PTEN drives Th17 cell differentiation by preventing IL-2 production

Patients and mice with deficiency in the SNARE protein SYNTAXIN-11 have a secondary B cell defect

SYNTAXIN-11 (STX11) is a SNARE protein that mediates the fusion of cytotoxic granules with the plasma membrane at the immunological synapses of CD8 T or NK cells. Autosomal recessive inheritance of deleterious STX11 variants impairs cytotoxic granule exocytosis, causing familial hemophagocytic lymphohistiocytosis type 4 (FHL-4). In several FHL-4 patients, we also observed hypogammaglobulinemia, elevated frequencies of naive B cells, and increased double-negative DN2:DN1 B cell ratios, indicating a hitherto unrecognized role of STX11 in humoral immunity. Detailed analysis of Stx11-deficient mice revealed impaired CD4 T cell help for B cells, associated with disrupted germinal center formation, reduced isotype class switching, and low antibody avidity. Mechanistically, Stx11-/- CD4 T cells exhibit impaired membrane fusion leading to reduced CD107a and CD40L surface mobilization and diminished IL-2 and IL-10 secretion. Our findings highlight a critical role of STX11 in SNARE-mediated membrane trafficking and vesicle exocytosis in CD4 T cells, important for successful CD4 T cell-B cell interactions. Deficiency in STX11 impairs CD4 T cell-dependent B cell differentiation and humoral responses.

Interleukin-2 signaling in the regulation of T cell biology in autoimmunity and cancer

Interleukin-2 (IL-2) is a critical cytokine for T cell peripheral tolerance and immunity. Here, we review how IL-2 interaction with the high-affinity IL-2 receptor (IL-2R) supports the development and homeostasis of regulatory T cells and contributes to the differentiation of helper, cytotoxic, and memory T cells. A critical element for each T cell population is the expression of CD25 (Il2rα), which heightens the receptor affinity for IL-2. Signaling through the high-affinity IL-2R also reinvigorates CD8+ exhausted T (Tex) cells in response to checkpoint blockade. We consider the molecular underpinnings reflecting how IL-2R signaling impacts these various T cell subsets and the implications for enhancing IL-2-dependent immunotherapy of autoimmunity, other inflammatory disorders, and cancer.

STAT3 and SOX-5 induce BRG1-mediated chromatin remodeling of RORCE2 in Th17 cells

Retinoid-related orphan receptor gamma t (RORγt) is the lineage-specific transcription factor for T helper 17 (Th17) cells. Our previous study demonstrated that STAT3 likely participates in the activation of RORCE2 (a novel enhancer of the RORγt gene) in Th17 cells. However, the detailed mechanism is still unclear. Here, we demonstrate that both STAT3 and SOX-5 mediate the enhancer activity of RORCE2 in vitro. Deletion of the STAT3 binding site (STAT3-BS) in RORCE2 impaired RORγt expression and Th17 differentiation, resulting in reduced severity of experimental autoimmune encephalomyelitis (EAE). Mechanistically, STAT3 and SOX-5 bind the RORCE2 region and recruit the chromatin remodeling factor BRG1 to remodel the nucleosomes positioned at this region. Collectively, our data suggest that STAT3 and SOX-5 mediate the differentiation of Th17 cells through the induction of BRG1-mediated chromatin remodeling of RORCE2 in Th17 cells.

Human IL-17A protein production is controlled through a PIP5K1α-dependent translational checkpoint

The cytokine interleukin-17 (IL-17) is secreted by T helper 17 (TH17) cells and is beneficial for microbial control; however, it also causes inflammation and pathological tissue remodeling in autoimmunity. Hence, TH17 cell differentiation and IL-17 production must be tightly regulated, but, to date, this has been defined only in terms of transcriptional control. Phosphatidylinositols are second messengers produced during T cell activation that transduce signals from the T cell receptor (TCR) and costimulatory receptors at the plasma membrane. Here, we found that phosphatidylinositol 4,5-bisphosphate (PIP2) was enriched in the nuclei of human TH17 cells, which depended on the kinase PIP5K1α, and that inhibition of PIP5K1α impaired IL-17A production. In contrast, nuclear PIP2 enrichment was not observed in TH1 or TH2 cells, and these cells did not require PIP5K1α for cytokine production. In T cells from people with multiple sclerosis, IL-17 production elicited by myelin basic protein was blocked by PIP5K1α inhibition. IL-17 protein was affected without altering either the abundance or stability of IL17A mRNA in TH17 cells. Instead, analysis of PIP5K1α-associating proteins revealed that PIP5K1α interacted with ARS2, a nuclear cap-binding complex scaffold protein, to facilitate its binding to IL17A mRNA and subsequent IL-17A protein production. These findings highlight a transcription-independent, translation-dependent mechanism for regulating IL-17A protein production that might be relevant to other cytokines.

CD4+ T-cell subsets in autoimmune hepatitis: A review

Autoimmune hepatitis (AIH) is a chronic autoimmune liver disease that can lead to hepatocyte destruction, inflammation, liver fibrosis, cirrhosis, and liver failure. The diagnosis of AIH requires the identification of lymphoblast cell interface hepatitis and serum biochemical abnormalities, as well as the exclusion of related diseases. According to different specific autoantibodies, AIH can be divided into AIH-1 and AIH-2. The first-line treatment for AIH is a corticosteroid and azathioprine regimen, and patients with liver failure require liver transplantation. However, the long-term use of corticosteroids has obvious side effects, and patients are prone to relapse after drug withdrawal. Autoimmune diseases are characterized by an imbalance in immune tolerance of self-antigens, activation of autoreactive T cells, overactivity of B cells, and increased production of autoantibodies. CD4+ T cells are key players in adaptive immunity and can secrete cytokines, activate B cells to produce antibodies, and influence the cytotoxicity of CD8+ T cells. According to their characteristics, CD4+ T cells can be divided into different subsets. In this review, we discuss the changes in T helper (Th)1, Th2, Th17, Th9, Th22, regulatory T cell, T follicular helper, and T peripheral helper cells and their related factors in AIH and discuss the therapeutic potential of targeting CD4+ T-cell subsets in AIH.

Ivermectin Protects Against Experimental Autoimmune Encephalomyelitis in Mice by Modulating the Th17/Treg Balance Involved in the IL-2/STAT5 Pathway

Multiple sclerosis (MS), a T-cell-mediated autoimmune disease that affects the central nervous system (CNS), is characterized by white matter demyelination, axon destruction, and oligodendrocyte degeneration. Ivermectin, an anti-parasitic drug, has anti-inflammatory, anti-tumor, and antiviral properties. However, to date, there are no in-depth studies on the effect of ivermectin on the function effector of T cells in murine experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Here, we conducted in vitro experiments and found that ivermectin inhibited the proliferation of total T cells (CD3+) and their subsets (CD4+ and CD8+ T cells) as well as T cells secreting the pro-inflammatory cytokines IFN-γ and IL-17A; ivermectin also increased IL-2 production and IL-2Rα (CD25) expression, which was accompanied by an increase in the frequency of CD4+CD25+Foxp3+ regulatory T cells (Treg). Importantly, ivermectin administration reduced the clinical symptoms of EAE mice by preventing the infiltration of inflammatory cells into the CNS. Additional mechanisms showed that ivermectin promoted Treg cells while inhibiting pro-inflammatory Th1 and Th17 cells and their IFN-γ and IL-17 secretion; ivermectin also upregulated IL-2 production from MOG35-55-stimulated peripheral lymphocytes. Finally, ivermectin decreased IFN-γ and IL-17A production and increased IL-2 level, CD25 expression, and STAT5 phosphorylation in the CNS. These results reveal a previously unknown etiopathophysiological mechanism by which ivermectin attenuates the pathogenesis of EAE, indicating that it may be a promising option for T-cell-mediated autoimmune diseases such as MS.

