Pyrimethamine as a potential pharmacological chaperone for late-onset forms of GM2 gangliosidosis
Pyrimethamine as a potential pharmacological chaperone for late-onset forms of GM2 gangliosidosis
复制标题
DOI：
10.1074/jbc.m609304200
复制
发表时间：
2007-03-23
影响因子：
4.8
通讯作者：
Mahuran, Don J.
中科院分区：
文献类型：
--
作者：
Maegawa, Gustavo H. B.;Tropak, Michael;Mahuran, Don J.
迟发性GM 2神经节苷脂沉积症由两种相关的常染色体隐性遗传神经退行性疾病组成，均由溶酶体异二聚体β-氨基己糖苷酶A（Hex A，α β）缺乏引起。药理学伴侣（PC）是一种小分子，可以稳定突变蛋白的构象，使其能够通过内质网的质量控制系统。迄今为止，所有成功的PC也都是竞争性抑制剂。在1040种食品药品监督管理局批准的化合物的库中筛选Hex A抑制剂，确定乙胺嘧啶（PYR（2，4-二氨基5-（4-氯苯基）-6-乙基嘧啶））为最有效的抑制剂。将来自10名迟发性泰-萨二氏病（11个α-突变，2个新的）和7名桑德霍夫病（9个β-突变，4个新的）患者的细胞系与对应于治疗剂量的浓度的PYR一起培养。携带最常见的晚发型突变α G269 S的细胞显示残留Hex A活性显著增加，测试的所有7种β突变体也是如此。响应PC处理的细胞包括携带导致Hex热稳定性降低的突变体和固有不太稳定的α亚基的部分剪接点突变的那些细胞。PYR，结合到域II中的活性位点，能够作为PC甚至对域I β-突变体起作用。我们的结论是PYR作为一种突变特异性PC发挥作用，它能增强迟发性GM 2神经节苷脂沉积症患者细胞中残留的溶酶体Hex A水平。
Late-onset GM2 gangliosidosis is composed of two related, autosomal recessive, neurodegenerative diseases, both resulting from deficiency of lysosomal, heterodimeric beta-hexosaminidase A (Hex A, alpha beta). Pharmacological chaperones (PC) are small molecules that can stabilize the conformation of a mutant protein, allowing it to pass the quality control system of the endoplasmic reticulum. To date all successful PCs have also been competitive inhibitors. Screening for Hex A inhibitors in a library of 1040 Food Drug Administration-approved compounds identified pyrimethamine (PYR (2,4-diamino 5-(4-chlorophenyl)-6-ethylpyrimidine)) as the most potent inhibitor. Cell lines from 10 late-onset Tay-Sachs (11 a-mutations, 2 novel) and 7 Sandhoff (9 beta-mutations, 4 novel) disease patients, were cultured with PYR at concentrations corresponding to therapeutic doses. Cells carrying the most common late-onset mutation, alpha G269S, showed significant increases in residual Hex A activity, as did all 7 of the beta-mutants tested. Cells responding to PC treatment included those carrying mutants resulting in reduced Hex heat stability and partial splice junction mutations of the inherently less stable a-subunit. PYR, which binds to the active site in domain II, was able to function as PC even to domain I beta-mutants. We concluded that PYR functions as a mutation-specific PC, variably enhancing residual lysosomal Hex A levels in late-onset GM2 gangliosidosis patient cells.