The first successful nonviral iPSCs were produced from mature embryonic fibroblast cells transfected with two plasmid constructs; the first plasmid encodes for the c-Myc, while the second plasmid a polycistronic vector encodes the four defined reprogramming factors.Human and murine iPSCs have been successfully created using nonintegrating viral vectors such as adenovirus.To generate iPSCs free of vector integration into chromosomes, the pluripotency marker genes can be directly and transiently delivered into the somatic cells using cytoplasmic RNA, episomal (self-replicating and selectable vectors),Mouse and human fibroblasts have been successfully reprogrammed by a direct transfer of the recombinant reprogramming proteins in purified formsTo overcome these issues, the introduction of either synthetic RNA or messenger RNA (mRNA) encoding the reprogramming factors may be a powerful platform for creating integration-free pluripotent cells.
In 2006, Takahashi and Yamanaka selected twenty-four candidate Next, Takahashi tried to insert into a fibroblast cell multiple The next experiments aimed to identify specific factors responsible for the generation of iPS cells.
Differentiated cells can be reprogrammed to an embryonic-like state by transfer of nuclear contents into oocytes or by fusion with embryonic stem (ES) cells. Yamanaka's research has “opened a new door and the world's scientists have set forth on a long journey of exploration, hoping to find our cells’ true potential.”In 2013, iPS cells were used to generate a human vascularized and functional liver in mice in Japan. Moreover, in 2007, Yamanaka and his colleagues found iPS cells with germ line transmission (via selecting for Oct4 or Nanog gene). Moreover, in 2014, the first clinical trial using a patient’s own iPSCs opened the door for direct therapeutic applications of the technology.
In 2006, Kazutoshi Takahashi and Shinya Yamanaka reprogrammed mice fibroblast cells, which can produce only other fibroblast cells, to become pluripotent stem cells, which have the capacity to produce many different types of cells.Takahashi and Yamanaka also experimented with human cell cultures in 2007.
Transdifferentiation experiments were carried out. Induced Pluripotent Stem (iPS) Cells were developed in 2007 by Shinya Yamanaka of Kyoto University. The ability to generate patient-specific iPSCs offers an invaluable reservoir of pluripotent cells, which could be genetically engineered and differentiated into target cells to treat various genetic and degenerative diseases once transplanted, hence counteracting the risk of graft versus host disease. Remarkable achievements have been made in iPSC-based clinical trials for the past 13 years. Critically, it also avoids the risk of cancerous cells forming from stem cell intermediates.
However, stem cells with limited potency (adult stem cells) remain in bone marrow, intestine, skin etc. Then the scientists have to activate the genes involved in pluripotency, and finally, tissue-specific genes must be repressed to prevent the stem cells from developing into more mature organ cells. Stem cells can replace diseased or lost cells in degenerative disorders and they are less prone to immune rejection.
Next, the scientists injected the candidate factors into mouse skin cells to test whether the factors could induce pluripotency. The prevalent view during the early 20th century was that mature cells were permanently locked into the differentiated state and cannot return to a fully immature, pluripotent stem cell state.
These laboratory-grown stem cells are pluripotent – they can make any type of cell in the body - and are called induced pluripotent stem cells, or iPS cells.
iPSCs have been shown to have regenerative properties and have also been shown to be similar in characteristics and abilities to ESCs (Takahashi and Yamanaka, 2006).