PURPOSE: To investigate the effects of mutated cartilage oligomeric matrix protein (COMP) on the synthesis of cartilage-specific major matrix proteins of Swarm rat chondrosarcoma chondrocytes. MATERIALS AND METHODS: The Swarm rat chondrosarcoma chondrocytes transfected with chimeric construct consisting of a mutant gene of human COMP and an amino acid FLAG tag sequence were cultured in agarose gel. Formation of extracellular proteoglycan and type-II collagen of the cells were evaluated by immunohistochemical staining and measuring 35S-sulfate incorporation. RESULTS: No difference was observed in type-II collagen detection among the cell line expressing mutant COMP and control cell lines. Histochemical staining of sulfated proteoglycans with safranin-O showed lower amounts of proteoglycans were incorporated into the extracellular matrix of chondrocytes transfected with mutant gene. 35S-sulfate incorporation into the cell/matrix fractions demonstrates marked lower radiolabel incorporation compared to control cells. CONCLUSION: Mutation of COMP impacts the processing of proteoglycans rather than type-II collagen in three-dimensional culture of Swarm rat chondrosarcoma chondrocytes.
Animals ; Cartilage Oligomeric Matrix Protein* ; Cartilage* ; Cell Line* ; Chondrocytes ; Chondrosarcoma* ; Collagen ; Extracellular Matrix* ; Humans ; Proteoglycans ; Rats* ; Sepharose

This study aimed to report the clinical characteristics and COMP gene mutation of a family with pseudoachondroplasia (PSACH), a relatively rare spinal and epiphyseal dysplasia that is inherited as an autosomal dominant trait. Clinical information on a 5-year-2-month-old PSACH child and his parents was collected and analyzed. Diagnosis was confirmed by PCR amplification and direct sequencing of all the 19 exons and their flanking sequences of COMP gene, and the mutation was further ascertained by cloning analysis of exon 10. The child presented with short and stubby fingers, bow leg, short limb dwarfism and metaphysic broadening in long bone as well as lumbar lordosis. A mutation c.1048_1116del (p.Asn350_Asp372del) in exon 10, inherited from his father who did not demonstrate any phenotypic feature of PSACH, was detected in the child. PSACH was diagnosed definitively by means of COMP mutation analysis, on the basis of the child's clinical and imaging features. The non-penetrance phenomenon of COMP mutation was described for the first time in PSACH.
Achondroplasia ; genetics ; Cartilage Oligomeric Matrix Protein ; genetics ; Child, Preschool ; Cloning, Molecular ; Humans ; Male ; Mutation

OBJECTIVE: To detect the expression of cartilage oligomeric matrix protein (COMP) in the synovial chondromatosis of the temporomandibular joint (TMJSC), and to discuss the possible interactions between COMP, transforming growth factor (TGF)-β3, TGF-β1 and bone morphogenetic protein-2 (BMP-2) in the development of this neoplastic disease. METHODS: Patients in Peking University School and Hospital of Stomatology from January 2011 to February 2020 were selected, who had complete medical records, TMJSC was verified histologically after operation. The expressions of COMP, TGF-β3, TGF-β1 and BMP-2 in the TMJSC of the temporomandibular joint were detected by immunohistochemistry and quantitative real-time PCR (RT-PCR) at the protein level and mRNA level respectively, compared with the normal synovial tissue of temporomandibular joint. The histological morphology, protein expression and distribution of TMJSC tissues were observed microscopically, and the positive staining proteins were counted and scored. SPSS 22.0 statistical software was used to analyze the expression differences between the related proteins in TMJSC tissue and the normal synovial tissue of temporomandibular joint and to compare their differences. P < 0.05 indicated that the difference was statistically significant. RESULTS: Immunohistochemical results showed that the positive expression of COMP in TMJSC tissues was mostly found in synovial tissues and chondrocytes adjacent to synovial tissues, and the difference was statistically significant, compared with the normal temporomandibular joint synovial tissues. The positive expression of COMP was significantly different between recurrent TMJSC and non-recurrent ones. The positive expressions of TGF-β3, TGF-β1 and BMP-2 were higher than the normal synovial tissue, and were also mostly found in the synovial cells and adjacent chondrocytes, which was further confirmed by Western blot. According to the RT-PCR results, the expressions of COMP, TGF-β3, TGF-β1 and BMP-2 in TMJSC were higher than those in the normal synovial tissue. CONCLUSION The expression of COMP in TMJSC of temporomandibular joint increased significantly, compared with the normal synovial tissue. There may be interactions between COMP and cytokines related to the proliferation and differentiation, like TGF-β3, TGF-β1 and BMP-2, which may play a potential role in the pathogenesis of TMJSC.
Cartilage Oligomeric Matrix Protein/genetics* ; Chondromatosis, Synovial ; Humans ; Synovial Membrane ; Temporomandibular Joint ; Transforming Growth Factor beta3

