This study was designed to investigate the effects of TNFSF14 on mitochondrial function in ischemia/reperfusion-induced acute kidney injury(I/R-AKI)and its mechanism.TNFSF14-/-and TNFSF14+/+mice underwent renal ischemia-reperfusion operation to establish I/R-AKI models,and their histopathology changes were compared by using Periodic Acid-Schiff stain,transmission electron microscopy.Immunohistochemistry(IHC)was used to detect levels of TNFSF14,HVEM,LT[3R,mitochondrial activity related proteins(Dpr1 and Mfn2)and inflammatory cells infiltration in kidney tissues of mice and relevant patients.In vitro cell experiments,immunofluorescence and immunoblotting were used to observe the effects of exogenous recombinant TNFSF14 factor on the damage and mitochondrial activity of renal tubular epithelial cell line HK-2 cells.Data showed that the expression of TNFSF14 and its receptors were significantly increased in kidney tissues of I/R-AKI mice and clinical human renal tissues of acute tubular injury.Compared with the sham group,I/R mice showed significantly higher levels of renal tubular injury score,inflammatory cells infiltration,cell apoptosis,mitochondrial damage,and Drp1 expression,while knocking out the TNFSF14 gene,the above indicators were significantly reduced.In vitro,exogenous TNFSF14 stimulation could aggravate the hypoxia-induced apoptosis and the decrease of mitochondrial membrane potential in HK-2 cells,while increasing phosphorylation of Drp1 at Se616 to promote its transfer from cytoplasm to mitochondria,leading to an abnormal increase in mitochondrial fission.In conclusions,TNFSF14 may mediate the pathological process of I/R-AKI by promoting mitochondrial damage.