MAPK8 and diabetes mellitus: Growth arrest and DNA-damage-inducible 45 beta (GADD45B) participates in mediating cell cycle arrest, DNA damage repair and apoptosis in response to cell injury and has an effect in diabetes-induced renal tubular epithelial-mesenchymal transition (EMT) and apoptosis via the p38 MAPK and JNK pathways, which may be an important mechanism of diabetic kidney injury [34, 35].