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Moore ER. Primary Cilia: The New Face of Craniofacial Research. Biomolecules 2022; 12:biom12121724. [PMID: 36551151 PMCID: PMC9776107 DOI: 10.3390/biom12121724] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/17/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022] Open
Abstract
The primary cilium is a solitary, sensory organelle that extends from the surface of nearly every vertebrate cell, including craniofacial cells. This organelle converts chemical and physical external stimuli into intracellular signaling cascades and mediates several well-known signaling pathways simultaneously. Thus, the primary cilium is considered a cellular signaling nexus and amplifier. Primary cilia dysfunction directly results in a collection of diseases and syndromes that typically affect multiple organ systems, including the face and teeth. Despite this direct connection, primary cilia are largely unexplored in craniofacial research. In this review, I briefly summarize craniofacial abnormalities tied to the primary cilium and examine the existing information on primary cilia in craniofacial development and repair. I close with a discussion on preliminary studies that motivate future areas of exploration that are further supported by studies performed in long bone and kidney cells.
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Affiliation(s)
- Emily R Moore
- Harvard School of Dental Medicine, Department of Developmental Biology, 188 Longwood Avenue, Boston, MA 02115, USA
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2
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Yuan B, Zhang Y, Zhao R, Lin H, Yang X, Zhu X, Zhang K, Mikos AG, Zhang X. A unique biomimetic modification endows polyetherketoneketone scaffold with osteoinductivity by activating cAMP/PKA signaling pathway. SCIENCE ADVANCES 2022; 8:eabq7116. [PMID: 36197987 PMCID: PMC9534509 DOI: 10.1126/sciadv.abq7116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 08/17/2022] [Indexed: 06/16/2023]
Abstract
Osteoinductivity of a biomaterial scaffold can notably enhance the bone healing performance. In this study, we developed a biomimetic and hierarchically porous polyetherketoneketone (PEKK) scaffold with unique osteoinductivity using a combined surface treatment strategy of a sulfonated process and a nano bone-like apatite deposition. In a beagle intramuscular model, the scaffold induced bone formation ectopically after 12-week implantation. The better bone healing ability of the scaffold than the original PEKK was also confirmed in orthotopic sites. After culturing with bone marrow-derived mesenchymal stem cells (BMSCs), the scaffold induced osteogenic differentiation of BMSCs, and the new bone formation could be mainly depending on cell signaling through adenylate cyclase 9, which activates the cyclic adenosine monophosphate/protein kinase A signaling cascade pathways. The current work reports a new osteoinductive synthetic polymeric scaffold with its detailed molecular mechanism of action for bone repair and regeneration.
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Affiliation(s)
- Bo Yuan
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China
- School of Biomedical Engineering, Sichuan University, Chengdu 610064, P. R. China
| | - Yuxiang Zhang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China
- School of Biomedical Engineering, Sichuan University, Chengdu 610064, P. R. China
| | - Rui Zhao
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China
- School of Biomedical Engineering, Sichuan University, Chengdu 610064, P. R. China
| | - Hai Lin
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China
- School of Biomedical Engineering, Sichuan University, Chengdu 610064, P. R. China
| | - Xiao Yang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China
- School of Biomedical Engineering, Sichuan University, Chengdu 610064, P. R. China
| | - Xiangdong Zhu
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China
- School of Biomedical Engineering, Sichuan University, Chengdu 610064, P. R. China
| | - Kai Zhang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China
- School of Biomedical Engineering, Sichuan University, Chengdu 610064, P. R. China
- Institute of Regulatory Science for Medical Device, Sichuan University, Chengdu 610064, P. R. China
| | - Antonios G. Mikos
- Departments of Bioengineering and Chemical and Biomolecular Engineering, Rice University, Houston, TX 77251, USA
| | - Xingdong Zhang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China
- School of Biomedical Engineering, Sichuan University, Chengdu 610064, P. R. China
- Institute of Regulatory Science for Medical Device, Sichuan University, Chengdu 610064, P. R. China
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3
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Jeon HH, Kang J, Li J(M, Kim D, Yuan G, Almer N, Liu M, Yang S. The Effect of IFT80 Deficiency in Osteocytes on Orthodontic Loading-Induced and Physiologic Bone Remodeling: In Vivo Study. Life (Basel) 2022; 12:1147. [PMID: 36013326 PMCID: PMC9410307 DOI: 10.3390/life12081147] [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: 06/22/2022] [Revised: 07/24/2022] [Accepted: 07/26/2022] [Indexed: 11/17/2022] Open
Abstract
Osteocytes are the main mechanosensory cells during orthodontic and physiologic bone remodeling. However, the question of how osteocytes transmit mechanical stimuli to biological responses remains largely unanswered. Intraflagellar transport (IFT) proteins are important for the formation and function of cilia, which are proposed to be mechanical sensors in osteocytes. In particular, IFT80 is highly expressed in mouse skulls and essential for ciliogenesis. This study aims to investigate the short- and long-term effects of IFT80 deletion in osteocytes on orthodontic bone remodeling and physiological bone remodeling in response to masticatory force. We examined 10-week-old experimental DMP1 CRE+.IFT80f/f and littermate control DMP1 CRE-.IFT80f/f mice. After 5 and 12 days of orthodontic force loading, the orthodontic tooth movement distance and bone parameters were evaluated using microCT. Osteoclast formation was assessed using TRAP-stained paraffin sections. The expression of sclerostin and RANKL was examined using immunofluorescence stain. We found that the deletion of IFT80 in osteocytes did not significantly impact either orthodontic or physiologic bone remodeling, as demonstrated by similar OTM distances, osteoclast numbers, bone volume fractions (bone volume/total volume), bone mineral densities, and the expressions of sclerostin and RANKL. Our findings suggest that there are other possible mechanosensory systems in osteocytes and anatomic limitations to cilia deflection in osteocytes in vivo.
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Affiliation(s)
- Hyeran Helen Jeon
- Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (J.K.); (J.L.); (D.K.); (N.A.)
| | - Jessica Kang
- Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (J.K.); (J.L.); (D.K.); (N.A.)
| | - Jiahui (Madelaine) Li
- Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (J.K.); (J.L.); (D.K.); (N.A.)
| | - Douglas Kim
- Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (J.K.); (J.L.); (D.K.); (N.A.)
| | - Gongsheng Yuan
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Nicolette Almer
- Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (J.K.); (J.L.); (D.K.); (N.A.)
