Diabetics now account for more than 40% of patients with end-stage renal disease (ESRD) and the number of diabetics with renal failure is expected to grow in the coming years. Diabetic nephropathy occurs following alterations in all structures of the kidney including blood vessels, interstitium, tubules and glomeruli. To better understand the cellular mechanisms of diabetic nephropathy we will perform proteomic analysis of renal tissue in two very different models of diabetes, 0VE26 transgenic mice and db/db mice, both of which display characteristics of human ESRD. The db/db model is initially insulin resistant and resembles human Type II diabetes. 0VE26 mice are severely hypoinsulinemic and thus are more similar to human Type I diabetics. The intent of this two-model analysis is to distinguish proteins critical to the process of diabetic nephropathy from proteins that are merely characteristic of insulin deficiency or insulin resistance. In an initial analysis of 0VE26 diabetic kidneys, we have identified 80 proteins in the murine renal proteome and demonstrate increased expression of three groups of proteins:1.) Serine protease inhibitors;2.) Cell cycle regulatory proteins;3.) Smooth muscle contractile elements. Increased expression of these proteins is consistent with previous studies that described increased matrix and endothelial proliferation in diabetic nephropathy. However, these preliminary data also identify potential novel mechanisms by which diabetic nephropathy progresses. This suggests the hypothesis to be tested that proteomic analysis can identify novel mechanisms of diabetic nephropathy. The Specific Aims that will address this hypothesis are to: 1. Produce proteome maps of kidneys from diabetic mice with insulin resistance and hypoinsulinemia. 2. Produce proteome maps of glomeruli from diabetic mice with insulin resistance and hypoinsulinemia. We will produce proteome maps using high-resolution two-dimensional gel electrophoresis. Extracted renal proteins from our hypoinsulinemic transgenic 0VE206 mouse model and the obese hyperinsulinemic db/db mouse model will be resolved by electrophoresis and identified by peptide mass fingerprinting. Comparison of the renal and glomerular proteome in hypoinsulinemic and insulin resistance diabetes to normal kidney may reveal candidates for disease mechanisms, therapeutic targets and biomarkers whose validity can be tested in further hypothesis driven research.
NIH ExPorter
NIH ExPorter