T-bet对免疫细胞分化的调节及其与自身免疫病的关系

T盒转录因子T-bet是Th1型免疫的关键调节因子,在T淋巴细胞、B淋巴细胞、树突状细胞、NK细胞效应细胞的建立和维持中发挥着极其重要的作用,一些自身免疫病,特别是典型的与Th1免疫相关的疾病,其发病需要T-bet参与,这些在动物模型中得到证实。在此,就T-het在免疫细胞分化和自身免疫病发病机制中的作用及其在干预治疗中的可行性做一综述。     

The relationship between TIGIT+ regulatory T cells and autoimmune disease

The role of regulatory T cells (Treg cell) in controlling autoimmune disease is an area of intense study. As such, the characterization and understanding the function of Treg markers has the potential to provide a considerable impact in developing treatments and understanding the pathogenesis of autoimmune diseases. One such inhibitory Treg cell marker that has been recently discovered is T cell immunoglobulin and ITIM domain (TIGIT). In this review, we discuss what is known about the expression and function of TIGIT on Treg cells, and we discuss the relationship between TIGIT expressing Treg cells and different autoimmune diseases such as atopic dermatitis, autoimmune thyroiditis, type 1 diabetes, autoimmune uveitis, aplastic anemia, multiple sclerosis, systemic lupus erythematosus, arthritis, and colitis.     

Therapeutic potential of glycolipid ligands for natural killer (NK) T cells in the suppression of autoimmune diseases

NKT cells emerge as important regulatory cells in autoimmune responses. Abnormalities in the numbers and functions of natural killer T (NKT) cells have been observed in patients with autoimmune diseases as well as in a variety of mouse strains that are genetically predisposed for development of autoimmune diseases. Unlike conventional T cells that recognize peptides in association with major histocompatibility complex (MHC), NKT cells recognize glycolipid antigens presented by the non-polymorphic MHC class I-like protein, CD1d. Recently, we and other groups have demonstrated that administration of glycolipid ligands such as alpha-galactosylceramide (alpha-GC ) or its sphingosine truncated derivative, OCH suppressed autoimmune diseases such as experimental autoimmune encephalomyelitis (EAE), diabetes in NOD mice and collagen-induced arthritis (CIA) by inducing T helper (Th) 2 bias of autoimmune T cells. OCH is a unique ligand to stimulate NKT cells to selectively produce Th2 cytokines whereas alpha-GC induces both interleukin (IL)-4 and interferon (IFN)-gamma, and is more beneficial for treatment of a wide variety of Th1-mediated autoimmune diseases. The lack of polymorphism of CD1d and cross-reactive responses of mouse and human NKT cells to the same ligand indicates that targeting NKT cells with this ligand may be an attractive means for intervening in human autoimmune diseases such as type I diabetes (T1D), multiple sclerosis (MS) and rheumatoid arthritis (RA). The present review will focus on the potential roles of NKT cells in the pathogenesis of autoimmune diseases and the recent advances in glycolipid therapy for autoimmune disease models. The molecular mechanism of OCH-induced Th2-selective cytokine secretion will also be discussed.     

Costunolide,a sesquiterpene lactone,inhibits the differentiation of pro-inflammatory CD4+ T cells through the modulation of mitogen-activated protein kinases

CD4⁺ T cell activation and adequate differentiation into effector T helper (Th) cells are crucial for mediating adaptive immune responses to cope with foreign pathogens. Despite the significant role of Th cells, excessive increases in their numbers result in inflammatory and autoimmune diseases. In this study, we investigated the effects of costunolide, a plant-derived natural compound with an anti-inflammatory activity, in regulating Th cells and the underlying mechanisms. Costunolide significantly decreased cell populations of differentiated Th1, Th2, and Th17 subsets under Th subset-polarizing conditions, while exerting statistically negligible effects on Treg cell differentiation. Furthermore, costunolide inhibited the expression level of Th subset-polarizing master genes such as T-bet, GATA3, and RORγt, indicating that costunolide inhibits the differentiation of CD4⁺ T cells into Th subsets. Additionally, costunolide suppressed the proliferative activity of CD4⁺ T cells and the expression of CD69 activation marker on CD4⁺ T cells. When the molecular targets of costunolide were investigated, phosphorylation of ERK and p38 was found to be decreased under Th subset-polarizing conditions, whereas activity of JNK remained unchanged. U0126, an ERK inhibitor, and SB203580, a p38 inhibitor, decreased the expression of CD69 upon TCR stimulation and inhibited CD4⁺ T cell differentiation, indicating that both ERK and p38 are suggested to be critical molecular targets of costunolide. Taken together, these results suggest that costunolide inhibits the differentiation of CD4⁺ T cells by suppressing ERK and p38 activities and can be an effective therapeutic agent for T cell-mediated immune diseases.     

