Exogenous Ceramide-1-phosphate Reduces Lipopolysaccharide (LPS)-mediated Cytokine Expression.
Summary of "Exogenous Ceramide-1-phosphate Reduces Lipopolysaccharide (LPS)-mediated Cytokine Expression."
Toll-like receptor 4 (TLR4) is a component of the innate immune system that recognizes a diverse group of molecular structures, such as lipopolysaccharide (LPS) from Gram-negative bacteria. TLR4 signaling ultimately leads to activation of the transcription factor, nuclear factor κB (NF-κB), and the production of cytokines. Ceramide is a bioactive sphingolipid that has been suggested to regulate TLR4-induced NF-κB signaling, although reports on the role of ceramide in TLR4 activation conflict. We investigated the possibility that ceramide metabolites, such as ceramide-1-phosphate (C-1-P), may explain these discrepancies. We now report that exogenous C-1-P, but not ceramide, reduces NF-κB-mediated gene transcription in HEK 293 cells stably transfected with human TLR4, CD14, and MD-2. We demonstrate that inhibition of NF-κB by exogenous C-1-P is dose-dependent and specific to TLR4 in a reporter assay. We further demonstrate a requirement for both the phosphate moiety and the sphingoid backbone to inhibit LPS-activated NF-κB transcription. Specifically, C-1-P prevents the degradation of IκB, the phosphorylation of the p65 subunit of NF-κB, and LPS-stimulated MAPK activation. The functional consequence of C-1-P inhibition of NF-κB is a reduction in LPS-mediated cytokine release from HEK 293 TLR4-expressing cells and human peripheral blood mononuclear cells. Taken together, these data demonstrate that C-1-P may function as an anti-inflammatory lipid mediator of immune response.
From the Departments of Pharmacology and.
This article was published in the following journal.
Name: The Journal of biological chemistry
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/22065582
- DOI: http://dx.doi.org/10.1074/jbc.M111.264010
Medical and Biotech [MESH] Definitions
Stat Transcription Factors
A family of transcription factors containing SH2 DOMAINS that are involved in CYTOKINE-mediated SIGNAL TRANSDUCTION. STAT transcription factors are recruited to the cytoplasmic region of CELL SURFACE RECEPTORS and are activated via PHOSPHORYLATION. Once activated they dimerize and translocate into the CELL NUCLEUS where they influence GENE expression. They play a role in regulating CELL GROWTH PROCESSES and CELL DIFFERENTIATION. STAT transcription factors are inhibited by SUPPRESSOR OF CYTOKINE SIGNALING PROTEINS and PROTEIN INHIBITORS OF ACTIVATED STAT.
Suppressor Of Cytokine Signaling Proteins
A family of structurally related proteins that are induced by CYTOKINES and negatively regulate cytokine-mediated SIGNAL TRANSDUCTION PATHWAYS. SOCS proteins contain a central SH2 DOMAIN and a C-terminal region of homology known as the SOCS box.
Any compound containing one or more monosaccharide residues bound by a glycosidic linkage to a hydrophobic moiety such as an acylglycerol (see GLYCERIDES), a sphingoid, a ceramide (CERAMIDES) (N-acylsphingoid) or a prenyl phosphate. (From IUPAC's webpage)
Cytokine Receptor Gp130
A cytokine receptor that acts through the formation of oligomeric complexes of itself with a variety of CYTOKINE RECEPTORS.
Gene Knock-in Techniques
Techniques used to add in exogenous gene sequence such as mutated genes; REPORTER GENES, to study mechanisms of gene expression; or regulatory control sequences, to study effects of temporal changes to GENE EXPRESSION.
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