【作者】 王晓星；

【导师】 胡卓伟；

【作者基本信息】 北京协和医学院 ， 药理学， 2011， 博士

【摘要】 心脑血管疾病是目前第一大致死因素,严重威胁人类健康。动脉粥样硬化是导致心脑血管疾病的首要病理基础,以血管内脂质、纤维成分堆积,管腔狭窄,血管壁慢性炎症为主要特征,其发生发展与机体免疫系统密切相关。各种免疫细胞,包括单核-巨噬细胞、树突状细胞、T淋巴细胞等在病灶局部浸润并发挥不同功能导致疾病转归或恶化。目前普遍认为免疫失衡是重要的致病因素之一。过去的20年里,他汀类药物因为在降低血脂和降低心血管疾病风险方面的优秀功效,成为预防和治疗动脉粥样硬化的首选和支柱。然而,仍有众多患者最终需要承受急性心血管事件发作的风险。随着对动脉粥样硬化发病机制和影响因素的不断研究,将基础研究向临床应用转化,筛选出更多的治疗靶点,有望为疾病防治带来突破。Toll样受体(Toll like receptors,TLRs)是模式识别受体家族成员,能够识别内、外致病原介导先天免疫反应,同时影响获得性免疫发展方向。大量研究证明TLRs参与动脉粥样硬化的发生发展,尤其TLR2对小鼠动脉粥样硬化发生具有决定作用。我们的实验首次报道,对于已经确立动脉粥样硬化病变的40周龄Apoe-/-小鼠,使用中和性抗体阻断TLR2活性显著改善头臂干血管动脉粥样硬化病变,表现为显著减小斑块面积,管腔狭窄程度和斑块内坏死核心比重,增加中膜厚度,斑块内胶原含量和α-SMA+平滑肌细胞表达,发挥减小和稳定晚期动脉粥样硬化斑块的作用。这种血管保护作用可能与阻断TLR2活性后巨噬细胞募集减少和炎性介质释放降低相关。此外,阻断TLR2活性对于改善过高的内质网应激压力,减少巨噬细胞凋亡有重要贡献。CFX是真菌多糖复合物,能够调节免疫细胞活性,具有强大的免疫调节作用。实验室前期研究证明,CFX能够改善病变组织局部免疫微环境,在肿瘤转移、器官纤维化等疾病模型中展现出良好的效果。应用高脂高胆固醇饮食诱导的Apoe-/-小鼠动脉粥样硬化模型我们初步确定了CFX的血管保护作用,证明1g/kg和3g/kg给予CFX能够显著抑制主动脉内表面病变,减小主动脉根部及头臂干血管斑块面积。使用血管紧张素1型受体拮抗剂厄贝沙坦作为阳性对照,我们发现给予CFX治疗40周龄Apoe-/-小鼠18周能够显著降低血管炎症反应,减小和稳定Apoe-/-小鼠头臂干晚期动脉粥样硬化病变。与动脉粥样硬化相似,肺纤维化也起始于损伤引起的炎症反应,反复的损伤导致免疫反应失调,组织修复失败。我们初步发现TLR5激动剂鞭毛蛋白能够改善博来霉素诱导的小鼠肺纤维化。以TLR5为靶点筛选小分子激动剂可能为新药开发提供更为广阔的前景。更多还原

【Abstract】 Atherosclerosis is the major cause of cardiovascular disease, which increasingly threatens human health worldwide. Depending on lipids lowing effects, statins dramatically decrease clinical events and mortality caused by atherosclerosis. However, heart disease and stroke remain by far the most common causes of death. Thus there is a growing quest for novel drugs in clinical therapy. Inflammatory process plays a major role during different steps, from an early stable atherosclerotic plaque to an advanced plaque prone to rupture. As abnormal immune responses act as an important driving factor, application of immunomodulatory agents offers the possibility of new pharmacological interventions in atherosclerosis.Toll like receptors (TLRs) are a family of pattern-recognition receptors of innate immunity that initiate inflammatory pathways, and their importance in atherosclerosis pathogenesis, especially TLR2, has been well established. In this study, we firstly demonstrated that treatment with anti-TLR2 antibody resulted in reduction and stabilization of advanced atherosclerotic lesions by decreasing the plaque size and necrotic cores, higher expression of collagen andα-SMA in lesions in the brachiocephalic artery of Apoe-/- mice. With the equal effect of TLR2 deficiency, treatment with anti-TLR2 antibody inhibited the accumulation of macrophage in plaques, the expression of inflammatory mediators in the aortas, including MMP-2, TNF-αand IL-6, and the activation of transcription factor NF-κB. ER-stressed macrophage apoptosis in advanced lesions were also dramatically inhibited in the treatment groups, partially depending on regulation of CHOP expression. In summary, the results of this study, compared with recent findings in TLR2-deficient mouse model of atherosclerosis, indicate that anti-TLR2 antibody treatment could act as an effective therapeutic method to protect from advanced atherosclerosis. While TLR2 expressed on endothelial cells is required for disease initiation, in advanced atherosclerotic lesions in which macrophages undergoing apoptosis TLR2 on macrophage surfaces may mediate or amplify the apoptosis signal. So antibodies or antagonists of TLR2 should be developed as a key therapeutic drug in future. CFX is the fermentative polysaccharides of medical mushroom with potent immunomodulatory activity. We found that CFX treatment markedly inhibited the formation of atherosclerosis in the whole aortas, the aortic root and the brachiocephalic arteries of Apoe mice on atherogenic diets. And in Apoe-/-mice with established atherosclerosis, administration of CFX significantly improved advanced atherosclerotic lesions, which were related to suppression of inflammatory responses.Although the detailed mechanisms are still not well understood, inflammatory responses also contribute to the pathogenesis of pulmonary fibrosis, a disease characterized by excessive matrix deposition and destruction of the normal lung architecture. Using the mouse model of bleomycin-induced pulmonary fibrosis, our preliminary findings demonstrated the protective effects of TLR5 agonist on inflammation and fibrosis. These findings will contribute to identifying the new molecular targets of pulmonary fibrosis, and providing research clues for the development of new drugs.更多还原