Project description:Foxp3 expressing regulatory T cells (Tregs) are the central regulator of immune homeostasis and tolerance. As it is believed that proper Treg function is compromised under inflammatory conditions, exploring a pathway that enhances Treg function is of great importance. In this study, we report that IL-27, an IL-12 family cytokine known to play both pro- and anti-inflammatory role in T cells, plays a pivotal role in Treg function to control T cell-induced colitis. Unlike WT Tregs capable of inhibiting colitogenic T cell expansion and inflammatory cytokine expression, IL-27R-deficient Tregs were unable to downregulate inflammatory T cell responses. Tregs stimulated with IL-27 expressed substantially enhanced suppressive function both in vitro and in vivo. IL-27 stimulation of Tregs induced expression of LAG3, a surface molecule implicated in negatively regulating immune responses. LAG3 expression in IL-27-stimulated Tregs was critical to mediate suppressive Treg function. Finally, human Tregs also displayed enhanced suppressive function and LAG3 expression in response to IL-27 stimulation. Taken together, our results highlight a novel function of the IL-27/LAG3 axis in Treg regulation of inflammatory responses in the intestine. FACS purified Foxp3+ Tregs were stimulated in the presence of media or IL-27 to compare IL-27 induced gene profiles. Four samples (media stimulated or IL-27-stimulated) were collected from four independent experiments. Genes altered by IL-27 treatment were compared to those of media stimulated Tregs.
Project description:The objective of this study was to determine if a subset of regulatory T cells (Tregs) expressing the transcription factor, Zbtb20, played a unique role in the function of the immune system. Genetic reporter mice were used to isolate Zbtb20-expressing Tregs as well as activated (CD62Llo) and naive (CD62Lhi) Tregs. The gene expression in these cells was determined with RNA-seq.
Project description:Interleukin-17 (IL-17) family cytokines promote protective inflammation for pathogen resistance, but also facilitate autoimmunity and tumor development. A direct signal of IL-17 to regulatory T cells (Tregs) has not been reported and may help explain these dichotomous responses. Here we show in mice that IL-17 Receptor A (IL-17RA) is expressed in Tregs that reside in mouse mesenteric lymph nodes and colon tumors, as well as in patients with colorectal cancer (CRC). Ablation of IL-17RA, specifically in Tregs, resulted in increased Th17 cells, and exacerbated tumor development. Mechanistically, tumor-infiltrating Tregs exhibit a unique gene signature that is linked to their activation, maturation, and suppression function, and this signature is in part supported by the direct signaling of IL-17 to Tregs. To study pathways of Treg programming, we found that loss of IL-17RA in tumor Tregs resulted in reduced RNA splicing, and downregulation of several RNA binding proteins that are known to regulate alternative splicing and promote Treg function. Taken together, we report a direct role of IL-17 in promoting Treg maturation and function in CRC.
Project description:In psoriasis lesions, a diverse mixture of cytokines is upregulated which influence each other generating a complex inflammatory situation. Although this is the case, the inhibition of Interleukin-17A (IL-17A) alone showed unprecedented clinical results in patients, indicating that IL-17A is a critical inducer of psoriasis pathogenesis. To elucidate IL-17A-driven keratinocyte-intrinsic signaling pathways, we treated monolayers of normal human epidermal keratinocytes in vitro with a mixture of 6 cytokines (IL-17A, TNF-a, IL-17C, IL-22, IL-36g and IFN-g) involved in psoriasis, to mimic the inflammatory milieu in psoriasis lesions. Microarray and gene set enrichment analysis revealed that this cytokine mixture induced similar gene expression changes with the previous transcriptome studies using psoriasis lesions. Importantly, we identified a set of IL-17A-regulated genes in keratinocytes, which recapitulate typical psoriasis genes exemplified by DEFB4A, S100A7, IL19 and CSF3, based on differences in the expression profiles of cells stimulated with 6 cytokines versus cells stimulated with only 5 cytokines lacking IL-17A. Furthermore a specific IL-17A-induced gene, NFKBIZ, which encodes IkappaB-zeta, a transcriptional regulator for NF-kappaB, was demonstrated to have a significant role for IL-17A-induced gene expression. Thus, we present novel in vitro data from normal human keratinocytes that would help elucidating the IL-17A-driven keratinocyte activation in psoriasis. Cytokine mixture-induced gene expression in primary normal human epidermal keratinocytes (NHEKs) was measured at 24 hours after exposure. NHEKs were exposed to the combination of selected six cytokines (IL-17A: 100 ng/ml, TNF-a: 10 ng/ml, IFN-g: 10 ng/ml, IL-17C: 100 ng/ml, IL-22: 100 ng/ml, IL-36g: 500 ng/ml) , or to the different combinations of five of the six cytokines (in total, 7 different treatments and one untreated control). No replicate experiments were conducted.
