异丙酚相关大鼠海马组织microRNA筛选及其功能的研究

Propofol is the most frequently used intravenous sedative anesthetic in clinical anesthesia and ICU, the effect of propofol in central nervous system are still disputing, and the molecular mechanism has not been elucidated. Studies have shown that propofol has a protective effect in brain assaulted by ischemic injury; however, other studies also found propofol has a deleterious effect in the development of newborn neurons and hippocampal related learning and memory. The molecular mechanisms of paradoxical effect of propofol in central nervous system are also unclear. According this, we hypothesis that propofol could cause the changes in microRNA expression levels after it acts on the central nervous system, thereby the change of related microRNA may regulate the expression level of its target genes and proteins which are probably in the neurodevelopmental related pathways, and eventually affect the synaptic plasticity and hippocampal related learning and memory. This study is designed to screen and identify the expression change of microRNA caused by propofol through microRNA arrays gene chip. Based the bioinformatics analysis of the microRNA gene chip data, the study would elucidate the probable molecular mechanisms of the propofol related microRNA in synapse development and hippocampus related learning and memory through molecular biological, immunological, cellular biological, neurobiological techniques in vitro and in vivo. Furthermore, the study would provide a theoretical basis of the effect of propofol in synapse development and hippocampus related learning and memory.

异丙酚是临床麻醉最常用的静脉镇静药物，目前其对神经系统的保护/毒性作用尚存争议，研究发现异丙酚在脑缺血性损伤时具有保护作用，但也有研究发现其可损害新生神经元的发育及学习记忆能力，但具体分子机制尚不清楚。我们前期研究发现异丙酚可提高CREB磷酸化水平而促进大鼠海马成年神经干细胞增殖，预实验亦发现异丙酚可影响突触发育和学习记忆能力，并可影响miR132的表达。因此我们假设异丙酚作用后引起了microRNA表达变化，进而调控相应靶基因和蛋白表达，产生其对突触可塑性和海马相关的学习记忆能力的影响。本课题拟采用microRNA芯片筛选和鉴定大鼠海马组织中异丙酚作用相关microRNA，结合生物信息学技术，在体内、外体系中应用分子生物学、细胞生物学等技术在不同层面上阐明其对突触发育和海马相关学习记忆能力的影响，揭示其作用的新分子机制，为异丙酚影响突触发育和海马相关学习记忆能力的作用提供理论依据。

异丙酚是临床应用最广泛的静脉麻醉药物之一，本研究组前期研究表明异丙酚可影响学习记忆功能，而microRNA亦在调控中枢神经系统发育和功能中具有重要作用，因此明确异丙酚作用后对microRNA表达的影响，阐明异丙酚与microRNA之间的相互关联及异丙酚通过microRNA调控神经发育的作用和机制具有重要的意义。本项目就异丙酚对大鼠海马microRNA表达的影响进行了如下研究：① 应用microArray基因芯片筛选了异丙酚作用后大鼠海马差异表达的microRNA；②对差异表达的microRNA进行了生物信息学分析，并对分析结果进行了相应的验证；③通过干预差异microRNA表达，初步研究了异丙酚在体外对神经干细胞发育的影响。现已获得如下结果：①筛选出异丙酚作用后差异表达的13个microRNA，分析获得了差异表达microRNA及其靶基因的生物功能、差异表达microRNA及其靶基因的相互作用网络以及所涉及信号通路的相互作用网络；②对差异表达microRNA及其靶基因进行了验证，筛选出miR-124、miR-137、miR-214和miR-132共4个microRNA及其靶基因进行后续研究；③明确了异丙酚可通过影响miR-124表达，进而改变SP1表达水平发挥其影响神经干细胞分化的作用。此外，在本项目的资助下，本研究对异丙酚作用后小鼠海马lncRNA和mRNA表达水平情况进行了研究。总之，本项目的意义在于：①筛选异丙酚作用后大鼠海马及神经干细胞差异表达的microRNA表达谱，并在在生物信息分析的基础上，验证了其中部分差异表达的microRNA；②揭示了异丙酚可通过调控miR-124影响转录因子SP1表达，进而影响神经干细胞分化的作用。