PAF: Presynaptic and Postsynaptic Mechanisms of Injury in HAND

PAF：手部损伤的突触前和突触后机制

• 批准号: 8789403
• 负责人: JENNETTA W HAMMOND
• 金额: $ 5.43万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-16 至 2017-09-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8789403
• 关键词: AMPA Receptors; Action Potentials; Acute; Address; Anaphylaxis; Autocrine Communication; Autopsy; Biochemical; CXCR3 gene; Calcium Spikes; Cell surface; Cells; Cerebrospinal Fluid; Chronic; Communities; Conditioned Culture Media; Data; Dendritic Spines; Disease; Dyes; Electron Microscopy; Elements; Exhibits; Failure; Fluorescent Probes; Fractionation; Genetic; Glutamates; HIV; HIV Envelope Protein gp120; HIV Seropositivity; Image; Immune; Immune system; Immunofluorescence Immunologic; Impaired cognition; In Vitro; Individual; Inflammation; Inflammation Mediators; Inflammatory; Injury; Label; Lead; Learning; Left; Life; Long-Term Effects; Long-Term Potentiation; Measurement; Mediating; Memory; Microglia; Microscopic; Microscopy; Modeling; Molecular; Monitor; Multiple Sclerosis; Mus; N-Methyl-D-Aspartate Receptors; Nerve; Nervous System Trauma; Nervous system structure; Neuraxis; Neurocognitive; Neuronal Injury; Neurons; Paracrine Communication; Patients; Peripheral; Phospholipids; Phosphorylation; Physiological; Platelet Activating Factor; Platelet aggregation; Play; Population; Pre-Clinical Model; Preparation; Presynaptic Terminals; Proteins; Receptor Inhibition; Receptor Signaling; Recycling; Rodent; Rodent Model; Role; Seizures; Signal Pathway; Signal Transduction; Signaling Molecule; Small Interfering RNA; Stroke; Structure; Symptoms; Synapses; Synaptic Transmission; Synaptic Vesicles; Techniques; Testing; Trauma; Viral; Western Blotting; aging population; antiretroviral therapy; base; experience; feeding; genetic inhibitor; in vivo; insight; mouse model; neuroinflammation; neurotoxic; neurotransmission; neurotransmitter release; optogenetics; platelet activating factor receptor; postsynaptic; presynaptic; public health relevance; trafficking; two-photon

DESCRIPTION (provided by applicant): HIV-associated neurocognitive disorders (HAND) for both the young and aging population remain a huge and growing concern even in the presence of combination antiretroviral therapy (cART). Although viral replication is inhibited by cART, vira proteins such as TAT and gp120 are still produced within the nervous system which are neurotoxic and stimulate inflammation (1, 2). HIV induced neuroinflammation is thought to be a major contributing factor in the cognitive decline exhibited by roughly 50% of HIV-positive individuals (3, 4), but more information on the molecular and cellular mechanisms relevant to this persistent cognitive decline still needs to be addressed. Platelet activating factor (PAF) is n inflammatory mediator that can also alter neurotransmission (5-8). It is present at chronically high levels in patients with HAND as compared to HIV positive individuals without cognitive impairments (9). PAF receptor (PAFR) antagonism has been shown to be neuroprotective in mouse models of HAND and other neuroinflammatory diseases (10-17). Thus, PAF may be a major contributor to the neuronal injury associated with neuroinflammation and HAND because of its ability to modulate synaptic strength. Yet, there is much about the mechanisms of PAF signaling at the synapse that we do not understand including whether it occurs primarily in the presynaptic or postsynaptic compartment or both. I hypothesize that chronic PAF exposure increases neurotransmission leading to neuronal injury by acting on both the pre- and postsynaptic compartments. Enhanced neurotransmitter release and enhanced signal reception places synapses in a high activity state where they are vulnerable to excitotoxic injury and energy failure even in the presence of physiologic levels of stimulation. I will test this hypothess using both in vitro and in vivo techniques. In Aim 1, I will first determining the precise localizaion of the PAFR within the presynaptic and/or postsynaptic compartments. Then I will investigate PAF induced changes to synaptic vesicle organization and the proteins that regulate synaptic vesicle release within the presynaptic compartment. In Aim 2, I will test whether PAF signaling within the postsynaptic compartment is necessary or sufficient for neuronal injury. I will further investigate whether PAF signaling alters NMDA and AMPA receptor trafficking or activation state that would change the signal strength received by the postsynaptic cell. In Aim 3, I will determine the acute and long-term effects of PAF- induced synaptic injury in vivo and in a model of HAND using cutting-edge techniques including intravital multiphoton microscopy using cortical windows and optogenetics. Results from these studies should validate the PAFR signaling pathway as a viable target for the treatment of HAND and other neuroinflammatory diseases as well as increase our understanding of the molecular mechanisms leading to the cognitive decline in HAND patients.

描述（由申请人提供）：即使在联合抗逆转录病毒治疗（cART）的情况下，年轻人和老年人的HIV相关神经认知障碍（HAND）仍然是一个巨大且日益增长的问题。尽管cART抑制了病毒复制，但病毒蛋白如达特和gp 120仍在神经系统内产生，它们具有神经毒性并刺激炎症（1，2）。HIV诱导的神经炎症被认为是大约50%的HIV阳性个体所表现出的认知下降的主要促成因素（3，4），但是与这种持续性认知下降相关的分子和细胞机制的更多信息仍然需要解决。血小板活化因子（PAF）是一种炎症介质，也可以改变神经传递（5-8）。与没有认知障碍的HIV阳性个体相比，HAND患者中的HAND水平长期较高（9）。PAF受体（PAFR）拮抗作用已被证明在HAND和其他神经炎性疾病的小鼠模型中具有神经保护作用（10-17）。因此，PAF可能是与神经炎症和HAND相关的神经元损伤的主要贡献者，因为其能够调节突触强度。然而，有很多关于PAF信号在突触的机制，我们不明白，包括它是否主要发生在突触前或突触后室或两者兼而有之。我推测，慢性PAF暴露增加神经传递，导致神经元损伤的前和突触后车厢。增强的神经递质释放和增强的信号接收使突触处于高活性状态，在这种状态下，即使在生理水平的刺激存在下，它们也容易受到兴奋性毒性损伤和能量衰竭。我将使用体外和体内技术来验证这一假设。在目的1中，我将首先确定PAFR在突触前和/或突触后区室中的精确定位。然后，我将研究PAF引起的突触囊泡组织的变化和调节突触囊泡释放的蛋白质在突触前区室。在目标2中，我将测试是否PAF信号传导在突触后区室是必要的或足够的神经元损伤。我将进一步研究PAF信号是否改变NMDA和AMPA受体的运输或激活状态，从而改变突触后细胞接收的信号强度。在目标3中，我将确定PAF诱导的突触损伤的急性和长期影响，在体内和模型中的手使用尖端技术，包括活体多光子显微镜使用皮层窗口和光遗传学。这些研究的结果应该验证PAFR信号通路作为治疗HAND和其他神经炎性疾病的可行靶点，并增加我们对导致HAND患者认知能力下降的分子机制的理解。