Cytosolic delivery of nucleic acids: The case of ionizable lipid nanoparticles

Ionizable lipid nanoparticles (LNPs) are the most clinically advanced nano-delivery system for therapeutic nucleic acids. The great effort put in the development of ionizable lipids with increased in vivo potency brought LNPs from the laboratory benches to the FDA approval of patisiran in 2018 and the ongoing clinical trials for mRNA-based vaccines against SARS-CoV-2. Despite these success stories, several challenges remain in RNA delivery, including what is known as "endosomal escape." Reaching the cytosol is mandatory for unleashing the therapeutic activity of RNA molecules, as their accumulation in other intracellular compartments would simply result in efficacy loss. In LNPs, the ability of ionizable lipids to form destabilizing non-bilayer structures at acidic pH is recognized as the key for endosomal escape and RNA cytosolic delivery. This is motivating a surge in studies aiming at designing novel ionizable lipids with improved biodegradation and safety profiles. In this work, we describe the journey of RNA-loaded LNPs across multiple intracellular barriers, from the extracellular space to the cytosol. In silico molecular dynamics modeling, in vitro high-resolution microscopy analyses, and in vivo imaging data are systematically reviewed to distill out the regulating mechanisms underlying the endosomal escape of RNA. Finally, a comparison with strategies employed by enveloped viruses to deliver their genetic material into cells is also presented. The combination of a multidisciplinary analytical toolkit for endosomal escape quantification and a nature-inspired design could foster the development of future LNPs with improved cytosolic delivery of nucleic acids

CRISPR-Cas9 genome editing using targeted lipid nanoparticles for cancer therapy

CRISPR lipid nanoparticles promote in vivo therapeutic genome editing in two aggressive cancer mouse models.</jats:p

Polysarcosine-Functionalized Lipid Nanoparticles for Therapeutic mRNA Delivery

Polysarcosine (pSar) is a polypeptoid based on the endogenous amino acid sarcosine (N-methylated glycine), which has previously shown potent stealth properties. Here, lipid nanoparticles (LNPs) for therapeutic application of messenger RNA were assembled using pSarcosinylated lipids as a tool for particle engineering. Using pSar lipids with different polymeric chain lengths and molar fractions enabled the control of the physicochemical characteristics of the LNPs, such as particle size, morphology, and internal structure. In combination with a suited ionizable lipid, LNPs were assembled, which displayed high RNA transfection potency with an improved safety profile after intravenous injection. Notably, a higher protein secretion with a reduced immunostimulatory response was observed when compared to systems based on polyethylene glycol (PEG) lipids. pSarcosinylated nanocarriers showed a lower proinflammatory cytokine secretion and reduced complement activation compared to PEGylated LNPs. In summary, the described pSar-based LNPs enable safe and potent delivery of mRNA, thus signifying an excellent basis for the development of PEG-free RNA therapeutics

Nickel(II) dithiocarbamate complexes containing sulforhodamine B as fluorescent probes for selective detection of nitrogen dioxide

10.1021/ja401555yJournal of the American Chemical Society135145312-5315JACS