Injury-induced enhancer remodelling in spinal microglia - a novel mechanism for pain chronification? [RNA-Seq]. Mus musculus

Chronic pain is common and devastating. Yet, its precise molecular origins remain unclear. The condition induces well-characterised changes in neurons and microglia, but it is unknown why they persist long after the precipitating injury has healed. We posit a role for enhancers - regions of open chromatin that define a cell’s transcription factor binding profile. Enhancer profiles can alter upon environmental stimulation, functioning as a kind of molecular memory. Here, a mouse model of persistent neuropathic pain was used to examine microglial enhancers with flow cytometry and sequencing. We observed injury-specific alterations of enhancers in close proximity to transcriptionally regulated genes. Our data also shine light on details relating to the spinal cord immune response and provide the first genome-wide gene expression profile of isolated microglia in a pain state. We hypothesise that enhancer deposition may constitute a novel mechanism by which painful experiences are encoded on a molecular level. Overall design: ChIP-seq and RNA-seq of isolated spinal cord microglia after peripheral spinal nerve ligation or sham surgery in mice (day 7)