Seizures Epileptogenesis and TrkB Transactivation

描述(申请人提供)：神经营养素受体TrkB在神经元存活和分化以及突触结构、功能和可塑性中发挥关键作用。TrkB信号也与多种精神和神经疾病有关。值得注意的是，TrkB在边缘癫痫发生过程中被激活，并且是必需的。了解TrkB的激活机制将有助于深入了解其在健康和疾病中的多效性功能。反式激活是指给定的受体及其下游信号被不直接与受体相互作用的刺激激活的过程，这一机制不同于神经营养因子(如BDNF)激活TrkB。我们最近发现，二价阳离子锌可以通过一种活性依赖和神经营养因子不依赖的机制反式激活培养神经元中的TrkB。锌是否在体内反式激活TrkB，如果是，其生理和病理后果尚不清楚。这一应用的中心是锌在体内和体外对TrkB的假想反式激活。将评估三个水平的分析：体外膜和组织中pTrkB和TrkB的生化和免疫组织化学测量；体外切片中海马苔藓纤维-CA3锥体突触的增强；以及体内点燃和匹罗卡品模型中癫痫的发生。我们将确定囊泡锌是否在体内反式激活TrkB；苔藓纤维-CA3锥体突触的LTP是否需要囊泡锌；以及体内边缘癫痫的发生是否需要囊泡锌。这项拟议工作的成功完成将阐明锌在体内TrkB反式激活中的作用，从而阐明神经营养因子和非神经营养因子配体对TrkB的激活。了解TrkB是如何被激活的很重要，因为TrkB信号在哺乳动物神经系统发育和成年期以及在健康和疾病中都扮演着重要的角色。 公共卫生相关性：神经营养素受体TrkB在哺乳动物神经系统的功能中起着关键作用，无论是健康还是疾病。了解TrkB被激活的机制将有助于深入了解其在健康和疾病中的许多功能。在这里，我们将测试一种新的和意想不到的激活TrkB的机制是否发生在活着的小鼠身上。也就是说，我们询问二价阳离子锌是否在体内激活TrkB。

DESCRIPTION (provided by applicant): The neurotrophin receptor, TrkB, serves a pivotal role in neuronal survival and differentiation as well as in synaptic structure, function, and plasticity. TrkB signaling has also been implicated in diverse psychiatric and neurological disorders. Notably, TrkB is activated during and is required for limbic epileptogenesis. Understanding the mechanisms by which TrkB is activated will provide insight into its pleiotropic functions in health and disease. Transactivation refers to the process whereby a given receptor and its downstream signaling is activated by a stimulus that does not interact directly with the receptor, a mechanism distinct from activation of TrkB by neurotrophins such as BDNF. We recently discovered that the divalent cation, zinc, can transactivate TrkB in cultured neurons by an activity dependent and neurotrophin independent mechanism. Whether zinc transactivates TrkB in vivo and, if so, it's physiological and pathological consequences are unknown. This application centers on the hypothesized transactivation of TrkB by zinc, both in vivo and in slices ex vivo. Three levels of analysis will be assessed: biochemical and immunohistochemical measures of pTrkB and TrkB in membranes and tissue ex vivo; potentiation of the hippocampal mossy fiber-CA3 pyramid synapse in slices ex vivo; and epileptogenesis in the kindling and pilocarpine models in vivo. We will determine whether vesicular zinc transactivates TrkB in vivo; whether vesicular zinc is required for LTP of the mossy fiber-CA3 pyramid synapse; and whether vesicular zinc is required for limbic epileptogenesis in vivo. Successful completion of the proposed work will clarify the role of zinc in transactivation of TrkB in vivo and thereby shed light on the activation of TrkB by both neurotrophin and non-neurotrophin ligands. Understanding how TrkB is activated is important because of the seminal role of TrkB signaling in the mammalian nervous system in development and adulthood and in both health and disease. PUBLIC HEALTH RELEVANCE: The neurotrophin receptor, TrkB, serves a pivotal role in the function of the mammalian nervous system in both health and disease. Understanding the mechanisms by which TrkB is activated will provide insight into its many functions in health and disease. Here we will test whether a novel and an unexpected mechanism of activating TrkB, occurs in living mice. That is, we ask whether the divalent cation zinc activates TrkB in vivo.