The Functional Stability of FOXP3 and RORγt in Treg and Th17 and Their Therapeutic Applications

The association of lymphocyte with hypothyroidism in obstructive sleep apnea

PURPOSE

Obstructive sleep apnea (OSA) is a common sleep-breathing disorder. Numerous investigations have found a strong inherent relationship between OSA and hypothyroidism. Studies suggest that lymphocytes may be involved in the development of hypothyroidism in patients with OSA. This study aimed to assess the association between lymphocytes and hypothyroidism in OSA patients.

PATIENTS AND METHODS

This study involved 920 patients with OSA who underwent nocturnal sleep monitoring, thyroid function testing, and routine blood tests. In patients with OSA, logistic regression analysis indicated independent predictors of hypothyroidism. The cutoff level of lymphocyte count was determined using a receiver operating characteristic (ROC) analysis to predict the occurrence of hypothyroidism in individuals with OSA.

RESULTS

This study comprised 920 OSA patients (617 males and 303 women), 879 with normal thyroid function, and 41 with hypothyroidism, with a hypothyroidism incidence of 4.46%. In the entire OSA population and male OSA patients, the number of lymphocytes was significantly higher in the hypothyroid group than in the control group (p = 0.002 and 0.020, respectively). In addition, among the OSA population younger than 60 years old and patients with mild to moderate OSA, lymphocytes were found to be considerably more in the hypothyroid group than in the euthyroid group. Lymphocyte count, ESS, and sex were all independent predictors of hypothyroidism development in OSA patients. According to ROC curve analysis, the risk of hypothyroidism increases with increasing lymphocyte count in the total patient population, with an optimal diagnostic cutoff point of 2.5 (× 10*9/L).

CONCLUSIONS

The prevalence of hypothyroidism in patients with OSA increases as the number of lymphocytes increases. Lymphocyte count can be used as an independent predictor of the occurrence of hypothyroidism, and it has a diagnostic value for OSA combined with hypothyroidism.

Sex-Specific Immune Responses to Seasonal Influenza Vaccination in Diabetic Individuals: Implications for Vaccine Efficacy

Seasonal influenza vaccination has different implications on the immune response depending on the comorbidities. Diabetes is one such critical disease that increases the patient's susceptibility to influenza and suppresses vaccine efficacy and immunity. The sex of the individuals also plays a definitive role in the immune responses to both the vaccine and the infection. This study aims to understand the efficacy of the seasonal vaccine against influenza in diabetic groups and undergoing immune mechanisms in different sexes (females and males). In this study, we are reporting about a switching of the immune response of the infected and vaccinated diabetic females towards stronger Th1/Th17 responses with suppressed humoral immunity. They show increased cDC1, enhanced proinflammatory activities within T cells, CD8T activation, Th17 proliferation, and the majority of IgG2 antibody subtypes with reduced neutralization potential. Males with diabetes exhibit enhanced humoral Th2-immunity than the nondiabetic group. They exhibit higher cDC2, and DEC205 levels within them with an increase in plasma B lymphocytes, higher IgG1 subtypes in plasma cells, and influenza-hemagglutinin-specific IgG titer with stronger virus neutralization potential. Males with diabetes recovered better than the females as observed from the changes in their body weight. This study highlights the critical immune mechanisms and sex-specific swapping of their preferred immune response pathways against influenza after vaccination during diabetes. We propose a need for a sex-specific customized vaccine regimen to be implemented against influenza for individuals having diabetes to exploit the manifested strength and weakness in their protective immunity.

LKB1 isoform expression modulates T cell plasticity downstream of PKCθ and IL-6

Following activation, CD4 T cells undergo metabolic and transcriptional changes as they respond to external cues and differentiate into T helper (Th) cells. T cells exhibit plasticity between Th phenotypes in highly inflammatory environments, such as colitis, in which high levels of IL-6 promote plasticity between regulatory T (Treg) cells and Th17 cells. Protein Kinase C theta (PKCθ) is a T cell-specific serine/threonine kinase that promotes Th17 differentiation while negatively regulating Treg differentiation. Liver kinase B1 (LKB1), also a serine/threonine kinase and encoded by Stk11, is necessary for Treg survival and function. Stk11 can be alternatively spliced to produce a short variant (Stk11_S) by transcribing a cryptic exon. However, the contribution of Stk11 splice variants to Th cell differentiation has not been previously explored. Here we show that in Th17 cells, the heterogeneous ribonucleoprotein, hnRNPLL, mediates Stk11 splicing into its short splice variant, and that Stk11_S expression is diminished when Hnrnpll is depleted using siRNA knock-down approaches. We further show that PKCθ regulates hnRNPLL and, thus, Stk11_S expression in Th17 cells. We provide additional evidence that exposing induced (i)Tregs to IL-6 culminates in Stk11 splicing downstream of PKCθAltogether our data reveal a yet undescribed outside-in signaling pathway initiated by IL-6, that acts through PKCθ and hnRNPLL to regulate Stk11 splice variants and facilitate Th17 cell differentiation. Furthermore, we show for the first time, that this pathway can also be initiated in developing iTregs exposed to IL-6, providing mechanistic insight into iTreg phenotypic stability and iTreg to Th17 cell plasticity.

lncRNA GAS5 and RUNX1 Genes in Children With Primary Immune Thrombocytopenia

We aimed to evaluate the expression levels and the prognostic value of growth arrest specific 5 (GAS5) and runt-related transcription factor 1 (RUNX1) genes in children with ITP. This prospective cohort study included 100 patients with newly diagnosed ITP (patient group) and 100 healthy children of matched age and sex (control group). We evaluated the expression levels of both GAS5 and RUNX1 genes at the time of diagnosis before the introduction of treatment. GAS5 was under-expressed, while RUNX1 was over-expressed among the newly diagnosed ITP children compared with the control group. Patients with GAS5 levels >0.50 had a significantly faster recovery compared with patients with levels≤0.50 while patients with levels of RUNX1≤2.6 had a significantly faster recovery compared with patients with levels >2.6. The best cut-off values of GAS5 and RUNX1 to predict complete recovery of ITP were ˃0.40 and ˂3.18, respectively, yielding a sensitivity of 76.47% and 79.41%, respectively. The best cut-off values of GAS5 and RUNX1 expression that predict chronic ITP were ˂0.17 and ˃4.1, respectively, yielding sensitivity of 88.89% and 77.78%, respectively. GAS5 and RUNX1 could be useful markers in children with primary ITP to predict disease course.