Tet调控Th17/Treg细胞分化参与自身免疫性疾病发病的研究进展

CD4⁺ T细胞是人体免疫重要的一部分,其中辅助性T细胞17（T helper cell 17,Th17）和调节性T细胞（regulatory T cells,Treg）两个新近发现的CD4⁺ T细胞亚群在自身免疫疾病的发生发展中也起关键作用。Th17细胞能够引起自身免疫和炎性反应,而Treg细胞抑制疾病发生并维持免疫稳态;10～11易位蛋白（ten-eleven translocation,Tet）作为DNA去甲基化的关键因子,当其缺失时能够影响Th17/Treg免疫平衡。本文针对Tet调控Th17/Treg细胞分化参与自身免疫疾病发生发展的研究进展作一综述。     

Regulation of self-reactive T cells by human immunoglobulins--implications for multiple sclerosis therapy

The intravenous administration of high doses of immunoglobulins pooled from the plasma of healthy donors (IVIg therapy) has beneficial effects in patients with a variety of autoimmune disorders. These clinical observations indicate that IVIg have potent antiinflammatory characteristics, and identification of the precise mode of action may open up perspectives for future therapeutic strategies. In certain tissue-specific autoimmune disorders like multiple sclerosis (MS), self-reactive T cells recognizing autoantigens play a significant role for disease pathogenesis, as these cells are able to initiate, maintain, and propagate the harmful immune attack in experimental animal models of disease. These findings render self-reactive T cells an important therapeutic target for autoimmune diseases. Here, we review the effects of IVIg on the homeostasis of T cells and discuss the possible therapeutic implications for multiple sclerosis. As supported by several experimental studies, IVIg regulate crucial steps of T cell-mediated immune responses. These effects involve the modulation of activation, proliferation, differentiation, apoptosis, and effector mechanisms of T cells. The pattern of IVIg-T cell interactions is complex, as IVIg may directly bind to regulatory structures on T cells, or modulate T cell functions indirectly via soluble or cellular components of the immune system.     

Targeting cytokines of the interleukin-12 family in autoimmunity

In the past, autoimmunity was thought to be mediated by antibodies and immune complexes. It has now become clear that many autoimmune diseases, especially tissue specific, are T cell-mediated, or at least T cell-dependent. The pathogenesis of cell-mediated autoimmune diseases, including multiple sclerosis, uveitis, diabetes, arthritis, and others, is now thought to be, in a large measure, driven by interferon-gamma-producing, antigen-specific T cells, which are polarized toward the T helper type 1 (Th1) phenotype. Interleukin (IL)-12 and the more recently discovered IL-23 and IL-27 constitute a unique family of structurally-related, heterodimeric cytokines, which regulate cell-mediated immune responses and Th1-type inflammatory reactions. Thus, these cytokines may have a central role in the development and progression of cell-mediated autoimmune diseases. Therefore, pharmacologically targeting cytokines of the IL-12 family would be useful in the modulation of several autoimmune diseases. This review summarizes the recent findings concerning IL-12 family cytokine-mediated autoreactive inflammatory responses, and also describes some possible therapeutic interventions, including medicinal compounds at mitigating autoimmune inflammation.     

