title: Differential response of bovine mammary epithelial cells to Staphylococcus aureus or Escherichia coli agonists of the innate immune system.
abstract: Mastitis caused by Escherichia coli and Staphylococcus aureus is a major pathology of dairy cows. To better understand the differential response of the mammary gland to these two pathogens, we stimulated bovine mammary epithelial cells (bMEC) with either E. coli crude lipopolysaccharide (LPS) or with S. aureus culture supernatant (SaS) to compare the transcriptomic profiles of the initial bMEC response. By using HEK 293 reporter cells for pattern recognition receptors, the LPS preparation was found to stimulate TLR2 and TLR4 but not TLR5, Nod1 or Nod2, whereas SaS stimulated TLR2. Biochemical analysis revealed that lipoteichoic acid, protein A and α-hemolysin were all present in SaS, and bMEC were found to be responsive to each of these molecules. Transcriptome profiling revealed a core innate immune response partly shared by LPS and SaS. However, LPS induced expression of a significant higher number of genes and the fold changes were of greater magnitude than those induced by SaS. Microarray data analysis suggests that the activation pathways and the early chemokine and cytokine production preceded the defense and stress responses. A major differential response was the activation of the type I IFN pathway by LPS but not by SaS. The higher upregulation of chemokines (Cxcl10, Ccl2, Ccl5 and Ccl20) that target mononuclear leucocytes by LPS than by SaS is likely to be related to the differential activation of the type I IFN pathway, and could induce a different profile of the initial recruitment of leucocytes. The MEC responses to the two stimuli were different, as LPS was associated with NF-κB and Fas signaling pathways, whereas SaS was associated with AP-1 and IL-17A signaling pathways. It is noteworthy that at the protein level secretion of TNF-α and IL-1β was not induced by either stimulus. These results suggest that the response of MEC to diffusible stimuli from E. coli and S. aureus contributes to the onset of the response with differential leucocyte recruitment and distinct inflammatory and innate immune reactions of the mammary gland to infection.
authors.affiliation: INRA, UMR1282, ISP, F 37380, Nouzilly, France. pascal.rainard@tours.inra.fr.
authors.forename: Florence B
authors.initials: FB
authors.lastname: Gilbert
authors.forename: Patricia
authors.initials: P
authors.lastname: Cunha
authors.forename: Kirsty
authors.initials: K
authors.lastname: Jensen
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Glass
authors.forename: Gilles
authors.initials: G
authors.lastname: Foucras
authors.forename: Christèle
authors.initials: C
authors.lastname: Robert-Granié
authors.forename: Rachel
authors.initials: R
authors.lastname: Rupp
authors.forename: Pascal
authors.initials: P
authors.lastname: Rainard
mesh_terms: D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D018925:Chemokines / Q000235:genetics / Q000378:metabolism; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D004847:Epithelial Cells / Q000276:immunology / Q000382:microbiology; D004926:Escherichia coli / Q000502:physiology; D004927:Escherichia coli Infections / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D005260:Female; D020869:Gene Expression Profiling / Q000662:veterinary; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D007113:Immunity, Innate; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000502:physiology; D008321:Mammary Glands, Animal / Q000276:immunology* / Q000382:microbiology; D008414:Mastitis, Bovine / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D053472:Nod Signaling Adaptor Proteins / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis / Q000662:veterinary; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D015398:Signal Transduction; D013203:Staphylococcal Infections / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000502:physiology; D051193:Toll-Like Receptors / Q000235:genetics* / Q000378:metabolism
chemical_list: D018925:Chemokines; D016207:Cytokines; D047908:Intracellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides; D053472:Nod Signaling Adaptor Proteins; D051193:Toll-Like Receptors