The Multi-omics Research Of The Liver For Yaks Infected With Fascioliasis

Yak is a unique species of livestock and play an important part of livestock industry on the Tibetan plateau.Due to the semi-wild grazing form for yak,it is highly susceptible to diseases and causes serious economic losses for yak farming.Fascioliasis is a foodborne parasitic disease caused by Fasciola hepatica and Fasciola gigantica in the liver and bile ducts of yaks,which could lead to wasting,loss of productivity and even death for yaks.At present,a lot of studies had been reported on trematodes,including omic-studies on trematodes and hosts.However,there was a lack of information on the liver of yaks after Fasciola infection.In this study,we determined the type of Fasciola infection of yak by mitochondrial genome sequencing,and the transcripts,protein profiles and metabolites in the liver of yaks after Fasciola infection by next-generation sequencing,iTRAQ,and non-targeted metabolism,and explored the interaction between Fasciola and yaks using combined multi-omics analysis.The results are as follows:(1)The mitochondrial genome of Fasciola from yak contained 36 typical mitochondrial genes: 12 PCGs(cox1-3,nad1-6,nad4 L,cob,and atp6),22 tRNA genes,and 2 rRNA genes(rrnS and rrnL).The nucleotide composition of the mitochondrial genome was A =15.17%,T = 48.02%,G = 27.51%,and C = 9.31%,and AT-skew was 63.19%.The mitochondrial genome of Fasciola encodes a total of 2716 amino acids,the most commonly used amino acids were Leu(16.72%),followed by Val(12.74%),Phe(10.90%),Ser(10.09%)and Gly(8.39%).The phylogenetic tree analysis showed that the Fasciola from yak was in the same branch as the "intermediate" Fasciola.(2)There were 1296 differentially expressed genes in the liver of yaks infected with Fasciola including 738 significantly up-regulated genes and 556 significantly down-regulated.There were significantly down-regulated expression genes related to drug metabolism(such as cytochrome P450),cholesterol,bile acid,fatty acid synthesis and metabolism.Fasciola could achieve immune evasion after suppressing the expression of IL-17 family genes.by suppressing the antigen processing and presentation pathways.There were 27 up-regulated expression genes related to cancer including 9 up-regulated expression genes about hepatocellular carcinoma.(3)There were 1404 differentially expressed proteins of which 1005 proteins were significantly up-regulated and 399 proteins were significantly down-regulated.It was confirmed at the protein level that Fasciola infection leads to impaired liver function with the significant down-regulation proteins related to drug metabolism and cholesterol,bile acid,fatty acid synthesis and metabolism.p38 was activates by TAK1 though phosphorylating MKK3/6,and p-p38 plays an important role in immune and inflammatory responses.(4)Compared with normal yak livers,84 differential metabolites were detected in ESI+,Among them,62 differential metabolites were significantly upregulated and 22 differential metabolites were significantly downregulated in the yak livers infected Fasciola.ESI-detected 88 differential metabolites,of which 58 differential metabolites were significantly upregulated and 30 differential metabolites were significantly downregulated.After Fasciola infection,the liver function of yaks was impaired,the drug and toxicant content was significantly increased in the liver.The fat metabolic process and the enterohepatic circulation of bile acids were disrupted,resulting in the accumulation of TG and bile in the liver.(5)CYP7A1 was significant down-regulation expression and affected cholesterol metabolism due to bile sludge caused by Fasciola infection in yaks.L-FABP was significantly down-regulates expression after bile sludge.In the absence of L-FABP,TG level was increased in the liver via lipid metabolism and free fatty acid homeostasis was impaired leading to fatty liver even liver fibrosis and cirrhosis.After Fasciola infection,12(S)-HETE was significantly up-regulates expression via arachidonic acid metabolism to promote the phosphorylation of p38 to p-p38,which is involved in a variety of immune and inflammatory pathways to generate multiple cytokines.CYP1A1 was significantly down-regulates expression which could reduce the production of 12(S)-HETE after Fasciola infection,while Doramapimple level was significantly increased in the liver.The phosphorylation of p38 was inhibited due to the high Doramapimod level and the low CYP1A1 level,which interferes with the immune inflammatory response of the organism.In conclusion,the study obtained the molecular characteristics of the mitochondrial genome of Fasciola from yaks and determined the infected type.The transcriptomic,proteomic and metabolomic data of liver from were obtained,and the way of damage by Fasciola infection on yaks was investigated at three levels: genes,proteins and metabolites.Fasciola may inhibit p38 phosphorylation to achieve immune evasion.Our research provided a basis for the subsequent study of the interaction between Fasciola and yaks.