Sabbatini Massimo, Santillo Mariarosaria, Pisani Antonio, Paternò Roberto, Uccello Francesco, Serù Rosalba, Matrone Gianfranco, Spagnuolo Gianrico, Andreucci Michele, Serio Vittorio, Esposito Pasquale, Cianciaruso Bruno, Fuiano Giorgio, Avvedimento Enrico V
University Magna Graecia of Catanzaro, Italy
Am J Physiol Renal Physiol. 2006 Jun;290(6):F1408-15. doi: 10.1152/ajprenal.00304.2005. Epub 2006 Jan 24.
The small GTPase p21 Ras and its downstream effectors play a central role in the control of cell survival and apoptosis. We studied the effects of Ras/ERK1/2 signaling inhibition on oxidative damage in cultured renal and endothelial cells and on renal ischemia-reperfusion injury in the rat. Primary human renal tubular and human endothelial ECV304 cells underwent significant cell death when subjected to oxidative stress. This type of stress induced robustly ERK1/2 and phosphoinositide 3-kinase (PI3-kinase) signaling. Inhibition of Ras/ERK1/2 with a farnesyl transferase inhibitor, chaetomellic acid A (S-FTI), or with PD-98059, an inhibitor of MEK, a kinase upstream ERK1/2, significantly reduced the fraction of dead cells. The inhibitor of the PI3-kinase/Akt pathway, LY-294002, failed to exert a protective effect. We have translated these data in a rat model of renal ischemic injury in vivo. In uninephrectomized animals, anesthetized with pentobarbital sodium (Nembutal, 50 mg/kg i.p.), 24 h after an acute ischemic renal insult (45-min occlusion of left renal artery) a significant fraction of kidney cells succumbed to cell death resulting in renal failure [glomerular filtration rate (GFR) 0.17 +/- 0.1 vs. 0.90 +/- 0.4 ml x min(-1) x 100 g body wt(-1) in normal rats]. Rats treated with S-FTI maintained the renal function (GFR 0.50 +/- 0.1 ml x min(-1) x 100 g body wt(-1)), and the kidneys showed a significant reduction of tubular necrosis. Reduction of ischemic damage in kidney and tubular cells paralleled Ha-Ras inhibition, assayed by cytosolic translocation of the protein. These data demonstrate that inhibition of farnesylation and consequently of Ras/ERK1/2 signaling significantly reduces acute postischemic renal injury.
小GTP酶p21 Ras及其下游效应物在细胞存活和凋亡的调控中起核心作用。我们研究了Ras/ERK1/2信号通路抑制对培养的肾细胞和内皮细胞氧化损伤以及对大鼠肾缺血再灌注损伤的影响。原代人肾小管细胞和人内皮ECV304细胞在受到氧化应激时会发生显著的细胞死亡。这种应激强烈诱导ERK1/2和磷酸肌醇3激酶（PI3激酶）信号通路。用法尼基转移酶抑制剂chaetomellic acid A（S-FTI）或用MEK（ERK1/2上游的一种激酶）抑制剂PD-98059抑制Ras/ERK1/2，可显著降低死亡细胞的比例。PI3激酶/Akt通路抑制剂LY-294002未能发挥保护作用。我们已将这些数据转化到体内肾缺血损伤的大鼠模型中。在单侧肾切除的动物中，用戊巴比妥钠（Nembutal，50 mg/kg腹腔注射）麻醉，急性肾缺血损伤（左肾动脉阻断45分钟）24小时后，相当一部分肾细胞死于细胞死亡，导致肾衰竭[肾小球滤过率（GFR）为0.17±0.1 vs.正常大鼠的0.90±0.4 ml·min⁻¹·100 g体重⁻¹]。用S-FTI治疗的大鼠维持了肾功能（GFR为0.50±0.1 ml·min⁻¹·100 g体重⁻¹），且肾脏显示肾小管坏死显著减少。肾脏和肾小管细胞缺血损伤的减轻与通过蛋白质胞质转位测定的Ha-Ras抑制平行。这些数据表明，抑制法尼基化以及由此抑制Ras/ERK1/2信号通路可显著减轻急性缺血后肾损伤。
