Modulation of astrocyte inducible nitric oxide synthase and cytokine expression by interferon beta is associated with induction and inhibition of interferon gamma-activated sequence binding activity.
Although interferon (IFN)-beta is firmly established as a therapeutic agent for multiple sclerosis, information regarding its role in astrocyte cytokine production is limited. In primary cultures of human astrocytes, we determined the effects of IFN-beta on astrocyte cytokine [tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6] and inducible nitric oxide synthase (iNOS) expression by ribonuclease protection assay and ELISA. We found that IFN-beta inhibited astrocyte cytokine/iNOS induced by IL-1 plus IFN-gamma, but in the absence of IFN-gamma, IFN-beta enhanced IL-1-induced cytokine/iNOS expression. Electrophoretic mobility shift analysis (EMSA) demonstrated that IFN-gamma induced sustained IFN-gamma-activated sequence (GAS) binding, while IFN-beta induced transient GAS binding. When used together, IFN-beta inhibited IFN-gamma-induced GAS binding activity. Nuclear factor-kappa B (NF-kappaB) activation was not altered by either IFNs, whereas IFN stimulated response element (ISRE) was only activated by IFN-beta and not IFN-gamma. These results suggest that IFN-beta can both mimic and antagonize the effect of IFN-gamma by modulating induction of nuclear GAS binding activity. Our results demonstrating differential regulation of astrocyte cytokine/iNOS induction by IFN-beta are novel and have implications for inflammatory diseases of the human CNS.
Hua
Liwei L
LL
Department of Pathology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Kim
Mee-Ohk
MO
Brosnan
Celia F
CF
Lee
Sunhee C
SC
D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D016899:Interferon-beta / Q000494:pharmacology*; D007371:Interferon-gamma / Q000378:metabolism / Q000494:pharmacology*; D007375:Interleukin-1 / Q000494:pharmacology; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D023282:Nuclease Protection Assays; D012333:RNA, Messenger / Q000378:metabolism; D020218:Response Elements / Q000187:drug effects / Q000502:physiology; D050794:STAT1 Transcription Factor; D050795:STAT2 Transcription Factor; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism
D016207:Cytokines; D004268:DNA-Binding Proteins; D007375:Interleukin-1; D015850:Interleukin-6; D012333:RNA, Messenger; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D050795:STAT2 Transcription Factor; D015534:Trans-Activators; D014409:Tumor Necrosis Factor-alpha; D016899:Interferon-beta; D007371:Interferon-gamma; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II