1
|
Li H, Yu H, Liu D, Liao P, Gao C, Zhou J, Mei J, Zong Y, Ding P, Yao M, Wang B, Lu Y, Huang Y, Gao Y, Zhang C, Zheng M, Gao J. Adenosine diphosphate released from stressed cells triggers mitochondrial transfer to achieve tissue homeostasis. PLoS Biol 2024; 22:e3002753. [PMID: 39163396 PMCID: PMC11335167 DOI: 10.1371/journal.pbio.3002753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Accepted: 07/12/2024] [Indexed: 08/22/2024] Open
Abstract
Cell-to-cell mitochondrial transfer has recently been shown to play a role in maintaining physiological functions of cell. We previously illustrated that mitochondrial transfer within osteocyte dendritic network regulates bone tissue homeostasis. However, the mechanism of triggering this process has not been explored. Here, we showed that stressed osteocytes in mice release adenosine diphosphate (ADP), resulting in triggering mitochondrial transfer from healthy osteocytes to restore the oxygen consumption rate (OCR) and to alleviate reactive oxygen species accumulation. Furthermore, we identified that P2Y2 and P2Y6 transduced the ADP signal to regulate osteocyte mitochondrial transfer. We showed that mitochondrial metabolism is impaired in aged osteocytes, and there were more extracellular nucleotides release into the matrix in aged cortical bone due to compromised membrane integrity. Conditioned medium from aged osteocytes triggered mitochondrial transfer between osteocytes to enhance the energy metabolism. Together, using osteocyte as an example, this study showed new insights into how extracellular ADP triggers healthy cells to rescue energy metabolism crisis in stressed cells via mitochondrial transfer in tissue homeostasis.
Collapse
Affiliation(s)
- Hao Li
- Department of Orthopaedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hongping Yu
- Department of Orthopedic Surgery, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Delin Liu
- Department of Orthopaedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Peng Liao
- Department of Orthopaedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chuan Gao
- Department of Orthopaedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian Zhou
- Department of Orthopaedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jialun Mei
- Department of Orthopaedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yao Zong
- Centre for Orthopaedic Research, Medical School, The University of Western Australia, Nedlands, Australia
- Perron Institute for Neurological and Translational Science, Nedlands, Australia
| | - Peng Ding
- Department of Orthopaedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Meng Yao
- Department of Orthopaedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Bingqi Wang
- Department of Orthopaedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yafei Lu
- Department of Orthopaedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yigang Huang
- Department of Orthopaedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Youshui Gao
- Department of Orthopaedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Changqing Zhang
- Department of Orthopaedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Minghao Zheng
- Centre for Orthopaedic Research, Medical School, The University of Western Australia, Nedlands, Australia
- Perron Institute for Neurological and Translational Science, Nedlands, Australia
| | - Junjie Gao
- Department of Orthopaedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| |
Collapse
|
2
|
Vyavahare S, Ahluwalia P, Gupta SK, Kolhe R, Hill WD, Hamrick M, Isales CM, Fulzele S. The Role of Aryl Hydrocarbon Receptor in Bone Biology. Int J Tryptophan Res 2024; 17:11786469241246674. [PMID: 38757095 PMCID: PMC11097734 DOI: 10.1177/11786469241246674] [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] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 03/25/2024] [Indexed: 05/18/2024] Open
Abstract
Aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, is crucial in maintaining the skeletal system. Our study focuses on encapsulating the role of AhR in bone biology and identifying novel signaling pathways in musculoskeletal pathologies using the GEO dataset. The GEO2R analysis identified 8 genes (CYP1C1, SULT6B1, CYB5A, EDN1, CXCR4B, CTGFA, TIPARP, and CXXC5A) involved in the AhR pathway, which play a pivotal role in bone remodeling. The AhR knockout in hematopoietic stem cells showed alteration in several novel bone-related transcriptomes (eg, Defb14, ZNF 51, and Chrm5). Gene Ontology Enrichment Analysis demonstrated 54 different biological processes associated with bone homeostasis. Mainly, these processes include bone morphogenesis, bone development, bone trabeculae formation, bone resorption, bone maturation, bone mineralization, and bone marrow development. Employing Functional Annotation and Clustering through DAVID, we further uncovered the involvement of the xenobiotic metabolic process, p450 pathway, oxidation-reduction, and nitric oxide biosynthesis process in the AhR signaling pathway. The conflicting evidence of current research of AhR signaling on bone (positive and negative effects) homeostasis may be due to variations in ligand binding affinity, binding sites, half-life, chemical structure, and other unknown factors. In summary, our study provides a comprehensive understanding of the underlying mechanisms of the AhR pathway in bone biology.
Collapse
Affiliation(s)
- Sagar Vyavahare
- Department of Medicine, Augusta University, Augusta, GA, USA
| | | | | | - Ravindra Kolhe
- Department of Pathology, Augusta University, Augusta, GA, USA
| | - William D Hill
- Department of Pathology, Medical University of South Carolina, Charleston, SC, USA
| | - Mark Hamrick
- Department of Cell Biology and Anatomy, Augusta University, Augusta, GA, USA
- Center for Healthy Aging, Augusta University, Augusta, GA, USA
| | - Carlos M Isales
- Department of Medicine, Augusta University, Augusta, GA, USA
- Center for Healthy Aging, Augusta University, Augusta, GA, USA
| | - Sadanand Fulzele
- Department of Medicine, Augusta University, Augusta, GA, USA
- Department of Cell Biology and Anatomy, Augusta University, Augusta, GA, USA
- Center for Healthy Aging, Augusta University, Augusta, GA, USA
| |
Collapse
|
3
|
Wright CS, Lewis KJ, Semon K, Yi X, Reyes Fernandez PC, Rust K, Prideaux M, Schneider A, Pederson M, Deosthale P, Plotkin LI, Hum JM, Sankar U, Farach-Carson MC, Robling AG, Thompson WR. Deletion of the auxiliary α2δ1 voltage sensitive calcium channel subunit in osteocytes and late-stage osteoblasts impairs femur strength and load-induced bone formation in male mice. J Bone Miner Res 2024; 39:298-314. [PMID: 38477790 DOI: 10.1093/jbmr/zjae010] [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: 04/10/2023] [Revised: 12/03/2023] [Accepted: 12/27/2023] [Indexed: 03/14/2024]
Abstract
Osteocytes sense and respond to mechanical force by controlling the activity of other bone cells. However, the mechanisms by which osteocytes sense mechanical input and transmit biological signals remain unclear. Voltage-sensitive calcium channels (VSCCs) regulate calcium (Ca2+) influx in response to external stimuli. Inhibition or deletion of VSCCs impairs osteogenesis and skeletal responses to mechanical loading. VSCC activity is influenced by its auxiliary subunits, which bind the channel's α1 pore-forming subunit to alter intracellular Ca2+ concentrations. The α2δ1 auxiliary subunit associates with the pore-forming subunit via a glycosylphosphatidylinositol anchor and regulates the channel's calcium-gating kinetics. Knockdown of α2δ1 in osteocytes impairs responses to membrane stretch, and global deletion of α2δ1 in mice results in osteopenia and impaired skeletal responses to loading in vivo. Therefore, we hypothesized that the α2δ1 subunit functions as a mechanotransducer, and its deletion in osteocytes would impair skeletal development and load-induced bone formation. Mice (C57BL/6) with LoxP sequences flanking Cacna2d1, the gene encoding α2δ1, were crossed with mice expressing Cre under the control of the Dmp1 promoter (10 kb). Deletion of α2δ1 in osteocytes and late-stage osteoblasts decreased femoral bone quantity (P < .05) by DXA, reduced relative osteoid surface (P < .05), and altered osteoblast and osteocyte regulatory gene expression (P < .01). Cacna2d1f/f, Cre + male mice displayed decreased femoral strength and lower 10-wk cancellous bone in vivo micro-computed tomography measurements at the proximal tibia (P < .01) compared to controls, whereas Cacna2d1f/f, Cre + female mice showed impaired 20-wk cancellous and cortical bone ex vivo micro-computed tomography measurements (P < .05) vs controls. Deletion of α2δ1 in osteocytes and late-stage osteoblasts suppressed load-induced calcium signaling in vivo and decreased anabolic responses to mechanical loading in male mice, demonstrating decreased mechanosensitivity. Collectively, the α2δ1 auxiliary subunit is essential for the regulation of osteoid-formation, femur strength, and load-induced bone formation in male mice.
Collapse
Affiliation(s)
- Christian S Wright
- Department of Physical Therapy, School of Health and Rehabilitation Sciences, Indiana University, Indianapolis, IN 46202, United States
- Indiana Center for Musculoskeletal Health, Indianapolis, IN 46202, United States
| | - Karl J Lewis
- Department of Biomedical Engineering, Cornell University, Ithaca, NY 14850, United States
| | - Katelyn Semon
- Department of Physical Therapy, School of Health and Rehabilitation Sciences, Indiana University, Indianapolis, IN 46202, United States
- Department of Anatomy & Cell Biology, School of Medicine, Indiana University, Indianapolis, IN 46202, United States
| | - Xin Yi
- Department of Physical Therapy, School of Health and Rehabilitation Sciences, Indiana University, Indianapolis, IN 46202, United States
- Indiana Center for Musculoskeletal Health, Indianapolis, IN 46202, United States
| | - Perla C Reyes Fernandez
- Department of Physical Therapy, School of Health and Rehabilitation Sciences, Indiana University, Indianapolis, IN 46202, United States
- Indiana Center for Musculoskeletal Health, Indianapolis, IN 46202, United States
| | - Katie Rust
- Department of Physical Therapy, School of Health and Rehabilitation Sciences, Indiana University, Indianapolis, IN 46202, United States
| | - Matthew Prideaux
- Indiana Center for Musculoskeletal Health, Indianapolis, IN 46202, United States
| | - Artur Schneider
- Department of Physiology, College of Osteopathic Medicine, Marian University, Indianapolis, IN 46202, United States
| | - Molly Pederson
- School of Science, Indiana University-Purdue University, Indianapolis, IN 46202, United States
| | - Padmini Deosthale
- Department of Anatomy & Cell Biology, School of Medicine, Indiana University, Indianapolis, IN 46202, United States
| | - Lilian I Plotkin
- Indiana Center for Musculoskeletal Health, Indianapolis, IN 46202, United States
- Department of Anatomy & Cell Biology, School of Medicine, Indiana University, Indianapolis, IN 46202, United States
| | - Julia M Hum
- Department of Physiology, College of Osteopathic Medicine, Marian University, Indianapolis, IN 46202, United States
| | - Uma Sankar
- Indiana Center for Musculoskeletal Health, Indianapolis, IN 46202, United States
- Department of Anatomy & Cell Biology, School of Medicine, Indiana University, Indianapolis, IN 46202, United States
| | - Mary C Farach-Carson
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, University of Texas, Health Science Center, Houston, TX 78712, United States
| | - Alexander G Robling
- Indiana Center for Musculoskeletal Health, Indianapolis, IN 46202, United States
- Department of Anatomy & Cell Biology, School of Medicine, Indiana University, Indianapolis, IN 46202, United States
| | - William R Thompson
- Department of Physical Therapy, School of Health and Rehabilitation Sciences, Indiana University, Indianapolis, IN 46202, United States
- Indiana Center for Musculoskeletal Health, Indianapolis, IN 46202, United States
- Department of Anatomy & Cell Biology, School of Medicine, Indiana University, Indianapolis, IN 46202, United States
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Weiss N, Zamponi GW. The T-type calcium channelosome. Pflugers Arch 2024; 476:163-177. [PMID: 38036777 DOI: 10.1007/s00424-023-02891-z] [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: 10/27/2023] [Revised: 11/21/2023] [Accepted: 11/23/2023] [Indexed: 12/02/2023]
Abstract
T-type calcium channels perform crucial physiological roles across a wide spectrum of tissues, spanning both neuronal and non-neuronal system. For instance, they serve as pivotal regulators of neuronal excitability, contribute to cardiac pacemaking, and mediate the secretion of hormones. These functions significantly hinge upon the intricate interplay of T-type channels with interacting proteins that modulate their expression and function at the plasma membrane. In this review, we offer a panoramic exploration of the current knowledge surrounding these T-type channel interactors, and spotlight certain aspects of their potential for drug-based therapeutic intervention.
