Stem cells - the future: an introduction to iPS cells

one of the most extraordinary scientific discoveries of this century was made by dr. turned scientist working in Japan Shinya Yamanaka had been involved in the field of stem cells for ten years when his experiments changed the way we understand human biology Shinya Yamanaka is a medical doctor and a scientist he was interested in finding a way to treat incurable spinal cord injury patients I was an austere ik surgeon so I didn't do any stem-cell research at that time it was like 20 years ago but I had many difficult patients suffering from spinal cord injuries and there are no treatments to those patients so that's why I became interested in basic research because I thought by doing basic research one day I may be able to treat help those patients shannon yarmulkes desire to help patients led to a brilliant experiment this took us to the limits of our knowledge in fact it took us beyond them and reveal something really extraordinary there are two types of stem cells adulthood tissue stem cells make cells in their own tissues blood stem cells make blood muscle stem cells muscle and so on there is another type of stem cell the embryonic stem cell these cells are called pluripotent because as well as making copies of themselves they can become any of the different types of cell that make up the human body so the point about the adult tissue stem cells is that these are dedicated cells to repair and maintain particular tissue the embryonic stem cells represent very early stage in development when there is no muscle or blood or bone there's nothing else really there's just then development starts with the early embryo and these pluripotent founder salts and things become more and more restricted and channel that's how the body is built and it would be a complete chaos if cell types could stop turning into one another Shinya already knew from earlier experiments and cloning that development could be reversed that a specialized cell which scientists call differentiated can produce embryonic cells but no one knew how this process worked to find out sheeni looked for clues inside the cell I knew that X or embryonic stem cells have factors that can convert skin cells back to embryo embryonic state so that's why we decided to search for such factors scientists had no idea what these factors were or how many would be needed Shinya went back to basics examining the biology that gives cells their individual identities we already knew that each cell in our body contains something that determines the what sort of tissue the cell becomes it's so identity these are the genes in the nucleus the nucleus in each of ourselves contains 23 pairs of chromosomes made up of long strands of DNA this is divided into sections or genes that direct the cell to make particular proteins these proteins which scientists sometimes call factors of what gives us cells their different identities all of our cells contain the same genes but in a skin cell only the genes that make skin proteins are turned on the active genes are always in the unwound open areas of the chromosome all the other genes that would make a liver a heart or an embryonic cell are turned off they are tightly wrapped up and locked away the remarkable thing that Shinya Yamanaka did was to question whether a cell had to stay differentiated might it be possible to make an already specialized cell turn back into an embryonic stem cell in the laboratory he wondered if the same proteins that keep embryonic stem cells pluripotent might be able to reprogram the specialized identity of a differentiated cell he started with a list of over 100 Possible's he didn't know if they operated alone or in combination which would mean over a million possible variations using an off-the-shelf computer program Shinya Yamanaka was able to distinguish the 24 most likely candidates it took years of work the next step was to narrow down factors from 24 factors into whatever required and we found that 4 out of the 24 factors was essential he took a combination of 4 factors that normally only act together in the embryonic stem cell and inserted them into a skin cell in a process we don't fully understand the chromosomes began to unwind Sheena's factors could now attach to the genes which make embryonic stem cell proteins the proteins called opt for socks to klf4 and Semak overwhelmed the competing message from the skin genes fooling the salient is thinking it's in an embryonic environment you as these reprogrammed cells replicate they become more and more like embryonic stem cells until eventually they are indistinguishable from this state it can now be used to produce any cell in the body what I discovered was that we can convert skin cells back to embryonic state so we can make stem cells from skin cells all we have to do is to add three or four factors into skin cells that's all we need from ES cells and we rock stem cells we can make all the cells that exist in the body however we have to destroy embryos in order to generate a year cells but with our technology we don't have to use embryos anymore we can make ES like stem cells directory1 from skin cells Shinya Yamanaka had made a new type of pluripotent cell called induced pluripotent stem cells or iPS cells he first made his discovery studying mice and quickly showed