In my view, one of the most impactful events in developmental biology and biomedicine over the past 50 years is the introduction of pluripotency in somatic cells by nuclear reprogramming, creating induced pluripotent stem cells (iPSCs).
The significance of these cells lie in their resemblance to embryonic stem cells (ES cells). ES cells are of great value, but the availability is limited, and the use of them poses certain ethical issues, since they often originate from embryos. The appearance of iPSCs has created great progress in studies that rely on human pluripotent cells. They can be made in larger quantities and originate from somatic cells, solving both issues with availability and ethics of ES cells as well as pluripotent stem cells created by somatic cell nuclear transfer.
iPSCs were first created in 2006 in Japan. Shinya Yamanaka and his group succeeded in producing stem cell-like cells by nuclear reprogramming of somatic cells in vitro using pluripotency associated transcription factors (Oct4, Klf4, Sox2 and c-Myc). In 2012, Shinya Yamanaka and colleague John Gurdon were awarded the Nobel Prize in Physiology and Medicine for their discoveries. Since then the method of reprogramming into pluripotency has significantly improved.
iPSCs have a wide range of applications in research and hold a great potential for future therapeutics.
In developmental studies, they serve as models for human ES cells and the processes these undergo.
Their pluripotency allows them to differentiate into all tissues of the body, so they can serve as model systems for development of both healthy and sick human tissue. By introducing specific mutations, studies of disease development as well as development and screening of potential drugs are also possible.
High hopes exist for their possible therapeutic applications in the future. Autologous cell replacement therapy is valuable as it enhances recovery from trauma and regeneration of damaged tissues. iPSCs also hold great potential for organ transplants. Reprogramming a patient’s somatic cells to pluripotency and differentiating them to grow the cells/organ of interest will end many problems with donor shortage and immune rejection. However, a good deal of research is still necessary before this becomes reality.
All in all, the research made possible by iPSCs has had a great impact on developmental biology and disease studies, and will probably (hopefully) revolutionize therapeutics in the future.