Estrogen, a double-edged sword: modulation of TH1- and TH2-mediated inflammations by differential regulation of TH1/TH2 cytokine production

Estrogen appears to play a central role in the immune response and immune-mediated diseases. Estrogen receptors are expressed in a variety of immunocompetent cells, including CD4(+) and CD8(+) T cells and macrophages. Clinical observations indicate that some autoimmune diseases, such as rheumatoid arthritis and multiple sclerosis, frequently remit during pregnancy but exacerbate, or have their onset during the postpartum period. Pharmacological levels of estrogen also appear to ameliorate certain autoimmune diseases. In addition, estrogen is known to suppress certain infectious diseases, as well as T cell-mediated responses toward oxazolone, keyhol lympet hemocyanin, Listeria soluble protein and purified protein derivatives. The immune basis for these phenomena is poorly understood. Based on a distinctive profile of cytokine production, data accumulated thus far have revealed modulatory effects for estrogen on the TH1-type and TH2-type cells, which represent two polarized forms of the effector specific immune response. Recent evidence indicates that estrogens inhibit the production of TH1 proinflammatory cytokines, such as IL-12, TNF-alpha and IFN-gamma, whereas they stimulate the production of TH2 anti-inflammatory cytokines, such as IL-10, IL-4, and TGF-beta. This can explain why estrogen suppresses and potentiates TH1- and TH2-mediated diseases, respectively. We hypothesize that exacerbation or suppression of inflammatory diseases by estrogen is mediated by skewing TH1-type to TH2-type response. This view represents a novel mechanism for the modulatory effect of estrogen on certain inflammatory diseases that can lead to beneficial or detrimental impacts depending on the type of immune involved. Such a concept is valuable when considering the application of combination therapies that include estrogen.     

Therapeutic benefits of regulating inflammation in autoimmunity

Autoimmunity results from the dysregulation of the immune system leading to tissue damage. Th1 and Th17 cells are known to be cellular mediators of inflammation in autoimmune diseases. The specific cytokine milieu within the site of inflammation or within secondary lymphatic tissues is important during the priming and effector phases of T cell response. In this review, we will address the nature of the inflammatory response in the context of autoimmune disease, specifically we will discuss the role of dendritic cells following stimulation of their innate pathogen recognition receptors in directing the development of T cell responses. We will focus on how dendritic cell subsets change the balance between major players in autoimmunity, namely Th1, Th17 and regulatory T cells. Th17 cells, once thought to only act as pathogenic effectors through production of IL-17, have been shown to have regulatory properties as well with co-production of the anti-inflammatory cytokine IL-10 by a subset now referred to as regulatory Th17 cells. IL-17 is important in the induction of autoimmune diseases such as experimental autoimmune encephalomyelitis (EAE) and inflammatory bowel disease (IBD). Study of the inflammatory process following encounter with agents that stimulate the innate immune responses such as adjuvants opens a new horizon for the discovery of therapeutic agents including those derived from microorganisms. Microbial products such as adjuvants that function as TLR ligands may stimulate the immune system by interacting with Toll-like receptors (TLR) on antigen-presenting cells. Microbial agents such as Bacille Calmette-Guérin (BCG) or Freund's adjuvant (CFA) that induce a Th17 response are protective in models of autoimmune diseases particularly EAE and type 1 diabetes (T1D). The induction of innate immunity by these microbial products alters the balance in the cytokine microenvironment and may be responsible for modulation of the inflammation and protection from autoimmunity.     

S-nitrosoglutathione a Physiologic Nitric Oxide Carrier Attenuates Experimental Autoimmune Encephalomyelitis

S-nitrosoglutathione (GSNO) is a physiological nitric oxide molecule which regulates biological activities of target proteins via s-nitrosylation leading to attenuation of chronic inflammation. In this study we evaluated the therapeutic efficacy of GSNO in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Oral administration of GSNO (0.5 or 1.0 mg/kg) reduced disease progression in chronic models (SJL and C57BL/6) of EAE induced with PLP_(139–151) or MOG_(35–55) peptides, respectively. GSNO attenuated EAE disease by reducing the production of IL17 (from Th_i or Th17 cells) and the infiltration of CD4 T cells into the central nervous system without affecting the levels of Th1 (IFNγ) and Th2 (IL4) immune responses. Inhibition of IL17 was observed in T cells under normal as well as Th17 skewed conditions. In vitro studies showed that the phosphorylation of STAT3 and expression of RORγ, key regulators of IL17 signaling, were reduced while phosphorylation of STAT4 or STAT6 and expression of T-bet or GATA3 remained unaffected, suggesting that GSNO preferentially targets Th17 cells. Collectively, GSNO attenuated EAE via modulation of Th17 cells and its effects are independent of Th1 or Th2 cells functions, indicating that it may have therapeutic potential for Th17-mediated autoimmune diseases.     

