Induced pluripotent stem cells (iPS cells or iPSCs) are laboratory-made pluripotent stem cells that are produced using adult cells. They are derived from somatic cells by reprogramming artificially and turning on the expression of specific pluripotency genes. The reprogramming is achieved using different techniques with varying efficiencies. The iPSC technology was first discovered in 2006 by Shinya Yamanaka’s lab in Kyoto, Japan. He and his team introduced four specific genes encoding transcription factors and converted adult cells into pluripotent stem cells.
Pluripotent stem cells have several applications in regenerative medicine. They are capable of propagating indefinitely and differentiate into other cell types such as neurons, cardiac cells, pancreatic cells, and liver cells. Naturally occurring pluripotent stem cells are derived from early-stage pre-implanting embryos. These cells are referred to as embryonic stem cells (ESCs) and they can differentiate into all the different types of adult cells in our body. However, to produce ESCs, it becomes necessary to destroy or manipulate the embryos, which is a concern for human ethics.
Therefore, different methods are being used to induce the reprogramming of somatic cells. Initially, scientists used retro or lentiviral transfections to induce the expression of oncogenes into the somatic cells following viral incorporation into the host cell’s genome. Later on, researchers used adenoviral vectors to avoid viral incorporation into the host genome. Unfortunately, the gene expression induced by adenoviral vectors was not maintained long-term in transduced cells, reducing their pluripotent longevity.
Then, expression plasmids alone were used to induce pluripotency genes in somatic cells, but production of iPS colonies was extremely inefficient using this method. Currently, the modified RNA reprogramming method proves to be the safest and most efficient method to reprogram adult cells and stimulate subsequent differentiation into the desired cell product for ultimate therapeutic use. Today, the field of cellular reprogramming is undergoing changes rapidly, and adaptation of techniques developed for other species will likely prove useful to enhance the induction of pluripotency in somatic cells.
Today, iPSCs are being explored for applications related to basic research, drug screening, toxicological studies, disease modeling, cell therapy, personalized medicine, “clean meat” production, and beyond. The somatic cells used for reprogramming commonly include skin cells and blood cells. iPSCs are also leveraged by scientists to learn more about disease onset and progression, as well as to develop and test new drugs and therapies.
The discovery of iPSC has not only favorably transformed the field of drug discovery, toxicity testing and in-a-dish disease modeling, but also powerfully impacted the field of cell and gene therapy. Understandably, the ability of iPSCs to multiply in vitro and then get differentiated into specialized cells makes iPSCs an ideal source of cells for curative cell replacement therapies.
Today, there are 123 ongoing clinical trials are using iPSC-derived cells for various applications. The majority of them do not involve the transplant of iPSCs into humans, but rather involve the creation and evaluation of iPSC lines for clinical purposes. Within these trials, iPSC lines are created from specific patient populations to determine if these cell lines could be a good model for a disease of interest. Only a select few of these trials are administering iPSC-derived cell therapeutics to human patients.
To learn more about this exciting market, view the “Global Induced Pluripotent Stem Cell (iPS Cell) Industry Report – Market Size, Trends, and Forecasts.”
