Th9 cells: differentiation and disease.
TL;DR: This review focuses on recent developments in understanding the signals that promote Th9 differentiation, the transcription factors that regulate IL‐9 expression, and finally the potential roles for Th9 cells in immunity in vivo.
Abstract: CD4+ T-helper cells regulate immunity and inflammation through the acquisition of potential to secrete specific cytokines. The acquisition of cytokine-secreting potential, in a process termed T-helper cell differentiation, is a response to multiple environmental signals including the cytokine milieu. The most recently defined subset of T-helper cells are termed Th9 and are identified by the potent production of interleukin-9 (IL-9). Given the pleiotropic functions of IL-9, Th9 cells might be involved in pathogen immunity and immune-mediated disease. In this review, I focus on recent developments in understanding the signals that promote Th9 differentiation, the transcription factors that regulate IL-9 expression, and finally the potential roles for Th9 cells in immunity in vivo.
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TL;DR: This review systemically reviewed the pathogenesis of IBD and highlighted recent advances in host genetic factors, gut microbiota, and environmental factors and, especially, in abnormal innate and adaptive immune responses and their interactions, which may hold the keys to identify novel predictive or prognostic biomarkers and develop new therapies.
Abstract: Inflammatory bowel disease (IBD) is a chronic and life-threating inflammatory disease of gastroenteric tissue characterized by episodes of intestinal inflammation. The pathogenesis of IBD is complex. Recent studies have greatly improved our knowledge of the pathophysiology of IBD, leading to great advances in the treatment as well as diagnosis of IBD. In this review, we have systemically reviewed the pathogenesis of IBD and highlighted recent advances in host genetic factors, gut microbiota, and environmental factors and, especially, in abnormal innate and adaptive immune responses and their interactions, which may hold the keys to identify novel predictive or prognostic biomarkers and develop new therapies.
374 citations
Cites background from "Th9 cells: differentiation and dise..."
...1/Smad/Stat6 for Th9, RORγt/Stat3 for Th17, and Foxp3/Stat5 for iTreg [148, 149]....
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...In the presence of IL-4 and TGF-β, naïve CD4 T cells may differentiate into Th9 cells secreting IL-9, IL-10, and IL-21, which regulate allergic inflammation, autoimmune inflammation, and antitumor immunity [149]....
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TL;DR: This review focuses mainly on the developmental and functional mechanisms of the human neonatal immune system and the mechanism of innate and adaptive immunity and the role of neutrophils, antigen presenting cells, differences in subclasses of T lymphocytes (Th1, Th2, Tregs and B cells are discussed.
Abstract: Neonates have little immunological memory and a developing immune system, which increases their vulnerability to infectious agents. Recent advances in the understanding of neonatal immunity indicate that both innate and adaptive responses are dependent on precursor frequency of lymphocytes, antigenic dose and mode of exposure. Studies in neonatal mouse models and human umbilical cord blood cells demonstrate the capability of neonatal immune cells to produce immune responses similar to adults in some aspects but not others. This review focuses mainly on the developmental and functional mechanisms of the human neonatal immune system. In particular, the mechanism of innate and adaptive immunity and the role of neutrophils, antigen presenting cells, differences in subclasses of T lymphocytes (Th1, Th2, Tregs) and B cells are discussed. In addition, we have included the recent developments in the neonatal mouse immune system. Understanding neonatal immunity is essential to development of therapeutic vaccines to combat newly emerging infectious agents.
346 citations
Cites background from "Th9 cells: differentiation and dise..."
...A new subset of T helper cells, Th9, produces IL-9 found in the peripheral blood of allergic patients [114]....
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TL;DR: The findings suggest that the TH9 subset of helper T cells serves an important role in driving ulcerative colitis by regulating intestinal epithelial cells and that TH9 cells represent a likely target for the treatment of chronic intestinal inflammation.
Abstract: The molecular checkpoints that drive inflammatory bowel diseases are incompletely understood. Here we found more T cells expressing the transcription factor PU.1 and interleukin 9 (IL-9) in patients with ulcerative colitis. In an animal model, citrine reporter mice had more IL-9-expressing mucosal T cells in experimental oxazolone-induced colitis. IL-9 deficiency suppressed acute and chronic colitis. Mice with PU.1 deficiency in T cells were protected from colitis, whereas treatment with antibody to IL-9 suppressed colitis. Functionally, IL-9 impaired intestinal barrier function and prevented mucosal wound healing in vivo. Thus, our findings suggest that the TH9 subset of helper T cells serves an important role in driving ulcerative colitis by regulating intestinal epithelial cells and that TH9 cells represent a likely target for the treatment of chronic intestinal inflammation.
