Urinary exosomal microRNA-145-5p and microRNA-27a-3p act as noninvasive diagnostic biomarkers for diabetic kidney disease

BACKGROUND Diabetic kidney disease(DKD),characterized by increased urinary microalbumin levels and decreased renal function,is the primary cause of end-stage renal di-sease.Its pathological mechanisms are complicated and multifactorial;Therefore,sensitive and specific biomarkers are needed.Urinary exosome originate from diverse renal cells in nephron segments and partially mirror the pathological changes in the kidney.The microRNAs(miRNAs)in urinary exosome are remark-ably stable and highly tissue-specific for the kidney.METHODS Type 2 diabetic mellitus(T2DM)patients were recruited from the Second Hospital of Hebei Medical University and were divided into two groups:DM,diabetic pa-tients without albuminuria[urinary albumin to creatinine ratio(UACR)<30 mg/g]and DKD,diabetic patients with albuminuria(UACR≥30 mg/g).Healthy subjects were the normal control(NC)group.Urinary exosomal miR-145-5p,miR-27a-3p,and miR-29c-3p,were detected using real-time quantitative polymerase chain reaction.The correlation between exosomal miRNAs and the clinical in-dexes was evaluated.The diagnostic values of exosomal miR-145-5p and miR-27a-3p in DKD were determined using receiver operating characteristic(ROC)analysis.Biological functions of miR-145-5p were investigated by performing RESULTS Urinary exosomal expression of miR-145-5p and miR-27a-3p was more upregulated in the DKD group than in the DM group(miR-145-5p:4.54±1.45 vs 1.95±0.93,P<0.001;miR-27a-3p:2.33±0.79 vs 1.71±0.76,P<0.05)and the NC group(miR-145-5p:4.54±1.45 vs 1.55±0.83,P<0.001;miR-27a-3p:2.33±0.79 vs 1.10±0.51,P<0.001).The exosomal miR-145-5p and miR-27a-3p positively correlated with albuminuria and serum creatinine and negatively correlated with the estimated glomerular filtration rate.miR-27a-3p was also closely related to blood glucose,gly-cosylated hemoglobin A1c,and low-density lipoprotein cholesterol.ROC analysis revealed that miR-145-5p had a better area under the curve of 0.88[95%confidence interval(CI):0.784-0.985,P<0.0001]in diagnosing DKD than miR-27a-3p with 0.71(95%CI:0.547-0.871,P=0.0239).Bioinformatics analysis revealed that the target genes of miR-145-5p were located in the actin filament,cytoskeleton,and extracellular exosome and were involved in the pathological processes of DKD,including apoptosis,inflammation,and fibrosis.CONCLUSION Urinary exosomal miR-145-5p and miR-27a-3p may serve as novel noninvasive diagnostic biomarkers or promising therapeutic targets for DKD.

New insights into renal lipid dysmetabolism in diabetic kidney disease

Lipid dysmetabolism is one of the main features of diabetes mellitus and manifests by dyslipidemia as well as the ectopic accumulation of lipids in various tissues and organs,including the kidney.Research suggests that impaired cholesterol metabolism,increased lipid uptake or synthesis,increased fatty acid oxidation,lipid droplet accumulation and an imbalance in biologically active sphingolipids(such as ceramide,ceramide-1-phosphate and sphingosine-1-phosphate)contribute to the development of diabetic kidney disease(DKD).Currently,the literature suggests that both quality and quantity of lipids are associated with DKD and contribute to increased reactive oxygen species production,oxidative stress,inflammation,or cell death.Therefore,control of renal lipid dysmetabolism is a very important therapeutic goal,which needs to be archived.This article will review some of the recent advances leading to a better understanding of the mechanisms of dyslipidemia and the role of particular lipids and sphingolipids in DKD.

Yiqi Qingre Xiaozheng formula protects against diabetic nephropathy by restoring autophagy in mice

