Regulatory effect of daphnetin, a coumarin extracted from Daphne odora, on the balance of Treg and Th17 in collagen-induced arthritis

Daphnetin extracted from Daphne odora Var. marginata contains coumarin compounds, which possess properties of analgesic and anti-inflammatory effects. In this study, we investigated the therapeutic effect of daphnetin on anti-arthritis and its role on the balance of Tregs and Th17, using a collagen-induced arthritis rat model. Collagen-induced arthritis rats were treated with daphnetin for 21 days. The therapeutic effects of daphnetin were evaluated by clinical symptoms and histopathology. The levels of Th17-, Treg-, Th2-, Th1-type cytokines in serum were determined by ELISA. The expression levels of related receptors RORγt, NF-κB, Foxp3 and CD77 in joint tissues were detected by immunohistochemistry. Our results showed that administration of daphnetin significantly alleviated the severity of the arthritis, as evidenced by the reduction of arthritis scores, suppression of the infiltration of inflammatory cells and prevention of synovial hyperplasia, thereby resulting in the joint destruction in the arthritis rats. Additionally, daphnetin treatment reduced the serum level of Th17-, Th2- and Th1-type in collagen-induced arthritis rats. Correspondingly, the expression of RORγt, NF-κB and CD77 in joint tissue of collagen-induced arthritis rats was remarkably decreased, while the expression of Foxp3 and IL-10 was remarkably increased after being administered with daphnetin. Collectively, this study demonstrated that administration of daphnetin attenuated the clinical symptoms and pathological destruction of arthritis joints. The therapeutic effects were associated with the up-regulation of Tregs, down-regulation of Th17-, Th2- and Th1-type cell responses. The results provide novel evidence that daphnetin has therapeutic effects on autoimmune arthritis through modulating the balance of Tregs and Th17.     

Alantolactone alleviates collagen-induced arthritis and inhibits Th17 cell differentiation through modulation of STAT3 signalling

Context Alantolactone, the bioactive component in Inula helenium L. (Asteraceae), exhibits multiple biological effects.Objective We aimed to determine the anti-inflammatory effect of alantolactone in a collagen-induced arthritis (CIA) mouse model and its immunomodulatory effects on Th17 differentiation.Materials and methods A CIA mouse model was established with DBA/1 mice randomly divided into four groups (n = 6): healthy, vehicle and two alantolactone-treated groups (25 or 50 mg/kg), followed by oral administration of alantolactone to mice for 21 consecutive days after arthritis onset. The severity of CIA was evaluated by an arthritic scoring system and histopathological examination. Levels of cytokines and anti-CII antibodies as well as percentages of splenic Th17 and Th17 differentiation with or without alantolactone treatments (0.62, 1.2 or 2.5 μM) were detected with ELISA and flow cytometry, respectively. Western blot analysis was used to evaluate intracellular signalling in alantolactone-treated spleen cells.Results In CIA mice, alantolactone at 50 mg/kg attenuated RA symptoms, including high arthritis scores, infiltrating inflammatory cells, synovial hyperplasia, bone erosion and levels of the proinflammatory cytokines TNF-α, IL-6 and IL-17A, but not IL-10 in paw tissues. Alantolactone also reduced the number of splenic Th17 cells and the capability of naïve CD4⁺ T cells to differentiate into the Th17 subset by downregulating STAT3/RORγt signalling by as early as 24 h of treatment.Discussion and conclusions Alantolactone possesses an anti-inflammatory effect that suppresses murine CIA by inhibiting Th17 cell differentiation, suggesting alantolactone is an adjunctive therapeutic candidate to treat rheumatoid arthritis.     

Crocin exerts anti-inflammatory and anti-arthritic effects on type II collagen-induced arthritis in rats

Context: Rheumatoid arthritis (RA) is a common systemic auto-immune disease, which is characterized by chronic and symmetry synovial inflammation. Crocin has been reported to exhibit anti-inflammatory effects in animal models.

Objective: This study investigates the anti-inflammatory and anti-arthritic effects of crocin on type II collagen-induced arthritis (CIA) in Wistar rats.

