Transgene produces massive overexpression of human β-glucuronidase in mice, lysosomal storage of enzyme, and strain-dependent tumors
Transgene produces massive overexpression of human β-glucuronidase in mice, lysosomal storage of enzyme, and strain-dependent tumors
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DOI：
10.1073/pnas.0437941100
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发表时间：
2003-03-04
影响因子：
11.1
通讯作者：
Sly, WS
中科院分区：
文献类型：
--
作者：
Vogler, C;Galvin, N;Sly, WS
β-葡糖醛酸酶（GUSB）是一种在糖胺聚糖的正常逐步降解中重要的溶酶体酶。GUSB缺乏导致溶酶体贮积病粘多糖沉积症VII（MPS VII，Sly病）。受影响的患者在溶酶体中广泛进行性蓄积含β-葡糖苷酸的糖胺聚糖。酶替代、骨髓移植和基因治疗可纠正MPS VII小鼠模型中的溶酶体贮积。在MPS VII患者和动物中的基因治疗可能导致GUSB在个体组织中的大量过表达，并且这种过表达的毒性尚未完全研究。为了深入了解GUSB大量过表达的影响，我们建立了19个转基因小鼠品系，其中两个在许多组织中表达非常高水平的人GUSB。创始人过度表达小鼠的组织和血清GUSB增加>100至数千倍。在一个品系的后代中，大多数组织中的酶表达下降，在另一个品系的后代中，肝脏和骨髓中的酶表达下降。这两个系具有形态学上相似的广泛的GUSB溶酶体储存和其他溶酶体酶的继发性升高，这是溶酶体储存病的特征。一个细胞系发生了肿瘤，另一个没有。这些转基因模型表明，溶酶体酶的大量过表达可能与戏剧性的形态学改变，其中，至少在两个线之一，几乎没有临床后果。对于另一个转基因系，F-2 FVB子代中肿瘤发展的高频率表明用于产生转基因系的载体具有整合位点依赖性致癌潜力，至少在该菌株背景中是如此。
betawGlucuronidase (GUSB) is a lysosomal enzyme important in the normal step-wise degradation of glycosaminoglycans. Deficiency of GUSB causes the lysosomal storage disease mucopolysaccharidosis VII (MPS VII, Sly disease). Affected patients have widespread progressive accumulation of beta-glucuronide-containing glycosaminoglycans in lysosomes. Enzyme replacement, bone marrow transplantation, and gene therapy can correct lysosomal storage in the MPS VII mouse model. Gene therapy in MPS VII patients and animals may result in massive overexpression of GUSB in individual tissues, and the toxicity of such overexpression is incompletely investigated. To gain insight into the effect of massive overexpression of GUSB, we established 19 transgenic mouse lines, two of which expressed very high levels of human GUSB in many tissues. The founder overexpressing mice had from >100- to several thousand-fold increases in tissue and serum GUSB. The enzyme expression in most tissues decreased in subsequent generations in one line, and expression in liver and marrow fell in subsequent generations of the other. Both lines had morphologically similar widespread lysosomal storage of GUSB and secondary elevations of other lysosomal enzymes, a finding characteristic of lysosomal storage disease. One line developed tumors, and one did not. These transgenic models show that massive overexpression of a lysosomal enzyme can be associated with dramatic morphological alterations, which, at least in one of the two lines, had little clinical consequence. For the other transgenic line, the high frequency of tumor development in F-2 FVB progeny suggests that the vector used to generate the transgenic lines has an integration site-dependent potential to be oncogenic, at least in this strain background.