Lipid Analysis of 30 000 Individual Rodent Cerebellar Cells Using High-Resolution Mass Spectrometry

Single-cell measurements aid our understanding of chemically heterogeneous systems such as the brain. Lipids are one of the least studied chemical classes, and their cell-to-cell heterogeneity remains largely unexplored. We adapted microscopy-guided single-cell profiling using matrix-assisted laser desorption/ionization ion cyclotron resonance mass spectrometry to profile the lipid composition of over 30 000 individual rat cerebellar cells. We detected 520 lipid features, many of which were found in subsets of cells; Louvain clustering identified 101 distinct groups that can be correlated to neuronal and astrocytic classifications and lipid classes. Overall, the two most common lipids found were [PC(32:0)+H]+ and [PC(34:1)+H]+, which were present within 98.9 and 89.5% of cells, respectively; lipid signals present in + and [PG­(40:2­(OH))+Na]+. These results illustrate the vast lipid heterogeneity found within rodent cerebellar cells and hint at the distinct functional consequences of this heterogeneity.单细胞检测技术有助于深化我们对大脑这类化学异质性系统的认知。脂质是研究程度最低的化学物质类别之一，其细胞间异质性迄今仍未得到充分探索。本研究对基于显微镜引导的基质辅助激光解吸电离-离子回旋共振质谱法（matrix-assisted laser desorption/ionization ion cyclotron resonance mass spectrometry）进行适配优化，以此开展单细胞脂质组分析，对超过30000个大鼠小脑单个细胞的脂质组成进行了表征。本研究共检测到520个脂质特征峰，其中多数仅存在于特定细胞亚群中；通过卢万聚类（Louvain clustering）分析，共识别出101个独立细胞群，这些细胞群可与神经元、星形胶质细胞的分类以及脂质类别建立对应关联。总体而言，丰度最高的两种脂质分别为[PC(32:0)+H]+与[PC(34:1)+H]+，二者分别存在于98.9%和89.5%的细胞中；此外还检测到带正电的[PG(40:2(OH))+Na]+脂质信号。上述结果揭示了啮齿类动物小脑细胞中广泛存在的脂质异质性，并暗示该异质性可能伴随截然不同的功能性后果。