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Abstract
Although osteoblasts and osteocytes are descended from the same lineage, they each have unique and essential roles in bone. Targeting gene deletion to osteoblasts and osteocytes using the Cre/loxP system has greatly increased our current understanding of how these cells function. Additionally, the use of the Cre/loxP system in conjunction with cell-specific reporters has enabled lineage tracing of these bone cells both in vivo and ex vivo. However, concerns have been raised regarding the specificity of the promoters used and the resulting off-target effects on cells within and outside of the bone. In this review, we have summarized the main mouse models that have been used to determine the functions of specific genes in osteoblasts and osteocytes. We discuss the expression patterns and specificity of the different promoter fragments during osteoblast to osteocyte differentiation in vivo. We also highlight how their expression in non-skeletal tissues may complicate the interpretation of study results. A thorough understanding of when and where these promoters are activated will enable improved study design and greater confidence in data interpretation.
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Affiliation(s)
- Y Kitase
- Indiana Center for Musculoskeletal Health, Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN 46202, United States of America
| | - M Prideaux
- Indiana Center for Musculoskeletal Health, Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN 46202, United States of America.
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Kalyanaraman H, China SP, Cabriales JA, Moininazeri J, Casteel DE, Garcia JJ, Wong VW, Chen A, Sah RL, Boss GR, Pilz RB. Protein Kinase G2 Is Essential for Skeletal Homeostasis and Adaptation to Mechanical Loading in Male but Not Female Mice. J Bone Miner Res 2023; 38:171-185. [PMID: 36371651 PMCID: PMC9825661 DOI: 10.1002/jbmr.4746] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 11/04/2022] [Accepted: 11/10/2022] [Indexed: 11/14/2022]
Abstract
We previously showed that the NO/cGMP/protein kinase G (PKG) signaling pathway positively regulates osteoblast proliferation, differentiation, and survival in vitro, and that cGMP-elevating agents have bone-anabolic effects in mice. Here, we generated mice with an osteoblast-specific (OB) knockout (KO) of type 2 PKG (gene name Prkg2) using a Col1a1(2.3 kb)-Cre driver. Compared to wild type (WT) littermates, 8-week-old male OB Prkg2-KO mice had fewer osteoblasts, reduced bone formation rates, and lower trabecular and cortical bone volumes. Female OB Prkg2-KO littermates showed no bone abnormalities, despite the same degree of PKG2 deficiency in bone. Expression of osteoblast differentiation- and Wnt/β-catenin-related genes was lower in primary osteoblasts and bones of male KO but not female KO mice compared to WT littermates. Osteoclast parameters were unaffected in both sexes. Since PKG2 is part of a mechano-sensitive complex in osteoblast membranes, we examined its role during mechanical loading. Cyclical compression of the tibia increased cortical thickness and induced mechanosensitive and Wnt/β-catenin-related genes to a similar extent in male and female WT mice and female OB Prkg2-KO mice, but loading had a minimal effect in male KO mice. We conclude that PKG2 drives bone acquisition and adaptation to mechanical loading via the Wnt/β-catenin pathway in male mice. The striking sexual dimorphism of OB Prkg2-KO mice suggests that current U.S. Food and Drug Administration-approved cGMP-elevating agents may represent novel effective treatment options for male osteoporosis. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Hema Kalyanaraman
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- These two authors contributed equally to the work
| | - Shyamsundar Pal China
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- These two authors contributed equally to the work
| | - Justin A. Cabriales
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jafar Moininazeri
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Darren E. Casteel
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Julian J. Garcia
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Van W. Wong
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Albert Chen
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Robert L. Sah
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Gerry R. Boss
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Renate B. Pilz
