Ursolic acid inhibits Th17 cell differentiation via STAT3/RORγt pathway and suppresses Schwann cell-mediated Th17 cell migration by reducing CXCL9/10 expression

Th17 cells represent important immune cells. Ursolic acid (UA) can regulate immune cell activities. This study was aimed to explore the effects of UA on Th17 cell differentiation and Schwann cell(SCs)-mediated migration and the potential mechanism. Naïve CD4⁺ T cells were isolated from rat peripheral blood, induced for Th17 cell differentiation, and treated with UA. The proportion of Th17 cells was detected by flow cytometry assay. SCs were co-cultured with Th17 cells. Th17 cell migration was detected by Transwell assay. The molecule expression was determined by Western blot and qRT-PCR. UA inhibited the Th17 cell differentiation and suppressed the STAT3/RORγt pathway. STAT3 overexpression up-regulated p-STAT3 and RORγt expression and promoted Th17 cell differentiation under the UA treatment. In LPS- and IFN-γ-stimulated-SCs, UA suppressed the expression of chemokines CXCL9/10, but had no significant effect of CCL20 expression. The expression CXCL9/10 receptor CXCR3 was higher in Th17 cells than that in Treg cells, while the expression CCL20 receptor CCR6 was lower in Th17 cells than that in Treg cells. UA, anti-CXCR3, and anti-CCR6 treatment inhibited SCs-mediated Th17 cell migration, and anti-CXCR3 exerted stronger inhibitory effect than Anti-CCR6. UA inhibited Th17 cell differentiation through STAT3/RORγt pathway and suppressed Th17 cell migration through down-regulating CXCL9/10 expression in SCs.     

STAT3 modulates CD4+ T mitochondrial dynamics and function in aging

Aging promotes numerous intracellular changes in T cells that impact their effector function. Our data show that aging promotes an increase in the localization of STAT3 to the mitochondria (mitoSTAT3), which promotes changes in mitochondrial dynamics and function and T-cell cytokine production. Mechanistically, mitoSTAT3 increased the activity of aging T-cell mitochondria by increasing complex II. Limiting mitoSTAT3 using a mitochondria-targeted STAT3 inhibitor, Mtcur-1 lowered complex II activity, prevented age-induced changes in mitochondrial dynamics and function, and reduced Th17 inflammation. Exogenous expression of a constitutively phosphorylated form of STAT3 in T cells from young adults mimicked changes in mitochondrial dynamics and function in T cells from older adults and partially recapitulated aging-related cytokine profiles. Our data show the mechanistic link among mitoSTAT3, mitochondrial dynamics, function, and T-cell cytokine production.     

CD4+T细胞的新亚型：Th17细胞及其生物效应

辅助性T细胞通常分为Th1型和Th2型.20余年来,该分类方法形成了理解CD4 T细胞免疫生物学、固有免疫和适应性免疫调节理论的框架.近来研究发现,机体存在一种新型的不同于1型和2型的CD4 效应T细胞——辅助性17细胞(Thelp 17,Th 17),该细胞是由天然T细胞前体分化而来,具有独立的分化和发育调节机制,并特异性地产生白介素17(interleukin 17,IL-17)效应因子,在自身免疫性疾病和感染性疾病中发挥重要调节作用.这将对深入研究机体免疫调节、免疫病理和机体防御反应机制具有重要意义.就这种新型的辅助性T细胞的产生、发育分化机制和免疫调节效应研究进展做一简要综述.     

CD4+ T cell responses to HLA-DP5-restricted wild-type sequence p53 peptides in patients with head and neck cancer

Wild-type sequence (wt) p53 peptides are attractive candidates for broadly applicable cancer vaccines. Evidence has been accumulating which indicates that CD4+ Th cells have an important role in generating and maintaining antitumor immune responses. To elucidate the nature of CD4+ Th responses to wt p53 epitopes in patients with squamous cell carcinoma of the head and neck (SCCHN), peripheral blood mononuclear cells (PBMCs) from HLA-DP5+ patients were stimulated with HLA-DP5-restricted wt p53 peptides, p53_108–122 or p53_153–166, and tested for the release of IFN-γ and IL-5 in ELISPOT assays. Immunohistochemistry for p53 accumulation in tumors, and ELISA for serum antibodies to p53 were also performed. Eleven (57.9%) of 19 HLA-DP5+ patients but none of 5 healthy donors had detectable Th1 and/or Th2 responses to wt p53 peptides by ELISPOT assay. Among these 11 responding patients, 9 (81.8%) and all 11 (100%) patients had a tumor burden and p53 accumulation, respectively. On the other hand, two responding patients were in post-operative condition. Interestingly, among nine patients with a tumor burden, four patients with early disease showed either Th1-polarized or mixed Th1/Th2 responses, while five patients with advanced disease showed either Th2-polarized or mixed Th1/Th2 responses. Our results suggest that wt p53_108–122 and p53_153–166 peptides stimulate both Th1- and Th2-type CD4+ T cell responses in patients with SCCHN, and anti-p53 Th responses may persist even after surgical resection of the tumor; however, the presence of a tumor and its progression may affect the nature of immune responses to wt p53 peptides.     

