Do you want bigger muscles? Want to make those brown eyes
blue? Does your memory resemble a slice of Swiss cheese? Well, step right up
and let me tell you about biohacking! Lend me your ears…and I’ll tell you how
to improve them! With our new do-it-yourself genetic engineering kits, you can
change whatever genes you want!
Bio-savvy entrepreneurs are determined to make biohacking a
mainstream activity. Companies
are emerging that promote DIY gene therapy, so now anyone with an opposable
thumb can pipet DNA changes into their bodies, their pesky little sister, pets,
or just about any living creature they encounter.
Wouldn’t you like to be a biohacker too? Or is biohacking just the latest incarnation of snake oil? |
Those products seem benign compared to Zayner’s ultimate
objective: selling genetic engineering tools to the masses so they can modify
their own genes, or those of other living creatures, in whatever way they want
without any oversight or regulatory approval. Zayner has already initiated
experiments on himself and encourages others to join him on this wild ride. In
the rambling presentation below, Zayner explains over shots of scotch and F-bombs
that he wants to crowdsource genetic engineering because he believes it will
facilitate innovation. Why let professional scientists have all the fun? Zayner
demonstrated how easy biohacking your genome can be by injecting the reagents
into his arm during the presentation and distributing free samples for the
audience to take home.
Let’s take a closer look at his idea. Zayner is using CRISPR/Cas9,
a powerful new tool for gene editing, to disable his myostatin gene (learn about
the basics
of CRISPR/Cas9 and its application
in gene therapy). Cas9 is a DNA-cutting enzyme that is directed to a
specific site in DNA by a guide sequence. Myostatin stops muscles from growing,
so his plan is to knockout this gene in his muscle cells in hopes that it will
make them grow once again. Given his affinity for scotch, a more useful
experiment might have been to enhance his alcohol dehydrogenase genes.
There is evidence linking the depletion of myostatin to
muscle growth. Mice
engineered to lack myostatin have double their normal skeletal muscle mass.
CRISPR/Cas9 has been specifically used to knockout myostatin in animal embryos,
such as rabbits, and the
genetically modified animals grew to have more muscle mass. Moreover, when
humans are born with mutations that lead to less functional myostatin, they
also have more muscle mass (or, in less pleasant-sounding medical terms, “gross muscle
hypertrophy”).
CRISPR has already been used to successfully modify human
embryos (none were implanted), but to date, no one has tried CRISPR/Cas9 in a
living adult. Zayner’s strategy is to simply inject plasmid DNA that contains the
Cas9 gene along with the guide sequence that directs it to the myostatin gene.
Importantly, he’s produced no evidence yet to show that these reagents work in human cells. Ideally, we’d like to see confirmation of the gene modification in a muscle biopsy from Zayner, or proof that his approach works in an adult animal model. At the very least, it would be useful to know whether his system alters the gene in cultured cells.
Importantly, he’s produced no evidence yet to show that these reagents work in human cells. Ideally, we’d like to see confirmation of the gene modification in a muscle biopsy from Zayner, or proof that his approach works in an adult animal model. At the very least, it would be useful to know whether his system alters the gene in cultured cells.
So, can this really work? There are some formidable
obstacles and shortcomings. First, the injected plasmid DNA has to get into the
muscle cells. Many would argue that the DNA is likely to be degraded or damaged
along the way. There is scarce evidence that intramuscular injection of DNA
works, but I did find one
study done in mice from 1993 suggesting it is possible, although expression
levels of the gene injected in this mouse study varied. Variations in the
levels of Cas9 or the guide sequence would certainly affect the outcome.
Nevertheless, let’s pretend some of it gets into a few muscle cells and they make the Cas9 protein and its guide sequence. The next big assumption we have to make is that the guide sequence used actually cuts the myostatin gene. Multiple guide sequences usually have to be tried to find one that works and, as mentioned above, I’ve seen no evidence that this particular guide sequence operates as it should in human cells.
Additionally, you have two copies (alleles) of myostatin,
one from mom and one from dad. To knockout myostatin completely, Cas9 would
have to cut both alleles. Let’s assume we get that far and both alleles of
myostatin are cut. Sometimes cells can repair the DNA cut without incident. For
myostatin to be disabled, the cell would have to make a mistake when repairing
the severed DNA (which they do, but not all the time). Assuming we jump all
these hurdles, that one cell or handful of cells is not likely to produce any
noticeable change in muscle mass, especially if only one allele was disabled.
Zayner claims repeated injections might overcome this issue, but given the
sheer number of cells that would need to be altered to produce a visible
effect, the claim seems to be on very shaky ground.
Despite all the caveats, disrupting a gene is actually the
easiest application of CRISPR/Cas9. To add or change a genetic sequence, an
additional fragment of DNA needs to be incorporated where Cas9 made the incision.
And if you wanted to use CRISPR/Cas9 to give yourself wings or eyes in the back
of your head, you can forget about that. We are nowhere close to knowing how to
do such things.
More alarming, there is risk of dangerous side-effects. While the loss of myostatin will increase muscle size as well as bone mineral density and bone mass, it also leads to spinal disc degeneration and spinal osteoarthritis. Second, there is a risk of infection or an allergic reaction to the injections. Third, CRISPR/Cas9 has been reported to produce so-called “off-target” effects. In other words, the guide sequence sometimes escorts Cas9 to other places in the genome, where it may introduce cuts in genes that were not intended to be destroyed—a genetic equivalent of friendly fire.
There’s also the possibility that the CRISPR/Cas9 plasmid itself
could integrate into the genome, again possibly disrupting critical genes. One study showed that DNA
injected into mouse muscles persisted for life, cranking out the protein
constantly. What would happen if Cas9 continues to be produced in Zayner’s
cells for the rest of his life? In the worst-case scenario, it would continue
to cut up his DNA indiscriminately. There’s also a study in mice suggesting
that DNA injection can
accelerate autoimmune responses. Finally, unlike injecting an embryo in
which all cells have a high probability of being modified, Zayner’s approach is
going to produce mosaic effects. In other words, some cells will be edited, but
others will not, which could result in a disfigured arm. Zayner dismisses all of these risks with disquieting nonchalance.
If you don’t want to risk modifying your genome to kill your myostatin gene, you can always buy inflatable muscles to wear under your shirt. |
There’s no product currently available from The ODIN that could bring on the apocalypse, but it is the principle that concerns many people, scientists and non-scientists alike. Even the most avid science enthusiasts are likely to take issue with providing potential crackpots the tools to screw with the recipe of life. Genetic engineering is exciting and promising, but must be explored with great caution by well-trained professionals following reasonable regulations because there is no way to unscramble this egg.
Biohacking has been banned in several countries, and on November 21, 2017 the FDA updated their web site to state that self-administration of gene therapy is against the law. It seems that Zayner, a self-professed fan of the TV show Survivor, just had his torch snuffed out by government regulators chanting, “The tribe has spoken.” |
Contributed by: Bill
Sullivan
Follow Bill on
Twitter.
The author thanks Colin Sullivan for research assistance and helpful discussions, and Jason Organ for editing and helpful suggestions.
The author thanks Colin Sullivan for research assistance and helpful discussions, and Jason Organ for editing and helpful suggestions.
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