Response of the goat mammary gland to infection with Staphylococcus aureus revealed by gene expression profiling in milk somatic and white blood cells

Abstract

BackgroundS. aureus is one of the main pathogens responsible for the intra-mammary infection in dairy ruminants. Although much work has been carried out to understand the complex physiological and cellular events that occur in the mammary gland in response to S. aureus, the protective mechanisms are still poorly understood. The objectives of the present study were to investigate gene expression during the early response of the goat mammary gland to an experimental challenge with S. aureus, in order to better understand the local and systemic response and to compare them in two divergent lines of goat selected for high and low milk somatic cell scores.ResultsNo differences in gene expression were found between high and low SCS (Somatic Cells Score) selection lines. Analysing the two groups together, an expression of 300 genes were found to change from T0 before infection, and T4 at 24 hours and T5 at 30 hours following challenge. In blood derived white blood cells 8 genes showed increased expression between T0 and T5 and 1 gene has reduced expression. The genes showing the greatest increase in expression following challenge (5.65 to 3.16 fold change) play an important role in (i) immune and inflammatory response (NFKB1, TNFAIP6, BASP1, IRF1, PLEK, BATF3); (ii) the regulation of innate resistance to pathogens (PTX3); and (iii) the regulation of cell metabolism (CYTH4, SLC2A6, ARG2). The genes with reduced expression (−1.5 to −2.5 fold) included genes involved in (i) lipid metabolism (ABCG2, FASN), (ii) chemokine, cytokine and intracellular signalling (SPPI), and (iii) cell cytoskeleton and extracellular matrix (KRT19).ConclusionsAnalysis of genes with differential expression following infection showed an inverse relationship between immune response and lipid metabolism in the early response of the mammary gland to the S. aureus challenge. PTX3 showed a large change in expression in both milk and blood, and is therefore a candidate for further studies on immune response associated with mastitis.

Is total RNA extraction possible from small volume goat milk (7.5 mL) for RT-qPCR studies?

“…Studies conducted so far about cell extraction from milk (2,4,7,14,17) reported that large amounts of milk (50 mL-1000 mL) was required. However, since there are risks related to sterility and degradation in RNA studies, magnitude of milk volumes creates significant problems in transferring the samples from the farm to the laboratory.…”

“…In this context, researchers who had conducted studies both on breast tissue and on somatic cells reported that milk somatic cells can be used as RNA source in the analysis of lipogenic activities of the tissue (14). Generally, most of the studies about RNA extraction from milk somatic cells were conducted on goats (2,4,10), cows (7,14,17,20) and sheep (13) milks. Total milk volume to extract RNA from milk somatic cells changes between 50 mL-1000 mL in different studies.…”

Influencia de la infección subclínica por agentes de la fiebre por garrapatas en vacas lecheras

“…The same authors also stated that most leukocytes are mobilized from the bloodstream into the mammary tissue after changes in the capillary permeability. Milk from cows with intramammary infections may show increased numbers of immune cells, leading to a predomination of neutrophils, followed by macrophages and lymphocytes, while the number of epithelial cells remains unchanged (12,13). Previous study showed that bovine viral diarrhea affects SCC (8), the lack of information concerning infectious diseases motivated the present study on the relationship between milk composition and quality on dairy cattle with tick fever.…”

“…In Argentina, it has been reported that dairy cows experimentally infected by an attenuated strain of A. marginale showed reduction of milk production, as well as fever, sanguíneo hacia el tejido mamario tras cambios en la permeabilidad capilar. La leche de vacas con infecciones intra-mamarias puede presentar un mayor número de células inmunes, lo que lleva a un predominio de neutrófilos, seguido por macrófagos y linfocitos, mientras que el número de células epiteliales permanece sin cambios (12,13). Un estudio anterior mostró que la diarrea viral bovina afecta el valor de SCC (8); la falta de información respecto a las enfermedades infecciosas motivó el presente estudio sobre la relación entre la composición y calidad de la leche en el ganado lechero con fiebre por garrapatas.…”

Molecular characterization of interferon regulatory factor 1 in Bubalus bubalis

“…For example, the IRF1 gene in pigs is overexpressed in endometrial cells during the peri-implantation period, which contributes to establishing successful pregnancy (Joyce et al, 2007). In goats, studies that examined immune response to mammary gland infection with Staphylococcus aureus showed a high increase in IRF1 gene expression compared with other genes that are related to innate resistance to pathogens (Cremonesi et al, 2012).…”