Comparative Analysis Of Transcriptome And Proteome Of Schistosoma Japonicum Adult Worms Derived From Primary Infected And Re-Infected Water Buffaloes

Schistosoma japonicum(S.japonicum)is an important zoonotic parasite.Water buffalo is an important reservoir of S.japonicum and an important source of transmission for schistosomiasis.It has been proved that water buffalo has the ability of self-curing after infection of S.japonicum.In our previous study,we have observed that the re-infected water buffalo has 97% reduction in worm burden and a shorter female worm length.In order to study the host-parasite relationship of S.japonicum in water buffaloes,we observed the phenotypic differences of worms from primary and reinfected buffaloes,detected the evolution of ILs mRNA expression level in peripheral blood lymphocyte of water buffaloes in both groups,and illustrated the differently expressed genes in mRNA level and the differently expressed proteins between the worms from primary and reinfected buffaloes by RNA-Seq transcriptome sequencing and TMT-based proteomics techniques.1.Morphological observation of worms and mRNA expression analysis in peripheral blood lymphocyte of water buffaloesThe length of the worm and the size of each organ of worms from water buffaloes in two groups were determined.Compared with the worms in the primary infection of water buffalo,the organs of males and females from re-infected water buffalo were significantly smaller(P < 0.05).In addition,the number of eggs in the uterus of females from re-infected water buffalo was also significantly reduced(P < 0.05).Analysis of cytokine expression in peripheral blood lymphocytes of water buffaloes showed that the IFN-γ expression level in re-infected animals was significantly increased before challenge infection and this might related to the anti re-infection of water buffaloes.These results indicate that buffaloes previously infected with schistosome may not only kill most of worms in re-infection but also affect the growth and development of the survived worms.2.Comparative analysis of transcriptional profiles of wormsWe compared the differences in transcriptional expression of adult S.japonicum worms recovered from primary infected and re-infected water buffaloes using Illumina RNA-sequencing(RNA-Seq)technology.A total of 13,605 genes were identified,112 were differentially expressed,including 51 up-regulated and 61 down-regulated genes,in worms from re-infected compared with primary infected water buffaloes.Gene ontology(GO)enrichment analysis revealed that GO terms such as “oxidation-reduction process,” “calcium-dependent phospholipid binding,” “lipid binding” and “calcium ion binding” were significantly enriched in down regulated genes,whereas GO terms related to metabolism and biosynthesis were significantly enriched in up-regulated genes.The results revealed that the down-regulation of some important genes might contribute to reduction in worm numbers and maldevelopment of surviving worms in re-infected water buffaloes.Furthermore,up-regulation of genes related to metabolic processes and biosynthesis might be a compensatory mechanism of worms to disadvantageous environments.3.Comparative proteomic analysis of S.japonicum adult wormsWe identified 14 significantly differentially expressed proteins(DEPs)by performing TMT-based proteomics techniques.GO pathway analysis found that DEPs are mainly involved in the redox reaction process,TOR signaling pathway and protein metabolism process.Specifically,the up-regulated proteins mainly affect the wound-healing of the worm,repair of epidermal damage and function,and the down-regulated proteins is mainly related to the cellular iron metabolism,growth,cell proliferation and differentiation and immune escape,protein degradation,translation process of genetic material,DNA-damage responses and regulation of immune synapses.In KEGG enrichment analysis,we found that these DEPs are mainly involved in the AGE-RAGE signaling pathway.Conclusion: In this study,we defined the morphological,transcriptomic and proteomic differences in S.japonicum from primary infected and re-infected water buffaloes,and initially clarified the causes of injury from reinfected buffalo worms.The biological mechanism of anti-reinfection provides useful information and lays the foundation for the development of new anti-schistosomiasis drugs and vaccines.