title: Entamoeba histolytica: lipid rafts are involved in adhesion of trophozoites to host extracellular matrix components.
abstract: Adhesion is an important virulence function for Entamoeba histolytica, the causative agent of amoebic dysentery. Lipid rafts, cholesterol-rich domains, function in compartmentalization of cellular processes. In E. histolytica, rafts participate in parasite-host cell interactions; however, their role in parasite-host extracellular matrix (ECM) interactions has not been explored. Disruption of rafts with a cholesterol extracting agent, methyl-beta-cyclodextrin (MbetaCD), resulted in inhibition of adhesion to collagen, and to a lesser extent, to fibronectin. Replenishment of cholesterol in MbetaCD-treated cells, using a lipoprotein-cholesterol concentrate, restored adhesion to collagen. Confocal microscopy revealed enrichment of rafts at parasite-ECM interfaces. A raft-resident adhesin, the galactose/N-acetylgalactosamine-inhibitable lectin, mediates interaction to host cells by binding to galactose or N-acetylgalactosamine moieties on host glycoproteins. In this study, galactose inhibited adhesion to collagen, but not to fibronectin. Together these data suggest that rafts participate in E. histolytica-ECM interactions and that raft-associated Gal/GalNAc lectin may serve as a collagen receptor.
authors.affiliation: Department of Biological Sciences, 132 Long Hall, Clemson University, Clemson, SC 29634, USA.
authors.forename: K
authors.initials: K
authors.lastname: Mittal
authors.forename: B H
authors.initials: BH
authors.lastname: Welter
authors.forename: L A
authors.initials: LA
authors.lastname: Temesvari
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002784:Cholesterol / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004748:Entamoeba histolytica / Q000737:chemistry* / Q000378:metabolism / Q000472:pathogenicity*; D004847:Epithelial Cells / Q000737:chemistry / Q000469:parasitology*; D005109:Extracellular Matrix / Q000737:chemistry / Q000469:parasitology*; D005353:Fibronectins / Q000378:metabolism; D005452:Fluoresceins / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000494:pharmacology; D005690:Galactose / Q000494:pharmacology; D006801:Humans; D037102:Lectins; D037181:Lectins, C-Type / Q000037:antagonists & inhibitors / Q000378:metabolism; D021962:Membrane Microdomains / Q000502:physiology*; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D018613:Microscopy, Confocal; D011956:Receptors, Cell Surface; D047392:beta-Cyclodextrins / Q000494:pharmacology
chemical_list: C023339:Clec10a protein, rat; D005353:Fibronectins; D005452:Fluoresceins; D005456:Fluorescent Dyes; D037102:Lectins; D037181:Lectins, C-Type; D008565:Membrane Proteins; D011956:Receptors, Cell Surface; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D003094:Collagen; D002784:Cholesterol; C007740:fluorexon; D005690:Galactose