Comparative characterization of microRNAs in Schistosoma japonicum schistosomula from Wistar rats and BALB/c mice

Abstract

More than 40 kinds of mammals in China are known to be naturally infected with Schistosoma japonicum (S. japonicum) (Peng et al. Parasitol Res 106:967-76, 2010). Compared with permissive BALB/c mice, rats are less susceptible to S. japonicum infection and are considered to provide an unsuitable microenvironment for parasite growth and development. MicroRNAs (miRNAs), via the regulation of gene expression at the transcriptional and post-transcriptional levels, may be responsible for developmental differences between schistosomula in these two rodent hosts. Solexa deep-sequencing technology was used to identify differentially expressed miRNAs from schistosomula isolated from Wistar rats and BALB/c mice 10 days post-infection. The deep-sequencing analysis revealed that nearly 40 % of raw reads (10.37 and 10.84 million reads in schistosomula isolated from Wistar rats and BALB/c mice, respectively) can be mapped to selected mirs in miRBase or in species-specific genomes. Further analysis revealed that several miRNAs were differentially expressed in schistosomula isolated from these two rodents; 18 were downregulated (by <2-fold) and 23 were up-regulated (>2-fold) (expression levels in rats compare with those in mice). Additionally, three novel miRNAs were primarily predicted and identified. Among the 41 differentially expressed miRNAs, 4 miRNAs had been identified with specific functions in schistosome development or host-parasite interaction, such as sexual maturation (sja-miR-1, sja-miR-7-5p), embryo development (sja-miR-36-3p) in schistosome, and pathogenesis of schistosomiasis (sja-bantam). Then, the target genes were mapped, filtered, and correlated with a set of genes that were differentially expressed genes in schistosomula isolated from mice and rats, which we identified in a S. japonicum oligonucleotide microarray analysis in a previous study. Gene Ontology (GO) analysis of the predicted target genes of 13 differentially expressed miRNAs revealed that they were involved in some important biological pathways, such as metabolic processes, the regulation of protein catabolic processes, catalytic activity, oxidoreductase activity, and hydrolase activity. The study presented here includes the first identification of differentially expressed miRNAs between schistosomula in mice or rats. Therefore, we hypothesized that the differentially expressed miRNAs may affect the development, growth, and maturation of the schistosome in its life cycle. Our analysis suggested that some differentially expressed miRNAs may impact the survival and development of the parasite within a host. This study increases our understanding of schistosome development and host-parasite interactions.

A MicroRNA Derived From Schistosoma japonicum Promotes Schistosomiasis Hepatic Fibrosis by Targeting Host Secreted Frizzled-Related Protein 1

“…Sja-miR-1 was abundant in Schistosoma japonicum and considered playing an important role in schistosome sexual maturation (Cai et al, 2013;Han et al, 2015). This study provides the following evidence that the sja-miR-1 is involved in the occurrence and progression of hepatic fibrosis during schistosome infection: (1) sja-miR-1 was present in HSCs and involved in host HSC activation by targeting the Sfrp1;…”

Changes in microRNA expression in response to Schistosoma japonicum infection

“…Previous studies have shown that the sequences of some schistosomal miRNAs are conserved; they are homologous with those of other species including mice, rats and other hosts and may carry out similar biological functions . In addition, a study by Hu et al.…”

“…miRNAs also modulate the response to pathogens by affecting the inflammatory response, autoimmune disorders and metabolic disorders . Recently, an increasing number of schistosome miRNAs have been identified with conventional cloning methods and the deep‐sequencing technique in S. japonicum and S. mansoni, in different developmental stages including cercariae, schistosomula, adult worms and eggs . Differential expression of certain miRNAs has been observed between schistosomes from different developmental stages, or between male and female worms, as well as between hosts with different susceptibility to schistosome infection.…”

“…Differential expression of certain miRNAs has been observed between schistosomes from different developmental stages, or between male and female worms, as well as between hosts with different susceptibility to schistosome infection. This suggests that miRNAs play a distinct role in modulating the metabolism, differentiation, development, maturation and reproduction of the parasite . Several papers have shown that the immune response and temporal gene transcriptional profiles are changed in hosts following schistosome infection, during different infection periods or in different schistosome‐susceptible hosts .…”

Epigenetics in Schistosomes: What We Know and What We Need Know

“…Compared with permissive BALB/c mice, rats are less susceptible to S. japonicum infection and are considered to provide an unsuitable microenvironment for parasite growth and development. Forty-one differentially expressed miRNAs have been identified in comparisons of rats and mice (Han et al, 2015). One hundred sixty-two miRNAs are expressed in M. fortis in mice, with 12 in the liver, 32 in the spleen and 34 in the lung being differentially expressed in M. fortis (Han et al, 2013).…”