The Molecular and Clinical Role of microRNA in Obesity Induced Nephropathy

On occurrence of chronic nephropathy, obesity is an important trigger factor. Obesity will also lead to a series of sequels such as diabetes, myocardial infarction. Obesity induced diabetes leading to diabetic nephropathy (DN) is an important subject of research of chronic renal failure in recent years. The aim of this study will evaluate the physiology role of microRNAs-494, small 22–25-nt-long noncoding RNA molecules, in obesity induced diabetic nephropathy and microRNA-494 may be used as a clinical nephropathy target in the future. From our previous study about miR-494 (published in JASN 2012) indicated that upregulation of miRNA-494 contributes to inflammatory or adhesion molecule-induced kidney injury after ischemia/reperfusion by inhibiting expression of ATF3. In addition, our preliminary study also shown that more serious phenomenon of obesity, high cholesterol, DM and diabetic nephropathy were observed in ATF3 knock out mice compared to WT mice when fed 40% high fat diet after 12 weeks (preliminary data Fig,1 Table.1). Furthermore, we also identified that miR-494 always was expressed at higher levels in the kidney of ATF3-/- mice compared to WT mice (preliminary data Fig 2). Subsequent computer analysis found that miR-494 specifically bound to the 3’UTR region of SIRT1/3 (preliminary data Fig 4) and inhibit transcriptional level of SIRT1 which play an important role in lipid metabolism (preliminary data Fig 5 and Fig 6). Therefore, we hypothesis that miR-494 not only play an important role in acute renal injury but play the other physiology role in diabetic nephropathy. Therefore, in this proposal, we aim to elucidate the following problems: Identification of miR-494 can act as a therapeutically target of diabetic nephropathy and evaluate the relationship between ATF3 and miR-494 . To reach our goal, three specific aims will be pursued Aim 1. To determine pathology or physiology role of miR-494 in diabetic nephropathy model in mice To characterize the pathophysiological role miRNA-494 in the process of diabetic nephropathy mice by overexpression or knock down of miR-494 (using sense or antisense lentiviral vector carrying microRNA-494 or transgenic mice of microRNA-494) (Preliminary data Fig 6) Aim 2: To characterize the signal transduction pathway and related genes be regulated by miR-494 after diabetic nephropathy To identify the molecular physiological role of miR 494 by ATF3 pathway resulting in diabetic nephropathy and clarify the relationship related to SIRT1 or PPARα by in vitro assay Aim 3: To identify miR-494 having potential as a biomarker or therapeutic target of diabetic nephropathy We will collect clinical blood or urine of patients with diabetic nephropathy to analysis the levels of miR-494. This study will provide new therapeutic and diagnostic targets, miR-494 for diabetic nephropathy. Simultaneously, more understanding about micro RAN in diabetic nephropathy will be done when this project is processing.