Surfactant protein B promotes cytosolic SiRNA delivery by adopting a virus-like mechanism of action
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
RNA therapeutics are poised to revolutionize medicine. To unlock the full potential of RNA drugs, safe and efficient (nano)formulations to deliver them inside target cells are required. Endosomal sequestration of nanocarriers represents a major bottleneck in nucleic acid delivery. Gaining more detailed information on the intracellular behavior of RNA nanocarriers is crucial to rationally develop delivery systems with improved therapeutic efficiency. Surfactant protein B (SP-B) is a key component of pulmonary surfactant (PS), essential for mammalian breathing. In contrast to the general belief that PS should be regarded as a barrier for inhaled nanomedicines, we recently discovered the ability of SP-B to promote gene silencing by siRNA-loaded and lipid-coated nanogels. However, the mechanisms governing this process are poorly understood. The major objective of this work was to obtain mechanistic insights into the SP-B-mediated cellular delivery of siRNA. To this end, we combined siRNA knockdown experiments, confocal microscopy, and focused ion beam scanning electron microscopy imaging in an in vitro non-small-cell lung carcinoma model with lipid mixing assays on vesicles that mimic the composition of (intra)cellular membranes. Our work highlights a strong correlation between SP-B-mediated fusion with anionic endosomal membranes and cytosolic siRNA delivery, a mode of action resembling that of certain viruses and virus-derived cell-penetrating peptides. Building on these gained insights, we optimized the SP-B proteolipid composition, which dramatically improved delivery efficiency. Altogether, our work provides a mechanistic understanding of SP-B-induced perturbation of intracellular membranes, offering opportunities to fuel the rational design of SP-B-inspired RNA nanoformulations for inhalation therapy.
Date Issued
2021-05-25
Date Acceptance
2021-03-08
Citation
ACS Nano, 2021, 15 (5), pp.8095-8109
ISSN
1936-0851
Publisher
American Chemical Society
Start Page
8095
End Page
8109
Journal / Book Title
ACS Nano
Volume
15
Issue
5
Copyright Statement
© 2021 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Nano, after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsnano.0c04489
Sponsor
Commission of the European Communities
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/33724778
Grant Number
676137
Subjects
cellular delivery
endosomal escape
nanomedicine
nano−bio interface
pulmonary surfactant
siRNA
Publication Status
Published
Coverage Spatial
United States
Date Publish Online
2021-03-16