Department of Neurology, Massachusetts General Hospital, MassGeneral Institute for Neurodegenerative Disease, 114 16th Street, Charlestown, MA 02129, USA.
J Pharmacol Exp Ther. 2010 Mar;332(3):849-57. doi: 10.1124/jpet.109.158436. Epub 2009 Nov 24.
Aggregation of alpha-synuclein (alphasyn) is a hallmark of sporadic and familial Parkinson's disease (PD) and dementia with Lewy bodies. Lewy bodies contain alphasyn and several heat shock proteins (Hsp), a family of molecular chaperones up-regulated by the cell under stress. We have previously shown that direct expression of Hsp70 and pharmacological up-regulation of Hsp70 by geldanamycin, an Hsp90 inhibitor, are protective against alphasyn-induced toxicity and prevent aggregation in culture. Here, we use a novel protein complementation assay to screen a series of small-molecule Hsp90 inhibitors for their ability to prevent alphasyn oligomerization and rescue toxicity. By use of this assay, we found that several compounds prevented alphasyn oligomerization as measured by decreased luciferase activity, led to a reduction in high-molecular-mass oligomeric alphasyn, and protected against alphasyn cytotoxicity. A lead compound, SNX-0723 (2-fluoro-6-[(3S)-tetrahydrofuran-3-ylamino]-4-(3,6,6-trimethyl-4-oxo-4,5,6,7-tetrahydro-1H-indol-1-yl)benzamide) was determined to have an EC(50) for inhibition of alphasyn oligomerization of approximately 48 nM and was able to rescue alphasyn-induced toxicity. In vivo assessment of SNX-0723 showed significant brain concentrations along with induction of brain Hsp70. With a low EC(50), brain permeability, and oral availability, these novel inhibitors represent an exciting new therapeutic strategy for PD.
α-突触核蛋白（α-syn）的聚集是散发性和家族性帕金森病（PD）及路易体痴呆的标志。路易体含有 α-syn 和几种热休克蛋白（Hsp），Hsp 是一组分子伴侣，在细胞受到压力时被上调。我们之前的研究表明，Hsp70 的直接表达和格尔德霉素（一种 Hsp90 抑制剂）对 Hsp70 的药理学上调对 α-syn 诱导的毒性具有保护作用，并可防止其在培养物中聚集。在这里，我们使用一种新的蛋白质互补测定法来筛选一系列小分子 Hsp90 抑制剂，以评估它们预防 α-syn 寡聚化和挽救毒性的能力。通过使用该测定法，我们发现几种化合物可通过降低荧光素酶活性来阻止 α-syn 寡聚化，导致高分子量寡聚 α-syn 的减少，并能抵抗 α-syn 的细胞毒性。一种先导化合物 SNX-0723（2-氟-6-[[3S]-四氢呋喃-3-基氨基]-4-（3,6,6-三甲基-4-氧代-4,5,6,7-四氢-1H-吲哚-1-基）苯甲酰胺）被确定对 α-syn 寡聚化的抑制 EC（50）约为 48 nM，并且能够挽救 α-syn 诱导的毒性。SNX-0723 的体内评估显示其具有显著的脑浓度，同时诱导脑内 Hsp70 的表达。这些新型抑制剂具有低 EC（50）、脑渗透性和口服可用性，代表了 PD 的一种令人兴奋的新治疗策略。