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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Li T, Wang H, Jiang Y, Guan Y, Chen S, Wu Z, Zou S, Bonewald LF, Duan P. Canonical Wnt/β-catenin signaling has positive effects on osteogenesis, but can have negative effects on cementogenesis. J Periodontol 2022; 93:1725-1737. [PMID: 35642884 DOI: 10.1002/jper.21-0599] [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: 10/15/2021] [Revised: 03/21/2022] [Accepted: 05/24/2022] [Indexed: 02/05/2023]
Abstract
BACKGROUND To date, therapeutic approaches for cementum regeneration are limited and outcomes remain unpredictable. A significant barrier to improve therapies for cementum regeneration is that the cementocyte and its intracellular signal transduction mechanisms remain poorly understood. This study aims to elucidate the regulatory mechanism of Wnt pathway in cementogenesis. METHODS The effects of canonical Wnt signaling were compared in vitro using immortalized murine cementocyte cell line IDG-CM6 and osteocyte cell line IDG-SW3 by qRT-PCR, Western blot, confocal microscopy, alkaline phosphatase (ALP) assay and Alizarin red S staining. In vivo, histological changes of cementum and bone formation were examined in transgenic mice in which constitutive activation of β-catenin is driven by Dmp1 promoter. RESULTS Expression of components of the Wnt/β-catenin pathway were much greater in the IDG-SW3 cells compared to the IDG-CM6 cells resulting in much lower expression of Sost/sclerostin in the IDG-SW3 cells. In the IDG-CM6 cells, low dose Wnt3a (20 ng/ml) had a modest effect while high dose (200 ng/ml) inhibited runt-related transcription factor 2 (Runx2), osterix (Osx), ALP and osteopontin (OPN) in contrast to the IDG-SW3 cells where high dose Wnt3a dramatically increased mRNA expression of these same markers. However, high Wnt3a significantly increased mRNA for components of Wnt/β-catenin signaling pathway in both IDG-CM6 and IDG-SW3 cells. In vivo, constitutive activation of β-catenin in the Dmp1-lineage cells in mice leads to bone hyperplasia and cementum hypoplasia. CONCLUSION(S) These findings indicate that Wnt signaling has distinct and different effects on the regulation of long bone as compared to cementum. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Tiancheng Li
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Han Wang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Yukun Jiang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Yuzhe Guan
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Shuo Chen
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Zuping Wu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Shujuan Zou
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Lynda Faye Bonewald
- Departments of Anatomy, Cell Biology & Physiology and Orthopaedic Surgery, Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Peipei Duan
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
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Garg P, Strigini M, Peurière L, Vico L, Iandolo D. The Skeletal Cellular and Molecular Underpinning of the Murine Hindlimb Unloading Model. Front Physiol 2021; 12:749464. [PMID: 34737712 PMCID: PMC8562483 DOI: 10.3389/fphys.2021.749464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/23/2021] [Indexed: 01/08/2023] Open
Abstract
Bone adaptation to spaceflight results in bone loss at weight bearing sites following the absence of the stimulus represented by ground force. The rodent hindlimb unloading model was designed to mimic the loss of mechanical loading experienced by astronauts in spaceflight to better understand the mechanisms causing this disuse-induced bone loss. The model has also been largely adopted to study disuse osteopenia and therefore to test drugs for its treatment. Loss of trabecular and cortical bone is observed in long bones of hindlimbs in tail-suspended rodents. Over the years, osteocytes have been shown to play a key role in sensing mechanical stress/stimulus via the ECM-integrin-cytoskeletal axis and to respond to it by regulating different cytokines such as SOST and RANKL. Colder experimental environments (~20-22°C) below thermoneutral temperatures (~28-32°C) exacerbate bone loss. Hence, it is important to consider the role of environmental temperatures on the experimental outcomes. We provide insights into the cellular and molecular pathways that have been shown to play a role in the hindlimb unloading and recommendations to minimize the effects of conditions that we refer to as confounding factors.
