Sakuraba Hitoshi, Tsukimura Takahiro, Shiga Tomoko, Saito Seiji, Tajima Youichi, Kawashima Ikuo, Fukushige Tomoko, Togawa Tadayasu
Department of Clinical Genetics, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan.
Department of Functional Bioanalysis, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan.
Mol Genet Metab. 2025 Aug;145(4):109151. doi: 10.1016/j.ymgme.2025.109151. Epub 2025 May 26.
Enzyme replacement therapy (ERT) using recombinant human α-galactosidase A (AGAL) is a standard therapy for Fabry disease. However, systemic reviews have reported that recurrent injection of the enzyme can induce the formation of harmful antidrug antibodies (ADAs) in male patients with Fabry disease. Unfortunately, to date no recommended ERT drugs facilitating escape from ADA formation have yet been established. Accordingly, we focused on α-N-acetylgalactosaminidase (NAGA), which has a protein structure that is similar to that of AGAL. Previously, we had prepared a modified NAGA (p. S188E and p. A191L) and determined the biochemical properties of the new enzyme. In this study we verified the efficacy of the modified NAGA, both in silico and via cell and animal experiments. The molecular dynamics simulation results suggested that the enzyme has an affinity for α-D-galactose (α-Gal) as a ligand. Moreover, these results also suggested that the modified NAGA may hydrolyze the terminal α-Gal moieties of glycoconjugates. The cell experiments revealed that the modified NAGA incorporated into cultured Fabry fibroblasts was more stable than recombinant human AGAL, despite the specific enzyme activity of the former being lower than that of the latter. Additional animal experiments revealed that human NAGA-transgenic/Gla-knockout mice were tolerant of recurrent administration of the modified NAGA, and that the modified NAGA notably did not induce the formation of ADAs. Moreover, the enzyme also suppressed the progressive accumulation of globotriaosylceramide and globotriaosylsphingosine in organs/tissues, thereby improving morphological changes in young mice. Overall, these findings suggest that the modified NAGA is a promising ERT drug candidate for patients with Fabry disease, especially for those who are likely to produce anti-AGAL antibodies.
使用重组人α-半乳糖苷酶A（AGAL）的酶替代疗法（ERT）是法布里病的标准疗法。然而，系统评价报告称，反复注射该酶可诱导法布里病男性患者产生有害的抗药物抗体（ADA）。不幸的是，迄今为止尚未确立推荐的有助于避免ADA形成的ERT药物。因此，我们聚焦于α-N-乙酰半乳糖胺酶（NAGA），其蛋白质结构与AGAL相似。此前，我们制备了一种修饰的NAGA（p.S188E和p.A191L）并确定了新酶的生化特性。在本研究中，我们通过计算机模拟以及细胞和动物实验验证了修饰的NAGA的疗效。分子动力学模拟结果表明，该酶对作为配体的α-D-半乳糖（α-Gal）具有亲和力。此外，这些结果还表明，修饰的NAGA可能水解糖缀合物的末端α-Gal部分。细胞实验表明，尽管修饰的NAGA的比酶活性低于重组人AGAL，但掺入培养的法布里成纤维细胞中的修饰的NAGA更稳定。额外的动物实验表明，人NAGA转基因/Gla基因敲除小鼠对反复给予修饰的NAGA具有耐受性，并且修饰的NAGA明显不会诱导ADA的形成。此外，该酶还抑制了球三糖神经酰胺和球三糖鞘氨醇在器官/组织中的渐进性积累，从而改善了幼鼠的形态学变化。总体而言，这些发现表明，修饰的NAGA是法布里病患者，尤其是那些可能产生抗AGAL抗体的患者的一种有前景的ERT候选药物。
