title: α- L-iduronidase gene-based therapy using the phiC31 system to treat mucopolysaccharidose type I mice.
abstract: BACKGROUND
  Mucopolysaccharidose type I (MPSI) is a lysosomal monogenic disease caused by mutations in the gene for α- L-iduronidase (IDUA). MPSI patients need a constant supply of IDUA to alleviate progression of the disease. IDUA gene transfer using integrative vectors might provide a definitive solution and support advancement to clinical trials, although studies have not yet been satisfactory. To achieve a stable IDUA gene expression in vivo, phiC31 was tested in the present study.
  
  
  METHODS
  Several plasmid vectors were constructed and IDUA-/- mice were treated with cyclophosphamide and transfected with these vectors hydrodynamically via tail veins. IDUA expression was monitored over time. Treated and nontreated mice underwent an open-field test at age 8 months, and IDUA activity and glycosaminoglycan (GAG) content of tissues were evaluated.
  
  
  RESULTS
  High levels of IDUA activity were detected initially (>1000 U/ml), although these levels decayed over time. The reinjection of vectors produced a similar profile of IDUA decay. Three out of six treated mice had IDUA activity in the livers, and also showed lower GAG content, reduced lysosomes and better locomotion. To investigate unsustained IDUA production, wild-type mice were submitted to the same gene therapy procedure, which generated a similar profile of IDUA decay. Anti-IDUA antibody was detected in the sera of these animals. In addition, we also found three methylated sites in the cytomegalovirus promoter region.
  
  
  CONCLUSIONS
  phiC31-mediated gene therapy resulted in an important improvement in IDUA-/- mice, including locomotion, although the obstacles that need to be overcome to enable long-term gene therapy for MPSI are also noted.
authors.affiliation: Department of Biophysics, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Roberta Sessa
authors.initials: RS
authors.lastname: Stilhano
authors.forename: Priscila Keiko Matsumoto
authors.initials: PK
authors.lastname: Martin
authors.forename: Suely Maymone
authors.initials: SM
authors.lastname: de Melo
authors.forename: Vivian Yochiko
authors.initials: VY
authors.lastname: Samoto
authors.forename: Giovani Bravin
authors.initials: GB
authors.lastname: Peres
authors.forename: Yara Maria Correa
authors.initials: YM
authors.lastname: da Silva Michelacci
authors.forename: Flavia Helena
authors.initials: FH
authors.lastname: da Silva
authors.forename: Vanessa Gonçalves
authors.initials: VG
authors.lastname: Pereira
authors.forename: Vania
authors.initials: V
authors.lastname: D'Almeida
authors.forename: Adriana Taveira
authors.initials: AT
authors.lastname: da Cruz
authors.forename: Miriam Galvonas
authors.initials: MG
authors.lastname: Jasiulionis
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Han
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D002460:Cell Line; D019175:DNA Methylation; D004195:Disease Models, Animal; D004789:Enzyme Activation; D005260:Female; D015870:Gene Expression; D023061:Gene Order; D018014:Gene Transfer Techniques; D017930:Genes, Reporter; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000008:administration & dosage / Q000235:genetics*; D057809:HEK293 Cells; D059765:Homologous Recombination; D006801:Humans; D007068:Iduronidase / Q000235:genetics* / Q000378:metabolism; D008099:Liver / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009043:Motor Activity; D008059:Mucopolysaccharidosis I / Q000235:genetics* / Q000378:metabolism / Q000628:therapy; D059372:Nucleotide Motifs; D011401:Promoter Regions, Genetic; D014162:Transfection
chemical_list: D007068:Iduronidase
keywords: IDUA; gene therapy; mucopolysaccharidose type I; phiC31 integrase