Aberrant expression of IFN-c in Th2 cells from Th2 LCR-deficient mice Soo Seok Hwang, Kiwan Kim, Wonyong Lee, Gap Ryol Lee ⇑ Department of Life Science, Sogang University, Seoul 121-742, Republic of Korea article info Article history: Received 25 June 2012 Available online 3 July 2012 Keywords: IFN-c Th2 LCR GATA-3 STAT6 Gene expression Chromatin remodeling Th2 differentiation abstract The Th2 locus control region (LCR) has been shown to be a crucial cis-acting element for Th2 cytokine expression and Th2 cell differentiation. To study the role of Th2 LCR in ifng locus regulation, we examined the expression of IFN-c in Th2 cells from Th2 LCR-deficient mice. We found IFN-c to be aberrantly up-reg- ulated. In addition, histone 3(H3)-acetylation and histone 3 lysine 4 (H3-K4)-methylation greatly increased at the ifng locus of the Th2 cells. GATA-3 and STAT6 bound to the ifng promoter in Th2 cells from the wild type but not from the Th2 LCR-deficient mice, and they directly repressed ifng expression in transient reporter assay. Moreover, ectopic expression of GATA-3 and STAT6-VT repressed the aberrant expression of the ifng gene and restored repressive chromatin state at the ifng locus in Th2 cells from Th2 LCR-deficient mice. These results suggest that expression of the ifng gene and chromatin remodeling of the ifng locus are under the control of a Th2 LCR-mediated Th2 differentiation program. Ó 2012 Elsevier Inc. All rights reserved. 1. Introduction CD4 T cells play important roles in coordination of a variety of immune responses against various pathogens. Several subsets of CD4 T cells, including Th1, Th2, Th9 and Th17 cells, are differenti- ated from common naive CD4 T cells by T cell receptor (TCR) stim- ulation and by the influence of appropriate cytokines [1–6]. Th1 cells produce IFN-c and mediate cellular immunity against intra- cellular bacteria; Th2 cells produce IL-4, IL-5, and IL-13, and medi- ate anti-parasite response and also activate B cells, which aid in humoral immune response against extracellular pathogens. Th17 cells produce IL-17A, IL-17F, and IL-22 and mediate immunity against extracellular bacteria and fungi, facilitating inflammation by recruiting neutrophils to inflammation sites. The effector CD4 T cells also cause immunopathologic diseases; Th2 cells cause allergic diseases, and Th1 and Th17 cells play a critical role in some autoimmune and inflammatory diseases. Different signal transduction pathways and transcription factors play a role in their differentiation to each subset of effector CD4 T cells [1–6]. Th1 cells are induced by IL-12 and IFN-c, which activate STAT4 and STAT1, respectively, and induce T-bet. Th2 cells are induced by IL-4, which activates STAT6 and induces GATA-3. GATA-3 has been shown to be an essential transcription factor for Th2 differentiation. It is selectively expressed in Th2 cells and induces Th2 cell differentiation [7]. When GATA-3 is ectopically expressed in Th1 cells, it induces il4 expression and chromatin remodeling at the Th2 cytokine locus, which contains the il4, il5, and il13 genes. [8–10]. Deletion of the gata3 gene in the mouse genome causes complete inhibition of Th2 cell differentiation [11–13]. GATA-3 has been shown to not only induce the Th2 cell program but also block differentiation into other T helper cell types including Th1 and Th17 [14,15]. Although, the function of GATA-3 in Th2 differentiation is well-known, its mechanisms of GATA-3 in chromatin remodeling and in cytokine gene expression are poorly understood. The expression of subset-specific cytokines is crucial for the dif- ferentiation and function of T helper cells. Regulation of the expres- sion of these cytokines has been intensively studied as a model system for gene regulation during cell differentiation [16,17]. In particular, the Th2 cytokine locus has been well studied in the as- pects of the gene expression and epigenetic mechanisms underly- ing cell differentiation [16,17]. Likewise, the ifng locus also has been well studied to understand the regulation of gene expression and epigenetic modifications in Th1 cells [6,14,16,18]. Many of the cis-elements for regulation of Th2 cytokine genes in the Th2 locus have been identified and studied. These include promoters, enhanc- ers, a silencer, and a Th2 locus control region [16,17]. Among these elements, the Th2 LCR has been shown to coordinately regulate Th2 cytokine genes [16,17]. The Th2 LCR is composed of 4 DNase I hypersensitive sites that are highly conserved between species [19,20]. Th2 LCR-harboring transgenic mice render high-level, dif- ferentiation-specific, and copy number-dependent expression to linked transgenes [21]. The Th2 LCR undergoes Th2-specific histone acetylation and DNA methylation during Th2 cell differentiation [16,17]. It has been shown to associates with promoters of the il4, 0006-291X/$ - see front matter Ó 2012 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.bbrc.2012.06.146 ⇑ Corresponding author. Address: Department of Life Science, Sogang University, 1 Shinsu-dong, Mapo-ku, Seoul 121-742, Republic of Korea. Fax: +82 2 704 3601. E-mail address: grlee@sogang.ac.kr (G.R. Lee). Biochemical and Biophysical Research Communications 424 (2012) 512–518 Contents lists available at SciVerse ScienceDirect Biochemical and Biophysical Research Communications journal homepage: www.elsevier.com/locate/ybbrc