YY1 alleviates lupus nephritis-induced renal injury by reducing the Th17/Treg cell ratio via the IFN-γ/Fra2 axis.

Lupus nephritis (LN) is associated with extensive injury and nephron loss in the afflicted kidney. Evidence has revealed the involvement of dysregulated Yin Yang 1 (YY1), a reported inflammatory modulator, in LN-induced kidney injury, and our microarray profile identified downregulated YY1 expression. Therefore, this study explored the functional relevance and mechanism of YY1 in LN-induced kidney injury. LN was modeled in mice by intraperitoneal injection of pristane, and Jurkat cells (CD41 human T lymphocytes) were activated with TNF-α to mimic the inflammatory environment found in LN. The expression patterns of YY1 and bioinformatics predictions of the downstream factor IFN-γ were confirmed in renal tissues from the mice with LN using qRT-PCR and Western blot analyses. The contents of proinflammatory cytokines in mouse serum samples and cell supernatants were determined using enzyme-linked immunosorbent assays (ELISAs). Ectopic expression and depletion approaches were subsequently used in vitro and in vivo to examine the effects of the YY1/IFN-γ/Fra2/PARP-1/FOXO1 axis on TNF-α-induced inflammation and LN-induced kidney injury. The results showed downregulated expression of YY1 and FOXO1 in the kidney tissues of the mice with LN. Increased proinflammatory factor production was observed in the mice with LN and TNF-α-treated Jurkat cell supernatant, accompanied by increased cell apoptosis and a high ratio of Th17/Treg cells, and these effects were reversed by YY1 restoration. YY1 was further shown to inhibit IFN-γ expression and thereby downregulate Fra2 expression. Fra2 depletion then inhibited PARP-1 expression and promoted FOXO1 expression to suppress cell apoptosis and the release of inflammatory factors. Collectively, our findings revealed that YY1 may alleviate LN-induced renal injury via the IFN-γ/Fra2/PARP-1/FOXO1 axis.

The Purinergic Receptor P2X4 Promotes Th17 Activation and the Development of Arthritis.

Purinergic signaling plays a major role in T cell activation leading to IL-2 production and proliferation. However, it is unclear whether purinergic signaling contributes to the differentiation and activation of effector T cells. In this study, we found that the purinergic receptor P2X4 was associated with human Th17 cells but not with Th1 cells. Inhibition of P2X4 receptor with the specific antagonist 5-BDBD and small interfering RNA inhibited the development of Th17 cells and the production of IL-17 by effector Th17 cells stimulated via the CD3/CD28 pathway. Our results showed that P2X4 was required for the expression of retinoic acid-related orphan receptor C, which is the master regulator of Th17 cells. In contrast, inhibition of P2X4 receptor had no effect on Th1 cells and on the production of IFN-γ and it did not affect the expression of the transcription factor T-bet (T-box transcription factor). Furthermore, inhibition of P2X4 receptor reduced the production of IL-17 but not of IFN-γ by effector/memory CD4+ T cells isolated from patients with rheumatoid arthritis. In contrast to P2X4, inhibition of P2X7 and P2Y11 receptors had no effects on Th17 and Th1 cell activation. Finally, treatment with the P2X4 receptor antagonist 5-BDBD reduced the severity of collagen-induced arthritis in mice by inhibiting Th17 cell expansion and activation. Our findings provide novel insights into the role of purinergic signaling in T cell activation and identify a critical role for the purinergic receptor P2X4 in Th17 activation and in autoimmune arthritis.

Identification of Corosolic and Oleanolic Acids as Molecules Antagonizing the Human RORγT Nuclear Receptor Using the Calculated Fingerprints of the Molecular Similarity.

