Whether they’re trekking 1,450 kilometers (900 miles) or discovering new viruses, cats are pretty great. Unless, of course, you’re allergic. But what if there was a way to create felines that don’t leave your throat feeling akin to sandpaper? It’s early days, but new research into the protein that triggers allergies to cats has hinted at a potential gene editing target that could eventually give us hypoallergenic cats.
Approximately 15 percent of the US population is allergic to cats, experiencing symptoms including coughing, sneezing, irritated eyes, and asthma, which can range from mild to severe. Around 500,000 asthma attacks per year and 350,000 emergency care visits have been attributed to cat allergic disease, and yet, little is known about the diversity of the allergen that causes it or how it evolved.
There are several cat proteins known to induce an allergic response, the major one being Fel d 1, which is produced by all cats regardless of their breed, hair length, sex, age, or body weight. Cats produce Fel d 1 in their sebaceous, salivary, perianal, and lachrymal glands – contrary to common belief it is not the hair itself that causes allergies, but Fel d 1 on the hair. Different cats will produce different levels of the protein, meaning that some are more allergenic than others. However, as things stand, there are no cats that are completely hypoallergenic.
Fel d 1 is formed of two chains, and there are two genes, called CH1 and CH2, which encode each chain respectively. Its biological function is currently unknown, but research into similar proteins in other mammals suggests the allergen may be involved in immune regulation, protection of the epithelium, or chemical communication among cats.
In the new study, researchers compared Fel d1 sequences among 276 exotic and domestic cat species across millions of years of evolution, finding that they were variable along each evolutionary lineage. In fact, the team identified over 100 unique mutations in the protein sequence and found that CH1 and CH2 genes are also highly variable, which suggests the function of Fel d 1 could vary among cat species, or that Fel d 1 may not be essential for cats.
This was bolstered by the discovery that two cats – a cougar and a black-footed cat from Southern Africa – had natural mutations that significantly impair Fel d 1 protein. There has also been recent evidence of healthy cats with CRISPR-edited CH2.
So what does all this have to do with hypoallergenic cats? If our feline friends can do without Fel d 1, then we may be able to engineer happy, healthy cats without it – cats that, consequently, won’t get our noses running.
“The results suggest that Fel d 1 is a viable target for gene deletion to develop Fel d 1-free cats,” the researchers explain. “Deleting or rendering the Fel d 1 genes nonfunctional could have therapeutic implications for cat allergy sufferers by removing the allergen from the source.”
Essentially, with a little bit of CRISPR tinkering to delete CH1 and CH2, you could create hypoallergenic cats.
Of course, we’re still a long way from seeing this come to fruition, but it’s a very promising avenue of research, especially for any unfortunate cat lovers plagued by allergies to their beloved pets.
The study is published in PNAS Nexus.
Source Link: Hypoallergenic Cats Could Be On The Horizon Thanks To New Genetic Discovery