Gal-9/Tim-3 signaling pathway activation suppresses the generation of Th17 cells and promotes the induction of Foxp3+ regulatory T cells in renal ischemia-reperfusion injury

CD4⁺ T cells mediate the pathogenesis of renal ischemia-reperfusion injury (IRI). Emerging research suggests that a Th17/regulatory T cell (Treg) imbalance plays a pivotal role in the development of renal IRI. A recently identified negative checkpoint protein, T cell immunoglobulin domain and mucin domain family 3 (Tim-3), inhibits the immune response by binding to its ligand, galectin-9 (Gal-9). However, the role of the Gal-9/Tim-3 signaling pathway in the regulation of CD4⁺ T cell subsets in renal IRI remains unclear. In this study, we investigated the effect of the Gal-9/Tim-3 signaling pathway on Th17/Treg subsets in renal IRI using a mouse model. Renal IRI induced the expression of Gal-9 in renal tubular epithelial cells and increased the proportion of Tim-3⁺ Th17 cells and Tim-3⁺ forkhead box P3 (Foxp3)⁺ Treg cells in the ischemia-reperfusion (IR) kidneys. Administration of rAAV9-Gal-9 suppressed kidney inflammation, reduced the mortality of mice with renal IRI, increased Foxp3⁺ Treg cells, and reduced Th17 cells. In contrast, the blockade of Tim-3 in vivo using an anti-Tim-3 monoclonal antibody aggravated renal inflammation, decreased Foxp3⁺ Treg cells, and promoted Th17 cells. Thus, Gal-9/Tim-3 signaling pathway activation may protect against renal IRI by inhibiting Th17 cell production and inducing Foxp3⁺ Treg cell expansion. Our study suggests that the Gal-9/Tim-3 signaling pathway may be targeted by immunotherapy in renal IRI.

Mesenchymal Stem Cells in Acquired Aplastic Anemia: The Spectrum from Basic to Clinical Utility

Aplastic anemia (AA), a rare but potentially life-threatening disease, is a paradigm of bone marrow failure syndromes characterized by pancytopenia in the peripheral blood and hypocellularity in the bone marrow. The pathophysiology of acquired idiopathic AA is quite complex. Mesenchymal stem cells (MSCs), an important component of the bone marrow, are crucial in providing the specialized microenvironment for hematopoiesis. MSC dysfunction may result in an insufficient bone marrow and may be associated with the development of AA. In this comprehensive review, we summarized the current understanding about the involvement of MSCs in the pathogenesis of acquired idiopathic AA, along with the clinical application of MSCs for patients with the disease. The pathophysiology of AA, the major properties of MSCs, and results of MSC therapy in preclinical animal models of AA are also described. Several important issues regarding the clinical use of MSCs are discussed finally. With evolving knowledge from basic studies and clinical applications, we anticipate that more patients with the disease can benefit from the therapeutic effects of MSCs in the near future.

Sishen Wan Treats Ulcerative Colitis in Rats by Regulating Gut Microbiota and Restoring the Treg/Th17 Balance

Objective

This study was aimed to explore the mechanism of Sishen Wan (SSW) in treating ulcerative colitis (UC) in a rat model of spleen-kidney yang deficiency pattern by regulating gut microbiota and the content of butyric acid in short-chain fatty acid (SCFAs) and restoring regulatory T (Treg)/T helper type 17 (Th17) balance from the perspective of the correlation between gut microbiota and immune function.

Methods

The UC rat model of spleen-kidney yang deficiency pattern was established by the method of combining disease and syndrome (intragastric administration of senna leaf, subcutaneous injection of hydrocortisone, and enema with 2,4-dinitrobenzenesulfonic acid (DNBS)/ethanol solution). After successful modeling, rats were randomly divided into six groups: the blank group, model group, low-, middle-, and high-dose Sishen Wan groups, and mesalazine group. Samples were taken after continuous administration for 3 weeks. The general conditions and body weight of the rats were observed and recorded, and the disease activity index (DAI) score was calculated. Colonic mucosal injury was observed, and a colonic mucosal damage index (CMDI) score was calculated. Histopathological changes in colon tissues were determined by hematoxylin and eosin (H&E) staining, and the histopathological score (HS) was calculated. The serum levels of transforming growth factor-β1 (TGF-β1), interleukin (IL)-6, IL-10, and IL-17 were determined by enzyme-linked immunosorbent assay (ELISA) assays. The expression of TGF-β1, signal transducer and activator of transcription 3 (STAT3), and peroxisome proliferator-activated receptor γ (PPARγ) was determined by Western blot analysis. The proportion of Th17 and Treg cells in colon tissue was determined by flow cytometry. The relative abundance of gut microbiota was determined by 16S rDNA sequencing, and the concentration of butyric acid of SCFAs was determined by gas chromatography-mass spectrometry (GC-MS).

Results

Administration of SSW significantly improved the pathological changes of colon tissue in UC rats and could attenuate the DAI and CMDI scores, and the HS. SSW significantly decreased the serum levels of IL-6 and IL-17 and increased the serum levels of TGF-β1 and IL-10. In addition, SSW increased the expression of TGF-β1 and PPARγ and decreased the expression of STAT3 in colon tissue in a dose-dependent manner. Furthermore, SSW significantly decreased the proportion of Th17 cells and increased the proportion of Treg cells in colon tissue. Additionally, SSW altered the gut microbiota, including an increase in the relative abundance of Firmicutes and a decrease in Bacteroidota at the phylum level and an increase in the relative abundance of Lactobacillus at the genus level. Moreover, SSW significantly increased the concentration of butyric acid.

Conclusions

Combined, these data suggested that SSW increased the relative abundance of firmicutes and the level of butyric acid and restored the balance of Treg/Th17 immune axis and gut homeostasis, thus delaying the progress of UC.

Propofol maintains Th17/Treg cell balance in elderly patients undergoing lung cancer surgery through GABAA receptor

Propofol is widely used in clinical anesthesia due to its advantages of rapid onset and less adverse reactions. This study focused on the role of propofol in the balance of Th17/Treg in elderly patients with lung cancer during perioperative period. Patients undergoing lung cancer surgery were anesthetized by propofol or sevoflurane. Veinal blood was collected at different time points to evaluate the changes of Th17/Treg cell. Propofol better maintained the balance of Th17/Treg in vivo. The peripheral blood of patients with lung cancer was collected in vitro before surgery. Cluster of differentiation (CD)4⁺ T cells were obtained and then treated with propofol at different concentrations and γ-aminobutyric acid A (GABAA) receptor antagonists. Propofol affected Th17/Treg cell balance by increasing Th17 cells, decreasing Treg cells, thus elevating Th17/Treg ratio, and inhibited invasion and migration of lung cancer cells through GABAA receptor, which was counteracted by GABAA receptor inhibitors. Subsequently, tumor in situ model of lung cancer in aged mice was established. Propofol anesthetized mice had lower change of Th17/Treg ratio, higher survival rate and less metastasis. In brief, propofol regulated balance of Th17/Treg in elderly patients undergoing lung cancer surgery through GABAA receptor. Additionally, propofol could inhibit metastasis of lung cancer.

Pivotal role of PD-1/PD-L1 immune checkpoints in immune escape and cancer progression: Their interplay with platelets and FOXP3+Tregs related molecules, clinical implications and combinational potential with phytochemicals

Immune checkpoint proteins including programmed cell death protein 1 (PD-1), its ligand PD-L1 and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) are involved in proliferation, angiogenesis, metastasis, chemoresistance via immune escape and immune tolerance by disturbing cytotoxic T cell activation. Though many clinical trials have been completed in several cancers by using immune checkpoint inhibitors alone or in combination with other agents to date, recently multi-target therapy is considered more attractive than monotherapy, since immune checkpoint proteins work with other components such as surrounding blood vessels, dendritic cells, fibroblasts, macrophages, platelets and extracellular matrix within tumor microenvironment. Thus, in the current review, we look back on research history of immune checkpoint proteins and discuss their associations with platelets or tumor cell induced platelet aggregation (TCIPA) and FOXP3+ regulatory T cells (Tregs) related molecules involved in immune evasion and tumor progression, clinical implications of completed trial results and signaling networks by phytochemicals for combination therapy with immune checkpoint inhibitors and suggest future research perspectives.

