Enterohemorrhagic E. coli alters murine intestinal epithelial tight junction protein expression and barrier function in a Shiga toxin independent manner

• Published in: Laboratory investigation Vol. 90; no. 8; pp. 1152 - 1168
• Main Authors: Roxas, Jennifer L, Koutsouris, Athanasia, Bellmeyer, Amy, Tesfay, Samuel, Royan, Sandhya, Falzari, Kanakeshwari, Harris, Antoneicka, Cheng, Hao, Rhee, Ki Jong, Hecht, Gail
• Format: Journal Article
• Language: English
• Published: New York Elsevier Inc 01-08-2010; Nature Publishing Group US; Nature Publishing Group
• Subjects: 631/80/79/1987; 692/698/2741; 692/699/255/1318; Animals; Biological and medical sciences; Biotechnology; claudin-2; Claudin-3; Colon - metabolism; Colon - microbiology; Dextrans; Diarrhea; EHEC; Enterohemorrhagic Escherichia coli; Escherichia coli; Escherichia coli - genetics; Escherichia coli - metabolism; Escherichia coli Infections - metabolism; Escherichia coli Infections - microbiology; Fluorescein-5-isothiocyanate - analogs & derivatives; Fundamental and applied biological sciences. Psychology; Hemolytic-Uremic Syndrome; Ileum - metabolism; Intestinal Mucosa - metabolism; Intestinal Mucosa - microbiology; Investigative techniques, diagnostic techniques (general aspects); Laboratory Medicine; Male; Medical sciences; Medicine; Medicine & Public Health; Membrane Proteins - genetics; Membrane Proteins - metabolism; Mice; Mice, Inbred C57BL; microvilli effacement; Occludin; Pathology; Permeability; research-article; Shiga Toxin - metabolism; Tight Junctions - metabolism; Tight Junctions - microbiology; Tight Junctions - physiology; transmucosal electrical resistance; EHEC; occludin; microvilli effacement; claudin-3; claudin-2; mice; transmucosal electrical resistance; Biotechnology; Membrane protein; Barrier function; Escherichia coli; Cell junction; Occludin; Clinical biology; Bacteria; Shiga like toxin; Enterobacteriaceae; Digestive system; Rodentia; Gut; Microvilli; Resistance; Vertebrata; Mammalia; Mouse; Animal; Claudin; Tight junction
• ISSN: 0023-6837; 1530-0307
• DOI: 10.1038/labinvest.2010.91

Shiga toxin (Stx) is implicated in the development of hemorrhagic colitis and hemolytic-uremic syndrome, but early symptoms of enterohemorrhagic Escherichia coli (EHEC) infection such as nonbloody diarrhea may be Stx independent. In this study, we defined the effects of EHEC, in the absence of Stx, on the intestinal epithelium using a murine model. EHEC colonization of intestines from two groups of antibiotic-free and streptomycin-treated C57Bl/6J mice were characterized and compared. EHEC colonized the cecum and colon more efficiently than the ileum in both groups; however, greater amounts of tissue-associated EHEC were detected in streptomycin-pretreated mice. Imaging of intestinal tissues of mice infected with bioluminescent EHEC further confirmed tight association of the bacteria with the cecum and colon. Greater numbers of EHEC were also cultured from stool samples obtained from streptomycin-pretreated mice, as compared with those that received no antibiotics. Transmission electron microscopy shows that EHEC infection leads to microvillous effacement of mouse colonocytes. Hematoxylin and eosin staining of the colonic tissues of infected mice revealed a slight increase in the number of lamina propria polymorphonuclear leukocytes. Transmucosal electrical resistance, a measure of epithelial barrier function, was reduced in the colonic tissues of infected animals. Increased mucosal permeability to 4- kDa FITC-dextran was also observed in the colonic tissues of infected mice. Immunofluorescence microscopy showed that EHEC infection resulted in redistribution of the tight junction (TJ) proteins occludin and claudin-3 and increased the expression of claudin-2, whereas ZO-1 localization remained unaltered. Quantitative real-time PCR showed that EHEC altered mRNA transcription of OCLN, CLDN2, and CLDN3. Most notably, claudin-2 expression was significantly increased and correlated with increased intestinal permeability. Our data indicate that C57Bl/6J mice serve as an in vivo model to study the physiological effects of EHEC infection on the intestinal epithelium and suggest that altered transcription of TJ proteins has a role in the increase in intestinal permeability.