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Kelly MM, Sharma K, Wright CS, Yi X, Reyes Fernandez PC, Gegg AT, Gorrell TA, Noonan ML, Baghdady A, Sieger JA, Dolphin AC, Warden SJ, Deosthale P, Plotkin LI, Sankar U, Hum JM, Robling AG, Farach-Carson MC, Thompson WR. Loss of the auxiliary α 2δ 1 voltage-sensitive calcium channel subunit impairs bone formation and anabolic responses to mechanical loading. JBMR Plus 2024; 8:ziad008. [PMID: 38505532 PMCID: PMC10945727 DOI: 10.1093/jbmrpl/ziad008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 10/31/2023] [Accepted: 11/27/2023] [Indexed: 03/21/2024] Open
Abstract
Voltage-sensitive calcium channels (VSCCs) influence bone structure and function, including anabolic responses to mechanical loading. While the pore-forming (α1) subunit of VSCCs allows Ca2+ influx, auxiliary subunits regulate the biophysical properties of the pore. The α2δ1 subunit influences gating kinetics of the α1 pore and enables mechanically induced signaling in osteocytes; however, the skeletal function of α2δ1 in vivo remains unknown. In this work, we examined the skeletal consequences of deleting Cacna2d1, the gene encoding α2δ1. Dual-energy X-ray absorptiometry and microcomputed tomography imaging demonstrated that deletion of α2δ1 diminished bone mineral content and density in both male and female C57BL/6 mice. Structural differences manifested in both trabecular and cortical bone for males, while the absence of α2δ1 affected only cortical bone in female mice. Deletion of α2δ1 impaired skeletal mechanical properties in both sexes, as measured by three-point bending to failure. While no changes in osteoblast number or activity were found for either sex, male mice displayed a significant increase in osteoclast number, accompanied by increased eroded bone surface and upregulation of genes that regulate osteoclast differentiation. Deletion of α2δ1 also rendered the skeleton insensitive to exogenous mechanical loading in males. While previous work demonstrates that VSCCs are essential for anabolic responses to mechanical loading, the mechanism by which these channels sense and respond to force remained unclear. Our data demonstrate that the α2δ1 auxiliary VSCC subunit functions to maintain baseline bone mass and strength through regulation of osteoclast activity and also provides skeletal mechanotransduction in male mice. These data reveal a molecular player in our understanding of the mechanisms by which VSCCs influence skeletal adaptation.
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Affiliation(s)
- Madison M Kelly
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN 46202, United States
- College of Osteopathic Medicine, Marian University, Indianapolis, IN 46222, United States
| | - Karan Sharma
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN 46202, United States
- College of Osteopathic Medicine, Marian University, Indianapolis, IN 46222, United States
| | - Christian S Wright
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN 46202, United States
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN 46202, United States
| | - Xin Yi
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN 46202, United States
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN 46202, United States
| | - Perla C Reyes Fernandez
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN 46202, United States
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN 46202, United States
| | - Aaron T Gegg
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN 46202, United States
| | - Taylor A Gorrell
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN 46202, United States
| | - Megan L Noonan
- Department of Medical and Molecular Genetics, Indiana University, Indianapolis, IN 46202, United States
| | - Ahmed Baghdady
- College of Osteopathic Medicine, Marian University, Indianapolis, IN 46222, United States
| | - Jacob A Sieger
- College of Osteopathic Medicine, Marian University, Indianapolis, IN 46222, United States
| | - Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College of London, Gower Street, London WC1E 6BT, United Kingdom
| | - Stuart J Warden
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN 46202, United States
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN 46202, United States
- La Trobe Sport and Exercise Medicine Research Centre, La Trobe University, Melbourne Victoria 3086, DX 211319, Australia
