Role Of Long Noncoding RNAs In Septic Acute Kidney Injury

Role of long noncoding RNAs in septic acute kidney injury OBJECTIVE: 1.The aim of this study was to investigate aberrantly expressed circulating lnc RNAs in septic AKI patients and interrogate potential molecular mechanisms of septic AKI from lnc RNA level.2.To evaluate the changes and value of kidney injury molecule-1(KIM-1),neutrophil gelatinase-associated lipocalin(NGAL)and Interleukin-6(IL-6)in bloodstream infection with injection of different strains for septic acute kidney injury.3.To monitor mi R-4321 and mi R-4270 expression levels at different interval of septic AKI.METHODS: 1.By applying gene chip technology,blood samples from septic AKI patients(n=3)and healthy volunteers(n=3)were withdrawn and lnc RNAs detected.2.Forty five adult male specific pathogen-free SD rats were randomly divided into three groups(E.coli: n=15;SA:n=15;Control group:n=15).Rats were treated with tail vein injection of Suspended Escherichia coli(E.coli),Staphylococcus aureus(S.aureus)1.5x 10(8)CFU/ml at a dose of 0.1 m L/100 g,Control rats underwent the same procedure,but were injected with normal saline.The blood samples and the kidney cortex tissues were taken at the time points of 6h,12 h,24h,48 h and 72 h after injection.The plasma samples were obtained for serum creatinine(Scr),blood urea nitrogen(BUN),blood kidney injury molecule-1(p KIM-1),plasma neutrophil gelatinase-associated lipocalin(p NGAL)and Interleukin-6 detection.The p KIM-1,p NGAL and IL-6 levels of blood were detected by ELISA.Pathologiesl examinations were performed to check the differences between the three groups.3.A modified quantitative RT-PCR was used to quantitate the mi R-4321 and mi R-4270 expression of renal tissue in E.coli group.RESULTS: 1.We finally determined 30,586 differentially expressed human lnc RNAs and 26,109 differentially expressed m RNAs(?2-fold change).Among them,5361 upand 5928 downregulated lnc RNAs compared with those in the control group.The results were analyzed by gene ontology(GO)and KEGG pathway analysis.GO analysis indicated that dysregulated transcripts were associated with cell differentiation,immune system development,toll-like receptor 4 signaling pathway,inflammatory response,Wnt receptor signaling pathway,etc.Pathway analysis indicated that 33 pathways corresponded to up-regulated transcripts and 17 pathways corresponded to downregulated transcripts.Pathway analysis showed that a significant enrichment in several pathways related to inflammatory response such as MAPK signaling pathway,NF-kappa B signaling pathway,TGF-beta signaling pathway,PI3K-Akt signaling pathway,Wnt signaling pathway,calcium signaling pathway,etc.2.p KIM-1,p NGAL and IL-6 levels in E.coli group and S.aureus group reached the peak at 6 h of injection synchronously were significantly higher than those of the Control group at 6h,12 h,24h,48h(P<0.01).p KIM-1,p NGAL and IL-6 levels in E.coli group were significantly higher than those of the S.aureus group at 6h,12 h,24h,48h(P<0.05).Scr and BUN levels began to rise after 6h of injection and reached the peak at 48 h synchronously,which were 1ater than the p KIM-1 and p NGAL.The pathological examination showed that there was less epithelial injury at 12 h,24h,48 h in S.aureus group.3.In E.coli group,mi R-4321 and mi R-4270 showed an initial decrease at 6h,which reached the peak at 24 h of injection.At 48 h,the expression began to decrease compared with that at 24 h.With the extension of time of disease,the level of mi R-4321 at 72 h was significantly higher than those at 6h,12 h,24h,48h(P<0.05).CONCLUSION: 1.Our results demonstrated that the alteration of circulating lnc RNAs may be closely involved in the pathogenesis of septic AKI and may be used as novel candidate biomarkers for the clinical diagnosis of septic AKI and potential targets for further therapy.2.The levels of p KIM-1 and p NGAL can timely and accurately reflect the changes in renal function,higher p KIM-1,p NGAL and IL-6 levels are found in E.coli group and it may pay a role in discriminating between the E.coli and S.aureus in bloodstream infection.3.The level of mi R-4321 and mi R-4270 in septic AKI differentially expressed at different time points in E.coli group.