Effects of programmed cell death protein 10 on the Schistosoma japonicum female reproductive system

•Granulomas induced by egg-laying are a major pathological symptom of schistosomiasis.•Schistosoma japonicum reproduction could be a schistosomiasis treatment target.•Programmed cell death protein 10 (PCDP10) is important for S. japonicum reproduction.•PCDP10 knockdown adversely affected reproductive organ structure and function.•PCDP10 thus may be a potential target for controlling schistosomiasis oviposition. This study aimed to investigate the effects of programmed cell death protein 10 (PCDP10) on the female reproductive system of Schistosoma japonicum, one of the major infectious agents of schistosomiasis. We found that PCDP10 was widely distributed in the integument, the worm parenchymal area, and the vitellarium of the female worm, but was localized to a lesser extent in the ovary and testicles. RNAi experiments successfully achieved gene knockdown, and the ultrastructural morphology of the adult reproductive organs was observed. The results demonstrated that, compared with those of the negative control group, the number of cortical granules around oocytes decreased and the number of immature oocyte cells increased. Fusion of yolk globules occurred, and the number and the diameter of yolk droplets decreased significantly. Real-time PCR showed that the expression of yolk glands reached its peak before ovulation and then decreased. The TUNEL assay results showed that apoptosis in the RNAi group was significantly higher than that in the negative control group. These results suggested that SjPCDP10 plays an important role in the female reproductive system. In conclusion, PCD10 is involved in oocyte growth and development, especially in eggshell formation, which may provide a reference for further elucidating the molecular mechanism of PCDP10 involved in egg formation and embryo development in Schistosoma japonicum.