title: Improvement of spinal non-viral IL-10 gene delivery by D-mannose as a transgene adjuvant to control chronic neuropathic pain.
abstract: BACKGROUND
  Peri-spinal subarachnoid (intrathecal; i.t.) injection of non-viral naked plasmid DNA encoding the anti-inflammatory cytokine, IL-10 (pDNA-IL-10) suppresses chronic neuropathic pain in animal models. However, two sequential i.t. pDNA injections are required within a discrete 5 to 72-hour period for prolonged efficacy. Previous reports identified phagocytic immune cells present in the peri-spinal milieu surrounding the i.t injection site that may play a role in transgene uptake resulting in subsequent IL-10 transgene expression.
  
  
  METHODS
  In the present study, we aimed to examine whether factors known to induce pro-phagocytic anti-inflammatory properties of immune cells improve i.t. IL-10 transgene uptake using reduced naked pDNA-IL-10 doses previously determined ineffective. Both the synthetic glucocorticoid, dexamethasone, and the hexose sugar, D-mannose, were factors examined that could optimize i.t. pDNA-IL-10 uptake leading to enduring suppression of neuropathic pain as assessed by light touch sensitivity of the rat hindpaw (allodynia).
  
  
  RESULTS
  Compared to dexamethasone, i.t. mannose pretreatment significantly and dose-dependently prolonged pDNA-IL-10 pain suppressive effects, reduced spinal IL-1β and enhanced spinal and dorsal root ganglia IL-10 immunoreactivity. Macrophages exposed to D-mannose revealed reduced proinflammatory TNF-α, IL-1β, and nitric oxide, and increased IL-10 protein release, while IL-4 revealed no improvement in transgene uptake. Separately, D-mannose dramatically increased pDNA-derived IL-10 protein release in culture supernatants. Lastly, a single i.t. co-injection of mannose with a 25-fold lower pDNA-IL-10 dose produced prolonged pain suppression in neuropathic rats.
  
  
  CONCLUSIONS
  Peri-spinal treatment with D-mannose may optimize naked pDNA-IL-10 transgene uptake for suppression of allodynia, and is a novel approach to tune spinal immune cells toward pro-phagocytic phenotype for improved non-viral gene therapy.
authors.forename: Ellen C
authors.initials: EC
authors.lastname: Dengler
authors.forename: Lauren A
authors.initials: LA
authors.lastname: Alberti
authors.forename: Brandi N
authors.initials: BN
authors.lastname: Bowman
authors.forename: Audra A
authors.initials: AA
authors.lastname: Kerwin
authors.forename: Jenny L
authors.initials: JL
authors.lastname: Wilkerson
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Moezzi
authors.forename: Eugene
authors.initials: E
authors.lastname: Limanovich
authors.forename: James A
authors.initials: JA
authors.lastname: Wallace
authors.affiliation: Department of Neurosciences, UNM School of Medicine, University of New Mexico Health Sciences Center, 1 University of New Mexico, Albuquerque, NM 87131-0001, USA. EMilligan@salud.unm.edu.
authors.forename: Erin D
authors.initials: ED
authors.lastname: Milligan
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D002478:Cells, Cultured; D002908:Chronic Disease; D003251:Constriction, Pathologic / Q000150:complications; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D003907:Dexamethasone / Q000627:therapeutic use; D004195:Disease Models, Animal; D015316:Genetic Therapy; D016753:Interleukin-10 / Q000096:biosynthesis / Q000627:therapeutic use*; D008297:Male; D008358:Mannose / Q000627:therapeutic use*; D051379:Mice; D008850:Microphthalmos / Q000188:drug therapy / Q000378:metabolism; D009437:Neuralgia / Q000209:etiology / Q000628:therapy*; D009569:Nitric Oxide / Q000378:metabolism; D017288:Pain Threshold / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000378:metabolism / Q000502:physiology
chemical_list: D000893:Anti-Inflammatory Agents; D016207:Cytokines; D016753:Interleukin-10; D009569:Nitric Oxide; D003907:Dexamethasone; D008358:Mannose