Institute of Metabolic Disease, Baylor Research Institute, Dallas, Texas, USA.
Mol Ther Nucleic Acids. 2013 Oct 22;2(10):e130. doi: 10.1038/mtna.2013.57.
Krabbe disease is a devastating neurodegenerative lysosomal storage disorder caused by a deficiency of β-galactocerebrosidase (GALC). Gene therapy is a promising therapeutic approach for Krabbe disease. As the human brain is large and it is difficult to achieve global gene transduction, the efficacy of cross-correction is a critical determinant of the outcome of gene therapy for this disease. We investigated whether HIV Tat protein transduction domain (PTD) can improve the cross-correction of GALC. Tat-PTD significantly increased (~6-fold) cross-correction of GALC through enhanced secretion and uptake in a cell-culture model system. The effects of Tat-PTD were gene and flanking amino acids dependent. Tat-fusion increased the secretion of α-galactosidase A (α-gal A), but this did not improve its cross-correction. Tat-fusion did not change either secretion or uptake of β-glucocerebrosidase (GC). Tat-PTD increased GALC protein synthesis, abolished reactivity of GC to the 8E4 antibody, and likely reduced mannose phosphorylation in all these lysosomal enzymes. This study demonstrated that Tat-PTD can be useful for increasing cross-correction efficiency of lysosomal enzymes. However, Tat-PTD is not a mere adhesive motif but possesses a variety of biological functions. Therefore, the potential beneficial effect of Tat-PTD should be assessed individually on each lysosomal enzyme.Molecular Therapy-Nucleic Acids (2013) 2, e130; doi:10.1038/mtna.2013.57; published online 22 October 2013.
克拉伯病是一种破坏性的神经退行性溶酶体贮积症，由β-半乳糖脑苷脂酶（GALC）缺乏引起。基因治疗是克拉伯病的一种有前途的治疗方法。由于人脑较大，难以实现全局基因转导，因此交叉校正的效果是该疾病基因治疗结果的关键决定因素。我们研究了 HIV Tat 蛋白转导结构域（PTD）是否可以改善 GALC 的交叉校正。在细胞培养模型系统中，Tat-PTD 通过增强分泌和摄取，显著增加了 GALC 的交叉校正（~6 倍）。Tat-PTD 的作用取决于基因和侧翼氨基酸。Tat 融合增加了α-半乳糖苷酶 A（α-gal A）的分泌，但这并没有改善其交叉校正。Tat 融合既没有改变β-葡糖苷脑苷脂酶（GC）的分泌也没有改变其摄取。Tat-PTD 增加了 GALC 蛋白合成，使 GC 对 8E4 抗体失去反应性，并可能降低所有这些溶酶体酶中的甘露糖磷酸化。这项研究表明，Tat-PTD 可用于提高溶酶体酶的交叉校正效率。然而，Tat-PTD 不仅仅是一个粘附基序，而是具有多种生物学功能。因此，应该单独评估 Tat-PTD 对每种溶酶体酶的潜在有益作用。分子治疗-核酸（2013 年）2，e130；doi:10.1038/mtna.2013.57；2013 年 10 月 22 日在线发表。
