Department of Thoracic Surgery, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, 200080, PR China; Department of Cardiac Surgery, The First Affiliated Hospital of Soochow University, Soochow, 215006, PR China.
Department of Thoracic Surgery, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, 200080, PR China.
Arch Biochem Biophys. 2019 Sep 15;672:108061. doi: 10.1016/j.abb.2019.07.026. Epub 2019 Jul 26.
Autophagy exerts a dual role in promoting cell death or survival. Recent studies have shown that it may play an important role in lipopolysaccharide (LPS)-induced acute lung injury (ALI). It was also suggested that angiotensin converting enzyme 2 (ACE2) may participate in the regulation of autophagy. The present study aims to investigate the role of autophagy in ALI and the involvement of ACE2. The regulation of the APMK/mTOR pathway was explored to clarify the underlying mechanism. The results showed that autophagy played an important role in ALI induced by LPS, as the autophagy inhibitor 3-methyladenine (3-MA) mitigated the severity of ALI. ACE2 activator resorcinolnaphthalein and inhibitor MLN-4760 significantly affected the histological appearance and wet/dry (W/D) ratio of the lung and altered the ACE2 activity of the lung, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels in bronchoalveolar lavage fluid (BALF) and myeloperoxidase (MPO) levels in lung tissue. Furthermore, LPS, resorcinolnaphthalein and MLN-4760 significantly affected the expression of autophagy proteins Beclin-1, LC3-I and LC3-II. To explore the mechanism of ACE2 on lung autophagy, we measured the phosphorylation of AMPK/mTOR after mice were treated with LPS and resorcinolnaphthalein or MLN-4760. The results revealed that resorcinolnaphthalein and MLN-4760 both significantly altered the phosphorylation of AMPK/mTOR. Finally, we found that AMPK inhibitor (8-bAMP) and mTOR activator (propranolol) both abolished the effects of ACE2 activator (resorcinolnaphthalein) on the expression of lung autophagy proteins Beclin-1, LC3-I and LC3-II. In conclusion, these findings suggest that ACE2 could alleviate the severity of ALI, inflammation and autophagy in lung tissue through the AMPK/mTOR pathway.
自噬在促进细胞死亡或存活方面发挥着双重作用。最近的研究表明，它可能在脂多糖（LPS）诱导的急性肺损伤（ALI）中发挥重要作用。也有人提出血管紧张素转换酶 2（ACE2）可能参与自噬的调节。本研究旨在探讨自噬在 ALI 中的作用以及 ACE2 的参与情况。探讨了 APMK/mTOR 通路的调节，以阐明其潜在机制。结果表明，自噬在 LPS 诱导的 ALI 中发挥重要作用，自噬抑制剂 3-甲基腺嘌呤（3-MA）减轻了 ALI 的严重程度。ACE2 激活剂间苯二酚萘酚和抑制剂 MLN-4760 显著影响肺的组织学外观和干湿（W/D）比，并改变肺 ACE2 活性、肿瘤坏死因子-α（TNF-α）和白细胞介素-1β（IL-1β）在支气管肺泡灌洗液（BALF）中的水平和肺组织中的髓过氧化物酶（MPO）水平。此外，LPS、间苯二酚萘酚和 MLN-4760 显著影响自噬蛋白 Beclin-1、LC3-I 和 LC3-II 的表达。为了探讨 ACE2 对肺自噬的作用机制，我们测量了 LPS 处理后小鼠的 AMPK/mTOR 磷酸化。结果表明，间苯二酚萘酚和 MLN-4760 均显著改变了 AMPK/mTOR 的磷酸化。最后，我们发现 AMPK 抑制剂（8-bAMP）和 mTOR 激活剂（心得安）均消除了 ACE2 激活剂（间苯二酚萘酚）对肺自噬蛋白 Beclin-1、LC3-I 和 LC3-II 表达的影响。总之，这些发现表明，ACE2 可以通过 AMPK/mTOR 通路减轻 ALI、肺组织炎症和自噬的严重程度。