| | - Padmini Deosthale
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN 46202, United States
- Department of Anatomy, Cell Biology, & Physiology, Indiana University, Indianapolis, IN 46202, United States
| | - Lilian I Plotkin
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN 46202, United States
- Department of Anatomy, Cell Biology, & Physiology, Indiana University, Indianapolis, IN 46202, United States
| | - Uma Sankar
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN 46202, United States
- Department of Anatomy, Cell Biology, & Physiology, Indiana University, Indianapolis, IN 46202, United States
| | - Julia M Hum
- College of Osteopathic Medicine, Marian University, Indianapolis, IN 46222, United States
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN 46202, United States
| | - Alexander G Robling
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN 46202, United States
- Department of Anatomy, Cell Biology, & Physiology, Indiana University, Indianapolis, IN 46202, United States
| | - Mary C Farach-Carson
- Department of Diagnostic & Biomedical Sciences, University of Texas Health Science Center at Houston School of Dentistry, Houston, TX 77054, United States
| | - William R Thompson
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN 46202, United States
- College of Osteopathic Medicine, Marian University, Indianapolis, IN 46222, United States
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN 46202, United States
- Department of Anatomy, Cell Biology, & Physiology, Indiana University, Indianapolis, IN 46202, United States
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Prideaux M, Smargiassi A, Peng G, Brotto M, Robling AG, Bonewald LF. L-BAIBA Synergizes with Sub-Optimal Mechanical Loading to Promote New Bone Formation. JBMR Plus 2023; 7:e10746. [PMID: 37283651 PMCID: PMC10241089 DOI: 10.1002/jbm4.10746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/21/2023] [Accepted: 03/28/2023] [Indexed: 06/08/2023] Open
Abstract
The L-enantiomer of β-aminoisobutyric acid (BAIBA) is secreted by contracted muscle in mice, and exercise increases serum levels in humans. In mice, L-BAIBA reduces bone loss with unloading, but whether it can have a positive effect with loading is unknown. Since synergism can be more easily observed with sub-optimal amounts of factors/stimulation, we sought to determine whether L-BAIBA could potentiate the effects of sub-optimal loading to enhance bone formation. L-BAIBA was provided in drinking water to C57Bl/6 male mice subjected to either 7 N or 8.25 N of sub-optimal unilateral tibial loading for 2 weeks. The combination of 8.25 N and L-BAIBA significantly increased the periosteal mineral apposition rate and bone formation rate compared to loading alone or BAIBA alone. Though L-BAIBA alone had no effect on bone formation, grip strength was increased, suggesting a positive effect on muscle function. Gene expression analysis of the osteocyte-enriched bone showed that the combination of L-BAIBA and 8.25 N induced the expression of loading-responsive genes such as Wnt1, Wnt10b, and the TGFb and BMP signaling pathways. One dramatic change was the downregulation of histone genes in response to sub-optimal loading and/or L-BAIBA. To determine early gene expression, the osteocyte fraction was harvested within 24 hours of loading. A dramatic effect was observed with L-BAIBA and 8.25 N loading as genes were enriched for pathways regulating the extracellular matrix (Chad, Acan, Col9a2), ion channel activity (Scn4b, Scn7a, Cacna1i), and lipid metabolism (Plin1, Plin4, Cidec). Few changes in gene expression were observed with sub-optimal loading or L-BAIBA alone after 24 hours. These results suggest that these signaling pathways are responsible for the synergistic effects between L-BAIBA and sub-optimal loading. Showing that a small muscle factor can enhance the effects of sub-optimal loading of bone may be of relevance for individuals unable to benefit from optimal exercise. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Matt Prideaux
- Indiana Center for Musculoskeletal Health, Department of Anatomy, Cell Biology and Physiology, School of MedicineIndiana UniversityIndianapolisINUSA
| | - Alberto Smargiassi
- Indiana Center for Musculoskeletal Health, Department of Anatomy, Cell Biology and Physiology, School of MedicineIndiana UniversityIndianapolisINUSA
| | - Gang Peng
