Activity profiling of peptidases in Angiostrongylus costaricensis first-stage larvae and adult worms

Abstract

BackgroundAngiostrongylus costaricensis is a relatively uncharacterized nematode that causes abdominal angiostrongyliasis in Latin America, a human parasitic disease. Currently, no effective pharmacological treatment for angiostrongyliasis exists. Peptidases are known to be druggable targets for a variety of diseases and are essential for several biological processes in parasites. Therefore, this study aimed to systematically characterize the peptidase activity of A. costaricensis in different developmental stages of this parasitic nematode.Methodology/Principal findingsA library of diverse tetradecapeptides was incubated with cellular lysates from adult worms and from first-stage larvae (L1) and cleaved peptide products were identified by mass spectrometry. Lysates were also treated with class specific peptidase inhibitors to determine which enzyme class was responsible for the proteolytic activity. Peptidase activity from the four major mechanistic classes (aspartic, metallo, serine and cysteine) were detected in adult worm lysate, whereas aspartic, metallo and serine-peptidases were found in the larval lysates. In addition, the substrate specificity profile was found to vary at different pH values.Conclusions/SignificanceThe proteolytic activities in adult worm and L1 lysates were characterized using a highly diversified library of peptide substrates and the activity was validated using a selection of fluorescent substrates. Taken together, peptidase signatures for different developmental stages of this parasite has improved our understanding of the disease pathogenesis and may be useful as potential drug targets or vaccine candidates.

Abdominal angiostrongyliasis in the Americas: fifty years since the discovery of a new metastrongylid species, Angiostrongylus costaricensis

“…Other studies have assessed possible functions and applications of the identified proteins by using protein activity assays [ 77 , 93 ] and cloning parasite sequences into plasmids [ 94 ]. A synthetic peptide of the serine/threonine phosphatase 2A (PP2A), an enzyme involved in the embryogenesis and differentiation of A. costaricensis , was tested as a vaccine candidate in murine hosts [ 94 ].…”

“…This synthetic peptide conferred 60 to 100% protection against A. costaricensis challenge, with a significant increase in IFN-γ and IL-17 levels [ 94 ]. In addition, the proteolytic activity of this worm’s peptides was investigated and showed significant differences among the proteins derived from adult worms and L1 and L3 larvae [ 93 ]. These findings revealed important factors of the complex infection process and promoted different views of potential alternative methods of disease treatment and interruption of life-cycle transmission.…”

A comparative ‘omics’ approach for prediction of candidate Strongyloides stercoralis diagnostic coproantigens

“…Very few aspartic peptidases were DE, but had high expression in parasitic females and homologues to S. ratti E/S proteins. Aspartic peptidases play a role in haemoglobin digestion in other parasitic helminths, therefore secretion may be linked to feeding within the host gut epithelium where the adult worm resides [74, 75]. We identified a single candidate antigen from the few examined aspartic peptidases which had considerable homology to aspartic proteases from other Strongyloides species, but little to any other relevant species, whereas the full protein had high homology to multiple relevant nematode species including hookworm.…”

A comparative ‘omics’ approach for prediction of candidate Strongyloides stercoralis diagnostic coproantigens

“…Very few aspartic peptidases were DE, but had high expression in parasitic females and homologues to S. ratti E/S proteins. Aspartic peptidases play numerous roles in parasitic helminths including digestion, immune evasion and tissue invasion, among others linked to feeding within the host gut epithelium where the adult worm resides [81]. We identified a single candidate antigen from the few examined aspartic peptidases which had considerable homology to aspartic proteases from other Strongyloides species, but little to any other relevant species, whereas the full protein had high homology to multiple relevant nematode species including hookworm.…”