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Hecht JT, Veerisetty AC, Hossain MG, Chiu F, Posey KL. CurQ+, a Next-Generation Formulation of Curcumin, Ameliorates Growth Plate Chondrocyte Stress and Increases Limb Growth in a Mouse Model of Pseudoachondroplasia. Int J Mol Sci 2023; 24:ijms24043845. [PMID: 36835255 PMCID: PMC9959842 DOI: 10.3390/ijms24043845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 01/18/2023] [Accepted: 02/03/2023] [Indexed: 02/17/2023] Open
Abstract
Mutations in cartilage oligomeric matrix protein (COMP) causes protein misfolding and accumulation in chondrocytes that compromises skeletal growth and joint health in pseudoachondroplasia (PSACH), a severe dwarfing condition. Using the MT-COMP mice, a murine model of PSACH, we showed that pathological autophagy blockage was key to the intracellular accumulation of mutant-COMP. Autophagy is blocked by elevated mTORC1 signaling, preventing ER clearance and ensuring chondrocyte death. We demonstrated that resveratrol reduces the growth plate pathology by relieving the autophagy blockage allowing the ER clearance of mutant-COMP, which partially rescues limb length. To expand potential PSACH treatment options, CurQ+, a uniquely absorbable formulation of curcumin, was tested in MT-COMP mice at doses of 82.3 (1X) and 164.6 mg/kg (2X). CurQ+ treatment of MT-COMP mice from 1 to 4 weeks postnatally decreased mutant COMP intracellular retention, inflammation, restoring both autophagy and chondrocyte proliferation. CurQ+ reduction of cellular stress in growth plate chondrocytes dramatically reduced chondrocyte death, normalized femur length at 2X 164.6 mg/kg and recovered 60% of lost limb growth at 1X 82.3 mg/kg. These results indicate that CurQ+ is a potential therapy for COMPopathy-associated lost limb growth, joint degeneration, and other conditions involving persistent inflammation, oxidative stress, and a block of autophagy.
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Affiliation(s)
- Jacqueline T. Hecht
- Department of Pediatrics, McGovern Medical School at UTHealth Houston, Houston, TX 77030, USA
- School of Dentistry, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA
| | - Alka C. Veerisetty
- Department of Pediatrics, McGovern Medical School at UTHealth Houston, Houston, TX 77030, USA
| | - Mohammad G. Hossain
- Department of Pediatrics, McGovern Medical School at UTHealth Houston, Houston, TX 77030, USA
| | - Frankie Chiu
- Department of Pediatrics, McGovern Medical School at UTHealth Houston, Houston, TX 77030, USA
| | - Karen L. Posey
- Department of Pediatrics, McGovern Medical School at UTHealth Houston, Houston, TX 77030, USA
- Correspondence:
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Forte-Gomez HF, Gioia R, Tonelli F, Kobbe B, Koch P, Bloch W, Paulsson M, Zaucke F, Forlino A, Wagener R. Structure, evolution and expression of zebrafish cartilage oligomeric matrix protein (COMP, TSP5). CRISPR-Cas mutants show a dominant phenotype in myosepta. Front Endocrinol (Lausanne) 2022; 13:1000662. [PMID: 36452329 PMCID: PMC9702538 DOI: 10.3389/fendo.2022.1000662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 10/07/2022] [Indexed: 11/16/2022] Open
Abstract
COMP (Cartilage Oligomeric Matrix Protein), also named thrombospondin-5, is a member of the thrombospondin family of extracellular matrix proteins. It is of clinical relevance, as in humans mutations in COMP lead to chondrodysplasias. The gene encoding zebrafish Comp is located on chromosome 11 in synteny with its mammalian orthologs. Zebrafish Comp has a domain structure identical to that of tetrapod COMP and shares 74% sequence similarity with murine COMP. Zebrafish comp is expressed from 5 hours post fertilization (hpf) on, while the protein is first detectable in somites of 11 hpf embryos. During development and in adults comp is strongly expressed in myosepta, craniofacial tendon and ligaments, around ribs and vertebra, but not in its name-giving tissue cartilage. As in mammals, zebrafish Comp forms pentamers. It is easily extracted from 5 days post fertilization (dpf) whole zebrafish. The lack of Comp expression in zebrafish cartilage implies that its cartilage function evolved recently in tetrapods. The expression in tendon and myosepta may indicate a more fundamental function, as in evolutionary distant Drosophila muscle-specific adhesion to tendon cells requires thrombospondin. A sequence encoding a calcium binding motif within the first TSP type-3 repeat of zebrafish Comp was targeted by CRISPR-Cas. The heterozygous and homozygous mutant Comp zebrafish displayed a patchy irregular Comp staining in 3 dpf myosepta, indicating a dominant phenotype. Electron microscopy revealed that the endoplasmic reticulum of myosepta fibroblasts is not affected in homozygous fish. The disorganized extracellular matrix may indicate that this mutation rather interferes with extracellular matrix assembly, similar to what is seen in a subgroup of chondrodysplasia patients. The early expression and easy detection of mutant Comp in zebrafish points to the potential of using the zebrafish model for large scale screening of small molecules that can improve secretion or function of disease-associated COMP mutants.
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Affiliation(s)
| | - Roberta Gioia
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy
| | - Francesca Tonelli
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy
| | - Birgit Kobbe
- Center for Biochemistry, University of Cologne, Cologne, Germany
| | - Peter Koch
- Department of Pharmacology, University Clinic Cologne, Cologne, Germany
| | - Wilhelm Bloch
- Institute of Cardiovascular Research and Sport Medicine, German Sport University, Cologne, Germany
| | - Mats Paulsson
- Center for Biochemistry, Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | - Frank Zaucke
- Dr. Rolf M. Schwiete Research Unit for Osteoarthritis, Department of Orthopedics (Friedrichsheim), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Antonella Forlino
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy
| | - Raimund Wagener
- Center for Biochemistry, Center for Molecular Medicine, University of Cologne, Cologne, Germany
- *Correspondence: Raimund Wagener,
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Carminati L, Taraboletti G. Thrombospondins in bone remodeling and metastatic bone disease. Am J Physiol Cell Physiol 2020; 319:C980-C990. [PMID: 32936697 DOI: 10.1152/ajpcell.00383.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Thrombospondins (TSPs) are a family of five multimeric matricellular proteins. Through a wide range of interactions, TSPs play pleiotropic roles in embryogenesis and in tissue remodeling in adult physiology as well as in pathological conditions, including cancer development and metastasis. TSPs are active in bone remodeling, the process of bone resorption (osteolysis) and deposition (osteogenesis) that maintains bone homeostasis. TSPs are particularly involved in aberrant bone remodeling, including osteolytic and osteoblastic skeletal cancer metastasis, frequent in advanced cancers such as breast and prostate carcinoma. TSPs are major players in the bone metastasis microenvironment, where they finely tune the cross talk between tumor cells and bone resident cells in the metastatic niche. Each TSP family member has different effects on the differentiation and activity of bone cells-including the bone-degrading osteoclasts and the bone-forming osteoblasts-with different outcomes on the development and growth of osteolytic and osteoblastic metastases. Here, we overview the involvement of TSP family members in the bone tissue microenvironment, focusing on their activity on osteoclasts and osteoblasts in bone remodeling, and present the evidence to date of their roles in bone metastasis establishment and growth.
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Affiliation(s)
- Laura Carminati
- Laboratory of Tumor Microenvironment, Department of Oncology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Giulia Taraboletti
- Laboratory of Tumor Microenvironment, Department of Oncology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
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Burger A, Roosenboom J, Hossain M, Weinberg SM, Hecht JT, Posey KL. Mutant COMP shapes growth and development of skull and facial structures in mice and humans. Mol Genet Genomic Med 2020; 8:e1251. [PMID: 32347019 PMCID: PMC7336729 DOI: 10.1002/mgg3.1251] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 03/13/2020] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Cartilage oligomeric matrix protein (COMP) is an important extracellular matrix protein primarily functioning in the musculoskeletal tissues and especially endochondral bone growth. Mutations in COMP cause the skeletal dysplasia pseudoachondroplasia (PSACH) that is characterized by short limbs and fingers, joint laxity, and abnormalities but a striking lack of skull and facial abnormalities. METHODS This study examined both mice and humans to determine how mutant-COMP affects face and skull growth. RESULTS Mutant COMP (MT-COMP) mice were phenotypically distinct. Snout length and skull height were diminished in MT-COMP mouse and the face more closely resembled younger controls. Three-dimensional facial measurements of PSACH faces showed widely spaced eyes, reduced lower facial height, and decreased nasal protrusion, which correlated with a more juvenile appearing face. Neither MT-COMP mice nor PSACH individuals show midface hypoplasia usually associated with abnormal endochondral bone growth. MT-COMP mice do show delayed endochondral and membranous skull ossification that normalizes with age. CONCLUSION Therefore, mutant-COMP affects both endochondral and intramembranous bones of the skull resulting in a reduction of the nose and lower facial height in mice and humans, in addition to its well-defined role in the growth plate chondrocytes.
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Affiliation(s)
- Alexander Burger
- Center for Craniofacial ResearchUTHealth School of DentistryHoustonTXUSA
| | | | - Mohammad Hossain
- Department of PediatricsMcGovern Medical SchoolThe University of Texas Health Science Center at Houston (UTHealth)HoustonTXUSA
| | - Seth M. Weinberg
- Department of Oral BiologyUniversity of PittsburghPittsburghPAUSA
- Department of Human GeneticsUniversity of PittsburghPittsburghPAUSA
- Department of AnthropologyUniversity of PittsburghPittsburghPAUSA
| | - Jacqueline T. Hecht
- Center for Craniofacial ResearchUTHealth School of DentistryHoustonTXUSA
- Department of PediatricsMcGovern Medical SchoolThe University of Texas Health Science Center at Houston (UTHealth)HoustonTXUSA
| | - Karen L. Posey
- Department of PediatricsMcGovern Medical SchoolThe University of Texas Health Science Center at Houston (UTHealth)HoustonTXUSA
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Posey KL, Coustry F, Veerisetty AC, Hossain MG, Gambello MJ, Hecht JT. Novel mTORC1 Mechanism Suggests Therapeutic Targets for COMPopathies. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 189:132-146. [PMID: 30553437 DOI: 10.1016/j.ajpath.2018.09.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/20/2018] [Accepted: 09/17/2018] [Indexed: 02/06/2023]
Abstract
Cartilage oligomeric matrix protein (COMP) is a large, multifunctional extracellular protein that, when mutated, is retained in the rough endoplasmic reticulum (ER). This retention elicits ER stress, inflammation, and oxidative stress, resulting in dysfunction and death of growth plate chondrocytes. While identifying the cellular pathologic mechanisms underlying the murine mutant (MT)-COMP model of pseudoachondroplasia, increased midline-1 (MID1) expression and mammalian target of rapamycin complex 1 (mTORC1) signaling was found. This novel role for MID1/mTORC1 signaling was investigated since treatments shown to repress the pathology also reduced Mid1/mTORC1. Although ER stress-inducing drugs or tumor necrosis factor α (TNFα) in rat chondrosarcoma cells increased Mid1, oxidative stress did not, establishing that ER stress- or TNFα-driven inflammation alone is sufficient to elevate MID1 expression. Since MID1 ubiquitinates protein phosphatase 2A (PP2A), a negative regulator of mTORC1, PP2A was evaluated in MT-COMP growth plate chondrocytes. PP2A was decreased, indicating de-repression of mTORC1 signaling. Rapamycin treatment in MT-COMP mice reduced mTORC1 signaling and intracellular retention of COMP, and increased proliferation, but did not change inflammatory markers IL-16 and eosinophil peroxidase. Lastly, mRNA from tuberous sclerosis-1/2-null mice brain tissue exhibiting ER stress had increased Mid1 expression, confirming the relationship between ER stress and MID1/mTORC1 signaling. These findings suggest a mechanistic link between ER stress and MID1/mTORC1 signaling that has implications extending to other conditions involving ER stress.