BACKGROUNDMultiple epiphysis dysplasia (MED) is a common skeletal dysplasia with a significant locus heterogeneity. In the majority of clinically defined cases, mutations have been identified in the gene encoding cartilage algometric matrix protein (COMP).

METHODSFive patients were included in the study. Linkage analysis and mutation analysis of the COMP gene were conducted in the patients and their family members.

RESULTSWe have identified a novel mutation in axon 14 of COMP gene in the family.

CONCLUSIONSThis mutation produced a severe MED phenotype with marked short stature, early onset osteoarthritis, and remarkable radiographic changes. Our results extended the range of disease-causing mutations in COMP gene and contributed more information about relationship between mutations and phenotype.

Adolescent ; Asian Continental Ancestry Group ; Cartilage Oligomeric Matrix Protein ; genetics ; Female ; Humans ; Male ; Osteochondrodysplasias ; genetics ; Pedigree ; Point Mutation ; genetics

INTRODUCTIONTo prevent long-term unfavourable consequences to the articular cartilage of weight-bearing joints, serum biomarkers can be used to identify optimum loading of activities. This study aimed to investigate the circulation pattern of serum cartilage biomarkers in healthy adults in response to an uphill walk.

METHODSThis study recruited 58 healthy participants for the experimental group and 24 matched participants for the control group. Participants in the experimental group walked continuously for 14 km on a pathway with a 5.97° incline, while participants from the control group walked on a horizontal pathway. Serum was collected from both groups preactivity (i.e. T1), immediately after activity (i.e. T2) and 24 hours after T1 (i.e. T3). The serum cartilage oligomeric matrix protein (COMP), chondroitin sulfate-WF6 (WF6) and hyaluronic acid (HA) levels at each time point were quantified using enzyme-linked immunosorbent assays, and the results analysed.

RESULTSBoth groups shared similar demographic characteristics and activity duration. At T2, the serum COMP level of the experimental group was significantly higher than that of the control group, but the serum HA level of the experimental group was significantly lower than that of the control group. No significant difference between the serum WF6 levels of the experimental and control groups was observed at T2.

CONCLUSIONIncreasing levels of serum COMP demonstrate articular cartilage susceptibility to the increasing load. An unsustainable, high serum COMP level and an undetectable change in WF6 level were considered to be a reversible physiological change of the cartilage. A change in ser um HA level could be related to intensive physical activity and dynamic clearance rather than a change in cartilage structure.

Adolescent ; Adult ; Biomarkers ; blood ; Cartilage Oligomeric Matrix Protein ; blood ; Cartilage, Articular ; metabolism ; Chondroitin Sulfates ; blood ; Female ; Healthy Volunteers ; Humans ; Hyaluronic Acid ; blood ; Male ; Time Factors ; Walking ; Young Adult

OBJECTIVETo perform mutation analysis for a female with multiple epiphyseal dysplasia (MED) and provide pre-symptomatic and prenatal diagnosis.

