Regulates Th17 Differentiation Research Articles

Hederagenol improves multiple sclerosis by modulating Th17 cell differentiation.

Multiple sclerosis (MS) is a common autoimmune illness that is difficult to treat. The upregulation of Th17 cells is critical in the pathological process of MS. Hederagenol (Hed) has been shown to lower IL-17 levels, although its role in MS pathophysiology is uncertain. In this study, we explore whether Hed could ameliorate MS by modulating Th17 cell differentiation, with the goal of identifying new treatment targets for MS. The experimental autoimmune encephalomyelitis (EAE) mouse model was conducted and Hed was intraperitoneally injected into mice. The weight was recorded and the clinical symptom grade was assessed. Hematoxylin-eosin staining was carried out to determine the extent of inflammation in the spinal cord and liver. The luxol Fast Blue staining was performed to detect the pathological changes in the myelin sheath. Nerve damage was detected using NeuN immunofluorescence staining and terminal deoxynucleotidyl transferase dUTP nick-end labeling staining. Immunohistology approaches were used to study alterations in immune cells in the spinal cord. The proportions of T cell subsets in the spleens were analyzed by flow cytometry. RORγt levels were measured using quantitative real-time PCR or Western blot. The activity of the RORγt promoter was analyzed by Chromatin immunoprecipitation. Hed administration reduced the clinical symptom grade of EAE mice, as well as the inflammatory infiltration, demyelination, and cell disorder of the spinal cord, while having no discernible effect on the mouse weight. In addition, Hed treatment significantly reduced the number of T cells, particularly Th17 cells in the spinal cord and spleen-isolated CD4+ T cells. Hed lowered the RORγt levels in spleens and CD4+ T cells and overexpression of RORγt reversed the inhibitory effect of Hed on Th17 differentiation. Hed decreased nerve injury by modulating Th17 differentiation through the RORγt promoter. Hed regulates Th17 differentiation by reducing RORγt promoter activity, which reduces nerve injury and alleviates EAE.

Molecules in the hippo pathway that regulate Th17 differentiation reveal the severity of ankylosing spondylitis.

Ankylosing spondylitis (AS) is a chronic, progressive, and inflammatory autoimmune disease of unknown origin that affects the axial skeleton and sacroiliac joints, resulting in pain and loss of function. AS is characterized by the overdifferentiation of T helper 17 (Th17) cells, which contribute to the development of the disease. The Hippo signaling pathway is an important regulator of Th17 differentiation, but its role in patients with AS is unclear. We aimed to investigate the role of key molecules of the Hippo signaling pathway in inflammatory Th17 differentiation in patients with AS and to examine their correlation with disease stages. We examined the activity of the Hippo pathway in patients with AS and the regulation of Th17 differentiation during AS-mediated inflammation. Blood samples were collected from 60 patients with AS at various stages and 30 healthy controls. Peripheral blood mononuclear cells (PBMCs) were isolated from peripheral blood by density gradient centrifugation. The Serum Interleukin-17 (IL-17) levels in patients with AS and healthy controls were quantified by ELISA. The key molecules of Hippo pathway were assessed by real-time PCR for their mRNA expression, and protein levels were determined by Western blot analysis. Elevated serum interleukin-17 (IL-17) levels were observed in patients with AS compared with healthy controls. The protein and mRNA levels of retinoic acid receptor-related orphan receptor γt (RORγt), transcriptional coactivator with a PDZ-binding motif (TAZ), and key upstream transcription factors in the Hippo signaling pathway were measured. The expression of RORγt and TAZ was increased in the blood of patients with AS, whereas the expression of other Hippo pathway proteins, such as MST1/2 and NDR1/2, was significantly decreased. Increased levels of IL-17 and TAZ were significantly associated with disease activity. In addition, MST1, MST2, and NDR1 levels were negatively correlated with TAZ, RORγt, and IL-17 levels. Our findings suggest that the Hippo pathway plays a significant role in the regulation of Th17 differentiation and disease activity in patients with AS. The upregulation of TAZ and downregulation of key Hippo pathway proteins, such as MST1/2 and NDR1/2, may contribute to AS pathogenesis. These proteins may serve as biomarkers and may lead to the development of novel therapeutic strategies for AS.