Collapse
Affiliation(s)
- Norbert Weiss
- Department of Pathophysiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic.
| | - Gerald W Zamponi
- Department of Clinical Neurosciences, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| |
Collapse
|
6
|
LaGuardia JS, Shariati K, Bedar M, Ren X, Moghadam S, Huang KX, Chen W, Kang Y, Yamaguchi DT, Lee JC. Convergence of Calcium Channel Regulation and Mechanotransduction in Skeletal Regenerative Biomaterial Design. Adv Healthc Mater 2023; 12:e2301081. [PMID: 37380172 PMCID: PMC10615747 DOI: 10.1002/adhm.202301081] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/20/2023] [Indexed: 06/30/2023]
Abstract
Cells are known to perceive their microenvironment through extracellular and intracellular mechanical signals. Upon sensing mechanical stimuli, cells can initiate various downstream signaling pathways that are vital to regulating proliferation, growth, and homeostasis. One such physiologic activity modulated by mechanical stimuli is osteogenic differentiation. The process of osteogenic mechanotransduction is regulated by numerous calcium ion channels-including channels coupled to cilia, mechanosensitive and voltage-sensitive channels, and channels associated with the endoplasmic reticulum. Evidence suggests these channels are implicated in osteogenic pathways such as the YAP/TAZ and canonical Wnt pathways. This review aims to describe the involvement of calcium channels in regulating osteogenic differentiation in response to mechanical loading and characterize the fashion in which those channels directly or indirectly mediate this process. The mechanotransduction pathway is a promising target for the development of regenerative materials for clinical applications due to its independence from exogenous growth factor supplementation. As such, also described are examples of osteogenic biomaterial strategies that involve the discussed calcium ion channels, calcium-dependent cellular structures, or calcium ion-regulating cellular features. Understanding the distinct ways calcium channels and signaling regulate these processes may uncover potential targets for advancing biomaterials with regenerative osteogenic capabilities.
Collapse
Affiliation(s)
- Jonnby S. LaGuardia
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Kaavian Shariati
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Meiwand Bedar
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Xiaoyan Ren
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
- Research Service, Greater Los Angeles VA Healthcare System, Los Angeles, CA, 91343, USA
| | - Shahrzad Moghadam
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Kelly X. Huang
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Wei Chen
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Youngnam Kang
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Dean T. Yamaguchi
- Research Service, Greater Los Angeles VA Healthcare System, Los Angeles, CA, 91343, USA
| | - Justine C. Lee
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
- Research Service, Greater Los Angeles VA Healthcare System, Los Angeles, CA, 91343, USA
- Department of Orthopaedic Surgery, Los Angeles, CA, 90095, USA
- UCLA Molecular Biology Institute, Los Angeles, CA, 90095, USA
| |
Collapse
|
7
|
Reyes Fernandez PC, Wright CS, Farach-Carson MC, Thompson WR. Examining Mechanisms for Voltage-Sensitive Calcium Channel-Mediated Secretion Events in Bone Cells. Calcif Tissue Int 2023; 113:126-142. [PMID: 37261463 PMCID: PMC11008533 DOI: 10.1007/s00223-023-01097-w] [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: 01/31/2023] [Accepted: 05/16/2023] [Indexed: 06/02/2023]
Abstract
In addition to their well-described functions in cell excitability, voltage-sensitive calcium channels (VSCCs) serve a critical role in calcium (Ca2+)-mediated secretion of pleiotropic paracrine and endocrine factors, including those produced in bone. Influx of Ca2+ through VSCCs activates intracellular signaling pathways to modulate a variety of cellular processes that include cell proliferation, differentiation, and bone adaptation in response to mechanical stimuli. Less well understood is the role of VSCCs in the control of bone and calcium homeostasis mediated through secreted factors. In this review, we discuss the various functions of VSCCs in skeletal cells as regulators of Ca2+ dynamics and detail how these channels might control the release of bioactive factors from bone cells. Because VSCCs are druggable, a better understanding of the multiple functions of these channels in the skeleton offers the opportunity for developing new therapies to enhance and maintain bone and to improve systemic health.
Collapse
Affiliation(s)
- Perla C Reyes Fernandez
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN, 46202, USA
- Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA
| | - Christian S Wright
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN, 46202, USA
- Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA
| | - Mary C Farach-Carson
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
- Departments of BioSciences and Bioengineering, Rice University, Houston, TX, 77005, USA
| | - William R Thompson
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN, 46202, USA.
- Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA.
- Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN, 46202, USA.
| |
Collapse
|
8
|
Reyes Fernandez PC, Wright CS, Masterson AN, Yi X, Tellman TV, Bonteanu A, Rust K, Noonan ML, White KE, Lewis KJ, Sankar U, Hum JM, Bix G, Wu D, Robling AG, Sardar R, Farach-Carson MC, Thompson WR. Gabapentin Disrupts Binding of Perlecan to the α 2δ 1 Voltage Sensitive Calcium Channel Subunit and Impairs Skeletal Mechanosensation. Biomolecules 2022; 12:biom12121857. [PMID: 36551284 PMCID: PMC9776037 DOI: 10.3390/biom12121857] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/04/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
Our understanding of how osteocytes, the principal mechanosensors within bone, sense and perceive force remains unclear. Previous work identified "tethering elements" (TEs) spanning the pericellular space of osteocytes and transmitting mechanical information into biochemical signals. While we identified the heparan sulfate proteoglycan perlecan (PLN) as a component of these TEs, PLN must attach to the cell surface to induce biochemical responses. As voltage-sensitive calcium channels (VSCCs) are critical for bone mechanotransduction, we hypothesized that PLN binds the extracellular α2δ1 subunit of VSCCs to couple the bone matrix to the osteocyte membrane. Here, we showed co-localization of PLN and α2δ1 along osteocyte dendritic processes. Additionally, we quantified the molecular interactions between α2δ1 and PLN domains and demonstrated for the first time that α2δ1 strongly associates with PLN via its domain III. Furthermore, α2δ1 is the binding site for the commonly used pain drug, gabapentin (GBP), which is associated with adverse skeletal effects when used chronically. We found that GBP disrupts PLN::α2δ1 binding in vitro, and GBP treatment in vivo results in impaired bone mechanosensation. Our work identified a novel mechanosensory complex within osteocytes composed of PLN and α2δ1, necessary for bone force transmission and sensitive to the drug GBP.
Collapse
Affiliation(s)
- Perla C. Reyes Fernandez
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN 46202, USA
| | - Christian S. Wright
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN 46202, USA
| | - Adrianna N. Masterson
- Department of Chemistry and Chemical Biology, School of Science, Indiana University, Indianapolis, IN 46202, USA
| | - Xin Yi
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN 46202, USA
| | - Tristen V. Tellman
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
| | - Andrei Bonteanu
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
- Department of Bioengineering, George R. Brown School of Engineering, Rice University, Houston, TX 77005, USA
| | - Katie Rust
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN 46202, USA
| | - Megan L. Noonan
- Department of Medical and Molecular Genetics, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - Kenneth E. White
- Department of Medical and Molecular Genetics, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - Karl J. Lewis
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Uma Sankar
- Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - Julia M. Hum
- Division of Biomedical Science, College of Osteopathic Medicine, Marian University, Indianapolis, IN 46222, USA
| | - Gregory Bix
- Departments of Neurosurgery and Neurology, School of Medicine, Tulane University, New Orleans, LA 70112, USA
| | - Danielle Wu
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
- Department of Bioengineering, George R. Brown School of Engineering, Rice University, Houston, TX 77005, USA
| | - Alexander G. Robling
- Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - Rajesh Sardar
- Department of Chemistry and Chemical Biology, School of Science, Indiana University, Indianapolis, IN 46202, USA
| | - Mary C. Farach-Carson
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
- Department of Bioengineering, George R. Brown School of Engineering, Rice University, Houston, TX 77005, USA
| | - William R. Thompson
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN 46202, USA
- Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
- Division of Biomedical Science, College of Osteopathic Medicine, Marian University, Indianapolis, IN 46222, USA
- Correspondence:
| |
Collapse
|
9
|
Reyes Fernandez PC, Wright CS, Warden SJ, Hum J, Farach-Carson MC, Thompson WR. Effects of Gabapentin and Pregabalin on Calcium Homeostasis: Implications for Physical Rehabilitation of Musculoskeletal Tissues. Curr Osteoporos Rep 2022; 20:365-378. [PMID: 36149592 PMCID: PMC10108402 DOI: 10.1007/s11914-022-00750-x] [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: 08/22/2022] [Indexed: 01/30/2023]
Abstract
PURPOSE OF REVIEW In this review, we discuss the mechanism of action of gabapentinoids and the potential consequences of long-term treatment with these drugs on the musculoskeletal system. RECENT FINDINGS Gabapentinoids, such as gabapentin (GBP) and pregabalin (PGB) were designed as antiepileptic reagents and are now commonly used as first-line treatment for neuropathic pain and increasingly prescribed off-label for other pain disorders such as migraines and back pain. GBP and PGB exert their analgesic actions by selectively binding the α2δ1 auxiliary subunit of voltage-sensitive calcium channels, thereby inhibiting channel function. Numerous tissues express the α2δ1 subunit where GBP and PGB can alter calcium-mediated signaling events. In tissues such as bone, muscle, and cartilage, α2δ1 has important roles in skeletal formation, mechanosensation, and normal tissue function/repair that may be affected by chronic use of gabapentinoids. Long-term use of gabapentinoids is associated with detrimental musculoskeletal outcomes, including increased fracture risk. Therefore, understanding potential complications is essential for clinicians to guide appropriate treatments.
Collapse
Affiliation(s)
- Perla C Reyes Fernandez
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN, 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA
| | - Christian S Wright
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN, 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA
| | - Stuart J Warden
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN, 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA
| | - Julia Hum
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA
- College of Osteopathic Medicine, Marian University, Indianapolis, IN, 4622, USA
| | - Mary C Farach-Carson
- Department of Diagnostic & Biomedical Sciences, University of Texas Health Science Center at Houston School of Dentistry, Houston, TX, 77054, USA
| | - William R Thompson
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN, 46202, USA.
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA.
- College of Osteopathic Medicine, Marian University, Indianapolis, IN, 4622, USA.
- Department of Anatomy and Cell Biology, Indiana University, Indianapolis, IN, 46202, USA.
| |
Collapse
|
10
|
Ahmed ASI, Sheng MHC, Lau KHW, Wilson SM, Wongworawat MD, Tang X, Ghahramanpouri M, Nehme A, Xu Y, Abdipour A, Zhang XB, Wasnik S, Baylink DJ. Calcium released by osteoclastic resorption stimulates autocrine/paracrine activities in local osteogenic cells to promote coupled bone formation. Am J Physiol Cell Physiol 2022; 322:C977-C990. [PMID: 35385325 PMCID: PMC9109806 DOI: 10.1152/ajpcell.00413.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A major cause of osteoporosis is impaired coupled bone formation. Mechanistically, both osteoclast-derived and bone-derived growth factors have been previously implicated. We hypothesize that the release of bone calcium during osteoclastic bone resorption is essential for coupled bone formation. Osteoclastic resorption increases interstitial fluid calcium locally from the normal 1.8 mM up to 5 mM. MC3T3-E1 osteoprogenitors, cultured in a 3.6 mM calcium medium, demonstrated that calcium signaling stimulated osteogenic cell proliferation, differentiation, and migration. Calcium channel knockdown studies implicated calcium channels, Cav1.2, store-operated calcium entry (SOCE), and calcium-sensing receptor (CaSR) in regulating bone cell anabolic activities. MC3T3-E1 cultured in a 3.6 mM calcium medium expressed increased gene expression of Wnt signaling and growth factors platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and bone morphogenic protein-2 (BMP 2). Our coupling model of bone formation, the Receptor activator of nuclear factor-kappa-Β ligand (RANKL) treated mouse calvaria, confirmed the role of calcium signaling in coupled bone formation by exhibiting increased gene expression for osterix and osteocalcin. Critically, dual immunocytochemistry showed that RANKL treatment increased osterix positive cells and increased fluorescence intensity of Cav1.2 and CaSR protein expression per osterix positive cell. The data established that calcium released by osteoclasts contributed to the regulation of coupled bone formation. CRISPR/Cas-9 knockout of Cav1.2 in osteoprogenitors cultured in basal calcium medium caused a >80% decrease in the expression of downstream osteogenic genes, emphasizing the large magnitude of the effect of calcium signaling. Thus, calcium signaling is a major regulator of coupled bone formation.
