12/3/2023 0 Comments Stem cell flow chart![]() ![]() These findings introduced the two defining criteria of stem cells i.e. Analysis of these colonies revealed that a very small sub-population of the donor BM cells possessed two remarkable properties: (1) the ability to generate multiple types of myeloerythroid cells, and (2) the ability to self-replicate 1. Ten days after transplanting limiting number of syngenic bone marrow (BM) cells into recipient mice, they observed cellular colonies that formed in the spleens of recipient mice. The “stem cell” concept was first proposed by Till and McCulloch following their pioneering studies of the blood system regeneration in vivo. In this review, we focus on the outlined conundrum, and discuss what is currently known of the regulatory events that govern the ability of HSCs to generate many billions of mature blood cells while at the same time maintaining an adequate pool of HSCs for the entire life of the species. These intriguing features of mammalian hematopoiesis have fueled extensive investigation of the system over the last several decades. when HSC differentiation into committed progenitors is not accompanied by the typical loss of self-renewal capacity, or HSC derived progenitors fail to fully differentiate into mature blood cells, and may enter a preleukemic progression. The importance of this balance is underscored by the numerous examples where aberrant HSC development causes severe disease e.g. These two facts present an interesting conundrum: how dose the organism achieve a balance whereby an adequate pool of HSCs is maintained for the life of the organism, while at the same time HSCs consistently meet the organism’s enormous demand for continuous replenishment of mature blood cells, most of which are short-lived. While mature blood cells are produced at a rate of more than one million cells per second in the adult human, most of the hematopoietic stem cells (HSCs) from which they are derived cycle very infrequently and primarily reside in the G 0 phase of the cell cycle under homeostatic conditions. In this review, we focus on the hierarchical structure of the hematopoietic system, the current understanding of microenvironment and molecular cues regulating self-renewal and differentiation of adult HSC, and the currently emerging systems approaches to understand HSC biology. Thus, understanding the mechanisms of self-renewal and differentiation of HSC has been a central issue. Since mature blood cells are predominantly short lived, HSC continuously provide more differentiated progenitors while properly maintaining the HSC pool size properly throughout life by precisely balancing self-renewal and differentiation. Self-renewal is the ability to give rise to HSC itself without differentiation. Multi-potency is the ability to differentiate into all functional blood cells. Within the system, only HSC possess the ability of both multi-potency and self-renewal. The mammalian blood system, containing more than ten distinct mature cell types, stands on one specific cell type, hematopoietic stem cell (HSC).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |