Identification and characterization of SKAT-2, a novel Th2-specific zinc finger gene (original) (raw)
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Journal of immunology (Baltimore, Md. : 1950), 1998
We have shown previously that human CD4+ 45RO- T cells could be primed for a Th2 phenotype independent of IL-4 if they were activated by anti-CD28 mAb plus IL-2. If additional TCR signals were provided, the cells differentiated toward Th1 independent of IL-12. Here we show that anti-CD28/IL-2-primed Th2 cells expressed high levels of activated STAT6, but no cytokine mRNA. Moreover, both Th1 and Th2 cells expressed active STAT1 and -3, but not STAT2, -4, and -5. Restimulation of Th1 or Th2 cells via CD3 plus CD28 induced production of IFN-gamma or IL-4, respectively, but did not alter the activation status/DNA binding activity of STATs. Addition of IL-4 (or anti-IL-4 mAb) to restimulated Th2 cells did not modulate STAT6 activation or IL-4 expression, confirming the full commitment. However, Th2 cells remained responsive to IL-12, which repressed STAT6 DNA binding but activated STAT4, and this coincided with a suppression of IL-4/IL-5 and an induction of IFN-gamma. In Th1 cells, IL-12...
In vivo studies fail to reveal a role for IL4 or STAT6 signaling in Th2 lymphocyte differentiation
Proceedings of The National Academy of Sciences, 2008
The expression of interleukin-4 (IL-4) is viewed as the hallmark of a Th2 lymphocyte, whereas the subsequent action of IL-4 and IL-13, mediated through the STAT6 signaling pathway, is seen as a prerequisite for the full development of Th2 immune responses to parasites and allergens. G4 mice, whose IL-4 gene locus contains the fluorescent reporter eGFP, were used to quantify the number of Th2 cells that develop during Nippostrongylus brasiliensis-or allergen-induced immune responses under conditions where IL-4 or STAT6 was absent. Here, we show that deletion of IL-4 or STAT6 had little impact on the number or timing of appearance of IL-4-producing Th2 cells. These data indicate that in vivo differentiation of naïve CD4 T cells to Th2 status often occurs independently of IL-4 and STAT6 and that recently described pathways of Th2 cell differentiation may explain how allergens and parasites selectively induce Th2-mediated immunity.
Identification of Novel IL-4/Stat6-Regulated Genes in T Lymphocytes
The Journal of Immunology, 2003
IL-4, primarily produced by T cells, mast cells, and basophiles, is a cytokine which has pleiotropic effects on the immune system. IL-4 induces T cells to differentiate to Th2 cells and activated B lymphocytes to proliferate and to synthesize IgE and IgG1. IL-4 is particularly important for the development and perpetuation of asthma and allergy. Stat6 is the protein activated by signal transduction through the IL-4R, and studies with knockout mice demonstrate that Stat6 is critical for a number of IL-4-mediated functions including Th2 development and production of IgE. In the present study, novel IL-4-and Stat6-regulated genes were discovered by using Stat6 ؊/؊ mice and Affymetrix oligonucleotide arrays. Genes regulated by IL-4 were identified by comparing the gene expression profile of the wild-type T cells induced to polarize to the Th2 direction (CD3/CD28 activation ؉ IL-4) to gene expression profile of the cells induced to proliferate (CD3/CD28 activation alone). Stat6-regulated genes were identified by comparing the cells isolated from the wild-type and Stat6 ؊/؊ mice; in this experiment the cells were induced to differentiate to the Th2 direction (CD3/CD28 activation ؉ IL-4). Our study demonstrates that a number a novel genes are regulated by IL-4 through Stat6-dependent and -independent pathways. Moreover, elucidation of kinetics of gene expression at early stages of cell differentiation reveals several genes regulated rapidly during the process, suggesting their importance for the differentiation process.
2002
IL-4 is a multifunctional cytokine whose secretion displays important immunomodulatory functions. Its expression is regulated at the level of transcription, and one of the main factors involved is NFAT. The IL-4-induced transcription factor Stat6 is required for the development of naive T cells into Th2 phenotype, capable of secreting IL-4. However, IL-4 production by differentiated Th2 cells is IL-4 independent; thus, it remains unclear whether Stat6 plays any role in the IL-4 expression by mature Th2 cells. We have analyzed in the Th2 clone D10.G4.1 the nuclear proteins able to bind the regulatory element P1 of the IL-4 promoter. Gel-shift assays show NFAT1 as the most abundant nuclear protein that binds to P1 after ionomycin plus PMA activation, whereas Stat6 accounts for the bulk of the P1 binding in the presence of exogenous IL-4. Reporter experiments agree with an inhibitory effect of Stat6 on the NFAT1-induced transcriptional activity directed by the P1 element. CD3 signaling leads to an early induction of NFAT1-P1 complexes correlating with a strong induction of the IL-4 gene. In later phases of CD3 activation, P1 is also bound by Stat6 and a fall in the IL-4 mRNA levels takes place. These two late events during CD3 activation were found to be sensible in experiments conducted with an anti-IL-4 Ab. These results suggest that IL-4 endogenously produced by Th2 cells under TCR triggering modulates its own expression through Stat6.
Stat6-Independent GATA-3 Autoactivation Directs IL-4-Independent Th2 Development and Commitment
Immunity, 2000
1997). Previously, we presented evidence that Th2 cells Washington University School of Medicine can develop from naive T cells independently of IL-4 St. Louis, Missouri 63110 produced by non-T cells (Schmitz et al., 1994), sug-† Deutsches Rheumaforschungszentrum gesting either that naive T cells are capable of autono-Hannoversche Strasse 27 mous IL-4 production or that non-IL-4 signals can direct 10115 Berlin Th2 development. However, a mechanistic explanation Germany for factor-independent IL-4 production by naive T cells ‡ Miltenyi Biotec was not available at that time. Friedrich-Ebert-Strasse 68 The transcription factors GATA-3 and c-Maf are selec-51429 Bergisch Gladbach tively expressed in type 2 Th cells (Ho et al., 1996; Zhang Germany et al., 1997; Zheng and Flavell, 1997). Transgenic § Department of Experimental Rheumatology GATA-3 overexpression increases Th2 cytokine produc-Charite tion, and antisense-GATA-3 blockade reduces Th2 cyto-Humboldt University kines in Th2 clones (Zheng and Flavell, 1997). GATA-3 10115 Berlin activates the IL-5 promoter (Zhang et al., 1997), and Germany GATA-3-dependent enhancer activity has been found within several regions surrounding the IL-4 gene (Ranganath et al., 1998). GATA-3 expression by retrovirus in Summary developing Th1 cells blocks IL-12 receptor expression and prevents Th1 development independently of the The initial source of IL-4-inducing Th2 development induction of IL-4 (Ouyang et al., 1998). c-Maf directly and the mechanism of stable Th2 commitment remain augments IL-4 promoter activity through cooperative obscure. We found the reduced level of IL-4 production interactions with Nip-45, NF-AT (Ho et al., 1996, 1998), in Stat6-deficient T cells to be significantly higher than and JunB (Rincon et al., 1997b). Transgenic c-Maf overin Th1 controls. Using a novel cell surface affinity maexpression increases IL-4 and alters the isotype patterns trix technique, we found that IL-4-secreting Stat6-defiof antibody with increased IgE (Ho et al., 1998), and cient T cells stably expressed GATA-3 and Th2 phenoc-Maf-deficient T cells show a selective reduction in type. Introducing GATA-3 into Stat6-deficient T cells IL-4 but not other Th2-specific cytokines (Kim et al., completely restored Th2 development, inducing c-Maf, 1999a, 1999b). Th2-specific DNase I hypersensitive sites in the IL-4 While these studies have added to our understanding locus, and Th2 cytokine expression. The fact that of cytokine gene regulation, much less is known about GATA-3 fully reconstitutes Th2 development in Stat6how GATA-3 and c-Maf expression themselves are regudeficient T cells indicates it is a master switch in Th2 lated. In naive T cells, these factors are expressed at development. Finally, GATA-3 exerts Stat6-indepenlow levels, which increase over the first week of Th2 dent autoactivation, creating a feedback pathway stadevelopment (Ho et al., 1996; Zhang et al., 1997; Zheng bilizing Th2 commitment. and Flavell, 1997; Ouyang et al., 1998). The pathways and controlling elements directing their Th2-specific