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22 September 2023

Gene therapy in developing countries. Alžběta Ressnerová is working on an easier application of CRISPR-Cas9

"Basically, we have the same dilemma as Oppenheimer. Every idea, every tool can be misused. Nowadays, we no longer ask if we can improve humans. We can, and easily. But we must ask whether we should, whether it is really necessary." At the Innovative Genomics Institute in Berkeley, CEITEC BUT PhD student Alžběta Ressnerová researched how to deliver "genetic scissors" to a designated target in the body and remove an unwanted mutation that causes an incurable disease. Take sickle cell anaemia, which killed 376,000 people in 2021. Where are the limits in "editing" people? What does the democratisation of gene therapy mean, and what is the prescription of a scientist who has already had two postdoc offers in America?

You studied for your master's degree in Berlin, did you want to continue your studies there?

I have to admit that I was burnt out at the time because the studies were very demanding and I was going through a difficult life situation, so returning to the Czech Republic meant returning to harbour for me. I planned to stay for a year or two and then continue my studies abroad. However, a very interesting offer came from CEITEC – research with nanorobots, which I was so excited about that I decided to stay here for my PhD. In retrospect, I definitely don't regret it.

You originally considered trying Harvard, why did CEITEC win in the end?

The freedom was the deciding factor for me. I could take my research in the direction I wanted. My supervisor was very supportive and gave me a free hand. That's not standard. It's often the case that the thesis supervisor tells you what to do and you have to meet their hypothesis that they want to prove. There's a lack of creativity. This is an approach that students all over the world encounter. Finding a supervisor who will offer you freedom is a rarity.

You studied molecular medicine, why did you switch to nanotechnology in Brno?

I've always wanted to combine gene therapy with the nanoworld. Although initially I took a little detour with Prof. Martin Pumera and focused only on nanorobots. Eventually, however, I turned my research focus back and became interested again in the CRISPR method, which I was researching in Berlin. This is a genetic engineering technique that allows us to precisely edit the genomes of living organisms. The problem was that my supervisor at CEITEC is an expert mainly in nanotechnology, and I basically have no mentor in the other branch – gene therapy. So, I contacted the American Institute and applied for a Fulbright scholarship.

Which you received, specifically a Fulbright–Masaryk scholarship. Congratulations! How was the selection process?

Thank you. I had to have written a research project that I wanted to pursue in America, a CV, a letter of invitation from the host institution, three letters of recommendation, of course excellent English, and I also had to prove my active participation in civic or public life, just like Tomáš Garrigue Masaryk had to. When you interview with the selection committee, you have to defend your internship. You have to have a bulletproof argument for why the research can't be done somewhere in Europe – to avoid candidates who don't want to go there for the research but for a vacation in America.

How did you present your argument?

For me it was simple. The Innovative Genomics Institute in Berkeley is the best in the world in CRISPR research. The institute was founded by Nobel Prize-winning biochemist Jennifer Doudna, who in 2012 co-designed the CRISPR-Cas9 system as a programmable genome-editing tool, which is considered one of the most important discoveries in modern biology. It was for this that she and her colleague Emmanuelle Charpentier won the Nobel Prize three years ago. This is where the research is furthest along and is generously funded by the Californian government.

Was the scholarship enough or did you have to earn extra money?

I didn't have to. It's prestigious and more than 100% enough just to do research. Plus, I didn't even have to worry about a visa, I just flew out. But I ran into problems in the first two months that delayed my work, so I extended my fellowship from the original ten to twelve months, even though ten is the maximum. The research is so important that it was necessary for me to stay. It was great that the Fulbright committee gave me the go-ahead. And my colleagues in the lab at CEITEC helped me with those initial problems, which led to my host institution establishing a collaboration with my home lab.

What did you do in America?

