selfrenew

Self-renewal is the process by which stem cells divide to produce new cells that retain the ability to divide and to differentiate into specialized cell types. In many tissues, a pool of stem cells maintains tissue homeostasis across an organism’s life by balancing self-renewal with differentiation. Stem cell divisions can be symmetric, producing two stem cells, or asymmetric, yielding one stem cell and one progenitor cell that will differentiate. The regulation of self-renewal involves intrinsic genetic programs and extrinsic signals from the cellular niche, including signaling pathways such as Wnt, Notch, Hedgehog, and growth factors. Telomere maintenance and metabolic state also influence self-renewal capacity.

Different cell types exhibit self-renewal to varying degrees. Embryonic stem cells and several adult stem cell populations, such as hematopoietic, neural, and intestinal stem cells, possess substantial self-renewal potential, enabling tissue regeneration. In plants, stem cells within meristems also display self-renewal, supporting continual growth and organ formation.

Clinical relevance: aberrant self-renewal is a hallmark of cancer, often mediated by cancer stem cells that can sustain tumor growth and contribute to therapy resistance. Conversely, controlled self-renewal is essential for regenerative medicine, where expandable, undifferentiated stem cells or induced pluripotent stem cells serve as starting material for differentiation into desired lineages.

Measurement and challenges: researchers use lineage tracing, clonal assays, and label-retention experiments to assess self-renewal. Culturing conditions must preserve self-renewal while minimizing differentiation and genetic instability.