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Affiliation(s)
- Karen L Posey
- Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas.
| | - Francoise Coustry
- Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas
| | - Alka C Veerisetty
- Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas
| | - Mohammad G Hossain
- Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas
| | - Michael J Gambello
- Human Genetics and Pediatrics, Emory University School of Medicine, Atlanta, Georgia
| | - Jacqueline T Hecht
- Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas; School of Dentistry, University of Texas Health Science Center, Houston, Texas
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Abstract
PURPOSE In 1959, Maroteaux and Lamy initially designated pseudoachondroplasia as a distinct dysplasia different from achondroplasia the most common form of skeletal dysplasia. Pseudoachondroplasia is caused by a mutation in the collagen oligomeric matrix protein gene (COMP) gene on chromosome 19p13.1-p12 encoding the COMP. The COMP gene mutations result in rendering the articular and growth plate cartilages incapable of withstanding routine biomechanical loads with resultant deformity of the joints. The purpose of the study was to characterize the typical orthopaedic findings in pseudoachondroplasia. METHODS The charts and radiographs of 141 patients with pseudoachondroplasia were analyzed. This cohort, to our knowledge, represents the largest group of patients describing the typical orthopaedic manifestations of pseudoachondroplasia. RESULTS Patients with pseudoachondroplasia have normal craniofacial appearance with normal intelligence. Short stature is not present at birth and generally appears by two to four years of age. The condition is a form of spondyloepiphyseal dysplasia and the long bones are characterized by dysplastic changes in the epiphysis, metaphysis and vertebral bodies. Radiographically the long bones have altered the appearance and structure of the epiphyses with small irregularly formed or fragmented epiphyses or flattening. The metaphyseal regions of the long bones show flaring, widening or 'trumpeting'. The cervical (89%) and thoracic and lumbar vertebrae show either platyspondyly, ovoid, 'cod-fish' deformity or anterior 'beaking'. Kyphosis (28%), scoliosis (58%) and lumbar lordosis (100%) are commonly seen. The femoral head and acetabulum are severely dysplastic (100%). The knees show either genu valgum (22%), genu varum (56%) or 'windswept' deformity (22%). CONCLUSION Most commonly these distortions of the appendicular and the axial skeleton lead to premature arthritis particularly of the hips and often the knees not uncommonly in the 20- to 30-year-old age group. LEVEL OF EVIDENCE III.
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Affiliation(s)
- D. S. Weiner
- Department of Orthopaedics, Akron Children’s Hospital, Akron, Ohio, USA,Correspondence should be sent to D. S. Weiner, Department of Orthopaedics, Akron Children’s Hospital, 300 Locust Street, Ste. 250, Akron, OH 44302-1821, USA.
| | - J. Guirguis
- Department of Orthopaedics, Akron Children’s Hospital, Akron, Ohio, USA
| | - M. Makowski
- Department of Orthopaedics, Cleveland Clinic/Akron General, Akron, Ohio, USA
| | - S. Testa
- Rebecca D. Considine Research Institute/Akron Children’s Hospital, Akron, Ohio, USA
| | - L. Shauver
- Rebecca D. Considine Research Institute/Akron Children’s Hospital, Akron, Ohio, USA
| | - D. Morgan
- Rebecca D. Considine Research Institute/Akron Children’s Hospital, Akron, Ohio, USA
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7
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Lamandé SR, Bateman JF. Genetic Disorders of the Extracellular Matrix. Anat Rec (Hoboken) 2019; 303:1527-1542. [PMID: 30768852 PMCID: PMC7318566 DOI: 10.1002/ar.24086] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 10/26/2018] [Indexed: 12/11/2022]
Abstract
Mutations in the genes for extracellular matrix (ECM) components cause a wide range of genetic connective tissues disorders throughout the body. The elucidation of mutations and their correlation with pathology has been instrumental in understanding the roles of many ECM components. The pathological consequences of ECM protein mutations depend on its tissue distribution, tissue function, and on the nature of the mutation. The prevalent paradigm for the molecular pathology has been that there are two global mechanisms. First, mutations that reduce the production of ECM proteins impair matrix integrity largely due to quantitative ECM defects. Second, mutations altering protein structure may reduce protein secretion but also introduce dominant negative effects in ECM formation, structure and/or stability. Recent studies show that endoplasmic reticulum (ER) stress, caused by mutant misfolded ECM proteins, makes a significant contribution to the pathophysiology. This suggests that targeting ER‐stress may offer a new therapeutic strategy in a range of ECM disorders caused by protein misfolding mutations. Anat Rec, 2019. © 2019 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.
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Affiliation(s)
- Shireen R Lamandé
- Musculoskeletal Research, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville Victoria, Australia.,Department of Paediatrics, University of Melbourne, Parkville Victoria, Australia
| | - John F Bateman
- Musculoskeletal Research, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville Victoria, Australia.,Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville Victoria, Australia
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8
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Posey KL, Coustry F, Hecht JT. Cartilage oligomeric matrix protein: COMPopathies and beyond. Matrix Biol 2018; 71-72:161-173. [PMID: 29530484 PMCID: PMC6129439 DOI: 10.1016/j.matbio.2018.02.023] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 02/27/2018] [Accepted: 02/27/2018] [Indexed: 02/06/2023]
Abstract
Cartilage oligomeric matrix protein (COMP) is a large pentameric glycoprotein that interacts with multiple extracellular matrix proteins in cartilage and other tissues. While, COMP is known to play a role in collagen secretion and fibrillogenesis, chondrocyte proliferation and mechanical strength of tendons, the complete range of COMP functions remains to be defined. COMPopathies describe pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED), two skeletal dysplasias caused by autosomal dominant COMP mutations. The majority of the mutations are in the calcium binding domains and compromise protein folding. COMPopathies are ER storage disorders in which the retention of COMP in the chondrocyte ER stimulates overwhelming cellular stress. The retention causes oxidative and inflammation processes leading to chondrocyte death and loss of long bone growth. In contrast, dysregulation of wild-type COMP expression is found in numerous diseases including: fibrosis, cardiomyopathy and breast and prostate cancers. The most exciting clinical application is the use of COMP as a biomarker for idiopathic pulmonary fibrosis and cartilage degeneration associated osteoarthritis and rheumatoid and, as a prognostic marker for joint injury. The ever expanding roles of COMP in single gene disorders and multifactorial diseases will lead to a better understanding of its functions in ECM and tissue homeostasis towards the goal of developing new therapeutic avenues.
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Affiliation(s)
- Karen L Posey
- McGovern Medical School, UTHealth, Department of Pediatrics, United States.
| | - Francoise Coustry
- McGovern Medical School, UTHealth, Department of Pediatrics, United States
| | - Jacqueline T Hecht
- McGovern Medical School, UTHealth, Department of Pediatrics, United States; UTHealth, School of Dentistry, United States
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Denton N, Pinnick KE, Karpe F. Cartilage oligomeric matrix protein is differentially expressed in human subcutaneous adipose tissue and regulates adipogenesis. Mol Metab 2018; 16:172-179. [PMID: 30100245 PMCID: PMC6157646 DOI: 10.1016/j.molmet.2018.07.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 07/17/2018] [Accepted: 07/23/2018] [Indexed: 12/15/2022] Open
Abstract
Objective The composition of the extracellular matrix (ECM) impacts adipocyte function and might determine adipose tissue (AT) function and distribution. Cartilage oligomeric matrix protein (COMP), a matricellular protein usually studied in bone and cartilage, is highly differentially expressed between subcutaneous abdominal and gluteal AT. This study aimed to explore COMP's role in human subcutaneous abdominal and gluteal AT and preadipocyte biology. Methods COMP mRNA levels were measured in whole AT and immortalised preadipocytes via quantitative (q)-PCR. Tissue and cellular COMP protein were measured via Western blot and immunohistochemistry; plasma COMP was measured by ELISA. The effect of COMP on adipogenesis in immortalised preadipocytes was evaluated by qPCR of adipogenic markers and cellular triacylglycerol (TAG) accumulation. Results qPCR analysis of paired subcutaneous abdominal and gluteal AT biopsies (n = 190) across a range of BMI (20.7–45.5 kg/m2) indicated ∼3-fold higher COMP expression in gluteal AT (P = 1.7 × 10−31); protein levels mirrored this. Immunohistochemistry indicated COMP was abundant in gluteal AT ECM and co-localised with collagen-1. AT COMP mRNA levels and circulating COMP protein levels were positively associated with BMI/adiposity but unrelated to AT distribution. COMP expression changed dynamically during adipogenesis (time × depot, P = 0.01). Supplementation of adipogenic medium with exogenous COMP protein (500 ng/ml) increased PPARG2 expression ∼1.5-fold (P = 0.0003) and TAG accumulation ∼1.25-fold in abdominal and gluteal preadipocytes (P = 0.02). Conclusions We confirmed that COMP is an ECM protein which is differentially expressed between subcutaneous abdominal and gluteal AT. Despite its depot-specific expression pattern, however, AT COMP mRNA levels and plasma COMP concentration correlated positively with overall obesity but not body fat distribution. Exogenous COMP enhanced adipogenesis. These data identify COMP as a novel regulator of AT and highlight the importance of the ECM to AT biology. COMP is a matricellular protein which is abundant in bone and cartilage. COMP is differentially expressed between subcutaneous abdominal and gluteal AT. COMP expression was positively correlated with overall AT mass but not distribution. COMP promoted adipogenesis in subcutaneous abdominal and gluteal preadipocytes. COMP represents a novel regulator of AT biology that resides in the ECM.
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Affiliation(s)
- Nathan Denton
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Katherine E Pinnick
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; NIHR Oxford Biomedical Research Centre, Oxford University Hospital NHS Foundation Trust, Oxford, UK.