| | - Min Liu
- Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Shuying Yang
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
- The Penn Center for Musculoskeletal Disorders, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Innovation & Precision Dentistry, School of Dental Medicine, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
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4
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Spasic M, Duffy MP, Jacobs CR. Fenoldopam Sensitizes Primary Cilia-Mediated Mechanosensing to Promote Osteogenic Intercellular Signaling and Whole Bone Adaptation. J Bone Miner Res 2022; 37:972-982. [PMID: 35230705 PMCID: PMC9098671 DOI: 10.1002/jbmr.4536] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 02/01/2022] [Accepted: 02/12/2022] [Indexed: 11/05/2022]
Abstract
Bone cells actively respond to mechanical stimuli to direct bone formation, yet there is no current treatment strategy for conditions of low bone mass and osteoporosis designed to target the inherent mechanosensitivity of bone. Our group has previously identified the primary cilium as a critical mechanosensor within bone, and that pharmacologically targeting the primary cilium with fenoldopam can enhance osteocyte mechanosensitivity. Here, we demonstrate that potentiating osteocyte mechanosensing with fenoldopam in vitro promotes pro-osteogenic paracrine signaling to osteoblasts. Conversely, impairing primary cilia formation and the function of key ciliary mechanotransduction proteins attenuates this intercellular signaling cascade. We then utilize an in vivo model of load-induced bone formation to demonstrate that fenoldopam treatment sensitizes bones of both healthy and osteoporotic mice to mechanical stimulation. Furthermore, we show minimal adverse effects of this treatment and demonstrate that prolonged treatment biases trabecular bone adaptation. This work is the first to examine the efficacy of targeting primary cilia-mediated mechanosensing to enhance bone formation in osteoporotic animals. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Milos Spasic
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Michael P Duffy
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
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5
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Ostrom KF, LaVigne JE, Brust TF, Seifert R, Dessauer CW, Watts VJ, Ostrom RS. Physiological roles of mammalian transmembrane adenylyl cyclase isoforms. Physiol Rev 2022; 102:815-857. [PMID: 34698552 PMCID: PMC8759965 DOI: 10.1152/physrev.00013.2021] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 09/20/2021] [Accepted: 10/19/2021] [Indexed: 12/12/2022] Open
Abstract
Adenylyl cyclases (ACs) catalyze the conversion of ATP to the ubiquitous second messenger cAMP. Mammals possess nine isoforms of transmembrane ACs, dubbed AC1-9, that serve as major effector enzymes of G protein-coupled receptors (GPCRs). The transmembrane ACs display varying expression patterns across tissues, giving the potential for them to have a wide array of physiological roles. Cells express multiple AC isoforms, implying that ACs have redundant functions. Furthermore, all transmembrane ACs are activated by Gαs, so it was long assumed that all ACs are activated by Gαs-coupled GPCRs. AC isoforms partition to different microdomains of the plasma membrane and form prearranged signaling complexes with specific GPCRs that contribute to cAMP signaling compartments. This compartmentation allows for a diversity of cellular and physiological responses by enabling unique signaling events to be triggered by different pools of cAMP. Isoform-specific pharmacological activators or inhibitors are lacking for most ACs, making knockdown and overexpression the primary tools for examining the physiological roles of a given isoform. Much progress has been made in understanding the physiological effects mediated through individual transmembrane ACs. GPCR-AC-cAMP signaling pathways play significant roles in regulating functions of every cell and tissue, so understanding each AC isoform's role holds potential for uncovering new approaches for treating a vast array of pathophysiological conditions.
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Affiliation(s)
| | - Justin E LaVigne
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
| | - Tarsis F Brust
- Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida
| | - Roland Seifert
- Institute of Pharmacology, Hannover Medical School, Hannover, Germany
| | - Carmen W Dessauer
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas
| | - Val J Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
- Purdue Institute for Drug Discovery, Purdue University, West Lafayette, Indiana
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana
| | - Rennolds S Ostrom
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California
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6
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Abstract
PURPOSE OF REVIEW Postmenopausal osteoporosis reduces circulating estrogen levels, which leads to osteoclast resorption, bone loss, and fracture. This review addresses emerging evidence that osteoporosis is not simply a disease of bone loss but that mechanosensitive osteocytes that regulate both osteoclasts and osteoblasts are also impacted by estrogen deficiency. RECENT FINDINGS At the onset of estrogen deficiency, the osteocyte mechanical environment is altered, which coincides with temporal changes in bone tissue composition. The osteocyte microenvironment is also altered, apoptosis is more prevalent, and hypermineralization occurs. The mechanobiological responses of osteocytes are impaired under estrogen deficiency, which exacerbates osteocyte paracrine regulation of osteoclasts. Recent research reveals changes in osteocytes during estrogen deficiency that may play a critical role in the etiology of the disease. A paradigm change for osteoporosis therapy requires an advanced understanding of such changes to establish the efficacy of osteocyte-targeted therapies to inhibit resorption and secondary mineralization.
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Affiliation(s)
- Laoise M McNamara
- Mechanobiology and Medical Device Research Group, Biomedical Engineering, College of Science and Engineering, National University of Ireland, Galway, Ireland.
- Centre for Research in Medical Devices (CÚRAM), National University of Ireland, Galway, Ireland.
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7
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Adenylyl cyclase 3 regulates osteocyte mechanotransduction and primary cilium. Biochem Biophys Res Commun 2021; 573:145-150. [PMID: 34411897 DOI: 10.1016/j.bbrc.2021.08.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/11/2021] [Indexed: 11/23/2022]
Abstract
Osteocytes are accepted as the primary mechanosensing cell in bone, but how they translate mechanical signals into biochemical signals remains unclear. Adenylyl cyclases (AC) are enzymes that catalyze the production of second messenger cyclic adenosine monophosphate (cAMP). Osteocytes display a biphasic, cAMP response to fluid shear with an initial decrease in cAMP concentrations and then an increased concentration after sustained mechanical stimulation. To date, AC6, a calcium-inhibited AC, is the primary isoform studied in bone. Since osteocytes are calcium-responsive mechanosensors, we asked if a calcium-stimulated isoform contributes to mechanotransduction. Using a transcriptomic dataset of MLO-Y4 osteocyte-like cells from the NIH Gene Expression Omnibus, we identified AC3 as the only calcium-stimulated isoform expressed. We show that inhibiting AC3 in MLO-Y4 cells results in decreased cAMP-signaling with fluid shear and increased osteogenic response to fluid flow (measured as Ptgs2 expression) of longer durations, but not shorter. AC3 likely contributes to osteocyte mechanotransduction through a signaling axis involving the primary cilium and GSK3β. We demonstrate that AC3 localizes to the primary cilium, as well as throughout the cytosol and that fluid-flow regulation of primary cilia length is altered with an AC3 knockdown. Regulation of GSK3β is downstream of the primary cilium and cAMP signaling, and with western blots we found that GSK3β inhibition by phosphorylation is increased after fluid shear in AC3 knockdown groups. Our data show that AC3 contributes to osteocyte mechanotransduction and warrants further investigation to pave the way to identifying new therapeutic targets to treat bone disease like osteoporosis.
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8
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Gould NR, Torre OM, Leser JM, Stains JP. The cytoskeleton and connected elements in bone cell mechano-transduction. Bone 2021; 149:115971. [PMID: 33892173 PMCID: PMC8217329 DOI: 10.1016/j.bone.2021.115971] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/30/2021] [Accepted: 04/17/2021] [Indexed: 02/07/2023]
Abstract
Bone is a mechano-responsive tissue that adapts to changes in its mechanical environment. Increases in strain lead to increased bone mass acquisition, whereas decreases in strain lead to a loss of bone mass. Given that mechanical stress is a regulator of bone mass and quality, it is important to understand how bone cells sense and transduce these mechanical cues into biological changes to identify druggable targets that can be exploited to restore bone cell mechano-sensitivity or to mimic mechanical load. Many studies have identified individual cytoskeletal components - microtubules, actin, and intermediate filaments - as mechano-sensors in bone. However, given the high interconnectedness and interaction between individual cytoskeletal components, and that they can assemble into multiple discreet cellular structures, it is likely that the cytoskeleton as a whole, rather than one specific component, is necessary for proper bone cell mechano-transduction. This review will examine the role of each cytoskeletal element in bone cell mechano-transduction and will present a unified view of how these elements interact and work together to create a mechano-sensor that is necessary to control bone formation following mechanical stress.
