The Chinese medicinal herb decoction QRZSLXF enhances anti-inflammatory effect in TNBS-induced colitis via balancing Th17/Tregs differentiation

ETHNOPHARMACOLOGICAL RELEVANCE

Inflammatory bowel disease (IBD) is one of the most common chronic inflammatory illnesses of the gastrointestinal tract due to the imbalance of immune homeostasis of T helper cells and/or regulatory T cells (Tregs). The Traditional Chinese medicine herb has been clinically proven for use in the treatment of IBD but its possible mechanism remains unknown. The study aims to assess the effect of Chinese medicinal herb decoction QRZSLXF (Qing Re Zao Shi Liang Xue receipt) for the treatment of TNBS-induced experimental colitis in mice and explore its relevant mechanism involved in Th17 and Tregs.

MATERIALS AND METHODS

Mice colitis was induced by 50% 2,4,6-Trinitrobenzenesulfonic Acid (TNBS) ethanol solution weekly manner. These established model mice were divided into model control (0.8% NaCl treatment), FICZ, naphthoflavone (NaFTV), dexamethasone (DXM), and QRZSLXF (QrLx) groups. The colonoscopy, H&E staining, and immune staining were used to analyze the disease severity, inflammatory condition and Th17 or Treg related factors expression. High-performance liquid chromatography-mass spectrometry (HPLC/MS) was used to assess the content of FICZ in the colon tissues. Western blot and ELISA were used to examine the expression of Th17 or Treg related factors protein levels. Flow cytometry analysis was performed to assess the number and ratio of Th17/Tregs in splenocytes, and mesenteric lymph node lymphocytes (MLNCs), and lamina propria mononuclear cells (LPMCs).

RESULTS

NaFTV, DXM and QrLx groups intestinal inflammation scores were significantly lower than that in colitis model control and FICZ groups, while the IL-6, STAT3, and RORγt expression levels were significantly lower than those in the model control and FICZ groups. Mass spectrometry results showed FICZ that in both DXM and QrLx groups was lower than control model and FICZ groups. Flow cytometry results showed that DXM, NaFTV and QrLx could significantly reduce Th17 proportion and increase Treg proportion in splenocytes, MLNCs, and LPMCs.

CONCLUSIONS

NaFTV and QrLx treatment could decrease symptoms and inflammatory colitis, by decreasing of FICZ concentration and AhR signaling in colon, resulting in reducing the expression of IL-6, STAT3, and RORγt, whereas increasing the expression of FOXP3, consequently reducing the proportion of Th17 cells and increasing the proportion of Treg cells, respectively.

Zishen Tongluo formula ameliorates collagen-induced arthritis in mice by modulation of Th17/Treg balance

ETHNOPHARMACOLOGICAL RELEVANCE

Zishen Tongluo formula (ZTF) is simplified from the Qingluo Tongbi formula, which has been applied to treat rheumatoid arthritis (RA) in clinical practices for several decades. Our previous studies have verified the effects of ZTF on arthritis animal models. However, its mechanism of treating RA is not clear.

AIM OF THE STUDY

The present study was designed to investigate the effects of ZTF on the Th17/Treg balance in RA mice and the role of the different herb groups with the effect of Zishen yangyin (YY), Huatan quyu (HT), or Qufeng chushi (QF) in ZTF.

MATERIALS AND METHODS

A mouse model of collagen-induced arthritis (CIA) was established. The animals were randomly divided into the normal, model, positive drug, YY, QF, HT, and the whole compound (ZTF) groups. After oral administration for one-month, cytokine levels in the plasma and histopathological changes of the joint were measured by ELISA and hematoxylin-eosin staining, respectively. Meanwhile, the balance of Th17/Treg cells in blood, spleen or lymph nodes was detected using flow cytometry and qPCR.

RESULTS

ZTF or the different functional groups could improve the joint inflammation, decrease the levels of proinflammatory cytokines, restore the balance of Th17 and Treg cells in CIA mice. However, there were some differences in each functional group: YY mainly promoted the responses of Treg cells while QF inhibited the functions of Th17 cells. Besides, HT regulated both Th17 and Treg cells to keep the immune balance.

CONCLUSIONS

ZTF could notably ameliorate CIA mice by restoring the balance of Th17/Treg cells. Each functional group could target Th17 and/or Treg cells to produce synergistic/enhancement effects, and ZTF had a better holistic effect in RA treatment.

Exopolysaccharide Produced by Lactobacillus casei Promotes the Differentiation of CD4+ T Cells into Th17 Cells in BALB/c Mouse Peyer's Patches in Vivo and in Vitro

The immunomodulatory activity of a few Lactobacillus exopolysaccharides (EPS) has been reported. However, whether Lactobacillus EPS can promote the differentiation of CD4 T lymphocytes (CD4⁺T) cells into T-helper 17 cells (Th17 cells) in the Peyer's Patches (PPs) of mice has not been addressed. In this study, we found the molecular weight (M_w) of the purified EPS from L. casei ranged from 2.7 × 10⁶ Da to 1.7 × 10⁷ Da, and the average M_w was approximately 8.4 × 10⁶ Da. In healthy BALB/c mice, EPS elevated the numbers of Th17 cells and levels of Th17-related cytokines. In vitro, EPS induced BMDCs to stimulate the differentiation of CD4⁺T cells of PPs into Th17 cells and the related cytokine secretions. Results suggest that L. casei EPS can effectively induce and promote the differentiation of CD4⁺T cells of PPs into Th17 cells in healthy mice and has the potential ability to improve intestinal mucosa immunity.

The impact of bacteria-derived ultrafine dust particles on pulmonary diseases

The relationship between ambient particulate matter exposure and health has been well established. Ultrafine particles (UFP) with a diameter of 100 nm or less are known to increase pulmonary disease risk. Biological factors in dust containing UFP can cause severe inflammatory reactions. Pulmonary diseases develop primarily as a result of chronic inflammation caused by immune dysfunction. Thus, this review focuses on the adverse pulmonary effects of biological UFP, principally lipopolysaccharide (LPS), and bacterial extracellular vesicles (EVs), in indoor dust and the pathophysiological mechanisms involved in the development of chronic pulmonary diseases. The impact of LPS-induced pulmonary inflammation is based primarily on the amount of inhaled LPS. When relatively low levels of LPS are inhaled, a cascade of immune responses leads to Th2 cell induction, and IL-5 and IL-13 released by Th2 cells contributes to asthma development. Conversely, exposure to high levels of LPS induces a Th17 cell response, leading to increased production of IL-17, which is associated with asthma, COPD, and lung cancer incidence. Responses to bacterial EV exposure can similarly be broadly divided based on whether one of two mechanisms, either intracellular or extracellular, is activated, which depends on the type of the parent cell. Extracellular bacteria-derived EVs can cause neutrophilic inflammation via Th17 cell induction, which is associated with asthma, emphysema, COPD, and lung cancer. On the other hand, intracellular bacteria-derived EVs lead to mononuclear inflammation via Th1 cell induction, which increases the risk of emphysema. In conclusion, future measures should focus on the overall reduction of LPS sources in addition to the improvement of the balance of inhaled bacterial EVs in the indoor environment to minimize pulmonary disease risk.

Nrf2 Activator RTA-408 Protects Against Ozone-Induced Acute Asthma Exacerbation by Suppressing ROS and γδT17 Cells

Ozone is a strong oxidant in air pollution that exacerbates respiratory disorders and is a major risk factor for acute asthma exacerbation. Ozone can induce reactive oxygen species (ROS) and airway neutrophilic inflammation. In addition, γδT17 cells contribute to IL-17A production upon ozone challenge, resulting in neutrophilic inflammation. It is known, however, that Nrf2 can ameliorate oxidative stress. We therefore investigated whether RTA-408, an Nrf2 activator, can attenuate airway inflammation and inhibit ROS production and whether this effect involves γδT17 cells. Balb/c mice were sensitized/challenged with ovalbumin (OVA) and followed by ozone exposure. We investigated the effect of Nrf2 activator RTA-408 on airway hyperresponsiveness, neutrophilic airway inflammation, cytokine/chemokine production, and OVA-specific IgE level in a mouse model of O3 induced asthma exacerbation. Furthermore, malondialdehyde (MDA) and glutathione (GSH) levels in lung and intracellular ROS were measured. IL-17⁺ γδT cell percentage by flow cytometer was determined. Nrf2 protein expression by western blot was also examined. We observed that RTA-408 attenuated ROS release during ozone-induced asthma exacerbation and suppressed neutrophil lung infiltration. RTA-408 decreased pro-inflammatory cytokine production and reduced the percentage of IL-17⁺ γδT cells. Thus, our results suggest that RTA-408 does attenuate airway inflammation in a murine model of ozone-induced asthma exacerbation.

The Role of Th17-Related Cytokines in Atopic Dermatitis

T helper-17 (Th17) cells, which mainly produce IL-17, are associated with development of various autoimmune diseases such as rheumatoid arthritis, inflammatory bowel diseases, multiple sclerosis, and psoriasis. IL-17 and related cytokines are therapeutic targets of these diseases. In atopic dermatitis (AD), Th2 cytokines such as IL-4 and IL-13 are regarded to be the main player of the disease; however, Th17 cytokines are also expressed in AD skin lesions. Expression of IL-22 rather than IL-17 is predominant in AD skin, which is contrary to cytokine expression in psoriasis skin. Relatively low IL-17 expression in AD skin can induce relatively low antimicrobial peptide expression, which may be a reason why bacterial infection is frequently seen in AD patients. Failure of clinical trials for investigating the efficacy of anti-IL-12/23 p40 in AD has suggested that IL-17 expressed in skin lesions should not be the main player but a bystander responding to barrier dysfunction.

