CNS Delivery of Activated Antiviral Drugs with Reduced Neurotoxicity (Nano-NRTIs)

描述（由申请人提供）：问题。严重的hiv相关神经病理和高效抗逆转录病毒治疗（HAART）的神经系统副作用最近被确定为慢性艾滋病治疗的主要危害。HAART的重要成分核苷类逆转录酶抑制剂（NRTI）在长期治疗过程中由于外周和中枢神经系统神经元线粒体功能的退化而诱导神经毒性。由于血脑屏障（BBB）阻止药物在大脑中达到治疗水平，因此对位于中枢神经系统吞噬细胞中的HIV-1的治疗远不能令人满意，因此hiv相关的炎症过程对神经元的活力产生负面影响，并导致hiv诱导的脑炎（HIVE）和痴呆的发展。开发具有降低神经毒性的新型NRTI药物形式和有效递送到中枢神经系统的特殊方法是本资助申请的主要目标。假设。磷酸化的NTRI （pNRTI）作为一种活性药物形式，与目前可用的NRTI相比，其毒性更小，治疗HIV-1感染的效率更高。pNRTI的主要优势，将说明我们的选择，如下：(1)在受感染的宿主细胞（巨噬细胞，星形胶质细胞，胶质细胞）激酶活性缺乏或耐药病毒形式中对HIV-1具有更高的功效，(2)限制pNRTI进入线粒体（降低线粒体毒性），(3)限制带负电荷的pNRTI的细胞积累（减少非特异性毒性）。由于大多数pNRTI在体内是不稳定的，我们假设将pNRTI包封在纳米载体中，通过血脑屏障优化药物递送，将为携带hiv -1的外周或脑内吞噬细胞提供有效的药物通路。我们开发了新型稳定的纳米药物（Nano-NRTI），它可以比NRTI更有效地抑制巨噬细胞中的病毒增殖，并且在其他组织中积累的机会更低，产生非特异性毒性。为了增强纳米nrti在给药后与血脑屏障结合的协同性，建议使用脑受体特异性肽或多胺进行修饰。纳米nrti随后穿过血脑屏障内皮，在脑实质和脑内巨噬细胞中释放活化的pNRTI。针对这一假设，我们提出了以下具体目标：(1)将合理的药物设计和纳米工程应用于pNRTI纳米载体的构建；(2)优化纳米nrti对体外培养巨噬细胞、脑血管内皮细胞和神经元的抗病毒作用和低细胞毒性；(3)提高纳米nrti穿过血脑屏障并在脑内蓄积的效率；(4)评价纳米nrti对HIVE模型小鼠神经病理学的影响。意义和影响。低神经毒性的HAART版本可能来自合理药物设计和靶向给药的研究。我们开发了一种基于pnrti的HAART设计（纳米HAART），它可以将脑靶向和口服活化药物配方以降低神经毒性递送到中枢神经系统。

DESCRIPTION (provided by applicant): The problem. Serious HIV-associated neuropathology and the neurological side effects of Highly Active Antiretroviral Therapy (HAART) have been recently identified as the major hazards of chronic AIDS treatment. The important components of HAART, nucleoside reverse transcriptase inhibitors (NRTI), induce neurotoxicity due to the degradation of mitochondrial functions in peripheral and CNS neurons during long-term therapy. Since the treatment of HIV-1 located in phagocytic cells in CNS is far from satisfactory due to the blood-brain barrier (BBB) preventing drugs from reaching therapeutic levels in the brain, HIV-associated inflammatory processes make a negative impact on the viability of neurons and result in the development of HIV-induced encephalitis (HIVE) and dementia. The development of novel NRTI drug forms with reduced neurotoxicity and special approaches to their efficient delivery to the CNS is the major goal of this grant application. Hypothesis. Phosphorylated NTRI (pNRTI), as an active drug form, would be less toxic and more efficient drugs for the treatment of HIV-1 infection than the currently available NRTI. The major advantages of pNRTI, which will illustrate our choice, are as follows: (1) potential higher efficacy against HIV-1 in the infected host cells (macrophages, astrocytes, glial cells) deficient by kinase activities or against drug-resistant virus forms, (2) limited pNRTI access in mitochondria (lower mitochondrial toxicity), and (3) restricted cellular accumulation of negatively-charged pNRTI (reduced nonspecific toxicity). Since the majority of pNRTI are unstable in vivo, we hypothesize that the encapsulation of pNRTI in nanocarriers optimized for drug delivery across the BBB would provide efficient drug access to HIV-1-bearing peripheral or brain-harboring phagocytes. We have developed novel stable drug nanoformulations (Nano-NRTI), which can suppress virus multiplication more effectively than NRTI in macrophages and have a lower chance of accumulating in other tissues and exerting nonspecific toxicities. Modification with brain receptor-specific peptides or polyamines is proposed in order to enhance the cooperativity of Nano-NRTI binding with the BBB following drug administration. Nano-NRTI would then cross the BBB endothelium and release activated pNRTI in the brain parenchyma and brain-harboring macrophages. To address this hypothesis, we propose the following Specific aims: (1) to apply rational drug design and nanoengineering to the construction of nanocarriers loaded with pNRTI; (2) to optimize the antiviral effect and low cytotoxicity of Nano-NRTI in cultured macrophages, brain vascular endothelial cells, and neurons in vitro; (3) to enhance the efficiency of Nano-NRTI to cross the blood-brain barrier and accumulate in the brain; (4) to evaluate the effects of Nano-NRTI treatment on neuropathology in a mouse model of HIVE. Significance and impact. The less-neurotoxic version of HAART is likely to come from studies on rational drug design and targeted delivery. We develop a pNRTI-based HAART design (Nano-HAART), which enables the delivery of brain-targeted and oral activated drug formulations with reduced neurotoxicity into the CNS.