How neuroscientists Brown are using CRISPR to speed up brain research – and more


PROVIDENCE, RI [Brown University] – The CRISPR gene-editing technique has made headlines around the world for its potential to alter the genetic makeup of organisms and to treat genetic diseases such as sickle cell anemia. It has vast potential in many fields, including neuroscience.

“Neuroscientists are currently using this technique to unravel how the brain works and hope to someday adapt it to offer treatments and cures for various neurological disorders, with some forms of blindness perhaps being the most imminent,” said Kate O ‘ Connor-Giles, Partner at Provost. Professor of Brain Sciences at Brown University. “The possibilities of neuroscience are wide open.”

CRISPR allows researchers to precisely cut and modify the DNA of a cell. Using CRISPR, scientists can probe the genes that underlie the functioning of the nervous system in model organisms by introducing mutations, including those associated with disease. This allows scientists to study the effects of changes in genes on the development, function and behavior of the nervous system.

Kate O’Connor-Giles is a Brown Associate Professor of Brain Sciences who uses CRISPR in her research.

CRISPR is made up of two components: Cas9, an enzyme that cuts DNA and is often called molecular scissors, and a synthetic RNA molecule called gRNA, which can be programmed to recognize specific sites in the genome.

“You can target Cas9 just about anywhere in the genome where it will then cut DNA,” said O’Connor-Giles, affiliate of Brown’s Carney Institute for Brain Science. “This then opens up a window of opportunity to re-code DNA by hijacking the cell’s DNA repair machines. It allows us to do all kinds of things, like removing one or more genes or introducing different types of mutations. “

O’Connor-Giles discussed how she and her team have used the CRISPR technique, as well as what neuroscientists like her hope to do in the future, before April 27. Carney Conversations Event where she will further explore the potential of gene editing technology in neuroscience.

Q: Why is CRISPR important for neuroscience?

Many of the genes that regulate the development, function and maintenance of the nervous system are poorly understood. Changing this is one of the main areas of research in our laboratory. As it becomes easier to determine which genetic changes lead to atypical neurodevelopment, many uncharacterized genes are linked to neurological disorders. CRISPR allows us to rapidly generate animal models to study how these genes work in an intact nervous system.

Likewise, CRISPR can be used to study gene mutations in human cells. Neurons can be induced from stem cells with the altered gene, as well as stem cells in which the disease causing change has been repaired by CRISPR. This allows neuroscientists to study the effect of genetic changes associated with the disease on a person’s exact genetic makeup to understand how this change alters the nervous system in the specific context of that person’s neurons. This is important because we all have slightly different genomes with small changes scattered all over the place that can alter the effect of a change associated with disease.

In combination, animal and stem cell models generated with CRISPR technology are powerful tools for understanding neurological disorders. We can use CRISPR to study the effect of gene differences on brain aging. We can also use CRISPR in model organisms to identify new genes that play important roles in the nervous system. The more we get there, the more likely it is that when a change in a gene underlies a neurological disorder in a patient, we will already understand what that gene does and the available treatment options, or promising avenues of investigation.

Q: When did you first hear about CRISPR and realize you wanted to incorporate it into your research?

In 2012, my lab wanted to use gene editing to study new genes that we had identified as candidate regulators of communication in the brain. We started by working on improving methods of gene editing in flies, which at the time was time consuming and often not possible.

We were following developments in gene editing closely and started paying attention to CRISPR as soon as Doudna and Charpentier Laboratories showed that it could be used to edit DNA in a tube. When several labs showed in January and February 2013 that CRISPR could work in cells, it was instantly clear that this approach was as simple as the first step in gene editing – cutting DNA at a specific site – was going on. get. We therefore decided to immediately focus our efforts on the adaptation of CRISPR to flies and formed a collaboration with the laboratories of Jill Wildonger and Melissa Harrison. We had our first proof that CRISPR worked in flies in April 2013, and we published the results the next month. This gave us the ability to essentially edit genes at will in flies, and we prioritized open distribution of our reagents and approaches to ensure that was true for the entire fly community. It was a pretty exciting time and I’m so glad I was a part of it. The impact has been long-lasting, with CRISPR completely revolutionizing our ability to study neuronal genes in the laboratory.

Q: How do you see CRISPR influencing the treatment and cure of brain diseases?

CRISPR dramatically expands our ability to study disease mechanisms in model organisms and stem cells so that we can understand why neurological function is negatively affected. This fundamental research is currently the area where CRISPR has the greatest impact. In our lab, for example, we are using CRISPR to study genes whose loss has been linked to intellectual disability but which has not been studied in the context of the brain. If it is also possible to use CRISPR to cure neurological diseases, this must be weighed against the risks associated with DNA breakdown. The delivery of CRISPR components to brain cells also presents a challenge. For this reason, retinal disorders involving more accessible neurons in the eye are currently the most promising candidates for CRISPR-based treatments in the nervous system.

Q: What are some of the challenges associated with using CRISPR to manipulate genetic material in humans?

I think there are three main concerns when considering manipulating human genomes. First, security – can we use CRISPR in a way that doesn’t risk introducing mutations? Breaking DNA is inherently risky. The cell will not necessarily repair the break as expected, and we could break DNA at unintended sites in the genome, accidentally introducing new mutations that could disrupt the function of other genes and cause different deleterious effects depending on the one (s). affected genes.

Second, the efficiency – can we actually drive CRISPR in humans with an efficiency high enough to be useful in the treatment of disease? As I mentioned, a major bottleneck here is the delivery of CRISPR components to the affected cells. This is especially true in the human nervous system with its billions of neurons.

And third, there are ethical concerns, for example, regarding equitable access to CRISPR-based therapies and the use of CRISPR to make changes to genomes that go beyond correcting changes associated with disease. This is a critical issue that goes way beyond science and should involve all of us to think seriously about how we do and don’t want to use gene editing in humans. This is one of the main reasons why it is so important that we all have a basic understanding of CRISPR, what it can and cannot do, and how that may change in the relatively near future.

Q: How is technology as a research tool changing and how can it be improved?

The precision and efficiency of CRISPR are improving steadily. And new CRISPR systems with distinct properties – such as targeting RNA instead of DNA – are constantly being identified. Scientists are also constantly devising new applications, such as the use of basic editors, which allow editing of genes without the risky introduction of DNA breaks, or the adaptation of RNA cleavage forms. CRISPR for the detection of viruses or bacteria. CRISPR is evolving rapidly on many fronts, and I think we will see a lot of progress in the years to come.

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