METHODSMutation screening of cartilage oligomeric matrix protein (COMP) gene was carried out through targeted next-generation DNA sequencing and Sanger sequencing.

RESULTSA novel c.956 A>T resulting in substitution of Aspartic acid 319 for Valine (p.Asp319Val) has been identified in exon 9 of the COMP gene in the patient. As predicted by a SIFT software, above mutation can cause damage to the structure of COMP protein.

CONCLUSIONA novel c.956 A>T substitution mutation has been identified in a patient featuring MED.

Adult ; Base Sequence ; Cartilage Oligomeric Matrix Protein ; Exons ; Extracellular Matrix Proteins ; genetics ; Female ; Glycoproteins ; genetics ; Humans ; Matrilin Proteins ; Mutation ; Osteochondrodysplasias ; diagnosis ; genetics ; Polymorphism, Single Nucleotide ; Sequence Alignment

Cartilage oligomeric matrix protein (COMP) is a potential biomarker for joint destruction associated with osteoarthritis, which is first and best investigated biomarkers to reflect osteoarthritis occurs, progress and the prognosis. In this article, multiple uses and related reports of COMP are summarized briefly to promote further investigation of COMP.
Biomarkers ; blood ; Cartilage Oligomeric Matrix Protein ; Extracellular Matrix Proteins ; blood ; chemistry ; metabolism ; Glycoproteins ; blood ; chemistry ; metabolism ; Humans ; Matrilin Proteins ; Osteoarthritis ; blood ; diagnosis ; Prognosis

PURPOSE: Accumulating evidence suggests that microRNA-145 (miR-145) plays an important role in osteoarthritis (OA), which is a chronic progressive joint disease. Long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) promotes metastasis in cancers and functions as a sponge for miR-145. However, the role of MALAT1/miR-145 in OA pathogenesis has not yet been elucidated. MATERIALS AND METHODS: The expression of MALAT1 and miR-145 was examined by quantitative real-time PCR; the interaction between miR-145, MALAT1 and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 5 was verified by luciferase reporter assay. Correlations among MALAT1, miR-145, and ADAMTS5 were analyzed by Spearman rank analysis. Chondrocytes viability and cartilage extracellular matrix (ECM) degradation were investigated with cell viability assay and Western blotting analyzing expression of ADAMTS5, collagen type 2 alpha 1 (COL2A1), aggrecan (ACAN), and cartilage oligomeric matrix protein (COMP). RESULTS: MALAT1 was upregulated, and miR-145 was downregulated in OA samples and IL-1β-induced chondrocytes. Mechanically, miR-145 could directly bind to MALAT1 and ADAMTS5. Moreover, miR-145 expression was negatively correlated with MALAT1 and ADAMTS5 expression in OA patients, whereas MALAT1 and ADAMTS5 expression was positively correlated. Functionally, overexpression of MALAT1 inhibited chondrocyte viability and promoted cartilage ECM degradation in IL-1β-induced chondrocytes. In support thereof, MALAT1 silencing and miR-145 upregulation exerted the opposite effect in IL-1β-induced chondrocytes. Moreover, the effect of MALAT1 was counteracted by miR-145 upregulation, and ADAMTS5 restoration could abate miR-145 effects. CONCLUSION: An MALAT1/miR-145 axis contributes to ECM degradation in IL-1β-induced chondrocytes through targeting ADAMTS5, suggesting that MALAT1/miR-145/ADAMTS5 signaling may underlie human OA pathogenesis.
Adenocarcinoma ; Aggrecans ; Blotting, Western ; Cartilage Oligomeric Matrix Protein ; Cartilage ; Cell Survival ; Chondrocytes ; Collagen ; Extracellular Matrix ; Humans ; Joint Diseases ; Luciferases ; Lung ; Neoplasm Metastasis ; Osteoarthritis ; Porifera ; Real-Time Polymerase Chain Reaction ; RNA, Long Noncoding ; Temefos ; Thrombospondins ; Up-Regulation