Salt Sensing by Serum/Glucocorticoid-Regulated Kinase 1 Promotes Th17-like Inflammatory Adaptation of Foxp3+ Regulatory T Cells

Regulatory T (Treg) cells integrate diverse environmental signals to modulate their function for optimal suppression. Translational regulation represents a favorable mechanism for Treg cell environmental sensing and adaptation. In this study, we carry out an unbiased screen of the Treg cell translatome and identify serum/glucocorticoid-regulated kinase 1 (SGK1), a known salt sensor in T cells, as being preferentially translated in activated Treg cells. We show that high salt (HS) drives thymic Treg cells to adopt a T helper type 17 (Th17)-like phenotype and enhances generation of Th17-like induced Treg cells in a SGK1-dependent manner, all the while maintaining suppressive function. Salt-mediated Th17-like differentiation of Treg cells was evident in mice fed with HS diet or injected with HS-preconditioned T cells. Overall, SGK1 enables Treg cells to adapt their function in response to environmental cues. By understanding these environmental-sensing mechanisms, we envision targeted approaches to fine-tune Treg cell function for better control of inflammation.

Neurokinin-1 Receptor Antagonism Ameliorates Dry Eye Disease by Inhibiting Antigen-Presenting Cell Maturation and T Helper 17 Cell Activation

Neuroinflammation plays an important role in the pathogenesis of ocular surface disease, including dry eye disease (DED), but little is known about the contribution of substance P (SP) to DED. In this study, we investigated the expression of SP at the ocular surface and evaluated its effect on maturation of antigen-presenting cells (APCs), the key cell component involved in the induction of type 17 helper T-cell (Th17) response in DED. The effect of topical blockade of SP signaling was further investigated using neurokinin-1 receptor (NK1R) inhibitors on APC maturation, Th17 cell activation, and disease severity in a mouse model of DED. The results demonstrate that SP is constitutively expressed at the ocular surface, and trigeminal ganglion neurons are the major source of SP in DED. SP derived from trigeminal ganglion enhanced the expression of major histocompatibility complex class II maturation marker by bone marrow-derived dendritic cells, an effect that is abrogated by blockade of SP signaling using NK1R antagonist spantide. Finally, using a well-established murine model of DED, topical treatment of DED mice with NK1R antagonists CP-99,994 and L-733,060 suppressed APC acquisition of major histocompatibility complex class II, reduced Th17 cell activity, and ameliorated DED severity. These findings are of translational value, as they suggest that antagonizing NK1R-mediated SP signaling may be an effective strategy in suppressing Th17-mediated ocular surface disease.

Protective effects of catalpol and rhein in murine experimental autoimmune encephalomyelitis via regulation of T helper (Th) 1, Th2, Th17, and regulatory T cell responses

OBJECTIVE

To examine the effects of catalpol and rhein on pro- and anti-inflammatory responses in C57BL/6 mice with experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis.

METHODS

Female C57BL/6 mice were randomly divided into four groups (n = 30): (a) normal saline control, (b) EAE control, (c) EAE + prednisone acetate (PA, 6 mg/kg), and (d) EAE + catalpol (40 mg/kg) and rhein (5 mg/kg). EAE was induced by injection of myelin oligodendrocyte glycoprotein 35-55 plus pertussis toxin. Treatments were orally administered daily for 40 d. Disease progression and neurological function were assessed using a semi-quantitative scale of tail and limb paralysis. Brains and spinal cords were collected on Days 6, 20, and 40 and assessed for histopathological changes by hematoxylin and eosin staining. Production of interleukin (IL)-2, IL-4, IL-10, and IL-17A protein was measured by enzyme-linked immunosorbent assay. Expression of the T helper (Th)1-, Th2-, Th17-, and regulatory T cell (Treg)-specific transcription factors T-bet, GATA3, ROR-γt, and Foxp3, respectively, were analyzed by quantitative reverse-transcription polymerase chain reaction and western blot analysis.

RESULTS

Combination treatment with catalpol and rhein significantly alleviated the clinical disability and neurological dysfunction of mice with EAE. Catalpol and rhein treatment also reduced the infiltration of pro-inflammatory T cells into pathological lesions; significantly increased the expression of the anti-inflammatory factors GATA3, Foxp3, IL-4, and IL-10; and significantly decreased the expression of the pro-inflammatory factors T-bet, ROR-γt, IL-2, and IL-17A.

CONCLUSION

Catalpol and rhein reduced the neurological disabilities of mice with EAE, at least in part by rebalancing the pro- and anti-inflammatory environment in the brains and spinal cords.

Oxymatrine protects against l-arginine-induced acute pancreatitis and intestine injury involving Th1/Th17 cytokines and MAPK/NF-κB signalling

Context: Oxymatrine (OMT) has various pharmacological effects, including immune reaction regulation, anti-inflammation and anti-hypersensitive reaction. Objective: This is the first report to investigate the molecular mechanism of OMT function in l-arginine (Arg)-induced acute pancreatitis (AP) involving intestinal injury. Materials and methods: Rat pancreatic AR42J and small intestinal IEC-6 cells were treated with Arg (200-800 µM) for 48 h plus OMT (4 mg/mL) treatment. Thirty adult Wistar rats were randomly assigned to control (saline), AP (i.p. of 250 mg/100 g body weight Arg) and OMT (i.p. injection of 50 mg/kg b.w. OMT every 6 h following Arg). Both cells and rats were harvested at 48 h. Results: Arg-induced cell proliferation in both rats AR42J (EC₅₀ 633.9 ± 31.4 µM) and IEC-6 cells (EC₅₀ 571.3 ± 40.4 µM) in a dose-dependent manner, which was significantly inhibited by OMT (4 mg/mL). Meanwhile, Arg (600 µM) induced expression of proinflammatory cytokines (TNF-α, IL-6, IL-1β, NF-κB, IL-17A/IL-17F and IFN-γ) and activation of p-p38/p-ERK in vitro, which was reversed by OMT. In vivo, OMT (50 mg/kg) inhibited 250 mg/100 g of Arg-induced AP involving intestinal injury, including inhibiting Arg-induced inflammatory in pancreas and intestine, inhibiting Arg-induced increase of TNF-α, IL-6, IL-1β, NF-κB and p-p38/p-ERK-MAPK signalling, and inhibiting Arg-induced increase of IL-17A/IL-17F, IFN-γ, ROR-γt and T-bet. Meanwhile, OMT inhibited Arg-induced expression of CD44 and CD55 in intestinal injury. Discussion and conclusions: OMT protects against Arg-induced AP involving intestinal injury via regulating Th1/Th17 cytokines and MAPK/NF-κB signalling, which is a promising therapeutic agent in clinics.

Anti-tumor necrosis factor treatment increases both the Th17 and Th22 T helper subsets in spondyloarthritis

The aim was to examine anti-tumor necrosis factor α (anti-TNFα) therapy influence changes on Th17 and Th22 cells in patients with spondyloarthritis (SpA), and its correlation with changes in clinical and magnetic resonance imaging (MRI) activity and chronicity scores. The Th17 and Th22 cells were assessed at baseline, after 12 and 52 weeks of anti-TNFα therapy by flow cytometry (ClinicalTrials.gov NCT4682724). The percentages of both Th17 and Th22 cells were increased by 70% at baseline compared with healthy controls (both p < 0.01). During treatment, these two subsets increased further to be 170% (Th17) and 123% (Th22) above levels in healthy controls (both p < 0.01). The same subsets decrease their expression of IL-23R significantly during the observation period (p < 0.05). High levels of Th17 and Th22 cells at baseline were associated with the degree of chronic changes in the sacroiliac joints on MRI and a good clinical response to anti-TNFα treatment after one year. Plasma levels were not associated with clinical changes. Th17 cells, and Th22 subsets, increased during one year of anti-TNF-α therapy in SpA, regardless of their clinical improvement. This supports that both the Th17 and Th22 subsets could be involved in the progression in SpA.

Circulating Th17.1 cells as candidate for the prediction of therapeutic response to abatacept in patients with rheumatoid arthritis: An exploratory research

T-helper (Th)17.1 cells exhibit high pathogenicity in inflammatory diseases. This study aimed to identify the changes in the proportions of Th subsets, including Th17.1, which are associated with abatacept treatment response in Japanese patients with rheumatoid arthritis. On the basis of the results, we assessed whether Th17.1 is a potential cellular biomarker. Multicolor flow cytometry was used to determine the circulating Th subsets among CD4+ T lymphocytes in 40 patients with rheumatoid arthritis before abatacept treatment. All the patients received abatacept treatment for 24 weeks; changes in disease activity score, including 28-joint count C-reactive protein, and responsiveness indicated by other indices to abatacept treatment were evaluated according the European League Against Rheumatism criteria (good and moderate responders and nonresponders). The correlation between the abatacept responses and the proportions of Th subsets (baseline) was analyzed. Logistic regression analysis with inverse probability weighting method was performed to calculate the odds ratio adjusted for patient characteristics. The proportion of baseline Th17.1 cells was significantly lower in patients categorized as good responders than in those categorized as non-good responders (moderate responders and nonresponders; p = 0.0064). The decrease in 28-joint count C-reactive protein after 24 weeks of abatacept therapy showed a significant negative correlation with the proportion of Th17.1 cells. The adjusted odds ratio for achieving good response in patients with baseline Th17.1 levels below the median value was 14.6 (95% confidence interval, 2.9–72.3; p = 0.0021) relative to that in the remaining patients. The proportion of Th17.1 cells at baseline is a good candidate for predicting abatacept treatment response in Japanese patients. These novel findings may represent a significant step in the pursuit of precision medicine.

