In recent months, scientists have been testing a potential treatment for COVID-19 that works to destroy viral DNA inside of a patient’s lungs. This new therapy utilizes an established gene editing tool called CRISPR.
CRISPR is a genome editing tool that allows scientists to alter the DNA or RNA of an organism. In essence, the CRISPR system works by utilizing specific enzymes that can cut RNA into fragments. These enzymes are programmed in a lab so that they become predisposed to recognize and cleave certain RNA sequences. When a viral RNA is destroyed through this system, the virus becomes disabled and its potential to infect living cells will be limited. In the past year, researchers have been developing and testing a CRISPR-based mechanism to fight viral infections, called Pac-Man.
Prophylactic Antiviral CRISPR in Human
Pac-Man, which stands for Prophylactic Antiviral CRISPR in human cells, was originally developed by assistant professor Stanley Qi of Stanford University as a tool fight influenza. When the pandemic hit the U.S back in January, Qi and his team decided to try out the Pac-Man system on the coronavirus. During this process, the researchers had to direct the enzyme present in the Pac-Man system to recognize and cleave coronavirus RNA. To do this, Qi and his team analyzed coronavirus DNA to find two genes that appeared frequently across all viral genomes. When the Pac-Man system was used to target synthetic sequences of these genes, researchers found that the enzymes greatly reduced the presence of the RNA sequences.
Unfortunately, there is still much to do before Pac-Man can be used to treat human patients afflicted with COVID-19. One of the biggest challenges to overcome is finding a method to deliver the system into a patient’s lungs. One of the ways that researchers are looking into solving this issue is through the use of a substance called a lipitoid. Lipitoids are a synthetic molecule that have the capacity to self-assemble with DNA and RNA. This ability allows lipitoids to deliver DNA and RNA to an array of different cells. This, alongside the fact that lipitoids are nontoxic, gives the molecules promise in their potential to deliver the Pac-Man system to a patient’s lungs.
In April of 2020, scientists found that a certain type of lipitoid, called lipitoid 1, was able to assemble with RNA and Pac-Man inside of human lung cells to reduce concentrations of synthetic coronavirus DNA by over 90%. After the success of this study, researchers plan to begin testing Pac-Man in animal subjects that have been infected by a live coronavirus strain.