Characterization of an 18F COX-2 PET ligand for in vivo brain imaging

用于体内脑成像的 18F COX-2 PET 配体的表征

基本信息

批准号：
10349436
负责人：
Francesca Zanderigo
金额：
$ 50万
依托单位：
NEW YORK STATE PSYCHIATRIC INSTITUTE DBA RESEARCH FOUNDATION FOR MENTAL HYGIENE, INC
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-02-15 至 2024-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10349436
关键词：
Acute Adult Affinity Age Alzheimer&apos s Disease Alzheimer&apos s disease brain Amines Amyotrophic Lateral Sclerosis Anti-Inflammatory Agents Arthritis Autoradiography Binding Biological Assay Biological Markers Blood Blood - brain barrier anatomy Blood specimen Body Weight Brain Brain Diseases Brain imaging Brain region Cell Line Chemicals Clinical Clinical Research Control Groups Cyclotrons Data Development Diagnosis Disease Disease Progression Disseminated Malignant Neoplasm Dose Early Diagnosis Equilibrium Evaluation FDA approved Female Fluorine Gender Goals Half-Life Harvest Hour Image Imaging Device In Vitro Inflammatory Inflammatory Arthritis Kinetics Label Lead Ligands Light Lipopolysaccharides Major Depressive Disorder Malignant Neoplasms Manuals Measurement Measures Methods Modeling Monitor Monkeys Mus National Institute of Mental Health Neuraxis Non-Steroidal Anti-Inflammatory Agents Outcome Outcome Measure PTGS2 gene Pain Parkinson Disease Pathogenesis Pathology Pathway interactions Pharmaceutical Preparations Pharmacology Physiological Play Positron-Emission Tomography Prevention Procedures Process Property Psychotropic Drugs Quantitative Evaluations Radiolabeled Role Scanning Scheme Schizophrenia Senile Plaques Severities Severity of illness Ships Signal Transduction Site Slide Staging Standardization Stimulus Stroke Structure Testing Therapy Evaluation Time Tracer Translating Translations Traumatic Brain Injury Treatment Efficacy accurate diagnosis allograft rejection base blood-brain barrier permeabilization bone cGMP production celecoxib cost effective cyclooxygenase 2 density experimental study imaging study in vitro Assay in vivo in vivo evaluation inhibitor kinetic model lipophilicity male microPET mouse model nervous system disorder neuroinflammation neuropathology non-invasive monitor novel organ transplant rejection overexpression radiochemical response screening program sex skeletal tool treatment response uptake

项目摘要

Alzheimer’s disease (AD) pathogenesis is associated with early neuroinflammation, which is considered to contribute to disease progression and severity. Therefore, understanding and regulating inflammatory pathways in the central nervous system (CNS) may contribute to prevention or delay of AD. Cyclooxygenase-2 (COX-2) is induced in response to inflammatory stimuli, and its inhibition underlies the therapeutic efficacy of many non- steroidal anti-inflammatory drugs (NSAIDs). COX-2 expression is significantly elevated in brain in AD and this elevation correlates with the severity of brain amyloid plaque pathology. Hence, in vivo and non-invasive monitoring of COX-2 level in the brain can track COX-2 induction during the course of AD and also examine the clinical benefits of COX-2 inhibition in AD. A positron emission tomography (PET) ligand to quantify the level of functional COX-2 in the brain would allow direct measurement of neuroinflammation in AD, and thereby enable disease staging and therapy evaluation. However, there is no such PET ligand is currently available. In order to establish a clinically useful PET tracer for COX-2 imaging in AD brain, we propose to evaluate highly potent [18F]- labeled COX-2 inhibitors due to the advantages associated with the 110-minute half-life. [18F]-labeled tracers allow scanning for longer duration so as to enable equilibrium scanning and facilitate robust kinetic studies leading to accurate quantification of COX-2. Moreover, they can be transported from a synthesis hub to nearby PET centers that lack a cyclotron and aid cost-effective PET studies. We identified MTP, a high affinity COX-2 inhibitor (IC50 = 2.2 nM; Figure 2), possessing an aromatic site for introducing [18F]-label that is less susceptible for defluorination. MTP also has adequate lipophilicity (LogP = 2.7) to passively traverse the blood-brain barrier (BBB). We synthesized [18F]MTP and successfully demonstrated its specific binding in COX-2 positive BxPC-3 cell lines (Figure 3, 112). In vivo PET imaging was performed in mice, induced with lipopolysaccharide (LPS), and obtained a significantly higher binding in the brain compared to control mice, with no visible skeletal uptake (Figure 4, 150). Subsequent in vitro autoradiography of slide-mounted sections of the harvested brain, established specific binding of the tracer in LPS-induced neuroinflammation (Figures 5 & 6). In light of the above supporting evidence demonstrating BBB permeability, higher binding in neuroinflammation, and specific binding to COX-2, [18F]MTP will be further evaluated along with two backup ligands 2 & 3 (Figure 2), using additional PET imaging in mice models of neuroinflammation as well as AD neuropathology (Aims 1 & 2). The most qualified tracer identified will undergo test-retest dynamic PET quantitative evaluations with concomitant arterial blood sampling in male and female anesthetized monkeys to quantify binding as total distribution volume in various brain regions (Aim 3). We believe, the proposed experiments would lead to the selection of a successful [18F]- COX-2 PET tracer, characterized for the transition to clinical studies in AD for early diagnosis, monitoring therapeutic response, and aid development of new medications.