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Affiliation(s)
- Nicole R Gould
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Olivia M Torre
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jenna M Leser
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Joseph P Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA..
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9
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Li MCM, Chow SKH, Wong RMY, Qin L, Cheung WH. The role of osteocytes-specific molecular mechanism in regulation of mechanotransduction - A systematic review. J Orthop Translat 2021; 29:1-9. [PMID: 34036041 PMCID: PMC8138679 DOI: 10.1016/j.jot.2021.04.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/15/2021] [Accepted: 04/11/2021] [Indexed: 11/29/2022] Open
Abstract
Background Osteocytes, composing over 90% of bone cells, are well known for their mechanosensing abilities. Aged osteocytes with impaired morphology and function are less efficient in mechanotransduction which will disrupt bone turnover leading to osteoporosis. The aim of this systematic review is to delineate the mechanotransduction mechanism at different stages in order to explore potential target for therapeutic drugs. Methods A systematic literature search was performed in PubMed and Web of Science. Original animal, cell and clinical studies with available English full-text were included. Information was extracted from the included studies for review. Results The 26 studies included in this review provided evidence that mechanical loading are sensed by osteocytes via various sensing proteins and transduced to different signaling molecules which later initiate various biochemical responses. Studies have shown that osteocyte plasma membrane and cytoskeletons are emerging key players in initiating mechanotransduction. Bone regulating genes expressions are altered in response to load sensed by osteocytes, but the genes involved different signaling pathways and the spatiotemporal expression pattern had made mechanotransduction mechanism complicated. Most of the included studies described the important role of osteocytes in pathways that regulate mechanosensing and bone remodeling. Conclusions This systematic review provides an up-to-date insight to different steps of mechanotransduction. A better understanding of the mechanotransduction mechanism is beneficial in search of new potential treatment for osteoporotic patients. By delineating the unique morphology of osteocytes and their interconnected signaling network new targets can be discovered for drug development. Translational potential of this article This systematic review provides an up-to-date sequential overview and highlights the different osteocyte-related pathways and signaling molecules during mechanotransduction. This allows a better understanding of mechanotransduction for future development of new therapeutic interventions to treat patients with impaired mechanosensitivity.
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Affiliation(s)
- Meng Chen Michelle Li
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
| | - Simon Kwoon Ho Chow
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
- The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, PR China
| | - Ronald Man Yeung Wong
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
| | - Ling Qin
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
| | - Wing Hoi Cheung
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
- The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, PR China
- Corresponding author.Department of Orthopaedics and Traumatology, 5/F, Clinical Sciences Building, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
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10
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Geoghegan IP, McNamara LM, Hoey DA. Estrogen withdrawal alters cytoskeletal and primary ciliary dynamics resulting in increased Hedgehog and osteoclastogenic paracrine signalling in osteocytes. Sci Rep 2021; 11:9272. [PMID: 33927279 PMCID: PMC8085225 DOI: 10.1038/s41598-021-88633-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 04/12/2021] [Indexed: 01/02/2023] Open
Abstract
Estrogen deficiency during post-menopausal osteoporosis leads to osteoclastogenesis and bone loss. Increased pro-osteoclastogenic signalling (RANKL/OPG) by osteocytes occurs following estrogen withdrawal (EW) and is associated with impaired focal adhesions (FAs) and a disrupted actin cytoskeleton. RANKL production is mediated by Hedgehog signalling in osteocytes, a signalling pathway associated with the primary cilium, and the ciliary structure is tightly coupled to the cytoskeleton. Therefore, the objective of this study was to investigate the role of the cilium and associated signalling in EW-mediated osteoclastogenic signalling in osteocytes. We report that EW leads to an elongation of the cilium and increase in Hedgehog and osteoclastogenic signalling. Significant trends were identified linking cilia elongation with reductions in cell area and % FA area/cell area, indicating that cilia elongation is associated with disruption of FAs and actin contractility. To verify this, we inhibited FA assembly via αvβ3 antagonism and inhibited actin contractility and demonstrated an elongated cilia and increased expression of Hh markers and Rankl expression. Therefore, our results suggest that the EW conditions associated with osteoporosis lead to a disorganisation of αvβ3 integrins and reduced actin contractility, which were associated with an elongation of the cilium, activation of the Hh pathway and osteoclastogenic paracrine signalling.
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Affiliation(s)
- Ivor P Geoghegan
- Mechanobiology and Medical Devices Research Group, Biomedical Engineering, College of Science and Engineering, National University of Ireland, Galway, Ireland.,Centre for Research in Medical Devices (CÚRAM), National University of Ireland, Galway, Ireland
| | - Laoise M McNamara
- Mechanobiology and Medical Devices Research Group, Biomedical Engineering, College of Science and Engineering, National University of Ireland, Galway, Ireland.,Centre for Research in Medical Devices (CÚRAM), National University of Ireland, Galway, Ireland
| | - David A Hoey
- Centre for Research in Medical Devices (CÚRAM), National University of Ireland, Galway, Ireland. .,Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, D02 R590, Ireland. .,Department of Mechanical, Manufacturing, and Biomedical Engineering, School of Engineering, Trinity College Dublin, Dublin, Ireland. .,Advanced Materials and Bioengineering Research Centre, Trinity College Dublin & RCSI, Dublin 2, Ireland.
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11
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Li YH, Zhu D, Yang T, Cheng L, Sun J, Tan L. Crosstalk between the COX2-PGE2-EP4 signaling pathway and primary cilia in osteoblasts after mechanical stimulation. J Cell Physiol 2020; 236:4764-4777. [PMID: 33275302 DOI: 10.1002/jcp.30198] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 11/09/2020] [Accepted: 11/23/2020] [Indexed: 11/10/2022]
Abstract
Primary cilia have been found to function as mechanosensors in low-magnitude high-frequency vibration (LMHFV)-induced osteogenesis. The PGE2 also regulates bone homeostasis and mechanical osteogenesis through its receptor EP4 signaling, but its involvement in LMHFV-induced or in primary cilia-induced osteogenesis has not been investigated. We hypothesized that LMHFV stimulates osteoblast (OB) differentiation by activating the COX2-PGE2-EP pathway in a manner dependent on primary cilia and that primary cilia are also affected by the PGE2 pathway. In this study, through western blot analysis, RNA interference, enzyme-linked immunosorbent assay, real-time quantitative polymerase chain reaction, and cytochemical staining, we observed that COX2, mPGES-1, and PGE2 levels were markedly elevated in cells treated with LMHFV and were greatly decreased in LMHFV-treated cells following IFT88 silencing. EP4 expression was significantly increased in OBs following LMHFV treatment, but IFT88 silencing significantly blocked this increase. EP4 localized to the bases of primary cilia. LMHFV reduced the length and abundance of primary cilia, but the cells could self-repair their primary cilia after mechanical damage. EP4 antagonism significantly blocked the LMHFV-induced increase in IFT88 expression and blocked the recovery of primary cilia length and the proportion of cells with primary cilia. In addition, COX2 or EP4 antagonism disrupted LMHFV-induced osteogenesis. These results demonstrate the integration of and crosstalk between primary cilia and the COX2-PGE2-EP4 signaling pathway under mechanical stimulation.
