Abstract

Atherosclerosis (AS) is the main pathological basis for ischemic cardiovascular and cerebrovascular diseases. Mesenchymal stem cell (MSC)-derived exosomes have the potential to alleviate AS, while the underlying mechanism remains unclear. Here, we aimed to investigate the mechanism of MSC-derived exosomes in AS. The AS mouse model was prepared by feeding ApoE^–/– mice with high-fat diet. AS mice were administered with MSC-derived exosomes, and the atherosclerotic plaque area was analyzed by Oil Red O staining. Mouse RAW264.7 macrophages were incubated with MSC-derived exosomes. The macrophage infiltration, macrophage proportion, and cell migration were estimated by immunohistochemistry, flow cytometry, or Transwell assay. The relationship between miR-21a-5p and kruppel-like factor 6 (KLF6) or extracellular signal-regulated protein kinases 2 (ERK2) was verified by luciferase reporter assay. We found that MSC-derived exosomes promoted M2 polarization of macrophages and reduced plaque area and macrophage infiltration in AS mice. miR-21a-5p overexpression caused an increase of M2 macrophages in RAW264.7 cells and led to a decrease in migration of RAW264.7 cells. Moreover, both KLF6 and ERK2 are the targets of miR-21a-5p. MSC-derived exosomes containing miR-21a-5p promoted M2 polarization of RAW264.7 cells by suppressing KLF6 expression. MSC-derived exosomes containing miR-21a-5p inhibited migration of RAW264.7 cells through inhibiting the ERK1/2 signaling pathway. In conclusion, MSC-derived exosomes containing miR-21a-5p promote macrophage polarization and reduce macrophage infiltration by targeting KLF6 and ERK1/2 signaling pathways, thereby attenuating the development of AS. Thus, MSC-derived exosomes may be a promising treatment for AS.

中文翻译：

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间充质干细胞来源的外泌体 miR-21a-5p 促进 M2 巨噬细胞极化并减少巨噬细胞浸润以减轻动脉粥样硬化

摘要

动脉粥样硬化（AS）是缺血性心脑血管疾病的主要病理基础。间充质干细胞（MSC）衍生的外泌体具有缓解 AS 的潜力，但其潜在机制仍不清楚。在这里，我们旨在研究 MSC 衍生的外泌体在 AS 中的机制。通过喂食 ApoE 制备 AS 小鼠模型^–/–高脂肪饮食的老鼠。给 AS 小鼠施用 MSC 衍生的外泌体，并通过油红 O 染色分析动脉粥样硬化斑块区域。小鼠 RAW264.7 巨噬细胞与 MSC 衍生的外泌体一起孵育。通过免疫组织化学、流式细胞术或 Transwell 测定估计巨噬细胞浸润、巨噬细胞比例和细胞迁移。miR-21a-5p 与 kruppel 样因子 6 (KLF6) 或细胞外信号调节蛋白激酶 2 (ERK2) 之间的关系通过荧光素酶报告基因测定得到验证。我们发现 MSC 衍生的外泌体促进了巨噬细胞的 M2 极化，并减少了 AS 小鼠的斑块面积和巨噬细胞浸润。miR-21a-5p 过表达导致 RAW264.7 细胞中 M2 巨噬细胞增加，并导致 RAW264.7 细胞迁移减少。而且，KLF6 和 ERK2 都是 miR-21a-5p 的靶标。含有 miR-21a-5p 的 MSC 衍生的外泌体通过抑制 KLF6 表达来促进 RAW264.7 细胞的 M2 极化。含有 miR-21a-5p 的 MSC 衍生的外泌体通过抑制 ERK1/2 信号通路来抑制 RAW264.7 细胞的迁移。总之，含有 miR-21a-5p 的 MSC 衍生的外泌体通过靶向 KLF6 和 ERK1/2 信号通路促进巨噬细胞极化并减少巨噬细胞浸润，从而减弱 AS 的发展。因此，MSC 衍生的外泌体可能是一种有希望的 AS 治疗方法。含有 miR-21a-5p 的 MSC 衍生的外泌体通过靶向 KLF6 和 ERK1/2 信号通路促进巨噬细胞极化并减少巨噬细胞浸润，从而减弱 AS 的发展。因此，MSC 衍生的外泌体可能是一种有希望的 AS 治疗方法。含有 miR-21a-5p 的 MSC 衍生的外泌体通过靶向 KLF6 和 ERK1/2 信号通路促进巨噬细胞极化并减少巨噬细胞浸润，从而减弱 AS 的发展。因此，MSC 衍生的外泌体可能是一种有希望的 AS 治疗方法。