Monocyte chemoattractant protein-1 expression by osteoblasts following infection with Staphylococcus aureus or Salmonella.
Two common pathogens of bone, Staphylococcus aureus and Salmonella, were investigated for their ability to induce chemokine expression in bone-forming osteoblasts. Cultured mouse or human osteoblasts could rapidly respond to bacterial infection by upregulating the mRNA encoding the chemokine, monocyte chemoattractant protein-1 (MCP-1). This rapid induction occurred on infection with either the gram-positive pathogen, S. aureus, or the gram-negative pathogen, Salmonella. Increased mRNA expression translated into MCP-1 secretion by cultured mouse or human osteoblasts in response to viable bacteria, whereas UV-killed bacteria were less effective in stimulating chemokine secretion. There was a dose-response relationship observed between the amount of input bacteria and increases in MCP-1 secretion. Immunohistochemical staining of infected osteoblasts indicated that the majority of cells could express MCP-1, with some osteoblasts having a higher intensity of staining than others. Organ cultures of mouse calvaria (skullcap) bone showed increases in MCP-1 immunostaining following bacterial infection. The immunoreactive MCP-1 in infected calvaria localized to areas containing active osteoblasts. Taken together, these studies demonstrate a conserved osteoblast-derived MCP-1 response to two very different pathogens of bone.
Bost
K L
KL
Department of Biology, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223-0001, USA. klbost@email.unc.edu
Bento
J L
JL
Petty
C C
CC
Schrum
L W
LW
Hudson
M C
MC
Marriott
I
I
D000818:Animals; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009924:Organ Culture Techniques; D010006:Osteoblasts / Q000378:metabolism* / Q000382:microbiology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000378:metabolism; D019779:Salmonella enterica / Q000276:immunology*; D013211:Staphylococcus aureus / Q000276:immunology*
D018932:Chemokine CCL2; D012333:RNA, Messenger