Evaluation of the expression of T helper lymphocytes markers associated with Th1, Th2, Th17, and Treg cells in primary pterygium biopsies
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Introduction: Various pro-inflammatory cytokines and growth factors have been implicated in the pathogenesis of pterygium (Pt); however, the effect of cytokines produced by helper T lymphocytes (Th) has been poorly studied. To date, only interleukin 4 (IL-4) from Th lymphocytes has been linked to Pt recurrence. Therefore, this study aimed to evaluate the expression of Th cytokines and Th transcription factors in primary Pt. Methods: Pt biopsies were obtained from 28 eyes of 28 Mexican patients undergoing primary excision of Pt with conjunctival autograft. Conjunctival biopsies of 8 patients undergoing cataract surgery were used as the control group. Gene expression of Th cytokines - interferon gamma (IFN-γ), IL-13, IL-17, IL-10-, as well as gene expression of Th transcription factors T-bet, GATA3, Foxp3 and RORγt, was analyzed by real-time RT-PCR. results: We found decreased expression of markers T-bet, GATA3, RORγt, IFN- γ, IL-13 and IL-10 in Pt. We found a sixfold increase in the expression of IL-17 and Foxp3 in Pt compared to healthy conjunctiva (p < 0.0001); this increase was dependent on Pt size. Conclusions: The increased expression of IL-17 and Foxp3 in Pt samples suggests the presence of IL-17+ Foxp3⁺ Th lymphocytes, a subset of the Th population with the ability to suppress T cell proliferation and promote tumor progression. Therefore, IL17⁺ Foxp3⁺ Th cells may be involved in the occurrence and growth of Pt.
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A new method of total RNA isolation by a single extraction with an acid guanidinium thiocyanate-phenol-chloroform mixture is described. The method provides a pure preparation of undegraded RNA in high yield and can be completed within 4 h. It is particularly useful for processing large numbers of samples and for isolation of RNA from minute quantities of cells or tissue samples.
The exact pathogenesis of pterygium has not been completely elucidated. Growth factors have been considered to play a role in pterygium formation. Vascular endothelial growth factor (VEGF) is one of the principal mediators of angiogenesis, fibroblast stimulation and tissue remodeling in allergic conditions. The aim of this study was to compare the association between pterygium and VEGF gene expression between atopic and non-atopic individuals. At first visit, all patients with pterygium underwent blood tests, serum immunoglobulin E (IgE), serum cytokines including interleukin-4 (IL-4) and interferon-γ (IFN-γ) and peripheral blood eosinophil count. After obtaining informed consents, questionnaires were used to obtain demographic and clinical data from patients who underwent pterygium excision surgery. Skin prick test was performed to confirm or rule out atopy in 30 patients with (case group) and 30 patients without (control group) atopy. Pterygium tissues were then removed by surgery. A semi-quantitative reverse transcriptase polymerase chain reaction was performed to determine VEGF gene expression in all patients. Our results illustrated that VEGF mRNA expression in atopic patients was significantly higher than in the non-atopic group (P = 0.01). Eosinophil count, serum IgE and IL-4 were also significantly higher in atopic patients than in the non-atopic group (P = 0.03, 0.001 and 0.001, respectively). However, no significant difference was noted in serum IFN-γ between the two groups (P = 0.06). The excessive expression of VEGF gene in pterygium tissue of patients with atopy suggests that growth factors may play a role in the pathogenesis of pterygium or accelerate its formation.
Dry eye is an inflammatory disease that results from activation of innate inflammatory pathways in resident ocular surface cells, as well as cytokines produced by recruited T helper (Th) cells. Cytokines produced by the infiltrating Th cells alter the normal cytokine balance on the ocular surface and cause ocular surface epithelial pathology. Changes in levels of Th cytokines on the ocular surface have been measured in dry eye and the biological effects of these cytokines have been documented in experimental culture and mouse model systems. The Th2 cytokine IL-13 has a homeostatic role in promoting goblet cell differentiation. In contrast, The Th1 cytokine IFN-γ antagonizes IL-13 and promotes apoptosis and squamous metaplasia of the ocular surface epithelia. The Th17 cytokine, IL-17 promotes corneal epithelial barrier disruption. The ocular surface epithelium expresses receptors to all of these Th cytokines. Therapies that maintain normal IL-13 signaling, or suppress IFN- γ and IL-17 have potential for treating the ocular surface disease of dry eye.
CD4+ T cells play central roles to appropriate protection against pathogens. While, they can also be pathogenic driving inflammatory diseases. Besides the classical model of differentiation of T helper 1 (Th1) and Th2 cells, various CD4+ T cell subsets, including Th17, Th9, T follicular helper (Tfh) and T regulatory (Treg) cells, have been recognized recently. In this review, we will focus on how these various CD4+ T cell subsets contribute to the pathogenesis of immune-mediated inflammatory diseases. We will also discuss various unique subpopulations of T helper cells that have been identified. Recent advancement of the basic immunological research revealed that T helper cells are plastic than we imagined. So, we will focus on the molecular mechanisms underlying the generation of the plasticity and heterogeneity of T helper cell subsets. These latest finding regarding T helper cell subsets has pushed us to reconsider the etiology of immune-mediated inflammatory diseases beyond the model based on the conventional Th1/Th2 balance. Toward this end, we put forward another model, “the pathogenic Th population disease induction model”, as a possible mechanism for the induction and/or persistence of immune-mediated inflammatory diseases.
