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Interferon-gamma-induced MD-2 protein expression and lipopolysaccharide (LPS) responsiveness in corneal epithelial cells is mediated by Janus tyrosine kinase-2 activation and direct binding of STAT1 protein to the MD-2 promoter.

ABSTRACT: The inability of epithelial cells from the cornea and other tissues to respond to LPS is reportedly due to low expression of the TLR4 co-receptor MD-2. We generated MD-2(-/-) bone marrow chimeras, and showed that MD-2 expression on non-myeloid cells was sufficient to mediate LPS-induced corneal inflammation. As IFN-? is produced during Pseudomonas aeruginosa corneal infection, we examined the role of this cytokine on MD-2 expression by primary human corneal epithelial (HCE) cells and HCE cell lines. Exogenous IFN-? was found to induce MD-2 mRNA, MD-2 cell surface expression, and LPS responsiveness as determined by p65 translocation to the nucleus and production of IL-6, CXCL1, and CXCL8/IL-8. Incubation with either the AG490 JAK2 inhibitor or with STAT1 siRNA blocked STAT1 phosphorylation and MD-2 transcription. Furthermore, EMSA analysis demonstrated that STAT1 binds to the MD-2 promoter, indicating that STAT1 is an MD-2 transcription factor. Together, these findings demonstrate that IFN-? induces MD-2 expression and LPS responsiveness in HCE cells by JAK-2-dependent STAT1 activation and direct binding to the MD-2 promoter. Furthermore, given our findings on LPS-induced corneal inflammation, it is likely that IFN-?-induced MD-2 expression by corneal epithelial cells contributes to the host response in vivo, determining the extent of tissue damage and bacterial clearance.

SUBMITTER: Roy S

PROVIDER: S-EPMC3129156 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature

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Interferon-gamma-induced MD-2 protein expression and lipopolysaccharide (LPS) responsiveness in corneal epithelial cells is mediated by Janus tyrosine kinase-2 activation and direct binding of STAT1 protein to the MD-2 promoter.

Roy Sanhita S Sun Yan Y Pearlman Eric E

The Journal of biological chemistry 20110513 27

The inability of epithelial cells from the cornea and other tissues to respond to LPS is reportedly due to low expression of the TLR4 co-receptor MD-2. We generated MD-2(-/-) bone marrow chimeras, and showed that MD-2 expression on non-myeloid cells was sufficient to mediate LPS-induced corneal inflammation. As IFN-γ is produced during Pseudomonas aeruginosa corneal infection, we examined the role of this cytokine on MD-2 expression by primary human corneal epithelial (HCE) cells and HCE cell li ...[more]

PMID: 21572044

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Dataset Information

Interferon-gamma-induced MD-2 protein expression and lipopolysaccharide (LPS) responsiveness in corneal epithelial cells is mediated by Janus tyrosine kinase-2 activation and direct binding of STAT1 protein to the MD-2 promoter.

Publications

Interferon-gamma-induced MD-2 protein expression and lipopolysaccharide (LPS) responsiveness in corneal epithelial cells is mediated by Janus tyrosine kinase-2 activation and direct binding of STAT1 protein to the MD-2 promoter.

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