Once DNA enters the cell by any method, a number of barriers must be overcome in order for any transgene expression to occur. We have spent a number of years characterizing the events and mechanisms of plasmid intracellular trafficking with focus on movement through the cytoplasm, into the nucleus, and within the nucleus. We have also investigated whether and how these mechanisms contribute to effective gene transfer and expression. Based on these studies, we have developed several novel approaches to increase gene transfer in vitro and in vivo as well as to confer cell-specificity. These include the use of DNA nuclear targeting sequences to promote nuclear entry of plasmid-DNA complexes, the use of DNA sequences to promote formation of protein-DNA complexes that bind to molecular motors for movement along microtubules, modulation of microtubule post-translational modification to enhance movement of plasmids to the nucleus, and methods for cell entry of the DNA. I will discuss some of these approaches and their exploitation for development of an electroporation-based gene therapy treatment for acute lung injury, a disease with a current mortality of around 30% that kills approximately 75,000 people yearly in the US. This disease results from a number of different stimuli, all of which induce significant inflammation in the lung, breakdown of the alveolar-capillary permeability barrier, accumulation of pulmonary edema, and ultimately reduced gas exchange. Our studies have lead to the development of a rational gene therapy treatment using the b1 subunit of the Na+,K+-ATPase to improve all of these issues in both small and large animal preclinical models.
David Dean interests are in understanding how things move from one place to another and across membranes in cells. I received my PhD at UC Berkeley in 1990 working on sugar transport in E. coli and then did postdoctoral work at UCLA on SV40 nuclear import and viral assembly. My first faculty position was in the Department of Microbiology and Immunology at the University of South Alabama College of Medicine, where I turned my attention to understanding how plasmids enter the nulcei of non-dividing (and dividing) cells.
My lab has characterized several DNA sequences that mediate nuclear import of plasmids and have shown that they can increase the efficiency and specificity of gene delivery both in cells and in whole animal models of disease. In 2000, I moved my laboratory to the Division of Pulmonary and Critical Care Medicine at the Feinberg School of Medicine at Northwestern University in Chicago and began to apply our findings to gene therapy in the lung. Here I developed a productive, diversified laboratory studying various aspects of DNA delivery and intracellular trafficking. Concentrating on applications to gene therapy of pulmonary and vascular disease, we developed electroporation strategies for gene delivery to the lung and vasculature. While in Chicago, our main emphasis turned to addressing diseases of the lung, including acute lung injury and acute respiratory distress syndrome (ALI/ARDS) and asthma. In 2007, I relocated to the Division of Neonatology at the University of Rochester in upstate New York. Our group is developing new methods for gene delivery to the lungs and defining the molecular details of delivery approaches that will ultimately lead to treatments for these devastating diseases.