Lc3 Over-Expression Improves Survival and Attenuates Lung Injury Through Increasing Autophagosomal Clearance in Septic Mice
Lc3 Over-Expression Improves Survival and Attenuates Lung Injury Through Increasing Autophagosomal Clearance in Septic Mice
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DOI：
10.1097/sla.0b013e318269d0e2
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发表时间：
2013-02-01
影响因子：
9
通讯作者：
Hsieh, Ya-Ching
中科院分区：
文献类型：
--
作者：
Lo, Steven;Yuan, Shyng-Shiou F.;Hsieh, Ya-Ching
目的：阐明自噬在脓毒症肺损伤中的作用。背景：自噬在脓毒症肺细胞中作为保护性或适应不良反应的作用尚未确定。缺乏特异性的自噬过程已经推动了新方法的发展，assesssautophagosomes从形成到融合lysosome.Methods：脓毒症引起盲肠结扎穿孔（CLP）。使用自噬途径的药理学抑制剂操纵自噬过程。绿色荧光蛋白（GFP）-微管相关蛋白1轻链3（LC 3）转基因小鼠进一步用于确定自噬的作用。结果：CLP后24 h，自噬体蛋白LC 3-II的形成在肺中进行性积累，LC 3基因表达在24 h恢复到基线水平。然而，自噬体-溶酶体融合在CLP后8至24小时逐渐减少，表明脓毒症肺中自噬体的清除受损，而不是自噬的上调。相反，过表达Lc 3基因的转基因小鼠表现出自噬体清除率增加，CLP后存活率提高。这种保护作用也见于细胞死亡减少、炎症反应、中性粒细胞蓄积、白蛋白渗漏和水肿形成。然而，阻断自噬体-溶酶体融合与巴弗洛霉素A1废除了转基因小鼠的保护作用。这表明，Lc 3转基因减弱肺损伤/炎症脓毒症，可能通过增加清除自噬体。结论：自噬在脓毒症肺代表一种保护性反应。自噬在脓毒症晚期可能发挥适应不良的作用，导致急性肺损伤。
Objective: To clarify the role of autophagy in sepsis-induced lung injury.Background: The role of autophagy as a protective or maladaptive response in lung cells during sepsis has not yet been determined. The lack of specificity of the autophagic process has driven the development of new approaches that assessautophagosomes from formation to fusion with lysosomes.Methods: Sepsis was induced by cecal ligation and puncture (CLP). The autophagic process was manipulated using the pharmacological inhibitors of the autophagy pathway. Green fluorescent protein (GFP)-microtubule-associated protein 1 light chain 3 (LC3) transgenic mice were further used to determine the role of autophagy.Results: The formation of autophagosomal protein LC3-II progressively accumulated in the lungs over 24 hours after CLP, with the Lc3 gene expression returning to baseline levels at 24 hours. Autophagosome-lysosome fusion, however, gradually decreased from 8 to 24 hours after CLP, suggesting impaired clearance of autophagosomes rather than upregulation of autophagy in the septic lung. In contrast, transgenic mice overexpressing the Lc3 gene exhibited increased clearance of autophagosomes and improved survival after CLP. This protective effect was also seen in decreased cell death, inflammatory responses, neutrophil accumulation, albumin leakage, and edema formation. However, blockade of autophagosome-lysosome fusion with bafilomycin A1 abolished the protective effects in transgenic mice. This indicates that Lc3 transgene attenuates lung injury/inflammation in sepsis, possibly through increasing the clearance of autophagosomes.Conclusions: Autophagy in the septic lung represents a protective response. However, autophagy, by virtue of excessive autophagosome accumulation, may play a maladaptive role in the late stage of sepsis, leading to acute lung injury.