Stereochemistry of Lipid Nanoparticles Significantly Affects Protein Expression and Drug Delivery Efficiency
Researchers systematically varied the stereochemistry of each lipid component in lipid nanoparticles (LNPs) and found that molecular handedness across all components — not just the ionizable lipid — significantly affects RNA delivery and protein expression. The study used cryo-TEM imaging, SAXS structural analysis, and testing across six cell lines plus zebrafish and mouse models to link stereochemical identity to internal lipid phase organization. The findings suggest that stereochemical optimization of LNPs as a whole could be a largely untapped lever for improving mRNA therapeutics and vaccines.
A new preprint on bioRxiv reports that the stereochemical identity of lipid nanoparticles — the three-dimensional arrangement of atoms in each lipid component — is a key but underappreciated determinant of RNA delivery efficiency. The researchers separated the ionizable lipid cKK-E12 into its cis (R,R/S,S) and trans (R,S/S,R) stereoisomers, which are normally used as an undifferentiated mixture, and found that LNPs built with the cis isomer showed superior physicochemical properties, stability, and protein expression. Going further, they systematically varied the stereochemistry of not only the ionizable lipid but also the phospholipid and cholesterol components, revealing stereochemistry-dependent differences in cellular uptake and protein expression across six cell lines and in vivo in zebrafish embryos and mice. AI-assisted cryo-transmission electron microscopy and small-angle X-ray scattering (SAXS) linked these functional differences to distinct internal lipid phase structures — specifically lamellar versus inverse hexagonal arrangements — and to differences in particle uniformity. The work challenges the field's conventional focus on ionizable lipid chemistry alone and positions the overall stereochemical identity of the LNP as a tunable design parameter for next-generation RNA delivery systems.
What's missing
As a preprint, this work has not yet undergone formal peer review. The study does not report direct comparisons to clinically approved LNP formulations (e.g., those used in COVID-19 mRNA vaccines), leaving the translational magnitude of the stereochemical effect relative to current standards unclear. The scalability and cost of producing stereochemically pure lipid components at pharmaceutical scale is not addressed.
What different sources said
- bioRxivCenter
Stereochemical identity of lipid nanoparticles modulates protein expression via internal lipid organization
Related
Gut Bacteria Enzyme Found to Break Down Heat-Processed Food Compounds, Producing Novel Biogenic Amines
Researchers have discovered that an enzyme in common gut bacteria can degrade N-epsilon-carboxymethyllysine (CML), a compound formed during thermal food processing, producing previously unknown biogenic amines. The enzyme, ornithine decarboxylase SpeC from enterobacteria, acts on CML and related modified lysine derivatives through a low-level 'underground' catalytic activity. This finding suggests a previously unrecognized communication axis between thermally processed dietary compounds and gut microbial physiology, with potential implications for host health.
Full-Length Gene Sequencing Reveals Two Distinct Bacterial Communities in Black-Legged Ticks Expanding Into Canada
Researchers used Oxford Nanopore full-length 16S rRNA gene sequencing to characterize the microbiome of Ixodes scapularis black-legged ticks collected in Nova Scotia, Canada, distinguishing between tick-adapted bacteria and environmentally acquired bacteria. The study comes as I. scapularis — the primary vector of Lyme disease — is rapidly expanding northward into Canada due to climate change. The findings suggest that environmentally derived bacteria in tick microbiomes are not mere contamination, which has implications for how tick microbiome data is collected and interpreted across surveillance studies.
Study Identifies Metabolic Link Between Cell Envelope Stress and Biofilm Formation in Bacteria
Researchers have discovered that the metabolite acetyl-CoA directly inhibits enzymes that degrade the bacterial signaling molecule c-di-GMP, connecting cell envelope biosynthesis stress to biofilm formation in Pseudomonas aeruginosa. The study found that sub-inhibitory concentrations of antibiotics targeting early peptidoglycan biosynthesis — but not other antibiotic classes — elevate c-di-GMP levels by reducing phosphodiesterase activity, with acetyl-CoA competing for the enzyme active site. Because the relevant enzyme domain is broadly conserved across bacterial species, this checkpoint mechanism may be widespread and could have implications for understanding antibiotic-induced biofilm responses.