TEDMED 2015: A brief history of CRISPR and what's next

Print 23 November 2015
Stacy Lawrence / Fierce Medical Devices

Only a scant few years old, CRISPR gene editing technology already is heavily weighted with potential implications for human disease and health. It's already being used to more easily and precisely create genetically modified plants and animals. And for the first time last year, CRISPR was used to genetically modify a human embryo.

What's expected to follow is an avalanche of innovation that could lead to CRISPR-repaired stem cells that are edited in the laboratory and then returned to the body to proliferate corrected cells. Already, researchers are editing cells with mutations associated with various genetic disorders including cystic fibrosis, muscular dystrophy and Huntington's disease. Even researchers of contagious but incurable diseases such as HIV/AIDs are working to use gene editing to repair cells involved in blood production.

Ultimately, CRISPR gene editing could correct for genetic disorders at the germ line level--enabling heritable genetic changes. Which, of course, raises complex ethical issues of how CRISPR technology will be used and regulated.

Sam Sternberg

Sam Sternberg, a recent doctoral researcher in the Doudna Lab at UC Berkeley, held a TEDMED audience in Palm Springs, CA, enraptured unfolding these tales of how the CRISPR-Cas9 technology that he helped contribute to could be applied to human health.

Five years ago, CRISPR was virtually unheard of even among scientists.

Its origins lie in observations by Japanese scientists that the same 28 sequence of letters repeat multiple times in the DNA of theEscherichia coli bacteria, Sternberg said. By 2000, this phenomenon was found to be repeated in more than half of bacteria. The changes were eventually found to be made via bacteriophages, viruses that attack bacteria that outnumber them by 10 to one. The surviving bacteria integrate DNA fragments from an attacking virus to prevent future reinfection--Sternberg offers the analogy of the corner store owner who posts pictures of past thieves in order to deny them entrance in the future.

The CRISPR technology takes this mechanism and applies it to enable precise cuts of DNA, with the removal of one clearly defined portion of the sequence to be replaced by another, corrected one. In fact, Sternberg said the CRISPR has made it much easier to precisely edit DNA than researchers ever anticipated.

Astonishingly, he likens how CRISPR works to the "find and replace" feature in Microsoft Word--in which the offending sequence is efficiently identified throughout the genome and then simply replaced wherever it occurs.

This is already reconfiguring the way genetically modified animals, fruits and vegetables are being designed for human consumption--making it fast, easy and cheap to genetically modify them for desired genetic traits to accommodate consumer tastes or researcher's needs. For anti-GMO activists, the proliferation of CRISPR-based genomic tweaking is likely to prove overwhelming.

Some of the commercial applications include making Streptococcus thermophiles, a bacteria commonly used in cheese and yogurt production, more virus-resistant. He said that if you've eaten a yogurt in the last year, you've already been consuming these heartier, CRISPR-tweaked bacteria.

But for human applications, CRISPR opens an entire Pandora's box of questions--including who will profit from the new technology and where the line is between disease prevention and genetic enhancement. Already, there's been almost $1 billion invested in startups based on the CRISPR technology, Sternberg said.

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