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IL-1β promotes Th17 differentiation by inducing alternative splicing of FOXP3.

Mailer RK, Joly AL, Liu S, Elias S, Tegner J, Andersson J - Sci Rep (2015)

Bottom Line: FOXP3 is not only expressed by Treg cells but is also transiently expressed when naïve T cells differentiate into Th17 cells.Forced splicing of FOXP3 into FOXP3Δ2Δ7 strongly favored Th17 differentiation in vitro.Our results demonstrate that alternative splicing of FOXP3 modulates T cell differentiation.

View Article: PubMed Central - PubMed

Affiliation: Translational Immunology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.

ABSTRACT
CD4(+)FOXP3(+) regulatory T (Treg) cells are essential for maintaining immunological self-tolerance. Treg cell development and function depend on the transcription factor FOXP3, which is present in several distinct isoforms due to alternative splicing. Despite the importance of FOXP3 in the proper maintenance of Treg cells, the regulation and functional consequences of FOXP3 isoform expression remains poorly understood. Here, we show that in human Treg cells IL-1β promotes excision of FOXP3 exon 7. FOXP3 is not only expressed by Treg cells but is also transiently expressed when naïve T cells differentiate into Th17 cells. Forced splicing of FOXP3 into FOXP3Δ2Δ7 strongly favored Th17 differentiation in vitro. We also found that patients with Crohn's disease express increased levels of FOXP3 transcripts lacking exon 7, which correlate with disease severity and IL-17 production. Our results demonstrate that alternative splicing of FOXP3 modulates T cell differentiation. These results highlight the importance of characterizing FOXP3 expression on an isoform basis and suggest that immune responses may be manipulated by modulating the expression of FOXP3 isoforms, which has broad implications for the treatment of autoimmune diseases.

No MeSH data available.


Related in: MedlinePlus

Increased alternative splicing of FOXP3 exon 7 in Crohn’s disease.(a) Schematic overview of FOXP3 depicting alternatively spliced exons, epitopes of antibody clones and binding sites for primers used for detection of each splice variant. (b) Real-time PCR quantification of FOXP3 transcripts expressing exon 2 (FOXP3ex1/2), lacking exon 2 (FOXPex1/3), and lacking exon 7 (FOXP3ex6/8) in PBMCs obtained from Crohn’s disease patients (n = 8) or healthy donors (n = 10). (c) Percentage of FOXP3ex6/8 transcripts in relation to total FOXP3 transcripts in PBMCs (n = 11) of Crohn’s disease patients and healthy donors (n = 10). (d) Crohn’s disease colon biopsies (n = 29) stratified into 50% lowest and highest FOXP3ex6/8 expression samples plotted versus clinical score. (e) Percentage of FOXP3ex6/8 transcripts in relation to total FOXP3 in intestinal biopsies obtained from Crohn’s disease patients (n = 7) before and after successful anti-TNF-α treatment. (b–e) Data represent one pooled experiment with n biological replicates and are presented as (b,d,e) mean ± SD, (c) median ± IQR. P < 0.05 was considered significant ((b,d) two-tailed unpaired Student’s t test, (c) Kruskal-Wallis ANOVA and Dunn’s post hoc test, (e) two-tailed paired Student’s t test).
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f1: Increased alternative splicing of FOXP3 exon 7 in Crohn’s disease.(a) Schematic overview of FOXP3 depicting alternatively spliced exons, epitopes of antibody clones and binding sites for primers used for detection of each splice variant. (b) Real-time PCR quantification of FOXP3 transcripts expressing exon 2 (FOXP3ex1/2), lacking exon 2 (FOXPex1/3), and lacking exon 7 (FOXP3ex6/8) in PBMCs obtained from Crohn’s disease patients (n = 8) or healthy donors (n = 10). (c) Percentage of FOXP3ex6/8 transcripts in relation to total FOXP3 transcripts in PBMCs (n = 11) of Crohn’s disease patients and healthy donors (n = 10). (d) Crohn’s disease colon biopsies (n = 29) stratified into 50% lowest and highest FOXP3ex6/8 expression samples plotted versus clinical score. (e) Percentage of FOXP3ex6/8 transcripts in relation to total FOXP3 in intestinal biopsies obtained from Crohn’s disease patients (n = 7) before and after successful anti-TNF-α treatment. (b–e) Data represent one pooled experiment with n biological replicates and are presented as (b,d,e) mean ± SD, (c) median ± IQR. P < 0.05 was considered significant ((b,d) two-tailed unpaired Student’s t test, (c) Kruskal-Wallis ANOVA and Dunn’s post hoc test, (e) two-tailed paired Student’s t test).

Mentions: The total amount of FOXP3 mRNA was 0.11 ± 0.026 arbitrary units (mean ± SEM, n = 11) in Crohn’s disease patients, which did not significantly differ (two-tailed unpaired Student’s t test) from the levels found, 0.095 ± 0.018 (mean ± SEM, n = 10), in healthy donors. We found that the absolute amount (Fig. 1b) and relative abundance of FOXP3ex6/8 mRNA (Fig. 1c), but not FOXP3ex1/2 or FOXP3ex1/3 was greater in Crohn’s disease patients than in healthy donors. This increased expression of FOXP3ex6/8 mRNA correlated with increased disease severity (Fig. 1d). Furthermore, patients with Crohn’s disease displayed slightly decreased proportions of FOXP3ex6/8 when successfully treated with anti-TNF-α antibodies (Fig. 1e).


