The Differentially Expressed Protein Analysis Of Staphylococcus Aureus Artificial Induced Mastitis In Dairy Cow Based On The ITRAQ Technology

Mastitis is a complex disease in dairy cow, leading to low production and great economic losses. The disease seriously damages the healthy development of dairy industry. Mastitis caused by Staphylococcus aureus, with the high cost of therapy and difficult in cure, is the most serious mammary gland disease. For now, there is no easy way to solve this disease.In this study, S. aureus was administered to establish a disease model of clinical mastitis. Using iTRAQ and LC-MS technology, the differentially expressed proteins related to S. aureus mastitis compared to healthy control in dairy cow were screened. Following by GO and Pathway analysis, novel biomarkers associated with mastitis were obtained, which could initially reveal the immune regulation mechanism of mastitis at the protein level. The main results were as follows:1. The mastitis model induced by S. aureus was successfully established. After administration, the clinical symptoms of cows and the detection index (SCC, BMT, etc) truly reflected the pathogenic process of S. aureus-induced mastitis.2.168 differentially expressed proteins were screened by iTRAQ (Fold change≥ 1.5 or≤ 0.667, p-value< 0.05), of which 66 proteins were up-regulated and 102 were down-regulated in S. aureus group. Bioinformatics analysis exposed that 30 differentially expressed proteins were related with defenses, immune and inflammatory responses in breast tissue.3. The GO analysis of differentially expressed proteins found that these proteins were significantly enriched in 314 GO Terms (p-value< 0.05).4.20 pathways related with defense, immune and inflammatory were screened by pathway analysis with KEGG database of differentially expressed proteins. The results are as follows:Fc epsilon RI signaling pathway, MAPK signaling pathway, NF-kappa B signaling pathway, B cell receptor signaling pathway, Calcium signaling pathway, Toll-like receptor signaling pathway, Natural killer cell mediated cytotoxicity, VEGF signaling pathway, Leukocyte transendothelial migration Hematopoietic cell lineage, Intestinal immune network for IgA production, Chemokine signaling pathway, Phosphatidylinositol signaling system, Cytosolic DNA-sensing pathway, Fc gamma R-mediated phagocytosis, Complement and coagulation cascades, T cell receptor signaling pathway, RIG-I-like receptor signaling pathway, NOD-like receptor signaling pathway, Antigen processing and presentation. With further network diagram analysis of these pathways,12 hub proteins were screened, such as predicted platelet basic protein, IHIH3, HSPB1, HSPA1A, NFKB1, LBP, RAC2, predicted copine-3 isoform X1, ISOC1, LOC524810, ITGAM, and ITGB2. These key proteins could be initially used as mastitis resistance selected candidate proteins for further research.