CD4+ T cells are crucial for directing appropriate immune responses during host defense and for the pathogenesis of inflammatory
diseases. In addition to the classical biphasic model of differentiation of T-helper 1 (Th1) and Th2 cells, unexpected increases in the numbers of CD4+ T cell subsets, including Th17, Th9, T follicular-helper (Tfh) and T-regulatory (Treg) cells, have been recognized. In the present review, we focus on how these various T-helper cell subsets contribute to the
pathogenesis of immune-mediated inflammatory diseases. In particular, we focus on multiple sclerosis, psoriasis and asthma
as typical model diseases in which multiple T-helper cell subsets have recently been suggested to play a role. We will also
discuss various unique subpopulations of T-helper cells that have been identified. First, we will introduce the heterogeneous
T-helper cell subsets, which are classified by their simultaneous expression of multiple key transcription factors. We will
also introduce different kinds of memory-type Th2 cells, which are involved in the pathogenesis of chronic type-2 immune related diseases. Finally, we will discuss the molecular
mechanisms underlying the generation of the plasticity and heterogeneity of T-helper cell subsets. The latest progress in
the study of T-helper cell subsets has forced us to reconsider the etiology of immune-mediated inflammatory diseases beyond
the model based on the Th1/Th2 balance. To this end, we propose another model — the pathogenic T-helper population disease-induction model — as a possible
mechanism for the induction and/or persistence of immune-mediated inflammatory diseases.
Foxp3(+) Tregs have been known as a major regulator of immune homeostasis through their immunosuppressive function. Th17 lineage is a CD4(+) T cell subset that exerts its function by secreting proinflammatory cytokines and protecting host against microbial infections. The altered ratio between Foxp3(+) Tregs and Th17 cells plays an important role in the pathogenesis of immune-related diseases. Recent mice and human studies have demonstrated that Tregs can be reprogrammed into a novel population, IL-17(+)Foxp3(+) T cells, phenotypically and functionally resembling Th17 cells under the complicated cytokine stimulation. The identification of IL-17(+)Foxp3(+) T cells may provide a new understanding of therapy targeting Tregs and Th17 cells in autoimmune diseases and cancer. Here, we highlight significant data regarding the phenotype profile, origination, differentiation, and the pleiotropic functions of IL-17(+)Foxp3(+) T cells and the reciprocal relationships of these cells to Tregs and Th17 cells. Furthermore, the role of IL-17(+)Foxp3(+) T cells in tumorigenesis and clinical implications in cancer therapy are discussed in this review.
Autoimmune diseases often result from an imbalance between regulatory T (Treg) cells and interleukin-17 (IL-17)-producing T helper (TH17) cells; the origin of the latter cells remains largely unknown. Foxp3 is indispensable for the suppressive function of Treg cells, but the stability of Foxp3 has been under debate. Here we show that TH17 cells originating from Foxp3(+) T cells have a key role in the pathogenesis of autoimmune arthritis. Under arthritic conditions, CD25(lo)Foxp3(+)CD4(+) T cells lose Foxp3 expression (herein called exFoxp3 cells) and undergo transdifferentiation into TH17 cells. Fate mapping analysis showed that IL-17-expressing exFoxp3 T (exFoxp3 TH17) cells accumulated in inflamed joints. The conversion of Foxp3(+)CD4(+) T cells to TH17 cells was mediated by synovial fibroblast-derived IL-6. These exFoxp3 TH17 cells were more potent osteoclastogenic T cells than were naive CD4(+) T cell-derived TH17 cells. Notably, exFoxp3 TH17 cells were characterized by the expression of Sox4, chemokine (C-C motif) receptor 6 (CCR6), chemokine (C-C motif) ligand 20 (CCL20), IL-23 receptor (IL-23R) and receptor activator of NF-κB ligand (RANKL, also called TNFSF11). Adoptive transfer of autoreactive, antigen-experienced CD25(lo)Foxp3(+)CD4(+) T cells into mice followed by secondary immunization with collagen accelerated the onset and increased the severity of arthritis and was associated with the loss of Foxp3 expression in the majority of transferred T cells. We observed IL-17(+)Foxp3(+) T cells in the synovium of subjects with active rheumatoid arthritis (RA), which suggests that plastic Foxp3(+) T cells contribute to the pathogenesis of RA. These findings establish the pathological importance of Foxp3 instability in the generation of pathogenic TH17 cells in autoimmunity.
IL-17 and Foxp3 double-expressing (DE) CD4 T lymphocytes are novel crossover immune cell population, but the presence and role of these cells in human intestinal inflammation is unclear. The aim of this study was to investigate the circulating IL-17 and Foxp3 DE CD4 T lymphocytes in patients with inflammatory bowel disease (IBD).
The entire cohort consisted of 79 subjects: 31 patients with Crohn's disease, 28 patients with ulcerative colitis, and 20 healthy control subjects (HC). IBD patients with evidence of active disease at endoscopy were entered into the study. Peripheral blood mononuclear cells were used for ex vivo and in vitro studies to assess the characteristics and generation of these novel cells and the function of circulating Foxp3 CD4 regulatory T lymphocytes (Treg) in patients with IBD compared with HC.
Patients with IBD had significantly higher prevalence of IL-17 and Foxp3 DE CD4 T lymphocytes compared with age- and gender-matched HC. These cells expressed RORγt. The ability of Treg cells to suppress autologous T-cell proliferation was reduced by approximately 60% in patients with IBD compared with HC. Increased generation of these DE cells was demonstrated by the modulation of cytokine environment of CD4 lymphocytes in vitro in patients with Crohn's disease.
Prevalence of circulating IL-17 and Foxp3 DE CD4 T cells is increased in patients with IBD. Coexpression of RORγt and Foxp3 in these cells implies conversion from Treg cells to Th17 cells. This is associated with a decreased suppressive function of Foxp3 CD4 T lymphocytes in patients with IBD.