Effect of IL-21 on the Balance of Th17 Cells/Treg Cells in the Pathogenesis of Graves' Disease

Graves' disease (GD) is a common organ-specific autoimmune disease, and its pathogenesis is still unclear. The aim of this study is to investigate the role of interleukin (IL)-21 in the regulation of Th17/Treg cells in GD. We recruited 28 newly diagnosed GD patients, 27 GD patients in remission (eGD), and 24 normal controls (NC). Thyroid function and autoantibodies were evaluated by electrochemical luminescence. Peripheral blood mononuclear cells (PBMCs) were isolated and cultured with or without recombinant human interleukin-21 (rhIL-21), and mRNA and protein levels were quantified by real-time PCR and ELISA, respectively. Compared with those in the eGD and control groups, the thyroid function indexes and autoantibodies levels were significantly different in the GD group (P < 0.05). Without rhIL-21 stimulation, the expression levels of retinoid-related orphan gamma t (RORγt), IL-17, IL-22, forkhead box protein P3 (Foxp3) and IL-10 mRNA and the IL-10 and IL-22 proteins were significantly higher in the GD group than those in the eGD and control groups (P < 0.05). rhIL-21 stimulation increased the RORγt, IL-17, and IL-22 mRNA levels and IL-22 protein levels and decreased the Foxp3 and IL-10 mRNA levels and IL-10 protein levels (P < 0.05) in the GD group. In conclusion, our analyses demonstrated that IL-21 might induce the differentiation of CD4⁺ T cells to Th17 cells and reduce Treg cell differentiation, which could contribute to activation of the downstream immune response and the pathogenesis of GD.

Tangeretin attenuates lipopolysaccharide-induced acute lung injury through Notch signaling pathway via suppressing Th17 cell response in mice

Tangeretin, a polymethoxylated flavonoid is abundant in citrus fruits, which has been reported to inhibit inflammation by inhibiting NF-κB activation and proinflammatory cytokines. Notch blockage inhibits Th17 cells response that are involved in the development of acute lung injury (ALI). This study investigated the protective effects of tangeretin on LPS-induced ALI in mice. Male C57BL/6 mice were treated with phosphate-buffered saline (PBS), lipopolysaccharide (LPS), LPS and tangeretin, or LPS and N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT, a Notch signaling inhibitor), which were harvested at 48 h after challenged by LPS. CD4⁺ T cells were treated with tangeretin or DAPT and harvested after 72 h. Tangeretin notably attenuated pathological changes and decreased the wet to dry weight ratio of the mouse lungs. The total cell and neutrophil counts, tumor necrosis factor (TNF)-α in bronchoalveolar lavage fluid (BALF), myeloperoxidase activity of lung tissue were markedly reduced by tangeretin. The percentage of CD4+IL-17 + T cells in the lungs and the concentration of interleukin (IL)-17 and IL-22 in BALF were significantly down-regulated by tangeretin. As with the positive control (DAPT), tangeretin inhibited the activity of the Notch signaling pathway accompanied with the down-regulation of acid-related orphan receptor gamma t and IL-23 receptor expression. This study demonstrated that tangeretin protects against LPS-induced ALI by suppressing Th17 response at least partially, through a Notch-dependent mechanism.

Anti-psoriasis effect of water-processed rosin in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Rosin, an exudate of conifer trees such as Pinus masscnlana (Pinaceae), has been used to treat psoriasis for nearly two thousand years in China despite its so far undefined pharmacology. Unfortunately, the rosin intoxication is noted from time to time, but the water-boiled rosin (WBR) has been documented to be safer. This study was performed to evaluate the in vivo anti-psoriasis efficacy of WBR.

MATERIALS AND METHODS

The main phytochemicals in WBR were quantified by high performance liquid chromatography (HPLC). WBR was evaluated in the imiquimod-induced psoriasis-like inflammation mouse model for its anti-psoriasis effect at 130, 260, and 390 mg/kg, which were set according to the dose used for patients. Through a combination of q-PCR, flow cytometry, and histopathological and immunohistochemical (IHC) analysis, the in vivo efficacy was assessed in terms of the psoriasis area severity index (PASI), epidermal keratinocyte proliferation, Th1 and Th17 cell numbers in spleen, and mRNA expressions of inflammatory cytokines.

RESULT

Oral administration of WBR ameliorates the psoriasis-like dermatitis in the imiquimod-generated mouse model. In particular, WBR given at 260 or 390 mg/kg significantly restores the normal keratinization of dorsal lesion if compared with the untreated psoriatic mice. Such an effect was addressed to correlate to the Th1/Th17 cell reduction in spleen and the suppressed expression of IL-17A, IL-17F, IL-22, IL-23, TNF-α, K17, and proliferating cell nuclear antigen (PCNA) after the WBR administration.

CONCLUSION

WBR is effective in the imiquimod-induced psoriasis-like inflammation mouse model with the efficacy arising from its proliferation inhibition of Th1/Th17 cells and epidermal keratinocytes via the down-regulation of the relevant inflammatory cytokines such as IL-23, IL-17A, and IL-17F. Collectively, WBR harvested and processed in the traditional manner is an efficacious psoriasis-treating agent.

Inhibitory effect of α-amyrin acetate isolated from Fraxinus rhynchophylla on Th17 polarization

BACKGROUND

T helper 17 (Th17) cells, which are differentiated from CD4⁺ T cells, drive inflammation, leading to autoimmune diseases such as psoriasis, rheumatoid arthritis, and inflammatory bowel disease. Therefore, inhibiting Th17 polarization could be a therapeutic target for inflammatory diseases.

PURPOSE

We investigated the inhibitory effect of Fraxinus rhynchophylla (Oleaceae) on Th17 differentiation and found its active component.

STUDY DESIGN

The activity of F. rhynchophylla and its active constituent was verified using CD4⁺ cells extracted from C57BL/6 mice.

METHODS

Micro-environment for Th17 polarization was provided to CD4⁺ cells and the effect of treatment with samples was measured by enzyme linked immunosorbent assay (ELISA), polymerase chain reaction (PCR), and Western blot.

RESULTS

The extract of F. rhynchophylla Hance and its chemical constituent, α-amyrin acetate, which was isolated via bioassay-guided isolation, significantly inhibited Th17 polarization as revealed when interleukin (IL)-17, a characteristic cytokine produced by Th17 cells, was measured. Furthermore, the inhibitory effect of α-amyrin acetate was compared to the amyrin derivatives, α-amyrin and β-amyrin. All displayed a suppressive effect on Th17 polarization and all reduced the expression of single transducer and activator of transcription 3 (STAT3) and retinoic acid receptor-related orphan receptor γt (RORγt), which are crucial transcription factors regulating Th17 differentiation. α-Amyrin acetate, however, exhibited the most prominent effects, which indicates that the functional group, acetate, might strengthen the inhibitory effect on Th17 differentiation.

CONCLUSION

Taken together, these results suggest that the extract of F. rhynchophylla and its active constituent, α-amyrin acetate, could be applied as a potential therapeutic agent for autoimmune disorders such as rheumatoid arthritis.

Immunomodulatory effect of thymopentin on lymphocytes from supramammary lymph nodes of dairy cows

Previous study showed that injection of thymopentin (TP 5) in the area of supramammary lymph nodes (SMLN) had therapeutic effect on the intramammary infection (IMI) in cows. This study was to explore the underlying mechanisms by investigating the immunomodulatory effect of TP 5 on SMLN lymphocytes. Lymphocyte proliferation, cell cycle distribution and cytokine mRNA expression were determined by MTT, FCM and RT-qPCR, respectively. Laser scanning confocal microscope (LSCM) was used to observe the binding between TP 5 and SMLN lymphocytes. Moreover, RNA-sequencing (RNA-seq) was performed to observe the difference between the lymphocytes with and without TP 5 treatment. The results showed that TP 5 significantly promoted lymphocyte proliferation, accelerated cell cycle progression, and enhanced mRNA expression of IL-17A and IL-17F. Laser scanning confocal microscopic analysis revealed the binding of TP 5 to the surface of SMLN lymphocytes. A total of 1094 genes were identified as differentially expressed genes (DEGs) using RNA-seq with 692 up- and 402 down-regulated genes. 48 significantly enriched GO terms were identified by RNA-seq. In KEGG analysis, 1/3 of DEGs were enriched in the immune system pathway, including IL-17 signaling pathway, cytokine-cytokine receptor interaction, Th1 and Th2 cell differentiation, T cell receptor signaling pathway, Th17 cell differentiation. Among them, IL-17 signaling pathway was the most prominent. This study suggested that the therapeutic benefit of TP 5 in the treatment of bovine mastitis might be attributed to its immunomodulatory activity in SMLN lymphocytes.

Antagonistic effect of vitamin E on nAl2O3-induced exacerbation of Th2 and Th17-mediated allergic asthma via oxidative stress

Some basic research has shown that nanomaterials can aggravate allergic asthma. However, its potential mechanism is insufficient. Based on the research that alumina nanopowder (nAl₂O₃) has been reported to cause lung tissue damage, the purpose of this study was to explore the relationship between nAl₂O₃ and allergic asthma as well as its molecular mechanism. In this study, Balb/c mice were sensitized with ovalbumin (OVA) to construct the allergic asthma model while intratracheally administered 0.5, 5 or 50 mg kg^-1·day^-1 nAl₂O₃ for 3 weeks. It was observed that exposure to nAl₂O₃ exacerbated airway hyperresponsiveness (AHR), airway remodeling, and inflammation cell infiltration, leading to lung function damage in mice. Results revealed that nAl₂O₃ could increase ROS levels and decrease GSH levels in lung tissue, promote the increases of the T-IgE, TGF-β, IL-1β and IL-6 levels, stimulate the overexpression of transcription factors GATA-3 and RORγt, decrease the levels of IFN-γ and IL-10 and increase the levels of IL-4 and IL-17A, resulting in the imbalance of Th1/Th2 and Treg/Th17 immune responses. In addition, antioxidant Vitamin E (Vit E) could alleviate asthma-like symptoms through blocking oxidative stress. The study displayed that exposure of nAl₂O₃ deteriorated allergic asthma through promoting the imbalances of Th1/Th2 and Treg/Th17.

Effectiveness of methotrexate in combination therapy in a rat collagen-induced arthritis model

This study was to investigate the effect of methotrexate in combination therapy by the characteristic cytokine in Th17 cells and the frequency of Tregs, which involved in the induction and pathological progress of rheumatoid arthritis (RA). The collagen-induced arthritis rats were treated with methotrexate + prednisone, methotrexate + disease-modifying rheumatic drugs (DMARDs) and methotrexate + TNFi, respectively. The following parameters were observed to evaluate three treatments: the frequency and function of Th17 cells and Tregs, the scores of X-rays, H&E staining and immunohistochemistry. For rats starting methotrexate + prednisone (low doses), the frequency and suppressive function of Th17 cells decreased while the frequency of Tregs increased, which were the same in methotrexate + TNFi. Immunohistochemical in the pathological sections of ankle joint showed the same results. The effect of methotrexate + DMARDs treatment was slightly inferior to the other combination therapies. In summary, rats treated with methotrexate + prednisone can achieve high level of Tregs and low level of Th17 cells and IL-17. Low doses of glucocorticoid suggesting a critical role in the pathogenesis of rheumatoid arthritis may have the similar effect as DMARDs.