Role of exosomes in the development of the immune microenvironment in hepatocellular carcinoma

Despite numerous improved treatment methods used in recent years, hepatocellular carcinoma (HCC) is still a disease with a high mortality rate. Many recent studies have shown that immunotherapy has great potential for cancer treatment. Exosomes play a significant role in negatively regulating the immune system in HCC. Understanding how these exosomes play a role in innate and adaptive immunity in HCC can significantly improve the immunotherapeutic effects on HCC. Further, engineered exosomes can deliver different drugs and RNA molecules to regulate the immune microenvironment of HCC by regulating the aforementioned immune pathway, thereby significantly improving the mortality rate of HCC. This study aimed to declare the role of exosomes in the development of the immune microenvironment in HCC and list engineered exosomes that could be used for clinical transformation therapy. These findings might be beneficial for clinical patients.

Ocimum sanctum L water extract: In-situ green synthesis of zinc oxide nanoparticles for treatment of rheumatoid arthritis: Preclinical study

BACKGROUND AND OBJECTIVE

Rheumatoid arthritis is a chronic progressive autoimmune disorder, characterised by destruction of cartilage and under line bones. Though exact etiology of rheumatoid arthritis (RA) remains unknown. It is believed that alteration in control of cellular or molecular responses is involved in the chronic inflammation. Earlier in RA patients it was observed the circulating RA specific biomarkers and immunoglobulin deposits in the synovial joints. Zinc Oxide Nanoparticles (ZnO NPs) is used as an anti-inflammatory and anticancer agent, however there is nil/very less scientific data shows the anti-arthritic activity of green synthesis ZnO nanoparticles (Ocimum sanctum water extract in-situ synthesis of ZnO NPs having active compound Caffeic acid and Rosmerinic acid). Hence, the present activity was planned to assess the anti-arthritic activity of ZnO NPs in CIA rats.

METHODS

Arthritis in rats were induced by subcutaneous injection of collagen type II (CII) (200 µl) at the base of tail on day 0 followed by booster dose on day 14. ZnO NPs were given (2 mg/kg b.wt./day) orally for 20 days. At the end of the study serum, joint homogenate was used to assess the level of biomarkers (RF, a-CCP, a-CII and CRP) and inflammatory mediators. In addition, m-RNA expression of various genes such as Nuclear factor-kB (NF-kB), inflammatory mediators like tumour necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2) etc. were assayed in joint tissue. Finally all these biochemical and molecular results were confirmed by microscopic study of joint tissue.

RESULTS

ZnO NPs, treated rats showed decrease in inflammation and clinical severity. This was related with decrease in the level of biomarkers (like RF, a-CCP and CRP), inflammatory mediators (TNF-α, COX-2) and activity of transcription factor NF-kB. All these findings were positively correlated with microscopic analysis of joint tissue that showed reduced inflammation and bone erosion in treated group.

CONCLUSION

This study validates the anti-arthritic activity of ZnO NPs as it mitigates the arthritis related symptoms in CIA rats.

Triptolide alleviates collagen-induced arthritis in mice by modulating Treg/Th17 imbalance through the JAK/PTEN-STAT3 pathway

BACKGROUND

This study aimed to investigate the effects of triptolide (TP) on collagen-induced arthritis (CIA) mice and the related mechanisms.

METHODS

CIA mice were administered TP for 35 days. Mouse ankle joints and serum antibodies and cytokines were examined to assess the therapeutic effects of TP. The ratios of Treg, Th1, and Th17 cells were measured by flow cytometry and RT-qPCR. Reverse docking was used to characterize the binding modes of TP against target proteins. The expression of the STAT3 pathway in CIA mice was evaluated by western blotting and immunofluorescence staining. Mouse spleen lymphocytes were extracted and the expression of the STAT3 pathway after IL-6 stimulation was analyzed.

RESULTS

TP could significantly alleviate joint swelling, reduce bone destruction, and downregulate serum inflammation levels. TP improved the imbalance of Treg/Th17 cells in CIA mice. TP could form stable complexes with target proteins. TP significantly inhibited the activation of the JAK/PTEN-STAT3 pathway in mice. Moreover, TP regulated the activation of the JAK1/2-STAT3 signaling pathway in mouse spleen lymphocytes under inflammatory stimulation.

CONCLUSION

TP can inhibit inflammation and alleviate bone destruction in CIA mice. The underlying mechanism is related to the regulation of the imbalance of Treg/Th17 cells through the JAK/PTEN-STAT3 pathway.

T cell receptor signaling in the differentiation and plasticity of CD4+ T cells

CD4⁺ T cells are critical components of the adaptive immune system. The T cell receptor (TCR) and co-receptor signaling cascades shape the phenotype and functions of CD4⁺ T cells. TCR signaling plays a crucial role in T cell development, antigen recognition, activation, and differentiation upon recognition of foreign- or auto-antigens. In specific autoimmune conditions, altered TCR repertoire is reported and can predispose autoimmunity with organ-specific inflammation and tissue damage. TCR signaling modulates various signaling cascades and regulates epigenetic and transcriptional regulation during homeostasis and disease conditions. Understanding the mechanism by which coreceptors and cytokine signals control the magnitude of TCR signal amplification will aid in developing therapeutic strategies to treat inflammation and autoimmune diseases. This review focuses on the role of the TCR signaling cascade and its components in the activation, differentiation, and plasticity of various CD4⁺ T cell subsets.

The PBX1/miR-141-miR-200a/EGR2/SOCS3 Axis; Integrative Analysis of Interaction Networks to Discover the Possible Mechanism of MiR-141 and MiR-200a-Mediated Th17 Cell Differentiation

Background

Overexpression of miR-141 and miR-200a is known to be associated with the differentiation of T helper 17 (Th17) cells, which are key players in the pathophysiology of autoimmune disorders. However, the function and governing mechanism of these two microRNAs (miRNAs) in Th17 cell skewing are poorly defined.

Objectives

The aim of the present study was to identify the common upstream transcription factors and downstream target genes of miR-141 and miR-200a to obtain a better insight into the possible dysregulated molecular regulatory networks driving miR-141/miR-200a-mediated Th17 cell development.

