Cartilage extracellular matrix proteoglycan (ACAN)

Cartilage extracellular matrix (ECM) proteoglycans are a diverse group of glycosylated proteins that are fundamental to the structural and mechanical properties of articular cartilage [1]. The most prominent member is aggrecan, a large aggregating proteoglycan that binds to hyaluronan to form massive complexes, creating a high fixed-charge density that attracts water and allows the cartilage to resist compressive forces [1, 5]. Other smaller proteoglycans, such as decorin and biglycan, are involved in regulating collagen fibril assembly and sequestering growth factors like TGF-beta and BMPs to modulate chondrocyte behavior [1, 8]. In degenerative joint diseases like osteoarthritis, these proteoglycans are the primary targets of enzymatic degradation by aggrecanases (ADAMTS-4 and ADAMTS-5) and matrix metalloproteinases (MMPs), leading to the loss of tissue elasticity and eventual joint failure [2, 5]. Therapeutic approaches focus on preserving these molecules by inhibiting catabolic enzymes, using anabolic growth factors like IGF-1 or FGF18 to stimulate their synthesis, or providing exogenous glycosaminoglycans to support matrix health [5, 6, 7]. Additionally, fragments of these proteoglycans, such as the ARGS neoepitope, serve as critical biomarkers for monitoring disease progression and the efficacy of disease-modifying osteoarthritis drugs (DMOADs) [1, 9].

Other names

AggrecanVersicanDecorinBiglycanFibromodulinLumicanPerlecanChondroitin sulfate proteoglycan 1CSPG1Large aggregating proteoglycan

Inhibition of degradative enzymes such as ADAMTS-4, ADAMTS-5, and MMPs; stimulation of anabolic pathways to increase proteoglycan synthesis; and direct supplementation of glycosaminoglycan building blocks to restore matrix integrity.