Monthly Archives: August 2017

Hospitals & Health Networks

Genomic Medicine Has Entered the Building Hospitals & Health Networks In July, the group published a report in the New England Journal of Medicine describing a variant of the gene ANGPTL3 associated with a reduced risk of cardiovascular disease detected in some MyCode participants. The gene variant codes for a protein ...

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Genomic Medicine Has Entered the Building - Hospitals & Health Networks

In BriefResearchers from UC San Diego's School of Medicine have testeda modified CRISPR-Cas9 technique designed to target RNA instead ofDNA. Rcas9 could potentially improve the lives of patients withALS, Huntington's disease, or myotonic dystrophy by delaying theprogression of their disorders. Editing RNA

The most efficient and effective gene-editing tool in use today is CRISPR-Cas9. Just this year, researchers have successfully used it fora wide variety of experiments, from modifying garden vegetables to encoding a GIF in bacterial DNA. Most recently, the tool was used to remove a genetic disease from a human embryo.

Although undeniably powerful, CRISPR-Cas9 does have its limitations; it can only target DNA. To extend its capabilities to includeRNA editing, researchers from the University of California San Diego (UCSD) School of Medicinedeveloped amodification of CRISPR, and theyre calling their toolRNA-targeting Cas9 (RCas9).

In a study published in Cell, the UCSD team tested their technique by correcting the kinds of molecular mistakes that cause people to develop microsatellite repeat expansion diseases, such ashereditary amyotrophic lateral sclerosis (ALS)and Huntingtons disease.

During standard CRISPR-CAs9 gene editing, a guide RNA is instructed to deliver a Cas9 enzyme to a specific DNA molecule. The researchers from UCSD instead instructed it to target an RNA molecule.

Tests conducted in the laboratory showed that RCas9 removed 95 percent ofproblem-causing RNA for myotonic dystrophy types 1 and 2, Huntingtons disease, and one type of ALS. The technique also reversed 93 percent of the dysfunctional RNA targets in the muscle cells of patients with myotonic dystrophy type 1, resulting in healthier cells.

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, senior author Gene Yeo, a cellular and molecular medicine professor at UCSD School of Medicine, explained in a press release.

Across the globe, an estimated 450,000 patients are said to be living with ALS. Roughly 30,000 of those are from the U.S. where 5,600 people are diagnosed with the diseases every year. The exact number of Huntingtons disease cases, however, isnt quite as easy to pin down. One estimate says that around 30,000 Americans display symptoms of it, while more than 200,000 are at risk.

Regardless of the exact numbers, these two neurological diseases clearly affect a significant number of people. This prevalence and the absence of a known curemakes the UCSD teams research all the more relevant. Even more exciting is the fact that the same kinds of RNA mutations targeted by this study are known to cause more than 20 other genetic diseases.

Our ability to program the RCas9 system to target different repeats, combined with low risk of off-target effects, is its major strength, co-first author of the study Ranjan Batra said in the UCSD press release.

However, the researchers do know that what theyve accomplished is just a first step. While RCas9 works in a lab, they still have to figure out how it will fare when tested in actual patients.

The main thing we dont know yet is whether or not the viral vectors that deliver RCas9 to cells would elicit an immune response, explained Yeo. Before this could be tested in humans, we would need to test it in animal models, determine potential toxicities, and evaluate long-term exposure.

Ultimately, while RCas9 couldnt exactly deliver a cure, it could potentially extend patients healthy years. For disease like ALS and Huntingtons, thats a good place to start.

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A New Gene Editing Technique Could Finally Allow Us to Treat ALS - Futurism

By KIMBERLY HOUGHTON Union Leader Correspondent August 14. 2017 11:06PM

This sequence of images shows the development of embryos after being injected with a biological kit to edit their DNA, removing a genetic mutation known to cause hypertrophic cardiomyopathy.(Oregon Health & Science University)

Bryan Luikart, an associate professor of molecular and systems biology at Geisel School of Medicine at Dartmouth College.

It is pretty amazing. It is a super-exciting time to be a scientist right now, said Bryan Luikart, an associate professor of molecular and systems biology at Geisel School of Medicine at Dartmouth College.

The study, which was published in the journal Nature, was detailed in a New York Times report. According to the article, Oregon researchers reported they repaired dozens of human embryos, fixing a mutation that causes a common heart condition that can lead to sudden death later in life.

The way they have dodged some ethical considerations is that they didnt go on to have that embryo grow into a person, said Luikart, explaining that if the embryos with the repaired mutation did have the opportunity to develop, they would be free of the heart condition.

At the Geisel School of Medicine at Dartmouth, Luikart and his colleagues have already been using this concept with mouse embryos, focusing specifically on autism.

Researchers are using the gene-editing method called CRISPR-Cas9 in hopes of trying to more fully understand autism, which he said is the most critical step in eventually finding a cure.

I think the CRISPR is a tremendous breakthrough. The question really is where and when do you want to use it, Luikart said. I have no ethical concerns using it as a tool to better understand biology.

