Division of Renal Diseases and Hypertension, University of Colorado at Denver, Aurora, CO, USA.
Electron Microscopy Center, University of Colorado at Denver, Aurora, CO, USA.
Cell Death Dis. 2021 Mar 5;12(3):248. doi: 10.1038/s41419-021-03518-w.
Many surgical models are used to study kidney and other diseases in mice, yet the effects of the surgical procedure itself on the kidney and other tissues have not been elucidated. In the present study, we found that both sham surgery and unilateral nephrectomy (UNX), which is used as a model of renal compensatory hypertrophy, in mice resulted in increased mammalian target of rapamycin complex 1/2 (mTORC1/2) in the remaining kidney. mTORC1 is known to regulate lysosomal biogenesis and autophagy. Genes associated with lysosomal biogenesis and function were decreased in sham surgery and UNX kidneys. In both sham surgery and UNX, there was suppressed autophagic flux in the kidney as indicated by the lack of an increase in LC3-II or autophagosomes seen on immunoblot, IF and EM after bafilomycin A1 administration and a concomitant increase in p62, a marker of autophagic cargo. There was a massive increase in pro-inflammatory cytokines, which are known to activate ERK1/2, in the serum after sham surgery and UNX. There was a large increase in ERK1/2 in sham surgery and UNX kidneys, which was blocked by the MEK1/2 inhibitor, trametinib. Trametinib also resulted in a significant decrease in p62. In summary, there was an intense systemic inflammatory response, an ERK-mediated increase in p62 and suppressed autophagic flux in the kidney after sham surgery and UNX. It is important that researchers are aware that changes in systemic pro-inflammatory cytokines, ERK1/2 and autophagy can be caused by sham surgery as well as the kidney injury/disease itself.
许多外科模型被用于研究小鼠的肾脏和其他疾病，但手术本身对肾脏和其他组织的影响尚未阐明。在本研究中，我们发现假手术和单侧肾切除术（UNX）都会导致小鼠剩余肾脏中哺乳动物雷帕霉素靶蛋白复合物 1/2（mTORC1/2）的增加。mTORC1 已知可调节溶酶体生物发生和自噬。与溶酶体生物发生和功能相关的基因在假手术和 UNX 肾脏中减少。在假手术和 UNX 中，肾脏中的自噬流被抑制，这表明在用巴弗洛霉素 A1 处理后，LC3-II 或自噬体未见增加，免疫印迹、IF 和 EM 也未见增加，而 p62（自噬货物的标志物）增加。在假手术和 UNX 后，血清中促炎细胞因子大量增加，已知这些细胞因子可激活 ERK1/2。假手术和 UNX 肾脏中 ERK1/2 的大量增加被 MEK1/2 抑制剂 trametinib 阻断。trametinib 还导致 p62 显著减少。总之，假手术和 UNX 后，肾脏中存在强烈的全身炎症反应、ERK 介导的 p62 增加和自噬流抑制。研究人员应该意识到，系统促炎细胞因子、ERK1/2 和自噬的变化不仅可以由肾损伤/疾病本身引起，也可以由假手术引起。