RORγT is a protein product of the RORC gene belonging to the nuclear receptor subfamily of retinoic-acid-receptor-related orphan receptors (RORs). RORγT is preferentially expressed in Th17 lymphocytes and drives their differentiation from naive CD4+ cells and is involved in the regulation of the expression of numerous Th17-specific cytokines, such as IL-17. Because Th17 cells are implicated in the pathology of autoimmune diseases (e.g., psoriasis, inflammatory bowel disease, multiple sclerosis), RORγT, whose activity is regulated by ligands, has been recognized as a drug target in potential therapies against these diseases. The identification of such ligands is time-consuming and usually requires the screening of chemical libraries. Herein, using a Tanimoto similarity search, we found corosolic acid and other pentacyclic tritepenes in the library we previously screened as compounds highly similar to the RORγT inverse agonist ursolic acid. Furthermore, using gene reporter assays and Th17 lymphocytes, we distinguished compounds that exert stronger biological effects (ursolic, corosolic, and oleanolic acid) from those that are ineffective (asiatic and maslinic acids), providing evidence that such combinatorial methodology (in silico and experimental) might help wet screenings to achieve more accurate results, eliminating false negatives.

Natural Herbal Remedy Wumei Decoction Ameliorates Intestinal Mucosal Inflammation by Inhibiting Th1/Th17 Cell Differentiation and Maintaining Microbial Homeostasis.

BACKGROUND: Evidence has shown that the traditional Chinese herbal medicine Wumei decoction (WMD) has a protective effect on ulcerative colitis. Here, we studied the anti-inflammatory effects and potential mechanisms of WMD on chronic colitis in mice. METHODS: A dextran sulfate sodium (DSS)-induced chronic colitis model and CD45RBhighCD4+ T cell transfer model were established in mice. Body weight, Disease Activity Index, and colon length were assessed, and histopathology was confirmed by hematoxylin and eosin staining. Colon tissue samples were collected to detect the frequencies of various immune cells, expression of cytokines, and tight junction-related proteins using flow cytometry, quantitative real-time polymerase chain reaction, and enzyme-linked immunosorbent assay, respectively. 16S ribosomal DNA sequencing was performed to distinguish differential microbiota of fecal samples. RESULTS: Severe chronic colitis was observed in mice after DSS exposure and in Rag1-/- mice reconstituted with CD45RBhighCD4+ T cells, as manifested by weight loss, hematochezia, and shortening and thickening of the colon, which were reversed by WMD treatment. WMD markedly suppressed intestinal mucosal CD4+ T cell differentiation and the secretion of proinflammatory cytokines (eg, tumor necrosis factor α, interleukin-1ß, interferon γ, and IL-17A) by flow cytometry, quantitative real-time polymerase chain reaction, and enzyme-linked immunosorbent assay, respectively. Moreover, WMD promoted the expression of occludin, zonula occludens-1, and E-cadherin, thereby maintaining the epithelial barrier function. Additionally, 16S ribosomal DNA sequencing revealed that WMD regulated the dysbiosis of gut microbiota in CD45RBhighCD4+ T cell-reconstituted Rag1-/- mice, evidenced by an increase of Allobaculum and Bacteroides and a decrease of Ileibacterium. CONCLUSIONS: WMD ameliorates chronic colitis in mice induced by DSS or reconstituted with CD45RBhighCD4+ T cells through suppressing Th1/Th17 cell differentiation and the secretion of proinflammatory cytokines, maintaining epithelial barrier function, and improving the dysbiosis.

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

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

Dendrobium huoshanense stem polysaccharide ameliorates rheumatoid arthritis in mice via inhibition of inflammatory signaling pathways.

The present study explored the beneficial effect of Dendrobium huoshanense stem polysaccharide (cDHPS) after oral administration on rheumatoid arthritis (RA) using type Ⅱ collagen-induced arthritis (CIA) mouse model. It was found that cDHPS effectively alleviated joint swelling, synovial hyperplasia, pannus formation, cartilage erosion and bone destruction in CIA mice. Concurrently, cDHPS remodeled the balance of Th17 and regulatory T cells, reduced the secretion of pro-inflammatory mediators related to fibroblast-like synoviocyte activation, angiogenesis, articular cartilage degradation and osteoclast differentiation, inhibited HIF-1α expression and promoted anti-inflammatory mediator release in the joint tissues and serum of CIA mice. Western blot of joint tissues showed that cDHPS significantly inhibited the phosphorylation of IκB, p65, JNK, p38, ERK1/2, AKT, PI3K, JAK1 and STAT3 in CIA mice. These results suggest that cDHPS possesses the potential of ameliorating RA and its anti-RA effect may be attributed to the inhibition of inflammatory signaling pathways.

