1
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Franceschi RT, Hallett SA, Ge C. Discoidin domain receptors; an ancient family of collagen receptors has major roles in bone development, regeneration and metabolism. FRONTIERS IN DENTAL MEDICINE 2023; 4:1181817. [PMID: 38222874 PMCID: PMC10785288 DOI: 10.3389/fdmed.2023.1181817] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024] Open
Abstract
The extracellular matrix (ECM) niche plays a critical role in determining cellular behavior during bone development including the differentiation and lineage allocation of skeletal progenitor cells to chondrocytes, osteoblasts, or marrow adipocytes. As the major ECM component in mineralized tissues, collagen has instructive as well as structural roles during bone development and is required for bone cell differentiation. Cells sense their extracellular environment using specific cell surface receptors. For many years, specific β1 integrins were considered the main collagen receptors in bone, but, more recently, the important role of a second, more primordial collagen receptor family, the discoidin domain receptors, has become apparent. This review will specifically focus on the roles of discoidin domain receptors in mineralized tissue development as well as related functions in abnormal bone formation, regeneration and metabolism.
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Affiliation(s)
- Renny T. Franceschi
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, United States
| | - Shawn A. Hallett
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, United States
| | - Chunxi Ge
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, United States
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2
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Role of Primary Cilia in Skeletal Disorders. Stem Cells Int 2022; 2022:6063423. [PMID: 35761830 PMCID: PMC9233574 DOI: 10.1155/2022/6063423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 05/23/2022] [Accepted: 06/03/2022] [Indexed: 11/26/2022] Open
Abstract
Primary cilia are highly conserved microtubule-based organelles that project from the cell surface into the extracellular environment and play important roles in mechanosensation, mechanotransduction, polarity maintenance, and cell behaviors during organ development and pathological changes. Intraflagellar transport (IFT) proteins are essential for cilium formation and function. The skeletal system consists of bones and connective tissue, including cartilage, tendons, and ligaments, providing support, stability, and movement to the body. Great progress has been achieved in primary cilia and skeletal disorders in recent decades. Increasing evidence suggests that cells with cilium defects in the skeletal system can cause numerous human diseases. Moreover, specific deletion of ciliary proteins in skeletal tissues with different Cre mice resulted in diverse malformations, suggesting that primary cilia are involved in the development of skeletal diseases. In addition, the intact of primary cilium is essential to osteogenic/chondrogenic induction of mesenchymal stem cells, regarded as a promising target for clinical intervention for skeletal disorders. In this review, we summarized the role of primary cilia and ciliary proteins in the pathogenesis of skeletal diseases, including osteoporosis, bone/cartilage tumor, osteoarthritis, intervertebral disc degeneration, spine scoliosis, and other cilium-related skeletal diseases, and highlighted their promising treatment methods, including using mesenchymal stem cells. Our review tries to present evidence for primary cilium as a promising target for clinical intervention for skeletal diseases.
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3
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Chatterjee M, Muljadi PM, Andarawis-Puri N. The role of the tendon ECM in mechanotransduction: disruption and repair following overuse. Connect Tissue Res 2022; 63:28-42. [PMID: 34030531 DOI: 10.1080/03008207.2021.1925663] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Purpose: Tendon overuse injuries are prevalent conditions with limited therapeutic options to halt disease progression. The specialized extracellular matrix (ECM) both enables joint function and mediates mechanical signals to tendon cells, driving biological responses to exercise or injury. With overuse, tendon ECM composition and structure changes at multiple scales, disrupting mechanotransduction and resulting in inadequate repair and disease progression. This review highlights the multiscale ECM changes that occur with tendon overuse and corresponding effects on cell-matrix interactions and cellular response to load.Results: Different functional joint requirements and tendon types experience a wide range of loading profiles, creating varied downstream mechanical stimuli. Distinct ECM structure and mechanical properties within the fascicle matrix, interfascicle matrix, and enthesis and their varied disruption with overuse are considered. The pericellular matrix (PCM) comprising the microscale tendon cell environment has a unique composition that changes with overuse injury and exercise, suggesting an important role in mechanotransduction and promoting repair. Cell-matrix interactions are mediated by structures including cilia, integrins, connexins and cytoskeleton that signal downstream homeostasis, adaptation, or repair. ECM disruption with tendon overuse may cause altered mechanical loading and cell-matrix interactions, resulting in mechanobiological understimulation, apoptosis, and ineffective repair. Current interventions to promote repair of tendon overuse injuries including exercise, targeting cell signaling, and modulating inflammation are considered.Conclusion: Future therapeutics should be assessed with regard of their effects on multiscale mechanotransduction in addition to joint function, with consideration of the central role of ECM.
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Affiliation(s)
- Monideepa Chatterjee
- Nancy E. And Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Patrick M Muljadi
- Nancy E. And Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Nelly Andarawis-Puri
- Nancy E. And Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA.,Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York, USA.,Hospital for Special Surgery, New York, New York, USA
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4
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Delaine-Smith RM, Hann AJ, Green NH, Reilly GC. Electrospun Fiber Alignment Guides Osteogenesis and Matrix Organization Differentially in Two Different Osteogenic Cell Types. Front Bioeng Biotechnol 2021; 9:672959. [PMID: 34760876 PMCID: PMC8573409 DOI: 10.3389/fbioe.2021.672959] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 06/08/2021] [Indexed: 11/18/2022] Open
Abstract
Biomimetic replication of the structural anisotropy of musculoskeletal tissues is important to restore proper tissue mechanics and function. Physical cues from the local micro-environment, such as matrix fiber orientation, may influence the differentiation and extracellular matrix (ECM) organization of osteogenic progenitor cells. This study investigates how scaffold fiber orientation affects the behavior of mature and progenitor osteogenic cells, the influence on secreted mineralized-collagenous matrix organization, and the resulting construct mechanical properties. Gelatin-coated electrospun poly(caprolactone) fibrous scaffolds were fabricated with either a low or a high degree of anisotropy and cultured with mature osteoblasts (MLO-A5s) or osteogenic mesenchymal progenitor cells (hES-MPs). For MLO-A5 cells, alkaline phosphatase (ALP) activity was highest, and more calcium-containing matrix was deposited onto aligned scaffolds. In contrast, hES-MPs, osteogenic mesenchymal progenitor cells, exhibited higher ALP activity, collagen, and calcium deposition on randomly orientated fibers compared with aligned counterparts. Deposited matrix was isotropic on random fibrous scaffolds, whereas a greater degree of anisotropy was observed in aligned fibrous constructs, as confirmed by second harmonic generation (SHG) and scanning electron microscope (SEM) imaging. This resulted in anisotropic mechanical properties on aligned constructs. This study indicates that mineralized-matrix deposition by osteoblasts can be controlled by scaffold alignment but that the early stages of osteogenesis may not benefit from culture on orientated scaffolds.