Materials and methods: The CIA rat model was established and randomly divided into five groups with or without crocin treatment (10, 20 or 40?mg/kg), which was started on day 21 after arthritis induction and persisted for 36 days. The symptoms and molecular mechanisms of CIA and crocin-treated CIA rats were compared and investigated.

Results: CIA rats presented severe RA symptoms, including high arthritis score, paw swelling, joint inflammation, bone erosion, chondrocyte death, cartilage destruction, enhanced expressions of matrix metalloproteinase (MMP) and pro-inflammatory cytokines. However, crocin could mitigate these symptoms. Crocin (40?mg/kg) exhibited the most efficient therapeutic function on CIA rats: the histological scores of joint inflammation, bone erosion, chondrocyte death, cartilage surface erosion, and bone erosion of CIA rats receiving 40?mg/kg crocin treatment were comparable to the normal rats. MMP-1, -3 and -13 protein expression levels of CIA rats with 40?mg/kg crocin treatment were decreased to levels similar to normal rats. Moreover, crocin could also inhibit the expression of TNF-α, IL-17, IL-6 and CXCL8 in serum and ankle tissues of CIA rats.

Conclusions: In summary, crocin exhibits therapeutic potential for RA, by mitigating the symptoms and inhibiting the pro-inflammatory factor expression.     

Naltrexone (NTX) relieves inflammation in the collagen-induced- arthritis (CIA) rat models through regulating TLR4/NFκB signaling pathway

ObjectiveOur aim was to study the efficacy and mechanism by which NTX alleviate arthritis in CIA rat models in vivo.MethodsFemale Wistar rats were randomly divided into 6 groups, their weights were observed and the severity of arthritis and pathological changes were evaluated by HE staining. T lymphocyte subsets were detected by flow cytometry. The expression of cytokines was detected in peripheral serum by ELISA. Real time PCR, immunohistochemical staining and western blot analysis were utilized to detect the mRNA and protein expression of opioid receptors, TLR4, RANKL and /NF-κB in synovial tissue and the spleen.ResultsThe weight of the rats in the 10 mg/kg NTX group decreased the least, and had the least severe arthritis. CD4⁺ T cells, Th1 cells and Treg cells increased, and CD8⁺T cells, Th1 cells and Th17 cells decreased in the splenic lymphocytes. The expression of proinflammatory cytokines decreased, and the expression of anti-inflammatory cytokines increased. MOR and DOR were strongly expressed in the spleen, whereas KOR and DOR were strongly expressed in synovial tissue. The expression of TLR4, NF-κB and RANKL was reduced in the spleen and synovium in the NTX group.ConclusionsNTX relieved the severity of arthritis in the CIA rat models at a concentration of 10 mg/kg by regulating T lymphocyte subsets and the expression of cytokines. NTX affected opioid receptors to inhibit the TLR4/NF-κB signaling pathway, regulating the systemic immune response and decreasing osteoclast differentiation, thereby alleviating inflammation and the erosion of articular cartilage along with bone tissue.     

Periplocoside A ameliorated type II collagen-induced arthritis in mice via regulation of the balance of Th17/Treg cells

Periplocoside A (PSA) has been extracted from the Chinese herbal medicine Periploca sepium Bge to treat rheumatoid arthritis (RA) via immune regulation. We previously found that PSA exhibits immunosuppressive activity both in vitro and in vivo. Balanced regulation of helper T 17 (Th17)/regulatory T (Treg) cells is the current therapeutic direction for the treatment of RA. The present study investigated the mechanism of PSA in treating collagen-induced arthritis (CIA). The therapeutic effects and potential pharmacological mechanisms of PSA were specifically clarified by examining its effects on CIA in DBA/1 mice. PSA administration significantly relieved the severity of the arthritis, and preventive administration of PSA reduced the incidence of arthritis in the mice with CIA and relieved joint damage in terms of morphology. PSA was also able to reduce the levels of anti-collagen II (CII) antibodies and pro-inflammatory cytokines in the serum. As a result, the proportion of Th17 cells decreased, and the proportion of Treg cells increased. A follow-up study of the ex vivo immunological reactions induced by a specific antigen found that PSA suppressed lymphocyte proliferation, inhibited the differentiation and reactivity of Th17 cells, and promoted the proportion of Treg cells among helper T cells. PSA also exhibited pharmacological effect in regulating the balance between Th17 and Treg cells in CIA through relevant signalling pathways. Thus, PSA played a specific role in CIA treatment. In particular, our results suggest that the therapeutic effects of PSA on RA are partially realized via the regulation of the balance of Th17/Treg cells.     

