Liver X receptor activation promotes differentiation of regulatory T cells

The nuclear receptor Liver X Receptor (LXR) is a ligand-activated transcription factor that has been implicated in control of chronic inflammation by downregulating pro-inflammatory T cell responses. An impaired function of regulatory T cells, a subset of CD4+ T cells with a crucial role in maintaining lymphocytes homeostasis and immune regulation, is frequently observed in chronic inflammatory diseases. We observed that pharmacological activation of LXR in T cells not only resulted in a thorough suppression of Th1 and Th17 polarization in vitro, but also significantly induced regulatory T cells (Treg) cell differentiation in a receptor-specific fashion. In line with this, systemic LXR activation by oral treatment of mice with the LXR agonist GW3965 induced gut-associated regulatory T cells in vivo. Importantly, such LXR-activated Tregs had a higher suppressive capacity in functional in vitro coculture assays with effector T cells. Our data thus point towards a dual role of LXR-mediated control of inflammation by suppression of pro-inflammatory T cells and reciprocal induction of regulatory T cells.

Therapeutic Effect of Exogenous Truncated IK Protein in Inflammatory Arthritis

Inhibitor K562 (IK) protein was first isolated from the culture medium of K562, a leukemia cell line. It is known to be an inhibitory regulator of interferon-γ-induced major histocompatibility complex class (MHC) II expression. Previously, we found that transgenic (Tg) mice constitutively expressing truncated IK (tIK) showed reduced numbers of pathogenic Th1 and Th17 cells, which are known to be involved in the development of rheumatoid arthritis (RA). Here, we investigated whether exogenous tIK protein has a therapeutic effect in arthritis in disease models and analyzed its mechanism. Exogenous tIK protein was produced in an insect expression system and applied to the collagen antibody-induced arthritis (CAIA) mouse disease model. Injection of tIK protein alleviated the symptoms of arthritis in the CAIA model and reduced Th1 and Th17 cell populations. In addition, treatment of cultured T cells with tIK protein induced expression of A20, a negative regulator of nuclear factor-κB (NFκB)-induced inflammation, and reduced expression of several transcription factors related to T cell activation. We conclude that exogenous tIK protein has the potential to act as a new therapeutic agent for RA patients, because it has a different mode of action to biopharmaceutical agents, such as tumor necrosis factor antagonists, that are currently used to treat RA.

Elevation of Circulating Th17/Th22 Cells Exposed to Low-Level Formaldehyde and Its Relevance to Formaldehyde-Induced Occupational Allergic Contact Dermatitis

OBJECTIVES

The aim of this study was to investigate the effects of formaldehyde exposure on Th17 and Th22 cells and its relevance to human occupational allergic contact dermatitis (OACD).

METHODS

Circulating IL17-/IL22-secreting cells and serum IL17/IL22 levels in formaldehyde-exposed workers at Occupational Exposure Limit and nonexposed controls were assessed.

RESULTS

The IL17 and IL22 cell population were detected in both CD3CD8 and CD3CD8 cells. The percentages of circulating IL17 and IL22 T cells in the workers with and without ACD history were all elevated, which were more remarkable in the ones with ACD history. Serum levels of IL17 and IL22 between the workers and controls were not significantly different.

CONCLUSIONS

Low-level formaldehyde exposure may increase circulating IL17-/IL22-producing T cells (CD8 and CD8), possibly involved in the development of human OACD. But it may not alter serum levels of IL17/IL22 before the appearance of OACD symptoms.

Regulatory effect of baicalin on the imbalance of Th17/Treg responses in mice with allergic asthma

ETHNOPHARMACOLOGY RELEVANCE

Baicalin, a flavonoid compound, was isolated from traditional Chinese medicine Scutellaria baicalensis Georgi. The study aimed to explore the regulatory effect of baicalin on immunological balance of Th17/Treg responses and the possible mechanisms in mice with allergic asthma.

MATERIALS AND METHODS

Mice were sensitized and challenged with OVA+LPS by intranasal instillation, and were intragastrically treated with baicalin from days 22-36 after sensitization. The organ coefficient of lung was determined. Immunoglobulin E (IgE) level in serum and cytokine IL-17A, IL-6, IL-10 levels in bronchoalveolar lavage fluid (BALF) were measured by ELISA. Histological changes in lung and airway tissues were observed by hematoxylin and eosin (H&E) and periodic acid-Schiff staining (PAS). The expressions of signal transducer and activator of transcription 3 (STAT3) and forkhead box P3 (FOXP3) in lung tissues were evaluated by immunohistochemistry and western blot methods.

RESULTS

Baicalin obviously decreased OVA+LPS-induced organ coefficient of lung, inhibited serum IgE and BALF IL-7A and IL-6 secrection, promoted BALF IL-10 secrection in a dose-dependent manner. Histological studies demonstrated that baicalin significantly alleviated OVA+LPS-induced inflammatory responses and mucus secretion in lung and airway tissues. Immunohistochemistry and western blot studies showed that baicalin substantially suppressed STAT3 expression and promoted FOXP3 expression in lung tissues of mice.