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Chakkalakal SA, Heilig J, Baumann U, Paulsson M, Zaucke F. Impact of Arginine to Cysteine Mutations in Collagen II on Protein Secretion and Cell Survival. Int J Mol Sci 2018; 19:ijms19020541. [PMID: 29439465 PMCID: PMC5855763 DOI: 10.3390/ijms19020541] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 02/04/2018] [Accepted: 02/06/2018] [Indexed: 12/27/2022] Open
Abstract
Inherited point mutations in collagen II in humans affecting mainly cartilage are broadly classified as chondrodysplasias. Most mutations occur in the glycine (Gly) of the Gly-X-Y repeats leading to destabilization of the triple helix. Arginine to cysteine substitutions that occur at either the X or Y position within the Gly-X-Y cause different phenotypes like Stickler syndrome and congenital spondyloepiphyseal dysplasia (SEDC). We investigated the consequences of arginine to cysteine substitutions (X or Y position within the Gly-X-Y) towards the N and C terminus of the triple helix. Protein expression and its secretion trafficking were analyzed. Substitutions R75C, R134C and R704C did not alter the thermal stability with respect to wild type; R740C and R789C proteins displayed significantly reduced melting temperatures (Tm) affecting thermal stability. Additionally, R740C and R789C were susceptible to proteases; in cell culture, R789C protein was further cleaved by matrix metalloproteinases (MMPs) resulting in expression of only a truncated fragment affecting its secretion and intracellular retention. Retention of misfolded R740C and R789C proteins triggered an ER stress response leading to apoptosis of the expressing cells. Arginine to cysteine mutations towards the C-terminus of the triple helix had a deleterious effect, whereas mutations towards the N-terminus of the triple helix (R75C and R134C) and R704C had less impact.
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Affiliation(s)
- Salin A Chakkalakal
- Center for Research in FOP and Related Disorders, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Juliane Heilig
- Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany.
- Cologne Center for Musculoskeletal Biomechanics (CCMB), 50931 Cologne, Germany.
| | - Ulrich Baumann
- Institute of Biochemistry, University of Cologne, 50931 Cologne, Germany.
| | - Mats Paulsson
- Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany.
- Cologne Center for Musculoskeletal Biomechanics (CCMB), 50931 Cologne, Germany.
- Cluster of Excellence Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany.
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany.
| | - Frank Zaucke
- Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany.
- Cologne Center for Musculoskeletal Biomechanics (CCMB), 50931 Cologne, Germany.
- Dr. Rolf M. Schwiete Research Unit for Osteoarthritis, Orthopedic University Hospital Friedrichsheim, 60528 Frankfurt/Main, Germany.
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Mutant cartilage oligomeric matrix protein (COMP) compromises bone integrity, joint function and the balance between adipogenesis and osteogenesis. Matrix Biol 2018; 67:75-89. [PMID: 29309831 DOI: 10.1016/j.matbio.2017.12.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/23/2017] [Accepted: 12/27/2017] [Indexed: 12/23/2022]
Abstract
Mutations in COMP (cartilage oligomeric matrix protein) cause severe long bone shortening in mice and humans. Previously, we showed that massive accumulation of misfolded COMP in the ER of growth plate chondrocytes in our MT-COMP mouse model of pseudoachondroplasia (PSACH) causes premature chondrocyte death and loss of linear growth. Premature chondrocyte death results from activation of oxidative stress and inflammation through the CHOP-ER pathway and is reduced by removing CHOP or by anti-inflammatory or antioxidant therapies. Although the mutant COMP chondrocyte pathologic mechanism is now recognized, the effect of mutant COMP on bone quality and joint health (laxity) is largely unknown. Applying multiple analytic approaches, we describe a novel mechanism by which the deleterious consequences of mutant COMP retention results in upregulation of miR-223 disturbing the adipogenesis - osteogenesis balance. This results in reduction in bone mineral density, bone quality, mechanical strength and subchondral bone thickness. These, in addition to abnormal patterns of ossification at the ends of the femoral bones likely contribute to precocious osteoarthritis (OA) of the hips and knees in the MT-COMP mouse and PSACH. Moreover, joint laxity is compromised by abnormally thin ligaments. Altogether, these novel findings align with the PSACH phenotype of delayed ossification and bone age, extreme joint laxity and joint erosion, and extend our understanding of the underlying processes that affect bone in PSACH. These results introduce a novel finding that miR-223 is involved in the ossification defect in MT-COMP mice making it a therapeutic target.
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12
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Lubricin binds cartilage proteins, cartilage oligomeric matrix protein, fibronectin and collagen II at the cartilage surface. Sci Rep 2017; 7:13149. [PMID: 29030641 PMCID: PMC5640667 DOI: 10.1038/s41598-017-13558-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 09/26/2017] [Indexed: 01/09/2023] Open
Abstract
Lubricin, a heavily O-glycosylated protein, is essential for boundary lubrication of articular cartilage. Strong surface adherence of lubricin is required given the extreme force it must withstand. Disulfide bound complexes of lubricin and cartilage oligomeric matrix protein (COMP) have recently been identified in arthritic synovial fluid suggesting they may be lost from the cartilage surface in osteoarthritis and inflammatory arthritis. This investigation was undertaken to localise COMP-lubricin complexes within cartilage and investigate if other cartilage proteins are involved in anchoring lubricin to the joint. Immunohistochemical analysis of human cartilage biopsies showed lubricin and COMP co-localise to the cartilage surface. COMP knockout mice, however, presented with a lubricin layer on the articular cartilage leading to the further investigation of additional lubricin binding mechanisms. Proximity ligation assays (PLA) on human cartilage biopsies was used to localise additional lubricin binding partners and demonstrated that lubricin bound COMP, but also fibronectin and collagen II on the cartilage surface. Fibronectin and collagen II binding to lubricin was confirmed and characterised by solid phase binding assays with recombinant lubricin fragments. Overall, COMP, fibronectin and collagen II bind lubricin, exposed on the articular cartilage surface suggesting they may be involved in maintaining essential boundary lubrication.
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Quantitative evaluation of the relationship between COMP promoter methylation and the susceptibility and curve progression of adolescent idiopathic scoliosis. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2017; 27:272-277. [DOI: 10.1007/s00586-017-5309-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 08/12/2017] [Accepted: 09/20/2017] [Indexed: 01/26/2023]
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14
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Posey KL, Hecht JT. Novel therapeutic interventions for pseudoachondroplasia. Bone 2017; 102:60-68. [PMID: 28336490 PMCID: PMC6168010 DOI: 10.1016/j.bone.2017.03.045] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 02/28/2017] [Accepted: 03/20/2017] [Indexed: 12/31/2022]
Abstract
Pseudoachondroplasia (PSACH), a severe short-limbed dwarfing condition, is associated with life-long joint pain and early onset osteoarthritis. PSACH is caused by mutations in cartilage oligomeric matrix protein (COMP), a pentameric matricellular protein expressed primarily in cartilage and other musculoskeletal tissues. Mutations in COMP diminish calcium binding and as a result perturb protein folding and export to the extracellular matrix. Mutant COMP is retained in the endoplasmic reticulum (ER) of growth plate chondrocytes resulting in massive intracellular COMP retention. COMP trapped in the ER builds an intracellular matrix network that may prevent the normal cellular clearance mechanisms. We have shown that accumulation of intracellular matrix in mutant-COMP (MT-COMP) mice stimulates intense unrelenting ER stress, inflammation and oxidative stress. This cytotoxic stress triggers premature death of growth plate chondrocytes limiting long-bone growth. Here, we review the mutant COMP pathologic mechanisms and anti-inflammatory/antioxidant therapeutic approaches to reduce ER stress. In MT-COMP mice, aspirin and resveratrol both dampen the mutant COMP chondrocyte phenotype by decreasing intracellular accumulation, chondrocyte death and inflammatory marker expression. This reduction in chondrocyte stress translates into an improvement in long-bone growth in the MT-COMP mice. Our efforts now move to translational studies targeted at reducing the clinical consequences of MT-COMP and painful sequelae associated with PSACH.
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Affiliation(s)
- Karen L Posey
- McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, United States.
| | - Jacqueline T Hecht
- McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, United States; School of Dentistry University of Texas Heath, Houston, TX, United States
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15
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Gamal R, Elsayed SM, EL-Sobky TA, Elabd HS. Pseudoachondroplasia in a child: The role of anthropometric measurements and skeletal imaging in differential diagnosis. THE EGYPTIAN JOURNAL OF RADIOLOGY AND NUCLEAR MEDICINE 2017. [DOI: 10.1016/j.ejrnm.2016.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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16
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Posey KL, Coustry F, Veerisetty AC, Hossain M, Gattis D, Booten S, Alcorn JL, Seth PP, Hecht JT. Antisense Reduction of Mutant COMP Reduces Growth Plate Chondrocyte Pathology. Mol Ther 2017; 25:705-714. [PMID: 28162960 DOI: 10.1016/j.ymthe.2016.12.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 11/28/2016] [Accepted: 12/25/2016] [Indexed: 01/25/2023] Open
Abstract
Mutations in cartilage oligomeric matrix protein cause pseudoachondroplasia, a severe disproportionate short stature disorder. Mutant cartilage oligomeric matrix protein produces massive intracellular retention of cartilage oligomeric matrix protein, stimulating ER and oxidative stresses and inflammation, culminating in post-natal loss of growth plate chondrocytes, which compromises linear bone growth. Treatments for pseudoachondroplasia are limited because cartilage is relatively avascular and considered inaccessible. Here we report successful delivery and treatment using antisense oligonucleotide technology in our transgenic pseudoachondroplasia mouse model. We demonstrate delivery of human cartilage oligomeric matrix protein-specific antisense oligonucleotides to cartilage and reduction of cartilage oligomeric matrix protein expression, which largely alleviates pseudoachondroplasia growth plate chondrocyte pathology. One antisense oligonucleotide reduced steady-state levels of cartilage oligomeric matrix protein mRNA and dampened intracellular retention of mutant cartilage oligomeric matrix protein, leading to a reduction of inflammatory markers and cell death and partial restoration of proliferation. This novel and exciting work demonstrates that antisense-based therapy is a viable approach for treating pseudoachondroplasia and other human cartilage disorders.
