FN1 and renal fibrosis: The main pathological feature of DN is glomerular sclerosis, which is manifested by the hypertrophy of glomerular mesangial cells, and overexpression of ECM, including collagen, fibronectin and laminin; these proteins are secreted outside the mesangial cells and deposited in the glomerulus, leading to glomerular sclerosis, which eventually develops into renal fibrosis (Hua et al.