Hepatocyte Heparan Sulfate Is Required for Adeno-Associated Virus 2 but Dispensable for Adenovirus 5 Liver Transduction In Vivo

• Type of Material: Article
• Authors: Anne K. Zaiss, University of California Los Angeles; Erin M. Foley, University of California San Diego; Roger Lawrence, University of California San Diego; Lina S. Schneider, University of California Los Angeles; Hamidreza Hoveida, University of California Los Angeles; Patrick Secrest, University of California San Diego; Arthur B. Catapang, University of California Los Angeles; Yu Yamaguchi, Sanford-Burnham Medical Research Institute; Ramon Alemany, IDIBELL-Institut Catala d'Oncologia; Dmitry Shayakhmetov, Emory University; Jeffrey D. Esko, University of California San Diego; Harvey R. Herschman, University of California Los Angeles
• Language: English
• Date: 2016-01-01
• Publisher: American Society for Microbiology
• Publication Version: Final Published Version
• Copyright Statement: © 2015, American Society for Microbiology. All Rights Reserved.
• Final Published Version (URL): http://dx.doi.org/10.1128/JVI.01939-15
• Title of Journal or Parent Work: Journal of Virology
• ISSN: 0022-538X
• Volume: 90
• Issue: 1
• Start Page: 412
• End Page: 420
• Grant/Funding Information: This work was supported by NIH grants P50 CA086306-08 (H.R.H.) and GM33063 and HL107150 (J.D.E.).; A.K.Z. is the recipient of an American Society of Hematology (ASH) Scholar Award.
• Keywords: INFECTION; FACTOR-X; GENE-TRANSFER; Virology; Science & Technology; THERAPY; Life Sciences & Biomedicine; PROTEOGLYCAN BINDING; RECEPTOR; EXPRESSION; HEXON; AMINO-ACIDS; IDENTIFICATION
• Research Categories: Biology, Molecular; Health Sciences, General; Biology, Virology

Abstract

Adeno-associated virus 2 (AAV2) and adenovirus 5 (Ad5) are promising gene therapy vectors. Both display liver tropism and are currently thought to enter hepatocytes in vivo through cell surface heparan sulfate proteoglycans (HSPGs). To test directly this hypothesis, we created mice that lack Ext1, an enzyme required for heparan sulfate biosynthesis, in hepatocytes. Ext1HEP mutant mice exhibit an 8-fold reduction of heparan sulfate in primary hepatocytes and a 5-fold reduction of heparan sulfate in whole liver tissue. Conditional hepatocyte Ext1 gene deletion greatly reduced AAV2 liver transduction following intravenous injection. Ad5 transduction requires blood coagulation factor X (FX); FX binds to the Ad5 capsid hexon protein and bridges the virus to HSPGs on the cell surface. Ad5.FX transduction was abrogated in primary hepatocytes from Ext1HEP mice. However, in contrast to the case with AAV2, Ad5 transduction was not significantly reduced in the livers of Ext1HEP mice. FX remained essential for Ad5 transduction in vivo in Ext1HEP mice. We conclude that while AAV2 requires HSPGs for entry into mouse hepatocytes, HSPGs are dispensable for Ad5 hepatocyte transduction in vivo. This study reopens the question of how adenovirus enters cells in vivo.