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Affiliation(s)
- Robin M. Delaine-Smith
- Department of Materials Science and Engineering, Kroto Research Institute, University of Sheffield, Sheffield, United Kingdom
| | - Alice Jane Hann
- Department of Materials Science and Engineering, Kroto Research Institute, University of Sheffield, Sheffield, United Kingdom
- Department of Materials Science and Engineering, INSIGNEO Institute for in silico Medicine, University of Sheffield, Sheffield, United Kingdom
| | - Nicola H. Green
- Department of Materials Science and Engineering, Kroto Research Institute, University of Sheffield, Sheffield, United Kingdom
- Department of Materials Science and Engineering, INSIGNEO Institute for in silico Medicine, University of Sheffield, Sheffield, United Kingdom
| | - Gwendolen Clair Reilly
- Department of Materials Science and Engineering, Kroto Research Institute, University of Sheffield, Sheffield, United Kingdom
- Department of Materials Science and Engineering, INSIGNEO Institute for in silico Medicine, University of Sheffield, Sheffield, United Kingdom
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5
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Shea CA, Murphy P. The Primary Cilium on Cells of Developing Skeletal Rudiments; Distribution, Characteristics and Response to Mechanical Stimulation. Front Cell Dev Biol 2021; 9:725018. [PMID: 34490272 PMCID: PMC8418538 DOI: 10.3389/fcell.2021.725018] [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] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 07/27/2021] [Indexed: 12/22/2022] Open
Abstract
Embryo movement is important for tissue differentiation and the formation of functional skeletal elements during embryonic development: reduced mechanical stimulation results in fused joints and misshapen skeletal rudiments with concomitant changes in the signaling environment and gene expression profiles in both mouse and chick immobile embryos. Despite the clear relationship between movement and skeletogenesis, the precise mechanisms by which mechanical stimuli influence gene regulatory processes are not clear. The primary cilium enables cells to sense mechanical stimuli in the cellular environment, playing a crucial mechanosensory role during kidney development and in articular cartilage and bone but little is known about cilia on developing skeletal tissues. Here, we examine the occurrence, length, position, and orientation of primary cilia across developing skeletal rudiments in mouse embryos during a period of pronounced mechanosensitivity and we report differences and similarities between wildtype and muscle-less mutant (Pax3Spd/Spd) rudiments. Strikingly, joint regions tend to have cilia positioned and oriented away from the joint, while there was a less obvious, but still significant, preferred position on the posterior aspect of cells within the proliferative and hypertrophic zones. Regions of the developing rudiments have characteristic proportions of ciliated cells, with more cilia in the resting and joint zones. Comparing wildtype to muscle-less mutant embryos, cilia are shorter in the mutant with no significant difference in the proportion of ciliated cells. Cilia at the mutant joint were also oriented away from the joint line.
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Affiliation(s)
- Claire A Shea
- Trinity College Dublin, The University of Dublin, Dublin, Ireland
| | - Paula Murphy
- Trinity College Dublin, The University of Dublin, Dublin, Ireland
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6
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Luesma MJ, Cantarero I, Sánchez‐Cano AI, Rodellar C, Junquera C. Ultrastructural evidence for telocytes in equine tendon. J Anat 2021; 238:527-535. [PMID: 33070316 PMCID: PMC7855077 DOI: 10.1111/joa.13335] [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: 12/18/2019] [Revised: 09/17/2020] [Accepted: 09/21/2020] [Indexed: 12/24/2022] Open
Abstract
The three-dimensional ultrastructure of the tendon is complex. Two main cell types are classically supported: elongated tenocytes and ovoid tenoblasts. The existence of resident stem/progenitor cells in human and equine tendons has been demonstrated, but their location and relationship to tenoblasts and tenocytes remain unclear. Hence, in this work, we carried out an ultrastructural study of the equine superficial digital flexor tendon. Although the fine structure of tendons has been previously studied using electron microscopy, the presence of telocytes, a specific type of interstitial cell, has not been described thus far. We show the presence of telocytes in the equine inter-fascicular tendon matrix near blood vessels. These telocytes have characteristic telopodes, which are composed of alternating dilated portions (podoms) and thin segments (podomers). Additionally, we demonstrate the presence of the primary cilium in telocytes and its ability to release exosomes. The location of telocytes is similar to that of tendon stem cells. The telocyte-blood vessel proximity, the presence of primary immotile cilia and the release of exosomes could have special significance for tendon homeostasis.
