What if we had the ability to cure cancer, treat blindness, develop “super” plants, or remove diseases from infectious organisms? Furthermore, what if we could accomplish all of those tasks with the power of just one technology? Clustered regularly interspaced short palindromic repeats, better known as CRISPR, is a genetic engineering technique that was thrust into the spotlight as recently as 2015 and can be used to modify the genomes of living organisms [1].
The mechanisms of CRISPR are based on the bacterial CRISPRCas9 antiviral defense system. Researchers modified RNA with a guide sequence that binds to a specific target sequence of DNA in the genome of an organism as well as the Cas9 enzyme. The Cas9 enzyme cuts the DNA at the binding location. Researchers then use the cell’s DNA repair machinery to alter components of the genetic material however they see fit [2]. This technique has been highly praised in the world of biotechnology and medicine as it enables genes to be edited in vivo (within a living organism) with very high accuracy at a low cost. As briefly mentioned earlier, its applications are incredibly extensive, which has contributed to its increasing popularity.
Fortunately, some of the immense implications of CRISPR technology have already been realized through many clinical trials that have already been performed. These trials have yielded favorable results regarding the fate of future medicine and genetic engineering. Since 2018, hundreds of clinical trials have been conducted to test the capabilities of CRISPR in treating Huntington’s disease – a neurodegenerative disease that results in the death of brain cells over time. It was determined that CRISPR could be used to remove the cytosine, adenine, and guanine repeats found in the HTT gene known to cause the disease, effectively curing it [3]. Additionally, as recent as March of this year, the FDA approved the first test of CRISPR to correct a genetic defect causing sickle cell anemia, a common blood disorder. CRISPR was used to correct the mutation in the beta-globin gene which is responsible for the disease [4]. While these trials are still underway, there have been promising results thus far.
Given our current circumstances amidst the COVID-19 pandemic, one might be inclined to ask if CRISPR could potentially play a role in vaccine development. The short answer? It already has. Both the Pfizer and Moderna vaccines are the first vaccines ever to be activated by mRNA (messenger RNA sequences), which would not have been possible without CRISPR gene-editing technology. In addition to these vaccines, there is now an increased emphasis on quick and efficient COVID testing given the likelihood of new strains of the virus arising. Recently, researchers in Singapore have developed a CRISPR-based COVID test that takes roughly thirty minutes to arrive at a positive or negative test. The test involves dipping a small paper strip into a medium containing a nasal sample. This paper strip contains a specific enzyme that will react with the virus if present.
Depending on the reaction, one or two bands will appear on the strip which indicates a negative or positive test respectively [5]. Given how quickly viruses can mutate their genetic code, rapid and accurate tests such as these are instrumental in detecting the virus early and containing its spread.
Beyond medicinal applications, CRISPR has been implemented in the creation of “super” plants – plants that transcend the capabilities of ordinary plants in promoting a sustainable environment. It is undeniable that global warming is becoming a major problem that threatens the lives of countless species across the world. Scientists have determined that the global annual temperature has increased at an approximate rate of 0.08 °C per decade since 1880. This rate has more than doubled in the last forty years with an increase of 0.18 °C per decade since 1981. In response to this major conflict, plant scientists have attempted to create plants that absorb significantly more carbon than usual by storing excess carbon dioxide in their roots. As simple as the idea sounds, on a large scale, this would remove enough carbon dioxide from the atmosphere to impede climate change substantially [6].
While it appears as if CRISPR has the potential to solve many of our ongoing and future scientific problems, there are many ethical considerations that should be noted. As beneficial as gene editing can be, it comes in many varieties and can have many consequences. For example, germline gene editing affects all cells in an organism unlike somatic gene editing which only affects some target cells. If germline editing is performed in vivo on a patient, it can affect their egg or sperm cells which can then be passed onto future generations. Such modifications could produce an unintended chain reaction of effects that result in healthy cells not functioning properly [7]. Ultimately, the consequences of this are too difficult to predict, and utmost caution should be exercised at all times while performing CRISPR editing if it is deemed ethical in the first place.
All things considered, new possibilities of CRISPR technology continue to be realized on a daily basis. With its profound impact in changing the tide of the pandemic along with curing once “incurable” diseases, time will only tell what CRISPR has in store for us.
References:
1. Fernández, C. R. (2019, July 23). Seven Diseases that Crispr Technology could Cure. Labiotech.Eu. https://www.labiotech.eu/bestbiotech/crispr-technology-cure-disease/
2. What are Genome Editing and Crispr-cas9? : Medlineplus genetics. (n.d.). Retrieved April 5, 2021, from https://medlineplus.gov/genetics/understanding/genomicresear ch/genome editing/
3. Melão, A. (n.d.). Crispr-cas9 to Treat Huntington’s and other Diseases More Likely if Tiny Lipids are Delivery Vehicle, study says. Retrieved April 5, 2021, from https://huntingtonsdiseasenews.com/2019/08 /27/lipid-nanoparticles-as-delivery-vehicle-may-aid-crispr-cas9- gene-editing-tool/
4. S, R., Sanders, March 30, M. relations, 2021April 2, & 2021. (2021, March 30). FDA Approves First Test of CRISPR to Correct Genetic Defect Causing Sickle Cell Disease. Berkeley News. https://news.berkeley.edu/2021/03/30/fda-approves-first-test-ofcrispr -to-correc t-genetic-defect-causing-sickle-cell-disease/
5. Hastings, Colin. (2021, March 31). Quick and Easy Crispr-Based Covid test. Medgadget. https://www.medgadget.com/2021/03/quick-andeasy-crispr-covid-test-spots-mutations.html
6. Popescu, Adam. (2019, April 18). CRISPR-Edited “Super Plants” Might be our Best Chance to Slow Climate Change. Genetic Literacy Project. https://geneticliteracyproject.org/2019/04/18/crispr-edited-superplants-might-be-our-best-chance-to-slow-climate-change/
7. Bergman, Mary Todd. (2019, January 9). Harvard Researchers Share Views on Future, Ethics of Gene Editing. Harvard Gazette. https://news.harvard.edu/gazette/stor y/2019/01/perspectives-ongene-editing/
Comments