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Affiliation(s)
- Yan-Hui Li
- Department of Cardiology and Echocardiography, The First Hospital of Jilin University, Changchun, China
| | - Dong Zhu
- Department of Orthopedic Trauma, The First Hospital of Jilin University, Changchun, China
| | - Tianye Yang
- Department of Plastic and Cosmetic Surgery, The First Hospital of Jilin University, Changchun, China
| | - Long Cheng
- Department of Orthopedic Trauma, The First Hospital of Jilin University, Changchun, China
| | - Jian Sun
- Department of Cardiology, The First Hospital of Jilin University, Changchun, China
| | - Lei Tan
- Department of Orthopedic Trauma, The First Hospital of Jilin University, Changchun, China
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12
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Riffault M, Johnson GP, Owen MM, Javaheri B, Pitsillides AA, Hoey DA. Loss of Adenylyl Cyclase 6 in Leptin Receptor-Expressing Stromal Cells Attenuates Loading-Induced Endosteal Bone Formation. JBMR Plus 2020; 4:e10408. [PMID: 33210061 PMCID: PMC7657397 DOI: 10.1002/jbm4.10408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 08/27/2020] [Indexed: 02/06/2023] Open
Abstract
Bone marrow stromal/stem cells represent a quiescent cell population that replenish the osteoblast bone‐forming cell pool with age and in response to injury, maintaining bone mass and repair. A potent mediator of stromal/stem cell differentiation in vitro and bone formation in vivo is physical loading, yet it still remains unclear whether loading‐induced bone formation requires the osteogenic differentiation of these resident stromal/stem cells. Therefore, in this study, we utilized the leptin receptor (LepR) to identify and trace the contribution of bone marrow stromal cells to mechanoadaptation of bone in vivo. Twelve‐week‐old Lepr‐cre;tdTomato mice were subjected to compressive tibia loading with an 11 N peak load for 40 cycles, every other day for 2 weeks. Histological analysis revealed that Lepr‐cre;tdTomato+ cells arise perinatally around blood vessels and populate bone surfaces as lining cells or osteoblasts before a percentage undergo osteocytogenesis. Lepr‐cre;tdTomato+ stromal cells within the marrow increase in abundance with age, but not following the application of tibial compressive loading. Mechanical loading induces an increase in bone mass and bone formation parameters, yet does not evoke an increase in Lepr‐cre;tdTomato+ osteoblasts or osteocytes. To investigate whether adenylyl cyclase‐6 (AC6) in LepR cells contributes to this mechanoadaptive response, Lepr‐cre;tdTomato mice were further crossed with AC6fl/fl mice to generate a LepR+ cell‐specific knockout of AC6. These Lepr‐cre;tdTomato;AC6fl/fl animals have an attenuated response to compressive tibia loading, characterized by a deficient load‐induced osteogenic response on the endosteal bone surface. This, therefore, shows that Lepr‐cre;tdTomato+ cells contribute to short‐term bone mechanoadaptation. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Mathieu Riffault
- Trinity Centre for Biomedical Engineering Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin Ireland.,Department of Mechanical, Manufacturing, and Biomedical Engineering School of Engineering, Trinity College Dublin Dublin Ireland.,Advanced Materials and Bioengineering Research Centre (AMBER) Royal College of Surgeons in Ireland and Trinity College Dublin Dublin Ireland
| | - Gillian P Johnson
- Trinity Centre for Biomedical Engineering Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin Ireland.,Department of Mechanical, Manufacturing, and Biomedical Engineering School of Engineering, Trinity College Dublin Dublin Ireland.,Advanced Materials and Bioengineering Research Centre (AMBER) Royal College of Surgeons in Ireland and Trinity College Dublin Dublin Ireland.,Department of Mechanical, Aeronautical and Biomedical Engineering University of Limerick Limerick Ireland
| | - Madeline M Owen
- Trinity Centre for Biomedical Engineering Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin Ireland.,Department of Mechanical, Manufacturing, and Biomedical Engineering School of Engineering, Trinity College Dublin Dublin Ireland
| | - Behzad Javaheri
- Skeletal Biology Group, Comparative Biomedical Sciences The Royal Veterinary College London United Kingdom
| | - Andrew A Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences The Royal Veterinary College London United Kingdom
| | - David A Hoey
- Trinity Centre for Biomedical Engineering Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin Ireland.,Department of Mechanical, Manufacturing, and Biomedical Engineering School of Engineering, Trinity College Dublin Dublin Ireland.,Advanced Materials and Bioengineering Research Centre (AMBER) Royal College of Surgeons in Ireland and Trinity College Dublin Dublin Ireland.,Department of Mechanical, Aeronautical and Biomedical Engineering University of Limerick Limerick Ireland
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13
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Simfia I, Schiavi J, McNamara LM. ROCK-II inhibition suppresses impaired mechanobiological responses in early estrogen deficient osteoblasts. Exp Cell Res 2020; 396:112264. [PMID: 32898551 DOI: 10.1016/j.yexcr.2020.112264] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/27/2020] [Accepted: 08/30/2020] [Indexed: 12/22/2022]
Abstract
Mechanobiological responses by osteoblasts are governed by downstream Rho-ROCK signalling through actin cytoskeleton re-arrangements but whether these responses are influenced by estrogen deficiency during osteoporosis remains unknown. The objective of this study was to determine alterations in the mechanobiological responses of estrogen-deficient osteoblasts and investigate whether an inhibitor of the Rho-ROCK signalling can revert these changes. MC3T3-E1 cells were pre-treated with 10 nM 17-β estradiol for 7 days and further cultured with or without estradiol for next 2 days. These cells were treated with or without ROCK-II inhibitor, Y-27632, and oscillatory fluid flow (OFF, 1Pa, 0.5 Hz, 1 h) was applied. Here, we report that Prostaglandin E2 release, Runt-related transcription factor 2 and Osteopontin gene expression were significantly enhanced in response to OFF in estrogen-deficient cells than in cells with estrogen (3.73 vs 1.63 pg/ng DNA; 13.5 vs 2.6 fold, 2.1 vs 0.4 fold respectively). Upon ROCK-II inhibition, these enhanced effects of estrogen deficiency were downregulated. OFF increased the fibril anisotropy in cells pre-treated with estrogen and this increase was suppressed upon ROCK-II inhibition. This study is the first to demonstrate altered mechanobiological responses by osteoblasts during early estrogen deficiency and that these responses to OFF can be suppressed upon ROCK inhibition.
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Affiliation(s)
- Irene Simfia
- Mechanobiology and Medical Device Research Group, Biomechanics Research Centre, Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
| | - Jessica Schiavi
- Mechanobiology and Medical Device Research Group, Biomechanics Research Centre, Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
| | - Laoise M McNamara
- Mechanobiology and Medical Device Research Group, Biomechanics Research Centre, Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland.
