By Kyla Hughes
In a perfect world, humans would be free of diseases, illnesses, syndromes, and other conditions. Unfortunately, many people worldwide face some form of illness varying from manageable to debilitating (GBDS Collaborators, 2015). One specific, prevalent condition is Immunoglobulin E (IgE)-meditated food allergy, commonly referred to as “food allergies.” IgE food allergies have increased in prevalence in the United States and across the world in recent years. Approximately 1 in 10 adults and 1 in 12 children in the United States suffer from food allergies from at least one of eight major food allergens: soy, wheat, dairy, eggs, fish, shellfish, peanuts, and tree nuts (Gupta et al., 2019).
For people who have food allergies, avoiding certain foods can be troublesome. In some cases, even after avoiding them, an accidental interaction with a specific allergen can lead to illness, hospitalization, or even death (Warren et al., 2020). Having a food allergy can also be a financial burden; from annual visits with allergists to buying allergen-free food products to purchasing expensive, prescribed Epinephrine. For these reasons, and many more, allergists and scientists are conducting research to identify if the burden of IgE food allergies can be relieved for those who suffer from them day-to-day.
Image Source: Flickr USDA gov https://www.flickr.com/photos/usdagov/27239936717
One important question scientists have begun to ask themselves is:
Can food allergens be genetically removed from major food crops using CRISPR engineering?
Certainly!
In recent decades, CRISPR (Clustered Regularly Interspaced Short Palindromic Sequences) editing has shown promising results in agricultural, medical, and other related fields. This past year, the Unite States Food and Drug Administration approved the first gene therapy to treat sickle cell disease (SCD); this therapy utilizes CRISPR technology (FDA, 2023). In the agriculture sector, CRISPR has the potential to improve crop yields, reduce the need for pesticides, herbicides, and fertilizers, and promote plant growth in the face of climate change.
On the molecular level, CRISPR can be complex, however, learning the fundamentals will certainly be useful even for non-scientists. When discussing IgE food allergies, CRISPR serves as a precise engineering tool to completely delete genes relating to allergy. Using a
Cas-protein (Cas9) nuclease, guide RNA (gRNA), and a defined 20 nucleotide site, CRISPR can induce specific cuts, or cleaves, within a DNA sequence.
Infographic created by Daniel Alique García on https://plantae.org/crispr-vs-allergens/
Soybean—a major food crop in the United States—is known to be one of eight major allergens. Two proteins found within soybean are key contributors to allergens in humans: glycoprotein Gly m Bd 29 K and protein Gly m Bd 30 K (Sugano et al., 2020). To knock out genes encoding these two proteins, researchers utilized CRISPR-Cas9 systems along with Agrobacterium-mediated transformation. This gene knockout subsequently reduced protein expression in transgenic soybean plants when compared to original, wildtype soybean, proving initial success for future food allergy-related endeavors (Sugano et al., 2020).
A study with peanuts and the Ara h 2 glycoprotein utilized a technology similar to CRISPR (RNA interference, or RNAi) to induce a knock-down gene expression of this glycoprotein which plays a role in peanut allergenicity (Dodo et al., 2007). The RNAi plasmid was then delivered to peanut plants and integrated into the plant’s genome. A 25% decrease in Ara h 2 glycoprotein was observed in seeds from transgenic plants compared to the original peanut. This means that the new, transgenic plant is not completely rid of the peanut allergen, but the reduction of Ara h 2 is certainly a research advancement.
There is still major research that must be conducted to fully eliminate IgE food allergens from food crops. However, this research is a fundamental step in the right direction and will hopefully give people an allergy-free future!
References
Dodo, H. W., Konan, K. N., Chen, F. C., Egnin, M., & Viquez, O. M. (2008). Alleviating peanut allergy using genetic engineering: the silencing of the immunodominant allergen Ara h 2 leads to its significant reduction and a decrease in peanut allergenicity. Plant biotechnology journal, 6(2), 135-145.
FDA (2023, December 08). FDA Approves First Gene Therapies to Treat Patients with Sickle
Cell Disease
Vos, T., Barber, R. M., Bell, B., Bertozzi-Villa, A., Biryukov, S., Bolliger, I., ... & Brugha, T. S. (2015). Global, regional, and national incidence, prevalence, and years lived with disability for 301 acute and chronic diseases and injuries in 188 countries, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013. The lancet, 386(9995), 743-800.
Gupta, R. S., Warren, C. M., Smith, B. M., Jiang, J., Blumenstock, J. A., Davis, M. M., ... & Nadeau, K. C. (2019). Prevalence and severity of food allergies among US adults. JAMA network open, 2(1), e185630-e185630.
Sugano, S., Hirose, A., Kanazashi, Y., Adachi, K., Hibara, M., Itoh, T., ... & Yamada, T. (2020). Simultaneous induction of mutant alleles of two allergenic genes in soybean by using site-directed mutagenesis. BMC Plant Biology, 20, 1-15.
Kyla Danae Hughes is a rising Sophomore within the College of Agriculture at Tennessee State University. Kyla is a farm bill scholar and a Dean's scholar involved in research projects on CRISPR-cas use in the legume Medicago truncatula. Kyla loves spending time outdoors, hiking and backpacking. She is also an accomplished violinist with a passion for baking desserts!
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