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Noninvasive aerosol inhalation is an established method of drug delivery to the lung, and remains a desirable route for nucleic-acid-based therapeutics. In vitro transcribed (IVT) mRNA has broad therapeutic applicability as it permits temporal and dose-dependent control of encoded protein expression. Inhaled delivery of IVT-mRNA has not yet been demonstrated and requires development of safe and effective materials. To meet this need, hyperbranched poly(beta amino esters) (hPBAEs) are synthesized to enable nanoformulation of stable and concentrated polyplexes suitable for inhalation. This strategy achieves uniform distribution of luciferase mRNA throughout all five lobes of the lung and produces 101.2 ng g -1 of luciferase protein 24 h after inhalation of hPBAE polyplexes. Importantly, delivery is localized to the lung, and no luminescence is observed in other tissues. Furthermore, using an Ai14 reporter mouse model it is identified that 24.6% of the total lung epithelial cell population is transfected after a single dose. Repeat dosing of inhaled hPBAE-mRNA generates consistent protein production in the lung, without local or systemic toxicity. The results indicate that nebulized delivery of IVT-mRNA facilitated by hPBAE vectors may provide a clinically relevant delivery system to lung epithelium., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

mRNA therapeutics hold great potential for treating a variety of diseases through protein-replacement, immunomodulation, and gene editing. However, much like siRNA therapy the majority of progress in mRNA delivery has been confined to the liver. Previously, we demonstrated that poly(β-amino esters), a class of degradable polymers, are capable of systemic mRNA delivery to the lungs in mice when formulated into nanoparticles with poly(ethylene glycol)-lipid conjugates. Using experimental design, a statistical approach to optimization that reduces experimental burden, we demonstrate herein that these degradable polymer-lipid nanoparticles can be optimized in terms of polymer synthesis and nanoparticle formulation to achieve a multiple order-of-magnitude increase in potency. Furthermore, using genetically engineered Cre reporter mice, we demonstrate that mRNA is functionally delivered to both the lung endothelium and pulmonary immune cells, expanding the potential utility of these nanoparticles.

RNAs are a promising class of therapeutics given their ability to regulate protein concentrations at the cellular level. Developing safe and effective strategies to deliver RNAs remains important for realizing their full clinical potential. Here, we develop lipid nanoparticle formulations that can deliver short interfering RNAs (for gene silencing) or messenger RNAs (for gene upregulation). Specifically, we study how the tail length, tail geometry, and linker spacing in diketopiperazine lipid materials influences LNP potency with siRNAs and mRNAs. Eight lipid materials are synthesized, and 16 total formulations are screened for activity in vitro; the lead material is evaluated with mRNA for in vivo use and demonstrates luciferase protein expression in the spleen. In undertaking this approach, not only do we develop synthetic routes to delivery materials, but we also reveal structural criteria that could be useful for developing next-generation delivery materials for RNA therapeutics., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Nucleic acid therapeutics are limited by inefficient delivery to target tissues and cells and by an incomplete understanding of how nanoparticle structure affects biodistribution to off-target organs. Although thousands of nanoparticle formulations have been designed to deliver nucleic acids, most nanoparticles have been tested in cell culture contexts that do not recapitulate systemic in vivo delivery. To increase the number of nanoparticles that could be tested in vivo, we developed a method to simultaneously measure the biodistribution of many chemically distinct nanoparticles. We formulated nanoparticles to carry specific nucleic acid barcodes, administered the pool of particles, and quantified particle biodistribution by deep sequencing the barcodes. This method distinguished previously characterized lung- and liver- targeting nanoparticles and accurately reported relative quantities of nucleic acid delivered to tissues. Barcode sequences did not affect delivery, and no evidence of particle mixing was observed for tested particles. By measuring the biodistribution of 30 nanoparticles to eight tissues simultaneously, we identified chemical properties promoting delivery to some tissues relative to others. Finally, particles that distributed to the liver also silenced gene expression in hepatocytes when formulated with siRNA. This system can facilitate discovery of nanoparticles targeting specific tissues and cells and accelerate the study of relationships between chemical structure and delivery in vivo.