Objective:To evaluate the protective effect of Yiqi Qingre Xiaozheng formula(YQQRXZF)via the regulation of autophagy in diabetic nephropathy(DN)mice induced by injection of streptozotocin(STZ)after high fat diet(HFD).Methods:The composition of YQQRXZF was analyzed by high performance liquid chromatographyelectrospray ionization/mass spectrometry(HPLC-ESI/MSn).The DN model was induced by intraperitoneally injection of 50 mg/kg STZ within 5 days,followed by HFD feeding for 8 weeks in C57BL/6J mice.Mice were randomly separated into DN group,YQQRXZF group,irbesartan group,and control group.Blood glucose was calculated,and body weight was measured every 2 weeks.An enzyme-linked immunosorbent assay was used to measure the urinary albumin-to-creatinine ratio(uACR)before and after treatment,and the serum concentrations of total cholesterol(TC),low-density lipoprotein(LDL),triglycerides(TG),high-density lipoprotein(HDL),blood urea nitrogen(BUN),and serum creatinine(Scr)were measured.In addition,hematoxylin-eosin(H&E)staining,periodic acid-Schiff(PAS)staining,Masson's trichrome staining,and transmission electron microscopy(TEM)were used to observe pathological changes in renal tissue.Autophagy levels were determined by immunofluorescence staining.Results:In this study,21 dominant chemical constituents were identified in YQQRXZF.The treatment group reduced u ACR in a more significant way than the DN group(P=.018).The treatment group reduced TC,TG,and LDL concentrations after YQQRXFF treatment(P=.021,P=.014 and P=.026,respectively).H&E,PAS,and Masson staining showed that pathological damage to mice kidneys improved,the volume of renal glomeruli was reduced,and glomerular sclerosis and fibrosis were reduced.Immunofluorescence analysis revealed that expressions of LC3-Ⅱprotein increased in the treatment group(P=.013).In contrast,the protein expressions of P62 were reduced after treatment(P=.025).

Losartan Protects Podocytes against High Glucose-induced Injury by Inhibiting B7-1 Expression

The role of B7-1 in podocyte injury has received increasing attention.The aim of this study was to investigate whether losartan protects podocytes of patients with diabetic kidney disease(DKD)by regulating B7-1 and the underlying mechanisms.Rats with streptozotocin-induced DKD were treated with losartan for 8 weeks.Biochemical changes in blood and urine were analyzed.Kidneys were isolated for electron microscopy,immunofluorescence,real-time quantitative PCR(RT-PCR),and Western blot analysis.Immortalized mouse podocyte cells were cultured in normal or high glucose medium in the presence or absence of losartan for 48 h,and then the cells were collected for immunofluorescence,PCR,Western blotting and monolayer permeability detection.The phosphatidylinositol 3-kinase(PI3K)110a subunit and angiotensin II type 1 receptor(AT1R)plasmids were transfected into podocytes,respectively,and then Western blotting was performed to assess the expression of B7-1 protein.The results showed that losartan ameliorated podocyte structure and function in the rat model of DKD,and reduced the expression of B7-1 protein.Overexpression of PI3K 110a subunit in podocytes attenuated the inhibitory effect of losartan on B7-1 expression in high glucose-stimulated podocytes.The expression of B7-1 was significantly increased by overexpression of ATI R and significantly reduced by blocking PI3K 110a subunit.We conclude that losartan protects podocytes against high glucose-induced injury by inhibiting AT1R-mediated B7-1 expression.This effect is dependent on the AT1R-PI3K 110a subunit pathway.

Serum Levels of RBP4 Might Not Be Determined by Diabetes Mellitus but by Kidney Function and Renal Replacement Therapy

It has been reported that retinol-binding protein 4(RBP4) is associated to adiposity,insulin resistance,and type 2 diabetes.Meanwhile,circulating RBP4 levels are also affected by renal function.The aim of the present study is to investigate whether serum levels of RBP4 are primarily associated with different stages of chronic kidney disease(CKD) or type 2 diabetes,if there is more potential relevance between RBP4 and renal replacement therapy.The serum levels of RBP4 were assessed by commercial competitive enzyme-linked immunosorbent assay(ELISA)kit in 212 patients with the CKD stages 1—5 and in 24 healthy controls,while its correlation with clinical and metabolic parameters was analyzed.The serum level of RBP4 had a strong correlation with estimated glomerular filtration rate(e GFR)(P < 0.001).Stratified by e GFR and treatment,no more differences in RBP4 serum concentration were detected between type 2 diabetic and non-diabetic subjects [CKD stages 1—5,non-dialysis(ND),hemodialysis(HD) and peritoneal dialysis(PD);P > 0.05 for all].The elevation of RBP4 become higher in HD than in PD and ND in CKD5 patients(P = 0.008 and P = 0.04,respectively),while there was no significant difference between PD and ND groups.Multivariate linear regression analysis demonstrated three independent predictors of e GFR(β =-0.676,P < 0.001),C-reactive protein(CRP)(β =-0.573,P < 0.001) and creatine(β = 0.509,P = 0.024) in the study population.The study results demonstrated that the serum level of RBP4 was negatively related to the e GFR,whether diabetes mellitus(DM) affected the blood concentration of RBP4 or not.And the serum level of RBP4 exhibited significant difference in different renal replacement therapies.