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Affiliation(s)
- María J. Luesma
- Department of Human Anatomy and HistologyUniversity of ZaragozaZaragozaSpain
| | - Irene Cantarero
- Morphological Sciences DepartmentUniversity of CórdobaCórdobaSpain
| | | | - Clementina Rodellar
- Laboratory of Biochemical Genetics (Lagenbio)University of ZaragozaZaragozaSpain
| | - Concepción Junquera
- Department of Human Anatomy and HistologyUniversity of ZaragozaZaragozaSpain
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7
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Lee KH. Involvement of Wnt signaling in primary cilia assembly and disassembly. FEBS J 2020; 287:5027-5038. [PMID: 33015954 DOI: 10.1111/febs.15579] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/21/2020] [Accepted: 09/29/2020] [Indexed: 11/28/2022]
Abstract
The primary cilium is a nonmotile microtubule-based structure, which functions as an antenna-like cellular sensing organelle. The primary cilium is assembled from the basal body, a mother centriole-based structure, during interphase or a quiescent cell stage, and rapidly disassembles before entering mitosis in a dynamic cycle. Defects in this ciliogenesis dynamics are associated with human diseases such as ciliopathy and cancer, but the molecular mechanisms of the ciliogenesis dynamics are still largely unknown. To date, various cellular signaling pathways associated with primary cilia have been proposed, but the main signaling pathways regulating primary cilia assembly/disassembly remain enigmatic. This review describes recent findings in Wnt-induced primary cilia assembly/disassembly and potential future directions for the study of the cellular signaling related to the primary ciliogenesis dynamics.
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Affiliation(s)
- Kyung Ho Lee
- Anticancer Agent Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Ochang, Korea
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8
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Barsch F, Niedermair T, Mamilos A, Schmitt VH, Grevenstein D, Babel M, Burgoyne T, Shoemark A, Brochhausen C. Physiological and Pathophysiological Aspects of Primary Cilia-A Literature Review with View on Functional and Structural Relationships in Cartilage. Int J Mol Sci 2020; 21:ijms21144959. [PMID: 32674266 PMCID: PMC7404129 DOI: 10.3390/ijms21144959] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 02/06/2023] Open
Abstract
Cilia are cellular organelles that project from the cell. They occur in nearly all non-hematopoietic tissues and have different functions in different tissues. In mesenchymal tissues primary cilia play a crucial role in the adequate morphogenesis during embryological development. In mature articular cartilage, primary cilia fulfil chemo- and mechanosensitive functions to adapt the cellular mechanisms on extracellular changes and thus, maintain tissue homeostasis and morphometry. Ciliary abnormalities in osteoarthritic cartilage could represent pathophysiological relationships between ciliary dysfunction and tissue deformation. Nevertheless, the molecular and pathophysiological relationships of ‘Primary Cilia’ (PC) in the context of osteoarthritis is not yet fully understood. The present review focuses on the current knowledge about PC and provide a short but not exhaustive overview of their role in cartilage.
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Affiliation(s)
- Friedrich Barsch
- Institute of Pathology, University Regensburg, 93053 Regensburg, Germany and Institute of Exercise and Occupational Medicine, Department of Medicine, University of Freiburg, 79106 Freiburg, Germany;
| | - Tanja Niedermair
- Institute of Pathology, University Regensburg, 93053 Regensburg, Germany; (T.N.); (A.M.); (M.B.)
| | - Andreas Mamilos
- Institute of Pathology, University Regensburg, 93053 Regensburg, Germany; (T.N.); (A.M.); (M.B.)
| | - Volker H. Schmitt
- Cardiology I, Centre for Cardiology, University Medical Centre, Johannes Gutenberg University of Mainz, 55122 Mainz, Germany;
| | - David Grevenstein
- Department for Orthopedic and Trauma Surgery, University of Cologne, 50923 Köln, Germany;
| | - Maximilian Babel
- Institute of Pathology, University Regensburg, 93053 Regensburg, Germany; (T.N.); (A.M.); (M.B.)
| | - Thomas Burgoyne
- Royal Brompton Hospital and Harefield NHS Trust, SW3 6NP London and UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK;
| | - Amelia Shoemark
- Royal Brompton Hospital and Harefield NHS Trust, University of Dundee, Dundee DD1 4HN, UK;
| | - Christoph Brochhausen
- Institute of Pathology, University Regensburg, 93053 Regensburg, Germany; (T.N.); (A.M.); (M.B.)
- Correspondence: ; Tel.: +49-941-944-6636
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9
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Regulation of the Extracellular Matrix by Ciliary Machinery. Cells 2020; 9:cells9020278. [PMID: 31979260 PMCID: PMC7072529 DOI: 10.3390/cells9020278] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/13/2020] [Accepted: 01/19/2020] [Indexed: 12/14/2022] Open
Abstract
The primary cilium is an organelle involved in cellular signalling. Mutations affecting proteins involved in cilia assembly or function result in diseases known as ciliopathies, which cause a wide variety of phenotypes across multiple tissues. These mutations disrupt various cellular processes, including regulation of the extracellular matrix. The matrix is important for maintaining tissue homeostasis through influencing cell behaviour and providing structural support; therefore, the matrix changes observed in ciliopathies have been implicated in the pathogenesis of these diseases. Whilst many studies have associated the cilium with processes that regulate the matrix, exactly how these matrix changes arise is not well characterised. This review aims to bring together the direct and indirect evidence for ciliary regulation of matrix, in order to summarise the possible mechanisms by which the ciliary machinery could regulate the composition, secretion, remodelling and organisation of the matrix.
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10
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R Ferreira R, Fukui H, Chow R, Vilfan A, Vermot J. The cilium as a force sensor-myth versus reality. J Cell Sci 2019; 132:132/14/jcs213496. [PMID: 31363000 DOI: 10.1242/jcs.213496] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cells need to sense their mechanical environment during the growth of developing tissues and maintenance of adult tissues. The concept of force-sensing mechanisms that act through cell-cell and cell-matrix adhesions is now well established and accepted. Additionally, it is widely believed that force sensing can be mediated through cilia. Yet, this hypothesis is still debated. By using primary cilia sensing as a paradigm, we describe the physical requirements for cilium-mediated mechanical sensing and discuss the different hypotheses of how this could work. We review the different mechanosensitive channels within the cilium, their potential mode of action and their biological implications. In addition, we describe the biological contexts in which cilia are acting - in particular, the left-right organizer - and discuss the challenges to discriminate between cilium-mediated chemosensitivity and mechanosensitivity. Throughout, we provide perspectives on how quantitative analysis and physics-based arguments might help to better understand the biological mechanisms by which cells use cilia to probe their mechanical environment.