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Affiliation(s)
- Karen L Posey
- Department of Pediatrics, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA.
| | - Francoise Coustry
- Department of Pediatrics, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA
| | - Alka C Veerisetty
- Department of Pediatrics, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA
| | - Mohammad Hossain
- Department of Pediatrics, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA
| | - Danielle Gattis
- Department of Antisense Drug Discovery, Ionis Pharmaceuticals, Inc., Carlsbad, CA 92010, USA
| | - Sheri Booten
- Department of Antisense Drug Discovery, Ionis Pharmaceuticals, Inc., Carlsbad, CA 92010, USA
| | - Joseph L Alcorn
- Department of Pediatrics, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA
| | - Punit P Seth
- Department of Antisense Drug Discovery, Ionis Pharmaceuticals, Inc., Carlsbad, CA 92010, USA
| | - Jacqueline T Hecht
- Department of Pediatrics, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA
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17
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Hecht JT, Sage EH. Retention of the Matricellular Protein SPARC in the Endoplasmic Reticulum of Chondrocytes from Patients with Pseudoachondroplasia. J Histochem Cytochem 2016; 54:269-74. [PMID: 16286662 DOI: 10.1369/jhc.5c6834.2005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pseudoachondroplasia (PSACH) is an autosomal dominant disease characterized by dwarfism, morphological irregularities of long bones and hips, and early-onset osteoarthritis. This disease has been attributed to mutations in a structural protein of the cartilage extracellular matrix (ECM), cartilage oligomeric matrix protein (COMP), which result in its selective retention in the chondrocyte rough endoplasmic reticulum (ER). Accumulation of excessive amounts of mutated COMP might reflect a defect in protein trafficking by PSACH chondrocytes. Here we identify the matricellular protein SPARC as a component of this trafficking deficit. SPARC was localized to the hypertrophic chondrocytes in the normal human tibial growth plate and in cultured control cartilage nodules. In contrast, concentrated intracellular depots of SPARC were identified in nodules cultured from three PSACH patients with mutations in COMP. The accumulated SPARC was coincident with COMP and with protein disulfide isomerase, a resident chaperone of the rough ER, whereas SPARC and COMP were not coincident in the ECM of control or PSACH nodules. SPARC-null mice develop severe osteopenia and degenerative intervertebral disc disease, and exhibit attenuation of collagenous ECM. The retention of SPARC in the ER of chondrocytes producing mutant COMP indicates a new intracellular function for SPARC in the trafficking/secretion of cartilage ECM.
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Affiliation(s)
- Jacqueline T Hecht
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, Texas, USA
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18
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Wang YC, Liu JS, Chen JY, Wu SQ, Wang GR, Nie J, Zhang SK, Guo QL, Luo JM. Multiple functions of the first EGF domain in matrilin-3: Secretion and endoplasmic reticulum stress. Int J Mol Med 2015; 36:1648-56. [PMID: 26499313 DOI: 10.3892/ijmm.2015.2377] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 10/02/2015] [Indexed: 11/06/2022] Open
Abstract
Mutations in matrilin-3 are associated with common skeletal diseases, such as hand osteoarthritis (HOA), as well as rare chondrodysplasias, such as multiple epiphyseal dysplasia (MED) and spondyloepimetaphyseal dysplasia (SEMD). In the present study, we constructed the mutations R116W [at the von Willebrand factor, type A (vWFA) domain], T298M [at the first epidermal growth factor (EGF) domain] and C299S (at the first EGF domain), according to the mouse sequence, which are associated with human MED, HOA and SEMD, respectively, by overlap extension PCR and inserted them into an expression vector (pcDNA3.1/v5-His). We transfected these contructs into the COS-1 or MCT cells, and the results revealed that the HOA-related matrilin-3 mutation (T298M) leads to a high expression level of growth arrest DNA damage-inducible gene 153 (GADD153, also known as CHOP; an endoplasmic reticulum stress marker), as shown by western blot analysis and does not significantly affect protein secretion, as shown by immunofluorescence staining; however, osteochondroplasia, i.e., MED-related (R116W) and SEMD-related (C299S) mutations lead to both high levels of GADD153 expression and protein trafficking into the cytoplasm and form multiple vacuoles in cells, which in turn leads to insufficient protein secretion.
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Affiliation(s)
- Yi-Chun Wang
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Jing-Shi Liu
- Department of Critical Care Medicine, The Affiliated Cancer Hospital of Xiangya Medical School, Central South University, Changsha, Hunan 410013, P.R. China
| | - Jun-Yi Chen
- Department of Critical Care Medicine, The Affiliated Cancer Hospital of Xiangya Medical School, Central South University, Changsha, Hunan 410013, P.R. China
| | - Sheng-Qi Wu
- Central Laboratory, The Affiliated Cancer Hospital of Xiangya Medical School, Central South University, Changsha, Hunan 410013, P.R. China
| | - Gui-Rong Wang
- Department of Surgery, SUNY Upstate Medical University College of Medicine, Syracuse, NY 13210, USA
| | - Jing Nie
- Department of Critical Care Medicine, The Affiliated Cancer Hospital of Xiangya Medical School, Central South University, Changsha, Hunan 410013, P.R. China
| | - Shu-Kun Zhang
- Department of Pathology, Qinghai People's Provincial Hospital, Xining, Qinghai 810007, P.R. China
| | - Qu-Lian Guo
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Jun-Ming Luo
- Department of Pathology, Qinghai People's Provincial Hospital, Xining, Qinghai 810007, P.R. China
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19
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BRIGGS MICHAELD, BELL PETERA, PIROG KATARZYNAA. The utility of mouse models to provide information regarding the pathomolecular mechanisms in human genetic skeletal diseases: The emerging role of endoplasmic reticulum stress (Review). Int J Mol Med 2015; 35:1483-92. [PMID: 25824717 PMCID: PMC4432922 DOI: 10.3892/ijmm.2015.2158] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 03/30/2015] [Indexed: 11/22/2022] Open
Abstract
Genetic skeletal diseases (GSDs) are an extremely diverse and complex group of rare genetic diseases that primarily affect the development and homeostasis of the osseous skeleton. There are more than 450 unique and well-characterised phenotypes that range in severity from relatively mild to severe and lethal forms. Although individually rare, as a group of related genetic diseases, GSDs have an overall prevalence of at least 1 per 4,000 children. Qualitative defects in cartilage structural proteins result in a broad spectrum of both recessive and dominant GSDs. This review focused on a disease spectrum resulting from mutations in the non-collagenous glycoproteins, cartilage oligomeric matrix protein (COMP) and matrilin-3, which together cause a continuum of phenotypes that are amongst the most common autosomal dominant GSDs. Pseudoachondroplasia (PSACH) and autosomal dominant multiple epiphyseal dysplasia (MED) comprise a disease spectrum characterised by varying degrees of disproportionate short stature, joint pain and stiffness and early-onset osteoarthritis. Over the past decade, the generation and deep phenotyping of a range of genetic mouse models of the PSACH and MED disease spectrum has allowed the disease mechanisms to be characterised in detail. Moreover, the generation of novel phenocopies to model specific disease mechanisms has confirmed the importance of endoplasmic reticulum (ER) stress and reduced chondrocyte proliferation as key modulators of growth plate dysplasia and reduced bone growth. Finally, new insight into related musculoskeletal complications (such as myopathy and tendinopathy) has also been gained through the in-depth analysis of targeted mouse models of the PSACH-MED disease spectrum.
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Affiliation(s)
- MICHAEL D. BRIGGS
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne, NE1 3BZ, UK
| | - PETER A. BELL
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne, NE1 3BZ, UK
| | - KATARZYNA A. PIROG
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne, NE1 3BZ, UK
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20
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Posey KL, Coustry F, Veerisetty AC, Hossain M, Alcorn JL, Hecht JT. Antioxidant and anti-inflammatory agents mitigate pathology in a mouse model of pseudoachondroplasia. Hum Mol Genet 2015; 24:3918-28. [PMID: 25859006 DOI: 10.1093/hmg/ddv122] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 04/07/2015] [Indexed: 12/22/2022] Open
Abstract
Pseudoachondroplasia (PSACH), a severe short-limb dwarfing condition, results from mutations that cause misfolding of the cartilage oligomeric matrix protein (COMP). Accumulated COMP in growth plate chondrocytes activates endoplasmic reticulum stress, leading to inflammation and chondrocyte death. Using a MT-COMP mouse model of PSACH that recapitulates the molecular and clinical PSACH phenotype, we previously reported that oxidative stress and inflammation play important and unappreciated roles in PSACH pathology. In this study, we assessed the ability of antioxidant and anti-inflammatory agents to affect skeletal and cellular pathology in our mouse model of PSACH. Treatment of MT-COMP mice with aspirin or resveratrol from birth to P28 decreased mutant COMP intracellular retention and chondrocyte cell death, and restored chondrocyte proliferation. Inflammatory markers associated with cartilage degradation and eosinophils were present in the joints of untreated juvenile MT-COMP mice, but were undetectable in treated mice. Most importantly, these treatments resulted in significantly increased femur length. This is the first and only therapeutic approach shown to mitigate both the chondrocyte and long-bone pathology of PSACH in a mouse model and suggests that reducing inflammation and oxidative stress early in the disease process may be a novel approach to treat this disorder.
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Affiliation(s)
- Karen L Posey
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, TX, USA and
| | - Francoise Coustry
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, TX, USA and
| | - Alka C Veerisetty
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, TX, USA and
| | - Mohammad Hossain
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, TX, USA and
| | - Joseph L Alcorn
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, TX, USA and
| | - Jacqueline T Hecht
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, TX, USA and Shriners Hospital for Children, Houston, TX, USA
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21
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He W, Kienzle A, Liu X, Müller WEG, Feng Q. In vitro 30 nm silver nanoparticles promote chondrogenesis of human mesenchymal stem cells. RSC Adv 2015. [DOI: 10.1039/c5ra06386h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Silver nanoparticles positively influence chondrogenesis of human mesenchymal stem cells through promoting expression of chondrogenic markers while reducing hypertrophy.
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Affiliation(s)
- Wei He
- State Key Laboratory of New Ceramics and Fine Processing
- School of Materials Science and Engineering
- Tsinghua University
- Beijing 100084
- China
| | - Arne Kienzle
- Institute for Physiological Chemistry
- Medical Center of the Johannes Gutenberg-University Mainz
- D-55128 Mainz
- Germany
| | - Xujie Liu
- State Key Laboratory of New Ceramics and Fine Processing
- School of Materials Science and Engineering
- Tsinghua University
- Beijing 100084
- China
| | - Werner E. G. Müller
- Institute for Physiological Chemistry
- Medical Center of the Johannes Gutenberg-University Mainz
- D-55128 Mainz
- Germany
| | - Qingling Feng
- State Key Laboratory of New Ceramics and Fine Processing
- School of Materials Science and Engineering
- Tsinghua University
- Beijing 100084
- China
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22
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Posey KL, Alcorn JL, Hecht JT. Pseudoachondroplasia/COMP - translating from the bench to the bedside. Matrix Biol 2014; 37:167-73. [PMID: 24892720 PMCID: PMC4209947 DOI: 10.1016/j.matbio.2014.05.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 05/19/2014] [Accepted: 05/19/2014] [Indexed: 12/31/2022]
Abstract
Pseudoachondroplasia (PSACH) is a skeletal dysplasia characterized by disproportionate short stature, small hands and feet, abnormal joints and early onset osteoarthritis. PSACH is caused by mutations in thrombospondin-5 (TSP-5, also known as cartilage oligomeric matrix protein or COMP), a pentameric extracellular matrix protein primarily expressed in chondrocytes and musculoskeletal tissues. The thrombospondin gene family is composed of matricellular proteins that associate with the extracellular matrix (ECM) and regulate processes in the matrix. Mutations in COMP interfere with calcium-binding, protein conformation and export to the extracellular matrix, resulting in inappropriate intracellular COMP retention. This accumulation of misfolded protein is cytotoxic and triggers premature death of chondrocytes during linear bone growth, leading to shortened long bones. Both in vitro and in vivo models have been employed to study the molecular processes underlying development of the PSACH pathology. Here, we compare the strengths and weaknesses of current mouse models of PSACH and discuss how the resulting phenotypes may be translated to clinical therapies.
