Mitochondrial transport and energy metabolism in synaptic transmission and neuronal degeneration and regeneration

突触传递和神经元变性与再生中的线粒体运输和能量代谢

基本信息

批准号：
10915968
负责人：
Zu-hang Sheng
金额：
$ 259.86万
依托单位：
NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10915968
关键词：
Acceleration Acute Address Adult Affect Age Aging Alzheimer&apos s Disease Area Axon Bioenergetics Biology Bipolar Disorder Brain Brain Injuries Brain Ischemia Brain region Cell Death Cells Cellular Metabolic Process Chronic Collaborations Communication Corticospinal Tracts Creatine Deacetylase Deacetylation Disease Progression Distal Energy Metabolism Energy Supply Energy consumption Ensure F-Actin Face Failure Foundations Functional disorder Generations Genes Glucose Growth Hippocampus Human Impairment In Vitro Indiana Induced pluripotent stem cell derived neurons Injections Injury Investigation Ischemia Knockout Mice Knowledge Lead Lesion Link Lysosomes Maintenance Mediating Metabolic Metabolism Mitochondria Mitochondrial Proteins Modeling Molecular Motors Motor Cortex Mus Natural regeneration Nature Nerve Degeneration Neurobiology Neurodegenerative Disorders Neuroglia Neurons Neurosciences Oligodendroglia Organoids Oxygen PAK6 gene Pathologic Pathology Pathway interactions Phosphorylation Phosphotransferases Physiological Play Positioning Attribute Presynaptic Terminals Proteins Proto-Oncogene Proteins c-akt Recovery Regulation Reporting Research Role SLC25A4 gene SLC25A5 gene Signal Pathway Signal Transduction Sirtuins Solid Spinal Cord Spinal cord injury Stress Structure Synapses Synaptic Transmission Synaptic plasticity Testing Therapeutic Universities Vesicle adult neurogenesis aged axon injury axon regeneration axonal degeneration cell motility cell regeneration clinically relevant deprivation exosome frontier healthy aging in vivo Model induced pluripotent stem cell ischemic injury knock-down mitochondrial dysfunction myosin VI nervous system disorder neuron regeneration neuronal cell body neuronal growth neuronal survival newborn neuron novel presynaptic programs recruit repaired response restraint spatiotemporal synaptic depression syntaphilin therapeutic target trafficking

