DNA damage mediates changes in neuronal sensitivity induced by the inflammatory mediators, MCP-1 and LPS, and can be reversed by enhancing the DNA repair function of APE1. (16th December 2017)

• Record Type: Journal Article
• Authors: Fehrenbacher, Jill C.; Guo, Chunlu; Kelley, Mark R.; Vasko, Michael R.
• Is Part Of: Neuroscience. Volume 366(2017)
• Page Start: 23
• Page End: 35
• Publication Date: 2017-12-16
• Subjects: AP apurinic/apyrimidinic -- APE1/Ref-1 apurinic/apyrimidinic endonuclease 1/redox effector factor 1 -- BER base excision repair -- CCR2 CC chemokine receptor type 2 -- CFA complete Freund's adjuvant -- CGRP calcitonin gene-related peptide -- DRG dorsal root ganglia -- HA Hemagglutinin -- LPS Lipopolysaccharides -- MCP-1/CCL2 monocyte chemoattractant protein-1/ CC chemokine ligand 2 -- MPL methylpyrrolidone -- RNS reactive nitrogen species -- ROS reactive oxygen species -- TLR4 toll-like receptor 4 -- TRPV1 transient receptor potential vanilloid 1; DNA damage -- inflammation -- TRPV1 -- dorsal root ganglia -- apurinic/apyrimidinic endonuclease 1/redox effector factor 1 -- E3330; Neurochemistry -- Periodicals; Neurophysiology -- Periodicals; Neurology -- Periodicals; Neurochimie -- Périodiques; Neurophysiologie -- Périodiques; Neurochemistry; Neurophysiology; Electronic journals; Periodicals; Electronic journals; 612.8
• DOI: 10.1016/j.neuroscience.2017.09.039
• Languages: English
• ISSNs: 0306-4522

Abstract

Highlights: Peripheral inflammation or exposure of sensory neurons to the inflammatory mediators, LPS and MCP-1, elicits DNA damage. Exposure of sensory neuronal cultures to LPS or MCP-1 results in changes in the stimulated release of CGRP. Genetically enhancing APE1 expression or treatment with the small molecule, E3330, increases DNA repair. An increase in DNA repair attenuates DNA damage and the changes in neuronal sensitivity elicited by LPS or MCP-1. Abstract: Although inflammation-induced peripheral sensitization oftentimes resolves as an injury heals, this sensitization can be pathologically maintained and contribute to chronic inflammatory pain. Numerous inflammatory mediators increase the production of reactive oxygen (ROS) and nitrogen species (RNS) during inflammation and in animal models of chronic neuropathic pain. Our previous studies demonstrate that ROS/RNS and subsequent DNA damage mediate changes in neuronal sensitivity induced by anticancer drugs and by ionizing radiation in sensory neurons, thus we investigated whether inflammation and inflammatory mediators also could cause DNA damage in sensory neurons and whether that DNA damage alters neuronal sensitivity. DNA damage was assessed by pH2A.X expression and the release of the neuropeptide, calcitonin gene-related peptide (CGRP), was measured as an index of neuronal sensitivity. Peripheral inflammation or exposure of cultured sensory neurons to the inflammatory mediators, LPS and MCP-1, elicited DNA damage. Moreover, exposure of sensory neuronal cultures to LPS or MCP-1 resulted in changes in the stimulated release of CGRP, without altering resting release or CGRP content. Genetically enhancing the expression of the DNA repair enzyme, apurinic/apyrimidinic endonuclease (APE1) or treatment with a small-molecule modulator of APE1 DNA repair activity, both which enhance DNA repair, attenuated DNA damage and the changes in neuronal sensitivity elicited by LPS or MCP-1. In conclusion, our studies demonstrate that inflammation or exposure to inflammatory mediators elicits DNA damage in sensory neurons. By enhancing DNA repair, we demonstrate that this DNA damage mediates the alteration of neuronal function induced by inflammatory mediators in peptidergic sensory neurons.