5,6,7,8-Tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine derivative attenuates lupus nephritis with less effect to thymocyte development.

Retinoic­acid­receptor­related orphan nuclear hormone receptor gamma t (RORγt), a critical transcriptional factor of Th17 cells, is a potential therapeutic target for Th17-mediated autoimmune diseases. In addition, RORγt is essential for thymocyte survival and lymph node development, and RORγt inhibition or deficiency causes abnormal thymocyte development, thymus lymphoma, and lymph node defect. Recent study demonstrated that specific regulation of Th17 differentiation related to the hinge region of RORγt. In this research, we investigated the effect of RORγt inhibitor, 5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine derivative (TTP), in the therapy of lupus nephritis and its safety on thymocyte development. We demonstrated that TTP repressed the development of Th17 cells and ameliorated the autoimmune disease manifestation in the pristane-induced lupus nephritis mice model. The treatment of TTP in the mice did not interfere with thymocyte development, including total thymocyte number and proportion of CD4+CD8+ double-positive populations in the thymus, and had no substantial effects on the pathogenesis of thymoma. The TTP had a stronger affinity with full-length RORγt protein compared with the truncated RORγt LBD region via surface plasmon resonance, which indicated TTP binding to RORγt beyond LBD region. Molecular docking computation showed that the best binding pocket of TTP to RORγt is located in the hinge region of RORγt. In summary, as a RORγt inhibitor, TTP had a potential to develop the clinical medicine for treating Th17-mediated autoimmune diseases with low safety risk for thymocyte development.

Cryptotympana pustulata Extract and Its Main Active Component, Oleic Acid, Inhibit Ovalbumin-Induced Allergic Airway Inflammation through Inhibition of Th2/GATA-3 and Interleukin-17/RORγt Signaling Pathways in Asthmatic Mice.

Cicadae Periostracum (CP), derived from the slough of Cryptotympana pustulata, has been used as traditional medicine in Korea and China because of its diaphoretic, antipyretic, anti-inflammatory, antioxidant, and antianaphylactic activities. The major bioactive compounds include oleic acid (OA), palmitic acid, and linoleic acid. However, the precise therapeutic mechanisms underlying its action in asthma remain unclear. The objective of this study was to determine the antiasthmatic effects of CP in an ovalbumin (OVA)-induced asthmatic mouse model. CP and OA inhibited the inflammatory cell infiltration, airway hyperresponsiveness (AHR), and production of interleukin (IL)7 and Th2 cytokines (IL-5) in the bronchoalveolar lavage fluid and OVA-specific imunoglobin E (IgE) in the serum. The gene expression of IL-5, IL-13, CCR3, MUC5AC, and COX-2 was attenuated in lung tissues. CP and OA might inhibit the nuclear translocation of GATA-binding protein 3 (GATA-3) and retinoic acid receptor-related orphan receptor γt (RORγt) via the upregulation of forkhead box p3 (Foxp3), thereby preventing the activation of GATA-3 and RORγt. In the in vitro experiment, a similar result was observed for Th2 and GATA-3. These results suggest that CP has the potential for the treatment of asthma via the inhibition of the GATA-3/Th2 and IL-17/RORγt signaling pathways.

Epigallocatechin gallate ameliorates airway inflammation by regulating Treg/Th17 imbalance in an asthmatic mouse model.

