title: Modulation of endogenous Cysteine Protease Inhibitor (ICP) 1 expression in Entamoeba histolytica affects amoebic adhesion to Extracellular Matrix proteins.
abstract: Entamoeba histolytica is an enteric tissue-invading protozoan parasite that causes amoebic colitis and occasionally liver abscess in humans. During tissue invasion, amoebic adhesion to host components is an important event for host cell death leading to successful invasion and infection. Among amoebic virulence factors, Gal/GalNAc lectin is known to be major adhesion factor to host cells. In this study, we investigated the role of amoebic secreted CP (Cysteine Proteases) in amoebic adhesion to extracellular matrix (ECM) protein using CP inhibitor and E. histolytica strains in which the endogenous inhibitor of cysteine protease (ICP) 1 gene was overexpressed (ICP1(+)) or repressed by antisense small RNA-mediated gene silencing (ICP1(-)). We found that pretreatment of wild-type amoebae with CP inhibitor E64, or thiol-group modifiers such as diamide and N-Ethylmaleimide resulted in a significant decrease in adhesion to laminin and collagen ECM proteins. Furthermore, ICP1(+) strain, with a reduction of secreted CP activity, exhibited reduced ability by 40% to adhere to laminin. In contrast, ICP1(-) strain, with a 1.9-fold increase of secreted CP activity, showed a two-fold increase in amoebic adherence to laminin compared to the control strain. In addition, total amount of secreted CP5 was decreased in ICP1(+) amoeba. Conversely, total amount of secreted CP1 and mature-form CP5 were increased in ICP1(-) amoeba. We also found that ICP1 was secreted into extracellular milieu. These results suggest that secreted CP activity by E. histolytica may be an important factor affecting adhesion to host proteins, and regulation of CP secretion by ICP plays a major role in pathogenesis. This study provides insight into the CP-mediated tissue pathogenesis in amoeba-invaded lesions during human amoebiasis.
authors.affiliation: Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea.
authors.forename: Young Ah
authors.initials: YA
authors.lastname: Lee
authors.affiliation: Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Saito-Nakano
authors.affiliation: Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea.
authors.forename: Kyeong Ah
authors.initials: KA
authors.lastname: Kim
authors.affiliation: Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea.
authors.forename: Arim
authors.initials: A
authors.lastname: Min
authors.affiliation: Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, Japan.
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Nozaki
authors.affiliation: Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea. Electronic address: myeong@yuhs.ac.
authors.forename: Myeong Heon
authors.initials: MH
authors.lastname: Shin
mesh_terms: D002448:Cell Adhesion; D003094:Collagen / Q000378:metabolism; D057056:Cysteine Proteases / Q000378:metabolism; D003958:Diamide / Q000494:pharmacology; D003978:Diazomethane / Q000031:analogs & derivatives* / Q000378:metabolism; D004151:Dipeptides / Q000235:genetics / Q000378:metabolism*; D004748:Entamoeba histolytica / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D007797:Laminin / Q000378:metabolism; D013439:Sulfhydryl Reagents / Q000494:pharmacology
chemical_list: D004151:Dipeptides; D004791:Enzyme Inhibitors; D016326:Extracellular Matrix Proteins; D007797:Laminin; D013439:Sulfhydryl Reagents; C431444:carbobenoxy-phenylalanyl-serine(O-benzyl)diazomethane; D003958:Diamide; D003978:Diazomethane; D003094:Collagen; D057056:Cysteine Proteases; D005033:Ethylmaleimide
keywords: Adhesion; Cysteine protease; Endogenous cysteine protease inhibitor (ICP); Entamoeba histolytica; Extracellular matrix