Inhibition of Radiation-Induced Coronary Microvascular Disease

摘要 本申请旨在满足FOA-PA-19-112的科学目标。冠状动脉微血管 疾病(CMD)是癌症幸存者胸部放射治疗的主要后遗症。封堵较大的冠状动脉 动脉可以通过支架或外科分流术来治疗；然而，目前还没有有效的治疗方法。 瞄准CMD。这个项目的目的是研究新的和以前未探索的电离机制。 辐射(IR)诱导的冠脉微血管损伤，并测试小分子N-乙酰-2-氨基丁酸的有益作用。 丝氨酸-天冬氨酸-赖氨酸-Pro(Ac-SDKP)，以抵消这些影响。这项建议的科学前提是基于我们的 最近的研究表明，冠状动脉内皮细胞损伤严重，冠状动脉血管明显增加 啮齿动物胸部辐射暴露后的通透性和纤维化。我们还发现，辐射诱导的CMD 与Claudin-1(Cldn1)表达的转录抑制呈剂量依赖关系。重要的是 Ac-SDKP，一种胸腺素β4衍生的内源性多肽，归一化内皮细胞 通透性，重组的cldn1，并减少心脏纤维化。 尽管ac-SDKP具有保护心脏的潜力，但由于以下原因，其治疗应用一直具有挑战性 其在血清中的半衰期较短(半衰期为4.5分钟)。因此，我们开发了稳定的脂质体Ac-SDKP(Lip-SDKP)。 AC-SDKP)配方，我们打算测试其持续的系统性影响。我们假设Ac-SDKP 减轻辐射引起的冠状动脉内皮损伤，防止微血管渗漏 抑制IR介导的cldn1丢失。在目标I中，我们将检测Lip-Ac-的摄取效率和生物活性。 心脏和冠脉微血管内皮细胞中的SDKP。在AIM II中，我们将研究AC-2的影响。 SDKP对辐射后内皮细胞屏障完整性的影响，并研究cldn1在这一过程中的作用。在AIM III中，我们 将确定Ac-SDKP治疗对放射诱导的冠脉血流和局部和 全球心脏功能。 我们将通过使用先进的分子生物学和成像方法来实现这些目标。我们有 开发了一种新的内皮细胞特异性cldn1基因工程小鼠模型。 功能。我们还利用下一代体内siRNA开发了一种cldn1功能丧失模型。 交付技术。此外，我们将利用荷瘤的同基因和异种移植模型来检查 多剂量胸部照射后的AC-SDKP效应。这个项目将提供关于 Ac-SDKP对放射性CMD的保护作用及其重要的治疗意义 对易受放射治疗引起的CMD和心脏疾病的癌症患者进行及时和有针对性的干预 缺血症。

ABSTRACT This application is designed to address the scientific goals of FOA-PA-19-112. Coronary microvascular disease (CMD) is major sequelae of chest radiotherapy in cancer survivors. Blockade of the larger coronary arteries can be treated by stents or surgical bypass; however, there are no effective therapies currently available to target CMD. This project aims to investigate the novel and previously unexplored mechanisms of ionizing radiation (IR)-induced coronary microvascular injury, and test the beneficial effects of a small molecule, N-acetyl- ser-asp-lys-pro (Ac-SDKP), to counteract these effects. The scientific premise of this proposal is based on our recent studies demonstrating profound endothelial cell injury with marked increase in coronary vascular permeability, and fibrosis, after thoracic radiation exposure in rodents. We also found that radiation-induced CMD was dose-dependently associated with the transcriptional inhibition of claudin-1 (cldn1) expression. Importantly, administration of Ac-SDKP, a thymosin β4-derived endogenous peptide, normalized endothelial cell permeability, reconstituted cldn1, and reduced cardiac fibrosis. Despite its cardioprotective potential, therapeutic application of Ac-SDKP has been challenging due to its short half-life (T1/2 of 4.5 mins) in serum. Therefore, we have developed a stable, liposomal Ac-SDKP (Lip- Ac-SDKP) formulation, which we intend to test for sustained systemic effects. We hypothesize that Ac-SDKP mitigates radiation-induced coronary endothelial damage, and prevents microvascular leakage by inhibiting IR-mediated cldn1 loss. In Aim I, we will examine the uptake efficiency and bioactivity of Lip-Ac- SDKP in the heart and in coronary microvascular endothelial cells. In Aim II, we will examine the effects of Ac- SDKP on endothelial barrier integrity after radiation and study the role of cldn1 in this process. In Aim III, we will determine the effects of Ac-SDKP treatment on radiation-induced coronary blood flow and regional and global cardiac function. We will accomplish these aims by using advanced molecular biology and imaging approaches. We have developed a novel genetically engineered mouse model of endothelial cell-specific cldn1 gain-of- function. We have also developed a cldn1 loss-of-function model using a next generation in vivo siRNA delivery technology. Additionally, we will utilize tumor-bearing syngeneic and xenograft models to examine Ac-SDKP effects after multi-dose thoracic irradiation. This project will provide mechanistic insight on the protective effects of Ac-SDKP against radiation-induced CMD, and will have important therapeutic implications for timely and targeted interventions in cancer patients susceptible to radiotherapy-induced CMD and cardiac ischemia.