Epigallocatechin gallate (EGCG) is a polyphenol that is found in green tea that has been shown to ameliorate airway inflammation in an ovalbumin-sensitized asthmatic mouse model. The purpose of this study was to investigate whether the immunomodulatory and anti-inflammatory effects of EGCG by regulating the regulatory T cell (Treg)/Th 17 cells balance in this model. Female BALB/c mice were sensitized and challenged with ovalbumin by intraperitoneal injection. EGCG was administered to asthmatic mice intraperitoneally 1 h before each OVA challenge. Airway hyperresponsiveness (AHR) was measured, and lung inflammatory infiltrations were assessed by hematoxylin and eosin (HE) staining. Serum OVA-specific IgE levels, Interleukin-10 (IL-10) levels and Interleukin-17A (IL-17A) levels in the bronchoalveolar lavage fluid (BALF), serum, and splenocyte culture supernatants were measured by ELISA. Flow cytometry was used to assess the effects of EGCG on the frequency of CD4+CD25+Foxp3+Treg cells in the splenocytes and real-time PCR method was used to measure the expression of Forkhead box P3 (Foxp3) mRNA and retinoid-related orphan receptor gammat (RORγt) mRNA in the lung tissue. The results showed that administration of EGCG significantly decreased AHR and OVA specific IgE in the serum, increased IL-10 levels in the BALF, serum, and splenocyte culture supernatant, and the frequency of CD4+CD25+Foxp3+Treg cells in the splenocytes in asthmatic mice. Administration of EGCG also ameliorated airway inflammation and eosinophil infiltrations in asthmatic mice. These results suggested that EGCG likely ameliorated OVA-induced airway inflammation by increasing the production of IL-10, the number of CD4+CD25+Foxp3+Treg cells and expression of Foxp3 mRNA in the lung tissue, and it could be an effective agent for treating asthma.

A novel RORγt inhibitor is a potential therapeutic agent for the topical treatment of psoriasis with low risk of thymic aberrations.

BACKGROUND: Retinoic acid receptor-related orphan receptor gamma t (RORγt) has critical roles in the development, maintenance and function of interleukin (IL)-17-producing cells and is a highly attractive target for the treatment of IL-17-mediated autoimmune disease, particularly psoriasis. On the other hand, RORγt is also critical for controlling apoptosis during thymopoiesis, and genetic RORγt ablation or systematic RORγt inhibition cause progressive thymic aberrations leading to T cell lymphomas. OBJECTIVE: We investigated whether topical administration of our novel RORγt inhibitor, S18-000003 has therapeutic potential for psoriasis with low risk of thymic aberrations. METHODS: We evaluated the effect of topical S18-000003 on psoriasis-like skin inflammation and influence on the thymus in a 12-O-tetradecanoylphorbol-13-acetate-induced K14.Stat3C mouse psoriasis model. RESULTS: S18-000003 markedly inhibited the development of psoriatic skin inflammation via suppression of the IL-17 pathway. In the skin, S18-000003 suppressed all subsets of IL-17-producing cells that we previously identified in this psoriasis model: Th17 cells, Tc17 cells, dermal γδ T cells, TCR- cells that probably included innate lymphoid cells, and CD4-CD8- double-negative αß T cells. Notably, neither reduction of CD4+CD8+ double-positive thymocytes nor dysregulation of cell cycling was observed in S18-000003-treated mice, even at a high dose. CONCLUSION: Our topically administered RORγt inhibitor is a potential therapeutic agent for psoriasis with low risk of thymic lymphoma.

A polysaccharide from Eclipta prostrata alleviates experimental autoimmune encephalomyelitis through inhibiting Th17 cells.

Eclipta prostrata has long been used as a medicinal herb in China. EAP20-1, a homogeneous polysaccharide with anti-complementary activity had been obtained from E. prostrate by using anion-exchange and size-exclusion chromatography. In this study, we found that EAP20-1 could inhibit in vitro lymphocyte proliferation stimulated by concanavalin-A or anti-CD3/anti-CD28 antibodies. Furthermore, in experimental autoimmune encephalomyelitis (EAE) mice, EAP20-1 treatment relieved the clinical symptoms, accompanied by reduced neuroinflammation and demyelination in spinal cords. Mechanistically, EAP20-1 reduced the mRNA expression of interleukin (IL)-17, IL-22, and RAR-related orphan receptor gamma t (RORγt) in the spleen; inhibited auto-reactive T cell proliferation and decreased the percentage of Th17 cells in response to myelin oligodendrocyte glycoprotein (MOG35-55) ex vivo. Moreover, EAP20-1 directly inhibited naïve CD4 + T cells differentiate into Th17 cells in vitro. These results indicating EAP20-1 could benefit EAE through inhibiting Th17 cell differentiation and suggesting a therapeutic potential of EAP20-1 in MS.

Pharmacological inhibition of RORγt suppresses the Th17 pathway and alleviates arthritis in vivo.

