Exploring the molecular mechanisms through which overexpression of TET3 alleviates liver fibrosis in mice via ferroptosis in hepatic stellate cells

Hepatic stellate cell (HSC) activation is crucial in the onset and progression of liver fibrosis, and inhibiting or eliminating activated HSCs is a key therapeutic strategy. Ferroptosis may help eliminate activated HSCs; however, its role and regulatory pathways in liver fibrosis remain unclear. As a DNA demethylase, TET3 regulates gene expression via DNA demethylation. We previously demonstrated that TET3 overexpression alleviates CCL₄-induced liver fibrosis in mice; however, the specific mechanisms, including whether TET3 affects ferroptosis in HSCs, remain unexplored. Thus, we aimed to explore the molecular mechanisms wherein TET3 overexpression improves liver fibrosis in mice via ferroptosis in HSCs. Our in vivo observations showed that overexpression of TET3 ameliorate liver fibrosis in mice, and is associated with increased levels of malondialdehyde (MDA) and Fe²⁺ in liver tissue, as well as decreased protein expression of SLC7A11, GPX4, and FTH1. Further in vitro studies on HSCs showed that TET3 overexpression inhibits the expression of SLC7A11, GPX4, and FTH1, and reduces intracellular GSH levels, leading to accumulation of MDA and iron ions. This induces ferroptosis in HSC-LX2 cells, while simultaneously decreasing ECM accumulation in HSCs. Furthermore, hMeDIP-SEQ and ChIP-qPCR analyses revealed that TET3 directly interacts with the promoter regions of GPX4 and FTH1 to regulate their transcriptional expression. We propose that overexpression of TET3 modulates the gene methylation status of ferroptosis-related proteins, thereby regulating HSC ferroptosis, reducing activated HSCs, and decreasing ECM deposition in the liver. This may represent one of the molecular mechanisms wherein TET3 overexpression ameliorates liver fibrosis in mice.