Heparan sulfate proteoglycan and extracellular matrix glycosaminoglycan (HSPG/GAG)

Heparan sulfate proteoglycans (HSPGs) and other extracellular matrix (ECM) glycosaminoglycans (GAGs) are complex glycoconjugates found ubiquitously on cell surfaces and within the interstitial matrix of normal tissues (Bishop et al., 2007). These molecules consist of a core protein covalently linked to one or more GAG chains, such as heparan sulfate or chondroitin sulfate, which allow them to interact with a vast array of ligands including growth factors, chemokines, and morphogens (Gandhi & Mancera, 2008). In normal physiological states, they function as essential co-receptors that facilitate signal transduction, regulate blood coagulation through interactions with antithrombin III, and provide structural scaffolding for tissues (Hirsh et al., 2001). While they are frequently studied for their role in sequestering amyloidogenic proteins in neurodegenerative diseases, their non-amyloid forms in healthy tissue are critical for maintaining homeostatic cell-matrix interactions and vascular integrity (Vlodavsky et al., 2012). Pharmacological intervention often targets these molecules using heparin mimetics or heparanase inhibitors to disrupt pathological signaling in cancer, inflammation, and viral entry (Sasisekharan et al., 2002).

Other names

HSPGsGAGsExtracellular matrix proteoglycansHeparan sulfateChondroitin sulfateDermatan sulfateKeratan sulfateHyaluronanNon-amyloid HSPGs

Drugs targeting these molecules typically act as heparin mimetics to competitively inhibit the binding of growth factors and cytokines to endogenous GAGs, or they inhibit enzymes such as heparanase that degrade the HSPG chains, thereby preventing the release of sequestered signaling molecules and maintaining extracellular matrix integrity (Sasisekharan et al., 2002; Vlodavsky et al., 2012).