Urotensin II exerts antiapoptotic effect on NRK-52E cells through prostacyclin-mediated peroxisome proliferator-activated receptor alpha and Akt activation

Celecoxib has Preventive and Therapeutic Benefits against Nephrotoxicity Caused by Gentamicin in Mice

It's crucial to comprehend the impact of oxidative stress and pro-inflammatory cytokines in the gentamicin-induced kidney injury mechanism. Celecoxib was administered orally either before or after intraperitoneal therapy with gentamicin in mice. The serum levels of creatinine (SCr), blood urea nitrogen (BUN), IL-6, and TNF-α were measured by ELISA test, as well as the levels of the kidney tissue malondialdehyde (MDA), and glutathione (GSH) were also estimated spectrophotometrically. The renal expression of nuclear factor-κB (NF-κB), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and cyclooxygenase 2 (COX-2) mRNAs were evaluated by qPCR. Histopathological evaluation and Immunohistochemical examination of kidney NF-κB, IL-6, and COX-2 were also, performed. Celecoxib successfully prevented gentamicin-induced kidney damage as indicated by reducing blood BUN, SCr, and tissue MDA levels and increasing renal tissue GSH levels as well as lowering the blood IL-6 and TNF-α in comparison to mice received gentamicin. Furthermore, celecoxib has inhibited COX-2, NF-κB, IL-6, and TNF-α expression in the renal tissue. It is noteworthy that celecoxib therapy after gentamicin administration brought about substantially the same results as celecoxib treatment before gentamicin injection in mice. Our results showed the role of celecoxib as a therapeutic tool for gentamicin-induced nephrotoxicity as well as raised its beneficial prophylactic role in this medical challenge by attenuating oxidative stress and inflammation.

Effect of cell cycle synchronization on cadmium-induced apoptosis and necrosis in NRK-52E cells

Heavy metal pollution is a problem that cannot be ignored. Due to the prevalence of cadmium in the environment and its harmful effects on humans, cadmium pollution has become a research hotspot recently. The mechanism of cadmium-induced toxicity has also drawn much attention and most studies have been conducted using whole cells, but the toxicological mechanism of cadmium remains unclear. In this study, we aimed to obtain NRK-52E cells at different growth stages by various methods and analyze the differences in cadmium toxicity. The results show that the cadmium sensitivity of cells in each phase was different and the late apoptotic rate was increased significantly after 5 µM Cd treatment. In addition, cadmium easily induces apoptosis of G0- and S-phase cells, as well as necrosis of S- and M-phase cells, but has no significant effect on G1-phase cells. Overall, we first explored the differences in the effects of cadmium on NRK-52E cells at various growth phases. Besides, the findings of this study might provide a theoretical basis for further exploration of the toxicological mechanism of cadmium.Abbreviations Cd: cadmium; CDK: cyclin-dependent kinases; DAPI 2-(4-amidinophenyl)-1H-indole-6-carboxamidine; TBST: Tris-buffered saline with Tween-20; PI: propidium iodide; DMEM: Dulbecco's Modified Eagle Medium; BCA: bicinchoninic acid.

Iloprost supports early development of in vitro-produced porcine embryos through activation of the phosphatidylinositol 3-kinase/AKT signalling pathway

Despite evidence of the presence of prostaglandin (PG) I₂ in mammalian oviducts, its role in early development of in vitro-produced (IVP) embryos is largely unknown. Thus, in the present study we examined the effects of iloprost, a PGI₂ analogue, on the in vitro developmental competence of early porcine embryos and the underlying mechanism(s). To examine the effects of iloprost on the development rate of IVF embryos, iloprost was added to the in vitro culture (IVC) medium and cultured for 6 days. Supplementation of the IVC medium with iloprost significantly improved developmental parameters, such as blastocyst formation rate, the trophectoderm:inner cell mass ratio and cell survival in IVF and parthenogenetically activated (PA) embryos. In addition, post-blastulation development into the expanded blastocyst stage was improved in iloprost-treated groups compared with controls. Interestingly, the phosphatidylinositol 3-kinase (PI3K)/AKT signalling pathway was significantly activated by iloprost supplementation in a concentration-dependent manner (10-1000nM), and the beneficial effects of iloprost on the early development of porcine IVF and PA embryos was completely ablated by treatment with 2.5μM wortmannin, a PI3K/AKT signalling inhibitor. Importantly, expression of the PI3K/AKT signalling pathway was significantly reduced in somatic cell nuclear transfer (SCNT) compared with IVF embryos, and iloprost supported the early development of SCNT embryos, as was the case for IVF and PA embryos, suggesting a consistent effect of iloprost on the IVC of IVP porcine embryos. Together, these results indicate that iloprost can be a useful IVC supplement for production of IVP early porcine embryos with high developmental competence.

Prostaglandins in the pathogenesis of kidney diseases

Prostaglandins (PGs) are important lipid mediators produced from arachidonic acid via the sequential catalyzation of cyclooxygenases (COXs) and specific prostaglandin synthases. There are five subtypes of PGs, namely PGE2, PGI2, PGD2, PGF2α, and thromboxane A2 (TXA2). PGs exert distinct roles by combining to a diverse family of membrane-spanning G protein-coupled prostanoid receptors. The distribution of these PGs, their specific synthases and receptors vary a lot in the kidney. This review summarized the recent findings of PGs together with the COXs and their specific synthases and receptors in regulating renal function and highlighted the insights into their roles in the pathogenesis of various kidney diseases.

Peroxisome Proliferator-Activated Receptor α Protects Renal Tubular Cells from Gentamicin-Induced Apoptosis via Upregulating Na+/H+ Exchanger NHE1

Peroxisome proliferator-activated receptor (PPAR)-α is a transcription factor that has been reported to inhibit gentamicin-induced apoptosis in renal tubular cells. However, the antiapoptotic mechanism of PPARα is still unknown. In this study, we found that PPARα overexpression induced Na⁺/H⁺ exchanger-1 (NHE1) expression in the rat renal tubular cells NRK-52E. Beraprost, a PPARα ligand, also increased NHE1 expression in the renal tubules in normal mice, but not in PPARα knockout mice. Chromatin immunoprecipitation assays revealed that two PPARα binding elements were located in the rat NHE1 promoter region. Na⁺/H⁺ exchanger activity also increased in the PPARα-overexpressed cells. Flow cytometry showed that the PPARα-overexpressed cells were resistant to apoptosis-induced shrinkage. Cariporide, a selective NHE1 inhibitor, inhibited the antiapoptotic effect of PPARα in the gentamicin-treated cells. The interaction between NHE1 and ezrin/radixin/moesin (ERM) and between ERM and phosphatidylinositol 4,5-bisphosphate in the PPARα-overexpressed cells was more than in the control cells. ERM short interfering RNA (siRNA) transfection inhibited the PPARα-induced antiapoptotic effect. PPARα overexpression also increased the phosphoinositide 3-kinase (PI3K) expression, which is dependent on NHE1 activity. Increased PI3K further increased the phosphorylation of the prosurvival kinase Akt in the PPARα-overexpressed cells. Wortmannin, a PI3K inhibitor, inhibited PPARα-induced Akt activity and the antiapoptotic effect. We conclude that PPARα induces NHE1 expression and then recruits ERM to promote PI3K/Akt-mediated cell survival in renal tubular cells. The application of PPARα activation reduces the nephrotoxicity of gentamicin and may expand the clinical use of gentamicin.