microRNAs and Anesthetic-Induced Developmental Neurotoxicity

microRNA 和麻醉诱导的发育神经毒性

• 批准号: 9024592
• 负责人: Xiaowen Bai
• 金额: $ 29.07万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-05-15 至 2019-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9024592
• 关键词: Anesthesia procedures; Anesthetics; Animal Model; Apoptosis; Attenuated; Brain; Cell Death; Child; Childhood; Complex; Data; Development; Discipline of obstetrics; Disease; Dose; Down-Regulation; Exhibits; Exposure to; Gene Expression; General anesthetic drugs; Health; Human; Knock-out; Knockout Mice; Learning Disabilities; Mediating; Medicine; MicroRNAs; Mitochondria; Molecular; Mus; Neonatal; Nerve Degeneration; Neurons; Pathologic Processes; Pathway interactions; Phase; Physiology; Play; Population; Predisposition; Pregnant Women; Process; Propofol; Proto-Oncogene Proteins c-akt; Reporting; Research; Role; Safety; Sedation procedure; Signal Pathway; Stem cells; Testing; Time; Translating; Untranslated RNA; Up-Regulation; Wild Type Mouse; base; cell type; clinically relevant; developmental neurotoxicity; human embryonic stem cell; innovation; long term memory; loss of function; mitochondrial permeability transition pore; nervous system disorder; neuron loss; neuroprotection; neurotoxic; neurotoxicity; novel; overexpression; prevent; synaptogenesis

DESCRIPTION (provided by applicant): Growing evidence demonstrates that prolonged exposure to general anesthetics induces widespread neuronal cell death followed by long-term memory and learning disability in animal models, raising serious concerns about the safety of obstetric and pediatric anesthesia. Although the underlying mechanisms of increased anesthetic-induced neurotoxicity are complex and just beginning to be understood, our exciting preliminary data point to the role of microRNAs in neurotoxicity. MicroRNAs are endogenous, small, non- coding RNAs that are powerful regulators in normal development and physiology, and diseases through inhibition of target gene expression. Specifically, miR-21 has been shown to decrease apoptosis in varying cell types. Based on our preliminary data and previous reports by others, we hypothesized that the increased mitochondrial fission conferred by downregulated miR-21 contributes to the anesthetic (propofol) neurotoxicity. Propofol is most widely used for sedation and anesthesia in pediatric and obstetric medicine. We propose to utilize gain- and loss-of-function approaches to examine the role of miR-21 in propofol neurotoxicity in mice, translate the findings to humans using stem cell-derived neurons, and investigate the following molecular mechanisms underlying the roles of miR-21 effect: miR-21 targets and suppresses programmed cell death 4 (PDCD4), which can: 1) activate protein kinase B (Akt), 2) decrease mitochondrial fission, delay opening of mitochondrial permeability transition pore (mPTP), and 3) reduce cell death. Downregulated miR-21, upregulated PDCD4, attenuated activation of Akt, and increased mitochondrial fission are likely to contribute to the neurotoxicity conferred by propofol. Our initial exciting data indicate that propofol causes downregulation of miR-21 in stem cell-derived human neurons. In addition, miR-21 knockout increases the vulnerability of mouse developmental neurons and human neurons to propofol exposure. Overexpression of miR-21 attenuated propofol-induced apoptosis in cultured human neurons. Moreover, the reduction of miR-21 is accompanied with a decrease of Akt activation, an increase of mitochondrial fission, and an increase in mPTP opening in human neurons, strongly supporting our hypothesis. We propose the following Specific Aims for the next five years to test our hypotheses: 1) to examine the role of miR-21 in propofol neurotoxicity in mouse brains; 2) to determine the role of miR-21 in propofol neurotoxicity in human neurons; and 3) to determine the role of miR-21/PDCD4/mitochondrial fission pathway in propofol neurotoxicity in human neurons and mouse brains. This is a highly clinically relevant study that is innovative and at the forefront in this field. Based on the findings from this proposed study, we can develop more rational neuroprotection strategies, leading to major advances toward assuring the safety of anesthesia in pediatric populations.

描述（由申请人提供）：越来越多的证据表明，在动物模型中，全身麻醉剂的长期暴露会诱导广泛的神经元细胞死亡，随后出现长期记忆和学习障碍，引起了对产科和儿科麻醉安全性的严重担忧。尽管麻醉诱导的神经毒性增加的潜在机制很复杂，而且刚刚开始被理解，但我们令人兴奋的初步数据表明microRNA在神经毒性中的作用。微小RNA是内源性的、小的、非编码RNA，其通过抑制靶基因表达而在正常发育和生理以及疾病中是强有力的调节剂。具体而言，miR-21已显示在不同细胞类型中减少细胞凋亡。基于我们的初步数据和其他人以前的报告，我们假设下调miR-21所引起的线粒体分裂增加有助于麻醉剂（丙泊酚）的神经毒性。异丙酚最广泛地用于儿科和产科医学中的镇静和麻醉。我们建议利用获得和丧失功能的方法来检查miR-21在小鼠丙泊酚神经毒性中的作用，使用干细胞衍生的神经元将结果转化为人类，并研究miR-21作用的以下分子机制：miR-21靶向并抑制程序性细胞死亡4（PDCD 4），它可以：1）激活蛋白激酶B（Akt），2）减少线粒体分裂，延迟线粒体通透性转换孔（mPTP）开放，3）减少细胞死亡。下调miR-21、上调PDCD 4、减弱Akt激活和增加线粒体分裂可能导致异丙酚引起的神经毒性。 我们最初的令人兴奋的数据表明，丙泊酚导致干细胞衍生的人类神经元中miR-21的下调。此外，miR-21敲除增加了小鼠发育神经元和人类神经元对丙泊酚暴露的脆弱性。miR-21过表达可减弱丙泊酚诱导的培养人神经元凋亡。此外，miR-21的减少伴随着人类神经元中Akt活化的减少、线粒体分裂的增加和mPTP开放的增加，这强烈支持了我们的假设。我们提出了未来五年的以下具体目标来验证我们的假设：1）检查miR-21在小鼠脑中丙泊酚神经毒性中的作用; 2）确定miR-21在人类神经元中丙泊酚神经毒性中的作用; 3）确定miR-21/PDCD 4/线粒体裂变途径在人类神经元和小鼠脑中丙泊酚神经毒性中的作用。这是一项高度临床相关的研究，具有创新性，处于该领域的前沿。基于这项研究的发现，我们可以制定更合理的神经保护策略，从而在确保儿科人群麻醉安全性方面取得重大进展。