Delivering topical IL-33 with a cell penetrating peptide to treat neovascular age-related macular degeneration.

Abstract

Purpose : Age-related macular degeneration (AMD) is the most common cause of central vision loss globally. Neovascular AMD (nAMD) is currently treated with regular intraocular injections of anti-VEGF therapies, to which some patients are unresponsive, while multiple injections are not well-tolerated and can cause complications including infection. We previously demonstrated intraocular delivery of recombinant interleukin-33 (IL-33) reduced laser-induced choroidal neovascularisation (CNV) pathology in a mouse model, offering a promising new treatment. Additionally, an eyedrop of bevacizumab complexed to a cell penetrating peptide (CPP) reduced lesion size equivalent to intravitreal injection delivery in a mouse CNV model. Thus, we propose combining IL-33 immunotherapy and our delivery agent, IL-33+CPP6, to be developed as a topical formulation.

Methods : Human recombinant IL-33 was complexed with the CPP to assess cell toxicity, MTT and LDH assays for 48h over a dose range of 0.2–200pg/ul in cultured human RPE (ARPE-19) and human ocular choroidal fibroblasts (HOCFs). HOCF scratch assay was performed and cells treated with media, vehicle, CPP, IL-33 (200pg/ul) or IL-33+CPP and imaged over 48h. The percentage wound closure (end vs start width) was measured using Cell IQ software. N=3, repeated on 3 independent occasions.

Results : IL-33+CPP complexes were non-toxic to ARPE-19 or HOCFs across a dose range (0.2–200pg/ul). In ARPE-19 cells and HOCFs, there were no differences after treatment in total viable cell number (total cell LDH; P=0.8306, P=0.9641, ANOVA) or significant changes in cellular viability (MTT assay; P=0.9772, P=0.2910, ANOVA). Importantly IL-33+CPP had equivalent significant biological effects to IL-33 alone, reducing wound healing (~15% less wound closure at 48h vs media/vehicle/CPP6). Across groups in scratch assay, there was a significant effect on percentage wound closure (P=0.0430, ANOVA), with borderline significance in post-hoc analysis (Tukey) between media and IL-33 (P=0.0529) and IL-33+CPP (P=0.0639) treatments.

Conclusions : IL-33+CPP is a promising treatment in a formulation of a drop for nAMD. IL-33+CPP demonstrates non-toxicity and has preserved biological effect as direct IL-33 administration. Further experiments will assess ocular penetration and in vivo efficacy of our topical administration.

This is a 2021 ARVO Annual Meeting abstract.