Research progress on Th17 and T regulatory cells and their cytokines in regulating atherosclerosis

Background

Coronary heart disease due to atherosclerosis is the leading cause of death worldwide. Atherosclerosis is considered a chronic inflammatory state in the arterial wall that promotes disease progression and outcome, and immune cells play an important role in the inflammatory process.

Purpose

We review the mechanisms of CD4+ T subsets, i.e., helper T17 (Th17) cells and regulatory T cells (Tregs), in regulating atherosclerosis, focusing on the role of interleukin (IL)-17, IL-10, and other cytokines in this disease and the factors influencing the effects of these cytokines.

Results

IL-17 secreted by Th17 cells can promote atherosclerosis, but few studies have reported that IL-17 can also stabilize atherosclerotic plaques. Tregs play a protective role in atherosclerosis, and Th17/Treg imbalance also plays an important role in atherosclerosis.

Conclusion

The immune response is important in regulating atherosclerosis, and studying the mechanism of action of each immune cell on atherosclerosis presents directions for the treatment of atherosclerosis. Nevertheless, the current studies are insufficient for elucidating the mechanism of action, and further in-depth studies are needed to provide a theoretical basis for clinical drug development.

Low Activation of CD8+ T Cells in response to Viral Peptides in Mexican Patients with Severe Dengue

It is acknowledged that antiviral immune response contributes to dengue immunopathogenesis. To identify immunological markers that distinguish dengue fever (DF) and dengue hemorrhagic fever (DHF), 113 patients with confirmed dengue infection were analyzed at 6 or 7 days after fever onset. Peripheral blood mononuclear cells (PBMC) were isolated, lymphocyte subsets and activation biomarkers were identified by flow cytometry, and differentiation of T helper (Th) lymphocytes was achieved by the relative expression analysis of T-bet (Th1), GATA-3 (Th2), ROR-γ (Th17), and FOXP-3 (T regulatory) transcription factors quantified by real-time PCR. CD8+, CD40L+, and CD45+ cells show higher numbers in DF compared to DHF patients, whereas CD4+, CD19+, and CD25+ cells show higher numbers in DHF than DF patients. High expression of GATA-3 accompanied by low expression of T-bet indicates predominance of Th2 response. In addition, higher expression of FOXP-3 and reduced functional cytotoxic T cells (CD8+perforin+) were observed in DHF patients. In further experiments, PBMC were stimulated ex vivo with dengue virus E, NS3, NS4, and NS5 peptides, and proliferating T cell subsets were determined. Lower proliferative responses to NS3 and NS4 peptides and reduced CD8+ cytotoxic T cells were observed in DHF patients. Our results suggest that immune response to dengue is dysregulated with predominance of CD4+ T cells, low activation of Th1 cells, and downregulation of the antiviral cytotoxic activity during severe dengue, likely induced by regulatory T cells.

Effects of 15-Lipoxygenase Overexpressing Adipose Tissue Mesenchymal Stem Cells on The Th17 / Treg Plasticity

15-lipoxygenase (15-LOX) is a critical enzyme that allows the direction of arachidonic acid metabolism to change from inflammation into the resolution. This study aims to reveal how the immunomodulation properties of mesenchymal stem cells (MSC) alter by the 15-LOX overexpression. For this purpose, peripheral blood mononuclear cells (PBMCs) isolated from seven healthy volunteers, and both MSCs and 15-LOX overexpressing MSCs (^15-LOXMSCs) were co-cultured at different cell ratios (1/1, 1/5 and 1/10). Alterations of CD4⁺Tbet⁺, CD4⁺Gata3⁺, CD4⁺RoRC2⁺, and CD4⁺FoxP3⁺ lymphocyte frequencies were detected by flow cytometry, and IFN-γ, IL-4, IL-6, IL-10, IL-17a, TGF-β and LXA₄ levels of medium supernatants were measured by ELISA method. According to our findings, MSC and ^15-LOXMSCs have a suppressive effect on PHA activated PBMCs. However, as the ratio of PBMCs increased, the effects of ^15-LOXMSCs increased significantly, while the effects of MSCs decreased. The most notable effect of the 15-LOX modification was the significant reduction in IL-6, IL-10 and IL-17a expression and the accompanying increase in TGF-β and LXA₄ levels. We also observed a similar situation between CD4⁺RoRC2⁺ and CD4⁺FoxP3⁺ cell frequencies. These data suggested that the effects of MSCs on the balance of Th17 / Treg could change by the 15-LOX overexpression, and this might be in favor of the Treg cells.

Erxian Decoction modulates Th17/Treg cells differentiation through LFA-1/ICAM-1/STAT3 pathway in menopausal dry eye disease

With the development of modern societies and the ageing of the population, the treatment of menopausal dry eye disease (MDED) has become a thorny issue for the medical profession. Erxian Decoction (EXD) is a traditional Chinese medicine prescription, which has performed good clinical effect on dry eye disease. In this research, we purposed to investigate the molecular mechanisms of EXD for the treatment of MDED. A MDED rat model was established, the results indicated that high concentration of EXD could significantly improve the tear secretion and tear film stability of the animal model. Next, we found that EXD worked through the LFA-1/ICAM-1/STAT3 pathway in the body, and EXD could regulate IL-17, IL-10, CTLA-4 and TGF-β1 to get Th17/Treg balance. In vitro experiments, the results indicated that EXD affected the differentiation of CD4⁺ T cells into Th17/Treg cells by inhibiting the expression and activation of LFA-1 on CD4⁺ T cells, thus exerting immunotherapy effect. Our research provided the experimental basis and associated mechanisms for the clinical application of EXD in dry eye disease.

IRF4 is Correlated with the Conversion to a Th17-Like Phenotype in Regulatory T Cells from the Malignant Pleural Effusion

Background

RORγt⁺Foxp3⁺ (Th17-like) Tregs are a plastic Treg subset implicated in immune-related diseases; however, the mechanism of Treg phenotypic transformation in malignant pleural effusion (MPE) has not been elucidated.

Methods

The percentage of CD4⁺CD25⁺Foxp3⁺Helios⁺ and RORγt⁺Foxp3⁺ Tregs from peripheral blood and pleural effusion mononuclear cells were measured. The level of interferon regulatory factor 4 (IRF4) mRNA expression was detected by quantitative real-time reverse transcription polymerase chain reaction. The effects of IRF4 on the induction of Tregs from patients with non-small cell lung cancer (NSCLC) were evaluated in vitro. Correlation assays between IRF4 expression and the frequency of RORγt⁺Foxp3⁺ Tregs were performed.