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Affiliation(s)
- Karen LaShea Posey
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, TX 77030, USA.
| | - Joseph L Alcorn
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, TX 77030, USA
| | - Jacqueline T Hecht
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, TX 77030, USA; Shriners Hospital for Children, Houston, TX 77030, USA
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23
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Patterson SE, Dealy CN. Mechanisms and models of endoplasmic reticulum stress in chondrodysplasia. Dev Dyn 2014; 243:875-93. [DOI: 10.1002/dvdy.24131] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 03/10/2014] [Accepted: 03/17/2014] [Indexed: 12/14/2022] Open
Affiliation(s)
- Sara E. Patterson
- Center for Regenerative Medicine and Skeletal Development; Department of Reconstructive Sciences; University of Connecticut Health Center; Farmington Connecticut
| | - Caroline N. Dealy
- Center for Regenerative Medicine and Skeletal Development; Department of Reconstructive Sciences; University of Connecticut Health Center; Farmington Connecticut
- Center for Regenerative Medicine and Skeletal Development; Department of Orthopedic Surgery; University of Connecticut Health Center; Farmington Connecticut
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24
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Piróg KA, Irman A, Young S, Halai P, Bell PA, Boot-Handford RP, Briggs MD. Abnormal chondrocyte apoptosis in the cartilage growth plate is influenced by genetic background and deletion of CHOP in a targeted mouse model of pseudoachondroplasia. PLoS One 2014; 9:e85145. [PMID: 24558358 PMCID: PMC3928032 DOI: 10.1371/journal.pone.0085145] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 11/23/2013] [Indexed: 11/18/2022] Open
Abstract
Pseudoachondroplasia (PSACH) is an autosomal dominant skeletal dysplasia caused by mutations in cartilage oligomeric matrix protein (COMP) and characterised by short limbed dwarfism and early onset osteoarthritis. Mouse models of PSACH show variable retention of mutant COMP in the ER of chondrocytes, however, in each case a different stress pathway is activated and the underlying disease mechanisms remain largely unknown. T585M COMP mutant mice are a model of moderate PSACH and demonstrate a mild ER stress response. Although mutant COMP is not retained in significant quantities within the ER of chondrocytes, both BiP and the pro-apoptotic ER stress-related transcription factor CHOP are mildly elevated, whilst bcl-2 levels are decreased, resulting in increased and spatially dysregulated chondrocyte apoptosis. To determine whether the abnormal chondrocyte apoptosis observed in the growth plate of mutant mice is CHOP-mediated, we bred T585M COMP mutant mice with CHOP-null mice to homozygosity, and analysed the resulting phenotype. Although abnormal apoptosis was alleviated in the resting zone following CHOP deletion, the mutant growth plates were generally more disorganised. Furthermore, the bone lengths of COMP mutant CHOP null mice were significantly shorter at 9 weeks of age when compared to the COMP mutant mice, including a significant difference in the skull length. Overall, these data demonstrate that CHOP-mediated apoptosis is an early event in the pathobiology of PSACH and suggest that the lack of CHOP, in conjunction with a COMP mutation, may lead to aggravation of the skeletal phenotype via a potentially synergistic effect on endochondral ossification.
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Affiliation(s)
- Katarzyna A. Piróg
- Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom
- * E-mail: (KAP); (MDB)
| | - Andreja Irman
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester, United Kingdom
| | - Siobhan Young
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester, United Kingdom
| | - Poonam Halai
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester, United Kingdom
| | - Peter A. Bell
- Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Raymond P. Boot-Handford
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester, United Kingdom
| | - Michael D. Briggs
- Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom
- * E-mail: (KAP); (MDB)
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25
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Posey KL, Coustry F, Veerisetty AC, Liu P, Alcorn JL, Hecht JT. Chondrocyte-specific pathology during skeletal growth and therapeutics in a murine model of pseudoachondroplasia. J Bone Miner Res 2014; 29:1258-68. [PMID: 24194321 PMCID: PMC4075045 DOI: 10.1002/jbmr.2139] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 10/24/2013] [Accepted: 11/01/2013] [Indexed: 11/10/2022]
Abstract
Mutations in the gene encoding cartilage oligomeric matrix protein (COMP) cause pseudoachondroplasia (PSACH), a severe dwarfing condition. Pain, a significant complication, has generally been attributed to joint abnormalities and erosion and early onset osteoarthritis. Previously, we found that the inflammatory-related transcripts were elevated in growth plate and articular cartilages, indicating that inflammation plays an important role in the chondrocyte disease pathology and may contribute to the overall pain sequelae. Here, we describe the effects of D469-delCOMP expression on the skeleton and growth plate chondrocytes with the aim to define a treatment window and thereby reduce pain. Consistent with the human PSACH phenotype, skeletal development of D469del-COMP mice was normal and similar to controls at birth. By postnatal day 7 (P7), the D469del-COMP skeleton, limbs, skull and snout were reduced and this reduction was progressive during postnatal growth, resulting in a short-limbed dwarfed mouse. Modulation of prenatal and postnatal expression of D469del-COMP showed minimal retention/cell death at P7 with some retention/cell death by P14, suggesting that earlier treatment intervention at the time of PSACH diagnosis may produce optimal results. Important and novel findings were an increase in inflammatory proteins generally starting at P21 and that exercise exacerbates inflammation. These observations suggest that pain in PSACH may be related to an intrinsic inflammatory process that can be treated symptomatically and is not related to early joint erosion. We also show that genetic ablation of CHOP dampens the inflammatory response observed in mice expressing D469del-COMP. Toward identifying potential treatments, drugs known to decrease cellular stress (lithium, phenylbutyric acid, and valproate) were assessed. Interestingly, all diminished the chondrocyte pathology but had untoward outcomes on mouse growth, development, and longevity. Collectively, these results define an early treatment window in which chondrocytes can be salvaged, thereby potentially increasing skeletal growth and decreasing pain.
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Affiliation(s)
- Karen L Posey
- Department of Pediatrics, University of Texas Medical School at Houston, TX, USA
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26
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Severe Spinal Cord Injury Causes Immediate Multi-cellular Dysfunction at the Chondro-Osseous Junction. Transl Stroke Res 2013; 2:643-50. [PMID: 22368723 DOI: 10.1007/s12975-011-0118-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Spinal cord injury is associated with rapid bone loss and arrested long bone growth due to mechanisms that are poorly understood. In this study, we sought to determine the effects of severe T10 contusion spinal cord injury on the sublesional bone microenvironment in adolescent rats. A severe lower thoracic (vertebral T10) spinal cord injury was generated by weight drop (10 g×50 mm). Severely injured and body weight-matched uninjured male Sprague-Dawley rats were studied. At 3 and 5 days post-injury, we performed histological analysis of the distal femoral metaphysis, TUNEL assay, immunohistochemistry, real-time PCR, and western blot analysis compared to uninjured controls. We observed severe hindlimb functional deficits typical of this model. We detected uncoupled remodeling with increased osteoclast activity in the absence of osteoblast activity. We detected osteoblast, osteocyte, and chondrocyte apoptosis with suppressed osteoblast and chondrocyte proliferation and growth plate arrest due to spinal cord injury. We also detected altered gene expression in both whole bone extracts and bone marrow monocytes following spinal cord injury. We conclude that spinal cord injury results in altered gene expression of key regulators of osteoblast and chondrocyte activity. This leads to premature cellular apoptosis, suppressed cellular proliferation, growth plate arrest, and uncoupled bone remodeling in sublesional bone with unopposed osteoclastic resorption.
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Unlu G, Levic DS, Melville DB, Knapik EW. Trafficking mechanisms of extracellular matrix macromolecules: insights from vertebrate development and human diseases. Int J Biochem Cell Biol 2013; 47:57-67. [PMID: 24333299 DOI: 10.1016/j.biocel.2013.11.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Revised: 11/01/2013] [Accepted: 11/10/2013] [Indexed: 12/19/2022]
Abstract
Cellular life depends on protein transport and membrane traffic. In multicellular organisms, membrane traffic is required for extracellular matrix deposition, cell adhesion, growth factor release, and receptor signaling, which are collectively required to integrate the development and physiology of tissues and organs. Understanding the regulatory mechanisms that govern cargo and membrane flow presents a prime challenge in cell biology. Extracellular matrix (ECM) secretion remains poorly understood, although given its essential roles in the regulation of cell migration, differentiation, and survival, ECM secretion mechanisms are likely to be tightly controlled. Recent studies in vertebrate model systems, from fishes to mammals and in human patients, have revealed complex and diverse loss-of-function phenotypes associated with mutations in components of the secretory machinery. A broad spectrum of diseases from skeletal and cardiovascular to neurological deficits have been linked to ECM trafficking. These discoveries have directly challenged the prevailing view of secretion as an essential but monolithic process. Here, we will discuss the latest findings on mechanisms of ECM trafficking in vertebrates.
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Affiliation(s)
- Gokhan Unlu
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Daniel S Levic
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - David B Melville
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Ela W Knapik
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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Xie X, Liao L, Gao J, Luo X. A novel COMP mutation in a Chinese patient with pseudoachondroplasia. Gene 2013; 522:102-6. [PMID: 23562786 DOI: 10.1016/j.gene.2013.02.056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 02/16/2013] [Accepted: 02/19/2013] [Indexed: 10/27/2022]
Abstract
A 2.75-year-old Chinese boy presented with typical clinical features of pseudoachondroplasia, including disproportionate short-limb short stature, brachydactyly, genu varus and waddling gait. Radiologically, tubular bones were short with widened metaphyses, irregular and small epiphyses; anterior tonguing or beaking of vertebral bodies were characteristic. DNA sequencing analysis of the COMP gene revealed a heterozygous mutation (c.1511G>A, p.Cys504Tyr) in the patient but his parents were unaffected without this genetic change. The missense mutation (c.1511G>A) was not found in 100 healthy controls and has not been reported previously. Our findings expand the spectrum of known mutations in COMP leading to pseudoachondroplasia.
