Mesenchymal stem cells improve renal injury in diabetic rats by inhibiting CD103+DCs maturation to decline CD8 + T cell responses

Abstract

BackgroundDiabetic nephropathy (DN) caused by the consistent high levels of blood glucose often leads to end‐stage renal disease (ESRD). Studies have shown that CD103 + dendritic cells (DCs) display a pathogenic role in murine CKD via activation of CD8 + T cells in kidney. Mesenchymal stem cells (MSCs) were reported to be able to improve DN, affect maturation of DCs and inhibit activation and proliferation of T cells. Here we examined the effects of MSCs on DN and explored the underlying mechanism though CD103+ DCs in rat DN.Methods30 rats were randomly assigned into normal control group (NC, n=6, healthy rats without treatment); diabetic nephropathy group (DN, n=13, diabetic rats receiving injection of 0.5 ml 0.9% saline); BMSCs treatment group (DN‐MSCs, n=11, diabetic rats receiving injection of BMSCs). Male diabetic rats were intraperitoneally injected with 55 mg/kg body weight of streptozotocin(STZ, Sigma)once causing a fasting blood glucose (FBG) level ≥16.7 mM for 6 weeks. Then 1×107 cells/kg body weight MSCs were transplanted to rats via tail vein injection weekly for 6 weeks. At the 13th week, the rats were sacrificed and blood, urine, kidney were collected for further detection. The concentrations of FBG, blood urea nitrogen (BUN), urinary albumin, urinary creatinine and albumin to creatinine ratio (ACR) were determined. RT‐qPCR for IL‐1β, IL‐6, TNF‐α, BATF3, FLT‐3, ID2 was performed. Renal pathology (HE and Massion staining) and immunofluorescence (IF) for CD103, CD11c, CD8 were also performed. Fluorescence activated Cell Sorting (FACS) was performed to analysis or sort of kidney samples and to characterize the phenotype of renal mononuclear phagocytes (rMPs). A combination of markers including CD45, MHC‐II, lineage (lin) makers (CD3, CD19, T cell receptor [TCR]‐β, TCR‐γδ, and CD49b), CD11c, CD68, CD11b and CD103 was used.ResultDN rats showed dyslipidemia and increased 24‐h proteinuria. After six times BMSCs transplantation, BUN, urinary albumin, urinary creatinine and ACR were significantly lower than in rats with DN alone (p<0.01). In respect of renal pathology, DN rats showed increased inflammatory cell infiltration, renal tubular epithelial cells injury, tubular atrophy, interstitial expansion. BMSCs treatment downregulated the genes expression of inflammatory‐related cytokines such as IL‐6, TNF‐α and IL‐1β, and reduced the other symptoms of DN‐alone rats. Next we found that the number of kidney CD103 + DCs was significantly higher in DN than in normal rat. Kidney CD103 + DCs preferentially elicited CD8 + T cells to exacerbate kidney injury in DN rats. BMSCs transplantation Significantly downregulated the genes expression of transcription factors (Batf3) and growth factor receptors (Flt3) which are necessary for the development of CD103 + DCs. Furthermore, BMSCs transplantation impaired activation and proliferation of CD8 + T cells and prevented the exacerbation of kidney injury.ConclusionBMSCs were able to improve DN kidney injury through inhibiting CD103 + DCs maturation to decline CD8 + T cell responses.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.