- Indiana Center for Musculoskeletal Health, Department of Medicine and Molecular Genetics, School of MedicineIndiana UniversityIndianapolisINUSA
| | - Marco Brotto
- Bone‐Muscle Research Center, College of Nursing and Health InnovationUniversity of Texas‐ArlingtonArlingtonTXUSA
| | - Alexander G Robling
- Indiana Center for Musculoskeletal Health, Department of Anatomy, Cell Biology and Physiology, School of MedicineIndiana UniversityIndianapolisINUSA
| | - Lynda F Bonewald
- Indiana Center for Musculoskeletal Health, Department of Anatomy, Cell Biology and Physiology, School of MedicineIndiana UniversityIndianapolisINUSA
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H’ng CH, Khaladkar A, Rosello-Diez A. Look who's TORking: mTOR-mediated integration of cell status and external signals during limb development and endochondral bone growth. Front Cell Dev Biol 2023; 11:1153473. [PMID: 37152288 PMCID: PMC10154674 DOI: 10.3389/fcell.2023.1153473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 04/03/2023] [Indexed: 05/09/2023] Open
Abstract
The balance of cell proliferation and size is key for the control of organ development and repair. Moreover, this balance has to be coordinated within tissues and between tissues to achieve robustness in the organ's pattern and size. The tetrapod limb has been used to study these topics during development and repair, and several conserved pathways have emerged. Among them, mechanistic target of rapamycin (mTOR) signaling, despite being active in several cell types and developmental stages, is one of the least understood in limb development, perhaps because of its multiple potential roles and interactions with other pathways. In the body of this review, we have collated and integrated what is known about the role of mTOR signaling in three aspects of tetrapod limb development: 1) limb outgrowth; 2) chondrocyte differentiation after mesenchymal condensation and 3) endochondral ossification-driven longitudinal bone growth. We conclude that, given its ability to interact with the most common signaling pathways, its presence in multiple cell types, and its ability to influence cell proliferation, size and differentiation, the mTOR pathway is a critical integrator of external stimuli and internal status, coordinating developmental transitions as complex as those taking place during limb development. This suggests that the study of the signaling pathways and transcription factors involved in limb patterning, morphogenesis and growth could benefit from probing the interaction of these pathways with mTOR components.
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Affiliation(s)
- Chee Ho H’ng
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
| | - Ashwini Khaladkar
- Department of Biochemistry, Central University of Hyderabad, Hyderabad, India
| | - Alberto Rosello-Diez
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
- *Correspondence: Alberto Rosello-Diez, ,
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Li X, Kordsmeier J, Nookaew I, Kim HN, Xiong J. Piezo1 stimulates mitochondrial function via cAMP signaling. FASEB J 2022; 36:e22519. [PMID: 36052712 PMCID: PMC10167693 DOI: 10.1096/fj.202200300r] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 07/21/2022] [Accepted: 08/15/2022] [Indexed: 11/11/2022]
Abstract
Mechanical signals stimulate mitochondrial function but the molecular mechanisms are not clear. Here, we show that the mechanically sensitive ion channel Piezo1 plays a critical role in mitochondrial adaptation to mechanical stimulation. The activation of Piezo1 induced mitochondrial calcium uptake and oxidative phosphorylation (OXPHOS). In contrast, loss of Piezo1 reduced the mitochondrial oxygen consumption rate (OCR) and adenosine triphosphate (ATP) production in calvarial cells and these changes were associated with increased expression of the phosphodiesterases Pde4a and lower cyclic AMP (cAMP) levels. In addition, Piezo1 increased cAMP production and the activation of a cAMP-responsive transcriptional reporter. Consistent with this, cAMP was sufficient to increase mitochondrial OCR and the inhibition of phosphodiesterases augmented the increase in OCR induced by Piezo1. Moreover, the inhibition of cAMP production or activity of protein kinase A, a kinase activated by cAMP, prevented the increase in OCR induced by Piezo1. These results demonstrate that cAMP signaling contributes to the increase in mitochondrial OXPHOS induced by activation of Piezo1.