CONCLUSIONS

These findings suggest that baicalin effectively protects against OVA+LPS-induced allergic asthma in mice by regulating the immunological imbalance of Th17/Treg responses.

Anemoside A3 ameliorates experimental autoimmune encephalomyelitis by modulating T helper 17 cell response

Anemoside A₃ (AA3) is a natural triterpenoid glycoside isolated from the root of Pulsatilla chinensis (Bunge) Regel. We previously showed that AA3 exhibits cognitive-enhancing and neuroprotective properties. In the present study, we demonstrated that AA3 modulates inflammatory responses by regulating prostaglandin E receptor 4 signaling. Because prostaglandin E receptor 4 is involved in the pathophysiology of experimental autoimmune encephalomyelitis (EAE), an animal model of human multiple sclerosis (MS), we assessed the beneficial effect of AA3 in EAE mice. AA3 treatment significantly reduced clinical severity and inflammatory infiltrates in the spinal cord of EAE mice. In vitro studies revealed that AA3 inhibited the T cell response toward the encephalitogenic epitope of myelin oligodendrocyte glycoprotein (MOG). AA3 significantly downregulated the expressions of certain Th1 and Th17 cytokines in activated T cells re-stimulated by MOG. Moreover, AA3 inhibited the activation of STAT4 and STAT3, which are the transcription factors pivotal for Th1 and Th17 lineage differentiation, respectively, in activated T cells. Pharmacological analysis further suggested that AA3 reduced Th17 cell differentiation and expansion. In conclusion, AA3 exerts an immunomodulatory effect in EAE, demonstrating its potential as a therapeutic agent for MS in humans.

Therapy with omeprazole modulates regulatory T cell/T helper 17 immune response in children with duodenal ulcers

The purpose of this study was to determine the effect of omeprazole on the regulatory T cell (Treg) and T helper 17 (Th17)-mediated response in patients with duodenal ulcers (DUs). DU patients were randomly divided into omeprazole and colloid bismuth subcitrate treatment groups. The ratios of Th17 and Treg in peripheral blood mononuclear cells (PBMCs) were measured. Cytokine production and Foxp3⁺- and RORγt-positive cells were detected. The expressions of STAT3, p-STAT3, STAT5 and p-STAT5 were detected by Western blot. The results showed that DU patients had an imbalanced Treg/Th17 response, as reflected by the higher IL-17 level and Th17 ratio and lower IL-10 level and Treg proportion in serum compared with those in the healthy volunteers. The administration of omeprazole to the patients significantly increased Treg and IL-10 levels and reduced Th17 and IL-17 levels. Omeprazole markedly increased the number of Foxp3-positive cells, decreased the number of RORγt-positive cells and restored the balanced ratio of IL-10/IL-17 in the ulcer tissue. Interestingly, we observed a negative correlation between the ratios of Treg/Th17 and the pathological scores in damaged tissues. Of note, H. pylori-infected PBMCs showed decreased Treg and an increased Th17 proportion, which could be reversed by omeprazole. Finally, omeprazole increased the expression of p-STAT5 and reduced the level of p-STAT3 without any effects on the total expression of STAT5 and STAT3. Our data suggest that omeprazole treatment restores the equilibrium of the Treg/Th17-mediated response in DU patients. Moreover, the modulation of p-STAT3 and p-STAT5 expression by omeprazole induced balanced polarisation of Treg/Th17.

Sodium selenite ameliorates dextran sulfate sodium-induced chronic colitis in mice by decreasing Th1, Th17, and γδT and increasing CD4(+)CD25(+) regulatory T-cell responses

AIM

To assess the effect of sodium selenite on the severity of dextran sulfate sodium (DSS)-induced colitis in C57BL/6 mice.

METHODS

Mice were randomly divided into four groups (n = 10/group): normal group, selenium (Se) group, chronic colitis group, and Se + chronic colitis group. The mice were sacrificed on day 26. Survival rates, clinical symptoms, colon length, and histological changes were determined. The percentages and absolute numbers of immune system cells in the lamina propria lymphocytes (LPL) of the colon, the expression of mRNA in colon tissue, and the concentrations of Th1, Th17, and Treg cytokines in LPL from the large intestine, were measured.

RESULTS

Se significantly ameliorated the symptoms of colitis and histological injury (P < 0.05 each), increasing the proportions of neutrophils and CD4⁺ CD25⁺ T cells (P < 0.05 each) and decreasing the proportions of γδT cells, CD4⁺, CD4⁺CD44⁺, and CD4⁺ CD69⁺ T cells in LPL (P < 0.05 each). Moreover, Se reduced the expression of IL-6, IFN-γ, IL-17A, IL-21, T-bet, and RORγt (P < 0.05 each), but enhanced the expression of IL-10 and Foxp3 (P < 0.05 each).

