Abstract

Previous studies have demonstrated that intravitreal delivery of brain-derived neurotrophic factor (BDNF) by injection of recombinant protein or by gene therapy can alleviate retinal ganglion cell (RGC) loss after optic nerve injury. BDNF gene therapy can improve RGC survival in experimental models of glaucoma, the leading cause of irreversible blindness worldwide. However, the therapeutic efficacy of BDNF supplementation alone is time limited at least in part due to BDNF receptor downregulation. Tropomyosin-related receptor kinase-B (TrkB) downregulation has been reported in many neurological diseases including glaucoma, potentially limiting the effect of sustained or repeated BDNF delivery.

Here, we characterize a novel adeno-associated virus (AAV) gene therapy (AAV2 TrkB-2A-mBDNF) that not only increases BDNF production but also improves long-term neuroprotective signaling by increasing expression of the BDNF receptor (TrkB) within the inner retina. This approach leads to significant and sustained elevation of survival signaling pathways ERK and AKT within RGCs over 6 months and avoids the receptor downregulation which we observe with treatment with AAV2 BDNF alone. We validate the neuroprotective efficacy of AAV2 TrkB-2A-mBDNF in a mouse model of optic nerve injury, where it outperforms conventional AAV2 BDNF or AAV2 TrkB therapy, before showing powerful proof of concept neuroprotection of RGCs and axons in a rat model of chronic intraocular pressure (IOP) elevation. We also show that there are no adverse effects of the vector on retinal structure or function as assessed by histology and electroretinography in young or aged animals. Further studies are underway to explore the potential of this vector as a candidate for progression into clinical studies to protect RGCs in patients with glaucoma and progressive visual loss despite conventional IOP-lowering treatment.

Details

Title
Neuroprotection of retinal ganglion cells by a novel gene therapy construct that achieves sustained enhancement of brain-derived neurotrophic factor/tropomyosin-related kinase receptor-B signaling
Author
Osborne, Andrew 1 ; Khatib, Tasneem Z 2 ; Songra, Lalana 3 ; Barber, Amanda C 3 ; Hall, Katie 3 ; Kong, George Y X 4 ; Widdowson, Peter S 5 ; Martin, Keith R 6 

 John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Quethera Ltd, Cambridge, UK 
 John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Eye Department, Addenbrooke’s Hospital, Cambridge, UK 
 John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK 
 Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; University of Melbourne, Melbourne, Australia 
 Quethera Ltd, Cambridge, UK 
 John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Quethera Ltd, Cambridge, UK; Eye Department, Addenbrooke’s Hospital, Cambridge, UK; Cambridge NIHR Biomedical Research Centre, Cambridge, UK; Wellcome Trust—MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK 
Pages
1-18
Publication year
2018
Publication date
Sep 2018
Publisher
Springer Nature B.V.
e-ISSN
20414889
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2112602095
Copyright
© 2018. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.