Premium
Role of Hypoxia‐Inducible Factor (HIF) on colonic goblet cell differentiation and function during mucosal healing
Author(s) -
Whitney Alyssa K,
Schwisow Kalya D,
Bayless Amanda J,
GoldenMason Lucy,
Mehta Gaurav,
Kuhn Kristine A,
Colgan Sean P,
Campbell Eric L
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.305.10
Subject(s) - goblet cell , mucin 2 , intestinal epithelium , hypoxia inducible factors , mucin , microbiology and biotechnology , epithelium , hypoxia (environmental) , biology , mucus , chemistry , gene expression , biochemistry , ecology , genetics , organic chemistry , oxygen , gene
Secreted mucus is essential for intestinal homeostasis, separating luminal bacteria from the colonic epithelium and preventing inappropriate inflammation. Depletion of the mucus‐secreting goblet cells has been shown in mice to lead to development of spontaneous colitis. Treatment of mice with a prolyl hydroxylase inhibitor (AKB‐4924) leads to stabilization of hypoxia inducible factor‐1 alpha (HIF‐1α) and ultimately regulation of hypoxia‐responsive genes that promote mucosal protection. Interestingly, goblet cell hyperplasia was observed following in vivo administration of AKB‐4924, which may account for the mucosal protection observed. Thus, we hypothesized epithelial stabilization of HIF‐1α leads to goblet cell differentiation and hyperplasia within the GI tract. Utilizing a three‐dimensional murine intestinal stem cell spheroid culture system, we were able to analyze the influence of HIF‐1α stabilization on epithelial differentiation in a physiologically relevant context. Spheroids were treated with a goblet cell promoting factor (a gamma secretase inhibitor, DBZ), AKB‐4924 or hypoxia and analyzed by qPCR for changes in differentiation markers for secretory goblet cells (i.e. Atoh1, Muc2, and SPDEF) or absorptive enterocytes (i.e. Hes1, ALPI, and Fabp2). Additionally, DBZ and AKB‐4924 treated organoids were visualized using immunofluorescence for changes in the expression of Muc2, the predominant colonic mucin. Contrary to our hypothesis, neither AKB‐4924 nor hypoxia resulted in the induction of goblet cell differentiation factors. Furthermore, mice lacking HIF‐1α in the intestinal epithelium (HIF‐1α fl/fl‐VillinCRE ) exhibited normal colonic goblet cell numbers. However, goblet cells in mice lacking epithelial HIF‐1α appeared less organized with mucin granules less uniform in size and more randomly dispersed, and have a significantly altered expression profile of both secreted and adherent mucins, indicating that epithelial HIF‐1α is involved in goblet cell function. Therefore, we conclude that AKB‐4924 does not act directly on the epithelium to promote epithelial goblet cell differentiation, however, epithelial HIF‐1α does alter goblet cell function, potentially regulating intestinal mucus layer, which may contribute to the mucosal‐protective role for stabilized HIF. Support or Funding Information R01 DK103639 from NIDDK, CDA from Crohn's and Colitis Foundation of America to E.L.C.