Prolyl Oligopeptidase from the Blood Fluke Schistosoma mansoni: From Functional Analysis to Anti-schistosomal Inhibitors

Abstract

BackgroundBlood flukes of the genus Schistosoma cause schistosomiasis, a parasitic disease that infects over 240 million people worldwide, and for which there is a need to identify new targets for chemotherapeutic interventions. Our research is focused on Schistosoma mansoni prolyl oligopeptidase (SmPOP) from the serine peptidase family S9, which has not been investigated in detail in trematodes.Methodology/Principal FindingsWe demonstrate that SmPOP is expressed in adult worms and schistosomula in an enzymatically active form. By immunofluorescence microscopy, SmPOP is localized in the tegument and parenchyma of both developmental stages. Recombinant SmPOP was produced in Escherichia coli and its active site specificity investigated using synthetic substrate and inhibitor libraries, and by homology modeling. SmPOP is a true oligopeptidase that hydrolyzes peptide (but not protein) substrates with a strict specificity for Pro at P1. The inhibition profile is analogous to those for mammalian POPs. Both the recombinant enzyme and live worms cleave host vasoregulatory, proline-containing hormones such as angiotensin I and bradykinin. Finally, we designed nanomolar inhibitors of SmPOP that induce deleterious phenotypes in cultured schistosomes.Conclusions/SignificanceWe provide the first localization and functional analysis of SmPOP together with chemical tools for measuring its activity. We briefly discuss the notion that SmPOP, operating at the host-parasite interface to cleave host bioactive peptides, may contribute to the survival of the parasite. If substantiated, SmPOP could be a new target for the development of anti-schistosomal drugs.

Next Generation Sequencing Identifies Five Major Classes of Potentially Therapeutic Enzymes Secreted byLucilia sericataMedical Maggots

“…Interestingly, a prolyl oligopeptidase was recently identified in the human parasite Schistosoma mansoni . Although the enzyme is not secreted by the parasite, it cleaves the human vasoregulatory peptides bradykinin and angiotensin I in vitro , thus potentially modulating or dysregulating homeostasis in its host [ 189 ]. We identified 9 clusters and 4 peptidase species representing L. sericata prolyl oligopeptidases.…”

Prolyl oligopeptidase-like deficient Trypanosoma evansi parasites are associated with reduced interleukin-10 concentrations in vivo and in vitro

“…Although POPs from different species share similar three-dimensional structures, divergences have been observed between species in terms of inhibition and the specificity of substrates that they hydrolyse (Kaszuba et al 2012;Bastos et al 2013). Whereas recombinant POPs from T. brucei and T. cruzi are capable of hydrolysing proline rich native collagen, recombinant POP from Schistosoma mansoni is unable to hydrolyse substrates such as human collagens type I and IV (Bastos et al 2005(Bastos et al , 2010Fajtová et al 2015). The exact physiological functions of POPs are yet to be fully understood, with functions seemingly related to the infective species.…”

“…Parasites that die as a result of the host immune response release biologically active products that have been associated with disease symptoms (Taylor and Authié, 2004;Antoine-Moussiaux et al 2009). These toxins include enzymes such as trypanosome peptidases that hydrolyse host proteins, trypanosome phospholipases that hydrolyse red blood cell membranes and trypanosome trans-sialidases that act as important factors for virulence and anaemia (Tizard et al 1978;Antoine-Moussiaux et al 2009;Coustou et al 2012;Habila et al 2012). The study of these factors, and in particular peptidases, led to the idea of developing new anti-disease vaccines that target trypanosome products that are associated with disease symptoms (Authié, 1994;Authié et al 2001;Antoine-Moussiaux et al 2009).…”

Laser capture microdissection in combination with mass spectrometry: Approach to characterization of tissue-specific proteomes ofEudiplozoon nipponicum(Monogenea, Polyopisthocotylea)

“…After fixation, samples were rinsed with PBS buffer and transferred into cryofixation molds, which were then immersed in OCT compound (Tissue-Tek ® ) and left for 1 hr in room temperature. The molds were then placed in dry ice and frozen blocks stored at −80°C ([45], modified).…”