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Affiliation(s)
- Priyanka Garg
- INSERM, U1059 Sainbiose, Université Jean Monnet, Mines Saint-Étienne, Université de Lyon, Saint-Étienne, France
| | - Maura Strigini
- INSERM, U1059 Sainbiose, Université Jean Monnet, Mines Saint-Étienne, Université de Lyon, Saint-Étienne, France
| | - Laura Peurière
- INSERM, U1059 Sainbiose, Université Jean Monnet, Mines Saint-Étienne, Université de Lyon, Saint-Étienne, France
| | - Laurence Vico
- INSERM, U1059 Sainbiose, Université Jean Monnet, Mines Saint-Étienne, Université de Lyon, Saint-Étienne, France
| | - Donata Iandolo
- INSERM, U1059 Sainbiose, Université Jean Monnet, Mines Saint-Étienne, Université de Lyon, Saint-Étienne, France
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5
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Qin L, Liu W, Cao H, Xiao G. Molecular mechanosensors in osteocytes. Bone Res 2020; 8:23. [PMID: 32550039 PMCID: PMC7280204 DOI: 10.1038/s41413-020-0099-y] [Citation(s) in RCA: 197] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 04/07/2020] [Accepted: 04/17/2020] [Indexed: 12/11/2022] Open
Abstract
Osteocytes, the most abundant and long-lived cells in bone, are the master regulators of bone remodeling. In addition to their functions in endocrine regulation and calcium and phosphate metabolism, osteocytes are the major responsive cells in force adaptation due to mechanical stimulation. Mechanically induced bone formation and adaptation, disuse-induced bone loss and skeletal fragility are mediated by osteocytes, which sense local mechanical cues and respond to these cues in both direct and indirect ways. The mechanotransduction process in osteocytes is a complex but exquisite regulatory process between cells and their environment, between neighboring cells, and between different functional mechanosensors in individual cells. Over the past two decades, great efforts have focused on finding various mechanosensors in osteocytes that transmit extracellular mechanical signals into osteocytes and regulate responsive gene expression. The osteocyte cytoskeleton, dendritic processes, Integrin-based focal adhesions, connexin-based intercellular junctions, primary cilium, ion channels, and extracellular matrix are the major mechanosensors in osteocytes reported so far with evidence from both in vitro and in vitro studies. This review aims to give a systematic introduction to osteocyte mechanobiology, provide details of osteocyte mechanosensors, and discuss the roles of osteocyte mechanosensitive signaling pathways in the regulation of bone homeostasis.
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Affiliation(s)
- Lei Qin
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
| | - Wen Liu
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
| | - Huiling Cao
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
| | - Guozhi Xiao
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
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Tahimic CGT, Paul AM, Schreurs AS, Torres SM, Rubinstein L, Steczina S, Lowe M, Bhattacharya S, Alwood JS, Ronca AE, Globus RK. Influence of Social Isolation During Prolonged Simulated Weightlessness by Hindlimb Unloading. Front Physiol 2019; 10:1147. [PMID: 31572207 PMCID: PMC6753329 DOI: 10.3389/fphys.2019.01147] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 08/22/2019] [Indexed: 12/15/2022] Open
Abstract
The hindlimb unloading (HU) model has been used extensively to simulate the cephalad fluid shift and musculoskeletal disuse observed in spaceflight with its application expanding to study immune, cardiovascular and central nervous system responses, among others. Most HU studies are performed with singly housed animals, although social isolation also can substantially impact behavior and physiology, and therefore may confound HU experimental results. Other HU variants that allow for paired housing have been developed although no systematic assessment has been made to understand the effects of social isolation on HU outcomes. Hence, we aimed to determine the contribution of social isolation to tissue responses to HU. To accomplish this, we developed a refinement to the traditional NASA Ames single housing HU system to accommodate social housing in pairs, retaining desirable features of the original design. We conducted a 30-day HU experiment with adult, female mice that were either singly or socially housed. HU animals in both single and social housing displayed expected musculoskeletal deficits versus housing matched, normally loaded (NL) controls. However, select immune and hypothalamic-pituitary-adrenal (HPA) axis responses were differentially impacted by the HU social environment relative to matched NL controls. HU led to a reduction in % CD4+ T cells in singly housed, but not in socially housed mice. Unexpectedly, HU increased adrenal gland mass in socially housed but not singly housed mice, while social isolation increased adrenal gland mass in NL controls. HU also led to elevated plasma corticosterone levels at day 30 in both singly and socially housed mice. Thus, musculoskeletal responses to simulated weightlessness are similar regardless of social environment with a few differences in adrenal and immune responses. Our findings show that combined stressors can mask, not only exacerbate, select responses to HU. These findings further expand the utility of the HU model for studying possible combined effects of spaceflight stressors.