Retinoic acid receptor-related-orphan-receptor-C (RORγt) is the key transcription factor that is driving the differentiation of IL-17 producing T-helper 17 (Th17) cells that are implicated in the pathology of various autoimmune and inflammatory diseases. Based on the importance of RORγt in promoting Th17-driven pathology, there is considerable interest to develop low-molecular-weight compounds with the aim of inhibiting the transcriptional activity of this nuclear hormone receptor. In this article, we describe the in vitro and in vivo pharmacology of a potent and selective small-molecular-weight RORγt inverse agonist. The compound binds to the ligand binding domain (LBD) of RORγt leading to displacement of a co-activator peptide. We show for the first time that a RORγt inverse agonist down-regulates permissive histone H3 acetylation and methylation at the IL17A and IL23R promoter regions, thereby providing insight into the transcriptional inhibition of RORγt-dependent genes. Consistent with this, the compound effectively reduced IL-17A production by polarized human T-cells and γδT-cells and attenuated transcription of RORγt target genes. The inhibitor showed good in vivo efficacy in an antigen-induced arthritis model in rats and reduced the frequencies of IL-17A producing cells in ex vivo recall assays. In summary, we demonstrate that inhibiting RORγt by a low-molecular-weight inhibitor results in efficient and selective blockade of the pro-inflammatory Th17/IL-17A pathway making it an attractive target for Th17-mediated disorders.

The herbal decoction modified Danggui Buxue Tang attenuates immune-mediated bone marrow failure by regulating the differentiation of T lymphocytes in an immune-induced aplastic anemia mouse model.

Angelicae Sinensis, Radix Astragali and Rhizoma Coptidis are all herbs of modified Danggui Buxue Tang (DGBX) and are extensively applied herbs in traditional Chinese medicine for the treatment of anemia and inflammation. In this study, immune-induced AA mice were used as an animal model, and the immunosuppressive agent, Ciclosporin A (CsA), was used as a positive control. Multiple pro-inflammatory cytokines were examined by bead-based multiplex flow cytometry. The T-cell subsets were assessed using a fluorescence-activated cell sorter (FACS). Western blot analysis was used to estimate the protein expression levels of specific transcription factors for T helper cells (Th1, Th2 and Th17) and key molecules of the Janus-activated kinase (Jak)/signal transducer and activator of transcription (Stat3) signaling pathway. DGBX treatment could significantly increase the production of whole blood cells in peripheral blood (PB); inhibit the expansion of Th1 and Th17 cells; increase the differentiation of Th2 and Tregs cells; regulate the expression levels of T-bet, GATA-3, RORγ and proinflammatory cytokines; and decrease the expression levels of key molecules in the Jak/Stat signaling pathway. These results indicate that DGBX can regulate the differentiation of T lymphocytes, resulting in immunosuppressive and hematogenic functions on AA mice. DGBX might be a good candidate for inclusion in a randomized study for AA with more data on the possible side effects and doses used in humans. Ultimately, it may be used for applications of traditional medicine against AA in modern complementary and alternative immunosuppressive therapeutics.

Development of a Topical Treatment for Psoriasis Targeting RORγ: From Bench to Skin.

BACKGROUND: Psoriasis is a chronic inflammatory skin disorder involving marked immunological changes. IL-17-targeting biologics have been successful in reducing the disease burden of psoriasis patients with moderate-to-severe disease. Unfortunately, the stratum corneum prevents penetration of large molecule weight proteins, including monoclonal antibodies. Thus, for the majority of psoriasis patients ineligible for systemic treatments, a small molecule targeting RORγt, the master regulator of IL-17 family cytokines, may represent an alternative topical medicine with biologic-like efficacy. METHODS AND FINDINGS: The preclinical studies described in this manuscript bridge the gap from bench to bedside to provide the scientific foundation for a compound entering clinical trials for patients with mild to moderate psoriasis. In addition to several ex vivo reporter assays, primary T cell cultures, and the imiquimod mouse model, we demonstrate efficacy in a newly developed human ex vivo skin assay, where Th17-skewed cytokine expression is induced from skin-resident immune cells. Importantly, the skin barrier remains intact allowing for the demonstration of topical drug delivery. With the development of this novel assay, we demonstrate potent compound activity in the target tissue: human skin. Finally, target engagement by this small molecule was confirmed in ex vivo lesional psoriatic skin. CONCLUSIONS: Our work describes a progressive series of assays to demonstrate the potential clinical value of a novel RORγ inverse agonist small molecule with high potency and selectivity, which will enter clinical trials in late 2015 for psoriasis patients.

