Regulation of brain endothelial integrity by angiotensin receptors as treatment for cerebral malaria

血管紧张素受体调节脑内皮完整性治疗脑型疟疾

• 批准号: 10350640
• 负责人: ANA RODRIGUEZ
• 金额: $ 32.2万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10350640
• 关键词: AGTR2 gene; Affect; Agonist; Angiotensin Receptor; Angiotensins; Antimalarials; Apoptosis; Binding; Biological Assay; Blood; Blood - brain barrier anatomy; Brain; Brain Diseases; Cardiovascular system; Cause of Death; Cells; Cerebral Malaria; Cessation of life; Characteristics; Complication; Concentration Camps; Development; Disease model; Edema; Electrical Resistance; Embryo; Endothelial Cells; Endothelium; Erythrocytes; Fingerprint; Foundations; Genetic Models; Goals; Hemorrhage; Human; Immunofluorescence Immunologic; Impaired cognition; In Vitro; Individual; Intercellular Junctions; Knock-out; Knockout Mice; Life; Maintenance; Malaria; Maps; Mediating; Modeling; Mus; Outcome; Parasites; Pathology; Patients; Permeability; Pharmacology; Plasmodium falciparum; Pre-Clinical Model; Predisposition; Proteins; Receptor Signaling; Regulation; Renin-Angiotensin System; Role; Second Messenger Systems; Sequence Homology; Signal Transduction; Signaling Molecule; Small Interfering RNA; Syndrome; Testing; Therapy Clinical Trials; Type 2 Angiotensin II Receptor; Virulent; Wild Type Mouse; angiotensin I (1-7); antagonist; arm; beta catenin; blood-brain barrier disruption; brain endothelial cell; brain tissue; endothelial dysfunction; experimental study; in vitro Assay; in vitro Model; in vivo; irbesartan; kidney cell; peptide analog; pre-clinical; prevent; protective effect; receptor; response; treatment effect

Summary. Cerebral malaria (CM) remains the most virulent and deadliest manifestation of malaria. It is caused by Plasmodium falciparum infected erythrocytes (iRBC) adhering to host brain endothelial cells and compromising the blood brain barrier. While available anti-malarial drugs are effective at clearing parasites from the blood, they do not have specific effects against CM. We have found that P. falciparum-iRBC induced disruption of human brain microvascular endothelial cell junctions was prevented by the activation of the angiotensin (Ang) II receptor type 2 (AT2), achieving protection of endothelial integrity. We also found that AT2 agonists are protective against experimental CM, and mice deficient in the AT2 receptor are more susceptible to this syndrome. However, over the last years, we have expanded the renin-angiotensin system by identifying additional receptors (Mas and MrgD) that are activated by agonists similar or equal to AT2 agonists, such as C21, Ang-(1-7) and Ang-(1-9). We could also show that these compounds are protective against P. falciparum-induced disruption of endothelial integrity. Thus, we hypothesize that activation of one, two, or all three receptors of the beneficial arm of the renin- angiotensin system protects brain endothelial cells from parasite-induced disruption of their barrier function. To identify which receptor(s) are key in the protection of endothelial integrity, we will first quantify the effect of Ang-(1-9), Ang-(1-7) and C21 in receptor-transfected HEK293 cells and in human and murine brain endothelial cells on intracellular signaling molecules, known to be regulated by the agonists and important in the maintenance of endothelial barrier integrity. Receptor blockers targeting different angiotensin receptors will be tested for their ability to block the intracellular signaling induced by the protective Ang peptides/analogues. Primary endothelial cells will be also targeted with siRNA against AT2 and/or Mas and/or MrgD to identify the responsible receptor(s) for the signaling effects. Finally, primary brain endothelial cells isolated from mice deficient in one, two or three receptors will be used as a genetic model to confirm the conclusions made from the pharmacological and siRNA experiments. We will then identify the receptors involved in the protection mediated by Ang-(1-9), Ang-(1-7), and C21 of brain endothelial cells from P. falciparum-induced endothelial disruption. We will use a pharmacological approach with the receptor antagonists and siRNA against the receptors to determine their effects on endothelial activation and junction integrity and on selected second messengers. Finally, we will test how treatment with Ang-(1-9), Ang-(1-7) and C21 affects the outcome of CM in wild-type and genetically deficient mice in one of the three receptors as well as double and triple knockouts. The main goal of this project is to identify the angiotensin receptor(s) that mediate protection of endothelial integrity during CM. Our results will lay the foundation for the development of agonists against this receptor(s) as adjunct therapy for CM and potentially for other diseases where brain endothelial integrity is compromised.

概括。脑疟疾（CM）仍然是疟疾中最有毒，最致命的表现。这是 由恶性疟原虫感染的红细胞（IRBC）引起 损害血脑屏障。虽然可用的抗疟疾药物可有效清除寄生虫 从血液中，它们对CM没有特定的影响。 我们发现恶性疟原虫-IRBC诱导人脑微血管内皮细胞的破坏 血管紧张素（ANG）II受体2型（AT2）的激活阻止了连接 保护内皮完整性。我们还发现，AT2激动剂对实验CM具有保护作用 缺乏AT2受体的小鼠更容易受到该综合征的影响。但是，在过去的几年中，我们 通过识别其他受体（MAS和MRGD），扩展了肾素 - 血管紧张素系统 被激动剂激活或等于AT2激动剂，例如C21，Ang-（1-7）和Ang-（1-9）。我们也可以 表明这些化合物可防止恶性疟原虫诱导的内皮完整性破坏。 因此，我们假设肾素有益部门的一个，二或所有三个受体的激活 血管紧张素系统可保护脑内皮细胞免受寄生虫诱导的屏障功能的破坏。 为了确定哪些受体是保护内皮完整性的关键，我们将首先量化 受体转染的HEK293细胞以及人和鼠脑内皮中的Ang-（1-9），Ang-（1-7）和C21 细胞内信号分子的细胞，已知受激动剂调节，在 维护内皮屏障完整性。靶向不同血管紧张素受体的受体阻滞剂将是 测试了它们阻断由保护性ANG肽/类似物诱导的细胞内信号传导的能力。 原代内皮细胞也将用siRNA针对AT2和/或MAS和/或MRGD鉴定 信号效应的负责受体。最后，从小鼠分离的原代脑内皮细胞 一个缺乏一个，两个或三个受体将用作遗传模型，以确认从 药理和siRNA实验。然后，我们将确定保护的受体 由Ang-（1-9），Ang-（1-7）和C21介导了恶性疟原虫诱导的内皮细胞的脑内皮细胞 破坏。我们将使用一种药理学方法与受体拮抗剂和siRNA对抗 受体确定其对内皮激活和连接完整性的影响以及对第二个的影响 使者。最后，我们将测试Ang-（1-9），Ang-（1-7）和C21的治疗如何影响CM的结果 在三个受体之一中的野生型和遗传缺陷的小鼠以及双重敲除。 该项目的主要目标是识别介导内皮保护的血管紧张素受体 CM期间的完整性。我们的结果将为反对这种受体的激动剂开发奠定基础 作为CM的辅助疗法，以及可能损害脑内皮完整性的其他疾病。