Seroprevalence Of Yak Infection With Fasciola Hepatica In Gansu Province And Analysis Of MRNA Transcriptome And Mi Rnome Of Different Development Stages Of Fasciola Gigantica

Fasciola hepatica and F.gigantica are the major causative agents of fascioliasis,an economically important disease in livestock.F.hepatica infection usually occurs in temperate zones,and F.gigantica occurs in tropical and subtropical areas.It is estimated that up to 2.4 million humans are infected and about 180 million are at risk worldwide.In China,F.hepatica infection have been widely reported,however,information about prevalence of Fasciola in yaks(Bos grunniens)is limited.Furthermore,F.gigantica is regarded as the major liver fluke causing fasciolosis.Despite the significant economic and public health impacts of F.gigantica,there are few studies on the pathogenesis of this parasite and our understanding is further limited by the lack of genome and transcriptome information.Therefore,it is necessary to investigate yak infection with F.hepatica in China and analyze the mRNA transcriptome and miRnome of different development stages of F.gigantica.In the present study,we investigated the seroprevalence of F.hepatica infection in yaks by ELISA in Maqu County,Luqu County and Tianzhu County,Gansu Province,China.Furthermore,Using RNA-Seq and bioinformatics analysis,differentially expressed genes of different development stages of F.gigantica were identified.(1)The overall F.hepatica seroprevalence was 28.7%(454/1,584),with 29.2% in white yaks(284/974)and 27.9% in black yaks(170/610).Interestingly,season and age of yak were associated with F.hepatica infection in yaks in the investigated areas.(2)Using RNA-Seq technique and bioinformatics analysis,we examined the transcriptomes of different development stages of F.gigantica and identified differentially expressed genes in these development stages.A total of 319261 unigenes were produced from juvenile and adult stages of F.gigantica,with an average length of 1038 nucleotides(nt)and N50 of 1552 nt.A total of 153573(48.1%)unigenes were annotated by BLAST similarity searches against the NCBI non-redundant protein database.Of these unigenes,122405(38.34%),35756(11.91%),32384(10.14%),66543(20.84%),86211(27%),86793(27.18%)and 48889(15.31%)had significant similarity in the NCBI non-redundant protein,non-redundant nucleotide,KEGG ortholog,Swiss-Prot,Protein family,Gene Ontology and eukaryotic Ortholog Groups databases,respectively.Moreover,large numbers of differentially expressed genes were identified in different development groups,29183 in the group of Fg-2(miracidia)vs Fg-1(egg),27341 in Fg-3(redia)vs Fg-2(miracidia),323075 in Fg-5(cercariae)vs Fg-3(redia),16388 in Fg-6(metacercariae)vs Fg-5(cercariae),30601 in Fg-42d(juveniles of 42 days)vs Fg-6(metacercariae),42 in Fg-70d(juveniles of 70 days)vs Fg-42d(juveniles of 42 days)and 3947 in Fg-98d(adults)vs Fg-70d(juveniles of 70 days).Through GO and KEGG pathways analyses,we identified two egg-laying-associated pathways: cGMP-PKG signaling pathway and TGF-? signaling pathway.(3)Using RNA-Seq technique and bioinformatics analysis,we examined the miRnome of different development stages of F.gigantica.A total of 160 differentially expressed miRNAs were identified from different development stages of F.gigantica,with 69 in the group of Fg-2(miracidia)vs Fg-1(egg),59 in Fg-3(redia)vs Fg-2(miracidia),95 in Fg-5(cercariae)vs Fg-3(redia),44 in Fg-6(metacercariae)vs Fg-5(cercariae),95 in Fg-42d(juveniles of 42 days)vs Fg-6(metacercariae),35 in Fg-70d(juveniles of 70 days)vs Fg-42d(juveniles of 42 days)and 39 in Fg-98d(adults)vs Fg-70d(juveniles of 70 days).Through GO and KEGG pathways analyses,two miRNAs(namely,sja-miR-1 and sja-miR-7-5p)related sexual maturity were identified.(4)We performed correlation analysis between transcriptomes and mi Rnome of different development stages of F.gigantica and identified large numbers of differentially expressed genes targeted by differentially expressed miRNAs.Of these,8868 were in the group of Fg-2(miracidia)vs Fg-1(egg),7792 in Fg-3(redia)vs Fg-2(miracidia),11646 in Fg-5(cercariae)vs Fg-3(redia),3025 in Fg-6(metacercariae)vs Fg-5(cercariae),11760 in Fg-42d(juveniles of 42 days)vs Fg-6(metacercariae),14 in Fg-70d(juveniles of 70 days)vs Fg-42d(juveniles of 42 days)and 1097 in Fg-98d(adults)vs Fg-70d(juveniles of 70 days).In conclusion,we firstly investigated the seroprevalence of F.hepatica infection in yaks by ELISA in Maqu County,Luqu County and Tianzhu County,Gansu Province,China.Moreover,we studied the transcriptomic and miRnomic profiles of different development stages of F.gigantica by an integrated approach using RNA-Seq and bioinformatics analysis for the first time.We also performed correlation analysis between transcriptomes and miRnomes of different development stages of F.gigantica.These results provide solid bases for better understanding of the epidemiology of fascioliasis in animals and for the elucidation of the infectivity and pathogenesis of this important parasite.