CD4+CD25+FoxP3+ 调节性T 细胞与黑龙江省HIV/AIDS 患者病情 相关性的研究

目的:比较黑龙江省HIV/AIDS患者与健康对照者(healthy controls,HCs)外周血CD4+CD25+FoxP3+调节性T细胞数量、免疫抑制功能的变化,探讨CD4+CD25+FoxP3+调节性T细胞在HIV/AIDS感染过程中的作用。方法:采用流式细胞仪检测21例HIV/AIDS患者及20例健康对照组的外周血CD4+CD25+FoxP3+调节性T细胞数量的百分比及绝对数量;采用共同培养方法检测HIV/AIDS患者外周血CD4+CD25+FoxP3+调节性T细胞免疫抑制功能的变化;实时荧光定量聚合酶链反应(RT-FQ-PCR)检测HIV/AIDS患者外周血CD4+CD25+FoxP3+调节性T细胞中FoxP3mRNA的表达。结果:黑龙江省HIV/AIDS患者外周血CD4+CD25+FoxP3+调节性T细胞比率明显高于HCs(P<0.01),而CD4+CD25+FoxP3+调节性T细胞的绝对计数显著下降,且与CD4+T细胞绝对计数成反比;混合淋巴细胞共同培养结果显示,HIV/AIDS患者外周血CD4+CD25+FoxP3+调节性T细胞的抑制功能无明显变化;HIV/AIDS患者外周血CD4+CD25+FoxP3+调节性T细胞的FoxP3 mRNA相对表达量无显著变化。结论:黑龙江省HIV/AIDS患者CD4+CD25+FoxP3+调节性T细胞的数量变化与病情相关。     

HCV-specific interleukin-21+CD4+ T cells responses associated with viral control through the modulation of HCV-specific CD8+ T cells function in chronic hepatitis C patients

Interleukin-21 (IL-21)+CD4+ T cells are involved in the immune response against hepatitis B virus (HBV) by secreting IL-21. However, the role of IL-21+CD4+ T cells in the immune response against chronic hepatitis C (CHC) virus infection is poorly understood. This study aimed to investigate the role of IL-21+CD4+ T cells in CHC patients and the potential mechanisms. The study subjects included nineteen CHC patients who were grouped by viral load (low, < 10⁶ RNA copies/ml, n = 8; high, > 10⁶ RNA copies/ml, n = 11). The peripheral frequency of HCV-specific IL-21+CD4+ T cells was higher in the low viral load group and was negatively correlated with the serum HCV RNA viral load in all CHC patients. Meanwhile, IL-21+ cells accumulated in the liver in the low viral load group. In vitro, IL-21 treatment increased the expression of proliferation markers and cytolytic molecules on HCV-specific CD8+ T cells. In summary, these findings suggest that HCV-specific IL-21+CD4+ T cells might contribute to HCV control by rescuing HCV-specific CD8+ T cells in CHC patients.     

LncRNA‐miRNA network analysis across the Th17 cell line reveals biomarker potency of lncRNA NEAT1 and KCNQ1OT1 in multiple sclerosis

