The Role Of Selenoprotein T In Cisplatin-induced Acute Kidney Injury

Objective:Acute kidney injury?AKI?is a kind of clinical common acute syndrome caused by many factors.The selenoprotein family is well known for its antioxidant effects,and selenoprotein T?SelT?is one of the family without specific functions.Here we mainly examined whether SelT exerts an important role in cisplatin-induced AKI through suppression of oxidative stress and apoptosis.Methods:Using Western-Blot?WB?and immunohistochemistry?IHC?analysis to detect the basic expression of SelT in kidney tissues and cells,including human and murine.In vivo,C57BL/6 mice?8 weeks?were divided into four groups,including Control,AKI-1day,AKI-2days,and AKI-4days.The AKI mice models were established by intraperitoneal injection with cisplatin?25mg/ml?,while Control mice were injected with saline.And then all mice were measured with serum creatinine?Scr?and blood urine nitrogen?BUN?to verify whether the model was successful.In vitro,NRK-52e cells were treated with cisplatin?20?M?.Both kidney tissues and cells were collected to detect the protein expression of SelT,NGAL,and Caspase3 by WB to clarify whether SelT had taken part in the process of AKI.To further investigate the specific role of SelT and its probably mechanism,we transfected with lentivirus in NRK-52e cells to knockdown SelT and then treated with cisplatin.Then detecting the protein expression of SelT,PARP1,HO-1,Nox4,p22^phox,GRP78,Caspase12,CHOP,CytC,Caspase9,APAF1,AIF,and Caspase8.Detecting the activity of Caspase3 and the ratio of apoptosis by TUNEL assay to eliminate the role of SelT in the process of cell apoptosis.Oxidative stress-related indicators that reactive oxygen species?ROS?was assessed by immunofluorescence?IF?staining,while superoxide dismutase?SOD?,malondialdehyde?MDA?,and nitric oxide?NO?were measured by different biochemistry kits.Results:We found that SelT was highly expressed in kidney cortical tubules and lowly expressed in glomerulus in renal tissues of human,rat,and mouse,and also highly expressed in renal tubular cells from human and rat.In vivo,the level of Scr and BUN were markedly elevated,and the protein level of SelT was significantly decreased while the protein level of NGAL?Caspase3 were increased.In vitro,the protein level of SelT in NRK-52e cells treated with cisplatin?20?M?was decreased while the protein level of NGAL?Caspase3 were increased just as in vivo.And the ratio of apoptosis cells was obvious increased by flow cytometry.In addition,we discovered that after transfecting with lentivirus to knockdown the expression of SelT in NRK-52e cells,the protein expression of SelT and PARP-1 were obvious decreased,the protein expression of HO-1,Nox4,and p22^phox were signally increased,and the protein expression of GRP78,Caspase12,CHOP,CytC,Caspase9,APAF1,AIF,and Caspase8 were remains unchanged.The activity of Caspase-3 in cells was elevated as well as the ratio of apoptosis was increased by TUNEL assay.And the excessive activation of oxidative stress,measured with the decrease of SOD and the increase of MDA,NO,and ROS,was also triggered by the down-regulation of SelT.Conclusions:SelT exerts a protective role in cisplatin-induced AKI by suppression of oxidative stress and apoptosis.ROS,derived from the activation of Nox4,plays a crucial role to trigger oxidative stress and apoptosis in the process of AKI.