Preclinical evaluation of tacrolimus in a canine model of Alzheimer's disease

项目摘要/摘要 我们建议的项目是检验这样一种假设，即抑制钙调神经磷酸酶(CN)可能是一种有希望的干预措施 预防或减缓阿尔茨海默病(AD)。我们治疗策略的分子靶点CN已经成为一种 与AD病理生理学相关的关键机制。中枢神经系统过度活动的迹象在早期阶段被发现。 人类和阿尔茨海默病小鼠模型的认知能力下降。在众多实验室进行的研究，使用了各种 的实验模型表明，CN活性对关键AD的进展既是必要的，也是充分的 标记物包括Aβ沉积，神经变性，神经炎症/神经胶质激活，突触功能障碍， 和认知能力丧失。为了抑制CN，我们将使用两种治疗方法：1)FDA批准的药物他克莫司，用于 同种异体移植排斥反应的预防和多种免疫/炎症性疾病的二线治疗； 2)Q134R，一种新型的羟基喹啉衍生物，它抑制CN依赖的转录因子NFAT(BUT 不抑制CN活性)。在啮齿动物模型中，他克莫司和Q134R显示出抗炎和 神经保护特性。此外，一项流行病学研究发现，痴呆症的发病率是 与年龄匹配的受试者相比，服用他克莫司的人肾移植患者显著减少 在普通人群中。 我们正在使用人类衰老和阿尔茨海默病的临床前犬模型。小猎犬在新陈代谢方面与人类相似 随着年龄的增长，自发性地发生淀粉样蛋白(Aβ，Aβ)沉积和认知能力下降。此外， 在几个备受瞩目的抗阿尔茨海默病药物试验中，老化的比格显示出预测的有效性。在这个项目中，我们 建议延长一项正在进行的纵向预防研究，该研究始于5-8岁的中年比格犬 正在接受他克莫司、Q134R或安慰剂治疗。在我们开始干预的年龄，大多数动物 认知完好无损，预计只有很少或没有大脑Aβ。狗已经接受了2.5年的治疗，并将 在这项新研究之前完成3年的治疗，我们建议将治疗研究延长到5年 总而言之。其中一组15只狗正在接受他克莫司(0.075 mg/kg/天)的治疗，第二组14只。 狗正在服用Q134R(每天8毫克)，其中一组作为安慰剂对照组(n=14)。目标1 将继续评估多种纵向认知结果，包括学习、执行功能、空间 和对象识别存储器。目标2将扩展AD生物标志物的血浆和脑脊液水平的测量 (例如，NFL、Aβ、GFAP)。AIM 3将继续进行结构、代谢和血管病理的MRI测量 检测反映大脑健康的体内结果。目标4将专注于神经病理学(Aβ，神经胶质细胞激活，突触 功能障碍、神经退行性变)和CN相关的途径修饰。这项研究中的所有结果衡量标准都是 与人类临床试验中使用的类似(如果不是相同的话)(包括人类MR扫描仪，流体生物标记物， 评估相似的认知域)。我们假设他克莫司和Q134R将导致 维持认知、维持脑脊液和反映脑功能减退的血浆生物标记物结果 病理、维持结构完整性、代谢功能降低和血管病理降低 AD神经病理学。这些研究将对AD的CN假说进行严格的检验，并可能为 研究CN抑制是否可作为人类AD的主要或补充治疗策略的方法 临床试验。

Project Summary/Abstract Our proposed project is to test the hypothesis that calcineurin (CN) inhibition may be a promising intervention to prevent or slow Alzheimer disease (AD). The molecular target of our treatment strategy, CN, has emerged as a key mechanism related to AD pathophysiology. Signs of CN hyperactivity are found during early stages of cognitive decline in humans and in mouse models of AD. Studies across numerous laboratories, using a variety of experimental models, suggest that CN activity is both necessary and sufficient for the progression of key AD markers including Aβ deposition, neurodegeneration, neuroinflammation/glial activation, synapse dysfunction, and cognitive loss. To inhibit CN, we will use two treatments: 1) tacrolimus, an FDA-approved drug used for the prophylaxis of allograft rejection and a second line treatment for numerous immune/inflammatory disorders and; 2) Q134R, a novel hydroxyquinoline derivative that inhibits the CN-dependent transcription factor, NFAT (but does not inhibit CN activity). In rodent models, tacrolimus and Q134R exhibit anti-inflammatory and neuroprotective properties. Moreover, an epidemiological study found that the incidence of dementia was strikingly reduced in human kidney transplant patients administered tacrolimus, relative to age-matched subjects in the general population. We are using the preclinical canine model of human aging and AD. Beagles are metabolically similar to humans and spontaneously develop amyloid-β (Aβ) deposition and cognitive decline with advanced age. Further, the aging beagle shows predictive validity in regard to several high-profile anti-AD drug trials. In this project, we proposed to extend an ongoing longitudinal prevention study, initiated in middle aged 5-8 year old beagles that are being treated with tacrolimus, Q134R or placebo. At the age we initiated the intervention, most animals were cognitively intact and expected to have little or no brain Aβ. Dogs have been treated for 2.5 years and will complete 3 years of treatment prior to this new study where we propose to extend the treatment study to 5 years in total. One group of 15 dogs is being treated with tacrolimus (0.075 mg/kg/day, orally), a second group of 14 dogs is receiving Q134R (8 mg/day orally) and one group is serving as a placebo control group (n=14). Aim 1 will continue to assess multiple longitudinal cognitive outcomes including learning, executive function, spatial and object recognition memory. Aim 2 will expand on measures of plasma and CSF levels of AD biomarkers (e.g. NfL, Aβ, GFAP). Aim 3 will continue MRI measures of structure, and metabolic and vascular pathology to detect in vivo outcomes reflecting brain health. Aim 4 will focus on neuropathology (Aβ, glial activation, synapse dysfunction, neurodegeneration) and CN related pathway modifications. All outcome measures in this study are similar if not identical to those used in human clinical trials (including a human MR scanner, fluid biomarkers, assessment of analogous cognitive domains). We hypothesize that tacrolimus and Q134R will lead to maintenance of cognition, maintenance of CSF and plasma biomarker outcomes reflecting reduced brain pathology, maintenance of structural integrity, metabolic function and reduced vascular pathology and reduced AD neuropathology. These studies will provide a rigorous test of the CN hypothesis of AD and possibly pave the way for investigating if CN inhibition may serve as a primary or complementary treatment strategy in human AD clinical trials.