Grant: CIHR Fellowship

Gene therapy, namely the modulation of gene expression in target cells to treat disease, is accomplished by the introduction of exogenous nucleic acids into target tissue sites. Indeed, this approach has shown great potential in cancer and cardiovascular disease (CVD), e.g. the delivery of pro-angiogenic factors in ischemia applications. The success of gene therapy strongly hinges on a delivery platform to allow access of these large macromolecules to the disease site. Viral vectors, while able to provide efficient delivery, often elicit strong immune responses that limit its clinical impact. To address this, our lab has developed intravenously injected nucleic acid loaded microbubble (MB) contrast agents which can be targeted to deliver their payloads by direct navigation of an ultrasound beam (US) to the target tissue. While met with promising success, this approach (sonoporation) is less efficient compared to viral methods, in large part due to an incomplete understanding of the biophysics of sonoporation. The objective of this proposal is to substantiate the merit of sonoporation as a non-viral, localized, gene delivery platform by taking a ground-up, mechanistic approach. Specifically, we will identify the physical mechanisms by which US-activated MBs perforate cell membranes and deliver genetic material by use of novel ultrafast microscopy. Secondly, we will assess the effects of sonoporation on cellular function using molecular assays and real-time, state-of-the-art microscopy. Finally, we will investigate the biological mechanisms by which sonoporation can access extravascular target cells by examining the integrity of cell-cell contacts. Taken together, this research program will lay the groundwork for establishing a tractable model for sonoporation, linking MB physics with the extent of local biophysical impact, in order to optimize this approach as a non-viral gene delivery platform for the treatment disease for which gene targets have been identified.