There is currently a surge of activity in developing virus-free lipid-based gene delivery systems for therapeutic applications because of their low toxicity, nonimmunogenicity, and ease of production. Cationic liposome-DNA (CL-DNA) complexes have shown gene expression in vivo in targeted organs, and human clinical protocols are ongoing. These lipid-gene complexes have the potential of transferring large pieces of DNA into cells. Indeed, partial fractions of order 1 million base-pairs of human artificial chromosome have been transferred into cells using cationic lipids as a vector although extremely inefficiently. Because our understanding of the mechanisms of action of CL-DNA complexes remains poor, transfection efficiencies are very low compared to gene delivery with viral vectors. The low transfection efficiencies with virus-free delivery methods are the result of poorly understood transfection-related mechanisms at the molecular and supramolecular levels, and a general lack of knowledge of interactions of lipid-gene complexes with components inside cells which lead to gene release and expression.
The aims of this research application are (1) to clarify the relation between the physical and chemical parameters of CL-DNA complexes with a distinct nanostructure, and transfection efficiency in mammalian cells, and (2) to determine the nanostructures and transfection efficiency properties of a new class of surface-functionalized CL-DNA complexes, which are designed for specific interactions with cellular components. The structure of the lipid-gene complexes will be solved by using state-of the-art synchrotron x-ray diffraction techniques at the Stanford Synchrotron Radiation Laboratory. Laser scanning confocal microscopy will enable us to track the CL-DNA particles and observe their interactions with cells. The structures will be correlated to transfection efficiencies by modern molecular biology methods of quantitatively measuring expression of the luciferase reporter gene in mammalian cells. The broad long-range goal of the research is to develop optimal synthetic virus-free carriers of DNA for gene therapy and disease control.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
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Biophysical Chemistry Study Section (BBCB)
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Chin, Jean
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University of California Santa Barbara
Engineering (All Types)
Schools of Engineering
Santa Barbara
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Wonder, Emily; Simón-Gracia, Lorena; Scodeller, Pablo et al. (2018) Competition of charge-mediated and specific binding by peptide-tagged cationic liposome-DNA nanoparticles in vitro and in vivo. Biomaterials 166:52-63
Steffes, Victoria M; Murali, Meena M; Park, Yoonsang et al. (2017) Distinct solubility and cytotoxicity regimes of paclitaxel-loaded cationic liposomes at low and high drug content revealed by kinetic phase behavior and cancer cell viability studies. Biomaterials 145:242-255
Majzoub, Ramsey N; Ewert, Kai K; Safinya, Cyrus R (2016) Cationic liposome-nucleic acid nanoparticle assemblies with applications in gene delivery and gene silencing. Philos Trans A Math Phys Eng Sci 374:
Safinya, Cyrus R; Chung, Peter J; Song, Chaeyeon et al. (2016) The effect of multivalent cations and Tau on paclitaxel-stabilized microtubule assembly, disassembly, and structure. Adv Colloid Interface Sci 232:9-16
Majzoub, Ramsey N; Wonder, Emily; Ewert, Kai K et al. (2016) Rab11 and Lysotracker Markers Reveal Correlation between Endosomal Pathways and Transfection Efficiency of Surface-Functionalized Cationic Liposome-DNA Nanoparticles. J Phys Chem B 120:6439-53
Majzoub, Ramsey N; Ewert, Kai K; Safinya, Cyrus R (2016) Quantitative Intracellular Localization of Cationic Lipid-Nucleic Acid Nanoparticles with Fluorescence Microscopy. Methods Mol Biol 1445:77-108
Ewert, Kai K; Kotamraju, Venkata Ramana; Majzoub, Ramsey N et al. (2016) Synthesis of linear and cyclic peptide-PEG-lipids for stabilization and targeting of cationic liposome-DNA complexes. Bioorg Med Chem Lett 26:1618-1623
Majzoub, Ramsey N; Ewert, Kai K; Jacovetty, Erica L et al. (2015) Patterned Threadlike Micelles and DNA-Tethered Nanoparticles: A Structural Study of PEGylated Cationic Liposome-DNA Assemblies. Langmuir 31:7073-83
Majzoub, Ramsey N; Chan, Chia-Ling; Ewert, Kai K et al. (2015) Fluorescence microscopy colocalization of lipid-nucleic acid nanoparticles with wildtype and mutant Rab5-GFP: A platform for investigating early endosomal events. Biochim Biophys Acta 1848:1308-18
Ojeda-Lopez, Miguel A; Needleman, Daniel J; Song, Chaeyeon et al. (2014) Transformation of taxol-stabilized microtubules into inverted tubulin tubules triggered by a tubulin conformation switch. Nat Mater 13:195-203

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