CONCLUSION

These results suggest that Se protects against DSS-induced chronic colitis perhaps by increasing the number of CD4(+)CD25(+) Tregs that suppress the secretion of proinflammatory cytokines and populations of Th1, Th17, and γδT cells.

Relationship of Treg/Th17 balance with HBeAg change in HBeAg-positive chronic hepatitis B patients receiving telbivudine antiviral treatment: A longitudinal observational study

Telbivudine (LdT) is an orally L-nucleoside with potent and specific antihepatitis B virus (HBV) activity. The higher rate of hepatitis B e antigen (HBeAg) seroconversion of LdT treatment than other anti-HBV agents suggests a potential immunomodulatory effect. The aim of the study was to investigate the changes of regulatory T cell (Treg)/interleukin (IL)-17-producing CD4+T helper (Th17) balance during LdT treatment and to discuss the relationship of Treg/Th17 balance with HBeAg change in HBeAg-positive chronic hepatitis B (CHB) patients receiving LdT antiviral treatment. Twenty-seven HBeAg-positive CHB patients received LdT for 24 weeks and the percentages of Tregs and cells (Th17 cells) in peripheral blood as well as the serum TGF-β1 and IL-17 levels in these patients were longitudinally analyzed. We found that the frequencies of Tregs and Th17 cells in peripheral blood as well as the serum TGF-β1 and IL-17 levels increased significantly in CHB patients compared with healthy controls. During the LdT treatment, the Tregs frequency and TGF-β1 level tended to decrease, and Th17 cells frequency and IL-17 level showed a reverse "V"-type change. The frequency of Tregs and the ratio of Treg/Th17 were significantly lower in the HBeAg loss group than those in the HBeAg no-loss group at the baseline. More important, the Tregs frequency and TGF-β1 level were both positively correlated with HBeAg level during the LdT treatment for 24 weeks. Our data suggest that the lower Tregs frequency and Treg/Th17 ratio at the baseline of LdT treatment, the more likely to get the HBeAg loss. HBeAg negative can be predicted using changes in Tregs frequency and TGF-β1 level during LdT treatment in CHB patients. Maybe we could provide the immunology marker for exploring the mechanism of the higher HBeAg seroconversion rate of LdT therapy.

Dendritic cells provide a therapeutic target for synthetic small molecule analogues of the parasitic worm product, ES-62

ES-62, a glycoprotein secreted by the parasitic filarial nematode Acanthocheilonema viteae, subverts host immune responses towards anti-inflammatory phenotypes by virtue of covalently attached phosphorylcholine (PC). The PC dictates that ES-62 exhibits protection in murine models of inflammatory disease and hence a library of drug-like PC-based small molecule analogues (SMAs) was synthesised. Four sulfone-containing SMAs termed 11a, 11e, 11i and 12b were found to reduce mouse bone marrow-derived dendritic cell (DC) pathogen-associated molecular pattern (PAMP)-induced pro-inflammatory cytokine production, inhibit NF-κB p65 activation, and suppress LPS-induced up-regulation of CD40 and CD86. Active SMAs also resulted in a DC phenotype that exhibited reduced capacity to prime antigen (Ag)-specific IFN-γ production during co-culture with naïve transgenic TCR DO.11.10 T cells in vitro and reduced their ability, following adoptive transfer, to prime the expansion of Ag-specific T lymphocytes, specifically TH17 cells, in vivo. Consistent with this, mice receiving DCs treated with SMAs exhibited significantly reduced severity of collagen-induced arthritis and this was accompanied by a significant reduction in IL-17+ cells in the draining lymph nodes. Collectively, these studies indicate that drug-like compounds that target DCs can be designed from parasitic worm products and demonstrate the potential for ES-62 SMA-based DC therapy in inflammatory disease.

Interleukin 17A Promotes Lymphocytes Adhesion and Induces CCL2 and CXCL1 Release from Brain Endothelial Cells

The nature of the interaction between Th17 cells and the blood-brain barrier (BBB) is critical for the development of autoimmune inflammation in the central nervous system (CNS). Tumor necrosis factor alpha (TNF-α) or interleukin 17 (IL-17) stimulation is known to enhance the adherence of Th17 cells to the brain endothelium. The brain endothelial cells (bEnd.3) express Vascular cell adhesion molecule 1 (VCAM-1), the receptor responsible for inflammatory cell adhesion, which binds very late antigen 4 (VLA-4) on migrating effector lymphocytes at the early stage of brain inflammation. The present study examines the effect of the pro-inflammatory cytokines TNF-α and IL-17 on the adherence of Th17 cells to bEnd.3. The bEnd.3 cells were found to increase production of CCL2 and CXCL1 after stimulation by pro-inflammatory cytokines, while CCL2, CCL5, CCL20 and IL17 induced Th17 cell migration through a bEnd.3 monolayer. This observation may suggest potential therapeutic targets for the prevention of autoimmune neuroinflammation development in the CNS.

