Inhibition of IRE1α/XBP1 axis alleviates LPS-induced acute lung injury by suppressing TXNIP/NLRP3 inflammasome activation and ERK/p65 signaling pathway

Respir Res. 2024 Nov 27;25(1):417. doi: 10.1186/s12931-024-03044-1.

Abstract

Background: Acute lung injury or acute respiratory distress syndrome (ALI/ARDS) is a devastating clinical syndrome with high incidence and mortality rates. IRE1α-XBP1 pathway is one of the three major signaling axes of endoplasmic reticulum stress that is involved in inflammation, metabolism, and immunity. The role and potential mechanisms of IRE1α-XBP1 axis in ALI/ARDS has not well understood.

Methods: The ALI murine model was established by intratracheal administration of lipopolysaccharide (LPS). Hematoxylin and eosin (H&E) staining and analysis of bronchoalveolar lavage fluid (BALF) were used to evaluate degree of lung injury. Inflammatory responses were assessed by ELISA and RT-PCR. Apoptosis was evaluated using TUNEL staining and western blot. Moreover, western blot, immunohistochemistry, and immunofluorescence were applied to test expression of IRE1α, XBP1, NLRP3, TXNIP, IL-1β, ERK1/2 and NF-κB p65.

Results: The expression of IRE1α significantly increased after 24 h of LPS treatment. Inhibition of the IRE1α-XBP1 axis with 4µ8C notably improved LPS-induced lung injury and inflammatory infiltration, reduced the levels of IL-6, IL-1β, and TNF-α, and decreased cell apoptosis as well as the activation of the NLRP3 inflammasome. Besides, in LPS-stimulated Beas-2B cells, both 4µ8C and knockdown of XBP1 diminished the mRNA levels of IL-6 and IL-1B, inhibited cell apoptosis and reduced the protein levels of TXNIP, NLRP3 and secreted IL-1β. Mechanically, the phosphorylation and nuclear translocation of ERK1/2 and p65 were significantly suppressed by 4µ8C and XBP1 knockdown.

Conclusions: In summary, our findings suggest that IRE1α-XBP1 axis is crucial in the pathogenesis of ALI/ARDS, whose suppression could mitigate the pulmonary inflammatory response and cell apoptosis in ALI through the TXNIP/NLRP3 inflammasome and ERK/p65 signaling pathway. Our study may provide new evidence that IRE1α-XBP1 may be a promising therapeutic target for ALI/ARDS.

Keywords: Acute lung injury; ERK/p65; IRE1α-XBP1 axis; Inflammation; NRLP3.

MeSH terms

  • Acute Lung Injury* / chemically induced
  • Acute Lung Injury* / metabolism
  • Acute Lung Injury* / pathology
  • Acute Lung Injury* / prevention & control
  • Animals
  • Carrier Proteins* / genetics
  • Carrier Proteins* / metabolism
  • Endoribonucleases* / metabolism
  • Inflammasomes* / metabolism
  • Lipopolysaccharides* / toxicity
  • MAP Kinase Signaling System / drug effects
  • MAP Kinase Signaling System / physiology
  • Male
  • Mice
  • Mice, Inbred C57BL*
  • NLR Family, Pyrin Domain-Containing 3 Protein* / antagonists & inhibitors
  • NLR Family, Pyrin Domain-Containing 3 Protein* / metabolism
  • Protein Serine-Threonine Kinases* / genetics
  • Protein Serine-Threonine Kinases* / metabolism
  • Signal Transduction / drug effects
  • Signal Transduction / physiology
  • Thioredoxins
  • Transcription Factor RelA* / metabolism
  • X-Box Binding Protein 1* / genetics
  • X-Box Binding Protein 1* / metabolism

Substances

  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Protein Serine-Threonine Kinases
  • Lipopolysaccharides
  • Endoribonucleases
  • X-Box Binding Protein 1
  • Inflammasomes
  • Ern1 protein, mouse
  • Carrier Proteins
  • Xbp1 protein, mouse
  • Nlrp3 protein, mouse
  • Transcription Factor RelA
  • Txnip protein, mouse
  • Rela protein, mouse
  • Thioredoxins