The Efficacy and Mechanism Action of RvCSd,a New Herbal Agent,on Immune Suppression and Cartilage Protection in a Mouse Model of Rheumatoid Arthritis

The aim of the present study is to investigate the potential therapeutic action of RvCSd, an oriental herbal mixture, in an experimental model of rheumatoid arthritis (RA). DBA/1J mice were immunized with type II collagen. After a second collagen immunization, mice were treated with RvCSd or methotrexate (MTX) orally once a day for 35 days, and the incidence, clinical score, and joint histopathology were evaluated. The inflammatory response cytokines and cartilage protection effect were determined by measuring the levels in the joints and sera. The Th1/Th2-mediated auto-reactive response was evaluated by determining the proliferative response and cytokines of drained spleen cells stimulated with type II collagen. RvCSd treatment significantly reduced the incidence and severity of CIA, markedly abrogating joint swelling, synovial hyperplasia, and cartilage destruction. RvCSd significantly inhibited the production of interleukin (IL)-1β, tumor necrosis factor (TNF)-α and IL-6, IL-2, interferon (IFN)-γ, and matrix metalloproteinases (MMP)-1 and up-regulated anti-inflammatory cytokines IL-4, IL-10, and metalloproteinase (TIMP)-1 in mice with CIA. In conclusion, RvCSd has therapeutic effects exerted through inhibition of inflammatory and Th1 responses, regulation of MMP/TIMP, and induction of regulatory T cells in CIA; these effects make RvCSd an outstanding candidate for use as an immune suppressive and cartilage protective medicine in RA patients.     

A combination of Sinomenine and Methotrexate reduces joint damage of collagen induced arthritis in rats by modulating osteoclast-related cytokines

ObjectiveTo analyze the combination therapy of Sinomenine (SIN) and Methotrexate (MTX) in rheumatoid arthritis (RA), we herein demonstrated the combination effect of SIN and MTX on collagen-induced arthritis (CIA) in rats through their modulation on osteoclast-related cytokines.MethodsCIA was induced by the immunization of type II collagen (CII) in SD rats. SIN and MTX were administrated alone or in combination after the onset of arthritis. Arthritis index and histological analysis were used to evaluate the effect of treatments. Effects of SIN and MTX on expression of receptor activator of NF-κB ligand (RANKL) and osteopontin (OPN) in synovial tissues were assayed by immunohistochemistry. RANKL, osteoprotegerin (OPG), IL-6, IL-17 and matrix metalloproteinases (MMPs) in rat serum were measured by ELISA. The expression of osteoclast-related cytokines in fibroblast-like synoviocytes (FLS) from RA patients was assayed by RT-PCR.ResultsSIN and MTX combination additively reduced the inflammatory symptoms and joint damage in CIA. Combination of SIN and MTX significantly repressed synovial RANKL and OPN production. SIN and MTX exhibited complementary and synergistic effect upon down-regulating RANKL, IL-6, IL-17 and MMPs in rat serum. SIN and MTX also modulated the expression of RANKL and OPG in RA-FLS.ConclusionSIN and MTX have additive effects, decreasing inflammation and joint damage in CIA rats by modulating osteoclast-related cytokines. These results are indicative of the combined effect of SIN and MTX for anti-arthritic treatment in RA.     

