FN1 and diabetic kidney disease: Diabetic nephropathy (DN) is a severe microvascular complication of diabetes that is characterized by sequential pathology, including renal hypertrophy and basement membrane thickening at the early stages and extracellular matrix (ECM) (such as fibronectin (FN) and collagen accumulation), glomerulosclerosis, and interstitial fibrosis at the latter stages, ultimately leading to renal function loss and end-stage renal diseases [1,2].