The protective effect of homoplantaginin on AP cells is regulated by the circDNMT3B/miR-20b-5p/SLC7A11 axis through the modulation of ferroptosis

Background: Acute pancreatitis (AP) is a common and potentially life-threatening inflammatory disease of the pancreas, with 20% of patients progressing to severe acute pancreatitis（SAP）, which is associated with a high mortality rate. Cellular ferroptosis has been implicated in the pathogenesis of AP; however, the specific mechanisms remain unclear. Objective: This study aims to elucidate the molecular mechanisms by which homoplantaginin（Hom）regulates ferroptosis in AP cells through the circDNMT3B/miR-20b-5p/SLC7A11 axis. Methods: An in vitro model of AP was established using the mouse pancreatic acinar cell line 266-6, induced by caerulein. The biological characteristics of caerulein-treated 266-6 cells were assessed through Cell Counting Kit-8 (CCK-8) assays, flow cytometry, ELISA, qPCR, and Western blot analysis. The circDNMT3B inhibitor was transfected into cells to achieve gene knockdown of circDNMT3B, and the results were compared with those of the blank control group. Results: In comparison with the blank control group, it was observed that the treatment with Hom resulted in a significant decrease in the levels of IL-1β, IL-18, MDA, PTGS2, and ACSL4 (all p < 0.01) as well as Fe²⁺ content and GSH (both p < 0.05) in the AP cells. Conversely, the expression levels of SLC7A11 and GPX4 were significantly elevated (both p < 0.01). It was further demonstrated that Hom treatment downregulated the expression of miR-20b-5p (p < 0.01) while upregulating the expression of circDNMT3B (p < 0.001) and Slc7a11 (p < 0.01). Additionally, it was found that the knockdown of the circDNMT3B gene led to a significant increase in the inflammatory levels of AP cells (p < 0.05), an elevation in amylase content (p < 0.01), a reduction in apoptosis of AP cells (p < 0.001), and an enhancement of ferroptosis in the cells. Conclusion: Hom is able to upregulate the expression of circDNMT3B and downregulate the expression of miR-20b-5p through the circDNMT3B/miR-20b-5p/SLC7A11 axis, thereby resulting in the increased expression of SLC7A11 and GPX4 in cells. This modulation is associated with the regulation of ferroptosis and a reduction in the inflammatory levels of acute pancreatitis. Furthermore, the circDNMT3B gene is suggested to play a protective role in the context of AP cell injury.