摘要Methotrexate(MTX)is frequently administered with the proton pump inhibitor omeprazole(OPZ)to relieve gastrointestinal adverse reactions of MTX,but the coadministration increases the risk of kidney injury.In this study,we investigated the mechanisms of combined OPZ and MTX-induced acute kidney injury(OPZ+MTX-AKI),which was induced in rats or mice by administration of OPZ plus MTX for 14 days.Analysis of the FAERS database revealed that AKI was the principal form of kidney injury when OPZ was administered with MTX.We showed that coadministration of OPZ and MTX to rats resulted in the development of AKI.We found that OPZ and MTX,by inhibiting the expression and activity of SERCA2 and IP3R,respectively,jointly disrupted Ca2+homeostasis,thereby causing cell damage.Transcriptomic analysis of clinical samples revealed that G protein-coupled receptor kinase 2(GRK2)served as a key protein in OPZ+MTX-AKI.In Grk2+/-mice and in mice with renal tubular epithelial cell(RTEC)-specific Grk2 knockdown,the manifestations of kidney injury,along with the levels of oxidative stress and apoptosis in the context of OPZ+MTX-AKI,were notably ameliorated.Conversely,in mice with RTEC-specific Grk2 overexpression,the kidney injury was markedly aggravated.Administration of GRK2 inhibitor CP-25(17.5,35,70mg/kg/d,i.g.)for 14 days dose-dependently alleviated OPZ+MTX-AKI in mice with RTEC-specific Grk2 overexpression.This study elucidates a novel mechanism of AKI induced by the combination of OPZ and MTX and identifies potential therapeutic targets.We provide an essential theoretical foundation for the rational clinical application of OPZ and MTX,as well as for prevention and treatment of the related kidney injury.