University of Alberta, Edmonton, AB, Canada.
J Neurochem. 2019 Mar;148(6):761-778. doi: 10.1111/jnc.14661. Epub 2019 Feb 12.
Inflammatory insult to the central nervous system (CNS) can lead to development of depression, and subsequently depression is the most frequent psychiatric comorbidity following ischemic stroke, often limiting recovery and rehabilitation in patients. The initiators of inflammatory pathways in the CNS are microglia activated in response to acute ischemic stress, and anti-depressants have been shown to have anti-inflammatory effects in the CNS, promoting neuronal survival following ischemic insult. We have previously shown that the selective serotonin reuptake inhibitors (SSRIs) fluoxetine and citalopram promote neuronal survival after oxygen-glucose deprivation, an in vitro model of ischemia, by attenuating the release of glutamate and D-serine from activated microglia. Interestingly, we found that fluoxetine-treated microglial cultures contained fewer numbers of cells compared to other groups and hypothesized that fluoxetine and citalopram attenuated the release of glutamate and D-serine by promoting the apoptosis of microglia. The present study aimed to test and compare antidepressants from three distinct classes (tricyclics, monoamine oxidase inhibitors, and SSRIs) on microglial apoptosis. Primary microglia were treated with 1 μg/mL lipopolysaccharide and/or 10 μM antidepressants, and various apoptotic markers were assayed. Fluoxetine and its metabolite norfluoxetine decreased protein levels in cell lysates, decreased cell viability of microglia, and increased the expression of the apoptotic marker cleaved-caspase 3 in microglia. Live/dead nuclear staining also showed that fluoxetine- or norfluoxetine-treated cultures contained greater numbers of dying microglial cells compared to vehicle-treated cultures. Cultures treated with citalopram, phenelzine, or imipramine showed no evidence of inducing microglial apoptosis. Our results demonstrate that fluoxetine and norfluoxetine induce the apoptotic death of microglia, which may serve as a mechanism to attenuate the release of glutamate and D-serine from activated microglia. OPEN SCIENCE BADGES: This article has received a badge for Open Materials because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.
中枢神经系统（CNS）的炎症损伤可导致抑郁的发生，而抑郁是缺血性脑卒中后最常见的精神共病，常常限制患者的康复。CNS 中炎症途径的启动者是对急性缺血应激反应而被激活的小胶质细胞，抗抑郁药已被证明具有 CNS 的抗炎作用，可促进缺血损伤后的神经元存活。我们之前已经表明，选择性 5-羟色胺再摄取抑制剂（SSRIs）氟西汀和西酞普兰通过减弱激活的小胶质细胞中谷氨酸和 D-丝氨酸的释放，促进氧葡萄糖剥夺后的神经元存活，氧葡萄糖剥夺是一种体外缺血模型。有趣的是，我们发现与其他组相比，用氟西汀处理的小胶质细胞培养物中的细胞数量较少，并假设氟西汀和西酞普兰通过促进小胶质细胞凋亡来减弱谷氨酸和 D-丝氨酸的释放。本研究旨在测试和比较来自三个不同类别（三环类抗抑郁药、单胺氧化酶抑制剂和 SSRIs）的抗抑郁药对小胶质细胞凋亡的影响。用 1μg/mL 脂多糖和/或 10μM 抗抑郁药处理原代小胶质细胞，并检测各种凋亡标志物。氟西汀及其代谢物去甲氟西汀降低细胞裂解物中的蛋白水平，降低小胶质细胞的细胞活力，并增加小胶质细胞中凋亡标志物 cleaved-caspase 3 的表达。活/死核染色也表明，与用载体处理的培养物相比，用氟西汀或去甲氟西汀处理的培养物中含有更多死亡的小胶质细胞。用西酞普兰、苯乙肼或丙咪嗪处理的培养物没有诱导小胶质细胞凋亡的证据。我们的结果表明，氟西汀和去甲氟西汀诱导小胶质细胞凋亡，这可能是减弱激活的小胶质细胞中谷氨酸和 D-丝氨酸释放的一种机制。
