Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.
Eur J Pharmacol. 2012 Aug 15;689(1-3):65-71. doi: 10.1016/j.ejphar.2012.06.008. Epub 2012 Jun 17.
Adipokine leptin reportedly acts on the kidney in pathophysiological states. However, the influence of leptin on renal tubular epithelial cells is still unclear. Gentamicin, a widely used antibiotic for the treatment of bacterial infection, can cause nephrotoxicity. This study aims to investigate the influence of long-term leptin treatment on gentamicin-induced apoptosis in rat renal tubular cells (NRK-52E) and mice. We monitored apoptosis and molecular mechanisms using annexin V/ propidium iodide staining and small interfering RNA transfection. In NRK-52E cells, leptin reduced gentamicin-induced apoptosis at 24h, but significantly increased apoptosis at 48 h. Long-term treatment of leptin decreased Bcl-x(L) expression and increased caspase activity in gentamicin-treated NRK-52E cells. Leptin also increased the expression of cyclooxygenase-2 (COX-2) and its product, prostaglandin E(2) (PGE(2)), in a dose-dependent manner. The COX-2 inhibitor, NS398 (N-[2-(Cyclohexyloxy)-4- nitrophenyl]methanesulfonamide), blocked PGE(2) augmentation and the pro-apoptotic effects of leptin. The addition of PGE(2) recovered the pro-apoptotic effect of leptin in NS398-treated NRK-52E cells. In a mouse animal model, a 10 day leptin treatment significantly increased gentamicin-induced apoptotic cells in proximal tubules. NS398 treatment inhibited this in vivo pro-apoptotic effect of leptin. Results reveal that long-term elevation of leptin induces COX-2-mediated PGE(2) augmentation in renal tubular cells, and then increases these cells' susceptibility to gentamicin-induced apoptosis.
据报道，脂肪细胞因子瘦素在病理生理状态下作用于肾脏。然而，瘦素对肾小管上皮细胞的影响尚不清楚。庆大霉素是一种广泛用于治疗细菌感染的抗生素，可引起肾毒性。本研究旨在探讨长期瘦素治疗对庆大霉素诱导的大鼠肾小管细胞（NRK-52E）和小鼠肾小管细胞凋亡的影响。我们使用 Annexin V/碘化丙啶染色和小干扰 RNA 转染来监测细胞凋亡和分子机制。在 NRK-52E 细胞中，瘦素在 24 小时降低了庆大霉素诱导的细胞凋亡，但在 48 小时显著增加了细胞凋亡。长期瘦素处理降低了庆大霉素处理的 NRK-52E 细胞中 Bcl-x(L)的表达并增加了半胱天冬酶的活性。瘦素还以剂量依赖的方式增加了环氧化酶-2（COX-2）及其产物前列腺素 E2（PGE2）的表达。COX-2 抑制剂 NS398（N-[2-（环己氧基）-4-硝基苯基]甲磺酰胺）阻断了 PGE2 的增加和瘦素的促凋亡作用。PGE2 的添加恢复了 NS398 处理的 NRK-52E 细胞中瘦素的促凋亡作用。在小鼠动物模型中，10 天的瘦素处理显著增加了庆大霉素诱导的近端肾小管细胞凋亡。NS398 处理抑制了这种体内瘦素的促凋亡作用。结果表明，长期瘦素升高诱导肾小管细胞中 COX-2 介导的 PGE2 增加，然后增加这些细胞对庆大霉素诱导的凋亡的敏感性。
