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IL-21-mediated non-canonical pathway for IL-1β production in conventional dendritic cells.

Wan CK, Li P, Spolski R, Oh J, Andraski AB, Du N, Yu ZX, Dillon CP, Green DR, Leonard WJ - Nat Commun (2015)

Bottom Line: IL-21 does not induce Il1b expression in CD4(+) T cells, with differential histone marks present in these cells versus cDCs.IL-21-induced IL-1β processing in cDCs does not require caspase-1 or caspase-8 but depends on IL-21-mediated death and activation of serine protease(s).These results demonstrate lineage-restricted IL-21-induced IL-1β via a non-canonical pathway and provide evidence for its importance in vivo.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular Immunology and the Immunology Center, National Heart, Lung and Blood Institute, National Institutes of Health, 10 Center Drive, Building 10, Room 7B05, Bethesda, Maryland 20892-1674 USA.

ABSTRACT
The canonical pathway for IL-1β production requires TLR-mediated NF-κB-dependent Il1b gene induction, followed by caspase-containing inflammasome-mediated processing of pro-IL-1β. Here we show that IL-21 unexpectedly induces IL-1β production in conventional dendritic cells (cDCs) via a STAT3-dependent but NF-κB-independent pathway. IL-21 does not induce Il1b expression in CD4(+) T cells, with differential histone marks present in these cells versus cDCs. IL-21-induced IL-1β processing in cDCs does not require caspase-1 or caspase-8 but depends on IL-21-mediated death and activation of serine protease(s). Moreover, STAT3-dependent IL-1β expression in cDCs at least partially explains the IL-21-mediated pathologic response occurring during infection with pneumonia virus of mice. These results demonstrate lineage-restricted IL-21-induced IL-1β via a non-canonical pathway and provide evidence for its importance in vivo.

No MeSH data available.


Related in: MedlinePlus

Cell type-specific expression of Il1b and Il21 genes correlates with the differential STAT3 binding and enhancer landscapes.(a) Freshly isolated cDCs were rested 1 h, then stimulated with IL-21 for 4 h; CD4+ T cells were pre-activated for 3 days, then washed and rested 16 h, and stimulated with IL-21 for 4 h. Shown are genes differentially regulated by IL-21 in cDCs versus pre-activated CD4+ T cells. For cDCs, gene expression profiling was performed by microarray analysis, where cDCs were pooled from three independent experiments, as described in ref. 16. For pre-activated CD4+ T cells, gene expression profiling data were generated by RNA-Seq analysis. Shown are data from one of two similar experiments. (b) Il1b and Il21 expression in cDCs and CD4+ T cells not treated or stimulated with IL-21 as in a. Data are representative of 3 experiments. Error bars are technical duplicates of the representative experiment. (c,d) STAT3 binding, H3K4me1, H3K27ac, H3K4me3, and H3K27me3 marks at the Il1b locus in cDCs (c) and CD4+ T cells (d). Arrows in c indicate STAT3 binding sites at GAS1, GAS2 and GAS3 regions (GAS1: TTAgggGAA (−155 bp), TACcctGAA (−175 bp), TCCctgGAA (−195 bp); GAS2: TTTgggGAA (−2,452 bp), TTCctcCAA (−2,525 bp), TTCttcAAA (−2,549 bp); GAS3: TTGtgtGAA (−9,761 bp)). Arrows in d indicate the STAT3 binding sites identified in cDCs, but no STAT3 binding was seen at these sites in CD4+ T cells. (e,f) STAT3 binding, H3K4me1, H3K27ac, H3K4me3 and H3K27me3 marks at the Il21 gene locus in cDCs (e) and CD4+ T cells (f). Arrow in f indicates the STAT3 binding site at the GAS motif in the Il21 promoter region. Arrow in e indicates this same site, but no STAT3 binding was seen at this site in cDCs. Data are representative of two experiments. Statistical analysis was performed by Student's t-test.
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f4: Cell type-specific expression of Il1b and Il21 genes correlates with the differential STAT3 binding and enhancer landscapes.(a) Freshly isolated cDCs were rested 1 h, then stimulated with IL-21 for 4 h; CD4+ T cells were pre-activated for 3 days, then washed and rested 16 h, and stimulated with IL-21 for 4 h. Shown are genes differentially regulated by IL-21 in cDCs versus pre-activated CD4+ T cells. For cDCs, gene expression profiling was performed by microarray analysis, where cDCs were pooled from three independent experiments, as described in ref. 16. For pre-activated CD4+ T cells, gene expression profiling data were generated by RNA-Seq analysis. Shown are data from one of two similar experiments. (b) Il1b and Il21 expression in cDCs and CD4+ T cells not treated or stimulated with IL-21 as in a. Data are representative of 3 experiments. Error bars are technical duplicates of the representative experiment. (c,d) STAT3 binding, H3K4me1, H3K27ac, H3K4me3, and H3K27me3 marks at the Il1b locus in cDCs (c) and CD4+ T cells (d). Arrows in c indicate STAT3 binding sites at GAS1, GAS2 and GAS3 regions (GAS1: TTAgggGAA (−155 bp), TACcctGAA (−175 bp), TCCctgGAA (−195 bp); GAS2: TTTgggGAA (−2,452 bp), TTCctcCAA (−2,525 bp), TTCttcAAA (−2,549 bp); GAS3: TTGtgtGAA (−9,761 bp)). Arrows in d indicate the STAT3 binding sites identified in cDCs, but no STAT3 binding was seen at these sites in CD4+ T cells. (e,f) STAT3 binding, H3K4me1, H3K27ac, H3K4me3 and H3K27me3 marks at the Il21 gene locus in cDCs (e) and CD4+ T cells (f). Arrow in f indicates the STAT3 binding site at the GAS motif in the Il21 promoter region. Arrow in e indicates this same site, but no STAT3 binding was seen at this site in cDCs. Data are representative of two experiments. Statistical analysis was performed by Student's t-test.

