Decorin (DCN) belongs to the small leucine-rich proteoglycan (SLRP) family. Decorin is member of the class 1 of SLRP family with relative molecular mass of core protein of 40 kDa and with an attached glycosaminoglycan chain consisting of either chondroitin sulfate (CS) or dermatan sulfate (DS) in the range of 120 to 180 kDa. It has a four-domain structure and domain II contains glycosaminoglycan attachment site and domain III contains 10 leucine-rich repeats (LRR) which are involved in protein-protein interaction. Decorin is secreted mainly by mesenchymal cells and plays a key role in the regulation of extracellular matrix assembly by binding to several components. Decorin has a high affinity binding site for collagen at LRRs 4–6 and after interaction with collagen affects fibril formation and stabilizes them. These effects may explain the phenotype of decorin null mice characterized by abnormal skin fragility and loosely packed collagen fibers. Binding of decorin with fibronectin and thrombospondin modulates cell adhesion and migration. In addition, decorin has multiple non-structural functions and interacts with a number of biological molecules such as growth factors (TGF-β, FGF-2, IGF-1, TNF-α), the complement component C1q and epidermal growth factor receptor (EGFR). These interactions are consistent with decorin´s involvement in diverse processes such as tumor growth and metastasis, angiogenesis, renal and pulmonary fibrosis, muscular dystrophy, wound healing and myocardial infarction. Decorin has been shown to have anti-tumorigenic properties in an experimental murine tumor model and is capable of suppressing the growth of various tumor cell lines. Decorin expression in adipose tissue is markedly upregulated in the obese state and may therefore play a role in adipose tissue homeostasis or in pathophysiology associated with obesity and type 2 diabetes. There is evidence from in vitro and in vivo animal models as well as humans to suggest an important role of decorin in attenuating progression of atherosclerosis. Decorin distribution in different blood vessels has been shown to inversely correlate with the tendency to develop atherosclerosis. A recent study described that plasma decorin levels are decreased in patients with acute ischemic stroke and this decorin reduction may be associated with increased risk for ischemic stroke. Other findings indicate that the estrogen-independent anti-proliferative effects of decorin on endometriotic epithelial cells and endometrial stromal cells may contribute to the effectiveness against endometriosis.
- References to Decorin (Bone proteoglycan II, PG-S2, PG40, DCN, SLRR1B)