Bivalent Peptidomimetic Ligands of TrkC Are Biased Agonists and Selectively Induce Neuritogenesis or Potentiate Neurotrophin-3 Trophic Signals
Bivalent Peptidomimetic Ligands of TrkC Are Biased Agonists and Selectively Induce Neuritogenesis or Potentiate Neurotrophin-3 Trophic Signals
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DOI：
10.1021/cb9001415
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发表时间：
2009-09-01
影响因子：
4
通讯作者：
Burgess, Kevin
中科院分区：
文献类型：
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作者：
Chen, Dianjun;Brahimi, Fouad;Burgess, Kevin
本研究开始寻找小分子配体，当与神经营养因子Trk受体对接时，其将诱导功能性应答。“极简主义”的P型转弯模仿就是为此目的而设计的。这些模拟物是（i）刚性的，但容易折叠成转角样构象，和（ii）容易从携带大部分天然侧链的氨基酸获得。制备克量的16个这些转模拟物，然后通过溶液相组合方法组装成152个荧光素标记的二价肽模拟物。使用转染有Trk受体的细胞对这些分子进行的基于生物活性的筛选鉴定了TrkC（神经营养因子-3的受体）的10种潜在配体。然后制备用生物素代替荧光素标记的这些二价肽模拟物的类似物，并进行测试以确认结合不是由于荧光素。进行几种测定以发现这些生物素化化合物的作用模式。因此，直接结合、存活和神经突原性以及生化信号转导测定显示，原始10个命中中的8个是结合TrkC胞外域的激动性配体。值得注意的是，一些肽模拟物提供导致细胞存活或神经突分化的离散信号;这项工作的意义是三方面的。首先，我们成功地找到了小的，选择性的，蛋白水解稳定的配体的TrkC受体，有很少的文献中。其次，我们表明，它是可能的激活不同的和有偏见的信号，配体结合在野生型受体的胞外域的途径。第三，一些肽模拟物启动不同模式的细胞信号传导的发现增加了它们作为药理学探针和治疗先导物的潜力。
This study was initiated to find small molecule ligands that would induce a functional,response when docked with neurotrophin Trk receptors. "Minimalist" mimics of P-turns were designed for this purpose. These mimics are (i) rigid, yet easily folded into turn-like conformations, and (ii) readily accessible from amino acids bearing most of the natural side chains. Gram quantities of 16 of these, turn mimics were prepared and then assembled into 152 fluorescein-labeled bivalent peptidomimetics via a solution-phase combinatorial method. Fluorescence-based screening of these molecules using cells transfected with the, Trk receptors identified 10 potential ligands of TrkC, the receptor for neurotrophin-3. Analogues of these bivalent peptidomimetics with biotin replacing the fluorescein label were then prepared and tested to confirm that binding was not due to the fluorescein, Several assays were conducted to find the mode of action of these, biotinylated compounds. Thus, direct binding, survival and neuritogenic, and biochemical signal transduction assays showed 8 of the original 10 hits were agonistic ligands binding to the ectodomain of TrkC. Remarkably, some peptidomimetics afford discrete signals leading to either cell survival or neuritogenic differentiation; The significance of,this work is three-fold. First, we succeeded in finding small, selective, proteolytically stable ligands for the TrkC receptor; there are very few of these in the literature. Second, we show that it is possible to activate distinct and biased signaling, pathways with ligands binding at the ectodomain of wild-type receptors. Third, the discovery that some peptidomimetics initiate different modes of cell signaling increases their potential as pharmacological probes and therapeutic leads.