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Genetic susceptibility to S. aureus mastitis in sheep: differential expression of mammary epithelial cells in response to live bacteria or supernatant

Bonnefont, Cécile and Rainard, Pascal and Cunha, Patricia and Gilbert, Florence B. and Toufeer, Mehdi and Aurel, Marie-Rose and Rupp, Rachel and Foucras, Gilles Genetic susceptibility to S. aureus mastitis in sheep: differential expression of mammary epithelial cells in response to live bacteria or supernatant. (2012) Physiological Genomics, 44 (7). 403-416. ISSN 1094-8341

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Official URL: http://dx.doi.org/10.1152/physiolgenomics.00155.2011


Staphylococcus aureus is a prevalent pathogen for mastitis in dairy ruminants and is responsible for both clinical and subclinical mastitis. Mammary epithelial cells (MEC) represent not only a physical barrier against bacterial invasion but are also active players of the innate immune response permitting infection clearance. To decipher their functions in general and in animals showing different levels of genetic predisposition to Staphylococcus in particular, MEC from ewes undergoing a divergent selection on milk somatic cell count were stimulated by S. aureus. MEC response was also studied according to the stimulation condition with live bacteria or culture supernatant. The early MEC response was studied during a 5 h time course by microarray to identify differentially expressed genes with regard to the host genetic background and as a function of the conditions of stimulation. In both conditions of stimulation, metabolic processes were altered, the apoptosis-associated pathways were considerably modified, and inflammatory and immune responses were enhanced with the upregulation of il1a, il1b, and tnfa and several chemokines known to enhance neutrophil (cxcl8) or mononuclear leukocyte (ccl20) recruitment. Genes associated with oxidative stress were increased after live bacteria stimulation, whereas immune responserelated genes were higher after supernatant stimulation in the early phase. Only 20 genes were differentially expressed between Staphylococcus spp-mastitis resistant and susceptible animals without any clearly defined role on the control of infection. To conclude, this suggests that MEC may not represent the cell type at the origin of the difference of mastitis susceptibility, at least as demonstrated in our genetic model. Supernatant or heat-killed S. aureus produce biological effects that are essentially different from those induced by live bacteria.

Item Type:Article
HAL Id:hal-02647022
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Université de Toulouse > Ecole Nationale Vétérinaire de Toulouse - ENVT (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
French research institutions > Institut National de la Recherche Agronomique - INRA (FRANCE)
Other partners > Université de Tours (FRANCE)
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Deposited On:28 Oct 2013 13:52

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