In my project, I targeted primary immunodeficiencies (various severe inborn errors of the immune system), which are sometimes caused by a mutation of just one letter in the genome, so the solution is essentially easier than when multiple genes are affected. Institute is connected to major hospitals in San Francisco, giving us access to samples of patients who suffer from a variety of diseases. We worked with families with primary immunodeficiency and tried to create a tailored therapy for them. The lab, where I worked, is involved in platform development to deliver CRISPR-Cas9 to target cells.

How can we imagine the function of CRISPR, namely genome editing?

CRISPR-Cas9 is an absolutely revolutionary technology that opens the door to the treatment of many genetic diseases. It consists of an enzyme (Cas) that acts as molecular scissors that precisely cuts the DNA, and a "guide" that directs the enzyme to the place where we need to make a change in the genome. We can use this to remove a gene that is making " trouble" or, conversely, to make a dysfunctional gene work. As powerful as CRISPR is, you can't just inject it into a person's vein. You have to "load it onto a trolley" that gets it where we need it to go in the body. And it's the development of the cart that's my job.

You worked with a sick family, does that mean you know them personally?

In America, there are very strict rules about how patients' biological material can be handled. I don't know them, I've never met them, and at the current stage of my research I'm not even using their cells yet. We'll get their sequenced genome and see what's wrong. In the lab, we'll create a model of the mutation and try to figure out a way (find a suitable "cart" for CRISPR) to fix it. And only when it works flawlessly can we write the application and use their lymphocytes. If that works too, we'll write a grant and do a clinical trial.

How serious are the diseases you are trying to treat?

For the most part, the institute deals with sickle cell anemia, but primary immunodeficiencies are also something we want to deal with because it would improve people's quality of life in a huge way. One of the immunodeficiencies I focus on limits people's lives to just a few years. Three-year-olds, four-year-olds are dying. It's pretty horrible, and they only have a mutation in one letter – they have a G instead of an A. CRISPR could solve this quickly and easily, which is why we're working hard on it.

What's specific about the "troley" you developed?

I can't reveal that (laughs). I can only say in general terms that I am trying to come up with ways of transport that are cell-specific. This is important so that we can insert CRISPR into the body intravenously. Imagine trying to deliver CRISPR to the brain, but we have thousands of different cell types in the body. If the "cart" wasn't cell-specific, the percentage of CRISPR getting to the target organ is awfully small. It's more likely to get lost somewhere. That's why we're trying to design it to find the cells it's programmed for. But be careful, it's not a nanorobot. We don't control it in the body anymore, and it's not driven by anything.

You mentioned that your research is very important, can you explain its contribution?

The current clinical trials are focused on the application of CRISPR on blood cells. Sickle cell anemia is related to erythrocytes, immunodeficiency is related to lymphocytes. The way clinical testing currently works is that we take lymphocytes from the patient, repair them in the lab and put them back into the body. The main disadvantages of this ex-vivo method are the huge financial cost and the equipment, which is not commonly available in hospitals. In clinical trials, CRISPR has already cured several people with sickle cell anaemia, but outside of trials it would be the preserve of the rich. The institute's vision is to democratise gene therapy so that CRISPR can be used in developing countries without the need to laboriously pull cells out of the body and put them back in.

So CRISPR could be injected by doctors around the world?

It should be that simple. The therapy will be so powerful and well-made that it can be injected into a vein. You go to the doctor, he injects you and you go home. You don't have to travel anywhere or be hospitalized. That's why the cell specific targeting I'm working on here is important.

That's a great idea. I assume the reason the institute focuses on sickle cell anemia is because it affects mostly people from Africa?

Yes, and because of the injustice. Sickle cell anaemia affects 8 million people and is only found in the black population. One hundred thousand people in America alone are living with the disease. Yet research funding is so ridiculously low that it's a disgrace. When you compare that with the money going into research into diseases that only white people suffer from, it is a mockery. Research into cystic fibrosis, which affects 30 000 people here and causes a comparable reduction in quality of life and mortality, has a budget several times larger. There are 280 specialised centres here for the treatment of cystic fibrosis and only 30 for sickle cell anaemia. The racism in funding research into the disease is really considerable, and we want these people to be able to lead full lives. Historically, everyone has treated them pretty badly.

