Screening for lipid nanoparticles that modulate the immune activity of helper T cells towards enhanced antitumour activity.

Lipid nanoparticles (LNPs) can be designed to potentiate cancer immunotherapy by promoting their uptake by antigen-presenting cells, stimulating the maturation of these cells and modulating the activity of adjuvants. Here we report an LNP-screening method for the optimization of the type of helper lipid and of lipid-component ratios to enhance the delivery of tumour-antigen-encoding mRNA to dendritic cells and their immune-activation profile towards enhanced antitumour activity. The method involves screening for LNPs that enhance the maturation of bone-marrow-derived dendritic cells and antigen presentation in vitro, followed by assessing immune activation and tumour-growth suppression in a mouse model of melanoma after subcutaneous or intramuscular delivery of the LNPs. We found that the most potent antitumour activity, especially when combined with immune checkpoint inhibitors, resulted from a coordinated attack by T cells and NK cells, triggered by LNPs that elicited strong immune activity in both type-1 and type-2 T helper cells. Our findings highlight the importance of optimizing the LNP composition of mRNA-based cancer vaccines to tailor antigen-specific immune-activation profiles.

Multi-step screening of DNA/lipid nanoparticles and co-delivery with siRNA to enhance and prolong gene expression.

Lipid nanoparticles hold great potential as an effective non-viral vector for nucleic acid-based gene therapy. Plasmid DNA delivery can result in extended transgene expression compared to mRNA-based technologies, yet there is a lack of systematic investigation into lipid nanoparticle compositions for plasmid DNA delivery. Here, we report a multi-step screening platform to identify optimized plasmid DNA lipid nanoparticles for liver-targeted transgene expression. To achieve this, we analyze the role of different helper lipids and component ratios in plasmid DNA lipid nanoparticle-mediated gene delivery in vitro and in vivo. Compared to mRNA LNPs and in vivo-jetPEI/DNA nanoparticles, the identified plasmid DNA lipid nanoparticles successfully deliver transgenes and mediate prolonged expression in the liver following intravenous administration in mice. By addressing different physiological barriers in a stepwise manner, this screening platform can efficiently down select effective lipid nanoparticle candidates from a lipid nanoparticle library of over 1000 formulations. In addition, we substantially extend the duration of plasmid DNA nanoparticle-mediated transgene expression using a DNA/siRNA co-delivery approach that targets transcription factors regulating inflammatory response pathways. This lipid nanoparticle-based co-delivery strategy further highlights the unique advantages of an extended transgene expression profile using plasmid DNA delivery and offers new opportunities for DNA-based gene medicine applications.