The Promise of CRISPR in Allergy Management

In the ongoing quest to create the first genuinely allergy-free cat, a breakthrough is on the horizon. One innovative company is exploring a DNA-modifying injection aimed at helping pet owners who suffer from allergies.

Reengineering Life is a series by OneZero that examines the remarkable ways genetic technology is transforming both humanity and the environment.

For the 10% of individuals allergic to cats, the culprit is a protein found in cat saliva and skin. This troublesome protein, known as Fel d 1, spreads when cats groom themselves and release hair and dander throughout their living spaces.

Researchers have been investigating Fel d 1 for decades due to its significant role in triggering cat allergies. If a method could be devised to prevent cats from producing this protein, it might put an end to the incessant sneezing, coughing, and sniffling that plague allergy sufferers. Presently, allergy sufferers face limited options: certain breeds labeled as "hypoallergenic" still produce allergens, and allergy shots often lack effectiveness for many.

With the advent of CRISPR, new avenues are being explored for creating hypoallergenic cats. Scientists at Indoor Biotechnologies, located in Virginia, have successfully employed CRISPR technology to eliminate the gene responsible for producing Fel d 1. Importantly, the team conducted their experiments on feline cells rather than live animals, indicating that this method holds promise for actual pets.

“We’ve been speculating on the impact of removing the gene from cats,” explains Martin Chapman, CEO of Indoor Biotechnologies and a former professor of medicine and microbiology at the University of Virginia. “Our ultimate goal is to genetically modify cats so they no longer produce Fel d 1.”

Hypoallergenic cats have been a point of interest before. Back in the mid-2000s, biotech company Allerca claimed to offer hypoallergenic cats bred to produce reduced levels of Fel d 1. However, a 2013 report from ABC News revealed that these cats, priced between $4,000 and $28,000, exhibited similar levels of the protein as standard cats. One purchaser shared that her children were still highly allergic to these cats, forcing her to find them new homes.

In contrast to Allerca, Indoor Biotechnologies aims not to breed new genetically altered cats but to create a CRISPR-based treatment for existing ones. If deemed safe, this drug would allow pet owners to take their cats to a veterinarian for a simple injection, resulting in cats that do not trigger allergies.

To facilitate their CRISPR studies, Indoor Biotechnologies collaborated with a local branch of the Society for the Prevention of Cruelty to Animals to obtain tissue samples from 50 cats. Nicole Brackett, a postdoctoral scientist at the company, extracted DNA from these samples, isolating and sequencing the Fel d 1 gene in each. Her goal was to identify common genetic sequences that could be targeted by CRISPR, as the drug must affect a sequence present in most cats.

Focusing on a specific genetic sequence, Brackett designed a CRISPR system targeting it. CRISPR comprises two elements: a cutting protein and a guide molecule, which can be programmed to locate any segment of the genome. Upon reaching the target, the cutting protein performs its function, excising the specified genetic sequence.

This research marks an initial step toward a CRISPR-based treatment for cats, with Indoor Biotechnologies having filed a patent for this approach. The next phase involves editing the gene in cat tissues in a lab setting to ascertain whether it ceases to produce the allergy-inducing protein.

While initial findings are encouraging, there remains the possibility that Fel d 1 serves a vital role beyond allergen production, and its removal could have adverse effects on the cats. Chapman and Brackett acknowledge this concern, suggesting that actual experiments on cats will be necessary to explore potential outcomes. One proposed method involves deleting the protein-producing gene in cat embryos and transferring them into a female cat’s womb to observe any health issues in the resulting kittens.

Other researchers are pursuing alternative, less invasive methods. For instance, scientists at Nestlé Purina PetCare have developed a cat food containing a naturally occurring egg protein that they assert can lower Fel d 1 levels in saliva, though it does not eliminate the allergen entirely.

If CRISPR proves effective without significant side effects for our feline companions, it could potentially eradicate most cat allergies. However, for those allergic to cats, it may be wise to hold off on getting a pet for now, as a CRISPR solution is likely still a few years away.

The video titled "The Major Cat Allergen, Fel d 1, Is a Viable Target for CRISPR Gene Editing" delves deeper into the implications of targeting this protein through genetic editing, offering insights into the potential for allergy relief for cat lovers.

More stories from OneZero about the future of genetic engineering:

A Shot of CRISPR Could Restore Sight to the Blind

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CRISPR Eliminated Symptoms of Genetic Disease in Two Patients

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In U.S. First, Scientists Safely Edit Cancer Patients’ Cells with CRISPR

The pioneering study is backed by tech billionaire Sean Parker.