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Affiliation(s)
- Rita R Ferreira
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France
| | - Hajime Fukui
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France
| | - Renee Chow
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France
| | - Andrej Vilfan
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), Department of Living Matter Physics, 37077 Göttingen, Germany .,J. Stefan Institute, 1000 Ljubljana, Slovenia
| | - Julien Vermot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France .,Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France
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11
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Hirashima S, Ohta K, Kanazawa T, Okayama S, Togo A, Miyazono Y, Kusukawa J, Nakamura KI. Three-dimensional ultrastructural analysis and histomorphometry of collagen bundles in the periodontal ligament using focused ion beam/scanning electron microscope tomography. J Periodontal Res 2018; 55:23-31. [PMID: 30035304 DOI: 10.1111/jre.12592] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 06/07/2018] [Accepted: 06/13/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND OBJECTIVE The periodontal ligament (PDL) is an essential tissue for tooth function. However, the 3-dimensional ultrastructure of these PDL collagen bundles on a mesoscale is not clear. We investigated the 3-dimensional ultrastructure of these collagen bundles and quantitatively analyzed their histomorphometry using focused ion beam/scanning electron microscope (FIB/SEM) tomography. MATERIAL AND METHODS The PDLs of the first mandibular molar of male C57BL/6 mice were analyzed using FIB/SEM tomography. The serial images of the collagen bundles so obtained were reconstructed. The collagen bundles were analyzed quantitatively using 3-dimensional histomorphometry. RESULTS Collagen bundles of the PDL demonstrated multiple branched structures, rather than a single rope-like structure, and were wrapped in cytoplasm sheets. The structure of the horizontal fiber of the collagen bundle was an extensive meshwork. In contrast, the oblique and apical fibers of the collagen bundle showed a chain-like structure. The area and the minor and major axis lengths of cross-sections of the horizontal fiber, as determined from 3-dimensional images, were significantly different from those of the oblique and apical fibers. CONCLUSION These findings indicate that collagen bundles in horizontal fiber areas have high strength and that the tooth is firmly anchored to the alveolar bone by the horizontal fibers, but is not secured evenly to the alveolar bone. The tooth is firmly anchored around the cervical area, creating a "slingshot-like structure." This study has provided further insights into the structure of the PDL and forms the basis for the development of more effective therapies for periodontal tissue regeneration.
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Affiliation(s)
- Shingo Hirashima
- Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Japan.,Dental and Oral Medical Center, Kurume University School of Medicine, Kurume, Japan
| | - Keisuke Ohta
- Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Japan.,Advanced Imaging Research Center, Kurume University School of Medicine, Kurume, Japan
| | - Tomonoshin Kanazawa
- Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Japan
| | - Satoko Okayama
- Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Japan
| | - Akinobu Togo
- Advanced Imaging Research Center, Kurume University School of Medicine, Kurume, Japan
| | - Yoshihiro Miyazono
- Dental and Oral Medical Center, Kurume University School of Medicine, Kurume, Japan
| | - Jingo Kusukawa
- Dental and Oral Medical Center, Kurume University School of Medicine, Kurume, Japan
| | - Kei-Ichiro Nakamura
- Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Japan
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12
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Mechanical loading induces primary cilia disassembly in tendon cells via TGFβ and HDAC6. Sci Rep 2018; 8:11107. [PMID: 30038235 PMCID: PMC6056413 DOI: 10.1038/s41598-018-29502-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 07/04/2018] [Indexed: 11/24/2022] Open
Abstract
This study used isolated human tenocytes to test the hypothesis that cyclic mechanical strain directly stimulates primary cilia disassembly, and to elucidate the mechanisms involved. Cells were seeded onto flexible membranes and strained at 0–3%; 1 Hz, for up to 24 hours. Cilia length and prevalence progressively reduced with increasing strain duration but showed full recovery within 2 hours of strain removal. The response to loading was not influenced by actin organisation as seen in other cell types. However, the loading response could be recreated by treatment with TGFβ. Furthermore, treatment with the HDAC6 inhibitor Tubacin, or a TGFβ receptor inhibitor both prevented strain induced cilia disassembly. These data are the first to describe primary cilia expression in isolated tenocytes, showing that mechanical strain regulates cilia expression independent of changes in tendon extracellular matrix. Furthermore, we show that cilia disassembly is mediated by the activation of TGFβ receptors leading to activation of HDAC6. Previous studies have shown that cilia are required for TGFβ signalling and that tendon mechanosignalling is mediated by TGFβ. The present study therefore suggests a novel feedback mechanism whereby cilia disassembly inhibits prolonged TGFβ activation in response to continuous cyclic loading.
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13
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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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14
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Arvind V, Huang AH. Mechanobiology of limb musculoskeletal development. Ann N Y Acad Sci 2017; 1409:18-32. [PMID: 28833194 DOI: 10.1111/nyas.13427] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 05/30/2017] [Accepted: 06/07/2017] [Indexed: 12/26/2022]
Abstract
While there has been considerable progress in identifying molecular regulators of musculoskeletal development, the role of physical forces in regulating induction, differentiation, and patterning events is less well understood. Here, we highlight recent findings in this area, focusing primarily on model systems that test the mechanical regulation of skeletal and tendon development in the limb. We also discuss a few of the key signaling pathways and mechanisms that have been implicated in mechanotransduction and highlight current gaps in knowledge and opportunities for further research in the field.
