Stem cells and their niches.
A constellation of intrinsic and extrinsic cellular mechanisms regulates the balance of self-renewal and differentiation in all stem cells. Stem cells, their progeny, and elements of their microenvironment make up an anatomical structure that coordinates normal homeostatic production of functional mature cells. Here we discuss the stem cell niche concept, highlight recent progress, and identify important unanswered questions. We focus on three mammalian stem cell systems where large numbers of mature cells must be continuously produced throughout adult life: intestinal epithelium, epidermal structures, and bone marrow.
Moore
Kateri A
KA
Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Princeton, NJ 08544, USA. kamoore@princeton.edu
Lemischka
Ihor R
IR
D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000502:physiology; D002454:Cell Differentiation; D002455:Cell Division; D019070:Cell Lineage; D020405:Dermis / Q000166:cytology / Q000502:physiology; D000078404:Epidermal Cells; D004817:Epidermis / Q000502:physiology; D018859:Hair Follicle / Q000166:cytology*; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000502:physiology*; D006706:Homeostasis; D007413:Intestinal Mucosa / Q000166:cytology*; D008648:Mesoderm / Q000166:cytology / Q000502:physiology; D039902:Multipotent Stem Cells / Q000166:cytology / Q000502:physiology; D010006:Osteoblasts / Q000502:physiology; D015398:Signal Transduction; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology* / Q000502:physiology*