Low-molecular-weight-heparin increases Th1- and Th17-associated chemokine levels during pregnancy in women with unexplained recurrent pregnancy loss: a randomised controlled trial

Low-molecular-weight heparin (LMWH) is widely used to treat recurrent pregnancy loss (RPL) because of its anti-coagulant effects. Although in vitro studies have suggested additional immunological effects, these are debated. We therefore investigated whether LMWH could modulate immune responses in vivo during pregnancy of women with unexplained RPL. A Swedish open multi-centre randomised controlled trial included 45 women treated with tinzaparin and 42 untreated women. Longitudinally collected plasma samples were obtained at gestational weeks (gw) 6, 18, 28 and 34 and analysed by multiplex bead technology for levels of 11 cytokines and chemokines, chosen to represent inflammation and T-helper subset-associated immunity. Mixed linear models test on LMWH-treated and untreated women showed differences during pregnancy of the Th1-associated chemokines CXCL10 (p = 0.01), CXCL11 (p < 0.001) and the Th17-associated chemokine CCL20 (p = 0.04), while CCL2, CCL17, CCL22, CXCL1, CXCL8, CXCL12, CXCL13 and IL-6 did not differ. Subsequent Student's t-test showed significantly higher plasma levels of CXCL10 and CXCL11 in treated than untreated women at gw 28 and 34. The consistent increase in the two Th1-associated chemokines suggests a potential proinflammatory and unfavourable effect of LMWH treatment during later stages of pregnancy, when Th1 immunity is known to disrupt immunological tolerance.

Anti-IL-17A and IL-23p19 antibodies but not anti-TNFα antibody induce expansion of regulatory T cells and restoration of their suppressive function in imiquimod-induced psoriasiform dermatitis

BACKGROUND

Psoriasis is a chronic inflammatory skin disease. Anti-TNFα, IL-17A and IL-23p19 antibodies are effective for psoriasis. However, the contribution of regulatory T cells (Treg) in their effectiveness remains to be elucidated.

OBJECTIVE

We investigated the effects of TNFα, IL-17A and IL-23p19 inhibition on Tregs in imiquimod-induced psoriasiform dermatitis.

METHODS

Psoriasiform dermatitis was induced by imiquimod application on murine shaved back skin for six days. Mice were treated with anti-TNFα, IL-17A or IL-23p19 monoclonal antibodies every other day from one day before imiquimod application.

RESULTS

Administration of anti-TNFα, IL-17A or IL-23p19 antibodies improved the clinical score and downregulated Th17-related cytokines and chemokines, while IL-23p19 antibodies upregulated IL-10 mRNA expression. Anti-IL-17A or IL-23p19 antibody-treated imiquimod-applied mice showed a significant increase in the number of Foxp3⁺ IL-10⁺ Tregs. Recipient mice adoptively transferred with Tregs derived from donor mice treated with antibodies demonstrated clinical and pathological improvement in imiquimod-induced psoriasiform dermatitis. Anti-IL-17A or IL-23p19 antibody-induced Tregs significantly increased the number of Foxp3⁺ cells and IL-10 expression in imiquimod-induced psoriasiform dermatitis in recipient mice but anti-TNFα antibody-induced Tregs did not.

CONCLUSION

Anti-IL-17A or IL-23p19 antibody inhibits the IL-17/IL-23 signaling pathway, and induces expansion of Tregs and their suppressive capacity in imiquimod-induced psoriasiform dermatitis.

Pyruvate kinase M2 is requisite for Th1 and Th17 differentiation

Th1 and Th17 are important in the pathogenesis of autoimmune diseases and they depend on glycolysis as a source of energy. T cell antigen receptor signaling phosphorylates a serine/threonine kinase, calcium/calmodulin-dependent protein kinase IV (CaMK4), and promotes glycolysis. Based on these findings we hypothesized that CaMK4 promotes glycolysis. Camk4-deficient CD4+ T cells and cells treated with a CaMK4 inhibitor had less glycolysis compared with their counterparts. Pull-down of CaMK4 and mass spectrometry identified pyruvate kinase muscle isozyme (PKM), the final rate-limiting enzyme in glycolysis, as a binding partner. Coimmunoprecipitation and Western blotting showed that CaMK4 interacts directly with PKM2. Camk4-deficient CD4+ T cells displayed decreased pyruvate kinase activity. Silencing or pharmacological inhibition of PKM2 reduced glycolysis and in vitro differentiation to Th1 and Th17 cells, while PKM2 overexpression restored Th17 cell differentiation. Treatment with a PKM2 inhibitor ameliorated experimental autoimmune encephalomyelitis and CD4+ T cells treated with PKM2 inhibitor or Pkm2-shRNA caused limited disease activity in an adoptive cell transfer model of experimental autoimmune encephalomyelitis. Our data demonstrate that CaMK4 binds to PKM2 and promotes its activity, which is requisite for Th1 and Th17 differentiation in vitro and in vivo. PKM2 represents a therapeutic target for T cell-dependent autoimmune diseases.

Potential Mechanisms of T Cell-Mediated and Eosinophil-Independent Bronchial Hyperresponsiveness

Bronchial asthma is a chronic disease characterized by reversible airway obstruction, mucus production, and bronchial hyperresponsiveness (BHR). Although Th2 cell-mediated eosinophilic inflammation is an important disease mechanism in the majority of patients with bronchial asthma, recent studies suggest the possible development of Th2-independent airway inflammation and BHR. These non-Th2 endotype patients seem to consist of multiple subgroups, and often do not respond to inhaled corticosteroids. Therefore, to understand the pathogenesis of asthma, it is important to characterize these non-Th2 subgroups. Recently, we demonstrated that Th9 cells induce eosinophil infiltration and eosinophil-independent BHR, and Th9 cells-mediated BHR may be resistant to glucocorticoid. In this review, we summarize the contribution of several T cell subsets in the development of bronchial asthma and introduce our recent study demonstrating Th9 cell-mediated and eosinophil-independent BHR.

Dynamic Alterations in the Gut Microbiota of Collagen-Induced Arthritis Rats Following the Prolonged Administration of Total Glucosides of Paeony

Rheumatoid arthritis (RA) is a common autoimmune disease linked to chronic inflammation. Dysbiosis of the gut microbiota has been proposed to contribute to the risk of RA, and a large number of researchers have investigated the gut-joint axis hypothesis using the collagen-induced arthritis (CIA) rats. However, previous studies mainly involved short-term experiments; very few used the CIA model to investigate changes in gut microbiota over time. Moreover, previous research failed to use the CIA model to carry out detailed investigations of the effects of drug treatments upon inflammation in the joints, hyperplasia of the synovium, imbalance in the ratios of Th1/Th2 and Th17/Treg cells, intestinal cytokines and the gut microbiota following long-term intervention. In the present study, we carried out a 16-week experiment to investigate changes in the gut microbiota of CIA rats, and evaluated the modulatory effect of total glucosides of paeony (TGP), an immunomodulatory agent widely used in the treatment of RA, after 12 weeks of administration. We found that taxonomic differences developed in the microbial structure between the CIA group and the Control group. Furthermore, the administration of TGP was able to correct 78% of these taxonomic differences, while also increase the relative abundance of certain forms of beneficial symbiotic bacteria. By the end of the experiment, TGP had reduced body weight, thymus index and inflammatory cell infiltration in the ankle joint of CIA rats. Furthermore, the administration of TGP had down-regulated the synovial content of VEGF and the levels of Th1 cells and Th17 cells in CIA rats, and up-regulated the levels of Th2 cells and Treg cells. The administration of TGP also inhibited the levels of intestinal cytokines, secretory immunoglobulin A (SIgA) and Interferon-γ (IFN-γ). In conclusion, the influence of TGP on dynamic changes in gut microbiota, along with the observed improvement of indicators related to CIA symptoms during 12 weeks of administration, supported the hypothesis that the microbiome may play a role in TGP-mediated therapeutic effects in CIA rats. The present study also indicated that the mechanism underlying these effects may be related to the regulation of intestinal mucosal immunity remains unknown and deserves further research attention.

Indole alkaloids indigodoles A-C from aerial parts of Strobilanthes cusia in the traditional Chinese medicine Qing Dai have anti-IL-17 properties

Qing Dai (Naturalis Indigo) is a traditional Chinese medicine (TCM) used as a topical agent in moderate psoriasis, targeting interleukin-17 (IL-17). In this study, it was prepared from the aerial parts of Strobilanthes cusia. Three undescribed indole alkaloid derivatives, indigodoles A-C, along with seven known compounds were isolated from this preparation of Qing Dai and their structures were elucidated from spectroscopic data, including NMR, MS, UV, IR, optical rotation, and CD. As well, most compounds were tested against IL-17. Indigodole C and tryptanthrin could significantly inhibit IL-17 production of Th17 cells. In addition, indigodole A and indirubin showed notably anti-IL-17 gene expression in dose-dependent effects without cytotoxicities toward Th17 and Jurkat cells, respectively. Overall, our studies indicate that the aforementioned indole alkaloids could contribute to anti-IL 17 properties of Qing Dai.

