, Mayo Clinic, Scottsdale, AZ 85259, USA;
| | - Catherine A. P. Crofts
- School of Public Health and Interdisciplinary Studies, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland 0627, New Zealand;
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Jähn-Rickert K, Zimmermann EA. Potential Role of Perilacunar Remodeling in the Progression of Osteoporosis and Implications on Age-Related Decline in Fracture Resistance of Bone. Curr Osteoporos Rep 2021; 19:391-402. [PMID: 34117624 DOI: 10.1007/s11914-021-00686-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/22/2021] [Indexed: 12/21/2022]
Abstract
PURPOSE OF REVIEW We took an interdisciplinary view to examine the potential contribution of perilacunar/canalicular remodeling to declines in bone fracture resistance related to age or progression of osteoporosis. RECENT FINDINGS Perilacunar remodeling is most prominent as a result of lactation; recent advances further elucidate the molecular players involved and their effect on bone material properties. Of these, vitamin D and calcitonin could be active during aging or osteoporosis. Menopause-related hormonal changes or osteoporosis therapies affect bone material properties and mechanical behavior. However, investigations of lacunar size or osteocyte TRAP activity with age or osteoporosis do not provide clear evidence for or against perilacunar remodeling. While the occurrence and potential role of perilacunar remodeling in aging and osteoporosis progression are largely under-investigated, widespread changes in bone matrix composition in OVX models and following osteoporosis therapies imply osteocytic maintenance of bone matrix. Perilacunar remodeling-induced changes in bone porosity, bone matrix composition, and bone adaptation could have significant implications for bone fracture resistance.
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Affiliation(s)
- Katharina Jähn-Rickert
- Heisenberg Research Group, Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 55a, 22529, Hamburg, Germany.
- Mildred Scheel Cancer Career Center Hamburg, University Cancer Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Elizabeth A Zimmermann
- Faculty of Dentistry, McGill University, Strathcona Anatomy and Dentistry Building, 3640 Rue University, Montreal, Canada.
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Abstract
PURPOSE OF REVIEW In this review, we provide a recent update on bioenergetic pathways in osteocytes and identify potential future areas of research interest. Studies have identified a role for regulation of bone formation and bone resorption through osteocyte mechanosensing and osteocyte secreted factors. Nevertheless, there is a paucity of studies on the bioenergetics and energy metabolism of osteocytes, which are required for the regulation of bone remodeling. RECENT FINDINGS Osteocytes are cells of the osteoblast lineage embedded in bone. The osteocyte lacunocanalicular network within the skeletal matrix is exposed to a unique hypoxic environment. Therefore, the bioenergetic requirements of these cells could differ from other bone cells due to its location in the ossified matrix and its role in bone regulation transduced by mechanical signals. Recent findings highlighted in this review provide some evidence that metabolism of these cells is dependent on their location due to the substrates present in the microenvironment and metabolic cues from stress pathways. Both glycolysis (glucose metabolism) and oxidative phosphorylation (mitochondrial dynamics, ROS generation) affect osteocyte function and viability. In this review, we provide evidence that is currently available about information regarding bioenergetics pathways in osteocytes. We discuss published studies showing a role for hypoxia-driven glucose metabolism in regulating osteocyte bioenergetics. We also provide information on various substrates that osteocytes could utilize to fuel energetic needs, namely pyruvate, amino acids, and fatty acids. This is based on some preliminary experimental evidence that is available in literature. The role of parathyroid hormone PTH and parathryoid hormone-related peptide PTHrP in bone anabolism and resorption, along with regulation of metabolic pathways in the cells of the skeletal niche, needs to be explored further. Mitochondrial metabolism has a role in osteocyte bioenergetics through substrate utilization, location of the osteocyte in the bone cortex, and mitochondrial biogenesis. While there are limitations in studying metabolic flux in traditional cell lines, there are now novel cell lines and sophisticated tools available to study osteocyte bioenergetics to help harness its potential in vivo in the future.
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Affiliation(s)
- Vivin Karthik
- Center for Molecular Medicine, Maine Medical Center Research Institute, 81 Research Drive, Scarborough, ME, 04074, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
| | - Anyonya R Guntur
- Center for Molecular Medicine, Maine Medical Center Research Institute, 81 Research Drive, Scarborough, ME, 04074, USA.
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA.
- Tufts University School of Medicine, Tufts University, Boston, MA, USA.