Innate lymphoid cells: parallel checkpoints and coordinate interactions with T cells.

Protection of epithelial and mucosal surfaces is required for survival. The recent discovery of a diverse array of innate lymphoid cells that lie immediately beneath these surfaces has unexpectedly uncovered an entire defense system distinct from the adaptive system essential to protect these barriers. This multilayered design provides a robust system through coupling of two highly complementary networks to ensure immune protection. Here, we discuss the similarities in the hardwiring and diversification of innate lymphoid cells and T cells during mammalian immune responses.

Curcumin relieves TPA-induced Th1 inflammation in K14-VEGF transgenic mice.

Curcumin has been confirmed to have anti-inflammatory properties in addition to the ability to decrease the expression of pro-inflammatory cytokines in keratinocytes. It was suggested that the interleukin-23 (IL-23)/IL-17A cytokine axis played a critical role in the pathogenesis of 12-O-tetradecanoyl phorbol 12-myristate 13-acetate (TPA)-induced K14-VEGF transgenic psoriasis-like mice model. Here, we report that topical use of a curcumin gel formulation inhibited TPA-induced Th1 inflammation in K14-VEGF transgenic mice ears but not Th17 inflammation as expected. Real-time PCR showed that mRNA levels of IL-23, IL-17A, IL-22, IL-6 and TNFα cytokines failed to increase after TPA-induction in K14-VEGF transgenic mice ear skin; but the mRNA level of IFNγ increased significantly at the same time. Furthermore, TPA-induction up-regulated the TCRγδ protein but failed to impact the CCR6 protein, which means that the proliferation of γδ T cells is incapable of IL-17A production. We find that curcumin is capable of relieving TPA-induced inflammation by directly down-regulating IFNγ production. In conclusion, curcumin inhibits TPA-induced Th1 inflammation in K14-VEGF transgenic mice which has not been previously described.

In vivo regulation of gene expression and T helper type 17 differentiation by RORγt inverse agonists.

The orphan nuclear receptor, retinoic acid receptor-related orphan nuclear receptor γt (RORγt), is required for the development and pathogenic function of interleukin-17A-secreting CD4(+) T helper type 17 (Th17) cells. Whereas small molecule RORγt antagonists impair Th17 cell development and attenuate autoimmune inflammation in vivo, the broader effects of these inhibitors on RORγt-dependent gene expression in vivo has yet to be characterized. We show that the RORγt inverse agonist TMP778 acts potently and selectively to block mouse Th17 cell differentiation in vitro and to impair Th17 cell development in vivo upon immunization with the myelin antigen MOG35-55 plus complete Freund's adjuvant. Importantly, we show that TMP778 acts in vivo to repress the expression of more than 150 genes, most of which fall outside the canonical Th17 transcriptional signature and are linked to a variety of inflammatory pathologies in humans. Interestingly, more than 30 genes are related with SMAD3, a transcription factor involved in the Th17 cell differentiation. These results reveal novel disease-associated genes regulated by RORγt during inflammation in vivo, and provide an early read on potential disease indications and safety concerns associated with pharmacological targeting of RORγt.

TLR-induced cytokines promote effective proinflammatory natural Th17 cell responses.

