The hypothesis of this proposal is that following the attachment of enteropathogenic E. coli to intestinal cells, specific signal transduction pathways are activated which induce changes in intestinal epithelial function including active ion transport, barrier function and recruitment of inflammatory cells. The long-term objective is to understand the mechanisms by which EPEC induces alterations in host intestinal epithelial physiology.
Specific aims are: 1). To investigate the influence of EPEC on intestinal secretion and absorption. This will involve ion flux studies in Ussing chambers using T-84 cells. Preliminary data suggests that EPEC infection decreases the ISC, but increases chloride secretion. EPEC mutant strains, differing in expression of adherence or signaling factors, and enzyme inhibitors will be used to define the role of specific EPEC genetic factors and signal cascades. 2). To elucidate the role of IL-8 in EPEC-stimulated PMN transmigration and to determine the pathways through which EPEC regulates IL-8 expression. The investigators have demonstrated that epithelial cells secrete IL-8 in response to EPEC. EPEC regulation of the IL-8 gene transcription will be studied. Electrophoretic shift assays will examine the roles of transcription factors, in particular, NFKB. 3). To determine the effects of individual EPEC proteins (bundlin, intimin, eaeB) on specific epithelial functions and determine the signaling pathways involved. EPEC will be fractionated and the effects of these fractions on function will be examined. Specific proteins of interest will be purified and studied in functional assays.
|Nguyen, Mai; Rizvi, Jason; Hecht, Gail (2015) Expression of enteropathogenic Escherichia coli map is significantly different than that of other type III secreted effectors in vivo. Infect Immun 83:130-7|
|Battle, Scott E; Brady, Michael J; Vanaja, Sivapriya Kailasan et al. (2014) Actin pedestal formation by enterohemorrhagic Escherichia coli enhances bacterial host cell attachment and concomitant type III translocation. Infect Immun 82:3713-22|
|Glotfelty, Lila G; Zahs, Anita; Hodges, Kimberley et al. (2014) Enteropathogenic E. coli effectors EspG1/G2 disrupt microtubules, contribute to tight junction perturbation and inhibit restoration. Cell Microbiol 16:1767-83|
|Glotfelty, Lila G; Zahs, Anita; Iancu, Catalin et al. (2014) Microtubules are required for efficient epithelial tight junction homeostasis and restoration. Am J Physiol Cell Physiol 307:C245-54|
|Hodges, Kim; Hecht, Gail (2013) Bacterial infections of the small intestine. Curr Opin Gastroenterol 29:159-63|
|Glotfelty, Lila G; Hecht, Gail A (2012) Enteropathogenic E. coli effectors EspG1/G2 disrupt tight junctions: new roles and mechanisms. Ann N Y Acad Sci 1258:149-58|
|Annaba, Fadi; Sarwar, Zaheer; Gill, Ravinder K et al. (2012) Enteropathogenic Escherichia coli inhibits ileal sodium-dependent bile acid transporter ASBT. Am J Physiol Gastrointest Liver Physiol 302:G1216-22|
|Rhee, Ki-Jong; Cheng, Hao; Harris, Antoneicka et al. (2011) Determination of spatial and temporal colonization of enteropathogenic E. coli and enterohemorrhagic E. coli in mice using bioluminescent in vivo imaging. Gut Microbes 2:34-41|
|Vingadassalom, Didier; Campellone, Kenneth G; Brady, Michael J et al. (2010) Enterohemorrhagic E. coli requires N-WASP for efficient type III translocation but not for EspFU-mediated actin pedestal formation. PLoS Pathog 6:e1001056|
|Thanabalasuriar, Ajitha; Koutsouris, Athanasia; Weflen, Andrew et al. (2010) The bacterial virulence factor NleA is required for the disruption of intestinal tight junctions by enteropathogenic Escherichia coli. Cell Microbiol 12:31-41|
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