The new milestone, an example of human genetic engineering, does carry ethical concerns that Luikart said will trigger some debates. He acknowledged that while the advancement of gene-editing technology could eventually stop unwanted hereditary conditions, it also allows for creating babies with smarter, stronger or more attractive traits.

The ability to do that is now within our grasp more than it has ever been, he said.

More importantly, the breakthrough could ultimately eliminate diseases, Luikart said. As the technology advances, he said, genetic diseases that are passed down to children may be corrected before the child receives them.

He used another example of a brain tumor, which often returns after it is surgically removed. Now, once the brain tumor is removed, there is the possibility of placing something in the space to edit and fix the mutation that causes the brain tumor in the first place if physicians are able to find the right cell to edit, Luikart said.

People are definitely thinking along those lines, or cutting the HIV genome, said Luikart, who predicts that those advancements will occur in mice within the next decade, and the ability to do that in humans is definitely there.

The big question is whether that can occur without some sort of side effect that was not predicted, he said.

Columbia University Medical Center posted an article earlier this year warning that CRISPR gene editing can cause hundreds of unintended mutations, based on a study published recently in Nature Methods.

This past May, MilliporeSigma announced it has developed a new genome editing tool that makes CRISPR more efficient, flexible and specific, giving researchers more experimental options and faster results that can accelerate drug development and access to new therapies, according to a release.

CRISPR genome editing technology is advancing treatment options for some of the toughest medical conditions faced today, including chronic illnesses and cancers for which there are limited or no treatment options, states the release, adding the applications of CRISPR are far ranging from identifying genes associated with cancer to reversing mutations that cause blindness.

It is pretty big news, Luikart said.

khoughton@newstote.com

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New Hampshire biologist reacts to gene-editing discovery - The Union Leader

Researchers have found a way to break down aggregated RNA molecules that cause diseases such as certain inherited forms of amyotrophic lateral sclerosis (ALS).

As the technique has the potential to treat several diseases which currently lack treatment options, the research team from theUniversity of California, San Diego (UCSD) made sure to engineer the new system so that it could be delivered to specific tissues with non-infectious viruses.

The method builds on a well-known gene-editing system, called CRISPRCas9, but was adapted to target RNA instead of DNA. The new method is called RNA-targeting Cas9, or simply, RCas9.

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, the studys senior author, Gene Yeo, said in a press release. He is aprofessor of cellular and molecular medicine at UCSD School of Medicine.

The study, Elimination of Toxic Microsatellite Repeat Expansion RNA by RNA-Targeting Cas9, published in the journal Cell, described how the team rebuilt the Cas9 system to find and chop up disease-causing RNA molecules.

In gene editing, the CRISPRCas 9 system uses an RNA probe that matches a specific stretch of DNA. Once bound to the right gene, the Cas9 enzyme cuts the DNA, which then can be inactivated or edited. The new system targets RNA, and chops it upinstead of editing it.

RNA, whichis largely composed of similar building blocks as DNA, has numerous roles in a cell. For instance, it is used to take a copy of a gene to provide instructions for the cells protein-making machinery.

At times, however, RNA molecules start accumulating what researchers call microsatellite repeat expansions. These are stretches of repeat RNA letters that disrupt the normal activity of the RNA. When found in messenger RNAs, they prevent necessary proteins from being made.

Anabnormal sequence also makes the RNA accumulate in cells, disrupting other cell operations. This can be seen in ALS that runs in families, andin diseases such as myotonic dystrophy and Huntingtons.

In ALS, such repeats are found in the C9orf72 gene, and cause about a third of familial ALS cases, or those that run in families,according to the ALS Association.

Testing the new tool in lab-grown cells derived from ALS patients with such mutations, the team showed that RCas9 could eliminate at least 95 percent of accumulated RNA, seen as dense clusters, or foci, in the cells.

They also discovered that using RCas9 freed proteins that normally bind to RNA in cells. When abnormal RNA starts accumulating in a cell, these proteins get tied up interacting with the aggregates, instead of binding to their natural targets. Researchers said that treated patient-derived cells eventually resembled healthy cells.

For the system to be useful as a human therapy, it needs to fit into a virus the most common way to deliver gene therapy. Normal Cas9 is too large to fit into thevirus typically used. The team solved the issue by removing parts of the Cas9 enzyme required for cutting DNA, making the enzyme small enough to fit.

Yet, many more questions need to be answered before the method can be tried in patients.

The main thing we dont know yet is whether or not the viral vectors that deliver RCas9 to cells would elicit 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.

The group has launched a company, Locana, that will work onpreclinical-trial development of the method with the aim of bringing it to patients.

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, said David Nelles, PhD, one of two lead studyauthors.

There are more than 20 genetic diseases caused by microsatellite expansions in different places in the genome. Our ability to program the RCas9 system to target different repeats, combined with low risk of off-target effects, is its major strength, added Ranjan Batra, PhD, the studys other lead author.

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Gene Editing System Revamped to Target RNA Aggregates Found in Inherited ALS - ALS News Today