Ethyl pyruvate ameliorates inflammatory arthritis in mice

ObjectivesEthyl pyruvate (EP) is the ethyl ester of pyruvate and has antioxidative and anti-inflammatory effects. This study aimed to evaluate the therapeutic effect of EP in inflammatory arthritis and to identify the underlying mechanisms.MethodsMice with collagen-induced arthritis (CIA) were treated with the vehicle control or EP at 20 mg/kg, and clinical and histological analyses were performed on the animals. The differentiation of murine CD4 + T cells into T helper 17 (Th17) cells in the presence of EP was investigated in vitro. The effects of EP on osteoclastogenesis were determined by staining for tartrate-resistant acid phosphatase, and measuring the mRNA levels of osteoclastogenesis-related genes. The expression of high-mobility group box 1 (HMGB1) was evaluated after EP therapy using immunohistochemical staining and Western blotting.ResultsEP significantly improved the clinical and histological features of arthritis in CIA mice. EP suppressed the differentiation of CD4 + T cells into Th17 cells, and inhibited the expression of RORγt. The generation of osteoclasts and osteoclastogenic markers from murine and human monocytes was significantly reduced in the presence of EP. The expression of HMGB1 in the synovium was significantly lower in CIA mice treated with EP, compared to control CIA mice. During osteoclastogenesis, HMGB1 release from monocytes was inhibited in the presence of EP.ConclusionsEP attenuated synovial inflammation and bone destruction in the experimental arthritis model through suppression of IL-17 and HMGB-1. The data suggests that EP could be a novel therapeutic agent for the treatment of inflammatory arthritis, such as rheumatoid arthritis.     

CP-25 alleviates rat collagen induced arthritis by regulating T cell subsets

Rheumatoid arthritis(RA) is a chronic,systemic and autoimmune disease. Abnormally activated T cells play a key role in the pathological mechanism of RA, and the differentiated T cell subsets also have imbalance in RA. Paeoniflorin-6-oxygen-benzenesulfonate(code CP-25) is a new active monomer derived from paeoniflorin. OBJECTIVE To investigate the therapeutic effect of CP-25 on collagen induced-arthritis(CIA) rats and regulation on T cell subsets. METHODS Rats with CIA were establisghed and administered with CP-25(50 mg·kg~(-1)) in tragastric administration, and Iguratimod(25 mg·kg~(-1)) was given as positive control drug. The therapeutic effects of CP-25 on the CIA of rats and its regulatory effects on the T cell subsets were evaluated by measuring the foot paw volume, the number of swollen joints,the histopathology of the joints and spleen and the T cell subgroup. The proliferation of T and B cells, cytokines and T lymphocyte subsets were analyzed by CCK-8, ELISA and flow cytometry. RESULTS CP-25 has therapeutic effect on CIA in rats. CP-25(50 mg·kg~(-1)) can significantly reduce the paw volume and joint swelling of CIA rats,reduce the white myelosis of spleen and synovial tissue inflammatory cell infiltration, inhibit the proliferation of T cells. The ratio of CD3~+T cells, CD3~+CD4~+T cells, CD3~+CD4~+CD25~+T cell subsets, Th1, Th2 and Th17 cells increased significantly in CIA rats. CP-25 reduce CD3~+T cels, CD3~+CD4~+T cels, CD3~+CD4~+CD25~+T cel subgroups,downregulate the ratio of Th1, Th2 and Th17 cells, and the above indicators were not statistically significant with the positive control group. CONCLUSION CP-25 has antiinflammatory effects on rats with CIA, which may be related to regulating activated T cell subsets and the differentiation of T cell subsets.     

地塞米松改善胶原性关节炎大鼠免疫功能与其血药浓度的相关性研究

目的 研究地塞米松对胶原诱导性关节炎(Collagen induced arthritis,CIA)大鼠炎症和免疫的调节作用.方法 32只Wistar大鼠,分为3组,正常组10只、模型组11只,给药组11只.建立CIA模型后,给药组腹腔注射地塞米松(1 mg/kg),每周3次.连续给药4周后,处死并计算脾脏指数、胸腺指...     

Ursolic acid ameliorates autoimmune arthritis via suppression of Th17 and B cell differentiation

Aim:

Ursolic acid (UA) is a pentacyclic triterpenoid found in most plant species, which has been shown anti-inflammatory and anti-oxidative activities. In this study, we examined the effects of UA on collagen-induced arthritis (CIA) in mice, and to identify the mechanisms underlying the effects.