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Affiliation(s)
- Varun Arvind
- Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Alice H Huang
- Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York
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15
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Rowson D, Knight MM, Screen HR. Zonal variation in primary cilia elongation correlates with localized biomechanical degradation in stress deprived tendon. J Orthop Res 2016; 34:2146-2153. [PMID: 26969839 PMCID: PMC5216897 DOI: 10.1002/jor.23229] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 03/06/2016] [Indexed: 02/04/2023]
Abstract
Tenocytes express primary cilia, which elongate when tendon is maintained in the absence of biomechanical load. Previous work indicates differences in the morphology and metabolism of the tenocytes in the tendon fascicular matrix (FM) and the inter-fascicular matrix (IFM). This study tests the hypothesis that primary cilia in these two regions respond differently to stress deprivation and that this is associated with differences in the biomechanical degradation of the extracellular matrix. Rat tail tendon fascicles were examined over a 7-day period of either stress deprivation or static load. Seven days of stress deprivation induced cilia elongation in both regions. However, elongation was greater in the IFM compared to the FM. Stress deprivation also induced a loss of biomechanical integrity, primarily in the IFM. Static loading reduced both the biomechanical degradation and cilia elongation. The different responses to stress deprivation in the two tendon regions are likely to be important for the aetiology of tendinopathy. Furthermore, these data suggest that primary cilia elongate in response to biomechanical degradation rather than simply the removal of load. This response to degradation is likely to have important consequences for cilia signalling in tendon and as well as in other connective tissues. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 34:2146-2153, 2016.
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Affiliation(s)
- Daniel Rowson
- Institute of Bioengineering and School of Engineering and Materials ScienceQueen Mary University of LondonMile End RoadLondonE1 4NSUnited Kingdom
| | - Martin M. Knight
- Institute of Bioengineering and School of Engineering and Materials ScienceQueen Mary University of LondonMile End RoadLondonE1 4NSUnited Kingdom
| | - Hazel R.C. Screen
- Institute of Bioengineering and School of Engineering and Materials ScienceQueen Mary University of LondonMile End RoadLondonE1 4NSUnited Kingdom
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Zhang Q, Ge H, Jiang Y, Cheng B, Zhou D, Xu N. Microarray profiling analysis of long non-coding RNAs expression in tendinopathy: identification for potential biomarkers and mechanisms. Int J Exp Pathol 2016; 96:387-94. [PMID: 26764085 DOI: 10.1111/iep.12158] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 10/15/2015] [Indexed: 01/21/2023] Open
Abstract
The role of lncRNAs in pathologies of tendinopathy has not been researched so far, this study aims to identify the role and potent mechanism of lncRNAs in tendinopathy with a bioinformatic analysis. The gene profile of GSE26051 based on the platform of Affymetrix Human Genome U133B Array condensed was downloaded from Gene Expression Omnibus. A total of 46 specimens (including 23 normal samples and 23 tendinopathy specimens) were available. Compared with the control samples, differentially expressed genes (DEGs) of tendinopathy was identified the by packages in R. The selected DEGs were further analysed using bioinformatics methods including co-expression and enrichment analysis to detect the potential role of lncRNAs. A total of 40 different expressed lncRNAs were identified. However, most of the identified lncRNAs have not been researched before. And this study only annotate one of the identified lncRNAs successfully, the LOC100507027 (myoregulin), with the potential role in regulating skeletal muscle tissue development and skeletal muscle organ development.
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Affiliation(s)
- Qiang Zhang
- Department of Orthopaedics, Changzhou No.2 people's hospital, Changzhou, Jiangsu, China
| | - Heng'an Ge
- Department of Orthopedics, Affiliated Shanghai Tenth People's Hospital of Tongji University, Shanghai, People's Republic of China.,Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Yuqing Jiang
- Department of Orthopaedics, Changzhou No.2 people's hospital, Changzhou, Jiangsu, China
| | - Biao Cheng
- Department of Orthopedics, Affiliated Shanghai Tenth People's Hospital of Tongji University, Shanghai, People's Republic of China.,Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Dong Zhou
- Department of Orthopaedics, Changzhou No.2 people's hospital, Changzhou, Jiangsu, China
| | - Nanwei Xu
- Department of Orthopaedics, Changzhou No.2 people's hospital, Changzhou, Jiangsu, China
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Cell Signaling in Tenocytes: Response to Load and Ligands in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 920:79-95. [DOI: 10.1007/978-3-319-33943-6_7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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18
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Lavagnino M, Wall ME, Little D, Banes AJ, Guilak F, Arnoczky SP. Tendon mechanobiology: Current knowledge and future research opportunities. J Orthop Res 2015; 33:813-22. [PMID: 25763779 PMCID: PMC4524513 DOI: 10.1002/jor.22871] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 02/13/2015] [Indexed: 02/04/2023]
Abstract
Tendons mainly function as load-bearing tissues in the muscloskeletal system; transmitting loads from muscle to bone. Tendons are dynamic structures that respond to the magnitude, direction, frequency, and duration of physiologic as well as pathologic mechanical loads via complex interactions between cellular pathways and the highly specialized extracellular matrix. This paper reviews the evolution and current knowledge of mechanobiology in tendon development, homeostasis, disease, and repair. In addition, we review several novel mechanotransduction pathways that have been identified recently in other tissues and cell types, providing potential research opportunities in the field of tendon mechanobiology. We also highlight current methods, models, and technologies being used in a wide variety of mechanobiology research that could be investigated in the context of their potential applicability for answering some of the fundamental unanswered questions in this field. The article concludes with a review of the major questions and future goals discussed during the recent ORS/ISMMS New Frontiers in Tendon Research Conference held on September 10 and 11, 2014 in New York City.
