Department of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Am J Physiol Renal Physiol. 2020 Mar 1;318(3):F793-F803. doi: 10.1152/ajprenal.00367.2019. Epub 2020 Feb 10.
Acute kidney injury has a high global morbidity associated with an increased risk of death and chronic kidney disease. Renal tubular epithelial cell regeneration following injury may be a decisive factor in renal repair or the progression of acute kidney injury to chronic kidney disease, but the underlying mechanism of abnormal renal tubular repair remains unclear. In the present study, we investigated the role of heterotrimeric G stimulatory protein α-subunit (Gsa) in renal tubular epithelial cell regeneration. We generated renal tubule epithelium-specific Gsa knockout (Gsa) mice to show the essential role of Gsa in renal tubular epithelial cell regeneration in two AKI models: acute aristolochic acid nephropathy (AAN) and unilateral ischemia-reperfusion injury (UIRI). Gsa mice developed more severe renal impairment after AAN and UIRI, higher serum creatinine levels, and more substantial tubular necrosis than wild-type mice. More importantly, Gsa inactivation impaired renal tubular epithelial cell proliferation by reducing bromodeoxyuridine cell numbers in the AAN model and inhibiting cyclin-dependent kinase 2/cyclin E1 expression in the UIRI model. This reduced proliferation was further supported in vitro with Gsa-targeting siRNA. Downregulation of Gsa inhibited tubular epithelial cell proliferation in HK-2 and mIMCD-3 cells. Furthermore, Gsa downregulation inhibited cyclin-dependent kinase 2/cyclin E1 expression, which was dependent on the Raf-MEK-ERK signaling pathway. In conclusion, Gsa is required for tubular epithelial cell regeneration during kidney repair after AKI. Loss of Gsa impairs renal tubular epithelial cell regeneration by blocking the Raf-MEK-ERK pathway.
急性肾损伤具有很高的全球发病率，与死亡风险增加和慢性肾脏病有关。损伤后肾小管上皮细胞的再生可能是肾脏修复或急性肾损伤向慢性肾脏病进展的决定性因素，但异常肾小管修复的潜在机制尚不清楚。在本研究中，我们研究了异三聚体 G 刺激蛋白α亚基（Gsa）在肾小管上皮细胞再生中的作用。我们生成了肾小管上皮细胞特异性 Gsa 敲除（Gsa）小鼠，以显示 Gsa 在两种 AKI 模型（急性马兜铃酸肾病（AAN）和单侧缺血再灌注损伤（UIRI））中对肾小管上皮细胞再生的重要作用。与野生型小鼠相比，Gsa 小鼠在 AAN 和 UIRI 后表现出更严重的肾功能损害、更高的血清肌酐水平和更严重的肾小管坏死。更重要的是，Gsa 失活通过减少 AAN 模型中的溴脱氧尿苷细胞数量和抑制 UIRI 模型中的细胞周期蛋白依赖性激酶 2/细胞周期蛋白 E1 表达来损害肾小管上皮细胞增殖。这一减少的增殖在体外使用 Gsa 靶向 siRNA 得到了进一步支持。Gsa 下调抑制了 HK-2 和 mIMCD-3 细胞中的管状上皮细胞增殖。此外，Gsa 下调抑制了细胞周期蛋白依赖性激酶 2/细胞周期蛋白 E1 的表达，这依赖于 Raf-MEK-ERK 信号通路。总之，Gsa 是 AKI 后肾脏修复期间肾小管上皮细胞再生所必需的。Gsa 的缺失通过阻断 Raf-MEK-ERK 通路来损害肾小管上皮细胞的再生。
