Project description:Bovine mastitis remains a primary focus of dairy cattle disease research due to its considerable negative economic impact on the dairy industry. This was the first differential proteomic study aimed to identify milk somatic cell proteins contributing to host defense and their variable responses to naturally occurring mastitis in Sahiwal (Bos indicus) cows. To accomplish this, indigenous Sahiwal cows were categorized based on milk somatic cell counts (SCC)< 2×105cells/mL with no previous history of mastitis as healthy (H) animals. However, cows with sub-clinically mammary infection (SCM) and clinical mastitis (CM) had milk SCC 2-5×105 and > 5×105 cells/mL, respectively. The milk somatic cells were isolated and analysed using a label-free quantitative, liquid chromatography- mass spectrometry (LC-MS/MS) proteomic approach. In total, 3896, 3843 and 3868 proteins showed significant differential abundance between CM vs SCM, CM vs H and SCM vs H groups, respectively (=1 high-quality PSM/s, =1 unique peptide, FDR < 0.01), while 25, 53, 21 proteins were unique to CM, SCM and H groups, respectively. The differentially abundant proteins (DAPs) top significantly (p<0.05) upregulated proteins were annexin A5 (ANXA5), Rho-associated protein kinase 2 (ROCK2) and hepsin (HPN) in CM vs SCM groups, whereas vanin 2 (VNN2), thioredoxin reductase-like selenoprotein T (SELENOT), ceramidase (NAAA), lymphocyte antigen 75 (LY75/CD 205), cysteine-rich PDZ-binding protein (CRIPT), misshapen like kinase 1 (MINK1), macrophage scavenger receptor (MSR1/CD204), leupaxin (LPXN) and lipoamide acyltransferase (DBT) were upregulated common to both CM vs H and SCM vs H groups. These upregulated differentially abundant proteins (DAPs) are mainly associated with host immune functions of the mammary gland during mastitis. Besides this, the top downregulated proteins such as cortactin (CTTN), glutathione S-transferase (GSTM3), G protein-coupled receptor class C group 5 member B (GPRC5B), signal-induced proliferation-associated protein 1 (SPIA1), the exocyst complex component 6 (EXOC3), S100 A16. Additionally, the findings of the GO and KEGG enrichment functional analysis demonstrated Staphylococcus aureus infection, neutrophil extracellular trap formation, extracellular matrix receptor interaction, complement and coagulation cascades, toll-like and NOD-like receptor, PPAR, MAPK signalling, IL-17 signalling, Th1 and Th2 cell differentiation, Fc gamma mediated phagocytosis, cell adhesion molecules, peroxisome, lysosome, endocytosis were the enriched pathways of immune mechanisms regulating during naturally infected mastitis. These findings provide essential information on mammary infection-associated proteomic profiling in milk somatic cells and associated host immune response mechanisms which uncover potential biomarkers for detecting subclinical mastitis in dairy cattle.
2025-05-06 | PXD045487 | Pride