Activating Transcription Factor 3 in Pain: A Molecular Regulator and Emerging Biomarker.

Pain is a complex process involving dynamic transcriptional changes in cells of the PNS and CNS following injury or inflammation. Among stress-inducible transcription factors, ATF3 has emerged as one of the most robust molecular markers of neuronal injury, particularly in sensory neurons of the DRG. Although ATF3 is widely used as an indicator of axonal damage in experimental pain models, its functional contribution to the initiation, maintenance, and resolution of pain remains poorly understood. Recent transcriptomic and functional studies suggest that ATF3 not only reflects neuronal stress but also orchestrates gene expression programs involved in axonal regeneration, neuroimmune communication, ion channel remodeling, and nociceptor plasticity. Moreover, ATF3 expression has been identified in non-neuronal cell populations, including Schwann cells and satellite glial cells, indicating broader roles in peripheral nerve repair and neuroinflammation. Despite the growing body of experimental evidence, the literature remains fragmented, and no consensus has yet been reached as to whether ATF3 primarily promotes adaptive regeneration or directly contributes to maladaptive pain signaling. This review aims to provide a comprehensive and critical overview of the current understanding of ATF3 biology in pain, building on evidence from transcriptomic and molecular analyses, experimental models of neuropathic, inflammatory, and cancer-associated pain, and emerging mechanistic insights into its role in pain-related neuronal plasticity. This review examines the regulation of ATF3 expression, its downstream transcriptional targets, its interactions with inflammatory signaling pathways, and its potential value as a therapeutic target. By consolidating current evidence and highlighting existing knowledge gaps, this review seeks to clarify the multifaceted role of ATF3 in pain pathophysiology.