IL-1β promotes Th17 differentiation by inducing alternative splicing of FOXP3.

Mailer RK, Joly AL, Liu S, Elias S, Tegner J, Andersson J - Sci Rep (2015)

Increased alternative splicing of FOXP3 exon 7 in Crohn’s disease.(a) Schematic overview of FOXP3 depicting alternatively spliced exons, epitopes of antibody clones and binding sites for primers used for detection of each splice variant. (b) Real-time PCR quantification of FOXP3 transcripts expressing exon 2 (FOXP3ex1/2), lacking exon 2 (FOXPex1/3), and lacking exon 7 (FOXP3ex6/8) in PBMCs obtained from Crohn’s disease patients (n = 8) or healthy donors (n = 10). (c) Percentage of FOXP3ex6/8 transcripts in relation to total FOXP3 transcripts in PBMCs (n = 11) of Crohn’s disease patients and healthy donors (n = 10). (d) Crohn’s disease colon biopsies (n = 29) stratified into 50% lowest and highest FOXP3ex6/8 expression samples plotted versus clinical score. (e) Percentage of FOXP3ex6/8 transcripts in relation to total FOXP3 in intestinal biopsies obtained from Crohn’s disease patients (n = 7) before and after successful anti-TNF-α treatment. (b–e) Data represent one pooled experiment with n biological replicates and are presented as (b,d,e) mean ± SD, (c) median ± IQR. P < 0.05 was considered significant ((b,d) two-tailed unpaired Student’s t test, (c) Kruskal-Wallis ANOVA and Dunn’s post hoc test, (e) two-tailed paired Student’s t test).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4593960&req=5

f1: Increased alternative splicing of FOXP3 exon 7 in Crohn’s disease.(a) Schematic overview of FOXP3 depicting alternatively spliced exons, epitopes of antibody clones and binding sites for primers used for detection of each splice variant. (b) Real-time PCR quantification of FOXP3 transcripts expressing exon 2 (FOXP3ex1/2), lacking exon 2 (FOXPex1/3), and lacking exon 7 (FOXP3ex6/8) in PBMCs obtained from Crohn’s disease patients (n = 8) or healthy donors (n = 10). (c) Percentage of FOXP3ex6/8 transcripts in relation to total FOXP3 transcripts in PBMCs (n = 11) of Crohn’s disease patients and healthy donors (n = 10). (d) Crohn’s disease colon biopsies (n = 29) stratified into 50% lowest and highest FOXP3ex6/8 expression samples plotted versus clinical score. (e) Percentage of FOXP3ex6/8 transcripts in relation to total FOXP3 in intestinal biopsies obtained from Crohn’s disease patients (n = 7) before and after successful anti-TNF-α treatment. (b–e) Data represent one pooled experiment with n biological replicates and are presented as (b,d,e) mean ± SD, (c) median ± IQR. P < 0.05 was considered significant ((b,d) two-tailed unpaired Student’s t test, (c) Kruskal-Wallis ANOVA and Dunn’s post hoc test, (e) two-tailed paired Student’s t test).
Mentions: The total amount of FOXP3 mRNA was 0.11 ± 0.026 arbitrary units (mean ± SEM, n = 11) in Crohn’s disease patients, which did not significantly differ (two-tailed unpaired Student’s t test) from the levels found, 0.095 ± 0.018 (mean ± SEM, n = 10), in healthy donors. We found that the absolute amount (Fig. 1b) and relative abundance of FOXP3ex6/8 mRNA (Fig. 1c), but not FOXP3ex1/2 or FOXP3ex1/3 was greater in Crohn’s disease patients than in healthy donors. This increased expression of FOXP3ex6/8 mRNA correlated with increased disease severity (Fig. 1d). Furthermore, patients with Crohn’s disease displayed slightly decreased proportions of FOXP3ex6/8 when successfully treated with anti-TNF-α antibodies (Fig. 1e).

Bottom Line: FOXP3 is not only expressed by Treg cells but is also transiently expressed when naïve T cells differentiate into Th17 cells.Forced splicing of FOXP3 into FOXP3Δ2Δ7 strongly favored Th17 differentiation in vitro.Our results demonstrate that alternative splicing of FOXP3 modulates T cell differentiation.

View Article: PubMed Central - PubMed

Affiliation: Translational Immunology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.

ABSTRACT
CD4(+)FOXP3(+) regulatory T (Treg) cells are essential for maintaining immunological self-tolerance. Treg cell development and function depend on the transcription factor FOXP3, which is present in several distinct isoforms due to alternative splicing. Despite the importance of FOXP3 in the proper maintenance of Treg cells, the regulation and functional consequences of FOXP3 isoform expression remains poorly understood. Here, we show that in human Treg cells IL-1β promotes excision of FOXP3 exon 7. FOXP3 is not only expressed by Treg cells but is also transiently expressed when naïve T cells differentiate into Th17 cells. Forced splicing of FOXP3 into FOXP3Δ2Δ7 strongly favored Th17 differentiation in vitro. We also found that patients with Crohn's disease express increased levels of FOXP3 transcripts lacking exon 7, which correlate with disease severity and IL-17 production. Our results demonstrate that alternative splicing of FOXP3 modulates T cell differentiation. These results highlight the importance of characterizing FOXP3 expression on an isoform basis and suggest that immune responses may be manipulated by modulating the expression of FOXP3 isoforms, which has broad implications for the treatment of autoimmune diseases.

No MeSH data available.


Related in: MedlinePlus