Methods:

CIA was induced in mice. Two weeks later, the mice were treated with UA (150 mg/kg, ip, 3 times per week) for 4 weeks. The expression of cytokines and oxidative stress markers in joint tissues was measured with immunohistochemistry. The numbers of CD4⁺IL-17⁺, CD4⁺CD25⁺Foxp3⁺ and pSTAT3 cells in spleens were determined using confocal immunostaining or flowcytometric analyses. Serum antibody levels and B cell-associated marker mRNAs were analyzed with ELISAs and qRT-PCR, respectively. CD4⁺ T cells and CD19⁺ B cells were purified from mice spleens for in vitro studies.

Results:

UA treatment significantly reduced the incidence and severity of CIA-induced arthritis, accompanied by decreased expression of proinflammatory cytokines (TNF-α, IL-1β, IL-6, IL-21 and IL-17) and oxidative stress markers (nitrotyrosine and iNOS) in arthritic joints. In CIA mice, UA treatment significantly decreased the number of Th17 cells, while increased the number of Treg cells in the spleens, which was consistent with decreased expression of pSTAT3, along with IL-17 and RORγt in the splenocytes. In addition, UA treatment significantly reduced the serum CII-specific IgG levels in CIA mice. The inhibitory effects of UA on Th17 cells were confirmed in an in vitro model of Th17 differentiation. Furthermore, UA dose-dependently suppressed the expression of B cell-associated markers Bcl-6, Blimp1 and AID mRNAs in purified CD19⁺ B cells pretreated with IL-21 or LPS in vitro.

Conclusion:

UA treatment significantly ameliorates CIA in mice via suppression of Th17 and differentiation. By targeting pathogenic Th17 cells and autoantibody production, UA may be useful for the treatment of autoimmune arthritis and other Th17-related diseases.     

来氟米特对胶原性关节炎大鼠T细胞漂移的影响

目的 探讨来氟米特对胶原性关节炎大鼠中Th1和Th2细胞漂移的影响.方法 建立胶原性关节炎模型;来氟米特2mg/kg灌胃给药;HE染色行膝关节滑膜病理学检查并评分;称重大鼠体重和脾脏重量,计算脾脏指数;RT-PCR法检测脾淋巴细胞中T-bet mRNA和GATA-3 mRNA的表达.ELISA法检测Con A刺激的脾淋巴细胞分泌Th1和Th2型细胞因子IFN-γ和IL-4的量.结果 与模型组比较,来氟米特(2mg/kg,灌胃给药15天)明显降低CIA大鼠病理组织学评分,降低脾脏指数.与关节炎模型组比较,药物干预组GATA-3 mRNA的表达增高、IL-4的分泌增多,T-bet mRNA的表达降低、IFN-γ的分泌减少.结论 来氟米特对胶原性关节炎具有治疗作用,该作用可能和维持T细胞亚群的平衡有关.     

Betahistine attenuates murine collagen-induced arthritis by suppressing both inflammatory and Th17 cell responses

The objective of this study was to evaluate the potential therapeutic effects of betahistine dihydrochloride (betahistine) in a collagen-induced arthritis (CIA) mouse model. CIA was induced in DBA/1 male mice by primary immunization with 100 μl of emulsion containing 2 mg/ml chicken type II collagen (CII) mixed with complete Freund's adjuvant (CFA) in an 1:1 ratio, and booster immunization with 100 μl of emulsion containing 2 mg/ml CII mixed with incomplete Freund's adjuvant (IFA) in an 1:1 ratio. Immunization was performed subcutaneously at the base of the tail. After being boosted on day 21, betahistine (1 and 5 mg/kg) was orally administered daily for 2 weeks. The severity of CIA was determined by arthritic scores and assessment of histopathological joint destruction. Expression of cytokines in the paw and anti-CII antibodies in the serum was evaluated by ELISA. The proliferative response against CII in the lymph node cells was measured by ³H-thymidine incorporation assay. The frequencies of different CII specific CD4⁺ T cell subsets in the lymph node were determined by flow-cytometric analysis. Betahistine treatment attenuated the severity of arthritis and reduced the levels of pro-inflammatory cytokines, including TNF-α, IL-6, IL-23 and IL-17A, in the paw tissues of CIA mice. Lymph node cells from betahistine-treated mice showed a decrease in proliferation, as well as a lower frequency of Th17 cells. In vitro, betahistine suppressed CD4⁺ T cell differentiation into Th17 cells. These results indicate that betahistine is effective in suppressing both inflammatory and Th17 responses in mouse CIA and that it may have therapeutic value as an adjunct treatment for rheumatoid arthritis.     