Interleukin 17A Promotes Lymphocytes Adhesion and Induces CCL2 and CXCL1 Release from Brain Endothelial Cells

The nature of the interaction between Th17 cells and the blood-brain barrier (BBB) is critical for the development of autoimmune inflammation in the central nervous system (CNS). Tumor necrosis factor alpha (TNF-α) or interleukin 17 (IL-17) stimulation is known to enhance the adherence of Th17 cells to the brain endothelium. The brain endothelial cells (bEnd.3) express Vascular cell adhesion molecule 1 (VCAM-1), the receptor responsible for inflammatory cell adhesion, which binds very late antigen 4 (VLA-4) on migrating effector lymphocytes at the early stage of brain inflammation. The present study examines the effect of the pro-inflammatory cytokines TNF-α and IL-17 on the adherence of Th17 cells to bEnd.3. The bEnd.3 cells were found to increase production of CCL2 and CXCL1 after stimulation by pro-inflammatory cytokines, while CCL2, CCL5, CCL20 and IL17 induced Th17 cell migration through a bEnd.3 monolayer. This observation may suggest potential therapeutic targets for the prevention of autoimmune neuroinflammation development in the CNS.

Zaocys type II collagen regulates the balance of Treg/Th17 cells in mice with collagen-induced arthritis

OBJECTIVES

Zaocys type II collagen is an active collagen extracted from Zaocys that has been used to treat rheumatoid arthritis in China for over 1000 years. However, the mechanism still remains unknown. Therefore, we set out to investigate the inhibitory effect and possible mechanism of action of zaocys type II collagen on collagen-induced arthritis.

METHODS

Collagen-induced arthritis was induced in C57BL/6 mice by immunisation with type II collagen. After immunisation, the mice were treated with Zaocys type II collagen. Clinical and histological scores were assessed and the cytokine levels in the serum and lymphocytes supernatant from the spleen and mesenteric lymph node were determined by enzyme-linked immune sorbent assay. The T-helper 17 cell and regulatory-T cell frequencies were analysed by flow cytometry and the expression of interest markers was examined by direct immuno-fluorescence.

RESULTS

The arthritis score and severity of histological inflammation and cartilage destruction were dose-dependently reduced after treatment. The analysis results indicated that Zaocys type II collagen significantly increased the proportion of regulatory-T cells and lowered the T-helper 17 cells, it also increased the number of regulatory-T cells and conversely decreased the T-helper 17 cells in synovial tissue compared with the model group. Treatment also caused a higher level of transforming growth factor-β and a decreased production of interleukin -17A.

CONCLUSIONS

The oral administration of Zaocys type II collagen potently suppressed the severity of collagen-induced arthritis by repairing the imbalance between regulatory-T cells and T-helper 17 cells, suggesting that it might be a promising candidate for the treatment of rheumatoid arthritis.

1,25(OH)2D3 Protects Liver Fibrosis Through Decreasing the Generation of TH17 Cells

BACKGROUND The aim of this study was to study the effects of 1-alpha,25-dihydroxy-cholecalcifero (1,25(OH)2D3) on liver fibrosis and the generation of Th17 cells in vivo and in vitro. MATERIAL AND METHODS Thirty C57 mice were randomly divided into control, model, and treatment groups. Hepatic fibrosis was induced by subcutaneous injection of CCl4. Liver fibrosis condition was evaluated through pathological inspection and blood biochemical examination of liver function. Immunohistochemical assays were used to detect the expression of α-SMA, TGF-β, and collagen I to observe hepatic stellate cell activation level. Flow cytometry, ELISA, and RT-PCR were performed to explore the association between 1,25(OH)2D3 and Th17 cell differentiation. RESULTS Collagen I, TGF-β, and α-SMA were decreased after 1,25(OH)2D3 treatment. Consistently, RORγt mRNA and the rate of Th17 cells was significantly reduced after 1,25(OH)2D3 treatment. In vitro, the proportion of Th17 cells was also obviously reduced in the 1,25(OH)2D3 group, and mRNA levels of IL-17A, IL-22, RORγt, and RORa were significantly decrease in the 1,25(OH)2D3 group compared to the control group. CONCLUSIONS Treatment with 1,25(OH)2D3 can alleviate the damage caused by liver fibrosis. Experiments in vivo and in vitro showed that 1,25(OH)2D3 treatment deceased the rates of Th1 and Th17 cells and increased the rate of Th2 cells. The level of IL-17A, IL-22 and IFN-γ were decreased, while the level of IL-4 was increased by the treatment of 1,25(OH)2D3.

