Human Decay-Accelerating Factor and CEACAM Receptor-Mediated Internalization and Intracellular Lifestyle of Afa/Dr Diffusely Adhering Escherichia coli in Epithelial Cells

• Published in: Infection and Immunity 2009-01, Vol.77 (1), p.517-531
• Main Authors: Guignot, Julie, Hudault, Sylvie, Kansau, Imad, Chau, Ingrid, Servin, Alain L
• Format: Article
• Language: English
• Subjects: Adhesins; Adhesins, Escherichia coli - metabolism; Animals; Antigens, CD - metabolism; Bacterial Adhesion; Bacteriology; Biological and medical sciences; Carcinoembryonic antigen; Cathepsin D; CD55 Antigens - metabolism; CD63 antigen; CD66 antigen; CEACAM1 protein; Cell Adhesion Molecules - metabolism; Cellular Microbiology: Pathogen-Host Cell Molecular Interactions; CHO Cells; Cricetinae; Cricetulus; Cytoplasm - microbiology; decay-accelerating factor; endosomes; Epithelial cells; Epithelial Cells - microbiology; Escherichia coli; Escherichia coli - physiology; Fundamental and applied biological sciences. Psychology; GPI-Linked Proteins; HeLa Cells; Humans; Integrins; LAMP-1 protein; LAMP-2 protein; Microbial Viability; Microbiology; Miscellaneous; Receptors, Cell Surface - metabolism; Receptors, Cell Surface - physiology; Vacuoles; Vacuoles - microbiology
• ISSN: 0019-9567; 1098-5522
• DOI: 10.1128/IAI.00695-08

We used transfected epithelial CHO-B2 cells as a model to identify the mechanism mediating internalization of Afa/Dr diffusely adhering Escherichia coli. We provide evidence that neither the α5 or β1 integrin subunits nor α5β1 integrin functioned as a receptor mediating the adhesion and/or internalization of Dr or Afa-III fimbria-positive bacteria. We also demonstrated that (i) whether or not the AfaD or DraD invasin subunits were present, there was no difference in the cell association and entry of bacteria and that (ii) DraE or AfaE-III adhesin subunits are necessary and sufficient to promote the receptor-mediated bacterial internalization into epithelial cells expressing human decay-accelerating factor (DAF), CEACAM1, CEA, or CEACAM6. Internalization of Dr fimbria-positive E. coli within CHO-DAF, CHO-CEACAM1, CHO-CEA, or CHO-CEACAM6 cells occurs through a microfilament-independent, microtubule-dependent, and lipid raft-dependent mechanism. Wild-type Dr fimbria-positive bacteria survived better within cells expressing DAF than bacteria internalized within CHO-CEACAM1, CHO-CEA, or CHO-CEACAM6 cells. In DAF-positive cells, internalized Dr fimbria-positive bacteria were located in vacuoles that contained more than one bacterium, displaying some of the features of late endosomes, including the presence of Lamp-1 and Lamp-2, and some of the features of CD63 proteins, but not of cathepsin D, and were acidic. No interaction between Dr fimbria-positive-bacterium-containing vacuoles and the autophagic pathway was observed.