COMP-assisted collagen secretion--a novel intracellular function required for fibrosis

Area of Science:

• Biochemistry
• Extracellular Matrix Biology
• Dermatology

Background:

• Cartilage oligomeric matrix protein (COMP) is a key extracellular matrix (ECM) component in load-bearing tissues.
• COMP functions as an adaptor, bridging ECM structures and interacting with collagen I and XII.
• Previous studies identified COMP in healthy skin and its induction during fibrosis.

Purpose of the Study:

• To investigate the functional role of COMP-collagen interactions in skin.
• To elucidate the intracellular functions of COMP.
• To assess the impact of COMP deficiency on fibrotic responses in mice.

Main Methods:

• Analysis of COMP-null fibroblasts and COMP-null mice.
• Assessment of collagen fibril morphology, density, and biomechanical properties of skin.
• Investigation of collagen secretion pathways and endoplasmic reticulum retention.

Main Results:

• Lack of COMP-collagen interaction altered collagen fibril morphology and skin biomechanics.
• COMP demonstrated an intracellular function in facilitating collagen secretion.
• COMP-null fibroblasts showed collagen retention in the endoplasmic reticulum.
• COMP-null mice exhibited significantly reduced skin fibrotic responses.
• Reintroduction of wild-type COMP restored collagen secretion.

Conclusions:

• COMP plays a critical, previously unrecognized intracellular role in controlling collagen secretion.
• COMP's function extends beyond ECM structure to regulate collagen export and fibrotic processes.
• Targeting COMP may offer new therapeutic strategies for fibrotic skin diseases.