Will CRISPR-Cas9 Help Biohacker to Be Next Captain America

In the marvel universe, a short and thin guy named Rogers underwent a series of gene transformations and became Captain America, one of the most popular heroes protecting the world peace with his extremely strong and unconquerable figure. This may be absurd for most people, but some biological hackers have been devoted to this dream of power and strength.

36-year-old Josiah Zayner was a NASA biologist. In order to gain more muscle, he became the first person to genetically transform himself with the genetic editing tool CRISPR-Cas9. However, he did not complete the test at the hospital or the university laboratory, but at a biotech conference with this stunt live-streamed.

Does it really work? Theoretically, yes.

Past studies have suggested that the Myostatin (MSTN) gene is highly expressed in the skeletal muscle of the animal's body and is an important gene for negative regulation of muscle growth. Many scientific researches have shown that a lack of myostatin function results in the excessive growth of skeletal muscle, demonstrating the existence of a powerful mechanism to control muscle size in normal individuals.

But how to deal with the MSTN gene? Clustered regularly interspaced palindromic repeats -associated protein 9 (CRISPR-Cas9), a revolutionary tool, serves as a cutting-edge technology to edit parts of the genome.

First of all, a number of plasmids are connected with the Cas9 gene sequence (for the transcription and translation of Cas9 nuclease), and a pre-designed sequence (for the transcription of gRNA) including a guide sequence for the recognition of MSTN gene, a sequence for the formation of unique RNA secondary structure, and a promoter sequence that initiates transcription in muscle cells.

Then, after intravenous injection, these plasmids pass through the blood to cells throughout the body. Only in the muscle cells can gRNA and Cas9 be efficiently transcribed due to the presence of specific promoter sequences in the plasmid, while hardly affecting the non-muscle cells.

In muscle cells, guided by the gRNA, the Cas9 protein locates to and cleaves the MSTN gene, resulting in the formation of a DNA double strand break (DSB). As one of the DSB self-repair pathways of somatic cells, non-homologous end joining (NHEJ) pathway links the two ends of the broken DNA efficiently and introduces insertion or deletion of different lengths. These mutations will lead to translation of non-functional MSTN protein, which lacks (even loses) inhibition of muscle growth, and finally promoting muscle growth.

In this case, Zayner injected circular plasmids harboring the MSTN-targeting CRISPR machinery into his veins hoping to delivery some of the DNA into his muscle cells, but as he admitted on his blog, this couldn’t modify enough cells to make any discernible difference.

As a milestone of biotechnology, CRISPR-Cas9 can be widely used not only in medical treatment, but also in the food and agricultural industries. However, the use of CRISPR-Cas9 can be dangerous. Off-target activity is the main concern here. A single gene edit could cause unintended activity somewhere else in the genome. A possible consequence of this is abnormal growth of tissues, leading to cancer.

"I’ll admit when I did it, it was very provocative - kind of on purpose, kind of on accident…. There’s no doubt in my mind that somebody is going to end up hurt eventually." Said Zayner who is now under investigation of the California Department of Consumer Affairs (DCA) for unlicensed practice of medicine. "CRISPR Cas9 is becoming available to the public, which might result in negative consequences outside professional labs", says a senior scientists of Creative Biolabs, a company devoted to gene therapy development services, "when offering our CRISPR/Cas system services, we always stress that they are for lab research use, not for human therapeutic use."

In fact, January 2020 will witness the first-ever bill regulating genome editing technology in California, which means CRISPR kits are no longer permitted to use for self-administration. How effective regulation of biohacking remains to be seen as these technologies become increasingly commoditized and easily accessible. But until humans better understand the secret of DNA and the potential pitfalls of fiddling with it, regulations aimed at DIY gene editing probably aren’t a bad idea.

Gene editing is just like pandora’s box, and the DIY work of transforming an individual into a superhero in one’s garage or kitchen should be strictly regulated in case someone created a Frankenstein instead of Captain America.

Candy Swift: Focus on the cutting edge biological information around the world.