Efficient Biodistribution and Gene Silencing in the Lung epithelium via Intravenous Liposomal Delivery of siRNA

RNA interference (RNAi) may provide a therapeutic solution to many pulmonary epithelium diseases. However, the main barrier to the clinical use of RNAi remains the lack of efficient delivery vectors. Research has mainly concentrated on the intranasal route of delivery of short interfering RNA (siRNA) effector molecules for the treatment of respiratory diseases. However, this may be complicated in a diseased state due to the increased fluid production and tissue remodeling. Therefore, we investigated our hydration of a freeze-dried matrix (HFDM) formulated liposomes for systemic delivery to the lung epithelium. Here, we show that 45 ± 2% of epithelial murine lung cells receive siRNA delivery upon intravenous (IV) liposomal administration. Furthermore, we demonstrate that liposomal siRNA delivery resulted in targeted gene and protein knockdown throughout the lung, including lung epithelium. Taken together, this is the first description of lung epithelial delivery via cationic liposomes, and provides a proof of concept for the use of IV liposomal RNAi delivery to specifically knockdown targeted genes in the respiratory system. This approach may provide an attractive alternate therapeutic delivery strategy for the treatment of lung epithelium diseases.