| 1 | Ioana the Iguana | Induced Pluripotent Stem Cells // Engineering Explainers #2 | 5521 | 141 | 5 | 63.4 | positive | 4:19 | Induced pluripotent stem cells. You may have heard these words thrown around in articles about regenerating organs or making human tissue, but what actually are they and how do they work? Let's start from the beginning. Cells are the building blocks of all living tissues. They come in a variety of shapes, sizes, and functions. Cells are a generalized type of cell from which specialized cells develop. They can either make copies of themselves or they can differentiate into any tissue, like the brain or the liver or the heart or anything else. If we go even deeper we can talk about embryonics themselves, which are basically the earliest cells in an embryo before they start to differentiate into specific tissues and organs. We call them pluripotent to mean that they have the ability to become any cell type in the body. So far so good, but what does it mean to induce pluripotent stem cells? As you can imagine, harvesting embryonic stem cells is not that easy and it comes with a range of ethical issues. So in 2006 researchers came up with the idea to make their own stem cells in a lab without the need for embryos. Sure enough their idea became reality. In 2012 Sir John Gordon and Shinia Yamanaka jointly received the Nobel Prize in Physiology and Medicine. They discovered that mature cells can be reprogrammed to act like pluripotent embryonics stem cells. The procedure is surprisingly simple. A hair follicle or a very small piece of skin is collected from a patient. Then it's placed on a dish and four proteins called transcription factors are added. They are nicknamed the Yamanaka factors and they are oct 3, 4, KLF4, C-MIG and SOX2. After a few weeks the cells are reprogrammed to look and behave just like pluripotent stem cells. So now we have a petri dish full of pluripotent stem cells. What can we do with them? We take a page out of the developmental biology book and effectively guide the stem cells to become whatever we want them to become. We place them in a soup or culture medium that simulates our desired final tissue and we add the growth factors that are expressed during development. So if we want to make a motor neuron we add the chemicals that normally transform an embryonic stem cell into a neuron and same for any other cell type. We follow the body's recipe to make any tissue we desire. Now I know this sounds a bit like magic and it totally blew my mind when I first encountered it. But there are in fact some obstacles and rules to follow. It takes months to go through the entire process and the reprogramming efficiency is not great. But it is an extraordinary feat of science. To be able to just collect a piece of skin or a strand of hair, make it behave like a pluripotent stem cell and then just instruct it to become a completely different type of cell. So what's next? At the start of this video I mentioned that you have probably heard of IPSEs in the context of making artificial organs and that is definitely an area of research but there is so much more to stem cells than just that. Researchers can model disease using IPSEs from a patient to analyze the phenotype and understand the physiology of the disease. Also they can bypass clinical trials and instead just test drugs directly on the differentiated cells. Finally, IPSEs can be used in cell or gene therapies. IPSE-based treatments have been researched for a large number of diseases such as Parkinson's disease, ALS, diabetes or various blood and heart diseases. I hope you enjoyed this video and learned something new today about induced pluripotent stem cells. Thank you for watching. Don't forget to like, comment and subscribe for more science content. | ↗ |