Abstract
The mechanism for activation of extracellular transglutaminase 2 (TG2) in the small intestine remains a fundamental mystery in our understanding of celiac sprue pathogenesis. Using the T84 human enterocytic cell line, we show that interferon-γ (IFN-γ), the predominant cytokine secreted by gluten-reactive T cells in the celiac intestine, activates extracellular TG2 in a dose-dependent manner. IFN-γ mediated activation of TG2 requires phosphatidylinositol-3-kinase (PI3K) activity, but is uninfluenced by a number of other kinases reported to be active in T84 cells. Pharmacological inhibition of PI3K in the presence of IFN-γ prevents TG2 activation as well as the previously characterized increase in transepithelial permeability. Our findings therefore establish PI3K as an attractive target for celiac sprue therapy, a possibility that is underscored by the encouraging safety profiles of several PI3K inhibitors undergoing human clinical trials.
Footnotes
This research was supported by the National Institutes of Health National Institute of Diabetes and Digestive and Kidney Diseases [Grant R01-DK063158] (to C. Kh.).
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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The online version of this article (available at http://jpet.aspetjournals.org) contains supplemental material.-
ABBREVIATIONS:
- TG2
- transglutaminase 2
- 5BP
- 5-biotinamido pentylamine
- IFN-γ
- interferon-γ
- PI3K
- phosphatidylinositol-3-kinase
- PBS
- phosphate-buffered saline
- HRP
- horseradish peroxidase
- ECL
- enhanced chemiluminescence
- MLCK
- myosin light chain kinase
- PIK
- permeant inhibitor of MLCK
- TFA
- trifluoroacetic acid
- HPLC
- high-performance liquid chromatography
- DMSO
- dimethyl sulfoxide
- ROCK
- Rho-associated protein kinase
- PKC
- protein kinase C
- ELISA
- enzyme-linked immunosorbent assay
- ERW1041E
- 2-[(3-bromo-4,5-dihydro-isoxazol-5-ylmethyl)-carbamoyl]-pyrrolidine-1-carboxylic acid quinolin-3-ylmethyl ester
- LY294002
- 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
- Glycyl-H-1152
- 2-amino-1-[(3S)-hexahydro-3-methyl-4-[(4-methyl-5-isoquinolinyl)sulfonyl]-1H-1,4-diazepin-1-yl]ethanone
- BEZ235
- 4-[2,3-dihydro-3-methyl-2-oxo-8-(3-quinolinyl)-1H-imidazo[4,5-c]quinolin-1-yl]-α,α-dimethyl-benzeneacetonitrile
- AS-252424
- 5-[5-(4-fluoro-2-hydroxy-phenyl)-furan-2-ylmethylene]-thiazolidine-2,4-dione
- IC-87114
- [(6-amino-9H-purin-9-yl)methyl]-5-methyl-3-(2-methylphenyl)-4(3H)-quinazolinone
- TGX-221
- 7-methyl-2-(morpholin-4-yl)-9-(1-phenylaminoethyl)-pyrido[1,2-a]-pyrimidin-4-one
- GDC0941
- 4-[2-(1H-indazol-4-yl)-6-[(4-methylsulfonylpiperazin-1-yl)methyl]thieno[3,2-d]pyrimidin-4-yl]morpholine.
- Received August 28, 2011.
- Accepted January 4, 2012.
- Copyright © 2012 by The American Society for Pharmacology and Experimental Therapeutics
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