Department of Pharmacology and Toxicology, Brody School of Medicine at East Carolina University, Greenville, NC, 27834, USA.
Department of Anatomy and Cell Biology, Brody School of Medicine at East Carolina University, Greenville, NC, 27834, USA.
Sci Rep. 2021 Apr 30;11(1):9356. doi: 10.1038/s41598-021-88750-2.
The endocannabinoid system (ECS) plays a complex role in the development of neural circuitry during fetal brain development. The cannabinoid receptor type 1 (CB) controls synaptic strength at both excitatory and inhibitory synapses and thus contributes to the balance of excitatory and inhibitory signaling. Imbalances in the ratio of excitatory to inhibitory synapses have been implicated in various neuropsychiatric disorders associated with dysregulated central nervous system development including autism spectrum disorder, epilepsy, and schizophrenia. The role of CB in human brain development has been difficult to study but advances in induced pluripotent stem cell technology have allowed us to model the fetal brain environment. Cortical spheroids resemble the cortex of the dorsal telencephalon during mid-fetal gestation and possess functional synapses, spontaneous activity, an astrocyte population, and pseudo-laminar organization. We first characterized the ECS using STORM microscopy and observed synaptic localization of components similar to that which is observed in the fetal brain. Next, using the CB-selective antagonist SR141716A, we observed an increase in excitatory, and to a lesser extent, inhibitory synaptogenesis as measured by confocal image analysis. Further, CB antagonism increased the variability of spontaneous activity within developing neural networks, as measured by microelectrode array. Overall, we have established that cortical spheroids express ECS components and are thus a useful model for exploring endocannabinoid mediation of childhood neuropsychiatric disease.
内源性大麻素系统 (ECS) 在胎儿大脑发育过程中神经回路的发育中起着复杂的作用。大麻素受体 1 (CB) 控制兴奋性和抑制性突触的突触强度，从而有助于兴奋性和抑制性信号的平衡。兴奋性和抑制性突触比例的失衡与各种与中枢神经系统发育失调相关的神经精神疾病有关，包括自闭症谱系障碍、癫痫和精神分裂症。CB 在人类大脑发育中的作用很难研究，但诱导多能干细胞技术的进步使我们能够模拟胎儿大脑环境。皮质球体类似于中孕期背侧端脑的皮质，具有功能性突触、自发性活动、星形胶质细胞群体和假层状组织。我们首先使用 STORM 显微镜对 ECS 进行了表征，并观察到与胎儿大脑中观察到的类似的突触定位。接下来，使用 CB 选择性拮抗剂 SR141716A，我们观察到兴奋性突触发生增加，并且在通过共聚焦图像分析测量时，抑制性突触发生增加的程度较小。此外，CB 拮抗作用增加了发育中神经网络内自发性活动的可变性，这可以通过微电极阵列来衡量。总的来说，我们已经证实皮质球体表达 ECS 成分，因此是探索内源性大麻素对儿童神经精神疾病的中介作用的有用模型。
