Modulating the local immune environment via gene transfer to suppress intraocular inflammation
Lead Research Organisation:
University College London
Department Name: Institute of Ophthalmology
Abstract
Uveitis is a major cause of blindness in children and the working age population. It is a recurrent autoimmune disease that results in chronic inflammation in several parts of the eye. Autoimmune diseases occur when an individual‘s immune system mistakenly recognizes specific proteins within the body as foreign and mounts an attack against them, producing an inflammatory reaction that can cause irreversible damage. The mainstay of current treatment includes steroids and drugs that dampen the immune response, which may treat the inflammation, but often result in serious side effects.
We aim to develop viral gene therapy treatments which alter immune function in the eye and provide long-term, local suppression of inflammation without the need for systemic drugs and their associated side effects. Pre-developed gene carriers called ‘vectors‘ will be tested in a mouse model of uveitis. We will measure the effect on disease severity by examining ocular structure, the level of immune reaction within the eye and by testing visual function. This project will help us understand the predominant inflammatory pathways in uveitis and progress towards a full clinical trial in the near future. The work will additionally inform research into gene therapy for other autoimmune diseases.
We aim to develop viral gene therapy treatments which alter immune function in the eye and provide long-term, local suppression of inflammation without the need for systemic drugs and their associated side effects. Pre-developed gene carriers called ‘vectors‘ will be tested in a mouse model of uveitis. We will measure the effect on disease severity by examining ocular structure, the level of immune reaction within the eye and by testing visual function. This project will help us understand the predominant inflammatory pathways in uveitis and progress towards a full clinical trial in the near future. The work will additionally inform research into gene therapy for other autoimmune diseases.
Technical Summary
Uveitis is a recurrent autoimmune condition and a major cause of blindness in children and the working age population. If inadequately treated it can cause irreversible sight loss and current treatment options largely require systemic immunosuppression. Whilst improved treatments using systemic immunosuppressants and more recently biological therapies have been developed, there remain significant safety issues and side effects. Prolonged use of corticosteroids can induce cataract and glaucoma, as well as an increased risk of cardiovascular disease, bone loss and gastric ulceration. Multiple episodes of disease relapse also substantially increase the long-term cost of healthcare.
Viral gene therapy vectors encoding anti-inflammatory cytokines have been used to treat other autoimmune diseases such as rheumatoid arthritis. Results from this lab have shown that the technique can attenuate the mouse model of experimental autoimmune uveitis (EAU) and endotoxin-induced uveitis (EIU). Given our increased understanding of cytokine biology and receptor-ligand interactions involved in immune mediated damage in these models, it is now timely to investigate the translational potential of immunomodulatory gene therapy as an agent for regulating the local immune tissue environment.
AAV2/8 vectors efficiently transduce both photoreceptors and RPE cells, with high levels of transgene expression after just a few days. We will use AAV2/8 vectors carrying mouse cDNAs driven by CMV promoters to express different immunomodulatory molecules, including but not limited to, IL-1ra, IL-4, IL-10, CD200, TGF?, FasL and sTNFR (p55 [R1]and p75 [R2]) linked to eGFP by an IRES sequence, so that vector expression can be observed directly. These vectors have been generated in the lab, and most have been tested in vitro for biological function. Preliminary in vivo work showed a partial rescue of EAU and EIU. Further development of individual vectors and the use of combinations of vectors that target different pro-inflammatory pathways should provide a more complete, synergistic treatment of the disease and better preservation of visual function.
The AAV2/8 vector will be delivered by intravitreal, intracameral or subretinal injection and the therapeutic effect on established disease compared to untreated EAU controls. The prevention of disease onset will also be examined. Immunohistochemistry and multi-colour flow cytometry will be used to quantify and assess the phenotype of infiltrating cells within the retina. In vivo fundus imaging, including non-invasive Topical Endoscopic Fundal Imaging developed in this lab will determine the overall disease effect upon retinal morphology and vascular permeability. Electroretinography will be carried out to quantify the preservation of retinal function.
Viral gene therapy vectors encoding anti-inflammatory cytokines have been used to treat other autoimmune diseases such as rheumatoid arthritis. Results from this lab have shown that the technique can attenuate the mouse model of experimental autoimmune uveitis (EAU) and endotoxin-induced uveitis (EIU). Given our increased understanding of cytokine biology and receptor-ligand interactions involved in immune mediated damage in these models, it is now timely to investigate the translational potential of immunomodulatory gene therapy as an agent for regulating the local immune tissue environment.
AAV2/8 vectors efficiently transduce both photoreceptors and RPE cells, with high levels of transgene expression after just a few days. We will use AAV2/8 vectors carrying mouse cDNAs driven by CMV promoters to express different immunomodulatory molecules, including but not limited to, IL-1ra, IL-4, IL-10, CD200, TGF?, FasL and sTNFR (p55 [R1]and p75 [R2]) linked to eGFP by an IRES sequence, so that vector expression can be observed directly. These vectors have been generated in the lab, and most have been tested in vitro for biological function. Preliminary in vivo work showed a partial rescue of EAU and EIU. Further development of individual vectors and the use of combinations of vectors that target different pro-inflammatory pathways should provide a more complete, synergistic treatment of the disease and better preservation of visual function.
The AAV2/8 vector will be delivered by intravitreal, intracameral or subretinal injection and the therapeutic effect on established disease compared to untreated EAU controls. The prevention of disease onset will also be examined. Immunohistochemistry and multi-colour flow cytometry will be used to quantify and assess the phenotype of infiltrating cells within the retina. In vivo fundus imaging, including non-invasive Topical Endoscopic Fundal Imaging developed in this lab will determine the overall disease effect upon retinal morphology and vascular permeability. Electroretinography will be carried out to quantify the preservation of retinal function.
