Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Universidad de Valparaíso, Valparaíso, Chile.
Instituto de Neurociencia, Universidad de Valparaíso, Valparaíso, Chile.
Front Immunol. 2022 May 27;13:881702. doi: 10.3389/fimmu.2022.881702. eCollection 2022.
In the vertebrate olfactory tract new neurons are continuously produced throughout life. It is widely believed that neurogenesis contributes to learning and memory and can be regulated by immune signaling molecules. Proteins originally identified in the immune system have subsequently been localized to the developing and adult nervous system. Previously, we have shown that olfactory imprinting, a specific type of long-term memory, is correlated with a transcriptional response in the olfactory organs that include up-regulation of genes associated with the immune system. To better understand the immune architecture of the olfactory organs we made use of cell-specific fluorescent reporter lines in dissected, intact adult brains of zebrafish to examine the association of the olfactory sensory neurons with neutrophils and blood-lymphatic vasculature. Surprisingly, the olfactory organs contained the only neutrophil populations observed in the brain; these neutrophils were localized in the neural epithelia and were associated with the extensive blood vasculature of the olfactory organs. Damage to the olfactory epithelia resulted in a rapid increase of neutrophils both within the olfactory organs as well as the central nervous system. Analysis of cell division during and after damage showed an increase in BrdU labeling in the neural epithelia and a subset of the neutrophils. Our results reveal a unique population of neutrophils in the olfactory organs that are associated with both the olfactory epithelia and the lymphatic vasculature suggesting a dual olfactory-immune function for this unique sensory system.
在脊椎动物的嗅觉径路上，新的神经元在整个生命过程中持续产生。人们普遍认为神经发生有助于学习和记忆，并且可以通过免疫信号分子来调节。最初在免疫系统中鉴定出的蛋白质随后被定位到发育和成年神经系统中。以前，我们已经表明，嗅觉印迹，一种特定类型的长期记忆，与嗅觉器官中的转录反应相关，其中包括与免疫系统相关的基因的上调。为了更好地了解嗅觉器官的免疫结构，我们利用分离的、完整的成年斑马鱼大脑中的细胞特异性荧光报告系，检查嗅觉感觉神经元与中性粒细胞和血液淋巴脉管系统的关联。令人惊讶的是，嗅觉器官包含了在大脑中观察到的唯一的中性粒细胞群体;这些中性粒细胞定位于神经上皮，与嗅觉器官广泛的血管系统有关。嗅上皮损伤导致嗅上皮内和中枢神经系统内的中性粒细胞迅速增加。损伤过程中和损伤后的细胞分裂分析显示，神经上皮和一部分中性粒细胞中的 BrdU 标记增加。我们的结果揭示了嗅觉器官中存在一种独特的中性粒细胞群体，它们与嗅觉上皮和淋巴脉管系统都有关联，这表明这个独特的感觉系统具有双重嗅觉-免疫功能。