Wuchereria bancrofti filaria activates human dendritic cells and polarizes T helper 1 and regulatory T cells via toll-like receptor 4

Interaction between innate immune cells and parasite plays a key role in the immunopathogenesis of lymphatic filariasis. Despite being professional antigen presenting cells critical for the pathogen recognition, processing and presenting the antigens for mounting T cell responses, the dendritic cell response and its role in initiating CD4+ T cell response to filaria, in particular Wuchereria bancrofti, the most prevalent microfilaria is still not clear. Herein, we demonstrate that a 70 kDa phosphorylcholine-binding W. bancrofti sheath antigen induces human dendritic cell maturation and secretion of several pro-inflammatory cytokines. Further, microfilarial sheath antigen-stimulated dendritic cells drive predominantly Th1 and regulatory T cell responses while Th17 and Th2 responses are marginal. Mechanistically, sheath antigen-induced dendritic cell maturation, and Th1 and regulatory T cell responses are mediated via toll-like receptor 4 signaling. Our data suggest that W. bancrofti sheath antigen exploits dendritic cells to mediate distinct CD4+ T cell responses and immunopathogenesis of lymphatic filariasis.

Rebamipide ophthalmic solution modulates the ratio of T helper cell 17/regulatory T cells in dry eye disease mice

The aim of the present study was to confirm the effect of 2% rebamipide ophthalmic solution on a scopolamine‑induced dry eye (DE) mouse model, and to investigate its effect on the ratio of T helper cell 17 (Th17)/regulatory T cell (Treg) numbers. C57BL/6 mice received subcutaneous injections of scopolamine and were exposed to a low‑humidity environment in order to establish a DE model. Rebamipide eye drops (2%) administered four times daily for 2 weeks, significantly reduced the corneal staining scores and increased the tear film breakup time and tear production in the DE mice. Pathologically, the rebamipide restored the histological changes induced by DE in the cornea, conjunctiva and lacrimal gland. At a molecular level, it downregulated pro‑inflammatory and upregulated anti‑inflammatory cytokines in the conjunctiva and lacrimal gland. Furthermore, the increased Th17 and Treg levels were restored following treatment with rebamipide. In conclusion, the anti‑inflammatory and Th17/Treg balance‑preserving effects of rebamipide may contribute to the treatment of DE in mice.

Dulaglutide Modulates the Development of Tissue-Infiltrating Th1/Th17 Cells and the Pathogenicity of Encephalitogenic Th1 Cells in the Central Nervous System

GLP-1 (glucagon-like peptide-1) has been reported to play a vital role in neuroprotection. Experimental autoimmune encephalomyelitis (EAE) is a well-established animal model widely used to study human multiple sclerosis, a chronic demyelination disease in the central nervous system (CNS). Recently, important studies have designated that the signaling axis of GLP-1 and its receptor controls the clinical manifestations and pathogenesis of EAE. However, it is elusive whether GLP-1 receptor signaling regulates the phenotype of autoreactive T cells in the CNS. We administered dulaglutide, a well-established GLP-1 receptor agonist (GLP-1 RA), to treat EAE mice prophylactically or semi-therapeutically and subsequently analyzed the mononuclear cells of the CNS. In this study, dulaglutide treatment significantly alleviates the clinical manifestations and histopathological outcomes of EAE. Dulaglutide decreases incidences of encephalitogenic Th1/Th17 cells and Th1 granulocyte-macrophage-colony-stimulating factor (GM-CSF) expression in the CNS. Administration of dulaglutide failed to control the chemotactic abilities of encephalitogenic Th1 and Th17 cells; however, prophylactic treatment considerably decreased the populations of dendritic cells and macrophages in the CNS parenchyma. These results obtained indicate that dulaglutide modulates the differentiation of encephalitogenic Th1/Th17 and the pathogenicity of Th1 cells by influencing antigen presenting cells quantities, providing mechanism insight on T cells regulation in ameliorating EAE by GLP-1.

Anti-tumor necrosis factor α therapy associates to type 17 helper T lymphocytes immunological shift and significant microbial changes in dextran sodium sulphate colitis

BACKGROUND

Anti-tumor necrosis factor α (TNFα) represents the best therapeutic option to induce mucosal healing and clinical remission in patients with moderate-severe ulcerative colitis. On the other side gut microbiota plays a crucial role in pathogenesis of ulcerative colitis but few information exists on how microbiota changes following anti-TNFα therapy and on microbiota role in mucosal healing.

AIM

To elucidate whether gut microbiota and immune system changes appear following anti TNFα therapy during dextran sulfate sodium (DSS) colitis.

METHODS

Eighty C57BL/6 mice were divided into four groups: “No DSS”, “No DSS + anti-TNFα”, “DSS” and “DSS + anti-TNFα”. “DSS” and “DSS + anti-TNFα” were treated for 5 d with 3% DSS. At day 3, mice whithin “No DSS+anti-TNFα” and “DSS+anti-TNFα” group received 5 mg/kg of an anti-TNFα agent. Forty mice were sacrificed at day 5, forty at day 12, after one week of recovery post DSS. The severity of colitis was assessed by a clinical score (Disease Activity Index), colon length and histology. Bacteria such as Bacteroides, Clostridiaceae, Enterococcaceae and Fecalibacterium prausnitzii (F. prausnitzii) were evaluated by quantitative PCR. Type 1 helper T lymphocytes (Th1), type 17 helper T lymphocytes (Th17) and CD4⁺ regulatory T lymphocytes (Treg) distributions in the mesenteric lymph node (MLN) were studied by flow cytometry.

RESULTS

Bacteria associated with a healthy state (i.e., such as Bacteroides, Clostridiaceae and F. prausnitzii) decreased during colitis and increased in course of anti-TNFα treatment. Conversely, microorganisms belonging to Enterococcaceae genera, which are linked to inflammatory processes, showed an opposite trend. Furthermore, in colitic mice treated with anti-TNFα microbial changes were associated with an initial increase (day 5 of the colitis) in Treg cells and a consequent decrease (day 12 post DSS) in Th1 and Th17 frequency cells. Healthy mice treated with anti-TNFα showed the same histological, microbial and immune features of untreated colitic mice. “No DSS + anti-TNFα” group showed a lymphomononuclear infiltrate both at 5^th and 12^th d at hematoxylin and eosin staining, an increase of in Th1 and Th17 frequency at day 12, an increase of Enterococcaceae at day 5, a decrease of Bacteroides and Clostridiaceae at day 12.

CONCLUSION

Anti-TNFα treatment in experimental model of colitis improves disease activity but it is associated to an increase in Th17 pathway together with gut microbiota alteration.

Effects of dioscin on T helper 17 and regulatory T-cell subsets in chicken collagen type II-induced arthritis mice

BACKGROUND

This study was conducted to investigate the treatment efficacies and immunological mechanisms of action of dioscin in mice with chicken collagen type II-induced arthritis (CIA).

METHODS

The CIA mice was randomly divided into the model group (M), dioscin group (D), and tripterygium group (T); a normal control group (C) was also included. Each group was orally administered with related drugs or an equal volume of solvent (group C) starting on the 21st day of primary immunity, after which the levels of T helper 17 cells (Th17), regulatory T cells (Tregs), and their related factors were detected on the 35th day.

RESULTS

Compared to group C, group M exhibited significantly increased levels of interleukin 17 (IL-17) and IL-6 and decreased IL-27 (p < 0.05). Group D exhibited significantly decreased levels of IL-17 and IL-6 compared with group M (p < 0.05). Group M showed a significantly increased ratio of Th17 cells (p < 0.05), while dioscin significantly reduced this ratio (p < 0.05). Groups M and C showed no significant difference in the ratio of Tregs (p > 0.05) but dioscin significantly increased this ratio (p < 0.05). Group M significantly increased signal transducer and activator of transcription 3 (STAT3) and STAT5 compared with that in group C (p < 0.05), while the T and D groups showed significantly reduced levels of STAT3 and STAT5 (p < 0.05).

CONCLUSION

Dioscin may affect the differentiation of Th17 and Tregs and secretion of related factors by regulating CD4 T cell subset-related signal transduction and the expression of transcription-activating factor STAT3 and STAT5, thus exerting useful immunoregulatory roles in CIA mice.

BATF Interference Blocks Th17 Cell Differentiation and Inflammatory Response in Hepatitis B Virus Transgenic Mice

BACKGROUND

B cell-activating transcription factor (BATF) contributes to Th17 cell differentiation and pathological inflammatory responses.

AIMS

This study explored BATF as a regulator of Th17 differentiation in normal and hepatitis B virus (HBV) transgenic mice.

METHODS

Normal mice were divided into control, short hairpin RNA (shRNA) scramble, and shRNA BATF groups. HBV transgenic mice were divided into control, entecavir, shRNA scramble, entecavir + vector control, entecavir + shRNA scramble, shRNA BATF, and entecavir + shRNA BATF groups. Serum concentrations of AST, ALT, HBV-DNA, BATF, IL-17, and IL-22 and Th17 cell frequencies in the liver were compared among the groups. Correlations of serum HBV surface antigen (HBsAg), e-antigen (HBeAg), and core antigen (HBcAg) concentrations with BATF mRNA expression and the proportion of Th17 cells in the livers of HBV transgenic mice were also analyzed.

RESULTS

Serum AST, ALT, BATF, IL-17, and IL-22 concentrations and Th17 cell proportions were higher in HBV transgenic mice relative to normal controls. Positive correlations of the HBcAg concentration with BATF mRNA and the proportion of Th17 cells were observed in HBV transgenic mice. BATF interference reduced the proportion of Th17 cells and serum IL-17 and IL-22 concentrations and led to obvious downregulation of AST, ALT, BATF, IL-17, and IL-22 expression and a reduced proportion of Th17 cells when combined with entecavir.

CONCLUSION

HBV markedly upregulated BATF expression and promoted Th17 cell activation. By contrast, BATF interference significantly impeded the proliferation of Th17 cells and secretion of IL-17 and IL-22 while alleviating hepatic lesions.

Rhubarb Peony Decoction ameliorates ulcerative colitis in mice by regulating gut microbiota to restoring Th17/Treg balance

ETHNOPHARMACOLOGY RELEVANCE

Rhubarb Peony Decoction (RPD) is a formula of traditional Chinese medicine chronicled in Jin Gui Yao Lve, commonly used to treat ulcerative colitis (UC). However, the underlying mechanism of RPD treating UC remains elusive. In our study, we investigated the therapeutic efficacy of RPD and potential mechanism involved in inhibiting dextran sulfate sodium (DSS)-induced ulcerative colitis in mice.

