How do Olfactory Reserve Stem Cells Differentiate into Neuronal Cells? – A Combined in vitro/in vivo Approach

嗅觉储备干细胞如何分化为神经元细胞？

• 批准号: 504647467
• 负责人: Dr. Constantin Hintschich
• 金额: --
• 依托单位: Massachusetts Eye and Ear
• 依托单位国家: 德国
• 项目类别: WBP Fellowship
• 财政年份: 2022
• 资助国家: 德国
• 起止时间: 2021-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/504647467?language=en
• 关键词: How; do; Olfactory; Reserve; Stem

Age-related olfactory dysfunction affects up to 70% of the population over the age of 80 years. The olfactory epithelium has a distinctive potential to regenerate due to two kinds of stem cells: (1) Globose basal cells which are the first level of regeneration and undergo constant neurogenesis to renew the olfactory epithelium, and (2) horizontal basal cells which are dormant reserve stem cells and only activated in severe damage of the olfactory epithelium. In presbyosmia, the loss of olfactory sensory neurons and globose basal cells leads to a neurogenic exhaustion. However, the population of dormant horizontal basal cells fails to activate. Hence, the deliberate activation of horizontal basal cells in situ is an attractive therapeutic goal in age-related olfactory dysfunction. Previous studies have showed that horizontal basal cells can be activated by downregulation of the transcription factor p63. This can be achieved by the exogenous administration of retinoic acid. However, even after successful activation, the activated HBCs can adopt four different fates. Of them, only one leads to neuronal differentiation into globose basal cells and olfactory neuronal cells. Thus, this therapeutic approach to activate horizontal basal cells also necessitates driving the stem cell reserve toward a neuronal lineage. The underlying mechanisms of the subsequent neuronal differentiation into globose basal cells and olfactory neuronal cells are still largely elusive. This should be elucidated in the following combined in vitro/in vivo approach: First, the effect of different factors on the differentiation will be assessed in cultured murine horizontal basal cells using immunohistochemistry. In a second step this neurogenically differentiated olfactory tissue will be transplanted into a murine host olfactory epithelium. The outcome will also be assessed using immunohistochemistry, too. The aim is to establish optimal culture conditions to regenerate olfactory epithelium in vitro which then can be transplanted into a damaged host olfactory epithelium.

与年龄相关的嗅觉障碍影响着高达70%的80岁以上的人口。由于两种干细胞的存在，嗅觉上皮具有明显的再生潜能：(1)球形基底细胞，它是嗅觉上皮再生的第一级细胞，不断地进行神经再生；(2)水平基底细胞，它是休眠的储备干细胞，只有在嗅觉上皮严重损伤时才被激活。在老年性嗅觉障碍中，嗅觉感觉神经元和球状基底细胞的丧失会导致神经源性疲惫。然而，处于休眠状态的水平基底细胞群不能被激活。因此，有意识地在原位激活水平基底细胞是治疗老年性嗅觉功能障碍的一个有吸引力的目标。先前的研究表明，水平基底细胞可以通过下调转录因子p63来激活。这可以通过外源性给予维甲酸来实现。然而，即使在成功激活后，激活的HBCs也可能有四种不同的命运。其中，只有一种能诱导神经元分化为球状基底细胞和嗅神经细胞。因此，这种激活水平基底细胞的治疗方法也需要将干细胞储备推向神经元谱系。随后神经元分化为球状基底细胞和嗅神经细胞的潜在机制在很大程度上仍然难以捉摸。首先，用免疫组织化学方法研究不同因素对培养的小鼠水平基底细胞分化的影响。在第二步中，这种神经分化的嗅觉组织将被移植到小鼠的宿主嗅觉上皮中。结果也将通过免疫组织化学进行评估。目的是建立在体外再生嗅上皮的最佳培养条件，然后将其移植到受损的宿主嗅上皮中。