Chaperone therapeutics for the treatment of DPN

总结 糖尿病周围神经病变（DPN）的病因学起源于一系列相互关联的代谢紊乱， 以及最终导致感觉神经元变性的血管损伤。在寻求 为了治疗DPN，已经开发了小分子抑制剂来靶向被认为是 “糖尿病特异性”以及在多种疾病状态下增加的那些。这些努力并没有证明 成功的，这表明新的目标，发挥调节蛋白质的基本作用的鉴定 完整性和在糖尿病状态下保持神经功能可能代表一种新的范例。热休克蛋白 热休克蛋白90（Hsp 90）是一种分子伴侣，它结合“客户蛋白”，并促进其折叠成生物学上的蛋白质。 活跃的结构。它也是细胞保护性“热休克反应”的主要调节因子， 在细胞应激时发生的聚集和受损蛋白质的重折叠。N端和C端ATP Hsp 90的结合域调节其与蛋白质的相互作用。Hsp 90的N-末端抑制剂表现出有效的 这些化合物具有抗肿瘤细胞的细胞毒性，并处于临床试验中，但这些化合物也诱导细胞保护作用。 在细胞毒性所需的浓度下的“热休克反应”。相比之下，我们已经开发出了强大的 Hsp 90 C-末端结构域的小分子抑制剂，其神经保护功效表现为： 浓度远低于诱导神经毒性所需的浓度。这些抑制剂的先导化合物KU- 32，是基于新生霉素。KU-32可防止高血糖诱导的感觉神经元死亡， 能通过诱导热休克反应减轻DPN小鼠的几项生理指标。 不幸的是，该分子需要大量的合成制备，从而阻碍了对分子的充分阐明。 结构-活性关系并限制其在动物/人类中的使用。因此，本提案的目标是 提供了衍生自KU-32的新化合物，其表现出更好的神经保护活性， 最少数量的合成程序。初步筛选将确定具有增加功效的化合物 相对于KU-32，将测试主要候选人对感觉神经元血糖应激的保护作用， 随后在野生型和Hsp 70敲除小鼠中进行DPN的动物研究。这项工作的成果将 进一步开发和鉴定小分子C末端Hsp 90抑制剂， 无明显神经毒性。

SUMMARY The etiology of diabetic peripheral neuropathy (DPN) initiates from an inter-related series of metabolic and vascular insults that ultimately contribute to sensory neuron degeneration. In the quest to pharmacologically manage DPN, small molecule inhibitors have been developed to target proteins regarded as "diabetes specific" as well as those that increase in multiple disease states. Such efforts have not proven successful, suggesting the identification of novel targets that play a fundamental role in regulating protein integrity and preserving nerve function in the diabetic state may represent a new paradigm. Heat shock protein 90 (Hsp90) is a molecular chaperone that binds "client proteins" and promotes their folding into biologically active structures. It is also the master regulator of a cytoprotective "heat shock response", which aids the refolding of aggregated and damaged proteins that occur upon cell stress. Both the N- and C-terminal ATP binding domains of Hsp90 regulate its interaction with proteins. N-terminal inhibitors of Hsp90 exhibit potent cytotoxicity against tumor cells and are in clinical trials, but these compounds also induce a cytoprotective "heat shock response" at concentrations necessary for cytotoxicity. In contrast, we have developed potent small molecule inhibitors of the Hsp90 C-terminal domain whose neuroprotective efficacy is manifested at concentrations far below those necessary to induce neuro-toxicity. The lead compound for these inhibitors, KU- 32, is based upon novobiocin. KU-32 protects against hyperglycemia-induced death of sensory neurons and can attenuate several physiologic indices of DPN in mice through induction of the heat shock response. Unfortunately, this molecule requires significant synthetic preparation, thus preventing full elucidation of structure-activity relationships and limiting its use in animals/humans. Thus, the goal of this proposal is to provide new compounds derived from KU-32 that exhibit better neuroprotective activity and can be prepared in a minimal number of synthetic procedures. An initial screen will identify compounds with increased efficacy relative to KU-32 and lead candidates will be tested for protection against glycemic stress of sensory neurons, followed by animal studies of DPN in both wild-type and Hsp70 knockout mice. The outcome of this work will further develop and identify small molecule C-terminal Hsp90 inhibitors that decrease neurodegeneration in the absence of significant neurotoxicity.