Chronotherapy targeting cytokine secretion attenuates collagen-induced arthritis in mice

ObjectiveDiurnal variation of symptoms are observed in rheumatoid arthritis, especially in productions of cytokines that show peak concentrations during mid night. In contrast, cytokines of collagen-induced arthritis (CIA) mice increase in daytimes under Mid-light condition. By using chronotherapy, differences in drug efficacies according to administration time of Baricitinib, a wide ranged cytokine blocker, were examined in CIA mice.MethodsCIA mice were administered a dose of 3 mg/kg of Baricitinib once a day at zeitgeber time (ZT) 0 or ZT12 for 21 days. Arthritis scores, histopathology and factors related to joint destruction in sera were examined. Phosphorylation of STAT3 in liver, expressions of cytokines in spleen, and Interleukin (IL)-6 and tumor necrosis factor (TNF)-α in sera were measured.ResultsIn CIA mice, diurnal variations were observed both in expressions of cytokines and phosphorylation of STAT3. Arthritis scores of ZT0/12 group decreased from day3 as compared to untreated mice, and those of ZT0 group significantly decreased as compared to ZT12 group from day12. Pathological findings, immunohistochemistry of cytokines and Receptor activator of nuclear factor kappa-Β ligand (RANKL)/osteoprotegerin ratio in sera well reflected results of arthritis scores. Diurnal variation of STAT3 phosphorylation was suppressed in ZT0 group. At ZT2, expressions of IL-6/Interferon-γ/TNF/granulocyte–macrophage colony-stimulating factor in ZT0 group were significantly decreased as compared to untreated mice, though not in ZT12 group. In ZT0 group, IL-6 and TNF-α in sera were decreased for longer time than that in ZT12 group.ConclusionChronotherapy using Baricitinib targeting cytokine secretions is effective in CIA mice. Clinical applications of chronotherapy can be expected to enhance the drug efficacy.     

胶原诱导性关节炎大鼠Th17细胞相关因子表达的研究

目的观察胶原诱导性关节炎(CIA)大鼠外周血中T辅助细胞17(Th17)相关细胞因子白细胞介素(IL)-6,IL-17和IL-23水平的变化。方法取40只Wistar雄性大鼠,随机分为正常对照组、CIA模型组,利用牛Ⅱ型胶原建立CIA大鼠模型,造模成功后观察CIA大鼠的关节肿胀程度,免疫后第48天处死大鼠,抽取静脉血,取血清,同时留取大鼠的肿胀的关节,留取滑膜组织。采用酶联免疫吸附试验(ELISA)观察各组对血清中细胞因子IL-6,IL-17和IL-23水平。结果 CIA鼠与正常对照组比较关节肿胀度明显升高。CIA大鼠外周血血清IL-6,IL-17和IL-23水平明显高于正常对照组。2组比较差异均有统计学(P<0.05)。结论 Th17相关细胞因子IL-6,IL-17和IL-23在CIA鼠的外周血中过度表达,提示Th17型细胞因子在RA的免疫致病机制中可能起重要作用。     

