SZ168 treats LPS-induced acute lung injury by inhibiting the activation of NF-κB and MAPKs pathways

This study aimed to elucidate the effect and underlying molecular mechanisms of SZ168 (Podoplanin (PDPN) monoclonal antibody) on lipopolysaccharide (LPS)-induced acute lung injury (ALI) mice and LPS-induced MH-S cells.The survival rate was calculated by recording the death of mice in each group. Enzyme linked immunosorbent assay (ELISA) was used to detect the levels of interleukin (IL)- 6 and tumor necrosis factor-alpha (TNF-α) in blood and bronchoalveolar lavage fluid (BALF) of mice. Hematoxylin-eosin (H&E) staining were performed to evaluate the pathological changes in pulmonary tissues. Additionally, the phagocytosis of cells was tested by flow cytometry, and the expression levels of caveolin-1 (CAV-1) and Occludin proteins in lung tissue and the expression of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathway-related proteins in MH-S cells were determined by western blot.SZ168 significantly improved the survival rate of ALI mice. Briefly speaking, SZ168 protected pulmonary vascular permeability, reduced the level of pro-inflammatory cytokines, improved the pathological changes of lung tissue, reduced the infiltration of inflammatory cells, increased CAV-1 and Occludin protein expression, and then effectively relieved lung injury. In addition, SZ168 could significantly reduce the phagocytic ability of LPS-induced MH-S cells and inhibit the expression of hospho-extracellular regulated protein kinases (p-ERK), Phospho-Jun N-terminal kinase (p-JNK), Phospho-NF-κB p65 (p-p65) and Phospho-IkappaB-alpha (p-IκBα).SZ168 can treat ALI by inhibiting the activation of NF-κB and MAPK signaling pathways and restoring tight junction protein expression.