Collapse
Affiliation(s)
- Abu Shufian Ishtiaq Ahmed
- Department of Medicine, Division of Regenerative Medicine, Loma Linda University, Loma Linda, California, United States.,The Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - Matilda H C Sheng
- Department of Medicine, Division of Regenerative Medicine, Loma Linda University, Loma Linda, California, United States.,Musculoskeletal Disease Center, Jerry L. Pettis Memorial Veterans Affairs Medical Center, Loma Linda, California, United States
| | - Kin-Hing William Lau
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial Veterans Affairs Medical Center, Loma Linda, California, United States
| | - Sean M Wilson
- The Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - M Daniel Wongworawat
- Department of Orthopaedic Surgery, Loma Linda University, Loma Linda, California, United States
| | - Xiaolei Tang
- Department of Veterinary Biomedical Sciences, College of Veterinary Medicine, Long Island University, Brookville, NY, United States
| | - Mahdis Ghahramanpouri
- Department of Medicine, Division of Regenerative Medicine, Loma Linda University, Loma Linda, California, United States
| | - Antoine Nehme
- Department of Medicine, Division of Regenerative Medicine, Loma Linda University, Loma Linda, California, United States
| | - Yi Xu
- Department of Medicine, Division of Regenerative Medicine, Loma Linda University, Loma Linda, California, United States.,Division of Hematology and Oncology, Department of Medicine, Loma Linda University and Loma Linda University Cancer Center, Loma Linda, CA, United States
| | - Amir Abdipour
- Division of Nephrology, Department of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Xiao-Bing Zhang
- Department of Neurosurgery, Loma Linda University, Loma Linda, California, United States
| | - Samiksha Wasnik
- Department of Medicine, Division of Regenerative Medicine, Loma Linda University, Loma Linda, California, United States
| | - David J Baylink
- Department of Medicine, Division of Regenerative Medicine, Loma Linda University, Loma Linda, California, United States
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
Lewis KJ. Osteocyte calcium signaling - A potential translator of mechanical load to mechanobiology. Bone 2021; 153:116136. [PMID: 34339908 DOI: 10.1016/j.bone.2021.116136] [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: 02/18/2021] [Revised: 06/25/2021] [Accepted: 07/27/2021] [Indexed: 10/20/2022]
Abstract
Osteocytes are embedded dendritic bone cells; by virtue of their position in bone tissue, ability to coordinate bone building osteoblasts and resorbing osteoclasts, and sensitivity to tissue level mechanical loading, they serve as the resident bone mechanosensor. The mechanisms osteocytes use to change mechanical loading into biological signals that drive tissue level changes has been well studied over the last 30 years, however the ways loading parameters are encoded at the cellular level are still not fully understood. Calcium signaling is a first messenger signal exhibited by osteocytes in response to mechanical forces. A body of work interrogating the mechanisms of osteocyte calcium signaling exists and is presently expanding, presenting the opportunity to better understand the relationship between calcium signaling characteristics and tuned osteocyte responses to tissue level strain features (e.g. magnitude, duration, frequency). This review covers the history of osteocyte load induced calcium signaling and highlights potential cellular mechanisms used by osteocytes to turn details about loading parameters into biological events.
Collapse
Affiliation(s)
- Karl J Lewis
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States of America.
| |
Collapse
|
13
|
The mechanosensory and mechanotransductive processes mediated by ion channels and the impact on bone metabolism: A systematic review. Arch Biochem Biophys 2021; 711:109020. [PMID: 34461086 DOI: 10.1016/j.abb.2021.109020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 02/06/2023]
Abstract
Mechanical environments were associated with alterations in bone metabolism. Ion channels present on bone cells are indispensable for bone metabolism and can be directly or indirectly activated by mechanical stimulation. This review aimed to discuss the literature reporting the mechanical regulatory effects of ion channels on bone cells and bone tissue. An electronic search was conducted in PubMed, Embase and Web of Science. Studies about mechanically induced alteration of bone cells and bone tissue by ion channels were included. Ion channels including TRP family channels, Ca2+ release-activated Ca2+ channels (CRACs), Piezo1/2 channels, purinergic receptors, NMDA receptors, voltage-sensitive calcium channels (VSCCs), TREK2 potassium channels, calcium- and voltage-dependent big conductance potassium (BKCa) channels, small conductance, calcium-activated potassium (SKCa) channels and epithelial sodium channels (ENaCs) present on bone cells and bone tissue participate in the mechanical regulation of bone development in addition to contributing to direct or indirect mechanotransduction such as altered membrane potential and ionic flux. Physiological (beneficial) mechanical stimulation could induce the anabolism of bone cells and bone tissue through ion channels, but abnormal (harmful) mechanical stimulation could also induce the catabolism of bone cells and bone tissue through ion channels. Functional expression of ion channels is vital for the mechanotransduction of bone cells. Mechanical activation (opening) of ion channels triggers ion influx and induces the activation of intracellular modulators that can influence bone metabolism. Therefore, mechanosensitive ion channels provide new insights into therapeutic targets for the treatment of bone-related diseases such as osteopenia and aseptic implant loosening.
Collapse
|
14
|
Yao Y, Chu X, Ma M, Ye J, Wen Y, Li P, Cheng B, Cheng S, Zhang L, Liu L, Qi X, Liang C, Kafle OP, Wu C, Wang S, Wang X, Ning Y, Zhang F. Evaluate the effects of serum urate level on bone mineral density: a genome-wide gene-environment interaction analysis in UK Biobank cohort. Endocrine 2021; 73:702-711. [PMID: 34046847 DOI: 10.1007/s12020-021-02760-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 05/07/2021] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Serum urate is associated with BMD and may be a protective factor. However, the exact association and mechanism are still unclear. We performed a genome-wide gene-environmental interaction study (GWGEIS) to explore the interaction effects between gene and urate on BMD, using data from the UK Biobank cohort. METHODS A total of 4575 participants for femur total BMD, 4561 participants for L1-L4 BMD, and 237799 participants for heel BMD were included in the present study. Linear regression models were used to test for associations between urate and BMD (femur total BMD, L1-L4 BMD, heel BMD) by R software. GWGEIS was conducted by PLINK 2.0 using a generalize linear model, adjusted for age, sex, weight, smoking behavior, drinking behavior, physical activity and 10 principle components for population structure. RESULTS Results showed that urate was positively associated with femur total BMD, L1-L4 BMD and heel BMD and similar findings were observed in both the male and female subgroups. GWGEIS identified 261 genome-wide significant (P < 5.00 × 10-8) SNP × urate interaction effects for femur total BMD (rs8192585 in NOTCH4, rs116080577 in PBX1, rs9409991 in COL5A1), 17 genome-wide significant SNP × urate interaction effects for heel BMD (rs145344540 in PDE11A and rs78485379 in DKK2), 17 suggestive genome-wide SNP × urate interaction effects (P < 1.00 × 10-5) for L1-L4 BMD (rs10977015 in PTPRD). We also detected genome-wide significant and suggestive SNP × urate interaction effects for BMD in both the male and female subgroups. CONCLUSIONS This study reported several novel candidate genes, and strengthen the evidence of the interactive effects between gene and urate on the variations of BMD.
Collapse
Affiliation(s)
- Yao Yao
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Xiaomeng Chu
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Mei Ma
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Jing Ye
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Yan Wen
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Ping Li
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Bolun Cheng
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Shiqiang Cheng
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Lu Zhang
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Li Liu
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Xin Qi
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Chujun Liang
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Om Prakash Kafle
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Cuiyan Wu
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Sen Wang
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Xi Wang
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Yujie Ning
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Feng Zhang
- Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, School of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, China.
| |
Collapse
|
15
|
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.
Collapse
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..
| |
Collapse
|
16
|
Gardinier JD. The Diminishing Returns of Mechanical Loading and Potential Mechanisms that Desensitize Osteocytes. Curr Osteoporos Rep 2021; 19:436-443. [PMID: 34216359 PMCID: PMC9306018 DOI: 10.1007/s11914-021-00693-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/27/2021] [Indexed: 11/30/2022]
Abstract
Adaptation to mechanical loading is critical to maintaining bone mass and offers therapeutic potential to preventing age-related bone loss and osteoporosis. However, increasing the duration of loading is met with "diminishing returns" as the anabolic response quickly becomes saturated. As a result, the anabolic response to daily activities and repetitive bouts of loading is limited by the underlying mechanisms that desensitize and render bone unresponsive at the cellular level. Osteocytes are the primary cells that respond to skeletal loading and facilitate the overall anabolic response. Although many of osteocytes' signaling mechanisms activated in response to loading are considered anabolic in nature, several of them can also render osteocytes insensitive to further stimuli and thereby creating a negative feedback loop that limits osteocytes' overall response. The purpose of this review is to examine the potential mechanisms that may contribute to the loss of mechanosensitivity. In particular, we examined the inactivation/desensitization of ion channels and signaling molecules along with the potential role of endocytosis and cytoskeletal reorganization. The significance in defining the negative feedback loop is the potential to identify unique targets for enabling osteocytes to maintain their sensitivity. In doing so, we can begin to cultivate new strategies that capitalize on the anabolic nature of daily activities that repeatedly load the skeleton.
Collapse
|
17
|
Wright CS, Robling AG, Farach-Carson MC, Thompson WR. Skeletal Functions of Voltage Sensitive Calcium Channels. Curr Osteoporos Rep 2021; 19:206-221. [PMID: 33721180 PMCID: PMC8216424 DOI: 10.1007/s11914-020-00647-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/16/2020] [Indexed: 12/15/2022]
Abstract
Voltage-sensitive calcium channels (VSCCs) are ubiquitous multimeric protein complexes that are necessary for the regulation of numerous physiological processes. VSCCs regulate calcium influx and various intracellular processes including muscle contraction, neurotransmission, hormone secretion, and gene transcription, with function specificity defined by the channel's subunits and tissue location. The functions of VSCCs in bone are often overlooked since bone is not considered an electrically excitable tissue. However, skeletal homeostasis and adaptation relies heavily on VSCCs. Inhibition or deletion of VSCCs decreases osteogenesis, impairs skeletal structure, and impedes anabolic responses to mechanical loading. RECENT FINDINGS: While the functions of VSCCs in osteoclasts are less clear, VSCCs have distinct but complementary functions in osteoblasts and osteocytes. PURPOSE OF REVIEW: This review details the structure, function, and nomenclature of VSCCs, followed by a comprehensive description of the known functions of VSCCs in bone cells and their regulation of bone development, bone formation, and mechanotransduction.
Collapse
Affiliation(s)
- Christian S Wright
- Department of Physical Therapy, School of Health and Rehabilitation Sciences, Indiana University, Indianapolis, IN, 46202, USA
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA
| | - Alexander G Robling
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA
- Department of Anatomy & Cell Biology, Indiana University, Indianapolis, IN, 46202, USA
| | - Mary C Farach-Carson
- Department of Diagnostic & Biomedical Sciences, University of Texas Health Science Center at Houston School of Dentistry, Houston, TX, 77054, USA
| | - William R Thompson
- Department of Physical Therapy, School of Health and Rehabilitation Sciences, Indiana University, Indianapolis, IN, 46202, USA.
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis, IN, 46202, USA.
- Department of Anatomy & Cell Biology, Indiana University, Indianapolis, IN, 46202, USA.
| |
Collapse
|
18
|
Targeting Mechanotransduction in Osteosarcoma: A Comparative Oncology Perspective. Int J Mol Sci 2020; 21:ijms21207595. [PMID: 33066583 PMCID: PMC7589883 DOI: 10.3390/ijms21207595] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022] Open
Abstract
Mechanotransduction is the process in which cells can convert extracellular mechanical stimuli into biochemical changes within a cell. While this a normal process for physiological development and function in many organ systems, tumour cells can exploit this process to promote tumour progression. Here we summarise the current state of knowledge of mechanotransduction in osteosarcoma (OSA), the most common primary bone tumour, referencing both human and canine models and other similar mesenchymal malignancies (e.g., Ewing sarcoma). Specifically, we discuss the mechanical properties of OSA cells, the pathways that these cells utilise to respond to external mechanical cues, and mechanotransduction-targeting strategies tested in OSA so far. We point out gaps in the literature and propose avenues to address them. Understanding how the physical microenvironment influences cell signalling and behaviour will lead to the improved design of strategies to target the mechanical vulnerabilities of OSA cells.
Collapse
|
19
|
Lewis KJ, Yi X, Wright CS, Pemberton EZ, Bullock WA, Thompson WR, Robling AG. The mTORC2 Component Rictor Is Required for Load-Induced Bone Formation in Late-Stage Skeletal Cells. JBMR Plus 2020; 4:e10366. [PMID: 32666017 PMCID: PMC7340445 DOI: 10.1002/jbm4.10366] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 03/17/2020] [Indexed: 12/14/2022] Open
Abstract
Bone relies on mechanical cues to build and maintain tissue composition and architecture. Our understanding of bone cell mechanotransduction continues to evolve, with a few key signaling pathways emerging as vital. Wnt/β‐catenin, for example, is essential for proper anabolic response to mechanical stimulation. One key complex that regulates β‐catenin activity is the mammalian target of rapamycin complex 2 (mTORc2). mTORc2 is critical for actin cytoskeletal reorganization, an indispensable component in mechanotransduction in certain cell types. In this study, we probed the impact of the mTORc2 signaling pathway in osteocyte mechanotransduction by conditionally deleting the mTORc2 subunit Rictor in Dmp1‐expressing cells of C57BL/6 mice. Conditional deletion of the Rictor was achieved using the Dmp1–Cre driver to recombine Rictor floxed alleles. Rictor mutants exhibited a decrease in skeletal properties, as measured by DXA, μCT, and mechanical testing, compared with Cre‐negative floxed littermate controls. in vivo axial tibia loading conducted in adult mice revealed a deficiency in the osteogenic response to loading among Rictor mutants. Histological measurements of osteocyte morphology indicated fewer, shorter cell processes in Rictor mutants, which might explain the compromised response to mechanical stimulation. In summary, inhibition of the mTORc2 pathway in late osteoblasts/osteocytes leads to decreased bone mass and mechanically induced bone formation. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.
