MAPK3 and Hyperglycemia: Similarly, under the stimulation of hyperglycemia, renal tubular epithelial cells developed hypertrophy and increased the expression of TGF-β, while the application of ERK1/2 pathway inhibitor PD98059 could significantly inhibit the hyperglucose-induced hyperexpression of TGF-β and extracellular matrix (ECM) in mesangial cells and tubular epithelial cells (Xu and Kyriakis, 2003).