Parthenogenetic Activation-Induced Pluripotent Stem Cells and Potential Applications

Abstract

Parthenogenesis is the process by which an egg can develop into an embryo without fertilization. Parthenogenesis can be induced by artificial activation of an egg in mammals. Parthenogenetic embryos typically fail to develop past mid-gestation, mostly due to insufficient placental development. Therefore they should not be considered as living embryos. However, parthenogenetic embryonic stem (pES) cells can be generated from parthenogenetic embryos. While aberrant genomic imprinting limits development of parthenogenetic embryos, genomic imprinting undergoes reprogramming during isolation and culture of pES cells enabling pES cells developmental pluripotency and extensive differentiation capacity, similar to ES cells. Indeed, pES cells also are designated as parthenogenetic activation-induced pluripotent stem cells (paiPS). pES cells proliferate indefinitely and show genomic stability with minimal tumorigenesis, so they hold great promise for stem cell therapy. Damaged tissues and degenerative diseases could be treated by pES cells derived from patients’ own eggs, or from immunocompatible, banked pES cells. Presumably their derivation from a non viable embryo source would raise fewer ethical concerns than ES cells derived from embryos. Also, spare eggs are readily available from fertility clinics or can be retrieved from patients anticipating need for pES cell therapy. Patients facing radiation or chemo-therapy could bank eggs to preserve their fertility and also produce pES cells for potential cell therapy. This review focuses on the critical step for generation of pES, oocyte activation, reviews the mechanisms of genomic imprinting underlying pluripotency, provides an overview of potential applications of pES for clinical therapeutics, as well as potential drawbacks of pES cells and strategies to overcome those challenges.KeywordsHuman Embryonic Stem CellImprint GeneInner Cell MassPaternal GenomeOocyte ActivationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.