In this paper we report the differentiating properties of platelet-rich plasma releasates (PRPr) on human chondrocytes within elastomeric polycaprolactone triol–citrate (PCLT–CA) porous scaffold. Human-derived chondrocyte cellular content of glycosaminoglycans (GAGs) and total collagen were determined after seeding into PCLT–CA scaffold enriched with PRPr cells. Immunostaining and real time PCR was applied to evaluate the expression levels of chondrogenic and extracellular gene markers. Seeding of chondrocytes into PCLT–CA scaffold enriched with PRPr showed significant increase in total collagen and GAGs production compared with chondrocytes grown within control scaffold without PRPr cells. The mRNA levels of collagen II and SOX9 increased significantly while the upregulation in Cartilage Oligomeric Matrix Protein (COMP) expression was statistically insignificant. We also report the reduction of the expression levels of collagen I and III in chondrocytes as a consequence of proximity to PRPr cells within the scaffold. Interestingly, the pre-loading of PRPr caused an increase of expression levels of following extracellular matrix (ECM) proteins: fibronectin, laminin and integrin β over the period of 3 days. Overall, our results introduce the PCLT–CA elastomeric scaffold as a new system for cartilage tissue engineering. The method of PRPr cells loading prior to chondrocyte culture could be considered as a potential environment for cartilage tissue engineering as the differentiation and ECM formation is enhanced significantly.
Blood Platelets* ; Cartilage Oligomeric Matrix Protein ; Cartilage* ; Chondrocytes ; Collagen ; Elastomers ; Extracellular Matrix* ; Fibronectins ; Glycosaminoglycans ; Humans* ; Laminin ; Methods ; Phenotype* ; Platelet-Rich Plasma ; Real-Time Polymerase Chain Reaction ; RNA, Messenger ; Tissue Engineering ; Up-Regulation

BACKGROUNDPseudoachondroplasia (PSACH) is an autosomal-dominant osteochondrodysplasia due to mutations in the gene encoding cartilage oligomeric matrix protein (COMP). Clinical diagnosis of PSACH is based primarily on family history, physical examination, and radiographic evaluation. There is evidence that decreased serum COMP concentration may serve as a diagnostic marker in PSACH. Here, we investigated the role of this gene and the serum COMP concentration in Chinese patients with PSACH.

METHODSA family with three patients and a sporadic case were recruited. Genomic and phenotypic data were recorded. The diagnosis of PSACH was made on the base of clinical evaluation. The genomic DNA was extracted from peripheral blood leukocytes. The 8-19 exons and flanking intron-exon boundary sequences of COMP were amplified by polymerase chain reaction (PCR) and screened for mutation by direct DNA sequencing. Serum COMP concentrations of 4 patients and age-compatible control group of 20 unrelated healthy subjects were analyzed on the basis of an ELISA Kit for human cartilage oligomeric matrix protein.

RESULTSA deletion (c.1447-1455del) was identified in exon 13 in the sporadic case. The mean serum COMP concentrations of four patients (3.12+/-2.28) were significantly lower than those of control group (10.86+/-2.21, P<0.05). There was no overlap in the distribution of serum COMP concentration between PSACH patients and controls.

CONCLUSIONSMutations in COMP gene are responsible for the PSACH. Serum COMP concentration may be suggested as an additional diagnostic marker to aid clinical findings in suspected cases of PSACH.

Cartilage Oligomeric Matrix Protein ; Child, Preschool ; Enzyme-Linked Immunosorbent Assay ; Exons ; genetics ; Extracellular Matrix Proteins ; blood ; genetics ; Female ; Glycoproteins ; blood ; genetics ; Humans ; Male ; Matrilin Proteins ; Mutation ; Osteochondrodysplasias ; blood ; genetics ; Pedigree ; Polymerase Chain Reaction