mRNA has broad potential for treating diseases requiring protein expression. However, mRNA can also induce an immune response with associated toxicity. Replacement of uridine bases with pseudouridine has been postulated to modulate both mRNA immunogenicity and potency. Here, we explore the immune response and activity of lipid nanoparticle-formulated unmodified and pseudouridine-modified mRNAs administered systemically in vivo. Pseudouridine modification to mRNA had no significant effect on lipid nanoparticle physical properties, protein expression in vivo, or mRNA immunogenicity compared to unmodified mRNA when delivered systemically with liver-targeting lipid nanoparticles, but reduced in vitro transfection levels. Indicators of a transient, extracellular innate immune response to mRNA were observed, including neutrophilia, myeloid cell activation, and up-regulation of four serum cytokines. This study provides insight into the immune responses to mRNA lipid nanoparticles, and suggests that pseudouridine modifications may be unnecessary for therapeutic application of mRNA in the liver., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Therapeutic nucleic acids hold great promise for the treatment of disease but require vectors for safe and effective delivery. Synthetic nanoparticle vectors composed of poly(β-amino esters) (PBAEs) and nucleic acids have previously demonstrated potential utility for local delivery applications. To expand this potential utility to include systemic delivery of mRNA, hybrid polymer-lipid nanoformulations for systemic delivery to the lungs were developed. Through coformulation of PBAEs with lipid-polyethylene glycol (PEG), mRNA formulations were developed with increased serum stability and increased in vitro potency. The formulations were capable of functional delivery of mRNA to the lungs after intravenous administration in mice. To our knowledge, this is the first report of the systemic administration of mRNA for delivery to the lungs using degradable polymer-lipid nanoparticles., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Thousands of human diseases could be treated by selectively controlling the expression of specific proteins in vivo. A new series of alkenyl amino alcohol (AAA) ionizable lipid nanoparticles (LNPs) capable of delivering human mRNA with unprecedented levels of in vivo efficacy is demonstrated. This study highlights the importance of utilizing synthesis tools in tandem with biological inspiration to understand and improve nucleic acid delivery in vivo., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Intracellular delivery of messenger RNA (mRNA) has the potential to induce protein production for many therapeutic applications. Although lipid nanoparticles have shown considerable promise for the delivery of small interfering RNAs (siRNA), their utility as agents for mRNA delivery has only recently been investigated. The most common siRNA formulations contain four components: an amine-containing lipid or lipid-like material, phospholipid, cholesterol, and lipid-anchored polyethylene glycol, the relative ratios of which can have profound effects on the formulation potency. Here, we develop a generalized strategy to optimize lipid nanoparticle formulations for mRNA delivery to the liver in vivo using Design of Experiment (DOE) methodologies including Definitive Screening and Fractional Factorial Designs. By simultaneously varying lipid ratios and structures, we developed an optimized formulation which increased the potency of erythropoietin-mRNA-loaded C12-200 lipid nanoparticles 7-fold relative to formulations previously used for siRNA delivery. Key features of this optimized formulation were the incorporation of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and increased ionizable lipid:mRNA weight ratios. Interestingly, the optimized lipid nanoparticle formulation did not improve siRNA delivery, indicating differences in optimized formulation parameter design spaces for siRNA and mRNA. We believe the general method described here can accelerate in vivo screening and optimization of nanoparticle formulations with large multidimensional design spaces.

Small interfering RNAs (siRNAs) can specifically inhibit gene expression. As a result, they have tremendous scientific and clinical potential. However, the use of these molecules in patients and animal models has been limited by challenges with delivery. Intracellular RNA delivery is difficult; it requires a system that protects the siRNA from degradative nucleases in the bloodstream, minimizes clearance by the reticuloendothelial system, maximizes delivery to the target tissue, and promotes entry into, and out of, an endocytic vesicle. Despite these barriers, recent data suggest that RNA may be targeted to cells of interest in vivo. Herein we outline strategies for targeted siRNA delivery, and describe how these strategies may be improved.

Nucleic acid therapeutics are limited by inefficient delivery to target tissues and cells and by an incomplete understanding of how nanoparticle structure affects biodistribution to off-target organs. Although thousands of nanoparticle formulations have been designed to deliver nucleic acids, most nanoparticles have been tested in cell culture contexts that do not recapitulate systemic in vivo delivery. To increase the number of nanoparticles that could be tested in vivo, we developed a method to simultaneously measure the biodistribution of many chemically distinct nanoparticles. We formulated nanoparticles to carry specific nucleic acid barcodes, administered the pool of particles, and quantified particle biodistribution by deep sequencing the barcodes. This method distinguished previously characterized lung- and liver-targeting nanoparticles and accurately reported relative quantities of nucleic acid delivered to tissues. Barcode sequences did not affect delivery, and no evidence of particle mixing was observed for tested particles. By measuring the biodistribution of 30 nanoparticles to eight tissues simultaneously, we identified chemical properties promoting delivery to some tissues relative to others. Finally, particles that distributed to the liver also silenced gene expression in hepatocytes when formulated with siRNA. This system can facilitate discovery of nanoparticles targeting specific tissues and cells and accelerate the study of relationships between chemical structure and delivery in vivo. [ABSTRACT FROM AUTHOR]

Therapeutic nucleic acids hold great promise for the treatment of disease but require vectors for safe and effective delivery. Synthetic nanoparticle vectors composed of poly(β-amino esters) (PBAEs) and nucleic acids have previously demonstrated potential utility for local delivery applications. To expand this potential utility to include systemic delivery of mRNA, hybrid polymer-lipid nanoformulations for systemic delivery to the lungs were developed. Through coformulation of PBAEs with lipid-polyethylene glycol (PEG), mRNA formulations were developed with increased serum stability and increased in vitro potency. The formulations were capable of functional delivery of mRNA to the lungs after intravenous administration in mice. To our knowledge, this is the first report of the systemic administration of mRNA for delivery to the lungs using degradable polymer-lipid nanoparticles. [ABSTRACT FROM AUTHOR]