tiRNA对迷路损伤后前庭代偿中BDNF表达的调控作用及机制研究

Vertigo is one of the most common functionally-disabling conditions that substantially affects the life and work of people. The incidence of vertigo in the general population has been on the rise year by year. However, etiology of vertigo is unclear and strategies standardization for vertigo therapy is urgent. Studies on plasticity mechanism of central vestibular compensation can provide neurobiological information that helps improve the vertigo treatment and vestibular rehabilitation. Our previous studies preliminarily revealed that the brain-derived neurotrophic factor (BDNF) in MVN and flocculus played a pivotal role in vestibular compensation, and transcriptional factor (YY1) could inhibit the activity of the BDNF promoter. Transcription initiation RNA (tiRNA), a novel group of endogenous small non-coding RNAs, can regulate gene transcription via modulating the binding of YY1 with the loci at the transcription initiation site. On the basis of these findings, we were led to hypothesize that tiRNA might regulate the gene transcription of BDNF by working on the target loci of YY1..This research project, by employing Luciferase reporter gene transcription, chromatin immunoprecipitation, nuclear run-on assay, aims to examine the regulatory effects of YY1 on the expression of BDNF promoter and histone modification, and by using RNA and chromatin immunoprecipitation to observe the interaction between tiRNA and YY1 and its features. By constructing a stable system of tiRNA overexpression and inhibition, we will further study the effect of tiRNA expression on the growth, apoptosis, synapse formation and vestibular compensation, with an attempt to understand how tiRNA promote vestibular compensation by modulating the gene transcription of BDNF via YY1 and to find better strategies for vertigo therapy.

前庭中枢的代偿对眩晕的治疗康复和病后平衡状态至关重要。我们前期研究发现：BDNF/TrkB通路是前庭代偿的关键枢纽；但BDNF表达的上游调控机制却不明。转录起始RNA（tiRNA）是新发现的内源性小非编码RNA，能影响转录因子YY1与转录起始位点结合，调控基因转录。我们前期实验和生物信息学分析示：BDNF基因启动子区存在YY1结合位点；tiRNA能靶向结合YY1位点。据此我们提出假说：小脑-前庭通路中tiRNA抑制YY1结合到BDNF的启动子区，改变染色质立体构象，激活基因转录，最终促进前庭代偿。本课题拟从分子、细胞、组织及动物水平多层次体系明确tiRNA在前庭代偿中的作用；确定tiRNA对BDNF基因转录的调控；揭示tiRNA通过YY1介导BDNF/TrkB通路促进前庭代偿的精细机制。本研究将从tiRNA新视角深入探讨前庭代偿的中枢可塑性，为眩晕治疗及前庭康提供新的理论基础和策略。

前庭代偿过程是中枢神经系统对双侧不对称的前庭传入冲动产生的适应，是发生于小脑和脑干水平的、复杂的神经元和神经化学反应过程。前庭代偿机制尚不明确，探究其机制有助于前庭疾病的治疗和康复。我们课题组围绕前庭代偿机制的研究，采用分子生物学、免疫组织化学、神经药理学、分子遗传学及行为学的方式，通过构建不同时间进程的单侧迷路切除术（UL）大鼠模型，探究了LncRNA-mRNA表达谱在前庭代偿分子机制中的潜在作用。另外，我们发现前庭小脑通路中不同类型UBC（unipolar brush cells，单极刷细胞，位于前庭小脑颗粒细胞层中谷氨酸能中级神经元）参与前庭代偿，并完成了机制的初步探究。在项目实施过程中，对研究方案及研究内容进行了相应调整，使得我们的研究更加贴近临床并服务于临床。本项目共资助发表了SCI论文14篇，中文核心期刊论文3篇，制定专家共识4篇。项目研究成果对临床上前庭疾病的诊疗以及康复具有一定的指导意义。