Naive CD4 lymphocytes undergo a polarization process in the periphery to become induced Th17 (iTh17) cells. Using retinoic acid-related orphan receptor γt (RORγt)-gfp mice, we found that RORγt and the transcription factor promyelocytic leukemia zinc finger (PLZF) are valuable new markers to identify the recently described natural Th17 (nTh17) cell population. nTh17 cells are thymically committed to promptly produce large amounts of IL-17 and IL-22. In this study, we show that, in addition to responding to TCR cross-linking, nTh17 cells secrete IL-17 and IL-22 when stimulated with IL-23 plus IL-1ß, either in recombinant form or in supernatants from TLR4-activated dendritic cells. This innate-like ability of RORγt(+) nTh17 cells to respond to TLR4-induced cytokines was not shared by iTh17 cells. The other distinct properties of RORγt(+) nTh17 cells are their high expression of PLZF and their absence from lamina propria; iTh17 cells are found therein. RORγt(+) nTh17 cells are present in the thymus of germ-free RORγt-gfp and IL-6(-/-) RORΓ: t-gfp mice, indicating that these cells do not require symbiotic microbiota or IL-6 for their generation. Finally, we found that PLZF(+)RORγt(+) nTh17 cells represent one of the primary IL-17-producing innate-like T cell populations in a TLR7 imiquimod model of psoriasis-like disorder, indicating their involvement in this kind of lesion. Collectively, our results reveal RORγt and PLZF as characteristic markers for identifying nTh17 cells and demonstrate one of their novel properties: the ability to respond promptly to TLR-dependent proinflammatory stimuli without TCR engagement, placing them as members of the innate-like T cell family.

Interleukin-10 attenuation of collagen-induced arthritis is associated with suppression of interleukin-17 and retinoid-related orphan receptor γt production in macrophages and repression of classically activated macrophages.

INTRODUCTION: Our objective in the present study was to determine the signaling pathway of interleukin 10 (IL-10) for modulating IL-17 expression in macrophages and the importance of this mediation in collagen-induced arthritis (CIA). METHODS: IL-10-knockout (IL-10⁻/⁻) mice and wild-type (WT) mice were immunized with chicken type II collagen (CII) to induce arthritis. The expression levels of IL-17 and retinoid-related orphan receptor γt (RORγt) in macrophages and joint tissues of IL-10⁻/⁻ and WT mice were analyzed by enzyme-linked immunosorbent assay, quantitative RT-PCR (qRT-PCR) and Western blotting. The F4/80 macrophages and positive IL-17-producing macrophages in synovial tissues of the mice were determined by immunohistochemistry. The populations of classically activated macrophage (M1) and alternatively activated macrophage (M2) phenotypes were analyzed by flow cytometry. The expression of genes associated with M1 and M2 markers was analyzed by qRT-PCR. RESULTS: Compared to WT mice, IL-10⁻/⁻ mice had exacerbated CIA development, which was associated with increased production of T helper 17 cell (Th17)/Th1 proinflammatory cytokines and CII-specific immunoglobulin G2a antibody after CII immunization. Macrophages in IL-10⁻/⁻ mice had increased amounts of IL-17 and RORγt compared with the amounts in WT mice with CIA. Immunofluorescence microscopy showed that the number of IL-17-producing macrophages in synovial tissues was significantly higher in IL-10⁻/⁻ mice than in WT mice. IL-10 deficiency might promote macrophage polarization toward the proinflammatory M1 phenotype, which contributes to the rheumatoid arthritis inflammation response. CONCLUSION: IL-10 inhibits IL-17 and RORγt expression in macrophages and suppresses macrophages toward the proinflammatory M1 phenotype, which is important for the role of IL-10 in mediating the pathogenesis of CIA.

Oleanolic acid suppresses ovalbumin-induced airway inflammation and Th2-mediated allergic asthma by modulating the transcription factors T-bet, GATA-3, RORγt and Foxp3 in asthmatic mice.

The natural product oleanolic acid is commonly found in a variety of medicinal plants. It is a triterpenoid compound known for its anti-inflammatory effects as well as various other pharmacological properties. The aim of the current study was to use a mouse model of allergic asthma to investigate whether oleanolic acid has anti-asthmatic effects, and if so, to determine the mechanism of these effects. Oleanolic acid suppressed eosinophil infiltration, allergic airway inflammation, and Penh, which occurred by suppressing the production of IL-5, IL-13, IL-17, and ovalbumin-specific IgE through the upregulation of T-bet and Foxp3, and the downregulation of GATA-3 and RORγt. The therapeutic effect of oleanolic acid was due to suppression of Th2 cytokines (IL-5 and IL-13), B cell-dependent production of OVA-specific IgE, and Gr-1 expression through the T-bet, GATA-3, retinoic acid-related orphan receptor γ t (RORγ t) and forkhead box p3 (Foxp3) transcription pathways. It is therefore reasonable to suggest that the anti-inflammatory and anti-asthmatic effects of oleanolic acid may be exerted through inhibition of the GATA-3 and RORγt pathways.

