GLP-1 Analogue Liraglutide Enhances SP-A Expression in LPS-Induced Acute Lung Injury through the TTF-1 Signaling Pathway

Mediators Inflamm. 2018 May 22:2018:3601454. doi: 10.1155/2018/3601454. eCollection 2018.

Abstract

The reduction of pulmonary surfactant (PS) is essential for decreased pulmonary compliance and edema in acute lung injury (ALI). Thyroid transcription factor-1 (TTF-1) plays a major role in the regulation of surfactant protein-A (SP-A), the most abundant protein component of PS. Simultaneously, the glucagon-like peptide-1 (GLP-1) analogue can enhance SP-A expression in the lung. However, the underlying mechanism is still unknown. The purpose of this study was to explore whether liraglutide, a GLP-1 analogue, upregulates SP-A expression through the TTF-1 signaling pathway in ALI. In vivo, a murine model of ALI was induced by lipopolysaccharide (LPS). Pulmonary inflammation, edema, insulin level, ultrastructural changes in type II alveolar epithelial (ATII) cells, and SP-A and TTF-1 expression were analyzed. In vitro, rat ATII cells were obtained. SP-A and TTF-1 expression in cells was measured. ShRNA-TTF-1 transfection was performed to knock down TTF-1 expression. Our data showed that LPS-induced lung injury and increase in insulin level, and LPS-induced reduction of SP-A and TTF-1 expression in both the lung and cells, were significantly compromised by liraglutide. Furthermore, we also found that these effects of liraglutide were markedly blunted by shRNA-TTF-1. Taken together, our findings suggest that liraglutide enhances SP-A expression in ATII cells and attenuates pulmonary inflammation in LPS-induced ALI, most likely through the TTF-1 signaling pathway.

MeSH terms

  • Acute Lung Injury / chemically induced*
  • Acute Lung Injury / drug therapy*
  • Acute Lung Injury / metabolism
  • Animals
  • Glucagon-Like Peptide 1 / analogs & derivatives*
  • Lipopolysaccharides / toxicity*
  • Liraglutide / therapeutic use*
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Pulmonary Surfactant-Associated Protein A / metabolism*
  • Rats
  • Signal Transduction / drug effects
  • Thyroid Nuclear Factor 1 / metabolism*

Substances

  • Lipopolysaccharides
  • Pulmonary Surfactant-Associated Protein A
  • Thyroid Nuclear Factor 1
  • Liraglutide
  • Glucagon-Like Peptide 1