Hello Dolly

Kat - Also at the symposium, we heard from another pioneer of biology - Shinya Yamanaka, who won a Nobel prize for his discovery that just four molecules could convert any type of adult cell back into so-called induced pluripotent stem cells, which have the ability to become any type of tissue. And, as he explained to me, his research was directly inspired by Dolly.

Shinya - So, I was a physician a long time ago. I couldn't help many patients suffering from intractable diseases, including my own father. So that was why I changed my career from physician to a scientist. Because I thought, I believe it is basic medical science which in the future can help those patients suffering from intractable diseases. I did not expect I would work on stem cells when I started my scientific career. But because of many unexpected results of my experiments, I became interested in stem cells and here I am now.

Kat - So we're at the 20th birthday party I suppose for Dolly who was a sheep who was created by taking an adult cell, putting it into an egg cell, and then you could make a sheep. What did that tell us about cells that we didn't understand before?

Shinya - So Dolly really surprised us how flexible our cells are. Previously, we thought cell differentiation as irreversible.

Kat - Just one way - you go from egg to animal and that's it.

Shinya - Exactly. But because of the success of Dolly, we learned that it's not true. Differentiation is reversible. They can go back to the embryonic state. So by being inspired by Dolly, I started a project in which I tried to make embryonic stem cell-like stem cells. Not from human embryos but from adult somatic cells.

Kat - So, how did you start doing that? You've got these adult cells in a dish, you're looking at them going, "Okay, what do I do to you?"

Shinya - There was another previous work in which a scientist converted skin fibroblasts into muscle cells just by one factor. The factor is myoD. It's a transcription factor. By simply putting myoD, that factor into fibroblasts, Dr Weintraub was able to convert fibroblasts into muscle cells. So, that was another important lesson to me. We could convert cell fate by transcription factors. And also from Dolly, we learned that we should be able to reprogram cells back into the embryonic state. So, it's a combination of the two great previous studies which promoted me to initiate this project.

Kat - Because transcription factors, these are the molecules that basically turn certain genes on. They sit on the DNA, they turn genes on. So you've got that part of the puzzle, then you've got the Dolly part of the puzzle that tells us that you can go from one to the other. So then you just have to find the factors. How did you find those four factors, your Yamanaka factors that can turn adult cells back into stem cells?

Shinya - So, I thought those factors that can reprogram cells back into the embryonic state - ES cells. they should play important roles in ES cells themselves. So in the first 4 or 5 years in this project, I spent most of the time to identify as many factors as possible that played important roles in mouse embryonic stem cells. so then we just combined multiple factors which we had at that time and test them, and luckily, we were able to identify those four factors. So, it was a combination of our hardwork and our good luck.

Kat - How did it feel when you looked in that dish for the first time and you were like, "This has worked!"

Shinya - Actually, we thought it must have been some kind of mistake - some contamination or some kind of error. So, we repeated the same experiment many times and it worked always. So then we were convinced it must be true. Science is very tough. In many cases, we found we did something wrong. So, in this very special moment, we couldn't be just happy. We were very careful.

Kat - Something's got to be bad somewhere.

Shinya - So actually we didn't toast.

Kat - You did some toasting maybe when you got your Nobel Prize for it?

Shinya - No, not yet. When we become able to help patients, that's when we're going to have some good wine.

Kat - So you mentioned helping patients because now, we can take adult cells, you could take say, a skin cell from you or from me, you can treat it with these factors, you can turn it into stem cells. and then what can you do with them? What sort of cells can you make from these iPS cells?

Shinya - So at least in theory, we can make any types of cells that exist in our body like brain cells, heart cells, liver cells. So the potential is enormous. Of course at the moment, it is still very difficult to make completely mature heart cells or liver cells from iPS or ES cells but many scientists have been working very hard. I really hope in the very near future, we can do it.

Kat - I see some things like using 3D printing with tissues, with cells. is that the sort of thing you could do with iPS cells as well one day.

Shinya - It's also possible. So, we could use like heart cells, muscle cells, other types of cells as inks of 3D printers. At the moment, it's still like a scientific fiction but after 10 years or 20 years, who knows? It may be possible.

Kat - Another thing that maybe seems like science fiction is that certainly in mice, we can take iPS cells and we can make germ cells. we can make eggs and sperm. Again, is that something that could happen in the future, your mummy and daddy could be skin cells?

Shinya - It's possible but again, we need to discuss with not only between scientists but also with the general public, and also couples suffering from infertility, regarding how much we can do our research. So our goal is to help patients but scientists alone cannot decide how much we can proceed. So it's a very naïve question.

Kat - I went to university and that first year was when the announcement was made about Dolly the sheep so my whole adult life as a scientist has been an incredible time. How does it feel to be working at the cutting edge of such an incredible and exciting field?

Shinya - Well, that's one of the reason why we do science. Science is full of surprise. It's unpredictable. In many times, it's very tough. Scientists are having a hard time almost every day but sometimes it gives us wonderful moment. So that's why we cannot stop doing science. That's the beauty of science.

Kat - Nobel Laureate Shinya Yamanaka, from the Centre for iPS Research and Application in Kyoto.

Kat - While there was much talk at the symposium of mammals, the Roslin Institute's Lissa Heron is working with a different type of agricultural animal - chickens. Although chickens can't be cloned in the same way that mammals can, they can be genetically modified, meaning that their eggs might provide us with a lot more than a tasty breakfast in the future.