Materials and Methods

A consensus-based prediction strategy was applied for in-silico identification of potential transcription factors and putative gene targets of miR-141 and miR-200a. Thereafter, we analyzed the expression patterns of candidate transcription factors and target genes during human Th17 cell differentiation by quantitative real-time PCR and examined the direct interaction between both miRNAs and their potential target sequences using dual-luciferase reporter assays.

Results

According to our miRNA-based and gene-based interaction network analyses, pre-B cell leukemia homeobox (PBX1) and early growth response 2 (EGR2) were respectively taken into account as the potential upstream transcription factor and downstream target gene of miR-141 and miR-200a. There was a significant overexpression of the PBX1 gene during the Th17 cell induction period. Furthermore, both miRNAs could directly target EGR2 and inhibit its expression. As a downstream gene of EGR2, the suppressor of cytokine signaling 3 (SOCS3) was also downregulated during the differentiation process.

Conclusions

These results indicate that activation of the PBX1/miR-141-miR-200a/EGR2/SOCS3 axis may promote Th17 cell development and, therefore, trigger or exacerbate Th17-mediated autoimmunity.

Immune cells transcriptome-based drug repositioning for multiple sclerosis

Objective

Finding target genes and target pathways of existing drugs for drug repositioning in multiple sclerosis (MS) based on transcriptomic changes in MS immune cells.

Materials and Methods

Based on transcriptome data from Gene Expression Omnibus (GEO) database, differentially expressed genes (DEGs) in MS patients without treatment were identified by bioinformatics analysis according to the type of immune cells, as well as DEGs in MS patients before and after drug administration. Hub target genes of the drug for MS were analyzed by constructing the protein-protein interaction network, and candidate drugs targeting 2 or more hub target genes were obtained through the connectivity map (CMap) database and Drugbank database. Then, the enriched pathways of MS patients without treatment and the enriched pathways of MS patients before and after drug administration were intersected to obtain the target pathways of the drug for MS, and the candidate drugs targeting 2 or more target pathways were obtained through Kyoto Encyclopedia of Genes and Genomes (KEGG) database.

Results

We obtained 50 hub target genes for CD4⁺ T cells in Fingolimod for MS, 15 hub target genes for Plasmacytoid dendritic cells (pDCs) and 7 hub target genes for Peripheral blood mononuclear cells (PBMC) in interferon-β (IFN-β) for MS. 6 candidate drugs targeting two or more hub targets (Fostamatinib, Copper, Artenimol, Phenethyl isothiocyanate, Aspirin and Zinc) were obtained. In addition, we obtained 4 target pathways for CD19⁺ B cells and 15 target pathways for CD4⁺ T cells in Fingolimod for MS, 7 target pathways for pDCs and 6 target pathways for PBMC in IFN-β for MS, most of which belong to the immune system and viral infectious disease pathways. We obtained 69 candidate drugs targeting two target pathways.

Conclusion

We found that applying candidate drugs that target both the “PI3K-Akt signaling pathway” and “Chemokine signaling pathway” (e.g., Nemiralisib and Umbralisib) or applying tyrosine kinase inhibitors (e.g., Fostamatinib) may be potential therapies for the treatment of MS.

Opposing functions of circadian protein DBP and atypical E2F family E2F8 in anti-tumor Th9 cell differentiation

Interleukin-9 (IL-9)-producing CD4⁺ T helper cells (Th9) have been implicated in allergy/asthma and anti-tumor immunity, yet molecular insights on their differentiation from activated T cells, driven by IL-4 and transforming growth factor-beta (TGF-β), is still lacking. Here we show opposing functions of two transcription factors, D-binding protein (DBP) and E2F8, in controlling Th9 differentiation. Specifically, TGF-β and IL-4 signaling induces phosphorylation of the serine 213 site in the linker region of the Smad3 (pSmad3L-Ser²¹³) via phosphorylated p38, which is necessary and sufficient for Il9 gene transcription. We identify DBP and E2F8 as an activator and repressor, respectively, for Il9 transcription by pSmad3L-Ser²¹³. Notably, Th9 cells with siRNA-mediated knockdown for Dbp or E2f8 promote and suppress tumor growth, respectively, in mouse tumor models. Importantly, DBP and E2F8 also exhibit opposing functions in regulating human TH9 differentiation in vitro. Thus, our data uncover a molecular mechanism of Smad3 linker region-mediated, opposing functions of DBP and E2F8 in Th9 differentiation.

Stat5-/- CD4+ T cells elicit anti-melanoma effect by CD4+ T cell remolding and Notch1 activation

Signal transducers and activators of transcription 5 (Stat5) is known to engage in regulating the differentiation and effector function of various subsets of T helper cells. However, how Stat5 regulates the antitumor activity of tumor-infiltrating CD4⁺ T cells is largely unknown. Here, we showed that mice with specific deletion of Stat5 in CD4⁺ T cells were less susceptible to developing subcutaneous and lung metastatic B16 melanoma with CD4⁺ tumor-infiltrating lymphocytes (TILs) remolding. Especially, we confirmed that Stat5-deficient CD4⁺ naïve T cells were prone to polarization of two subtypes of Th17 cells: IFN-γ⁺ and IFN-γ^- Th17 cells, which exhibited increased anti-melanoma activity through enhanced activation of Notch1 pathway compared with wild type Th17 cells. Our study therefore revealed a novel function of Stat5 in regulating tumor-specific Th17 cell differentiation and function in melanoma. This study also provided a new possibility for targeting Stat5 and other Th17-associated pathways to develop novel immunotherapies for melanoma patients.

Mesenchymal stromal cells-derived extracellular vesicles reprogramme macrophages in ARDS models through the miR-181a-5p-PTEN-pSTAT5-SOCS1 axis

RATIONALE

A better understanding of the mechanism of action of mesenchymal stromal cells (MSCs) and their extracellular vesicles (EVs) is needed to support their use as novel therapies for acute respiratory distress syndrome (ARDS). Macrophages are important mediators of ARDS inflammatory response. Suppressor of cytokine signalling (SOCS) proteins are key regulators of the macrophage phenotype switch. We therefore investigated whether SOCS proteins are involved in mediation of the MSC effect on human macrophage reprogramming.

METHODS

Human monocyte-derived macrophages (MDMs) were stimulated with lipopolysaccharide (LPS) or plasma samples from patients with ARDS (these samples were previously classified into hypo-inflammatory and hyper-inflammatory phenotype) and treated with MSC conditioned medium (CM) or EVs. Protein expression was measured by Western blot. EV micro RNA (miRNA) content was determined by miRNA sequencing. In vivo: LPS-injured C57BL/6 mice were given EVs isolated from MSCs in which miR-181a had been silenced by miRNA inhibitor or overexpressed using miRNA mimic.

RESULTS

EVs were the key component of MSC CM responsible for anti-inflammatory modulation of human macrophages. EVs significantly reduced secretion of tumour necrosis factor-α and interleukin-8 by LPS-stimulated or ARDS plasma-stimulated MDMs and this was dependent on SOCS1. Transfer of miR-181a in EVs downregulated phosphatase and tensin homolog (PTEN) and subsequently activated phosphorylated signal transducer and activator of transcription 5 (pSTAT5) leading to upregulation of SOCS1 in macrophages. In vivo, EVs alleviated lung injury and upregulated pSTAT5 and SOCS1 expression in alveolar macrophages in a miR181-dependent manner. Overexpression of miR-181a in MSCs significantly enhanced therapeutic efficacy of EVs in this model.