Collapse
Affiliation(s)
- Karl J Lewis
- Department of Anatomy & Cell Biology Indiana University School of Medicine Indianapolis IN USA
| | - Xin Yi
- Department of Physical Therapy Indiana University School of Health & Human Sciences Indianapolis IN USA
| | - Christian S Wright
- Department of Physical Therapy Indiana University School of Health & Human Sciences Indianapolis IN USA
| | - Emily Z Pemberton
- Department of Anatomy & Cell Biology Indiana University School of Medicine Indianapolis IN USA
| | - Whitney A Bullock
- Department of Anatomy & Cell Biology Indiana University School of Medicine Indianapolis IN USA
| | - William R Thompson
- Department of Physical Therapy Indiana University School of Health & Human Sciences Indianapolis IN USA.,Indiana Center for Musculoskeletal Health Indianapolis IN USA
| | - Alexander G Robling
- Department of Anatomy & Cell Biology Indiana University School of Medicine Indianapolis IN USA.,Indiana Center for Musculoskeletal Health Indianapolis IN USA.,Department of Biomedical Engineering Indiana University-Purdue University at Indianapolis Indianapolis IN USA.,Richard L. Roudebush VA Medical Center Indianapolis IN USA
| |
Collapse
|
20
|
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.
Collapse
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
| |
Collapse
|
21
|
Pei S, Parthasarathy S, Parajuli A, Martinez J, Lv M, Jiang S, Wu D, Wei S, Lu XL, Farach-Carson MC, Kirn-Safran CB, Wang L. Perlecan/Hspg2 deficiency impairs bone's calcium signaling and associated transcriptome in response to mechanical loading. Bone 2020; 131:115078. [PMID: 31715337 PMCID: PMC6945981 DOI: 10.1016/j.bone.2019.115078] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 09/24/2019] [Accepted: 09/24/2019] [Indexed: 10/25/2022]
Abstract
Perlecan, a heparan sulfate proteoglycan, acts as a mechanical sensor for bone to detect external loading. Deficiency of perlecan increases the risk of osteoporosis in patients with Schwartz-Jampel Syndrome (SJS) and attenuates loading-induced bone formation in perlecan deficient mice (Hypo). Considering that intracellular calcium [Ca2+]i is an ubiquitous messenger controlling numerous cellular processes including mechanotransduction, we hypothesized that perlecan deficiency impairs bone's calcium signaling in response to loading. To test this, we performed real-time [Ca2+]i imaging on in situ osteocytes of adult murine tibiae under cyclic loading (8N). Relative to wild type (WT), Hypo osteocytes showed decreases in the overall [Ca2+]i response rate (-58%), calcium peaks (-33%), cells with multiple peaks (-53%), peak magnitude (-6.8%), and recovery speed to baseline (-23%). RNA sequencing and pathway analysis of tibiae from mice subjected to one or seven days of unilateral loading demonstrated that perlecan deficiency significantly suppressed the calcium signaling, ECM-receptor interaction, and focal adhesion pathways following repetitive loading. Defects in the endoplasmic reticulum (ER) calcium cycling regulators such as Ryr1/ryanodine receptors and Atp2a1/Serca1 calcium pumps were identified in Hypo bones. Taken together, impaired calcium signaling may contribute to bone's reduced anabolic response to loading, underlying the osteoporosis risk for the SJS patients.
Collapse
Affiliation(s)
- Shaopeng Pei
- Center for Biomechanical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
| | | | - Ashutosh Parajuli
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19716, United States
| | - Jerahme Martinez
- Center for Biomechanical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
| | - Mengxi Lv
- Center for Biomechanical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
| | - Sida Jiang
- Center for Biomechanical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
| | - Danielle Wu
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, University of Texas Health Science Center, Houston, TX 77054, United States
| | - Shuo Wei
- Center for Biomechanical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
| | - X Lucas Lu
- Center for Biomechanical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
| | - Mary C Farach-Carson
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, University of Texas Health Science Center, Houston, TX 77054, United States
| | - Catherine B Kirn-Safran
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States; Department of Biology, Widener University, Chester, PA 19013, United States
| | - Liyun Wang
- Center for Biomechanical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States; Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States; Department of Biomedical Engineering, University of Delaware, Newark, DE 19716, United States.
| |
Collapse
|
22
|
Alfieri R, Vassalli M, Viti F. Flow-induced mechanotransduction in skeletal cells. Biophys Rev 2019; 11:729-743. [PMID: 31529361 DOI: 10.1007/s12551-019-00596-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/03/2019] [Indexed: 12/15/2022] Open
Abstract
Human body is subject to many and variegated mechanical stimuli, actuated in different ranges of force, frequency, and duration. The process through which cells "feel" forces and convert them into biochemical cascades is called mechanotransduction. In this review, the effects of fluid shear stress on bone cells will be presented. After an introduction to present the major players in bone system, we describe the mechanoreceptors in bone tissue that can feel and process fluid flow. In the second part of the review, we present an overview of the biological processes and biochemical cascades initiated by fluid shear stress in bone cells.
Collapse
Affiliation(s)
- Roberta Alfieri
- Institute of Molecular Genetics "Luigi Luca Cavalli-Sforza" - National Research Council (IGM-CNR), Via Abbiategrasso, 207, 27100, Pavia, Italy
| | - Massimo Vassalli
- Institute of Biophysics - National Research Council (IBF-CNR), Via De Marini, 6, 16149, Genoa, Italy
| | - Federica Viti
- Institute of Biophysics - National Research Council (IBF-CNR), Via De Marini, 6, 16149, Genoa, Italy.
| |
Collapse
|
23
|
The effect of P2X7R-mediated Ca 2+ signaling in OPG-induced osteoclasts adhesive structure damage. Exp Cell Res 2019; 383:111555. [PMID: 31415763 DOI: 10.1016/j.yexcr.2019.111555] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 08/09/2019] [Accepted: 08/10/2019] [Indexed: 11/21/2022]
Abstract
Osteoclast adhesion is important for bone resorption. Osteoprotegerin inhibits osteoclast differentiation and bone resorption via Ca2+ signaling. Purinergic receptor P2X7 (P2X7R) affects osteoclastogenesis by activating transcription factor nuclear factor of activated T cells 1 (NFATc1). However, the detailed mechanism of osteoprotegerin-mediated P2X7R modulation of osteoclast adhesion is unclear. This study aimed to determine the effect of P2X7R on osteoprotegerin-induced damage to osteoclast adhesion. Osteoprotegerin reduced the expression of P2X7R, and protein tyrosine kinase 2 (PYK2) and SRC phosphorylation, and reduced calcium concentration, significantly decreasing Ca2+-NFATc1 signaling. 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxymethyl ester) (BAPTA-AM)/N-(6-Aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7) partly or absolutely recovered osteoprotegerin-induced osteoclasts adhesion structure damage, including increased the PYK2 and SRC phosphorylation, changed the distribution of PYK2/SRC and integrinαvβ3, and inhibited retraction of lamellipodia and filopodia and recovered osteoclast bone resorption activity. In addition, BAPTA-AM/W-7 also increased osteoprotegerin-induced activation of Ca2+-NFATc1 signaling, and restored normal P2X7R levels. P2X7R knockdown significantly inhibited osteoclast differentiation, and the formation of lamellipodia and filopodia, reduced the PYK2 and SRC phosphorylation, and inhibited Ca2+-related protein activation. However, P2X7R knockdown aggravated osteoprotegerin-induced osteoclast adhesion damage via Ca2+ signaling. In conclusion, the P2X7R-Ca2+ NFATc1 signaling pathway has a key functional role in osteoprotegerin-induced osteoclast adhesion structure damage.
Collapse
|
24
|
Imai M, Ayukawa Y, Yasunami N, Furuhashi A, Takemura Y, Adachi N, Hu J, Zhou X, Moriyama Y, Atsuta I, Kurata K, Koyano K. Effect of a Single Injection of Benidipine-Impregnated Biodegradable Microcarriers on Bone and Gingival Healing at the Tooth Extraction Socket. Adv Wound Care (New Rochelle) 2019; 8:108-117. [PMID: 30911442 DOI: 10.1089/wound.2018.0834] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 09/17/2018] [Indexed: 11/12/2022] Open
Abstract
Objective: A dihydropyridine-type calcium channel blocker, benidipine (BD), is extensively used in hypertension therapy. In vitro study reported BD promoting bone metabolism. We evaluated the effect of sustained release of BD-loaded poly(lactic-co-glycolic acid) (PLGA) microcarriers on the promotion of bone and gingival healing at an extraction socket in vivo. In addition, the effect of BD on osteoblasts, osteocytes, fibroblasts, and epithelial cells was evaluated in vitro. Approach: The maxillary first molar of rats was extracted. Next, PLGA microcarriers containing BD were directly injected into the gingivobuccal fold as a single dose. After injection, bone and soft-tissue healing was histologically evaluated. Effect of BD on proliferation, migration, and gene expression of gingival and bone cell was also examined in vitro. Results: After tooth extraction, BD significantly augmented bone volume and density, and also epithelial wound healing. During in vitro studies, BD promoted significant proliferation and migration of fibroblasts and epithelial cells. Real-time RT-PCR revealed that BD upregulated messenger RNA expression of Ahsg (alpha 2-HS glycoprotein) and Csf2 (colony-stimulating factor 2) in osteoblasts. Innovation: The prevention of bone and soft-tissue reduction associated with tooth extraction has been eagerly anticipated in the field of dentistry. This study first reported the effect of BD on extraction socket healing. Conclusion: A single dose of topically administered BD-loaded PLGA microcarriers promoted bone and soft-tissue healing at the extraction site of tooth.
Collapse
Affiliation(s)
- Mikio Imai
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Yasunori Ayukawa
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Noriyuki Yasunami
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Akihiro Furuhashi
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Yoko Takemura
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Naomi Adachi
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Jiangqi Hu
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Xudiyang Zhou
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Yasuko Moriyama
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Ikiru Atsuta
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Kosaku Kurata
- Department of Mechanical Engineering, Faculty of Engineering Kyushu University, Fukuoka, Japan
| | - Kiyoshi Koyano
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| |
Collapse
|
25
|
Huang X, Das R, Patel A, Nguyen TD. Physical Stimulations for Bone and Cartilage Regeneration. REGENERATIVE ENGINEERING AND TRANSLATIONAL MEDICINE 2018; 4:216-237. [PMID: 30740512 PMCID: PMC6366645 DOI: 10.1007/s40883-018-0064-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Accepted: 06/07/2018] [Indexed: 12/26/2022]
Abstract
A wide range of techniques and methods are actively invented by clinicians and scientists who are dedicated to the field of musculoskeletal tissue regeneration. Biological, chemical, and physiological factors, which play key roles in musculoskeletal tissue development, have been extensively explored. However, physical stimulation is increasingly showing extreme importance in the processes of osteogenic and chondrogenic differentiation, proliferation and maturation through defined dose parameters including mode, frequency, magnitude, and duration of stimuli. Studies have shown manipulation of physical microenvironment is an indispensable strategy for the repair and regeneration of bone and cartilage, and biophysical cues could profoundly promote their regeneration. In this article, we review recent literature on utilization of physical stimulation, such as mechanical forces (cyclic strain, fluid shear stress, etc.), electrical and magnetic fields, ultrasound, shock waves, substrate stimuli, etc., to promote the repair and regeneration of bone and cartilage tissue. Emphasis is placed on the mechanism of cellular response and the potential clinical usage of these stimulations for bone and cartilage regeneration.