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Di Pompo G, Cortini M, Baldini N, Avnet S. Acid Microenvironment in Bone Sarcomas. Cancers (Basel) 2021; 13:cancers13153848. [PMID: 34359749 PMCID: PMC8345667 DOI: 10.3390/cancers13153848] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/24/2021] [Accepted: 07/28/2021] [Indexed: 12/15/2022] Open
Abstract
Simple Summary Although rare, malignant bone sarcomas have devastating clinical implications for the health and survival of young adults and children. To date, efforts to identify the molecular drivers and targets have focused on cancer cells or on the interplay between cancer cells and stromal cells in the tumour microenvironment. On the contrary, in the current literature, the role of the chemical-physical conditions of the tumour microenvironment that may be implicated in sarcoma aggressiveness and progression are poorly reported and discussed. Among these, extracellular acidosis is a well-recognized hallmark of bone sarcomas and promotes cancer growth and dissemination but data presented on this topic are fragmented. Hence, we intended to provide a general and comprehensive overview of the causes and implications of acidosis in bone sarcoma. Abstract In bone sarcomas, extracellular proton accumulation is an intrinsic driver of malignancy. Extracellular acidosis increases stemness, invasion, angiogenesis, metastasis, and resistance to therapy of cancer cells. It reprograms tumour-associated stroma into a protumour phenotype through the release of inflammatory cytokines. It affects bone homeostasis, as extracellular proton accumulation is perceived by acid-sensing ion channels located at the cell membrane of normal bone cells. In bone, acidosis results from the altered glycolytic metabolism of bone cancer cells and the resorption activity of tumour-induced osteoclasts that share the same ecosystem. Proton extrusion activity is mediated by extruders and transporters located at the cell membrane of normal and transformed cells, including vacuolar ATPase and carbonic anhydrase IX, or by the release of highly acidic lysosomes by exocytosis. To date, a number of investigations have focused on the effects of acidosis and its inhibition in bone sarcomas, including studies evaluating the use of photodynamic therapy. In this review, we will discuss the current status of all findings on extracellular acidosis in bone sarcomas, with a specific focus on the characteristics of the bone microenvironment and the acid-targeting therapeutic approaches that are currently being evaluated.
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Affiliation(s)
- Gemma Di Pompo
- Biomedical Science and Technologies Lab, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (G.D.P.); (M.C.); (N.B.)
| | - Margherita Cortini
- Biomedical Science and Technologies Lab, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (G.D.P.); (M.C.); (N.B.)
| | - Nicola Baldini
- Biomedical Science and Technologies Lab, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (G.D.P.); (M.C.); (N.B.)
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126 Bologna, Italy
| | - Sofia Avnet
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126 Bologna, Italy
- Correspondence:
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Non-bone metastatic cancers promote osteocyte-induced bone destruction. Cancer Lett 2021; 520:80-90. [PMID: 34233150 DOI: 10.1016/j.canlet.2021.06.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 06/24/2021] [Accepted: 06/29/2021] [Indexed: 02/07/2023]
Abstract
The effects of bone metastatic cancer on the skeleton are well described, whereas less is known regarding the effects of non-metastatic bone cancer on bone. Here we investigated the effects of three non-bone metastatic cancer cachexia models, namely Colon-26 adenocarcinoma (C26), ES-2 ovarian cancer (ES-2), and Lewis lung carcinoma (LLC). Even though C26, ES-2 and LLC tumor growth resulted in comparable weight and muscle loss, the ES-2 and LLC hosts exhibited severe bone loss, whereas only modest bone loss was observed in the C26 bearers, correlating with increased TRAP+ osteoclasts in the femurs of ES-2 and LLC but not C26 hosts. Surprisingly, all three showed increased osteocyte lacunar area indicating osteocytic osteolysis and displayed dramatically increased osteocyte death, as well as empty lacunae. To test whether tumor-secreted factors were responsible for the observed effect, IDG-SW3 osteocyte cells were co-cultured with cancer cells in permeable trans-wells. Apoptosis was observed in the osteocyte cells exposed to all three cancer cell lines suggesting that all tumors were cytotoxic for osteocytes. In addition, the expression of the osteoclastic markers, Acp5, CtsK, Atp6v0d2 and Mmp13, was elevated in IDG-SW3 osteocytes exposed to tumor factors, supporting the in vivo observations of increased lacunar size due to osteocytic osteolysis. For the first time, we describe osteocytic bone destruction and extensive osteocyte cell death in non-bone metastatic cancer. These bone alterations, in conjunction with muscle wasting, may create a musculoskeletal system that is incapable of full recovery upon eradication of tumor. Co-treatment with bone preserving therapies should be considered.