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Affiliation(s)
- Xuehua Li
- Department of Orthopaedic Surgery, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Center for Musculoskeletal Disease Research, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Jacob Kordsmeier
- Department of Orthopaedic Surgery, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Center for Musculoskeletal Disease Research, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Intawat Nookaew
- Center for Musculoskeletal Disease Research, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Ha-Neui Kim
- Center for Musculoskeletal Disease Research, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Jinhu Xiong
- Department of Orthopaedic Surgery, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Center for Musculoskeletal Disease Research, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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Yang JJ, Peng WX, Zhang MB. LncRNA KCNQ1OT1 promotes osteogenic differentiation via miR-205-5p/RICTOR axis. Exp Cell Res 2022; 415:113119. [PMID: 35341776 DOI: 10.1016/j.yexcr.2022.113119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 11/17/2022]
Abstract
Osteoporosis is a prevalent degenerative disease that is characterized by decreased bone density and strength, resulting in gradually increasing bone fragility. Osteoporosis is caused by an imbalance between osteoblastic bone formation and osteoclastic bone resorption. Recently, increasing evidence has suggested that long non-coding RNAs (lncRNAs) participate in the occurrence and development of osteoporosis. Herein, we explored the role of lncRNA KCNQ1OT1 in osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). QPCR results indicated that KCNQ1OT1 and RICTOR were down-regulated, while miR-205-5p was up-regulated in the osteoporotic patients, as compared with non-osteoporotic controls. During the osteogenic differentiation of BMSCs, the expression of KCNQ1OT1 and RICTOR was upregulated, whereas miR-205-5p was downregulated. The interaction among KCNQ1OT1, miR-205-5p and RICTOR was validated by dual luciferase reporter system. KCNQ1OT1 promoted RICTOR expression via inhibiting miR-205-5p, therefore promoting osteogenesis as demonstrated by ALP assay, alizarin red staining and the increased expression of osteogenic markers (OPN, RUNX2 and OCN). Furthermore, KCNQ1OT1 overexpression or miR-205-5p inhibition could promote ALP activity and mineralization of BMSCs, while overexpressed miR-205-5p could reverse the effects of overexpressed KCNQ1OT1, and knockdown of RICTOR could reverse the effects of miR-205-5p inhibition. In conclusion, our study illustrated that KCNQ1OT1 might inhibit miR-205-5p in BMSCs, thus upregulating the expression of RICTOR and promoting osteogenic differentiation.
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Affiliation(s)
- Jing-Jin Yang
- Department of Endocrinology, The First People's Hospital of Huaihua, HuaiHua, 418000, Hunan Province, PR China.
| | - Wei-Xia Peng
- Department of Endocrinology, Yiyang Central Hospital, YiYang, 413000, Hunan Province, PR China
| | - Mei-Biao Zhang
- Department of Endocrinology, The First People's Hospital of Huaihua, HuaiHua, 418000, Hunan Province, PR China
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Sen B, Xie Z, Howard S, Styner M, van Wijnen AJ, Uzer G, Rubin J. Mechanically Induced Nuclear Shuttling of β-Catenin Requires Co-transfer of Actin. Stem Cells 2022; 40:423-434. [PMID: 35278073 PMCID: PMC9633329 DOI: 10.1093/stmcls/sxac006] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 01/27/2022] [Indexed: 11/15/2022]
Abstract
Mesenchymal stem cells (MSCs) respond to environmental forces with both cytoskeletal re-structuring and activation of protein chaperones of mechanical information, β-catenin, and yes-associated protein 1 (YAP1). To function, MSCs must differentiate between dynamic forces such as cyclic strains of extracellular matrix due to physical activity and static strains due to ECM stiffening. To delineate how MSCs recognize and respond differently to both force types, we compared effects of dynamic (200 cycles × 2%) and static (1 × 2% hold) strain on nuclear translocation of β-catenin and YAP1 at 3 hours after force application. Dynamic strain induced nuclear accumulation of β-catenin, and increased cytoskeletal actin structure and cell stiffness, but had no effect on nuclear YAP1 levels. Critically, both nuclear actin and nuclear stiffness increased along with dynamic strain-induced β-catenin transport. Augmentation of cytoskeletal structure using either static strain or lysophosphatidic acid did not increase nuclear content of β-catenin or actin, but induced robust nuclear increase in YAP1. As actin binds β-catenin, we considered whether β-catenin, which lacks a nuclear localization signal, was dependent on actin to gain entry to the nucleus. Knockdown of cofilin-1 (Cfl1) or importin-9 (Ipo9), which co-mediate nuclear transfer of G-actin, prevented dynamic strain-mediated nuclear transfer of both β-catenin and actin. In sum, dynamic strain induction of actin re-structuring promotes nuclear transport of G-actin, concurrently supporting nuclear access of β-catenin via mechanisms used for actin transport. Thus, dynamic and static strain activate alternative mechanoresponses reflected by differences in the cellular distributions of actin, β-catenin, and YAP1.
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Affiliation(s)
- Buer Sen
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Zhihui Xie
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Sean Howard
- Department of Mechanical and Biomedical Engineering, Boise State University, Boise, ID, USA
| | - Maya Styner
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Andre J van Wijnen
- Department of Biochemistry, University of Vermont Medical School, Burlington, VT, USA
| | - Gunes Uzer
- Department of Mechanical and Biomedical Engineering, Boise State University, Boise, ID, USA
| | - Janet Rubin
- Corresponding author: Janet Rubin, Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA.
