Stem Cells and Regenerative Medicine, UCL Great Ormond Street Institute of Child Health, London, UK.
Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands.
Gastroenterology. 2019 Apr;156(5):1483-1495.e6. doi: 10.1053/j.gastro.2018.12.020. Epub 2019 Jan 2.
BACKGROUND & AIMS: The enteric nervous system (ENS) is the largest branch of the peripheral nervous system, comprising complex networks of neurons and glia, which are present throughout the gastrointestinal tract. Although development of a fully functional ENS is required for gastrointestinal motility, little is known about the ontogeny of ENS function in humans. We studied the development of neuronal subtypes and the emergence of evoked electrical activity in the developing human ENS.
Human fetal gut samples (obtained via the MRC-Wellcome Trust Human Developmental Biology Resource-UK) were characterized by immunohistochemistry, calcium imaging, RNA sequencing, and quantitative real-time polymerase chain reaction analyses.
Human fetal colon samples have dense neuronal networks at the level of the myenteric plexus by embryonic week (EW) 12, with expression of excitatory neurotransmitter and synaptic markers. By contrast, markers of inhibitory neurotransmitters were not observed until EW14. Electrical train stimulation of internodal strands did not evoke activity in the ENS of EW12 or EW14 tissues. However, compound calcium activation was observed at EW16, which was blocked by the addition of 1 μmol/L tetrodotoxin. Expression analyses showed that this activity was coincident with increases in expression of genes encoding proteins involved in neurotransmission and action potential generation.
In analyses of human fetal intestinal samples, we followed development of neuronal diversity, electrical excitability, and network formation in the ENS. These processes are required to establish the functional enteric circuitry. Further studies could increase our understanding of the pathogenesis of a range of congenital enteric neuropathies.
肠神经系统（ENS）是外周神经系统中最大的分支，由遍布胃肠道的神经元和神经胶质组成的复杂网络构成。尽管完整的 ENS 发育对于胃肠道运动是必需的，但人类 ENS 功能的发生机制知之甚少。我们研究了发育中人类 ENS 中神经元亚型的发育和诱发电活动的出现。
通过免疫组织化学、钙成像、RNA 测序和定量实时聚合酶链反应分析，对人胎儿肠道样本（通过 MRC-Wellcome Trust 人类发育生物学资源-英国获得）进行了特征描述。
人胎儿结肠样本在胚胎周（EW）12 时具有密集的肌间神经丛神经元网络，表达兴奋性神经递质和突触标记物。相比之下，直到 EW14 才观察到抑制性神经递质的标志物。电刺激节间束不会引起 EW12 或 EW14 组织 ENS 的活动。然而，在 EW16 观察到复合钙激活，加入 1 μmol/L 河豚毒素可阻断该激活。表达分析表明，这种活性与参与神经传递和动作电位产生的蛋白质编码基因表达的增加同时发生。
在对人胎儿肠道样本的分析中，我们研究了 ENS 中神经元多样性、电兴奋性和网络形成的发育。这些过程是建立功能性肠回路所必需的。进一步的研究可以增加我们对一系列先天性肠神经病发病机制的理解。