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14
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Naqvi SM, Panadero Pérez JA, Kumar V, Verbruggen ASK, McNamara LM. A Novel 3D Osteoblast and Osteocyte Model Revealing Changes in Mineralization and Pro-osteoclastogenic Paracrine Signaling During Estrogen Deficiency. Front Bioeng Biotechnol 2020; 8:601. [PMID: 32656194 PMCID: PMC7326002 DOI: 10.3389/fbioe.2020.00601] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 05/18/2020] [Indexed: 11/13/2022] Open
Abstract
Recent in vitro studies have revealed that the mechanobiological responses of osteoblasts and osteocytes are fundamentally impaired during estrogen deficiency. However, these two-dimensional (2D) cell culture studies do not account for in vivo biophysical cues. Thus, the objectives of this study are to (1) develop a three-dimensional (3D) osteoblast and osteocyte model integrated into a bioreactor and (2) apply this model to investigate whether estrogen deficiency leads to changes in osteoblast to osteocyte transition, mechanosensation, mineralization, and paracrine signaling associated with bone resorption by osteoclasts. MC3T3-E1s were expanded in media supplemented with estrogen (17β-estradiol). These cells were encapsulated in gelatin-mtgase before culture in (1) continued estrogen (E) or (2) no further estrogen supplementation. Constructs were placed in gas permeable and water impermeable cell culture bags and maintained at 5% CO2 and 37°C. These bags were either mechanically stimulated in a custom hydrostatic pressure (HP) bioreactor or maintained under static conditions (control). We report that osteocyte differentiation, characterized by the presence of dendrites and staining for osteocyte marker dentin matrix acidic phosphoprotein 1 (DMP1), was significantly greater under estrogen withdrawal (EW) compared to under continuous estrogen treatment (day 21). Mineralization [bone sialoprotein (BSP), osteopontin (OPN), alkaline phosphatase (ALP), calcium] and gene expression associated with paracrine signaling for osteoclastogenesis [receptor activator of nuclear factor kappa-β ligand (RANKL)/osteoprotegerin OPG ratio] were significantly increased in estrogen deficient and mechanically stimulated cells. Interestingly, BSP and DMP-1 were also increased at day 1 and day 21, respectively, which play a role in regulation of biomineralization. Furthermore, the increase in pro-osteoclastogenic signaling may be explained by altered mechanoresponsiveness of osteoblasts or osteocytes during EW. These findings highlight the impact of estrogen deficiency on bone cell function and provide a novel in vitro model to investigate the mechanisms underpinning changes in bone cells after estrogen deficiency.
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Affiliation(s)
| | | | | | | | - Laoise M. McNamara
- Mechanobiology and Medical Device Research Group, Department of Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
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15
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Qin L, Liu W, Cao H, Xiao G. Molecular mechanosensors in osteocytes. Bone Res 2020; 8:23. [PMID: 32550039 PMCID: PMC7280204 DOI: 10.1038/s41413-020-0099-y] [Citation(s) in RCA: 186] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 04/07/2020] [Accepted: 04/17/2020] [Indexed: 12/11/2022] Open
Abstract
Osteocytes, the most abundant and long-lived cells in bone, are the master regulators of bone remodeling. In addition to their functions in endocrine regulation and calcium and phosphate metabolism, osteocytes are the major responsive cells in force adaptation due to mechanical stimulation. Mechanically induced bone formation and adaptation, disuse-induced bone loss and skeletal fragility are mediated by osteocytes, which sense local mechanical cues and respond to these cues in both direct and indirect ways. The mechanotransduction process in osteocytes is a complex but exquisite regulatory process between cells and their environment, between neighboring cells, and between different functional mechanosensors in individual cells. Over the past two decades, great efforts have focused on finding various mechanosensors in osteocytes that transmit extracellular mechanical signals into osteocytes and regulate responsive gene expression. The osteocyte cytoskeleton, dendritic processes, Integrin-based focal adhesions, connexin-based intercellular junctions, primary cilium, ion channels, and extracellular matrix are the major mechanosensors in osteocytes reported so far with evidence from both in vitro and in vitro studies. This review aims to give a systematic introduction to osteocyte mechanobiology, provide details of osteocyte mechanosensors, and discuss the roles of osteocyte mechanosensitive signaling pathways in the regulation of bone homeostasis.
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Affiliation(s)
- Lei Qin
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
| | - Wen Liu
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
| | - Huiling Cao
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
| | - Guozhi Xiao
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
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16
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Moore ER, Chen JC, Jacobs CR. Prx1-Expressing Progenitor Primary Cilia Mediate Bone Formation in response to Mechanical Loading in Mice. Stem Cells Int 2019; 2019:3094154. [PMID: 31814831 PMCID: PMC6877967 DOI: 10.1155/2019/3094154] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 09/14/2019] [Accepted: 09/26/2019] [Indexed: 11/25/2022] Open
Abstract
Increases in mechanical loading can enhance the addition of new bone, altering geometry and density such that bones better withstand higher forces. Bone-forming osteoblasts have long been thought to originate from progenitors, but the exact source is yet to be identified. Previous studies indicate osteogenic precursors arise from Prx1-expressing progenitors during embryonic development and adult fracture repair. However, it is unknown whether this cell population is also a source for mechanically induced active osteoblasts. We first identified that Prx1 is expressed in skeletally mature mouse periosteum, a thin tissue covering the surface of the bone that is rich in osteoprogenitors. We then traced Prx1 progenitor lineage using a transgenic mouse model carrying both a Prx1-driven tamoxifen-inducible Cre and a ROSA-driven lacZ reporter gene. Cells that expressed Prx1 when compressive axial loading was applied were detected within the cortical bone days after stimulation, indicating osteocytes are of Prx1-expressing cell origin. In addition, we evaluated how these cells sense and respond to physical stimulation in vivo by disrupting their primary cilia, which are antenna-like sensory organelles known to enhance mechanical and chemical signaling kinetics. Although Prx1-driven primary cilium disruption did not affect osteoblast recruitment to the bone surface, the relative mineral apposition and bone formation rates were decreased by 53% and 34%, respectively. Thus, this cell population contributes to load-induced bone formation, and primary cilia are needed for a complete response. Interestingly, Prx1-expressing progenitors are easily extracted from periosteum and are perhaps an attractive alternative to marrow stem cells for bone tissue regeneration strategies.
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Affiliation(s)
- Emily R. Moore
- Department of Biomedical Engineering, Columbia University, 500 W 120th Street New York, NY 10027, USA
| | - Julia C. Chen
- Department of Biomedical Engineering, Columbia University, 500 W 120th Street New York, NY 10027, USA
| | - Christopher R. Jacobs
- Department of Biomedical Engineering, Columbia University, 500 W 120th Street New York, NY 10027, USA
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17
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Hruska KA, Mahjoub MR. New pathogenic insights inform therapeutic target development for renal osteodystrophy. Kidney Int 2019; 95:261-263. [PMID: 30665565 DOI: 10.1016/j.kint.2018.10.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 10/23/2018] [Indexed: 11/28/2022]
Abstract
In an ancillary analysis of cross-sectional observational studies of bone health in end-stage kidney disease (ESKD), Evenepoel et al. reported that subjects with autosomal-dominant polycystic kidney disease (ADPKD) had a unique phenotype in their renal osteodystrophy. ADPKD caused resistance to parathyroid hormone (PTH) producing lower turnover states and preservation of cortical bone mineral density. PTH resistance was probably produced by increased osteocyte sclerostin levels, which is regulated by mechanical loading sensed through primary cilia sensory function affected by mutation in PKD1 and PKD2.