317 citations
TL;DR: This Review focuses on the extracellular signals and the transcription factors that promote the development of what is now term TH9 cells, which are characterized by the production of this cytokine.
Abstract: This Review summarizes our current understanding of the key factors that regulate the differentiation of T helper 9 (TH9) cells. The authors discuss how TH9 cells can contribute to protective immunity to infection but may also drive immunopathology in diseases such as allergic asthma and inflammatory bowel disease.
299 citations
TL;DR: The latest advances in the understanding of the role of Tcell subsets in atherosclerosis are described, the process of T cell homing to atherosclerotic plaques is discussed, and potential T cell-related therapies for atheros sclerosis are highlighted.
Abstract: Atherosclerosis is a chronic inflammatory disease of the arterial wall and the primary underlying cause of cardiovascular disease. Data from in vivo imaging, cell-lineage tracing and knockout studies in mice, as well as clinical interventional studies and advanced mRNA sequencing techniques, have drawn attention to the role of T cells as critical drivers and modifiers of the pathogenesis of atherosclerosis. CD4+ T cells are commonly found in atherosclerotic plaques. A large body of evidence indicates that T helper 1 (TH1) cells have pro-atherogenic roles and regulatory T (Treg) cells have anti-atherogenic roles. However, Treg cells can become pro-atherogenic. The roles in atherosclerosis of other TH cell subsets such as TH2, TH9, TH17, TH22, follicular helper T cells and CD28null T cells, as well as other T cell subsets including CD8+ T cells and γδ T cells, are less well understood. Moreover, some T cells seem to have both pro-atherogenic and anti-atherogenic functions. In this Review, we summarize the knowledge on T cell subsets, their functions in atherosclerosis and the process of T cell homing to atherosclerotic plaques. Much of our understanding of the roles of T cells in atherosclerosis is based on findings from experimental models. Translating these findings into human disease is challenging but much needed. T cells and their specific cytokines are attractive targets for developing new preventive and therapeutic approaches including potential T cell-related therapies for atherosclerosis. Accumulating evidence supports the critical role of T cells as drivers and modifiers of atherosclerosis. In this Review, Ley and colleagues describe the latest advances in our understanding of the role of T cell subsets in atherosclerosis, discuss the process of T cell homing to atherosclerotic plaques and highlight potential T cell-related therapies for atherosclerosis.
297 citations
References
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TL;DR: It is shown that the perceived central role for IL-12 in autoimmune inflammation, specifically in the brain, has been misinterpreted and that IL-23, and not IL- 12, is the critical factor in this response.
Abstract: Interleukin-12 (IL-12) is a heterodimeric molecule composed of p35 and p40 subunits. Analyses in vitro have defined IL-12 as an important factor for the differentiation of naive T cells into T-helper type 1 CD4+ lymphocytes secreting interferon-gamma (refs 1, 2). Similarly, numerous studies have concluded that IL-12 is essential for T-cell-dependent immune and inflammatory responses in vivo, primarily through the use of IL-12 p40 gene-targeted mice and neutralizing antibodies against p40. The cytokine IL-23, which comprises the p40 subunit of IL-12 but a different p19 subunit, is produced predominantly by macrophages and dendritic cells, and shows activity on memory T cells. Evidence from studies of IL-23 receptor expression and IL-23 overexpression in transgenic mice suggest, however, that IL-23 may also affect macrophage function directly. Here we show, by using gene-targeted mice lacking only IL-23 and cytokine replacement studies, that the perceived central role for IL-12 in autoimmune inflammation, specifically in the brain, has been misinterpreted and that IL-23, and not IL-12, is the critical factor in this response. In addition, we show that IL-23, unlike IL-12, acts more broadly as an end-stage effector cytokine through direct actions on macrophages.
2,915 citations
TL;DR: Cellular and molecular mechanisms in the differentiation and function of regulatory T cells and their role in autoimmune and autoinflammatory disorders, allergy, acute and chronic infections, cancer, and metabolic inflammation are discussed.
Abstract: The immune system has evolved to mount an effective defense against pathogens and to minimize deleterious immune-mediated inflammation caused by commensal microorganisms, immune responses against self and environmental antigens, and metabolic inflammatory disorders. Regulatory T (Treg) cell–mediated suppression serves as a vital mechanism of negative regulation of immune-mediated inflammation and features prominently in autoimmune and autoinflammatory disorders, allergy, acute and chronic infections, cancer, and metabolic inflammation. The discovery that Foxp3 is the transcription factor that specifies the Treg cell lineage facilitated recent progress in understanding the biology of regulatory T cells. In this review, we discuss cellular and molecular mechanisms in the differentiation and function of these cells.
