The hepatocyte nuclear factor 4-alpha (HNF4) is a member of the nuclear receptor family of transcription factors. HNF4 controls genes in the liver and pancreas related to insulin and glucose production. Mutations in HNF4 cause Maturity Onset of Diabetes in Young 1 (MODY1), and hyperinsulinemic hypoglycemia (HH) in humans. Members of the nuclear receptor superfamily have a hydrophobic pocket inside their ligand binding domains (LBDs). Traditional drug screening strategies exploit these pockets, guided by known structures of isolated LBDs. The field has lacked high-resolution structures for full-length receptors, and therefore not considered the possibility of other druggable sites elsewhere in these proteins. We have obtained a complete crystal structure HNF4 homodimer, in a functionally revealing complex with its DNA response element. This structure unexpectedly reveals two sites at domain-domain junctions, where small molecules could bind. Our mutational studies, and previous knowledge of post-translational modifications, show these sites can allosterically regulate the DNA affinity of HNF4 . We propose a high-throughput screening campaign, together with confirmatory assays and mechanistic studies that exploit these new sites in HNF4 . Our goal is to identify potentiators of DNA binding that benefit certain MODY1 and HH disease populations where receptor-DNA binding is compromised by point mutations in HNF4 .

Public Health Relevance

We are proposing to carry out a comprehensive screen to identify small drug-like molecules that target a protein that regulates genes in the liver and pancreas. This protein, HNF4alpha, when mutated causes a human hereditary form of diabetes (MODY1), as well as a neonatal condition with low blood glucose and excess insulin. We are seeking small molecules that could help restore the lost function of the mutated HNF4alpha, and therefore provide benefit to these disease populations.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK097475-02
Application #
8589591
Study Section
Special Emphasis Panel (ZRG1-BST-F (50))
Program Officer
Margolis, Ronald N
Project Start
2012-12-05
Project End
2015-11-30
Budget Start
2013-12-01
Budget End
2014-11-30
Support Year
2
Fiscal Year
2014
Total Cost
$657,320
Indirect Cost
$320,233
Name
Sanford-Burnham Medical Research Institute
Department
Type
DUNS #
020520466
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Huang, Pengxiang; Chandra, Vikas; Rastinejad, Fraydoon (2014) Retinoic acid actions through mammalian nuclear receptors. Chem Rev 114:233-54
Rastinejad, Fraydoon; Huang, Pengxiang; Chandra, Vikas et al. (2013) Understanding nuclear receptor form and function using structural biology. J Mol Endocrinol 51:T1-T21
Chandra, Vikas; Huang, Pengxiang; Potluri, Nalini et al. (2013) Multidomain integration in the structure of the HNF-4? nuclear receptor complex. Nature 495:394-8