it also worked for human cells this was an extraordinary discovery Shinya Yamanaka had proven he could turn a skin cell backwards in time and then forwards into any other cell in fact it didn't just work with skin he could turn any differentiated cell into an IPS cell this generated headline news and astonished scientists all over the world my reaction was first of all that this was one of the most profound scientific developments in our lifetime it completely turned upside down everything we'd been taught about development so we had always been taught that development was irreversible everything was a one-way street but in fact that's not true so our notions about development we're clearly wrong it isn't so fixed as we thought it was it means we have to be more open in our thinking to what is biologically possible only Shinya Yamanaka imagined that it might be possible to reprogram and differentiate itself on just a handful of protocols other scientists were quickly able to reproduce genius findings the first step is to remove the meeting we used to culture our skin cells now we are adding a new medium containing the reprogramming factors in a couple of weeks we shall have some IPS cells in this dish so as a result of infecting the skin cells what you have after a few days is this nice colonies of cells see here two clear examples so they are Vann ESL mythology but now we also know that there ever quired is in Viana stem cell status the way is now wide open to stem cell medicine induced pluripotent stem cells or iPS cells are a whole new kind of cell they can provide better ways of tackling disease and potentially regenerating the body one of the major differences between IPS cells and embryonic stem cells is that IPS cells can be generated from individual patients that means they are genetically identical to the individual patient and that means if we generate for example cells for transplantation from IPS cells they will not be rejected they will not be recognized by the patient's immune system here we see for the first time a prospective to derive specialized cells for example from the patient's skin and to mend these cells into brain cells into insulin producing cells or into heart cells which can then be used to supply this individual patient without the risk of transplant rejection the way reprogramming works to make IPS cells is still mysterious although it's technically easy it doesn't always work completely and can produce cells with unexpected changes in their genes scientists are now investigating how to produce perfect IPS cells that could be safe to use for treating patients and although IPS cells provide a way of making pluripotent cells without using human embryos which relieves an important ethical concern they themselves have raised entirely new issues I wanted to avoid the usage of human embryos so uh I think we have succeeded that goal but as soon as we succeeded I realized that we have generated new ESCO issues this was something no-one had predicted IPS cells are in theory a belay both sperm and eggs so they could one day be used to produce an embryo which could be implanted and carry to term so one day it may be biologically possible to create a human being from a single piece of skin should we stop this research it's too late making IPS cells is really quite simple for anyone with basic biological training like all new technologies we have to weigh up the potential benefits and potential drawbacks for instance studying how to make functional human sperm or eggs from IPS cells may bring benefits but infertile couples scientists believe that the creation of IPS cells means stem cells have entered a new era teaching us how to control cell identity they expect IPS cells to provide us with new tools to study diseased and normal cells in the laboratory meaning that drugs for diseases like Parkinson's can be tested on lab grown human cells they also hope to learn why human cells die in degenerative diseases like Alzheimer's a key problem in drug development is bad down individual candidate tracks face the human system only at a very late stage of drug development until then there's usually up to eight years of development which has gone into this individual drug now using human cells at the very early stage of drug development will help to identify compounds which do not work in human cells I think this this will definitely create new opportunities to identify new drugs and speed up the process by which drugs come through but it will just revolutionize the approach to studying inherited disease given a sample of disciple but only one essence on as I've already filled oh yeah but I mistake what I'll be talking to you on what Pelosi's is only for doctor as we thought okay I guess this is the most important discovery in stem cell research since embryonic stem cells were first discovered in 1981 in my personal opinion it will go down in history as one of the most amazing discoveries of all time

Channel: EuroStemCell

Views: 173,126

Rating: 4.9148936 out of 5

Keywords: stem cells, ips, induced pluripotent stem cells, Shinya Yamanaka, Ian wilmut, adult stem cells, regenerative medicine, science, research, Educational, biology, animation, Medicine (Field Of Study), stem cell research

Id: Q9-4SMGiKnE

Length: 16min 42sec (1002 seconds)

Published: Wed Oct 24 2012