The haematopoietic stem cell niche at a glance

C Lo Celso, DT Scadden - Journal of cell science, 2011 - journals.biologists.com
Journal of cell science, 2011journals.biologists.com
ARTICLE SERIES: Stem Cells Cell Science at a Glance 3529 dormancy (Trumpp et al.,
2010) and, thereby, maintain homeostasis both in the steady state as well as in response to
injury. HSCs are among the longest studied and utilised somatic stem cells. However, they
cannot yet be maintained and expanded in vitro because a complex and dynamic molecular
crosstalk between HSC and their endogenous microenvironment (or 'niche') directs their
fate. The importance of the stem cell niche in regulating HSC function was first postulated in …
ARTICLE SERIES: Stem Cells Cell Science at a Glance 3529 dormancy (Trumpp et al., 2010) and, thereby, maintain homeostasis both in the steady state as well as in response to injury. HSCs are among the longest studied and utilised somatic stem cells. However, they cannot yet be maintained and expanded in vitro because a complex and dynamic molecular crosstalk between HSC and their endogenous microenvironment (or ‘niche’) directs their fate. The importance of the stem cell niche in regulating HSC function was first postulated in 1978 by Ray Schofield, when observing that the spleen is unable to support HSCs in the same way that bone marrow can (Schofield, 1978). Since then, it has become clear that not only HSCs but all somatic stem cells maintain homeostasis because they sense and respond to the need of an organism for their differentiated progeny as well as to stem cells themselves. The stem cell niche is the functional and anatomical ‘node’that allows integration of signals from the periphery into the appropriate stem cell behaviour. The constantly evolving technological and experimental approaches have provided insights into the nature of the HSC niche, the specific function of different niche components and how perturbations in this highly integrated system are involved in the development of haematopoietic disease. In this Cell Science at a Glance article, we provide an update of the cellular and molecular components of the HSC niche, describe how they adapt in response to specific stimuli, and discuss their potential role in the development of haematopoietic disease. As several controversial observations have led to the most recently proposed niche models and because future studies are likely to further change our views again, we do not present a definitive, detailed portrait of the HSC niche but, instead, integrate currently accepted niche elements and dynamic models to provide an up-to-date overview. Box 1 contains details on the specific nomenclature used in this article. Box 2 contains a brief summary of recent
journals.biologists.com