SDF-1/CXCR4自噬轴介导的巨噬细胞焦亡在情志所伤加重AS斑块易损性的作用及其机制研究

Plaque rupture and thrombosis compose the main pathogenesis of acute coronary syndrome. Our preliminary study found emotional stress was a crucial factor that caused vulnerable plaque formation and SDF-1/CXCR4 biological axis dysfunction in the plasma, platelets, aortas. And the dysfunction was positively correlated with the severity of plaque vulnerability. However, it remains unclear if there is a direct correlation between vulnerable plaque rupture and the SDF-1/CXCR4 signalling pathway in stressed mice. Recently, it’s reported that the chemokine SDF-1 and CXCR4, as new genetic biomarkers to judge the level of autophagy independently, are the key signal to regulate the function of pyroptosis, which is the initiator of endogenous risk related molecular model of atherosclerosis. Therefore, we bring forward the new assumption that emotional stress induces vulnerable plaque rupture via macrophage pyroptosis mediated by SDF-1/CXCR4 autophagy axis. We plan to establish a vulnerable plaque model in ApoE-/- mice and AS cell model in vitro, using the technology of siRNA, adenovirus, molecular biology, etc. We will reveal the pivotal role and the molecular mechanism which can clarify emotional stimulation aggravated AS plaque vulnerability via regulating macrophage pyroptosis mediated by SDF-1/CXCR4 autophagy axis. Our study will provide scientific evidence for therapeutic target and characteristic biological markers which can prevent vulnerable plaque early.

易损斑块破裂和血栓形成是急性冠脉综合征（ACS）的主要发病机制。我们的前期研究发现：情志刺激导致易损斑块模型小鼠血浆及主动脉组织SDF-1/CXCR4轴表达失衡，其失衡与斑块易损性严重程度成正相关，但二者之间直接联系的分子靶点尚不明确。最近文献报道：趋化因子SDF-1/CXCR4可作为独立判断自噬水平的新基因生物标记物，SDF-1/CXCR4自噬轴是调节细胞焦亡的关键信号，而细胞焦亡是动脉粥样硬化（AS）内源性危险相关分子模式的开启者。据此我们提出“情志刺激通过SDF-1/CXCR4自噬轴介导的巨噬细胞焦亡加重AS斑块易损性”的研究设想。拟在整体和细胞水平复制易损斑块小鼠模型及体外AS模型，采用siRNA、腺病毒、分子生物学等技术，阐明SDF-1/CXCR4自噬轴调控巨噬细胞焦亡在情志刺激加重AS斑块易损性中的关键作用及其分子机制，为寻找早期识别易损斑块的特征性指标和干预靶点提供科学依据。

动脉粥样硬化（atherosclerosis，AS）AS是心脑血管疾病的重要病理基础，而AS易损斑块则是急性心血管疾病发生的重要因素。因此，本研究中利用相关动物和细胞模型，探讨SDF-1/CXCR4自噬轴调控巨噬细胞焦亡在情志刺激加重AS斑块易损性中的关键作用及其分子机制。研究发现，情志刺激导致易损斑块模型小鼠血浆及主动脉组织SDF-1/CXCR4轴表达失衡，且与斑块易损性严重程度成正相关。与空白对照组、正常对照组和高脂组比较，CUMS组小鼠主动脉中油红O染色显示动脉粥样硬化程度明显加重，血浆SDF-1和CXCR4含量显著增加（P<0.05），免疫组化可见主动脉组织 SDF-1和 CXCR4的平均吸光度显著升高（P<0.05）。Western blot检测结果显示，CUMS组小鼠血小板、主动脉和海马中SDF-1和CXCR4的表达量显著增加（P<0.05），骨髓中SDF-1和CXCR4的表达量显著降低（P<0.05）。使用ox-LDL诱导巨噬细胞泡沫化，有效建立泡沫细胞模型后，使用葛根素进行干预，高中低剂量的葛根素均能抑制脂质在巨噬细胞内沉积（P＜0.01），下调IL-6、TNF-α、IL-1β等炎性细胞因子的mRNA水平（P＜0.01），同时抑制细胞焦亡蛋白NLRP3、cleaved-Caspase1表达（P＜0.01），并呈现剂量依赖性。体外建立PC12和BV2体外OGD/R模型，结果提示BMSC-Exos可以有效抑制神经元炎症和焦亡相关蛋白的表达，同时可抑制M1型小胶质细胞的表达，促进M2型小胶质细胞的表达，且BV2细胞的极化状态影响PC12细胞焦亡。研究表明，SDF-1/CXCR4表达失调可能是情志刺激加速动脉粥样硬化进展的关键靶点通路；葛根素可能通过抑制ox-LDL诱导的巨噬细胞NLRP3/Caspase1焦亡信号通路额活化，下调炎性细胞因子表达，稳定AS易损斑块；BMSC-Exos可通过抑制NLRP3介导的炎症小体和调节小胶质细胞极化的炎症和焦亡以改善脑I/R损伤。研究结果初步揭示情志所伤是促发易损斑块破裂的重要因素之一，阐述肝郁气滞导致易损斑块破裂的关系，探讨心脑血管疾病中焦亡介导的炎症机制，为寻找早期识别易损斑块的特征性指标和干预靶点提供科学依据。