Trans‐Coumaryl acetate mediates GRK5/NF‐κB/Nrf2 signaling axis to ameliorate septic acute kidney injury

Trans-Coumaryl acetate (T-CA) is formed by the esterification of coumarin with acetic acid and belongs to the reprogramming products of aromatic amino acid and fatty acid metabolism. Currently, the impact of T-CA on the progression of septic acute kidney injury (SAKI) and its underlying mechanisms are not clear. A lipopolysaccharide (LPS)-treated HK-2 cell injury model was constructed, and a mouse SAKI model was constructed using a cecum ligation and puncture method. The impacts of T-CA on HK-2 cell survival and cytotoxicity were examined using a Cell Counting Kit-8 assay and lactate dehydrogenase kit. Inflammatory factors, Superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), reactive oxygen species (ROS), adenosine 5'-triphosphate (ATP), and mitochondrial membrane potential levels were measured using different kits. Apoptosis was identified using Hoechst 33258 and Terminal Deoxynucleotidyl Transferase mediated dUTP Nick-End Labeling (TUNEL) staining. Changes in renal histopathological injury and indicator protein expression in SAKI mice were observed by transmission electron microscopy and pathological staining. Western blot was used to assess the levels of G protein-coupled receptor kinase 5 (GRK5)/NF-κB/nuclear factor erythroid-2 related factor 2 (Nrf2) pathway, apoptosis and mitochondrial damage-related proteins. T-CA (2.5-20 μM) treatment for 24 h did not negatively impact HK-2 cell viability. In vitro, T-CA attenuated LPS-induced HK-2 cell injury while reducing cell mortality, inflammatory factor levels and oxidative stress injury. In vivo, intraperitoneal injection of 40 mg/kg of T-CA attenuated renal histopathological damage and apoptosis in SAKI mice. Additionally, T-CA reduced mitochondrial damage, MDA and ROS levels, and increased SOD, GSH, and ATP levels. T-CA down-regulated GRK5 protein, hindered NF-κB activation and activated Nrf2 pathway, and NF-κB activator Phorbol 12-myristate 13-acetate (PMA), Nrf2 inhibitor ML385 treatment and overexpression of GRK5 weakened the protective effect of T-CA in SAKI model. T-CA has the potential to improve SAKI by inhibiting mitochondrial dysfunction, increase cell viability and ameliorate renal injury through the GRK5/NF-κB/Nrf2 pathway in SAKI models.