CONCLUSION

miR-181a-PTEN-pSTAT5-SOCS1 axis is a novel pathway responsible for immunomodulatory effect of MSC EVs in ARDS.

A WWP2-PTEN-KLF5 signaling axis regulates odontoblast differentiation and dentinogenesis in mice

WW domain–containing E3 Ubiquitin-protein ligase 2 (WWP2) has been found to positively regulate odontoblastic differentiation by monoubiquitinating the transcription factor Kruppel-like factor 5 (KLF5) in a cell culture system. However, the in vivo role of WWP2 in mouse teeth remains unknown. To explore this, here we generated Wwp2 knockout (Wwp2 KO) mice. We found that molars in Wwp2 KO mice exhibited thinner dentin, widened predentin, and reduced numbers of dentinal tubules. In addition, expression of the odontoblast differentiation markers Dspp and Dmp1 was decreased in the odontoblast layers of Wwp2 KO mice. These findings demonstrate that WWP2 may facilitate odontoblast differentiation and dentinogenesis. Furthermore, we show for the first time that phosphatase and tensin homolog (PTEN), a tumor suppressor, is expressed in dental papilla cells and odontoblasts of mouse molars and acts as a negative regulator of odontoblastic differentiation. Further investigation indicated that PTEN is targeted by WWP2 for degradation during odontoblastic differentiation. We demonstrate PTEN physically interacts with and inhibits the transcriptional activity of KLF5 on Dspp and Dmp1. Finally, we found WWP2 was able to suppress the interaction between PTEN and KLF5, which diminished the inhibition effect of PTEN on KLF5. Taken together, this study confirms the essential role of WWP2 and the WWP2–PTEN–KLF5 signaling axis in odontoblast differentiation and dentinogenesis in vivo.

MicroRNA-22 Level in Patients with Multiple Sclerosis and Its Relationship with Vitamin D and Vitamin D Receptor Levels

INTRODUCTION

Multiple sclerosis (MS) is known to be a multifactorial disorder. Numerous observational studies have suggested the implication of multiple genetic and environmental factors in the pathogenesis of MS. The aim of this work was to evaluate expression of the microRNA-22 (miRNA-22) level, in relation to vitamin D (VD) and VD receptor (VDR) levels in patients with MS during remission state.

METHODS

This case-control study was conducted in 50 patients with clinically definite MS and 50 age- and sex-matched healthy controls. miRNA-22 expression was assessed in both MS patients and controls using quantitative RT-PCR. The serum level of VD and VDR was assessed in both MS patients and controls using ELISA techniques.

RESULTS

The miRNA-22 level was significantly downregulated in MS patients in comparison to controls (p value <0.001). MS patients had also significantly lower VD and VDR levels in comparison to controls (p value <0.001 and <0.001, respectively). Patients with secondary progressive MS (SPMS) have a significantly higher miRNA-22 level than patients with relapsing remitting MS (RRMS) (p value = 0.042). There was a statistically significant positive correlation between the miRNA-22 level and EDSS (p value = 0.033). There was also a statistically significant positive correlation between the miRNA-22 level and VDR level (p value = 0.002).

CONCLUSION

The miRNA-22 level was significantly downregulated in MS patients, but it had a positive correlation with disability status. Patients with SPMS have a significantly higher miRNA-22 level than patients with RRMS. VD and VDR levels were significantly lower in MS patients than controls. The miRNA-22 level was positively correlated with the VDR level.

Soluble interleukin-2 receptor as a predictive and prognostic marker for patients with familial breast cancer

The incidence of breast cancer increases annually, and it has become common within families of breast cancer patients. Interleukin-2 activates cytotoxic T lymphocytes, which are important for cancer immunity. To identify markers of increased familial breast cancer risk, soluble interleukin-2 receptor levels and immunologic factors were investigated in familial breast cancer and non-familial breast cancer patients. Of 106 untreated breast cancer patients in this study, 24 had familial breast cancer and 82 had non-familial breast cancer. The patients' soluble interleukin-2 receptor, interleukin-10, vascular endothelial growth factor, interleukin-17, regulatory T cell, myeloid-derived suppressor cell, white blood cell, and C-reactive protein levels, and their neutrophil-to-lymphocyte ratios were measured, and their prognoses were compared according to the soluble interleukin-2 receptor levels. Additionally, postoperative tissues from the patients with high soluble interleukin-2 receptor levels were stained with programmed cell death ligand 1 and cluster of differentiation 8. The soluble interleukin-2 receptor level in the familial breast cancer patients was significantly higher, and it showed significantly stronger correlations with the neutrophil-to-lymphocyte ratio and the interleukin-10, vascular endothelial growth factor, interleukin-17, regulatory T cell, myeloid-derived suppressor cell, white blood cell, and C-reactive protein levels, than in the non-familial breast cancer patients. The regulatory T cell and myeloid-derived suppressor cell levels were significantly higher in the patients with high soluble interleukin-2 receptor levels, and the overall survival and disease-free-survival rates were significantly worse for the familial breast cancer patients than for the non-familial breast cancer patients. Triple-negative breast cancer tissues from the familial breast cancer patients with high soluble interleukin-2 receptor levels stained well for programmed cell death ligand 1 and cluster of differentiation 8. Soluble interleukin-2 receptor levels can be used to predict the prognosis of familial breast cancer patients. Prospectively identifying patients who are less likely to have non-familial breast cancer is vital for improving their overall survival.

A critical role for Th17 cell-derived TGF-β1 in regulating the stability and pathogenicity of autoimmune Th17 cells

Pathogenic conversion of Th17 cells into multifunctional helper T cells or Th1 cells contributes to the pathogenesis of autoimmune diseases; however, the mechanism regulating the plasticity of Th17 cells remains unclear. Here, we found that Th17 cells expressed latent TGF-β1 in a manner dependent on autocrine TGF-β1. By employing IL-17-producing cell-specific Tgfb1 conditional knockout and fate-mapping systems, we demonstrated that TGF-β1-deficient Th17 cells are relatively susceptible to becoming IFN-γ producers through IL-12Rβ2 and IL-27Rα upregulation. TGF-β1-deficient Th17 cells exacerbated tissue inflammation compared to TGF-β1-sufficient Th17 cells in adoptive transfer models of experimental autoimmune encephalomyelitis and colitis. Thus, TGF-β1 production by Th17 cells provides an essential autocrine signal for maintaining the stability and regulating the pathogenicity of Th17 cells in vivo.

