Compound C1 reduced inflammation and activated autophagy in alveolar macrophages in mice

The purpose of this study was to investigate the therapeutic effect of Compound C1 (Comp-C1) on lipopolysaccharide (LPS) -mediated sepsis acute lung injury (SALI) in vitro alveolar macrophage model and its regulatory mechanism. In vitro cultured mouse alveolar macrophages (MH-S) were treated with LPS. The expression and localization of transcription factor EB (TFEB) after LPS stimulation were detected. Then the cells were treated with LPS (1 μg/mL) and Comp-C1 (1 μM) for 24 h. RT-qPCR and Western Blot were used to detect the mRNA expression of inflammatory factors. Western blot was used to detect the expression of TFEB, lysosome-associated membrane protein 1 (LAMP1), P62 and microtubule-associated protein 1 light chain 3B (LC3B). TFEB-EGFP-Hela and mCherry-EGFP-LC3-Hela cells were used to detect the changes of TFEB nuclear expression and intracellular autophagic flux after Comp-C1 administration by immunofluorescence. The results showed that the expression of inflammatory factors was the highest after 1 μg / mL LPS stimulation for 24 hours. At the same time, the expression of TFEB gene and protein decreased after LPS stimulation, and the content of TFEB in cytoplasm and nucleus decreased by separating cytoplasmic and nuclear proteins. The content of LAMP1 decreased, and the expression of autophagy-related proteins reflected the inhibition of autophagy. After treatment with Comp-C1, the inflammatory factors were significantly decreased, the expression of TFEB and LAMP1 was significantly increased, and the expression of autophagy genes in the cells was restored. The up-regulation of TFEB nuclear expression after Comp-C1 administration was determined by TFEB-EGFP-Hela cells, and the recovery of autophagy flux and alveolar macrophage function after Comp-C1 administration was determined by mCherry-EGFP-LC3-Hela cells. Therefore, Comp-C1 can alleviate LPS-induced MH-S autophagy dysfunction and reduce inflammatory response by up-regulating TFEB in mouse alveolar macrophages, suggesting that Comp-C1 can be used as a potential drug for the treatment of SALI.