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Affiliation(s)
- Candice G T Tahimic
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,KBR, Houston, TX, United States
| | - Amber M Paul
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,Universities Space Research Association, Columbia, MD, United States
| | - Ann-Sofie Schreurs
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,KBR, Houston, TX, United States
| | - Samantha M Torres
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,Blue Marble Space Institute of Science, Seattle, WA, United States
| | - Linda Rubinstein
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,Universities Space Research Association, Columbia, MD, United States
| | - Sonette Steczina
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,Blue Marble Space Institute of Science, Seattle, WA, United States
| | - Moniece Lowe
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,Blue Marble Space Institute of Science, Seattle, WA, United States
| | - Sharmila Bhattacharya
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States
| | - Joshua S Alwood
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States
| | - April E Ronca
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,Department of Obstetrics and Gynecology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Ruth K Globus
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States
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Wang Y, Zhao W, Shi J, Wang J, Hao J, Pang X, Huang X, Chen X, Li Y, Jin R, Ge Q. Intestinal microbiota contributes to altered glucose metabolism in simulated microgravity mouse model. FASEB J 2019; 33:10140-10151. [DOI: 10.1096/fj.201900238rr] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Yifan Wang
- Department of ImmunologySchool of Basic Medical SciencesNHC Key Laboratory of Medical ImmunologyPeking University Beijing China
| | - Weijia Zhao
- Department of ImmunologySchool of Basic Medical SciencesNHC Key Laboratory of Medical ImmunologyPeking University Beijing China
| | - Junxiu Shi
- Department of Developmental Cell BiologyKey Laboratory of Cell BiologyMinistry of Public HealthKey Laboratory of Medical Cell BiologyMinistry of EducationChina Medical University Shenyang China
| | - Jiachi Wang
- Department of Developmental Cell BiologyKey Laboratory of Cell BiologyMinistry of Public HealthKey Laboratory of Medical Cell BiologyMinistry of EducationChina Medical University Shenyang China
| | - Jie Hao
- Department of ImmunologySchool of Basic Medical SciencesNHC Key Laboratory of Medical ImmunologyPeking University Beijing China
| | - Xuewen Pang
- Department of ImmunologySchool of Basic Medical SciencesNHC Key Laboratory of Medical ImmunologyPeking University Beijing China
| | - Xiaojun Huang
- Beijing Key Laboratory of Hematopoietic Stem Cell TransplantationPeking University People's HospitalInstitute of Hematology Beijing China
| | - Xiaoping Chen
- State Key Laboratory of Space Medicine Fundamentals and ApplicationChinese Astronaut Research and Training Center Beijing China
| | - Yongzhi Li
- State Key Laboratory of Space Medicine Fundamentals and ApplicationChinese Astronaut Research and Training Center Beijing China
| | - Rong Jin
- Department of ImmunologySchool of Basic Medical SciencesNHC Key Laboratory of Medical ImmunologyPeking University Beijing China
| | - Qing Ge
- Department of ImmunologySchool of Basic Medical SciencesNHC Key Laboratory of Medical ImmunologyPeking University Beijing China
- Department of Integration of Chinese and Western MedicineSchool of Basic Medical SciencesPeking University Beijing China
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Hemmatian H, Jalali R, Semeins CM, Hogervorst JMA, van Lenthe GH, Klein-Nulend J, Bakker AD. Mechanical Loading Differentially Affects Osteocytes in Fibulae from Lactating Mice Compared to Osteocytes in Virgin Mice: Possible Role for Lacuna Size. Calcif Tissue Int 2018; 103:675-685. [PMID: 30109376 PMCID: PMC6208961 DOI: 10.1007/s00223-018-0463-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 07/30/2018] [Indexed: 12/31/2022]
Abstract
