QM107, a novel CD148 (RTP Type J) activating peptide therapy for treating neovascular age-related macular degeneration.

Background and purpose: Angiogenesis is a pathological component of neovascular age-related macular degeneration. Current therapies, although successful, are prone to high levels of patient non-response and a loss of efficacy over time, indicating the need to explore other therapeutic avenues. We have shown that an interaction between syndecan-2 and the tyrosine phosphatase receptor CD148 (RTP Type J) results in the ablation of angiogenesis. Here we exploit this pathway to develop a peptide activator of CD148 as a therapy for neovascular age-related macular degeneration.

Experimental approach: We tested a peptide (QM107) derived from syndecan-2 in a variety of angiogenesis models and a pre-clinical model of neovascular age-related macular degeneration. We assessed the toxicological and inflammatory profiles of QM107 and its stability in vitreous humour.

Key results: QM107 inhibits angiogenesis in ex vivo sprouting assays and disrupts endothelial microcapillary formation via inhibition of cell migration. QM107 acts through CD148, leading to changes in GSK3A phosphorylation and β1 integrin activation. QM107 elicits a negligible inflammatory response and exhibits limited toxicity in cultured cells, and is stable in vitreous humour. Finally, we show proof of concept that QM107 blocks angiogenesis in vivo using a model of neovascular age-related macular degeneration.

Conclusion and implications: We have developed a CD148 activating peptide which shows promise in inhibiting angiogenesis in models of neovascular age-related macular degeneration. This treatment could either represent an alternative or augment existing therapies, and owing to its distinct mode of action be used in patients who do not respond to existing treatments.