The role of infections in the pathogenesis of autoimmune diseases

The autoimmune diseases result from inappropriate responses of the immune system to self antigens. The etiology of autoimmune diseases remains largely unknown but candidate etiologic factors include genetic abnormalities and infections. Although there are considerable data supporting the role of infections in a variety of autoimmune diseases, this role has been unequivocally established in only a few autoimmune diseases. The difficulty in establishing the infectious etiology of autoimmune diseases stems from several factors such as the heterogeneity of clinical manifestations in individual autoimmune diseases and the time interval between infection and autoimmune disease. The data on this association derive from clinical observations, epidemiological studies and research using laboratory techniques, protein sequence database screening and animal models. Infectious agents can cause autoimmune diseases by different mechanisms, which fall into two categories: antigen specific in which pathogen products or elements have a central role e.g. superantigens or epitope (molecular) mimicry, and antigen non-specific in which the pathogen provides the appropriate inflammatory setting for "bystander activation". The most important mechanisms are molecular mimicry and superantigens. As far as molecular mimicry is concerned the recent data on the degeneracy of T cell recognition shifted the focus from searching for linear sequence homology to looking for similarity of antigenic surfaces. Special mention has to be made to retroviruses as they have some unique means of inducing autoimmunity.     

CD160/HVEM/BTLA/LIGHT通路在自身免疫病中的研究进展

共信号分子是免疫细胞表面信号传递分子及其配体，对调控T细胞或B细胞的活化有重要作用。近年来，研究显示多种共信号分子对T细胞的激活与免疫平衡有重要调控作用，这些分子的异常表达可以引起T细胞的过度激活并引发自身免疫病。CD160/HVEM/BTLA/LIGHT通路是近年来共信号分子领域的研究热点，该信号通路在免疫调节中起重要的作用，其功能异常或异常表达与自身免疫病的发生密切相关。本文对该通路在自身免疫病中的研究进展做一简要综述。     

Th17 cells in inflammation

Na?ve T cells are multipotential precursors that differentiate into various effector subsets, such as T helper type 1 (Th1) and Th2 cells, which are characterized by their distinct functions. The IL-17-producing T helper (Th17) cell has been recently identified as a new subset of the T helper cell and a mediator of inflammation associated with various autoimmune diseases. Although several cytokines participate in Th17 cell development, IL-6 and TGF-β are key factors for the generation of Th17 cells from na?ve T cells. On the other hand, IL-6 inhibits TGF-β-induced regulatory T (Treg) cells, which suppress adaptive T cell responses and prevent autoimmunity. Recent studies suggest that it is an effective approach in the treatment of various autoimmune and inflammatory diseases to normalize the balance between Treg and Th17 cell development. Here, we review the discovery of the Th17 subset, its properties and relationship with several autoimmune diseases.     

Regulatory T cells for immunotherapy of autoimmune diseases: from the bench to the bedside

The induction of antigen-specific unresponsiveness or tolerance is critical for the prevention of autoimmunity and maintenance of immune homeostasis. The presence of regulatory T cells (Treg cells) has been recently demonstrated in animals and in humans. Interestingly, Treg cells may be either quantitatively or qualitatively altered in human autoimmune diseases, for example, multiple sclerosis, psoriasis, Type 1 diabetes and inflammatory bowel disease (IBD), suggesting a role in disease pathophysiology. The present review summarises the emerging literature on the developmental origin and function of human Treg cells. The potential clinical application of Treg cells to human autoimmune diseases and to post-transplantation graft-versus-host disease is discussed.