Department of Neurology, Shaanxi Provincial People's Hospital, No. 256 West Friendship Rd, Xi'an, China, 710068.
Department of Neurology, Shaanxi Provincial People's Hospital, No. 256 West Friendship Rd, Xi'an, China, 710068.
J Stroke Cerebrovasc Dis. 2021 Feb;30(2):105489. doi: 10.1016/j.jstrokecerebrovasdis.2020.105489. Epub 2020 Dec 1.
Ischemic stroke is clearly affected by microRNAs (miRNAs) due to dysfunction of their regulatory networks. Our clinical data confirmed decreased miR-221 levels in plasma collected from patients with acute ischemia compared with plasma from healthy controls. Therefore, we further aimed to demonstrate the regulatory mechanisms by which miR-221 exerts its neuroprotective effects in acute ischemic brain injury.
Middle cerebral artery occlusion (MCAO) was used to establish focal cerebral ischemia in adult male C57BL/6 mice. A miR-221 mimic or a negative mimic control was injected by intracerebroventricular administration 24 h prior to MCAO. After 48 h, cerebral infarction volume and neurological scores were calculated, and to determine the extent of neuroprotection by miR-221, neurobehavioral tests were performed. Quantitative real-time PCR, ELISA, and flow cytometry were also performed to identify the expression of inflammation-related cytokines and chemokines as well as infiltration/activation of various immune cells in the brain.
The results showed that MCAO mice treated with a miR-221 mimic exhibited significantly decreased cerebral infarction volume and increased amelioration of behavioral deficits. Moreover, the expression of proinflammatory cytokines (TNF-α, MCP-1, VCAM-1, and IL-6) and chemokines (CCL2 and CCL3) was significantly decreased in the miR-221 mimic-treated group. In addition, the flow cytometry data showed that macrophage infiltration and microglial activation were blocked by miR-221 treatment.
our results indicate that miR-221 could decrease brain damage in the setting of acute ischemic stroke by inhibiting the proinflammatory response, which furthered our understanding of the molecular basis of miR-221 and provided a new potential therapeutic target for the treatment of ischemic stroke .
由于其调控网络的功能障碍，缺血性中风明显受到 microRNAs（miRNAs）的影响。我们的临床数据证实，与健康对照组的血浆相比，急性缺血患者血浆中的 miR-221 水平降低。因此，我们进一步旨在证明 miR-221 在急性缺血性脑损伤中发挥其神经保护作用的调节机制。
使用大脑中动脉闭塞（MCAO）在成年雄性 C57BL/6 小鼠中建立局灶性脑缺血。在 MCAO 前 24 小时通过脑室内注射 miR-221 模拟物或阴性模拟物对照物。48 小时后，计算脑梗死体积和神经评分，并通过神经行为测试确定 miR-221 的神经保护程度。还进行了定量实时 PCR、ELISA 和流式细胞术，以鉴定炎症相关细胞因子和趋化因子的表达以及各种免疫细胞在大脑中的浸润/激活。
结果表明，用 miR-221 模拟物处理的 MCAO 小鼠表现出明显减小的脑梗死体积和改善的行为缺陷。此外，在 miR-221 模拟物处理组中，促炎细胞因子（TNF-α、MCP-1、VCAM-1 和 IL-6）和趋化因子（CCL2 和 CCL3）的表达显著降低。此外，流式细胞术数据表明，miR-221 处理可阻断巨噬细胞浸润和小胶质细胞激活。
我们的结果表明，miR-221 可通过抑制促炎反应减少急性缺血性中风中的脑损伤，进一步了解了 miR-221 的分子基础，并为缺血性中风的治疗提供了新的潜在治疗靶点。
