Innovation Groups of Animal Schistosomiasis, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
Schistosomiasis caused by trematode flatworms of the genus Schistosoma currently afflicts ∼200 million people in 76 countries worldwide. Currently, no successful vaccine is available for schistosomiasis. Praziquantel (PZQ) is now virtually the only drug being used for treating the disease. However, due to its large administration and its ineffectiveness for juvenile parasites, serious concerns about the future development of tolerance or resistance of schistosomes to PZQ have already been raised. Schistosomes have an unusual biological feature, distinct sexual dimorphism between male and female worms. Male−female pairing is a prerequisite for female development, sexual maturation, and subsequent egg production. A large number of eggs produced from adult females are primarily responsible for the pathogenesis of schistosomiasis as well as disease dissemination. Consequently, deeply understanding the molecular basis of these processes regarding schistosome development and sexual maturation may result in the identification of novel drug targets and vaccines to retard parasite development, to block egg production, and then to lessen the pathogenesis and disease dissemination. Protein phosphorylation is an important posttranslational modification in many organisms that regulates numerous cellular processes. However, it remains poorly characterized in schistosomes, the causative agent of schistosomiasis in humans and related animals. In the present study, we determined differentially expressed proteins and phosphoproteins between adult females (35 days) and adult males (35 days) in S. japonicum. A total of 1758 phosphopeptides and 2104 proteins were quantitatively determined. Bioinformatic analyses revealed that several proteins may play an important role in the regulation of schistosome development by directly or indirectly interacting with other co-detected signal molecules. Additionally, some differentially expressed proteins between male and female schistosomes were further validated either by immunohistochemistry or by real-time reverse transcription polymerase chain reaction (RT-PCR) at transcript levels. In summary, these findings as well as the providing of an inventory of phosphoproteins are expected to provide new insights into schistosome development and sexual maturation and then may result in the development of novel interventions against schistosomiasis.