How to handle CRISPR: Formulating a responsible approach to gene-editing

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In February 2016, CIRM sponsored a workshop to discuss the impact of CRISPR, a gene-editing tool that is transforming stem cell research. The workshop was designed to enable the Standards Working Group  (SWG) to reflect on policies governing the review and oversight of embryo research support by CIRM.

After the workshop, we wrote a blog about some of the important questions that came up during the discussion. There is also a written and audio transcript of the meeting here.

Since then, the CIRM Team has been working with the co-chairs of the Standards Working Group to develop draft recommendations for how CIRM could address the workshop questions. The draft recommendations may be found here.

As we noted in June 2015, these deliberations and subsequent recommendations are designed to inform the responsible uses of genome editing technologies with CIRM funds. In particular, CIRM continues to place a priority on funding research that does not receive timely or sufficient federal funding – for example research involving human embryos.

As was discussed at the workshop, donors indicated strong support for embryo research for:

  1. Understanding human development and
  2. Creating stem cell lines.

Genome editing may be applied to both types of research.

The draft recommendations are intended to ensure such work may occur under high ethical standards. After the Standards Working Group review, the final recommendations will be forwarded to CIRM’s governing Board, the ICOC, for approval. We hope that will happen this summer.

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Timing is everything: could CRISPR gene editing push CIRM to change its rules on funding stem cell research?

CRISPR

Talk about timely. When we decided, several months ago, to hold a Standards Working Group (SWG) meeting to talk about the impact of CRISPR, a tool that is transforming the field of human gene editing, we had no idea that our meeting would fall smack in the midst of a flurry of news stories about the potential, but also the controversy, surrounding this approach.

Within a few days of our meeting lawmakers in the UK had approved the use of CRISPR for gene editing in human embryos for fertility research —a controversial first step toward what some see as a future of designer babies. And a U.S. Food and Drug Advisory report said conducting mitochondrial therapy research on human embryos is “ethically permissible”, under very limited conditions.

So it was clear from the outset that the SWG meeting was going to be touching on some fascinating and fast moving science that was loaded with ethical, social and moral questions.

Reviewing the rules

The goal of the meeting was to see if, in the light of advances with tools like CRISPR, we at CIRM needed to make any changes to our rules and regulations regarding the funding of this kind of work. We already have some strong guidelines in place to help us determine if we should fund work that involves editing human embryos, but are they strong enough?

There were some terrific speakers – including Nobel Prize winner Dr. David Baltimore; Alta Charo, a professor of Law and Bioethics at the University of Wisconsin-Madison  ; and Charis Thompson, chair of the Center for the Science, Technology, and Medicine in Society at the University of California, Berkeley – who gave some thought-provoking presentations. And there was also a truly engaged audience who offered some equally thought provoking questions.

CIRM Board member Jeff Sheehy highlighted how complex and broad ranging the issues are when he posed this question:

“Do we need to think about the rights of the embryo donor? If they have a severe inheritable disease and the embryo they donated for research has been edited, with CRISPR or other tools, to remove that potential do they have a right to know about that or even access to that technology for their own use?”

Alta Charo said this is not just a question for scientists, but something that could potentially affect everyone and so there is a real need to engage as many groups as possible in discussing it:

“How and to what extent do you involve patient advocates, members of the disability rights community and social justice community – racial or economic or geographic.  This is why we need these broader conversations, so we include all perspectives as we attempt to draw up guidelines and rules and regulations.”

It quickly became clear that the discussion was going to be even more robust than we imagined, and the issues raised were too many and too complex for us to hope to reach any conclusions or produce any recommendations in one day.

As Bernie Lo, President of the Greenwall Foundation in New York, who chaired the meeting said:

“We are not going to resolve these issues today, in fact what we have done is uncover a lot more issues and complexity.”

Time to ask tough questions

In the end it was decided that the most productive use of the day was not to limit the discussion at the workshop but to get those present to highlight the issues and questions that were most important and leave it to the SWG to then work through those and develop a series of recommendations that would eventually be presented to the CIRM Board.

The questions to be answered included but were not limited to:

1) Do we need to reconsider the language used in getting informed consent from donors in light of the ability of CRISPR and other technologies to do things that we previously couldn’t easily do?

2) Can we use CRISPR on previously donated materials/samples where general consent was given without knowing that these technologies could be available or can we only use it on biomaterials to be collected going forward?

3) Clarify whether the language we use about genetic modification should also include mitochondrial DNA as well as nuclear DNA.

4) What is the possibility that somatic or adult cell gene editing may lead to inadvertent germ line editing (altering the genomes of eggs and sperm will pass on these genetic modifications to the next generation).

5) How do we engage with patient advocates and other community groups such as the social justice and equity movements to get their input on these topics? Do we need to do more outreach and education among the public or specific groups and try to get more input from them (after all we are a taxpayer created and funded organization so we clearly have some responsibility to the wider California community and not just to researchers and patients)?

6) As CIRM already funds human embryo research should we now consider funding the use of CRISPR and other technologies that can modify the human embryo provided those embryos are not going to be implanted in a human uterus, as is the case with the recently approved research in the UK.

Stay tuned, more to come!

This was a really detailed dive into a subject that is clearly getting a lot of scientific attention around the world, and is no longer an abstract idea but is rapidly becoming a scientific reality. The next step is for a subgroup of the SWG to put together the key issues at stake here and place them in a framework for another discussion with the full SWG at some future date.

Once the SWG has reached consensus their recommendations will then go to the CIRM Board for its consideration.

We will be sure to update you on this as things progress.