SIRT3 Activator Honokiol Inhibits Th17 Cell Differentiation and Alleviates Colitis.

Honokiol (HKL), a natural extract of the bark of the magnolia tree and an activator of the mitochondrial protein sirtuin-3 (SIRT3), has been proposed to possess anti-inflammatory effects. This study investigated the inhibitory effects of HKL on T helper (Th) 17 cell differentiation in colitis. Serum and biopsies from 20 participants with ulcerative colitis (UC) and 18 healthy volunteers were collected for the test of serum cytokines, flow cytometry analysis (FACS), and relative messenger RNA (mRNA) levels of T cell subsets, as well as the expression of SIRT3 and phosphorylated signal transducer and activator of transcription/retinoic acid-related orphan nuclear receptor γt (p-STAT3/RORγt) signal pathway in colon tissues. In vitro, naïve clusters of differentiation (CD) 4 + T cells isolated from the mouse spleen differentiated to subsets including Th1, Th2, Th17, and regulatory T (Treg) cells. Peripheral blood monocytes (PBMCs) from healthy volunteers were induced to the polarization of Th17 cells. After HKL treatment, changes in T cell subsets, related cytokines, and transcription factors were measured. The dextran sulfate sodium (DSS)-induced colitis and interleukin (IL)-10-deficient mice were intraperitoneally injected with HKL. These experiments were conducted to study the effect of HKL on the development, cytokines, and expression of signaling pathway proteins in colitis. Patients with UC had higher serum IL-17 and a higher proportion of Th17 differentiation in blood compared with healthy participants; while IL-10 level and the proportion of Treg cells were lower. Higher relative mRNA levels of RORγt and a lower SIRT3 expression in colon tissues were observed. In vitro, HKL had little effect on the differentiation of naïve CD4+ T cells to Th1, Th2, or Treg cells, but it downregulated IL-17 levels and the Th17 cell ratio in CD4+ T cells from the mouse spleen and human PBMCs under Th17 polarization. Even with a STAT3 activator, HKL still significantly inhibited IL-17 levels. In DSS-induced colitis mice and IL-10 deficient mice treated with HKL, the length of the colon, weight loss, disease activity index, and histopathological scores were improved, IL-17 and IL-21 levels, and the proportion of Th17 cells were decreased. Sirtuin-3 expression was increased, whereas STAT3 phosphorylation and RORγt expression were inhibited in the colon tissue of mice after HKL treatment. Our study demonstrated that HKL could partially protect against colitis by regulating Th17 differentiation through activating SIRT3, leading to inhibition of the STAT3/RORγt signaling pathway. These results provide new insights into the protective effects of HKL against colitis and may facilitate the research of new drugs for inflammatory bowel disease.

HUC-MSCs Attenuate Acute Graft-Versus-Host Disease through Chi3l1 Repression of Th17 Differentiation.

Mesenchymal stem cells (MSCs) have already demonstrated definitive evidence of their clinical benefits in acute graft-versus-host disease (aGvHD) and other inflammatory diseases. However, the comprehensive mechanism of MSCs' immunomodulation properties has not been elucidated. To reveal their potential immunosuppressive molecules, we used RNA sequencing to analyze gene expression in different tissue-derived MSCs, including human bone marrow, umbilical cord, amniotic membrane, and placenta, and found that chitinase-3-like protein 1 (Chi3l1) was highly expressed in human umbilical cord mesenchymal stem cells (hUC-MSCs). We found that hUC-MSCs treated with interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) exhibited increased expression of Chi3l1 and concurrently repressed T-helper 17 cell (Th17) differentiation through inhibition of signal transducer and activator of transcription 3 (STAT3) activation. Furthermore, Chi3l1 knockdown hUC-MSCs exhibited impaired therapeutic efficacy in aGvHD mice with an increased inflammatory response by promoting Th17 cell differentiation, including an increase in IL-17A in the spleen, intestine, and serum. Collectively, these results reveal a new immunosuppressive molecule, Chi3l1, in hUC-MSCs in the treatment of aGvHD that regulates Th17 differentiation and inhibits STAT3 activation. These novel insights into the mechanisms of hUC-MSC immunoregulation may lead to the consistent production of hUC-MSCs with strong immunosuppressive functions and thus improved clinical utility.

