title: Hepatitis B virus infection enhances susceptibility toward adeno-associated viral vector transduction in vitro and in vivo.
abstract: Gene therapy has become an accepted concept for the treatment of a variety of different diseases. In contrast to preclinical models, subjects enrolled in clinical trials, including gene therapy, possess a history of infection with microbes that may influence its safety and efficacy. Especially, viruses that establish chronic infections in the liver, one of the main targets for in vivo gene therapy, raise important concerns. Among them is the hepatitis B virus (HBV), which has chronically infected more than 350 million people worldwide. Here, we investigated the effect of HBV on adeno-associated viral (AAV) vectors, the most frequently applied gene transfer vehicles for in vivo gene therapy. Unexpectedly, we found that HBV greatly improved AAV transduction in cells replicating HBV and identified HBV protein x (HBx) as a key factor. Whereas HBV-positive and -negative cells were indistinguishable with respect to cell-entry efficiency, significantly higher numbers of AAV vector genomes were successfully delivered to the nucleus in the presence of HBV. The HBV-promoting effect was abolished by inhibitors of phosphatidylinositol 3-kinase (PI3K). PI3K was required for efficient trafficking of AAV to the nucleus and was enhanced in HBV-replicating cells and upon HBx expression. Enhancement of AAV transduction was confirmed in vivo using HBV transgenic mice and could successfully be applied to inhibit HBV progeny release.
  
  
  CONCLUSIONS
  Our results demonstrate that acute, as well as chronic, infections with unrelated viruses change the intracellular milieu, thereby likely influencing gene therapy outcomes. In the case of HBV, HBx-mediated enhancement of AAV transduction is an advantage that could be exploited for development of novel treatments of HBV infection.
authors.affiliation: Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; German Center for Infection Research, Partner sites Bonn-Cologne and Munich, Germany; Department I of Internal Medicine, University Hospital Cologne, Cologne, Germany.
authors.forename: Marianna
authors.initials: M
authors.lastname: Hösel
authors.forename: Julie
authors.initials: J
authors.lastname: Lucifora
authors.forename: Thomas
authors.initials: T
authors.lastname: Michler
authors.forename: Gisela
authors.initials: G
authors.lastname: Holz
authors.forename: Marion
authors.initials: M
authors.lastname: Gruffaz
authors.forename: Stephanie
authors.initials: S
authors.lastname: Stahnke
authors.forename: Fabien
authors.initials: F
authors.lastname: Zoulim
authors.forename: David
authors.initials: D
authors.lastname: Durantel
authors.forename: Mathias
authors.initials: M
authors.lastname: Heikenwalder
authors.forename: Dirk
authors.initials: D
authors.lastname: Nierhoff
authors.forename: Rachel
authors.initials: R
authors.lastname: Millet
authors.forename: Anna
authors.initials: A
authors.lastname: Salvetti
authors.forename: Ulrike
authors.initials: U
authors.lastname: Protzer
authors.forename: Hildegard
authors.initials: H
authors.lastname: Büning
mesh_terms: D000818:Animals; D000229:Dependovirus / Q000235:genetics*; D004789:Enzyme Activation / Q000235:genetics; D005260:Female; D020022:Genetic Predisposition to Disease; D005822:Genetic Vectors; D057809:HEK293 Cells; D006509:Hepatitis B / Q000235:genetics / Q000628:therapy / Q000821:virology*; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D007371:Interferon-gamma / Q000235:genetics; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D034741:RNA, Small Interfering / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics; D014161:Transduction, Genetic; D054334:Viral Regulatory and Accessory Proteins; D014779:Virus Replication / Q000235:genetics
chemical_list: D034741:RNA, Small Interfering; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; D007371:Interferon-gamma