Butyrate inhibit collagen-induced arthritis via Treg/IL-10/Th17 axis

Rheumatoid arthritis (RA) is a chronic autoimmune disorder demanding the development of novel therapeutic strategy. Butyrate is a functional short-chain fatty acid produced by the anaerobic intestinal microbiota. This study aimed to investigate the attenuation of butyrate on RA. The collagen-induced arthritis (CIA) mouse model was established and butyrate was administered in drinking water along with the collagen immunization. The histopathological features, clinical score, paw swelling, as well as the production of pro-inflammatory cytokines including interleukin (IL)-1β, IL-6 and IL-17A were measured to determine the amelioration of butyrate on arthritis. The differentiation of Treg cells and Th17 cells in the splenic cells was assessed by flow cytometry. The expression of Foxp3, IL-10, Rorγt and IL-17A were detected by RT-PCR and FACS immunostaining. Anti-IL10R antibody was used in the CIA and CD4⁺ cell cultures to mediate the effects of butyrate. Butyrate significantly inhibited expressions of IL-1β, IL-6 and IL-17A, but promoted the expression of IL-10. Butyrate also increased systematical Treg cells and reduced Th17 cells. Mechanism study revealed that butyrate directly enhanced the polarization of Treg cells but not Th17 cells. All effects of butyrate on RA were inversed by the co-administered anti-IL10R antibody. This study showed that butyrate administration inhibited arthritis in CIA mice model, suppressed the expression of inflammatory cytokines. The modulation may be mediated the differentiation of CD4 T cells towards Treg cells, which produce anti-inflammatory cytokine IL-10, and thus influenced the function of Th17 cells.     

A novel antagonist of the prostaglandin E2 EP4 receptor inhibits Th1 differentiation and Th17 expansion and is orally active in arthritis models

Background and purpose:

Rheumatoid arthritis (RA) is an autoimmune disorder involving subsets of activated T cells, in particular T helper (Th) 1 and Th17 cells, which infiltrate and damage tissues and induce inflammation. Prostaglandin E₂ (PGE₂) enhances the Th17 response, exacerbates collagen-induced arthritis (CIA) and promotes inflammatory pain. The current study investigated whether selective antagonism of the PGE₂ EP₄ receptor would suppress Th1/Th17 cell development and inflammatory arthritis in animal models of RA.

Experimental approach:

Effects of PGE₂ and a novel EP₄ receptor antagonist ER-819762 on Th1 differentiation, interleukin-23 (IL-23) production by dendritic cells (DCs), and Th17 development were assessed in vitro. The effect of ER-819762 was evaluated in CIA and glucose-6-phosphate isomerase (GPI)-induced arthritis models. In addition, the effects of ER-819762 on pain were evaluated in a model of chronic inflammatory pain induced by complete Freund''s adjuvant (CFA) in the rat.

Key results:

Stimulation of the EP₄ receptor enhanced Th1 differentiation via phosphatidylinositol 3 kinase signalling, selectively promoted Th17 cell expansion, and induced IL-23 secretion by activated DCs, effects suppressed by ER-819762 or anti-PGE₂ antibody. Oral administration of ER-19762 suppressed Th1 and Th17 cytokine production, suppressed disease in collagen- and GPI-induced arthritis in mice, and suppressed CFA-induced inflammatory pain in rats.

Conclusion and implications:

PGE₂ stimulates EP₄ receptors to promote Th1 differentiation and Th17 expansion and is critically involved in development of arthritis in two animal models. Selective suppression of EP₄ receptor signalling may have therapeutic value in RA both by modifying inflammatory arthritis and by relieving pain.     

Partial depletion of natural gut flora by antibiotic aggravates collagen induced arthritis (CIA) in mice

BackgroundRheumatoid arthritis (RA) is a chronic inflammatory disease that affects about 1% of the adult population and occurs twice as frequently among women than men. At present it is accepted that pathogenesis of RA is based on inflammatory response mediated by CD4⁺ Th1 and Th17 lymphocytes. The most commonly applied model imitating RA is the collagen induced arthritis (CIA).A growing evidence shows that there is a correlation between microbial dysbiosis and human pathology which includes autoimmunity, allergic diseases, obesity, inflammatory bowel disease (IBD), metabolic syndrome.MethodsCollagen induced arthritis was used to study influence of natural gut flora on course of rheumatoid arthritis.ResultsCurrent work employing CIA model showed that partial depletion of natural gut flora with orally administered antibiotic Baytril (enrofloxacin) aggravates disease severity when compared to control mice. Observed partial depletion of both aerobic and anaerobic bacteria did not affect animal body weight. Additionally, in vitro study showed increased production of IFN-γ and IL-17A and decreased release of IL-4 by axillary lymph node cells (ALNC) isolated from mice treated with antibiotic and induced CIA when compared to positive control. Furthermore, treatment with antibiotic prior to CIA induction results in augmented production of IFN-γ, IL-17A and IL-6 by mesenteric lymph node cells (MLNC).ConclusionPresented data suggest that alteration of gut microbiota via use of enrofloxacin may play a role in modulating arthritis symptom severity in this mouse model.     

