基于单细胞测序研究特异神经细胞亚群中ATG4B的亚硝基化修饰及其在衰老中的作用

衰老相关的认知功能障碍严重降低老年人的生活质量，研究其发病机制和开发有效的治疗方法意义重大。NO的产生和自噬缺陷是脑衰老的两个重要致病因素，但之前在群体细胞水平开展的抗氧化治疗策略没有取得理想的效果。单细胞RNA测序表明不同的神经细胞亚群在衰老过程中可能表现出不同的功能状态，即NO和自噬水平的变化可能只发生在特异的亚群中，因此鉴定该特异神经细胞亚群是提供更有效的治疗策略的基础。我们的前期研究发现衰老过程中ATG4B的亚硝基化修饰水平增加，进而可以降低神经细胞中的自噬水平。基于此，本项目将利用小鼠自然衰老模型，采用单细胞RNA测序技术，鉴定NO、ATG4B的亚硝基化修饰和自噬水平发生变化的特异神经细胞亚群；通过腺相关病毒特异性地在该亚群中阻断ATG4B的亚硝基化修饰而挽回认知功能。该研究可揭示衰老的新机制，提供安全有效的治疗策略，同时提供一个新的治疗靶点。

Aging related cognitive dysfunction seriously reduces the quality of life of the elderly, so it is of great significance to study its pathogenesis and develop effective treatment methods. The excess production of NO and autophagy impairment have been viewed as the leading risk factors for cognitive impairment, but previous antioxidant treatment strategies at the bulk cells have not achieved ideal results. Single-cell RNA sequencing indicated that different neuronal sub-population may exhibit different functional states during the aging process, that is, changes in the level of NO and autophagy may only occur in specific sub-population. So the identification of this specific neuronal sub-population is the basis for providing more effective treatment strategies. Our previous work showed that the excessive production of NO in the aging hippocampal tissue resulted in the S-nitrosation of the core autophagy protein ATG4B, while ATG4B S-nitrosation could reduce autophagy in neurons in vitro. Based on this findings, this project will use the single-cell RNA sequencing technology to identify neuron sub-population with changed level of NO and autophagy in the hippocampus of natural aging mice, and specifically block ATG4B S-nitrosation in this neuron sub-population by adeno-associated virus to rescue cognitive function. This study could reveal new mechanisms of aging, provide safe and effective treatment strategies and provide a new therapeutic target.