Results

The frequency of CD4⁺CD25⁺Foxp3⁺Helios⁺ Tregs and CD4⁺RORγt⁺ Th17 cells was both increased in the MPE of NSCLC patients. The group of double-positive Foxp3⁺RORγt⁺ Treg phenotype were identified in the pleural effusion. A significant increase in the frequency of Foxp3⁺RORγt⁺ Tregs was found in MPE compared with the non-malignant pleural effusion (NPE). Compared to NPE, the relative level of IRF4 expression was increased in the MPE. IRF4 expression was positively associated with the frequency of Foxp3⁺RORγt⁺ Tregs in the PE. In vitro, the level of Helios mRNA and protein expression was reduced in induced Tregs following IRF4 over-expression. Additionally, the level of RORγt protein expression was substantially increased. However, ectopic Helios expression in induced Tregs reversed the effects induced by enhanced IRF4 expression.

Conclusion

IRF4 may serve as a potential molecule that promotes the conversion of regulatory T cells from MPE to a Th17-like phenotype by modulating Helios.

Improvement of Treg immune response after treatment with tocilizumab in giant cell arteritis

Objectives

To study the percentage, suppressive function and plasticity of Treg in giant cell arteritis (GCA), and the effects of glucocorticoids and tocilizumab.

Methods

Blood samples were obtained from 40 controls and 43 GCA patients at baseline and after treatment with glucocorticoids + IV tocilizumab (n = 20) or glucocorticoids (n = 23). Treg percentage and phenotype were assessed by flow cytometry. Suppressive function of Treg was assessed by measuring their ability to inhibit effector T‐cell (Teff) proliferation and polarisation into Th1 and Th17 cells.

Results

Treg (CD4⁺CD25^highFoxP3⁺) frequency in total CD4⁺ T cells was decreased in active GCA patients when compared to controls (2.5% vs. 4.7%, P < 0.001) and increased after treatment with tocilizumab but worsened after treatment with glucocorticoids alone. Treg lacking exon 2 of FoxP3 were increased in GCA patients when compared to controls (23% vs. 10% of total Treg, P = 0.0096) and normalised after treatment with tocilizumab + glucocorticoids but not glucocorticoids alone. In GCA patients, Treg were unable to control Teff proliferation and induced ˜50% increase in the amount of IL‐17⁺ Teff, which was improved after in vitro blockade of the IL‐6 pathway by tocilizumab.

Conclusion

This study reports quantitative and functional disruptions in the regulatory immune response of GCA patients and demonstrates that, unlike glucocorticoids, tocilizumab improves Treg immune response.

Bone Morphogenic Proteins Are Immunoregulatory Cytokines Controlling FOXP3+ Treg Cells

Bone morphogenic proteins (BMPs) are members of the transforming growth factor β (TGF-β) cytokine family promoting differentiation, homeostasis, and self-renewal of multiple tissues. We show that signaling through the bone morphogenic protein receptor 1α (BMPR1α) sustains expression of FOXP3 in T_reg cells in peripheral lymphoid tissues. BMPR1α signaling promotes molecular circuits supporting acquisition and preservation of T_reg cell phenotype and inhibiting differentiation of pro-inflammatory effector Th1/Th17 CD4⁺ T cell. Mechanistically, increased expression of KDM6B (JMJD3) histone demethylase, an antagonist of the polycomb repressive complex 2, underlies lineage-specific changes of T cell phenotypes associated with abrogation of BMPR1α signaling. These results reveal that BMPs are immunoregulatory cytokines mediating maturation and stability of peripheral FOXP3⁺ regulatory T cells (T_reg cells) and controlling generation of iT_reg cells. Thus, we establish that BMPs, a large cytokine family, are an essential link between stromal tissues and the adaptive immune system involved in sustaining tissue homeostasis by promoting immunological tolerance.

Differential effects of Huaier aqueous extract on human CD4+T lymphocytes from patients with primary immune thrombocytopenia

Huaier, a traditional Chinese medicine, is currently used to treat certain types of cancer in the clinic and is also regarded as an immune-modulating and immune-enhancing agent that regulates immune cells. Emerging evidence indicates that an imbalance of immune cells, such as CD4⁺ T helper (Th) lymphocytes, contributes to the progression of immune thrombocytopenia (ITP), but the effects of Huaier on the regulation of CD4⁺ T cells are not yet fully elucidated. In the present study, Jurkat cells and peripheral blood mononuclear cells (PBMCs) from patients with ITP and healthy volunteers were treated with Huaier aqueous extract (HR). The CCK-8 assay revealed that HR suppressed the proliferation of Jurkat cells in a dose-dependent manner, whereas 3 mg/mL could decrease cell viability by 50%. At the latter concentration, the activation of CD4⁺ T cells from patients with ITP was partially attenuated. In addition, HR could correct the unbalanced Th1/Th2 polarization and inhibit the secretion of pro-inflammatory factors interleukin (IL)-2, tumor necrosis factor-α, and interferon-γ. It also suppressed Treg and facilitated Th17 differentiation, but did not change the levels of IL-10 and transforming growth factor-β. Thus, this study provides more information on how Huaier regulates cellular immunity and improves our understanding of the use of Huaier in ITP.

Transcriptional and posttranslational regulation of Th17/Treg balance in health and disease

Regulatory T (Treg) cells and T helper type 17 (Th17) cells play important roles in adaptive immune responses, antagonizing each other in immune disorders. Th17/Treg balance is critical to maintaining the immune homeostasis of human bodies and is tightly regulated under healthy conditions. The transcription factors that are required for driving Th17 and Treg cell lineages differentiation respectively, RORγt and FOXP3 are tightly regulated under different tissue microenvironment, especially the transcriptional induction, posttranslational modifications, and dynamic enzymatic cofactors binding. The imbalance caused by alteration of the quantity or properties of RORγt⁺ Th17 or FOXP3⁺ Treg can contribute to inflammatory disorders in humans. Restoring Th17/Treg balance by modifying the enzymatic activities of RORγt and FOXP3 binding partners may be therapeutically applied to treat severe immune disorders. In this review, we focus on the transcriptional and posttranslational regulations of Th17/Treg balance, immune disorders caused by Th17/Treg imbalance, and new therapeutic strategies for restoring immune homeostasis.

Rosmarinic acid protects mice from imiquimod induced psoriasis-like skin lesions by inhibiting the IL-23/Th17 axis via regulating Jak2/Stat3 signaling pathway

IL-23/Th17 (IL-17) axis plays a critical role in psoriasis. Rosmarinic acid (RA) was proved the inhibitory effect of T cell infiltration in the skin. However, whether and how RA has beneficial effects on psoriasis did not really know yet. So lipopolysaccharide (LPS)-induced abnormal proliferation Hacat cell line and Imiquimod (IMQ)-induced psoriasis-like mouse dermatitis were used to assess the pharmacological effects and mechanisms of RA by Psoriasis Area Severity Index (PASI) score, histopathology, flow cytometry, reverse transcription-polymerase chain reaction (RT-PCR) and western blotting. The results showed that RA inhibited LPS-induced aberrant expression of Hacat cell line, and significantly alleviated IMQ-induced skin inflammation. Although RA had no obviously effect on the ratio of epidermal Langerhans cell (LC) and LC migration from the skin to the skin draining lymph nodes, RA inhibited the expression of IL-23 in skin lesions, as well as reduced the differentiation of Th17 cells and producing of IL-17A by down regulating the transcriptor factor RORγt and JAK2/Stat3 signal pathway, comparing to IMQ treated group. The findings suggest that RA inhibits psoriasis-like skin inflammation in vivo and in vitro by reducing the expression of IL-23, inhibiting Th17 dominated inflammation and down regulating the Jak2/Stat3 signal pathway.

