title: Intraneural GJB1 gene delivery improves nerve pathology in a model of X-linked Charcot-Marie-Tooth disease.
abstract: OBJECTIVE
  X-linked Charcot-Marie-Tooth disease (CMT1X) is a common inherited neuropathy caused by mutations in the GJB1 gene encoding the gap junction protein connexin32 (Cx32). Clinical studies and disease models indicate that neuropathy mainly results from Schwann cell autonomous, loss-of-function mechanisms; therefore, CMT1X may be treatable by gene replacement.
  
  
  METHODS
  A lentiviral vector LV.Mpz-GJB1 carrying the GJB1 gene under the Schwann cell-specific myelin protein zero (Mpz) promoter was generated and delivered into the mouse sciatic nerve by a single injection immediately distal to the sciatic notch. Enhanced green fluorescent protein (EGFP) reporter gene expression was quantified and Cx32 expression was examined on a Cx32 knockout (KO) background. A gene therapy trial was performed in a Cx32 KO model of CMT1X.
  
  
  RESULTS
  EGFP was expressed throughout the length of the sciatic nerve in up to 50% of Schwann cells starting 2 weeks after injection and remaining stable for up to 16 weeks. Following LV.Mpz-GJB1 injection into Cx32 KO nerves, we detected Cx32 expression and correct localization in non-compact myelin areas where gap junctions are normally formed. Gene therapy trial by intraneural injection in groups of 2-month-old Cx32 KO mice, before demyelination onset, significantly reduced the ratio of abnormally myelinated fibers (p = 0.00148) and secondary inflammation (p = 0.0178) at 6 months of age compared to mock-treated animals.
  
  
  CONCLUSIONS
  Gene delivery using a lentiviral vector leads to efficient gene expression specifically in Schwann cells. Restoration of Cx32 expression ameliorates nerve pathology in a disease model and provides a promising approach for future treatments of CMT1X and other inherited neuropathies.
authors.affiliation: Neuroscience Laboratory.
authors.forename: Irene
authors.initials: I
authors.lastname: Sargiannidou
authors.affiliation: Neuroscience Laboratory.
authors.forename: Alexia
authors.initials: A
authors.lastname: Kagiava
authors.affiliation: Department of Molecular Virology, Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus.
authors.forename: Stavros
authors.initials: S
authors.lastname: Bashiardes
authors.affiliation: Department of Molecular Virology, Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus.
authors.forename: Jan
authors.initials: J
authors.lastname: Richter
authors.affiliation: Department of Molecular Virology, Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus.
authors.forename: Christina
authors.initials: C
authors.lastname: Christodoulou
authors.affiliation: Department of Neurology, University of Pennsylvania, Philadelphia, PA.
authors.forename: Steven S
authors.initials: SS
authors.lastname: Scherer
authors.affiliation: Neuroscience Laboratory.|Neurology Clinics, Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus.
authors.forename: Kleopas A
authors.initials: KA
authors.lastname: Kleopa
mesh_terms: D000818:Animals; D002607:Charcot-Marie-Tooth Disease / Q000235:genetics* / Q000378:metabolism; D017630:Connexins / Q000235:genetics*; D004195:Disease Models, Animal; D015316:Genetic Therapy; D005822:Genetic Vectors; D016086:Lentivirus; D051379:Mice; D018345:Mice, Knockout; D012333:RNA, Messenger / Q000378:metabolism*; D012583:Schwann Cells / Q000378:metabolism*; D012584:Sciatic Nerve / Q000378:metabolism*; D000097002:Gap Junction beta-1 Protein
chemical_list: D017630:Connexins; D012333:RNA, Messenger; D000097002:Gap Junction beta-1 Protein