Cartilage oligomeric matrix protein: COMPopathies and beyond

Area of Science:

• Biochemistry and Molecular Biology
• Extracellular Matrix Research
• Skeletal Dysplasia Pathogenesis

Background:

• Cartilage oligomeric matrix protein (COMP) is a pentameric glycoprotein crucial for cartilage extracellular matrix (ECM) structure and function.
• COMP mutations cause skeletal dysplasias like pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED), leading to ER stress and chondrocyte death.
• Altered wild-type COMP expression is observed in diverse conditions, including fibrosis, cardiomyopathy, and cancers.

Purpose of the Study:

• To elucidate the multifaceted roles of COMP beyond its known functions in collagen secretion and chondrocyte proliferation.
• To explore the pathological mechanisms of COMP-related skeletal disorders (COMPopathies) and their implications for ECM homeostasis.
• To investigate the potential of COMP as a diagnostic and prognostic biomarker in various human diseases.

Main Methods:

• Analysis of COMP structure, function, and interactions within the extracellular matrix.
• Investigation of COMP mutation effects on protein folding, ER stress, and chondrocyte viability.
• Correlation of wild-type COMP expression levels with disease states such as fibrosis, cardiomyopathy, and cancer.

Main Results:

• COMP mutations primarily affect calcium-binding domains, leading to protein misfolding and endoplasmic reticulum (ER) retention, causing cellular stress and impaired bone growth.
• Dysregulation of wild-type COMP expression is associated with idiopathic pulmonary fibrosis, osteoarthritis, rheumatoid arthritis, and certain cancers.
• COMP demonstrates significant potential as a biomarker for diagnosing and predicting the progression of cartilage degeneration and joint injuries.

Conclusions:

• COMPopathies result from ER storage of misfolded COMP, triggering oxidative stress and inflammation, ultimately leading to chondrocyte death and growth defects.
• The expanding roles of COMP in both single-gene disorders and multifactorial diseases highlight its critical involvement in tissue homeostasis.
• COMP serves as a promising biomarker for various pathologies and presents therapeutic targets for developing novel treatment strategies.