Myosin II and the Gal-GalNAc lectin play a crucial role in tissue invasion by Entamoeba histolytica

Abstract

SummaryEntamoeba histolytica is the human parasite responsible of amoebiasis, during which highly motile trophozoites invade the intestinal epithelium leading to amoebic colitis, and disseminate via the blood circulation causing liver abscesses. The invasive process, central to the pathogenesis, is known to be driven by parasites motility. To investigate molecules responsible for in vivo motion, we performed a high resolution dynamic imaging analysis using two-photon laser scanning microscopy. Image analysis of the parasites during invasion of Caco-2 cell monolayers, an enterocyte-like model, and hamster liver shows that E. histolytica undergoes non-Brownian motion. However, studies of movements of parasite strains dominant negative for myosin II, a central component of the cytoskeleton, and for Gal-GalNAc lectin, a major adhesion molecule, indicate that myosin II is essential for E. histolytica intercellular motility through intestinal cell monolayers and for its motility in liver. In contrast, the Gal-GalNAc lectin exclusively triggers invasion of the liver. These observations are in agreement with emerging studies that highlight marked differences in the way that cells migrate in vitro in two dimensions versus in vivo in three dimensions. The approach that we have developed should be powerful to identify adhesive complexes required for in vivo cell migration in normal and pathogenic situations and may, thereby, lead to new therapeutic drug, for pathologies based on cell motility and adhesion.

Dynamic instability of the intracellular pressure drives bleb-based motility

“…In vitro, these protrusions can either retract or become stable and thus sustain the exploration of the local environment by the cell over several hours (Coudrier et al, 2005). In the absence of externally guided cell motility, there is no correlation between the directions of the protrusions, and efficient, random exploration of the substrate is observed.…”

“…In previous work using in vivo two-photon imaging, we observed that Eh migration in the liver during the infectious process is accompanied by very intense, cyclic production of spherical protrusions of the plasma membrane (Coudrier et al, 2005). In vitro, these protrusions can either retract or become stable and thus sustain the exploration of the local environment by the cell over several hours (Coudrier et al, 2005).…”

Obtención de anticuerpos monoclonales de ratón contra proteasa de cisteína 5 recombinante de Entamoeba histolytica

“…La ausencia de la EhCP5 en E. dispar, se considera de gran relevancia, pues se cree que es una de las principales causas para que esta especie no sea patógena (10)(11)(12)(13)(14).…”

The domain structure of Entamoeba α-actinin2

“…The completion of the E. histolytica genome and its subsequent analysis have been crucial in revealing the key elements involved in the cytoskeleton dynamic and identifying the proteins involved in infection [16,17]. Adhesion to the host cell requires a galactose/N-acetylgalactosamine inhibitable lectin (Gal/GalNAc lectin) [18] and cysteine proteases [19,20] in addition to actin-binding proteins and a reorganization of the cytoskeleton [12,[21][22][23]. Analyses of potential interacting partners of the Gal/GalNAc lectin showed that two proteins rich in glutamic acid and lysine [24] and an α-actinin-like protein are attached to the lectin [9].…”

“…Motility and phagocytosis are implicated in the virulence of the parasite, and are crucial for its pathogenesis [7,8]. As both processes are driven by dynamic fluctuations of the cytoskeleton, much interest has been focused on the characterization of the Entamoeba histolytica actin-binding proteins [9][10][11] and the proteins involved in cytoskeletal reorganization [12][13][14][15]. The completion of the E. histolytica genome and its subsequent analysis have been crucial in revealing the key elements involved in the cytoskeleton dynamic and identifying the proteins involved in infection [16,17].…”