During development, different tissues acquire distinct lipotypes that are coupled to tissue function and homeostasis. In the brain, where complex membrane trafficking systems are required for neural function, specific glycerophospholipids, sphingolipids, and cholesterol are highly abundant, and defective lipid metabolism is associated with abnormal neural development and neurodegenerative disease. Notably, the production of specific lipotypes requires appropriate programming of the underlying lipid metabolic machinery during development, but when and how this occurs is unclear. To address this, we used high-resolution MS^ALL lipidomics to generate an extensive time-resolved resource of mouse brain development covering early embryonic and postnatal stages. This revealed a distinct bifurcation in the establishment of the neural lipotype, whereby the canonical lipid biomarkers 22:6-glycerophospholipids and 18:0-sphingolipids begin to be produced in utero, whereas cholesterol attains its characteristic high levels after birth. Using the resource as a reference, we next examined to which extent this can be recapitulated by commonly used protocols for in vitro neuronal differentiation of stem cells. Here, we found that the programming of the lipid metabolic machinery is incomplete and that stem cell-derived cells can only partially acquire a neural lipotype when the cell culture media is supplemented with brain-specific lipid precursors. Altogether, our work provides an extensive lipidomic resource for early mouse brain development and highlights a potential caveat when using stem cell-derived neuronal progenitors for mechanistic studies of lipid biochemistry, membrane biology and biophysics, which nonetheless can be mitigated by further optimizing in vitro differentiation protocols.

中文翻译：

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神经发育过程中脂质型的获得并没有在干细胞衍生的神经元中重现。

在发育过程中，不同的组织获得与组织功能和体内平衡相关的不同的脂型。在大脑中，神经功能需要复杂的膜运输系统，特定的甘油磷脂、鞘脂和胆固醇含量非常丰富，脂质代谢缺陷与神经发育异常和神经退行性疾病有关。值得注意的是，特定脂型的产生需要在发育过程中对潜在的脂质代谢机制进行适当的编程，但这种情况何时以及如何发生尚不清楚。为了解决这个问题，我们使用高分辨率 MS ^ALL脂质组学来生成涵盖早期胚胎和出生后阶段的小鼠大脑发育的广泛时间分辨资源。这揭示了神经脂型建立过程中的明显分歧，典型的脂质生物标志物22:6-甘油磷脂和18:0-鞘脂在子宫内开始产生，而胆固醇在出生后达到其特有的高水平。使用该资源作为参考，我们接下来检查了干细胞体外神经元分化的常用方案可以在多大程度上概括这一点。在这里，我们发现脂质代谢机制的编程是不完整的，并且当细胞培养基补充脑特异性脂质前体时，干细胞衍生的细胞只能部分获得神经脂质型。总而言之，我们的工作为早期小鼠大脑发育提供了广泛的脂质组学资源，并强调了使用干细胞衍生的神经元祖细胞进行脂质生物化学、膜生物学和生物物理学的机制研究时的潜在警告，尽管如此，可以通过进一步优化体外分化来缓解这一问题协议。