Differentiation of CD⁴⁺ T cells into Th17 cells is an important factor in the onset and progression of multiple sclerosis (MS) and Th17/Treg imbalance. Little is known about the role of lncRNAs in the differentiation of CD⁴⁺ cells from Th17 cells. This study aimed to analyse the lncRNA‐miRNAs network involved in MS disease and its role in the differentiation of Th17 cells. The lncRNAs in Th17 differentiation were obtained from {"type":"entrez-geo","attrs":{"text":"GSE66261","term_id":"66261"}}GSE66261 using the GEO datasets. Differential expression of lncRNAs in Th17 primary cells compared to Th17 effector cells was investigated by RNA‐seq analysis. Next, the most highlighted lncRNAs in autoimmune diseases were downloaded from the lncRNAs disease database, and the most critical miRNA was extracted by literature search. Then, the lncRNA‐miRNA interaction was achieved by the Starbase database, and the ceRNA network was designed by Cytoscape. Finally, using the CytoHubba application, two hub lncRNAs with the most interactions with miRNAs were identified by the MCODE plug‐in. The expression level of genes was measured by qPCR, and the plasma level of cytokines was analysed by ELISA kits. The results showed an increase in the expression of NEAT1, KCNQ1OT1 and RORC and a decrease in the expression of FOXP3. In plasma, an upregulation of IL17 and a downregulation of TGFB inflammatory cytokines were detected. The dysregulated expression of these genes could be attributed to relapsing‐remitting MS (RR‐MS) patients and help us understand MS pathogenesis better.     

CD4+CD25+调节性T细胞的外周维持

CD4 CD25 调节性T细胞作为一种抑制性T细胞功能亚群,在维持机体的免疫自稳和免疫耐受方面发挥了关键作用。该作用的发挥与其外周细胞库的维持密切相关。新近的研究显示CD4 CD25 调节性T细胞主要通过两种机制来维持其外周细胞库,一些功能分子参与其中。     

CD39+ Regulatory T cells suppress generation and differentiation of Th17 cells in human malignant pleural effusion via a LAP-dependent mechanism

Background

Both regulatory T cells (Tregs) and T helper IL-17-producing cells (Th17 cells) have been found to be involved in human malignancies, however, the possible implication of Tregs in regulating generation and differentiation of Th17 cells in malignant pleural effusion remains to be elucidated.

Methods

The numbers of both CD39⁺Tregs and Th17 cells in malignant pleural effusion and peripheral blood from patients with lung cancer were determined by flow cytometry. The regulation and mechanism of Tregs on generation and differentiation of Th17 cells were explored.

Results

Both CD39⁺Tregs and Th17 cells were increased in malignant pleural effusion when compared with blood, and the numbers of CD39⁺Tregs were correlated negatively with those of Th17 cells. It was also noted that high levels of IL-1β, IL-6, and TGF-β1 could be observed in malignant pleural effusion when compared the corresponding serum, and that pleural CD39⁺Tregs could express latency-associated peptide on their surface. When naïve CD4⁺ T cells were cocultured with CD39⁺Tregs, Th17 cell numbers decreased as CD39⁺Treg numbers increased, addition of the anti-latency-associated peptide mAb to the coculture reverted the inhibitory effect exerted by CD39⁺Tregs.

Conclusions

Therefore, the above results indicate that CD39⁺Tregs inhibit generation and differentiation of Th17 cells via a latency-associated peptide-dependent mechanism.     

Peripheral CD4CD8 cells are the activated T cells expressed granzyme B (GrB), Foxp3, interleukin 17 (IL-17), at higher levels in Th1/Th2 cytokines

Peripheral CD4⁺CD8⁺ T cells have been identified as a T cell subset existing in animals and humans. However, the characterization of CD4⁺CD8⁺ T cells, their relationship with T memory (T_M), T effector (T_E), Th1/Th2, Treg and Th-17, remain unclear. This study was to characterize the CD4⁺CD8⁺ T cells. The results from human subjects showed that activated T cells were CD4⁺CD8⁺ T cells, comprised CD4^hiCD8^lo, CD4^hiCD8^hi and CD4^loCD8^hi subsets. They expressed CD62L^hi/lo, granzyme B (GrB), CD25, Foxp3, interleukin 17 (IL-17) and the cytokines of both Th1 and Th2, and had cytolytic function. These findings suggested that CD4⁺CD8⁺ T cells had over-lap function while they kept diversity, and that T cells could be divided into two major populations: activated and inactivated. Hence, the hypotheses of Th1/Th2, Treg and Th-17 might reflect the positive/negative feedback regulation of immune system. When compared to GrB⁺CD62L^lo T effector (T_E) cells, GrB⁺CD62L^hi T central memory effector (T_CME) cells had a quicker response to virus without CD62L loss.     

