Characterizing Hypoxia-Orchestrated Post-Stroke Changes in Oligodendrocyte Precursor Cells for Improved Stroke Cell Therapy

Oligodendrocyte precursor cells (OPCs) are traditionally known for their role in differentiating into oligodendrocytes, thereby contributing to myelination. Additionally, it has been increasingly recognized that OPCs actively modify their characteristics in response to the surrounding environment, exhibiting various other functions. However, how and when OPCs change their characteristics after acute ischemic stroke, and the contribution of these changes to post-stroke recovery, are not well understood. In this study, we aimed to transcriptionally characterize the changes in OPCs during acute ischemic stroke and develop therapies to support these changes. For this purpose, we first leveraged mouse single-cell RNA sequencing (scRNAseq) datasets to create a “middle cerebral artery occlusion (MCAO) atlas.â€� Crucially, we identified the distinct appearance of “angiogenicâ€� OPCs in the subacute phase and “oligogenicâ€� OPCs in the chronic phase after MCAO, contributing to angiogenesis and remyelination, respectively. Furthermore, we successfully induced OPCs ex vivo with similar functional characteristics to “angiogenicâ€� OPCs through severe hypoxic preconditioning. The intravenous transplantation of these hypoxia-preconditioned OPCs more efficiently promoted post-stroke angiogenesis, reduced infarct size, and improved neurological function after MCAO compared to normally treated OPCs. Finally, we demonstrated that mild hypoxia at least partially contributes to the generation of “oligogenicâ€� OPCs. Therefore, following acute ischemic stroke, OPCs sense oxygen levels and undergo phenotypic changes to exhibit functions required at specific times. Importantly, therapies supporting these phenotypic changes hold great promise for improving recovery from damage caused by acute ischemic stroke, for which current available treatments focus on quickly restoring blood flow.少突胶质前体细胞（Oligodendrocyte precursor cells，OPCs）传统上被认为可分化为少突胶质细胞，进而参与髓鞘形成。此外，越来越多的研究证实，少突胶质前体细胞可响应周围环境主动改变自身特性，展现出多种其他功能。然而，急性缺血性脑卒中（acute ischemic stroke）后，少突胶质前体细胞如何、何时发生特性改变，以及这些改变对卒中后恢复的贡献，目前尚未明确。本研究旨在从转录组层面解析急性缺血性脑卒中过程中少突胶质前体细胞的特性变化，并开发可调控此类变化的治疗策略。为此，我们首先利用小鼠单细胞RNA测序（single-cell RNA sequencing，scRNAseq）数据集构建了"大脑中动脉闭塞（middle cerebral artery occlusion，MCAO）图谱"。关键在于，我们在大脑中动脉闭塞后的亚急性阶段与慢性阶段分别发现了具有独特特征的"血管生成型（angiogenic）"少突胶质前体细胞和"少突胶质生成型（oligogenic）"少突胶质前体细胞，二者分别参与血管生成与髓鞘再生。此外，我们通过重度缺氧预处理，在体外成功诱导出与"血管生成型"少突胶质前体细胞功能特性相似的细胞。与常规培养的少突胶质前体细胞相比，经缺氧预处理的细胞经静脉移植后，可更有效地促进卒中后血管生成、缩小梗死体积，并改善大脑中动脉闭塞模型小鼠的神经功能。最后，我们证实轻度缺氧可至少部分促进"少突胶质生成型"少突胶质前体细胞的生成。因此，急性缺血性脑卒中发生后，少突胶质前体细胞可感知氧分压变化并发生表型改变，以展现特定时段所需的功能。重要的是，可调控此类表型改变的治疗策略，有望改善急性缺血性脑卒中所致损伤的恢复效果——而目前现有治疗手段仅专注于快速恢复脑血流。