title: Novel GM1 ganglioside-like peptide mimics prevent the association of cholera toxin to human intestinal epithelial cells in vitro.
abstract: Cholera is an acute diarrheal disease caused by infection in the gastrointestinal tract by the gram-negative bacterium, Vibrio cholerae, and is a serious public health threat worldwide. There has not been any effective treatment for this infectious disease. Cholera toxin (CT), which is secreted by V. cholerae, can enter host cells by binding to GM1, a monosialoganglioside widely distributed on the plasma membrane surface of various animal epithelial cells. The present study was undertaken to generate peptides that are conformationally similar to the carbohydrate epitope of GM1 for use in the treatment of cholera and related bacterial infection. For this purpose, we used cholera toxin B (CTB) subunit to select CTB-binding peptides that structurally mimic GM1 from a dodecamer phage-display library. Six GM1-replica peptides were selected by biopanning based on CTB recognition. Five of the six peptides showed inhibitory activity for GM1 binding to CTB. To test the potential of employing the peptide mimics for intervening with the bacterial infection, those peptides were examined for their binding capacity, functional inhibitory activity and in vitro effects using a human intestinal epithelial cell line, Caco-2 cells. One of the peptides, P3 (IPQVWRDWFKLP), was most effective in inhibiting cellular uptake of CTB and suppressing CT-stimulated cyclic adenosine monophosphate production in the cells. Our results thus provide convincing evidence that GM1-replica peptides could serve as novel agents to block CTB binding on epithelial cells and prevent the ensuing physiological effects of CT.
authors.affiliation: Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA Charlie Norwood VA Medical Center, Augusta, GA 30904, USA ryu@gru.edu.
authors.forename: Robert K
authors.initials: RK
authors.lastname: Yu
authors.affiliation: Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA Charlie Norwood VA Medical Center, Augusta, GA 30904, USA.
authors.forename: Seigo
authors.initials: S
authors.lastname: Usuki
authors.affiliation: Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA Charlie Norwood VA Medical Center, Augusta, GA 30904, USA.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Itokazu
authors.affiliation: Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei 115, Taiwan.
authors.forename: Han-Chung
authors.initials: HC
authors.lastname: Wu
mesh_terms: D018938:Caco-2 Cells; D002772:Cholera Toxin / Q000378:metabolism*; D005677:G(M1) Ganglioside / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D018716:Molecular Mimicry; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D010446:Peptide Fragments; D005677:G(M1) Ganglioside; D002772:Cholera Toxin
keywords: GM1 ganglioside; bacterial infection; cAMP; cholera toxin; epithelial cell