Rabeling A, Goolam M
Department of Human Biology, Faculty of Health Sciences University of Cape Town Cape Town South Africa.
UCT Neuroscience Institute Cape Town South Africa.
FASEB Bioadv. 2025 May 2;7(6):e70012. doi: 10.1096/fba.2024-00216. eCollection 2025 Jun.
Stem cell-based models of embryogenesis have exploded in popularity, resulting in protocols with overlapping use of some reagents and differential use of others. As such, the precise contributions of individual signaling molecules, such as Chiron and BMP4, applied to whole or part of aggregates, and matrices, such as Matrigel, to the development of these models are unknown. Furthermore, the use of these different methods, signaling molecules, and matrices has yet to be directly compared under the same conditions. In this paper, we used a mouse embryonic stem cell aggregate model to compare the use of Chiron and BMP4 signaling as pulses (applied to the whole aggregate) or signaling centers (applied to part of the aggregate) and embedded them in low-percentage Matrigel. Each factor had different effects on morphology, Brachyury protein expression, and lineage commitment, with signaling centers having different effects to pulses. BMP4 as a pulse was shown to drive neural differentiation, while signaling centers resulted in better recapitulation of aspects of anterior-posterior axis formation, with polarization of Brachyury protein and expression of anterior and posterior genes observed. This further elucidates the contributions of Chiron and BMP4 to aggregate development to better inform decisions around experimental conditions for in vitro models of embryonic development.
基于干细胞的胚胎发生模型已大受欢迎，导致一些实验方案中部分试剂的使用重叠，而其他试剂的使用则有所不同。因此，单独的信号分子（如Chiron和BMP4）应用于整个或部分聚集体，以及基质（如基质胶）对这些模型发育的确切作用尚不清楚。此外，这些不同方法、信号分子和基质的使用尚未在相同条件下进行直接比较。在本文中，我们使用小鼠胚胎干细胞聚集体模型，比较了Chiron和BMP4信号作为脉冲（应用于整个聚集体）或信号中心（应用于聚集体的一部分）的使用情况，并将它们嵌入低百分比的基质胶中。每个因素对形态、短尾蛋白表达和谱系定向都有不同影响，信号中心与脉冲的影响不同。结果表明，作为脉冲的BMP4可驱动神经分化，而信号中心能更好地重现前后轴形成的某些方面，观察到短尾蛋白的极化以及前后基因的表达。这进一步阐明了Chiron和BMP4对聚集体发育的作用，以便更好地为围绕胚胎发育体外模型实验条件的决策提供信息。