Cortistatin reduces atherosclerosis in hyperlipidemic ApoE-deficient mice and the formation of foam cells

Atherosclerosis is a chronic inflammatory cardiovascular disease that is responsible of high mortality worldwide. Evidence indicates that maladaptive autoimmune responses in the arterial wall play critical roles in the process of atherosclerosis. Cortistatin is a neuropeptide expressed in the vascular system and atherosclerotic plaques that regulates vascular calcification and neointimal formation, and inhibits inflammation in different experimental models of autoimmune diseases. Its role in inflammatory cardiovascular disorders is largely unexplored. The aim of this study is to investigate the potential therapeutic effects of cortistatin in two well-established preclinical models of atherosclerosis, and the molecular and cellular mechanisms involved. Systemic treatment with cortistatin reduced the number and size of atherosclerotic plaques in carotid artery, heart, aortic arch and aorta in acute and chronic atherosclerosis induced in apolipoprotein E-deficient mice fed a high-lipid diet. This effect was exerted at multiple levels. Cortistatin reduced Th1/Th17-driven inflammatory responses and increased regulatory T cells in atherosclerotic arteries and lymphoid organs. Moreover, cortistatin reduced the capacity of endothelial cells to bind and recruit immune cells to the plaque and impaired the formation of foam cells by enhancing cholesterol efflux from macrophages. Cortistatin emerges as a new candidate for the treatment of the clinical manifestations of atherosclerosis.

Nutritional control of IL-23/Th17-mediated autoimmune disease through HO-1/STAT3 activation

The nutritional curcumin (CUR) is beneficial in cell-mediated autoimmune diseases. The molecular mechanisms underlying this food-mediated silencing of inflammatory immune responses are poorly understood. By investigating antigen-specific immune responses we found that dietary CUR impairs the differentiation of Th1/Th17 cells in vivo during encephalomyelitis and instead promoted Th2 cells. In contrast, feeding CUR had no inhibitory effect on ovalbumin-induced airway inflammation. Mechanistically, we found that CUR induces an anti-inflammatory phenotype in dendritic cells (DC) with enhanced STAT3 phosphorylation and suppressed expression of Il12b and Il23a. On the molecular level CUR readily induced NRF2-sensitive heme oxygenase 1 (HO-1) mRNA and protein in LPS-activated DC. HO-1 enhanced STAT3 phosphorylation, which enriched to Il12b and Il23a loci and negatively regulated their transcription. These findings demonstrate the underlying mechanism through which a nutritional can interfere with the immune response. CUR silences IL-23/Th17-mediated pathology by enhancing HO-1/STAT3 interaction in DC.

Comparable therapeutic potential of umbilical cord mesenchymal stem cells in collagen-induced arthritis to TNF inhibitor or anti-CD20 treatment

OBJECTIVES

The effects of mesenchymal stem cell (MSC) transplantation on established collagen-induced arthritis (CIA) were evaluated and compared to biologic therapies.

METHODS

CIA was induced with the immunisation of type II collagen (CII) in DBA/1 mice. Human umbilical cord MSC, anti-TNF antibody, rhTNFR:Fc fusion protein and anti-CD20 antibody were respectively injected intraperitoneally into CIA mice. Arthritis severity was assessed by clinical and histological scoring. The frequencies of lymphocytes in spleen were analysed, and serum concentrations of cytokines and autoantibody to CII were also measured. The ability of MSC to regulate the balance of T helper cell subsets in CII stimulated CIA CD4+ T cells was assessed in vitro.

RESULTS

MSC treatment significantly decreased the severity of arthritis, which was comparable to biologic treatments. All the treatments down-regulated Th1 subset. Except anti-CD20 all the treatments decreased Th17 subset. MSC treatment enhanced the proportion of regulatory T (Treg) cells and inhibited the generation of T follicular helper (Tfh) cells. The decrease in autoantibody level was detectable in all the treated groups. In vitro MSC induced Foxp3+ T cells, and down-regulated IL-17+, IFNγ+ T cells and pathogenic IL-17+IFNγ+ or IL-17+Foxp3+ T cells. MSC also reduced the secretion of IL-1β, IL-6, IL-17 and TNF-α among collagen-specific T cells.

CONCLUSIONS

MSC show comparable effects to the known biologic treatments and correct immune imbalance in CIA. MSC might provide a promising approach for the treatment of rheumatoid arthritis.

Immunopathology alters Th17 cell glucocorticoid sensitivity

Th17 cells contribute to several inflammatory conditions and increasing evidence supports that Th17 cells are glucocorticoid resistant. However, Th17 cells in psoriasis and related diseases are glucocorticoid sensitive. We compare glucocorticoid sensitive and resistant immunological diseases and suggest that several aspects in Th17-related diseases alter glucocorticoid sensitivity of Th17 cells. We identify molecular pathways that are implicated in glucocorticoid sensitivity of Th17 cells in the literature, as this information is useful for developing approaches to overcome glucocorticoid-resistant immunopathology.

