title: Allergic Inflammation Leads to Neuropathic Pain via Glial Cell Activation.
abstract: Allergic and atopic disorders have increased over the past few decades and have been associated with neuropsychiatric conditions, such as autism spectrum disorder and asthmatic amyotrophy. Myelitis presenting with neuropathic pain can occur in patients with atopic disorder; however, the relationship between allergic inflammation and neuropathic pain, and the underlying mechanism, remains to be established. We studied whether allergic inflammation affects the spinal nociceptive system. We found that mice with asthma, atopic dermatitis, or atopic diathesis had widespread and significantly more activated microglia and astroglia in the spinal cord than those without atopy, and displayed tactile allodynia. Microarray analysis of isolated microglia revealed a dysregulated phenotype showing upregulation of M1 macrophage markers and downregulation of M2 markers in atopic mice. Among the cell surface protein genes, endothelin receptor type B (EDNRB) was most upregulated. Immunohistochemical analysis revealed that EDNRB expression was enhanced in microglia and astroglia, whereas endothelin-1, an EDNRB ligand, was increased in serum, lungs, and epidermis of atopic mice. No EDNRA expression was found in the spinal cord. Expression of FBJ murine osteosarcoma viral oncogene homolog B was significantly higher in the dorsal horn neurons of asthma mice than nonatopic mice. The EDNRB antagonist BQ788 abolished glial and neural activation and allodynia. We found increased serum endothelin-1 in atopic patients with myelitis and neuropathic pain, and activation of spinal microglia and astroglia with EDNRB upregulation in an autopsied case. These results suggest that allergic inflammation induces diffuse glial activation, influencing the nociceptive system via the EDNRB pathway.
  
  
  
  The prevalence of allergic disorders has markedly increased over the past few decades. Allergic disorders are associated with neuropsychiatric conditions; however, the relationship between allergic inflammation and CNS complications is unknown. A peculiar myelitis presenting with persistent neuropathic pain has been reported in patients with allergic disorders. We studied how atopy exerts substantial influence on the nociceptive system. We found that mice with allergic disorders had severe allodynia with activated astroglia and microglia, and showed marked upregulation of endothelin-1 (ET-1) receptor type B (EDNRB) in the spinal cord. A selective EDNRB antagonist prevented allodynia and glial activation. Our findings suggest a novel mechanism whereby atopy induces glial activation and neuropathic pain via an ET-1/EDNRB pathway.
authors.affiliation: Departments of Neurology and Neurological Therapeutics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan 812-8582.
authors.forename: Ryo
authors.initials: R
authors.lastname: Yamasaki
authors.affiliation: Departments of Neurology and Neurological Therapeutics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan 812-8582.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Fujii
authors.affiliation: Departments of Neurology and Neurological Therapeutics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan 812-8582.
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.affiliation: Departments of Neurology and Neurological Therapeutics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan 812-8582.
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Masaki
authors.affiliation: Department of Molecular Cell Biology and Oral Anatomy, Graduate School of Dental Sciences, Kyushu University, Fukuoka, Japan 812-8582, and.
authors.forename: Mizuho A
authors.initials: MA
authors.lastname: Kido
authors.affiliation: Department of Neuropathology, Institute for Medical Science of Aging, Aichi Medical University, Aichi, Japan 480-1195.
authors.forename: Mari
authors.initials: M
authors.lastname: Yoshida
authors.affiliation: Departments of Neurology and Neurological Therapeutics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan 812-8582.
authors.forename: Takuya
authors.initials: T
authors.lastname: Matsushita
authors.affiliation: Departments of Neurology and Neurological Therapeutics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan 812-8582, kira@neuro.med.kyushu-u.ac.jp.
authors.forename: Jun-Ichi
authors.initials: JI
authors.lastname: Kira
mesh_terms: D000818:Animals; D006969:Hypersensitivity, Immediate / Q000150:complications / Q000276:immunology* / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009437:Neuralgia / Q000209:etiology / Q000276:immunology* / Q000473:pathology; D009457:Neuroglia / Q000276:immunology* / Q000473:pathology; D059225:Nociception; D044023:Receptor, Endothelin B / Q000276:immunology*; D013116:Spinal Cord / Q000276:immunology*
chemical_list: C000602969:EDNRB protein, mouse; D044023:Receptor, Endothelin B
keywords: EDNRB; allergy; astroglia; microglia; neuropathic pain