JunB Is Critical for Survival of T Helper Cells.

Clonal expansion and differentiation of various T helper subsets, such as Th1, Th2, and Th17 cells, depend on a complex of transcription factors, IRF4 and a BATF-containing AP-1 heterodimer. A major BATF heterodimeric partner, JunB, regulates Th17 differentiation, but the role of JunB in other T helper subsets is not well understood. Here we demonstrate that JunB is required for clonal expansion of Th1, Th2 and Th17 cells. In mice immunized with lipopolysaccharide (LPS), papain, or complete Freund’s adjuvant (CFA), which induce predominantly Th1, Th2 and Th17 cells, respectively, accumulation of antigen-primed, Junb-deficient CD4+ T cells is significantly impaired. TCR-stimulated Junb-deficient CD4+ T cells are more sensitive to apoptosis, although they showed largely normal proliferation and cellular metabolism. JunB directly inhibits expression of genes involved in apoptosis, including Bcl2l11 (encoding Bim), by promoting IRF4 DNA binding at the gene locus. Taken together, JunB serves a critical function in clonal expansion of diverse T helper cells by inhibiting their apoptosis.

MiR-30a-centered molecular crosstalk regulates Th17 differentiation.

MiR-30a-centered molecular crosstalk regulates Th17 differentiation.

TREM-2 mediates dendritic cell-induced NO to suppress Th17 activation and ameliorate chronic kidney diseases.

Chronic kidney disease (CKD) is a global public health issue. CKD is caused by the infiltration of various myeloid cell types into renal tissue, resulting in renal fibrosis and tubular atrophy. Unilateral ureteral obstruction (UUO) surgery in mice is a model of CKD and characterized by high expression of the anti-inflammatory receptor, Triggering receptor expressed on myeloid cells 2 (TREM-2), on myeloid cells in affected kidneys. Here, we show that iNOS expression and nitric oxide (NO) induction were decreased in Trem-2-/- bone marrow-derived DCs (BMDCs) and in Trem-2 knockdown DC2.4 cells stimulated in vitro with LPS. The nitration of RORγt was decreased in T cells co-cultured with LPS-stimulated Trem-2-/- BMDCs, enhancing IL-17 production. UUO-treated Trem-2-/- mice displayed aggravated renal pathogenesis accompanied by greater neutrophil infiltration and enhanced Th17 cells differentiation, phenotypes that could be rescued by the administration of L-arginine (a biological precursor of NO). Our data identify a key mechanism underlying TREM-2-mediated NO to modulate the cellular crosstalk between dendritic cells, Th17, and neutrophils. Furthermore, we also reveal TREM-2 as a potential novel target for the development of anti-inflammatory drugs in CKD treatment. KEY MESSAGES: The expression of TREM-2 is increased in nephritis TREM-2+ DCs maintain NO production to negatively regulate Th17 differentiation The severe pathologies of nephritis can be rescued by L-arginine supplementation.

CELL-AUTONOMOUS HEDGEHOG SIGNALING CONTROLS TH17 DIFFERENTIATION TO DRIVE INTESTINAL INFLAMMATION AND IS A DRUGGABLE TARGET FOR THE TREATMENT OF INFLAMMATORY BOWEL DISEASE