项目摘要

Accomplishment 1. Reveal an energy signaling pathway that recruits and captures presynaptic mitochondria to sustain synaptic efficacy (Li et al., Nature Metabolism 2020; Li and Sheng, Nature Reviews Neuroscience 2022) Presynaptic mitochondria play an essential role in maintaining effective synaptic transmission by generating ATP and sequestering presynaptic Ca2+. Given that only 33% of presynaptic terminals retain mitochondria, revealing mechanisms for recruiting and retaining presynaptic mitochondria will advance our knowledge as how neurons sustain synaptic efficacy and plasticity. In this study, we reveal that sustained activity induces presynaptic energy deficits that can be effectively recovered by recruiting mitochondria through an AMPK-PAK energy signaling pathway. Motile axonal mitochondria are captured at presynaptic terminals via an interplay between myosin VI (myo6) and SNPH. Synaptic activity activates AMPK-PAK signaling that mediates myo6 phosphorylation and drives mitochondria to presynaptic terminals where mitochondria are anchored on F-actin via SNPH. This pathway maintains presynaptic ATP supply during intensive synaptic activity. Disrupting this signaling crosstalk triggers synaptoenergetic deficits, leading to impaired synaptic efficacy and reduced recovery from synaptic depression after prolonged synaptic activity. Thus, our study reveals an energy-sensitive capture of presynaptic mitochondria, thus fine-tuning synaptic plasticity and maintaining synaptic efficacy. Accomplishment 2. Promoting CNS regeneration after spinal cord injury (SCI) by deleting mitochondrial anchor SNPH (Han et al., Cell Metabolism 2020; Cheng et al., Neuron 2022) Mature CNS neurons typically fail to regrowth after injury, and regeneration requires a high level of energy consumption. This is particularly problematic in SCI that acutely damages mitochondria, leading to a local energy crisis in long-projection cortico-spinal tract (CST) axons. We hypothesize that injury-induced mitochondrial damage contributes to the energetic restriction that accounts for regeneration failure. To test this, we collaborated with Dr. Xiao-Ming Xu's lab (Indiana University) by using three SCI models in Snph KO mice, in which axonal mitochondrial transport is robustly increased. We demonstrate that Snph KO mice display enhanced CST axon regeneration passing through the lesion, accelerated regrowth of monoaminergic axons across a transection gap, and increased compensatory sprouting of uninjured CST. Enhancing mitochondrial transport facilitates the delivery of healthy mitochondria from the motor cortex into the regenerating CST axons. Our energy crisis model is further tested by the finding that systemic administration of creatine, a bioenergetic compound, facilitates CST axonal regeneration. Thus, repairing energy supply by enhancing mitochondrial transport or boosting cellular energetics is a promising strategy to promote CNS axonal regeneration after injuries. Accomplishment 3. Reprogramming an energetic AKT-PAK5 signaling axis remobilizes damaged mitochondria for replacement and thus facilitates neuron survival and regeneration after injury-ischemia (Huang et al., Current Biology 2021; Huang and Sheng, Cell Regeneration 2022) Mitochondrial dysfunction and energy crisis are the hallmarks of ischemic injury that typically leads to the cell death within affected brain region. In mature CNS neurons, axonal mitochondrial integrity and content are reduced and ATP levels are significantly declined after oxygen and glucose deprivation, contributing to axonal degeneration. In adult brains, highly enriched SNPH expression results in the vast majority of axonal mitochondria remaining stationary after damaged. These extrinsic insults and intrinsic restrictions lead to an acute energy crisis in injured axons. In this study, we reveal a novel energetic repair signaling axis that boosts axonal energy supply by reprogramming mitochondrial trafficking and anchoring in response to acute injury-ischemic stress in mature neurons and adult brains. PAK5 is a brain mitochondrial kinase with declined expression when neurons mature. PAK5 synthesis and signaling is spatiotemporally reactivated locally within axons in response to ischemic stress and axonal injury. PAK5 signaling remobilizes and replaces damaged mitochondria via the phosphorylation switch that turns off the axonal mitochondrial anchor SNPH. Injury-ischemic insults trigger AKT growth signaling that further activates PAK5 and thus boosts local energy supply by recruiting healthy mitochondria. Thus, our study in in vitro and in vivo models reveals a new mitochondrial signaling axis that responds to injury and ischemia and provides a potential therapeutic strategy for neuronal survival and regeneration by reversing energy crisis. Accomplishment 4. Oligodendrocytes enhance axonal energy metabolism by deacetylation of mitochondrial proteins through transcellular delivery of SIRT2 (Chamberlain and Huang et al., Neuron 2021; Li and Sheng, Current Opinion of Neuroscience 2023) Neurons require mechanisms maintaining local ATP supply in distal axons and synapses, which are particularly vulnerable to bioenergetic failure clinically relevant to axonal pathology and disease progression in neurodegenerative diseases. Thus, revealing mechanisms maintaining or boosting axonal energy supply is an emerging frontier for therapeutic investigation. Considering intricate networks in the human brain where billions of neurons and glial cells wire together, a comprehensive maintenance of axonal bioenergetics must include the contribution of glial cells. Oligodendrocytes (OLs) serve as myelinating cells surrounding axons of the CNS; this unique structure ideally positions OLs to support axonal energy metabolism. In this study, we reveal a new transcellular signaling pathway through which OL-derived NAD-dependent deacetylase sirtuin 2 (SIRT2) boosts axonal energy metabolism by deacetylation of mitochondrial proteins ANT1/ANT2. SIRT2 is undetectable in neurons but highly enriched in mature OLs and released within exosomes. Knockdown of SIRT2 in OLs or deletion of Sirt2 gene in mice abolishes the OL-axon cross talk in boosting axonal bioenergetics. Injection of OL-derived exosomes rescues axonal mitochondrial deficiency in the spinal cord of Sirt2 KO mice. This study suggests that exosome-mediated OL-to-axon delivery of SIRT2 is an efficient and robust mechanism for boosting axonal mitochondrial energetic capacity, thus providing a therapeutic target for restoring axonal energy deficits in neurological disorders.

