MAPK3 and endothelial dysfunction: Mechanistically, stanniocalcin-1(STC1) was identified to be an important paracrine factor secreted by MSCs, which restrains hyperactivation of ERK1/2, thus preventing Drp1-mediated excessive mitochondrial fission, and thereby protecting against hyperglycemia-induced oxidative injury, endothelial inflammation and mitochondrial apoptotic pathway, consequently protecting endothelial dysfunction.