Differential effects of low and high doses of lipoteichoic acid on lipopolysaccharide-induced interleukin-6 production.
OBJECTIVE
Interleukin-6 (IL-6), which is increased in patients who are suffering from septic shock, is an important mediator of the inflammatory response. Here, we examined the priming effect of lipoteichoic acid (LTA) and lipopolysaccharide (LPS) on IL-6 production in a monocyte-like cell line.


METHODS
THP-1 cells were primed by treatingwith a low or high dose of LTA isolated from Staphylococcus aureus (aLTA) and then re-treated with LPS. IL-6 production, receptor expression, and the variation of signaling molecules were examined by ELISA, reverse transcriptase polymerase chain reaction, and western blotting, respectively.


RESULTS
LPS-mediated IL-6 production was dramatically increased in THP-1 cells pretreated with a low dose aLTA, while it was significantly decreased when a high dose of aLTA was given along with LPS. LPS-induced IL-6 production in low dose aLTA priming cells mediated by NF-κB and MAPKs pathways, and Akt functioned as a negative regulator of IL-6 production. Together, the results of this study suggest that different doses of bacterial cell surface components can mediate a diverse range of responses with respect to inflammatory cytokine production.
Department of Internal Medicine, Saint Louis University, St. Louis, MO, 63104, USA.
Hangeun
H
Kim
Bong Jun
BJ
Jung
Joo Yun
JY
Kim
Dae Kyun
DK
Chung
D045744:Cell Line, Tumor; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D048191:Lactiplantibacillus plantarum; D008070:Lipopolysaccharides / Q000008:administration & dosage*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D013211:Staphylococcus aureus; D013682:Teichoic Acids / Q000008:administration & dosage*
C508600:IL6 protein, human; D015850:Interleukin-6; D008070:Lipopolysaccharides; D016328:NF-kappa B; D013682:Teichoic Acids; C009900:lipoteichoic acid; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases