iPS Cell Reprogramming

Induced pluripotent stem (iPS) cells, are a type of pluripotent stem cell derived from adult somatic cells that have been genetically reprogrammed to an embryonic stem (ES) cell‑like state through the forced expression of genes and factors important for maintaining the defining properties of ES cells.

iPS cells were originally derived from embryonic fibroblasts in mouse and skin fibroblasts in humans. Fibroblasts have been most widely used for reprogramming. Thereafter, other cells, including neural stem cells, keratinocytes, melanocytes, adipose tissue–derived cells, and various blood mononuclear cells, have been successfully used for reprogramming to achieve higher efficiency or to show easier and more convenient accessibility. Advances have occurred in the delivery vectors for reprogramming factors, Oct4, Sox2, Klf4, c‑Myc, Nanog, and Lin28. Initial studies used DNA‑integrating viral vectors such as retrovirus and lentivirus, but later studies demonstrated the usefulness of nonintegrating viral vectors, adenovirus, and nonviral systems with plasmids for reprogramming.