# Regulation and Function of PlexinA2 Forward Signaling in Persistent Pain > **NIH NIH P20** · ARKANSAS CHILDREN'S HOSPITAL RES INST · 2022 · $269,500 ## Abstract Summary Persistent pain develops following nerve injury when primary sensory neurons show complex, activity- dependent plasticity and ectopic discharges. It is often refractory to existing treatments and associated with adverse health outcomes. The dorsal root ganglion (DRG) is a collection of several types of sensory neuronal cell bodies and satellite glia which acts as the initial point of modulation of action potentials from potentially noxious stimuli to second order spinal cord neurons. Epigenetic variability is known to cause dysregulation of gene transcription which may modulate nociception to alter an individual’s susceptibility for persistent pain. Chromatin accessibility regulates transcription factor binding to cis-regulatory regions and subsequent changes in gene expression. Therefore, understanding how changes in chromatin accessibility at these regulatory regions modulate transcription factor binding in chronic pain states would help to identify regulatory loci in the DRG. Following peripheral nerve injury, regenerative mechanisms are activated to recover lost motor, sensory, and autonomic functions. Neuropathic pain develops when these mechanisms promote maladaptive neural connectivity that becomes electrically hyperexcitable and generates spontaneous and evoked action potentials. How these processes become activated to promote pain in the absence of nerve injury is unknown. We have completed the first comprehensive map of changes in chromatin accessibility with matching RNA- seq in the DRG using two well-studied models of persistent pain – surgical ligation of the sciatic nerve (CCI) and hind paw inflammation (CFA). We identified differential expression of members of the plexin-semaphorin pathway with changes in chromatin accessibility at their putative cis-regulatory regions. This pathway generates attractive or repulsive cues to reunite with its distal, denervated segment. PlexinA2 is a member of a large family of receptors that bind to semaphorin, which then heterodimerizes with Nrp1 to form a functional neuronal receptor that activates Rnd1. The role of PlexinA2, Nrp1 and Rnd1 in persistent pain remains unclear. However, altered Plxna2 expression during development disrupts normal peripheral nervous system morphology. We hypothesize that altered epigenetic regulation of Plxna2, Nrp1 and Rnd1 expression in sensory neurons plays a functional role in axon guidance and promotes persistent pain states. In addition, we hypothesize that changes to the sensory environment during neuronal development may epigenetically prime nociceptors to promote altered nociceptive thresholds later in life. We will pursue the following Specific Aims to test our hypotheses: (1) To determine how chromatin topology affects Plxna2 expression and genes involved in its forward signaling in DRG neurons in neuropathic and inflammatory pain conditions, (2) To understand how modulation of the Plxna2-Nrp1- Rnd1 axis in DRG neurons alters neurite structure and... ## Key facts - **NIH application ID:** 10496405 - **Project number:** 2P20GM121293-06 - **Recipient organization:** ARKANSAS CHILDREN'S HOSPITAL RES INST - **Principal Investigator:** Kimberly E Stephens - **Activity code:** P20 (R01, R21, SBIR, etc.) - **Funding institute:** NIH - **Fiscal year:** 2022 - **Award amount:** $269,500 - **Award type:** 2 - **Project period:** 2017-07-11 → 2027-06-30 ## Primary source NIH RePORTER: https://reporter.nih.gov/project-details/10496405 ## Citation > US National Institutes of Health, RePORTER application 10496405, Regulation and Function of PlexinA2 Forward Signaling in Persistent Pain (2P20GM121293-06). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10496405. Licensed CC0. --- *[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*