GOLPH3 knockdown alleviates the inflammation and apoptosis in lipopolysaccharide-induced acute lung injury by inhibiting Golgi stress mediated autophagy

Abstract

Pneumonia, an acute inflammatory lesion of the lung, is the leading cause of death in children aged < 5 years. We aimed to study the function and mechanism of Golgi phosphoprotein 3 (GOLPH3) in infantile pneumonia. Lipopolysaccharide (LPS)-induced acute lung injury (ALI) mice and injury of MLE-12 cells were used as the pneumonia model in vitro. After GOLPH3 was knocked down, the histopathological changes of lung tissues were assessed by hematoxylin-eosin (H&E) staining. The Wet/Dry ratio of lung tissues was calculated. The enzyme-linked immunosorbent assay (ELISA) method was used to detecte the contents of inflammatory factors in bronchoalveolar lavage fluid (BALF). The damaged DNA in apoptotic cells in lung tissues was tested by Terminal deoxynucleotidyl transferase-mediated dUTP Nick end labeling (TUNEL) staining. Immunofluorescence staining analyzed LC3II and Golgi matrix protein 130 (GM130) expression in lung tissues and MLE-12 cells. The apoptosis of MLE-12 cells was measured by flow cytometry analysis. Additionally, the expression of proteins related to apoptosis, autophagy and Golgi stress was examined with immunoblotting. Results indicated that GOLPH3 knockdown alleviated lung tissue pathological changes in LPS-triggered ALI mice. LPS-induced inflammation and apoptosis in lung tissues and MLE-12 cells were remarkably alleviated by GOLPH3 deficiency. Besides, GOLPH3 depletion suppressed autophagy and Golgi stress in lung tissues and MLE-12 cells challenged with LPS. Moreover, Rapamycin (Rap), an autophagy inhibitor, counteracted inflammation and apoptosis inhibited by GOLPH3 silencing in LPS-induced MLE-12 cells. Furthermore, brefeldin A (BFA) pretreatment apparently abrogated the inhibitory effect of GOLPH3 knockdown on autophagy in MLE-12 cells exposed to LPS. To be concluded, GOLPH3 knockdown exerted lung protective effect against LPS-triggered inflammation and apoptosis by inhibiting Golgi stress mediated autophagy.