Zhang Qiuxiang, Kindt Katie S
Section on Sensory Cell Development and Function, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States.
Front Cell Dev Biol. 2022 Apr 20;10:819612. doi: 10.3389/fcell.2022.819612. eCollection 2022.
Hair cells are the sensory receptors in the auditory and vestibular systems of all vertebrates, and in the lateral-line system of aquatic vertebrates. The purpose of this work is to explore the zebrafish lateral-line system as a model to study and understand spontaneous activity . Our work applies genetically encoded calcium indicators along with light-sheet fluorescence microscopy to visualize spontaneous calcium activity in the developing lateral-line system. Consistent with our previous work, we show that spontaneous calcium activity is present in developing lateral-line hair cells. We now show that supporting cells that surround hair cells, and cholinergic efferent terminals that directly contact hair cells are also spontaneously active. Using two-color functional imaging we demonstrate that spontaneous activity in hair cells does not correlate with activity in either supporting cells or cholinergic terminals. We find that during lateral-line development, hair cells autonomously generate spontaneous events. Using localized calcium indicators, we show that within hair cells, spontaneous calcium activity occurs in two distinct domains-the mechanosensory bundle and the presynapse. Further, spontaneous activity in the mechanosensory bundle ultimately drives spontaneous calcium influx at the presynapse. Comprehensively, our results indicate that in developing lateral-line hair cells, autonomously generated spontaneous activity originates with spontaneous mechanosensory events.
毛细胞是所有脊椎动物听觉和前庭系统以及水生脊椎动物侧线系统中的感觉感受器。这项工作的目的是探索斑马鱼侧线系统作为研究和理解自发活动的模型。我们的工作应用基因编码钙指示剂以及光片荧光显微镜来可视化发育中的侧线系统中的自发钙活动。与我们之前的工作一致，我们表明自发钙活动存在于发育中的侧线毛细胞中。我们现在表明，围绕毛细胞的支持细胞以及直接接触毛细胞的胆碱能传出终末也具有自发活性。使用双色功能成像，我们证明毛细胞中的自发活动与支持细胞或胆碱能终末中的活动无关。我们发现，在侧线发育过程中，毛细胞自主产生自发事件。使用局部钙指示剂，我们表明在毛细胞内，自发钙活动发生在两个不同的区域——机械感觉束和突触前。此外，机械感觉束中的自发活动最终驱动突触前的自发钙内流。综合来看，我们的结果表明，在发育中的侧线毛细胞中，自主产生的自发活动源于自发的机械感觉事件。