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Kovacs CS, Chaussain C, Osdoby P, Brandi ML, Clarke B, Thakker RV. The role of biomineralization in disorders of skeletal development and tooth formation. Nat Rev Endocrinol 2021; 17:336-349. [PMID: 33948016 DOI: 10.1038/s41574-021-00488-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/19/2021] [Indexed: 02/03/2023]
Abstract
The major mineralized tissues are bone and teeth, which share several mechanisms governing their development and mineralization. This crossover includes the hormones that regulate circulating calcium and phosphate concentrations, and the genes that regulate the differentiation and transdifferentiation of cells. In developing endochondral bone and in developing teeth, parathyroid hormone-related protein (PTHrP) acts in chondrocytes to delay terminal differentiation, thereby increasing the pool of precursor cells. Chondrocytes and (in specific circumstances) pre-odontoblasts can also transdifferentiate into osteoblasts. Moreover, bone and teeth share outcomes when affected by systemic disorders of mineral homeostasis or of the extracellular matrix, and by adverse effects of treatments such as bisphosphonates and fluoride. Unlike bone, teeth have more permanent effects from systemic disorders because they are not remodelled after they are formed. This Review discusses the normal processes of bone and tooth development, followed by disorders that have effects on both bone and teeth, versus disorders that have effects in one without affecting the other. The takeaway message is that bone specialists should know when to screen for dental disorders, just as dental specialists should recognize when a tooth disorder should raise suspicions about a possible underlying bone disorder.
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Affiliation(s)
- Christopher S Kovacs
- Faculty of Medicine - Endocrinology, Memorial University of Newfoundland, St. John's, NL, Canada.
| | | | - Philip Osdoby
- Department of Biology, Washington University, St. Louis, MO, USA
| | - Maria Luisa Brandi
- Department of Biochemical, Experimental and Clinical Sciences, University of Florence, Florence, Italy
| | - Bart Clarke
- Mayo Clinic Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Rochester, MN, USA
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
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Youlten SE, Kemp JP, Logan JG, Ghirardello EJ, Sergio CM, Dack MRG, Guilfoyle SE, Leitch VD, Butterfield NC, Komla-Ebri D, Chai RC, Corr AP, Smith JT, Mohanty ST, Morris JA, McDonald MM, Quinn JMW, McGlade AR, Bartonicek N, Jansson M, Hatzikotoulas K, Irving MD, Beleza-Meireles A, Rivadeneira F, Duncan E, Richards JB, Adams DJ, Lelliott CJ, Brink R, Phan TG, Eisman JA, Evans DM, Zeggini E, Baldock PA, Bassett JHD, Williams GR, Croucher PI. Osteocyte transcriptome mapping identifies a molecular landscape controlling skeletal homeostasis and susceptibility to skeletal disease. Nat Commun 2021; 12:2444. [PMID: 33953184 PMCID: PMC8100170 DOI: 10.1038/s41467-021-22517-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 03/11/2021] [Indexed: 12/17/2022] Open
Abstract
Osteocytes are master regulators of the skeleton. We mapped the transcriptome of osteocytes from different skeletal sites, across age and sexes in mice to reveal genes and molecular programs that control this complex cellular-network. We define an osteocyte transcriptome signature of 1239 genes that distinguishes osteocytes from other cells. 77% have no previously known role in the skeleton and are enriched for genes regulating neuronal network formation, suggesting this programme is important in osteocyte communication. We evaluated 19 skeletal parameters in 733 knockout mouse lines and reveal 26 osteocyte transcriptome signature genes that control bone structure and function. We showed osteocyte transcriptome signature genes are enriched for human orthologs that cause monogenic skeletal disorders (P = 2.4 × 10-22) and are associated with the polygenic diseases osteoporosis (P = 1.8 × 10-13) and osteoarthritis (P = 1.6 × 10-7). Thus, we reveal the molecular landscape that regulates osteocyte network formation and function and establish the importance of osteocytes in human skeletal disease.
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Affiliation(s)
- Scott E Youlten
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
| | - John P Kemp
- University of Queensland Diamantina Institute, UQ, Brisbane, QLD, Australia
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
| | - John G Logan
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Elena J Ghirardello
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Claudio M Sergio
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Michael R G Dack
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Siobhan E Guilfoyle
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Victoria D Leitch
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
- RMIT Centre for Additive Manufacturing, School of Engineering, RMIT University, Melbourne, VIC, UK
| | - Natalie C Butterfield
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Davide Komla-Ebri
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Ryan C Chai
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Alexander P Corr
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
- Faculty of Science, University of Bath, Bath, UK
| | - James T Smith
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
- Faculty of Science, University of Bath, Bath, UK
| | - Sindhu T Mohanty
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - John A Morris
- New York Genome Center, New York, NY, USA
- Faculty of Arts and Science, Department of Biology, New York University, New York, NY, USA
| | - Michelle M McDonald
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
| | - Julian M W Quinn
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Amelia R McGlade
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Nenad Bartonicek
- Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Darlinghurst, Sydney, NSW, Australia
| | - Matt Jansson
- Viapath Genetics Laboratory, Viapath Analytics LLP, Guy's Hospital, London, UK
- Department of Clinical Genetics, Guy's Hospital, London, UK
| | - Konstantinos Hatzikotoulas
- Institute of Translational Genomics, Helmholtz Zentrum München - German Research Center for Environmental Health, Phoenix, AZ, USA
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Melita D Irving
- Department of Clinical Genetics, Guy's and St Thomas' NHS Trust, London, UK
| | | | | | - Emma Duncan
- Faculty of Life Sciences and Medicine, Department of Twin Research & Genetic Epidemiology, School of Life Course Sciences, King's College London, London, UK
- Australian Translational Genomics Centre, Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology, Brisbane, QLD, Australia
- Faculty of Medicine, University of Queensland, St Lucia, QLD, Australia
| | - J Brent Richards
- Faculty of Life Sciences and Medicine, Department of Twin Research & Genetic Epidemiology, School of Life Course Sciences, King's College London, London, UK
- Faculty of Medicine, McGill University, Quebec, Canada
| | | | | | - Robert Brink
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
- Division of Immunology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Tri Giang Phan
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
- Division of Immunology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - John A Eisman
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
- School of Medicine Sydney, University of Notre Dame Australia, Fremantle, Australia
| | - David M Evans
- University of Queensland Diamantina Institute, UQ, Brisbane, QLD, Australia
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
| | - Eleftheria Zeggini
- Institute of Translational Genomics, Helmholtz Zentrum München - German Research Center for Environmental Health, Phoenix, AZ, USA
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Paul A Baldock
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - J H Duncan Bassett
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.
