A hydrophobic ligand‐binding protein of the Taenia solium metacestode mediates uptake of the host lipid: Implication for the maintenance of parasitic cellular homeostasis

Abstract

Parasitic organisms are incapable of de novo fatty acid synthesis due to a down-regulated expression of enzymes involved in the oxygen-dependent pathway. We investigated the uptake of host lipids by a 150-kDa hydrophobic ligand-binding protein (HLBP) of Taenia solium metacestode, an agent causative of neurocysticercosis. The protein was found to be a hetero-oligomeric complex consisting of multiple subunits (M(r) 7, 10, and 15 kDa within pH 8.0-9.7), which may originate from four unique genes of 7- and 10-kDa gene families with 2-3 polymorphic alleles/paralogs. The 15-kDa protein represented glycosylated forms of the 10-kDa. With high binding affinity to lipid analogs, these subunits evidenced high-level sequence identity with other cestode HLBPs and form a novel clade associated with excretory-secretory type HLBP. In vitro experiments with viable worms suggested that the excreted 150-kDa protein might bind to lipids, and participate in the translocation of host lipids across the syncytial membrane. This process was substantially inhibited by the specific anti-150 kDa antibodies. The protein was localized in the parasite syncytium and in the lipid droplets within host granuloma wall, where significant lipase activity was expressed. HLBP-mediated uptake of the host lipid may be critical for the parasite survival and thus could be targeted by chemotherapeutics and/or vaccine.

Cloning, characterization, and expression of a novel secretory lipase-like gene from Clonorchis sinensis

“…In Legionella pneumophila, lipolytic enzyme activities were considered to contribute to the destruction of the alveolar lining during infection (Galka et al 2008). Significant lipase activity is expressed in Taenia solium metacestode syncytium and in the lipid droplets within host granuloma wall; the uptake of the host lipid is considered critical for parasite survival (Lee et al 2007a). A phospholipase present on the surface of Plasmodium berghei sporozoites had been verified for its lipase and membrane lytic activity, as well as its involvement in the establishment of a malaria infection (Bhanot et al 2005).…”

Spatiotemporal Expression Patterns and Antibody Reactivity of Taeniidae Endophilin B1

“…(several antigen B isoforms) (19,20,37,38), except for a few entities in the case of AE (37). Those proteins are rapidly drained and absorbed with parasite involution and result in minimal antibody responses in chronic cases (19,20,23,39,40). In contrast, parenchymal cellular components, such as the scolex/protoscolex and the bladder wall/germinal layer, may be relatively resistant to degenerative changes.…”

Characterisation of Antigen B Protein Species Present in the Hydatid Cyst Fluid of Echinococcus canadensis G7 Genotype

“…This has led to emphasise its hypothetical role in parasite lipid metabolism, taking up host lipids as building blocks for parasite metabolic demands. Moreover, this hypothesis is supported by the fact that AgB belongs to a cestode-specific family of proteins exhibiting ability to bind hydrophobic ligands (HLBP for hydrophobic ligand binding protein) [15,16]. This family has emerged by independent gene expansion events, giving rise to species and gene-specific monophyletic clades.…”