The Protective Effect Of MYDGF On Podocyte Injury In Diabetic Nephropathy Mice And Its Possible Mechanism

BackgroundDiabetic nephropathy(DN)is one of the major microvascnlar complications of diabetes and has become the leading cause of end-stage renal disease.Podocytes are highly specialized,terminally differentiated cells that are integral components of the glomerular filtration barrier.Podocyte injury,such as alterations in the structures and functions of podocytes or loss of podocytes,is an early event in the development of DN,which affect the integrity of the filtration barrier and result in proteinuria and the progression of DN.Therefore,protecting podocytes from injury will be a promising therapeutic target for DN treatment.Myeloid-derived growth factor(MYDGF,also known as C19orfl 0)is a paracrine-acting protein derived from bone marrow-derived monocytes and macrophages.Our previous study found that MYDGF can promote intestinal glucagon-like peptide-1(GLP-1)production and improve glucose/lipid metabolism in type 2 diabetic mice.However,whether MYDGF also participate in the development of DN remains unknown.AimsThe aim of this study was to investigate the effects of MYDGF on podocyte injury in DN mice and its possible mechanisms.MethodsIn vivo experiments,MYDGF knockout(KO)and wild-type(WT)littermate mice were produced by mating MYDGF+/-breeders in C57BL/6 background purchased from shanghai Southern Model Biotechnology Company.Firstly,exploring the effect of MYDGF deficiency on proteinuria and podocyte injury in DN mice.Secondly,exploring the effect of exogenously supplemented MYDGF on proteinuria and podocyte injury in DN mice.At the end,urine were obtained to measure urinary albumin-to-creatinine ratio(UACR)by ELISA.For the morphometric assessment,kidney sections were stained with Periodic Acid-Schiff(PAS)kit.Moreover,the levels of key podocyte differentiation markers and related proteins in signal pathways were assessed by western blot.Additionally,Podocyte apoptosis were identified by immunofluorescen analysis,and podocytes morphometric assessments were performed by TEM.Thirdly,exploring the mechanisms that MYDGF exerts its effects on podocytes.Then siRNA/AKT intervene in kidney was used to explored the effects of MYDGF on proteinuria and podocyte injury in DN mice.In vitro experiments,conditionally immortalized mouse podocytes(MPC5)and glomeruli isolated from non-diabetic WT mice were treated with high glucose,and then exposed to 100ng/mL recombinant MYDGF(rMYDGF).At the terminal,apoptosis was measured by a Cell Lab QuantaTM SC Flow cytometer.The expression levels of proteins in podocytes with different treatments were assessed by western blot.ResultsIn vivo,MYDGF deficiency aggravated proteinuria,glomerular injury and podocytes injury in DN mice,and MYDGF restoration ameliorated proteinuria,glomerular injury and podocytes injury in DN mice.Podocytes from non-diabetic WT mice were used as in vitro system,and glomeruli isolated from non-diabetic WT mice were used as ex-vivo system.Results showed that rMYDGF can preserve the expression of nephrin in podocytes and decreased podocyte apoptosis.Mechanistically,the renoprotection of MYDGF may be attributed to the activation of the AKT/Bcl-2-associated death promoter(BAD)pathway.Conclusion and innovationOur data showed for the first time that MYDGF attenuate podocyte injury and proteinuria,and prevent the progression of DN,providing a novel strategy to the treatment for DN.