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Updated: Jun 30, 2026
Limbal Approach-Subretinal Injection of Viral Vectors for Gene Therapy in Mice Retinal Pigment Epithelium
Published on: August 7, 2015
Nanobody-based gene therapy targeting complement component C3 reduces choroidal neovascularization in mice
Emilie Grarup Jensen1, Thomas Stax Jakobsen1,2, Gloriane Schnabolk3
1Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark.
Abstract:
Wet age-related macular degeneration (wAMD) is a leading cause of vision loss and is characterized by choroidal neovascularization (CNV). Current CNV management requires multiple treatments and lacks long-term efficiency, creating a need for better therapeutics. wAMD pathogenesis is associated with excessive activation of the complement system, contributing to retinal damage. Therefore, we generated a vector expressing the small alternative pathway-targeting nanobody, hC3Nb1, to treat wAMD. We demonstrate that hC3Nb1 is efficiently expressed and secreted by mammalian cells and shows full alternative pathway and partial classical pathway inhibition in vitro. A dual-promoter approach was used to generate a lentiviral-based vector for co-expression of hC3Nb1 and marker protein eGFP. Profound and safe hC3Nb1-expression, along with its secretion from the retinal pigment epithelium (RPE), was confirmed following subretinal injection of nanobody expressing-vector in mice. The therapeutic potential of vector-encoded hC3Nb1 was demonstrated in vitro by protecting RPE from complement-mediated stress, and in vivo by reducing laser-induced CNV sizes in a mouse model consistent with complement inhibition. For the first time, nanobodies expressed in the eye are used therapeutically, and our findings suggest that hC3Nb1-based gene therapy may be a safe and long-acting treatment for wAMD and other chorioretinal diseases with dysregulated complement activation.
Insights
Gene therapy using nanobodies offers a promising new treatment for wet age-related macular degeneration (wAMD). This approach targets the complement system, reducing choroidal neovascularization (CNV) and protecting vision.
Area of Science:
- Ophthalmology
- Immunology
- Gene Therapy
Background:
- Wet age-related macular degeneration (wAMD) is a primary cause of vision impairment, characterized by choroidal neovascularization (CNV).
- Current treatments for CNV are insufficient, necessitating novel therapeutic strategies.
- The complement system's overactivation plays a key role in wAMD pathogenesis and retinal damage.
Purpose of the Study:
- To develop and evaluate a gene therapy approach using a nanobody targeting the alternative complement pathway for wAMD treatment.
- To assess the safety and efficacy of expressing the nanobody hC3Nb1 within the eye.
Main Methods:
- Generation of a lentiviral vector for co-expression of hC3Nb1 and eGFP.
- In vitro assessment of hC3Nb1's complement inhibition activity.
- Subretinal injection of the vector in mice to confirm expression, secretion, and safety.
- In vitro and in vivo evaluation of therapeutic effects on retinal pigment epithelium (RPE) and laser-induced CNV.
Main Results:
- The hC3Nb1 nanobody was efficiently expressed and secreted by mammalian cells, inhibiting both alternative and classical complement pathways in vitro.
- Subretinal delivery of the vector resulted in safe and sustained hC3Nb1 expression and secretion from RPE cells in mice.
- Vector-encoded hC3Nb1 protected RPE cells from complement-mediated damage in vitro and reduced CNV size in vivo.
Conclusions:
- Nanobody-based gene therapy represents a novel therapeutic strategy for wAMD.
- This approach demonstrates potential for safe, long-acting treatment of wAMD and other complement-mediated chorioretinal diseases.
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