Isogarcinol Extracted from Garcinia mangostana L. Ameliorates Imiquimod-Induced Psoriasis-like Skin Lesions in Mice

Isogarcinol (YDIS), a natural compound extracted from Garcinia mangostana L., has a significant immunosuppressive effect on systemic lupus erythematosus and rheumatoid arthritis. This paper reports that it reduced imiquimod-induced psoriasis-like skin lesions in mice. It strongly attenuated the aberrant proliferation and differentiation of keratinocytes. Moreover, the expression of genes involving the interleukin-23 (IL-23)/T-helper 17 (Th17) axis was significantly inhibited in the dorsal skin of the YDIS-treated mice, as was that of the other pro-inflammatory factors TNF-α, IL-2, and even interferon (IFN)-γ. Furthermore, YDIS prevented the abnormal distribution of T cell types and suppressed the differentiation of CD4⁺ T cells into Th17 cells in the spleens of mice exposed to imiquimod. Interestingly, it elevated numbers of regulatory T cells (Tregs) in the spleen and boosted IL-10 expression in the skin. In agreement with the above, YDIS increased serum IL-10 and reduced serum IL-17. It also caused less damage to the liver and, especially, kidneys of mice than cyclosporine A (CsA). In vitro, YDIS caused more death of HaCaT keratinocytes than CsA. It also strongly inhibited inflammatory factor expression in lipopolysaccharide (LPS)-stimulated HaCaT cells. These findings suggest that YDIS is a promising immunosuppressive agent for treating psoriasis.

The immunomodulatory effects of TNF-α inhibitors on human Th17 cells via RORγt histone acetylation

The presence of interleukin (IL)-17-related cytokines correlates with rheumatoid arthritis (RA) pathogenesis. Epigenetic modifications, including histone acetylation, regulate gene expression in RA pathogenesis. Tumour necrosis factor-alpha (TNF-α) inhibitors such as etanercept and adalimumab, represent a breakthrough in RA treatment. We aimed to investigate the effects of etanercept and adalimumab on human Th17-polarized cells and the possible intracellular regulators of these effects, including the Th17-specific transcription factors signal transducer, activator of transcription 3 (STAT3), retinoid-related orphan receptor γ-T (RORγt) and epigenetic modification. Human CD4+ T cells from healthy subjects and patients with RA were pretreated with TNF-α inhibitors and then being polarized into IL-17-producing cells. The Th17-related cytokine levels in the culture supernatants were determined with an enzyme-linked immunosorbent assay. Intracellular signalling was investigated by western blot, real-time RT-PCR, and chromatin immunoprecipitation. Th17-polarized cells from patients with RA produced more IL-17A, IL-17F and IL-22 than those from healthy subjects. Etanercept and adalimumab suppressed IL-17A, IL-17F and IL-22 levels in Th17-polarized cells from healthy subjects and patients with RA. Western blot analysis revealed that etanercept and adalimumab decreased mitogen-activated protein kinase-phospho-p38, nuclear factor-κB-phospho-p65, phospho-STAT3 and RORγt levels. Etanercept and adalimumab decreased histone (H)3 and H4 acetylation in the RORγt gene promotor region by decreasing the recruitment of the acetyltransferases p300, CBP and PCAF. The present study broadens our knowledge of the mechanisms underlying the immunomodulatory effects of TNF-α inhibitors in rheumatoid arthritis treatment.

Therapeutic Potential of Targeting the Th17/Treg Axis in Autoimmune Disorders

A disruption of the crucial balance between regulatory T-cells (Tregs) and Th17-cells was recently implicated in various autoimmune disorders. Tregs are responsible for the maintenance of self-tolerance, thus inhibiting autoimmunity, whereas pro-inflammatory Th17-cells contribute to the induction and propagation of inflammation. Distortion of the Th17/Treg balance favoring the  pro-inflammatory Th17 side is hence suspected to contribute to exacerbation of autoimmune disorders. This review aims to summarize recent data and advances in targeted therapeutic modification of the Th17/Treg-balance, as well as information on the efficacy of candidate therapeutics with respect to the treatment of autoimmune diseases.

Effect of nucleoside analogues in the treatment of hepatitis B cirrhosis and its effect on Th17 cell

OBJECTIVE

We conducted this study to analyze the effects of nucleoside analogues in the treatment of hepatitis B cirrhosis and its effect on Th17 cells.

PATIENTS AND METHODS

120 patients were randomly divided into lamivudine combined with adefovir dipivoxil group (combined group) and entecavir group. There were 59 cases in the combined group and 59 cases in entecavir group. The combined group was administered lamivudine 100 mg/d + adefovir dipivoxil 10 mg/d and entecavir group was administered entecavir 0.5 mg/d. The treatment was continued until there was virus negativity and it maintains for at least 3 months.