Interleukin-23 is critical for full-blown expression of a non-autoimmune destructive arthritis and regulates interleukin-17A and RORgammat in gammadelta T cells.

INTRODUCTION: Interleukin (IL)-23 is essential for the development of various experimental autoimmune models. However, the role of IL-23 in non-autoimmune experimental arthritis remains unclear. Here, we examined the role of IL-23 in the non-autoimmune antigen-induced arthritis (AIA) model. In addition, the regulatory potential of IL-23 in IL-17A and retinoic acid-related orphan receptor gamma t (RORgammat) expression in CD4+ and TCRgammadelta+ T cells was evaluated systemically as well as at the site of inflammation. METHODS: Antigen-induced arthritis was induced in wild-type, IL-23p19-deficient and IL-17 Receptor A - knockout mice. At different time points, synovial cytokine and chemokine expression was measured. At days 1 and 7 of AIA, splenocytes and joint-infiltrating cells were isolated and analyzed for intracellular IL-17A and interferon (IFN)-gamma ex-vivo by flow cytometry. In splenic CD4+ and TCRgammadelta+ T cells gene expression was quantified by flow cytometry and quantitative PCR. RESULTS: IL-23 was critical for full-blown AIA. Lack of IL-23 did not prevent the onset of joint inflammation but stopped the progression to a destructive synovitis. IL-23 regulated IL-17A expression in CD4+ T cells in the spleen. Of note, IL-17A and IFN-gamma expression was reduced in CD4+ T cells in the inflamed joints of IL-23p19-deficient mice. Interestingly, IL-23 was also critical for the induction of IL-17A and RORgammat but not IFN-gamma in TCRgammadelta+ T cells in the inflamed joints. The importance of the IL-23/IL-17 axis was further confirmed using IL-17 Receptor A knockout mice showing significantly milder AIA compared to control mice, with a disease course comparable to that of IL-23p19-deficient mice. CONCLUSIONS: These data show that IL-23 is critical for full-blown expression of a non-autoimmune destructive arthritis and regulates the proportion of IL-17A and IFN-gamma-positive CD4+ T cells at the site of inflammation. Furthermore, IL-23 regulates IL-17A and RORgammat expression in TCRgammadelta T cells in arthritis. These findings indicate that regulating the IL-23 pathway may have therapeutic potential in non-autoimmune arthritis.

Amelioration of experimental autoimmune encephalomyelitis by curcumin treatment through inhibition of IL-17 production.

Experimental autoimmune encephalomylitis (EAE), an animal mode of multiple sclerosis (MS), was previously considered that be mediated by Th1 cells. However, a number of recent studies provided strong evidence that T helper cells that produce IL-17 play a dominant role in the pathogenesis of EAE. Curcumin (1,7-Bis 94-hydroxy-3-methoxyphenyl)-1,6 heptadiene-3, 5-di-one) is a naturally occurring polyphenolic phytochemical isolated from the rhizome of the medicinal plant Curcuma longa. It has been strongly implicated as an anti-inflammatory agent, but the precise mechanisms of its action are largely unknown. In the present study, we have investigated the efficacy and mechanism of curcumin against EAE. The treatment of Lewis rats with curcumin significantly reduced the clinical severity of EAE, and had a dramatic reduction in the number of inflammatory cells infiltration in the spinal cord. The proliferation of the MBP-reaction lymphocyte also was reduced in a curcumin dose-dependent manner. Furthermore, the mRNA expression of the cytokine profiles was assessed by quantitative reverse-transcription polymerase chain reaction (qRT-PCR), revealing the dramatic decrease of IL-17, TGF-beta, IL-6, IL-21, STAT3, and RORgammat expression in curcumin-treated groups and STAT3-phosphorylation also was inhibited. These findings indicated that curcumin amelioration EAE was, to a large extent, due to inhibit differentiation and development of Th17 cells depends on down-regulating expression of IL-6, IL-21, RORgammat signaling and inhibition STAT3-phosphorylation, suggests it is useful in the treatment of MS and other Th17 cell-mediated inflammatory diseases.