Key molecules involved in the Th17/Treg balance are associated with the pathogenesis of reflux esophagitis and Barrett's esophagus

BACKGROUND

Reflux esophagitis (RE) impairs the squamous epithelium that normally lines the esophagus, and contributes to the replacement of the damaged squamous lining by the intestinal metaplasia of Barrett's esophagus (BE), which is considered as a precursor of esophageal adenocarcinoma. This study aimed to investigate the changes in the balance of Th17/Treg and the related key molecules in the pathogenesis of RE and BE and evaluate the diagnostic and predictive value of the molecules in patients with these diseases.

METHODS

The proportions of Th17 and Treg in RE and BE patients were estimated using flow cytometric analysis. Key molecules involving in the Th17/Treg balance, including RORγt, Foxp3, IL-17, IL-6, IL-10, and TGF-β, were measured using quantitative real-time PCR (qRT-PCR) and ELISA analyses. The diagnostic and predictive value of the Th17/Treg ratio and its key regulators was evaluated using a receiver operating characteristic assay (ROC). In addition, the Spearman correlation analysis explored the relationship between the Th17/Treg ratio and the clinical characteristics.

RESULTS

An increased ratio of Th17/Treg was observed in RE and BE compared with the normal controls, and the proportion of Th17/Treg in BE was further increased compared with RE patients. Moreover, the expression levels of RORγt, IL-17, IL-6, and TGF-β were elevated, while the levels of Foxp3 and IL-10 were reduced in patients when compared to the controls. Compared with the RE groups, the levels of IL-17 were significantly higher in BE patients, while the Foxp3 levels were significant decreased. In addition, the Th17/Treg ratio also showed high diagnostic significance and considerable predictive value for the clinical outcomes in patients with RE and BE.

CONCLUSION

The balance of Th17/Treg was impaired in patients with RE and BE. Th17/Treg may be involved in the development of both RE and BE through regulating the release of inflammatory cytokines, but the concrete mechanisms maybe different in the two diseases. The imbalance of Th17/Treg ratio and the related key molecules had a certain clinical diagnosis and prediction potential for RE and BE.

Baicalin Ameliorates Inflammatory Response in a Mouse Model of Rhinosinusitis via Regulating the Treg/Th17 Balance

OBJECTIVE

Rhinosinusitis is a global health problem affecting millions of people around the world. Baicalin is a bioactive compound isolated from medicinal plant Scutellaria baicalensis Georgi. The present study aims to investigate potential effects of baicalin on clinicopathological changes in nasal/sinus mucosa in a mouse model.

METHODS

A mouse model of sinonasal inflammation induced by high dose of ovalbumin was applied to evaluate effects of baicalin. Rhinosinusitis symptoms, histopathological features, levels of histamine, immunoglobulin E (IgE), IL-17A, IL-10, and balance of regulatory T cell (Treg)/T-helper 17 (Th17) responses were examined.

RESULTS

Baicalin significantly relieved rhinosinusitis symptoms in mice, reduced histopathological changes, and suppressed serum levels of histamine and IgE in a dose-dependent manner. In lymphocytes of mice, baicalin modulated balance of Treg/Th17 proportions by attenuating Th17 cells and enhancing Treg cells, respectively. The serum IL-17A was decreased and IL-10 was increased in mice treated by baicalin. In addition, baicalin promoted levels of Smad protein 3 (p-Smad3) and forkhead box P3 (FOXP3) to promote Treg cells while suppressed levels of p-Stat3 and retineic-acid-receptor-related orphan nuclear receptor γt (RORγt) to inhibit Th17 cells.

CONCLUSIONS

These data demonstrate that baicalin effectively ameliorates sinonasal inflammation in a mouse model by recovering the immunological balance of Treg/Th17 responses. Our finding highlights the potential value of baicalin for the treatment of rhinosinusitis.

Regulation of mRNA stability by RBPs and noncoding RNAs contributing to the pathogenicity of Th17 cells

Th17 cells remain one of the most important subsets of T cells in numerous autoimmune and chronic inflammatory diseases. Posttranscriptional regulation (PTR), especially mRNA stability, has recently emerged as an important mechanism that controls the fate of Th17 cells. This review summarizes the current knowledge on RNA-binding proteins (RBPs), microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) that induce mRNA stability changes and their roles in mediating the differentiation, proliferation, function, and migration of Th17 cells. In addition, we summarize the role of RNA modifications and nonsense-mediated mRNA decay (NMD) in Th17 cells. Ongoing research will help to identify practical applications for the regulation of mRNA stability and provide potential targets to prevent and treat Th17-related autoimmune diseases.

Th17/Treg Imbalance and Atherosclerosis

Atherosclerosis is nowadays recognized as a chronic inflammatory disease of large arteries. In recent years, cellular and molecular biology studies on atherosclerosis confirmed that the occurrence and development are related to inflammation and autoimmunity. A variety of immune cells, cytokines, and transcription factors are involved in this process. Current studies found that T helper cell 17, regulatory T cells, and their cytokines play an important role in the development of atherosclerosis and vulnerable plaque rupture. Here, we provide a review of the up-to-date applications of T helper cell 17, regulatory T cells, cytokines, and their balance in the prognosis and therapy of atherosclerosis.

Mechanisms behind the Immunoregulatory Dialogue between Mesenchymal Stem Cells and Th17 Cells

Mesenchymal stem cells (MSCs) exhibit potent immunoregulatory abilities by interacting with cells of the adaptive and innate immune system. In vitro, MSCs inhibit the differentiation of T cells into T helper 17 (Th17) cells and repress their proliferation. In vivo, the administration of MSCs to treat various experimental inflammatory and autoimmune diseases, such as rheumatoid arthritis, type 1 diabetes, multiple sclerosis, systemic lupus erythematosus, and bowel disease showed promising therapeutic results. These therapeutic properties mediated by MSCs are associated with an attenuated immune response characterized by a reduced frequency of Th17 cells and the generation of regulatory T cells. In this manuscript, we review how MSC and Th17 cells interact, communicate, and exchange information through different ways such as cell-to-cell contact, secretion of soluble factors, and organelle transfer. Moreover, we discuss the consequences of this dynamic dialogue between MSC and Th17 well described by their phenotypic and functional plasticity.

Effects of hypoxic exposure on immune responses of intestinal mucosa to Citrobacter colitis in mice

OBJECTIVE

The pathogenesis and mechanism of colitis may be related to intestinal flora, genetic susceptibility, environmental and immune factors. Among these various factors, the importance of environmental factors in the pathogenesis of colitis has been increasingly recognized. The purpose of this study was to investigate the effects of hypoxia on intestinal mucosal immunity.

METHODS

Experimental colitis was induced by oral gavage of Citrobacter rodentium (C. rodentium) in mice, then divided into normoxia group and hypoxia group. Mice were sacrificed after 2 weeks. Physiological and blood biochemical indicators were monitored to verify the hypoxia model. The body weight, fecal bacterial output, colon length and colon histopathology were observed to evaluate severity of colitis. The concentration of cytokines in colonic tissues were detected by ELISA. The percentage of CD4⁺ IFN-γ⁺ (Th1) and CD4⁺ IL-17⁺ (Th17) cells in mesenteric lymph nodes (MLN) were detected by flow cytometry. The levels of mucosal antimicrobial peptides (AMPs), related inflammatory factors and transcription factors in colon tissues were detected by qRT-PCR.