RESULTS

The treatment effects were compared. We compared the average rate of viral clearance time and virus clearance of two groups of patients; the difference was not statistically significant (p>0.05). The relapse rate after a negative test of entecavir group was lower than that of the combined group (p<0.05). Before and after treatment, the levels of TBIL, ALT and ALB in the two groups were compared; the differences were not statistically significant (p>0.05). The Th17 cell proportion and the level of IL-17 after treatment of the entecavir group were lower than those before treatment. The combined group exhibited no change, and the entecavir group was lower than combined group; the differences were statistically significant (p<0.05).

CONCLUSIONS

Therefore, the effects of the combination of lamivudine and adefovir dipivoxil is the same as single entecavir treatment of hepatitis B cirrhosis suppression of viral replication. It does not increase liver injury and the antiviral effects of entecavir may be related to inhibition of the expression of Th17 cells and effector molecules IL-17.

[Therapeutic effect of adipose tissue-derived stem cells on bleomycin-induced mice of scleroderma]

OBJECTIVE

To investigate the effects and mechanisms of adipose-derived stem cells (ADSCs) on bleomycin-induced mice of scleroderma.

METHODS

In the study, 24 C57BL/6J female mice were randomly divided into control group, bleomycin(BLM)group, ADSCs (hypodermic injection) group and ADSCs (intravenous injection) group . BLM [2 mg/(kg×d)] was injected into the mice to establish the model of scleroderma. There were 6 mice in each group .The control group mice were injected with normal saline 2 mL/(kg×d) by subcutaneously. The rest of the three groups were injected with BLM. ADSCs groups were injected with ADSCs (2×10⁵) subcutaneously and intravenously, respectively. T-helper 17 (Th17) and regulatory T cell (Treg cell) of spleen cells were detected by flow cytometry. The levels of cytokines in the lung tissue and in the serum were detected by real-time fluorescence quantification. Real-time polymerase chain reaction(PCR) and enzyme-linked immuno sorbent assay(ELISA). The pathology change of skin and lung tissue was observed by hematoxylin eosin (HE) staining.

RESULTS

The proportion of Th17 and Treg increased in BLM group than in control group(15.30%±1.29% vs.4.32%±0.79%; 9.90%±1.95% vs.5.18%±1.35%, P<0.05), the expression of Th17 significantly decreased (5.02%±0.83%, 6.00%±0.82% vs.15.30%±1.29%, P<0.05) and the expression of Treg increased after the ADSCs therapy (14.32%±1.59%, 11.09%±4.31% vs. 9.90%±1.95%, P<0.05). The expression levels of IL-17,IL-6,tumor necrosis factor-α (TNF-α)mRNA in the lung tissue and IL-6 in the serum increased in BLM group than in control group [3.54±0.30, 10.65±0.66, 5.37±0.52 vs. 1.00±0.00; (21.2±1.74) ng/L vs. (16.87±1.09) ng/L, P<0.05]. The expression of these cytokines significant decreased after the ADSCs therapy [1.63±0.45,1.50±0.29 vs.3.54±0.30; 3.11±0.85, 2.98±0.76 vs.10.65±0.66;1.45±0.47, 1.59±0.41 vs. 5.37±0.52; (17.87±1.45) ng/L, (17.61±1.16) ng/L vs. (21.2±1.74) ng/L, P<0.05]. But there was no obvious difference between ADSCs (hypodermic injection) group and ADSCs (intravenous injection) group(P>0.05). The expression of TGF-β in the serum increased in BLM group than in control group[(33.95±2.49) ng/L vs. (28.8± 2.29) ng/L, P<0.05], however, the expression of TGF-β mRNA had no significant differences than that of control group (1.17±0.11 vs.1.00±0.00, P>0.05). The expression of TGF-β mRNA and protein had no significant differences than that of BLM group [1.25±0.11,1.26±0.12 vs.1.17±0.11; (31.84±2.04) ng/L, (31.25±2.36) ng/L vs. (33.95±2.49) ng/L, P>0.05]. HE staining showed that the inflammation of lung tissue was relieved and the dermal thickness and collagen deposition were decreased after the ADSCs therapy.

CONCLUSION

ADSCs could effectively alleviate inflammation of the lungs and fibrosis of skin; the effects of anti-inflammatory and anti-fibrosis were associated with immune regulating function.