METHODS

The colitis was induced by DSS in mice for 5 days and estimated body weight loss, disease activity index (DAI) and colon length. Histological changes were observed by H&E staining. The number and abundance of gut mircrobiota were measured with 16 S rDNA sequencing. GC-MS was used to detect the concentration of short chain fatty acids (SCFAs) in cecum. Flow cytometry analyzed the proportion of Th17 and Treg cells in mesenteric lymph nodes (MLNs). IL-17A and Foxp3 in colon were determined by immunohistochemical analyses. The level of cytokine was determined by Multi-Analyte Flow Assay Kit.

RESULTS

Administration of RPD significantly alleviated the pathological changes of UC mice, involving rescued the inflammation-related reduction of colon length, ameliorated body weight loss and damaged tissue. In addition, RPD altered the gut microbiota, involving restored α diversity, increased significantly the abundance of Firmicutes and Actinobacteria, decreased the Proteobacteria and Bacteroidetes. Furthermore, the number of Butyricicoccus pullicaecorum, a butyrate-producing bacterium, were augmented obviously by RPD. Besides, RPD restored the content of SCFA in intestinal tract. Additionally, the proportion of Th17 cells and Treg cells in mesenteric lymph nodes, likewise, the expression of IL-17A and Foxp3 in colon were regulated by RPD, contributing to the restoration of Th17/Treg balance. Moreover, RPD significantly decreased the level of IL-6, TNF-α, IFNγ, IL-10, IL-17A, IL-21, IL-22 in colon, simultaneously increased Treg-related cytokine TGF-β at dose-dependently.

CONCLUSIONS

These results demonstrated that RPD had effect on ulcerative colitis, which was related to regulating gut microbiota, especially Butyricicoccus pullicaecorum, and SCFAs to restore the gut Th17/Treg homeostasis.

N-acetyl-l-cysteine controls osteoclastogenesis through regulating Th17 differentiation and RANKL production in rheumatoid arthritis

BACKGROUND/AIMS

This study aimed to determine the regulatory role of N-acetyl-l-cysteine (NAC), an antioxidant, in interleukin 17 (IL-17)-induced osteoclast differentiation in rheumatoid arthritis (RA).

METHODS

After RA synovial fibroblasts were stimulated by IL-17, the expression and production of receptor activator of nuclear factor κ-B ligand (RANKL) was determined by real-time polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA). Osteoclastogenesis was also determined after co-cultures of IL-17-stimulated RA synovial fibroblasts, Th17 cells and various concentrations of NAC with monocytes. After human peripheral CD4+ T cells were cultured with NAC under Th17 condition, IL-17, interferon γ, IL-4, Foxp3, RANKL, and IL-2 expression and production was determined by flow cytometry or ELISA.

RESULTS

When RA synovial fibroblasts were stimulated by IL-17, IL-17 stimulated the production of RANKL, and NAC reduced the IL-17-induced RANKL production in a dose-dependent manner. NAC decreased IL-17-activated phosphorylation of mammalian target of rapamycin, c-Jun N-terminal kinase, and inhibitor of κB. When human peripheral blood CD14+ monocytes were cultured with macrophage colony-stimulating factor and IL-17 or RANKL, osteoclasts were differentiated, and NAC reduced the osteoclastogenesis. After human peripheral CD4+ T cells were co-cultured with IL-17-pretreated RA synovial fibroblasts or Th17 cells, NAC reduced their osteoclastogenesis. Under Th17 polarizing condition, NAC decreased Th17 cell differentiation and IL-17 and RANKL production.

CONCLUSION

NAC inhibits the IL-17-induced RANKL production in RA synovial fibroblasts and IL-17-induced osteoclast differentiation. NAC also reduced Th17 polarization. NAC could be a supplementary therapeutic option for inflammatory and bony destructive processes in RA.

Sodium Chloride Aggravates Arthritis via Th17 Polarization

PURPOSE

Sodium chloride (NaCl) has been proposed as a driving factor in autoimmune diseases through the induction of pathogenic CD4⁺ T helper cells that produce interleukin-17 (Th17 cells). This study investigated the effects of NaCl on inflammatory arthritis in mice and humans.

MATERIALS AND METHODS

Collagen-induced arthritis (CIA) mice were fed a normal or high-salt diet ad libitum, and clinical and histologic features of arthritis were evaluated. The proportion of Th17 cells in the spleens of CIA mice fed a normal or high-salt diet was evaluated by flow cytometry, and the expression of IL-17 in joints and intestines was determined by immunohistochemical staining. We also analyzed the effect of NaCl on Th17 differentiation from peripheral blood monocytes of patients with rheumatoid arthritis (RA) and osteoarthritis (OA) and evaluated the contents of sodium and IL-17 in the synovial fluid of RA and OA patients.

RESULTS

NaCl increased murine and human Th17 cell differentiation in a dose-dependent manner. Clinical and histological arthritis was more severe in the high-salt-fed CIA mice, compared to control CIA mice. The proportion of Th17 cells among splenocytes was higher in CIA mice fed a high-salt diet. Expression of synovial and intestinal IL-17 was also higher in high-salt-fed CIA mice. Comparison of synovial fluid between RA patients and OA patients revealed that Na⁺ and IL-17 were more abundant in RA synovial fluid.

CONCLUSION

This study suggests that NaCl can aggravate arthritis by affecting Th17 differentiation. Accordingly, limiting salt intake may be helpful for treating inflammatory arthritis, such as RA.

Inhibition of spleen tyrosine kinase attenuates psoriasis-like inflammation in mice through blockade of dendritic cell-Th17 inflammation axis

Psoriasis is a debilitating autoimmune disease of the skin characterized by acanthosis and hyperkeratosis resulting from excessive growth of keratinocytes in the epidermis and inflammatory infiltrates in the dermis. Innate immune cells such as dendritic cells (DCs), perform a critical role in the pathophysiology of psoriasis by presenting inflammatory/costimulatory signals for differentiation of Th17 cells. Recent studies point to the involvement of spleen tyrosine kinase (SYK) in inflammatory signaling cascade of DCs. However, it is yet to be determined whether SYK inhibition in DCs would lead to diminishment of psoriatic inflammation. Therefore, our study evaluated the effects of SYK inhibitor, R406 on imiquimod (IMQ)-induced psoriasis-like inflammation, expression of costimulatory/inflammatory molecules in DCs and their relationship with Th17/Treg cells. Our data show that R406 causes attenuation of IMQ-induced dermal inflammation as shown by reduction in ear/back skin thickness, acanthosis and myeloperoxidase activity. This was concurrent with reduction in inflammatory cytokines and co-stimulatory molecules in CD11c + DCs such as IL-6, IL-23, MHCII, and CD40. This favoured the suppression of Th17 cells and upregulation of Treg cells in R406-treated mice with psoriasis-like inflammation. Direct activation of TLR7 by IMQ in splenocytic cultures led to increased SYK expression in CD11c + DCs and release of IL-23/IL-6. IMQ-induced IL-6/IL-23 levels were significantly diminished by SYK inhibitor, R406 in splenocytic cultures. In essence, our study shows that SYK inhibition supresses psoriasis-like inflammation by modifying DC function in mice. Further, it implies that SYK inhibition could be a prospective therapeutic approach for the treatment of psoriasis-like inflammation.

Polycyclic aromatic hydrocarbons (PAHs) present in ambient urban dust drive proinflammatory T cell and dendritic cell responses via the aryl hydrocarbon receptor (AHR) in vitro

Atmospheric particulate matter (PM) is a complex component of air pollution that is a composed of inorganic and organic constituents. The chemically-extracted organic fraction (OF) of PM excludes inorganics but retains most organic constituents like polycyclic aromatic hydrocarbons (PAHs). PAHs are ubiquitous environmental toxicants and known aryl hydrocarbon receptor (AHR) ligands. The AHR is a ligand activated transcription factor that responds to endogenous ligands and exogenous ligands including PAHs. Activation of the AHR leads to upregulation of cytochrome P450 (CYP) metabolizing enzymes which are important for the biotransformation of toxicants to less toxic, or in the case of PAHs, more toxic intermediates. Additionally, the AHR plays an important role in balancing regulatory and effector T cell responses. This study aimed to determine whether PAHs present in PM aggravate inflammation by driving inflammatory T cell and dendritic cell (DC) responses and their mechanism of action. This study tests the hypothesis that PAHs present in PM activate the AHR and alter the immune balance shifting from regulation to inflammation. To test this, the effects of SRM1649b OF on T cell differentiation and DC function were measured in vitro. SRM1649b OF enhanced Th17 differentiation in an AHR and CYP-dependent manner and increased the percent of IFNγ positive DCs in an AHR-dependent manner. SRM1649b PAH mixtures enhanced Th17 differentiation in an AHR-dependent but CYP-independent manner and increased the percent of IFNγ positive DCs. Cumulatively, these results suggest that PAHs present in PM are active components that contribute to immune responses in both T cells and BMDCs through the AHR and CYP metabolism. Understanding the role of AHR and CYP metabolism of PAHs in immune cells after PM exposure will shed light on new targets that will shift the immune balance from inflammation to regulation.

Proanthocyanidins: novel treatment for psoriasis that reduces oxidative stress and modulates Th17 and Treg cells

Psoriasis is a common, chronic, inflammatory skin disease that affects 2%-4% of the global population. Recent studies have shown that increased oxidative stress (OS) and T-cell abnormalities are central to the pathogenesis of this disease. The resulting reactive oxygen species (ROS) induces proliferation and differentiation of Th17/Th1/Th22 cells and inhibits the anti-inflammatory activities of regulatory T lymphocytes (Treg). Subsequent secretions of inflammatory cytokines, such as interleukin (IL)-17, IL-22, tumor necrosis factor alpha (TNF-α), and interferon-gamma (IFN-γ), and vascular endothelial growth factor (VEGF), stimulate keratinocyte proliferation and angiogenesis. Proanthocyanidins are a class of flavonoids from plants and fruits, and have various antioxidant, anti-inflammatory, and anti-angiogenic properties. Numerous reports have demonstrated therapeutic effects of proanthocyanidins for various diseases. Among clinical activities, proanthocyanidins suppress cell proliferation, prevent OS, and regulate Th17/Treg cells. Because the pathogenesis of psoriasis involves OS and T cells dysregulation, we reviewed the effects of proanthocyanidins on OS, Th17 and Treg cell activities, and keratinocyte proliferation and angiogenesis. Data from multiple previous studies warrant consideration of proanthocyanidins as a promising strategy for the treatment of psoriasis.

