Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden.
MRC Centre of Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK.
Stem Cell Reports. 2018 Sep 11;11(3):651-664. doi: 10.1016/j.stemcr.2018.07.014. Epub 2018 Aug 23.
The development of midbrain dopaminergic (mDA) neurons is controlled by multiple morphogens and transcription factors. However, little is known about the role of extracellular matrix proteins in this process. Here we examined the function of roof plate-specific spondins (RSPO1-4) and the floor plate-specific, spondin 1 (SPON1). Only RSPO2 and SPON1 were expressed at high levels during mDA neurogenesis, and the receptor LGR5 was expressed by midbrain floor plate progenitors. Surprisingly, RSPO2, but not SPON1, specifically promoted the differentiation of mDA neuroblasts into mDA neurons in mouse primary cultures and embryonic stem cells (ESCs). In addition, RSPO2 was found to promote not only mDA differentiation, but also mDA neurogenesis in human ESCs. Our results thus uncover an unexpected function of the matricellular protein RSPO2 and suggest an application to improve mDA neurogenesis and differentiation in human stem cell preparations destined to cell replacement therapy or drug discovery for Parkinson disease.
中脑多巴胺能（mDA）神经元的发育受到多种形态发生素和转录因子的控制。然而，关于细胞外基质蛋白在这一过程中的作用知之甚少。在这里，我们研究了屋顶板特异性的 spondin（RSPO1-4）和基板特异性的 spondin1（SPON1）的功能。只有 RSPO2 和 SPON1 在 mDA 神经发生过程中高水平表达，并且中脑神经基板祖细胞表达受体 LGR5。令人惊讶的是，RSPO2 而不是 SPON1 特异性地促进了小鼠原代培养物和胚胎干细胞（ESCs）中 mDA 神经母细胞向 mDA 神经元的分化。此外，发现 RSPO2 不仅促进 mDA 分化，而且促进人 ESC 中的 mDA 神经发生。因此，我们的研究结果揭示了细胞外基质蛋白 RSPO2 的一个意外功能，并提出了一种应用，以改善人类干细胞制剂中的 mDA 神经发生和分化，用于细胞替代治疗或帕金森病的药物发现。