| | - Graham R Williams
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.
| | - Peter I Croucher
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia.
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia.
- School of Biotechnology and Biomolecular Sciences, UNSW Australia, Sydney, Australia.
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Haridy Y, Osenberg M, Hilger A, Manke I, Davesne D, Witzmann F. Bone metabolism and evolutionary origin of osteocytes: Novel application of FIB-SEM tomography. SCIENCE ADVANCES 2021; 7:eabb9113. [PMID: 33789889 PMCID: PMC8011976 DOI: 10.1126/sciadv.abb9113] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 02/11/2021] [Indexed: 06/10/2023]
Abstract
Lacunae and canaliculi spaces of osteocytes are remarkably well preserved in fossilized bone and serve as an established proxy for bone cells. The earliest bone in the fossil record is acellular (anosteocytic), followed by cellular (osteocytic) bone in the jawless relatives of jawed vertebrates, the osteostracans, about 400 million years ago. Virtually nothing is known about the physiological pressures that would have initially favored osteocytic over anosteocytic bone. We apply focused ion beam-scanning electron microscopy tomography combined with machine learning for cell detection and segmentation to image fossil cell spaces. Novel three-dimensional high-resolution images reveal areas of low density around osteocyte lacunae and their canaliculi in osteostracan bone. This provides evidence for demineralization that would have occurred in vivo as part of osteocytic osteolysis, a mechanism of mineral homeostasis, supporting the hypothesis that a physiological demand for phosphorus was the principal driver in the initial evolution of osteocytic bone.
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Affiliation(s)
- Yara Haridy
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany.
| | - Markus Osenberg
- Helmholtz Centre for Materials and Energy (HZB), Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - André Hilger
- Helmholtz Centre for Materials and Energy (HZB), Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Ingo Manke
- Helmholtz Centre for Materials and Energy (HZB), Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Donald Davesne
- Department of Earth Sciences, University of Oxford, OX1 3AN Oxford, UK
- Institut de Systématique, Évolution, Biodiversité (UMR 7205), Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE, 75005 Paris, France
| | - Florian Witzmann
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
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Vahidi G, Rux C, Sherk VD, Heveran CM. Lacunar-canalicular bone remodeling: Impacts on bone quality and tools for assessment. Bone 2021; 143:115663. [PMID: 32987198 PMCID: PMC7769905 DOI: 10.1016/j.bone.2020.115663] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/23/2020] [Accepted: 09/23/2020] [Indexed: 01/06/2023]
Abstract
Osteocytes can resorb as well as replace bone adjacent to the expansive lacunar-canalicular system (LCS). Suppressed LCS remodeling decreases bone fracture toughness, but it is unclear how altered LCS remodeling impacts bone quality. The first goal of this review is to assess how LCS remodeling impacts LCS morphology as well as the composition and mechanical properties of surrounding bone tissue. The second goal is to compare tools available for the assessment of bone quality at length-scales that are physiologically-relevant to LCS remodeling. We find that changes to LCS morphology occur in response to a variety of physiological conditions and diseases and can be classified in two general phenotypes. In the 'aging phenotype', seen in aging and in some disuse models, the LCS is truncated and osteocytes apoptosis is increased. In the 'osteocytic osteolysis' phenotype, which is adaptive in some physiological settings and possibly maladaptive in others, the LCS enlarges and osteocytes generally maintain viability. Bone composition and mechanical properties vary near the osteocyte and change with at least some conditions that alter LCS morphology. However, few studies have evaluated bone composition and mechanical properties close to the LCS and so the impacts of LCS remodeling phenotypes on bone tissue quality are still undetermined. We summarize the current understanding of how LCS remodeling impacts LCS morphology, tissue-scale bone composition and mechanical properties, and whole-bone material properties. Tools are compared for assessing tissue-scale bone properties, as well as the resolution, advantages, and limitations of these techniques.