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Leser JM, Harriot A, Buck HV, Ward CW, Stains JP. Aging, Osteo-Sarcopenia, and Musculoskeletal Mechano-Transduction. FRONTIERS IN REHABILITATION SCIENCES 2021; 2:782848. [PMID: 36004321 PMCID: PMC9396756 DOI: 10.3389/fresc.2021.782848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/10/2021] [Indexed: 11/13/2022]
Abstract
The decline in the mass and function of bone and muscle is an inevitable consequence of healthy aging with early onset and accelerated decline in those with chronic disease. Termed osteo-sarcopenia, this condition predisposes the decreased activity, falls, low-energy fractures, and increased risk of co-morbid disease that leads to musculoskeletal frailty. The biology of osteo-sarcopenia is most understood in the context of systemic neuro-endocrine and immune/inflammatory alterations that drive inflammation, oxidative stress, reduced autophagy, and cellular senescence in the bone and muscle. Here we integrate these concepts to our growing understanding of how bone and muscle senses, responds and adapts to mechanical load. We propose that age-related alterations in cytoskeletal mechanics alter load-sensing and mechano-transduction in bone osteocytes and muscle fibers which underscores osteo-sarcopenia. Lastly, we examine the evidence for exercise as an effective countermeasure to osteo-sarcopenia.
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Affiliation(s)
| | | | | | | | - Joseph P. Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States
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Gould NR, Torre OM, Leser JM, Stains JP. The cytoskeleton and connected elements in bone cell mechano-transduction. Bone 2021; 149:115971. [PMID: 33892173 PMCID: PMC8217329 DOI: 10.1016/j.bone.2021.115971] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/30/2021] [Accepted: 04/17/2021] [Indexed: 02/07/2023]
Abstract
Bone is a mechano-responsive tissue that adapts to changes in its mechanical environment. Increases in strain lead to increased bone mass acquisition, whereas decreases in strain lead to a loss of bone mass. Given that mechanical stress is a regulator of bone mass and quality, it is important to understand how bone cells sense and transduce these mechanical cues into biological changes to identify druggable targets that can be exploited to restore bone cell mechano-sensitivity or to mimic mechanical load. Many studies have identified individual cytoskeletal components - microtubules, actin, and intermediate filaments - as mechano-sensors in bone. However, given the high interconnectedness and interaction between individual cytoskeletal components, and that they can assemble into multiple discreet cellular structures, it is likely that the cytoskeleton as a whole, rather than one specific component, is necessary for proper bone cell mechano-transduction. This review will examine the role of each cytoskeletal element in bone cell mechano-transduction and will present a unified view of how these elements interact and work together to create a mechano-sensor that is necessary to control bone formation following mechanical stress.
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Affiliation(s)
- Nicole R Gould
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Olivia M Torre
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jenna M Leser
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Joseph P Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA..
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Abstract
PURPOSE OF REVIEW Skeletal adaptation to mechanical loading plays a critical role in bone growth and the maintenance of bone homeostasis. Osteocytes are postulated to serve as a hub orchestrating bone remodeling. The recent findings on the molecular mechanisms by which osteocytes sense mechanical loads and the downstream bone-forming factors are reviewed. RECENT FINDINGS Calcium channels have been implicated in mechanotransduction in bone cells for a long time. Efforts have been made to identify a specific calcium channel mediating the skeletal response to mechanical loads. Recent studies have revealed that Piezo1, a mechanosensitive ion channel, is critical for normal bone growth and is essential for the skeletal response to mechanical loading. Identification of mechanosensors and their downstream effectors in mechanosensing bone cells is essential for new strategies to modulate regenerative responses and develop therapies to treat the bone loss related to disuse or advanced age.
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Affiliation(s)
- Xuehua Li
- Department of Orthopaedic Surgery, Center for Musculoskeletal Disease Research, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Jacob Kordsmeier
- Department of Orthopaedic Surgery, Center for Musculoskeletal Disease Research, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Jinhu Xiong
- Department of Orthopaedic Surgery, Center for Musculoskeletal Disease Research, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
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