成就1。揭示了一种能量信号通路，该通路可募集并捕获突触前线粒体以维持突触功效（Li等人，自然代谢2020; Li and Sheng，li and Sheng，自然评论神经科学2022））突触前线粒体通过产生ATP和隔离突触前Ca2+来维持有效的突触传播中起着至关重要的作用。鉴于，只有33％的突触前末端保留了线粒体，这揭示了募集和保留突触前线粒体的机制，因为神经元如何维持突触功效和可塑性，我们的知识将促进我们的知识。在这项研究中，我们揭示了持续的活性引起突触前缺陷，可以通过通过AMPK-PAK能量信号通路募集线粒体来有效地恢复。运动轴突线粒体通过肌球蛋白VI（MyO6）和SNPH之间的相互作用在突触前终端捕获。突触活性激活了介导肌6磷酸化的AMPK-PAK信号传导，并将线粒体驱动到突触前末端，其中线粒体通过SNPH固定在F-肌动蛋白上。该途径在强化突触活动期间保持突触前ATP供应。破坏这种信号串扰的触发器触发突触词，从而导致突触功效受损，并在长时间的突触活性后从突触抑郁症中恢复。因此，我们的研究揭示了突触前线粒体的能量敏感性捕获，从而微调突触可塑性并保持突触功效。成就2。通过删除线粒体锚SNPH促进CNS再生（SCI）（SCI）（Han等人，细胞代谢2020; Cheng等，Neuron 2022）成熟的CNS神经元通常在受伤后无法再生，而再生需要高度的能耗。这在SCI中尤其有问题，急性损害线粒体，导致长期投射皮质脊柱（CST）轴突的局部能量危机。我们假设损伤引起的线粒体损伤有助于导致再生失败的能量限制。为了测试这一点，我们通过在SNPH KO小鼠中使用三种SCI模型与Xiao-Ming Xu的实验室（印第安纳大学）合作，其中轴突线粒体运输可强大增加。我们证明，SNPH KO小鼠表现出增强的CST轴突再生，穿过病变，跨横向间隙加速了单胺能轴突的再生，并增加了未损坏的CST的补偿性发芽。线粒体转运增强，促进了从运动皮层中健康的线粒体传递到再生的CST轴突。通过发现肌酸的系统给药促进CST轴突再生的发现进一步测试了我们的能源危机模型。因此，通过增强线粒体转运或增强细胞能量来修复能量供应是促进受伤后CNS轴突再生的有前途策略。成就3。重新编程能量的Akt-Pak5信号轴重新拟合受损的线粒体以进行替换，从而促进了损伤 - 异常后的神经元的生存和再生（Huang等人，Curturn Biology 2021; Huang和Huang and Sheng，Cell Renenation 2022）线粒体功能障碍和能量危机是缺血性损伤的标志，通常导致受影响的大脑区域内的细胞死亡。在成熟的中枢神经系统神经元中，轴突线粒体完整性和含量降低，ATP水平在氧气和葡萄糖剥夺后显着下降，导致轴突变性。在成年大脑中，高度富集的SNPH表达会导致绝大多数轴突线粒体在受损后保持静止。这些外部侮辱和内在限制会导致受伤的轴突发生急性能量危机。在这项研究中，我们揭示了一个新型的能量修复信号传导轴，该轴通过重新编程线粒体运输和锚定，以响应成熟神经元和成人大脑的急性损伤 - 缺血性压力来提高轴突能量。 PAK5是一种脑线粒体激酶，神经元成熟时表达下降。 PAK5的合成和信号传导是响应缺血性应力和轴突损伤的轴突中局部局部重新激活的。 PAK5信号传递通过磷酸化开关替代了损坏的线粒体，该磷酸化开关关闭了轴突线粒体锚snph。损伤 - 缺血性损伤会触发AKT增长信号，从而进一步激活PAK5，从而通过募集健康的线粒体来增强局部能量供应。因此，我们在体外和体内模型方面的研究揭示了一种新的线粒体信号轴，该信号轴对损伤和缺血反应，并通过逆转能量危机为神经元存活和再生提供了潜在的治疗策略。成就4。少突胶质细胞通过跨细胞递送SIRT2通过脱乙酰基来增强轴突能代谢（Chamberlain和Huang等人，Neuron 2021; li and li and Sheng; li and sheng; li and sheng; 神经元需要在远端轴突和突触中维持局部ATP供应的机制，这些机制在临床上与轴突病理学和神经退行性疾病的疾病进展有关。因此，揭示维持或增强轴突能供应的机制是用于治疗研究的新兴领域。考虑到数十亿个神经元和神经胶质细胞连接在一起的复杂网络，轴突生物能量的全面维持必须包括神经胶质细胞的贡献。少突胶质细胞（OLS）充当CNS轴突周围的髓鞘细胞；这种独特的结构理想地定位了OLS以支持轴突能代谢。在这项研究中，我们揭示了一种新的跨细胞信号传导途径，通过该途径依赖性NAD依赖性脱乙酰基酶SIRTUIN 2（SIRT2）通过将线粒体蛋白ANT1/ANT2脱乙酰化来增强轴突能代谢。 SIRT2在神经元中无法检测到，但在成熟的OL中高度富集并在外泌体内释放。在OLS中敲除SIRT2或在小鼠中删除SIRT2基因的删除，从而消除了促进轴突生物能学的Ol-axon横式演讲。注射OL来源外泌体在SIRT2 KO小鼠的脊髓中挽救了轴突线粒体缺乏。这项研究表明，外泌体介导的SIRT2的OL到轴递送是一种有效且可靠的机制，用于增强轴突线粒体能量能力，从而为恢复神经疾病中轴突能量缺陷提供了治疗靶标。