嗅觉类器官在退行性疾病治疗中的应用以及嗅球神经元逆向分化的研究

Olfaction (the sense of smell) is the main sensory system to contact and recognize the external environment. The olfactory system is composed of olfactory epithelium, olfactory bulb, and olfactory cortex. Olfactory epithelium is restored and regenerated through basal cells. In the olfactory bulb, the precursors constantly generate interneurons. Our previous work showed that Leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5) is expressed in both olfactory epithelium and olfactory bulb. We found that Lgr5 marks basal cells in olfactory epithelium. The olfactory organoid is established in vitro, derived from Lgr5+ olfactory basal cells. Lgr5 also marks terminally differentiated neurons in olfactory bulb, and these cells form spheres through in vitro culture. Based on these data, we plan to use different ways to improve olfactory organoid culture system and elucidate its potential value in cell transplantation-based therapy to some degenerative diseases. Besides, We will also elucidate whether the single Lgr5+ cells in olfactory bulb can form the spheres. After transplantation, the physiological function of these spheres will be explored to show the reverse differentiation of neurons from olfactory bulb. This project will realize the studies on olfactory organogenesis and development in vitro, which provides solid basis for the application of olfactory organoid in the field of translational medicine. The research on reverse differentiation of neurons from olfactory bulb offers reliable source for adult stem cells, supplying theoretical and technical support for personalized treatment.

嗅觉是接触和认知外部世界的主要感官系统之一。嗅觉系统主要由嗅上皮，嗅球和嗅皮层组成。嗅上皮可以通过基底细胞修复后再生。而嗅球中的前体细胞能够分化为中间神经元。前期研究发现，嗅上皮和嗅球中均表达富含亮氨酸重复序列的G蛋白偶联受体5（Lgr5）。我们发现在嗅上皮中Lgr5标记基底细胞，并通过体外培养Lgr5阳性细胞获得类器官。在嗅球中，Lgr5标记神经元，而通过体外培养的嗅球Lgr5阳性细胞能够长成细胞球。在上述结果的基础上，本项目拟通过不同方法完善嗅觉类器官的培养，通过移植到动物疾病模型进一步探索嗅觉类器官在疾病治疗中的应用价值。此外，揭示单个嗅球Lgr5阳性细胞培养成细胞球的过程以阐明嗅球神经元逆向分化的可能性。本项目将实现体外研究嗅觉类器官发生和发育，为其在转化医学领域的应用提供基础。而嗅球神经元逆向分化的实现将为成年干细胞提供可靠的来源，进而为个体化治疗的实施提供了理论依据和技术支持。

嗅觉是接触和认知外部世界的主要感官系统之一，嗅觉感官障碍或丧失会对患者的日常生活造成严重影响。嗅感觉神经元的退化及基底细胞失活是嗅觉障碍的重要致病机制之一，因此通过体外培养嗅上皮基底细胞并诱导分化成神经元是利用细胞移植治疗嗅觉障碍的重要基础。在本项目中，我们通过荧光筛选的Lgr5阳性细胞培养成嗅上皮类器官。添加小分子化合物和生长因子后，类器官中OMP阳性成熟嗅感觉神经元比例增高，表明朝神经元方向定向分化可以在体外被调控。此外，调控Lgr5表达可以影响类器官的增殖和分化。我们的实验结果还表明，在已有的三维培养体系基础上，通过培养体系的优化，我们成功培养出了人源嗅黏膜类器官并实现了向成熟嗅神经元的分化调控。利用这些类器官，我们验证了Notch信号通路在嗅上皮干细胞增殖分化以及衰老对嗅上皮再生影响中的作用，这表明类器官的开发为研究嗅上皮再生和嗅觉相关疾病的发病机制提供了一种方便高效的工具。