Erythropoietin reshapes the adult hippocampal chromatin landscape to promote neurogenesis

ABSTRACT Understanding the molecular mechanisms by which erythropoietin (EPO) acts as neurotrophic factor that enhances hippocampal function and learning is essential to harness its therapeutic potential. Here, we employ single-nucleus ATAC-seq and RNA-seq to map the epigenomic and transcriptional landscapes of adult mouse hippocampus under recombinant human EPO (rhEPO) treatment. We discover significant lineage-specific chromatin remodeling predominantly in newly formed and immature excitatory neurons, highlighting a robust EPO-driven neurogenic response as the first direct evidence that an extrinsic factor can induce adult hippocampal neurogenesis. Notably, many EPO-induced accessible regions overlap ancient transposable elements, particularly ancient LINEs and SINEs, that are bound by key neurogenic transcription factors such as NEUROD1/2, NEUROG2, FOXG1, and ASCL1 and are linked to nearby genes governing neuronal differentiation and synaptic plasticity. Our findings uncover a previously unrecognized transposon-mediated mechanism underlying EPO-induced neurogenesis, highlighting an underappreciated role for TE-derived sequences in this process, and establish a publicly available single-nucleus multiomic atlas as a resource for understanding cell-type-specific gene regulation and neuroplasticity in the adult brain.