Lipid Nanoparticle Library Screen Reveals Lymphatic Endothelial Cell-Targeting Lipid Nanoparticle for Delivering Vascular Endothelial Growth Factor C mRNA after Lymphatic Injury

Dysfunction of the lymphatic system following injury, disease, or cancer treatment can lead to lymphedema, a debilitating condition with no cure. Advances in targeted therapy have shown promise for treating diseases where conventional therapies, including broad-spectrum chemotherapy, surgical interventions, and palliative care, have often failed to achieve durable responses. As lymphatic vessels have recently emerged as a therapeutic target, nucleic acid delivery via nanoparticles to lymphatic endothelial cells (LECs) has been studied utilizing lymphatic drainage; however, there are no approaches to modulate the chemical compositions of lipid nanoparticles (LNPs) to optimize LEC specificity. To identify an LNP that effectively delivers mRNA to LECs after intradermal (ID) injection, we screened a library of 150 LNPs in total spread out over 3 screening rounds. The 150 formulations had a variety of chemical compositions and were assessed for both self-assembly and delivery <i>in vivo</i> to LECs. We identified and validated several LNP formulations optimized for high LEC uptake when administered ID and compared their efficacy for delivery of functional mRNA with that of free mRNA and mRNA delivered with a commercially available MC3-based LNP (Onpattro). The lead LEC-LNP was then loaded with VEGFC mRNA to test the therapeutic advantage of this LEC enrichment (namely, LNP7) for treating a mouse tail lymphatic injury model. A single dose of VEGFC mRNA delivered via LNP7 resulted in enhanced LEC proliferation at the site of injury and an increase in lymphatic function up to 14 days postsurgery. Our results suggest a therapeutic potential of VEGFC mRNA using lymphatic-enriched LNP delivery for alleviating lymphatic dysfunction observed during lymphatic injury and could provide a promising approach for targeted and transient lymphangiogenic therapy.