Stem cells and the evolving notion of cellular identity

Abstract

Stem cells are but one class of the myriad types of cells within an organism. With potential to self-renew and capacity to differentiate, stem cells play essential roles at multiple stages of development. In the early embryo, pluripotent stem cells represent progenitors for all tissues while later in development, tissue-restricted stem cells give rise to cells with highly specialized functions. As best understood in the blood, skin and gut, stem cells are the seeds that sustain tissue homeostasis and regeneration, while in other tissues like the muscle, liver, kidney and lung, various stem or progenitor cells play facultative roles in tissue repair and response to injury. Here, I will provide a brief perspective on the evolving notion of cellular identity and how reprogramming and transcription factor-mediated conversions of one cell type into another have fundamentally altered our assumptions about the stability of cell identity, with profound long-term implications for biomedical research and regenerative medicine.

Inhibiting Smad2/3 signaling in pluripotent mouse embryonic stem cells enhances endoderm formation by increasing transcriptional priming of lineage‐specifying target genes

“…Pluripotent embryonic stem cells (ESCs) derived from the early embryo offer great potential for regenerative medicine. Realizing this potential will require an understanding of how the balance between pluripotency and cell fate commitment is regulated, a process achieved in vivo by interaction between intercellular signaling pathways and the intrinsic regulatory networks established by each cell's unique developmental history (Daley, 2015). Elucidation of these interdependent processes is critical to achieving differentiation protocols that will allow specific differentiated cell types to be efficiently generated in vitro.…”

Steroid Hormones and the Physiological Regulation of Tissue-Resident Stem Cells: Lessons from the Drosophila Ovary

“…Tissue-resident stem cells have two defining characteristics: they self-renew, maintaining a stem cell pool throughout the life of the organism, and they generate daughter cells that can differentiate into one or more distinct terminal fates [8]. These properties ensure that tissue integrity and cellular diversity are maintained in the face of normal cellular turnover, tissue remodeling, or damage.…”

RNAi-Based Techniques for the Analysis of Gene Function in Drosophila Germline Stem Cells

“…Unlike most specialized cells, which divide to produce identical daughter cells, stem cells are endowed with the property of long-term self-renewal [1]. During cell division, a stem cell retains its unspecialized fate while producing a non-identical daughter destined for differentiation.…”