Lysophosphatidic acid receptor expression identifies a pure population of adult hippocampal stem cells with an immune cell-related transcriptional profile

Lysophosphatidic acid receptor 1 (LPA1) is a phospholipid which has been linked to adult hippocampal neurogenesis and learning deficits. Here we investigated whether LPA acts directly on the hippocampal stem cells and whether LPA1 could be a functional marker for their prospective isolation. Our results reveal that exogenous LPA increases precursor potential in vitro and net neurogenesis in vivo, an effect that is mediated by Akt activation. Using a mouse reporter line, immunohistochemistry and flow cytometry followed by in vitro cell culture, we show that, in contrast to the subventricular zone, neural precursor cells in the adult mouse dentate gyrus express LPA1-GFP. Fluorescence-activated cell sorting for LPA1-GFP in combination with Prominin-1 and epidermal growth factor receptor expression allowed the efficient isolation of a very pure population of hippocampal stem cells. Transcriptional analysis revealed a profile suggesting immune response and cytokine signaling as molecular regulators of adult hippocampal neural stem cells. RNA from cells sorted (FACS) from the dentate gyrus of adult LPA1-GFP (lysophosphatidic acid receptor) reporter mice. Sorting was based on the markers EGFR (Egfr), LPA1 (Lpar1) and Prominin1 (Prom1). From each of 4 replicates, 3 populations (stem cells, progenitor cells, niche cells) were sequenced.溶血磷脂酸受体1（Lysophosphatidic acid receptor 1, LPA1）是一种与成年海马神经发生及学习缺陷相关联的磷脂类物质。本研究探究了溶血磷脂酸（Lysophosphatidic acid, LPA）是否可直接作用于海马干细胞，以及LPA1能否作为其前瞻性分离的功能性标记物。研究结果显示，外源性LPA可在体外提升前体细胞潜能，并在体内促进神经发生，该效应由Akt激活介导。借助小鼠报告基因系、免疫组织化学、流式细胞术结合体外细胞培养手段，我们发现：与侧脑室下区不同，成年小鼠齿状回内的神经前体细胞表达LPA1-GFP。结合Prominin-1与表皮生长因子受体（epidermal growth factor receptor, EGFR）的表达特征，对LPA1-GFP进行荧光激活细胞分选，可高效分离得到纯度极高的海马干细胞群。转录组分析结果显示，其基因表达特征提示免疫应答与细胞因子信号通路可作为成年海马神经干细胞的分子调控因子。本数据集的RNA样本来源于成年LPA1-GFP（溶血磷脂酸受体）报告小鼠齿状回经荧光激活细胞分选（FACS）得到的细胞。分选基于EGFR（Egfr）、LPA1（Lpar1）与Prominin1（Prom1）三种标记物。从4次生物学重复的每一份样本中，均对3类细胞群（干细胞、祖细胞、微环境细胞）进行了测序。