Vitamin D Supplementation Modulates ICOS+ and ICOS- Regulatory T Cell in Siblings of Children With Type 1 Diabetes.

OBJECTIVES: Vitamin D plays an immunoregulatory activity. The aim of this study was to assess the correlation between blood serum 25(OH)D levels and Th17 and Treg circulating subsets, mainly Treg/inducible costimulatory-positive (ICOS+), which seems to have a protective role in autoimmunity, in children with type 1 diabetes mellitus (T1D) and their healthy siblings (S). The secondary aim was to evaluate the impact of vitamin D supplementation on these subsets. PATIENTS AND METHODS: 22 T1D and 33 S were enrolled. Glucose, hemoglobin A1c, 25 OH vitamin D (25[OH]D), T helper type 17 (Th17; CD4+CCR6+), regulatory T cells (Treg; CD4+CD25+Foxp3+), and Treg/ICOS+ cells were evaluated. According to human leukocyte antigen (HLA) haplotypes, subjects were classified as "at risk" (HLA+), "protective haplotypes" (HLA-; "nested controls"), and "undetermined" (HLAUND). T1D and S subjects were supplemented with cholecalciferol 1000 IU/die and evaluated after 6 months. RESULTS: Vitamin D insufficiency (74.4%) and deficiency (43%) were frequent. S subjects with 25(OH)D levels <25 nmol/L had Th17, Treg (p < 0.01), and Treg/ICOS+ (P < 0.05) percentages higher than subjects with 25(OH)D >75 nmol/L. Treg/ICOS+ percentages (P < 0.05) were higher in HLA- S subjects compared to percentages observed in S with T1D. At baseline, in S subjects, a decreasing trend in Th17 and Treg/ICOS+ values (P < 0.05) from vitamin D deficiency to sufficiency was observed; 25(OH)D levels were negative predictors of Treg/ICOS+ (R2 = 0.301) and Th17 percentages (R2 = 0.138). After 6 months, supplemented S subjects showed higher 25(OH)D levels (P < 0.0001), and lower Th17 (P < 0.0001) and Treg/ICOS+ (P < 0.05) percentages than at baseline; supplemented T1D patients only had a decrease in Th17 levels (P < 0.05). CONCLUSION: Serum 25(OH)D levels seem to affect Th17 and Treg cell subsets in S subjects, consistent with its immunomodulating role. HLA role should be investigated in a larger population.

Huagan tongluo Fang improves liver fibrosis via down-regulating miR-184 and up-regulating FOXO1 to inhibit Th17 cell differentiation.

BACKGROUND: The purpose of this research is to reveal the improvement effect and potential mechanism of Huagan tongluo Fang (HGTLF) on liver fibrosis. METHODS: A mouse model of liver fibrosis induced by CCl4 was established to analyze the effect of HGTLF on liver fibrosis. The expression changes of miRNA after HGTLF stimulation were detected by qRT-PCR. After interference with miR-184 in Th17 cells, the concentration of IL-17A in cell culture supernatants was detected by ELISA and the proportion of Th17 cells was analyzed by flow cytometry. The relationship between miR-184 and FOXO1 was verified by online software and dual-luciferase reporter system. After HGTLF treatment of Th17 cells overexpressing miR-184, the protein level of FOXO1 was detected by Western blot. RESULTS: HGTLF could significantly improve liver fibrosis in mice. By qRT-PCR, miR-184 was most significantly expressed after HGTLF drug stimulation, and miR-184 was considered to be the major RNA involved in Th17 cell differentiation. Interference with miR-184 in Th17 cells inhibited the differentiation of Th17 cells. By online software and dual-luciferase reporter system assay, the direct interaction of miR-184 with FOXO1 was confirmed. After HGTLF treatment of Th17 cells overexpressing miR-184, FOXO1 protein levels were significantly up-regulated and inhibited the differentiation of Th17 cells, which was reversed by miR-184 inhibitors. The Vivo experiments also confirmed the improvement effect of HGTLF on liver fibrosis in mice. CONCLUSION: Our results indicated that HGTLF could improve liver fibrosis via down-regulating miR-184 and up-regulating of FOXO1 to inhibit Th17 cell differentiation.

