(taken from the application) Early-onset type 2 diabetes (MODYs) are monogenic forms of NIDDM characterized by an early disease-onset and by defects in insulin secretion. Mutations in th genes encoding HNF4theta and HNF1theta lead to two clinically indistinguishabl forms of NIDDM (MODY1 and MODY3, respectively). HNF4theta is an upstream regulator of HNF1theta and both genes define a transcriptional hierarchy believed to be essential for normal pancreatic Beta-cell function. We have shown that HNF3beta is a strong transactivator of HNF4theta gene expression an that HNF3theta is a negative regulator of HNF4theta and downstream target gene transcription. This shows that HNF3theta and HNF3beta have antagonistic transcriptional regulatory functions in vivo and suggests that HNF3beta is the master regulator of a balanced transcription factor hierarchy essential for normal pancreatic islet function. We now propose to study the role of the HNF-transcriptional regulatory network in pancreatic islets in normal and diabetic conditions. We propose to generate transgenic and knockout mouse models in which the expression of HNF3theta and HNF3beta is altered. We will study gene expression and pancreatic islet function in these mouse models. Thi will include histological analysis, insulin secretion tests of perifused islet and perfused pancreata as well as gene expression studies of the HNF3/HNF4/HNF cascade and downstream targets by quantification of steady state mRNA and protein levels. In a complimentary approach, we propose to study the expressio of HNFs and downstream targets in islets of a rodent model of NIDDM, the Zucke diabetic fatty (ZDF) male rat, during the progression from the prediabetic to the diabetic state. Since we have previously shown that HNF4theta is a key regulator of expression of glycolytic enzymes and GLUT2 we also propose to tes if there is a correlation between expression of HNFs, their target genes and glucose responsiveness of pancreatic Beta-cell lines. Finally, we propose to use visceral endoderm which was derived from HNF3beta and HNF4theta null ES cells as a model system to identify novel HNF3 and HNF4theta target genes. Any novel targets will be characterized and expression will be studied in the mutant mouse models. We hope that a comprehensive analysis of the HNF-transcriptional hierarchy and its regulation of downstream target gene expression will lead to a better pathomolecular understanding of pancreatic islet function. Novel target genes of this pathway can in future be tested for genetic linkage or genetic variation in other forms of MODY/NIDDM and may be potential targets for therapeutic intervention aimed at preserving or improvin Beta-cell function.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
3R01DK055033-02S1
Application #
6343995
Study Section
Special Emphasis Panel (ZDK1 (O1))
Program Officer
Sato, Sheryl M
Project Start
1998-09-30
Project End
2003-09-29
Budget Start
1999-09-30
Budget End
2000-09-29
Support Year
2
Fiscal Year
2000
Total Cost
$58,450
Indirect Cost
Name
Rockefeller University
Department
Internal Medicine/Medicine
Type
Other Domestic Higher Education
DUNS #
071037113
City
New York
State
NY
Country
United States
Zip Code
10065
Okada, Terumasa; Liew, Chong Wee; Hu, Jiang et al. (2007) Insulin receptors in beta-cells are critical for islet compensatory growth response to insulin resistance. Proc Natl Acad Sci U S A 104:8977-82
Wolfrum, Christian; Stoffel, Markus (2006) Coactivation of Foxa2 through Pgc-1beta promotes liver fatty acid oxidation and triglyceride/VLDL secretion. Cell Metab 3:99-110
Gao, Nan; Ishii, Kenichiro; Mirosevich, Janni et al. (2005) Forkhead box A1 regulates prostate ductal morphogenesis and promotes epithelial cell maturation. Development 132:3431-43
Kulkarni, Rohit N; Roper, Michael G; Dahlgren, Gabriella et al. (2004) Islet secretory defect in insulin receptor substrate 1 null mice is linked with reduced calcium signaling and expression of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA)-2b and -3. Diabetes 53:1517-25
Richter, Symi; Shih, David Q; Pearson, Ewan R et al. (2003) Regulation of apolipoprotein M gene expression by MODY3 gene hepatocyte nuclear factor-1alpha: haploinsufficiency is associated with reduced serum apolipoprotein M levels. Diabetes 52:2989-95
Wolfrum, Christian; Shih, David Q; Kuwajima, Satoru et al. (2003) Role of Foxa-2 in adipocyte metabolism and differentiation. J Clin Invest 112:345-56
Wolfrum, Christian; Besser, Daniel; Luca, Edlira et al. (2003) Insulin regulates the activity of forkhead transcription factor Hnf-3beta/Foxa-2 by Akt-mediated phosphorylation and nuclear/cytosolic localization. Proc Natl Acad Sci U S A 100:11624-9
Shih, David Q; Heimesaat, Markus; Kuwajima, Satoru et al. (2002) Profound defects in pancreatic beta-cell function in mice with combined heterozygous mutations in Pdx-1, Hnf-1alpha, and Hnf-3beta. Proc Natl Acad Sci U S A 99:3818-23
Boileau, Pascal; Wolfrum, Christian; Shih, David Q et al. (2002) Decreased glibenclamide uptake in hepatocytes of hepatocyte nuclear factor-1alpha-deficient mice: a mechanism for hypersensitivity to sulfonylurea therapy in patients with maturity-onset diabetes of the young, type 3 (MODY3). Diabetes 51 Suppl 3:S343-8
Shih, D Q; Screenan, S; Munoz, K N et al. (2001) Loss of HNF-1alpha function in mice leads to abnormal expression of genes involved in pancreatic islet development and metabolism. Diabetes 50:2472-80

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