Arsenic trioxide improves Treg and Th17 balance by modulating STAT3 in treatment-naïve rheumatoid arthritis patients.

We aimed to investigate the immunologic mechanisms by which arsenic trioxide (As2O3) may inhibit T helper 17 (Th17) cell differentiation while promoting regulatory T (Treg) cell generation by modulating signal transducer and activator of transcription 3 (STAT3) in treatment-naïve rheumatoid arthritis (RA) patients. Naïve CD4+T cells isolated by fluorescence-activated cell sorting from treatment-naïve RA patients and healthy controls were used to investigate the effect of As2O3 on the process of polarization and the related cytokines. STAT3 transfection experiments were conducted with small interfering RNA (siRNA) and lentivirus STAT3 to verify the mechanism of As2O3 on Th17-Treg balance in vitro. A collagen-induced arthritis (CIA) model was used to detect the clinical scores, histopathological change, bone destruction, Th17-Treg proportion and joint tissue immunohistochemistry. We found that As2O3 prevented activated naïve CD4+T-cells from differentiating into Th17 cells and reduced cytokine production by activated Th17 cells by downregulating their signature transcription factors, STAT3 and orphan nuclear receptors. Notably, As2O3 reduced Th17 cells frequency while increasing Treg cells frequency under specific polarizing conditions in treatment-naïve RA patients by transfecting siRNA STAT3 and lentivirus STAT3. Furthermore, we noticed that applying As2O3 in the CIA model attenuated the infiltration of joint inflammation and bone destruction, and significantly improved the imbalanced Treg-Th17 ratio. These data indicate that As2O3 may be a potential immune modulator for treatment-naïve RA patients that helps to balance of Treg and Th17 cells through modulating STAT3.

Li C ，Zhang J ，Wang W ，Wang H ，Zhang Y ，Zhang Z ... -  《-》

Maresin 1 improves the Treg/Th17 imbalance in rheumatoid arthritis through miR-21.

Jin S ，Chen H ，Li Y ，Zhong H ，Sun W ，Wang J ，Zhang T ，Ma J ，Yan S ，Zhang J ，Tian Q ，Yang X ，Wang J ... -  《-》

Tetrandrine ameliorates collagen-induced arthritis in mice by restoring the balance between Th17 and Treg cells via the aryl hydrocarbon receptor.

Tetrandrine is an alkaloid constituent of the root of Stephania tetrandra S. Moore. The long-term clinical uses of tetrandrine for treatments of rheumatalgia and arthralgia as well as the inhibition of rat adjuvant-induced arthritis imply that tetrandrine may have therapeutic potential in rheumatoid arthritis (RA). Here, we explored its anti-RA mechanism in collagen-induced arthritis (CIA) in relation to the balance between T helper (Th) 17 cells and regulatory T (Treg) cells. DBA/1 mice were immunized with chicken type II collagen and were orally administered tetrandrine for 14 consecutive days. Then, the mice were sacrificed, their joints were removed for histological analysis, and spleens and mesenteric lymph nodes (MLNs) were removed to examine the Th17 and Treg cells. Tetrandrine markedly alleviated the severity of arthritis, reduced the serum levels of pro-inflammatory cytokines, and restored the Th17/Treg balance, as demonstrated by the serum levels of their related cytokines (IL-17 and IL-10) and the proportion of each cell type. Tetrandrine inhibited Th17 cell differentiation and induced Treg cell differentiation in vitro . Notably, aryl hydrocarbon receptor (AhR) was proven to play a crucial role in tetrandrine-mediated T cell differentiation. The correlation between AhR activation, regulation of Th17/Treg and amelioration of arthritis by tetrandrine was verified in the CIA mice. Moreover, tetrandrine might be a ligand of AhR because it facilitated the expression of the AhR target gene cytochrome P450 1A1 (CYP1A1) and the activation of its downstream signaling pathways. Taken together, tetrandrine exerts its anti-arthritis efficacy by restoring Th17/Treg balance via AhR.

Yuan X ，Tong B ，Dou Y ，Wu X ，Wei Z ，Dai Y ... -  《-》

Wutou decoction alleviates arthritis inflammation in CIA mice by regulating Treg cell stability and Treg/Th17 balance via the JAK2/STAT3 pathway.