The Inhibitory Effects of Pentacyclic Triterpenes from Loquat Leaf against Th17 Differentiation.

BACKGROUND: Loquat leaf is an herb that is commonly used in traditional Chinese medicine (TCM) for its anti-inflammatory properties. Numerous studies have demonstrated that Th17 cells play a fundamental role in mediating SLE pathological deterioration. In our study, we investigated the inhibitory effect of pentacyclic triterpenes from loquat leaf on T helper 17 (Th17) cells and the therapeutic efficacy of OA in Lupus nephritis (LN) development. METHODS: We isolated three pentacyclic triterpene compounds rom loquat leaf by bioassay-directed fractionation and separation method. There were methyl corosolate (MC), uvaol (UL), and oleanolic acid (OA) Firstly, we elucidated Retinoic acid receptor-related orphan receptor gamma t (RORγt) inhibitory activity of these three compounds in the cell-based assay and Th17 differentiation in vitro assay. Then, we used OA-treated pristine-induced LN mice to evaluate the therapeutic effects of OA in LN development. Anti-dsDNA level in serum was detected by enzyme-linked immunosorbent assay (ELISA), interleukin 17A (IL-17A) and interferon-γ (IFN-γ) expression in spleen cells by Flow cytometry (FCM), histomorphologic examination of kidneys were performed by periodic acid schiff (PAS) staining and immunofluorescence analysis. RESULTS: Pentacyclic triterpene compounds (MC, UL, OA) displayed inhibition of RORγt activity in cell-based assay and Th17 differentiation in vitro. Furthermore, our results also showed that OA could significantly decrease serum anti-dsDNA antibody levels, IL-17A and IFN-γ expression and alleviate renal pathological damage in OA-treated group mice than in the model group mice. CONCLUSION: These results demonstrated that OA can improve the clinical manifestation of LN, indicating potential application in SLE therapy.

[Effect of triptolide on Th17/Treg cells in spleen].

Triptolide( TP) is isolated from the traditional Chinese medicine Tripterygium wilfordii,which exhibits notable immuneregulative effect. Th17 cells involve in inflammatory response and Treg cells contribute to immune tolerance. They both play an important role in immune response. Previous studies have investigated that TP induced hepatic Th17/Treg imbalance. However,the effect of TP on spleen Th17/Treg cells remains unclear. Therefore,the aim of present study was to investigate the effect of TP on Th17/Treg cells in spleen. In this study,the effect of TP on the proliferation of splenic lymphocyte was detected by cytotoxicity test in vitro. After different concentrations of TP( 2. 5,5,20,40 nmol·L~(-1)) were given to splenic lymphocyte,cytokines secreted from the supernatant of splenic lymphocyte were detected by cytometric bead array,and the expression of suppressor of cytokine signaling( SOCS) mRNA was detected by qRT-PCR. Female C57 BL/6 mice were continuously observed for 24 h after treatment of 500 µg·kg-1 TP. The effects of TP on the splenic tissue structure and the percentage of Th17/Treg cells were examined. The results showed that the IC50 of TP was19. 6 nmol·L~(-1) in spleen lymphocytes. TP inhibited the secretion of IL-2 and IL-10 and induced the expression of SOCS-1/3 mRNA in spleen lymphocytes at the dosage of 2. 5 and 5 nmol·L~(-1) after 24 h in vitro. Administration of TP at dosage of 500 µg·kg-1 had no significant spleen toxicity in vivo. TP treatment increased the percentage of Th17 cells after 12 h and inhibited the proportion of Treg cells after 12 and 24 h. In conclusion,TP reduced the secretion of IL-2 and IL-10 through SOCS-1/3 signaling pathway,thereby induced the percentage of Th17 cells and inhibited the percentage of Treg cells.

Treatment with 6-Gingerol Regulates Dendritic Cell Activity and Ameliorates the Severity of Experimental Autoimmune Encephalomyelitis.

