1 5935 151 TARGETING GATA1 AND P2X7R LOCUS BINDING IN SPINAL ASTROCYTES SUPPRESSES CHRONIC VISCERAL PAIN BY PROMOTING DNA DEMETHYLATION. IRRITABLE BOWEL SYNDROME IS A GASTROINTESTINAL DISORDER OF UNKNOWN ETIOLOGY CHARACTERIZED BY WIDESPREAD, CHRONIC ABDOMINAL PAIN ASSOCIATED WITH ALTERED BOWEL MOVEMENTS. INCREASING AMOUNTS OF EVIDENCE INDICATE THAT INJURY AND INFLAMMATION DURING THE NEONATAL PERIOD HAVE LONG-TERM EFFECTS ON TISSUE STRUCTURE AND FUNCTION IN THE ADULT THAT MAY PREDISPOSE TO GASTROINTESTINAL DISEASES. IN THIS STUDY WE AIMED TO INVESTIGATE HOW THE EPIGENETIC REGULATION OF DNA DEMETHYLATION OF THE P2X7R LOCUS GUIDED BY THE TRANSCRIPTION FACTOR GATA BINDING PROTEIN 1 (GATA1) IN SPINAL ASTROCYTES AFFECTS CHRONIC VISCERAL PAIN IN ADULT RATS WITH NEONATAL COLONIC INFLAMMATION (NCI). THE SPINAL GATA1 TARGETING TO DNA DEMETHYLATION OF P2X7R LOCUS IN THESE RATS WAS ASSESSED BY ASSESSING GATA1 FUNCTION WITH LUCIFERASE ASSAY, CHROMATIN IMMUNOPRECIPITATION, PATCH CLAMP, AND INTERFERENCE IN VITRO AND IN VIVO. IN ADDITION, A DECOY OLIGODEOXYNUCLEOTIDE WAS DESIGNED AND APPLIED TO DETERMINE THE INFLUENCE OF GATA1 ON THE DNA METHYLATION OF A P2X7R CPG ISLAND. WE SHOWED THAT NCI CAUSED THE INDUCTION OF GATA1, TEN-ELEVEN TRANSLOCATION 3 (TET3), AND PURINERGIC RECEPTORS (P2X7RS) IN ASTROCYTES OF THE SPINAL DORSAL HORN, AND DEMONSTRATED THAT INHIBITING THESE MOLECULES MARKEDLY INCREASED THE PAIN THRESHOLD, INHIBITED THE ACTIVATION OF ASTROCYTES, AND DECREASED THE SPINAL SEPSC FREQUENCY. NCI ALSO MARKEDLY DEMETHYLATED THE P2X7R LOCUS IN A MANNER DEPENDENT ON THE ENHANCEMENT OF BOTH A GATA1-TET3 PHYSICAL INTERACTION AND GATA1 BINDING AT THE P2X7R PROMOTER. IMPORTANTLY, WE SHOWED THAT DEMETHYLATION OF THE P2X7R LOCUS (AND THE ATTENDANT INCREASE IN P2X7R EXPRESSION) WAS REVERSED UPON KNOCKDOWN OF GATA1 OR TET3 EXPRESSION, AND DEMONSTRATED THAT A DECOY OLIGODEOXYNUCLEOTIDE THAT SELECTIVELY BLOCKED THE GATA1 BINDING SITE INCREASED THE METHYLATION OF A CPG ISLAND IN THE P2X7R PROMOTER. THESE RESULTS DEMONSTRATE THAT CHRONIC VISCERAL PAIN IS MEDIATED SYNERGISTICALLY BY GATA1 AND TET3 VIA A DNA-DEMETHYLATION MECHANISM THAT CONTROLS P2X7R TRANSCRIPTION IN SPINAL DORSAL HORN ASTROCYTES, AND PROVIDE A POTENTIAL THERAPEUTIC STRATEGY BY TARGETING GATA1 AND P2X7R LOCUS BINDING. 