Inclusion of the Woodchuck Hepatitis Virus Posttranscriptional Regulatory Element Enhances AAV2-Driven Transduction of Mouse and Human Retina.
The woodchuck hepatitis virus posttranscriptional regulatory element (WPRE) has been included in the transgene cassette of adeno-associated virus (AAV) in several gene therapy clinical trials, including those for inherited retinal diseases. However, the extent to which WPRE increases transgene expression in the retina is still unclear. To address this question, AAV2 vectors containing a reporter gene with and without WPRE were initially compared in vitro and subsequently in vivo by subretinal delivery in mice. In both instances, the presence of WPRE led to significantly higher levels of transgene expression as measured by fundus fluorescence, western blot, and immunohistochemistry. The two vectors were further compared in human retinal explants derived from patients undergoing clinically indicated retinectomy, where again the presence of WPRE resulted in an enhancement of reporter gene expression. Finally, an analogous approach using a transgene currently employed in a clinical trial for choroideremia delivered similar results both in vitro and in vivo, confirming that the WPRE effect is transgene independent. Our data fully support the inclusion of WPRE in ongoing and future AAV retinal gene therapy trials, where it may allow a therapeutic effect to be achieved at an overall lower dose of vector.
Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK.
Maria I
MI
Patrício
Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK.
Alun R
AR
Barnard
Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; Moorfields Eye Hospital, NHS Foundation Trust, London EC1V 2PD, UK.
Harry O
HO
Orlans
Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK.
Michelle E
ME
McClements
Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; Moorfields Eye Hospital, NHS Foundation Trust, London EC1V 2PD, UK. Electronic address: enquiries@eye.ox.ac.uk.
Robert E
RE
MacLaren
AAV2; WPRE; choroideremia; gene therapy; human retina; mouse retina