首参颗粒调控p66Shc表达抑制动脉粥样硬化的机制

Atherosclerosis (AS) is one of the major threats of human health. p66Shc, a key aging-related gene, promotes the occurrence and development of AS. Shou'shen Granules could effectively intervene AS. However, the mechanisms underlying the role of Shou'shen Granules in intervening AS remain largely unknown. In previous studies, we found that: NSun2 methylated p66Shc mRNA in the 3'UTR, enhanced the translation of p66Shc, thereby elevating the expression of p66Shc; Shou'shen Granules could effectively diminish the effect of high fat diet in inducing the expression of NSun2 and p66Shc in the aorta tissue of ApoE-deficient mice. Based on above findings, we set out to investigate the mechanism underlying the translational regulation of p66Shc by NSun2-mediated methylation of p66Shc 3'UTR, to address whether Shou'shen Granules could repress the expression of p66Shc and cell senescence through inhibiting NSun2 expression; and to eventually answer the question whether Shou'shen Granules could intervene the process of AS by influencing the NSun2-p66Shc regulatory process. Our study will identify the effective target of Shou'shen Granules and elucidate the molecular mechanism by which Shou'shen Granules intervening AS, and to provide experimental evidence for the treatment and prevention of AS by traditional Chinese medicine.

动脉粥样硬化（AS）是人类健康的主要威胁之一。衰老相关基因p66Shc促进AS的发生发展。补肾中药复方"首参颗粒"可抑制AS病变，但机制尚未阐明。本课题前期研究发现：tRNA甲基转移酶NSun2可甲基化p66Shc mRNA，促进p66Shc翻译，上调其表达；"首参颗粒"可逆转高脂饮食对ApoE-/-小鼠主动脉血管组织NSun2及p66Shc表达的诱导。 本课题将在此基础上进一步探讨NSun2介导的3'UTR甲基化促进p66Shc翻译的机制；探讨"首参颗粒"可否通过下调NSun2抑制p66Shc表达及衰老；论证"首参颗粒"可否通过下调NSun2表达干预NSun2-p66Shc调控过程进而抑制AS病变。这些研究将解析"首参颗粒"通过调控衰老相关基因表达抑制AS病变的效应靶点和分子机制，为中医药防治AS提供新的策略和依据。

动脉粥样硬化是人类健康的主要威胁之一。衰老相关基因p66Shc可促进其发生发展。但是p66Shc的作用机制暂不明确。本研究中，我们首先成功建立了NSun2+/-转基因大鼠模型；其次，利用H2O2建立p66Shc高表达的血管内皮细胞氧化应激衰老模型；同时，利用茴香霉素干预建立p66Shc高表达的神经元氧化应激衰老细胞模型。通过运用上述细胞模型，筛选到了多个中药单体（特女贞苷、远志皂苷元、红景天苷、补骨脂素、没食子酸等）通过有效降低细胞内源性p66Shc的表达，削弱茴香霉素所致的细胞老化和细胞毒性。接着，我们研究了血管内皮细胞衰老过程中，tRNA甲基转移酶NSun2对p66Shc mRNA的甲基化修饰的调控机制。研究结果表明，Nsun2介导p66Shc mRNA发生高甲基化修饰，其结果使得ROS，p38MAPK等被激活，从而加速氧化应激和高浓度葡萄糖诱导的人血管内皮细胞（HUVEC）衰老。此外，我们还阐明了红景天苷通过调控血管内皮细胞Rb蛋白磷酸化，促进其细胞周期从G0/G1期进入S期，从而抑制氧化低密度脂蛋白（oxLDL）诱导的血管内皮细胞衰老的调控机制，为进一步阐明氧化应激诱导动脉粥样硬化的发生及研发有效的治疗动脉粥样硬化药物提供理论依据。最后，我们通过在小鼠动脉粥样硬化模型ApoE-/-上杂交p66Shc+/-小鼠，成功制备抗ApoE-/-&p66Shc+/-抗衰老动脉粥样硬化小鼠模型，用于讨论延缓衰老背景下，动脉粥样硬化发生发展的机制。在上述模型小鼠上施加补肾中药“首参颗粒”后发现，其可以通过缓解ASK1-p38通路的活化，来实现对动脉粥样硬化小鼠血管内皮细胞损伤的治疗作用。上述研究成果将为“首参颗粒”防治动脉粥样硬化提供新的策略和依据。