Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
Kidney Int. 2012 Jul;82(1):45-52. doi: 10.1038/ki.2012.43. Epub 2012 Mar 14.
To determine the role of epidermal growth factor receptor (EGFR) activation in renal functional and structural recovery from acute kidney injury (AKI), we generated mice with a specific EGFR deletion in the renal proximal tubule (EGFR(ptKO)). Ischemia-reperfusion injury markedly activated EGFR in control littermate mice; however, this was inhibited in either the knockout or wild-type mice given erlotinib, a specific EGFR tyrosine kinase inhibitor. Blood urea nitrogen and serum creatinine increased to a comparable level in EGFR(ptKO) and control mice 24 h after reperfusion, but the subsequent rate of renal function recovery was markedly slowed in the knockout mice. Twenty-four hours after reperfusion, both the knockout and the inhibitor-treated mice had a similar degree of histologic renal injury as control mice, but at day 6 there was minimal evidence of injury in the control mice while both EGFR(ptKO) and erlotinib-treated mice still had persistent proximal tubule dilation, epithelial simplification, and cast formation. Additionally, renal cell proliferation was delayed due to decreased ERK and Akt signaling. Thus, our studies provide both genetic and pharmacologic evidence that proximal tubule EGFR activation plays an important role in the recovery phase after acute kidney injury.
为了确定表皮生长因子受体 (EGFR) 激活在急性肾损伤 (AKI) 后肾功能和结构恢复中的作用,我们生成了近端肾小管特异性 EGFR 缺失 (EGFR(ptKO)) 的小鼠。缺血再灌注损伤使对照同窝仔鼠的 EGFR 明显激活;然而,在给予厄洛替尼(一种特异性 EGFR 酪氨酸激酶抑制剂)的敲除或野生型小鼠中,这种激活受到抑制。再灌注后 24 小时,EGFR(ptKO)和对照小鼠的血尿素氮和血清肌酐均升高至相当水平,但随后的肾功能恢复速度在敲除小鼠中明显减慢。再灌注 24 小时后,敲除和抑制剂处理的小鼠与对照小鼠的肾组织损伤程度相似,但在第 6 天,对照小鼠几乎没有损伤证据,而 EGFR(ptKO)和厄洛替尼处理的小鼠仍存在持续的近端肾小管扩张、上皮简单化和管型形成。此外,由于 ERK 和 Akt 信号转导减少,肾细胞增殖延迟。因此,我们的研究提供了遗传和药理学证据,表明近端肾小管 EGFR 激活在急性肾损伤后的恢复阶段发挥重要作用。