RESULTS

Mice in hypoxic C. rodentium infection (Hypoxia + C.r.) group exhibited significant decrease in body weight, increase in fecal bacterial pathogen output, and more severe histopathological damage in the colon compared with the C. rodentium infection (Nomoxia + C.r.) group. Meanwhile, the level of NF-κB, TLR4, COX-2, IL-6 and TNF-α of colonic tissue were increased, while IL17, IL-22, and Reg3γ were decreased. The percentage of CD4⁺ IFN-γ⁺ (Th1) and CD4⁺ IL-17⁺ (Th17) cells in MLN were significantly decreased in mice of Hypoxia + C.r. group, accompanied by the decreased of IFN-γ and IL-17. In addition, the level of the T-bet, RORγt, IL-12 and IL-23 were decreased in mice of Hypoxia + C.r. group.

CONCLUSIONS

Hypoxic exposure significantly exacerbates the symptoms and the pathological damage of mice with colitis and influences the immune function by down-regulating Th1 and Th17 responses in C. rodentium-induced colitis in mice.

Recombinant adiponectin alleviates abortion in mice by regulating Th17/Treg imbalance via p38MAPK-STAT5 pathway

Recurrent spontaneous abortion is associated with abnormal maternal tolerance to the semi-allogenic fetus, wherein the Th17/Treg axis plays a crucial role. Adiponectin (APN) is an adipocytokine that is shown to be a novel negative T-cell regulator and induce immune tolerance. The CBA/J × DBA/2 mating was used as an abortion-prone model to investigate whether the addition of recombinant adiponectin (rAPN) improves the pregnancy outcome. Recombinant adiponectin therapy reduced the abortion rate in abortion-prone model. It skewed the ability of serum cytokine production toward a Treg bias and induced APN production. Flow cytometry revealed that rAPN administration expanded the splenic CD4+CD25+ regulatory T-cell (Treg) population and reduced the Th17 cell populations in CBA/J × DBA/2 matings. RT-PCR revealed that rAPN administration induced the expression of AdipoR1 and AdipoR2 mRNA at the maternofetal interface. Recombinant adiponectin administration induced FoxP3 and reduced RORγt expressions at the maternofetal interface. In vitro experiment also showed that rAPN treatment enhanced the FoxP3 mRNA and protein expression and decreased the RORγt expression in splenic lymphocytes of abortion-prone mice. Blocking the different signal transduction pathways downstream of APN, p38MAPK inhibitor (SB203580) and STAT5 inhibitor (Pimozide) could abrogate the regulatory effect of rAPN on FoxP3 and RORγt expression, while STAT3 inhibitor (Stattic) and AMPK inhibitor (p5499) did not exert any influence. Thus, the current results demonstrated that rAPN therapy improves pregnancy outcome in a murine model of abortion by expanding the Treg cell population and function and decreasing the Th17 cell population and function via a p38MAPK-STAT5 pathway.

Transient Expression of IL-17A in Foxp3 Fate-Tracked Cells in Porphyromonas gingivalis-Mediated Oral Dysbiosis

In periodontitis Porphyromonas gingivalis contributes to the development of a dysbiotic oral microbiome. This altered ecosystem elicits a diverse innate and adaptive immune response that simultaneously involves Th1, Th17, and Treg cells. It has been shown that Th17 cells can alter their gene expression to produce interferon-gamma (IFN-γ). Forkhead box P3 (Foxp3) is considered the master regulator of Treg cells that produce inhibitory cytokines like IL-10. Differentiation pathways that lead to Th17 and Treg cells from naïve progenitors are considered antagonistic. However, it has been reported that Treg cells expressing IL-17A as well as IFN-γ producing Th17 cells have been observed in several inflammatory conditions. Each scenario appears plausible with T cell transdifferentiation resulting from persistent microbial challenge and consequent inflammation. We established that oral colonization with P. gingivalis drives an initial IL-17A dominated Th17 response in the oral mucosa that is dependent on intraepithelial Langerhans cells (LCs). We hypothesized that Treg cells contribute to this initial IL-17A response through transient expression of IL-17A and that persistent mucosal colonization with P. gingivalis drives Th17 cells toward an IFN-γ phenotype at later stages of infection. We utilized fate-tracking mice where IL-17A- or Foxp3-promoter activity drives the permanent expression of red fluorescent protein tdTomato to test our hypothesis. At day 28 of infection timeline, Th17 cells dominated in the oral mucosa, outnumbering Th1 cells by 3:1. By day 48 this dominance was inverted with Th1 cells outnumbering Th17 cells by nearly 2:1. Tracking tdTomato⁺ Th17 cells revealed only sporadic transdifferentiation to an IFN-γ-producing phenotype by day 48; the appearance of Th1 cells at day 48 was due to a late de novo Th1 response. tdTomato⁺ Foxp3⁺ T cells were 35% of the total live CD4⁺T cells in the oral mucosa and 3.9% of them developed a transient IL-17A-producing phenotype by day 28. Interestingly, by day 48 these IL-17A-producing Foxp3⁺ T cells had disappeared. Therefore, persistent oral P. gingivalis infection stimulates an initial IL-17A-biased response led by Th17 cells and a small but significant number of IL-17A-expressing Treg cells that changes into a late de novo Th1 response with only sporadic transdifferentiation of Th17 cells.

A unique thymus-derived regulatory T cell subset associated with systemic lupus erythematosus

Background

Foxp3 is a marker for regulatory T cells (Treg cells), but recent studies have shown the plasticity and heterogeneity of CD4⁺Foxp3⁺ T cells. This study aimed to examine the phenotype and function of circulating CD4⁺Foxp3⁺ T cells in patients with systemic lupus erythematosus (SLE).

Methods

We enrolled 47 patients with SLE, 31 with organ-specific autoimmune diseases (15 with multiple sclerosis and 16 with primary immune thrombocytopenia), and 19 healthy subjects. Peripheral blood mononuclear cells were used to evaluate the proportion and phenotype of CD4⁺Foxp3⁺ cells using multicolor flow cytometry, the status of the Treg-specific demethylated region (TSDR) of the foxp3 gene by methylation-specific polymerase chain reaction, and the immunoregulatory function of CD4⁺CD25⁺ cells by allogeneic mixed lymphocyte reaction. Immunohistochemistry of renal biopsy specimens obtained from 6 patients with lupus nephritis and 5 with IgA nephropathy was conducted to detect IL-17A-expressing CD4⁺Foxp3⁺ cells.

Results

CD4⁺Foxp3⁺ T cells were increased in SLE patients compared with organ-specific autoimmune disease controls or healthy controls. Circulating CD4⁺Foxp3⁺ T cells were correlated with the disease activity of SLE. The increased CD4⁺Foxp3⁺ T cells in active SLE patients were mainly derived from thymus-derived Treg (tTreg) cells, as determined by a demethylated TSDR status, and represented a unique phenotype, upregulated expression of CD49d, CD161, and IL-17A, with immunosuppressive ability comparable to that of healthy controls. Finally, CD4⁺Foxp3⁺IL-17A⁺ cells were infiltrated into the renal biopsy specimens of patients with active lupus nephritis.

