Mechanisms of apigenin in mitigating APAP-induced hepatocyte pyroptosis and liver injury via TRPV4 activation and ESCRT-mediated membrane repair

Abstract Acetaminophen (APAP)-induced liver injury is a major cause of liver failure and involves multiple intracellular events, including mitochondrial damage, oxidative stress and inflammation. As an intrinsic inflammatory process, pyroptosis plays a crucial role in cellular lysis and pro-inflammatory cytokine release. Transient receptor potential vanilloid 4 (TRPV4), described as a calcium-permeable cation channel, is associated with proinflammatory factors and pyroptosis. An increase of cytosolic Ca2+ plays a key role in the activation of the endosomal sorting complexes required for transport (ESCRT)-mediated membrane repair mechanism. Apigenin is a plant-derived flavone, which has potential preventive effects on the development of liver injury and has previously been reported as a TRP activator, activating TRPV4 channel. Thus, we speculated that novel mechanisms of alleviating APAP-induced hepatocyte pyroptosis and liver injury might be discovered through TRPV4 channel and ESCRT-mediated membrane repair. Our results showed that apigenin could indeed mitigate hepatocyte pyroptosis and liver injury induced by APAP. Further mechanism studies showed that apigenin could activate TRPV4 channel to induce calcium influx, while the increase of intracellular Ca2+ played a key role in the activation of ESCRT-mediated membrane repair mechanisms. In order to elucidate the relationship between TRPV4 channel, ESCRT-mediated membrane repair, and apigenin’s alleviation of APAP-induced pyroptosis and liver injury, we introduced the TRPV4 channel inhibitor HC067047, the calcium ion scavenger ethylenediaminetetraacetic acid (EDTA) and charged multivesicular body protein 4B (CHMP4B)-siRNA to detect the indicators related to pyroptosis and liver injury. Altogether, the study revealed that apigenin could activate TRPV4 channel to induce calcium influx, leading to ESCRT-Ⅲ expression and alleviating APAP-induced pyroptosis and liver injury. It provides new ideas and targets for using functional factors in food to improve APAP-induced liver injury.