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Affiliation(s)
- G Vahidi
- Department of Mechanical & Industrial Engineering, Montana State University, United States of America
| | - C Rux
- Department of Mechanical & Industrial Engineering, Montana State University, United States of America
| | - V D Sherk
- Department of Orthopedics, University of Colorado Anschutz School of Medicine, United States of America
| | - C M Heveran
- Department of Mechanical & Industrial Engineering, Montana State University, United States of America.
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Bailey KN, Nguyen J, Yee CS, Dole NS, Dang A, Alliston T. Mechanosensitive Control of Articular Cartilage and Subchondral Bone Homeostasis in Mice Requires Osteocytic Transforming Growth Factor β Signaling. Arthritis Rheumatol 2021; 73:414-425. [PMID: 33022131 DOI: 10.1002/art.41548] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 09/23/2020] [Indexed: 12/25/2022]
Abstract
OBJECTIVE Transforming growth factor β (TGFβ) signaling plays a complex tissue-specific and nonlinear role in osteoarthritis (OA). This study was conducted to determine the osteocytic contributions of TGFβ signaling to OA. METHODS To identify the role of osteocytic TGFβ signaling in joint homeostasis, we used 16-week-old male mice (n = 9-11 per group) and female mice (n = 7-11 per group) with an osteocyte-intrinsic ablation of TGFβ receptor type II (TβRIIocy-/- mice) and assessed defects in cartilage degeneration, subchondral bone plate (SBP) thickness, and SBP sclerostin expression. To further investigate these mechanisms in 16-week-old male mice, we perturbed joint homeostasis by subjecting 8-week-old mice to medial meniscal/ligamentous injury (MLI), which preferentially disrupts the mechanical environment of the medial joint to induce OA. RESULTS In all contexts, independent of sex, genotype, or medial or lateral joint compartment, increased SBP thickness and SBP sclerostin expression were spatially associated with cartilage degeneration. Male TβRIIocy-/- mice, but not female TβRIIocy-/- mice, had increased cartilage degeneration, increased SBP thickness, and higher levels of SBP sclerostin compared with control mice (all P < 0.05), demonstrating that the role of osteocytic TGFβ signaling on joint homeostasis is sexually dimorphic. With changes in joint mechanics following injury, control mice had increased SBP thickness, subchondral bone volume, and SBP sclerostin expression (all P < 0.05). TβRIIocy-/- mice, however, were insensitive to subchondral bone changes with injury, suggesting that mechanosensation at the SBP requires osteocytic TGFβ signaling. CONCLUSION Our results provide new evidence that osteocytic TGFβ signaling is required for a mechanosensitive response to injury, and that osteocytes control SBP homeostasis to maintain cartilage health, identifying osteocytic TGFβ signaling as a novel therapeutic target for OA.
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Affiliation(s)
| | - Jeffrey Nguyen
- University of California, San Francisco, and California State University, Long Beach
| | | | | | - Alexis Dang
- University of California, San Francisco and San Francisco VAMC, San Francisco, California
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Dole NS, Yee CS, Schurman CA, Dallas SL, Alliston T. Assessment of Osteocytes: Techniques for Studying Morphological and Molecular Changes Associated with Perilacunar/Canalicular Remodeling of the Bone Matrix. Methods Mol Biol 2021; 2230:303-323. [PMID: 33197021 PMCID: PMC9165628 DOI: 10.1007/978-1-0716-1028-2_17] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Recent advances have revived interest in the concept of osteocyte perilacunar/canalicular remodeling (PLR) and have motivated efforts to identify the mechanisms regulating this process in bone in the context of normal physiology and pathological conditions. Here, we describe several methods that are evaluating morphological changes associated with PLR function of osteocytes.
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Affiliation(s)
- Neha S Dole
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, USA
| | - Cristal S Yee
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, USA
| | - Charles A Schurman
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, USA
- UC Berkeley/UCSF Graduate Program in Bioengineering, San Francisco, CA, USA
| | - Sarah L Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, Kansas City, MO, USA
| | - Tamara Alliston
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, USA.
- UC Berkeley/UCSF Graduate Program in Bioengineering, San Francisco, CA, USA.