Cell wall mannan of Candida krusei mediates dendritic cell apoptosis and orchestrates Th17 polarization via TLR-2/MyD88-dependent pathway

Dendritic cells (DCs) abundantly express diverse receptors to recognize mannans in the outer surface of Candida cell wall, and these interactions dictate the host immune responses that determine disease outcomes. C. krusei prevalence in candidiasis worldwide has increased since this pathogen has developed multidrug resistance. However, little is known how the immune system responds to C. krusei. Particularly, the molecular mechanisms of the interplay between C. krusei mannan and DCs remain to be elucidated. We investigated how C. krusei mannan affected DC responses in comparison to C. albicans, C. tropicalis and C. glabrata mannan. Our results showed that only C. krusei mannan induced massive cytokine responses in DCs, and led to apoptosis. Although C. krusei mannan-activated DCs underwent apoptosis, they were still capable of initiating Th17 response. C. krusei mannan-mediated DC apoptosis was obligated to the TLR2 and MyD88 pathway. These pathways also controlled Th1/Th17 switching possibly by virtue of the production of the polarizing cytokines IL-12 and IL-6 by the C. krusei mannan activated-DCs. Our study suggests that TLR2 and MyD88 pathway in DCs are dominant for C. krusei mannan recognition, which differs from the previous reports showing a crucial role of C-type lectin receptors in Candida mannan sensing.

TGFβ1 signaling sustains aryl hydrocarbon receptor (AHR) expression and restrains the pathogenic potential of TH17 cells by an AHR-independent mechanism

The aryl hydrocarbon receptor (AHR) is a transcription factor activated by ligand highly expressed on TH17 cells, and AHR-deficient CD4+ T cells have impaired production of IL-17A and IL-22. Although AHR activation can exacerbate in vivo TH17 cell-mediated autoimmunity, accumulating data indicate that AHR is a nonpathogenic TH17 marker. Thus it remains unclear how AHR activation is regulated and impacts on the generation of TH17 subsets. Here we demonstrated that AHR pathway is activated during in vitro pathogenic TH17 polarization, but it is quickly downregulated. Under these conditions, additional AHR activation promoted IL-22 but not IL-17A. Interestingly, AHR high sustained expression and IL-17A promotion were only achieved when TGFβ1 was present in the culture. In addition to the effect on AHR regulation, TGFβ1 presented a dual role by simultaneously suppressing the TH17 pathogenic phenotype acquisition. This latter effect was independent of AHR stimulation, since its activation did not confer a TH17 anti-inflammatory profile and Ahr-/- cells did not upregulate any TH17 pathogenic marker. Through the use of EAE model, we demonstrated that AHR is still functional in encephalitogenic CD4+ T cells and the adoptive transfer of Ahr-/- TH17 cells to recipient mice resulted in milder EAE development when compared to their WT counterparts. Altogether, our data demonstrated that although AHR is highly expressed on in vitro-generated nonpathogenic TH17 cells, its ligation does not shift TH17 cells to an anti-inflammatory phenotype. Further studies investigating the role of AHR beyond TH17 differentiation may provide a useful understanding of the physiopathology of autoimmune diseases.

Effect of the anti-IL-17 antibody on allergic inflammation in an obesity-related asthma model

BACKGROUND/AIMS

The co-occurrence of obesity aggravates asthma symptoms. Diet-induced obesity increases helper T cell (TH) 17 cell differentiation in adipose tissue and the spleen. The 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor pravastatin can potentially be used to treat asthma in obese patients by inhibiting interleukin 17 (IL-17) expression. This study investigated the combined effects of pravastatin and anti-IL-17 antibody treatment on allergic inflammation in a mouse model of obesity-related asthma.

METHODS

High-fat diet (HFD)-induced obesity was induced in C57BL/6 mice with or without ovalbumin (OVA) sensitization and challenge. Mice were administered the anti-IL-17 antibody, pravastatin, or both, and pathophysiological and immunological responses were analyzed.

RESULTS

HFD exacerbated allergic airway inflammation in the bronchoalveolar lavage fluid of HFD-OVA mice as compared to OVA mice. Blockading of the IL-17 in the HFD-OVA mice decreased airway hyper-responsiveness (AHR) and airway inflammation compared to the HFD-OVA mice. Moreover, the administration of the anti-IL-17 antibody decreased the leptin/adiponectin ratio in the HFD-OVA but not the OVA mice. Co-administration of pravastatin and anti-IL-17 inhibited airway inflammation and AHR, decreased goblet cell numbers, and increased adipokine levels in obese asthmatic mice.

CONCLUSION

These results suggest that the IL-17-leptin/adiponectin axis plays a key role in airway inflammation in obesity-related asthma. Our findings suggest a potential new treatment for IL-17 as a target that may benefit obesity-related asthma patients who respond poorly to typical asthma medications.

Glutathione de novo synthesis but not recycling process coordinates with glutamine catabolism to control redox homeostasis and directs murine T cell differentiation

Upon antigen stimulation, T lymphocytes undergo dramatic changes in metabolism to fulfill the bioenergetic, biosynthetic and redox demands of proliferation and differentiation. Glutathione (GSH) plays an essential role in controlling redox balance and cell fate. While GSH can be recycled from Glutathione disulfide (GSSG), the inhibition of this recycling pathway does not impact GSH content and murine T cell fate. By contrast, the inhibition of the de novo synthesis of GSH, by deleting either the catalytic (Gclc) or the modifier (Gclm) subunit of glutamate-cysteine ligase (Gcl), dampens intracellular GSH, increases ROS, and impact T cell differentiation. Moreover, the inhibition of GSH de novo synthesis dampened the pathological progression of experimental autoimmune encephalomyelitis (EAE). We further reveal that glutamine provides essential precursors for GSH biosynthesis. Our findings suggest that glutamine catabolism fuels de novo synthesis of GSH and directs the lineage choice in T cells.

Ambient particulate matter enhances the pulmonary allergic immune response to house dust mite in a BALB/c mouse model by augmenting Th2- and Th17-immune responses

Ambient particulate matter (PM) exacerbates airway inflammation and hyper-reactivity in asthmatic patients. Studies show that PM has adjuvant-like properties that enhance the allergic inflammatory response; however, the mechanisms through which PM enhances these processes remain elusive. The objective of the study was to examine how ambient PM enhances the allergic immune response. Eight-week-old BALB/c mice were sensitized with house dust mite (HDM) or HDM and ambient particulate matter (PM, 2.5 μm; Sacramento, CA) to assess how PM modulates the development of adaptive immune responses against allergens. Both groups were challenged with HDM only. Bronchoalveolar lavage (BAL) was analyzed for extent of airway inflammation. Lung tissue was used for histological analysis, mucosubstance quantification, and heme oxygenase-1 (HO-1) localization/quantification. Gene expression was analyzed in whole lung to characterize immune markers of inflammation: cytokines, chemokines, antioxidant enzymes, and transcription factors. Cytokine and chemokine protein levels were quantified in whole lung to confirm gene expression patterns. Compared to HDM-only sensitization, exposure to PM during HDM sensitization led to significant immune cell recruitment into the airway subepithelium, IgE gene expression, mucosubstance production, and Th2-associated cytokine expression. HO-1 levels were not significantly different between the treatment groups. Gene expression profiles suggest that polycyclic aromatic hydrocarbon (PAH) content in PM activated the aryl hydrocarbon receptor (AhR) and enhanced Th17-responses in the mice that received HDM and PM compared to mice that received HDM-only. The findings suggest that PM enhances allergic sensitization via enhancement of Th2-mediated inflammation and that AhR activation by PAHs in PM promotes Th17-immune responses.

Artemisinin ameliorates the symptoms of experimental autoimmune myasthenia gravis by regulating the balance of TH1 cells, TH17 cells and Treg cells

Myasthenia gravis (MG) is an autoimmune disease characterized by fatigue and muscle weakness. Artemisinin and its derivatives were reported to be experimentally used to treat autoimmune diseases, such as systemic lupus erythematosus (SLE) and experimental allergic encephalomyelitis (EAE). Here, we tested the effects of artemisinin on experimental autoimmune myasthenia gravis (EAMG). Our data confirmed that artemisinin markedly ameliorated the symptoms of EAMG rats. There was a decreased level of tumor necrosis factor-α (TNF-α) and IL-17+ cells in mononuclear cells (MNCs), and an increased level of transforming growth factor-β1 (TGF-β1) and Treg cells in MNCs. These findings indicate that artemisinin may be a new choice for MG treatment.

Dang-Gui-Liu-Huang Tang a traditional herbal formula, ameliorates imiquimod-induced psoriasis-like skin inflammation in mice by inhibiting IL-22 production

BACKGROUND

The traditional herbal formula, Dang-Gui-Liu-Huang Tang (DGLHT) has been previously shown to inhibit T lymphocyte proliferation and suppress dendritic cell function. Hypothesis/Purpose: To assess the therapeutic value of DGLHT for the treatment of psoriasis, a Th1 and/or Th17 cell-mediated inflammatory skin disease, and to investigate the underlying molecular mechanisms.

METHODS

An in vivo mouse model of imiquimod (IMQ)-induced psoriasis-like inflammation was used to investigate the effect of DGLHT. The anti-inflammatory effects of an ethanolic extract of DGLHT (DGLHT-E) and the mechanism responsible were examined in an in vitro model using IL-1α, IL-17A, IL-22, oncostatin M, plus TNF-α (M5) stimulated HaCaT cells. The anti-proliferative effect of DGLHT-E was examined by analyzing the expression levels of K16, K17 and Ki67 in IL-22 stimulated HaCaT cells.

