Cilostazol on the expression of ICAM-1, VCAM-1 and inflammatory factors in plasma in patients with thromboangiitis obliterans

Thromboangiitis obliterans plasma-derived exosomal miR-223-5p inhibits cell viability and promotes cell apoptosis of human vascular smooth muscle cells by targeting VCAM1

Background: Exosomes-encapsulated microRNAs (miRNAs) have been established to be implicated in the pathogenesis of different diseases. Nevertheless, circulating exosomal miRNAs of thromboangiitis obliterans (TAO) remains poorly understood. This study aimed to explore the effects of exosomal miRNAs associated with TAO on human vascular smooth muscle cells (HVSMCs).Methods: The exosomes were isolated from the plasma of TAO patients and normal controls and then were sent for small RNA sequencing. Differentially expressed miRNAs (DE-miRNAs) were identified by bioinformatics analysis and were confirmed by RT-qPCR. After that, PKH67 staining was used to label exosomes and co-cultured with HVSMCs. Cell viability and apoptosis were, respectively, tested by CCK-8 assay and flow cytometry. Finally, dual-luciferase reporter assay was used to confirm the downstream targets of miR-223-5p.Results: A total of 39 DE-miRNAs were identified between TAO patients and normal controls, of which, miR-223-5p was one of the most significantly up-regulated miRNAs. TAO plasma-derived exosomes or miR-223-5p mimics inhibited cell viability of HVSMCs and promoted cell apoptosis. The pro-apoptotic effect of TAO plasma-derived exosomes was alleviated by miR-223-5p inhibitor. Additionally, the expressions of VCAM1 and IGF1R were down-regulated by exosomes and miR-223-5p mimics, and were abrogated by miR-223-5p inhibitor. Dual-luciferase report showed that VCAM1 was the target of miR-223-5p.Conclusions: Our findings imply that circulating exosomal miR-223-5p may play an essential role in the pathogenesis of TAO, and provide a basis for miR-6515-5p/VCAM1 as novel therapeutic targets and pathways for TAO treatment.

Risk Factors, Mechanisms and Treatments of Thromboangiitis Obliterans: An Overview of Recent Research

BACKGROUND

Thromboangiitis obliterans (TAO) is a nonatherosclerotic thromboticocclusive vasculitis that affects the vessels of the small and medium-sized extremities. No explicit etiology or pathogenesis of TAO has been proven, and more effective treatments are needed.

OBJECTIVE

The study aimed to summarize and present an overview of recent advances regarding the risk factors, mechanisms and treatments of TAO and to organize the related information in figures to provide a comparatively complete reference.

METHODS

We searched PubMed for English-language literature about TAO without article type limits, including articles about the risk factors, pathological mechanisms and treatments of TAO in the last 10 years with essential supplements (references over ranges and English abstracts of Russian literature).

RESULTS

After screening content of works of literature, 99 references were evaluated. We found that risk factors of TAO include smoking, gene factors and periodontal diseases. The underlying mechanism of TAO involves oxidative stress, immunity, hemodynamic changes, inflammation and so on. Moreover, similarities in genetic factors and cigarette relevance existed between periodontal diseases and TAO, so further study of relationship was required. For TAO treatment, medicine, endovascular intervention and revascularization surgery, autologous cell therapy and novel therapies were also mentioned. Besides, a hypothesis that infection triggers autoimmunity in TAO could be speculated, in which TLR4 plays a key role.

CONCLUSION

1. A hypothesis is put forward that infections can trigger autoimmunity in TAO development, in which TLR4, as a key agent, can activate immune signaling pathways and induce autoimmune cytokines expression. 2. It is suggested to reconsider the association between periodontal diseases and TAO, as they share the same high-risk population. Controlling periodontal disease severity in TAO studies may provide new clues. 3. For TAO treatment, endovascular intervention and autologous cell therapy both showed promising long-term therapeutic effectiveness, in which autologous cell therapy is becoming more popular, although more clinical comparisons are needed.

Cilostazol inhibits hyperglucose-induced vascular smooth muscle cell dysfunction by modulating the RAGE/ERK/NF-κB signaling pathways

Background

Increasing evidence suggests that high glucose (HG) causes abnormalities in endothelial and vascular smooth muscle cell function (VSMC) and contributes to atherosclerosis. Receptor for advanced glycation end-products (RAGE) has been linked to the pathogenesis of both the macrovascular and microvascular complications of diabetes. Cilostazol is used to treat diabetic vasculopathy by ameliorating HG-induced vascular dysfunction.

Objectives

In this study, we investigated whether the cilostazol suppression of HG-induced VSMC dysfunction is through RAGE signaling and its possible regulation mechanism.

Method

We investigated the effect of HG and cilostazol on RAGE signaling in A7r5 rat VSMCs. Aortic tissues of streptozotocin (STZ) diabetic mice were also collected.

Results

Aortic tissue samples from the diabetic mice exhibited a significantly decreased RAGE expression after cilostazol treatment. HG increased RAGE, focal adhesion kinase (FAK), matrix metalloproteinase-2 (MMP-2), intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expressions, and was accompanied with increased reactive oxygen species (ROS), cell proliferation, adhesion and migration. Cilostazol significantly reversed HG-induced RAGE, ROS, downstream gene expressions and cell functions. RAGE knockdown significantly reversed the expressions of HG-induced vasculopathy related gene expressions and cell functions. Cilostazol with RAGE knockdown had additive effects on downstream ERK/NF-κB signaling pathways, gene expressions and cell functions of A7r5 rat VSMCs in HG culture.

Conclusions

Both in vitro and in vivo experimental diabetes models showed novel signal transduction of cilostazol-mediated protection against HG-related VSMC dysfunction, and highlighted the involvement of RAGE signaling and downstream pathways.