SCOPE: Multiple sclerosis (MS) is an inflammatory demyelinating autoimmune disorder, with increasing incidence worldwide but unknown etiology. 6-Gingerol (6-GIN), a major dietary compound found in ginger rhizome, has immunomodulatory activity. However, its role in autoimmune diseases, as well as the underlying mechanisms, are unclear. In this study, it is evaluated if 6-GIN can effectively ameliorate the clinical disease severity of experimental autoimmune encephalomyelitis, an animal model of MS. METHODS AND RESULTS: Clinical scores of experimental autoimmune encephalomyelitis (EAE) mice are recorded daily. Inflammation of periphery and neuroinflammation of EAE mice are determined by flow cytometry analysis, ELISA, and histopathological analysis, and results show that 6-GIN significantly inhibits inflammatory cell infiltration from the periphery into the central nervous system and reduces neuroinflammation and demyelination. Flow cytometry analysis, ELISA, and quantitative PCR show that 6-GIN could suppress lipolysaccharide-induced dendritic cell (DC) activation and induce the tolerogenic DCs. Immunoblot analysis reveals that the phosphorylation of nuclear factor-κB and mitogen-activated protein kinase, two critical regulators of inflammatory signaling, are significantly inhibited in 6-GIN-treated DCs. CONCLUSION: The results of this study demonstrate that 6-GIN has significant potential as a novel anti-inflammatory agent for the treatment of autoimmune diseases such as MS via direct modulatory effects on DCs.

Astragalus membranaceus improves therapeutic efficacy of asthmatic children by regulating the balance of Treg/Th17 cells.

Astragalus membranaceus may be a potential therapy for childhood asthma but its driving mechanism remains elusive. The main components of A. membranaceus were identified by HPLC. The children with asthma remission were divided into two combination group (control group, the combination of budesonide and terbutaline) and A. membranaceus group (treatment group, the combination of budesonide, terbutaline and A. membranaceus). The therapeutic results were compared between two groups after 3-month therapy. Porcine peripheral blood mononuclear cells (PBMCs) were isolated from venous blood by using density gradient centrifugation on percoll. The levels of FoxP3, EGF-ß, IL-17 and IL-23 from PBMCs and serum IgE were measured. The relative percentage of Treg/Th17 cells was determined using flow cytometry. The main components of A. membranaceus were calycosin-7-O-glucoside, isoquercitrin, ononin, calycosin, quercetin, genistein, kaempferol, isorhamnetin and formononetin, all of which may contribute to asthma therapy. Lung function was significantly improved in the treatment group when compared with a control group (P < 0.05). The efficacy in preventing the occurrence of childhood asthma was higher in the treatment group than the control group (P < 0.05). The levels of IgE, IL-17 and IL-23 were reduced significantly in the treatment group when compared with the control group, while the levels of FoxP3 and TGF-ß were increased in the treatment group when compared with the control group (P < 0.05). A. membranaceus increased the percentage of Treg cells and reduced the percentage of Th17 cells. A. membranaceus is potential natural product for improving the therapeutic efficacy of combination therapy of budesonide and terbutaline for the children with asthma remission by modulating the balance of Treg/Th17 cells.

Berberine attenuates arthritis in adjuvant-induced arthritic rats associated with regulating polarization of macrophages through AMPK/NF-кB pathway.

Berberine (BBR) is a traditional folk medicine with excellent anti-inflammatory properties. This study aimed to investigate the anti-arthritic effects of BBR in adjuvant arthritis (AA) in rats and its regulatory role in the polarization of macrophages. Rats were immunized with Complete Freund's Adjuvant (CFA), and then BBR (40, 80, 160 mg/kg) was administered orally for 14 days. BBR significantly reduced paw swelling and arthritis global assessment as well as alleviated joint destruction and inflammatory cell infiltration. The index of the thymus and thymocyte proliferation were significantly reduced by BBR. Moreover, BBR treatment restrained the phagocytic function of macrophages and restored the balance of M1/M2 by reducing the levels of M1 cytokines (tumour necrosis factor-α, interleukin-1ß, and interleukin-6), increasing the levels of M2 cytokines (interleukin-10 and transforming growth factor-ß1), increasing the expression of arginase 1(Arg1) (M2 marker) and decreasing the expression of inducible nitric oxide synthase (iNOS) (M1 marker). BBR also downregulated the ratio of Th17/Treg cells. Further research on the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)/nuclear factor κB (NF-κB) pathway found that BBR upregulated the activity of AMPK, while it downregulated the expression of phospho-RelA (p-p65), phospho-NF-kappa-B inhibitor alpha (p-IκBα) and cyclooxygenase (COX)-2. Therefore, our findings suggest BBR has significantly therapeutic effects in AA rats by regulating the polarization of macrophages through the AMPK/NF-кB pathway.

