Department of Pediatrics, Medical University of Graz, Graz, Austria.
J Inherit Metab Dis. 2012 May;35(3):495-503. doi: 10.1007/s10545-011-9409-2. Epub 2011 Oct 28.
Unlike replacement therapy by infusion of exogenous recombinant lysosomal enzymes, pharmacological chaperones aim at a gain of function of endogenous gene products. Deficits resulting from missense mutations may become treatable by small, competitive inhibitors binding to the catalytical site and thus correcting the erroneous conformation of mutant enzymes. This may prevent their premature degradation and normalize intracellular trafficking as well as biological half-life. A major limitation currently arises from the huge number of individual missense mutations and the lack of knowledge on the structural requirements for specific interaction with mutant protein domains. Our previous work on mutations of the β-galactosidase (β-gal) gene, causing GM1 gangliosidosis (GM1) and Morquio B disease (MBD), respectively, characterized clinical phenotypes as well as biosynthesis, intracellular transport and subcellular localization of mutants. We recently identified an effective chaperone, DL-HexDGJ (Methyl 6-{[N(2)-(dansyl)-N(6)-(1,5-dideoxy-D-galactitol-1,5-diyl)- L-lysyl]amino} hexanoate), among a series of N-modified 1-deoxygalactonojirimycin derivatives carrying a dansyl group in its N-acyl moiety. Using novel and flexible synthetic routes, we now report on the effects of two oligofluoroalkyl-derivatives of 1-deoxygalactonojirimycin, Ph(TFM)(2)OHex-DGJ (N-(α,α-di-trifluoromethyl) benzyloxyhexyl-1,5-dideoxy-1,5-imino-D: -galactitol) and (TFM)(3)OHex-DGJ (N-(Nonafluoro-tert-butyloxy)hexyl-1,5-dideoxy-1,5-imino-D: -galactitol) on the β-gal activity of GM1 and MBD fibroblasts. Both compounds are competitive inhibitors and increase the residual enzyme activities up to tenfold over base line activity in GM1 fibroblasts with chaperone-sensitive mutations. Western blots showed that this was due to a normalization of protein transport and intralysosomal maturation. The fact that the novel compounds were effective at very low concentrations (0.5-10 μM) in the cell culture medium as well as their novel chemical character suggest future testing in animal models. This may contribute to new aspects for efficient and personalized small molecule treatment of lysosomal storage diseases.
与通过输注外源性重组溶酶体酶进行替代疗法不同，药理学伴侣旨在实现内源性基因产物的功能获得。由于错义突变导致的缺陷，可以通过与催化部位结合的小的竞争性抑制剂来治疗，从而纠正突变酶的错误构象。这可以防止它们过早降解，并使细胞内运输以及生物学半衰期正常化。当前的主要限制是大量的个别错义突变以及缺乏关于与突变蛋白结构域特异性相互作用的结构要求的知识。我们之前对β-半乳糖苷酶（β-gal）基因的突变进行了研究，这些突变分别导致 GM1 神经节苷脂贮积症（GM1）和 Morquio B 病（MBD），其特征是临床表型以及突变体的生物合成，细胞内运输和亚细胞定位。我们最近在一系列 N-酰基部分带有丹磺酰基的 N-修饰 1-脱氧半乳糖基己二酰亚胺衍生物中鉴定出一种有效的伴侣，称为 DL-HexDGJ（甲基 6-[[N（2）-（丹磺酰基）-N（6）-（1,5-二脱氧-D-半乳糖醇-1,5-二基）-L-赖氨酸]氨基]己酸酯）。使用新颖且灵活的合成途径，我们现在报告了两种 1-脱氧半乳糖基己二酰亚胺的低聚氟烷基衍生物，Ph（TFM）（2）OHex-DGJ（N-（α，α-二-三氟甲基）苄基氧基己基-1,5-二脱氧-1,5-亚氨基-D：-半乳糖醇）和（TFM）（3）OHex-DGJ（N-（九氟叔丁氧基）己基-1,5-二脱氧-1,5-亚氨基-D：-半乳糖醇）对 GM1 和 MBD 成纤维细胞中β-gal 活性的影响。这两种化合物均为竞争性抑制剂，可将 GM1 成纤维细胞中伴侣敏感突变的基础活性提高至十倍以上。Western blot 显示，这是由于蛋白质运输和溶酶体内成熟的正常化。新型化合物在细胞培养基中以非常低的浓度（0.5-10μM）有效以及其新颖的化学性质表明，将来可以在动物模型中进行测试。这可能为溶酶体贮积病的有效和个性化小分子治疗提供新的方面。
