iPSCs

Induced pluripotent stem cells (iPSCs) are a type of pluripotent stem cell derived from adult somatic cells that have been genetically reprogrammed to an embryonic stem cell–like state. iPSCs can self-renew indefinitely in culture and differentiate into cells of all three germ layers: ectoderm, mesoderm, and endoderm, enabling potential applications in research and medicine.

iPSCs were first reported by Shinya Yamanaka and colleagues in 2006, who reprogrammed mouse cells using four transcription factors—Oct4, Sox2, Klf4, and c-Myc—later demonstrated in human cells. Since then, reprogramming methods have expanded beyond integrating viral delivery to include non-integrating approaches such as Sendai virus, episomal plasmids, mRNA, and small molecules, reducing or eliminating genetic modification of the genome.

Because iPSCs can be generated from a person's own cells, they offer the promise of patient-specific cell replacement therapies with reduced risk of immune rejection. They also enable disease modeling, drug screening, and toxicology testing using patient-derived cells. However, challenges remain: iPSCs can harbor genetic and epigenetic abnormalities, reprogramming may carry tumorigenic risks, and differentiation protocols must be tightly controlled to obtain pure, functional cell types. Residual epigenetic memory from the donor cell can influence behavior of derived cells, and there is ongoing work to improve efficiency and safety of reprogramming and differentiation.

In research and some clinical contexts, iPSCs are used to model developmental processes, study disease mechanisms, and screen therapeutics, with regulatory and safety considerations guiding any prospective therapeutic applications.