Hepatocyte nuclear factor 4alpha, a key factor for homeostasis, cell architecture, and barrier function of the adult intestinal epithelium.
Hepatocyte nuclear factor 4alpha (HNF-4alpha) is a transcription factor which is highly expressed in the intestinal epithelium from duodenum to colon and from crypt to villus. The homeostasis of this constantly renewing epithelium relies on an integrated control of proliferation, differentiation, and apoptosis, as well as on the functional architecture of the epithelial cells. In order to determine the consequences of HNF-4alpha loss in the adult intestinal epithelium, we used a tamoxifen-inducible Cre-loxP system to inactivate the Hnf-4a gene. In the intestines of adult mice, loss of HNF-4alpha led to an increased proliferation in crypts and to an increased expression of several genes controlled by the Wnt/beta-catenin system. This control of the Wnt/beta-catenin signaling pathway by HNF-4alpha was confirmed in vitro. Cell lineage was affected, as indicated by an increased number of goblet cells and an impairment of enterocyte and enteroendocrine cell maturation. In the absence of HNF-4alpha, cell-cell junctions were destabilized and paracellular intestinal permeability increased. Our results showed that HNF-4alpha modulates Wnt/beta-catenin signaling and controls intestinal epithelium homeostasis, cell function, and cell architecture. This study indicates that HNF-4alpha regulates the intestinal balance between proliferation and differentiation, and we hypothesize that it might act as a tumor suppressor.
Cattin
Anne-Laure
AL
Centre de Recherche des Cordeliers, Université Pierre et Marie Curie-Paris 6, UMRS 872, Paris F-75006, France.
Le Beyec
Johanne
J
Barreau
Frederick
F
Saint-Just
Susan
S
Houllier
Anne
A
Gonzalez
Frank J
FJ
Robine
Sylvie
S
Pinçon-Raymond
Martine
M
Cardot
Philippe
P
Lacasa
Michel
M
Ribeiro
Agnès
A
D000375:Aging / Q000502:physiology*; D000818:Animals; D019070:Cell Lineage; D049109:Cell Proliferation; D005786:Gene Expression Regulation; D051557:Hepatocyte Nuclear Factor 4 / Q000235:genetics / Q000378:metabolism*; D006706:Homeostasis; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000166:cytology* / Q000378:metabolism*; D051379:Mice; D008854:Microscopy, Electron; D015398:Signal Transduction; D019108:Tight Junctions / Q000378:metabolism / Q000648:ultrastructure; D051153:Wnt Proteins / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
D051557:Hepatocyte Nuclear Factor 4; C496593:Hnf4a protein, mouse; D051153:Wnt Proteins; D051176:beta Catenin