Exosomal miR‐122, miR‐128, miR‐200, miR‐298, and miR‐342 as novel diagnostic biomarkers in NAFL/NASH: Impact of LPS/TLR‐4/FoxO3 pathway

Abstract Nonalcoholic fatty liver disease (NAFLD) is a common liver disorder affecting a quarter of the global residents. Progression of NAFL into nonalcoholic steatohepatitis (NASH) may cause cirrhosis, liver cancer, and failure. Gut microbiota imbalance causes microbial components translocation into the circulation, triggering liver inflammation and NASH‐related fibrosis. MicroRNAs (miRNAs) regulate gene expression via repressing target genes. Exosomal miRNAs are diagnostic and prognostic biomarkers for NAFL and NASH liver damage. Our work investigated the role of the gut microbiota in NAFLD pathogenesis via the lipopolysaccharide/toll‐like receptor 4/Forkhead box protein O3 (LPS/TLR‐4/FoxO3) pathway and certain miRNAs as noninvasive biomarkers for NAFL or its development to NASH. miRNA expression levels were measured using quantitative reverse transcription polymerase chain reaction (qRT‐PCR) in 50 NAFL patients, 50 NASH patients, and 50 normal controls. Plasma LPS, TLR‐4, adiponectin, peroxisome proliferator‐activated receptor γ (PPAR‐γ), and FoxO3 concentrations were measured using enzyme‐linked immunosorbent assay (ELISA). In NAFL and NASH patients, miR‐122, miR‐128, FoxO3, TLR‐4, LPS, and PPAR‐γ were upregulated while miR‐200, miR‐298, miR‐342, and adiponectin were downregulated compared with the normal control. The examined miRNAs might distinguish NAFL and NASH patients from the normal control using receiver operating characteristic analysis. Our study is the first to examine these miRNAs in NAFLD. Our findings imply that these are potentially promising biomarkers for noninvasive early NAFL diagnosis and NASH progression. Understanding the LPS/TLR‐4/FoxO3 pathway involvement in NAFL/NASH pathogenesis may aid disease management.