Cigarette smoke extract combined with LPS down-regulates the expression of MRP2 in chronic pulmonary inflammation may be related to FXR

Cigarette smoke extract combined with LPS reduces ABCA3 expression in chronic pulmonary inflammation may be related to PPARγ/ P38 MAPK signaling pathway

ABCA3 (ATP-binding cassette class A3) is a transmembrane transporter that plays a positive role in chronic pulmonary inflammation by regulating lipid metabolism. However, it is not completely clear whether ABCA3 and its signaling factors are involved in chronic pulmonary inflammation induced by the combination of CSE (cigarette smoke extract) and LPS (lipopolysaccharide). In this study, we used the method of combining CSE and LPS which was widely used to study lung inflammation-related diseases and has been proven effective in our group's studies to create in vivo and in vitro pulmonary inflammation models. The result showed that, after CSE in combination with LPS treatment, ABCA3 expression was downregulated in rat lung in vivo and in a human alveolar cell line in vitro. ABCA3 expression was upregulated, and related inflammatory factors were downregulated in the state of overexpression of PPARγ or inhibition of the p38 MAPK pathway, while PPARγ deletion or MAPK14 overexpression showed the opposite results. The level of PPARγ remained unchanged, and the expression of ABCA3 was upregulated in the state of the p38 MAPK pathway was inhibited under overexpression of PPARγ. These results indicate that CSE combined with LPS can result in downregulation of ABCA3 under conditions of inflammation, and that the p38 MAPK signaling pathway mediated by PPARγ can regulate the expression changes of ABCA3, thus providing new targets for treating chronic pulmonary inflammation.

Impacts of Cigarette Smoking Status on Metabolomic and Gut Microbiota Profile in Male Patients With Coronary Artery Disease: A Multi-Omics Study

Background: Cigarette smoking has been considered a modifiable risk factor for coronary artery disease (CAD). Changes in gut microbiota and microbe-derived metabolites have been shown to influence atherosclerotic pathogenesis. However, the effect of cigarette smoking on the gut microbiome and serum metabolites in CAD remains unclear. Method: We profiled the gut microbiota and serum metabolites of 113 male participants with diagnosed CAD including 46 current smokers, 34 former smokers, and 33 never smokers by 16S ribosomal RNA (rRNA) gene sequencing and untargeted metabolomics study. A follow-up study was conducted. PICRUSt2 was used for metagenomic functional prediction of important bacterial taxa. Results: In the analysis of the microbial composition, the current smokers were characterized with depleted Bifidobacterium catenulatum, Akkermansia muciniphila, and enriched Enterococcus faecium, Haemophilus parainfluenzae compared with the former and never smokers. In the untargeted serum metabolomic study, we observed and annotated 304 discriminant metabolites, uniquely including ceramides, acyl carnitines, and glycerophospholipids. Pathway analysis revealed a significantly changed sphingolipids metabolism related to cigarette smoking. However, the change of the majority of the discriminant metabolites is possibly reversible after smoking cessation. While performing PICRUSt2 metagenomic prediction, several key enzymes (wbpA, nadM) were identified to possibly explain the cross talk between gut microbiota and metabolomic changes associated with smoking. Moreover, the multi-omics analysis revealed that specific changes in bacterial taxa were associated with disease severity or outcomes by mediating metabolites such as glycerophospholipids. Conclusions: Our results indicated that both the gut microbiota composition and metabolomic profile of current smokers are different from that of never smokers. The present study may provide new insights into understanding the heterogenic influences of cigarette smoking on atherosclerotic pathogenesis by modulating gut microbiota as well as circulating metabolites.