基于溶酶体功能紊乱探讨大气超细颗粒物（UFP）诱导小鼠认知功能损伤的发生机制

Atmospheric ultrafine particles (UFP) act directly or indirectly on the central nervous system, inducing neuroinflammatory and synaptic plasticity and promoting cognitive impairment. Lysosomal dysfunction may be involved in this process, however, the related functional and molecular mechanisms are lacking. The objective of this study was to investigate whether lysosomal dysfunction were involved in the cognitive impairment caused by UFP (≤200 nm) in the brain through animal exposure model and cell exposure experiments (primary cultured neurons and hippocampal slices). First, in order to clarify cognitive impairment and dose effects induced by UFP, the learning and memory ability, synaptic structure and functional changes and inflammatory factor expressions were detected after UFP exposure. Secondly, in order to elucidate the lysosomal dysfunction induced by UFP, we investigated the varieties of lysosomal membrane integrity, pH, degradation ability, lysosomal-autophagy pathways (phagophore, autophagosome, amphisome and autolysosome) and the related proteins. Finally, the intervention experiments of lysosomal inhibitor were performed to determine the key roles of lysosomal dysfunction on UFP-induced cognitive impairment. Our research not only will provide basic data for scientific evaluation of neurotoxicity of UFP and health risks, but also provide the guidances for developing UFP monitoring data and reducing environmental pollution and human exposure.

大气超细颗粒物（Ultrafine Particles，UFP）直接或间接作用于中枢神经系统，诱导神经炎性和突触可塑性改变，促进认知功能损伤发生。溶酶体功能紊乱可能参与这一过程，但还缺乏功能和调控机制方面的证据。为此本项目收集空气动力学直径≤200 nm的颗粒物，结合动物暴露模型和体外细胞暴露实验（原代神经元和离体海马脑片）：（1）考察暴露后小鼠学习记忆能力、突触结构和功能变化以及神经炎性因子的表达，明确UFP诱导认知损伤效应及其剂量效应关系。（2）考察UFP暴露对溶酶体膜完整性、pH、降解能力、溶酶体自噬途径及相关蛋白的影响，阐明UFP暴露对神经细胞溶酶体结构和功能的扰动作用。（3）结合溶酶体抑制剂干预实验，检测突触可塑性和炎性因子等认知功能损伤指标的改善情况，确定溶酶体功能紊乱调控UFP诱导认知损伤的作用机制。旨在为科学评价UFP的神经毒性及健康防护提供基础数据。

超细颗粒物（PM0.2）可直接或间接作用于中枢神经系统，在颗粒物诱导的神经炎性、突触可塑性改变和认知功能损伤中发挥重要作用。已有研究主要关注颗粒物对神经元的损害，忽视了胶质细胞在其中的关键作用。本研究结合亚急性动物暴露模型和体外原代神经细胞暴露模型（星形胶质细胞、混合胶质和神经元），研究 PM0.2诱导的神经损伤，并深入探讨星形胶质细胞分型和其自噬溶酶体功能紊乱在其中发挥的关键作用。研究一方面发现 PM0.2暴露可导致星形胶质细胞α-突触核蛋白（α-syn）降解失调，同时自噬流、溶酶体丰度、pH值和降解能力出现紊乱。而mTOR抑制剂(PP242)通过核转录因子EB和溶酶体膜蛋白2通路恢复α-syn降解失调。另一方面 PM0.2 暴露可通过激活小胶质细胞，释放肿瘤坏死因子（TNF-α）、白细胞介素（IL-1α）和补体C1q，共同激活星形胶质细胞向A1型分化，A1型星形胶质细胞通过分泌补体C3诱导神经元突触后致密物-95和突触素损害。最后在对PM0.2和PM2.5能谱分析的比较中发现，PM0.2中碳元素的成分达到70%，而在PM2.5中仅为25%左右，提示我们PM0.2中发挥关键作用的组分可能是炭黑。该研究有助于理解PM0.2导致学习记忆障碍的病理机制，为颗粒物的风险评估和健康干预提供新的见解。