ABSTRACT: Background: In immunodeficient mice, the growth and egg laying of schistosome were significantly retarded or inhibited, and their virulence on the host was also weakened. Some studies have suggested that host factors including endocrine and immune signals can modulate the parasite’s development and maturation. However, it is still not clear for the molecular mechanisms underlying the growth and maturation regulation of schistosome. Methodology/Principal results: We isolated the total RNAs of female and male schistosome from immunodeficient SCID mice and immunocompetent BALB/c mice (labeled as S_F, S_M, B_F and B_M) obtained at five weeks post infection with cercariae, and constructed cDNA libraries for RNA deep sequencing on an Illumina (Solexa) platform. In the results, the mRNAs were distinguished from long non-coding RNAs after blast to the reference Schistosoma japonicum genome, assemble and assessment of coding potential of the clean reads between S_F and B_F, and between S_M and B_M. The RNA-Seq yielded 90 to 142 million raw reads and 84 to 134 million clear reads per sample for the four schistosome samples. There are 56% to 65% of the clean reads mapped to the reference S. japonicum genome data. Given P-value <0.05, 298 differentially expressed genes (DEGs, mRNAs) for pairwise comparison of the above schistosome samples were identified. In detailed, 240 DEGs were identified in S_F vs B_F, of which 152 DEGs were up-regulated (147 DEGs were present in S_F worms but absent or undetected technically in B_F worms) and 88 were down-regulated (83 DEGs were present in B_F worms but absent or undetected technically in S_F worms). 62 DEGs were identified in S_M vs B_M, of which 39 were up-regulated (29 DEGs were present in S_M worms but absent or undetected technically in B_M worms) and 23 were down-regulated (22 DEGs were present in B_M worms but absent or undetected technically in S_M worms). Four differentially expressed mRNAs were shared among the two comparisons (present both in female and male worms), which were Sjp_0117620 (26S proteasome subunit P28-related), Sjp_0127870 (leucine zipper-EF-hand-containing transmembrane protein 1, mitochondrial precursor), Sjp_0130040 (putative dynein heavy chain) and Sjp_0094540 (hypothetical protein containing proteinase inhibitor I25, cystatin domain，SJCHGC07500 protein, partial). There were other 236 DEG specific in the comparison of S_F and B_F, and 58 DEG specific in the comparison of S_M and B_M. GO analysis was performed to summarize and explore the major GO categories of the DEGs which may be susceptible to host environments. The above DEGs of female comparison and male comparison were annotated with GO terms in three independent categories: biological processes (400 GO terms were hit for annotation of DEGs of female comparison and 287 GO terms were hit for annotation of DEGs of male comparison), molecular functions (231 GO terms were hit for annotation of DEGs of female comparison and 163 GO terms were hit for annotation of DEGs of male comparison), and cellular components (88 GO terms were hit for annotation of DEGs of female comparison and 75 GO terms were hit for annotation of DEGs of male comparison). The biological processes analysis revealed the predominant DEGs of female worms were involved in response to microtubule-based process, while predominant DEGs of male worms were involved in response to response to DNA damage stimulus, oxidation-reduction process and cellular response to stress. The molecular functions, some DEGs of female and male worms were annotated with calcium-dependent phospholipid binding activities in common. Notably, genes coding for microtubule associated complex, cytoskeletal part, cytoskeleton and microtubule cytoskeleton accounted for large portion of annotated DEGs of female worms in the cellular components analysis, while gene coding for nucleoplasmic THO complex of male worms were identified in the cellular components analysis. The KEGG pathway analysis showed many of the DEGs of female worms were involved in purine metabolism, RNA polymerase, fatty acid biosynthesis, fatty acid degradation and pyrimidine metabolism. Many of the DEGs of male worms were involved in oxidative phosphorylation, riboflavin metabolism and tyrosine metabolism. Conclusions/Significance: This study provides a comparative gene expression profiles of schistosomes derived from SCID mice and immunocompetent BALB/c mice. A number of genes potentially regulating the development of schistosomes were identified. These findings lay the foundation for schistosomiasis research in parasite-host interaction at the transcriptional level and provide a valuable resource for screening antischistosomal intervention targets or vaccine candidates.
