Dataset Information

COMP (Cartilage Oligomeric Matrix Protein) Neoepitope: A Novel Biomarker to Identify Symptomatic Carotid Stenosis.

ABSTRACT:

Objective

COMP (cartilage oligomeric matrix protein) is abundantly expressed in the cardiovascular system, cartilage, and atherosclerotic plaques. We investigated if the total COMP (COMPtotal) and COMP neoepitope (COMPneo) with other cardiovascular markers and clinical parameters could identify symptomatic carotid stenosis. Approach and Results: Blood samples were collected from patients with symptomatic carotid stenosis (stenosis, n=50), patients with stroke without carotid stenosis but small plaques (plaque, n=50), and control subjects (n=50). COMPtotal and COMPneo were measured using an ELISA. Ninety-two cardiovascular disease markers were measured by the Olink CVD kit. The presence of native COMP and COMPneo was determined by immunohistochemistry. The concentration of COMPneo was higher and COMPtotal was lower in the stenosis group. When the concentration was compared between the stenosis and control groups, IL-1ra (interleukin-1 receptor antagonist protein), IL6 (interleukin-6), REN (Renin), MMP1 (matrix metalloproteinase-1), TRAIL-R2 (tumor necrosis factor-related apoptosis-inducing ligand receptor 2), ITGB1BP2 (integrin beta 1 binding protein 2), and COMPneo were predictive of stenosis. Conversely, KLK6 (kallikrein-6), COMPtotal, NEMO (nuclear factor-kappa-B essential modulator), SRC (Proto-oncogene tyrosine-protein kinase Src), SIRT2 (SIR2-like protein), CD40 (cluster of differentiation 40), TF (tissue factor), MP (myoglobin), and RAGE (receptor for advanced glycation end-products) were predictive of the control group. Model reproducibility was good with the receiver operating characteristic plot area under the curve being 0.86. When comparing the plaque group and stenosis group, COMPneo, GAL (galanin), and PTX3 (pentraxin-related protein PTX3) were predictive of stenosis. Model reproducibility was excellent (receiver operating characteristic plot area under the curve 0.92). COMPneo was detected in smooth muscle-, endothelial-, and foam-cells in carotid stenosis.

Conclusions

Degradation of COMP may be associated with atherosclerosis progression and generation of a specific COMP fragment-COMPneo. This may represent a novel biomarker that together with COMPtotal and other risk-markers could be used to identify symptomatic carotid stenosis. Graphic Abstract: A graphic abstract is available for this article.

SUBMITTER: Sandstedt J

PROVIDER: S-EPMC7901532 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature

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COMP (Cartilage Oligomeric Matrix Protein) Neoepitope: A Novel Biomarker to Identify Symptomatic Carotid Stenosis.

Sandstedt Joakim J Vargmar Karin K Björkman Kristina K Ruetschi Ulla U Bergström Göran G Hultén Lillemor Mattsson LM Skiöldebrand Eva E

Arteriosclerosis, thrombosis, and vascular biology 20210121 3

<h4>Objective</h4>COMP (cartilage oligomeric matrix protein) is abundantly expressed in the cardiovascular system, cartilage, and atherosclerotic plaques. We investigated if the total COMP (COMPtotal) and COMP neoepitope (COMPneo) with other cardiovascular markers and clinical parameters could identify symptomatic carotid stenosis. Approach and Results: Blood samples were collected from patients with symptomatic carotid stenosis (stenosis, n=50), patients with stroke without carotid stenosis but ...[more]

PMID: 33472398

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Project description:BackgroundClinical tools to diagnose the early changes of osteoarthritis (OA) that occur in the articular cartilage are lacking.ObjectivesWe sought to identify and quantify a novel cartilage oligomeric matrix protein (COMP) neoepitope in the synovial fluid from the joints of healthy horses and those with different stages of OA.Study designIn vitro quantitative proteomics and assay development with application in synovial fluids samples obtained from biobanks of well-characterised horses.MethodsArticular cartilage explants were incubated with or without interleukin-1β for 25 days. Media were analysed via quantitative proteomics. Synovial fluid was obtained from either normal joints (n = 15) or joints causing lameness (n = 17) or with structural OA lesions (n = 7) and analysed for concentrations of the COMP neoepitope using a custom-developed inhibition enzyme-linked immunosorbent assay (ELISA). Explants were immunostained with polyclonal antibodies against COMP and the COMP neoepitopes.ResultsSemitryptic COMP peptides were identified and quantified in cell culture media from cartilage explants. A rabbit polyclonal antibody was raised against the neoepitope of the N-terminal portion of one COMP fragment (sequence SGPTHEGVC). An inhibition ELISA was developed to quantify the COMP neoepitope in synovial fluid. The mean concentration of the COMP neoepitope significantly increased in the synovial fluid from the joints responsible for acute lameness compared with normal joints and the joints of chronically lame horses and in joints with chronic structural OA. Immunolabelling for the COMP neoepitope revealed a pericellular staining in the interleukin-1β-stimulated explants.Main limitationsThe ELISA is based on polyclonal antisera rather than a monoclonal antibody.ConclusionsThe increase in the COMP neoepitope in the synovial fluid from horses with acute lameness suggests that this neoepitope has the potential to be a unique candidate biomarker for the early molecular changes in articular cartilage associated with OA.

Project description: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.

Project description:Primary chondrocytes dedifferentiate in serial monolayer with respect to their morphological and biosynthetic phenotype. They change from a round to a flattened fibroblast-like shape, and collagen I is secreted instead of the cartilage-specific collagen II. We analysed in detail the time course of dedifferentiation of mature bovine articular chondrocytes in monolayer for up to 32 weeks. Assessment of RNA expression by reverse transcription-PCR led to the identification of two novel phenotypical markers, the cartilage oligomeric matrix protein (COMP) and collagen IX, which are down-regulated faster than the widely accepted marker, collagen II. The different kinetics of COMP and collagen expression suggest differential regulation at the level of transcription. Immunostaining and metabolic labelling experiments confirmed the switch in the collagen expression pattern and the rapid down-regulation of de novo synthesis of COMP and collagen IX. Culture of chondrocytes in a three-dimensional matrix is known to stabilize the chondrocytic phenotype. We maintained cells for up to 28 weeks in an alginate bead system, which prevented dedifferentiation and led to a stabilization of collagen and COMP expression. Immunohistochemical analysis of the alginate beads revealed a similar distribution of matrix proteins to that found in vivo. Chondrocytes were transferred after a variable length of monolayer culture into the alginate matrix and the potential for redifferentiation was investigated. The re-expression of COMP and collagen IX was differentially regulated. The expression of COMP was re-induced within days after transfer into the three-dimensional matrix, while the expression of collagen IX was irreversibly down-regulated. In summary, these results demonstrate that the potential for redifferentiation decreases with increasing length of monolayer culture and show that the alginate bead system represents an attractive in vitro model to study the chondrocyte de- and re-differentiation processes, as well as extracellular matrix assembly.

Dataset Information

COMP (Cartilage Oligomeric Matrix Protein) Neoepitope: A Novel Biomarker to Identify Symptomatic Carotid Stenosis.

Objective

Conclusions

Publications

COMP (Cartilage Oligomeric Matrix Protein) Neoepitope: A Novel Biomarker to Identify Symptomatic Carotid Stenosis.

Similar Datasets

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