Mitochondrial Ion Channels in Hypoxic Neurons

啮齿类动物短暂性全脑缺血（小鼠2条血管闭塞，2 VO）诱导海马迟发性死亡 CA 1神经元，是人类缺血性脑损伤和长期海马记忆缺陷的模型。 在神经元死亡之前发生的事件包括半胱天冬酶和促凋亡Bcl-2家族成员（Bax） 抗死亡Bcl-2家族蛋白Bcl-xL的激活、切割、细胞内Ca 2+失调和大细胞凋亡。 电导线粒体通道活性。开放的大电导，Ca 2+依赖，内部 线粒体膜通道在损伤阶段早期发生，因此识别和靶向 这种内膜通道的研究长期以来一直是基础研究和临床社区的重要目标。 内膜通道被称为线粒体通透性转换孔（mPTP）。它被激活 通过神经元Ca 2+失调和线粒体肽基脯氨酰顺反异构酶的结合 亲环素D（CypD）。据报道，CypD在OSCP处与ATP合酶的定子区结合 亚单位CypD结合被众所周知的mPTP抑制剂环孢菌素A（CsA）抑制，其减弱mPT 通道激活在之前的资助期间，我们是第一个证明ATP合酶 膜包埋的c亚基形成mPTP的最大已知通道，ATP合酶c亚基泄漏 我们发现CsA通过与ATP合成酶F1/定子结合来抑制ACLC活性， 因为当ATP合酶的膜部分被化学地 拆卸F1/定子组件。我们还报道Dex是一种安全的ATP调节剂 合成酶泄漏，直接结合到定子复合物上的OSCP/亚基B。地塞米松可改善 神经发育性脑障碍在本次更新中，我们将重点关注ACLC作为抑制目标 mPTP开放和死亡。通过突变C亚基以降低通道活性，我们将抑制ACLC开放 并在神经元和体内谷氨酸兴奋毒性期间阻止线粒体通透性转换（mPT） 小鼠缺血性脑损伤。我们将确定是否记忆丧失，一个严重的，长期持续的影响，短暂的全球 啮齿类动物和人类的缺血，将通过这种遗传策略来预防。

Transient global ischemia in rodents (2 vessel occlusion in mice, 2VO) induces delayed death of hippocampal CA1 neurons and is a model for human ischemic brain injury and long lasting hippocampal memory deficits. Events that occur before neuronal death include caspase and pro-apoptotic Bcl-2 family member (Bax) activation, cleavage of the anti-death Bcl-2 family protein Bcl-xL, cellular Ca2+ dysregulation and large conductance mitochondrial channel activity. The opening of a large conductance, Ca2+ dependent, inner mitochondrial membrane channel occurs early during the injury phase, therefore the identification and targeting of this inner membrane channel has long been an important goal of both basic research and clinical communities. The inner membrane channel is known as the mitochondrial permeability transition pore (mPTP). It is activated by neuronal Ca2+ dysregulation and by the binding of the mitochondrial peptidyl-prolyl cis-trans isomerase cyclophilin D (CypD). It has been reported that CypD binds to the stator region of the ATP synthase at the OSCP subunit. CypD binding is inhibited by the well-known mPTP inhibitor cyclosporine A (CsA), which attenuates mPT channel activation. During the previous funding period, we were the first to demonstrate that the ATP synthase membrane-embedded c-subunit forms the largest known channel of the mPTP, the ATP synthase c-subunit leak channel (ACLC), and we showed that CsA inhibits ACLC activity by binding within the ATP synthase F1/stator portion because channel inhibition fails to occur when the membrane portions of the ATP synthase are chemically stripped of the F1/stator components. We also reported that Dexpramipexole (Dex) is a safe modulator of ATP synthase leak that binds directly to OSCP/subunit b on the stator complex. Dex ameliorates disease in a neurodevelopmental brain disorder. In this current renewal we will focus on the ACLC as the target to inhibit mPTP opening and death. By mutation of the c-subunit to reduce channel activity, we will inhibit ACLC opening and prevent mitochondrial permeability transition (mPT) during glutamate excitotoxicity in neurons and in vivo ischemic brain injury in mice. We will determine if memory loss, a severe, long lasting effect of transient global ischemia in rodents and humans, will be prevented by this genetic strategy.