Collagen type I and collagen type III (COL1/COL3)

Collagen type I and collagen type III are the primary fibrillar collagens that constitute the majority of the interstitial extracellular matrix in vertebrates (UniProt). Collagen type I is the most abundant protein in the human body, providing high tensile strength to bone, skin, and tendons, while collagen type III is prevalent in extensible tissues such as the vasculature and lungs (PubMed). In healthy tissue, these collagens maintain structural integrity and facilitate cell-matrix interactions; however, their pathological accumulation is the hallmark of fibrosis in organs like the liver, lungs, and kidneys (NIH). Drugs targeting these collagens aim to halt or reverse fibrotic progression by inhibiting collagen synthesis, preventing the cross-linking that makes fibrotic tissue resistant to degradation, or directly dissolving collagen plaques as seen in Dupuytren's contracture (FDA). Monitoring serum levels of collagen-derived peptides, such as PIIINP, serves as a critical biomarker for assessing fibrotic activity and treatment response in clinical settings (NCBI).

Other names

Type I collagenType III collagenFibrillar collagenCOL1A1COL1A2COL3A1Alpha-1 type I collagenAlpha-1 type III collagen

Therapeutic interventions target these collagens through the inhibition of TGF-beta signaling to reduce synthesis, the inhibition of lysyl oxidase (LOX) enzymes to prevent fiber cross-linking, or the direct enzymatic cleavage of collagen fibers using exogenous collagenases (StatPearls, PubMed).