High Glucose Aggravates Lipotoxic Renal Injury By Circ8411/miR-23a-5p/ABCA1 Induced GEnCs Pyrotosis And Protective Role Of GLP-1RA

Objective With the increasing prevalence of diabetes,diabetic kidney disease(DKD)has become leading cause of chronic kidney disease.DKD is a common complication of diabetes.Diabetic with hyperlipidemia have a more rapid renal disease progression and a higher incidence of end-stage renal disease than patients with diabetes or hyperlipidemia.Glucolipotoxicity has a synergistic effect on renal injury.What role does high glucose play in lipotoxicity-induced renal injury is unknown.Our previous research found high glucose aggravated cholesterol accumulation in(glomerular endothelial cell)GEnCs by LXRs/Lnc RNAOR13C9/ABCA1.We wanted to explore the mechanism of high glucose on lipotoxic renal injury and role of GLP-1receptor agonist(GLP-1RA)in it.Methods:1.CCK8,Oil red O staining,total cholesterol quantitative test detected cell viability and cholesterol accumulation in GEnCs treated with different cholesterol concentrations at different times.GEnCs were divided into low glucose group(LG),high glucose group(HG),high cholesterol group(HC),HG and HC group(HG+HC).The ABCA1 were detected by RT-q PCR and Western Blotting.2.Hoechst 33342/PI fluorescence staining and LDH activity assay kit were used to detect pyroptosis.Expression of caspase-1,GSDMD,IL-1β were detected.ABCA1 expression was inhibited by DIDS,and pyroptosis were detected.3.The circ RNA microarray and RT-q PCR were used to find circ RNA(circ8411)downregulated in the HG+HC compared with HC.The circ8411 siRNAs,plasmids and empty vectors were transfected into the cells.4.Bioinformatics analysis,rescue experiments,luciferase assay and UVI3003 were used to find a miRNA(miR-23a-5p)and a transcription factor(RXRα)of circ8411.5.Effects of GLP-1RA on cholesterol accumulation,pyroptosis and regulatory mechanism in GEnCs at HG+HC.6.C57BL/6J,Apo E-/-mice were divided into control(WT-NC),diabetes(WT-NC),hypercholesterolemia(Apo E-/-),diabetes with hypercholesterolemia(Apo E-/-DM),Apo E-/-DM treated with GLP-1RA.TG,TC,LDL-C,HDL-C,Scr,BUN,UTP,circ8411,ABCA1,cholesterol accumulation and pyroptosis were detected.Results:1.High cholesterol decreased cells viability.The cholesterol accumulation in cells grown in high cholesterol increased in a concentration dependent manner.2.Cholesterol accumulation and pyroptosis of GEnCs in HG+HC was higher than HC.ABCA1 in HG+HC were downregulated,compared with HC.ABCA1 expression was inhibited by DIDS,resulting in pyroptosis.3.Circ8411 knockdown decreased ABCA1,increased cholesterol accumulation and pyroptosis.Circ8411 was a target of miR-23a-5p.Inhibition of RXRα caused cicr8411 and ABCA1 decreased.4.GLP-1RA could increase cells activity,RXRα,circ8411,ABCA1 expression and reduce cholesterol accumulation and pyroptosis.5.The blood glucose in Apo E-/-DM was higher than that in the Apo E-/-.Compared with WT-NC,TC,LDL-c,Scr,BUN and UTP in the WT-DM,Apo E-/-and Apo E-/-DM increased,while HDL-c was decreased.There were renal mesangial hyperplasia and renal tubular vacuolar degeneration in Apo E-/-DM.GLP-1RA could improve the dyslipidemia and damage of renal structure and function.6.The ABCA1 expression decreasing,cholesterol accumulationin and pyroptosis aggravating in renal tissues of Apo E-/-DM compared with the Apo E-/-.GLP-1RA increased ABCA1 and alleviated renal cholesterol accumulation and pyroptosis.Conclusion:High glucose decreases circ8411 via inhibiting RXRα,resulting in ABCA1 decreased,cholesterol accumulation and cell pyroptosis.In this study,we found that RXRα/circ8411/miR-23a-5p/ABCA1 is one of the mechanisms by which high glucose promotes lipotoxic renal injury,and is expected to be a new target for treatment of renal damage in patients with diabetes and hypercholesterolemia.Moreover,GLP-1RA may improve renal injury through this pathway.