Collapse
|
26
|
Arteaga-Tlecuitl R, Sanchez-Sandoval AL, Ramirez-Cordero BE, Rosendo-Pineda MJ, Vaca L, Gomora JC. Increase of Ca V3 channel activity induced by HVA β1b-subunit is not mediated by a physical interaction. BMC Res Notes 2018; 11:810. [PMID: 30428904 PMCID: PMC6236959 DOI: 10.1186/s13104-018-3917-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/09/2018] [Indexed: 01/13/2023] Open
Abstract
Objective Low voltage-activated (LVA) calcium channels are crucial for regulating oscillatory behavior in several types of neurons and other excitable cells. LVA channels dysfunction has been implicated in epilepsy, neuropathic pain, cancer, among other diseases. Unlike for High Voltage-Activated (HVA) channels, voltage-dependence and kinetics of currents carried by recombinant LVA, i.e., CaV3 channels, are quite similar to those observed in native currents. Therefore, whether these channels are regulated by HVA auxiliary subunits, remain controversial. Here, we used the α1-subunits of CaV3.1, CaV3.2, and CaV3.3 channels, together with HVA auxiliary β-subunits to perform electrophysiological, confocal microscopy and immunoprecipitation experiments, in order to further explore this possibility. Results Functional expression of CaV3 channels is up-regulated by all four β-subunits, although most consistent effects were observed with the β1b-subunit. The biophysical properties of CaV3 channels were not modified by any β-subunit. Furthermore, although β1b-subunits increased colocalization of GFP-tagged CaV3 channels and the plasma membrane of HEK-293 cells, western blots analysis revealed the absence of physical interaction between CaV3.3 and β1b-subunits as no co-immunoprecipitation was observed. These results provide solid evidence that the up-regulation of LVA channels in the presence of HVA-β1b subunit is not mediated by a high affinity interaction between both proteins. Electronic supplementary material The online version of this article (10.1186/s13104-018-3917-1) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Rogelio Arteaga-Tlecuitl
- Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
| | - Ana Laura Sanchez-Sandoval
- Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
| | - Belen Ernestina Ramirez-Cordero
- Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
| | - Margarita Jacaranda Rosendo-Pineda
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
| | - Luis Vaca
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
| | - Juan Carlos Gomora
- Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico.
| |
Collapse
|
27
|
Mikolajewicz N, Zimmermann EA, Willie BM, Komarova SV. Mechanically stimulated ATP release from murine bone cells is regulated by a balance of injury and repair. eLife 2018; 7:37812. [PMID: 30324907 PMCID: PMC6205812 DOI: 10.7554/elife.37812] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 09/28/2018] [Indexed: 02/06/2023] Open
Abstract
Bone cells sense and actively adapt to physical perturbations to prevent critical damage. ATP release is among the earliest cellular responses to mechanical stimulation. Mechanical stimulation of a single murine osteoblast led to the release of 70 ± 24 amole ATP, which stimulated calcium responses in neighboring cells. Osteoblasts contained ATP-rich vesicles that were released upon mechanical stimulation. Surprisingly, interventions that promoted vesicular release reduced ATP release, while inhibitors of vesicular release potentiated ATP release. Searching for an alternative ATP release route, we found that mechanical stresses induced reversible cell membrane injury in vitro and in vivo. Ca2+/PLC/PKC-dependent vesicular exocytosis facilitated membrane repair, thereby minimizing cell injury and reducing ATP release. Priming cellular repair machinery prior to mechanical stimulation reduced subsequent membrane injury and ATP release, linking cellular mechanosensitivity to prior mechanical exposure. Thus, our findings position ATP release as an integrated readout of membrane injury and repair. Athletes' skeletons get stronger with training, while bones weaken in people who cannot move or in astronauts experiencing weightlessness. This is because bone cells thrive when exposed to forces. When a bone cell is exposed to a physical force, the first thing that happens is the release of the energy-rich molecule called ATP into the space outside the cell. This molecule then binds to the neighboring cell to unleash a cascade of responses. ATP can exit the cell either through special canals in the cell membrane or released in tiny pod-like structures called vesicles. It is known that strong forces can injure the cell membrane and cause ATP to spill out. However, it is less clear how ATP is released when cells are subjected to regular forces. Mikolajewicz et al. investigated whether ATP exits through injured membranes of cells experiencing regular forces. Bone cells grown in the laboratory were gently poked with a glass needle or placed in a turbulent fluid to simulate forces experienced in the body. Dyes and fluorescent imaging techniques were used to observe the movement of vesicles and calculate the concentration of ATP in these cells. The experiments showed that regular forces in the body do indeed injure the cell membranes and cause ATP to spill out. But importantly, the cells repaired the injuries quickly by releasing vesicles that patch the wound. As soon as the membrane is sealed, ATP stops coming out. From the first injury, cells adapted and quickly strengthened their membrane and repair system to be more resilient against future forces. This process was also seen in the shin bones of mice. These results are important because knowing how bone cells sense, respond and convert physical forces can help us develop treatments for astronauts, the injured and aged.
Collapse
Affiliation(s)
- Nicholas Mikolajewicz
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada.,Shriners Hospital for Children - Canada, Montreal, Quebec, Canada
| | - Elizabeth A Zimmermann
- Shriners Hospital for Children - Canada, Montreal, Quebec, Canada.,Department of Pediatric Surgery, Montreal, Quebec, Canada
| | - Bettina M Willie
- Shriners Hospital for Children - Canada, Montreal, Quebec, Canada.,Department of Pediatric Surgery, Montreal, Quebec, Canada
| | - Svetlana V Komarova
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada.,Shriners Hospital for Children - Canada, Montreal, Quebec, Canada
| |
Collapse
|
28
|
Celli R, Santolini I, Guiducci M, van Luijtelaar G, Parisi P, Striano P, Gradini R, Battaglia G, Ngomba RT, Nicoletti F. The α2δ Subunit and Absence Epilepsy: Beyond Calcium Channels? Curr Neuropharmacol 2018; 15:918-925. [PMID: 28290248 PMCID: PMC5652034 DOI: 10.2174/1570159x15666170309105451] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/16/2017] [Accepted: 03/06/2017] [Indexed: 02/08/2023] Open
Abstract
Background: Spike-wave discharges, underlying absence seizures, are generated within a cortico-thalamo-cortical network that involves the somatosensory cortex, the reticular thalamic nucleus, and the ventrobasal thalamic nuclei. Activation of T-type voltage-sensitive calcium channels (VSCCs) contributes to the pathological oscillatory activity of this network, and some of the first-line drugs used in the treatment of absence epilepsy inhibit T-type calcium channels. The α2δ subunit is a component of high voltage-activated VSCCs (i.e., L-, N-, P/Q-, and R channels) and studies carried out in heterologous expression systems suggest that it may also associate with T channels. The α2δ subunit is also targeted by thrombospondins, which regulate synaptogenesis in the central nervous system. Objective: To discuss the potential role for the thrombospondin/α2δ axis in the pathophysiology of absence epilepsy. Methods: We searched PubMed articles for the terms “absence epilepsy”, “T-type voltage-sensitive calcium channels”, “α2δ subunit”, “ducky mice”, “pregabalin”, “gabapentin”, “thrombospondins”, and included papers focusing this Review's scope. Results: We moved from the evidence that mice lacking the α2δ-2 subunit show absence seizures and α2δ ligands (gabapentin and pregabalin) are detrimental in the treatment of absence epilepsy. This suggests that α2δ may be protective against absence epilepsy via a mechanism that does not involve T channels. We discuss the interaction between thrombospondins and α2δ and its potential relevance in the regulation of excitatory synaptic formation in the cortico-thalamo-cortical network. Conclusion: We speculate on the possibility that the thrombospondin/α2δ axis is critical for the correct functioning of the cortico-thalamo-cortical network, and that abnormalities in this axis may play a role in the pathophysiology of absence epilepsy.
Collapse
Affiliation(s)
- Roberta Celli
- I.R.C.C.S. Neuromed, Neuropharmacology Unit, Pozzilli, (IS), Italy
| | - Ines Santolini
- I.R.C.C.S. Neuromed, Neuropharmacology Unit, Pozzilli, (IS), Italy
| | - Michela Guiducci
- Departments of Neurosciences, Mental Health and Sensory Organs, Experimental Medicine, and Physiology and Pharmacology, University Sapienza, Rome, Italy
| | - Gilles van Luijtelaar
- Donders Centre for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen. Netherlands
| | - Pasquale Parisi
- Departments of Neurosciences, Mental Health and Sensory Organs, Experimental Medicine, and Physiology and Pharmacology, University Sapienza, Rome, Italy
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, "G. Gaslini" Institute, Genova, Italy
| | - Roberto Gradini
- I.R.C.C.S. Neuromed, Neuropharmacology Unit, Pozzilli, (IS), Italy
| | | | - Richard T Ngomba
- University of Lincoln, School of Pharmacy, Lincoln, United Kingdom
| | - Ferdinando Nicoletti
- Department of Physiology and Pharmacology, University Sapienza, Piazzale Aldo Moro, 5, 00185 Rome, Italy
| |
Collapse
|
29
|
Thompson WR, Yen SS, Uzer G, Xie Z, Sen B, Styner M, Burridge K, Rubin J. LARG GEF and ARHGAP18 orchestrate RhoA activity to control mesenchymal stem cell lineage. Bone 2018; 107:172-180. [PMID: 29208526 PMCID: PMC5743610 DOI: 10.1016/j.bone.2017.12.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 11/29/2017] [Accepted: 12/01/2017] [Indexed: 02/02/2023]
Abstract
The quantity and quality of bone depends on osteoblastic differentiation of mesenchymal stem cells (MSCs), where adipogenic commitment depletes the available pool for osteogenesis. Cell architecture influences lineage decisions, where interfering with cytoskeletal structure promotes adipogenesis. Mechanical strain suppresses MSC adipogenesis partially through RhoA driven enhancement of cytoskeletal structure. To understand the basis of force-driven RhoA activation, we considered critical GEFs (activators) and GAPs (inactivators) on bone marrow MSC lineage fate. Knockdown of LARG accelerated adipogenesis and repressed basal RhoA activity. Importantly, mechanical activation of RhoA was almost entirely inhibited following LARG depletion, and the ability of strain to inhibit adipogenesis was impaired. Knockdown of ARHGAP18 increased basal RhoA activity and actin stress fiber formation, but did not enhance mechanical strain activation of RhoA. ARHGAP18 null MSCs exhibited suppressed adipogenesis assessed by Oil-Red-O staining and Western blot of adipogenic markers. Furthermore, ARHGAP18 knockdown enhanced osteogenic commitment, confirmed by alkaline phosphatase staining and qPCR of Sp7, Alpl, and Bglap genes. This suggests that ARHGAP18 conveys tonic inhibition of MSC cytoskeletal assembly, returning RhoA to an "off state" and affecting cell lineage in the static state. In contrast, LARG is recruited during dynamic mechanical strain, and is necessary for mechanical suppression of adipogenesis. In summary, mechanical activation of RhoA in mesenchymal progenitors is dependent on LARG, while ARHGAP18 limits RhoA delineated cytoskeletal structure in static cultures. Thus, on and off GTP exchangers work through RhoA to influence MSC fate and responses to static and dynamic physical factors in the microenvironment.
Collapse
Affiliation(s)
- William R Thompson
- Department of Physical Therapy, School of Health and Rehabilitation Sciences, Indiana University, Indianapolis, IN 46202, United States.
| | - Sherwin S Yen
- Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States.
| | - Gunes Uzer
- Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; Department of Mechanical and Biomedical Engineering, Boise State University, Boise, ID 83725, United States.
| | - Zhihui Xie
- Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States.
| | - Buer Sen
- Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States.
| | - Maya Styner
- Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States.
| | - Keith Burridge
- Department of Cell Biology and Physiology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, United States.
| | - Janet Rubin
- Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States.
| |
Collapse
|
30
|
Cabahug-Zuckerman P, Stout RF, Majeska RJ, Thi MM, Spray DC, Weinbaum S, Schaffler MB. Potential role for a specialized β 3 integrin-based structure on osteocyte processes in bone mechanosensation. J Orthop Res 2018; 36:642-652. [PMID: 29087614 PMCID: PMC5839970 DOI: 10.1002/jor.23792] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 10/21/2017] [Indexed: 02/04/2023]
Abstract
Osteocyte processes are an order of magnitude more sensitive to mechanical loading than their cell bodies. The mechanisms underlying this remarkable mechanosensitivity are not clear, but may be related to the infrequent αV β3 integrin sites where the osteocyte cell processes attach to canalicular walls. These sites develop dramatically elevated strains during load-induced fluid flow in the lacunar-canalicular system and were recently shown to be primary sites for osteocyte-like MLO-Y4 cell mechanotransduction. These αV β3 integrin sites lack typical integrin transduction mechanisms. Rather, stimulation at these sites alters Ca2+ signaling, ATP release and membrane potential. In the current studies, we tested the hypothesis that in authentic osteocytes in situ, key membrane proteins implicated in osteocyte mechanotransduction are preferentially localized at or near to β3 integrin-foci. We analyzed these spatial relationships in mouse bone osteocytes using immunohistochemistry combined with Structured Illumination Super Resolution Microscopy, a method that permits structural resolution at near electron microscopy levels in tissue sections. We discovered that the purinergic channel pannexin1, the ATP-gated purinergic receptor P2 × 7R and the low voltage transiently opened T-type calcium channel CaV3.2-1 all reside in close proximity to β3 integrin attachment foci on osteocyte processes, suggesting a specialized mechanotransduction complex at these sites. We further confirmed this observation on isolated osteocytes in culture using STochasitc Optical Resonance Microscopy. These findings identify a possible structural basis for the unique mechanosensation and transduction capabilities of the osteocyte process. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:642-652, 2018.
