Department of Biosciences, Rice University, Houston, Texas, United States of America.
Biochemistry and Cell Biology Graduate Program, Rice University, Houston, Texas, United States of America.
PLoS One. 2024 Sep 18;19(9):e0310727. doi: 10.1371/journal.pone.0310727. eCollection 2024.
Neural crest cells (NCC) are multipotent migratory stem cells that originate from the neural tube during early vertebrate embryogenesis. NCCs give rise to a variety of cell types within the developing organism, including neurons and glia of the sympathetic nervous system. It has been suggested that failure in correct NCC differentiation leads to several diseases, including neuroblastoma (NB). During normal NCC development, MYCN is transiently expressed to promote NCC migration, and its downregulation precedes neuronal differentiation. Overexpression of MYCN has been linked to high-risk and aggressive NB progression. For this reason, understanding the effect overexpression of this oncogene has on the development of NCC-derived sympathoadrenal progenitors (SAP), which later give rise to sympathetic nerves, will help elucidate the developmental mechanisms that may prime the onset of NB. Here, we found that overexpressing human EGFP-MYCN within SAP lineage cells in zebrafish led to the transient formation of an abnormal SAP population, which displayed expanded and elevated expression of NCC markers while paradoxically also co-expressing SAP and neuronal differentiation markers. The aberrant NCC signature was corroborated with in vivo time-lapse confocal imaging in zebrafish larvae, which revealed transient expansion of sox10 reporter expression in MYCN overexpressing SAPs during the early stages of SAP development. In these aberrant MYCN overexpressing SAP cells, we also found evidence of dampened BMP signaling activity, indicating that BMP signaling disruption occurs following elevated MYCN expression. Furthermore, we discovered that pharmacological inhibition of BMP signaling was sufficient to create an aberrant NCC gene signature in SAP cells, phenocopying MYCN overexpression. Together, our results suggest that MYCN overexpression in SAPs disrupts their differentiation by eliciting abnormal NCC gene expression programs, and dampening BMP signaling response, having developmental implications for the priming of NB in vivo.
神经嵴细胞 (NCC) 是多能迁移干细胞，起源于早期脊椎动物胚胎发生过程中的神经管。NCC 会在发育中的生物体中产生多种细胞类型，包括交感神经系统的神经元和神经胶质细胞。有人提出，NCC 分化的错误会导致多种疾病，包括神经母细胞瘤 (NB)。在正常的 NCC 发育过程中，MYCN 短暂表达以促进 NCC 迁移，其下调先于神经元分化。MYCN 的过表达与高危和侵袭性 NB 的进展有关。因此，了解该致癌基因的过表达对 NCC 衍生的交感肾上腺祖细胞 (SAP) 发育的影响，将有助于阐明可能导致 NB 发病的发育机制。在这里，我们发现，在斑马鱼的 SAP 谱系细胞中过表达人 EGFP-MYCN 会导致异常 SAP 群体的短暂形成，该群体显示出 NCC 标志物的扩展和升高表达，同时也反常地共表达 SAP 和神经元分化标志物。这种异常的 NCC 特征与斑马鱼幼虫体内的实时共聚焦成像相吻合，该成像揭示了在 SAP 发育的早期阶段，过表达 MYCN 的 SAP 中 sox10 报告基因表达的短暂扩展。在这些异常的 MYCN 过表达的 SAP 细胞中，我们还发现了 BMP 信号活性减弱的证据，表明在 MYCN 表达升高后会发生 BMP 信号中断。此外，我们发现 BMP 信号的药理学抑制足以在 SAP 细胞中产生异常的 NCC 基因特征，模拟 MYCN 的过表达。总之，我们的研究结果表明，SAP 中的 MYCN 过表达通过引发异常的 NCC 基因表达程序并减弱 BMP 信号反应，破坏其分化，对体内 NB 的启动具有发育意义。
