Team:Northwestern/project
Our Project
What is the problem?
Antibiotics are among the most frequently administered drugs in human medicine. However, incorrect dosing and failure to complete the prescribed course have contributed to microbes becoming resistant.
Our proposed solution
Cas9, when bound to guide RNA, results in a versatile gene editing tool that gives rise to a wide range of potential applications. Through non-homologous end joining of the double stranded break, bases are added and subtracted knocking out the gene of interest. Scientists hope to use this system to battle infectious diseases and treat multi-drug resistant microorganisms
Despite the promise behind CRISPR-Cas9, the shift from its use as a research tool to a therapeutic device poses many challenges such as undesirable host immune responses and cleavage in unwanted locations due to low system specificity. Our team is researching the use of Outer Membrane Vesicles (OMVs) as a Cas9 delivery system. We hypothesize that the successful packaging and delivery of Cas9, when combined with a specific guide RNA that defines the genomic target, could be used in a therapeutic setting to combat antibiotic resistance.
Cas9 Delivery
Typical methods for delivery of Cas9 into cell cultures include electroporation, nucleofection, and lipofectamine-mediated transfection. However, these methods work exclusively for in vitro delivery of Cas9, and not in vivo. Thus, an alternative delivery system to transport this protein to target cells is needed. Two common in vivo methods for Cas9 delivery are viral vectors and hydrodynamic injection. The latter of these two approaches resulted in both liver and cardiovascular damage to mice, and therefore does not seem viable for humans. Alternatively, bacteriophages have been effectively used for the delivery and expression of genes, but fall short in their size limitation and their potential to harm the host’s immune system. Thus, we believe that a non-viral approach is optimal and have selected OMVs as the simplest, most viable option for delivery of Cas9 as well as the guide RNA.
