Discovery of Orally Available Retinoic Acid Receptor-Related Orphan Receptor γ-t/Dihydroorotate Dehydrogenase Dual Inhibitors for the Treatment of Refractory Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) is a multifactorial autoimmune disease, representing a major clinical challenge. Herein, a strategy of dual-targeting approach employing retinoic acid receptor-related orphan receptor γ-t (RORγt) and dihydroorotate dehydrogenase (DHODH) was proposed for the treatment of IBD. Dual RORγt/DHODH inhibitors are expected not only to reduce RORγt-driven Th17 cell differentiation but also to mitigate the expansion and activation of T cells, which may enhance anti-inflammatory effects. Starting from 2-aminobenzothiazole hit 1, a series of 2-aminotetrahydrobenzothiazoles were discovered as potent dual RORγt/DHODH inhibitors. Compound 14d stands out with IC50 values of 0.110 µM for RORγt and of 0.297 µM for DHODH. With acceptable mouse pharmacokinetic profiles, 14d exhibited remarkable in vivo anti-inflammatory activity and dose-dependently alleviated the severity of dextran sulfate sodium (DSS)-induced acute colitis in mice. Taken together, the present study provides a novel framework for the development of therapeutic agents for the treatment of IBD.

The effect of ginger supplementation on some immunity and inflammation intermediate genes expression in patients with active Rheumatoid Arthritis.

OBJECTIVE: Rheumatoid Arthritis (RA) is an autoimmune disease. The aim of this study was to investigate the effect of ginger supplementation on the expression of some immunity and inflammation intermediate genes in patients who suffer from RA. METHODS: In this randomized double-blind placebo-controlled clinical trial, seventy active RA patients were allocated randomly into two groups who either received 1500 mg ginger powder or placebo daily for 12 weeks. Disease activity score and gene expression of NF-κB, PPAR-γ, FoxP3, T-bet, GATA-3, and RORγt as immunity and inflammation intermediate factors were measured using quantitative real-time PCR before and after the intervention. RESULTS: After the intervention, FoxP3 genes expression increased significantly within ginger group and between the two groups (P-value = 0.02). Besides, T-bet and RORγt genes expression decreased significantly between the two groups (P-value < 0.05). In ginger group, PPAR-γ genes expression increased significantly (P-value = 0.047) but the difference between the two groups wasn't statistically significant (P-value = 0.12). The reduction in disease activity score was statistically significant within ginger group and between the two groups after the intervention. CONCLUSION: It seems that ginger can improve RA by decreasing disease manifestations via increasing FoxP3 genes expression and by decreasing RORγt and T-bet genes expression.

Pro-inflammatory effects of the Th1 chemokine CXCL10 in acquired aplastic anaemia.

CXCL10/IFN-γ-induced protein 10 (IP-10) and its corresponding receptor CXCR3 have long been considered to be involved in the pathophysiology of type 1 T (Th1) cell-orientated autoimmune diseases. However, the exact role of CXCL10 in the pathogenesis of aplastic anaemia (AA) has not been thoroughly studied. The aim of our study was to evaluate the plasma level of CXCL10 and its effects on CD4+ T cell differentiation in AA. In our study, we found that an elevated plasma level of CXCL10 was negatively correlated with platelet, absolute neutrophil and reticulocyte counts, while it was positively correlated with the proportion of lymphocytes in white blood cells in AA patients. To confirm the pro-inflammatory effects of CXCL10 in AA, we isolated CD4+ T cells and evaluated the function of CXCL10 in CD4+ T cell differentiation. In vitro stimulation experiments further revealed the pro-inflammatory role of CXCL10 in AA, partially by promoting the secretion of interferon (IFN)-γ and IL-17. In addition, CXCL10 significantly skewed CD4+ T cell differentiation to Th1 cells and T helper 17 (Th17) cells in AA patients, while it inhibited the differentiation of type 2 T (Th2) cells only in controls. The mRNA expression of transcription factors representative of T cell differentiation was detected by RT-PCR. Consistently, our results showed that after CXCL10 treatment, the expression of T-bet and RORγt was significantly enhanced, while the expression of GATA3 was inhibited. In conclusion, our results indicated that CXCL10, a pro-inflammatory chemokine, might be involved in the abnormal immune response in AA.

Gut Microbiota Promote Angiotensin II-Induced Arterial Hypertension and Vascular Dysfunction.

