Development of in vivo probes to study the function of TRIP8b in cognition

摘要 认知功能障碍是与慢性应激相关的神经精神疾病的共同特征。这些 症状会使人衰弱，尽管像重度抑郁症这样的疾病很普遍， 治疗选择相对较少。为了更好地解决这些症状， needed.超极化激活的环核苷酸门控（HCN）通道在调节细胞内的信号转导中起着关键作用。 海马体的兴奋性，一个与认知密切相关的大脑区域。为了避免心脏副作用 与拮抗HCN通道（也在心脏中表达）相关，我们的团队专注于 TRIP 8b是HCN通道的神经元特异性亚基。在我们最近发表的报告（莱曼等人，在 出版社在科学转化医学），我们建立了化学遗传学破坏的相互作用， TRIP 8b和HCN在背侧海马中的相互作用足以挽救认知障碍， 慢性压力结合起来，这些结果与一种小分子干扰的假设是一致的。 TRIP 8b-HCN相互作用可以挽救慢性应激后观察到的认知功能障碍。为了 利用这一发现，我们小组最近进行了一项高通量筛选， TRIP 8b-HCN相互作用的抑制剂。我们确定了一个候选支架，它显示出有希望的活性 TRIP 8b抑制剂这一化合物系列是我们目前提交的基础， 提出进一步的药物化学优化，以开发TRIP 8b抑制剂用作化学探针， 为了在体内研究TRIP 8b。在我们所附的初步数据中，我们表明我们的抑制剂有效地破坏了 TRIP 8b和HCN在细胞中的相互作用具有可忽略的毒性。这种抑制产生了强大的 对体内和体外HCN通道介导的电流Ih的影响。为了扩大这项工作，我们 提出三个目标。在目标1中，我们将进行迭代药物化学优化，以开发 具有改进的效力和药物特性的化合物。在我们的环境中表现良好的化合物 在目标2中，生物化学和生物物理测定将被推进到细胞测定，以确定它们是否 能够破坏TRIP 8b-HCN相互作用。在目标3中，我们将利用我们的化合物在体内研究 对海马功能的影响有希望的化合物将被调查的能力，拯救 认知缺陷是由长期的社会失败造成的，这是一种慢性压力的动物模型。这些实验 将使我们能够开发TRIP 8b抑制剂，可用作化学探针来研究HCN的作用 通道调节慢性应激后认知功能障碍。

Abstract Cognitive dysfunction is a common feature of neuropsychiatric diseases related to chronic stress. These symptoms can be debilitating, and despite the high prevalence of illnesses like Major Depressive Disorder, there are relatively few treatment options. To better address these symptoms, novel molecular targets are needed. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels play a critical role in regulating excitability in the hippocampus, a brain region critically involved in cognition. To avoid cardiac side effects associated with antagonizing HCN channels (which are also expressed in the heart), our group has focused on TRIP8b, a neuron-specific subunit of HCN channels. In our recently published report (Lyman et al, in press at Science Translational Medicine), we established that chemogenetically disrupting the interaction between TRIP8b and HCN in the dorsal hippocampus is sufficient to rescue impairments in cognition after chronic stress. Combined, these results are consistent with the hypothesis that a small molecule that disrupts the TRIP8b-HCN interaction could rescue the cognitive dysfunction seen after chronic stress. In order to capitalize on this discovery, our group recently executed a high throughput screen to identify small molecule inhibitors of the TRIP8b-HCN interaction. We identified one candidate scaffold which shows promising activity as a TRIP8b inhibitor. This compound series serves as the basis for our current submission in which we propose further medicinal chemistry optimization to develop TRIP8b inhibitors for use as chemical probes in order to study TRIP8b in vivo. In our enclosed preliminary data, we show that our inhibitor potently disrupts the interaction between TRIP8b and HCN in cells with negligible toxicity. This inhibition produces robust effects on Ih, the current mediated by HCN channels both in vivo and in vitro. To expand upon this work, we propose three aims. In Aim 1, we will perform iterative medicinal chemistry optimization to develop compounds with improved potency and pharmaceutical characteristics. Compounds that perform well in our biochemical and biophysical assays will be advanced to cellular assays in Aim 2 in order to determine if they are capable of disrupting the TRIP8b-HCN interaction. In Aim 3 we will utilize our compounds in vivo to study their effect on hippocampal function. Promising compounds will be investigated for their ability to rescue cognitive deficits that result from chronic social defeat, an animal model of chronic stress. These experiments will enable us to develop TRIP8b inhibitors that can be used as chemical probes to study the role of HCN channels in regulating cognitive dysfunction after chronic stress.