Wutou Decoction (WTD) is a classic traditional Chinese medicine formula, which has shown clinical efficacy in treating rheumatoid arthritis (RA). The Treg stability and Th17/Treg imbalance is an important immunological mechanism in RA progression. Whether WTD regulates CD4+ T cell subsets has not been thoroughly investigated yet. This study aimed to explore the potential role and mechanisms of WTD in regulating the diminished stability of Treg cells and the imbalance of CD4+ T cell subsets via in vivo and in vitro experiments. Firstly, the therapeutic effects of WTD on the collagen-induced arthritis (CIA) mouse and its potential regulatory function on CD4+ T cell subsets were evaluated in vivo. Animal specimens were collected after 31 days of treatment with WTD. The anti-arthritic and anti-inflammatory effects of WTD were assessed through arthritis scoring, body weight, spleen index, serum IL-6 levels, and micro-PET/CT imaging. Gene enrichment analysis was performed to evaluate the activation T cell-related signaling pathway. Flow cytometry was used to determine the proportions of CD4+ T cell subsets in vitro and in vitro. Additionally, ELISA was used to assess the secretion of IL-10 and TGF-β by Treg cells under inflammatory conditions. The suppressive function of Treg cells on cell proliferation under inflammatory conditions was examined using CFSE labeling. Immunofluorescence staining was performed to detect the phosphorylation levels of STAT3 in CD4+ T cells from mouse spleen tissues. Western blotting was used to evaluate the phosphorylation levels of JAK2/STAT3 in Treg cells. WTD significantly alleviated joint inflammation in CIA mice. WTD reduced serum IL-6 levels in CIA mice, improved their body weight and spleen index. WTD treatment inhibited the activation of CD4+ T cell subgroup-related signaling in the joint tissues of CIA mice. In vitro and in vitro experiments showed that WTD increased the proportion of Treg cells and decreased the proportion of Th17 cells in CIA mice spleen. Furthermore, WTD promoted the secretion of IL-10 and TGF-β by Treg cells and enhanced the inhibitory capacity of Treg cells on cell proliferation under inflammatory conditions. Immunofluorescence detected decreased STAT3 phosphorylation levels in CD4+ T cells from CIA mice spleen, while western blotting revealed a decrease in JAK2/STAT3 phosphorylation levels in Treg cells in vitro. Inhibiting JAK2/STAT3 phosphorylation is a potential mechanism through which WTD improves Treg cell stability, balances CD4+ T cell subsets, and attenuates RA joint inflammation.

Han L ，Yan J ，Li T ，Shen P ，Ba X ，Lin W ，Zhang R ，Yang Y ，Li Y ，Li C ，Huang Y ，Qin K ，Liu Y ，Huang H ，Zou L ，Wang Y ，Chen Z ，Huang Y ，Tu S ... -  《-》

Data on arsenic trioxide modulates Treg/Th17/Th1/Th2 cells in treatment-naïve rheumatoid arthritis patients and collagen-induced arthritis model mice.

In this article, we share the raw protein and mRNA data obtained from basal and stimulated human peripheral blood mononuclear cells (PBMCs) derived from 15 individual treatment-naïve rheumatoid arthritis (RA) patients and synovial fluid mononuclear cells (SFMCs). In treatment-naïve RA patients, PBMCs were treated with a gradient of concentrations of As2O3 (0, 0.1, 0.5, 1.0, 2.0, 4.0 μM) for 48 hours. We found that 2.0 μM As2O3 promoted the apoptosis of PBMCs significantly, and 0.5 μM As2O3 was the lowest and effective concentration that contributed to Treg cell generation but it prevented Th17 cell differentiation, as assessed by flow cytometry. Furthermore, As2O3 decreased the transcription factor STAT3 mRNA expression of Th17 cells but increased the transcription factor Foxp3 of Treg cells. In synovial fluid from RA patients, consistent with PBMCs, As2O3 inhibited Th17 cell differentiation but promoted Treg cell generation. In an animal experiment, we analyzed the body-weight of mice as the indicator of As2O3 toxicity and calculated the spleen index. As2O3 significantly decreased the hematoxylin and eosin score in Type II collagen-induced arthritis in mice. Furthermore, As2O3 downregulated the frequency of Th1 but upregulated Th2 cells. For more insight please see Arsenic trioxide improves Treg and Th17 balance by modulating STAT3 in treatment-naive rheumatoid arthritis patients [1].

Li C ，Zhang J ，Wang W ，Wang H ，Zhang Y ，Zhang Z ... -  《-》