4-Phenylbutyrate restores the functionality of a misfolded mutant low-density lipoprotein receptor
4-Phenylbutyrate restores the functionality of a misfolded mutant low-density lipoprotein receptor
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DOI：
10.1111/j.1742-4658.2007.05735.x
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发表时间：
2007-04-01
期刊：
影响因子：
5.4
通讯作者：
Kulseth, Mari A.
中科院分区：
文献类型：
--
作者：
Tveten, Kristian;Holla, Oystein L.;Kulseth, Mari A.
家族性高胆固醇血症是一种常染色体显性遗传疾病，由编码低密度脂蛋白受体的基因突变引起。到目前为止，已经描述了900多种不同的突变。运输缺陷突变(2类)导致受体部分或完全滞留在内质网是主要的一类突变。在细胞培养系统(中国仓鼠卵巢细胞)中，我们证明了化学伴侣能够介导运输缺陷突变体(G544V)的拯救，并且获得拯救的能力依赖于突变。特别是，低分子脂肪酸衍生物4-苯基丁酸酯显著增加了G544V突变低密度脂蛋白受体向质膜的转运。30%的突变受体能够从内质网逃逸到细胞表面。被挽救的受体的稳定性降低，但发现在结合和内化低密度脂蛋白方面与野生型低密度脂蛋白受体一样有效。除了4-苯基丁酸酯，我们还研究了3-苯基丙酸酯和5-苯基戊酸酯，并比较了它们对G544V突变低密度脂蛋白受体的挽救作用和它们因组蛋白去乙酰酶抑制活性而导致整体基因表达增加的能力。没有发现相关性。我们的结果表明，这些药物的作用不仅仅是通过它们诱导参与细胞内运输的蛋白质的基因表达来实现的，而可能是由于直接的化学伴侣活性。这些数据表明，挽救突变的低密度脂蛋白受体是可能的，开发药物伴侣来治疗具有2类突变的家族性高胆固醇血症患者可能是可行的。
Familial hypercholesterolemia is an autosomal dominant disease caused by mutations in the gene encoding the low-density lipoprotein receptor. To date, more than 900 different mutations have been described. Transport-defective mutations (class 2) causing partial or complete retention of the receptor in the endoplasmic reticulum are the predominant class of mutations. In a cell culture system (Chinese hamster ovary cells), we show that chemical chaperones are able to mediate rescue of a transport-defective mutant (G544V), and that the ability to obtain rescue is mutation dependent. In particular, the low molecular mass fatty acid derivative 4-phenylbutyrate mediated a marked increase in the transport of G544V-mutant low-density lipoprotein receptor to the plasma membrane. Thirty per cent of the mutant receptor was able to escape from the endoplasmic reticulum and reach the cell surface. The rescued receptor had reduced stability, but was found to be as efficient as the wild-type low-density lipoprotein receptor in binding and internalizing low-density lipoprotein. In addition to 4-phenylbutyrate, we also studied 3-phenylpropionate and 5-phenylvalerate, and compared their effect on rescue of the G544V-mutant low-density lipoprotein receptor with their ability to increase overall gene expression caused by their histone deacetylase inhibitor activity. No correlation was found. Our results indicate that the effect of these agents was not solely mediated by their ability to induce gene expression of proteins involved in intracellular transport, but rather could be due to a direct chemical chaperone activity. These data suggest that rescue of mutant low-density lipoprotein receptor is possible and that it might be feasible to develop pharmacologic chaperones to treat familial hypercholesterolemia patients with class 2 mutations.