Ulinastatin ameliorates podocyte ferroptosis via regulating miR-144-3p/SLC7A11 axis in acute kidney injury

Ferroptosis is a newly discovered form of cell death characterized by intracellular iron accumulation and subsequent lipid peroxidation, which has been identified in various pathological processes, such as acute kidney injury (AKI). Ulinastatin (UTI), known as an antioxidant and anti-inflammatory, has been reported to prevent kidney injury. Here, we investigated the protective effects of UTI on LPS-induced podocyte ferroptosis in vivo and in vitro. Conditionally immortalized mouse podocyte was exposed to LPS in the presence or absence of UTI in vitro for 48 h. The levels of reactive oxygen species (ROS) and intracellular Fe2+ were detected to value the effect of UTI treatment on the podocyte cell ferroptosis. We also evaluated the influence of UTI on kidney injury in vivo. LPS-induced mice were treated with vehicle or UTI at 50 U/g/d for 6 wk. We identified the important function of UTI in repressing ferroptosis and ameliorating podocyte injury. The treatment of UTI reduced accumulation of Fe2+ and lipid ROS in podocyte. The cell proliferation was induced by UTI compared with the LPS-treated group in vitro. UTI attenuated the podocyte cytoskeletal as well. Regarding the mechanism, we found that UTI upregulated solute carrier family 7 member 11 (SLC7A11) expression by reducing miR-144-3p in the cells. The overexpression of miR-144-3p blocked the protective role of UTI in podocyte ferroptosis. MiR-144-3p/SLC7A11 axis was involved in UTI-mediated podocyte cell proliferation in vitro. Furthermore, the treatment of UTI repressed podocyte injury and proteinuria in vivo, and the level of miR-144-3p was decreased while SLC7A11 expression was increased in comparison with the model mice. UTI prevents LPS-induced podocyte ferroptosis and subsequent renal dysfunction through miR-144-3p/SLC7A11 axis. These findings might provide a potential novel therapeutic option for AKI and other renal diseases affecting podocyte.