Targeting the Host Adenosine A2A Receptor to Protect Against Fatal Rickettsiosis Using an Approved Parkinson's Disease Drug

使用经批准的帕金森病药物靶向宿主腺苷 A2A 受体来预防致命的立克次体病

• 批准号: 9510124
• 负责人: Bin Gong
• 金额: $ 24.53万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-08 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9510124
• 关键词: ADORA2A gene; Adenylate Cyclase; Adherence; Adhesions; Anatomy; Antibiotic Therapy; Arthropods; Atomic Force Microscopy; Bacteria; Bacterial Adhesins; Bacterial Adhesion; Binding; Biochemical; Biomechanics; Bioterrorism; Cell model; Cell surface; Clinical Trials; Coupling; Cyclic AMP; Data; Disease; Dose; Early Diagnosis; Endothelial Cells; Endothelium; Epidemic; Evaluation; Experimental Designs; Functional Imaging; Human; In Vitro; Infection; Inhalation; Maps; Measures; Methods; Microvascular Permeability; Modeling; Molecular; Mus; Outcome; Parkinson Disease; Pathology; Pharmaceutical Preparations; Play; Proteins; Reporting; Rickettsia; Rickettsia Infections; Rocky Mountain Spotted Fever; Role; Signal Pathway; Signal Transduction; Surface; System; Techniques; Testing; Therapeutic; Typhus; Vaccines; Vascular Endothelial Cell; base; experimental study; human disease; in vivo; insight; molecular recognition; nano; nanomechanical; nanomechanics; novel; prophylactic; protective efficacy; receptor; receptor binding

PROJECT SUMMARY/ ABSTRACT Rickettsioses represent devastating human infections. Epidemic typhus and Rocky Mountain spotted fever (RMSF) are two of the most lethal infections known to humans. Although rickettsial infections can be controlled by appropriate broad-spectrum antibiotic therapy if diagnosed early, up to 20% of misdiagnosed or untreated and 5% of treated RMSF cases can be fatal. In addition, high infectivity and severe illness after inhalation make rickettsiae potential bioterrorism threats. Disseminated endothelial infection and endothelial barrier disruption with increased microvascular permeability are the central pathophysiologic features. However, a vaccine is not available for fatal rickettsioses, and novel host mechanism-based prophylactics and therapeutics are urgently needed. We have reported that cyclic adenosine monophosphate (cAMP) signaling plays a critical role during fatal rickettsioses through the cAMP-exchange protein directly activated by cAMP (Epac) signaling axis. However, the role of upstream signaling pathway in this pathology is completely unknown. Adenosine A2A receptor (A2AR) is predominantly expressed in vascular endothelial cells (ECs). A2AR has been well recognized to serve as an upstream regulator of cAMP signaling and to be able to stimulate the intracellular cAMP accumulation. We found that the approved Parkinson’s disease (PD) drug KW6002, an A2AR antagonist, dramatically suppressed rickettsial infection in both a cell model and a vasculature model. Inactivation of A2AR by KW6002 weakens the nano-binding force of the rickettsial adhesin rOmpB to living endothelial cells (ECs), thereby limiting rickettsial adherence to ECs. These findings suggest that the A2AR- cAMP signaling pathway may control rickettsial infection by acting on host rickettsial-binding receptor(s) in ECs. We propose our central hypothesis that the selective A2AR antagonist KW6002 can provide protective efficacy against rickettsial infection by impeding bacterial adhesion to ECs. To test this hypothesis, we will pursue the following Specific Aims: Aim 1: To identify endothelial surface targets regulated by A2AR during rickettsial adhesion. Aim 2: To define the nanomechanical mechanism of rickettsial adhesion to endothelial surfaces regulated by A2AR. Aim 3: To evaluate whether KW6002 can protect against lethal rickettsial infection by arresting rickettsial adherence to the endothelial lining in vivo. We will test our hypothesis by employing cutting-edge approaches, i.e., 1) functional imaging of the interactions between rickettsial adhesins and living EC surfaces using AFM, and 2) a novel, anatomy-based, in vivo quantitative bacterial adhesion measuring system. Outcomes will provide deeper insights into the biomechanical and molecular mechanisms of rickettsial infections, but more importantly it is expected that the data will support the scientific justification for repurposing an approved drug for immediate use in clinical trials to battle the dreadful human diseases caused by Rickettsia.

项目概要/摘要 立克次体病是毁灭性的人类感染性疾病，包括流行性斑疹伤寒和落基山斑疹热。 (RMSF) 是人类已知的两种最致命的感染，尽管立克次体感染是可以控制的。 如果早期诊断，通过适当的广谱抗生素治疗，高达 20% 的误诊或未经治疗 经治疗的 RMSF 病例中 5% 可能致命。此外，吸入后传染性高且病情严重。 使立克次体成为潜在的生物恐怖威胁。 微血管通透性增加的破坏是主要的病理生理学特征。 疫苗无法用于致命的立克次体病，以及基于宿主机制的新型预防和治疗方法 我们报道了环磷酸腺苷 (cAMP) 信号传导起着至关重要的作用。 通过 cAMP (Epac) 信号直接激活的 cAMP 交换蛋白在致命性立克次体病中发挥作用 然而，腺苷在该病理学中的上游信号通路的作用是完全未知的。 A2A受体(A2AR)主要在血管内皮细胞(EC)中表达。 被认为是 cAMP 信号传导的上游调节因子，能够刺激细胞内 我们发现批准的帕金森病 (PD) 药物 KW6002，一种 A2AR。 拮抗剂，在细胞模型和脉管系统模型中均显着抑制立克次体感染。 KW6002 灭活 A2AR 会削弱立克次体粘附素 rOmpB 对活体的纳米结合力 内皮细胞（EC），从而限制立克次体对 EC 的粘附。这些发现表明 A2AR- cAMP 信号通路可能通过作用于宿主立克次体结合受体来控制立克次体感染 我们提出我们的中心假设：选择性 A2AR 拮抗剂 KW6002 可以提供保护作用。 通过阻止细菌粘附到 EC 来对抗立克次体感染的功效 为了检验这一假设，我们将进行验证。 追求以下具体目标： 目标 1：确定 A2AR 调节的内皮表面靶点 目标 2：确定立克次体与内皮细胞粘附的纳米力学机制。 目标 3：评估 KW6002 是否可以预防致命的立克次体。 通过阻止立克次体粘附到体内内皮细胞来抑制感染。我们将通过以下方式检验我们的假设。 采用尖端方法，即 1) 立克次体粘附素之间相互作用的功能成像 和使用 AFM 的活 EC 表面，以及 2) 一种新颖的、基于解剖学的体内定量细菌粘附 测量系统的结果将为生物力学和分子机制提供更深入的见解。 立克次体感染，但更重要的是，预计数据将支持科学依据 重新利用已批准的药物立即用于临床试验以对抗可怕的人类疾病 由立克次体引起。