title: Lentiviral vectors that express UGT1A1 in liver and contain miR-142 target sequences normalize hyperbilirubinemia in Gunn rats.
abstract: OBJECTIVE
  Crigler-Najjar type 1 (CN-I) is an inherited liver disease caused by an absence of bilirubin-uridine 5'-diphosphate-glucuronosyltransferase (UGT1A1) activity. It results in life-threatening levels of unconjugated bilirubin, and therapeutic options are limited. We used adult Gunn rats (an animal model of the disease) to evaluate the efficiency of lentiviral-based gene therapy to express UGT1A1 in liver.
  
  
  METHODS
  Gunn rats were given intraportal injections of VSVG-pseudotyped lentiviral vectors that encode UGT1A1 under the control of a liver-specific transthyretin promoter (mTTR.hUGT1A1); this vector does not contain target sequences for miR-142, a microRNA that is expressed specifically in hematopoietic cells. Rats were also injected with the vector mTTR.hUGT1A1.142T, which contains 4 copies of the miR-142 target sequences; its messenger RNA should be degraded in antigen-presenting cells. Bilirubinemia was monitored, and the presence of transduced hepatocytes was analyzed by quantitative polymerase chain reaction. Vector expression was tested in vitro in rat hematopoietic cells.
  
  
  RESULTS
  In Gunn rats, bilirubin levels normalized 2 weeks after administration of mTTR.hUGT1A1. However, hyperbilirubinemia resumed 8 weeks after vector administration, concomitant with the induction of an immune response. In contrast, in rats injected with mTTR-UGT1A1.142T, bilirubin levels normalized for up to 6 months and transduced cells were not eliminated.
  
  
  CONCLUSIONS
  Lentiviral vectors that express UGT1A1 reduce hyperbilirubinemia in immunocompetent Gunn rats for at least 6 months. The immune response against virally expressed UGT1A1 can be circumvented by inclusion of miR-142 target sequences, which reduce vector expression in antigen-presenting cells. This lentiviral-based gene therapy approach might be developed to treat patients with CN-I.
authors.affiliation: INSERM Unité 948, CHU Hôtel Dieu, Nantes, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Schmitt
authors.forename: Séverine
authors.initials: S
authors.lastname: Remy
authors.forename: Anne
authors.initials: A
authors.lastname: Dariel
authors.forename: Maude
authors.initials: M
authors.lastname: Flageul
authors.forename: Virginie
authors.initials: V
authors.lastname: Pichard
authors.forename: Sébastien
authors.initials: S
authors.lastname: Boni
authors.forename: Claire
authors.initials: C
authors.lastname: Usal
authors.forename: Anne
authors.initials: A
authors.lastname: Myara
authors.forename: Sophie
authors.initials: S
authors.lastname: Laplanche
authors.forename: Ignacio
authors.initials: I
authors.lastname: Anegon
authors.forename: Philippe
authors.initials: P
authors.lastname: Labrune
authors.forename: Guillaume
authors.initials: G
authors.lastname: Podevin
authors.forename: Nicolas
authors.initials: N
authors.lastname: Ferry
authors.forename: Tuan Huy
authors.initials: TH
authors.lastname: Nguyen
mesh_terms: D000818:Animals; D000906:Antibodies / Q000097:blood; D000938:Antigen-Presenting Cells / Q000276:immunology; D001663:Bilirubin / Q000097:blood; D015415:Biomarkers / Q000097:blood; D003414:Crigler-Najjar Syndrome / Q000201:enzymology / Q000235:genetics / Q000276:immunology / Q000628:therapy*; D004195:Disease Models, Animal; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D014453:Glucuronosyltransferase / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D006367:HeLa Cells; D006801:Humans; D016086:Lentivirus / Q000235:genetics*; D008099:Liver / Q000201:enzymology*; D008297:Male; D035683:MicroRNAs / Q000378:metabolism*; D011228:Prealbumin / Q000235:genetics; D011401:Promoter Regions, Genetic; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011911:Rats, Gunn; D013997:Time Factors; D014161:Transduction, Genetic; D000099148:UGT1A1 Enzyme
chemical_list: D000906:Antibodies; D001663:Bilirubin; D015415:Biomarkers; D014453:Glucuronosyltransferase; D035683:MicroRNAs; D011228:Prealbumin; D012333:RNA, Messenger; D000099148:UGT1A1 Enzyme