University at Buffalo - The State University of New York
Skip to Content
Actinobacillus actinomycetemcomitans lipopolysaccharide induces interleukin-6 expression through multiple mitogen-activated protein kinase pathways... - PubMed - NCBI
Format

Send to

Choose Destination
See comment in PubMed Commons below
Oral Microbiol Immunol. 2006 Dec;21(6):392-8.

Actinobacillus actinomycetemcomitans lipopolysaccharide induces interleukin-6 expression through multiple mitogen-activated protein kinase pathways in periodontal ligament fibroblasts.

Author information

1
Department of Oral Biology, State University of New York at Buffalo, Buffalo, NY, USA.

Abstract

Actinobacillus actinomycetemcomitans plays a major role in the pathogenesis of aggressive periodontitis. Lipopolysaccharide (LPS) derived from A. actinomycetemcomitans is a key factor in inflammatory cytokine generation within periodontal tissues. In this study, we identify major mitogen-activated protein kinase (MAPK) signaling pathways induced by A. actinomycetemcomitans LPS, Escherichia coli LPS and interleukin-1beta (IL-1beta) in a murine periodontal ligament (mPDL) fibroblast cell line. Immunoblot analysis was used to assess the phosphorylated forms of p38, extracellular-regulated kinase (ERK) and c-jun N-terminal kinase (JNK) MAPK following stimulation with A. actinomycetemcomitans LPS, E. coli LPS and IL-1beta. IL-6 mRNA induction was detected via reverse transcription-polymerase chain reaction, while protein levels were quantified via enzyme-linked immunosorbent assays (ELISA). We utilized biochemical inhibitors of p38, ERK and JNK MAPK to identify the MAPK signaling pathways needed for IL-6 expression. Additional use of stable mPDL cell lines containing dominant negative mutant constructs of MAPK kinase-3 and -6 (MKK-3/6) and p38 null mutant mouse embryonic fibroblast (MEF) cells were used to substantiate the biochemical inhibitor data. Blocking p38 MAPK with SB203580 reduced the induction of IL-6 mRNA by A. actinomycetemcomitans LPS, E. coli LPS and IL-1beta by >70%, >95% and approximately 60%, respectively. IL-6 ELISA indicated that blocking p38 MAPK reduced the IL-6 protein levels induced by A. actinomycetemcomitans LPS, E. coli LPS and IL-1beta by approximately 60%, approximately 50% and approximately 70%, respectively. All MAPK inhibitors significantly reduced the IL-6 protein levels induced by A. actinomycetemcomitans LPS, E. coli LPS and IL-1beta whereas only p38 inhibitors consistently reduced the A. actinomycetemcomitans LPS, E. coli LPS and IL-1beta induction of IL-6 mRNA steady-state levels. The contribution of p38 MAPK LPS-induced IL-6 expression was confirmed using MKK-3/6 dominant negative stable mPDL cell lines. Wild-type and p38alpha(-/-) MEF cells provided additional evidence to support the role of p38alpha MAPK in A. actinomycetemcomitans LPS-stimulated IL-6. Our results indicate that induction of IL-6 by E. coli LPS, IL-1beta and A. actinomycetemcomitans LPS requires signaling through MKK-3-p38alpha ERK, JNK and p38 MAPK in mPDL cells.

[Indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Wiley Icon for MLibrary (Deep Blue)
    Loading ...
    Support Center