Suppression of vascular endothelial cell inflammation

描述（申请人提供）：抑制血管内皮细胞炎症，包括适应性免疫和先天免疫，密切调节动脉粥样硬化。血管内皮细胞（ECs）是促炎细胞因子的靶点，如白细胞介素-1b （IL-1b）和肿瘤坏死因子-a （TNF-a）。然而，内皮细胞是否在引发血管炎症中起关键作用这一重要问题仍未明确。特别是，动脉粥样硬化条件下的内皮细胞是否通过新定义的炎性体产生过量的IL-1b的问题仍然未知。因此，本提案的目的是检验一个新的假设，即EC炎症与IL-1b的产生以及随后的EC凋亡在动脉粥样硬化的发病机制中加速。由此推论，抑制EC生成过量IL- 1b和EC凋亡的因子和细胞在动脉粥样硬化中起抑制作用。我们实验室的初步数据和其他实验室的报告清楚地支持这一假设：(i)微生物感染在动脉粥样硬化的发病机制中起作用。在细菌脂多糖（LPS）的刺激下，来自致动脉粥样硬化载脂蛋白e缺陷小鼠的小鼠主动脉内皮细胞（MAECs）表达的亲il -1b水平高于野生型对照小鼠的MAECs。磷脂酰肌醇3-激酶（PI-3K）抑制剂Wortmannin和Ly294002存在时，ApoE-/-小鼠MAECs中il -1b的表达上调，表明PI3K-Akt存活途径抑制il -1b生成的EC炎症；（ii）我们发现了一种新的Bcl-xL相互作用的抗凋亡蛋白TCTP。TCTP是PI3K- Akt存活通路上重要的调控蛋白和抗凋亡蛋白。此外，在ECs中，TCTP在LPS刺激下也下调，提示抗TCTP可能作为PI-3K-Akt通路信号传导的ECs保护机制，抑制EC炎症和凋亡。此外，我们发现，ApoE-/-小鼠MAECs与CD4+CD25highFoxp+调节性T细胞（Tregs）共培养，导致前il -1b表达降低，以响应LPS，表明免疫抑制性Tregs抑制EC炎症；（iii） IL-1b缺乏抑制EC炎症和动脉粥样硬化。因此，阐明il -1b对EC炎症和EC凋亡的抑制机制具有重要的临床意义，可能为动脉粥样硬化和血管炎症的治疗提供新的治疗方法。这一目标将通过执行以下具体目标来实现：(1)确定与野生型对照小鼠相比，在致动脉粥样硬化的ApoE-/-小鼠中，产生il -1b的EC炎症是否加速；(2)检测TCTP和PI3K-Akt细胞内信号通路是否抑制ApoE-/-小鼠il -1b生成的EC炎症和EC凋亡；(3)观察Tregs细胞外抑制il -1b生成的EC炎症和EC凋亡是否能减轻ApoE-/-小鼠的动脉粥样硬化。公共卫生相关性：越来越多的证据表明血管内皮细胞（ECs）炎症显著促进动脉粥样硬化的发展。然而，内皮细胞是否在引发血管炎症中起关键作用这一重要问题仍未明确。这些研究将有助于更好地理解il -1b对EC炎症和EC凋亡的抑制机制的阐明是否可以促进动脉粥样硬化和血管细胞炎症治疗新疗法的发展。

DESCRIPTION (provided by applicant): Suppression of vascular endothelial cell inflammation both adaptive and innate immunity tightly regulate atherosclerosis. Vascular endothelial cells (ECs) are targets of proinflammatory cytokines, such as interleukin-1b (IL-1b) and tumor necrosis factor-a (TNF-a). However, the important question of whether ECs play a critical role in initiating vascular inflammation remains poorly defined. In particular, the issue of whether ECs in atherogenic conditions generate excess IL-1b via the newly-defined inflammasome remains unknown. Therefore, the goal of this proposal is to examine a novel hypothesis that EC inflammation with the generation of IL-1b followed by EC apoptosis is accelerated in the pathogenesis of atherosclerosis. The corollary hypothesis is that factors and cells in suppressing EC generation of excess IL- 1b and EC apoptosis play inhibitory roles in atherogenesis. Preliminary data from our lab and reports from others' labs clearly support this hypothesis: (i) Microbial infections play a role in the pathogenesis of atherosclerosis. In response to the stimulation of bacterial lipopolysaccharide (LPS), mouse aortic ECs (MAECs) from atherogenic apolipoprotein E-deficient ApoE-/- mice express higher levels of pro-IL-1b than MAECs from wild-type control mice. The upregulation of pro-IL-1b in MAECs from ApoE-/- mice is increased in the presence of phosphatidylinositol 3-kinase (PI-3K) inhibitors Wortmannin and Ly294002, suggesting that PI3K-Akt survival pathway suppresses IL-1b-generating EC inflammation; (ii) We have identified a novel Bcl-xL interacting, anti-apoptotic protein TCTP. TCTP is an important regulator and anti-apoptotic protein along PI3K- Akt survival pathway. In addition, TCTP is also down-regulated in response to LPS stimulation in ECs, suggesting that anti-TCTP may inhibit EC inflammation and apoptosis as a PI-3K-Akt pathway-signaled protective mechanism of ECs. In addition, we found that co-culture of MAECs from ApoE-/- mice with CD4+CD25highFoxp+ regulatory T cells (Tregs) results in decreased pro-IL-1b expression in response to LPS, suggesting that immunosuppressive Tregs suppress EC inflammation; (iii) IL-1b deficiency inhibits EC inflammation and atherogenesis. Therefore, the elucidation of the suppressive mechanisms of IL-1b-generating EC inflammation and EC apoptosis is clinically significant, as it may lead to new therapeutics for treating atherosclerosis and vascular inflammation. This goal will be pursued through the execution of the following specific aims: (1) To determine whether IL-1b-generating EC inflammation is accelerated in atherogenic ApoE-/- mice in comparison to that in wild-type control mice; (2) To determine whether TCTP and PI3K-Akt intracellular signaling pathway inhibits IL-1b-generating EC inflammation and EC apoptosis in ApoE-/- mice; and (3) To determine whether extracellular suppression of IL-1b-generating EC inflammation and EC apoptosis by Tregs attenuates the atherogenesis in ApoE-/- mice. PUBLIC HEALTH RELEVANCE: There is increasing evidence that vascular endothelial cell (ECs) inflammation significantly contributes to the development of atherosclerosis. However, the important question of whether ECs play a critical role in initiating vascular inflammation remains poorly defined. The proposed studies will provide better understanding whether the elucidation of the suppressive mechanisms of IL-1b-generating EC inflammation and EC apoptosis can lead to the development of new therapeutics for treating atherosclerosis and vascular cell inflammation.