dedifferensiering

Dedifferensiering, or dedifferentiation, is the process by which specialized, mature cells revert to a less specialized, proliferative state. This cellular plasticity can enable tissue regrowth and is observed in both plants and animals. Dedifferentiation is distinct from reprogramming to pluripotency in vitro and from direct transdifferentiation into another mature cell type.

In plants, dedifferentiation is common and central to growth and wound repair. Differentiated cells may re-enter the cell cycle, form callus tissue, and later redifferentiate into several tissue types. The process is controlled by hormones such as auxin and cytokinin and involves epigenetic remodeling.

In animals, dedifferentiation occurs during regenerative processes in some vertebrates, notably urodele amphibians and certain fish, where mature cells revert to progenitors to form a blastema and regrow limbs or fins. In mammals, dedifferentiation is more limited but has been reported in liver and skin regeneration and in cancer, where cells may gain stem-like traits.

Mechanistically, dedifferentiation involves changes in gene expression, chromatin state, and signaling pathways such as Wnt, Notch, TGF-beta, and Hippo. It can be partial or complete and may be reversible as healing proceeds.

Context and significance: Understanding dedifferentiation informs regenerative medicine and oncology, revealing how developmental programs can be reactivated for healing or, conversely, how cellular plasticity can drive tumor progression.