Rescue of Severe Infantile Hypophosphatasia Mice by AAV-Mediated Sustained Expression of Soluble Alkaline Phosphatase
Rescue of Severe Infantile Hypophosphatasia Mice by AAV-Mediated Sustained Expression of Soluble Alkaline Phosphatase
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DOI：
10.1089/hum.2010.210
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发表时间：
2011-11-01
影响因子：
4.2
通讯作者：
Shimada, Takashi
中科院分区：
文献类型：
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作者：
Matsumoto, Tae;Miyake, Koichi;Shimada, Takashi
低磷症(HPP)是由组织非特异性碱性磷酸酶(TNALP)缺乏引起的一种遗传性疾病。人类HPP的主要症状是矿化不足、软骨病或软骨病，尽管临床严重程度差异很大。TNALP基因敲除(Akp2(-/-))小鼠的表型与严重的婴儿型HPP相似。Akp2(-/-)小鼠出生时看起来正常，但它们会出现生长障碍、癫痫发作和矿物质减少，并在20天大时死亡。以前，我们已经证明，可以通过骨靶向TNALP的酶替代来防止Akp2(-/-)小鼠的表型，其中十个天冬氨酸连接到可溶性TNALP的C末端(TNALP-D10)。在本研究中，我们评价了表达不同形式的TNALP的腺相关病毒血清8型(AAV8)载体的治疗效果，包括TNALP-D10、标记有标志表位的可溶性TNALP(TNALP-F)和天然糖基磷脂酰肌醇锚定的TNALP(TNALP-N)。一次静脉注射5×10(10)载体基因组AAV8-TNALP-D10于第1天进入Akp2(-/-)小鼠可延长小鼠的存活时间并纠正其表型。当AAV8-TNALP-F注射到新生Akp2(-/-)小鼠体内时，它们也存活了下来，没有癫痫发作。有趣的是，在AAV8-TNALP-N治疗的一些动物中观察到了存活效果。所有存活的Akp2(-/-)小鼠在X射线上均表现出健康的外观和正常的活动，并有成熟的骨矿化。这些结果表明，血浆中持续的碱性磷酸酶活性对于拯救Akp2(-/-)小鼠是必要的和充分的。AAV8介导的系统基因治疗似乎是治疗婴儿型人类HPP的有效方法。
Hypophosphatasia (HPP) is an inherited disease caused by a deficiency of tissue-nonspecific alkaline phosphatase (TNALP). The major symptom of human HPP is hypomineralization, rickets, or osteomalacia, although the clinical severity is highly variable. The phenotypes of TNALP knockout (Akp2(-/-)) mice mimic those of the severe infantile form of HPP. Akp2(-/-) mice appear normal at birth, but they develop growth failure, epileptic seizures, and hypomineralization and die by 20 days of age. Previously, we have shown that the phenotype of Akp2(-/-) mice can be prevented by enzyme replacement of bone-targeted TNALP in which deca-aspartates are linked to the C-terminus of soluble TNALP (TNALP-D10). In the present study, we evaluated the therapeutic effects of adeno-associated virus serotype 8 (AAV8) vectors that express various forms of TNALP, including TNALP-D10, soluble TNALP tagged with the Flag epitopes (TNALP-F), and native glycosylphosphatidylinositol-anchored TNALP (TNALP-N). A single intravenous injection of 5 x 10(10) vector genomes of AAV8-TNALP-D10 into Akp2(-/-) mice at day 1 resulted in prolonged survival and phenotypic correction. When AAV8-TNALP-F was injected into neonatal Akp2(-/-) mice, they also survived without epileptic seizures. Interestingly, survival effects were observed in some animals treated with AAV8-TNALP-N. All surviving Akp2(-/-) mice showed a healthy appearance and a normal activity with mature bone mineralization on X-rays. These results suggest that sustained alkaline phosphatase activity in plasma is essential and sufficient for the rescue of Akp2(-/-) mice. AAV8-mediated systemic gene therapy appears to be an effective treatment for the infantile form of human HPP.