Retargeting adenovirus serotype 48 fiber knob domain by peptide incorporation

Coughlan, L., Uusi-Kerttula, H., Ma, J., Degg, B. P., Parker, A. L. and Baker, A. H. (2014) Retargeting adenovirus serotype 48 fiber knob domain by peptide incorporation. Human Gene Therapy, 25(4), pp. 385-394. (doi: 10.1089/hum.2014.016) (PMID:24617540)

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Adenovirus type 5 (Ad5) is a commonly used vector for gene therapy, but its efficacy is limited by high seroprevalence and off-target hepatic and splenic sequestration. In order to circumvent these limitations, the use of vectors derived from rare species adenoviruses is appealing. The opportunity to retarget rare species vectors to defined cell types through the incorporation of peptide ligands would be advantageous, particularly in targeting tumors and disseminated metastases. We used predictive structural modeling to assess the CD, DG, HI, and IJ loops of the Ad48 fiber knob and identify optimal incorporation locales for the 20-mer peptide, A20FMDV2 (A20). A20FMDV2 targets ανβ6 integrin, which is overexpressed in human carcinomas. Recombinant Ad48 fiber knob proteins Knob48, Knob48-CD-A20, Knob48-DG-A20, Knob48-HI-A20, and Knob48-IJ-A20 were engineered and purified after expression in Escherichia coli. We confirmed that Knob48, Knob48-CD-A20, and Knob48-IJ-A20 formed stable homotrimers. However, Knob48-DG-A20 and Knob-HI-A20 failed to form a trimer. All A20-modified knob proteins blocked the transduction of Ad5-EGFPA20 via ανβ6, demonstrating that the inserted A20 peptide was functional. In conclusion, we show that the CD and IJ loops of Ad48 represent suitable sites for targeting peptide incorporation. Interestingly, in vitro gene transfer mediated by the non-factor-X-binding Ad48 vector was not sensitive to immunoglobulins and complement when incubated in the presence of mouse serum, unlike Ad5. These data support the future generation of the corresponding Ad48 viral vectors, Ad48-CD-A20 and Ad48-IJ-A20, which may offer favorable characteristics for targeted delivery in vivo.

Item Type:Articles
Additional Information:This is a copy of an article published in the Human Gene Therapy © 2014 copyright Mary Ann Liebert, Inc.; Human Gene Therapy is available online at:
Glasgow Author(s) Enlighten ID:Baker, Professor Andrew and Ma, Dr Jiangtao and Parker, Dr Alan and Coughlan, Dr Lynda
Authors: Coughlan, L., Uusi-Kerttula, H., Ma, J., Degg, B. P., Parker, A. L., and Baker, A. H.
College/School:College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
Journal Name:Human Gene Therapy
Publisher:Mary Ann Liebert
ISSN (Online):1557-7422
Copyright Holders:Copyright © 2014 Mary Ann Liebert, Inc.
First Published:First published in Human Gene Therapy 25(4):385-394
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
486621Interrogation of the adenovirus hexon: A new paradigm for virus biology and application to therapeutic gene deliveryAndrew BakerBiotechnology and Biological Sciences Research Council (BBSRC)BB/G016844/1RI CARDIOVASCULAR & MEDICAL SCIENCES
581551Structural modification of the fiber knob domain of Human Adenovirus Type-48 (Ad48) to assess the suitability of targeting peptide incorporation within exposed loop regionsLynda CoughlanThe Nuffield Foundation (NUFFIELD)URB/39438RI CARDIOVASCULAR & MEDICAL SCIENCES