Transcriptomics reveal a molecular signature in the progression of nonalcoholic steatohepatitis and identifies PAI­1 and MMP­9 as biomarkers in in vivo and in vitro studies.

Nonalcoholic steatohepatitis (NASH) is emerging as the primary driver of liver disease­induced fibrosis. The imperative need for noninvasive biomarkers to ascertain disease progression stage is evident. The present study elucidated the biological roles of hub genes that could potentially serve as diagnostic markers for NASH. Using an in vivo approach, C57BL/6J mice were subjected to a high­fat and fructose diet (HFFD) for 6, 10, 14, 18 or 22 weeks. Serological biochemical indices were assessed and liver specimens were obtained to identify potential markers linked to the NASH process, employing a comprehensive strategy that combined transcriptomic and histopathological analyses. The HFFD regimen induced hyperlipidemia, obesity and insulin resistance, progressively culminating in NASH with fibrosis over time. The transcriptomic analyses indicated temporal patterns of pivotal gene sets intricately connected to NASH progression, which encompassed processes such as glucose homeostasis, inflammatory responses, reactive oxygen species­mediated damage, lipid metabolism disruptions and the formation of fibrotic tissue. Among these genes, Serpine1 and Mmp9 demonstrated promising diagnostic potential for NASH, with their intrahepatic mRNA expression levels serving as robust indicators. Moreover, the levels of PAI­1 (encoded by the Serpine1 gene) and MMP­9 in the serum of mice demonstrated a parallel increase with the duration of HFFD intervention. In vitro experiments utilizing HepG2 cells further validated these findings, demonstrating a significant elevation in the protein expression levels of both PAI­1 and MMP­9 upon exposure to free fatty acids, in agreement with the results of the animal study. Consequently, PAI­1 and MMP­9 are promising noninvasive biomarkers for assessing the progression of NASH.