"iPS cells" are not only very similar to ES cells in cell morphology, growth characteristics and expression of stem cell markers, but also almost the same as ES cells (embryonic stem cells) in DNA methylation pattern, gene expression profile, chromatin state and chimera-forming animals.
IPS cells and ES cells can produce all cells except embryos. If used in medical treatment, all diseases can be cured theoretically-all bad tissues are removed and replaced with normal tissues that grow again.
Research history of iPS cells In 2006, the laboratory led by shinya yamanaka of Kyoto University published a paper in the world-famous academic journal Cell, which reported the research of iPS for the first time in the world.
They introduced four transcription factors Oct3/4, Sox2, c-Myc and Klf4 into mouse embryonic or skin fibroblasts, and found that they could induce their transformation. The iPS cells produced are very similar to embryonic stem cells in morphology, gene and protein expression, epigenetic modification, cell proliferation, embryoid and teratoma production and differentiation.
From June 5438 to October 2007 10, Thompson Laboratories and shinya yamanaka Laboratories reported that human skin fibroblasts could be induced to become pluripotent stem cells almost the same as embryonic stem cells by ips technology.
The difference is that Japanese laboratories still use retrovirus to introduce the combination of four factors, namely Oct3/4, Sox2, c-Myc and Klf4, while Thompson laboratories use lentiviral vectors to introduce the combination of Oct4, Sox2 plus Nanog and LIN28.
These research results have been rated as the second of the top ten scientific and technological breakthroughs in 2007 by American Science magazine.
In 2008, Gee Daley Laboratory of Harvard University used induced cell reprogramming technology to transform skin cells of 10 patients with different genetic diseases into iPS, which will play an important role in establishing disease models and drug screening.
American scientists have also found that under appropriate induction conditions, iPS can differentiate directionally, such as becoming blood cells, and then used to treat diseases.
Another laboratory of Harvard University found that introducing three transcription factors that play an important role in the development of mouse pancreatic exocrine cells can directly transform them into cells very similar to stem cells, and can secrete insulin and effectively lower blood sugar. This shows that a specific tissue cell can be obtained directly by induced reprogramming technology without the step of inducing pluripotent stem cells first.
In 2009, Chinese scientists used iPS cells to cultivate mice-Xiaoxiao June 2008 +2008 10.
The research team led by qi zhou, Institute of Zoology, Chinese Academy of Sciences, and Ceng Fanyi, School of Medicine, Shanghai Jiaotong University showed that iPS cells can be used to obtain viable mice with reproductive capacity, which proved for the first time in the world that iPS cells and embryonic stem cells have similar pluripotency. Scientists say that this study shows that iPS stem cells may become a potential source of treatment for various diseases like embryonic stem cells.
Simple process of preparing ips cells The process of establishing iPS cells mainly includes:
(1) isolation and culture of host cells;
(2) introducing a variety of genes related to pluripotency into host cells through virus-mediated or other means;
(3) The virus-infected cells are planted on the feeder layer cells and cultured in a special culture system for ES cells, and at the same time, corresponding small molecular substances are added to the culture as needed to promote reprogramming;
(4) Identification of iPS cells after the emergence of 4)ES-like clones (cell morphology, epigenetics, differentiation potential in vitro, etc.). ).
The emergence of ips cells has aroused strong repercussions in the fields of stem cell research, epigenetics research and biomedical research, not only because of its importance in basic research, but also because of its bright application prospects.
In basic research, its appearance makes people have a breakthrough new understanding of the regulation mechanism of pluripotency. Cell reprogramming is a complex process, which is not only regulated by intracellular factors, but also by extracellular signal pathways. The research on transcription factors such as Oct4, Sox2, Nanog, etc., which maintain the new ability of cells, is being carried out gradually. Taking iPS cells as an experimental model and manipulating the expression of only a few factors will greatly accelerate the in-depth study of pluripotency regulation mechanism.
In practical application, the method of obtaining iPS cells is relatively simple and stable, and eggs or embryos are not needed. This is more advantageous than other methods in technology and ethics. The establishment of iPS cells has further narrowed the distance between stem cells and clinical disease treatment, and iPS cells have great potential value in cell replacement therapy, pathogenesis research, new drug screening and so on.
In addition, the role of iPS cells in nervous system diseases and cardiovascular diseases. IPS cells have successfully differentiated into neuron cells, glial cells, cardiovascular cells and primordial germ cells in vitro. It has great application value in the treatment of clinical diseases.
Advantages are different from the classical embryonic stem cell technology and somatic cell nuclear transfer technology. iPS technology does not use embryonic cells or egg cells, so there is no ethical problem.
Because of iPS technology, patients can use their own somatic cells to prepare proprietary stem cells, so there will be no problem of immune rejection.
Disadvantages Adding four "reprogramming" genes or replacing defective genes in diseased cells may have side effects that lead to cancer.
Related Research 20 12 10 10 On 8 October, the Karolinska Medical College in Sweden announced that this year's Nobel Prize in Medical Physiology would be awarded to Professor shinya yamanaka of Kyoto University and Dr. john gordon, a British developmental biologist and Cambridge University.
The prize-winning achievement is that Professor shinya yamanaka has cultivated "induced pluripotent stem cells", namely iPS cells, from somatic cells such as skin cells. IPS cells can cultivate all kinds of cells, so Professor shinya yamanaka's invention has opened up a brand-new road for regenerative medicine.
Professor shinya yamanaka published his research results in August 2006. He successfully cultivated iPS cells by injecting four genes into somatic cells extracted from mouse tails. In June 2007, he announced that the experiment on human skin cells was also successful.
Due to its own safety problems, it is estimated that mice developed from iPS cells will not be used for clinical treatment until 20 12 years. In order to obtain safe and practical therapeutic iPS cells with clinical application value, it is necessary to avoid using integrated viruses and carcinogenic foreign genes. According to a series of breakthroughs made by iPS cells in a short time, it can be predicted that iPS cells will surely solve various diseases faced by human beings. However, there are still many areas that need to be broken through and further studied:
(1) To study the regulation mechanism of self-replication, proliferation and differentiation of iPS cells and the mechanism of induced differentiation of iPS cells in vitro;
(2) Fully evaluate the safety of clinical application of iPS cells;
(3) To establish a method for preparing iPS cells without genetic modification (such as reprogramming human cells into iPS cells only with protein or small molecular compounds).
The scientific scandal 20 12 10 iPS cells (induced pluripotent stem cells) produced cardiomyocytes and transplanted them to patients with severe heart disease is a fiction, and Moriguchi, a special researcher at the University Hospital of Tokyo, himself admitted the falsification.