BACKGROUND: The gut microbiome is essential for physiological host responses and development of immune functions. The impact of gut microbiota on blood pressure and systemic vascular function, processes that are determined by immune cell function, is unknown. METHODS AND RESULTS: Unchallenged germ-free mice (GF) had a dampened systemic T helper cell type 1 skewing compared to conventionally raised (CONV-R) mice. Colonization of GF mice with regular gut microbiota induced lymphoid mRNA transcription of T-box expression in T cells and resulted in mild endothelial dysfunction. Compared to CONV-R mice, angiotensin II (AngII; 1 mg/kg per day for 7 days) infused GF mice showed reduced reactive oxygen species formation in the vasculature, attenuated vascular mRNA expression of monocyte chemoattractant protein 1 (MCP-1), inducible nitric oxide synthase (iNOS) and NADPH oxidase subunit Nox2, as well as a reduced upregulation of retinoic-acid receptor-related orphan receptor gamma t (Rorγt), the signature transcription factor for interleukin (IL)-17 synthesis. This resulted in an attenuated vascular leukocyte adhesion, less infiltration of Ly6G(+) neutrophils and Ly6C(+) monocytes into the aortic vessel wall, protection from kidney inflammation, as well as endothelial dysfunction and attenuation of blood pressure increase in response to AngII. Importantly, cardiac inflammation, fibrosis and systolic dysfunction were attenuated in GF mice, indicating systemic protection from cardiovascular inflammatory stress induced by AngII. CONCLUSION: Gut microbiota facilitate AngII-induced vascular dysfunction and hypertension, at least in part, by supporting an MCP-1/IL-17 driven vascular immune cell infiltration and inflammation.

Oxidized Low-Density Lipoprotein (OxLDL)-Treated Dendritic Cells Promote Activation of T Cells in Human Atherosclerotic Plaque and Blood, Which Is Repressed by Statins: microRNA let-7c Is Integral to the Effect.

BACKGROUND: Activated T cells and dendritic cells (DCs) are colocalized in atherosclerotic plaques in association with plaque rupture. Oxidized low-density lipoprotein (oxLDL) promotes immune activation and inflammation. We studied the effects of statins (atorvastatin and simvastatin) on human DC maturation and T-cell activation. METHODS AND RESULTS: Human peripheral blood monocytes were differentiated to DCs and stimulated with oxLDL. T cells were isolated from carotid endarterectomy specimens from patients undergoing carotid endarterectomy or from healthy individuals. Naïve T cells were cocultured with pretreated DCs. The effects of statin were studied. OxLDL induced DC maturation and T-cell activation. OxLDL induced atherogenic heat shock proteins (HSP) 60 and 90 and decreased potentially atheroprotective heat shock protein 27, effects restored by atorvastatin. T cells exposed to oxLDL-treated DCs produced interferon-γ and interleukin (IL)-17. Atorvastatin and simvastatin suppressed the DC maturation showing lower expression of CD80, CD83, and CD86, and limited their production of tumor necrosis factor-α, IL-1ß and IL-6, and increased transforming growth factor-ß and IL-10 secretion. Statin-treated DCs inhibited Th1 and/or Th17 polarization by downregulation of transcriptional factors T-bet and RORγt expression, and induced T regulatory cells with IL-10 production. OxLDL-induced miRNA let7c and phosphorylation of Akt and ERK were repressed by statins. Let-7c had a pivotal role in mediating effect of oxLDL. Experiments on T cells derived from carotid atherosclerotic plaques or healthy individuals showed similar results. CONCLUSIONS: Statins repress human DC maturation induced by oxLDL, limit T-cell activation, and repress an atherogenic heat shock protein profile and promote induction of T regulatory cells. MicroRNA let-7c is integral to the effects.

Inhibiting the Th17/IL-17A-related inflammatory responses with digoxin confers protection against experimental abdominal aortic aneurysm.