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Affiliation(s)
- Xuemei Xie
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
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29
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Skory RM, Bernabé BP, Galdones E, Broadbelt LJ, Shea LD, Woodruff TK. Microarray analysis identifies COMP as the most differentially regulated transcript throughout in vitro follicle growth. Mol Reprod Dev 2013; 80:132-44. [PMID: 23242557 DOI: 10.1002/mrd.22144] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 12/09/2012] [Indexed: 12/15/2022]
Abstract
In vitro follicle growth has emerged as a technology that can provide new information about folliculogenesis and serve as part of a suite of methods currently under development to assist women whose fertility is threatened by cancer treatments. Though it has been shown that in vitro-grown follicles secrete peptide and steroid hormones, much of the follicular transcriptome remains unknown. Thus, microarray analysis was performed to characterize the transcriptome and secretome of in vitro-grown follicles. One prominently regulated gene product was cartilage oligomeric matrix protein (Comp): its mRNA was upregulated during the final 4 days of culture (P < 0.05) and COMP protein could be detected in medium from individual follicles. COMP expression localized to mural granulosa cells of large antral follicles both in vitro and in vivo, with maximal expression immediately preceding ovulation in cycling and chorionic gonadotropin-primed female mice. COMP was co-expressed with two known markers of follicle maturation, inhibin β(A) and gremlin, and was expressed only in TUNEL-negative follicles. In addition to other gene products identified in the microarray, COMP has potential utility as a marker of follicle maturation.
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Affiliation(s)
- Robin M Skory
- Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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30
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Coustry F, Posey KL, Liu P, Alcorn JL, Hecht JT. D469del-COMP retention in chondrocytes stimulates caspase-independent necroptosis. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:738-48. [PMID: 22154936 PMCID: PMC3349870 DOI: 10.1016/j.ajpath.2011.10.033] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 10/19/2011] [Accepted: 10/23/2011] [Indexed: 12/31/2022]
Abstract
Mutations in the cartilage oligomeric matrix protein gene (COMP) cause pseudoachondroplasia (PSACH). This dysplasia results from the intracellular retention of mutant COMP protein and premature death of growth-plate chondrocytes. Toward better understanding of these underlying mechanisms, we examined D469del-COMP activation of the unfolded protein response and cell death pathways in rat chondrosarcoma cells. Using an inducible expression system, we examined the effects of D469del-COMP retention after 4 days of mRNA expression and then 5 days without inducing agent. Retention of D469del-COMP stimulated Chop (Ddit3) and Gadd34 (Ppp1r15a) and triggered reactivation of protein translation that exacerbated intracellular retention. High levels of Nox4 and endoplasmic reticulum receptor stress-inducible Ero1β generated reactive oxygen species, causing oxidative stress. Increased expression of Gadd genes and presence of γH2AX indicated that DNA damage was occurring. The presence of cleaved apoptosis inducing factor (tAIF) and the absence of activated caspases indicated that retention of D469del-COMP triggers cell death in chondrocytes by necroptosis, a caspase-independent programmed necrosis. Loss of growth-plate chondrocytes by necroptosis was also found in our pseudoachondroplasia mouse model. These results suggest a model in which D469del-COMP expression induces persistent endoplasmic reticulum stress, oxidative stress, and DNA damage, thus priming chondrocytes for necroptosis. We define for the first time the precise mechanisms underlying D469del-COMP pathology in pseudoachondroplasia and suggest that oxidative stress and AIF may be promising therapeutic targets.
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Affiliation(s)
- Françoise Coustry
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, Texas
| | - Karen L. Posey
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, Texas
| | - Peiman Liu
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, Texas
| | - Joseph L. Alcorn
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, Texas
| | - Jacqueline T. Hecht
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, Texas
- Shriners Hospital for Children, Houston, Texas
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31
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Chop (Ddit3) is essential for D469del-COMP retention and cell death in chondrocytes in an inducible transgenic mouse model of pseudoachondroplasia. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 180:727-37. [PMID: 22154935 DOI: 10.1016/j.ajpath.2011.10.035] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 10/19/2011] [Accepted: 10/23/2011] [Indexed: 11/21/2022]
Abstract
Cartilage oligomeric matrix protein (COMP), a secreted glycoprotein synthesized by chondrocytes, regulates proliferation and type II collagen assembly. Mutations in the COMP gene cause pseudoachondroplasia and multiple epiphyseal dysplasia. Previously, we have shown that expression of D469del-COMP in transgenic mice causes intracellular retention of D469del-COMP, thereby recapitulating pseudoachondroplasia chondrocyte pathology. This inducible transgenic D469del-COMP mouse is the only in vivo model to replicate the critical cellular and clinical features of pseudoachondroplasia. Here, we report developmental studies of D469del-COMP-induced chondrocyte pathology from the prenatal period to adolescence. D469del-COMP retention was limited prenatally and did not negatively affect the growth plate until 3 weeks after birth. Results of immunostaining, transcriptome analysis, and qRT-PCR suggest a molecular model in which D469del-COMP triggers apoptosis during the first postnatal week. By 3 weeks (when most chondrocytes are retaining D469del-COMP), inflammation, oxidative stress, and DNA damage contribute to chondrocyte cell death by necroptosis. Importantly, by crossing the D469del-COMP mouse onto a Chop null background (Ddit3 null), thereby eliminating Chop, the unfolded protein response was disrupted, thus alleviating both D469del-COMP intracellular retention and premature chondrocyte cell death. Chop therefore plays a significant role in processes that mediate D469del-COMP retention. Taken together, these results suggest that there may be an optimal window before the induction of significant D469del-COMP retention during which endoplasmic reticulum stress could be targeted.
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Suleman F, Gualeni B, Gregson HJ, Leighton MP, Piróg KA, Edwards S, Holden P, Boot-Handford RP, Briggs MD. A novel form of chondrocyte stress is triggered by a COMP mutation causing pseudoachondroplasia. Hum Mutat 2011; 33:218-31. [PMID: 22006726 PMCID: PMC3320758 DOI: 10.1002/humu.21631] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 09/16/2011] [Indexed: 12/23/2022]
Abstract
Pseudoachondroplasia (PSACH) results from mutations in cartilage oligomeric matrix protein (COMP) and the p.D469del mutation within the type III repeats of COMP accounts for approximately 30% of PSACH. To determine disease mechanisms of PSACH in vivo, we introduced the Comp D469del mutation into the mouse genome. Mutant animals were normal at birth but grew slower than their wild-type littermates and developed short-limb dwarfism. In the growth plates of mutant mice chondrocyte columns were reduced in number and poorly organized, while mutant COMP was retained within the endoplasmic reticulum (ER) of cells. Chondrocyte proliferation was reduced and apoptosis was both increased and spatially dysregulated. Previous studies on COMP mutations have shown mutant COMP is co-localized with chaperone proteins, and we have reported an unfolded protein response (UPR) in mouse models of PSACH-MED (multiple epiphyseal dysplasia) harboring mutations in Comp (T585M) and Matn3, Comp etc (V194D). However, we found no evidence of UPR in this mouse model of PSACH. In contrast, microarray analysis identified expression changes in groups of genes implicated in oxidative stress, cell cycle regulation, and apoptosis, which is consistent with the chondrocyte pathology. Overall, these data suggest that a novel form of chondrocyte stress triggered by the expression of mutant COMP is central to the pathogenesis of PSACH.
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Affiliation(s)
- Farhana Suleman
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
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Cao LH, Wang LB, Wang SS, Ma HW, Ji CY, Luo Y. Identification of novel and recurrent mutations in the calcium binding type III repeats of cartilage oligomeric matrix protein in patients with pseudoachondroplasia. GENETICS AND MOLECULAR RESEARCH 2011; 10:955-63. [PMID: 21644213 DOI: 10.4238/vol10-2gmr1111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Pseudoachondroplasia is an autosomal dominant osteochondrodysplasia characterized by disproportionate short stature, joint laxity, and early onset osteoarthrosis. Pseudoachondroplasia is caused by mutations in the gene encoding cartilage oligomeric matrix protein (COMP). We looked for mutations in the COMP gene in three sporadic Chinese pseudoachondroplasia patients and identified two novel mutations, c.1189G>T (p.D397Y) and c.1220G>A (p.C407Y), and one recurrent mutation, c.1318G>C (p.G440R), in the calcium binding type III repeats of COMP. This study confirms the relationship between mutations of the COMP gene and clinical findings of pseudoachondroplasia; it also provides evidence for the importance of the calcium binding domains to the functioning of COMP.
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Affiliation(s)
- L H Cao
- Research Center for Medical Genomics, China Medical University, Shenyang, China
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34
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Fendri K, Moldovan F. Potential role of COMP as a biomarker for adolescent idiopathic scoliosis. Med Hypotheses 2011; 76:762-3. [PMID: 21339053 DOI: 10.1016/j.mehy.2011.01.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 01/31/2011] [Indexed: 10/18/2022]
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Hansen U, Platz N, Becker A, Bruckner P, Paulsson M, Zaucke F. A secreted variant of cartilage oligomeric matrix protein carrying a chondrodysplasia-causing mutation (p.H587R) disrupts collagen fibrillogenesis. ACTA ACUST UNITED AC 2011; 63:159-67. [PMID: 20936634 DOI: 10.1002/art.30073] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Mutations in human cartilage oligomeric matrix protein (COMP) cause multiple epiphyseal dysplasia or pseudoachondroplasia. Electron microscopic analyses of patient biopsy tissue have shown that, in most cases, mutated COMP is retained in granular or lamellar inclusions in the endoplasmic reticulum of chondrocytes. However, some mutations that do not interfere with protein trafficking, resulting in normal secretion of the mutated protein, have been identified. These mutations are likely to cause the chondrodysplasia phenotype, via events that occur after secretion. The aim of the present study was to identify such extracellular mechanisms associated with the pathogenesis of chondrodysplasias. METHODS A mutated but secreted COMP variant, p.H587R, as well as wild-type COMP were recombinantly expressed and purified from cell culture supernatants. Since recent studies have shown that COMP can facilitate collagen fibrillogenesis in vitro, the effect of the p.H587R mutation on this process was determined by analyzing the kinetics of fibrillogenesis in vitro and determining the structure of the collagen fibrils formed by immunogold electron microscopy. RESULTS Mutated p.H587R COMP accelerated fibril formation by type I collagen in vitro to a slightly greater extent than that with wild-type COMP. However, p.H587R COMP induced aggregation and disorganization of fibril intermediates and end products. Mixtures of cartilage collagens or of type XI collagen alone produced similar results. The addition of p.H587R COMP to preformed fibrils induced aggregation and fusion of the fibrils, whereas wild-type COMP had little effect. CONCLUSION The mutant COMP variant p.H587R generally interferes with normal collagen organization during fibrillogenesis. This constitutes a novel pathogenetic mechanism of COMP-associated chondrodysplasias.