Lissa - Well, chickens are a really useful system. They've been used historically for studying developmental biology, development of the embryo. But they're also compared to large animals like sheep or cows. They're much easier to keep and you can keep a lot more chickens in the same kind of space that you would keep sheep. They're a lot cheaper to feed as well. They have a shorter life cycle, faster breeding cycle, and they're really easy to scale up. In terms of pharmaceutical production, the egg is a really great system because it produces a lot of protein. You don't need to disturb the hen really because you just take the eggs and that's it. and there's an easy way of now making the genetically modified chicken so that you produce a lot of whatever protein you want in the eggs. The other benefits of chickens are that they can make proteins that behave more like human proteins compared to some cells and some other mammals. And so, when you give these proteins to humans as a therapeutic, they are less likely to cause an immune response - a negative immune response and they're also more likely to be active compared to proteins made in other systems.

Kat - So, what sort of drugs, what sort of molecules are we talking about here that you could make in chickens?

Lissa - So, a lot of the classic drugs that people are familiar with like aspirin or paracetamol, these are small molecules that can be synthesised in a chemistry lab. But a lot of the newer drugs that are having a lot more success in treating cancers and chronic illnesses are actually proteins. The very first drug that was actually made this way on the pharmaceutical market was insulin. So insulin is a protein made by cells in your body and people who were diabetic can't produce this. And so, they used to have to purify it from animals. Obviously, a lot of potential for infections and other problems and also it's cruelty, you have to kill the animals to get the insulin. So, they started looking to see whether we can make this in bacteria. and fortunately with insulin, you can. It's a relatively simply protein. So they started making it in a bacteria and that way, you can have much greater control over the cleanliness of the protein and how safe it is. You can make little tweaks, the sequence, to make it more active or last longer in the body, all these sorts of things. So, once you got insulin successfully used in human patients, we started thinking, "What else could we make for patients?" more and more of these sorts of things have been coming up. So you have what are called monoclonal antibodies that target cancer cells. An example of that is Herceptin, and then you also have things like interferon alpha which is used to treat hepatitis and also various cancers. So you have all these sorts of proteins but a protein can't be synthesised. It has to be made in a cell system because it's a very complex biological process and it's a very large molecule. So, it needs to be expressed and it needs to be folded properly and some of them have to have sugars added to them and various modifications like that. So you need a more complex biological system to make them.

Kat - So, if that complex biological system is the chicken's egg, how do you get the genes that make the proteins into the chickens?

Lissa - We use a system called a lentivirus. This is a type of virus that is actually related to the HIV virus. These viruses are really useful because they're able to integrate into the genome of your target animal. They are not silenced like a lot of other genetic modifications that are made because the lentivirus needs it to replicate eventually. But we remove the ability of the virus to replicate. So, we're only using the bit of the virus that inserts into the genome and expresses and that's it. So, once you put the virus into the chicken, there's no more virus made. There's not any infectious agents or anything. But that puts the gene into the chicken and that gene is also attached to a promoter which is a bit of DNA that tells the cells to make a protein in a particular place. In this case, it's the promoter that is used for ovalbumin which is the protein that is most abundant in eggs, in egg white. And that then drives the expression of whatever gene that we've put in for expressing another protein.

Kat - And then presumably, when the eggs are laid, you just get the egg white and get the protein out the other end of it.

Lissa - Yes, that's exactly it. we just dilute the egg white down and remove one of the proteins from it which is called ovamucin and that's the protein that creates the kind of jelly-like structure of egg white. So we have to get rid of that so that we can access the rest of it and then we can run it down a standard chromatography column. So this is how all proteins are separated whether for research or for pharmaceuticals. Because the egg only has about 12 proteins in it, it's actually really easy to separate out compared to maybe trying to purify something out of a cell that has hundreds and thousands of proteins.

Kat - How do you know that this works? Are there any drugs that are already made in chicken's eggs and what are the kind of drugs are you working on?

Lissa - So there are actually three drugs on the market that are made from transgenic animals. The very first one was approved in 2009 and that's from the milk of a transgenic goat. There's another a couple of years later which was from the milk of rabbits. I don't know how they milk rabbits so don't ask.

Kat - Carefully. With very small hands!

Lissa - Yes. I just picture there are some very tiny little milkers. And then just in the last year and a half or so, there was another drug that was approved and that is made in transgenic chickens which use pretty much the same methods that we do.

Kat - Given that this seems like an incredible system for making drugs, molecules, that are really active in humans and could be really useful in medicine, is it then feasible? I mean, near where my mom lives, there's a nice free range chicken farm. There are some chickens running around. Presumably, you're going to need more chickens than that.

Lissa - It depends entirely on the drugs you're looking at. So some drugs actually only require a very small dose. And so, you would only maybe need a few hundred chickens and that would do you for your market. There are others where you would probably need farms of hundreds of thousands of chickens. In terms of the feasibility of that and obviously, you have environmental regulations and about having livestock animals, the chickens would have to be indoors. You can't have free range chickens because they might be exposed to outside infections and things eaten by foxes and that sort of thing. You don't want that. But the likelihood of using chickens to replace every single pharmaceutical protein production is very unlikely. It wouldn't be suitable for every single kind. So I think that the thing where you're really going to be targeting these is where you need to make a biologic in very large quantities for a low amount of money but where the dose doesn't need to be that big. So one of the things that we're targeting is actually the animal health market because at the moment, animals are priced out of the biologic's market because it's too expensive to make and people can't afford to pay lots and lots of money for an antibiotic for their dog or treatment for livestock animals. So, these sorts of things where you can't afford to pay a hundred pounds for a dose for each pig you have or each cow you have. But if you can bring that price down by producing it in chickens, then you've suddenly got a big market open to you where you can treat a lot of animals, you can treat companion animals, you can treat livestock without having to overuse antibiotics or without having to just let these animals die because there was no treatment available before.

Kat - The Roslin Institute's Lissa Heron. And if you want to find out more about the legacy of Dolly, take a look at the Roslin Institute's special website - that's
dolly.roslin.ac.uk or you can follow
@Dollyat20 on Twitter.