NCX1/Ca²⁺ signal pathway contributes to the autophagy regulation during TGF-β-induced hepatic stellate cell activation

Background and Aims:The main mechanism of liver fibrosis is the activation of hepatic stellate cells (HSCs).Studies found that HSCs activation is closely related to autophagy. NCX1 pays an important role in the regulation of intracellular Ca²⁺ homeostasis. This study aims to explore the potential mechanism of NCX1-mediated Ca²⁺ influx to regulate autophagy during the activation of HSCs. Methods: Western-blot and Immunohistochemistry was used to detect  the expression of autophagy genes , a-SMA and NCX1.The NCX1 function was examined using cell calcium imaging. Observation of the changes of autophagosomes and autophagic flow of HSCs by electron microscope and fluorescence microscope. Result: Clinical liver tissue samples found that NCX1 expression was positively correlated with α-SMA and autophagy gene LC3II. Mouse liver fibrosis models  found that, compared with the model group, the treatment group (intraperitoneal injection of NXC1 inhibitor KB-R7943) mouse liver tissue NCX1, α-SMA, LC3II,ATG7 was reduced. In cell experiments, we  confirmed that NCX1 is functionally expressed in HSCs activation. After inhibiting NCX1, LC3II, ATG7 and α-SMA decreased,P62 expression was restored, and autophagosome decreased.Further studies confirmed that NCX1-mediated intracellular calcium activation can activate the PI3K/AKT pathway, thereby promoting FOXO1 nuclear translocation to regulate autophagy genes expression in HSCs.Conclusion: NCX1-mediated calcium signal play an important role in autophagy of HSC activation, implying that targeting the novel NCX1/Ca²⁺/FOXO1 pathway might serve as therapeutic strategies for the Liver fibrosis.