ZBP1 aggravates acute lung injury in mice by promoting the macrophage inflammatory phenotype

Background: Acute lung injury (ALI) is an acute lung inflammatory disease that is difficult to cure and has a poor prognosis. Macrophages play a key role in the pathogenesis of ALI, and their different phenotypes and functions affect the progression of the disease. This study aimed to explore how ZBP1 affects the progression of ALI via the regulation of macrophage inflammatory phenotype.

Methods: A RAW264.7 cell injury model and an ALI mouse model were established via LPS induction for experimental investigation. The degree of lung injury was determined by HE staining, the protein concentration in the bronchoalveolar lavage fluid (BALF), the wet/dry weight ratio of the lung tissue, and lung myeloperoxidase (MPO) activity. The levels of related proteins, genes and inflammatory factors were detected via Western blotting, RT-qPCR and ELISA. Bioinformatics prediction and dual-luciferase reporter gene assays were used to demonstrate the interaction between miR-1298-5p and ZBP1.

Results: ZBP1 was highly expressed in ALI and its expression was associated with the degree of M1 macrophage polarization. ZBP1 knockdown significantly attenuated LPS-induced pathological damage to lung tissue and reduced the lung wet/dry weight ratio, protein content in BALF, MPO activity and levels of the proinflammatory cytokines IL-1β, IL-6, and TNF-α in lung tissue. Further studies revealed that ZBP1 knockdown inhibited the activation of the NF-κB signaling pathway, thereby reducing ROS levels while increasing the mitochondrial membrane potential, ATP content and expression of the mitochondrial protein TOM20, ultimately ameliorating mitochondrial dysfunction. Mechanistically, miR-1298-5p is expressed at low levels in ALI and negatively regulates ZBP1 expression. In addition, the NF-κB Activator PMA reversed the inhibitory effect of ZBP1 knockdown on M1 macrophage polarization.

Conclusion: miR-1298-5p downregulates ZBP1 expression and inhibits NF-κB signaling pathway-mediated mitochondrial dysfunction, thereby inhibiting the M1 polarization of macrophages and the progression of ALI.

Acute lung injury; Macrophage polarization; Mitochondrial dysfunction; NF-κB signaling pathway; ZBP1; miR-1298-5p.