Hormonal changes during lactation are associated with profound changes in bone cell biology, such as osteocytic osteolysis, resulting in larger lacunae. Larger lacuna shape theoretically enhances the transmission of mechanical signals to osteocytes. We aimed to provide experimental evidence supporting this theory by comparing the mechanoresponse of osteocytes in the bone of lactating mice, which have enlarged lacunae due to osteocytic osteolysis, with the response of osteocytes in bone from age-matched virgin mice. The osteocyte mechanoresponse was measured in excised fibulae that were cultured in hormone-free medium for 24 h and cyclically loaded for 10 min (sinusoidal compressive load, 3000 µε, 5 Hz) by quantifying loading-related changes in Sost mRNA expression (qPCR) and sclerostin and β-catenin protein expression (immunohistochemistry). Loading decreased Sost expression by ~ threefold in fibulae of lactating mice. The loading-induced decrease in sclerostin protein expression by osteocytes was larger in lactating mice (55% decrease ± 14 (± SD), n = 8) than virgin mice (33% decrease ± 15, n = 7). Mechanical loading upregulated β-catenin expression in osteocytes in lactating mice by 3.5-fold (± 0.2, n = 6) which is significantly (p < 0.01) higher than the 1.6-fold increase in β-catenin expression by osteocytes in fibulae from virgin mice (± 0.12, n = 4). These results suggest that osteocytes in fibulae from lactating mice with large lacunae may respond stronger to mechanical loading than those from virgin mice. This could indicate that osteocytes residing in larger lacuna show a stronger response to mechanical loading.
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Affiliation(s)
- Haniyeh Hemmatian
- Biomechanics Section, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Rozita Jalali
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Cornelis M Semeins
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Jolanda M A Hogervorst
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - G Harry van Lenthe
- Biomechanics Section, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Jenneke Klein-Nulend
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands.
| | - Astrid D Bakker
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
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9
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Bettis T, Kim BJ, Hamrick MW. Impact of muscle atrophy on bone metabolism and bone strength: implications for muscle-bone crosstalk with aging and disuse. Osteoporos Int 2018; 29:1713-1720. [PMID: 29777277 PMCID: PMC7861141 DOI: 10.1007/s00198-018-4570-1] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 03/28/2018] [Indexed: 02/07/2023]
Abstract
Bone fractures in older adults are often preceded by a loss of muscle mass and strength. Likewise, bone loss with prolonged bed rest, spinal cord injury, or with exposure to microgravity is also preceded by a rapid loss of muscle mass. Recent studies using animal models in the setting of hindlimb unloading or botulinum toxin (Botox) injection also reveal that muscle loss can induce bone loss. Moreover, muscle-derived factors such as irisin and leptin can inhibit bone loss with unloading, and knockout of catabolic factors in muscle such as the ubiquitin ligase Murf1 or the myokine myostatin can reduce osteoclastogenesis. These findings suggest that therapies targeting muscle in the setting of disuse atrophy may potentially attenuate bone loss, primarily by reducing bone resorption. These potential therapies not only include pharmacological approaches but also interventions such as whole-body vibration coupled with resistance exercise and functional electric stimulation of muscle.
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Affiliation(s)
- T Bettis
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Laney Walker Blvd. CB2915, Augusta, GA, 30912, USA
| | - B-J Kim
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Laney Walker Blvd. CB2915, Augusta, GA, 30912, USA
- ASAN Medical Center, College of Medicine, University of Ulsan, Seoul, Republic of Korea
| | - M W Hamrick
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Laney Walker Blvd. CB2915, Augusta, GA, 30912, USA.
