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University of Texas Southwestern Medical Center
Neurophysiology Laboratory
Chris Phillips Research Technician
Melissa Fowler Graduate student
Emin Ozkan Graduate Student
Nanotransfection: Nanoparticle-mediated non viral gene delivery
Despite the enticing promise of gene-delivery systems for gene therapy, to date the results have been disappointing, with only a handful of patients as of a couple years ago showing clinical benefit despite over 3000 people treated for a variety of conditions. Although the concept of gene therapy is sound, the problem lies with the efficient delivery of specific genetic material selectively into diseased cells. Viral vector based gene therapy has been used to modify or replace defective genes and has shown potential as a method of treating disease in animal models. But the enthusiasm for the use of viral-mediated gene delivery in humans has been dampened by safety concerns and fatalities in clinical trials. As an alternative, non-viral deliver systems have been proposed and many variants are now available commercially. However, the available formulations have drawbacks such as low in-vivo transfection efficiency, poor targeting specificity, and cytotoxicity at the optimal concentrations for transfection. We propose a new class of multi-functional nanoparticles for in-vivo delivery and transfection of DNA to cultured cells and neurons with a high level of efficiency. The nanoparticle size, porosity, and charge can be independently controlled to optimize each characteristic to target and deliver DNA to various cell types. A drug-loadable core with a tunable release profile will deliver transfection enhancing compounds to the cell or will be loaded with fluorescent molecules to allow the progress of the nanoparticle through different cellular components to be monitored. This nanoparticle-based delivery system has been used to transfect HEK 293 cells with enhanced green fluorescent protein (EGFP) in vitro and mouse neurons in vivo. For the mouse experiment, the nanoparticle reagents demonstrated higher neuronal transfection rates than Lipofectamine, a popular commercial reagent.
Top panels show two different nanoparticle formulations with 50nm (left) and 95nm (right) sizes Bottom right panel shows HEK 293 cells nanotransfected with 50 nm nanoparticle/Green fluorescent protein DNA plasmid. Left panel shows in vivo nanotransfection of GFP into the brain nucleus accumbens region of an adult c57 mouse.
Wednesday, April 12, 2006
Awards · 2006-08 NARSAD Young Investigator Award Molecular mechanisms controlling neuronal excitability in the hippocampal/prefrontal cortical pathway: The role of TRPC channels in schizophrenia · 2005-2010 K-01 NIH NIDA Award DNA microarray analysis of neuronal excitability
Chan Nguyen Graduate student
Ammar Hawasli Graduate student
Patch-clamp recording of a pyramidal neuron
Electrophysiologists in Training
Favorite Open Access Journals
Contact Information Don Cooper UT Southwestern Medical Center Dept of Psychiatry 2201 Inwood Rd NC 5.122A Dallas, TX 75390-9070 Ph 214-648-5955 Email: Don.Cooper@utsouthwestern.edu
The CA1 to Subiculum transition Don Cooper and Leah Leverich
Positions Available Graduate student Postdoctoral Fellow
The long-term goals of the laboratory are to understand information processing in the brain motivation/reward memory circuitry and characterize the adaptations and impaired neural decision-making associated with addiction and schizophrenia.
Despite a rather detailed understanding of the various transmitters and anatomical connections, there is lacking a fundamental understanding of how neurons within the hippocampal/frontal cortical circuit integrate synaptic and modulatory input along their somatodendritic axis in order to establish appropriately patterned action potential output. Even less is known about psychosis- and addiction-associated neuroadaptations that follow repeated exposure to drugs like psychostimulants. Transient and persistent drug-induced modulation of the moment-to-moment pattern and rate of action potential activity within hippocampal/prefrontal cortical pathway may underlie the impaired decision-making and loss of behavioral control associated with psychosis and addiction.
As a neurophysiology laboratory our goal is to combine behavioral, molecular genetic and detailed electrophysiological analysis to understand how psychostimulant drugs alter neuronal impulse activity leading to short and long-term changes in the ability of neurons within the mesolimbic dopamine system to communicate. Our approach to this problem utilizes state-of-the-art technology (e.g. DNA microarrays, dendritic Ca++ imaging, infrared and fluorescence visualized patch-clamp physiology and intravenous drug self-administration) and complementary levels of analysis (e.g. behavior, in vivo and in vitro physiology, molecular techniques and computer simulation) in order to gain insight into how this system functions under normal and pathological conditions.