ABSTRACT
Transforming growth factor ß1 (TGF-ß1) plays a central role in chronic kidney diseases. TGF-ß1 induction causes podocyte injury, which results in proteinuria and renal failure. However, the effect of the prostaglandin E2 /E-prostanoid receptor (EP2) on TGF-ß1-induced podocyte injury remains unknown. Previous studies have shown that phosphoinositide 3-OH kinase (PI3K)/Akt is widespread in cells, and is vital for the regulation of cell proliferation, differentiation, apoptosis and metabolism. In this study, we cultured immortalized mouse podocytes in vitro in different groups: control group; TGF-ß1 (5ng/ml) group; EP2 agonist Butaprost treatment (10-7, 10-6, or 10-5mol/L) +TGF-ß1 group; EP2 antagonist AH6809 treatment (10-7, 10-6, or 10-5mol / L) + TGF-ß1 group. We found that compared with the control group, proliferation of podocytes in the TGF-ß1 group significantly decreased and apoptosis increased. Expression of cAMP decreased, whereas PGE2 increased. Meanwhile, expressions of nephrin, podocin and CD2AP mRNA and protein were dramatically downregulated, activated caspase-3 was increased, and activated PI3K/Akt activity were depressed. Butaprost intervention promoted podocyte proliferation with reduced apoptosis. Conversely, AH6809 intervention led to opposite results (P<0.05). Our findings suggested that EP2 agonist protects podocytes by increasing expression of cAMP, which creates feedback of inhibiting PGE2 expression. This causes the interaction of nephrin, podocin and CD2AP resulting the inhibition of apoptosis induced by activation of the PI3K / Akt signaling pathway.
Subject(s)
Acute Kidney Injury/prevention & control , Phosphatidylinositol 3-Kinases/metabolism , Podocytes/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Receptors, Prostaglandin E, EP2 Subtype/metabolism , Signal Transduction , Transforming Growth Factor beta1/metabolism , Acute Kidney Injury/genetics , Acute Kidney Injury/metabolism , Acute Kidney Injury/pathology , Adaptor Proteins, Signal Transducing/biosynthesis , Adaptor Proteins, Signal Transducing/genetics , Animals , Apoptosis/drug effects , Cytoskeletal Proteins/biosynthesis , Cytoskeletal Proteins/genetics , Dinoprostone/biosynthesis , Gene Expression Regulation/drug effects , Mice , Phosphatidylinositol 3-Kinases/genetics , Podocytes/pathology , Proto-Oncogene Proteins c-akt/genetics , Receptors, Prostaglandin E, EP2 Subtype/antagonists & inhibitors , Receptors, Prostaglandin E, EP2 Subtype/genetics , Transforming Growth Factor beta1/genetics , Xanthones/pharmacologyABSTRACT
Cardiovascular and renal inflammation induced by Aldosterone (Aldo) plays a pivotal role in the pathogenesis of hypertension and renal fibrosis. GSK-3ß contributes to inflammatory cardiovascular and renal diseases, but its role in Aldo-induced hypertension, and renal damage is not clear. In the present study, rats were treated with Aldo combined with SB-216763 (a GSK-3ß inhibitor) for 4 weeks. Hemodynamic, cardiac, and renal parameters were assayed at the indicated time. Here we found that rats treated with Aldo presented cardiac and renal hypertrophy and dysfunction. Cardiac and renal expression levels of molecular markers attesting inflammation and fibrosis were increased by Aldo infusion, whereas the treatment of SB-216763 reversed these alterations. SB-216763 suppressed cardiac and renal inflammatory cytokines levels (TNF-a, IL-1ß, and MCP-1). Meanwhile, SB-216763 increased the protein levels of LC3-II in the cardiorenal tissues as well as p62 degradation, indicating that SB-216763 induced autophagy activation in cardiac, and renal tissues. Importantly, inhibition of autophagy by 3-MA attenuated the role of SB-216763 in inhibiting perivascular fibrosis, and tubulointerstitial injury. These data suggest that SB-216763 protected against Aldo-induced cardiac and renal injury by activating autophagy, and might be a therapeutic option for salt-sensitive hypertension and renal fibrosis.
