Medin J A, Tudor M, Simovitch R, Quirk J M, Jacobson S, Murray G J, Brady R O
Developmental and Metabolic Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Proc Natl Acad Sci U S A. 1996 Jul 23;93(15):7917-22. doi: 10.1073/pnas.93.15.7917.
Fabry disease is an X-linked metabolic disorder due to a deficiency of alpha-galactosidase A (alpha-gal A; EC 3.2.1.22). Patients accumulate glycosphingolipids with terminal alpha-galactosyl residues that come from intracellular synthesis, circulating metabolites, or from the biodegradation Of senescent cells. Patients eventually succumb to renal, cardio-, or cerebrovascular disease. No specific therapy exists. One possible approach to ameliorating this disorder is to target corrective gene transfer therapy to circulating hematopoietic cells. Toward this end, an amphotropic virus-producer cell line has been developed that produces a high titer (>10(6) i.p. per ml) recombinant retrovirus constructed to transduce and correct target cells. Virus-producer cells also demonstrate expression of large amounts of both intracellular and secreted alpha-gal A. To examine the utility of this therapeutic vector, skin fibroblasts from Fabry patients were corrected for the metabolic defect by infection with this recombinant virus and secreted enzyme was observed. Furthermore, the secreted enzyme was found to be taken up by uncorrected cells in a mannose-6-phosphate receptor-dependent manner. In related experiments, immortalized B cell lines from Fabry patients, created as a hematologic delivery test system, were transduced. As with the fibroblasts, transduced patient B cell lines demonstrated both endogenous enzyme correction and a small amount of secretion together with uptake by uncorrected cells. These studies demonstrate that endogenous metabolic correction in transduced cells, combined with secretion, may provide a continuous source of corrective material in trans to unmodified patient bystander cells (metabolic cooperativity).
法布里病是一种X连锁代谢紊乱疾病，由α-半乳糖苷酶A（α-gal A；EC 3.2.1.22）缺乏所致。患者体内蓄积带有末端α-半乳糖基残基的糖鞘脂，这些糖鞘脂来源于细胞内合成、循环代谢产物或衰老细胞的生物降解。患者最终会死于肾脏、心脏或脑血管疾病。目前尚无特效疗法。改善这种疾病的一种可能方法是将矫正基因转移疗法靶向循环造血细胞。为此，已开发出一种嗜异性病毒生产细胞系，该细胞系可产生高滴度（每毫升腹腔注射>10⁶）的重组逆转录病毒，构建该病毒的目的是转导并矫正靶细胞。病毒生产细胞还显示出大量细胞内和分泌型α-gal A的表达。为了检验这种治疗载体的效用，用这种重组病毒感染法布里病患者的皮肤成纤维细胞，矫正其代谢缺陷，并观察到分泌型酶。此外，发现分泌型酶以依赖甘露糖-6-磷酸受体的方式被未矫正的细胞摄取。在相关实验中，转导了作为血液输送测试系统构建的法布里病患者永生化B细胞系。与成纤维细胞一样，转导后的患者B细胞系既显示出内源性酶的矫正，又有少量分泌，同时未矫正的细胞会摄取这些分泌物。这些研究表明，转导细胞中的内源性代谢矫正与分泌相结合，可能会为未修饰的患者旁观者细胞（代谢协同作用）提供持续的矫正物质来源。
