Pluripotent

Pluripotent describes a cellular state in which a cell has the capacity to differentiate into cell types representing all three germ layers—ectoderm, mesoderm, and endoderm—giving rise to tissues such as neurons, muscle, and liver. Pluripotent cells can form nearly all tissues of the body but typically cannot develop into extraembryonic structures such as the placenta. The term is central to stem cell biology and developmental biology. Prominent sources of pluripotent cells are embryonic stem cells (ESCs), derived from the inner cell mass of the blastocyst, and induced pluripotent stem cells (iPSCs), which are generated by reprogramming adult cells to an embryonic-like state.

Pluripotent cells are contrasted with totipotent cells, which can form all embryonic and extraembryonic tissues (including the placenta), and multipotent cells, which are restricted to a limited set of cell lineages, such as hematopoietic or mesenchymal lineages.

Key tests of pluripotency include expression of core transcription factors such as Oct4, Nanog, and Sox2; the ability to differentiate into cell types from all three germ layers in vitro (for example, through embryoid body formation); and in vivo tests such as teratoma formation containing tissues from endoderm, mesoderm, and ectoderm. In some species, contribution to chimerism and germline transmission is assessed. iPSCs are generated by reprogramming somatic cells with factors such as Oct4, Sox2, Klf4, and c-Myc; alternative methods seek to reduce genetic risk by using non-integrating or fewer-factor approaches.

Applications of pluripotent cells include modeling development and disease, drug screening, and regenerative medicine. Pluripotent stem cell technologies hold promise for personalized therapies, but challenges remain, including tumorigenicity risk, genetic and epigenetic abnormalities, immune compatibility, and ethical and regulatory considerations surrounding embryo-derived cells.