Collapse
Affiliation(s)
| | - Randy F. Stout
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine
- Department of Neuroscience, Albert Einstein College of Medicine
| | | | - Mia M. Thi
- Department of Orthopaedic Surgery, Albert Einstein College of Medicine
| | - David C. Spray
- Department of Neuroscience, Albert Einstein College of Medicine
| | - Sheldon Weinbaum
- Department of Biomedical Engineering, The City College of New York
| | | |
Collapse
|
31
|
Yu H, Jiang L, Wan B, Zhang W, Yao L, Che T, Gan C, Su N, He J, Huang J, Zhang K, Zhang Y. The role of aryl hydrocarbon receptor in bone remodeling. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 134:44-49. [PMID: 29277341 DOI: 10.1016/j.pbiomolbio.2017.12.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 12/18/2017] [Accepted: 12/21/2017] [Indexed: 12/12/2022]
Abstract
Bone remodeling is a persistent process for maintaining skeletal system homeostasis, and it depends on the dynamic equilibrium between bone-forming osteoblasts and bone-resorbing osteoclasts. Aryl hydrocarbon receptor (Ahr), a ligand-activated transcription factor, plays a pivotal role in regulating skeletal system. In order to better understand the role of Ahr in bone remodeling, we focused on bone remodeling characteristic, and the effects of Ahr on bone formation and differentiation, which suggest that Ahr is a critical control factor in the process of bone remodeling. Moreover, we discussed the impacts of Ahr on several signaling pathways related to bone remodeling, hoping to provide a theoretical basis to improve bone remodeling.
Collapse
Affiliation(s)
- Haitao Yu
- Department of Clincal Laboratory, The First Hospital of Lanzhou University, West Road No. 1 East Hills, Chengguan District, Lanzhou, 730000, Gansu Province, PR China; The First Clinical College of Lanzhou University, West Road No. 1 East Hills, Chengguan District, Lanzhou, 730000, Gansu Province, PR China.
| | - Lili Jiang
- School of Material Science and Technology, Lanzhou University of Technology, Langongping Road, Lanzhou 730050, Gansu Province, PR China
| | - Bo Wan
- The 3rd and 4th Department of Endocrinology and Metabolism, Lanzhou University Second Hospital, No. 82 Cuiyingmen, Chengguan District, Lanzhou, 730000, Gansu Province, PR China
| | - Wei Zhang
- Cental Laboratory, The First Hospital of Lanzhou University, West Road No. 1 East Hills, Chengguan District, Lanzhou, 730000, Gansu Province, PR China
| | - Liqiong Yao
- Department of Clincal Laboratory, The First Hospital of Lanzhou University, West Road No. 1 East Hills, Chengguan District, Lanzhou, 730000, Gansu Province, PR China
| | - Tuanjie Che
- Gansu Key Laboratory of Functional Genomics and Molecular Diagnosis, East road no. 110 nanhe yantan, Chengguan District, Lanzhou, 730000, Gansu Province, PR China
| | - Chao Gan
- Department of Clincal Laboratory, The First Hospital of Lanzhou University, West Road No. 1 East Hills, Chengguan District, Lanzhou, 730000, Gansu Province, PR China
| | - Na Su
- Department of Clincal Laboratory, The First Hospital of Lanzhou University, West Road No. 1 East Hills, Chengguan District, Lanzhou, 730000, Gansu Province, PR China
| | - Jinchun He
- Department of Clincal Laboratory, The First Hospital of Lanzhou University, West Road No. 1 East Hills, Chengguan District, Lanzhou, 730000, Gansu Province, PR China
| | - Jintian Huang
- The First Clinical College of Lanzhou University, West Road No. 1 East Hills, Chengguan District, Lanzhou, 730000, Gansu Province, PR China
| | - Kaiyun Zhang
- The First Clinical College of Lanzhou University, West Road No. 1 East Hills, Chengguan District, Lanzhou, 730000, Gansu Province, PR China
| | - Yiheng Zhang
- The First Clinical College of Lanzhou University, West Road No. 1 East Hills, Chengguan District, Lanzhou, 730000, Gansu Province, PR China
| |
Collapse
|
32
|
Lyons JS, Joca HC, Law RA, Williams KM, Kerr JP, Shi G, Khairallah RJ, Martin SS, Konstantopoulos K, Ward CW, Stains JP. Microtubules tune mechanotransduction through NOX2 and TRPV4 to decrease sclerostin abundance in osteocytes. Sci Signal 2017; 10:10/506/eaan5748. [PMID: 29162742 DOI: 10.1126/scisignal.aan5748] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The adaptation of the skeleton to its mechanical environment is orchestrated by mechanosensitive osteocytes, largely by regulating the abundance of sclerostin, a secreted inhibitor of bone formation. We defined a microtubule-dependent mechanotransduction pathway that linked fluid shear stress to reactive oxygen species (ROS) and calcium (Ca2+) signals that led to a reduction in sclerostin abundance in cultured osteocytes. We demonstrated that microtubules stabilized by detyrosination, a reversible posttranslational modification of polymerized α-tubulin, determined the stiffness of the cytoskeleton, which set the mechanoresponsive range of cultured osteocytes to fluid shear stress. We showed that fluid shear stress through the microtubule network activated NADPH oxidase 2 (NOX2)-generated ROS that target the Ca2+ channel TRPV4 to elicit Ca2+ influx. Furthermore, tuning the abundance of detyrosinated tubulin affected cytoskeletal stiffness to define the mechanoresponsive range of cultured osteocytes to fluid shear stress. Finally, we demonstrated that NOX2-ROS elicited Ca2+ signals that activated the kinase CaMKII to decrease the abundance of sclerostin protein. Together, these discoveries may identify potentially druggable targets for regulating osteocyte mechanotransduction to affect bone quality.
Collapse
Affiliation(s)
- James S Lyons
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Humberto C Joca
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Robert A Law
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Katrina M Williams
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jaclyn P Kerr
- Department of Orthopaedics, University of Maryland School of Nursing, Baltimore, MD 21201, USA
| | - Guoli Shi
- Department of Orthopaedics, University of Maryland School of Nursing, Baltimore, MD 21201, USA
| | | | - Stuart S Martin
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | | | - Christopher W Ward
- Department of Orthopaedics, University of Maryland School of Nursing, Baltimore, MD 21201, USA.
| | - Joseph P Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| |
Collapse
|
33
|
Cell culture: complications due to mechanical release of ATP and activation of purinoceptors. Cell Tissue Res 2017; 370:1-11. [PMID: 28434079 PMCID: PMC5610203 DOI: 10.1007/s00441-017-2618-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 03/21/2017] [Indexed: 12/11/2022]
Abstract
There is abundant evidence that ATP (adenosine 5′-triphosphate) is released from a variety of cultured cells in response to mechanical stimulation. The release mechanism involved appears to be a combination of vesicular exocytosis and connexin and pannexin hemichannels. Purinergic receptors on cultured cells mediate both short-term purinergic signalling of secretion and long-term (trophic) signalling such as proliferation, migration, differentiation and apoptosis. We aim in this review to bring to the attention of non-purinergic researchers using tissue culture that the release of ATP in response to mechanical stress evoked by the unavoidable movement of the cells acting on functional purinergic receptors on the culture cells is likely to complicate the interpretation of their data.
Collapse
|
34
|
Shen XQ, Geng YM, Liu P, Huang XY, Li SY, Liu CD, Zhou Z, Xu PP. Magnitude-dependent response of osteoblasts regulated by compressive stress. Sci Rep 2017; 7:44925. [PMID: 28317941 PMCID: PMC5357902 DOI: 10.1038/srep44925] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 01/30/2017] [Indexed: 12/17/2022] Open
Abstract
The present study aimed to investigate the role of magnitude in adaptive response of osteoblasts exposed to compressive stress. Murine primary osteoblasts and MC3T3-E1 cells were exposed to compressive stress (0, 1, 2, 3, 4, and 5 g/cm2) in 3D culture. Cell viability was evaluated, and expression levels of Runx2, Alp, Ocn, Rankl, and Opg were examined. ALP activity in osteoblasts and TRAP activity in RAW264.7 cells co-cultured with MC3T3-E1 cells were assayed. Results showed that compressive stress within 5.0 g/cm2 did not influence cell viability. Both osteoblastic and osteoblast-regulated osteoclastic differentiation were enhanced at 2 g/cm2. An increase in stress above 2 g/cm2 did not enhance osteoblastic differentiation further but significantly inhibited osteoblast-regualted osteoclastic differentiation. This study suggested that compressive stress regulates osteoblastic and osteoclastic differentiation through osteoblasts in a magnitude-dependent manner.
Collapse
Affiliation(s)
- Xiao-qing Shen
- Department of Stomatology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
- School of Dentistry, University of Detroit Mercy, Detroit, Michigan, USA
| | - Yuan-ming Geng
- Department of Stomatology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Ping Liu
- Department of Oral and Maxillofacial Surgery, Guangdong Provincial Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Xiang-yu Huang
- Department of Oral and Maxillofacial Surgery, Guangdong Provincial Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Shu-yi Li
- Key laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Chun-dong Liu
- Department of Stomatology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Zheng Zhou
- School of Dentistry, University of Detroit Mercy, Detroit, Michigan, USA
| | - Ping-ping Xu
- Department of Oral and Maxillofacial Surgery, Guangdong Provincial Stomatological Hospital, Southern Medical University, Guangzhou, China
| |
Collapse
|
35
|
The molecular basis of bone mechanotransduction. JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS 2016; 16:221-36. [PMID: 27609037 PMCID: PMC5114345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The skeleton has the ability to perfectly adapt to external forces of the operating environment, by altering its morphology and metabolism in order to meet different needs. This unique adaptive capacity of the skeleton creates an interesting range of biological questions concerning the perception of mechanical or other kinds of signals, the type of receptor, and the molecular pathways involved in this adaptation. Studies of the characteristics of the cellular engineering provide a host of new information that confers to osteocytes the role of the protagonist in the perception and regulation of mechanical effects on the skeleton. The identity of mechanoreceptors is manifold and concerns ion channels, integrins, cell membrane, the cytoskeleton, and other systems. A similar multiplicity characterizes the intracellular signaling. This review describes recent data concerning the outward force reception systems and intracellular transduction pathways of information transfer leading to the continuous adaptation of bone tissue. Increased appreciation of the importance of the mechanical environment in regulating and determining the effectiveness of structural adjustment of the skeleton defines new horizons for the discovery of novel therapeutic approaches to diseases associated with bone loss.
Collapse
|
36
|
Brown GN, Leong PL, Guo XE. T-Type voltage-sensitive calcium channels mediate mechanically-induced intracellular calcium oscillations in osteocytes by regulating endoplasmic reticulum calcium dynamics. Bone 2016; 88:56-63. [PMID: 27108342 PMCID: PMC4899304 DOI: 10.1016/j.bone.2016.04.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 04/18/2016] [Accepted: 04/19/2016] [Indexed: 10/21/2022]
Abstract
One of the earliest responses of bone cells to mechanical stimuli is a rise in intracellular calcium (Ca(2+)), and osteocytes in particular exhibit robust oscillations in Ca(2+) when subjected to loading. Previous studies implicate roles for both the endoplasmic reticulum (ER) and T-Type voltage-sensitive calcium channels (VSCC) in these responses, but their interactions or relative contributions have not been studied. By observing Ca(2+) dynamics in the cytosol (Ca(2+)cyt) and the ER (Ca(2+)ER), the focus of this study was to explore the role of the ER and T-Type channels in Ca(2+) signaling in bone cells. We demonstrate that inhibition of T-Type VSCC in osteocytes significantly reduces the number of Ca(2+)cyt responses and affects Ca(2+)ER depletion dynamics. Simultaneous observation of Ca(2+) exchange among these spaces revealed high synchrony between rises in Ca(2+)cyt and depressions in Ca(2+)ER, and this synchrony was significantly reduced by challenging T-Type VSCC. We further confirmed that this effect was mediated directly through the ER and not through store-operated Ca(2+) entry (SOCE) pathways. Taken together, our data suggests that T-Type VSCC facilitate the recovery of Ca(2+)ER in osteocytes to sustain mechanically-induced Ca(2+) oscillations, uncovering a new mechanism underlying the behavior of osteocytes as mechanosensors.
