Cloning, expression, and characterization of Schistosoma japonicum tegument protein phosphodiesterase-5

Abstract

The tegument proteins of schistosomes are regarded as potential vaccine candidates and drug targets to control schistosomiasis. Nucleotide pyrophosphatase/phosphodiesterase-5 (NPP-5), which belongs to a multigene family of nucleotide pyrophosphatase/phosphodiesterases (NPPs), is important in the hydrolysis of pyrophosphate or phosphodiester bonds in nucleotides and their derivatives. In the present study, SjNPP-5, identified as one of the tegument proteins of Schistosoma japonicum in our previous proteomic studies, was cloned on a fragment of 1,371 bp and expressed as a recombinant protein of 69 kDa. Real-time RT-PCR analysis showed that SjNPP-5 was up-regulated at 21-42 days, and the expression level in 42-day-old male worms was almost nine times higher than that in females. Western blot analysis revealed that rSjNPP-5 had good antigenicity. Immunofluorescence analysis found that SjNPP-5 was a membrane-associated antigen mainly distributed on the surface of the male adult worm of S. japonicum. BALB/c mice vaccinated with rSjNPP-5 three times showed a 29.90% worm reduction (P < 0.05) and a 26.21% egg count reduction (P > 0.05). Immunization with rSjNPP-5 induced a mixed Th1/Th2 response in which Th1 was dominant. The response was characterized by a reduced IgG1/IgG2a ratio and elevated production of cytokines IFN-γ and IL-4. This study suggested that SjNPP-5 may be important in schistosome development, and further investigations are required to fully understand the function of this molecule.

Molecular cloning and characterization of a cyclophilin A homologue from Schistosoma japonicum

“…Human schistosomiasis is one of the most prevalent and serious parasitic diseases worldwide, with an estimated 200 million people currently diagnosed with the disease in tropical and subtropical regions (Wang et al 2009;Zhang et al 2012). Schistosomiasis is mainly caused by Schistosoma species japonicum, mansoni, and haematobium.…”

Immunization with tegument nucleotidases associated with a subcurative praziquantel treatment reduces worm burden followingSchistosoma mansonichallenge

“…On the other hand, the T-cell immune response that was induced was counter-balanced by a strong regulatory response, characterized by TGF-β. Moreover, it has been demonstrated that immunization with NPP-5 from S. japonicum, resulted in a partial worm burden reduction following a subsequent challenge (Zhang et al, 2012a). Therefore it is possible that a properly folded protein would show a different result.…”

A key tyrosine substitution restricts nucleotide hydrolysis by the ectoenzyme NPP5

“…The vampire snail Colubraria reticulata secretes anticoagulants during feeding, and a protein similar to NPP5 is highly expressed in its salivary tissue [19]. In the parasitic flatworms Schistosoma mansoni and Schistosoma japonicum, which live in blood capillaries, an ortholog of NPP5 is also present, on the outer layer of the worm [20,21]. Interestingly, SmNPP5 can hydrolyze p-nitrophenyl-TMP [20,22] and was proposed to participate in catabolism of extracellular nucleotides [27].…”

“…In contrast, it was identified as an angiogenesisrelated gene in pediatric high-grade glioma [18]. Orthologs of this enzyme have been reported in the salivary tissue of the vampire snail which feeds on the blood of fish [19] and in parasitic flatworms that live in blood capillaries [20][21][22]. Metabolism of nucleotides in the circulation was proposed as a function for these homologs.…”