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Today, we talk about stem cells and how we can convert differentiated body cells into induced pluripotent stem cells (iPS cells) by using the Yamanaka factors. Stem cells are special types of cells which have the capacity to self-renew and the ability to generate differentiated cells. Differentiation is the process in which stem cells specialise (eg they become a neuron). In other words, stem cell differentiation means that the potency of a cell becomes more restricted.
There are embryonic and adult stem cells. While embryonic stem cells are mostly pluripotent (can become nearly all existing cell types), adult stem cells are multipotent, oligopotent or unipotent. Hematopoietic stem cells are multipotent stem cells, as they give rise to all kind of cells in our blood.
For decades scientists thought that differentiated cells cannot be reprogrammed into stem cells. This paradigm however shifted when Shinya Yamanaka identified and activated the Yamanaka factors in fibroblasts (Yamanaka factors are the four genes Oct3/4, Sox2, Klf4 and c-Myc). In his experiments, Yamanaka infected murine cells with viral particles which contained the Yamanaka factors. As a consequence, the differentiated cells became induced pluripotent stem cells. For the generation of iPS cells by the usage of Yamanaka factors, Shinya Yamanaka was awarded with the Nobel Prize in Physiology or Medicine in 2012.
There are numerous possible applications for iPS cell technology (using Yamanaka factors). We can use iPS cells to generate tissues or organs for organ transplantations. In Germany for example, the annual number of post-mortem organ donations in Germany has declined by more than 30% since 2010.
One major drawback of using iPS cells, however, is the risk of provoking cancer in the patient. Many of the genes, which are active in stem cells through Yamanaka factors are also active in cancer cells. Therefore, scientists are trying to develop safer protocols for the generation of stem cells (which partially include Yamanaka factors).
In 2014, the first clinical study using human iPS cells products was launched. Here, iPS cells were generated from a patient who suffered from macular degeneration. These iPS cells were then transformed into retinal pigment epithelial cells and transplanted into the eyes of the patient. The therapy has resulted in positive results, stopping macular degeneration and improving the vision of the patient. Further studies need to be conducted in order to start the era of iPS cells based transplanation.
For your further research:
Takahashi, K., & Yamanaka, S. (2006). Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. cell, 126(4), 663-676.
Hamazaki, T., El Rouby, N., Fredette, N. C., Santostefano, K. E., & Terada, N. (2017). Concise review: induced pluripotent stem cell research in the era of precision medicine. Stem Cells, 35(3), 545-550.
Shi, Y., Inoue, H., Wu, J. C., & Yamanaka, S. (2017). Induced pluripotent stem cell technology: a decade of progress. Nature reviews Drug discovery, 16(2), 115.
Music:
Intro:
Light Sting by Kevin MacLeod is licensed under a Creative Commons Attribution licence (creativecommons.org/licenses/...)
Source: incompetech.com/music/royalty-...
Artist: incompetech.com/
Transitions:
Light Thought var 3 by Kevin MacLeod is licensed under a Creative Commons Attribution licence (creativecommons.org/licenses/...)
Artist: incompetech.com/
Images:
"Shinya Yamanaka" by Rubenstein, CC BY 2.0
"NIH 3T3" by SubtleGuest, CC BY 2.5
"Medical students" by Sydney Uni, CC BY 2.0
"Shinya Yamanaka - Nobel Lecture" by © The Nobel Foundation
"Stem Cells" by Amoeba Sisters, www.amoebasisters.com/
"Muscle Tissue" by OpenStax, CC BY 4.0
"Neuron" by RobinH, CC BY-SA 3.0
"Hematopoiesis" by A. Rad and Mikael Häggström, CC BY-SA 3.0
"Brain" by _DJ_, CC BY 2.0
"Nobel Prize" by Royal Karolinka Institute, CC BY 2.0
"Cell" by domdomegg, CC BY 4.0
"DNA" by Sponk, CC BY-SA 3.0
"Retrovirus" by T Splettstoesser, CC BY-SA 4.0
About Clemens Steinek:
CLEMENS STEINEK is a postgraduate student/youtuber (LifeLabLearner) who is currently conducting stem cell research in Germany.
15 июн 2019
