The neural circuitry of seizure-induced apnea and SUDEP

癫痫发作引起的呼吸暂停和 SUDEP 的神经回路

• 批准号: 10719519
• 负责人: Ian Christopher Wenker
• 金额: $ 40.38万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2028-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10719519
• 关键词: Acute; Address; Apnea; Benchmarking; Brain; Brain Mapping; Brain Stem; Breathing; Bypass; Cardiac; Cause of Death; Cell Nucleus; Cessation of life; Chromosome Mapping; Clonic Seizure; Data; Development; Electrophysiology (science); Elements; Epilepsy; Experimental Designs; FOXP2 gene; Failure; Generations; Genetic; Heart Arrest; In Vitro; Individual; Injections; Interruption; Maps; Midbrain structure; Modeling; Motor Seizures; Mus; Muscle; Mutant Strains Mice; Mutation; National Institute of Neurological Disorders and Stroke; Nerve Fibers; Neurons; Nodal; Patients; Pattern; Phase; Pontine structure; Prevention strategy; Prosencephalon; Recovery; Refractory; Research; Respiratory Failure; Risk Factors; Role; SCN8A gene; Seizures; Site; Slice; Structure; Sudden Death; Techniques; Testing; Tonic Seizures; Vagus nerve structure; Work; afferent nerve; hindbrain; in vivo; mouse model; mutant; neural; neural circuit; neuronal circuitry; neuronal excitability; novel; optogenetics; parabrachial nucleus; patch clamp; prevent; receptor; recruit; respiratory; selective expression; sudden unexpected death in epilepsy; ventilation

Sudden Unexpected Death in Epilepsy (SUDEP) accounts for up to 17% of all epilepsy-related deaths, and 50% for those refractory to treatment. There is increasing evidence that apnea (respiratory arrest) is the primary cause of death from SUDEP. We have shown in a number of mouse models - including PTZ injection, rapid kindling (prelim. data), and mouse models harboring Scn8a mutations identified from SUDEP patients - that sudden death is due to seizure-induced apnea (SIA) that occurs during tonic seizures, minutes prior to terminal asystole. As it pertains to this proposal, we have also made four other important observations: 1) artificial ventilation can prevent death and suppressed cardiac activity does not increase likelihood of fatality; 2) tonic contraction of breathing muscles represents a likely mechanism of SIA; 3) inhibition of cortical seizure activity does not impact SIA; and 4) inhibition of the inspiratory oscillator does not reduce apnea (prelim. data), suggesting seizure spread bypasses homeostatic elements of respiratory control circuitry. CENTRAL HYPOTHESIS: [AIM 1] Increased midbrain and pontine excitability is both necessary and sufficient to produce SIA, [AIM 2] the parabrachial/kölliker fuse (PB/KF) nucleus in the pons represents a key nodal point for SIA generation, and [AIM 3] that brainstem nuclei, like the PB/KF and PAG are recruited specifically during SIA, which we will explore using electrophysiology and genetic mapping. AIM 1: We have previously used chemogenetics to demonstrate that cortical ictal activity is not required for SIA and we now propose that hyperexcitability of the pons and midbrain drive SIA and SUDEP. We will use chemogenetics to inhibit different parts of the brainstem of Scn8a mutant mice to test their necessity for SIA and SUDEP. Additionally, we will test sufficiency of these regions by selectively expressing an Scn8a mutation that increases neuronal excitability. Using the rapid kindling model, we will also perform patch clamp recordings to test whether increased neuronal excitability in these regions occurs concurrently with the development of SIA. AIM 2: The parabrachial/kölliker fuse nucleus PB/KF in the Pons is a key nodal point for descending forebrain input and projects past the inspiratory oscillator, and is modulated by the vagus nerve. In this aim, we will photoinhibit the Foxp2-positive PB/KF neurons to regain normal breathing pattern during SIA, photostimulate P2ry1-positive vagal afferent nerve fibers to interrupt inspiration during SIA, and determine if PB/KF and Npy2r-positive vagal neuron photostimulation rescues postictal breathing in our PTZ SUDEP mouse model. AIM 3: We have demonstrated that tonic seizures with SIA and clonic seizures without SIA can occur in the very same mouse, both in Scn8a mutant and rapid kindling models (prelim. data) and that certain mid- and hindbrain structures are activated during SIA. We will determine the neuronal circuitry activated specifically during SIA and SUDEP using in vivo electrophysiology and TRAP2 identification of activated neurons.

癫痫猝死（SUDEP）占所有癫痫相关死亡的17%， 50%为难治性。越来越多的证据表明，呼吸暂停（呼吸停止）是 SUDEP的主要死因。我们已经在许多小鼠模型中显示了-包括PTZ注射， 快速点燃（prelim.数据），以及从SUDEP患者中鉴定的携带Scn 8a突变的小鼠模型- 猝死是由于强直性癫痫发作期间发生的呼吸暂停（SIA）， 到晚期心搏停止关于这项建议，我们还提出了其他四项重要意见： 1)人工通气可以预防死亡，抑制心脏活动不会增加死亡的可能性; 2)呼吸肌的紧张性收缩可能是SIA的机制; 3）抑制皮层癫痫发作 活动不影响SIA;和4）吸气振荡器的抑制不减少呼吸暂停（初步）。数据）， 表明癫痫蔓延绕过了呼吸控制回路的稳态元件。中央 假设：[目的1]增加中脑和脑桥兴奋性是必要的，也是足够的， 产生SIA，[AIM 2]脑桥中的臂旁/kölliker融合（PB/KF）核代表了一个关键的节点 点SIA一代，和[AIM 3]，脑干核，如PB/KF和PAG招募 特别是在SIA期间，我们将使用电生理学和遗传图谱进行探索。目标1：我们 以前曾用化学遗传学证明SIA不需要皮层发作活动，现在我们 提出脑桥和中脑兴奋过度驱动SIA和SUDEP。我们将利用化学遗传学 抑制Scn 8a突变小鼠脑干的不同部分，以测试它们对SIA和SUDEP的必要性。 此外，我们将通过选择性表达Scn 8a突变来测试这些区域的充分性， 神经元兴奋性使用快速点燃模型，我们还将进行膜片钳记录，以测试是否 这些区域中神经元兴奋性的增加与SIA的发展同时发生。目标2： 脑桥中的臂旁/kölliker融合核PB/KF是下行前脑输入的关键节点， 投射经过吸气振荡器，并由迷走神经调节。为此，我们将光抑制 Foxp 2阳性PB/KF神经元在SIA期间恢复正常呼吸模式，光刺激P2 ry 1阳性 迷走传入神经纤维中断SIA期间的吸气，并确定PB/KF和Npy 2 r阳性迷走神经纤维是否 在我们的PTZ SUDEP小鼠模型中，神经元光刺激挽救了发作后呼吸。目标3：我们有 证明了具有SIA的强直性癫痫发作和不具有SIA的阵挛性癫痫发作可以发生在同一小鼠中， 在Scn 8a突变体和快速点燃模型（prelim.某些中脑和后脑结构 在SIA期间激活。我们将确定在SIA和SUDEP期间特异性激活的神经元回路， 激活神经元的体内电生理学和TRAP 2鉴定。