Choroid plexus-mediated gene therapy for lysosomal storage disorders

脉络丛导向基因治疗溶酶体贮积性疾病。 脉络丛是高度血管化的结构，投射到脑室。除了创建血-脑脊液屏障外，脉络丛的极化上皮细胞还通过将水和离子从血液输送到脑室并分泌大量蛋白质来产生脑脊液。一些神经代谢疾病，如溶酶体储存障碍，可以从脉络丛靶向基因治疗方法中受益，因为脑脊液流动将分子从脑室系统携带到蛛网膜下腔，覆盖整个大脑表面。在外部研究人员(P.Dickson，UCLA和J.Wolfe，UPenn)的合作下，我们开始研究脉络丛导向的基因治疗IIIB型粘多糖病(Sanfilippo B综合征)，这是一种由N-乙酰氨基葡萄糖苷酶(NAGLU)缺乏引起的破坏性神经疾病，以及α-甘露糖苷症，这种罕见的疾病的特征是溶糖体α-甘露糖苷酶缺乏，由Laman基因突变引起。鞘内注射重组酶(在脊椎抽液时向脑脊液中注入酶)已在动物模型和溶酶体储存疾病的一些临床试验中获得成功。然而，这种方法的一个主要缺点是需要重复(例如，每月)鞘内注射。另一种不需要重复注射酶的给药途径是用含有目的酶基因的AAV载体转导脉络丛上皮细胞。重组AAV转导导致持续的外体转基因表达，脑脊液流动携带分子穿过脑室系统进入蛛网膜下腔，分子从那里最终到达整个大脑。我们正在研究两种已知的AAV血清型(AAV5和AAV4)的疗效，以及正在开发的新型脉络丛特异性AAV衣壳(见上文#1)。这些合作研究得到了国家MPS协会的外部资助，以及NIH床边和U01项目的支持。

Choroid plexus-directed gene therapy for lysosomal storage diseases. The choroid plexuses are highly vascularized structures that project into the ventricles of the brain. Besides creating the blood-CSF barrier, the polarized epithelia of the choroid plexus produce CSF by transporting water and ions into the ventricles from the blood and secreting a large number of proteins. A number of neurometabolic diseases, such as lysosomal storage disorders, could benefit from a choroid plexus-targeted gene therapy approach, since CSF flow carries molecules throughout the ventricular system into the subarachnoid space, which covers the entire brain surface.In collaboration with extramural investigators (P. Dickson, UCLA and J. Wolfe, UPenn), we embarked on investigations of choroid plexus-directed gene therapy for mucopolysaccharidosis type IIIB (Sanfilippo B syndrome), a devastating neurological disorder caused by N-acetylglucosaminidase (NAGLU) deficiency, and alpha-mannosidosis, a rare condition characterized by deficiency of the enzyme lysosomal acid alpha-mannosidase and caused by mutations of the LAMAN gene. Intrathecal delivery of recombinant enzyme (injecting enzyme into the cerebrospinal fluid during a spinal tap) has been successful in animal models and some clinical trials of lysosomal storage diseases. However, a major drawback to this approach is the need for repeated (e.g., monthly) intrathecal injections. An alternative route of administration without need for repeated enzyme injections would be transduction of choroid plexus epithelial cells with an AAV vector containing the cDNA for the enzyme of interest. Recombinant AAV transduction results in sustained episomal transgene expression, and CSF flow carries molecules throughout the ventricular system into the subarachnoid space from which molecules ultimately reach the entire brain. We are studying the efficacy of two known AAV serotypes (AAV5 and AAV4), as well as the novel choroid plexus-specific AAV capsid under development (see #1 above). These collaborative studies have supported by external grants from the National MPS Society, and the NIH Bench-to-Bedside and U01 programs.