Expression of PD‐1/LAG‐3 and cytokine production by CD4+ T cells during infection with Plasmodium parasites

CD4⁺ T cells play critical roles in protection against the blood stage of malarial infection; however, their uncontrolled activation can be harmful to the host. In this study, in which rodent models of Plasmodium parasites were used, the expression of inhibitory receptors on activated CD4⁺ T cells and their cytokine production was compared with their expression in a bacterial and another protozoan infection. CD4⁺ T cells from mice infected with P. yoelii 17XL, P yoelii 17XNL, P. chabaudi, P. vinckei and P. berghei expressed the inhibitory receptors, PD‐1 and LAG‐3, as early as 6 days after infection, whereas those from either Listeria monocytogenes‐ or Leishmania major‐infected mice did not. In response to T‐cell receptor stimulation, CD4⁺ T cells from mice infected with all the pathogens under study produced high concentrations of IFN‐γ. IL‐2 production was reduced in mice infected with Plasmodium species, but not in those infected with Listeria or Leishmania. In vitro blockade of the interaction between PD‐1 and its ligands resulted in increased IFN‐γ production in response to Plasmodium antigens, implying that PD‐1 expressed on activated CD4⁺ T cells actively inhibits T cell immune responses. Studies using Myd88^?/?, Trif^?/? and Irf3^?/? mice showed that induction of these CD4⁺ T cells and their ability to produce cytokines is largely independent of TLR signaling. These studies suggest that expression of the inhibitory receptors PD‐1 and LAG‐3 on CD4⁺ T cells and their reduced IL‐2 production are common characteristic features of Plasmodium infection.

     

IL-17 inhibits human Th1 differentiation through IL-12Rβ2 downregulation

Th17 cells are critical in adaptive immunity and autoimmune disease. The polarized development of Th17, Th1 and Th2 cells is dependent on counterregulatory effects on each other. Whereas IFN-γ inhibits Th17 development, the effect of IL-17 in human Th1 development is not known. We report a novel negative regulatory role of IL-17 on IL-12Rβ2 expression associated with reduced IL-12 responsiveness. IL-17 decreased IL-12-induced IFN-γ expression in PBMC and developing Th1 cells, associated with a selective reduction in IL-12Rβ2, and not IL-23R, IL-12Rβ1 or T-bet. Counterregulatory effects of human Th17 on Th1 lineage cytokines may contribute to lineage divergence. In autoimmune disease, IL-17 may reinforce its own developmental programme by reducing IL-12 responsiveness, thus limiting inhibitory effects of IFN-γ on Th17 development.     

The role of CD4 T cell help for CD8 CTL activation

CD4 T cells play an important role in the initiation and persistence of CD8 T cells responses. In this review, we report on and evaluate the mechanisms by which CD4 T cells contribute to activation of CD8 T cells and the signal pathways of the down-streaming events after CD4 T cell help.     

CD4+T细胞分化与表观遗传作用

DNA甲基化、染色质重塑等表观遗传作用对CD4^ T细胞向Th1和Th2的分化有重要的影响,现对Th1细胞表达IFN-γ以及Th2细胞表达IL-4／IL-13在基因转录水平的调节作用给予概述,重点阐述相关转录因子、酶以及蛋白质复合物所发挥的表观遗传调节作用的可能机制。     

A HLA-DQ5 restricted Melan-A/MART-1 epitope presented by melanoma tumor cells to CD4+ T lymphocytes

Melan-A/MART1 is a melanocytic differentiation antigen expressed by tumor cells of the majority of melanoma patients and, as such, is considered as a good target for melanoma immunotherapy. Nonetheless, the number of class I and II restricted Melan-A epitopes identified so far remains limited. Here we describe a new Melan-A/MART-1 epitope recognized in the context of HLA-DQa1*0101 and HLA-DQb1*0501, -DQb1*0502 or -DQb1*0504 molecules by a CD4+ T cell clone. This clone was obtained by in vitro stimulation of PBMC from a healthy donor by the Melan-A51-73 peptide previously reported to contain a HLA-DR4 epitope. The Melan-A51-73 peptide, therefore contains both HLA-DR4 and HLA-DQ5 restricted epitope. We further show that Melan-A51-63 is the minimal peptide optimally recognized by the HLA-DQ5 restricted CD4+ clone. Importantly, this clone specifically recognizes and kills tumor cell lines expressing Melan-A and either HLA-DQb1*0501, -DQb1*0504 or -DQb1*0502 molecules. Moreover, we could detect CD4+ T cells secreting IFN-gamma in response to Melan-A51-63 and Melan-A51-73 peptides among tumor infiltrating and blood lymphocytes from HLA-DQ5+ patients. This suggests that spontaneous CD4+ T cell responses against this HLA-DQ5 epitope occur in vivo. Together these data significantly increase the fraction of melanoma patients susceptible to benefit from a Melan-A class II restricted vaccine approach.