Project description:Bleomycin (BLM) induces lung injury, leading to inflammation and pulmonary fibrosis. Regulatory T cells (Tregs) maintain self-tolerance and control host immune responses. However, little is known about their involvement in the pathology of pulmonary fibrosis. Here we show that a unique Treg subset that expresses trefoil factor family 1(Tff1) emerges in the BLM-injured lung. These Tff1-expressing Tregs (Tff1-Tregs) were induced by IL-33. Moreover, although Tff1 ablation in Tregs had no impact, selective ablation of Tff1-Tregs using an intersectional genetic method promoted pro-inflammatory features of macrophages in the injured lung and exacerbated the fibrosis. Taken together, our study revealed the presence of a unique Treg subset expressing Tff1 in BLM-injured lungs and their critical role in the injured lung to ameliorate fibrosis.
Project description:Foxp3 expressing regulatory T cells (Tregs) are the central regulator of immune homeostasis and tolerance. As it is believed that proper Treg function is compromised under inflammatory conditions, exploring a pathway that enhances Treg function is of great importance. In this study, we report that IL-27, an IL-12 family cytokine known to play both pro- and anti-inflammatory role in T cells, plays a pivotal role in Treg function to control T cell-induced colitis. Unlike WT Tregs capable of inhibiting colitogenic T cell expansion and inflammatory cytokine expression, IL-27R-deficient Tregs were unable to downregulate inflammatory T cell responses. Tregs stimulated with IL-27 expressed substantially enhanced suppressive function both in vitro and in vivo. IL-27 stimulation of Tregs induced expression of LAG3, a surface molecule implicated in negatively regulating immune responses. LAG3 expression in IL-27-stimulated Tregs was critical to mediate suppressive Treg function. Finally, human Tregs also displayed enhanced suppressive function and LAG3 expression in response to IL-27 stimulation. Taken together, our results highlight a novel function of the IL-27/LAG3 axis in Treg regulation of inflammatory responses in the intestine.
Project description:Interleukin-17 (IL-17) family cytokines promote protective inflammation for pathogen resistance, but also facilitate autoimmunity and tumor development. A direct signal of IL-17 to regulatory T cells (Tregs) has not been reported and may help explain these dichotomous responses. Here we show in mice that IL-17 Receptor A (IL-17RA) is expressed in Tregs that reside in mouse mesenteric lymph nodes and colon tumors, as well as in patients with colorectal cancer (CRC). Ablation of IL-17RA, specifically in Tregs, resulted in increased Th17 cells, and exacerbated tumor development. Mechanistically, tumor-infiltrating Tregs exhibit a unique gene signature that is linked to their activation, maturation, and suppression function, and this signature is in part supported by the direct signaling of IL-17 to Tregs. To study pathways of Treg programming, we found that loss of IL-17RA in tumor Tregs resulted in reduced RNA splicing, and downregulation of several RNA binding proteins that are known to regulate alternative splicing and promote Treg function. Taken together, we report a direct role of IL-17 in promoting Treg maturation and function in CRC.