Role of transforming growth factor-β in the airway inflammation and remodeling in asthma

Transforming growth factor-β (TGF-β) was reported to be increased in asthma in some studies. Accumulation of TGF-β in airway promotes smooth muscle cell mitogenesis and hyperplasia, and induces fibroblast and myofibroblast and smooth muscle proliferation as well as increase in protein synthesis in connective tissue (such as collagen deposition on the reticular basement membrane). The autocrine induction of collagen expression by smooth muscle may contribute to the thickening of the reticular basement membrane, irreversible fibrosis and remodeling seen in the airways in some asthmatics. TGF-β is considered to be a major fibrogenic cytokine. It can increase smooth muscle mass and lead to severe bronchial obstruction in an asthma attack.