New technique to detect gene doping in human plasma

All athletes wish to be at the top of their game while competing, yet some turn to corrupt strategies to achieve peak speed, agility, and muscle growth. The latest advancements in gene-editing technology could lure athletes to change their DNA to gain an upper hand.

A new study takes steps toward detecting CRISPR/Cas gene doping in athletes. Image Credit: Marino Bocelli/Shutterstock.com

A new study conducted by researchers shows the first steps in the detection of this type of doping both in human plasma and in live mice. The study was published in the Analytical Chemistry journal from the American Chemical Society.

Generally, scientists use a gene-editing method known as CRISPR/Cas to precisely modify the DNA in various organisms. This method recently garnered wider attention when the main developers of the approach were awarded the 2020 Nobel Prize in Chemistry. Scientists could use this method to add an RNA molecule and a protein into cells.

The RNA molecule leads the protein to the suitable DNA sequence, following which the protein cuts DNA—similar to a pair of scissors—to enable modifications. Although there have been ethical concerns raised about the method’s potential application in humans, a few athletes could ignore the risks and misuse it to modify their genes.

Since CRISPR/Cas modifies the DNA, it is coined as “gene doping” and banned by the World Anti-Doping Agency, an independent international organization. However, a proficient technique must be developed to detect CRISPR/Cas gene editing.

Therefore, Mario Thevis and collaborators intended to see whether they could find the protein that would most probably be used in this type of doping—Cas9 from the Streptococcus pyogenes (SpCas9) bacteria, in mouse models and human plasma samples.

The SpCas9 protein was spiked into human plasma. Then, the protein was isolated and cut into pieces. Investigation of the pieces through mass spectrometry revealed that it was feasible to effectively identify rare components of the SpCas9 protein from the complex plasma matrix.

As part of the other approach, inactivated SpCas9—with the ability to regulate gene expression without modifying the DNA, was spiked into human plasma samples. With a slight alteration, the approach enabled the team to purify and find the inactive form.

Lastly, the mice were injected with SpCas9 and proved that their concentrations peaked in circulating blood after 2 hours and could be spotted up to 8 hours after injection into muscle tissue. According to the team, although more studies are needed, this is the preliminary step toward a test to identify athletes trying to gain a biased upper hand.