2,356 citations
TL;DR: The results suggest that TH17 cells, through the production of both IL-22 and IL-17, might have essential functions in host defence and in the pathogenesis of autoimmune diseases such as psoriasis.
Abstract: Psoriasis is a chronic inflammatory skin disease characterized by hyperplasia of the epidermis (acanthosis), infiltration of leukocytes into both the dermis and epidermis, and dilation and growth of blood vessels. The underlying cause of the epidermal acanthosis in psoriasis is still largely unknown. Recently, interleukin (IL)-23, a cytokine involved in the development of IL-17-producing T helper cells (T(H)17 cells), was found to have a potential function in the pathogenesis of psoriasis. Here we show that IL-22 is preferentially produced by T(H)17 cells and mediates the acanthosis induced by IL-23. We found that IL-23 or IL-6 can directly induce the production of IL-22 from both murine and human naive T cells. However, the production of IL-22 and IL-17 from T(H)17 cells is differentially regulated. Transforming growth factor-beta, although crucial for IL-17 production, actually inhibits IL-22 production. Furthermore, IL-22 mediates IL-23-induced acanthosis and dermal inflammation through the activation of Stat3 (signal transduction and activators of transcription 3) in vivo. Our results suggest that T(H)17 cells, through the production of both IL-22 and IL-17, might have essential functions in host defence and in the pathogenesis of autoimmune diseases such as psoriasis. IL-22, as an effector cytokine produced by T cells, mediates the crosstalk between the immune system and epithelial cells.
1,825 citations
TL;DR: These findings suggest that full acquisition of pathogenic function by effector TH-17 cells is mediated by IL-23 rather than by TGF-β and IL-6, which 'drive' initial lineage commitment but also 'restrain' the pathogenic potential of TH- 17 cells.
Abstract: Studies have shown that transforming growth factor-beta (TGF-beta) and interleukin 6 (IL-6) are required for the lineage commitment of pathogenic IL-17-producing T helper cells (T(H)-17 cells). Unexpectedly, here we found that stimulation of myelin-reactive T cells with TGF-beta plus IL-6 completely abrogated their pathogenic function despite upregulation of IL-17 production. Cells stimulated with TGF-beta plus IL-6 were present in the spleen as well as the central nervous system, but they failed to upregulate the proinflammatory chemokines crucial for central nervous system inflammation. In addition, these cells produced IL-10, which has potent anti-inflammatory activities. In contrast, stimulation with IL-23 promoted expression of IL-17 and proinflammatory chemokines but not IL-10. Hence, TGF-beta and IL-6 'drive' initial lineage commitment but also 'restrain' the pathogenic potential of T(H)-17 cells. Our findings suggest that full acquisition of pathogenic function by effector T(H)-17 cells is mediated by IL-23 rather than by TGF-beta and IL-6.
1,458 citations
TL;DR: It is shown that transforming growth factor-β constitutes a regulatory 'switch' that in combination with other cytokines can 'reprogram' effector T cell differentiation along different pathways.
Abstract: Since the discovery of T helper type 1 and type 2 effector T cell subsets 20 years ago, inducible regulatory T cells and interleukin 17 (IL-17)-producing T helper cells have been added to the 'portfolio' of helper T cells. It is unclear how many more effector T cell subsets there may be and to what degree their characteristics are fixed or flexible. Here we show that transforming growth factor-beta, a cytokine at the center of the differentiation of IL-17-producing T helper cells and inducible regulatory T cells, 'reprograms' T helper type 2 cells to lose their characteristic profile and switch to IL-9 secretion or, in combination with IL-4, drives the differentiation of 'T(H)-9' cells directly. Thus, transforming growth factor-beta constitutes a regulatory 'switch' that in combination with other cytokines can 'reprogram' effector T cell differentiation along different pathways.
1,164 citations
"Th9 cells: differentiation and dise..." refers background in this paper
...IL4, its receptor, STAT6, and GATA3 are required for both Th2 and Th9 cell development (2, 4, 10)....
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...Not surprisingly, considering the importance of IL-4 in the development of Th9 cells, STAT6 is absolutely required for IL-9 production (2, 4, 10)....
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...Initial reports utilized mice expressing a dominant negative TGFbRII transgene in CD4 T cells to demonstrate that Th9 cells are required for immunity to Trichuris muris (4)....
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...TGFb can convert Th2 cells to IL-9secreting cells (4)....
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