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Affiliation(s)
- Keith A Hruska
- Department of Pediatrics Renal Division Washington University School of Medicine, Saint Louis, Missouri, USA; Department of Medicine Renal Division Washington University School of Medicine, Saint Louis, Missouri, USA; Department of Cell Biology, Washington University School of Medicine, Saint Louis, Missouri, USA.
| | - Moe R Mahjoub
- Department of Medicine Renal Division Washington University School of Medicine, Saint Louis, Missouri, USA; Department of Cell Biology, Washington University School of Medicine, Saint Louis, Missouri, USA
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18
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Johnson GP, Stavenschi E, Eichholz KF, Corrigan MA, Fair S, Hoey DA. Mesenchymal stem cell mechanotransduction is cAMP dependent and regulated by adenylyl cyclase 6 and the primary cilium. J Cell Sci 2018; 131:jcs.222737. [PMID: 30301777 DOI: 10.1242/jcs.222737] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 09/21/2018] [Indexed: 01/24/2023] Open
Abstract
Mechanical loading is a potent stimulus of bone adaptation, requiring the replenishment of the osteoblast from a progenitor population. One such progenitor is the mesenchymal stem cell (MSC), which undergoes osteogenic differentiation in response to oscillatory fluid shear. Yet, the mechanism mediating stem cell mechanotransduction, and thus the potential to target this therapeutically, is poorly understood. In this study, we demonstrate that MSCs utilise cAMP as a second messenger in mechanotransduction, which is required for flow-mediated increases in osteogenic gene expression. Furthermore, we demonstrate that this mechanosignalling is dependent on the primary cilium and the ciliary localised adenylyl cyclase 6. Finally, we also demonstrate that this mechanotransduction mechanism can be targeted therapeutically to enhance cAMP signalling and early osteogenic signalling, mimicking the beneficial effect of physical loading. Our findings therefore demonstrate a novel mechanism of MSC mechanotransduction that can be targeted therapeutically, demonstrating a potential mechanotherapeutic for bone-loss diseases such as osteoporosis.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Gillian P Johnson
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College, Dublin D02 R590, Ireland.,Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2 D02 DK07, Ireland.,Department of Mechanical, Aeronautical and Biomedical Engineering, School of Engineering, University of Limerick, Limerick V94 PH61, Ireland.,Laboratory of Animal Reproduction, Department of Biological Sciences, School of Natural Sciences, Faculty of Science and Engineering, University of Limerick, Limerick V94 T9PX, Ireland
| | - Elena Stavenschi
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College, Dublin D02 R590, Ireland.,Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2 D02 DK07, Ireland
| | - Kian F Eichholz
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College, Dublin D02 R590, Ireland.,Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2 D02 DK07, Ireland
| | - Michele A Corrigan
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College, Dublin D02 R590, Ireland.,Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2 D02 DK07, Ireland
| | - Sean Fair
- Laboratory of Animal Reproduction, Department of Biological Sciences, School of Natural Sciences, Faculty of Science and Engineering, University of Limerick, Limerick V94 T9PX, Ireland
| | - David A Hoey
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College, Dublin D02 R590, Ireland .,Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2 D02 DK07, Ireland.,Department of Mechanical, Aeronautical and Biomedical Engineering, School of Engineering, University of Limerick, Limerick V94 PH61, Ireland.,Advanced Materials and Bioengineering Research Centre, Trinity College Dublin & RCSI, Dublin 2 D02 VN51, Ireland
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19
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Stavenschi E, Corrigan MA, Johnson GP, Riffault M, Hoey DA. Physiological cyclic hydrostatic pressure induces osteogenic lineage commitment of human bone marrow stem cells: a systematic study. Stem Cell Res Ther 2018; 9:276. [PMID: 30359324 PMCID: PMC6203194 DOI: 10.1186/s13287-018-1025-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 08/27/2018] [Accepted: 09/30/2018] [Indexed: 01/12/2023] Open
Abstract
Background Physical loading is necessary to maintain bone tissue integrity. Loading-induced fluid shear is recognised as one of the most potent bone micromechanical cues and has been shown to direct stem cell osteogenesis. However, the effect of pressure transients, which drive fluid flow, on human bone marrow stem cell (hBMSC) osteogenesis is undetermined. Therefore, the objective of the study is to employ a systematic analysis of cyclic hydrostatic pressure (CHP) parameters predicted to occur in vivo on early hBMSC osteogenic responses and late-stage osteogenic lineage commitment. Methods hBMSC were exposed to CHP of 10 kPa, 100 kPa and 300 kPa magnitudes at frequencies of 0.5 Hz, 1 Hz and 2 Hz for 1 h, 2 h and 4 h of stimulation, and the effect on early osteogenic gene expression of COX2, RUNX2 and OPN was determined. Moreover, to decipher whether CHP can induce stem cell lineage commitment, hBMSCs were stimulated for 4 days for 2 h/day using 10 kPa, 100 kPa and 300 kPa pressures at 2 Hz frequency and cultured statically for an additional 1–2 weeks. Pressure-induced osteogenesis was quantified based on ATP release, collagen synthesis and mineral deposition. Results CHP elicited a positive, but variable, early osteogenic response in hBMSCs in a magnitude- and frequency-dependent manner, that is gene specific. COX2 expression elicited magnitude-dependent effects which were not present for RUNX2 or OPN mRNA expression. However, the most robust pro-osteogenic response was found at the highest magnitude (300 kPa) and frequency regimes (2 Hz). Interestingly, long-term mechanical stimulation utilising 2 Hz frequency elicited a magnitude-dependent release of ATP; however, all magnitudes promoted similar levels of collagen synthesis and significant mineral deposition, demonstrating that lineage commitment is magnitude independent. This therefore demonstrates that physiological levels of pressures, as low as 10 kPa, within the bone can drive hBMSC osteogenic lineage commitment. Conclusion Overall, these findings demonstrate an important role for cyclic hydrostatic pressure in hBMSCs and bone mechanobiology, which should be considered when studying pressure-driven fluid shear effects in hBMSCs mechanobiology. Moreover, these findings may have clinical implication in terms of bioreactor-based bone tissue engineering strategies. Electronic supplementary material The online version of this article (10.1186/s13287-018-1025-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elena Stavenschi
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.,Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland
| | - Michele A Corrigan
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.,Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland
| | - Gillian P Johnson
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.,Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland.,Department of Mechanical, Aeronautical and Biomedical Engineering, University of Limerick, Limerick, Ireland
| | - Mathieu Riffault
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.,Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland.,Advanced Materials and Bioengineering Research Centre, Trinity College Dublin and RCSI, Dublin 2, Ireland
| | - David A Hoey
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland. .,Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland. .,Department of Mechanical, Aeronautical and Biomedical Engineering, University of Limerick, Limerick, Ireland. .,Advanced Materials and Bioengineering Research Centre, Trinity College Dublin and RCSI, Dublin 2, Ireland.
