RNA Sequencing of LX-2 Cells Treated with TGF-β1 Identifies Genes Associated with Early Hepatic Stellate Cell Activation

Hepatic stellate cells (HSCs) are liver-resident myofibroblast precursors. In chronic liver disease, HSC-derived myofibroblasts are responsible for the production of collagen and, as such, are generally associated with diseases characterised by hepatic fibrosis. HSCs undergo a process of "activation" in response to tissue damage or pathogen invasion, thereby assuming roles in extracellular matrix synthesis, wound healing, and pathogen defence. The process of HSC activation and collagen production is most commonly driven by the cytokine transforming growth factor-β1 (TGF-β1). To investigate the transcriptional impact of TGF-β1 signalling on liver myofibroblasts, RNA sequencing was used to quantitate the biological changes observed in LX-2 cells, an activated human HSC line, following TGF-b1 treatment. In total, 5,258 genes were found to be significantly differentially expressed with a false discovery rate cut-off of < 0.1. The topmost deregulated of these genes included those with known roles in influencing HSC activity, as well as those involved in fibrotic responses in other cell lines and tissues. Interestingly, genes with no currently characterised role in either HSC activation or fibrotic processes were also identified, including CIITA and SERPINB2. Further in silico analysis revealed the prominent signalling pathways downstream of TGF-β1 in LX-2 cells, which will be useful for improving the understanding of how this cytokine influences broader signalling pathways in the activation of HSCs. This work may be of use in the identification of new markers of liver fibrosis and could provide insight into prospective genes or pathways that might be targeted for the amelioration of fibrotic liver disease in the future.