Enterohemorrhagic E. coli (EHEC) is a food borne pathogen that causes a range of symptoms including non- bloody diarrhea and hemorrhagic colitis. While the most serious manifestations of EHEC infection are attributed to Shiga-like toxins, other EHEC virulence factors are encoded in a pathogenicity island, the locus of enterocyte effacement (LEE). LEE-encoded proteins include structural components of a type III secretion system (TTSS) and effector proteins delivered into host cells by TTSS. The effector protein Tir (translocated intimin receptor), following translocation into host cells, inserts into the cell membrane and engages the bacterial surface adhesin, intimin. In concert with the non-LEE secreted protein UEspF, Tir recruits the host protein N-WASP, which nucleates actin polymerization resulting in a pedestal-like structure below attached bacteria. Deletion of UespF, but not the LEE-encoded homolog espF, abrogates EHEC pedestal formation. EPEC and EHEC disrupt tight junctions (TJ). In EPEC, this is mediated partly by the LEE-encoded protein EspF, yet deletion of espFEHEC, which displays sequence similarity to espFEPEC, has no effect on EHEC-induced barrier function alteration. Deletion of UespF, however, attenuates the effects of EHEC on TJs, suggesting a direct role for UEspF in TJ disruption or that UEspF-mediated pedestal formation promotes barrier disruption. EspFEHEC and UEspF contain proline-rich domains (PRDs) allowing interaction with host proteins. We have identified SNX9 as a binding partner of EspF and UEspF via PRDs;these proteins also house the 14-3-3 consensus binding sequence. We will investigate the role of these interactions in the disruption of intestinal barrier function. Both pathogens also induce myosin light chain (MLC) phosphorylation, which contributes to barrier disruption. The EHEC effector responsible for increasing MLC phosphorylation has not been identified. The overall hypothesis of this proposal, therefore, is that the roles of UEspF in pedestal formation and TJ disruption are linked and that the full effect of EHEC on host epithelial barrier function requires the concerted action of several effectors.
The Specific Aims that will address this hypothesis are: 1. To define the role of EHEC-induced pedestal formation in intestinal epithelial tight junction (TJ) disruption using in vitro and in vivo models. 2. To characterize the host cell interaction partners of EspF/UEspF and define their roles in EHEC-induced barrier function alteration. 3. To identify the signaling pathway(s) responsible for EHEC-induced phosphorylation of myosin light chain (MLC) and the effector(s) involved.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
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Special Emphasis Panel (ZRG1-DIG-C (02))
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Grey, Michael J
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University of Illinois at Chicago
Internal Medicine/Medicine
Schools of Medicine
United States
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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
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
Royan, Sandhya V; Jones, Rheinallt M; Koutsouris, Athanasia et al. (2010) Enteropathogenic E. coli non-LEE encoded effectors NleH1 and NleH2 attenuate NF-ýýB activation. Mol Microbiol 78:1232-45
Weflen, Andrew W; Alto, Neal M; Viswanathan, Virinchipuram K et al. (2010) E. coli secreted protein F promotes EPEC invasion of intestinal epithelial cells via an SNX9-dependent mechanism. Cell Microbiol 12:919-29

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