High-Level Expression of Alkaline Phosphatase by Adeno-Associated Virus Vector Ameliorates Pathological Bone Structure in a Hypophosphatasia Mouse Model
High-Level Expression of Alkaline Phosphatase by Adeno-Associated Virus Vector Ameliorates Pathological Bone Structure in a Hypophosphatasia Mouse Model
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DOI：
10.1007/s00223-020-00676-5
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发表时间：
2020-02-19
影响因子：
4.2
通讯作者：
Kasahara, Masataka
中科院分区：
文献类型：
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作者：
Nakamura-Takahashi, Aki;Tanase, Toshiki;Kasahara, Masataka
低磷酸酶症（HPP）是一种由编码组织非特异性碱性磷酸酶（TNALP）的基因突变引起的全身性骨骼疾病。我们最近报道，HPP模型小鼠的生存期可以延长使用腺相关病毒（AAV）载体表达骨靶向TNALP与十-天冬氨酸在C端（TNALP-D-10），然而，异常的骨结构和低矿化仍然在治疗的小鼠。在这里，为了开发更有效和临床适用的方法，我们评估了以比以前使用的更高剂量用表达TNALP-D-10的病毒载体转染是否会改善骨结构缺损。我们构建了由鸡β-肌动蛋白（CBA）启动子驱动的表达TNALP的自身互补AAV 8载体（scAAV 8-CB-TNALP-D-10）。将载体以4.5 × 10（12）载体基因组（v.g.）/kg的剂量注射到新生HPP小鼠的两个股四头肌中。体，导致20 U/mL的血清ALP活性。4.5 x 10（12）v.g./身体治疗的HPP小鼠生长正常，并在X射线图像中显示膝关节处的骨结构改善。显微CT分析显示正常的骨小梁结构和矿化。股骨的力学性能也得到恢复。股骨的组织学分析表明，ALP替代水平足以促进正常的生长板软骨排列。这些结果表明，AAV载体介导的高剂量TNALP-D-10疗法是改善患有婴儿型HPP的患者的生活质量（QOL）的有希望的选择。
Hypophosphatasia (HPP) is a systemic skeletal disease caused by mutations in the gene encoding tissue-nonspecific alkaline phosphatase (TNALP). We recently reported that survival of HPP model mice can be prolonged using an adeno-associated virus (AAV) vector expressing bone-targeted TNALP with deca-aspartate at the C terminus (TNALP-D-10); however, abnormal bone structure and hypomineralization remained in the treated mice. Here, to develop a more effective and clinically applicable approach, we assessed whether transfection with TNALP-D-10 expressing virus vector at a higher dose than previously used would ameliorate bone structure defects. We constructed a self-complementary AAV8 vector expressing TNALP driven by the chicken beta-actin (CBA) promoter (scAAV8-CB-TNALP-D-10). The vector was injected into both quadriceps femoris muscles of newborn HPP mice at a dose of 4.5 x 10(12) vector genome (v.g.)/body, resulting in 20 U/mL of serum ALP activity. The 4.5 x 10(12) v.g./body-treated HPP mice grew normally and displayed improved bone structure at the knee joints in X-ray images. Micro-CT analysis showed normal trabecular bone structure and mineralization. The mechanical properties of the femur were also recovered. Histological analysis of the femurs demonstrated that ALP replacement levels were sufficient to promote normal, growth plate cartilage arrangement. These results suggest that AAV vector-mediated high-dose TNALP-D-10 therapy is a promising option for improving the quality of life (QOL) of patients with the infantile form of HPP.