The Potential of Harnessing IL-2-Mediated Immunosuppression to Prevent Pathogenic B Cell Responses

Immunosuppressive drugs can partially control Antibody (Ab)-dependent pathology. However, these therapeutic regimens must be maintained for the patient's lifetime, which is often associated with severe side effects. As research advances, our understanding of the cellular and molecular mechanisms underlying the development and maintenance of auto-reactive B cell responses has significantly advanced. As a result, novel immunotherapies aimed to restore immune tolerance and prevent disease progression in autoimmune patients are underway. In this regard, encouraging results from clinical and preclinical studies demonstrate that subcutaneous administration of low-doses of recombinant Interleukin-2 (r-IL2) has potent immunosuppressive effects in patients with autoimmune pathologies. Although the exact mechanism by which IL-2 induces immunosuppression remains unclear, the clinical benefits of the current IL-2-based immunotherapies are attributed to its effect on bolstering T regulatory (Treg) cells, which are known to suppress overactive immune responses. In addition to Tregs, however, rIL-2 also directly prevent the T follicular helper cells (Tfh), T helper 17 cells (Th17), and Double Negative (DN) T cell responses, which play critical roles in the development of autoimmune disorders and have the ability to help pathogenic B cells. Here we discuss the broader effects of rIL-2 immunotherapy and the potential of combining rIL-2 with other cytokine-based therapies to more efficiently target Tfh cells, Th17, and DN T cells and subsequently inhibit auto-antibody (ab) production in autoimmune patients.

Insights into the mechanisms of Th17 differentiation and the Yin-Yang of Th17 cells in human diseases

Th17 cells are a lineage of CD4⁺ T helper cells with Th17-specific transcription factors RORγt and RoRα. Since its discovery in 2005, research on Th17 has been in rapid progress, and increasing cytokines or transcription factors have been uncovered in the activation and differentiation of Th17 cells. Furthermore, growing evidence proves there are two different subsets of Th17 cells, namely non-pathogenic Th17 (non-pTh17) and pathogenic Th17 (pTh17), both of which play important roles in adaptive immunity, especially in host defenses, autoimmune diseases, and cancer. In this review, we summarize and discuss the mechanisms of Th17 cells differentiation, and their roles in immunity and diseases.

Cytokines that Modulate the Differentiation of Th17 Cells in Autoimmune Uveitis

Increasing evidence has suggested that T helper 17 (Th17) cells play a central role in the pathogenesis of ocular immune disease. The association between pathogenic Th17 cells and the development of uveitis has been confirmed in experimental and clinical studies. Several cytokines affect the initiation and stabilization of the differentiation of Th17 cells. Therefore, understanding the mechanism of related cytokines in the differentiation of Th17 cells is important for exploring the pathogenesis and the potential therapeutic targets of uveitis. This article briefly describes the structures, mechanisms, and targeted drugs of cytokines-including interleukin (IL)-6, transforming growth factor-β1 (TGF-β1), IL-1β, IL-23, IL-27, IL-35, IL-2, IL-4, IL-21, and interferon (IFN)-γ-which have an important influence on the differentiation of Th17 cells and discusses their potential as therapeutic targets for treating autoimmune uveitis.

Si Miao San Attenuates Inflammation and Oxidative Stress in Rats with CIA via the Modulation of the Nrf2/ARE/PTEN Pathway

Objective

Si Miao San (SMS) is a traditional Chinese formula used in China to treat rheumatic diseases. To date, its mechanism in rheumatoid arthritis (RA) treatment is uncertain. Our study aims to assess the antiarthritic effects of SMS in experimental arthritic rats.

Materials and Methods

SMS (8.63, 4.31, and 2.16 g/kg/day) was orally administered after the first immunization from day 14 to day 53. The effects of SMS on rats with collagen-induced arthritis (CIA) were evaluated by arthritis score and histological assessment. The levels of cytokines and anti-CII antibodies in rat serum were measured by ELISAs. The expression of oxidative stress parameters was detected by biochemical assay kits. The levels of Nrf2, HO-1, NQO1, and PTEN were determined by western blotting.

Results

Medium- and high-dose SMS treatment significantly decreased arthritis scores and alleviated ankle joint histopathology in the rats with CIA. It inhibited the production of IL-6, TNF-α, COX-2, and PGE2 in rat serum. SMS also suppressed the expression of anti-CII antibodies IgG1 and IgG2a. Moreover, SMS significantly suppressed the levels of MDA and MPO in the synovial tissues while increasing the levels of SOD and CAT in the rats with CIA. The levels of Nrf2, HO-1, NQO1, and PTEN were upregulated by SMS in rat synovial tissues.

Conclusions

This study demonstrated that SMS effectively alleviated the disease progression of CIA by decreasing the levels of proinflammatory cytokines and reducing oxidative stress damage, as indicated by IL-6, TNF-α, COX-2, and PGE2 levels; inhibiting the overproduction of MDA and MPO; and enhancing antioxidant enzymes by upregulating the Nrf2/ARE/PTEN signalling pathway.

SOX-5 activates a novel RORγt enhancer to facilitate experimental autoimmune encephalomyelitis by promoting Th17 cell differentiation

T helper type 17 (Th17) cells have important functions in the pathogenesis of inflammatory and autoimmune diseases. Retinoid-related orphan receptor-γt (RORγt) is necessary for Th17 cell differentiation and functions. However, the transcriptional regulation of RORγt expression, especially at the enhancer level, is still poorly understood. Here we identify a novel enhancer of RORγt gene in Th17 cells, RORCE2. RORCE2 deficiency suppresses RORγt expression and Th17 differentiation, leading to reduced severity of experimental autoimmune encephalomyelitis. Mechanistically, RORCE2 is looped to RORγt promoter through SRY-box transcription factor 5 (SOX-5) in Th17 cells, and the loss of SOX-5 binding site in RORCE abolishes RORCE2 function and affects the binding of signal transducer and activator of transcription 3 (STAT3) to the RORγt locus. Taken together, our data highlight a molecular mechanism for the regulation of Th17 differentiation and functions, which may represent a new intervening clue for Th17-related diseases.

The Function and Role of the Th17/Treg Cell Balance in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic, inflammatory, and autoimmune disorder. The pathogenesis of IBD is not yet clear. Studies have shown that the imbalance between T helper 17 (Th17) and regulatory T (Treg) cells, which differentiate from CD4⁺ T cells, contributes to IBD. Th17 cells promote tissue inflammation, and Treg cells suppress autoimmunity in IBD. Therefore, Th17/Treg cell balance is crucial. Some regulatory factors affecting the production and maintenance of these cells are also important for the proper regulation of the Th17/Treg balance; these factors include T cell receptor (TCR) signaling, costimulatory signals, cytokine signaling, bile acid metabolites, and the intestinal microbiota. This article focuses on our understanding of the function and role of the balance between Th17/Treg cells in IBD and these regulatory factors and their clinical significance in IBD.

