Role of the prostaglandin E2 receptor agonists in TGF-β1-induced mesangial cell damage

PGE2 exerts its biological effect through binding to various EP receptors that result inactivation of various signal transduction pathways. It also plays an important role in mice glomerular mesangial cells (MCs) damage induced by transforming growth factor-β1 (TGF-β1); however, the molecular mechanisms remain unknown. In the present study, we tested the efficacy of four selective agonists of PGE2 receptor, EP1A (17-phenyl trinor prostaglandin E2 ethyl amid), EP2A (butaprost), EP3A (sulprostone) and EP4A (cay10580), on mice MCs. Compared with the cAMP produced by TGF-β1, additional pretreatment of EP3A decreased the cAMP level. MCs treated with EP1A and EP3A augmented PGE2, cyclooxygenase-2 (COX-2), membrane-bound PGE synthase 1 (mPGES1), laminin (LN), connective tissue growth factor (CTGF) and cyclin D1 expression stimulated by TGFβ1. EP1A and EP3A increased the number of cells in S+G2/M phase and reduced cells in G0/G1 phase. EP1 and EP3 agonists also strengthened TGFβ1-induced mitogen-activated protein kinase (p38MAPK) and extracellular-signal-regulated kinase 1/2 (ERK1/2) phosphorylation. Whereas MCs treated with EP2A and EP4A weakened PGE2, COX-2, mPGES1, LN, CTGF and cyclin D1 expression stimulated by TGFβ1. EP2A and EP4A decreased the number of cells in S+G2/M phase and increased cells in G0/G1 phase. EP2 and EP4 agonists weakened TGFβ1-induced p38MAPK and ERK1/2 phosphorylation. These findings suggest that PGE2 has an important role in the progression of kidney disease via the EP1/EP3 receptor, whereas EP2 and EP4 receptors are equally important in preserving the progression of chronic kidney failure. Thus, agonists of EP2 and EP4 receptors may provide a basis for treating kidney damage induced by TGF-β1.