2. Academic Validation
  3. Activation of GPR183 by 7 α,25-Dihydroxycholesterol Induces Behavioral Hypersensitivity through Mitogen-Activated Protein Kinase and Nuclear Factor- κ B

Activation of GPR183 by 7 α,25-Dihydroxycholesterol Induces Behavioral Hypersensitivity through Mitogen-Activated Protein Kinase and Nuclear Factor- κ B

  • J Pharmacol Exp Ther. 2022 Nov;383(2):172-181. doi: 10.1124/jpet.122.001283.
Kathryn Braden 1,  Michela Campolo 1,  Ying Li 1,  Zhoumou Chen 1,  Timothy M Doyle 1,  Luigino Antonio Giancotti 1,  Emanuela Esposito 1,  Jinsong Zhang 1,  Salvatore Cuzzocrea 1,  Christopher Kent Arnatt 1,  Daniela Salvemini 2
Affiliations

Affiliations

  • 1 Department of Pharmacology and Physiology, Saint Louis University School of Medicine, Saint Louis, Missouri (K.B., Y.L., Z.C., T.M.D., L.A.G., J.Z., C.K.A., D.S.); Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University, Saint Louis, Missouri (K.B., Y.L., Z.C., T.M.D., L.A.G., J.Z., C.K.A.,D.S.); Department of Clinical and Experimental Medicine and Pharmacology, University of Messina, Messina, Italy (M.C., E.E., S.C.); and Department of Chemistry, Saint Louis University, Saint Louis, Missouri (C.K.A.).
  • 2 Department of Pharmacology and Physiology, Saint Louis University School of Medicine, Saint Louis, Missouri (K.B., Y.L., Z.C., T.M.D., L.A.G., J.Z., C.K.A., D.S.); Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University, Saint Louis, Missouri (K.B., Y.L., Z.C., T.M.D., L.A.G., J.Z., C.K.A.,D.S.); Department of Clinical and Experimental Medicine and Pharmacology, University of Messina, Messina, Italy (M.C., E.E., S.C.); and Department of Chemistry, Saint Louis University, Saint Louis, Missouri (C.K.A.) daniela.salvemini@health.slu.edu.
PMID: 36116795 DOI: 10.1124/jpet.122.001283
Abstract

Emerging evidence implicates the G-protein coupled receptor (GPCR) GPR183 in the development of neuropathic pain. Further investigation of the signaling pathways downstream of GPR183 is needed to support the development of GPR183 antagonists as analgesics. In rodents, intrathecal injection of its ligand, 7α,25-dihydroxycholesterol (7α,25-OHC), causes time-dependent development of mechano-and cold- allodynia (behavioral hypersensitivity). These effects are blocked by the selective small molecule GPR183 antagonist, SAE-14. However, the molecular mechanisms engaged downstream of GPR183 in the spinal cord are not known. Here, we show that 7α,25-OHC-induced behavioral hypersensitivity is Gα i dependent, but not β-arrestin 2-dependent. Non-biased transcriptomic analyses of dorsal-horn spinal cord (DH-SC) tissues harvested at the time of peak hypersensitivity implicate potential contributions of mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB). In support, we found that the development of 7α,25-OHC/GPR183-induced mechano-allodynia was associated with significant activation of MAPKs (extracellular signal-regulated kinase [ERK], p38) and redox-sensitive transcription factors (NF-κB) and increased formation of inflammatory and neuroexcitatory cytokines. SAE-14 blocked these effects and behavioral hypersensitivity. Our findings provide novel mechanistic insight into how GPR183 signaling in the spinal cord produces hypersensitivity through MAPK and NF-κB activation. SIGNIFICANCE STATEMENT: Using a multi-disciplinary approach, we have characterized the molecular mechanisms underpinning 7α,25-OHC/GPR183-induced hypersensitivity in mice. Intrathecal injections of the GPR183 agonist 7α,25-OHC induce behavioral hypersensitivity, and these effects are blocked by the selective GPR183 antagonist SAE-14. We found that 7α,25-OHC-induced allodynia is dependent on MAPK and NF-κB signaling pathways and results in an increase in pro-inflammatory cytokine expression. This study provides a first insight into how GPR183 signaling in the spinal cord is pronociceptive.

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