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Affiliation(s)
- Uwe Hansen
- University Hospital of Muenster, Muenster, Germany
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36
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37
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Otten C, Hansen U, Talke A, Wagener R, Paulsson M, Zaucke F. A matrilin-3 mutation associated with osteoarthritis does not affect collagen affinity but promotes the formation of wider cartilage collagen fibrils. Hum Mutat 2010; 31:254-63. [PMID: 20077500 DOI: 10.1002/humu.21182] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Mutations in matrilin-3 have been associated with common skeletal diseases like osteoarthritis as well as with the rare chondrodysplasias MED and SEMD. We have previously shown that the mutations p.R116W and p.C299S, associated with MED and SEMD, respectively, cause retention of matrilin-3 within the endoplasmic reticulum of primary chondrocytes, while the mutation associated with osteoarthritis, p.T298M, does not hinder secretion. The present study focused on the consequences of the p.T298M mutation on the structure of matrilin-3 and on the role of matrilin-3 in the formation of a functional extracellular matrix. Analysis of recombinant full-length matrilin-3 revealed that the p.T298M mutation does not influence oligomerization of matrilin-3 or its proteolytic processing by ADAMTS-4 and -5. Nevertheless, structural analyses indicate local conformational changes. These changes do not affect the affinity for collagens II, IX, XI, or COMP, but have a major impact on the in vitro fibrillogenesis of collagen II/IX/XI heterofibrils.
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Affiliation(s)
- Christiane Otten
- Center for Biochemistry, Medical Faculty, University of Cologne, D-50931 Cologne, Germany
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38
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Tsang KY, Chan D, Bateman JF, Cheah KSE. In vivo cellular adaptation to ER stress: survival strategies with double-edged consequences. J Cell Sci 2010; 123:2145-54. [PMID: 20554893 DOI: 10.1242/jcs.068833] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Disturbances to the balance of protein synthesis, folding and secretion in the endoplasmic reticulum (ER) induce stress and thereby the ER stress signaling (ERSS) response, which alleviates this stress. In this Commentary, we review the emerging idea that ER stress caused by abnormal physiological conditions and/or mutations in genes that encode client proteins of the ER is a key factor underlying different developmental processes and the pathology of diverse diseases, including diabetes, neurodegeneration and skeletal dysplasias. Recent studies in mouse models indicate that the effect of ERSS in vivo and the nature of the cellular strategies induced to ameliorate pathological ER stress are crucial factors in determining cell fate and clinical disease features. Importantly, ERSS can affect cellular proliferation and the differentiation program; cells that survive the stress can become 'reprogrammed' or dysfunctional. These cell-autonomous adaptation strategies can generate a spectrum of context-dependent cellular consequences, ranging from recovery to death. Secondary effects can include altered cell-extracellular-matrix interactions and non-cell-autonomous alteration of paracrine signaling, which contribute to the final phenotypic outcome. Recent reports showing that ER stress can be alleviated by chemical compounds suggest the potential for novel therapeutic approaches.
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Affiliation(s)
- Kwok Yeung Tsang
- Department of Biochemistry and Centre for Reproduction, Development and Growth, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China
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Roman-Blas J, Dion AS, Seghatoleslami MR, Giunta K, Oca P, Jimenez SA, Williams CJ. MED and PSACH COMP mutations affect chondrogenesis in chicken limb bud micromass cultures. J Cell Physiol 2010; 224:817-26. [PMID: 20578249 DOI: 10.1002/jcp.22185] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Mutations in cartilage oligomeric matrix protein (COMP) cause pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED). We studied the effects of over-expression of wild type and mutant COMP on early stages of chondrogenesis in chicken limb bud micromass cultures. Cells were transduced with RCAS virus harboring wild type or mutant (C328R, PSACH; T585R, MED) COMP cDNAs and cultured for 3, 4, and 5 days. The effect of COMP constructs on chondrogenesis was assessed by analyzing mRNA and protein expression of several COMP binding partners. Cell viability was assayed, and evaluation of apoptosis was performed by monitoring caspase 3 processing. Over-expression of COMP, and especially expression of COMP mutants, had a profound affect on the expression of syndecan 3 and tenascin C, early markers of chondrogenesis. Over-expression of COMP did not affect levels of type II collagen or matrilin-3; however, there were increases in type IX collagen expression and sulfated proteoglycan synthesis, particularly at day 5 of harvest. In contrast to cells over-expressing COMP, cells with mutant COMP showed reduction in type IX collagen expression and increased matrilin 3 expression. Finally, reduction in cell viability, and increased activity of caspase 3, at days 4 and 5, were observed in cultures expressing either wild type or mutant COMP. MED, and PSACH mutations, despite displaying phenotypic differences, demonstrated only subtle differences in their cellular viability and mRNA and protein expression of components of the extracellular matrix, including those that interact with COMP. These results suggest that COMP mutations, by disrupting normal interactions between COMP and its binding partners, significantly affect chondrogenesis.
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Affiliation(s)
- J Roman-Blas
- Division of Rheumatology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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40
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Rieubland C, Jacquemont S, Mittaz L, Osterheld MC, Vial Y, Superti-Furga A, Unger S, Bonafé L. Phenotypic and molecular characterization of a novel case of dyssegmental dysplasia, Silverman-Handmaker type. Eur J Med Genet 2010; 53:294-8. [PMID: 20542149 DOI: 10.1016/j.ejmg.2010.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Accepted: 06/01/2010] [Indexed: 11/19/2022]
Abstract
Dyssegmental dysplasia, Silverman-Handmaker type (DDSH; #MIM 224410) is an autosomal recessive form of lethal dwarfism characterized by a defect in segmentation and fusion of vertebral bodies components ("anisospondyly") and by severe limb shortening. It is caused by mutations in the perlecan gene (HSPG2), but so far, only three molecularly confirmed cases have been reported. We report a novel case of DDSH in a fetus that presented at 15 weeks gestation with encephalocele, severe micromelic dwarfism and narrow thorax. After termination of pregnancy, radiographs showed short ribs, short and bent long bones and anisospondyly of two vertebral bodies. The fetus was homozygous for a previously undescribed null mutation in HSPG2.
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Affiliation(s)
- Claudine Rieubland
- Division of Medical Genetics, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
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41
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Posey KL, Liu P, Wang HR, Veerisetty AC, Alcorn JL, Hecht JT. RNAi reduces expression and intracellular retention of mutant cartilage oligomeric matrix protein. PLoS One 2010; 5:e10302. [PMID: 20421976 PMCID: PMC2858657 DOI: 10.1371/journal.pone.0010302] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Accepted: 03/12/2010] [Indexed: 01/06/2023] Open
Abstract
Mutations in cartilage oligomeric matrix protein (COMP), a large extracellular glycoprotein expressed in musculoskeletal tissues, cause two skeletal dysplasias, pseudoachondroplasia and multiple epiphyseal dysplasia. These mutations lead to massive intracellular retention of COMP, chondrocyte death and loss of growth plate chondrocytes that are necessary for linear growth. In contrast, COMP null mice have only minor growth plate abnormalities, normal growth and longevity. This suggests that reducing mutant and wild-type COMP expression in chondrocytes may prevent the toxic cellular phenotype causing the skeletal dysplasias. We tested this hypothesis using RNA interference to reduce steady state levels of COMP mRNA. A panel of shRNAs directed against COMP was tested. One shRNA (3B) reduced endogenous and recombinant COMP mRNA dramatically, regardless of expression levels. The activity of the shRNA against COMP mRNA was maintained for up to 10 weeks. We also demonstrate that this treatment reduced ER stress. Moreover, we show that reducing steady state levels of COMP mRNA alleviates intracellular retention of other extracellular matrix proteins associated with the pseudoachondroplasia cellular pathology. These findings are a proof of principle and the foundation for the development of a therapeutic intervention based on reduction of COMP expression.
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Affiliation(s)
- Karen L Posey
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, Texas, United States of America.
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42
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Cartilage oligomeric matrix protein promotes cell attachment via two independent mechanisms involving CD47 and alphaVbeta3 integrin. Mol Cell Biochem 2009; 338:215-24. [PMID: 20033473 DOI: 10.1007/s11010-009-0355-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 12/03/2009] [Indexed: 10/20/2022]
Abstract
Cartilage oligomeric matrix protein (COMP) is a pentameric approximately 524 kDa multidomain extracellular matrix protein and is the fifth member of the thrombospondin family. COMP is abundantly expressed in proliferating and hypertrophic chondrocytes of the growth plate, articular cartilage, synovium, tendon, and ligament. The spatial localization of COMP highlights its importance in the phenotypes of pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED), COMP disorders that are characterized by disproportionate short stature, brachydactyly, scoliosis, early-onset osteoarthritis, and joint hypermobility. In this study, the role of COMP in ligament was investigated with a series of cell attachment assays using ligament cells binding to COMP. A dose-dependent cell attachment activity was found, which was inhibited by a peptide containing the SFYVVMWK amino acid sequence derived from the globular C-terminal domain of COMP. This activity was independent of the recently described RGD-dependent attachment activity. Function-blocking antibodies to CD47 and alphaVbeta3 integrin reduced cell attachment to COMP, implicating the participation of these cell surface molecules in COMP cell binding. Immunofluorescence studies showed that cell attachment to COMP induced the formation of lamellae containing F-actin microspikes associated with fascin. We propose that COMP promotes cell attachment via two independent mechanisms involving cell surface CD47 and alphaVbeta3 integrin and that a consequence of cell attachment to COMP is the specific induction of fascin-stabilized actin microspikes.
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43
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Posey KL, Veerisetty AC, Liu P, Wang HR, Poindexter BJ, Bick R, Alcorn JL, Hecht JT. An inducible cartilage oligomeric matrix protein mouse model recapitulates human pseudoachondroplasia phenotype. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:1555-63. [PMID: 19762713 PMCID: PMC2751552 DOI: 10.2353/ajpath.2009.090184] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/01/2009] [Indexed: 11/20/2022]
Abstract
Cartilage oligomeric matrix protein (COMP) is a pentameric extracellular protein expressed in cartilage and other musculoskeletal tissues. Mutations in the COMP gene cause pseudoachondroplasia (PSACH), a severe dwarfing condition that has a growth plate chondrocyte pathology. PSACH is characterized by intracellular retention of COMP and other extracellular matrix (ECM) proteins, which form an ordered matrix within large rough endoplasmic reticulum cisternae. This accumulation is cytotoxic and causes premature chondrocyte cell death, thereby depleting chondrocytes needed for normal long bone growth. Research to define the underlying molecular mechanisms of PSACH has been hampered by the lack of a suitable model system. In this study, we achieved robust expression of human mutant (MT) or wild-type (WT) COMP in mice by using a tetracycline-inducible promoter. Normal growth plate distribution of ECM proteins was observed in 1-month-old WT-COMP and C57BL\6 control mice. In contrast, the structure of the MT-COMP growth plate recapitulated the findings of human PSACH growth plate morphology, including (1) retention of ECM proteins, (2) intracellular matrix formation in the rER cisternae, and (3) increased chondrocyte apoptosis. Therefore, we have generated the first mouse model to show extensive intracellular retention of ECM proteins recapitulating the human PSACH disease process at the cellular level.
