The capacity of bovine endothelial cells to eliminate intracellular Staphylococcus aureus and Staphylococcus epidermidis is increased by the proinflammatory cytokines TNF-alpha and IL-1beta.
Staphylococcus aureus is a pathogenic bacterium causing clinical and subclinical bovine mastitis. Infections of the udder by S. aureus are frequently associated with the presence of Staphylococcus epidermidis, an opportunistic pathogen. We reported previously that the capacity of bovine endothelial cells (BEC) to endocytize S. aureus is associated with the activation of NF-kappaB and modulated by the proinflammatory cytokines TNF-alpha and IL-1beta. In this work, we explore the ability of BEC to eliminate intracellular S. aureus and S. epidermidis and their response to these cytokines. Time-kinetics survival experiments indicated that BEC eliminate intracellular S. epidermidis more efficiently. Replication of S. aureus, but not S. epidermidis, inside BEC was evident by an increase in intracellular bacteria recovered at 2 h postinfection. Afterwards, the intracellular number of staphylococci decreased gradually, reaching the lowest value at 24 h. Treatment of BEC with TNF-alpha or IL-1beta potentiated the capacity of BEC to eliminate both Staphylococcus species at the times tested. These results indicate that activation of the intrinsic antistaphylococcal response in BEC, enhanced by TNF-alpha and IL-1beta, is effective to eliminate S. aureus and S. epidermidis and suggest that endothelial cells may play a prominent role in the defense against infections caused by these bacteria.
Oviedo-Boyso
Javier
J
Centro Multidisciplinario de Estudios en Biotecnología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, México.
Cardoso-Correa
Bernardo I
BI
Cajero-Juárez
Marcos
M
Bravo-Patiño
Alejandro
A
Valdez-Alarcón
Juan J
JJ
Baizabal-Aguirre
Víctor M
VM
D000818:Animals; D002417:Cattle; D002461:Cell Line, Transformed; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000276:immunology* / Q000382:microbiology*; D053583:Interleukin-1beta / Q000276:immunology / Q000494:pharmacology*; D008414:Mastitis, Bovine / Q000276:immunology / Q000382:microbiology; D013203:Staphylococcal Infections / Q000382:microbiology / Q000662:veterinary; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification / Q000472:pathogenicity; D013212:Staphylococcus epidermidis / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification / Q000472:pathogenicity; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000494:pharmacology*
D053583:Interleukin-1beta; D014409:Tumor Necrosis Factor-alpha