Abstract BACKGROUND T helper 17 (Th17) cells play a key role in barrier protection in the gastrointestinal tract but are also key pathological drivers of Inflammatory Bowel Disease (IBD). Although a number of key transcription factors governing Th17 differentiation have been identified, the intracellular signaling pathways regulating Th17 differentiation are poorly understood. Given the highly druggable nature of many intracellular signaling pathways, understanding the signaling pathways involved in Th17 differentiation holds great promise to identify novel drug targets for the treatment of IBD. Hedgehog (Hh) signaling controls cell-fate choices in numerous tissue compartments and is targetable by highly selective, clinically-approved small molecule inhibitors. However the role of Hh signaling in Th17 differentiation and effector function is unstudied. METHODS We generated two conditional knockout mouse models targeting Hh signaling components Smo and Ihh to study Th17 differentiation and effector function in vitro and in vivo in murine T cell adoptive transfer colitis. We supplement this with the use of two small-molecule Smo antagonists for both in vitro and in vivo studies of Th17 function. To underscore the translational relevance of our findings, we have conducted bioinformatic analyses of published gene expression datasets of human rectal biopsies from two large independent cohorts of Ulcerative Colitis patients and healthy controls as well as from sorted human effector T cells from blood and lamina propria of healthy individuals. RESULTS We find that intracellular Hh signaling, independently of extracellular Hh ligands, selectively drives differentiation and effector function of Th17 cells but not of other T helper cell lineages. Using two models of intestinal inflammation, we demonstrate that inhibition of the Hh pathway with either the clinically-approved small molecule inhibitor vismodegib or genetic ablation of Ihh in CD4+ T cells profoundly diminishes disease severity and Th17-induced pathology in the intestine. Our bioinformatic analyses show that Hh component expression levels are upregulated in human ulcerative colitis patient samples and are closely correlated with expression of Th17 markers/cytokines. Mechanistically we show that the T-cell-intrinsic Indian Hedgehog (Ihh) ligand signals via the signal transducer Smoothened to activate both canonical and non-canonical Hh pathways, through the Gli3 transcription factor and AMPK phosphorylation, respectively. CONCLUSIONS We uncover Hh signaling as a novel pathway controlling Th17 differentiation and pathogenicity in IBD with Gli3 acting as a newly-identified crucial regulatory transcription factor. Our work paves the way for the use of Hh inhibitors for the treatment of IBD.

DOP48 Hedgehog signalling controls Th17 differentiation to drive intestinal inflammation and is a druggable target for the treatment of IBD

Abstract Background T helper 17 (Th17) cells play an important role in barrier protection in the gastrointestinal tract but are also key pathological drivers of Inflammatory Bowel Disease (IBD). Although a number of transcription factors governing Th17 differentiation have been identified, the intracellular signalling pathways regulating Th17 differentiation are poorly understood. Hedgehog (Hh) signalling controls cell-fate choices in numerous tissue compartments and is targetable by highly selective, clinically-approved small molecule inhibitors. However the role of Hh signalling in Th17 differentiation and effector function is unstudied. Methods We generated two conditional knockout mouse models targeting Hh signalling components Smo and Ihh to study Th17 differentiation in vitro by flow cytometry and gene expression analysis. For in vivo studies, T cell adoptive transfer colitis was performed using donor Ihh knockout T cells or heterozygote controls. Histological analysis, mouse weight, colon length/weight measurements, and flow cytometric analysis was performed. We supplement this with the use of two small-molecule Smo antagonists for in vitro and in vivo studies of Th17 function. To underscore the translational relevance of our findings, we conducted bioinformatic analyses of published gene expression datasets of human rectal biopsies from two large independent cohorts of Ulcerative Colitis patients and healthy controls. Results We find that intracellular Hh signalling, independently of extracellular Hh ligands, selectively drives differentiation and effector function of Th17 cells but not of other T helper cell lineages. We demonstrate in vivo that inhibition of the Hh pathway with either the clinically-approved small molecule inhibitor vismodegib or genetic ablation of Ihh in CD4+ T cells results in a significant decrease in histological and clinical readouts of disease severity as well as a significant reduction in IL-17a+ Th17 cells. Our bioinformatic analyses show that Hh component expression levels are upregulated in human Ulcerative Colitis patient samples and are closely correlated with expression of Th17 markers. Mechanistically we show that the T-cell-intrinsic Indian Hedgehog (Ihh) ligand signals via the signal transducer Smoothened to activate both canonical and non-canonical Hh pathways, through the Gli3 transcription factor and AMPK phosphorylation, respectively. Conclusion We uncover Hh signalling as a novel pathway controlling Th17 differentiation and pathogenicity in IBD with Gli3 acting as a newly-identified crucial regulatory transcription factor. Our work paves the way for the use of Hh inhibitors for the treatment of IBD.

