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A drug-tunable Flt23k gene therapy for controlled intervention in retinal neovascularization


Chen, J and Lin, F-L and Leung, JYK and Tu, L and Wang, J-H and Chuang, Y-F and Li, F and Shen, H-H and Dusting, GJ and Wong, VHY and Lisowski, L and Hewitt, AW and Bui, BV and Zhong, J and Liu, G-S, A drug-tunable Flt23k gene therapy for controlled intervention in retinal neovascularization, Angiogenesis, 24, (1) pp. 97-110. ISSN 0969-6970 (2020) [Refereed Article]

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Copyright 2020 Springer Nature B.V.

DOI: doi:10.1007/s10456-020-09745-7


Gene therapies that chronically suppress vascular endothelial growth factor (VEGF) represent a new approach for managing retinal vascular leakage and neovascularization. However, constitutive suppression of VEGF in the eye may have deleterious side effects. Here, we developed a novel strategy to introduce Flt23k, a decoy receptor that binds intracellular VEGF, fused to the destabilizing domain (DD) of Escherichia coli dihydrofolate reductase (DHFR) into the retina. The expressed DHFR(DD)-Flt23k fusion protein is degraded unless "switched on" by administering a stabilizer; in this case, the antibiotic trimethoprim (TMP). Cells transfected with the DHFR(DD)-Flt23k construct expressed the fusion protein at levels correlated with the TMP dose. Stabilization of the DHFR(DD)-Flt23k fusion protein by TMP was able to inhibit intracellular VEGF in hypoxic cells. Intravitreal injection of self-complementary adeno-associated viral vector (scAAV)-DHFR(DD)-Flt23k and subsequent administration of TMP resulted in tunable suppression of ischemia-induced retinal neovascularization in a rat model of oxygen-induced retinopathy (OIR). Hence, our study suggests a promising novel approach for the treatment of retinal neovascularization. Schematic diagram of the tunable system utilizing the DHFR(DD)-Flt23k approach to reduce VEGF secretion. a The schematic shows normal VEGF secretion. b Without the ligand TMP, the DHFR(DD)-Flt23k protein is destabilized and degraded by the proteasome. c In the presence of the ligand TMP, DHFR(DD)-Flt23k is stabilized and sequestered in the ER, thereby conditionally inhibiting VEGF. Green lines indicate the intracellular and extracellular distributions of VEGF. Blue lines indicate proteasomal degradation of the DHFR(DD)-Flt23k protein. Orange lines indicate the uptake of cell-permeable TMP. TMP, trimethoprim; VEGF, vascular endothelial growth factor; ER, endoplasmic reticulum.

Item Details

Item Type:Refereed Article
Keywords:gene therapy, diabetic retinopathy, angiogenesis, VEGF, AAV, destabilizing domain, Flt23k, retinal neovascularization, trimethoprim
Research Division:Biomedical and Clinical Sciences
Research Group:Medical biotechnology
Research Field:Gene and molecular therapy
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Chen, J (Ms Jane Chen)
UTAS Author:Lin, F-L (Dr Fan-Li Lin)
UTAS Author:Leung, JYK (Dr Jacqueline Leung)
UTAS Author:Chuang, Y-F (Dr Yu-Fan Chuang)
UTAS Author:Li, F (Dr Fan Li)
UTAS Author:Hewitt, AW (Professor Alex Hewitt)
UTAS Author:Liu, G-S (Associate Professor Guei-Sheung Liu)
ID Code:140994
Year Published:2020
Funding Support:National Health and Medical Research Council (1185600)
Web of Science® Times Cited:13
Deposited By:Menzies Institute for Medical Research
Deposited On:2020-09-17
Last Modified:2022-08-26
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