Long non-coding RNA MEG3 inhibits M2 macrophage polarization by activating TRAF6 via microRNA-223 down-regulation in viral myocarditis.

Viral myocarditis (VMC) commonly triggers heart failure, for which no specific treatments are available. This study aims to explore the specific role of long non-coding RNA (lncRNA) maternally expressed 3 (MEG3) in VMC. A VMC mouse model was induced by Coxsackievirus B3 (CVB3). Then, MEG3 and TNF receptor-associated factor 6 (TRAF6) were silenced and microRNA-223 (miR-223) was over-expressed in the VMC mice, followed by determination of ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS). Dual-luciferase reporter assay was introduced to test the interaction among MEG3, TRAF6 and miR-223. Macrophages were isolated from cardiac tissues and bone marrow, and polarization of M1 or M2 macrophages was induced. Then, the expressions of components of NLRP3 inflammatory body (NLRP3, ASC, Caspase-1), M1 markers (CD86, iNOS and TNF-α) and M2 markers (CD206, Arginase-1 and Fizz-1) were measured following MEG3 silencing. In the VMC mouse model, MEG3 and TRAF6 levels were obviously increased, while miR-223 expression was significantly reduced. Down-regulation of MEG3 resulted in the inhibition of TRAF6 by promoting miR-223. TRAF6 was negatively correlated with miR-223, but positively correlated with MEG3 expression. Down-regulations of MEG3 or TRAF6 or up-regulation of miR-223 was observed to increase mouse weight, survival rate, LVEF and LVFS, while inhibiting myocarditis and inflammation via the NF-κB pathway inactivation in VMC mice. Down-regulation of MEG3 decreased M1 macrophage polarization and elevated M2 macrophage polarization by up-regulating miR-223. Collectively, down-regulation of MEG3 leads to the inhibition of inflammation and induces M2 macrophage polarization via miR-223/TRAF6/NF-κB axis, thus alleviating VMC.

The numbers of peripheral regulatory T cells are reduced in patients with psoriatic arthritis and are restored by low-dose interleukin-2.

BACKGROUND: Although regulatory T cells (Tregs) play crucial roles in the maintenance of immune hemostasis, the numbers of peripheral Tregs in patients with psoriatic arthritis (PsA) remain unclear. We measured these numbers and the efficacy and safety of low-dose interleukin-2 (IL-2) therapy. METHODS: We recruited 95 PsA patients, of whom 22 received subcutaneous low-dose IL-2 [0.5 million international units (MIU) per day for 5 days] combined with conventional therapies. The absolute numbers of cells in peripheral CD4+ T cell subsets were measured via modified flow cytometry. Clinical and laboratory indicators were compared before and after treatment. RESULTS: PsA patients had lower peripheral Treg numbers than healthy controls (p < 0.01), correlating significantly and negatively with the levels of disease indicators (p < 0.05). Although low-dose IL-2 significantly increased the Th17 and Treg numbers in PsA patients compared with the baseline values, the Treg numbers rose much more rapidly than those of Th17 cells, re-balancing the Th17 and Treg proportions. Low-dose IL-2 combination therapy rapidly reduced PsA disease activities as indicated by the DAS28 instrument, thus the number of tender joints, visual analog scale pain, physician global assessment, the dermatology life quality index score, and the health assessment questionnaire score (all p < 0.05). CONCLUSION: PsA patients exhibited low Treg numbers. Low-dose IL-2 combination treatment increased these numbers and relieved disease activity without any apparent side effects. Additional studies are required to explore the long-term immunoregulatory utility of IL-2 treatment.

Silencing of STAT4 Protects Against Autoimmune Myocarditis by Regulating Th1/Th2 Immune Response via Inactivation of the NF-κB Pathway in Rats.

Signal transducer and activator of transcription 4 (STAT4) has been implicated in the progression of myocarditis. The aim of the current study was to investigate the role by which STAT4 influences autoimmune myocarditis in an attempt to identify a theoretical therapeutic perspective for the condition. After successful establishment of an autoimmune myocarditis rat model, the expression patterns of STAT4, NF-κB pathway-related genes, Th1 inflammatory cytokines (IFN-γ and IL-2), and Th2 inflammatory cytokines (IL-6 and IL-10) were subsequently determined. The rats with autoimmune myocarditis were treated with oe-STAT4 or sh-STAT4 lentiviral vectors to evaluate the role of STAT4 in autoimmune myocarditis, or administrated with 1 mL 10 µmol/L of BAY11-7082 (the NF-κB pathway inhibitor) via tail vein to investigate the effect of the NF-κB pathway on autoimmune myocarditis. Finally, cell apoptosis was evaluated. The serum levels of IFN-γ and IL-2, extent of IκBα and P65 phosphorylation, and the expression of STAT4 were elevated, while the serum levels of IL-6 and IL-10 as well as the expression of IκBα were reduced among the rats with autoimmune myocarditis, which was accompanied by an increase in the apoptotic cells. More importantly, the silencing of STAT4 or the inhibition of the NF-κB pathway was detected to result in a decrease in the serum levels of IFN-γ and IL-2 and an elevation of the serum levels of IL-6 and IL-10, and inhibited myocardial cell apoptosis in rats with autoimmune myocarditis. Moreover, STAT4 silencing was also observed to decrease the extent of IκBα and P65 phosphorylation while acting to elevate the expression of IκBα. Taken together, silencing of STAT4 could hinder the progression of autoimmune myocarditis by balancing the expression of Th1/Th2 inflammatory cytokines via the NF-κB pathway, which may provide a novel target for experimental autoimmune myocarditis (EAM) treatment.