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Functional Crosstalk between Type I and II Interferon through the Regulated Expression of STAT1.
- Source :
-
PLoS Biology . May2010, Vol. 8 Issue 5, p1-12. 12p. 1 Diagram, 7 Graphs. - Publication Year :
- 2010
-
Abstract
- Autocrine priming of cells by small quantities of constitutively produced type I interferon (IFN) is a well-known phenomenon. In the absence of type I IFN priming, cells display attenuated responses to other cytokines, such as anti-viral protection in response to IFNc. This phenomenon was proposed to be because IFNa/b receptor1 (IFNAR1) is a component of the IFNc receptor (IFNGR), but our new data are more consistent with a previously proposed model indicating that regulated expression of STAT1 may also play a critical role in the priming process. Initially, we noticed that DNA binding activity of STAT1 was attenuated in c-Jun-/- fibroblasts because they expressed lower levels of STAT1 than wild-type cells. However, expression of STAT1 was rescued by culturing c-Jun-/- fibroblasts in media conditioned by wild-type fibroblasts suggesting they secreted a STAT1-inducing factor. The STAT1-inducing factor in fibroblast-conditioned media was IFNb, as it was inhibited by antibodies to IFNAR1, or when IFNb expression was knocked down in wild-type cells. IFNAR1-/- fibroblasts, which cannot respond to this priming, also expressed reduced levels of STAT1, which correlated with their poor responses to IFNc. The lack of priming in IFNAR1-/- fibroblasts was compensated by over-expression of STAT1, which rescued molecular responses to IFNγ and restored the ability of IFNγ to induce protective anti-viral immunity. This study provides a comprehensive description of the molecular events involved in priming by type I IFN. Adding to the previous working model that proposed an interaction between type I and II IFN receptors, our work and that of others demonstrates that type I IFN primes IFNc-mediated immune responses by regulating expression of STAT1. This may also explain how type I IFN can additionally prime cells to respond to a range of other cytokines that use STAT1 (e.g., IL-6, M-CSF, IL-10) and suggests a potential mechanism for the changing levels of STAT1 expression observed during viral infection. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 15449173
- Volume :
- 8
- Issue :
- 5
- Database :
- Academic Search Index
- Journal :
- PLoS Biology
- Publication Type :
- Academic Journal
- Accession number :
- 50467608
- Full Text :
- https://doi.org/10.1371/journal.pbio.1000361