No abstract

Hepatocyte proliferation is essential for recovering liver function after injury. In liver surgery, the mechanical stimulation induced by hemodynamic changes triggers vascular endothelial cells (VECs) to secrete large amounts of cytokines that enhance liver cell proliferation and play a pivotal role in liver regeneration. Piezo1, a critical mechanosensory ion channel, can detect and convert mechanical forces into chemical signals, importing external stimuli into cells and triggering downstream biological effects. However, the precise role of Piezo1 in VECs, especially in terms of mediating liver regeneration, remains unclear. Here, we report on a potential mechanism by which early changes in hepatic portal hemodynamics activate Piezo1 in VECs to promote hepatocyte proliferation during the process of liver regeneration induced by portal vein ligation (PVL) in rats. In this liver regeneration model, hepatocyte proliferation is mainly distributed in zone 1 and zone 2 of liver lobules at 24–48 h after surgery, while only a small number of Ki67-positive hepatocytes were observed in zone 3. Activation of Piezo1 promotes increased secretion of epiregulin (EREG) and amphiregulin (AREG) from VECs via the PKC/ERK1/2 axis, further activating epidermal growth factor receptors (EGFR) and ERK1/2 signals in hepatocytes and promoting proliferation. In addition, cytokines secreted by Piezo1-activated VECs can induce hepatocytes to undergo epithelial-mesenchymal transition (EMT). In the liver lobules, the expression of EGFR in hepatocytes of zone 1 and 2 is significantly higher than that in zone 3. The EGFR inhibitor gefitinib inhibits liver regeneration by suppressing the proliferation of hepatocytes in zones 1 and 2. Thus, activation of Piezo1 in VECs promotes hepatocyte proliferation, suggesting mechanical stimulation regulates hepatocyte proliferation in zones 1 and 2 during PVL-induced liver regeneration. These data provide a theoretical basis for the regulation of liver regeneration through chemical signals mediated by mechanical stimulation.