Present and Future of Anti-Glioblastoma Therapies: A Deep Look into Molecular Dependencies/Features

Glioblastoma (GBM) is aggressive malignant tumor residing within the central nervous system. Although the standard treatment options, consisting of surgical resection followed by combined radiochemotherapy, have long been established for patients with GBM, the prognosis is still poor. Despite recent advances in diagnosis, surgical techniques, and therapeutic approaches, the increased patient survival after such interventions is still sub-optimal. The unique characteristics of GBM, including highly infiltrative nature, hard-to-access location (mainly due to the existence of the blood brain barrier), frequent and rapid recurrence, and multiple drug resistance mechanisms, pose challenges to the development of an effective treatment. To overcome current limitations on GBM therapy and devise ideal therapeutic strategies, efforts should focus on an improved molecular understanding of GBM pathogenesis. In this review, we summarize the molecular basis for the development and progression of GBM as well as some emerging therapeutic approaches.

Interleukin-17 in Chronic Inflammatory Neurological Diseases

A critical role for IL-17, a cytokine produced by T helper 17 (Th17) cells, has been indicated in the pathogenesis of chronic inflammatory and autoimmune diseases. A positive effect of blockade of IL-17 secreted by autoreactive T cells has been shown in various inflammatory diseases. Several cytokines, whose production is affected by environmental factors, control Th17 differentiation and its maintenance in tissues during chronic inflammation. The roles of IL-17 in the pathogenesis of chronic neuroinflammatory conditions, multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE), Alzheimer's disease, and ischemic brain injury are reviewed here. The role of environmental stimuli in Th17 differentiation is also summarized, highlighting the role of viral infection in the regulation of pathogenic T helper cells in EAE.

IKZF3/Aiolos Is Associated with but Not Sufficient for the Expression of IL-10 by CD4+ T Cells

The expression of anti-inflammatory IL-10 by CD4+ T cells is indispensable for immune homeostasis, as it allows T cells to moderate their effector function. We previously showed that TNF-α blockade during T cell stimulation in CD4+ T cell/monocyte cocultures resulted in maintenance of IL-10-producing T cells and identified IKZF3 as a putative regulator of IL-10. In this study, we tested the hypothesis that IKZF3 is a transcriptional regulator of IL-10 using a human CD4+ T cell-only culture system. IL-10+ CD4+ T cells expressed the highest levels of IKZF3 both ex vivo and after activation compared with IL-10-CD4+ T cells. Pharmacological targeting of IKZF3 with the drug lenalidomide showed that IKZF3 is required for anti-CD3/CD28 mAb-mediated induction of IL-10 but is dispensable for ex vivo IL-10 expression. However, overexpression of IKZF3 was unable to upregulate IL-10 at the mRNA or protein level in CD4+ T cells and did not drive the transcription of the IL10 promoter or putative local enhancer constructs. Collectively, these data indicate that IKZF3 is associated with but not sufficient for IL-10 expression in CD4+ T cells.

PTEN negatively regulates the expression of pro-inflammatory cytokines and chemokines of fibroblast-like synoviocytes in adjuvant-induced arthritis

Rheumatoid arthritis (RA) is characterized by tumor-like expansion of the synovium and the subsequent destruction of adjacent articular cartilage and bone. The latest studies proved phosphatase and tension homolog deleted on chromosome 10 (PTEN) might contribute to the surviving, proliferation and pro-inflammatory cytokines in RA. The purpose of this study was to explore the function and underlying mechanisms of PTEN in RA pro-inflammatory cytokines and chemokines of fibroblast-like synoviocytes (FLSs). Increased level of PTEN was observed in adjuvant-induced arthritis (AIA) FLSs in comparison to normal rats. Increased concentrations of pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β), chemokines (CCL-2 and CCL-3), VCAM-1 and VEGF-α expression were observed in FLSs with PTEN inhibitor bpv or PTEN-RNAi. Moreover, co-incubation FLSs with overexpression vector with PTEN-GV141 reduced the expression of pro-inflammatory cytokines, chemokines, VCAM-1 and VEGF-α in AIA. Interestingly, we also found DNA methylation could regulate PTEN expression and activation of AKT signaling was with a change of PTEN. Altogether, our findings in the present study suggested that PTEN might play a pivotal role during pro-inflammatory cytokines and chemokines of FLSs through activation of AKT signaling pathway. In addition, PTEN expression may be regulated by DNA methylation in the pathogenesis of AIA.

Regulatory T cells and T helper 17 cells in viral infection

CD4⁺ T cells are the central element of the adaptive immune responses and protect the body from a variety of pathogens. Starting from naive cells, CD4⁺ T cells can differentiate into various effector cell subsets with specialized functions including T helper (Th) 1, Th2, Th17, regulatory T (Treg) and T follicular helper (Tfh) cells. Among them, Tregs and Th17 cells show a strong plasticity allowing the functional adaptation to various physiological and pathological environments during immune responses. Although they are derived from the same precursor cells and their differentiation pathways are interrelated, the terminally differentiated cells have totally opposite functions. Studies have shown that Tregs and Th17 cells have rather complex interplays in viral infection: Th17 cells may contribute to immune activation and disease progression while Tregs may inhibit this process and play a key role in the maintenance of immune homoeostasis, possibly at the cost of compromised viral control. In this review, we take respiratory syncytial virus (RSV), hepatitis B virus (HBV)/hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections as examples to discuss these interplays and their impacts on disease progression in viral infection.

The Role of PTEN in Innate and Adaptive Immunity

The lipid and protein phosphatase and tensin homolog (PTEN) controls the differentiation and activation of multiple immune cells. PTEN acts downstream from T- and B-cell receptors, costimulatory molecules, cytokine receptors, integrins, and also growth factor receptors. Loss of PTEN activity in human and mice is associated with cellular and humoral immune dysfunction, lymphoid hyperplasia, and autoimmunity. Although most patients with PTEN hamartoma tumor syndrome (PHTS) have no immunological symptoms, a subclinical immune dysfunction is present in many, and clinical immunodeficiency in few. Comparison of the immune phenotype caused by PTEN haploinsufficiency in PHTS, phosphoinositide 3-kinase (PI3K) gain-of-function in activated PI3K syndrome, and mice with conditional biallelic Pten deletion suggests a threshold model in which coordinated activity of several phosphatases control the PI3K signaling in a cell-type-specific manner. Emerging evidence highlights the role of PTEN in polygenic autoimmune disorders, infection, and the immunological response to cancer. Targeting the PI3K axis is an emerging therapeutic avenue.

Impact of simultaneous neutralization of IL-17A and treatment with recombinant IL-2 on Th17-Treg cell population in S.aureus induced septic arthritis

The contribution of Th17 and Treg in the pathogenesis of septic arthritis is well known. The imbalance of Th17/Treg ratio, especially the skewed CD4⁺ T cell differentiation towards pathogenic Th17 lineage is a major reason that mediates bone damage through one of its prime cytokine member IL-17A. The neutralization of released IL-17A, as well as exogenous administration of IL-2 at a lower dose, was seen to be potent in dampening the inflammatory response in many cases. Interestingly the effect of IL-17A neutralization to limit IL-17 mediated inflammation and induction of Tregs by the administration of IL-2 has not been studied in experimental arthritis. So in this study, we have treated arthritic mice with IL-17A Ab and recombinant mouse IL-2 either alone or in combination at 3, 9 and 15 days post-infection. We have found a marked decrease in Th17 cell population and their related pro-inflammatory cytokine levels at 15DPI in arthritic mice after IL-17 neutralization. An increased Treg cell population was also observed in mice after application of rIL-2 with a significantly heightened TGF-β level in serum and synovial joints compared to the untreated one. However, in the case of combination therapy of IL-17A Ab and rIL-2 we have observed a beneficial effect in ameliorating the disease outcome as the arthritic index was decreased maximally at 15DPI with a significant reduction of arthritis compared to individual treatment. Overall the inflammatory microenvironment was counterbalanced most effectively in combination treatment by lowering the Th17/Treg ratio and their related cytokines that resulted in reducing the immunopathogenesis of the destructive arthritis.

