Yi Kevin R, Nash Jac-Leen S S, Carter Mark G, Walkley Danica M, Jang Jiwon, Smagghe Benoit J, Stewart Andrew K, Bamdad Cynthia C
Minerva Biotechnologies, Waltham, Massachusetts, United States of America.
Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea.
PLoS One. 2025 Jun 25;20(6):e0325997. doi: 10.1371/journal.pone.0325997. eCollection 2025.
The literature is replete with conflicting reports as to whether the Wnt/β-catenin pathway induces human stem cell differentiation or pluripotency. Recently, scientists showed that human stem cells expressing low levels of active β-catenin preferentially differentiate down a neuroectoderm lineage, whereas cells expressing high levels favor mesendoderm. However, these results appear to contradict two other studies, where researchers improved differentiation to both neuroectoderm and mesoderm by increasing levels of active β-catenin at the start of differentiation. Here, we show that stem cells cultured with naïve growth factor, NME7AB, express the highest levels of active β-catenin, yet readily differentiate into neuroectoderm and mesendoderm, without lineage preference. This raised the interesting question of whether activation of the Wnt/β-catenin pathway could itself play a role in maintaining or inducing a naïve-like state. The β-catenin agonist WNT3A was added to stem cells in the absence of any other growth factors, which induced the concurrent emergence of two segregated populations: an OCT4+, XaXa naïve-like population and an OCT4- population. This finding could explain the apparently inconsistent reports as to whether β-catenin induces pluripotency or differentiation, while raising additional questions. Notably, does the naïve-like sub-population, devoid of cell fate decisions, contribute to an increased differentiation potential? Conversely, are the OCT4- cells predisposed to differentiate more efficiently? To address these questions, we compared the differentiation of primed state stem cells, with or without pre-treatment with WNT3A, to that of naïve state stem cells. WNT3A pre-treatment improved the differentiation potential of primed stem cells, while having no effect in naïve stem cells. Furthermore, differentiation of the homogeneous population of naïve cells was superior to the primed state cells, even after WNT3A pre-treatment. This result is consistent with the idea that the improved differentiation is due to the sub-population of the WNT3A induced naïve-like cells.
关于Wnt/β-连环蛋白信号通路是诱导人类干细胞分化还是多能性，文献中充斥着相互矛盾的报道。最近，科学家们发现，表达低水平活性β-连环蛋白的人类干细胞优先分化为神经外胚层谱系，而表达高水平活性β-连环蛋白的细胞则倾向于中内胚层。然而，这些结果似乎与另外两项研究相矛盾，在这两项研究中，研究人员通过在分化开始时增加活性β-连环蛋白的水平，改善了向神经外胚层和中胚层的分化。在此，我们表明，用原始生长因子NME7AB培养的干细胞表达最高水平的活性β-连环蛋白，但能轻易分化为神经外胚层和中内胚层，且无谱系偏好。这就引出了一个有趣的问题，即Wnt/β-连环蛋白信号通路的激活本身是否能在维持或诱导原始样状态中发挥作用。在没有任何其他生长因子的情况下，将β-连环蛋白激动剂WNT3A添加到干细胞中，这诱导了两个分离群体的同时出现：一个OCT4+、XaXa原始样群体和一个OCT4-群体。这一发现可以解释关于β-连环蛋白是诱导多能性还是分化的明显不一致的报道，同时也引发了其他问题。值得注意的是，缺乏细胞命运决定的原始样亚群是否有助于增加分化潜能？相反，OCT4-细胞是否更容易更有效地分化？为了解决这些问题，我们比较了经WNT3A预处理或未经预处理的预分化状态干细胞与原始状态干细胞的分化情况。WNT3A预处理提高了预分化干细胞的分化潜能，而对原始干细胞没有影响。此外，即使经过WNT3A预处理，原始细胞的均匀群体的分化也优于预分化状态细胞。这一结果与以下观点一致，即分化的改善是由于WNT3A诱导的原始样细胞亚群所致。