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Yajima A, Tsuchiya K, Burr DB, Minner DE, Condon KW, Miller CA, Satoh S, Inaba M, Nakayama T, Tanizawa T, Ito A, Nitta K. Osteocytic perilacunar/canalicular turnover in hemodialysis patients with high and low serum PTH levels. Bone 2018; 113:68-76. [PMID: 29738853 DOI: 10.1016/j.bone.2018.05.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Revised: 04/16/2018] [Accepted: 05/02/2018] [Indexed: 01/30/2023]
Abstract
Osteocytic perilacunar/canalicular turnover in hemodialysis patients has not yet been reported. Osteocyte lacunae in lamellar bone and woven bone were classified as eroded surface-, osteoid surface-, and quiescent surface-predominant osteocyte lacunae (ES-Lc, OS-Lc, QS-Lc, respectively) in 55 hemodialysis patients with either high- (n = 45) or low- (n = 10) parathyroid hormone levels, and 19 control subjects without chronic kidney disease. We calculated the area and number of ES-Lc, OS-Lc, and QS-Lc. The mineralized surface on the osteocyte lacunar walls was measured in each group, and compared among the three groups. The shapes of the osteocyte lacunar walls were validated by backscattered electron microscopy. While the number of ES-Lc per bone area (N.ES-Lc/B.Ar) was higher than the number of OS-Lc per bone area (N.OS-Lc/B.Ar) in all groups, N.ES-Lc/B.Ar and N.OS-Lc/B.Ar were greater in high-parathyroid hormone group than in low-parathyroid hormone and control groups. The total volume of ES-Lc per bone area (ES-Lc.Ar/B.Ar) was greater than the total volume of OS-Lc per bone area (OS-Lc.Ar/B.Ar) in both parathyroid hormone groups. However, both lacunar erosion and lacunar formation increased proportionally, suggesting that global coupling between them was maintained. N.ES-Lc/B.Ar was higher in woven bone than in lamellar bone. The rate of OS-Lc stained by tetracycline hydrochloride, the mineralized lacunar surface and the mean area of OS-Lc with Tc obtained from both parathyroid hormone groups were greater than those in the control group. We conclude that osteocytic perilacunar/canalicular turnover is increased in hemodialysis patients with high parathyroid hormone levels. Osteocytic perilacunar/canalicular turnover depends, at least in part, on serum parathyroid hormone level. However, the ideal PTH level for osteocytic perilacunar/canalicular turnover could not be determined but osteocytic osteolysis was predominant in both the high- and low-PTH groups in this study. Thus, attention should be paid to bone loss from the viewpoint of osteocytic perilacunar/canalicular turnover in hemodialysis patients.
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Affiliation(s)
- Aiji Yajima
- Department of Anatomy and Cell Biology, Indiana University, School of Medicine, Indianapolis, IN, USA; Department of Medicine, Kidney Center, Tokyo Women's Medical University, Tokyo, Japan.
| | - Ken Tsuchiya
- Department of Blood Purification, Kidney Center, Tokyo Women's Medical University, Tokyo, Japan
| | - David B Burr
- Department of Anatomy and Cell Biology, Indiana University, School of Medicine, Indianapolis, IN, USA
| | - Daniel E Minner
- Department of Integrated Nanosystems Development Institute, Indiana University, Purdue University, Indianapolis, IN, USA
| | - Keith W Condon
- Department of Anatomy and Cell Biology, Indiana University, School of Medicine, Indianapolis, IN, USA
| | - Caroline A Miller
- Department of Anatomy and Cell Biology, Indiana University, School of Medicine, Indianapolis, IN, USA
| | - Shigeru Satoh
- Center for Kidney Disease and Transplantation, Akita University Hospital, Akita, Japan
| | - Masaaki Inaba
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan
| | | | | | - Akemi Ito
- Ito Bone Histomorphometry Institute, Niigata, Japan
| | - Kosaku Nitta
- Department of Medicine, Kidney Center, Tokyo Women's Medical University, Tokyo, Japan
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11
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Kitase Y, Vallejo JA, Gutheil W, Vemula H, Jähn K, Yi J, Zhou J, Brotto M, Bonewald LF. β-aminoisobutyric Acid, l-BAIBA, Is a Muscle-Derived Osteocyte Survival Factor. Cell Rep 2018; 22:1531-1544. [PMID: 29425508 PMCID: PMC5832359 DOI: 10.1016/j.celrep.2018.01.041] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 11/03/2017] [Accepted: 01/12/2018] [Indexed: 01/04/2023] Open
Abstract
