miR-155通过预激和活化双重途径激活NLRP3炎症小体参与颈动脉粥样硬化斑块形成的机制研究

Carotid atherosclerosis is the main pathogenesis of ischemic stroke. Our previous experiments showed that miR-155 is related to the activation of NLRP3 inflammasomes in ApoE-/- AS mice and increase the production of IL-1β and IL-18 and the plaque size. But the detailed pathways of miR-155 regulating the NLRP3 inflammasomes activation are still unclear. We propose the assumption that miR-155 activate the NLRP3 inflammasomes by the dual pathways of expressing and assembling. (1)miR-155 suppresses the MST2 expression and activates the RAS\RAF\MEK/ERK signal pathway and NF-κB pathway, which promote the NLRP3 inflammasomes expressing by a positive feedback. (2) miR-155 activates the P2X7R and promotes the assembling of NLRP3 inflammasomes. In order to testify our assumption, we are going to detect the expression of MST2, RAS, RAF, MEK, ERK, NF-κB, P2X7R, NLRP3, ASC, pro-caspase-1 and IL-1β、IL-18 precursor protein in AS carotid plaques of patients and ApoE-/- AS mice; study the effect of interventions on MST2, RAS, RAF, MEK, ERK and NF-κB on the miR-155-induced expression of NLRP3-related protein and IL-1β、IL-18 precursor protein.; study the effect of interventions on P2X7R on miR-155-induced NLRP3 inflammasomes assembling and the production of IL-1β、IL-18; study the effect of interventions on MST2, RAS, RAF, MEK, ERK, NF-κB and P2X7R on plaque formation and inflammation in ApoE-/- AS mice. This project helps to reveal the pathological mechanism of carotid AS plaques, and provide potential therapeutic targets for prevention and treatment of carotid AS and ischemic stroke.

颈动脉粥样硬化（AS）是缺血性卒中的重要病因。我们在AS模型小鼠发现miR-155激活NLRP3炎症小体可增加IL-1β的产生参与斑块形成，但其激活机制未明。我们提出miR-155可能通过预激和活化双重途径激活NLRP3炎症小体的假说：①miR-155可抑制MST2表达而激活MEK/ERK/NF-κB通路，正反馈促进NLRP3炎症小体预激；②miR-155可激活核苷酸P2X受体促进NLRP3炎症小体活化。为验证该假说，我们拟在患者及AS模型小鼠斑块中检测miR-155、NLRP3激活相关蛋白和上述各通路分子的表达；研究干预MST2/ERK/NF-κB通路对miR-155诱导NLRP3炎症小体预激的影响；研究干预P2X7R对miR-155诱导NLRP3炎症小体活化的影响；在AS模型小鼠研究干预MST2、NF-κB和P2X7R对斑块形成的影响。本课题将为防治颈AS和缺血性卒中提供可能治疗靶点。

颈动脉粥样硬化（AS）是缺血性卒中的重要病因。我们在AS模型小鼠发现miR-155激活NLRP3炎症小体可增加IL-1β的产生参与斑块形成，但其激活机制未明。通过离体实验我们发现miR-155可通过ERK/NF-κB通路对ox-LDL诱导的单核巨噬细胞中的NLRP3炎性小体激活发挥调节作用；并且后续在动物模型中证实干预miR-155和ERK通路均可影响NLRP3炎症小体激活，从而调控AS斑块的形成和发展过程。本课题成果为阐明脑动脉粥样硬化的分子发病机制夯实理论基础，将为防治颈AS和缺血性卒中提供可能治疗靶点。