CELL-AUTONOMOUS HEDGEHOG SIGNALING CONTROLS TH17 DIFFERENTIATION TO DRIVE INTESTINAL INFLAMMATION AND IS A DRUGGABLE TARGET FOR THE TREATMENT OF INFLAMMATORY BOWEL DISEASE

T helper 17 (Th17) cells play a key role in barrier protection in the gastrointestinal tract but are also key pathological drivers of Inflammatory Bowel Disease (IBD). Although a number of key transcription factors governing Th17 differentiation have been identified, the intracellular signaling pathways regulating Th17 differentiation are poorly understood. Given the highly druggable nature of many intracellular signaling pathways, understanding the signaling pathways involved in Th17 differentiation holds great promise to identify novel drug targets for the treatment of IBD.

The circular RNA circINPP4B acts as a sponge of miR-30a to regulate Th17 cell differentiation during progression of experimental autoimmune encephalomyelitis

Circular RNAs (circRNAs) regulate gene expression and participate in various biological and pathological processes. However, little is known about the effects of specific circRNAs on T helper cell 17 (Th17) differentiation and related autoimmune diseases, such as multiple sclerosis (MS). Here, using transcriptome microarray analysis at different stages of experimental autoimmune encephalomyelitis (EAE), we identified the EAE progression-related circINPP4B, which showed upregulated expression in Th17 cells from mice with EAE and during Th17 differentiation in vitro. Silencing of circINPP4B inhibited Th17 differentiation and alleviated EAE, characterized by less demyelination and Th17 infiltration in the spinal cord. Mechanistically, circINPP4B served as a sponge that directly targeted miR-30a to regulate Th17 differentiation. Furthermore, circINPP4B levels were associated with the developing phases of clinical relapsing-remitting MS patients. Our results indicate that circINPP4B plays an important role in promoting Th17 differentiation and progression of EAE by targeting miR-30a, which provides a potential diagnostic and therapeutic target for Th17-mediated MS.

WITHDRAWN: OIP5-AS1 facilitates Th17 differentiation and EAE severity by targeting miR-140-5p to regulate RhoA/ROCK2 signaling pathway

Multiple sclerosis (MS) is one of the commonest neurologic disorders globally. LncRNA OIP5-AS1 has been found to be implicated in the etiology of MS. This study was to explore the roles and molecular mechanisms of OIP5-AS1 in the development of MS. RT-qPCR assay was used to measure expressions of OIP5-AS1, miR-140-5p, IL-17A mRNA and RhoA mRNA. CD4+IL-17+ cell proportion was determined by flow cytometry. IL-17A secretion was examined by ELISA assay. Cell inflammatory infiltration and demyelination were assessed by histological analyses. The interaction between miR-140-5p and OIP5-AS1 or RhoA 3'UTR was validated by bioinformatical analysis and luciferase reporter assay. Western blot assay was performed to detect protein expressions of ROCK2 and RhoA. An experimental autoimmune encephalomyelitis (EAE) models was established to explore the role of OIP5-AS1 in MS in vivo. OIP5-AS1 expression was enhanced in MS patients. Also, elevated OIP5-AS1 level was observed during T-helper 17 (Th17) differentiation. Moreover, OIP5-AS1 promoted Th17 differentiation in vitro and contributed to the development of EAE in vivo. Mechanical explorations revealed that OIP5-AS1 targeted miR-140-5p to regulate Th17 differentiation. Moreover, RhoA was a target of miR-140-5p and miR-140-5p inhibited the activation of RhoA/ROCK2 signaling. Also, RhoA upregulation abrogated the inhibitory effects of miR-140-5p on Th17 differentiation. OIP5-AS1 contributed to EAE development by targeting miR-140-5p/RhoA and activating RhoA/ROCK2 signaling pathway, shedding light on the roles and molecular mechanisms of OIP5-AS1 in the development of MS and providing some candidate targets for the diagnose and treatment of MS.