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20
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Moore ER, Zhu YX, Ryu HS, Jacobs CR. Periosteal progenitors contribute to load-induced bone formation in adult mice and require primary cilia to sense mechanical stimulation. Stem Cell Res Ther 2018; 9:190. [PMID: 29996901 PMCID: PMC6042447 DOI: 10.1186/s13287-018-0930-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 06/11/2018] [Accepted: 06/14/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The fully developed adult skeleton adapts to mechanical forces by generating more bone, usually at the periosteal surface. Progenitor cells in the periosteum are believed to differentiate into bone-forming osteoblasts that contribute to load-induced adult bone formation, but in vivo evidence does not yet exist. Furthermore, the mechanism by which periosteal progenitors might sense physical loading and trigger differentiation is unknown. We propose that periosteal osteochondroprogenitors (OCPs) directly sense mechanical load and differentiate into bone-forming osteoblasts via their primary cilia, mechanosensory organelles known to be involved in osteogenic differentiation. METHODS We generated a diphtheria toxin ablation mouse model and performed ulnar loading and dynamic histomorphometry to quantify the contribution of periosteal OCPs in adult bone formation in vivo. We also generated a primary cilium knockout model and isolated periosteal cells to study the role of the cilium in periosteal OCP mechanosensing in vitro. Experimental groups were compared using one-way analysis of variance or student's t test, and sample size was determined to achieve a minimum power of 80%. RESULTS Mice without periosteal OCPs had severely attenuated mechanically induced bone formation and lacked the mineralization necessary for daily skeletal maintenance. Our in vitro results demonstrate that OCPs in the periosteum uniquely sense fluid shear and exhibit changes in osteogenic markers consistent with osteoblast differentiation; however, this response is essentially lost when the primary cilium is absent. CONCLUSIONS Combined, our data show that periosteal progenitors are a mechanosensitive cell source that significantly contribute to adult skeletal maintenance. More importantly, an OCP population persists in the adult skeleton and these cells, as well as their cilia, are promising targets for bone regeneration strategies.
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Affiliation(s)
- Emily R. Moore
- Columbia University Department of Biomedical Engineering, 500 W 120th St, New York, NY 10027 USA
| | - Ya Xing Zhu
- Columbia University Department of Biomedical Engineering, 500 W 120th St, New York, NY 10027 USA
| | - Han Seul Ryu
- Columbia University Department of Biomedical Engineering, 500 W 120th St, New York, NY 10027 USA
| | - Christopher R. Jacobs
- Columbia University Department of Biomedical Engineering, 500 W 120th St, New York, NY 10027 USA
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21
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Moore ER, Ryu HS, Zhu YX, Jacobs CR. Adenylyl cyclases and TRPV4 mediate Ca 2+/cAMP dynamics to enhance fluid flow-induced osteogenesis in osteocytes. JOURNAL OF MOLECULAR BIOCHEMISTRY 2018; 7:48-59. [PMID: 31123666 PMCID: PMC6529196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Bone adapts to physical forces and this process is dependent on osteocyte mechanotransduction. One way osteocytes sense mechanical stimulation is through the primary cilium, a sensory organelle that triggers intracellular signaling cascades in response to fluid shear. Our lab previously determined that flow-induced ciliary Ca2+ influx and changes in cytosolic cAMP levels are critical for osteogenesis. We also identified two proteins important for osteocyte mechanotransduction: transient receptor potential vanilloid 4 (TRPV4) and adenylyl cyclase 6 (AC6). Interestingly, disrupting the Ca2+-binding ability of these proteins results in loss of function. Although knockdowns of TRPV4 and AC6 disrupt osteogenesis, there is no definitive evidence linking them to Ca2+/cAMP dynamics that facilitate osteocyte mechanotransduction. We therefore transfected MLO-Y4 osteocytes with AC3/6 and TRPV4 overexpression plasmids that fail to interact with Ca2+ and observed the response to fluid shear. Indeed, mutant groups exhibited adverse changes in cAMP and lower mRNA expression of an osteogenic marker, COX-2, at the onset of flow. This pattern persisted for AC3 and TRPV4 but we detected no difference in AC6 at longer exposure to flow. These results suggest TRPV4 and ACs mediate Ca2+/cAMP dynamics that are important for osteocyte mechanotransduction. These mechanisms are potential targets for therapeutics to combat bone loss and should be investigated further.
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22
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Spasic M, Jacobs CR. Primary cilia: Cell and molecular mechanosensors directing whole tissue function. Semin Cell Dev Biol 2017; 71:42-52. [PMID: 28843978 PMCID: PMC5922257 DOI: 10.1016/j.semcdb.2017.08.036] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 08/15/2017] [Accepted: 08/18/2017] [Indexed: 01/09/2023]
Abstract
Primary cilia are immotile, microtubule-based organelles extending from the surface of nearly every mammalian cell. Mechanical stimulation causes deflection of the primary cilium, initiating downstream signaling cascades to the rest of the cell. The cilium forms a unique subcellular microdomain, and defects in ciliary protein composition or physical structure have been associated with a myriad of human pathologies. In this review, we discuss the importance of ciliary mechanotransduction at the cell and tissue level, and how furthering our molecular understanding of primary cilia mechanobiology may lead to therapeutic strategies to treat human diseases.
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Affiliation(s)
- Milos Spasic
- Columbia University, Department of Biomedical Engineering, United States.
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23
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Dessauer CW, Watts VJ, Ostrom RS, Conti M, Dove S, Seifert R. International Union of Basic and Clinical Pharmacology. CI. Structures and Small Molecule Modulators of Mammalian Adenylyl Cyclases. Pharmacol Rev 2017; 69:93-139. [PMID: 28255005 PMCID: PMC5394921 DOI: 10.1124/pr.116.013078] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Adenylyl cyclases (ACs) generate the second messenger cAMP from ATP. Mammalian cells express nine transmembrane AC (mAC) isoforms (AC1-9) and a soluble AC (sAC, also referred to as AC10). This review will largely focus on mACs. mACs are activated by the G-protein Gαs and regulated by multiple mechanisms. mACs are differentially expressed in tissues and regulate numerous and diverse cell functions. mACs localize in distinct membrane compartments and form signaling complexes. sAC is activated by bicarbonate with physiologic roles first described in testis. Crystal structures of the catalytic core of a hybrid mAC and sAC are available. These structures provide detailed insights into the catalytic mechanism and constitute the basis for the development of isoform-selective activators and inhibitors. Although potent competitive and noncompetitive mAC inhibitors are available, it is challenging to obtain compounds with high isoform selectivity due to the conservation of the catalytic core. Accordingly, caution must be exerted with the interpretation of intact-cell studies. The development of isoform-selective activators, the plant diterpene forskolin being the starting compound, has been equally challenging. There is no known endogenous ligand for the forskolin binding site. Recently, development of selective sAC inhibitors was reported. An emerging field is the association of AC gene polymorphisms with human diseases. For example, mutations in the AC5 gene (ADCY5) cause hyperkinetic extrapyramidal motor disorders. Overall, in contrast to the guanylyl cyclase field, our understanding of the (patho)physiology of AC isoforms and the development of clinically useful drugs targeting ACs is still in its infancy.
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Affiliation(s)
- Carmen W Dessauer
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas (C.W.D.); Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (V.J.W.); Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (R.S.O.); Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (M.C.); Institute of Pharmacy, University of Regensburg, Regensburg, Germany (S.D.); and Institute of Pharmacology, Hannover Medical School, Hannover, Germany (R.S.)
| | - Val J Watts
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas (C.W.D.); Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (V.J.W.); Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (R.S.O.); Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (M.C.); Institute of Pharmacy, University of Regensburg, Regensburg, Germany (S.D.); and Institute of Pharmacology, Hannover Medical School, Hannover, Germany (R.S.)
| | - Rennolds S Ostrom
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas (C.W.D.); Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (V.J.W.); Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (R.S.O.); Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (M.C.); Institute of Pharmacy, University of Regensburg, Regensburg, Germany (S.D.); and Institute of Pharmacology, Hannover Medical School, Hannover, Germany (R.S.)
| | - Marco Conti
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas (C.W.D.); Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (V.J.W.); Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (R.S.O.); Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (M.C.); Institute of Pharmacy, University of Regensburg, Regensburg, Germany (S.D.); and Institute of Pharmacology, Hannover Medical School, Hannover, Germany (R.S.)
| | - Stefan Dove
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas (C.W.D.); Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (V.J.W.); Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (R.S.O.); Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (M.C.); Institute of Pharmacy, University of Regensburg, Regensburg, Germany (S.D.); and Institute of Pharmacology, Hannover Medical School, Hannover, Germany (R.S.)
| | - Roland Seifert
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas (C.W.D.); Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (V.J.W.); Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (R.S.O.); Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (M.C.); Institute of Pharmacy, University of Regensburg, Regensburg, Germany (S.D.); and Institute of Pharmacology, Hannover Medical School, Hannover, Germany (R.S.)
