Foxa1 and Foxa2 maintain the metabolic and secretory features of the mature beta-cell.
Foxa1 and Foxa2 play both redundant and distinct roles in early pancreas development. We demonstrate here that inducible ablation of both transcription factors in mature mouse beta-cells leads to impaired glucose homeostasis and insulin secretion. The defects in both glucose-stimulated insulin secretion and intracellular calcium oscillation are more pronounced than those in beta-cells lacking only Foxa2. Unexpectedly, in contrast to the severe reduction of beta-cell-enriched factors contributing to metabolic and secretory pathways, expression of a large number of genes that are involved in neural differentiation and function is significantly elevated. We further demonstrate that expression of carbohydrate response element-binding protein (ChREBP or Mlxipl), an important transcriptional regulator of carbohydrate metabolism, is significantly affected in compound Foxa1/a2 mutant beta-cells. ChREBP expression is directly controlled by Foxa1 and Foxa2 in both the fetal endocrine pancreas as well as mature islets. These data demonstrate that Foxa1 and Foxa2 play crucial roles in the development and maintenance of beta-cell-specific secretory and metabolic pathways.
Gao
Nan
N
Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6145, USA.
Le Lay
John
J
Qin
Wei
W
Doliba
Nicolai
N
Schug
Jonathan
J
Fox
Alan J
AJ
Smirnova
Olga
O
Matschinsky
Franz M
FM
Kaestner
Klaus H
KH
D000818:Animals; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D015153:Blotting, Western; D047369:Chromatin Immunoprecipitation; D005838:Genotype; D051541:Hepatocyte Nuclear Factor 3-alpha / Q000235:genetics / Q000502:physiology*; D051542:Hepatocyte Nuclear Factor 3-beta / Q000235:genetics / Q000502:physiology*; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D008297:Male; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; C496500:Foxa1 protein, mouse; C496503:Foxa2 protein, mouse; D051541:Hepatocyte Nuclear Factor 3-alpha; C506001:Mlxipl protein, mouse; D009687:Nuclear Proteins; D014157:Transcription Factors; D051542:Hepatocyte Nuclear Factor 3-beta