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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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Hongo H, Hasegawa T, Saito M, Tsuboi K, Yamamoto T, Sasaki M, Abe M, Henrique Luiz de Freitas P, Yurimoto H, Udagawa N, Li M, Amizuka N. Osteocytic Osteolysis in PTH-treated Wild-type and Rankl-/- Mice Examined by Transmission Electron Microscopy, Atomic Force Microscopy, and Isotope Microscopy. J Histochem Cytochem 2020; 68:651-668. [PMID: 32942927 DOI: 10.1369/0022155420961375] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To demonstrate the ultrastructure of osteocytic osteolysis and clarify whether osteocytic osteolysis occurs independently of osteoclastic activities, we examined osteocytes and their lacunae in the femora and tibiae of 11-week-old male wild-type and Rankl-/- mice after injection of human parathyroid hormone (PTH) [1-34] (80 µg/kg/dose). Serum calcium concentration rose temporarily 1 hr after PTH administration in wild-type and Rankl-/- mice, when renal arteries and veins were ligated. After 6 hr, enlargement of osteocytic lacunae was evident in the cortical bones of wild-type and Rankl-/- mice, but not so in their metaphyses. Von Kossa staining and transmission electron microscopy showed broadly demineralized bone matrix peripheral to enlarged osteocytic lacunae, which contained fragmented collagen fibrils and islets of mineralized matrices. Nano-indentation by atomic force microscopy revealed the reduced elastic modulus of the PTH-treated osteocytic perilacunar matrix, despite the microscopic verification of mineralized matrix in that region. In addition, 44Ca deposition was detected by isotope microscopy and calcein labeling in the eroded osteocytic lacunae of wild-type and Rankl-/- mice. Taken together, our findings suggest that osteocytes can erode the bone matrix around them and deposit minerals on their lacunar walls independently of osteoclastic activity, at least in the murine cortical bone. (J Histochem Cytochem 68: -XXX, 2020).
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Affiliation(s)
- Hiromi Hongo
- Developmental Biology of Hard Tissue, Faculty of Dental Medicine, Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Tomoka Hasegawa
- Developmental Biology of Hard Tissue, Faculty of Dental Medicine, Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Masami Saito
- Bruker Japan K.K., Nano Surfaces & Metrology Division, Tokyo, Japan
| | - Kanako Tsuboi
- Dental Surgery, Haibara General Hospital, Makinohara, Japan
| | - Tomomaya Yamamoto
- Department of Dentistry, Japan Ground Self Defense Force Camp Asaka, Tokyo, Japan
| | - Muneteru Sasaki
- Department of Applied Prosthodontics, Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Miki Abe
- Developmental Biology of Hard Tissue, Faculty of Dental Medicine, Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
| | | | - Hisayoshi Yurimoto
- Isotope Imaging Laboratory, Creative Research Institution, Hokkaido University, Sapporo, Japan
| | - Nobuyuki Udagawa
- Department of Biochemistry, Matsumoto Dental University, Shiojiri, Japan
| | - Minqi Li
- Shandong Provincial Key Laboratory of Oral Biomedicine, School of Stomatology, Shandong University, Jinan, China
| | - Norio Amizuka
- Developmental Biology of Hard Tissue, Faculty of Dental Medicine, Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
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46
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Hashimoto R, Minoshima M, Kikuta J, Yari S, Bull SD, Ishii M, Kikuchi K. An Acid‐Activatable Fluorescence Probe for Imaging Osteocytic Bone Resorption Activity in Deep Bone Cavities. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202006388] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Ryu Hashimoto
- Graduate School of Engineering Osaka University 2-1 Yamadaoka Suita Osaka 565-0871 Japan
| | - Masafumi Minoshima
- Graduate School of Engineering Osaka University 2-1 Yamadaoka Suita Osaka 565-0871 Japan
| | - Junichi Kikuta
- Department of Immunology and Cell Biology Graduate School of Medicine and Frontier Biosciences Osaka University 2-2 Yamadaoka Suita Osaka 565-0871 Japan
- Immunology Frontier Research Center Osaka University 2-1 Yamadaoka Suita Osaka 565-0871 Japan
| | - Shinya Yari
- Department of Immunology and Cell Biology Graduate School of Medicine and Frontier Biosciences Osaka University 2-2 Yamadaoka Suita Osaka 565-0871 Japan
| | - Steven D. Bull
- Department of Chemistry University of Bath Claverton Down Bath BA2 7AY UK
| | - Masaru Ishii
- Department of Immunology and Cell Biology Graduate School of Medicine and Frontier Biosciences Osaka University 2-2 Yamadaoka Suita Osaka 565-0871 Japan
- Immunology Frontier Research Center Osaka University 2-1 Yamadaoka Suita Osaka 565-0871 Japan
| | - Kazuya Kikuchi
- Graduate School of Engineering Osaka University 2-1 Yamadaoka Suita Osaka 565-0871 Japan
- Immunology Frontier Research Center Osaka University 2-1 Yamadaoka Suita Osaka 565-0871 Japan
- Quantum Information and Quantum Biology Division Institute for Open and Transdisciplinary Research Initiatives Osaka University Suita Osaka 565-0871 Japan
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47
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Hashimoto R, Minoshima M, Kikuta J, Yari S, Bull SD, Ishii M, Kikuchi K. An Acid-Activatable Fluorescence Probe for Imaging Osteocytic Bone Resorption Activity in Deep Bone Cavities. Angew Chem Int Ed Engl 2020; 59:20996-21000. [PMID: 32744428 PMCID: PMC7692916 DOI: 10.1002/anie.202006388] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 06/24/2020] [Indexed: 01/13/2023]
Abstract
A rationally designed pH‐activatable fluorescent probe (pHocas‐RIS) has been used to measure localised pH levels in osteocytic lacunae in bone tissue. Conjugation of the moderate bone‐binding drug risedronate to a pH‐activatable BODIPY fluorophore enables the probe to penetrate osteocytic lacunae cavities that are embedded deep within the bone matrix. After injection of pHocas‐RIS, any osteocytic lacunae caused by bone‐resorbing osteocytes cause the probe to fluoresce in vivo, thus allowing imaging by intravital two‐photon excitation microscopy. This pH responsive probe enabled the visualization of the bone mineralizing activities of acid producing osteocytes in real time, thus allowing the study of their central role in remodeling the bone‐matrix in healthy and disease states.