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Affiliation(s)
- Michael Lavagnino
- Laboratory for Comparative Orthopaedic Research, College of Veterinary Medicine Michigan State University, East Lansing, Michigan
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19
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Surface topography regulates wnt signaling through control of primary cilia structure in mesenchymal stem cells. Sci Rep 2013; 3:3545. [PMID: 24346024 PMCID: PMC3866595 DOI: 10.1038/srep03545] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 12/03/2013] [Indexed: 12/22/2022] Open
Abstract
The primary cilium regulates cellular signalling including influencing wnt sensitivity by sequestering β-catenin within the ciliary compartment. Topographic regulation of intracellular actin-myosin tension can control stem cell fate of which wnt is an important mediator. We hypothesized that topography influences mesenchymal stem cell (MSC) wnt signaling through the regulation of primary cilia structure and function. MSCs cultured on grooves expressed elongated primary cilia, through reduced actin organization. siRNA inhibition of anterograde intraflagellar transport (IFT88) reduced cilia length and increased active nuclear β-catenin. Conversely, increased primary cilia assembly in MSCs cultured on the grooves was associated with decreased levels of nuclear active β-catenin, axin-2 induction and proliferation, in response to wnt3a. This negative regulation, on grooved topography, was reversed by siRNA to IFT88. This indicates that subtle regulation of IFT and associated cilia structure, tunes the wnt response controlling stem cell differentiation.
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Abstract
Cilia and flagella are surface-exposed, finger-like organelles whose core consists of a microtubule (MT)-based axoneme that grows from a modified centriole, the basal body. Cilia are found on the surface of many eukaryotic cells and play important roles in cell motility and in coordinating a variety of signaling pathways during growth, development, and tissue homeostasis. Defective cilia have been linked to a number of developmental disorders and diseases, collectively called ciliopathies. Cilia are dynamic organelles that assemble and disassemble in tight coordination with the cell cycle. In most cells, cilia are assembled during growth arrest in a multistep process involving interaction of vesicles with appendages present on the distal end of mature centrioles, and addition of tubulin and other building blocks to the distal tip of the basal body and growing axoneme; these building blocks are sorted through a region at the cilium base known as the ciliary necklace, and then transported via intraflagellar transport (IFT) along the axoneme toward the tip for assembly. After assembly, the cilium frequently continues to turn over and incorporate tubulin at its distal end in an IFT-dependent manner. Prior to cell division, the cilia are usually resorbed to liberate centrosomes for mitotic spindle pole formation. Here, we present an overview of the main cytoskeletal structures associated with cilia and centrioles with emphasis on the MT-associated appendages, fibers, and filaments at the cilium base and tip. The composition and possible functions of these structures are discussed in relation to cilia assembly, disassembly, and length regulation.
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Affiliation(s)
- Lotte B Pedersen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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21
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Delaine-Smith RM, Sittichokechaiwut A, Reilly GC. Primary cilia respond to fluid shear stress and mediate flow-induced calcium deposition in osteoblasts. FASEB J 2013; 28:430-9. [PMID: 24097311 PMCID: PMC4012163 DOI: 10.1096/fj.13-231894] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Bone turnover in vivo is regulated by mechanical forces such as shear stress originating from interstitial oscillatory fluid flow (OFF), and bone cells in vitro respond to mechanical loading. However, the mechanisms by which bone cells sense mechanical forces, resulting in increased mineral deposition, are not well understood. The aim of this study was to investigate the role of the primary cilium in mechanosensing by osteoblasts. MLO-A5 murine osteoblasts were cultured in monolayer and subjected to two different OFF regimens: 5 short (2 h daily) bouts of OFF followed by morphological analysis of primary cilia; or exposure to chloral hydrate to damage or remove primary cilia and 2 short bouts (2 h on consecutive days) of OFF. Primary cilia were shorter and there were fewer cilia per cell after exposure to periods of OFF compared with static controls. Damage or removal of primary cilia inhibited OFF-induced PGE2 release into the medium and mineral deposition, assayed by Alizarin red staining. We conclude that primary cilia are important mediators of OFF-induced mineral deposition, which has relevance for the design of bone tissue engineering strategies and may inform clinical treatments of bone disorders causes by load-deficiency.—Delaine-Smith, R. M., Sittichokechaiwut, A., Reilly, G. C. Primary cilia respond to fluid shear stress and mediate flow-induced calcium deposition in osteoblasts.
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Affiliation(s)
- Robin M Delaine-Smith
- 1School of Engineering and Materials Science, Queen Mary University of London, Mile End Rd., London, E1 4NS, UK.
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Lavagnino M, Gardner K, Sedlak AM, Arnoczky SP. Tendon cell ciliary length as a biomarker of in situ cytoskeletal tensional homeostasis. Muscles Ligaments Tendons J 2013; 3:118-121. [PMID: 24367770 PMCID: PMC3838319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
To determine if tendon cell ciliary length could be used as a biomarker of cytoskeletal tensional homeostasis, 20 mm long adult rat tail tendons were placed in double artery clamps set 18 mm apart to create a 10% laxity. The tendons were allowed to contract over a 7 day period under culture conditions. At 0, 1, 5, and 7 days the tendon cell cilia were stained and ciliary length measured using confocal imaging. There was a significant (p<0.001) increase in ciliary length at 1 day. At day 5 (when the tendon became visibly taut) there was a significant (p<0.001) decrease in ciliary length compared to day 1. By day 7 the tendon remained taut and ciliary length returned to day zero values (p=0.883). These results suggest that cilia length reflects the local mechanobiological environment of tendon cells and could be used as a potential in situ biomarker of altered cytoskeletal tensional homeostasis.
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Affiliation(s)
| | | | | | - Steven Paul Arnoczky
- Corresponding author: Steven Paul Arnoczky, Laboratory for Comparative Orthopaedic Research, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan 48824, USA, E-mail:
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Abstract
The centrosome, a major organizer of microtubules, has important functions in regulating cell shape, polarity, cilia formation and intracellular transport as well as the position of cellular structures, including the mitotic spindle. By means of these activities, centrosomes have important roles during animal development by regulating polarized cell behaviors, such as cell migration or neurite outgrowth, as well as mitotic spindle orientation. In recent years, the pace of discovery regarding the structure and composition of centrosomes has continuously accelerated. At the same time, functional studies have revealed the importance of centrosomes in controlling both morphogenesis and cell fate decision during tissue and organ development. Here, we review examples of centrosome and centriole positioning with a particular emphasis on vertebrate developmental systems, and discuss the roles of centrosome positioning, the cues that determine positioning and the mechanisms by which centrosomes respond to these cues. The studies reviewed here suggest that centrosome functions extend to the development of tissues and organs in vertebrates.
