MitoQ Activates the AMPK-SIRT1 Pathway to Inhibit Pyroptosis in Lung Epithelial Cells and Alleviate Sepsis-Induced Acute Lung Injury

Objective: The mitochondrial coenzyme Q (MitoQ) has protective effects against oxidative stress and inflammatory responses. This study investigated the potential effect of MitoQ on alleviating sepsis-induced acute lung injury (ALI) by activating the adenosine monophosphate-activated protein kinase (AMPK)-sirtuin1 (SIRT1) pathway.Methods: The in vivo sepsis-induced ALI rat model and the in vitro A549 ALI cell model were used in this study. However, the untreated rats or cells were used as the control group and the MitoQ-treated models were used as the experimental group. The hematoxylin and eosin (H&E) staining was used to stain lung tissues. The effects of MitoQ were observed by calculating lung weight and lung permeability index (LPI). Furthermore, the levels of occluding, claudin-1, zonula occludens-1 (ZO-1), tumour necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1 beta), monocyte chemoattractant protein-1 (MCP-1), caspase-3, and nuclear factor-kappaB (NF-kappa B) were assessed using quantitative real-time polymerase chain reaction (qRT-PCR), for evaluating the junction integrity, apoptosis, and inflammation. Moreover, to examine the effect of MitoQ on the AMPK-SIRT pathway, the levels of p-AMPK/AMPK, and SIRT1 were evaluated using Western blot analysis. Additionally, the levels of gasdermin D (GSDMD), cleaved caspase 1, cleaved caspase 11, and lactate dehydrogenase (LDH) were used to investigate the effect of MitoQ on cell pyroptosis and cell damage. Additionally, the role of AMPK and SIRT1 pathways on pyroptosis and cellular damage was determined.Results: In the lung tissues of the ALI model group, the H&E-stained area (p < 0.01), the lung wet/dry weight ratio (p < 0.01), and the LPI were significantly increased (p < 0.01). Moreover, these values were counteracted with MitoQ treatment (p < 0.05). The ALI rats treated with MitoQ survived longer than those without treatment (p < 0.01). Furthermore, in the ALI model group (both in tissues and cells), a significant decrease was observed in the levels of occludin, claudin-1, ZO-1, caspase-3, and NF-kappa B (p < 0.01), while the levels of TNF-alpha, IL-1 beta, MCP-1, cleaved GSDMD, cleaved caspase-1, cleaved caspase-11, and LDH were significantly increased (p < 0.01). Interestingly, treatment with MitoQ reversed all of these factors (p < 0.05). In the ALI model group, the levels of p-AMPK/AMPK and SIRT1 proteins were significantly decreased (p < 0.01), and their levels were reversed following MitoQ treatment (p < 0.05). Furthermore, the compound C (CC) decreased the levels of p-AMPK/AMPK and SIRT1 (p < 0.01), while the SIRT1 antagonist Ex-527 decreased only the level of SIRT1 (p < 0.01). However, both the CC and Ex-527 reversed the levels of cleaved GSDMD (p < 0.01), cleaved caspase-1 (p < 0.05), cleaved caspase-11 (p < 0.01), and LDH (p < 0.01), which were inhibited by MitoQ in ALI cells.Conclusion: Our findings suggest that MitoQ exerts protective effects on sepsis-induced ALI by activating the AMPK-SIRT1 pathway and inhibiting pyroptosis. These results offer a potential therapeutic application of MitoQ in treating sepsis-induced lung injury and provide insights into the underlying mechanisms involved.