The expression analyses of RMRP, DDX5, and RORC in RRMS patients treated with different drugs versus naïve patients and healthy controls.

Although T helper 17 (Th17) lymphocytes protect mucosal barriers against infections, they have been implicated in the development of multiple sclerosis (MS). RORC and DDX5 can regulate Th17 differentiation and the development of MS. Since RMRP, as a long non-coding RNA (lncRNA), can mediate the RORC-DDX5 complex, this lncRNA can be involved in developing MS. This study investigated the expression levels of RORC, DDX5, and RMRP in treatment-naïve relapsing-remitting multiple sclerosis (RRMS) patients, healthy controls, and RRMS patients treated with IFNβ-1α or fingolimod, or dimethyl fumarate (DMF), or glatiramer acetate (GA). There was substantial up-regulation in the expression of RORC, DDX5, and RMRP in treatment-naïve RRMS patients compared to healthy controls. Among the comparisons of their expressions in the different groups of treated patients with treatment-naïve patients, only the down-regulation of the RMRP expression level was significant in IFNβ-1α-treated patients. Also, these changes were more pronounced in female patient groups. Our analyses have highlighted the high diagnostic value of RORC, DDX5, and RMRP in treatment-naïve RRMS patients. Furthermore, RMRP has demonstrated moderate positive correlations with the expression of DDX5 and RORC in treated RRMS patients.

CaMK4-dependent phosphorylation of Akt/mTOR underlies Th17 excessive activation in experimental autoimmune prostatitis.

Chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS) is a complicated syndrome characterized by genitourinary pain in the absence of bacterial infection. Th17 cell-driven autoimmunity has been proposed as a cause of CP/CPPS. However, the factors that promote Th17-driven autoimmunity in experimental autoimmune prostatitis (EAP) and the molecular mechanisms are still largely unknown. Here, we showed that Th17 cells were excessively activated, and blockade of IL-17A could effectively ameliorate various symptoms in EAP. Furthermore, we revealed that calcium/calmodulin-dependent kinase Ⅳ (CaMK4), especially Thr196 p-CaMK4 was increased in the Th17 cells of the EAP group, which were activated by intracellular cytosolic Ca2+ . Pharmacologic and genetic inhibition of CaMK4 decreased the proportion of Th17 cells, and the protein and mRNA level of IL-17A, IL-22, and RORγt. The phosphorylation of CaMK4 was dependent on the increase in intracellular cytosolic Ca2+ concentration in Th17 cells. A mechanistic study demonstrated that inhibition of CaMK4 reduced IL-17A production by decreasing the phosphorylation of Akt-mTOR, which was well accepted to positively regulate Th17 differentiation. Collectively, our results demonstrated that Ca2+ -CaMK4-Akt/mTOR-IL-17A axis inhibition may serve as a promising therapeutic strategy for CP/CPPS.

E3 Ubiquitin Ligase Von Hippel-Lindau Protein Promotes Th17 Differentiation.

Von Hippel-Lindau (VHL) is an E3 ubiquitin ligase that targets proteins, including HIF-1α, for proteasomal degradation. VHL and HIF regulate the balance between glycolysis and oxidative phosphorylation, which is critical in highly dynamic T cells. HIF-1α positively regulates Th17 differentiation, a complex process in which quiescent naive CD4 T cells undergo transcriptional changes to effector cells, which are commonly dysregulated in autoimmune diseases. The role of VHL in Th17 cells is not known. In this study, we hypothesized VHL negatively regulates Th17 differentiation and deletion of VHL in CD4 T cells would elevate HIF-1α and increase Th17 differentiation. Unexpectedly, we found that VHL promotes Th17 differentiation. Mice deficient in VHL in their T cells were resistant to an autoimmune disease, experimental autoimmune encephalomyelitis, often mediated by Th17 cells. In vitro Th17 differentiation was impaired in VHL-deficient T cells. In the absence of VHL, Th17 cells had decreased activation of STAT3 and SMAD2, suggesting that VHL indirectly or directly regulates these critical signaling molecules. Gene expression analysis revealed that in Th17 cells, VHL regulates many cellular pathways, including genes encoding proteins involved indirectly or directly in the glycolysis pathway. Compared with wild-type, VHL-deficient Th17 cells had elevated glycolysis and glycolytic capacity. Our finding has implications on the design of therapeutics targeting the distinct metabolic needs of T cells to combat chronic inflammatory diseases.

