Sestrin 2 protects against LPS-induced acute lung injury by inducing mitophagy in alveolar macrophages

Life Sci. 2021 Feb 15:267:118941. doi: 10.1016/j.lfs.2020.118941. Epub 2020 Dec 24.

Abstract

Aims: Acute lung injury (ALI) / acute respiratory distress syndrome (ARDS) is a critical clinical syndrome with complex pathology and pathogenesis. Since there is no specific treatment for ALI, it is important to study the mechanism of how ALI develop. Sestrin2 (Sesn2) plays a critical role in the regulation of cellular stress response and oxidant defense. However, the potential function of Sesn2 in ALI/ARDS and the associated mechanism remains unclear.

Main methods: Lipopolysaccharide (LPS) induced ALI model was performed in the wild-type and Sesn2 knockout (Sesn2-/-) mice. The nod-like receptor protein 3 (NLRP3) inflammasome, cell pyroptosis and mitophagy were detected by western blots, immunofluorescent staining, flow cytometry. Lung injury were measured by histopathology and electron microscopy.

Key findings: Knockout of Sesn2 enhanced LPS-induced ALI. As detailed in Sesn2-/- mice, NLRP3 inflammasome and cell pyroptosis were increased in lungs; IL-1β and IL-18 in serum and bronchoalveolar lavage fluid (BALF) were further promoted; In the isolated alveolar macrophages from Sesn2-/- mice, mitophagy induced by LPS was markedly inhibited, while reactive oxygen species (ROS), mitochondrial damage and cell pyroptosis were enhanced. Knocking down or overexpressing Sensn2 in J774.A1 cells demonstrated Sesn2 promoted Sequestosome1 (SQSTM1) expression and mitophagy by PTEN-induced putative kinase 1 (Pink1)/Parkin pathway.

Significance: Sesn2 protected ALI by promoting mitophagy that exerts protection of AMs pyroptosis and negative regulation of NLRP3 inflammasomes. These data indicated Sesn2 might be a potential target for ALI treatment.

Keywords: Acute lung injury; Alveolar macrophage; Inflammasome; Mitophagy; Sestrin2.

MeSH terms

  • Acute Lung Injury / chemically induced
  • Acute Lung Injury / drug therapy
  • Acute Lung Injury / metabolism
  • Acute Lung Injury / prevention & control*
  • Animals
  • Bronchoalveolar Lavage Fluid
  • Disease Models, Animal
  • Inflammasomes / drug effects
  • Lipopolysaccharides / pharmacology
  • Macrophages, Alveolar / drug effects*
  • Macrophages, Alveolar / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mitophagy / drug effects*
  • NLR Family, Pyrin Domain-Containing 3 Protein / metabolism
  • Peroxidases / metabolism*
  • Pyroptosis / drug effects
  • Reactive Oxygen Species / metabolism

Substances

  • Inflammasomes
  • Lipopolysaccharides
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Nlrp3 protein, mouse
  • Reactive Oxygen Species
  • Peroxidases
  • Sesn2 protein, mouse