Mentions: The ChIP-Seq results prompted us to determine whether differential STAT3 binding could explain the cell type-specific functions of IL-21 in cDCs and CD4+ T cells. Therefore, we compared IL-21-induced gene regulation in these cells, and we found that these STAT3 binding differences correlated with differential IL-21-induced gene expression in cDCs versus CD4+ T cells (Fig. 4a) (for example, IL-21 could induce Il1b in cDCs but not CD4+ T cells, whereas it induced Il21 in CD4+ T cells but not in cDCs (Fig. 4a,b). Interestingly, analysis revealed IL-21-induced STAT3 binding in cDCs at the Il1b promoter and 5′ upstream region (Fig. 4c) to GAS-like motifs (Supplementary Table 1), with enriched H3K4me1 and H3K27ac marks at those sites (Fig. 4c), whereas STAT3 did not bind to these sites in CD4+ T cells and active enhancer marks were correspondingly absent (Fig. 4d). Conversely, for the Il21 gene, in cDCs, where the gene is not expressed, neither STAT3 nor H3K4me1/H3K27ac marks were found at the promoter region after IL-21 stimulation (Fig. 4e), but IL-21-activated STAT3 bound to the Il21 promoter region in CD4+ T cells, which express the gene, with enrichment of H3K4me1 and H3K27ac marks (Fig. 4f). Thus, gene expression correlated with the active enhancer landscapes and IL-21-induced STAT3 binding in cDCs versus CD4+ T cells. Moreover, we found IL-21-induced H3K4me3 at the Il1b promoter (indicating an open chromatin structure20) in cDCs where Il1b is expressed (Fig. 4c) but not in CD4+ T cells where it is not (Fig. 4d); conversely H3K4me3 was strongly present at the Il21 promoter in CD4+ T cells where Il21 is expressed (Fig. 4f), but not in cDCs where it is not (Fig. 4e). Interestingly, Il1b is one of only 24 genes in which we observed much higher H3K4me3 in cDCs than in CD4+ T cells (Supplementary Fig. 4). The presence of H3K27me3 repressive marks (indicative of inactive genes20) at the Il1b locus in CD4+ T cells and Il21 locus in cDCs corresponded to the non-expression of these genes in these cell types. Interestingly, the Il21 locus in CD4+ T cells exhibited both H3K27me3 and H3K4me3 marks (Fig. 4f), indicative of a bivalent gene poised for induction or repression22.