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Affiliation(s)
- Nan Tang
- Department of Anatomy, Cardiovascular Research Institute, The University of California, San Francisco, USA.
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Docking S, Samiric T, Scase E, Purdam C, Cook J. Relationship between compressive loading and ECM changes in tendons. Muscles Ligaments Tendons J 2013; 3:7-11. [PMID: 23885340 DOI: 10.11138/mltj/2013.3.1.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Tendons are designed to absorb and transfer large amounts of tensile load. The well organised, strong yet flexible, extracellular matrix allows for this function. Many tendons are also subject to compressive loads, such as at the entheses, as the tendon wraps around bony protuberances or from internal compression during tensile loading or twisting. Tendinopathy, the clinical syndrome of pain and dysfunction in a tendon is usually the result of overload. However, it is not only the tensile overload that should be considered, as it has been shown that compressive loads change tendon structure and that combination loads can induce tendon pathology. This review summarises how load is detected by the tenocytes, how they respond to compressive load and the resulting extracellular matrix changes that occur. Understanding the effect of compression on tendon structure and function may provide directions for future matrix based interventions.
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Affiliation(s)
- Sean Docking
- School of Primary Health Care, Monash University, Peninsula Campus, Frankston, Australia
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Seeger-Nukpezah T, Golemis EA. The extracellular matrix and ciliary signaling. Curr Opin Cell Biol 2012; 24:652-61. [PMID: 22819513 DOI: 10.1016/j.ceb.2012.06.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 05/29/2012] [Accepted: 06/11/2012] [Indexed: 12/24/2022]
Abstract
The primary cilium protrudes like an antenna from the cell surface, sensing mechanical and chemical cues provided in the cellular environment. In some tissue types, ciliary orientation to lumens allows response to fluid flow; in others, such as bone, ciliary protrusion into the extracellular matrix allows response to compression forces. The ciliary membrane contains receptors for Hedgehog, Wnt, Notch, and other potent growth factors, and in some instances also harbors integrin and cadherin family members, allowing receipt of a robust range of signals. A growing list of ciliopathies, arising from deficient formation or function of cilia, includes both developmental defects and chronic, progressive disorders such as polycystic kidney disease (PKD); changes in ciliary function have been proposed to support cancer progression. Recent findings have revealed extensive signaling dialog between cilia and extracellular matrix (ECM), with defects in cilia associated with fibrosis in multiple contexts. Further, a growing number of proteins have been determined to possess multiple roles in control of cilia and focal adhesion interactions with the ECM, further coordinating functionality. We summarize and discuss these recent findings.
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Affiliation(s)
- Tamina Seeger-Nukpezah
- Program in Developmental Therapeutics, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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26
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Saggese T, Young AA, Huang C, Braeckmans K, McGlashan SR. Development of a method for the measurement of primary cilia length in 3D. Cilia 2012; 1:11. [PMID: 23351171 PMCID: PMC3555708 DOI: 10.1186/2046-2530-1-11] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 07/03/2012] [Indexed: 01/01/2023] Open
Abstract
Background Primary cilia length is an important measure of cell and tissue function. While accurate length measurements can be calculated from cells in 2D culture, measurements in tissue or 3D culture are inherently difficult due to optical distortions. This study uses a novel combination of image processing techniques to rectify optical distortions and accurately measure cilia length from 3D images. Methods Point spread functions and experimental resolutions were calculated from subresolution microspheres embedded in 3D agarose gels for both wide-field fluorescence and confocal laser scanning microscopes. The degree of axial smearing and spherical aberration was calculated from xy:xz diameter ratios of 3D image data sets of 4 μm microspheres that had undergone deconvolution and/or Gaussian blurring. Custom-made 18 and 50 μm fluorescent microfibers were also used as calibration objects to test the suitability of processed image sets for 3D skeletonization. Microfiber length in 2D was first measured to establish an original population mean. Fibers were then embedded in 3D agarose gels to act as ciliary models. 3D image sets of microfibers underwent deconvolution and Gaussian blurring. Length measurements within 1 standard deviation of the original 2D population mean were deemed accurate. Finally, the combined method of deconvolution, Gaussian blurring and skeletonization was compared to previously published methods using images of immunofluorescently labeled renal and chondrocyte primary cilia. Results Deconvolution significantly improved contrast and resolution but did not restore the xy:xz diameter ratio (0.80). Only the additional step of Gaussian blurring equalized xy and xz resolutions and yielded a diameter ratio of 1.02. Following image processing, skeletonization successfully estimated microfiber boundaries and allowed reliable and repeatable measurement of fiber lengths in 3D. We also found that the previously published method of calculating length from 2D maximum projection images significantly underestimated ciliary length. Conclusions This study used commercial and public domain image processing software to rectify a long-standing problem of 3D microscopy. We have shown that a combination of deconvolution and Gaussian blurring rectifies optical distortions inherent in 3D images and allows accurate skeletonization and length measurement of microfibers and primary cilia that are bent or curved in 3D space.
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Affiliation(s)
- Taryn Saggese
- Department of Anatomy with Radiology, Private Bag 92019, University of Auckland, Auckland 1023, New Zealand.
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Hoey DA, Chen JC, Jacobs CR. The primary cilium as a novel extracellular sensor in bone. Front Endocrinol (Lausanne) 2012; 3:75. [PMID: 22707948 PMCID: PMC3374377 DOI: 10.3389/fendo.2012.00075] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 05/21/2012] [Indexed: 11/18/2022] Open
Abstract
Mechanically induced adaptation of bone is required to maintain a healthy skeleton and defects in this process can lead to dramatic changes in bone mass, resulting in bone diseases such as osteoporosis. Therefore, understanding how this process occurs could yield novel therapeutics to treat diseases of excessive bone loss or formation. Over the past decade the primary cilium has emerged as a novel extracellular sensor in bone, being required to transduce changes in the extracellular mechanical environment into biochemical responses regulating bone adaptation. In this review, we introduce the primary cilium as a novel extracellular sensor in bone; discuss the in vitro and in vivo findings of primary cilia based sensing in bone; explore the role of the primary cilium in regulating stem cell osteogenic fate commitment and finish with future directions of research and possible development of cilia targeting therapeutics to treat bone diseases.
