[Efficacy and safety of metformin for Behcet's disease and its effect on Treg/Th17 balance: a single-blinded, before-after study]

Regulatory Role of circRNA-0067835 in Behcet Disease through Targeting Micro RNA-155: Implication of ATG1, AKT and MTOR

Background

Autophagy has been proven to contribute to maintaining eukaryotic cells' normal intracellular homeostasis, whereas autophagy malfunction may predispose to Behcet Disease (BD). The accumulation of the products of autophagic degradation as well as impairment in autophagic flux in cases with BD, may be attributed to dysregulated miRNA-155 expression. This study attempts to determine the contribution of circRNA-0067835 in miRNA-155-mediated modulation of the autophagy axis as well as to investigate its impact on the production of pro-inflammatory cytokines in BD.

Methods

This study was carried out on 40 cases with BD and 40 healthy control subjects. The collection of serum samples was done before performing a real-time PCR to estimate the relative gene expression of ATG1, AKT, miRNA-155, mTOR, TAB2, and circRNA-0067835. Additionally, IL-1β, IL-17, and TNF-α serum levels were determined by ELISA.

Results

Behcet Disease (BD) patients had significantly upregulated circRNA-0067835, with subsequent downregulation of its target gene, miRNA-155 than controls (P<0.05). In addition, decreased miRNA-155 gene expression was correlated with significantly increased TAB2 gene expression levels in BD patients compared to the controls (P<0.05). Furthermore, enhanced production of pro-inflammatory cytokines was detected in cases with BD than in controls.

Conclusion

The correlation between circRNA-0067835 and miRNA-155 fairly contributes to the regulation of cytokine production in BD via the modulation of autophagy. The investigation of the circRNA-0067835 and the microRNA-155 and their downstream adaptor molecules could be a potential therapeutic agent for BD.

Regulatory T Cells: Therapeutic Opportunities in Uveitis

Regulatory T cells (Tregs) are critical for the maintenance of immune tolerance and the suppression of excessive inflammation. Many inflammatory autoimmune disorders, including autoimmune uveitis, involve the loss of the suppressive capacities of Tregs. Over the past decade, Tregs' therapeutic potential in uveitis has garnered increasing attention. Specific subsets of Tregs, including TIGIT+ and PD-1+ Tregs, have emerged as potent immunosuppressors that may be particularly well-suited to cell-based therapeutics. Studies have elucidated the interaction between Treg development and the gut microbiome as well as various intracellular signaling pathways. Numerous cell-based therapies and therapeutic molecules have been proposed and investigated using the murine experimental autoimmune uveitis (EAU) model. However, certain challenges remain to be addressed. Studies involving the use of Tregs in human patients with uveitis are lacking, and there are concerns regarding Tregs' production and purification for practical use, their plasticity towards inflammatory phenotypes, immunogenicity, and tumorigenicity. Nevertheless, recent research has brought Tregs closer to yielding viable treatment options for uveitis.

The Th17 Pathway in Vascular Inflammation: Culprit or Consort?

The involvement of IL-17A in autoimmune and inflammatory diseases has prompted the development of therapeutic strategies to block the Th17 pathway. Promising results came from their use in psoriasis and in ankylosing spondylitis. IL-17A acts on various cell types and has both local and systemic effects. Considering the premature mortality observed during chronic inflammatory diseases, IL-17A action on vascular cells was studied. Both in vitro and in vivo results suggest that this cytokine favors inflammation, coagulation and thrombosis and promotes the occurrence of cardiovascular events. These observations led to study the role of IL-17A in diseases characterized by vascular inflammation, namely allograft rejection and vasculitis. Increased circulating levels of IL-17A and histological staining reveal that the Th17 pathway is involved in the pathogenesis of these diseases. Vasculitis treatment faces challenges while the use of steroids has many side effects. Regarding results obtained in giant cell arteritis with IL-6 inhibitors, a cytokine involved in Th17 differentiation, the use of anti-IL-17 is a promising strategy. However, lessons from rheumatoid arthritis and multiple sclerosis must be learnt before targeting IL-17 in vasculitis, which may be culprit, consort or both of them.