Suppression of vascular endothelial cell inflammation

描述（申请人提供）：血管内皮细胞炎症的抑制，适应性免疫和先天免疫都能严格调节动脉粥样硬化。血管内皮细胞（EC）是促炎细胞因子如白细胞介素-1b（IL-1b）和肿瘤坏死因子-α（TNF-α）的靶细胞。然而，EC是否在引发血管炎症中起关键作用的重要问题仍然定义不清。特别是，在致动脉粥样硬化条件下的EC是否通过新定义的炎性小体产生过量的IL-1b的问题仍然未知。因此，本研究的目的是研究一种新的假说，即EC炎症与IL-1b的产生，随后EC凋亡在动脉粥样硬化的发病机制中加速。推测抑制EC产生过量IL- 1b和EC凋亡的因子和细胞在动脉粥样硬化形成中起抑制作用。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发挥作用。在对细菌脂多糖（LPS）刺激的反应中，来自致动脉粥样硬化载脂蛋白E缺陷型ApoE-/-小鼠的小鼠主动脉内皮细胞（MAEC）比来自野生型对照小鼠的MAEC表达更高水平的pro-IL-1b。在磷脂酰肌醇3-激酶（PI-3 K）抑制剂Wortmannin和Ly 294002的存在下，来自ApoE-/-小鼠的MAEC中的pro-IL-1b的上调增加，表明PI 3 K-Akt存活途径抑制产生IL-1b的EC炎症;（ii）我们已经确定了一种新的Bcl-xL相互作用的抗凋亡蛋白TCTP。TCTP是沿着PI 3 K-Akt存活通路的重要调节因子和抗凋亡蛋白。此外，TCTP也在EC中响应于LPS刺激而下调，这表明抗TCTP可以抑制EC炎症和凋亡，作为PI-3 K-Akt通路信号的EC保护机制。此外，我们发现，来自ApoE-/-小鼠的MAEC与CD 4 + CD 25 highFoxp+调节性T细胞（TCLs）的共培养导致响应于LPS的pro-IL-1b表达降低，表明免疫抑制性TCLs抑制EC炎症;（iii）IL-1b缺乏抑制EC炎症和动脉粥样硬化形成。因此，阐明产生IL-1b的EC炎症和EC凋亡的抑制机制具有临床意义，因为它可能导致治疗动脉粥样硬化和血管炎症的新疗法。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）确定TCTP和PI 3 K-Akt细胞内信号通路是否抑制ApoE-/-小鼠中产生IL-1b的EC炎症和EC凋亡;以及（3）确定TdR对产生IL-1b的EC炎症和EC凋亡的细胞外抑制是否减轻ApoE-/-小鼠的动脉粥样硬化形成。公共卫生相关性：越来越多的证据表明，血管内皮细胞（ECs）炎症显著有助于动脉粥样硬化的发展。然而，EC是否在引发血管炎症中起关键作用的重要问题仍然定义不清。拟议的研究将提供更好的理解是否IL-1b产生EC炎症和EC凋亡的抑制机制的阐明可以导致治疗动脉粥样硬化和血管细胞炎症的新疗法的发展。

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.