Comparative Proteomic Investigation On Liver And Spleen Tissues Of Bos Taurus And Bos Indicus

Domestic cattle consists of two main types-Bos taurus and Bos indicus.Beyond marked morphological differences,there exist local adaptation,behavior and disease resistance differences between B.taurus and B.indicus.Previous studies had demonstrated that B.indicus exhibits higher resistance to theileriosis and tick than B.taurus,while B.taurus possesses higher resistance to trypanosomiasis than B.indicus.However,less is known about the genetic basis underlying such disease resistance differences.To address this issue,the present study was to investigate the differentially expressed proteins(DEPs)in liver and spleen tissues between B.taurus and B.indicus,aiming to dissect the genetic basis of disease resistance differences between the two groups at proteomics level.The DEPs in liver and spleen tissues between B.taurus and B.indicus were detected by iTRAQ mass spectrometry.The liver and spleen samples of B.taurus were set as control group.There were 197(including 127 up-and 70 down-regulated proteins)and 142(including 77 up-and 65 down-regulated proteins)DEPs obtained in liver and spleen tissues of B.taurus and B.indicus,respectively Gene ontology(GO)enrichment analysis showed that the DEPs were mainly related to carboxylic acid decomposition,organic acid decomposition and small molecule decomposition in liver group and histone H3-K27 trimethylation,nucleosome selection and injury reaction in spleen group.The immune-related items were immune response,immunoglobulin complex,immunoglobulin receptor binding,etc,Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis of DEPs suggested that 15 pathways associated to metabolism were significantly(p-value<0.05)enriched in the liver tissue,such as tryptophan metabolic pathway,beta-alanine metabolic pathway,lysine degradation pathway,etc.KEGG pathways of spleen were mainly enriched in the protein digestion and absorption pathway,extracellular matrix receptor and lysozyme.The DEPs in both tissues were enriched in the metabolic pathways of trypanosomiasis and protozoan diseases.Through GO and KEGG Enrichment analyses,the immune-related DEPs(including E1BPE1,PJ8,Q08DQ4 and Q08DZ5 in the liver tissue,and P15497,P02453,F6QPE0 and Q1RMT8 in spleen tissue)that detected in the liver and spleen tissue were associated to trypanosomiasis and protozoon.These proteins may be directly or indirectly be involved in immune response in the form of enzymes.Predicting the correlation between these DEPs and disease resistance differences between the two types of cattle,involving one up-regulated(E1BPE1)and three down-regulated(Q1JPJ8,P15497 and Q1RMT8)DEPs were participated in the trypanosomiasis pathway;this may be the major factor influencing the weak resistance to trypanosomiasis in B.indicus.PRM(parallel reaction monitoring)validation analysis on 12 DEPs showed that the results were consistent with those of iTRAQ,indicating that the expressed proteins of liver and spleen tissues were highly credible.This study would provide a scientific basis and key technical support for screening potential disease-related biomarkers.