Schistosomes and snails: a molecular encounter

Abstract

Biomphalaria glabrata snails play an integral role in the transmission of Schistosoma mansoni, the causative agent for human schistosomiasis in the Western hemisphere. For the past two decades, tremendous advances have been made in research aimed at elucidating the molecular basis of the snail/parasite interaction. The growing concern that there is no vaccine to prevent schistosomiasis and only one effective drug in existence provides the impetus to develop new control strategies based on eliminating schistosomes at the snail-stage of the life cycle. To elucidate why a given snail is not always compatible to each and every schistosome it encounters, B. glabrata that are either resistant or susceptible to a given strain of S. mansoni have been employed to track molecular mechanisms governing the snail/schistosome relationship. With such snails, genetic markers for resistance and susceptibility were identified. Additionally, differential gene expression studies have led to the identification of genes that underlie these phenotypes. Lately, the role of schistosomes in mediating non-random relocation of gene loci has been identified for the first time, making B. glabrata a model organism where chromatin regulation by changes in nuclear architecture, known as spatial epigenetics, orchestrated by a major human parasite can now be investigated. This review will highlight the progress that has been made in using molecular approaches to describe snail/schistosome compatibility issues. Uncovering the signaling networks triggered by schistosomes that provide the impulse to turn genes on and off in the snail host, thereby controlling the outcome of infection, could also yield new insights into anti-parasite mechanism(s) that operate in the human host as well.

Pathogen-associated molecular patterns activate expression of genes involved in cell proliferation, immunity and detoxification in the amebocyte-producing organ of the snail Biomphalaria glabrata

“…Recent molecular studies have focused on snail immunity, with an aim to better understand the mechanism of snail defense against schistosome parasites (Adema and Loker, 2015; Knight et al, 2014; Lockyer et al, 2012; Tennessen et al, 2015). …”

Cytometric analysis, genetic manipulation and antibiotic selection of the snail embryonic cell line Bge from Biomphalaria glabrata, the intermediate host of Schistosoma mansoni

“…As the only known established molluscan cell line, the Biomphalaria glabrata embryonic cell line, Bge, represents a noteworthy resource for in vitro studies on the cellular and molecular basis of the relationship between the parasitic trematode, Schistosoma mansoni , etiological agent of the neglected tropical disease schistosomiasis, and its snail host (Knight et al, 2014). Recently there has been a rapid increase in “omics” based projects for both the parasite and snail that generated genomic and transcriptomic profiles (Raghavan and Knight, 2006; Berriman et al, 2009; Brindley et al, 2009; Chuan et al, 2010; Protasio et al, 2012; Zerlotini et al, 2013).…”

“…Recently there has been a rapid increase in “omics” based projects for both the parasite and snail that generated genomic and transcriptomic profiles (Raghavan and Knight, 2006; Berriman et al, 2009; Brindley et al, 2009; Chuan et al, 2010; Protasio et al, 2012; Zerlotini et al, 2013). In order to take advantage of the in vitro culture of the blood fluke intra-snail developmental stages, we considered that it was desirable to not only define cell characteristics of Bge cells, but also optimize functional genomic approaches to investigate the parasitism of the intermediate host by the parasite (Knight et al, 2014). …”

The Susceptibility of <i>Biomphalaria</i> spp. from Mwea Irrigation Scheme in Kenya against <i>Schistosoma mansoni</i> Miracidia Infection

“…With the current interest in eliminating schistosomiasis, various snails control strategies need to be devised. Breaking the life cycle of the parasites will offer an option to decrease transmission, by targeting intermediate host snails [15,16]. The use of genetically resistant snail vector to displace susceptible populations has been suggested [17,18].…”