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Affiliation(s)
- Ryu Hashimoto
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Masafumi Minoshima
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Junichi Kikuta
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.,Immunology Frontier Research Center, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Shinya Yari
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Steven D Bull
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Masaru Ishii
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.,Immunology Frontier Research Center, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Kazuya Kikuchi
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.,Immunology Frontier Research Center, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.,Quantum Information and Quantum Biology Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Suita, Osaka, 565-0871, Japan
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48
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Reznikov N, Hoac B, Buss DJ, Addison WN, Barros NMT, McKee MD. Biological stenciling of mineralization in the skeleton: Local enzymatic removal of inhibitors in the extracellular matrix. Bone 2020; 138:115447. [PMID: 32454257 DOI: 10.1016/j.bone.2020.115447] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/14/2020] [Accepted: 05/20/2020] [Indexed: 12/12/2022]
Abstract
Biomineralization is remarkably diverse and provides myriad functions across many organismal systems. Biomineralization processes typically produce hardened, hierarchically organized structures usually having nanostructured mineral assemblies that are formed through inorganic-organic (usually protein) interactions. Calcium‑carbonate biomineral predominates in structures of small invertebrate organisms abundant in marine environments, particularly in shells (remarkably it is also found in the inner ear otoconia of vertebrates), whereas calcium-phosphate biomineral predominates in the skeletons and dentitions of both marine and terrestrial vertebrates, including humans. Reconciliation of the interplay between organic moieties and inorganic crystals in bones and teeth is a cornerstone of biomineralization research. Key molecular determinants of skeletal and dental mineralization have been identified in health and disease, and in pathologic ectopic calcification, ranging from small molecules such as pyrophosphate, to small membrane-bounded matrix vesicles shed from cells, and to noncollagenous extracellular matrix proteins such as osteopontin and their derived bioactive peptides. Beyond partly knowing the regulatory role of the direct actions of inhibitors on vertebrate mineralization, more recently the importance of their enzymatic removal from the extracellular matrix has become increasingly understood. Great progress has been made in deciphering the relationship between mineralization inhibitors and the enzymes that degrade them, and how adverse changes in this physiologic pathway (such as gene mutations causing disease) result in mineralization defects. Two examples of this are rare skeletal diseases having osteomalacia/odontomalacia (soft bones and teeth) - namely hypophosphatasia (HPP) and X-linked hypophosphatemia (XLH) - where inactivating mutations occur in the gene for the enzymes tissue-nonspecific alkaline phosphatase (TNAP, TNSALP, ALPL) and phosphate-regulating endopeptidase homolog X-linked (PHEX), respectively. Here, we review and provide a concept for how existing and new information now comes together to describe the dual nature of regulation of mineralization - through systemic mineral ion homeostasis involving circulating factors, coupled with molecular determinants operating at the local level in the extracellular matrix. For the local mineralization events in the extracellular matrix, we present a focused concept in skeletal mineralization biology called the Stenciling Principle - a principle (building upon seminal work by Neuman and Fleisch) describing how the action of enzymes to remove tissue-resident inhibitors defines with precision the location and progression of mineralization.
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Affiliation(s)
- N Reznikov
- Object Research Systems Inc., 760 St. Paul West, Montreal, Quebec H3C 1M4, Canada.
| | - B Hoac
- Faculty of Dentistry, McGill University, 3640 University St., Montreal, Quebec H3A 0C7, Canada
| | - D J Buss
- Department of Anatomy and Cell Biology, McGill University, 3640 University St., Montreal, Quebec H3A 0C7, Canada
| | - W N Addison
- Department of Molecular Signaling and Biochemistry, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka, Japan
| | - N M T Barros
- Departamento de Biofísica, São Paulo, Departamento de Ciências Biológicas, Universidade Federal de São Paulo, Diadema, Brazil
| | - M D McKee
- Faculty of Dentistry, McGill University, 3640 University St., Montreal, Quebec H3A 0C7, Canada; Department of Anatomy and Cell Biology, McGill University, 3640 University St., Montreal, Quebec H3A 0C7, Canada.
