Abstract
Microglial cells (MC) are IL-12 producers in the central nervous system. Here, we found that IL-12 receptor subunits beta1 and beta2 were both constitutively expressed, and up-regulated by IFN-gamma, in human primary MC. IL-12p70, after binding to its receptor, is internalized into vesicles that qualify as early endosomes as indicated by intracellular colocalization with transferrin. IL-12 induced tyrosine phosphorylation and nuclear translocation of STAT4. IL-12 signaling in human MC also involved members of the NFkappaB family. IL-12p70 and, more effectively, the combination of IL-12p70 and IFN-gamma, induced IL-12p40 mRNA expression and bioactive IL-12p70 production. Human MC, thus, express a functional IL-12 receptor and produce bioactive IL-12 following IL-12 stimulation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Cell Nucleus / metabolism
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Cells, Cultured
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DNA-Binding Proteins / metabolism
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Endosomes / metabolism
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Gene Expression Regulation
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Humans
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Interferon-gamma / pharmacology
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Interleukin-12 / biosynthesis
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Interleukin-12 / pharmacology*
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Microglia / drug effects*
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Microglia / metabolism
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NF-kappa B / physiology
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Phosphorylation
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Protein Subunits
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RNA, Messenger / analysis
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Receptors, Interleukin / analysis*
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Receptors, Interleukin / genetics
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Receptors, Interleukin-12
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STAT4 Transcription Factor
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Trans-Activators / metabolism
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Tyrosine / metabolism
Substances
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DNA-Binding Proteins
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IL12RB1 protein, human
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IL12RB2 protein, human
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NF-kappa B
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Protein Subunits
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RNA, Messenger
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Receptors, Interleukin
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Receptors, Interleukin-12
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STAT4 Transcription Factor
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STAT4 protein, human
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Trans-Activators
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Interleukin-12
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Tyrosine
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Interferon-gamma