High-Resolution Profiling of Osteocyte Transcriptomes via Single-Nucleus RNA Sequencing

We developed a protocol for snRNA-seq on bone tissue, achieving high-yield recovery of osteocyte nuclei from snap-frozen, marrow-flushed long bones. This approach minimized dissociation bias and enhanced osteocyte representation. We applied this robust method to long bones from young adult male and female mice, generating a high-resolution map of osteocyte gene expression under physiological conditions. Compared to scRNA-seq datasets, where osteocytes represent only 0.18–6.64% of cells, our snRNA-seq approach increased osteocyte capture and transcriptomic fidelity to 18.5%. We identified an osteocyte transcriptomic signature highlighting the top 30 genes, including Sost, which is typically undetected or lowly-expressed in scRNA-seq. Notably, 23 of these genes have not been well-characterized in osteocytes, including Tg, Kcnq5, Rapgef4os1, Cacna1a, Egr3, Dok5, and Lgr6, which may represent novel regulators of osteocyte biology. This study represents the first application of snRNA-seq specifically for osteocyte analysis in bone tissue, providing a valuable resource for investigating osteocyte biology and skeletal disorders.