Role of astrocytes and astrocytic CD38 in spinal opioid signaling

星形胶质细胞和星形胶质细胞 CD38 在脊髓阿片信号传导中的作用

基本信息

批准号：
10593180
负责人：
Ruth E Quintana
金额：
$ 4.71万
依托单位：
UNIVERSITY OF MINNESOTA
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-04-01 至 2024-09-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10593180
关键词：
American Analgesics Animals Astrocytes Behavioral Brain Brain region Calcium Calcium Signaling Cells Chronic Communication Cyclic ADP-Ribose Data Dependence Development Electrophysiology (science)Enzymes Future Glutamates Goals Grant Histologic Homeostasis Hospitalization Hyperalgesia Intervention Knowledge Literature Measures Mediating Methods Mission Mus National Institute of Drug Abuse Neuroglia Neurons Neurotransmitters Nicotinamide adenine dinucleotide Nociceptors Nucleus Accumbens Opiate Addiction Opioid Opioid Analgesics Opioid Receptor Outcome Pain Pain management Pathologic Pathway interactions Play Proteins Public Health Regulation Research Role Signal Transduction Site Slice Spinal Spinal Cord Synapses Synaptic Transmission Testing Therapeutic Vertebral column Wild Type Mouse Work addiction addiction liability antinociception calcium indicator chronic pain management experimental study improved morphine administration next generation novel opiate tolerance opioid overdose optogenetics pain processing pain signal response side effect spinal cord imaging trend

项目摘要

Project Summary Opioids are commonly prescribed for the treatment of pain, and the classic mechanism of opioid signaling involves neuronal mechanisms. Chronic opioid administration results in negative effects like paradoxical hyperalgesia and opioid tolerance and can lead to dependence and addiction. These negative effects are not explained by neuronal mechanisms alone. Understanding the role of non-neuronal cells in opioid signaling during normal and pathological conditions is important for the development of novel pain interventions. Astrocytes, classically considered supportive cells, are now known to have important roles in modulating synaptic transmission and extrasynaptic glutamate a key neurotransmitter in pain and opioid analgesia. In the nucleus accumbens, an important brain region for addiction pathways, astrocytes have been shown to express µ-opioid receptors (MOR) and to respond to opioids with calcium elevations and glutamate release. Despite their critical role in modulating synaptic transmission and extrasynaptic glutamate, no studies have determined whether astrocytes play a role in µ-opioid signaling in the spinal cord, an important region for pain processing and opioid antinociception. Our preliminary behavioral experiments show that the protein CD38, an important protein responsible for calcium homeostasis, is expressed exclusively in astrocytes in the spinal cord, and animals deficient in CD38 had markedly reduced antinociceptive efficacy to morphine administered intrathecally, pointing to a role of astrocytic CD38 in spinal opioid mechanisms. Therefore, our current objectives are to define at the synaptic level: i) the role of spinal astrocytes in µ-opioid signaling and ii) the role of spinal astrocytic protein CD38, in µ-opioid signaling and antinociception. We hypothesize that astrocytes are involved in spinal opioid signaling via mechanisms that engage the astrocytic calcium protein CD38 and its metabolite cADPR. To test this hypothesis, we will perform ex vivo calcium imaging of spinal cord astrocytes using newly developed genetically encoded calcium indicators and electrophysiological readouts to measure the release of glutamate by astrocytes following opioid stimulation. To test the role of astrocytic CD38 in antinociception at the synaptic level, we will measure the ability of the opioid to inhibit optogenetic neuronal synaptic stimulation of Nav 1.8 nociceptors. Comparisons will be made between our wild type and CD38 deficient mice. Our results will characterize the involvement of astrocytes and astrocytic CD38 in µ-opioid signaling at the spinal level and would define the promising underexplored potential of astrocytes as novel targets for the development of pain interventions with reduced addiction liability.

项目概要阿片类药物通常用于治疗疼痛，阿片类药物信号传导的经典机制涉及神经机制。长期服用阿片类药物会导致矛盾等负面影响。痛觉过敏和阿片类药物耐受并可导致依赖性和成瘾，这些负面影响并不存在。仅通过神经机制来解释非神经元细胞在阿片类信号传导中的作用。在正常和病理条件下进行治疗对于开发新型疼痛干预措施非常重要。星形胶质细胞，传统上被认为是支持细胞，现在已知在调节中具有重要作用突触传递和突触外谷氨酸是疼痛和阿片类镇痛的关键神经递质。伏隔核是成瘾途径的重要大脑区域，星形胶质细胞已被证明表达 μ-阿片受体（MOR）并通过钙升高和谷氨酸释放来响应阿片类药物。它们在调节突触传递和突触外谷氨酸方面的关键作用，尚无研究确定星形胶质细胞是否在脊髓（疼痛处理的重要区域）的 µ-阿片类信号传导中发挥作用我们的初步行为实验表明，蛋白质 CD38 是一种重要的抗镇痛作用。负责钙稳态的蛋白质，仅在脊髓中的星形胶质细胞中表达，并且缺乏 CD38 的动物对吗啡的镇痛效果显着降低鞘内注射，表明星形细胞 CD38 在脊髓阿片类药物机制中的作用。目标是在突触水平上定义：i) 脊髓星形胶质细胞在 µ-阿片类信号传导中的作用，以及 ii) 脊髓星形胶质细胞蛋白 CD38 在 µ-阿片类信号传导和反作用中的作用我们发现星形胶质细胞是通过与星形细胞钙蛋白 CD38 及其结合的机制参与脊髓阿片类药物信号传导为了检验这一假设，我们将对脊髓星形胶质细胞进行离体钙成像。使用新开发的基因编码钙指示剂和电生理读数来测量阿片类药物刺激后星形胶质细胞释放谷氨酸以测试星形胶质细胞 CD38 在中的作用。在突触水平上的预期感受，我们将测量阿片类药物抑制光遗传学神经元的能力 Nav 1.8 伤害感受器的突触刺激将在我们的野生型和 CD38 之间进行比较。我们的结果将描述星形胶质细胞和星形细胞 CD38 在 µ-阿片类药物中的参与情况。脊髓水平的信号传导，并将星形胶质细胞未被充分开发的潜力定义为新颖的制定减少成瘾倾向的疼痛干预措施的目标。