Cre-loxP Reporter Mouse Reveals Stochastic Activity of the Foxp3 Promoter

Mouse models that combine specific loxP-flanked gene sequences with Cre recombinase expressed from cell-regulated promoters have become important tools to investigate gene function. Critically however, expression of Cre recombinase may not always be restricted to the target cell or tissue of interest due to promiscuous activity of the driving promoter. Expression of Cre recombinase and, by extension, excision of the loxP-flanked gene may occur in non-target cells and may not be readily apparent. Here we report on the fidelity of Cre recombinase expressed from the il17a or Foxp3 promoters by combining them with a constitutively expressed floxed-stopped tdTomato reporter gene. Foxp3-driven Cre recombinase in F₁ mice induced tdTomato red fluorescent protein in Treg cells but also in a range of other immune cells. Frequency of tdTomato expression was variable but positively correlated (p < 0.0001) amongst lymphoid (B cells and CD8 T cells) and blood-resident myeloid cells (dendritic cells, monocytes, neutrophils) suggesting stochastic activity of the Foxp3 promoter rather than developmental regulation in common ancestral progenitors. Interestingly, frequency of tdTomato⁺ dendritic cells, monocytes and neutrophils did not correlate with the tdTomato⁺ fraction in eosinophils, indicating that activity of the Foxp3 promoter in eosinophils occurred after the split from a common multipotent progenitor. When these F₁ mice were crossed to achieve homozygosity of the promoter and reporter gene, a novel visually red phenotype was observed segregating amongst littermates. The red coloration was widespread and prevalent in non-immune tissues. Thymocytes examined from these red mice showed that all four subsets of immature thymocytes (CD4⁻ CD8⁻) based on differential expression of CD25 and CD44 were expressing tdTomato. Finally, we show evidence of Foxp3 Cre recombinase independent tdTomato expression, suggesting germ line transmission of an activated tdTomato reporter gene. Our data highlights potential issues with conclusions drawn from using specifically the B6.129(Cg)-Foxp3^{tm4(YFP/Cre)Ayr}/J mice.

Biology and regulation of IL-2: from molecular mechanisms to human therapy

IL-2 was first identified as a growth factor capable of driving the expansion of activated human T cell populations. In the more than 40 years since its discovery, a tremendous amount has been learned regarding the mechanisms that regulate the expression of both IL-2 and its cell surface receptor, its mechanisms of signalling and its range of biological actions. More recently, the mechanisms by which IL-2 regulates CD4⁺ T cell differentiation and function have been elucidated. IL-2 also regulates the effector and memory responses of CD8⁺ T cells, and the loss of IL-2 or responsiveness to IL-2 at least in part explains the exhausted phenotype that occurs during chronic viral infections and in tumour responses. These basic mechanistic studies have led to the therapeutic ability to manipulate the action of IL-2 on regulatory T (T_reg) cells for the treatment of autoimmune disease and on CD8⁺ T cells for immunotherapy of cancer. IL-2 can have either positive or deleterious effects, and we discuss here recent ideas and approaches for manipulating the actions and overall net effects of IL-2 in disease settings, including cancer.

The Alzheimer's Disease-Associated Protein BACE1 Modulates T Cell Activation and Th17 Function

β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) is best known for its role in Alzheimer's disease amyloid plaque formation but also contributes to neurodegenerative processes triggered by CNS injury. In this article, we report that BACE1 is expressed in murine CD4⁺ T cells and regulates signaling through the TCR. BACE1-deficient T cells have reduced IL-17A expression under Th17 conditions and reduced CD73 expression in Th17 and inducible T regulatory cells. However, induction of the Th17 and T regulatory transcription factors RORγt and Foxp3 was unaffected. BACE1-deficient T cells showed impaired pathogenic function in experimental autoimmune encephalomyelitis. These data identify BACE1 as a novel regulator of T cell signaling pathways that impact autoimmune inflammatory T cell function.

The transcription factor NFIL3 controls regulatory T-cell function and stability

Regulatory T (Treg) cells are a CD4 T-cell subset with an important role in immune tolerance; however, the mechanisms underlying Treg cell differentiation and function are incompletely understood. Here, we show that NFIL3/E4BP4, a transcription factor, plays a key role in Treg cell differentiation and function. Microarray analysis showed that Treg cells had lower Nfil3 expression than all other CD4 T-cell subsets. Overexpression of Nfil3 in Treg cells led to diminished expression of Foxp3 and other signature Treg genes, including Il2ra, Icos, Tnfrsf18, and Ctla4. Furthermore, Nfil3-overexpressing Treg cells exhibited impaired immunosuppressive activity in vitro and in vivo. We discovered that NFIL3 directly binds to and negatively regulates the expression of Foxp3. In addition, bisulfite sequencing revealed that NFIL3 induces methylation at Foxp3 locus regulatory CpG sites, which contributes to the control of Treg cell stability. Together, these data indicate that NFIL3 impairs Treg cell function through the downregulation of Foxp3 expression.

IL-23 and IL-1β Drive Human Th17 Cell Differentiation and Metabolic Reprogramming in Absence of CD28 Costimulation

Th17 cells drive autoimmune disease but also control commensal microbes. A common link among antigens from self-proteins or commensal microbiota is relatively low activation of T cell receptor (TCR) and costimulation signaling. Indeed, strong TCR/CD28 stimulation suppressed Th17 cell differentiation from human naive T cells, but not effector/memory cells. CD28 suppressed the classical Th17 transcriptional program, while inducing known Th17 regulators, and acted through an Akt-dependent mechanism. Th17 cells differentiated without CD28 were not anergic: they showed robust proliferation and maintained Th17 cytokine production following restimulation. Interleukin (IL)-23 and IL-1β promoted glucose uptake and increased glycolysis. Although modestly increased compared to CD28 costimulation, glycolysis was necessary to support Th17 differentiation, indicating that cytokine-mediated metabolic shifts were sufficient to obviate the classical requirement for CD28 in Th17 differentiation. Together, these data propose that, in humans, strength of TCR/CD28/Akt activation serves as a rheostat tuning the magnitude of Th17 development driven by IL-23 and IL-1β.

PTENtiating CFTR for Antimicrobial Immunity

Ivacaftor is a potentiator of the cystic fibrosis transmembrane conductance regulator (CFTR) that reduces Pseudomonas aeruginosa culture positivity in CF patients with unclear mechanisms. Riquelme et al. (2017) propose that improved CFTR trafficking could enhance P. aeruginosa clearance through activating the tumor suppressor PTEN.

