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

描述(申请人提供)：问题所在。HIV相关的严重神经病理和高效抗逆转录病毒疗法(HAART)的神经副作用最近被确定为慢性艾滋病治疗的主要危险因素。核苷类逆转录酶抑制剂(NRTI)是HAART的重要组成部分，在长期的治疗过程中，由于外周和中枢神经系统神经元线粒体功能的退化而导致神经毒性。由于血脑屏障(BBB)阻止药物在脑内达到治疗水平，位于中枢神经系统吞噬细胞中的HIV-1的治疗效果远不理想，HIV相关的炎症过程对神经元的活性产生负面影响，并导致HIV诱导的脑炎(HIVE)和痴呆的发生。开发神经毒性降低的新型NRTI药物形式和有效地将其输送到中枢神经系统的特殊方法是这项赠款申请的主要目标。假设。作为一种有效的药物形式，磷酸化ntri(PNRTI)与目前可用的NRTI相比，将是毒性更低、治疗HIV-1感染更有效的药物。PNRTI的主要优势是：(1)在受感染的宿主细胞(巨噬细胞、星形胶质细胞、胶质细胞)中有更高的抗HIV-1效力，这些细胞缺乏激酶活性或对抗耐药病毒形式，(2)限制pNRTI进入线粒体(较低的线粒体毒性)，以及(3)限制带负电荷的pNRTI(减少非特异性毒性)。由于大多数pNRTI在体内是不稳定的，我们推测，将pNRTI包裹在经过血脑屏障的药物传递优化的纳米载体中，将提供有效的药物进入携带HIV-1的外周或脑内吞噬细胞。我们已经开发了新型稳定的药物纳米制剂(Nano-NRTI)，它可以比NRTI更有效地抑制病毒在巨噬细胞中的复制，并且在其他组织中蓄积的机会更低，并产生非特异性毒性。为了提高纳米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多肽或多胺进行修饰。然后，纳米NRTI将穿过血脑屏障内皮细胞，在脑实质和脑内巨噬细胞中释放激活的pNRTI。针对这一假设，我们提出了以下具体目标：(1)应用合理的药物设计和纳米工程技术构建携带pNRTI的纳米载体；(2)优化纳米-NRTI在体外培养的巨噬细胞、脑血管内皮细胞和神经元中的抗病毒作用和低细胞毒性；(3)提高Nano-NRTI跨越血脑屏障并在脑内蓄积的效率；(4)评价Nano-NRTI治疗对蜂房小鼠神经病理的影响。意义和影响。神经毒性较低的HAART可能来自对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(Nano-HAART)，它能够在降低神经毒性的情况下将脑靶向和口服激活药物制剂输送到中枢神经系统。

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.