Ethics go hand in hand with noble values. Where are the limits of editing the human genome?

It's great that you mention it. I'm lecturing on the subject. The last time I spoke at the Czech Centre in New York, it was very well received, so it's clear that the ethics of gene therapy resonates with people. We scientists are also thinking about ethics and of course we are interested in it. Jennifer Doudna herself lectures on this subject all the time and has a very radical view on where we should use CRISPR and where we shouldn't. She is against the "enhancement" of the human race.

Do all scientists have the same opinion?

The majority. Unfortunately, there are people who have crossed that line. In 2018, Chinese scientist He Jiankui presented his experiment using CRISPR to modify twin embryos to make them resistant to HIV and have them born. Huge scandal. In addition, research has emerged which found that because of this, they may have enhanced brains and may be more intelligent than their peers. Everyone condemned him for it, even Communist China, which subsequently banned such experiments. The question is whether we can trust it.

It's also suggested that CRISPR could be used as a weapon. Kind of an evil Captain America. Is that realistic too?

The evolution of super soldiers is entirely possible, and I lecture on it too, though everyone looks at me to see if I'm serious. It's not science fiction. There's a species of dog in the world that's been modified to have super-muscles. He looks absolutely ridiculous – a sort of canine Rambo. The question is, if we can do it in dogs, can we do it in humans? And the answer is yes. We don't really care if it's a dog embryo or a human embryo. It doesn't make that much difference. Just because we can do it doesn't mean we should. We're so far advanced now that we're not asking if we could do it, we're asking if it's the right thing to do. And we must never stop asking.

Where is the boundary between what diseases can be treated with this method and which ones cannot?

At the moment, development is focused on what is most important. We are starting with fatal diseases and illnesses that affect a huge number of people and impair their quality of life. In Africa specifically, cheap treatment of sickle cell anaemia with cured patients would not only improve the quality of life in general, but also get the local economy moving. It would relieve the health system, which could focus on something else... Then there is also the possibility of a cancer cure on the table. I've been looking into that after my nano-robotics phase at CEITEC. The question of how far we can go in treatment is still unanswered. But we are still a long way from the point where we will have to actively address it.

You just came back to the Czech Republic, what happened to your research?

I passed the research to the people who came after me. I needed to get some experiments done so I could follow up on them in the Czech Republic. But it won't be easy because we are not as well equipped and funded as the institute in America. However, the research results so far are encouraging. We plan to continue to collaborate on this and hopefully we will be able to publish it.

What is the recipe for a successful career as a scientist?

Czech science is lagging behind in some respects, so I think it is absolutely essential for Czech scientists to have foreign experience. I myself will definitely want to travel for a postdoc. I must say without exaggeration that working in America was one of the most important experiences of my life. And I am so grateful for the Fulbright Scholarship, otherwise I would never have gotten here. The scientific community here has been incredibly enriching. I've had the opportunity to get a glimpse under the hood of an institute where the best CRISPR science in the world is done. There are many things I want to do differently now.

For example?

Weekly meetings across the labs to present the results of the previous week's work. It's quite a lot of preparation, but incredibly productive. You can solve a problem that you would otherwise have been puzzling over for weeks, or maybe your colleagues will point out a bug that you wouldn't have discovered until three months later. It saves you time and money and moves you forward. I'll take this style with me.

What would you say to budding scientists?

Don't be afraid. Email foreign experts in their fields and start collaborating. I always imagine the worst-case scenario that could happen. Often it's just that, for example, no one responds to my email, which is not such a disaster. If it worked for some "Betty from the Czech Republic", why wouldn't it work for you? Forget about embarrassing yourself. I've never met anyone abroad who looked down on me.

Source: CEITEC BUT

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