Project description:Analysis of gene expression in the liver of insulin-deficient mice regulated by icv leptin administration. Control group received icv PBS administration. Icv leptin administration ameliorates hyperglycemia in insulin-deficient mice. Our transcriptome data provides important aspects of the leptin’s anti-type 1 diabetes action.
Project description:Analysis of gene expression in the liver of insulin-deficient mice regulated by icv leptin administration. Control group received icv PBS administration. Icv leptin administration ameliorates hyperglycemia in insulin-deficient mice. Our transcriptome data provides important aspects of the leptin’s anti-type 1 diabetes action. Mice were harvested 10 days after icv leptin administration (25ng/0.11uL/hour). Liver samples were quickly removed, frozen in liquid nitrogen and subsequently stored at –80ºC. RNAs were extracted by Qiagen mRNA extract kits (RNeasy plus). gDNA was eliminated in this procedure by gDNA eliminator column, which is included in Qiagen mRNA extract kits. Genomics and Microarray Core Facility at UT-Southwestern (http://microarray.swmed.edu/) checked RNA quality with Bioanalyzer Chip and processed the samples for hybridization with Illumina Mouse-6 V2 BeadChip (Illumina Inc., San Diego, CA).
Project description:Leptin monotherapy (i.e. without the use of administered insulin and/or any other molecule) corrects ID-induced metabolic aberrancies and promotes survival of insulin deficient rodents. These results generated great interest in the possibility of treating insulin deficient patients with leptin and/or molecule(s) underlying its beneficial effects. Hence, with the goal of identifying circulating molecule(s) underlying the advantageous effect of leptin we performed quantitative proteomic analysis of plasma and identified S100A9 as a putative peripheral mediator of leptin action. Here, to identify circulating molecule(s) underlying the advantageous effect of leptin we compared the results obtained by quantitative proteomic analysis of plasma between 2 groups of mice: streptozotocin (STZ)-treated mice that underwent intracerebroventricular (icv) leptin treatment for 12 days (STZ-Leptin) and ii) STZ-treated mice that underwent icv leptin treatment for 10 days and were withdrawn from leptin treatment for the following two days (STZ-Leptin-STOP). STZ treatment led to a massive loss of pancreatic insulin-producing β-cells, diminished pancreatic Proinsulin mRNA level, and caused severe insulinopenia, and hyperglycemia. icv leptin administration normalized hyperglycemia. However, two days after leptin delivery was halted hyperglycemia reappeared. We hypothesized that change in plasmatic protein(s) content could underlie re-emergence of hyperglycemia following decrease of leptin action.
Project description:Leptin-responsive genes in the pathway of a leptin signal from the hypothalamus to the liver has not been detected. We used microarray to detailed the expression of gene in liver in the status of leptin deficiency, and leptin administration. As leptin deficient status, we use Lepmkyo/Lepmkyo rats or Lepob/Lepob mice and their wild type littermates.
Project description:Leptin-responsive genes in the pathway of a leptin signal from the hypothalamus to the liver has not been detected. We used microarray to detailed the expression of gene in liver in the status of leptin deficiency, and leptin administration. As leptin deficient status, we use Lepmkyo/Lepmkyo rats or Lepob/Lepob mice and their wild type littermates. Recombinant murine leptin (1 microg/mg) and saline was intraperitonealy administrated in 20 weeks old Lepob/Lepob mice and their control littermates, and 20 weeks old Lepmkyo/Lepmkyo rats and their control littermates. In order to detect the early response genes whose expression level were changed before the food intake and body weight would change, we took liver samples 6 hours after administration.
Project description:The purpose of this study was to identify leptin target genes and subsequent pathways correlated with leptin-mediated weight loss. We utilized the microarray technology to compare two types of leptin administration: one involving a direct stimulatory effect when administered peripherally (subcutaneous: SQ) and another that is indirect, involving a hypothalamic relay that suppresses food intake when leptin is administered centrally (intracerebroventricular: ICV). We report here the impact of central and peripheral administration of leptin on food intake, body weight and body fat composition in ob/ob mice. We also report hepatic gene expression changes caused by central versus peripheral leptin administration. Keywords: comparison Leptin deficient (ob/ob) mice were continuously administered leptin over 12-days using central (intracerebroventricular) or peripheral (subcutaneous) route of administration. Liver RNA was extracted and hybridized to Illumina microarrays and gene expression data was analyzed. The global gene expression profiles were compared after the central and peripheral leptin treatments in ob/ob mice and C57BL6 mice were used for the baseline gene expression.
Project description:Ob/ob mice were given 0, 12.5 or 25 ng/hr leptin through an osmotic pump. After 12 days, livers RNA was prepared and illumina microarrays were done. We tested whether leptin can ameliorate diabetes independent of weight loss by defining the lowest dose at which leptin treatment of ob/ob mice reduces plasma [glucose] and [insulin]. We found that a leptin dose of 12.5 ng/hour significantly lowers blood glucose and that 25 ng/hour of leptin normalizes plasma glucose and insulin without significantly reducing body weight, thus establishing that leptin exerts its most potent effects on glucose metabolism. To find possible mediators of this effect, we profiled liver mRNA using microarrays and identified IGF Binding Protein 2 as being regulated by leptin with a similarly high potency. Over-expression of IGFBP2 by an adenovirus reversed diabetes in insulin resistant ob/ob, Ay/a and diet-induced obese mice (DIO), as well as insulin deficient streptozotocin-treated mice. Hyperinsulinemic clamp studies showed a three-fold improvement in hepatic insulin sensitivity following IGFBP2 treatment in ob/ob mice. These results show that IGFBP2 can regulate glucose metabolism, a finding with potential implications for the pathogenesis and treatment of diabetes.
Project description:To describe the protein profile in hippocampus, colon and ileum tissue’ changing after the old faeces transplants, we adopted a quantitative label free proteomics approach.
Project description:In several models of obesity-induced diabetes, increased lipid accumulation in the liver has been associated with decreased diabetes susceptibility. For instance, deficiency in leptin receptor (db/db) leads to hyperphagia and obesity in both C57BL/6 and C57BLKS mice but, only on the C57BLKS background do the mice develop beta-cell loss leading to severe diabetes while C57BL/6 mice are relatively resistant. Liver triglyceride levels in the resistant C57BL/6 mice are 3 to 4 fold higher than in C57BLKS. To better understand the mechanisms contributing to metabolic dysfunction in obesity-induced diabetes, we used microarrays to comprehensively profile gene expression livers of F2 mice (B57BL/6 X DBA/2) deficient in leptin receptor (db/db) DBA/2J females were mated to C57BL/6 males carrying leptin receptor deficiency (db/+) and, F1 (db/+) offspring were interbred to produce F2 mice. Offspring deficient in leptin receptor (db/db) were fed on a chow diet until 5 weeks or 12 weeks of age and then euthanized for collection of liver tissue for RNA profiling along with other diabetes-related phenotypes.