Isolation of Oligodendrogial Nuclear RNA from Fresh Frozen Human Brains for Transcriptomic Analysis

Isolation of cell-type-specific RNA from human post-mortem brain tissue is essential for understanding gene regulatory mechanisms underlying normal brain function and neurological disease. However, dissociation of intact cells from frozen brain tissue is technically challenging and often incompatible with archived human samples. Isolation of nuclei provides a robust alternative that preserves nuclear RNA and enables transcriptomic analyses from fresh frozen tissue. Here, we describe a protocol for the isolation of oligodendrocyte lineage-enriched nuclear RNA from fresh frozen human brain tissue. Nuclei are obtained by mechanical homogenization, immunolabeled with antibodies against Olig2 and NeuN, and sorted by fluorescence-activated cell sorting (FACS). RNA is subsequently extracted from sorted nuclei for downstream molecular analyses. This approach enables reliable enrichment of oligodendroglial nuclei while excluding neuronal populations and is suitable for bulk transcriptomic applications using human brain tissue.