OBJECTIVE: T helper 17 cells and interleukin-17A have been implicated in the progression of abdominal aortic aneurysm (AAA). Retinoic acid-related orphan receptor gamma thymus, the master transcription factor of T helper 17 cell differentiation, is selectively antagonized by digoxin. However, the effect of antagonizing retinoic acid-related orphan receptor gamma thymus on AAA has not been investigated. APPROACH AND RESULTS: We used human aortic sample analysis and 2 different experimental AAA models: (a) Angiotensin II (Ang II)-induced ApoE(-/-) male mice (Ang II/APOE model) and (b) porcine pancreatic elastase perfusion C57BL/6 mice (porcine pancreatic elastase/C57 model). In the Ang II/APOE model, all mice (n=80) were divided into 4 groups: sham group (saline+0.5% dimethyl sulfoxide treatment), control group (Ang II+0.5% dimethyl sulfoxide treatment), low-dose group (Ang II+low-dose digoxin, 20 µg/d per mouse), and high-dose group (Ang II+high-dose digoxin, 40 µg/d per mouse). All treatments began on day 0 after surgery. Efficacy was determined via aortic diameter and systolic blood pressure measurements, histopathology and protein expression, and flow cytometry analysis when euthenized. Human aortic tissue analysis showed that both interleukin-17A and retinoic acid-related orphan receptor gamma thymus increased in AAA tissues. The low-dose and high-dose groups had AAA incidences of 60% and 35%, respectively, compared with 70% in the control group. The T helper 17- and interleukin-17A-related inflammatory responses were dose-dependently attenuated by digoxin treatment. Digoxin was also highly effective in the porcine pancreatic elastase/C57 model. CONCLUSIONS: Digoxin attenuates experimental AAA progression in a model-independent manner. Antagonizing retinoic acid-related orphan receptor gamma thymus activity by digoxin may become a novel strategy for nonsurgical AAA treatment.

Effects of probiotic yogurt on fat distribution and gene expression of proinflammatory factors in peripheral blood mononuclear cells in overweight and obese people with or without weight-loss diet.

OBJECTIVES: The purpose of this study was to investigate whether probiotics had an effect on proinflammatory markers and cytokines in overweight and obese individuals and whether they could have synergistic effects with weight-loss diets. METHODS: A total of 75 healthy overweight and obese individuals completed this randomized doubled-blind controlled clinical trial. Participants were randomly assigned to groups consuming regular yogurt with a low-calorie diet (LCD, RLCD; n = 25) or receiving probiotic yogurt with LCD (PLCD; n = 25) or consuming probiotic yogurt without LCD (PWLCD; n = 25) for 8 weeks. The pribiotic regimen contained 200 g/day yogurt, enriched by Lactobacillus acidophilus La5, Bifidobacterium BB12, and Lactobacillus casei DN001 10(8) colony-forming units/g. Body fat percentage, high-sensitive C-reactive protein (hs-CRP), tumor necrosis factor-alpha (TNF-α), leptin, and mRNA levels of inflammation-related genes (TNF-α and RAR-related orphan receptor gamma [ROR-γt]) in peripheral blood mononuclear cells (PBMCs) were measured. RESULTS: A reduction in body mass index (BMI), fat percentage, and leptin level was observed that was more obvious in groups who received the weight-loss diet with probiotic yogurt. Reduction in the gene expression of ROR-γt was significant in the PLCD group (p < 0.001). The expression of TNF-α did not change among all groups after intervention. The mean concentration of leptin was significantly decreased in all groups after the dietary intervention, but the mean changes in leptin level in the PLCD group was more prominent compared to the other two groups (-2.38, p < 0.001 [PLCD] vs -1.75, p = 0.002 [RLCD] and -0.55 ng/mL, p = 0.12 [PWLCD]). The reduction in serum levels of hs-CRP was more evident in the PWLCD group compared to the PLCD and RLCD groups after the 8-week intervention (-3.4, p = 0.03 vs -1.76, p < 0.001 and -2.98 pg/mL, p < 0.001, respectively). CONCLUSION: Our results suggested that the weight-loss diet and probiotic yogurt had synergistic effects on T-cells subset specific gene expression in PBMCs, fat percentage, and body weight among overweight and obese individuals.

Staphylococcal enterotoxin B induced expression of IL-17A in nasal epithelial cells and its association with pathogenesis of nasal polyposis.