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49
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Yang J, Ueharu H, Mishina Y. Energy metabolism: A newly emerging target of BMP signaling in bone homeostasis. Bone 2020; 138:115467. [PMID: 32512164 PMCID: PMC7423769 DOI: 10.1016/j.bone.2020.115467] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/29/2020] [Accepted: 06/01/2020] [Indexed: 12/11/2022]
Abstract
Energy metabolism is the process of generating energy (i.e. ATP) from nutrients. This process is indispensable for cell homeostasis maintenance and responses to varying conditions. Cells require energy for growth and maintenance and have evolved to have multiple pathways to produce energy. Both genetic and functional studies have demonstrated that energy metabolism, such as glucose, fatty acid, and amino acid metabolism, plays important roles in the formation and function of bone cells including osteoblasts, osteocytes, and osteoclasts. Dysregulation of energy metabolism in bone cells consequently disturbs the balance between bone formation and bone resorption. Metabolic diseases have also been reported to affect bone homeostasis. Bone morphogenic protein (BMP) signaling plays critical roles in regulating the formation and function of bone cells, thus affecting bone development and homeostasis. Mutations of BMP signaling-related genes in mice have been reported to show abnormalities in energy metabolism in many tissues, including bone. In addition, BMP signaling correlates with critical signaling pathways such as mTOR, HIF, Wnt, and self-degradative process autophagy to coordinate energy metabolism and bone homeostasis. These findings will provide a newly emerging target of BMP signaling and potential therapeutic strategies and the improved management of bone diseases. This review summarizes the recent advances in our understanding of (1) energy metabolism in regulating the formation and function of bone cells, (2) function of BMP signaling in whole body energy metabolism, and (3) mechanistic interaction of BMP signaling with other signaling pathways and biological processes critical for energy metabolism and bone homeostasis.
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Affiliation(s)
- Jingwen Yang
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, USA; The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory for Oral Biomedicine of Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei 430079, China.
| | - Hiroki Ueharu
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yuji Mishina
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, USA.
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50
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Dole NS, Yee CS, Mazur CM, Acevedo C, Alliston T. TGFβ Regulation of Perilacunar/Canalicular Remodeling Is Sexually Dimorphic. J Bone Miner Res 2020; 35:1549-1561. [PMID: 32282961 PMCID: PMC9126317 DOI: 10.1002/jbmr.4023] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 03/14/2020] [Accepted: 03/21/2020] [Indexed: 12/12/2022]
Abstract
Bone fragility is the product of defects in bone mass and bone quality, both of which show sex-specific differences. Despite this, the cellular and molecular mechanisms underpinning the sexually dimorphic control of bone quality remain unclear, limiting our ability to effectively prevent fractures, especially in postmenopausal osteoporosis. Recently, using male mice, we found that systemic or osteocyte-intrinsic inhibition of TGFβ signaling, achieved using the 9.6-kb DMP1 promoter-driven Cre recombinase (TβRIIocy-/- mice), suppresses osteocyte perilacunar/canalicular remodeling (PLR) and compromises bone quality. Because systemic TGFβ inhibition more robustly increases bone mass in female than male mice, we postulated that sex-specific differences in bone quality could likewise result, in part, from dimorphic regulation of PLR by TGFβ. Moreover, because lactation induces PLR, we examined the effect of TGFβ inhibition on the female skeleton during lactation. In contrast to males, female mice that possess an osteocyte-intrinsic defect in TGFβ signaling were protected from TGFβ-dependent defects in PLR and bone quality. The expression of requisite PLR enzymes, the lacunocanalicular network (LCN), and the flexural strength of female TβRIIocy-/- bone was intact. With lactation, however, bone loss and induction in PLR and osteocytic parathyroid hormone type I receptor (PTHR1) expression, were suppressed in TβRIIocy-/- bone, relative to the control littermates. Indeed, differential control of PTHR1 expression, by TGFβ and other factors, may contribute to dimorphism in PLR regulation in male and female TβRIIocy-/- mice. These findings provide key insights into the sex-based differences in osteocyte PLR that underlie bone quality and highlight TGFβ signaling as a crucial regulator of lactation-induced PLR. © 2020 American Society for Bone and Mineral Research.
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Affiliation(s)
- Neha S Dole
- Department of Orthopaedic Surgery, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Cristal S Yee
- Department of Orthopaedic Surgery, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Courtney M Mazur
- Department of Orthopaedic Surgery, University of California, San Francisco (UCSF), San Francisco, CA, USA.,University of California (UC) Berkeley-UCSF Graduate Program in Bioengineering, San Francisco, CA, USA
| | - Claire Acevedo
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Tamara Alliston
- Department of Orthopaedic Surgery, University of California, San Francisco (UCSF), San Francisco, CA, USA
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