Department of Biomedical Engineering, University of California-Davis, Davis, CA 95616, USA.
Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616, USA.
Biosensors (Basel). 2023 May 31;13(6):601. doi: 10.3390/bios13060601.
The gut-brain axis embodies the bi-directional communication between the gastrointestinal tract and the central nervous system (CNS), where vagal afferent neurons (VANs) serve as sensors for a variety of gut-derived signals. The gut is colonized by a large and diverse population of microorganisms that communicate via small (effector) molecules, which also act on the VAN terminals situated in the gut viscera and consequently influence many CNS processes. However, the convoluted in vivo environment makes it difficult to study the causative impact of the effector molecules on VAN activation or desensitization. Here, we report on a VAN culture and its proof-of-principle demonstration as a cell-based sensor to monitor the influence of gastrointestinal effector molecules on neuronal behavior. We initially compared the effect of surface coatings (poly-L-lysine vs. Matrigel) and culture media composition (serum vs. growth factor supplement) on neurite growth as a surrogate of VAN regeneration following tissue harvesting, where the Matrigel coating, but not the media composition, played a significant role in the increased neurite growth. We then used both live-cell calcium imaging and extracellular electrophysiological recordings to show that the VANs responded to classical effector molecules of endogenous and exogenous origin (cholecystokinin serotonin and capsaicin) in a complex fashion. We expect this study to enable platforms for screening various effector molecules and their influence on VAN activity, assessed by their information-rich electrophysiological fingerprints.
肠脑轴体现了胃肠道和中枢神经系统（CNS）之间的双向通讯，其中迷走传入神经元（VAN）作为各种肠道来源信号的传感器。肠道被大量多样的微生物定植，这些微生物通过小分子（效应分子）进行通讯，这些小分子也作用于位于肠道内脏的 VAN 末梢，从而影响许多中枢神经系统过程。然而，复杂的体内环境使得研究效应分子对 VAN 激活或脱敏的因果影响变得困难。在这里，我们报告了 VAN 培养及其作为基于细胞的传感器的原理验证，用于监测胃肠道效应分子对神经元行为的影响。我们最初比较了表面涂层（多聚赖氨酸与 Matrigel）和培养基组成（血清与生长因子补充）对神经突生长的影响，作为组织收获后 VAN 再生的替代指标，其中 Matrigel 涂层而不是培养基组成在增加的神经突生长中起重要作用。然后，我们使用活细胞钙成像和细胞外电生理记录来显示 VAN 以复杂的方式对内源性和外源性的经典效应分子（胆囊收缩素、血清素和辣椒素）作出反应。我们期望这项研究能够为筛选各种效应分子及其对 VAN 活性的影响提供平台，通过其信息丰富的电生理指纹进行评估。