Interleukin (IL)-17A is a highly inflammatory cytokine and is known to be produced by Th17 cells. The importance of IL-17A expression in nasal epithelial cells is not well understood. The goal of this study is to explore the expression of IL-17A in nasal epithelial cells in vivo and in vitro. IL-17A and staphylococcal enterotoxin B (SEB) were detected by immunofluorescence (IF) in nasal epithelial cells of control mucosa (n = 10) and nasal polyps (n = 20). Expression of IL-17A, RORC, IL-6, and TGF-ß1 was also measured by RT-PCR in the tissue of control nasal mucosa (n = 10) and nasal polyps (n = 20). IL-17A expression was evaluated in the human nasal epithelial cells after SEB stimulation. Finally, IL-17A expression was demonstrated by immunohistochemistry and IF following intranasal SEB instillation in mice. Expression of IL-17A in nasal epithelial cells was higher in nasal polyps compared to control mucosa. There was a significant correlation between IL-17A and SEB detection in nasal polyps using IF. SEB increased IL-17A expression in human nasal epithelial cells, and in epithelial cells of SEB instilled mice. In conclusion, SEB exposure of nasal epithelial cells induces the enhanced expression of IL-17A. SEB may be involved in pathogenesis of nasal polyps by enhancing IL-17A expression in epithelial cells in nasal polyps.

Oral administration of all-trans retinoic acid suppresses experimental periodontitis by modulating the Th17/Treg imbalance.

BACKGROUND: A T-helper 17 (Th17)/regulatory T (Treg) imbalance has been suggested recently to play a role in the development of periodontitis. All-trans retinoic acid (ATRA) has been reported to modulate Th17/Treg imbalances in some diseases. However, the effect of ATRA on periodontitis remains unknown. This study observes the effect of ATRA on Th17/Treg imbalance modulation in experimental periodontitis. METHODS: Experimental periodontitis was induced in mice by oral infection with Porphyromonas gingivalis (P. gingivalis). ATRA was orally administered every other day. Alveolar bone resorption (ABR) was estimated by measuring the distance from the cemento-enamel junction to the alveolar bone crest. CD4(+) T-cell subsets in the cervical lymph nodes (CLNs) and spleen were analyzed by flow cytometry. Th17/Treg cell-related cytokine messenger ribonucleic acid expression was quantified by real-time reverse transcription-polymerase chain reaction. RESULTS: The present data shows that ATRA suppressed ABR and inhibited inflammatory cell infiltration into periodontal tissues. These effects were closely associated with reduced CD4(+) retinoid-related orphan receptor γτ(+) cells and increased CD4(+) forkhead box P3(+) cells in the CLNs. Furthermore, ATRA downregulated interleukin (IL)-17A expression and upregulated IL-10 and transforming growth factor-ß1 expression in both the CLNs and P. gingivalis-infected gingival tissues. CONCLUSIONS: These results suggest that ATRA modulation of the Th17/Treg imbalance provides protection against periodontitis by enhancing Treg cell activation and inhibiting Th17 cell activation. These results indicate the potential for clinical prevention of periodontitis.

Digoxin attenuates acute cardiac allograft rejection by antagonizing RORγt activity.

BACKGROUND: Th17 responses have been suggested to participate in the pathogenesis of acute allograft rejection. RORγt is the master transcription factor that controls Th17 cell differentiation and expansion. However, little is known about the effect that antagonizing RORγt activity may have on acute cardiac allograft rejection. METHODS: A model of heterotopic murine cardiac transplantation with total allomismatch (BALB/c to B6 mice) was used. Digoxin, which was recently identified as a specific antagonist of RORγt, was injected intraperitoneally daily (40 µg) starting 1 day after cardiac transplantation. The severity of rejection was determined by histology. The mRNA expression levels of cytokines and transcription factors in the grafts were measured by quantitative real-time PCR. The proportion and number of T-cell subpopulations in the allografts and spleens were analyzed by flow cytometry. In vitro, the effect of digoxin on allogeneic responses and the interleukin (IL)-6-mediated conversion of regulatory T cells (Treg) into Th17 cells were investigated. RESULTS: Treatment with digoxin significantly prolonged cardiac allograft survival compared with dimethyl sulfoxide treatment (mean survival time, 16.5±2.2 versus 8.1±0.7 days; P<0.01). Treatment with digoxin also markedly suppressed the mRNA expression levels of IL-17A, IL-17F, and granulocyte-macrophage colony-stimulating factor, reduced the number of Th17 cells, and induced Treg expansion in the allografts. In vitro, treatment with digoxin did not inhibit the proliferation of T cells in a mixed lymphocyte reaction, but it did inhibit the IL-6-mediated conversion of Tregs into Th17 cells. CONCLUSIONS: RORγt may be a promising therapeutic target to attenuate acute cardiac allograft rejection. Digoxin therefore provides a molecular basis for the design of novel immunosuppressive agents.