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Abstract
The primary cilium is a mechanosensor in a variety of mammalian cell types, initiating and directing intracellular signalling cascades in response to external stimuli. When primary cilia formation is disrupted, cells have diminished mechanosensitivity and an abrogated response to mechanical stimulation. Due to this important role, we hypothesised that increasing primary cilia length would enhance the downstream response and therefore, mechanosensitivity. To test this hypothesis, we increased osteocyte primary cilia length with fenoldopam and lithium and found that cells with longer primary cilia were more mechanosensitive. Furthermore, fenoldopam treatment potentiated adenylyl cyclase activity and was able to recover primary cilia form and sensitivity in cells with impaired cilia. This work demonstrates that modulating the structure of the primary cilium directly impacts cellular mechanosensitivity. Our results implicate cilium length as a potential therapeutic target for combating numerous conditions characterised by impaired cilia function.
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Qiu L, LeBel RP, Storm DR, Chen X. Type 3 adenylyl cyclase: a key enzyme mediating the cAMP signaling in neuronal cilia. INTERNATIONAL JOURNAL OF PHYSIOLOGY, PATHOPHYSIOLOGY AND PHARMACOLOGY 2016; 8:95-108. [PMID: 27785336 PMCID: PMC5078481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 09/06/2016] [Indexed: 06/06/2023]
Abstract
Cilia are rigid, centriole-derived, microtubule-based organelles present in a majority of vertebrate cells including neurons. They are considered the cellular "antennae" attuned for detecting a range of extracellular signals including photons, odorants, morphogens, hormones and mechanical forces. The ciliary microenvironment is distinct from most actin-based subcellular structures such as microvilli or synapses. In the nervous system, there is no evidence that neuronal cilia process any synaptic structure. Apparently, the structural features of neuronal cilia do not allow them to harbor any synaptic connections. Nevertheless, a large number of G protein-coupled receptors (GPCRs) including odorant receptors, rhodopsin, Smoothened, and type 6 serotonin receptor are found in cilia, suggesting that these tiny processes largely depend on metabotropic receptors and their tuned signals to impact neuronal functions. The type 3 adenylyl cyclase (AC3), widely known as a cilia marker, is highly and predominantly expressed in olfactory sensory cilia and primary cilia throughout the brain. We discovered that ablation of AC3 in mice leads to pleiotropic phenotypes including anosmia, failure to detect mechanical stimulation of airflow, cognitive deficit, obesity, and depression-like behaviors. Multiple lines of human genetic evidence also demonstrate that AC3 is associated with obesity, major depressive disorder (MDD), sarcoidosis, and infertility, underscoring its functional importance. Here we review recent progress on AC3, a key enzyme mediating the cAMP signaling in neuronal cilia.
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Affiliation(s)
- Liyan Qiu
- Department of Molecular, Cellular, and Biomedical Sciences, College of Life Science and Agriculture, University of New HampshireDurham, NH 03824, USA
| | - Robert P LeBel
- Department of Molecular, Cellular, and Biomedical Sciences, College of Life Science and Agriculture, University of New HampshireDurham, NH 03824, USA
| | - Daniel R Storm
- Department of Pharmacology, School of Medicine, University of WashingtonSeattle, WA, 98195-7750, USA
| | - Xuanmao Chen
- Department of Molecular, Cellular, and Biomedical Sciences, College of Life Science and Agriculture, University of New HampshireDurham, NH 03824, USA
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26
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Abstract
Skeletal loading is an important physiological regulator of bone mass. Theoretically, mechanical forces or administration of drugs that activate bone mechanosensors would be a novel treatment for osteoporotic disorders, particularly age-related osteoporosis and other bone loss caused by skeletal unloading. Uncertainty regarding the identity of the molecular targets that sense and transduce mechanical forces in bone, however, has limited the therapeutic exploitation of mechanosesning pathways to control bone mass. Recently, two evolutionally conserved mechanosensing pathways have been shown to function as "physical environment" sensors in cells of the osteoblasts lineage. Indeed, polycystin-1 (Pkd1, or PC1) and polycystin-2 (Pkd2, or PC2' or TRPP2), which form a flow sensing receptor channel complex, and TAZ (transcriptional coactivator with PDZ-binding motif, or WWTR1), which responds to the extracellular matrix microenvironment act in concert to reciprocally regulate osteoblastogenesis and adipogenesis through co-activating Runx2 and a co-repressing PPARγ activities. Interactions of polycystins and TAZ with other putative mechanosensing mechanism, such as primary cilia, integrins and hemichannels, may create multifaceted mechanosensing networks in bone. Moreover, modulation of polycystins and TAZ interactions identify novel molecular targets to develop small molecules that mimic the effects of mechanical loading on bone.
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Affiliation(s)
- Zhousheng Xiao
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN 38165, USA
| | - Leigh Darryl Quarles
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN 38165, USA
- Coleman College of Medicine Building, Suite B216, University of Tennessee Health Science Center, 956 Court Avenue, Memphis, TN 38163, USA
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27
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Yuan X, Serra RA, Yang S. Function and regulation of primary cilia and intraflagellar transport proteins in the skeleton. Ann N Y Acad Sci 2015; 1335:78-99. [PMID: 24961486 PMCID: PMC4334369 DOI: 10.1111/nyas.12463] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Primary cilia are microtubule-based organelles that project from the cell surface to enable transduction of various developmental signaling pathways. The process of intraflagellar transport (IFT) is crucial for the building and maintenance of primary cilia. Ciliary dysfunction has been found in a range of disorders called ciliopathies, some of which display severe skeletal dysplasias. In recent years, interest has grown in uncovering the function of primary cilia/IFT proteins in bone development, mechanotransduction, and cellular regulation. We summarize recent advances in understanding the function of cilia and IFT proteins in the regulation of cell differentiation in osteoblasts, osteocytes, chondrocytes, and mesenchymal stem cells (MSCs). We also discuss the mechanosensory function of cilia and IFT proteins in bone cells, cilia orientation, and other functions of cilia in chondrocytes.
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Affiliation(s)
- Xue Yuan
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, The State University of New York, Buffalo, NY
| | - Rosa A. Serra
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Shuying Yang
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, The State University of New York, Buffalo, NY
- Developmental Genomics Group, New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, The State University of New York, Buffalo, NY
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28
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Drexler S, Wann A, Vincent TL. Are cellular mechanosensors potential therapeutic targets in osteoarthritis? ACTA ACUST UNITED AC 2014. [DOI: 10.2217/ijr.14.15] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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