Exercise has beneficial effects on metabolism and on tissues. The exercise-induced muscle factor β-aminoisobutyric acid (BAIBA) plays a critical role in the browning of white fat and in insulin resistance. Here we show another function for BAIBA, that of a bone-protective factor that prevents osteocyte cell death induced by reactive oxygen species (ROS). l-BAIBA was as or more protective than estrogen or N-acetyl cysteine, signaling through the Mas-Related G Protein-Coupled Receptor Type D (MRGPRD) to prevent the breakdown of mitochondria due to ROS. BAIBA supplied in drinking water prevented bone loss and loss of muscle function in the murine hindlimb unloading model, a model of osteocyte apoptosis. The protective effect of BAIBA was lost with age, not due to loss of the muscle capacity to produce BAIBA but likely to reduced Mrgprd expression with aging. This has implications for understanding the attenuated effect of exercise on bone with aging.
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Affiliation(s)
- Yukiko Kitase
- Department of Anatomy and Cell Biology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA.
| | - Julian A Vallejo
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA; Department of Oral & Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - William Gutheil
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Harika Vemula
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Katharina Jähn
- Department of Osteology and Biomechanics, University of Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jianxun Yi
- Kansas City University of Medicine and Bioscience, Kansas City, MO 64106, USA
| | - Jingsong Zhou
- Kansas City University of Medicine and Bioscience, Kansas City, MO 64106, USA
| | - Marco Brotto
- Bone-Muscle Collaborative Science, College of Nursing & Health Innovation, University of Texas-Arlington, Arlington, TX 76019, USA
| | - Lynda F Bonewald
- Department of Anatomy and Cell Biology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA; Department of Orthopaedic Surgery, School of Medicine, Indiana University, Indianapolis, IN 46202, USA.
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12
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Duan P, Bonewald LF. The role of the wnt/β-catenin signaling pathway in formation and maintenance of bone and teeth. Int J Biochem Cell Biol 2016; 77:23-29. [PMID: 27210503 DOI: 10.1016/j.biocel.2016.05.015] [Citation(s) in RCA: 238] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 02/05/2023]
Abstract
The Wnt signaling pathway is known as one of the important molecular cascades that regulate cell fate throughout lifespan. The Wnt signaling pathway is further separated into the canonical signaling pathway that depends on the function of β-catenin (Wnt/β-catenin pathway) and the noncanonical pathways that operate independently of β-catenin (planar cell polarity pathway and Wnt/Ca(2+) pathway). The Wnt/β-catenin signaling pathway is complex and consists of numerous receptors, inhibitors, activators, modulators, phosphatases, kinases and other components. However, there is one central, critical molecule to this pathway, β-catenin. While there are at least 3 receptors, LRP 4, 5 and 6, and over twenty activators known as the wnts, and several inhibitors such as sclerostin, dickkopf and secreted frizzled-related protein, these all target β-catenin. These regulators/modulators function to target β-catenin either to the proteasome for degradation or to the nucleus to regulate gene expression. Therefore, the interaction of β-catenin with different factors and Wnt/β-catenin signaling pathway will be the subject of this review with a focus on how this pathway relates to and functions in the formation and maintenance of bone and teeth based on mainly basic and pre-clinical research. Also in this review, the role of this pathway in osteocytes, bone cells embedded in the mineralized matrix, is covered in depth. This pathway is not only important in mineralized tissue growth and development, but for modulation of the skeleton in response to loading and unloading and the viability and health of the adult and aging skeleton.
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Affiliation(s)
- Peipei Duan
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - L F Bonewald
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA.
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