IL-21-mediated non-canonical pathway for IL-1β production in conventional dendritic cells.

Wan CK, Li P, Spolski R, Oh J, Andraski AB, Du N, Yu ZX, Dillon CP, Green DR, Leonard WJ - Nat Commun (2015)

Cell type-specific expression of Il1b and Il21 genes correlates with the differential STAT3 binding and enhancer landscapes.(a) Freshly isolated cDCs were rested 1 h, then stimulated with IL-21 for 4 h; CD4+ T cells were pre-activated for 3 days, then washed and rested 16 h, and stimulated with IL-21 for 4 h. Shown are genes differentially regulated by IL-21 in cDCs versus pre-activated CD4+ T cells. For cDCs, gene expression profiling was performed by microarray analysis, where cDCs were pooled from three independent experiments, as described in ref. 16. For pre-activated CD4+ T cells, gene expression profiling data were generated by RNA-Seq analysis. Shown are data from one of two similar experiments. (b) Il1b and Il21 expression in cDCs and CD4+ T cells not treated or stimulated with IL-21 as in a. Data are representative of 3 experiments. Error bars are technical duplicates of the representative experiment. (c,d) STAT3 binding, H3K4me1, H3K27ac, H3K4me3, and H3K27me3 marks at the Il1b locus in cDCs (c) and CD4+ T cells (d). Arrows in c indicate STAT3 binding sites at GAS1, GAS2 and GAS3 regions (GAS1: TTAgggGAA (−155 bp), TACcctGAA (−175 bp), TCCctgGAA (−195 bp); GAS2: TTTgggGAA (−2,452 bp), TTCctcCAA (−2,525 bp), TTCttcAAA (−2,549 bp); GAS3: TTGtgtGAA (−9,761 bp)). Arrows in d indicate the STAT3 binding sites identified in cDCs, but no STAT3 binding was seen at these sites in CD4+ T cells. (e,f) STAT3 binding, H3K4me1, H3K27ac, H3K4me3 and H3K27me3 marks at the Il21 gene locus in cDCs (e) and CD4+ T cells (f). Arrow in f indicates the STAT3 binding site at the GAS motif in the Il21 promoter region. Arrow in e indicates this same site, but no STAT3 binding was seen at this site in cDCs. Data are representative of two experiments. Statistical analysis was performed by Student's t-test.
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f4: Cell type-specific expression of Il1b and Il21 genes correlates with the differential STAT3 binding and enhancer landscapes.(a) Freshly isolated cDCs were rested 1 h, then stimulated with IL-21 for 4 h; CD4+ T cells were pre-activated for 3 days, then washed and rested 16 h, and stimulated with IL-21 for 4 h. Shown are genes differentially regulated by IL-21 in cDCs versus pre-activated CD4+ T cells. For cDCs, gene expression profiling was performed by microarray analysis, where cDCs were pooled from three independent experiments, as described in ref. 16. For pre-activated CD4+ T cells, gene expression profiling data were generated by RNA-Seq analysis. Shown are data from one of two similar experiments. (b) Il1b and Il21 expression in cDCs and CD4+ T cells not treated or stimulated with IL-21 as in a. Data are representative of 3 experiments. Error bars are technical duplicates of the representative experiment. (c,d) STAT3 binding, H3K4me1, H3K27ac, H3K4me3, and H3K27me3 marks at the Il1b locus in cDCs (c) and CD4+ T cells (d). Arrows in c indicate STAT3 binding sites at GAS1, GAS2 and GAS3 regions (GAS1: TTAgggGAA (−155 bp), TACcctGAA (−175 bp), TCCctgGAA (−195 bp); GAS2: TTTgggGAA (−2,452 bp), TTCctcCAA (−2,525 bp), TTCttcAAA (−2,549 bp); GAS3: TTGtgtGAA (−9,761 bp)). Arrows in d indicate the STAT3 binding sites identified in cDCs, but no STAT3 binding was seen at these sites in CD4+ T cells. (e,f) STAT3 binding, H3K4me1, H3K27ac, H3K4me3 and H3K27me3 marks at the Il21 gene locus in cDCs (e) and CD4+ T cells (f). Arrow in f indicates the STAT3 binding site at the GAS motif in the Il21 promoter region. Arrow in e indicates this same site, but no STAT3 binding was seen at this site in cDCs. Data are representative of two experiments. Statistical analysis was performed by Student's t-test.
Mentions: The ChIP-Seq results prompted us to determine whether differential STAT3 binding could explain the cell type-specific functions of IL-21 in cDCs and CD4+ T cells. Therefore, we compared IL-21-induced gene regulation in these cells, and we found that these STAT3 binding differences correlated with differential IL-21-induced gene expression in cDCs versus CD4+ T cells (Fig. 4a) (for example, IL-21 could induce Il1b in cDCs but not CD4+ T cells, whereas it induced Il21 in CD4+ T cells but not in cDCs (Fig. 4a,b). Interestingly, analysis revealed IL-21-induced STAT3 binding in cDCs at the Il1b promoter and 5′ upstream region (Fig. 4c) to GAS-like motifs (Supplementary Table 1), with enriched H3K4me1 and H3K27ac marks at those sites (Fig. 4c), whereas STAT3 did not bind to these sites in CD4+ T cells and active enhancer marks were correspondingly absent (Fig. 4d). Conversely, for the Il21 gene, in cDCs, where the gene is not expressed, neither STAT3 nor H3K4me1/H3K27ac marks were found at the promoter region after IL-21 stimulation (Fig. 4e), but IL-21-activated STAT3 bound to the Il21 promoter region in CD4+ T cells, which express the gene, with enrichment of H3K4me1 and H3K27ac marks (Fig. 4f). Thus, gene expression correlated with the active enhancer landscapes and IL-21-induced STAT3 binding in cDCs versus CD4+ T cells. Moreover, we found IL-21-induced H3K4me3 at the Il1b promoter (indicating an open chromatin structure20) in cDCs where Il1b is expressed (Fig. 4c) but not in CD4+ T cells where it is not (Fig. 4d); conversely H3K4me3 was strongly present at the Il21 promoter in CD4+ T cells where Il21 is expressed (Fig. 4f), but not in cDCs where it is not (Fig. 4e). Interestingly, Il1b is one of only 24 genes in which we observed much higher H3K4me3 in cDCs than in CD4+ T cells (Supplementary Fig. 4). The presence of H3K27me3 repressive marks (indicative of inactive genes20) at the Il1b locus in CD4+ T cells and Il21 locus in cDCs corresponded to the non-expression of these genes in these cell types. Interestingly, the Il21 locus in CD4+ T cells exhibited both H3K27me3 and H3K4me3 marks (Fig. 4f), indicative of a bivalent gene poised for induction or repression22.

