Project description:Diabetic kidney disease (DKD) appears heritable, suggesting genetic factors influence disease susceptibility. In our study, genes were mapped mediating early renal hypertrophic in response to diabetes. A survey of murine strains (N=15) was conducted to identify variation in kidney hypertrophy following diabetes induction. Mice with greater FVB/N and less C57BL/6 renal hypertrophy were crossed and diabetic F2 generation mice (n=534) were characterised. To confirm loci responsible for the renal hypertrophic response, diabetic congenic mice were generated by backcrossing FVB/N mice that conferred greater or C57BL/6 conferring lower risk into the reciprocal strain mice. Kidney weights of (FVB/N x C57BL/6) F2 diabetic mice were broadly distributed. Quantitative trait locus (QTL) analysis revealed that diabetic mice with kidney weights in the upper quartile shared alleles on chromosomes 6 and 12, with the FVB/N allele on chromosome 6 conferring greater susceptibility. On chromosome 12, C57BL/6 homozygotes were more significantly represented (LOD=3.8) conferring less susceptibility. The diabetic B6.Drc1/2f congenic strain developed kidney damage, while the reciprocal congenic, with FVB.Drc1/2b strain were protected. Microarray analysis identified differentially expressed genes between diabetic C57BL/6 and FVB/N mice. QTL mapping for early renal responses to diabetes identified two loci syntenic with regions identified for human diabetic kidney disease. Providing a new resource to study DKD.
Project description:The mechanism driving the remarkable ability of the remaining kidney to enlarge and increase its function following the removal of its contralateral pair remains elusive. To explore the pathways driving compensatory renal hypertrophy, comprehensive RNA-seq transcriptional studies were undertaken in the kidneys of C57BL/6 mice undergoing hypertrophy at 24, 48, and 72 hours following nephrectomy, and these results were compared with mice undergoing sham operations. In addition, mass spectrometry was carried out at 24 hours to examine changes in protein expression. Single-nuclei RNA-Seq was used to delineate bulk RNA-seq data into cell types at 24 hours post-nephrectomy. HK-2 renal tubular cells were examined for their ability to undergo hypertrophy in the presence of IGF-1 via the activation of cholesterol biosynthesis pathways. Bulk RNA-seq revealed substantial time-dependent enhancement of cholesterol biosynthesis pathways, increases in mitochondrial gene expression, and cell cycle perturbations. Single-nuclei RNA-Seq at 24 hours post-nephrectomy showed that Sterol Binding Protein 2 (SREBP2) activity increases in medullary thick ascending limb cells and, to a lesser extent, in proximal tubular cells, consistent with the role of promoting cholesterol synthesis. Furthermore, SREBP2 was found to regulate cell size following IGF-1 stimulation in HK-2 cells. There are early, cell-specific alterations in gene expression of cholesterol biosynthesis pathways, mitochondrial genes, and the cell cycle in kidneys undergoing compensatory hypertrophy. SREBP2 activity in the medullary thick ascending limb and, to a lesser extent, in proximal tubules may play a previously undescribed role in promoting cholesterol metabolism in the mechanism underlying compensatory renal hypertrophy.
Project description:We analyzed the effects of enarodustat (JTZ-951; HIF stabilizer) on renal energy metabolism in alloxan-induced diabetic mouse model. Transcriptome analysis of renal tissue revealed that genes related to fatty acid metabolism were upregulated in diabetes, whereas genes related to glucose metabolism were upregulated by enarodustat. In addition, genes related to amino acid metabolism were upregulated by diabetes and downregulated by enarodustat. Thus, HIF stabilization counteracts the renal energy metabolism alterations occurring in the early stages of diabetic kidney disease.
Project description:In diabetes, the kidney contributes to the development of diabetic hyperglycemia by increasing glucose reabsorption from the primary urine and by upregulating gluconeogenesis in the proximal tubule. However, these two processes are also controlled by the circadian clock, a mechanism that synchronizes a large number of specific renal functions with environmental daily cycles. Here, we investigated the (patho)physiological role of intrinsic renal tubule circadian clocks in the diabetic kidney. We demonstrate that diabetic mice devoid of the circadian transcriptional regulator BMAL1 in the renal tubule exhibit additional enhancement of renal gluconeogenesis, exacerbated hyperglycemia, increased glucosuria, polyuria and renal hypertrophy. Collectively, our results suggest that diabetic hyperglycemia can be worsened by dysfunction or misalignment of intrinsic renal circadian clocks.
Project description:Type 1 and type 2 diabetes (T1D and T2D) share pathophysiological characteristics, yet mechanistic links have remained elusive. T1D results from autoimmune destruction of pancreatic beta cells, while beta cell failure in T2D is delayed and progressive. Here we find a new genetic component of diabetes susceptibility in T1D non-obese diabetic (NOD) mice, identifying immune-independent beta cell fragility. Genetic variation in Xrcc4 and Glis3 alter the response of NOD beta cells to unfolded protein stress, enhancing the apoptotic and senescent fates. The same transcriptional relationships were observed in human islets, demonstrating the role for beta cell fragility in genetic predisposition to diabetes.
Project description:This research trial studies how well biospecimen collection works in identifying genetic changes in patients with breast, prostate, colorectal, liver, or kidney cancer or multiple myeloma undergoing surgery. Studying samples collected during surgery may add to the understanding of cancer by looking for the genetic changes that cause early cancer onset in people of certain racial and ethnic groups.
Project description:Angiotensin II is a key factor driving diabetic nephroparthy via ist AT1R. The role of ist AT2R in diabetic nephropathy is less known, however assumed to be renoprotective We used microarray data to study the effect of transgenic renal AT2R overexpression on the renal expression profile at early stages of diabetes