Investigations into brain function and disease depend on the precise classification of neural cell types. Cells of the oligodendrocyte lineage differ greatly in their morphology, but accurate identification has thus far only been possible for oligodendrocyte progenitor cells and mature oligodendrocytes in humans. We find that breast carcinoma amplified sequence 1 (BCAS1) expression identifies an oligodendroglial subpopulation in the mouse and human brain. These cells are newly formed, myelinating oligodendrocytes that segregate from oligodendrocyte progenitor cells and mature oligodendrocytes and mark regions of active myelin formation in development and in the adult. We find that BCAS1⁺ oligodendrocytes are restricted to the fetal and early postnatal human white matter but remain in the cortical gray matter until old age. BCAS1⁺ oligodendrocytes are reformed after experimental demyelination and found in a proportion of chronic white matter lesions of patients with multiple sclerosis (MS) even in a subset of patients with advanced disease. Our work identifies a means to map ongoing myelin formation in health and disease and presents a potential cellular target for remyelination therapies in MS.

对脑功能和疾病的研究取决于神经细胞类型的精确分类。少突胶质细胞谱系的细胞在形态上有很大差异，但是迄今为止，只有人类的少突胶质细胞祖细胞和成熟的少突胶质细胞才能进行准确鉴定。我们发现，乳腺癌扩增序列1（BCAS1）表达在小鼠和人脑中鉴定出少突胶质细胞亚群。这些细胞是新形成的，有髓鞘的少突胶质细胞，它们与少突胶质细胞祖细胞和成熟的少突胶质细胞分离，并标记发育中和成年中活跃的髓鞘形成区域。我们发现BCAS1 ⁺少突胶质细胞仅限于胎儿和出生后的早期人类白质，但保留在皮质灰质中直至老年。经过实验性脱髓鞘后，BCAS1 ⁺少突胶质细胞得以重建，甚至在部分晚期疾病患者中，在多发性硬化症（MS）患者的一定比例的慢性白质病变中也能发现。我们的工作确定了一种在健康和疾病中定位正在进行的髓磷脂形成的方法，并提出了MS中髓鞘再生治疗的潜在细胞靶标。