Polyphyllin VII promotes hepatic stellate cell ferroptosis via the HIC1/CX3CL1/GPX4 axis

Ferroptosis has been shown to mediate the development of fibrosis. Polyphyllin VII (PP7), a bioactive component of <i>Paris polyphylla</i>, exhibits potent anti-inflammatory activity and can significantly alleviate liver fibrosis. In this study, treatment with PP7 significantly inhibited the proliferation and activation of hepatic stellate cells (HSCs), which could be suppressed by a ferroptosis inhibitor. In addition, it promoted HSC ferroptosis by suppressing glutathione (GSH) peroxidase 4 (GPX4) and enhanced the expression of CX3C chemokine ligand 1 (CX3CL1). Depletion of CX3CL1 attenuated the effects of PP7 on the activation and ferroptosis of HSCs and the expression of GPX4. Notably, CX3CL1 directly interacted with GPX4, triggering HSC ferroptosis. The transcription factor hypermethylated in cancer 1 (<i>Hic1</i>), which binds to the <i>Cx3cl1</i> promoter, increased the expression of CX3CL1. Its absence resulted in downregulation of CX3CL1, suppressing the GPX4-dependent ferroptosis of PP7-treated HSCs and promoting their activation. HIC1 was found to directly interact with PP7 at the GLY164 site. Co-culture experiments showed that PP7-induced HSC ferroptosis attenuated macrophage recruitment by regulating inflammation-related genes. HSC-specific inhibition of HIC1 counteracted PP7-induced collagen depletion and HSC ferroptosis <i>in vivo</i>. These findings suggest that PP7 induces HSC ferroptosis through the HIC1/CX3CL1/GPX4 axis.