HSPB8 attenuates lipopolysaccharide­mediated acute lung injury in A549 cells by activating mitophagy.

ABSTRACT

Sepsis is a life­threatening multiple organ failure disease caused by an uncontrolled inflammatory response and can progress to acute lung injury (ALI). Heat­shock protein B8 (HSPB8) serves a cytoprotective role in multiple types of diseases; however, to the best of our knowledge, the regulatory role of HSPB8 in sepsis­induced ALI remains unclear. A549 human alveolar type II epithelial cells were treated with lipopolysaccharide (LPS) for 24 h to simulate a sepsis­induced ALI model. Cell transfection was performed to overexpress HSPB8, and cells were treated with mitochondrial division inhibitor­1 (Mdivi­1) for 2 h before LPS induction to assess the underlying mechanism. Protein expression was evaluated using western blotting and an immunofluorescence assay. Cytokines were examined using ELISA assay kits and antioxidant enzymes were examined using their detection kits. Cell apoptosis was detected using flow cytometry. The mitochondrial membrane potential was detected by JC­1 staining. HSPB8 was upregulated in A549 cells treated with LPS and HSPB8 overexpression attenuated LPS­induced inflammatory cytokine levels, oxidative stress and apoptosis in A549 cells. LPS inhibited mitophagy and reduced the mitochondrial membrane potential in A549 cells, which was partly inhibited by HSPB8 overexpression. Furthermore, Mdivi­1 decreased the inhibitory effect of HSPB8 on the inflammatory response, oxidative stress and apoptosis in LPS­treated A549 cells. In conclusion, HSPB8 overexpression attenuated the LPS­mediated inflammatory response, oxidative stress and apoptosis in A549 cells by promoting mitophagy, indicating HSPB8 as a potential therapeutic target in sepsis­induced ALI.