基于MAPK通路探讨蒿藤胶囊对Ⅱ型胶原诱导性关节炎大鼠的免疫抑制机制

目的：探讨蒿藤胶囊对Ⅱ型胶原诱导性关节炎模型（CIA）大鼠的免疫抑制机制。方法：采用弗氏完全佐剂与Ⅱ型胶原混合后乳剂诱导大鼠关节炎模型,每周检测大鼠右后足关节肿胀百分率;末次给药后,观察关节滑膜的病理变化,采用流式细胞术检测蒿藤胶囊对外周血中CD4⁺ T淋巴细胞的影响,酶联法检测蒿藤胶囊对血清中TNF-α、IL-17、IL-6、IL-21及IL-22的影响,PCR法测定蒿藤胶囊对脾脏组织中JNK、p38、ERK mRNA表达的影响,免疫组化测定蒿藤胶囊对脾脏组织中JNK、p38、ERK蛋白表达的影响,Western blot法测定关节滑膜中JNK、ERK蛋白表达。结果：蒿藤胶囊0.193 g·kg^-1在给药14 d时可显著缓解CIA大鼠的关节肿胀率,降低病理学评分及血清炎症因子IL-17、IL-6的水平,抑制CD4⁺ T淋巴细胞升高,下调脾脏组织JNK、p38、ERK mRNA及JNK、ERK蛋白的表达并下调关节滑膜中JNK、ERK蛋白表达。结论：蒿藤胶囊治疗CIA大鼠的免疫抑制机制可能与下调脾脏组织与关节滑膜中JNK、ERK表达,降低外周血中CD4⁺ T淋巴细胞的比例与血清炎症因子IL-17、IL-6的水平有关。     

Elevated levels of soluble Endothelial protein C receptor in rheumatoid arthritis and block the therapeutic effect of protein C in collagen-induced arthritis

BackgroundEndothelial protein C receptor (EPCR) is a membranous protein that can be combined with a variety of ligands and plays important roles in anticoagulant and anti-inflammation. Recent reports have shown that surface EPCR expression on T cells is negatively associated with Th17 differentiation and is co-expressed with other immunosuppressive molecules, such as The programmed cell death 1 (PD-1) and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4). Hence, we hypothesized that EPCR may play a critical role in rheumatoid arthritis (RA) disease progression that is mediated by Th17 differentiation. In order to explore the role of EPCR on RA disease pathogenesis, we detected membranous EPCR (mEPCR) expression in CD4⁺ T cells and soluble EPCR (sEPCR) expression in the sera of RA patients.MethodsThe proportion of CD4⁺/EPCR⁺ T cells in the peripheral blood of RA patients was detected by flow cytometry, and the expression of sEPCR in the sera of RA patients was detected by enzyme-linked immunosorbent assay (ELISA). For in vitro experiments, protein C (PC) and EPCR recombinant proteins were used to block peripheral blood mononuclear cell (PBMC) activation and to detect Th17 differentiation. For in vivo experiments in DBA/1 mice with collagen-induced arthritis (CIA), we administered PC and EPCR recombinant proteins, monitored disease progression, and evaluated the role of EPCR in disease progression.ResultsThe proportion of CD4⁺/EPCR⁺ T cells in the peripheral blood of RA patients was lower than that of osteoarthritis (OA) patients, while the expression level of sEPCR in the sera of RA patients was concomitantly higher than that in OA patients. Subsequent analysis revealed that sEPCR expression was positively correlated with rheumatoid factors (RF) and other inflammatory indicators in RA patients. Further studies confirmed that sEPCR administration alleviated the progression of collagen-induced arthritis and partially blocked the therapeutic effect of PC in CIA mice.ConclusionSoluble EPCR is associated with RA disease progression and induces disease remission in CIA mice by inhibiting Th17 differentiation.