CIRM Scholar Helen Fong on Stem Cells and Brain Disease

Helen Fong, CIRM Scholar and Research Scientist at the Gladstone Institutes

Helen Fong, CIRM Scholar and Research Scientist at the Gladstone Institutes

Meet another one of our talented CIRM Scholars, Helen Fong. She is currently a Research Scientist at the Gladstone Institutes and did her graduate work at the University of California, Irvine. Her passions include stem cells, disease modeling, and playing with differentiation protocols – the processes that tell stem cells to mature into specific tissues. As a CIRM Scholar, part of our educational training programs, Helen published four articles where she was listed as the first author. Her most recent one was a stellar study published in Stem Cell Reports using induced pluripotent stem cells (iPSCs) to model and understand a nerve cell-destroying brain disease called frontotemporal dementia.

We interviewed Helen to learn more about her work in stem cell research.


Q: What was your graduate school research on?

HF: I did my graduate work in the lab of Dr. Peter Donovan, who is a prominent germ cell and stem cell scientist, and was newly recruited to UCI when I began my studies. I was his first graduate student from UCI. Dr. Donovan’s research was focused on understanding the regulation of early human development using embryonic stem cells (ESCs) and how to improve human pluripotent stem cell culture. He was also interested in understanding the biological mechanisms that keep stem cells pluripotent (the ability to become all the other cell types in the body) and the genetic factors that are important for maintaining pluripotency. My graduate research was on understanding the basic biology of human ESCs. Specifically, I studied the role of the gene Sox2 in maintaining stem cell pluripotency and self renewal in human ESCs.

Q: What about your postdoctoral research?

HF: After my PhD, I decided to continue to work with stem cells because I knew that the field would continue to grow. There was still so much to be learned about these unique cells. I also genuinely enjoyed working with stem cells and couldn’t imagine not seeing them every day. I realized that I had a solid understanding of the basic biology of ESCs, but I wanted to use stem cells to study human disease. This ability is one of the huge selling points of working with human induced pluripotent stem cells (iPSCs) [which are created by reprogramming adult cells back to a pluripotent state]. The Gladstone Institutes was an excellent place to continue my training and to begin using iPSCs to understand neurological disease. I joined Dr. Yadong Huang’s lab in 2011 and am currently using human iPSCs to study brain degenerative diseases including frontotemporal dementia (FTD), progressive supranuclear palsy (PSP), and Alzheimer’s disease (AD).

My recent publication in Stem Cell Reports used human iPSCs from a patient with FTD as a model to understand the mechanisms behind this condition. This patient carried a rare genetic mutation in the MAPT gene called TAU-A152T. Several studies have reported a number of patients with this specific mutation that could put them at risk for developing FTD, PSP, and AD. However, it wasn’t clear what this mutation was doing to cause these disorders.

One of the ways you can study neurodegenerative diseases is using stem cells derived from patients harboring the disease causing mutations. We obtained human iPSCs made from the skin cells of a patient with FTD and this TAU mutation. I then used zinc finger nuclease (ZFN) genome editing technology to genetically correct the mutation back to the wild type (normal) sequence to see if removing this mutation in the patient iPSCs would generate healthier neurons (nerve cells) that don’t have symptoms of FTD. I was able to study the disease-causing effects of the TAU mutation by comparing healthy neurons I made from the corrected (normal) iPSC line to diseased neurons made from the TAU mutant iPSC line.

Neurons generated from FTD patient iPSCs. (Image courtesy of Helen Fong)

Neurons generated from FTD patient iPSCs. (Image courtesy of Helen Fong)

The neurons that I differentiated from the iPSCs carrying the TAU mutation showed an increase in TAU protein fragmentation [meaning the protein gets degraded and isn’t present in its normal form], an abnormal characteristic that can be associated with FTD and AD. We didn’t see this phenomenon in the neurons from the corrected (normal) human iPSCs, indicating that removal of this TAU mutation could improve the symptoms of these diseases. These results were exciting because we now had a culprit for what could be causing disease in these patients with this mutation. There is still much to be learned about the mechanisms of this mutation and the iPSCs have been an invaluable resource.

Q: What was your experience like as a CIRM scholar?

HF: CIRM has funded me for almost all of my stem cell training and research. I got my first CIRM training grant as a graduate student at UCI in 2006 and was funded for three years as a postdoc at the Gladstone. So I have CIRM to thank for all of my training.

When I first started out as a CIRM scholar, I believe I was part of one of their earlier pre-doctoral training grant programs. As the program expanded, I got to meet many of the other trainees at CIRM research conferences and interact with prominent stem cell scientists in the area. This was an incredible experience because I was exposed to stem cell research outside of my own institute, and I was able to meet all the big players in the field!

CIRM has also been very generous and provided me a travel allowance to attend any scientific conference of my choice. Over the years, I’ve gone to a lot of conferences nationally and internationally including ISSCR (International Society for Stem Cell Research), Keystone symposia, and the Society for Neuroscience (SfN). I have given scientific talks both at Keystone and SfN, and they proved to be excellent exposure for my work as well as a good place to get feedback. Another one of my favorite perks was the ability to purchase reagents for my own work at my own discretion, which gave me some freedom in dictating which direction I wanted my project to go. If I wanted to study a particular protein and needed a specific antibody to do that, I was able to get it with my CIRM funding.

Q: What’s next for your career?

HF: Currently, I am hoping to wrap up the project I am working on in the lab right now and generate a publication. I plan to continue to work on stem cells in the next step of my career and to work on challenging and cutting-edge projects. I feel fortunate for all the training and resources that I’ve received that got me to where I am today, and I hope to pass on many of my skills and knowledge to budding, young scientists.

Q: What is your favorite thing about being a scientist?

HF: I really enjoy the fact that I have so much control over the fate of my stem cells. They have the ability to turn into almost any cell type, and we’ve developed so many protocols to guide them into the exact cell type we want. They don’t always behave, but I think figuring out the personality of each and every cell line is part of the fun.


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