The pathogenicity of Th17 cells in autoimmune diseases

IL-17-producing T helper (Th17) cells have been implicated in the pathogenesis of many inflammatory and autoimmune diseases. Targeting the effector cytokines IL-17 and GM-CSF secreted by autoimmune Th17 cells has been shown to be effective for the treatment of the diseases. Understanding a molecular basis of Th17 differentiation and effector functions is therefore critical for the regulation of the pathogenicity of tissue Th17 cells in chronic inflammation. Here, we discuss the roles of proinflammatory cytokines and environmental stimuli in the control of Th17 differentiation and chronic tissue inflammation by pathogenic Th17 cells in humans and in mouse models of autoimmune diseases. We also highlight recent advances in the regulation of pathogenic Th17 cells by gut microbiota and immunometabolism in autoimmune arthritis.

Factors involved in balance of Th17/Treg cells: Clinical implications in inflammatory bowel disease

T-helper 17 (Th17) cells promote tissue inflammation and T-regulatory (Treg) cells inhibit autoimmunity in inflammatory bowel disease (IBD). Thus, the balance between Th17 and Treg cells is crucial. Many factors that influence the generation and maintenance of these cells are also important for appropriate regulation of the Th17/Treg balance; these include TCR signals, costimulatory signals, cytokine signals, Foxp3 stability, metabolic processes, and the microbiota. This article will focus on what we know about these factors, their roles in regulating the Th17/Treg balance, and their clinical implications in IBD.

PTEN Hamartoma Tumor Syndrome and Immune Dysregulation

Carriers of a pathogenic germline mutations in the PTEN gene, a well-known tumor suppressor gene, are at increased risk of multiple benign and malignant tumors, e.g. breast, thyroid, endometrial and colon cancer. This is called PTEN Hamartomous Tumor Syndrome (PHTS). PHTS patients may also have an increased risk of immunological dysregulation, such as autoimmunity and immune deficiencies. The effects of PTEN on the immune system have been studied in murine knockout models demonstrating that loss of PTEN function leads to dysregulation of the immune response. This results in susceptibility to autoimmunity, impaired B cell class switching with subsequent hypogammaglobulinemia. Additionally, a decreased ability of dendritic cells to prime CD8⁺ T cells was observed, leading to impaired tumor eradication. Immune dysfunction in PHTS patients has not yet been extensively studied but might be a manageable contributing factor to the increased cancer risk in PHTS.

Th17 response in patients with cervical cancer

Persistent infection by high-risk human papillomavirus (HR-HPV) is the main risk factor for uterine cervical cancer (UCC). However, viral infection alone is not sufficient for the development and progression of premalignant cervical lesions for cancer. In previous years it has been suggested that the adaptive immune response triggered by the differentiation of naïve helper T cells in Th17 cells may serve an important role in disease development. It has been hypothesized that Th17 cells may be involved in the promotion of UCC, as high levels of interleukin 17 (IL17) expression have been detected in the mucosa of the uterine cervix of patients affected by the disease. However, the role of Th17 cells in the tumor development and progression remains unclear. It is believed that the immune response of the Th17 type during persistent infection of the genital tract with HR-HPV triggers chronic inflammation with a long duration with the production of IL17 and other pro-inflammatory cytokines, creating a favorable environment for tumor development. These cytokines are produced by immune system cells in addition to tumor cells and appear to function by modulating the host immune system, resulting in an immunosuppressive response as opposed to inducing an effective protective immune response, thus contributing to the growth and progression of the tumor. In the present review, the latest advances are presented about the function of Th17 cells and the cytokines produced by them in the development and progression of UCC.

Differential requirements for IRF4 in the clonal expansion and homeostatic proliferation of naive and memory murine CD8+ T cells

Interferon regulatory factor 4 (IRF4) has critical roles in immune cell differentiation and function and is indispensable for clonal expansion and effector function in T cells. Here, we demonstrate that the AKT pathway is impaired in murine CD8⁺ T cells lacking IRF4. The expression of phosphatase and tensin homolog (PTEN), a negative regulator of the AKT pathway, was elevated in Irf4^-/- CD8⁺ T cells. Inhibition of PTEN partially rescued downstream events, suggesting that PTEN constitutes a checkpoint in the IRF4-mediated regulation of cell signaling. Despite the clonal expansion defect, in the absence of IRF4, memory-like CD8⁺ T cells could be generated and maintained, although unable to expand in recall responses. The homeostatic proliferation of naïve Irf4^-/- CD8⁺ T cells was impaired, whereas their number eventually reached a level similar to that of wild-type CD8⁺ T cells. Conversely, memory-like Irf4^-/- CD8⁺ T cells underwent homeostatic proliferation in a manner similar to that of wild-type memory CD8⁺ T cells. These results suggest that IRF4 regulates the clonal expansion of CD8⁺ T cells at least in part via the AKT signaling pathway. Moreover, IRF4 regulates the homeostatic proliferation of naïve CD8⁺ T cells, whereas the maintenance of memory CD8⁺ T cells is IRF4-independent.

Aberrant T Cell Signaling and Subsets in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic multi-organ debilitating autoimmune disease, which mainly afflicts women in the reproductive years. A complex interaction of genetics, environmental factors and hormones result in the breakdown of immune tolerance to "self" leading to damage and destruction of multiple organs, such as the skin, joints, kidneys, heart and brain. Both innate and adaptive immune systems are critically involved in the misguided immune response against self-antigens. Dendritic cells, neutrophils, and innate lymphoid cells are important in initiating antigen presentation and propagating inflammation at lymphoid and peripheral tissue sites. Autoantibodies produced by B lymphocytes and immune complex deposition in vital organs contribute to tissue damage. T lymphocytes are increasingly being recognized as key contributors to disease pathogenesis. CD4 T follicular helper cells enable autoantibody production, inflammatory Th17 subsets promote inflammation, while defects in regulatory T cells lead to unchecked immune responses. A better understanding of the molecular defects including signaling events and gene regulation underlying the dysfunctional T cells in SLE is necessary to pave the path for better management, therapy, and perhaps prevention of this complex disease. In this review, we focus on the aberrations in T cell signaling in SLE and highlight therapeutic advances in this field.

When worlds collide: Th17 and Treg cells in cancer and autoimmunity

The balance between Th17 cells and regulatory T cells (Tregs) has emerged as a prominent factor in regulating autoimmunity and cancer. Th17 cells are vital for host defense against pathogens but have also been implicated in causing autoimmune disorders and cancer, though their role in carcinogenesis is less well understood. Tregs are required for self-tolerance and defense against autoimmunity and often correlate with cancer progression. This review addresses the importance of a functional homeostasis between these two subsets in health and the consequences of its disruption when these forces collide in disease. Importantly, we discuss the ability of Th17 cells to mediate cancer regression in immunotherapy, including adoptive transfer and checkpoint blockade therapy, and the therapeutic possibilities of purposefully offsetting the Th17/Treg balance to treat patients with cancer as well as those with autoimmune diseases.

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.