RESULTS

Topical application of 1% DGLHT-E significantly reduced psoriasis-like symptoms including scaling and epidermal hyperplasia in IMQ-treated mice. Immunohistochemical studies showed that DGLHT-E exerted potent anti-inflammatory effects by inhibiting IL-22 production in local skin lesions. DGLHT-E also attenuated the productions of CXCL10 and CCL20 in M5-stimulated HaCaT cells by suppressing the ERK1/2, JNK and STAT3 signaling pathways. Furthermore, berberine hydrochloride, a primary constituent of DGLHT-E inhibited the expressions of the proliferation markers K16 and K17 in IL-22 stimulated HaCaT cells.

CONCLUSION

These results suggested that DGLHT-E offers a possible treatment for psoriasis, and that berberine hydrochloride might be a useful component of ointment-based treatments for psoriatic lesions.

SOST Gene Inhibits Osteogenesis from Adipose-Derived Mesenchymal Stem Cells by Inducing Th17 Cell Differentiation

BACKGROUND/AIMS

Postmenopausal osteoporosis is considered to be an autoimmune and inflammatory process, and IL-17 plays important roles in the loss of bone mass. Sclerostin (SOST) acts as a negative regulator of bone formation by inhibiting the Wnt signaling pathway. It also is a mediator of the crosstalk between the skeletal and immune systems. However, few studies have examined the role of SOST gene in the differentiation of T helper 17 (Th17) cells.

METHODS

Adipose-derived stem cells (ADSCs) were isolated and transfected with pcDNA3-SOST or shSOST, and then co-cultured with CD4+ T cells isolated from peripheral blood mononuclear cells. The differentiation, adipogenesis, and osteogenesis of Th17 and regulatory T (Treg) cells were examined by western blot, intracellular and intranuclear staining, ELISA, and real-time quantitative PCR in this co-culture model.

RESULTS

The SOST gene promoted the secretion of IL-6 and TGF-β in ADSCs. After co-culture of ADSCs with CD4+ T cells, the SOST gene increased the number of CD4+IL-17+ cells and the levels of IL-17 and RORγ. However, the number of CD4+CD25+Foxp3+ cells was decreased, which was accompanied with a reduction of IL-10 and Foxp3 expression. In the meantime, the SOST gene inhibited the expression of COL1, OCN, and OPN, reduced the activity of alkaline phosphatase, and increased the expression of LPL and PPARγ. Furthermore, IL-17 promoted SOST gene-induced adipogenesis and increased the inhibition of osteogenesis.

CONCLUSIONS

SOST promoted the differentiation of Th17 cells and reduced the differentiation of Treg cells, which exacerbated the SOST gene-induced inhibition of osteogenesis from ADSCs.

Curcumin for the Management of Periodontitis and Early ACPA-Positive Rheumatoid Arthritis: Killing Two Birds with One Stone

We propose curcumin as a preventive measure to avoid/manage periodontitis (PD), and as a natural immunosuppressant for rheumatoid arthritis (RA). PD, mainly caused by Porphyromonas gingivalis forming biofilm and leading to tooth decay, is a major public health issue and a risk factor for the development of RA in humans. P. gingivalis is able to trigger experimental autoimmune arthritis in animal models and in humans can induce citrullinated peptides, which not only are a source of anti-citrullinated antibodies (ACPAs), but also participate in autoreactive responses and disease development. Curcumin appears to have efficient anti-bacterial activity against P. gingivalis infection and biofilm formation. In addition to antibacterial, anti-oxidant, and anti-inflammatory action, curcumin exerts unique immunosuppressant properties via the inhibition of Th17 pro-inflammatory responses and promotion of regulatory T cells, thus suppressing autoimmunity. We introduce curcumin as a natural product for the management of both PD and RA-related autoreactivity, possibly also as a preventive measure in early RA or individuals at high risk to develop RA.

Anti-TNF Therapy Induces CD4+ T-Cell Production of IL-22 and Promotes Epithelial Repairs in Patients With Crohn's Disease

Background

Anti-tumor necrosis factor (TNF) therapy appears to be effective in the treatment of Crohn's disease (CD), a chronic inflammatory disease of the gastrointestinal tract. However, the mechanisms involved are not completely understood.

Methods

Fifty-seven active CD patients were enrolled, and cytokine profiles in colonic biopsies of patients with active CD receiving anti-TNF monoclonal antibody (mAb) (infliximab [IFX]) treatment were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Colonic biopsies of active CD patients and healthy donors were cultured with IFX in vitro, and cytokine profiles were measured by qRT-PCR. Peripheral blood (PB)-CD4+ T cells were stimulated with anti-CD3 and anti-CD28 mAbs in the presence of human immunoglobin (HIg), IFX, recombinant human TNF-α converting enzyme (rhTACE), and aryl hydrocarbon receptor (AhR) inhibitor (CH-223191), respectively, to determine interleukin (IL)-22 expression by CD4+ T cells. Caco2 cells were also utilized to study their potential role in modulating epithelial cell barrier repairs in vitro.

Results

IFX therapy markedly upregulated IL-22 mRNA expression in the gut mucosa of CD patients. In vitro treatment with IFX greatly promoted CD CD4+ T cells to express IL-22, which was inhibited by rhTACE, indicating that reverse signaling through binding to membrane-bound TNF mediates anti-TNF-induced IL-22 expression of CD CD4+ T cells. However, blockade of AhR markedly inhibited anti-TNF-induced IL-22+CD4+ T (Th22) cell differentiation in CD patients. Moreover, treatment with IL-22 induced intestinal epithelial cell expression of tight junction proteins (eg, claudin1 and ZO-1) and facilitated transepithelial resistance, indicating that IL-22 protects intestinal mucosa from inflammation via maintenance of epithelial barrier integrity.

Conclusions

Our results uncover a novel mechanism whereby anti-TNF therapy upregulates IL-22 production in CD patients through promoting Th22 cell differentiation and contributes to intestinal epithelial barrier repairs.

Effects of Astragalus glycoprotein on Th17/Treg cells in mice with collagen-induced arthritis

In this study of Th17/Treg cells, the therapeutic effect of Astragalus glycoprotein on collagen-induced arthritis in mice (CIA) was explored, and a basis for the clinical treatment of rheumatoid arthritis is provided. Sixty mice were selected for the establishment of a CIA mouse model, and were then randomly divided into a CIA model group, a hydrocortisone control group, a low, medium, and high dose group of Astragalus glycoprotein, respectively. The same number of control groups with same number of mice was established and after basic immunization, intraperitoneal injections were given once daily for two weeks in the treatment. At the end of the treatment, the mice in each group were selected and the proportion of Th17/Treg cells was detected by flow cytometry. The expression and positive expression of RORt, Foxp3, P-STAT3 and P-STAT5 protein were detected by Western blot and immunohistochemistry. Astragalus glycoprotein was shown to potentially improve the diet and mental state, reduce the arthritis index score and improve the pathological state of synovial membranes in the mice. Moreover, flow cytometry results showed that, compared with the CIA model group, the proportion of Th17 cells in the four other groups of mice decreased, while the proportion of Treg cells increased. This difference was statistically significant (P less than 0.05). From the experiment, the following conclusions were drawn: Astragalus glycoprotein can reduce Th17 cells and their transcription factors in the peripheral blood of CIA mice, up-regulate Treg cells and their transcription factors, and correct the balance of Th17/Treg cells so as to achieve an effective of treatment for CIA mice.

CCDC134 ameliorated experimental autoimmune encephalomyelitis by suppressing Th1 and Th17 cells

CCDC134 (coiled-coil domain containing 134), a cytokine-like molecule, was previously reported to exert antitumor effects by augmenting CD8⁺ T-cell mediated immunity. However, the dynamic changes in CCDC134 expression patterns in the spinal cord that may be involved in the progression of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, remains unclear. In this study, we found that CCDC134 expression was markedly increased in the spinal cord during the progression of EAE. Furthermore, we demonstrated that CCDC134 significantly reduced the severity and slowed the progression of EAE, which correlated with reduced spinal cord inflammation and demyelination. The underlying mechanism of CCDC134-induced effects involved inhibition of T helper (Th)-1 and Th17 cell differentiation and secretion of its key effector molecules IFN-γ and IL-17A via regulation of JAK/STAT signaling. These findings indicate that CCDC134 exerts potent anti-inflammatory effects through the selective modulation of pathogenic Th1 and Th17 cells by targeting critical signaling pathways. The study provides insights into the role of CCDC134 as a unique therapeutic agent for the treatment of autoimmune diseases.

Amelioration of Experimental autoimmune encephalomyelitis and DSS induced colitis by NTG-A-009 through the inhibition of Th1 and Th17 cells differentiation

CD4+ T cells are the central for the mammalian adaptive immune system. Naïve CD4+ T cells mainly differentiate in to pro-inflammatory Th1, Th2 and Th17 cells upon antigenic stimulation. IFN-γ secreting Th1 cells and IL-17 secreting Th17 cells are found to play key roles in autoimmune diseases like multiple sclerosis (MS) and ulcerative colitis (UC). In this study we found NTG-A-009, 6-aminopyridin-3-ol, has great inhibitory effect on in vitro differentiation of Th1 and Th17 cells without affecting regulatory T cells. Moreover, NTG-A-009 had no effect on CD4+ T cell proliferation and viability. In vivo treatment has shown that NTG-A-009 has ameliorated experimental autoimmune encephalomyelitis (EAE) and dextran sulfate sodium (DSS) induced colitis through the inhibition of Th1 and Th17 cells differentiation. Mechanistically, NTG-A-009 suppressed Th1 and Th17 cells differentiation via the modulation of JAK/STAT signaling pathway. Thus, our data demonstrated that NTG-A-009 ameliorated inflammation through the inhibition of Th1 and Th17 cells generation making it a potential therapeutic candidate for the treatment of inflammatory diseases.