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Science & Technology

Characterization of Endosomal Escape of siRNA for Improved Nucleic Acid-Based Therapeutics

By 23rd May 2020No Comments

The following study was conducted by Scientists from Faculty of Medicine, Lund University, Lund, Sweden; Wallenberg Center for Molecular Medicine, Lund, Sweden; Skane University Hospital, Lund, Sweden. Study is published in Nature Communications Journal as detailed below.

Nature Communications; Volume 11, Article Number: 1809; (2020)

Imaging Small Molecule-Induced Endosomal Escape of siRNA


Small interfering RNAs (siRNAs) are a new class of promising therapeutic molecules that can be used for sequence-specific downregulation of disease-causing genes. However, endosomal entrapment of siRNA is a key hurdle for most delivery strategies, limiting the therapeutic effect. Here, we use live-cell microscopy and cytosolic galectin-9 as a sensor of membrane damage, to probe fundamental properties of endosomal escape of cholesterol-conjugated siRNA induced by endosome-disrupting compounds. We demonstrate efficient release of ligand-conjugated siRNA from vesicles damaged by small molecules, enhancing target knockdown up to ∼47-fold in tumor cells. Still, mismatch between siRNA-containing and drug-targeted endolysosomal compartments limits siRNA activity improvement. We also show widespread endosomal damage in macroscopic tumor spheroids after small molecule treatment, substantially improving siRNA delivery and knockdown throughout the spheroid. We believe the strategy to characterize endosomal escape presented here will be widely applicable, facilitating efforts to improve delivery of siRNA and other nucleic acid-based therapeutics.


Nature Communications



Du Rietz, H., H. Hedlund, et al. (2020). “Imaging small molecule-induced endosomal escape of siRNA.” Nature Communications 11(1): 1809.