ATG5-mediated autophagy suppresses NF-κB signaling to limit epithelial inflammatory response to kidney injury
ATG5-mediated autophagy suppresses NF-κB signaling to limit epithelial inflammatory response to kidney injury
复制标题
ATG5 介导的自噬抑制 NF-kappa B 信号传导，限制上皮炎症反应对肾损伤的影响
DOI：
10.1038/s41419-019-1483-7
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发表时间：
2019-03-15
影响因子：
9
通讯作者：
Mao, Haiping
中科院分区：
文献类型：
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作者：
Peng, Xuan;Wang, Yating;Mao, Haiping
肾损伤后G2/M期阻滞的近端肾小管上皮细胞（TEC）与细胞因子产生增加有关。近端TEC中的ATG5介导的自噬最近已被证明可防止G2/M细胞周期停滞和肾纤维化。然而，自噬在调节由受损TEC引起的炎症反应中的作用在很大程度上仍然未知。在本研究中，我们研究了在肾损伤过程中，ATG5是否作为近端TEC的先天性免疫抑制因子。使用单侧输尿管梗阻模型在近端小管特异性自噬缺陷小鼠，我们证明，消融上皮细胞ATG 5基因显着损害自噬，导致增强核因子-κ B（NF-κ B B）的激活，巨噬细胞和淋巴细胞浸润，并在梗阻的肾脏促炎细胞因子的生产，与野生型小鼠相比。在血管紧张素II（Ang II）刺激后，在培养的HK-2细胞或ATG5缺陷的原代近端TEC中，ATG5的siRNA沉默产生比其对照细胞更多的细胞因子，包括IL-1 β、IL-6和TNF-α。在HK-2细胞中，过度表达的ATG5，而不是自噬无能的ATG5突变体K130R，对Ang II诱导的炎症反应具有抵抗性。免疫荧光检测表明ATG5和p65共定位于细胞核和细胞质中，并且在HEK-293T细胞提取物的免疫沉淀检测中证实了它们的相互作用。内源性ATG5的基因下调增加了Ang II诱导的p65磷酸化和核转位以及NF-κ B的转录活性，而过表达的ATG5，而不是ATG5突变体K130 R，阻碍了NF-κ B信号转导的激活，表明ATG5的自噬依赖性抗炎作用。此外，自噬的药理学操作在体内和体外都产生了类似的结果。此外，NF-κ B B核转位的特异性抑制剂JSH-23在ATG5 siRNA处理的细胞中拯救了Ang II驱动的IL-1 β产生，并降低了G2/M期细胞的比例。总之，肾小管中的ATG 5介导的自噬靶向NF-κ B信号传导以保护免受肾脏炎症。
G2/M-arrested proximal tubular epithelial cells (TECs) after renal injury are linked to increased cytokines production. ATG5-mediated autophagy in proximal TECs has recently been shown to protect against G2/M cell cycle arrest and renal fibrosis. However, the impacts of autophagy in regulating inflammatorily response mounted by injured TECs remains largely unknown. In the present study, we investigated whether ATG5 acts as an innate immune suppressor in proximal TECs during kidney injury. Using the unilateral ureteric obstruction model in proximal tubule-specific autophagy-deficient mice, we demonstrated that ablation of epithelial ATG5 genes markedly impaired autophagy, resulting in enhanced nuclear factor kappa B (NF-kappa B) activation, macrophage and lymphocyte infiltration, and proinflammatory cytokines production in obstructed kidneys, as compared with wild-type mice. Following stimulation with angiotensin II (Ang II), siRNA silencing of ATG5 in cultured HK-2 cells or ATG5-deficient primary proximal TECs produced more cytokines, including IL-1 beta, IL-6, and TNF-alpha than did their control cells. Overexpressed ATG5, but not the autophagy-incompetent ATG5 mutant K130R in HK-2 cells, rendered resistant to Ang II-induced inflammatory response. Immunofluorescence assay indicated that ATG5 and p65 colocalized in the nucleus and cytoplasm, and their interaction was verified in immunoprecipitation assay from HEK-293T cell extracts. Genetic downregulation of endogenous ATG5 increased Ang II-induced phosphorylation and nuclear translocation of p65 and transcriptional activity of NF-kappa B, whereas the overexpressed ATG5, rather than ATG5 mutant K130R, hampered activation of NF-kappa B signaling, suggest an autophagy-dependent anti-inflammatory effect of ATG5. Further, pharmacological manipulation of autophagy yielded similar results both in vivo and in vitro. Additionally, JSH-23, a specific inhibitor of NF-kappa B nuclear translocation, rescued Ang II-driven IL-1 beta production in ATG5 siRNA-treated cells and decreased the proportion of cells in G2/M phase. In conclusion, ATG5-mediated autophagy in tubules targets NF-kappa B signaling to protect against renal inflammation.