Conclusions

A unique tTreg subset with dichotomic immunoregulatory and T helper 17 phenotypes is increased in the circulation of SLE patients and may be involved in the pathogenic process of SLE.

Downregulation of miR-4772-3p promotes enhanced regulatory T cell capacity in malignant pleural effusion by elevating Helios levels

Background:

Malignant pleural effusion (MPE) is a complicated condition of patients with advanced tumors. Further dissecting the microenvironment of infiltrated immune cells and malignant cells are warranted to understand the immune-evasion mechanisms of tumor development and progression.

Methods:

The possible involvement of microRNAs (miRNAs) in malignant pleural fluid was investigated using small RNA sequencing. Regulatory T cell (Treg) markers (CD4, CD25, forkhead box P3), and Helios (also known as IKAROS Family Zinc Finger 2 [IKZF2]) were detected using flow cytometry. The expression levels of IKZF2 and miR-4772-3p were measured using quantitative real-time reverse transcription polymerase chain reaction. The interaction between miR-4772-3p and Helios was determined using dual-luciferase reporter assays. The effects of miR-4772-3p on Helios expression were evaluated using an in vitro system. Correlation assays between miR-4772-3p and functional molecules of Tregs were performed.

Results:

Compared with non-malignant controls, patients with non-small cell lung cancer had an increased Tregs frequency with Helios expression in the MPE and peripheral blood mononuclear cells. The verified downregulation of miR-4772-3p was inversely related to the Helios⁺ Tregs frequency and Helios expression in the MPE. Overexpression of miR-4772-3p could inhibit Helios expression in in vitro experiments. However, ectopic expression of Helios in induced Tregs reversed the effects induced by miR-4772-3p overexpression. Additionally, miR-4772-3p could regulate Helios expression by directly targeting IKZF2 mRNA.

Conclusion:

Downregulation of miR-4772-3p, by targeting Helios, contributes to enhanced Tregs activities in the MPE microenvironment.

CD200/CD200 receptor axis in psoriasis vulgaris

BACKGROUND

Psoriasis is a chronic inflammatory multisystem disease with imbalance between the Th17 and T regulatory sub-populations. CD200/CD200R is an anti-inflammatory/immune-suppressive axis that might contribute to its pathogenesis given its relation to the Tregs induction. The current study aimed to investigate the status of the CD200/CD200R axis in the blood of psoriasis vulgaris patients versus healthy controls.

METHODS

In this comparative cross sectional study, the blood levels of sCD200 and CD200R levels were measured in 25 psoriasis vulgaris patients and an age and sex matched 25 healthy controls using ELISA and flow-cytometry respectively. Their levels were tested for correlation to disease severity.

RESULTS

sCD200 was significantly higher while CD200R was significantly lower in psoriasis vulgaris patients than in controls. They did not correlate to each other or to psoriasis severity although they differed significantly among cases of different severities.

CONCLUSION

Aberrant expression of CD200/CD200R might play a role in psoriasis vulgaris pathophysiology and disease severity. It might constitute a future target of therapy, but cannot be used as a marker of disease severity.

LncRNA GAS5 inhibits Th17 differentiation and alleviates immune thrombocytopenia via promoting the ubiquitination of STAT3

BACKGROUND

The increased differentiation of T helper 17 cells (Th17) accelerates the development of immune thrombocytopenia (ITP), which is a common autoimmune disease with limited therapeutic methods. Recent studies have revealed that long non-coding RNAs (lncRNAs) play a critical role in autoimmune diseases, thus this study aims to investigate the effect of lncRNA GAS5 on the differentiation of Th17 cells in ITP.

METHODS

The expression of GAS5 in peripheral blood mononuclear cells (PBMCs) of ITP patients and spleen tissues of ITP mice was measured by qRT-PCR. The percentage of Th17 cells in CD4⁺ cells was measured by flow cytometry. The combination between GAS5 and STAT3 was confirmed by RNA pull-down assay and RNA Binding Protein Immunoprecipitation (RIP). The ubiquitination of STAT3 was detected by ubiquitination assay and the interaction between STAT3 and TRAF6 was measured by Co-Immunoprecipitation (Co-IP). Finally, the effect of GAS5 on Th17 differentiation was investigated in vitro and in vivo using lentivirus (lenti)-GAS5.

RESULTS

GAS5 expression was downregulated both in PBMCs of ITP patients and spleen tissues of ITP mice. Overexpression of GAS5 suppressed Th17 differentiation while had no effect on Treg differentiation in naïve CD4⁺ cells. RNA pull-down and RNA immunoprecipitation assays confirmed the interaction between GAS5 and STAT3. Further studies showed GAS5 accelerated the degradation of STAT3 via promoting TRAF6-mediated ubiquitination. Overexpressing GAS5 suppressed Th17 differentiation in vitro and alleviated ITP in vivo via reducing STAT3.

CONCLUSION

LncRNA GAS5 inhibited Th17 differentiation through promoting the TRAF6-mediated ubiquitination of STAT3, thus relieving ITP.

Molecular networks of FOXP family: dual biologic functions, interplay with other molecules and clinical implications in cancer progression

Though Forkhead box P (FOXP) transcription factors comprising of FOXP1, FOXP2, FOXP3 and FOXP4 are involved in the embryonic development, immune disorders and cancer progression, the underlying function of FOXP3 targeting CD4 + CD25+ regulatory T (Treg) cells and the dual roles of FOXP proteins as an oncogene or a tumor suppressor are unclear and controversial in cancers to date. Thus, the present review highlighted research history, dual roles of FOXP proteins as a tumor suppressor or an oncogene, their molecular networks with other proteins and noncoding RNAs, cellular immunotherapy targeting FOXP3, and clinical implications in cancer progression.

Isolation and enrichment of mouse insulin-specific CD4+ T regulatory cells

Polyclonal T regulatory cells (Treg - CD4⁺CD25⁺CD127^lowFoxp3⁺) are used in several protocols for the treatment of type 1 diabetes (T1D), multiple sclerosis and graft-versus host disease in clinical trials. However, general opinion is that autoantigen-specific Treg could be more efficient in autoimmunity suppression due to their direct effect on pathogenic autoantigen-specific effector T cells. This study describes isolation and expansion of insulin-specific Treg in vitro. Insulin-specific Treg are uniformly distributed in lymphoid tissues however their number is extremely low. To enrich the proportion of insulin-specific Treg, pure CD4⁺ cells were co-cultured with insulin B chain peptide-loaded dendritic cells, isolated from mice that develop T1D spontaneously - NOD mice. Insulin-specific CD4⁺ cell expansion peaked after 48 h of incubation and was in favour of Treg. These cells were then sorted using insulin peptide-loaded MHC class II tetramers and cultured in vitro for 48 h in the presence of TCR stimulators, TGF-β and IL-2. The proportion of gained insulin-specific cells with T regulatory phenotype (CD4⁺CD25^highCD127^lowGITR⁺FoxP3⁺) was in average between 93% and 97%. These cells have shown potent in vitro suppressive effect on T effector cells, produced IL-10 and TGF-β and expressed PD-1 and CD39. Further proliferation of these insulin-specific Treg required the presence of dendritic cells, anti-CD3 antibody and IL-2. This study provides new, reproducible experimental design for the enrichment and expansion of insulin-specific Treg that can be used for the cell-based therapy of autoimmunity.