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Affiliation(s)
- David A. Hoey
- Department of Biomedical Engineering, Columbia University in the City of New YorkNew York, NY, USA
- Department of Anatomy, Royal College of Surgeons in IrelandDublin, Ireland
- Department of Mechanical, Aeronautical and Biomedical Engineering, Centre for Applied Biomedical Engineering Research, Materials and Surface Science Institute, University of LimerickLimerick, Ireland
- *Correspondence: David A. Hoey, Department of Mechanical, Aeronautical and Biomedical Engineering, Centre for Applied Biomedical Engineering Research, Materials and Surface Science Institute, University of Limerick, Limerick, Ireland. e-mail:
| | - Julia C. Chen
- Department of Biomedical Engineering, Columbia University in the City of New YorkNew York, NY, USA
| | - Christopher R. Jacobs
- Department of Biomedical Engineering, Columbia University in the City of New YorkNew York, NY, USA
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Jones TJ, Adapala RK, Geldenhuys WJ, Bursley C, AbouAlaiwi WA, Nauli SM, Thodeti CK. Primary cilia regulates the directional migration and barrier integrity of endothelial cells through the modulation of hsp27 dependent actin cytoskeletal organization. J Cell Physiol 2011; 227:70-6. [PMID: 21837772 DOI: 10.1002/jcp.22704] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cilia are mechanosensing organelles that communicate extracellular signals into intracellular responses. Altered functions of primary cilia play a key role in the development of various diseases including polycystic kidney disease. Here, we show that endothelial cells from the oak ridge polycystic kidney (Tg737(orpk/orpk) ) mouse, with impaired cilia assembly, exhibit a reduction in the actin stress fibers and focal adhesions compared to wild-type (WT). In contrast, endothelial cells from polycystin-1 deficient mice (pkd1(null/null) ), with impaired cilia function, display robust stress fibers, and focal adhesion assembly. We found that the Tg737(orpk/orpk) cells exhibit impaired directional migration and endothelial cell monolayer permeability compared to the WT and pkd1(null/null) cells. Finally, we found that the expression of heat shock protein 27 (hsp27) and the phosphorylation of focal adhesion kinase (FAK) are downregulated in the Tg737(orpk/orpk) cells and overexpression of hsp27 restored both FAK phosphorylation and cell migration. Taken together, these results demonstrate that disruption of the primary cilia structure or function compromises the endothelium through the suppression of hsp27 dependent actin organization and focal adhesion formation, which may contribute to the vascular dysfunction in ciliopathies.
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Affiliation(s)
- Thomas J Jones
- Department of Pharmaceutical Sciences, Northeastern Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio 44272, USA
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Farnum CE, Wilsman NJ. Axonemal positioning and orientation in three-dimensional space for primary cilia: what is known, what is assumed, and what needs clarification. Dev Dyn 2011; 240:2405-31. [PMID: 22012592 PMCID: PMC3278774 DOI: 10.1002/dvdy.22756] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Two positional characteristics of the ciliary axoneme--its location on the plasma membrane as it emerges from the cell, and its orientation in three-dimensional (3D) space--are known to be critical for optimal function of actively motile cilia (including nodal cilia), as well as for modified cilia associated with special senses. However, these positional characteristics have not been analyzed to any significant extent for primary cilia. This review briefly summarizes the history of knowledge of these two positional characteristics across a wide spectrum of cilia, emphasizing their importance for proper function. Then the review focuses what is known about these same positional characteristics for primary cilia in all major tissue types where they have been reported. The review emphasizes major areas that would be productive for future research for understanding how positioning and 3D orientation of primary cilia may be related to their hypothesized signaling roles within different cellular populations.
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Affiliation(s)
- Cornelia E Farnum
- Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853, USA.
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Farnum CE, Williams RM, Donnelly E. Analyzing primary cilia by multiphoton microscopy. Methods Cell Biol 2009; 94:117-35. [PMID: 20362088 DOI: 10.1016/s0091-679x(08)94006-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In this chapter, a technique is outlined for the use of immunohistochemistry (IHC) followed by multiphoton microscopy (MPM) for the analysis of incidence, length, and 3D orientation of the axoneme of the primary cilium. Although the application presented specifically emphasizes localizations in tenocytes and chondrocytes, the technique is applicable to cells in a wide range of connective tissues. The primary advantages of utilizing MPM as opposed to TEM for these kinds of ciliary analyses are the rapidity of the technique for preparation of the samples and the ability to collect data from multiple cells simultaneously. Using MPM, the axoneme, basal body, and associated centriole can be visualized by specific IHC with localizing antibodies. However, the resolution achieved through TEM analyses allows the complex morphology of the primary cilium to be visualized, and this remains the primary advantage of TEM versus MPM. SHG, which occurs only with MPM, allows visualization of collagen fibrils and is particularly advantageous for localizing primary cilia associated with cells in connective tissues. This, and the deep penetration with less photobleaching, are the primary advantages of MPM compared to confocal microscopy. As with any microscopical technique, the protocol needs to be optimized for any given tissue. In particular, additional antigen retrieval techniques to enhance the unmasking of specific epitopes for antibody binding may be required for adaptation of this approach to other dense connective tissues with complex spatial organizations such as intervertebral disc or meniscus.
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Affiliation(s)
- Cornelia E Farnum
- Department of Biomedical Sciences, Cornell University, Ithaca, New York 14865, USA
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