Correlation analysis of Treg/Th17 cells and related cytokines in patients with psoriasis vulgaris.

OBJECTIVE: To investigate potential differences in circulating levels of T regulatory (Treg)/T helper 17 (Th17) cells, related inflammatory cytokines and specific transcription factors in healthy individuals and patients with psoriasis conforming to one of three Traditional Chinese Medicine (TCM) syndromes: blood-heat syndrome (BHS), blood-stasis syndrome (BSS) and blood-dryness syndrome (BDS). METHODS: Sixty-seven patients with psoriasis were recruited and assigned to one of three corresponding TCM syndrome groups: BHS (n = 40), BSS (n = 14) and BDS (n = 13 patients). The control group comprised 21 healthy individuals. The circulating levels of Treg/Th17 cells in peripheral blood were assessed using flow cytometry; the levels of inflammatory cytokines interleukin (IL)-10 and tumor necrosis factor (TNF)-α by enzyme-linked immunosorbent assay; and the mRNA expression of T cell-specific transcription factors retinoic acid-related orphan receptor γt (RORγt) and forkhead box P3 (Foxp3) by quantitative real-time PCR. RESULTS: The ratio of Th17 cells and the levels of TNF-α and RORγt were all significantly higher in the BHS and BSS groups than the control group (P < 0.05), while the ratio of Treg cells and the levels of IL-10 and Foxp3 mRNA in the BHS group were significantly lower compared with the control group (P < 0.05). No significant differences were seen between the BSS group and the control group. The ratio of Th17 cells and the levels of TNF-α and RORγt in the BDS group were not significantly different from those of the control group; however, the ratio of Treg cells and the levels of IL-10 and Foxp3 were all lower than those in the healthy controls (P < 0.05). CONCLUSION: Compared with healthy individuals, the ratio of Th17 cells and the levels of related cytokines were higher, while the ratio of Treg cells and the levels of related cytokines were lower, in the peripheral blood of psoriasis/BHS patients; corresponding results for the BSS and BDS groups also showed differences. We propose that patterns of differentiation of immunological cells in psoriasis patients are reflected in corresponding TCM blood syndromes.

Discovery of a potent orally bioavailable retinoic acid receptor-related orphan receptor-gamma-t (RORγt) inhibitor, S18-000003.

The retinoic acid receptor-related orphan receptor-gamma-t (RORγt) is the master transcription factor responsible for regulating the development and function of T-helper 17 (Th17) cells, which are related to the pathology of several autoimmune disorders. Therefore, RORγt is an attractive drug target for such Th17-mediated autoimmune diseases. A structure-activity relationship (SAR) study of lead compound 1 yielded a novel series of RORγt inhibitors, represented by compound 6. Detailed SAR optimization, informed by X-ray cocrystal structure analysis, led to the discovery of a potent orally bioavailable RORγt inhibitor 25, which inhibited IL-17 production in the skin of IL-23-treated mice by oral administration.

Carnosol Modulates Th17 Cell Differentiation and Microglial Switch in Experimental Autoimmune Encephalomyelitis.

Medicinal plants as a rich pool for developing novel small molecule therapeutic medicine have been used for thousands of years. Carnosol as a bioactive diterpene compound originated from Rosmarinus officinalis (Rosemary) and Salvia officinalis, herbs extensively applied in traditional medicine for the treatment of multiple autoimmune diseases (1). In this study, we investigated the therapeutic effects and molecule mechanism of carnosol in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Carnosol treatment significantly alleviated clinical development in the myelin oligodendrocyte glycoprotein (MOG35-55) peptide-induced EAE model, markedly decreased inflammatory cell infiltration into the central nervous system and reduced demyelination. Further, carnosol inhibited Th17 cell differentiation and signal transducer and activator of transcription 3 phosphorylation, and blocked transcription factor NF-κB nuclear translocation. In the passive-EAE model, carnosol treatment also significantly prevented Th17 cell pathogenicity. Moreover, carnosol exerted its therapeutic effects in the chronic stage of EAE, and, remarkably, switched the phenotypes of infiltrated macrophage/microglia. Taken together, our results show that carnosol has enormous potential for development as a therapeutic agent for autoimmune diseases such as MS.