阿尔茨海默氏病（AD）发病机理与早期神经炎症有关，这被认为有助于疾病的进展和严重程度。因此，理解和调节中枢神经系统（CNS）的炎症途径可能有助于预防或延迟AD。环氧合酶-2（COX-2）是响应炎症刺激而诱导的，其抑制作用构成了许多非甾体类抗炎药（NSAID）的治疗效率。 AD中大脑中的COX-2表达显着升高，该升高与脑淀粉样菌斑病理的严重程度相关。因此，在大脑中对COX-2水平的体内和非侵入性监测可以在AD过程中跟踪COX-2诱导，并检查AD中COX-2抑制的临床益处。阳性发射断层扫描（PET）配体来量化大脑中功能性COX-2的水平，可以直接测量AD中的神经炎症，从而实现疾病分期和治疗评估。但是，目前没有这样的宠物配体。为了建立用于AD大脑中COX-2成像的临床有用的PET示踪剂，我们建议评估由于与110分钟半衰期相关的优势，因此评估了高潜力[18F]标记的COX-2抑制剂。 [18F]标记的示踪剂可以扫描更长的持续时间，以便能够平衡扫描并促进可靠的动力学研究，从而准确地量化COX-2。此外，它们可以从合成中心运输到缺乏回旋和辅助具有成本效益的PET研究的宠物中心。我们确定了MTP，一种高亲和力COX-2抑制剂（IC50 = 2.2 nm;图2），这是引入[18F]标签的芳族位点，它不太容易屈光。 MTP还具有足够的亲脂性（LOGP = 2.7），可被动地穿越血脑屏障（BBB）。我们合成了[18F] MTP，并成功证明了其在COX-2阳性BXPC-3细胞系中的特定结合（图3、112）。与对照小鼠相比，用脂多糖（LPS）诱导的小鼠进行了体内PET成像，在大脑中获得了明显更高的结合，没有明显的骨骼摄取（图4，150）。随后在收获大脑的幻灯片片段的体外放射自显影，建立了示踪剂在LPS诱导的神经炎症中的特定结合（图5和6）。鉴于上述支持证据表明BBB渗透性，神经炎症中较高的结合以及与COX-2的特异性结合，[18F] MTP将与两个备用配体2和3一起进一步评估（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）（图2）将使用其他小鼠模型的神经炎症及伴有神经疗法的小鼠模型中的其他PET成像。确定的最合格的示踪剂将进行重新测试的动态PET定量评估，并在男性和女性麻醉猴子中与动脉血样同时进行，以将各种大脑区域的总分布量化为总分布量（AIM 3）。我们认为，提出的实验将导致选择成功的[18F] -COX-2 PET示踪剂，其特征是过渡到AD的临床研究，以早期诊断，监测治疗反应和帮助开发新药物。