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Affiliation(s)
- Karen L Posey
- Department of Pediatrics, University of Texas Medical School, Houston, TX 77030, USA
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Kim MS, Wu KY, Auyeung V, Chen Q, Gruppuso PA, Phornphutkul C. Leucine restriction inhibits chondrocyte proliferation and differentiation through mechanisms both dependent and independent of mTOR signaling. Am J Physiol Endocrinol Metab 2009; 296:E1374-82. [PMID: 19401455 PMCID: PMC2692404 DOI: 10.1152/ajpendo.91018.2008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Linear growth in children is sensitive to nutritional status. Amino acids, in particular leucine, have been shown to regulate cell growth, proliferation, and differentiation through the mammalian target of rapamycin (mTOR), a nutrient-sensing protein kinase. Having recently demonstrated a role for mTOR in chondrogenesis, we hypothesized that leucine restriction, acting through mTOR, would inhibit growth plate chondrocyte proliferation and differentiation. The effect of leucine restriction was compared with that of the specific mTOR inhibitor, rapamycin. Leucine restriction produced a dose-dependent inhibition of fetal rat metatarsal explant growth. This was accounted by reduced cell proliferation and hypertrophy but not apoptosis. mTOR activity, as reflected by ribosomal protein S6 phosphorylation, was only partially inhibited by leucine restriction, whereas rapamycin abolished S6 phosphorylation. In chondrogenic ATDC5 cells, leucine restriction inhibited cell number, proteoglycan accumulation, and collagen X expression despite minimal inhibition of mTOR. Microarray analysis demonstrated that the effect of leucine restriction on ATDC5 cell gene expression differed from that of rapamycin. Out of 1,571 genes affected by leucine restriction and 535 genes affected by rapamycin, only 176 genes were affected by both. These findings indicate that the decreased chondrocyte growth and differentiation associated with leucine restriction is only partly attributable to inhibition of mTOR signaling. Thus nutrient restriction appears to directly modulate bone growth through unidentified mTOR-independent mechanisms in addition to the well-characterized mTOR nutrient-sensing pathway.
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Affiliation(s)
- Mimi S Kim
- Division of Pediatric Endocrinology and Metabolism, Rhode Island Hospital, 593 Eddy St., Providence, RI 02903, USA
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Alcorn JL, Merritt TM, Farach-Carson MC, Wang HH, Hecht JT. Ribozyme-mediated reduction of wild-type and mutant cartilage oligomeric matrix protein (COMP) mRNA and protein. RNA (NEW YORK, N.Y.) 2009; 15:686-695. [PMID: 19237461 PMCID: PMC2661830 DOI: 10.1261/rna.1335909] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Accepted: 12/23/2008] [Indexed: 05/27/2023]
Abstract
Dominant-negative mutations in the homopentameric extracellular matrix glycoprotein cartilage oligomeric matrix protein (COMP) result in inappropriate intracellular retention of misfolded COMP in the rough endoplasmic reticulum of chondrocytes, causing chondrocyte cell death, which leads to two skeletal dysplasias: pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (EDM1). COMP null mice show no adverse effects on normal bone development and growth, suggesting a possible therapy involving removal of COMP mRNA. The goal of this study was to assess the ability of a hammerhead ribozyme (Ribo56, designed against the D469del mutation) to reduce COMP mRNA expression. In COS7 cells transfected with plasmids that overexpress wild-type or mutant COMP mRNA and Ribo56, the ribozyme reduced overexpressed normal COMP mRNA by 46% and mutant COMP mRNA by 56% in a dose-dependent manner. Surprisingly, the use of recombinant adenoviruses to deliver wild-type or mutant COMP mRNA and Ribo56 simultaneously into COS7 cells proved problematic for the activity of the ribozyme to reduce COMP expression. However, in normal human costochondral cells (hCCCs) infected only with adenoviruses expressing Ribo56, expression of endogenous wild-type COMP mRNA was reduced in a dose-dependent manner by 50%. In chondrocytes that contain heterozygous COMP mutations (D469del, G427E and D511Y) that cause PSACH, Ribo56 was more effective at reducing COMP mRNA (up to 70%). These results indicate that Ribo56 is effective at reducing mutant and wild-type COMP levels in cells and suggests a possible mode of therapy to reduce the mutant protein load.
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Affiliation(s)
- Joseph L Alcorn
- The Department of Pediatrics, The University of Texas Medical School at Houston, 77030, USA
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Tan K, Duquette M, Joachimiak A, Lawler J. The crystal structure of the signature domain of cartilage oligomeric matrix protein: implications for collagen, glycosaminoglycan and integrin binding. FASEB J 2009; 23:2490-501. [PMID: 19276170 DOI: 10.1096/fj.08-128090] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cartilage oligomeric matrix protein (COMP), or thrombospondin-5 (TSP-5), is a secreted glycoprotein that is important for growth plate organization and function. Mutations in COMP cause two skeletal dysplasias, pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (EDM1). In this study, we determined the structure of a recombinant protein that contains the last epidermal growth factor repeat, the type 3 repeats and the C-terminal domain (CTD) of COMP to 3.15-A resolution limit by X-ray crystallography. The CTD is a beta-sandwich that is composed of 15 antiparallel beta-strands, and the type 3 repeats are a contiguous series of calcium binding sites that associate with the CTD at multiple points. The crystal packing reveals an exposed potential metal-ion-dependent adhesion site (MIDAS) on one edge of the beta-sandwich that is common to all TSPs and may serve as a binding site for collagens and other ligands. Disease-causing mutations in COMP disrupt calcium binding, disulfide bond formation, intramolecular interactions, or sites for potential ligand binding. The structure presented here and its unique molecular packing in the crystal identify potential interactive sites for glycosaminoglycans, integrins, and collagens, which are key to cartilage structure and function.
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Affiliation(s)
- Kemin Tan
- Midwest Center for Structural Genomics, Biosciences Division, Argonne National Laboratory, Argonne, Illinois, USA
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Genetic diseases of connective tissues: cellular and extracellular effects of ECM mutations. Nat Rev Genet 2009; 10:173-83. [PMID: 19204719 DOI: 10.1038/nrg2520] [Citation(s) in RCA: 232] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Tissue-specific extracellular matrices (ECMs) are crucial for normal development and tissue function, and mutations in ECM genes result in a wide range of serious inherited connective tissue disorders. Mutations cause ECM dysfunction by combinations of two mechanisms. First, secretion of the mutated ECM components can be reduced by mutations affecting synthesis or by structural mutations causing cellular retention and/or degradation. Second, secretion of mutant protein can disturb crucial ECM interactions, structure and stability. Moreover, recent experiments suggest that endoplasmic reticulum (ER) stress, caused by mutant misfolded ECM proteins, contributes to the molecular pathology. Targeting ER stress might offer a new therapeutic strategy.
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Chen TLL, Posey KL, Hecht JT, Vertel BM. COMP mutations: domain-dependent relationship between abnormal chondrocyte trafficking and clinical PSACH and MED phenotypes. J Cell Biochem 2008; 103:778-87. [PMID: 17570134 DOI: 10.1002/jcb.21445] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Mutations in cartilage oligomeric matrix protein (COMP) produce clinical phenotypes ranging from the severe end of the spectrum, pseudoachondroplasia (PSACH), which is a dwarfing condition, to a mild condition, multiple epiphyseal dysplasia (MED). Patient chondrocytes have a unique morphology characterized by distended rER cisternae containing lamellar deposits of COMP and other extracellular matrix proteins. It has been difficult to determine why different mutations give rise to variable clinical phenotypes. Using our in vitro cell system, we previously demonstrated that the most common PSACH mutation, D469del, severely impedes trafficking of COMP and type IX collagen in chondrocytic cells, consistent with observations from patient cells. Here, we hypothesize that PSACH and MED mutations variably affect the cellular trafficking behavior of COMP and that the extent of defective trafficking correlates with clinical phenotype. Twelve different recombinant COMP mutations were expressed in rat chondrosarcoma cells and the percent cells with ER-retained COMP was assessed. For mutations in type 3 (T3) repeats, trafficking defects correlated with clinical phenotype; PSACH mutations had more cells retaining mutant COMP, while MED mutations had fewer. In contrast, the cellular trafficking pattern observed for mutations in the C-terminal globular domain (CTD) was not predictive of clinical phenotype. The results demonstrate that different COMP mutations in the T3 repeat domain have variable effects on intracellular transport, which correlate with clinical severity, while CTD mutations do not show such a correlation. These findings suggest that other unidentified factors contribute to the effect of the CTD mutations. J. Cell. Biochem. 103: 778-787, 2008. (c) 2007 Wiley-Liss, Inc.
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Affiliation(s)
- Tung-Ling L Chen
- Department of Cell Biology and Anatomy, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064, USA
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Zhang Y, Wang ZK, Luo JM, Kanbe K, Chen Q. Multiple functions of the von Willebrand Factor A domain in matrilins: secretion, assembly, and proteolysis. J Orthop Surg Res 2008; 3:21. [PMID: 18518980 PMCID: PMC2427018 DOI: 10.1186/1749-799x-3-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Accepted: 06/02/2008] [Indexed: 11/30/2022] Open
Abstract
The von Willebrand Factor A (vWF A) domain is one of the most widely distributed structural modules in cell-matrix adhesive molecules such as intergrins and extracellular matrix proteins. Mutations in the vWF A domain of matrilin-3 cause multiple epiphyseal dysplasia (MED), however the pathological mechanism remains to be determined. Previously we showed that the vWF A domain in matrilin-1 mediates formation of a filamentous matrix network through metal-ion dependent adhesion sites in the domain. Here we show two new functions of the vWF A domain in cartilage-specific matrilins (1 and 3). First, vWF A domain regulates oligomerization of matrilins. Insertion of a vWF A domain into matrilin-3 converts the formation of a mixture of matrilin-3 tetramer, trimer, and dimer into a tetramer only, while deletion of a vWF A domain from matrilin-1 converts the formation of the native matrilin-1 trimer into a mixture of trimer and dimer. Second, the vWF A domain protects matrilin-1 from proteolysis. We identified a latent proteolytic site next to the vWF A2 domain in matrilin-1, which is sensitive to the inhibitors of matrix proteases. Deletion of the abutting vWF A domain results in degradation of matrilin-1, presumably by exposing the adjacent proteolytic site. In addition, we also confirmed the vWF A domain is vital for the secretion of matrilin-3. Secretion of the mutant matrilin-3 harbouring a point mutation within the vWF A domain, as occurred in MED patients, is markedly reduced and delayed, resulting from intracellular retention of the mutant matrilin-3. Taken together, our data suggest that different mutations/deletions of the vWF A domain in matrilins may lead to distinct pathological mechanisms due to the multiple functions of the vWF A domain.
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Affiliation(s)
- Yue Zhang
- Cell and Molecular Biology Laboratory, Department of Orthopaedics, The Warren Alpert Medical School of Brown University/Rhode Island Hospital, Providence, Rhode Island, USA
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