Collapse
Affiliation(s)
- Genevieve N Brown
- Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
| | - Pui L Leong
- Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
| | - X Edward Guo
- Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA.
| |
Collapse
|
37
|
Understanding Mechanobiology: Physical Therapists as a Force in Mechanotherapy and Musculoskeletal Regenerative Rehabilitation. Phys Ther 2016; 96:560-9. [PMID: 26637643 PMCID: PMC4817213 DOI: 10.2522/ptj.20150224] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 11/22/2015] [Indexed: 12/22/2022]
Abstract
Achieving functional restoration of diseased or injured tissues is the ultimate goal of both regenerative medicine approaches and physical therapy interventions. Proper integration and healing of the surrogate cells, tissues, or organs introduced using regenerative medicine techniques are often dependent on the co-introduction of therapeutic physical stimuli. Thus, regenerative rehabilitation represents a collaborative approach whereby rehabilitation specialists, basic scientists, physicians, and surgeons work closely to enhance tissue restoration by creating tailored rehabilitation treatments. One of the primary treatment regimens that physical therapists use to promote tissue healing is the introduction of mechanical forces, or mechanotherapies. These mechanotherapies in regenerative rehabilitation activate specific biological responses in musculoskeletal tissues to enhance the integration, healing, and restorative capacity of implanted cells, tissues, or synthetic scaffolds. To become future leaders in the field of regenerative rehabilitation, physical therapists must understand the principles of mechanobiology and how mechanotherapies augment tissue responses. This perspective article provides an overview of mechanotherapy and discusses how mechanical signals are transmitted at the tissue, cellular, and molecular levels. The synergistic effects of physical interventions and pharmacological agents also are discussed. The goals are to highlight the critical importance of mechanical signals on biological tissue healing and to emphasize the need for collaboration within the field of regenerative rehabilitation. As this field continues to emerge, physical therapists are poised to provide a critical contribution by integrating mechanotherapies with regenerative medicine to restore musculoskeletal function.
Collapse
|
38
|
Uzer G, Fuchs RK, Rubin J, Thompson WR. Concise Review: Plasma and Nuclear Membranes Convey Mechanical Information to Regulate Mesenchymal Stem Cell Lineage. Stem Cells 2016; 34:1455-63. [PMID: 26891206 DOI: 10.1002/stem.2342] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 12/14/2015] [Accepted: 12/29/2015] [Indexed: 12/21/2022]
Abstract
Numerous factors including chemical, hormonal, spatial, and physical cues determine stem cell fate. While the regulation of stem cell differentiation by soluble factors is well-characterized, the role of mechanical force in the determination of lineage fate is just beginning to be understood. Investigation of the role of force on cell function has largely focused on "outside-in" signaling, initiated at the plasma membrane. When interfaced with the extracellular matrix, the cell uses integral membrane proteins, such as those found in focal adhesion complexes to translate force into biochemical signals. Akin to these outside-in connections, the internal cytoskeleton is physically linked to the nucleus, via proteins that span the nuclear membrane. Although structurally and biochemically distinct, these two forms of mechanical coupling influence stem cell lineage fate and, when disrupted, often lead to disease. Here we provide an overview of how mechanical coupling occurs at the plasma and nuclear membranes. We also discuss the role of force on stem cell differentiation, with focus on the biochemical signals generated at the cell membrane and the nucleus, and how those signals influence various diseases. While the interaction of stem cells with their physical environment and how they respond to force is complex, an understanding of the mechanical regulation of these cells is critical in the design of novel therapeutics to combat diseases associated with aging, cancer, and osteoporosis. Stem Cells 2016;34:1455-1463.
Collapse
Affiliation(s)
- Gunes Uzer
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Robyn K Fuchs
- School of Health and Rehabilitation Sciences, Department of Physical Therapy, Indiana University, Indianapolis, Indiana, USA
| | - Janet Rubin
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - William R Thompson
- School of Health and Rehabilitation Sciences, Department of Physical Therapy, Indiana University, Indianapolis, Indiana, USA
| |
Collapse
|
39
|
Noronha-Matos JB, Correia-de-Sá P. Mesenchymal Stem Cells Ageing: Targeting the "Purinome" to Promote Osteogenic Differentiation and Bone Repair. J Cell Physiol 2016; 231:1852-61. [PMID: 26754327 DOI: 10.1002/jcp.25303] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 01/07/2016] [Indexed: 12/11/2022]
Abstract
Mesenchymal stem cells (MSCs) are multipotent cells that can differentiate into bone forming cells. Such ability is compromised in elderly individuals resulting in bone disorders such as osteoporosis, also limiting their clinical usage for cell transplantation and bone tissue engineering strategies. In bone marrow niches, adenine and uracil nucleotides are important local regulators of osteogenic differentiation of MSCs. Nucleotides can be released to the extracellular milieu under both physiological and pathological conditions via (1) membrane cell damage, (2) vesicle exocytosis, (3) ATP-binding cassette transporters, and/or (4) facilitated diffusion through maxi-anion channels, hemichannels or ligand-gated receptor pores. Nucleotides and their derivatives act via adenosine P1 (A1 , A2A , A2B , and A3 ) and nucleotide-sensitive P2 purinoceptors comprising ionotropic P2X and G-protein-coupled P2Y receptors. Purinoceptors activation is terminated by membrane-bound ecto-nucleotidases and other ecto-phosphatases, which rapidly hydrolyse extracellular nucleotides to their respective nucleoside 5'-di- and mono-phosphates, nucleosides and free phosphates, or pyrophosphates. Current knowledge suggests that different players of the "purinome" cascade, namely nucleotide release sites, ecto-nucleotidases and purinoceptors, orchestrate to fine-tuning regulate the activity of MSCs in the bone microenvironment. Increasing studies, using osteoprogenitor cell lines, animal models and, more recently, non-modified MSCs from postmenopausal women, raised the possibility to target chief components of the purinergic signaling pathway to regenerate the ability of aged MSCs to differentiate into functional osteoblasts. This review summarizes the main findings of those studies, prompting for novel therapeutic strategies to control ageing disorders where bone destruction exceeds bone formation, like osteoporosis, rheumatoid arthritis, and fracture mal-union. J. Cell. Physiol. 231: 1852-1861, 2016. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- J B Noronha-Matos
- Laboratório de Farmacologia e Neurobiologia-Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar-Universidade do Porto (ICBAS-UP), Portugal
| | - P Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia-Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar-Universidade do Porto (ICBAS-UP), Portugal
| |
Collapse
|
40
|
Lai X, Price C, Modla S, Thompson WR, Caplan J, Kirn-Safran CB, Wang L. The dependences of osteocyte network on bone compartment, age, and disease. Bone Res 2015; 3. [PMID: 26213632 PMCID: PMC4511381 DOI: 10.1038/boneres.2015.9] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Osteocytes, the most abundant bone cells, form an interconnected network in the lacunar-canalicular pore system (LCS) buried within the mineralized matrix, which allows osteocytes to obtain nutrients from the blood supply, sense external mechanical signals, and communicate among themselves and with other cells on bone surfaces. In this study, we examined key features of the LCS network including the topological parameter and the detailed structure of individual connections and their variations in cortical and cancellous compartments, at different ages, and in two disease conditions with altered mechanosensing (perlecan deficiency and diabetes). LCS network showed both topological stability, in terms of conservation of connectivity among osteocyte lacunae (similar to the "nodes" in a computer network), and considerable variability the pericellular annular fluid gap surrounding lacunae and canaliculi (similar to the "bandwidth" of individual links in a computer network). Age, in the range of our study (15-32 weeks), affected only the pericellular fluid annulus in cortical bone but not in cancellous bone. Diabetes impacted the spacing of the lacunae, while the perlecan deficiency had a profound influence on the pericellular fluid annulus. The LCS network features play important roles in osteocyte signaling and regulation of bone growth and adaptation.
Collapse
Affiliation(s)
- Xiaohan Lai
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - Christopher Price
- Biomedical Engineering Program, University of Delaware, Newark, DE, USA
| | - Shannon Modla
- DBI Bioimaging Center, University of Delaware, Newark, DE, USA
| | - William R Thompson
- Department of Physical Therapy, Indiana University, Indianapolis, IN, USA
| | - Jeffrey Caplan
- DBI Bioimaging Center, University of Delaware, Newark, DE, USA
| | | | - Liyun Wang
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| |
Collapse
|
41
|
Sun Z, Cao X, Hu Z, Zhang L, Wang H, Zhou H, Li D, Zhang S, Xie M. MiR-103 inhibits osteoblast proliferation mainly through suppressing Cav1.2 expression in simulated microgravity. Bone 2015; 76:121-8. [PMID: 25868801 DOI: 10.1016/j.bone.2015.04.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 03/17/2015] [Accepted: 04/02/2015] [Indexed: 01/22/2023]
Abstract
Emerging evidence indicates that microRNAs (miRNAs) play important roles in modulating osteoblast function and bone formation. However, the influence of miRNA on osteoblast proliferation and the possible mechanisms underlying remain to be defined. In this study, we aimed to investigate whether miR-103 regulates osteoblast proliferation under simulated microgravity condition through regulating Cav1.2, the primary subunit of L-type voltage sensitive calcium channels (LTCCs). We first investigated the effect of simulated microgravity on osteoblast proliferation and the outcomes clearly demonstrated that the mechanical unloading inhibits MC3T3-E1 osteoblast-like cell proliferation. Using quantitative Real-Time PCR (qRT-PCR), we provided data showing that miR-103 was up-regulated in response to simulated microgravity. In addition, we observed that up-regulation of miR-103 inhibited and down-regulation of miR-103 promoted osteoblast proliferation under simulated microgravity condition. Furthermore, knocking-down or over-expressing miR-103, respectively, up- or down-regulated the level of Cav1.2 expression and LTCC currents, suggesting that miR-103 acts as an endogenous attenuator of Cav1.2 in osteoblasts under simulated microgravity condition. More importantly, we showed that the effect of miR-103 on osteoblast proliferation was diminished in simulated microgravity, when co-transfecting miR-103 mimic or inhibitor with Cav1.2 siRNA. Taken together, our data suggest that miR-103 inhibits osteoblast proliferation mainly through suppression of Cav1.2 expression under simulated microgravity condition. This work may provide a novel mechanism of microgravity-induced detrimental effects on osteoblast proliferation, identifying miR-103 as a novel possible therapeutic target in bone remodeling disorders in this mechanical unloading.
Collapse
Affiliation(s)
- Zhongyang Sun
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032 Xi'an, Shaanxi, China
| | - Xinsheng Cao
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032 Xi'an, Shaanxi, China
| | - Zebing Hu
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032 Xi'an, Shaanxi, China
| | - Lianchang Zhang
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032 Xi'an, Shaanxi, China
| | - Han Wang
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032 Xi'an, Shaanxi, China
| | - Hua Zhou
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032 Xi'an, Shaanxi, China
| | - Dongtao Li
- Center of Cardiology, Navy General Hospital, 100048 Beijing, China
| | - Shu Zhang
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032 Xi'an, Shaanxi, China.
| | - Manjiang Xie
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032 Xi'an, Shaanxi, China.
| |
Collapse
|
42
|
Osteocyte specific responses to soluble and mechanical stimuli in a stem cell derived culture model. Sci Rep 2015; 5:11049. [PMID: 26056071 PMCID: PMC4460727 DOI: 10.1038/srep11049] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 05/07/2015] [Indexed: 11/08/2022] Open
Abstract
Studying osteocyte behavior in culture has proven difficult because these embedded cells require spatially coordinated interactions with the matrix and surrounding cells to achieve the osteocyte phenotype. Using an easily attainable source of bone marrow mesenchymal stem cells, we generated cells with the osteocyte phenotype within two weeks. These "stem cell derived-osteocytes" (SCD-O) displayed stellate morphology and lacunocanalicular ultrastructure. Osteocytic genes Sost, Dmp1, E11, and Fgf23 were maximally expressed at 15 days and responded to PTH and 1,25(OH)2D3. Production of sclerostin mRNA and protein, within 15 days of culture makes the SCD-O model ideal for elucidating regulatory mechanisms. We found sclerostin to be regulated by mechanical factors, where low intensity vibration significantly reduced Sost expression. Additionally, this model recapitulates sclerostin production in response to osteoactive hormones, as PTH or LIV repressed secretion of sclerostin, significantly impacting Wnt-mediated Axin2 expression, via β-catenin signaling. In summary, SCD-O cells produce abundant matrix, rapidly attain the osteocyte phenotype, and secrete functional factors including sclerostin under non-immortalized conditions. This culture model enables ex vivo observations of osteocyte behavior while preserving an organ-like environment. Furthermore, as marrow-derived mesenchymal stem cells can be obtained from transgenic animals; our model enables study of genetic control of osteocyte behaviors.
Collapse
|
43
|
Abstract
Accumulating evidence now suggests that purinergic signalling exerts significant regulatory effects in the musculoskeletal system. In particular, it has emerged that extracellular nucleotides are key regulators of bone cell differentiation, survival and function. This review discusses our current understanding of the direct effects of purinergic signalling in bone, cartilage and muscle.