Bottom Line: IL-21 does not induce Il1b expression in CD4(+) T cells, with differential histone marks present in these cells versus cDCs.IL-21-induced IL-1β processing in cDCs does not require caspase-1 or caspase-8 but depends on IL-21-mediated death and activation of serine protease(s).These results demonstrate lineage-restricted IL-21-induced IL-1β via a non-canonical pathway and provide evidence for its importance in vivo.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular Immunology and the Immunology Center, National Heart, Lung and Blood Institute, National Institutes of Health, 10 Center Drive, Building 10, Room 7B05, Bethesda, Maryland 20892-1674 USA.

ABSTRACT
The canonical pathway for IL-1β production requires TLR-mediated NF-κB-dependent Il1b gene induction, followed by caspase-containing inflammasome-mediated processing of pro-IL-1β. Here we show that IL-21 unexpectedly induces IL-1β production in conventional dendritic cells (cDCs) via a STAT3-dependent but NF-κB-independent pathway. IL-21 does not induce Il1b expression in CD4(+) T cells, with differential histone marks present in these cells versus cDCs. IL-21-induced IL-1β processing in cDCs does not require caspase-1 or caspase-8 but depends on IL-21-mediated death and activation of serine protease(s). Moreover, STAT3-dependent IL-1β expression in cDCs at least partially explains the IL-21-mediated pathologic response occurring during infection with pneumonia virus of mice. These results demonstrate lineage-restricted IL-21-induced IL-1β via a non-canonical pathway and provide evidence for its importance in vivo.

No MeSH data available.


Related in: MedlinePlus