A betulinic acid derivative SH479 inhibits collagen-induced arthritis by modulating T cell differentiation and cytokine balance

The ideal therapeutic drug for rheumatoid arthritis (RA) should not only inhibit inflammation, but also prevent articular joint damage and particularly inhibit osteoclastogenesis. Betulinic acid (BA) is a natural pentacyclic triterpene that has displayed moderate anti-inflammatory and anti-osteoclastogenesis activities in various experimental systems, suggesting that BA or its derivatives could have an inhibitory effect on RA. In this study, we screened BA derivatives and found a heterocyclic ring-fused BA derivative, SH479, which had greater inhibitory effect than BA on Th17 differentiation. Moreover, we investigated the immune regulatory activity and potential therapeutic effects of SH479 in an experimental model of rheumatoid arthritis, the collagen-induced arthritis (CIA) mouse model. SH479 significantly inhibited Th1 and Th17 polarization, antigen-specific T cell proliferation and splenic lymphocyte-induced osteoclastogenesis. Furthermore, it diminished arthritis scores as well as bone destruction and cartilage depletion in the CIA mouse model. The protective effect of SH479 was accompanied by decreased levels of pro-inflammatory cytokines IL-17 and IFN-γ, together with enhanced anti-inflammatory cytokine expression including IL-10 and IL-4, as well as elevated CD4⁺ Foxp3⁺ cell number. At the molecular level, our results indicated that SH479 alleviated CIA through regulation of CD4⁺ T cell subtypes by JAK-STAT pathways. In conclusion, this study demonstrates that SH479 has therapeutic potential for rheumatoid arthritis through an anti-inflammatory effect by shifting a pathogenic Th17/Th1 response to a Th2/Treg phenotype, and also through an additional articular bone protection effect.

Pharmacologic modulation of RORγt translates to efficacy in preclinical and translational models of psoriasis and inflammatory arthritis

The IL-23/IL-17 pathway is implicated in autoimmune diseases, particularly psoriasis, where biologics targeting IL-23 and IL-17 have shown significant clinical efficacy. Retinoid-related orphan nuclear receptor gamma t (RORγt) is required for Th17 differentiation and IL-17 production in adaptive and innate immune cells. We identified JNJ-54271074, a potent and highly-selective RORγt inverse agonist, which dose-dependently inhibited RORγt-driven transcription, decreased co-activator binding and promoted interaction with co-repressor protein. This compound selectively blocked Th17 differentiation, significantly reduced IL-17A production from memory T cells, and decreased IL-17A- and IL-22-producing human and murine γδ and NKT cells. In a murine collagen-induced arthritis model, JNJ-54271074 dose-dependently suppressed joint inflammation. Furthermore, JNJ-54271074 suppressed IL-17A production in human PBMC from rheumatoid arthritis patients. RORγt-deficient mice showed decreased IL-23-induced psoriasis-like skin inflammation and cytokine gene expression, consistent with dose-dependent inhibition in wild-type mice through oral dosing of JNJ-54271074. In a translational model of human psoriatic epidermal cells and skin-homing T cells, JNJ-54271074 selectively inhibited streptococcus extract-induced IL-17A and IL-17F. JNJ-54271074 is thus a potent, selective RORγt modulator with therapeutic potential in IL-23/IL-17 mediated autoimmune diseases.

Docosahexaenoyl serotonin, an endogenously formed n-3 fatty acid-serotonin conjugate has anti-inflammatory properties by attenuating IL-23-IL-17 signaling in macrophages

Conjugates of fatty acids and amines, including endocannabinoids, are known to play important roles as endogenous signaling molecules. Among these, the ethanolamine conjugate of the n-3 poly unsaturated long chain fatty acid (PUFA) docosahexaenoic acid (22:6n-3) (DHA) was shown to possess strong anti-inflammatory properties. Previously, we identified the serotonin conjugate of DHA, docosahexaenoyl serotonin (DHA-5-HT), in intestinal tissues and showed that its levels are markedly influenced by intake of n-3 PUFAs. However, its biological roles remain to be elucidated. Here, we show that DHA-5-HT possesses potent anti-inflammatory properties by attenuating the IL-23-IL-17 signaling cascade in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Transcriptome analysis revealed that DHA-5-HT down-regulates LPS-induced genes, particularly those involved in generating a CD4+ Th17 response. Hence, levels of PGE2, IL-6, IL-1β, and IL-23, all pivotal macrophage-produced mediators driving the activation of pathogenic Th17 cells in a concerted way, were found to be significantly suppressed by concentrations as low as 100-500nM DHA-5-HT. Furthermore, DHA-5-HT inhibited the ability of RAW264.7 cells to migrate and downregulated chemokines like MCP-1, CCL-20, and gene-expression of CCL-22 and of several metalloproteinases. Gene set enrichment analysis (GSEA) suggested negative overlap with gene sets linked to inflammatory bowel disease (IBD) and positive overlap with gene sets related to the Nrf2 pathway. The specific formation of DHA-5-HT in the gut, combined with increasing data underlining the importance of the IL-23-IL-17 signaling pathway in the etiology of many chronic inflammatory diseases merits further investigation into its potential as therapeutic compound in e.g. IBD or intestinal tumorigenesis.