Molecular mechanism of transforming growth factor-β on promoting corneal stroma scarring

Transforming growth factor-β(TGF-β) plays a key role during corneal stroma scarring.It is a critical regulator in abnormal deposition of extracellular matrix (ECM) and construction of collagen fibers.TGF-β is a family cytokines secreted by a variety of cells.It has multiple effects only when it is activated.The major signaling pathway of TGF-β is Smad, which is activated by the binding of TGF-β and its receptors.TGF-β stimulates the synthesis and secretion of collagen and proteoglycan, which results in disbalance of synthesis and degradation of ECM.The mechanism of TGF-β on promoting corneal fibrosis includes upregulating connective tissue growth factor (CTGF), downregulating keratin sulfate proteoglycans(KSPGs) and inhibiting the degradation of ECM by regulating matrix metalloproteinases(MMPs). Recently, TGF-β has been a promoting growth factor of scar-free wound healing because of its extensive biological effects.This review summarized biological characteristics of TGF-β, its receptors and Smads signal pathway and the molecular mechanism that accelerates corneal stroma scarring. Key words: Transforming growth factor-β; Corneal stroma; Scarring; Molecular mechanism