Document text
Principal Investigator: Cecilia Maria Leal
Organization: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
Fiscal Year: 2023
Award: $377,007
Funding agency: National Institute of General Medical Sciences
PROJECT SUMMARY
RNA therapeutics hold great promise for the treatment of a number of diseases significantly impacting human
health, such as chronic infections, genetic disorders, certain cancers, and presently COVID-19. The leading RNA
delivery vehicles approved by the FDA, as well as being considered in several clinical trials, are non-viral lipid-
based nanoparticles (LNPs). State-of-the art LNPs comprise standard phospholipids, cholesterol, and ionizable
lipids (ILs) that get protonated in acidic conditions. Analogous to enveloped virus, LNPs hijack the endocytic
pathway to enter cells. The efficacy of RNA delivery hinges on the ability of LNPs to escape the endosome by
fusing with its membrane. However, the factors that control LNPs–endosome fusion remain largely unknown.
Enveloped viruses contain proteins that promote fusion by stabilizing the formation of highly curved membrane
pores. In LNPs, alternative strategies to bolster fusion include using lipids with non-zero spontaneous curvature
that are elusively deemed “fusogenic”. However, understanding membrane fusion requires the consideration of
membrane elasticity beyond spontaneous curvature. Specifically, the formation of a fusion pore between two
bilayers is dictated by an interplay between the bending modulus and the Gaussian curvature modulus. However,
the Gaussian modulus is rarely considered when designing “fusogenic” LNPs, even though bilayer fusion is an
occasion for which its value matters the most.
The central hypothesis of this work is that raising the Gaussian modulus of LNPs by inclusion of a new class of
lipids termed Gaussian curvature lipids (GCLs) has a dramatic effect on the ability of LNPs to fuse with
endosomal membranes. Furthermore, we conjecture that membrane fusion, as boosted by GCL integration, is
synergistically favored in living systems during active proton pumping and endosome acidification.
We combine a team of experts in RNA delivery to cells, membrane protein purification as well as experimental,
computational, and theoretical membrane elasticity to test the central hypotheses via two aims. In Aim 1 we will
establish the biophysical elastic properties of LNPs to maximize fusion with endosomes. We investigate how
fusion takes place at a microscopic level, namely deciphering if the dominant effect is the formation of fusion
pores and/or if LNPs feed lipids to endosomal membranes remodeling them and making them more prone to
rupture. In Aim 2 we investigate the impact of membrane activity and endosome acidification by measuring in
live cells RNA delivery and endosomal fusion of LNPs comprising increasing amounts of GCLs. We will also
develop endosome-mimetic vesicular systems reconstituted with endosomal membrane proton pumps (V-
ATPase) to elucidate the mechanism of LNP-endosomal membrane fusion during active proton pumping.
Our work will raise new physical insights on LNP endosomal escape and establish the desired LNP membrane
properties to boost fusion in living systems, resulting in substantially more effective RNA delivery vehicles.
Terms: <2019-nCoV vaccine><Affect><Assay><Baker's Yeast><Binding><Bioassay><Biologic Assays><Biological Assay><Biophysics><Brewer's Yeast><COVID-19><COVID-19 vaccine><COVID19><COVID19 vaccine><CV-19><CV19><Cancers><Cell Body><Cell Line><CellLine><Cells><Cholesterol><Clinical><Clinical Trials><Communication><Confocal Microscopy><Cryo-electron Microscopy><Cryoelectron Microscopy><Cytosol><DNA delivery><Data><Diffuse><Disease><Disorder><Drug Delivery><Drug Delivery Systems><Elasticity><Electron Cryomicroscopy><Endocytosis Pathway><Endocytotic role of NDK, Phosphins and Dynamin><Endosomes><Eukaryotic Cell><Evaluation><Event><Evolution><FDA approved><FRET><Flow Cytofluorometries><Flow Cytofluorometry><Flow Cytometry><Flow Microfluorimetry><Flow Microfluorometry><Fluorescence Resonance Energy Transfer><Formulation><Förster Resonance Energy Transfer><Gene Delivery><Generations><Genetic Diseases><Goals><H(+) Pump><H+ Pump><Health><Human><Label><Lipids><Malignant Neoplasms><Malignant Tumor><Measures><Membrane><Membrane Fusion><Membrane Protein Gene><Membrane Proteins><Membrane-Associated Proteins><Messenger RNA><Microfluidics><Microscopic><Modeling><Modern Man><Modulus><Molecular><Molecular Interaction><Molecular Modeling Nucleic Acid Biochemistry><Molecular Modeling Protein/Amino Acid Biochemistry><Molecular Models><Nucleic Acids><Organism><Pathway interactions><Phase><Phosphatides><Phospholipids><Process><Property><Proteins><Proton Pump><RNA based therapeutics><RNA based therapy><RNA delivery><RNA therapy><Receptosomes><Research Support><Roentgen Rays><Role><Rupture><S cerevisiae><S. cerevisiae><SARS-CoV-2 vaccine><SARS-CoV2 vaccine><SARS-coronavirus-2 vaccine><Saccharomyces cerevisiae><Series><Severe Acute Respiratory Syndrome CoV 2 vaccine><Severe acute respiratory syndrome coronavirus 2 vaccine><Spectroscopy><Spectrum Analyses><Spectrum Analysis><Strains Cell Lines><Stress><Surface Proteins><Swelling><System><Testing><Therapeutic><V-ATPase><V-type ATPase><Virus><Work><X-Radiation><X-Ray Radiation><X-ray><Xray><Yeasts><biophysical foundation><biophysical principles><biophysical sciences><cell type><chronic infection><corona virus disease 2019><corona virus disease 2019 vaccine><coronavirus disease 2019><coronavirus disease 2019 vaccine><coronavirus disease-19><coronavirus disease-19 vaccine><coronavirus infectious disease-19><cryo-EM><cryoEM><cryogenic electron microscopy><cultured cell line><deliver DNA><delivery vector><delivery vehicle><design><designing><endosome lumen><endosome membrane><experiment><experimental research><experimental study><experiments><flow cytophotometry><fluorophore><genetic condition><genetic disorder><innovate><innovation><innovative><insight><interdisciplinary approach><lipid based nanoparticle><lipid nanoparticle><living system><mRNA><mRNA delivery><malignancy><membrane activity><membrane structure><microscope imaging><microscopic imaging><microscopy imaging><mimetics><model-based simulation><models and simulation><molecular modeling><multidisciplinary approach><nCoV vaccine><nCoV-19 vaccine><nCoV19 vaccine><nano particle delivery><nanoparticle delivered><nanoparticle delivery><neoplasm/cancer><new approaches><novel approaches><novel strategies><novel strategy><pathway><persistent infection><protein expression><protein purification><reconstitute><reconstitution><simulation><social role><therapeutic RNA><unilamellar vesicle><vaccine against 2019-nCov><vaccine against SARS-CoV-2><vaccine against SARS-CoV2><vaccine against SARS-coronavirus-2><vaccine against Severe Acute Respiratory Syndrome CoV 2><vaccine against Severe acute respiratory syndrome coronavirus 2><vaccine for novel coronavirus><vacuolar ATPase><vacuolar H+-ATPase><vacuolar membrane H(+)-ATPase><µfluidic>