Gm15575 functions as a ceRNA to up-regulate CCL7 expression through sponging miR-686 in Th17 cells

Compelling evidence has demonstrated that Th17 cells play an essential role in the pathogenesis of multiple sclerosis (MS). Long noncoding RNAs (lncRNAs) have been confirmed as vital regulators of immune cell differentiation and other functions. However, whether and how lncRNAs influence Th17 cell differentiation and functional behaviors remain largely unclear. Here, we identified that a lncRNA, namely Gm15575, is specifically enriched in Th17 cells and spleen tissues of EAE mice. Functionally, knockdown of Gm15575 in Th17 cells suppressed the secretion of IL17A. Mechanistically, Gm15575 served as a competing endogenous RNA (ceRNA) to block the function of miR-686, positively regulating the expression of CCL7, a pro-inflammatory chemokine with high expression in Th17 cells, and Th17 differentiation. Taken together, our study revealed that Gm15575-miR-686 axis promoted the progression of EAE by regulating Th17 differentiation and expression of CCL7 which elucidated the pathogenesis of autoimmune diseases at genetic level. Gm15575 can be involved in the course of Th17-related autoimmune diseases.

GPR68 promotes CD4 T cell survival by increasing sensitivity to CD3 signaling

Abstract CD4 T cells contribute to host defense against pathogens, but are also implicated in autoimmunity and allergies when directed against innocuous antigens. Since Th17 cells are upregulated in several autoimmune diseases, identifying genes involved in their activation, proliferation or survival may lead to novel therapies for inflammatory diseases. We previously demonstrated that the aryl hydrocarbon receptor increases expression of the proton sensing receptor GPR68 in human CD4 T cells. Since T cell clonal expansion is associated with a metabolic shift towards anaerobic glycolysis resulting in extracellular acidification, we tested the hypothesis that GPR68 is required for optimal T cell proliferation and survival following activation. To delete GPR68 in T cells, GPR68-floxed mice were crossed with a strain expressing Cre-recombinase under the CD4 promoter. Purified CD4 T cells from CD4-Cre+ and Cre-negative littermate controls were activated in vitro with anti-CD3 and Th17-inducing cytokines (IL-1b, IL-6, IL-23, TGF-b) for 1–5 days. In the control (Cre-negative) group, T cell numbers increased over the first 2 days following activation and then stabilized from days 3–5. In the GPR68-deficient group (Cre+), T cell numbers significantly decreased after day 2, demonstrating a role for GPR68 in promoting CD4 T cell survival. Nevertheless, IL-17 production was GPR68-independent, demonstrating that GPR68 did not regulate Th17 differentiation. GPR68 was especially critical for survival when low doses of anti-CD3 were used (<2.5ug/mL), but not at a high dose (10ug/mL). Overall, our data demonstrate that GPR68 increases the sensitivity of CD4 T cells to survival signals induced by CD3 stimulation.

CIP2A Constrains Th17 Differentiation by Modulating STAT3 Signaling.

