miRNAs应答同型半胱氨酸代谢变化对人神经细胞Aβ/tau生成与加工路径核心基因表达调控的机制研究

Homocysteine (Hcy) is one of the component in the one carbon metabolism (OCM). Hcy has genomic damage effect and is an independent risk factor for neurodegenerative diseases, cardiovascular and cerebrovascular diseases. Hcy may participate the promoting and development processes of Alzheimer's disease (AD) via mechanisms such as genomic instability (GIN), oxidative stress and inflammation. However, there are many different opinions on the path and mechanism of Hcy's function in the development of AD. As a bridge between microenvironmental change response and gene expression regulation, miRNAs may respond to the changes of Hcy metabolism and mediate the downstream events related AD development. The research will promote from Hcy, with the help of CBMNcyt, sRNA-Seq, miRNA-, RT-qPCR, target gene prediction system, Western Blot and MRI methodological system, to explore the effects of GIN and miRNA profiles of Hcy in human neurocyte in vitro, find the miRNAs targeting the key genes on Aß/tau generation and process, which are the major pathological hallmarks of AD. The research will reveal the development and mechanism of AD mediated by Hcy and miRNAs. As some key components of OCM are responsible to the normal metabolism of Hcy and genome stability maintenance, the project will recruit volunteers following the principles of medical ethics. The effects of peripheral blood Hcy, key components of OCM and related metabolic enzymes polymorphism on GIN and target miRNAs expression will be analyzed, to explore the association between those parameters change and Aβ/tau/brain atrophy status. The research could be much helpful for the discovery of new peripheral tissue hallmarks of AD, providing scientific nutrition support for AD prevention and intervention.

同型半胱氨酸(Hcy)是一碳代谢(OCM)中具基因组损伤效应的组分，是神经退行性和心脑血管疾病独立风险因子，其可能通过基因组不稳定(GIN)、氧化和炎症胁迫影响阿尔兹海默症(AD)风险。Hcy与AD发生发展的可能与机制均无定论。miRNA作为微环境响应与基因表达调控的桥梁，能否应答Hcy代谢改变并介导下游与AD发生发展相关事件？项目以Hcy为起点，探讨Hcy对人神经细胞GIN和miRNA表达谱的影响，挖掘靶向AD主要病理标志—Aβ和tau生成与加工核心基因的目标miRNAs, 解析目标miRNAs对核心基因表达的调控模式，理解Hcy、miRNA介导的AD发生发展机制；基于OCM对Hcy代谢及基因组稳定的维护功能，研究将分析AD志愿者外周血Hcy及OCM关键组分/酶多态性对GIN和目标miRNAs的表达影响，解析它们与Aβ、tau和脑萎缩的关联，为外周组织AD预警、预防与干预提供新的科学依据

同型半胱氨酸(Homocysteine, Hcy)是一碳代谢(one carbon metabolism, OCM)中具基因组损伤效应的非必需含硫氨基酸组分，是神经退行性疾病和心血管疾病的独立风险因子，其可能通过诱发基因组不稳定 (GIN)、氧化和炎症胁迫而影响阿尔兹海默症(AD)风险。miRNA作为微环境响应与基因表达调控的桥梁，能否应答Hcy代谢改变并介导下游与AD发生发展相关事件？项目以Hcy为切入点，借助 CBMNcyt、sRNA-Seq、miRNA 靶基因预测生物信息系统、RT-qPCR、Western Blot和磁共振等技术体系，探讨了Hcy对人神经细胞GIN和miRNA表达谱的影响；分析了靶向AD主要病理标志—Aβ和tau生成与加工核心基因的目标miRNAs, 以及这些miRNAs对核心基因表达的调控模式；探寻了Hcy、miRNA介导的AD发生发展的可能机制；项目基于OCM对Hcy代谢及基因组稳定的维护功能，进一步分析了AD志愿者外周血Hcy及OCM关键组分/酶多态性对外周血淋巴细胞GIN的影响，解析了它们与Aβ、tau和脑萎缩等病理状态的相关性。.研究发现，离体条件下，高浓度Hcy可显著诱发神经细胞基因组损伤，干扰G1/S期检查点，导致细胞阻滞在G0/G1期，该结果为解析Hcy对AD风险的影响提供了新的信息；miR-3940-5p可以从转录和翻译二个层面靶向并抑制Aβ生成限速酶——γ-分泌酶基因PS1的表达，从而间接参与了Aβ42和Aβ40生成负调控，结果为特异性miRNA和其他非编码RNA对AD病理靶标的动态调控、AD风险干预提供了借鉴；研究也为基于Hcy、miRNA介导的AD发生发展及机制、预防与干预提供了新的科学依据和生物标志。人体血浆中的Hcy临床上限浓度（15μmol /L）和离体情况下的神经细胞模型所耐受的Hcy高浓度(100-1000μmol /L)的差异，提示不同组织、不同实验系统中可能存在对Hcy响应与代谢的差异，其意义和价值尚需要进一步探索。