2022 2 6148 41 THE EXPRESSION OF TRANSCRIPTION FACTORS MECP2 AND CREB IS MODULATED IN INFLAMMATORY PELVIC PAIN. EARLY ACTIVATION OF TRANSCRIPTION FACTORS IS ONE OF THE EPIGENETIC MECHANISMS CONTRIBUTING TO THE INDUCTION AND MAINTENANCE OF CHRONIC PAIN STATES. PREVIOUS STUDIES IDENTIFIED THE CHANGES IN A NUMBER OF NOCICEPTION-RELATED GENES, SUCH AS CALCITONIN GENE-RELATED PEPTIDE (CGRP), SUBSTANCE P (SP), AND BRAIN-DERIVED NEUROTROPIC FACTOR (BDNF) IN THE PELVIC ORGANS AFTER TRANSIENT COLONIC INFLAMMATION. THE GENE AND PROTEIN EXPRESSION OF THESE NEUROPEPTIDES COULD BE MODULATED BY TRANSCRIPTION FACTORS METHYL-CPG-BINDING PROTEIN 2 (MECP2) AND CAMP RESPONSE ELEMENT-BINDING PROTEIN (CREB). IN THIS STUDY, WE AIMED TO EVALUATE TIME-DEPENDENT CHANGES IN THE EXPRESSION LEVELS OF MECP2 AND CREB IN THE LUMBOSACRAL (LS) SPINAL CORD AND SENSORY GANGLIA AFTER INFLAMMATION-INDUCED PELVIC PAIN IN RAT. ADULT SPRAGUE-DAWLEY RATS WERE TREATED WITH 2,4,6-TRINITROBENZENESULFONIC ACID (TNBS) TO INDUCE TRANSIENT COLONIC INFLAMMATION. LS (L6-S2) SPINAL CORD SEGMENTS AND RESPECTIVE DORSAL ROOT GANGLIAS (DRGS) WERE ISOLATED FROM CONTROL AND EXPERIMENTAL ANIMALS AT 1, 2, 6, 24 H AND 3 DAYS POST-TNBS TREATMENT. IMMUNOHISTOCHEMICAL (IHC) LABELING AND WESTERN BLOTTING EXPERIMENTS WERE PERFORMED TO ASSESS THE EXPRESSION OF MECP2, CREB AND THEIR PHOSPHORYLATED FORMS. TOTAL MECP2 EXPRESSION, BUT NOT PHOSPHORYLATED P-MECP2 (PS421MECP2) EXPRESSION WAS DETECTED IN THE CELLS OF THE SPINAL DORSAL HORN UNDER CONTROL CONDITIONS. COLONIC INFLAMMATION TRIGGERED A SIGNIFICANT DECREASE IN THE NUMBER OF MECP2-EXPRESSING NEURONS IN PARALLEL WITH ELEVATED NUMBERS OF PS421MECP2-EXPRESSING CELLS AT 2 H AND 6 H POST-TNBS. THE MAJORITY OF MECP2-POSITIVE CELLS (80 +/- 6%) CO-EXPRESSED CREB. TNBS TREATMENT CAUSED A TRANSIENT UP-REGULATION OF CREB-EXPRESSING CELLS AT 1 H POST-TNBS ONLY. THE NUMBER OF CELLS EXPRESSING PHOSPHORYLATED CREB (PS133CREB) DID NOT CHANGE AT 1 H AND 2 H POST-TNBS, BUT WAS DOWN-REGULATED BY THREE FOLDS AT 6 H POST-TNBS. ANALYSIS OF DRG SECTIONS REVEALED THAT THE NUMBER OF MECP2-POSITIVE NEURONS WAS UP-REGULATED BY TNBS TREATMENT, REACHING THREE-FOLD INCREASE AT 2 H POST-TNBS, AND EIGHT-FOLD INCREASE AT 6 H POST-TNBS (P