Celastrol mediates Th17 and Treg cell generation via metabolic signaling.

A T helper 17 (Th17) cell/regulatory T (Treg) cell imbalance is involved in many immune disorders and diseases. Celastrol, a Chinese herbal compound that has anti-inflammatory and immunosuppressive properties, has been indicated to suppress T cell proliferation and Th17 cell induction, while facilitating Forkhead box P3 (Foxp3) expression and Treg cell generation. In this study, we explored the impact and mechanism of celastrol on Th17 cell/induced Treg (iTreg) cell induction. CD4+CD25- T cells were purified, stimulated with anti-CD3 and anti-CD28 antibodies, and polarized in vitro to generate Th17 or iTreg cells in the presence or absence of celastrol. Initially, we determined that Interleukin (IL)-17 expression by celastrol-treated Th17 was significantly decreased compared with untreated cells; however, the frequency of Foxp3+ cells was increased in celastrol-treated cells. We verified that celastrol inhibited phospho-STAT3 expression in cultured Th17 cells and up-regulated phospho-STAT5 expression in iTreg cells. Furthermore, T cells treated with celastrol were more likely to participate in FAO metabolism instead of glycolysis. Celastrol suppressed the expression of glucose transporter, Glut1, and the rate-limiting enzyme, HK2, in addition to mTOR, HIF-1α, c-Myc and Akt expression in Th17 cells. Conversely, celastrol promoted FAO of lipids by up-regulating CPT1A and AMPKα expression in iTreg cells. Our results suggest that celastrol suppresses Th17 cell induction, while promoting the generation of iTreg cells. We found that celastrol inhibits glycolysis in Th17 cells and promotes FAO by iTreg cells, suggesting that celastrol could mediate the metabolism of Th17 and iTreg cells.

Discovery and Characterization of CD12681, a Potent RORγ Inverse Agonist, Preclinical Candidate for the Topical Treatment of Psoriasis.

With possible implications in multiple autoimmune diseases, the retinoic acid receptor-related orphan receptor RORγ has become a sought-after target in the pharmaceutical industry. Herein are described the efforts to identify a potent RORγ inverse agonist compatible with topical application for the treatment of skin diseases. These efforts culminated in the discovery of N-(2,4-dimethylphenyl)-N-isobutyl-2-oxo-1-[(tetrahydro-2H-pyran-4-yl)methyl]-2,3-dihydro-1H-benzo[d]imidazole-5-sulfonamide (CD12681), a potent inverse agonist with in vivo activity in an IL-23-induced mouse skin inflammation model.

PKCε promotes human Th17 differentiation: Implications in the pathophysiology of psoriasis.

PKCε is implicated in T cell activation and proliferation and is overexpressed in CD4+ -T cells from patients with autoimmune Hashimoto's thyroiditis. Although this might induce the suspicion that PKCε takes part in autoimmunity, its role in the molecular pathophysiology of immune-mediated disorders is still largely unknown. We studied PKCε expression in circulating CD4+ -T cells from patients with psoriasis, a skin disorder characterized by an increased amount of Th17 cells, a CD4+ subset that is critical in the development of autoimmunity. Although the mechanisms that underlie Th17 differentiation in humans are still unclear, we here show that: (i) PKCε is overexpressed in CD4+ -T cells from psoriatic patients, and its expression positively correlates with the severity of the disease, being reduced by effective phototherapy; (ii) PKCε interacts with Stat3 during Th17 differentiation and its overexpression results in an enhanced expression of Stat3 and pStat3(Ser727); iii) conversely, when PKCε is forcibly downregulated, CD4+ -T cells show lower levels of pStat3(Ser727) expression and defective in vitro expansion into the Th17-lineage. These data provide a novel insight into the molecular mechanisms of Th17 cell polarization that is known to play a crucial role in autoimmunity, pinpointing PKCε as a potential target in Th17-mediated diseases.