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Background: Schistosomiasis japonica remains a significant public health problem in China and Southeast Asian countries. The most typical and serious outcome of the chronic oriental schistosomiasis is the progressive granuloma and fibrosis in the host liver, which has been a major medical challenge. However, the molecular mechanism underling the hepatic pathogenesis is still not clear. Methodology and Principal Findings: Using microarrays, we quantified the temporal gene expression profiles in the liver of Schistosoma japonicum-infected BALB/c mice at 15, 30, and 45 day post infection (dpi) with that from uninfected mice as controls. Gene expression alternation associated with liver damage was observed in the initial phase of infection (dpi 15), which became more magnificent with the onset of egg-laying. Up-regulated genes were dominantly associated with inflammatory infiltration, whereas down-regulated genes primarily led to the hepatic functional disorders. Simultaneously, microRNA profiles from the same samples were decoded by Solexa sequencing. More than 130 miRNAs were differentially expressed in murine liver during S. japonicum infection. MiRNAs significantly dysregulated in the mid-phase of infection (dpi 30), such as mmu-miR-146b and mmu-miR-155, may relate to the regulation of hepatic inflammatory responses, whereas miRNAs exhibiting a peak expression in the late phase of infection (dpi 45), such as mmu-miR-223, mmu-miR-146a/b, mmu-miR-155, mmu-miR-34c, mmu-miR-199, and mmu-miR-134, may represent a molecular signature of the development of schistosomal hepatopathy. Further, a dynamic miRNA-gene co-expression network in the progression of infection was constructed. Conclusions and Significance: This study presents a global view of dynamic expression of both mRNA and miRNA transcripts in murine liver during S. japonicum infection, and highlights that miRNAs may play a variety of regulatory roles in balancing the immune responses during the development of hepatic pathology. The data provide robust information for further researches on the pathogenesis and molecular events of hepatopathy induced by schistosome eggs. [ABSTRACT FROM AUTHOR]

Background: Schistosoma japonicum is a parasitic flatworm that causes zoonotic schistosomiasis. The typical outcome of schistosomiasis is hepatic granuloma and fibrosis, which is primarily induced by soluble egg-derived antigens. Although schistosomal eggs represent an important pathogenic stage to the host, the biology of this critical stage is largely unknown. We previously investigated the expression profiles of sncRNAs during different developmental stages of this parasite. However, using small RNA extracted from egg-deposited liver tissues generated limited information about sncRNAs in eggs. Here, we characterized the complete small RNAome in this stage of the parasite after optimization of RNA purification. Methodology and Principal Findings: A library, SjE, was constructed with the small RNA extracted from S. japonicum eggs and subjected to high-throughput sequencing. The data were depicted by comprehensive bioinformatic analysis to explore the expression features of sncRNAs in the egg stage. MicroRNAs accounted for about one quarter of the total small RNA population in this stage, with a strongly biased expression pattern of certain miRNA family members. Sja-miR-71, sja-miR-71-5p, and sja-miR-36-3p were suggested to play important roles in embryo development. A panel of transfer RNA fragments (tRFs) precisely processed from the 5′ end of mature tRNAs was identified for the first time, which represented a strong egg stage-biased expression. The tRNA-Ala derived small RNAs were the most highly expressed Sj-tRFs in eggs. Further, the expression of siRNAs from 29 types of well-defined transposable elements (TEs) was observed to be relatively stable among different developmental stages. Conclusions and Significance: In this study, we characterized the sncRNA profile in the egg stage of S. japonicum. Featured expression of sncRNAs, especially the tRNA-derived small RNAs, was identified, which was further compared with that of other developmental stages. These novel findings would facilitate a deeper understanding of the biology of schistosomal parasites. [ABSTRACT FROM AUTHOR]