Real-Time Tracking of Gene Therapy by Bioactivated MR contrast Probes

翻译后摘要：实时跟踪基因治疗的生物激活磁共振造影剂探针 平均存活率为5年（大多数病例是致命的），溶酶体贮积病（LSD）是其中之一。 医学界最糟糕的预后LSD代表了大量的单基因疾病， 血友病的患病率很低。作为具有明确定义的基因型-表型的单基因疾病， 关系，溶酶体贮积病是基因治疗的极好候选者。变革性成果 在一项腺相关病毒（AAV）基因治疗脊髓灰质炎患儿的临床试验中， 肌肉萎缩明确地证明了体内基因转移治疗单基因 神经紊乱 然而，到目前为止，缺乏非侵入性的方法来确定这些生物分布或活性水平。 患者中的AAV疗法。这是一个重大的障碍，让调查人员猜测哪些器官或 有效地治疗结构，并且由于与临床疾病进展相关的滞后时间， 这种限制最终会影响治疗方式的演变。 为了克服这些局限性，我们提出发展一种新的磁共振成像 （MRI）为基础的技术来跟踪酶活性在任何器官，外周神经系统（PNS），或中枢 神经系统（CNS）随着时间的推移，因此有可能适用于任何LSD引起的 酶缺乏症磁共振成像是研究神经系统的理想技术 紊乱这种技术已经成为诊断放射学的金标准，因为缺乏 这种成像设备能够进行电离辐射，并且能够进行真正的3D成像，并且已经使用了几十年。详细 结构信息可以在几分钟内获得，单个切片可以在几秒钟内获得。然而，需要 区分磁性相似但组织学上不同的组织或器官的区域一直是一种有效的方法。 是造影增强剂发展的主要动力。超过40%的MR手术 使用造影剂，迄今为止已经向患者施用了超过450，000万剂， Gd（III）造影剂是目前使用的最安全的临床探头之一。 我们率先开发了生物响应（即，条件激活的）MR造影剂， 自从这类探针文库从酶激活剂扩展到pH敏感性， 离子如Zn（II）和Ca（II）的检测，以及氧化还原活化。在这里，我们描述了一个 平台，其中底物（防止水接近Gd（III）离子）被酶去除， 可以被替换以适应许多基因治疗靶点。

Abstract: Real-Time Tracking of Gene Therapy by Bioactivated MR contrast Probes With mean survival rate of 5 years (and most cases are fatal) lysomal storage diseases (LSD) are among the most dismal of prognosis in all of medicine. LSD's represent a large number of monogenetic diseases and while rare the prevalence is to hemophilia. As monogenetic diseases with clearly defined genotype-phenotype relations, lysosomal storage diseases are excellent candidates for gene therapy. The transformative results documented in an adeno-associated virus (AAV) gene therapy clinical trial in infants affected by spinal muscular atrophy demonstrated unequivocally the potential of in vivo gene transfer to treat monogenic neurological disorder. However, to date, there is a lack of non-invasive ways to determine biodistribution or activity levels of these AAV therapies in patients. This is a significant hinderance, leaving investigators guessing which organs or structures are effectively treated and, due to the lag time associated with clinical disease progression, this limitation ultimately impacts the evolution of treatment modalities. In order to overcome these limitations, we propose the development of a new magnetic resonance imaging (MRI)-based technology to track enzymatic activity in any organ, peripheral nervous system (PNS), or central nervous system (CNS) over time and thus have the potential to be applicable to any LSD caused by an enzymatic deficiency. Magnetic resonance imaging is an ideal technique for the study of neurological disorders. This technique is has become a gold standard in diagnostic radiology as a result of the absence of ionizing radiation and is capable of true 3D imaging and has been in use for several decades . Detailed structural information can be obtained in minutes, and single slices in seconds. However, the need to differentiate regions of tissues or organs that are magnetically similar but histologically distinct has been a major impetus for the development of contrast enhancement agents. Greater than 40% of all MR procedures employ contrast agents with more than 450,000 million doses to date have been administered to patients and Gd(III) based contrast agents are among the safest clinical probes in use. We pioneered the development of bio-responsive (i.e., conditionally activated) MR contrast agents and since that time a library of this class of probes has expanded from enzyme activated agents to pH sensitive, the detection of ions such as Zn(II) and Ca(II), and redox activated. Here, we describe the development of a platform where the substrate (that prevents access of water to a Gd(III) ion) is removed by an enzyme which can be substituted to accommodate a number of gene therapy targets.