%0 Journal Article
%T Hematopoietic Stem Cell Development, Niches, and Signaling Pathways
%A Kamonnaree Chotinantakul
%A Wilairat Leeanansaksiri
%J Bone Marrow Research
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/270425
%X Hematopoietic stem cells (HSCs) play a key role in hematopoietic system that functions mainly in homeostasis and immune response. HSCs transplantation has been applied for the treatment of several diseases. However, HSCs persist in the small quantity within the body, mostly in the quiescent state. Understanding the basic knowledge of HSCs is useful for stem cell biology research and therapeutic medicine development. Thus, this paper emphasizes on HSC origin, source, development, the niche, and signaling pathways which support HSC maintenance and balance between self-renewal and proliferation which will be useful for the advancement of HSC expansion and transplantation in the future. 1. Introduction Hematopoietic stem cells (HSC) are adult stem cells that contain the potentiality in self-renew and differentiation into specialized blood cells that function in some biological activities: control homeostasis balance, immune function, and response to microorganisms and inflammation. HSCs can also differentiate into other specialized cell or so called plasticity such as adipocytes [1], cardiomyocytes [2], endothelial cells [3], fibroblasts/myofibroblasts [4], liver cells [5, 6], osteochondrocytes [7, 8], and pancreatic cells [9]. Most HSCs are in quiescent state within the niches that maintain HSC pool and will respond to the signals after the balance of blood cells or HSC pool is disturbed from either intrinsic or extrinsic stimuli. In addition, HSCs have been studied extensively, especially, for the therapeutic purposes in the treatment of blood diseases, inherited blood disorders, and autoimmune diseases. Nonetheless, advanced development in this field needs knowledge in the biological studies as a background in performing strategy and maintaining of HSCs. Thus, HSC source, origin, niches for HSC pool, and signaling pathways, essential for the regulation of HSCs, will be discussed in this review. 2. HSCs Origin and Development In the hematopoietic system, the discovery of HSCs has shed the light on stem cell biology studies including connection to other adult stem cells through the basic concepts of differentiation, multipotentiality, and self-renewal. In the early period of those discoveries, lethally irradiated animals were found to be rescued by spleen cells or marrow cells [17, 18]. After mouse bone marrow cells were transplanted into irradiated mice, the clonogenic mixed colony of hematopoietic cells (often composed of granulocyte/megakaryocyte and erythroid precursors) were formed within the spleen, which these colonies were then termed
%U http://www.hindawi.com/journals/bmr/2012/270425/