Prostaglandin E2 promotes cell survival of glomerular epithelial cells via the EP4 receptor

L Aoudjit, A Potapov, T Takano - American Journal of …, 2006 - journals.physiology.org
L Aoudjit, A Potapov, T Takano
American Journal of Physiology-Renal Physiology, 2006journals.physiology.org
Visceral glomerular epithelial cells (GEC) are crucial for glomerular permselectivity and
structural integrity in the kidney. The current study addressed the role of cyclooxygenase
(COX)-2 and its product prostaglandin (PG) E2 in GEC survival. We generated a subclone of
cultured rat GEC, which overexpress COX-2 in an inducible manner. When COX-2 was
induced, GEC survived better in serum-deprived conditions. Induction of COX-2 was
correlated with increased PGE2 generation, increased activation of extracellular signal …
Visceral glomerular epithelial cells (GEC) are crucial for glomerular permselectivity and structural integrity in the kidney. The current study addressed the role of cyclooxygenase (COX)-2 and its product prostaglandin (PG) E2 in GEC survival. We generated a subclone of cultured rat GEC, which overexpress COX-2 in an inducible manner. When COX-2 was induced, GEC survived better in serum-deprived conditions. Induction of COX-2 was correlated with increased PGE2 generation, increased activation of extracellular signal-regulated kinase, decreased apoptosis, and increased cell proliferation. Rat GEC abundantly expressed the EP4 isoform of PGE2 receptor. Induction of COX-2 and addition of exogenous PGE2 both lead to decreased serum deprivation-induced apoptosis, which was accompanied by activation of the survival kinase Akt. Anti-apoptotic effect of COX-2 induction was reversed by the specific inhibitor of the EP4 receptor, L-161982. PGE2 also inhibited puromycin aminonucleoside-induced GEC apoptosis in vitro. Acute puromycin aminonucleoside nephrosis (PAN) is a rat model of GEC injury and proteinuria. In rats with PAN, glomerular apoptosis, quantified as caspase-3 activity, as well as urinary protein excretion were significantly increased, compared with control rats. Administration of L-161982 in rats with PAN further exacerbated caspase-3 activation and proteinuria. Thus COX-2 and its product PGE2 may have anti-apoptotic/protective effect on GEC via the EP4 receptor of PGE2.
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