Schaertl Sabine, Prime Michael, Wityak John, Dominguez Celia, Munoz-Sanjuan Ignacio, Pacifici Robert E, Courtney Stephen, Scheel Andreas, Macdonald Douglas
Evotec AG, Hamburg, Germany.
J Biomol Screen. 2010 Jun;15(5):478-87. doi: 10.1177/1087057110366035. Epub 2010 Apr 15.
Huntington's disease (HD) is associated with increased expression levels and activity of tissue transglutaminase (TG2), an enzyme primarily known for its cross-linking of proteins. To validate TG2 as a therapeutic target for HD in transgenic models and for eventual clinical development, a selective and brain-permeable inhibitor is required. Here, a comprehensive profiling platform of biochemical and cellular assays is presented which has been established to evaluate the potency, cellular efficacy, subtype selectivity and the mechanism-of-action of known and novel TG2 inhibitors. Several classes of inhibitors have been characterized including: the commonly used pseudo-substrate inhibitors, cystamine and putrescine (which are generally nonspecific for TG2 and therefore not practical for drug development), the various peptidic inhibitors that target the active site cysteine residue (which display excellent selectivity but in general have poor cellular activity), and the allosteric reversible small-molecule hydrazides (which show poor selectivity and a lack of cellular activity and could not be improved despite considerable medicinal chemistry efforts). In addition, a set of inhibitors identified from a collection of pharmacologically active compounds was found to be unselective for TG2. Moreover, inhibition at the guanosine triphosphate binding site has been examined, but apart from guanine nucleotides, no such inhibitors have been identified. In addition, the promising pharmacological profile of a TG2 inhibitor is presented which is currently in lead optimization to be developed as a tool compound.
亨廷顿舞蹈症（HD）与组织转谷氨酰胺酶（TG2）表达水平及活性增加有关，TG2是一种主要因其蛋白质交联作用而为人所知的酶。为了在转基因模型中验证TG2作为HD治疗靶点以及最终用于临床开发，需要一种具有选择性且能透过血脑屏障的抑制剂。在此，本文介绍了一个综合的生化和细胞分析筛选平台，该平台已被建立用于评估已知和新型TG2抑制剂的效力、细胞功效、亚型选择性及作用机制。已对几类抑制剂进行了表征，包括：常用的假底物抑制剂胱胺和腐胺（它们通常对TG2无特异性，因此对药物开发不实用）、靶向活性位点半胱氨酸残基的各种肽类抑制剂（它们具有出色的选择性，但总体细胞活性较差），以及变构可逆小分子酰肼（它们选择性差且缺乏细胞活性，尽管经过大量药物化学努力也无法改进）。此外，从一系列药理活性化合物中鉴定出的一组抑制剂对TG2无选择性。此外，还研究了在三磷酸鸟苷结合位点的抑制作用，但除了鸟嘌呤核苷酸外，尚未鉴定出此类抑制剂。此外，还介绍了一种TG2抑制剂有前景的药理特性，该抑制剂目前正处于先导优化阶段，将被开发为一种工具化合物。