Collapse
Affiliation(s)
- Isabel R Orriss
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London NW1 0TU, United Kingdom.
| |
Collapse
|
44
|
Sun Z, Cao X, Zhang Z, Hu Z, Zhang L, Wang H, Zhou H, Li D, Zhang S, Xie M. Simulated microgravity inhibits L-type calcium channel currents partially by the up-regulation of miR-103 in MC3T3-E1 osteoblasts. Sci Rep 2015; 5:8077. [PMID: 25627864 PMCID: PMC4308706 DOI: 10.1038/srep08077] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/05/2015] [Indexed: 11/25/2022] Open
Abstract
L-type voltage-sensitive calcium channels (LTCCs), particularly Cav1.2 LTCCs, play fundamental roles in cellular responses to mechanical stimuli in osteoblasts. Numerous studies have shown that mechanical loading promotes bone formation, whereas the removal of this stimulus under microgravity conditions results in a reduction in bone mass. However, whether microgravity exerts an influence on LTCCs in osteoblasts and whether this influence is a possible mechanism underlying the observed bone loss remain unclear. In the present study, we demonstrated that simulated microgravity substantially inhibited LTCC currents and suppressed Cav1.2 at the protein level in MC3T3-E1 osteoblast-like cells. In addition, reduced Cav1.2 protein levels decreased LTCC currents in MC3T3-E1 cells. Moreover, simulated microgravity increased miR-103 expression. Cav1.2 expression and LTCC current densities both significantly increased in cells that were transfected with a miR-103 inhibitor under mechanical unloading conditions. These results suggest that simulated microgravity substantially inhibits LTCC currents in osteoblasts by suppressing Cav1.2 expression. Furthermore, the down-regulation of Cav1.2 expression and the inhibition of LTCCs caused by mechanical unloading in osteoblasts are partially due to miR-103 up-regulation. Our study provides a novel mechanism for microgravity-induced detrimental effects on osteoblasts, offering a new avenue to further investigate the bone loss induced by microgravity.
Collapse
Affiliation(s)
- Zhongyang Sun
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032, Xi'an, Shaanxi, China
| | - Xinsheng Cao
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032, Xi'an, Shaanxi, China
| | - Zhuo Zhang
- Department of Neurology, Tangdu Hospital, The Fourth Military Medical University, 710032, Xi'an, Shaanxi, China
| | - Zebing Hu
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032, Xi'an, Shaanxi, China
| | - Lianchang Zhang
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032, Xi'an, Shaanxi, China
| | - Han Wang
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032, Xi'an, Shaanxi, China
| | - Hua Zhou
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032, Xi'an, Shaanxi, China
| | - Dongtao Li
- Center of Cardiology, Navy General Hospital, 100048, Beijing, China
| | - Shu Zhang
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032, Xi'an, Shaanxi, China
| | - Manjiang Xie
- The Key Laboratory of Aerospace Medicine, Ministry of Education, The Fourth Military Medical University, 710032, Xi'an, Shaanxi, China
| |
Collapse
|
45
|
Targeting P2 receptors--current progress in treating musculoskeletal diseases. Curr Opin Pharmacol 2014; 16:122-6. [PMID: 24880708 DOI: 10.1016/j.coph.2014.05.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 05/05/2014] [Accepted: 05/05/2014] [Indexed: 12/12/2022]
Abstract
It is widely recognized that purinergic signalling, extracellular nucleotides acting at purinergic receptors, is the most primitive and ubiquitous signalling system participating in numerous biological processes in almost all tissue types. The P2 receptors, including P2X and P2Y purinoceptor subtypes, have been proposed to play important roles in the musculoskeletal systems since the early 1990s. During the past five years, significant progress in this field has been made; this review will summarize these most recent developments and highlight the pharmaceutical potential from these findings.
Collapse
|
46
|
Cav3.2 T-type calcium channel is required for the NFAT-dependent Sox9 expression in tracheal cartilage. Proc Natl Acad Sci U S A 2014; 111:E1990-8. [PMID: 24778262 DOI: 10.1073/pnas.1323112111] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Intracellular Ca(2+) transient is crucial in initiating the differentiation of mesenchymal cells into chondrocytes, but whether voltage-gated Ca(2+) channels are involved remains uncertain. Here, we show that the T-type voltage-gated Ca(2+) channel Cav3.2 is essential for tracheal chondrogenesis. Mice lacking this channel (Cav3.2(-/-)) show congenital tracheal stenosis because of incomplete formation of cartilaginous tracheal support. Conversely, Cav3.2 overexpression in ATDC5 cells enhances chondrogenesis, which could be blunted by both blocking T-type Ca(2+) channels and inhibiting calcineurin and suggests that Cav3.2 is responsible for Ca(2+) influx during chondrogenesis. Finally, the expression of sex determination region of Y chromosome (SRY)-related high-mobility group-Box gene 9 (Sox9), one of the earliest markers of committed chondrogenic cells, is reduced in Cav3.2(-/-) tracheas. Mechanistically, Ca(2+) influx via Cav3.2 activates the calcineurin/nuclear factor of the activated T-cell (NFAT) signaling pathway, and a previously unidentified NFAT binding site is identified within the mouse Sox9 promoter using a luciferase reporter assay and gel shift and ChIP studies. Our findings define a previously unidentified mechanism that Ca(2+) influx via the Cav3.2 T-type Ca(2+) channel regulates Sox9 expression through the calcineurin/NFAT signaling pathway during tracheal chondrogenesis.
Collapse
|
47
|
Li P, Liu C, Hu M, Long M, Zhang D, Huo B. Fluid flow-induced calcium response in osteoclasts: signaling pathways. Ann Biomed Eng 2014; 42:1250-60. [PMID: 24710796 DOI: 10.1007/s10439-014-0984-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 01/25/2014] [Indexed: 01/07/2023]
Abstract
Intracellular calcium oscillation and its downstream signaling in osteoclasts is believed to play critical roles in regulating bone resorption. Our previous study demonstrated that fluid shear stress (FSS) induced more calcium responsive peaks in the late differentiated osteoclasts than the early ones. In this paper, the signaling pathways of FSS-induced calcium response for the osteoclasts in different differentiation stages were studied. RAW264.7 macrophage cells were induced to differentiate into osteoclasts with the conditioned medium from MC3T3-E1 osteoblasts. Furthermore pharmacological agents were added to block the specific signaling pathways. Finally the cells were exposed to FSS at different levels (1 or 10 dyne/cm(2)) after being induced for 4 or 8 days. The results showed that the mechanosensitive, cation-selective channels, phospholipase C (PLC) and endoplasmic reticulum constituted the major signaling pathway for mechanical stimulation-induced calcium response in osteoclasts. Extracellular calcium or ATP involved with calcium oscillation in a FSS magnitude-dependent manner. This pathway study may help to give insight into the molecular mechanism of mechanical stimulation-regulated bone remodeling.
Collapse
Affiliation(s)
- Ping Li
- Department of Mechanics, School of Aerospace Engineering, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Beijing, 100081, People's Republic of China
| | | | | | | | | | | |
Collapse
|
48
|
Wang B, Lai X, Price C, Thompson WR, Li W, Quabili TR, Tseng WJ, Liu XS, Zhang H, Pan J, Kirn-Safran CB, Farach-Carson MC, Wang L. Perlecan-containing pericellular matrix regulates solute transport and mechanosensing within the osteocyte lacunar-canalicular system. J Bone Miner Res 2014; 29:878-91. [PMID: 24115222 PMCID: PMC3962519 DOI: 10.1002/jbmr.2105] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 09/13/2013] [Accepted: 09/19/2013] [Indexed: 11/09/2022]
Abstract
The pericellular matrix (PCM), a thin coating surrounding nearly all mammalian cells, plays a critical role in many cell-surface phenomena. In osteocytes, the PCM is believed to control both "outside-in" (mechanosensing) and "inside-out" (signaling molecule transport) processes. However, the osteocytic PCM is challenging to study in situ because it is thin (∼100 nm) and enclosed in mineralized matrix. To this end, we recently developed a novel tracer velocimetry approach that combined fluorescence recovery after photobleaching (FRAP) imaging with hydrodynamic modeling to quantify the osteocytic PCM in young murine bone. In this study, we applied the technique to older mice expressing or deficient for perlecan/HSPG2, a large heparan-sulfate proteoglycan normally secreted in osteocytic PCM. The objectives were (1) to characterize transport within an altered PCM; (2) to test the sensitivity of our approach in detecting the PCM alterations; and (3) to dissect the roles of the PCM in osteocyte mechanosensing. We found that: (1) solute transport increases in the perlecan-deficient (hypomorphic [Hypo]) mice compared with control mice; (2) PCM fiber density decreases with aging and perlecan deficiency; (3) osteocytes in the Hypo bones are predicted to experience higher shear stress (+34%), but decreased fluid drag force (-35%) under 3-N peak tibial loading; and (4) when subjected to tibial loading in a preliminary in vivo experiment, the Hypo mice did not respond to the anabolic stimuli as the CTL mice did. These findings support the hypothesis that the PCM fibers act as osteocyte's sensing antennae, regulating load-induced cellular stimulations and thus bone's sensitivity and in vivo bone adaptation. If this hypothesis is further confirmed, osteocytic PCM could be new targets to develop osteoporosis treatments by modulating bone's intrinsic sensitivity to mechanical loading and be used to design patient-specific exercise regimens to promote bone formation.
Collapse
Affiliation(s)
- Bin Wang
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA; Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, PR China
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Schaffler MB, Cheung WY, Majeska R, Kennedy O. Osteocytes: master orchestrators of bone. Calcif Tissue Int 2014; 94:5-24. [PMID: 24042263 PMCID: PMC3947191 DOI: 10.1007/s00223-013-9790-y] [Citation(s) in RCA: 305] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 08/22/2013] [Indexed: 12/12/2022]
Abstract
Osteocytes comprise the overwhelming majority of cells in bone and are its only true "permanent" resident cell population. In recent years, conceptual and technological advances on many fronts have helped to clarify the role osteocytes play in skeletal metabolism and the mechanisms they use to perform them. The osteocyte is now recognized as a major orchestrator of skeletal activity, capable of sensing and integrating mechanical and chemical signals from their environment to regulate both bone formation and resorption. Recent studies have established that the mechanisms osteocytes use to sense stimuli and regulate effector cells (e.g., osteoblasts and osteoclasts) are directly coupled to the environment they inhabit-entombed within the mineralized matrix of bone and connected to each other in multicellular networks. Communication within these networks is both direct (via cell-cell contacts at gap junctions) and indirect (via paracrine signaling by secreted signals). Moreover, the movement of paracrine signals is dependent on the movement of both solutes and fluid through the space immediately surrounding the osteocytes (i.e., the lacunar-canalicular system). Finally, recent studies have also shown that the regulatory capabilities of osteocytes extend beyond bone to include a role in the endocrine control of systemic phosphate metabolism. This review will discuss how a highly productive combination of experimental and theoretical approaches has managed to unearth these unique features of osteocytes and bring to light novel insights into the regulatory mechanisms operating in bone.
Collapse
Affiliation(s)
- Mitchell B. Schaffler
- University: City College of New York, Department: Biomedical Engineering, Phone: 212-650-5070, Fax: 212-650-6727
| | - Wing-Yee Cheung
- University: City College of New York, Department: Biomedical Engineering
| | - Robert Majeska
- University: City College of New York, Department: Biomedical Engineering
| | - Oran Kennedy
- University: New York University, Department: Orthopaedic Surgery
| |
Collapse
|
50
|
Riquelme MA, Jiang JX. Elevated Intracellular Ca(2+) Signals by Oxidative Stress Activate Connexin 43 Hemichannels in Osteocytes. Bone Res 2013; 1:355-61. [PMID: 26273513 DOI: 10.4248/br201304006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 10/27/2013] [Indexed: 12/24/2022] Open
Abstract
Elevated oxidative stress (OS) during aging leads to bone loss. OS increases intracellular Ca(2+) ([Ca(2+)]i), resulting in cellular damage and death. We show earlier that Cx43 hemichannels open in response to OS, which serves as a protective mechanism for osteocytes. However, the underlying mechanism is unknown. Here, we found that treatment with H2O2 increased [Ca(2+)]i in osteocytes with [Ca(2+)]i being primarily derived from an extracellular Ca(2+) source. Hemichannel opening induced by OS was inhibited by the depletion of [Ca(2+)]i with BAPTA-AM, a Ca(2+) chelator, suggesting that [Ca(2+)]i influenced the activity of Cx43 hemichannels. Conversely, blockade of hemichannels had no effect on [Ca(2+)]i. A biotinylation assay showed that cell surface-expressed Cx43 was increased by OS, which could be inhibited by BAPTA-AM, suggesting that [Ca(2+)]i is necessary for Cx43 migration to the cell surface in response to OS. Together, these data suggest that increased hemichannel activity induced by OS was likely to be caused by elevated [Ca(2+)]i through increased Cx43 on the cell surface.
Collapse
Affiliation(s)
- Manuel A Riquelme
- Department of Biochemistry, the University of Texas Health Science Center San Antonio , San Antonio, Texas 78229-3900, USA
| | - Jean X Jiang
- Department of Biochemistry, the University of Texas Health Science Center San Antonio , San Antonio, Texas 78229-3900, USA
| |
Collapse
|