The immunomodulatory mechanism of brain injury induced by hyperhomocysteinemia in spontaneously hypertensive rats

BACKGROUND

Elevated plasma homocysteine (Hcy) concentration is considered as the diagnostic criteria of Hyperhomocysteinemia (HHcy), which is associated with the inflammatory response and blood-brain barrier disruption. Previous studies have proposed that HHcy with hypertension was associated with the brain injury by enhancing the cerebrovascular permeability, however, the immune mechanism remains obscure. The purpose of the study is to explore the immunomodulatory mechanism of brain injury in spontaneously hypertensive rats (SHRs) induced by HHcy.

MATERIALS AND METHODS

Sixty SHRs were randomly assigned to three groups: SHR-C (control group), SHR-M (methionine group) and SHR-T (treatment group). Physical examination of body weight, systolic blood pressure (SBP) and plasma Hcy content was measured every 4 weeks. Besides, T-helper cell 17 and regulatory T cells (Treg)-related inflammatory cytokines (interleukin [IL]-6, IL-17, IL-10, and transforming growth factor beta [TGF-β]) and genes (RORγt and FoxP3) were detected by enzyme-linked immunosorbent assay, quantitative polymerase chain reaction , Western blot, and immunohistochemistry.

RESULTS

High methionine diet could cause weight loss, SBP rising, and plasma Hcy content significantly elevated. IL-16 and IL-17A levels in peripheral blood and in brain tissue both lifted, while IL-10 and TGF-β levels dropped; RORγt expression raised in brain, nevertheless, FoxP3 levels were the opposite. After the intervention with vitamin B6, B12, and folic acid in SHR-T group, these trends would be eased or completely changed. Furthermore, brain tissue slices showed that IL-17-positive cells tended to decrease, and IL-10-positive cells increased in SHR-T group, which was reversed in SHR-M group.

CONCLUSIONS

HHcy may promote inflammation that can lead to brain lesions and down-regulate immune response to protect the brain.

Fetal cord blood and tissue immune responses to chronic placental inflammation and chorioamnionitis

Background

Chorioamnionitis is a risk factor for future asthma development. Animal models of chorioamnionitis demonstrate increased T_H17-to-T_reg ratios associated with proinflammatory cytokine elevations. The association of chorioamnionitis on human neonatal immune cells systemically and within tissues is not known.

Methods

We enrolled two cohorts to evaluate T_H17 and regulatory T cell (T_reg) phenotypic markers in chorioamnionitis. From a cohort of 19 live birth infants, we collected cord blood and placenta samples to evaluate for signs of acute and chronic histologic inflammation and cell phenotype characterization. We analyzed a second cohort of stillborn infants with and without chorioamnionitis to classify and enumerate cell infiltrate phenotypes in the spleen, thymus, and lung. We used linear regression analysis determine the association of retinoic acid-related orphan receptor gamma t positive (RORγt⁺) and T_reg cell frequency with different types of inflammation seen in the live cohort subjects. Using linear mixed models, we evaluated for any associations between chorioamnionitis and T- and B-cell with a logarithmic scale for level of expression of cellular markers. We then performed Wilcoxon rank sum tests to assess the associations between cell count and chorioamnionitis.

Results

In the live birth subjects with chronic placental inflammation we observed an increased proportion of RORγt⁺ cells in Foxp3⁺ cells, regardless of the presence of acute inflammation, compared to subjects with neither acute nor chronic inflammation. We also found an increased proportion of RORγt⁺ cells within Foxp3⁺ cells in subjects with acute high stage fetal and maternal inflammation compared to those without acute or chronic inflammation. In the stillborn subjects with chorioamnionitis, we observed a decrease in splenic Foxp3⁺ cells and an increase in lung CD3⁺ cells compared with subjects that did not have chorioamnionitis.

Conclusion

Exposure to chorioamnionitis in utero may affect immune activation in neonates with an increased frequency of RORγt⁺ cells systemically as well as lymphocytic infiltrate in the lung. Our findings suggest an increase in RORγt⁺ cells during chorioamnionitis and thus may support the known associations between chorioamnionitis with asthma.

T helper 17 cell/regulatory T-cell imbalance in hidradenitis suppurativa/acne inversa: the link to hair follicle dissection, obesity, smoking and autoimmune comorbidities

BACKGROUND

Disintegration of the infundibula of terminal hair follicles (HFs) in intertriginous skin areas exhibits the histological hallmark of hidradenitis suppurativa (HS)/acne inversa, featuring a dissecting terminal hair folliculitis. Elevated serum levels of interleukin (IL)-17 and local increase in the ratio of proinflammatory T helper (Th)17 cells and anti-inflammatory regulatory T cells (Tregs) have been reported. Perifollicular Tregs play a key role in HF stem cell homeostasis and infundibular integrity.

OBJECTIVES

In this review, we evaluate the Th17/Treg ratio in HS, its aggravating conditions and associated comorbidities. Furthermore, we intended to clarify whether drugs with reported beneficial effects in the treatment of HS readjust the deviated Th17/Treg axis.

METHODS

PubMed-listed, peer-reviewed original research articles characterizing Th17/Treg regulation in HS/acne inversa and associated comorbidities were selected for this review.

RESULTS

This review presents HS as a disease that exhibits an increased Th17/Treg ratio. Perifollicular deficiencies in Treg numbers or function may disturb HF stem cell homeostasis, initiating infundibular dissection of terminal HFs and perifollicular inflammation. The Th17/Treg imbalance is aggravated by obesity, smoking and decreased Notch signalling. In addition, HS-associated autoimmune diseases exhibit a disturbed Th17/Treg axis resulting in a Th17-dominant state. All drugs that have beneficial effects in the treatment of HS normalize the Th17/Treg ratio.

CONCLUSIONS

HS immunopathogenesis is closely related to deviations of the Th17/Treg balance, which may negatively affect Treg-controlled HF stem cell homeostasis and infundibular integrity. Pharmacological intervention should not only attenuate Th17/IL-17 signalling, but should also improve Treg function in order to stabilize HF stem cell homeostasis and infundibular integrity.

The Balance of Th17 versus Treg Cells in Autoimmunity

T helper type 17 (Th17) cells and pTreg cells, which share a common precursor cell (the naïve CD4 T cell), require a common tumor growth factor (TGF)-β signal for initial differentiation. However, terminally differentiated cells fulfill opposite functions: Th17 cells cause autoimmunity and inflammation, whereas Treg cells inhibit these phenomena and maintain immune homeostasis. Thus, unraveling the mechanisms that affect the Th17/Treg cell balance is critical if we are to better understand autoimmunity and tolerance. Recent studies have identified many factors that influence this balance; these factors range from signaling pathways triggered by T cell receptors, costimulatory receptors, and cytokines, to various metabolic pathways and the intestinal microbiota. This review article summarizes recent advances in our understanding of the Th17/Treg balance and its implications with respect to autoimmune disease.