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

• 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
• 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

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.

项目摘要 阿片类药物通常用于治疗疼痛，而阿片类药物信号的经典机制 涉及到神经机制。长期服用阿片类药物会产生矛盾的负面影响 痛觉过敏和阿片类药物耐受，并可导致依赖和成瘾。这些负面影响并不是 仅用神经机制来解释。了解非神经细胞在阿片信号转导中的作用 在正常和病理条件下，对于开发新的疼痛干预措施是重要的。 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止痛的关键神经递质。在 伏隔核是成瘾通路的重要脑区，星形胶质细胞表达 微阿片受体(MOR)，并通过钙升高和谷氨酸释放对阿片类药物作出反应。尽管 它们在调节突触传递和突触外谷氨酸中的关键作用尚未有研究确定 星形胶质细胞是否在脊髓痛处理的重要区域--µ-阿片信号中发挥作用 和阿片类抗伤害性作用。我们的初步行为学实验表明，CD38蛋白是一种重要的 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的动物对吗啡的抗伤害性效应显著降低 鞘内，指出星形细胞CD38在脊髓阿片类药物机制中的作用。因此，我们目前 目的是在突触水平上定义：i)脊髓星形胶质细胞在µ-阿片信号转导中的作用和ii)作用 脊髓星形细胞蛋白CD38在µ-阿片信号转导和抗伤害感受中的作用。我们假设星形胶质细胞 通过星形胶质细胞钙蛋白CD38及其受体参与脊髓阿片信号转导 代谢物cADPR。为了验证这一假设，我们将对脊髓星形胶质细胞进行体外钙成像。 使用新开发的基因编码钙指示器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。检测星形胶质细胞CD38在脑内的作用 在突触水平上，我们将测量阿片类药物抑制光遗传神经元的能力 NAV1.8伤害性感受器的突触刺激。将我们的野生型与CD38进行比较 有缺陷的小鼠。我们的结果将表征星形胶质细胞和星形胶质细胞CD38在微阿片类药物中的参与 在脊髓水平上的信号，并将定义前景未被开发的星形胶质细胞的潜力为新的 开发减少成瘾倾向的疼痛干预措施的目标。