SummaryCancerous Inhibitor of Protein Phosphatase 2A (CIP2A) is an oncogene and a potential cancer therapy target protein. Accordingly, a better understanding of the physiological function of CIP2A, especially in the context of immune cells, is a prerequisite for its exploitation in cancer therapy. Here, we report that CIP2A negatively regulates interleukin (IL)-17 production by Th17 cells in human and mouse. Interestingly, concomitant with increased IL-17 production, CIP2A-deficient Th17 cells had increased strength and duration of STAT3 phosphorylation. We analyzed the interactome of phosphorylated STAT3 in CIP2A-deficient and CIP2A-sufficient Th17 cells and indicated together with genome-wide gene expression profiling, a role of Acylglycerol Kinase (AGK) in the regulation of Th17 differentiation by CIP2A. We demonstrated that CIP2A regulates the strength of the interaction between AGK and STAT3, and thereby modulates STAT3 phosphorylation and expression of IL-17 in Th17 cells.

α-mangostin attenuates pristane-induced lupus nephritis by regulating Th17 differentiation.

α-mangostin, a polyphenolic xanthone derivative of mangosteen, has been reported to possess multiple therapeutic properties, such as anti-cancer, anti-allergy and anti-inflammatory activity. However, its anti-inflammatory effects in autoimmune diseases such as lupus nephritis (LN) remain unclear. In this study, we want to investigate the therapeutic effect of α-mangostin in LN. First, we elucidated the retinoic acid receptor related orphan receptor gamma t (RORγt) inhibitory activity of α-mangostin in cell-based assay and T helper 17 (Th17) differentiation in vitro assay. Then, we established a pristane-induced LN mouse model and randomly divided these into a normal control group, model control group, α-mangostin group and prednisone acetate group. Finally, anti-double-stranded DNA (anti-dsDNA) level in serum was detected by enzyme-linked immunosorbent assay, interleukin (IL)-17A and interferon (IFN)-γ expression in spleen cells by flow cytometry; histomorphology examination of kidneys was performed by periodic acid-Schiff staining and immunofluorescence analysis with an anti-immunoglobulin G (anti-IgG) and anti-IgM antibodies. We found that α-mangostin inhibited RORγt transcription activity in a cell-based assay and also polarized Th17 cells in an in vitro induction experiment. Our results also showed that α-mangostin could significantly decrease serum anti-dsDNA antibody levels, IL-17A and IFN-γ expression and alleviate renal pathological damage in the α-mangostin-treated group mice than in the model group mice. Thus, α-mangostin demonstrated its potential as a candidate therapeutic drug for LN and other Th17-mediated autoimmune diseases by inhibiting the function of Th17.

Correction: PRMT1 Plays a Critical Role in Th17 Differentiation by Regulating Reciprocal Recruitment of STAT3 and STAT5.

Th17 cells are a class of Th cells that secrete IL-17 and mediate pathogenic immunity responsible for autoimmunity including experimental autoimmune encephalomyelitis, a murine model of multiple sclerosis. Retinoic acid-related orphan receptor γ t (RORγt) is the critical transcription factor that controls the differentiation of Th17 cells. However, little is known about the transcriptional cofactors for RORγt in the regulation of Th17 differentiation. In this study, we demonstrate that protein arginine N-methyltransferase 1 (PRMT1) associates with RORγt and regulates mouse Th17 differentiation. Overexpression of PRMT1 promoted Th17 differentiation, whereas inactivation or knockdown of PRMT1 decreased Th17 differentiation while expanding Foxp3+ regulatory T cells. Consistently, pharmacological inhibition of PRMT1 impaired the generation of Th17 cells and prevented induction of experimental autoimmune encephalomyelitis in mice. Mechanistically, PRMT1-dependent modification of asymmetric histone 4 arginine 3 dimethylation is required to stabilize the stimulatory STAT3 to displace the inhibitory STAT5 at IL-17 locus, resulting in the activation of IL-17 gene. Furthermore, PRMT1-facilitated recruitment of STAT3 overcame the inhibition of Th17 differentiation exerted by IL-2-induced STAT5 activation. PRMT1 thus regulates Th17 differentiation by controlling the reciprocal recruitment of STAT3 and STAT5. Our study thus reveals PRMT1 as a novel target for alleviating Th17-mediated autoimmunity by decreasing RORγt-dependent generation of pathogenic Th17 cells.