TGF- β 1

TGF-beta 1 is a member of the TGF beta superfamily, which includes at least five other isoforms. It is synthesized as a 390 amino acid glycoprotein and contains a 29 amino acid signal sequence and a 249 amino acid latency associated pro-peptide sequence. TGF-beta 1 is a pleotropic cytokine that regulates various functions, such proliferation and differentiation, of immune and non-immune somatic cells via paracrine and autocrine mechanisms. It is a potent cell growth inhibitor of fibroblasts, hepatocytes, keratinocytes, and endothelial and neuronal cells. For example, TGF-beta 1 can impair the immune response by deactivating macrophages and promoting the regulation of T cells, and it plays a role in T-lymphocyte and natural killer cell growth inhibition, via down-regulating IL-1 and IL-2 mediated proliferative signals. Furthermore, TGF-beta 1 downregulates hematopoietic progenitor cell growth and megakaryocytopoiehsis, and is involved in extracellular matrix (ECM) degradation/ remodeling via inducing ECM protein expression, such as integrins, collagen and fibronectin. It also contributes to bone formation, bone remodeling and participates in regulating chemotaxis and differentiation of osteoblasts. The abnormal activation or inhibition of TGF-beta regulated processes is implicated in many diseases including cancer, fibrosis and inflammatory disorders such as rheumatoid arthritis and nephritis. TGF-beta 1 also exhibits cardioprotective properties and has been suggested to be an important regulator of contractile function of the heart.