April 9, 2013: British cosmologist Stephen Hawking, who has motor neuron disease, gives a talk titled "A Brief History of Mine," to workers at Cedars-Sinai Medical Center in Los Angeles. (AP Photo/Cedars-Sinai, Eric Reed)
Just a few weeks ago, we marveled at the first instance of human embryo editing with CRISPR in the United States. Now, the gene editing technique has been used for yet another impressive purpose. Scientists at the University of California San Diego believe that a modified version of the CRISPR/Cas9 tool could be used to track RNA in live cells using a method known as RNA-targeting Cas9. But more importantly, this methodology could allow doctors to fix molecular mistakes that result in diseases like myotonic dystrophy types 1 and 2, which are the most common form of hereditary ALS and Huntington's disease.
These types of diseases occur when errors in RNA sequences prevent the production of key proteins. However, with RNA-targeting Cas9, researchers were able to get rid of the RNA errors, particularly those linked to ALS and Huntington's. In fact, so effective was this new methodology that scientists were able to remove more than 95 percent of the problematic RNA.
This is exciting because were not only targeting the root cause of diseases for which there are no current therapies to delay progression, but weve re-engineered the CRISPR-Cas9 system in a way thats feasible to deliver it to specific tissues via a viral vector, saidsenior author Gene Yeo, professor of cellular and molecular medicine at the UC San Diego School of Medicine.
Yeo's team also found that applying RNA-targeting Cas9 managed to reverse 93 percent of dysfunctional RNA targets in muscle cells, ultimately turning those cells back into what appeared to be healthy control cells. But while these are all promising results, for the time being, the technique has only been tested in lab settings.
The main thing we dont know yet is whether or not the viral vectors that deliver RCas9 to cells would illicit an immune response, Yeo said. Before this could be tested in humans, we would need to test it in animal models, determine potential toxicities and evaluate long-term exposure.
Still, the new methodologies could be groundbreaking in the medicine field.
As David Nelles, co-first author of the study said,We are really excited about this work because we not only defined a new potential therapeutic mechanism for CRISPR-Cas9, we demonstrated how it could be used to treat an entire class of conditions for which there are no successful treatment options.
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