Stem cell niche

The functions of the CXCL12—CXCR4 axis in maintaining the stem cell pool might include chemo-localization to specialized stem cell niches as well as maintenance of mitotic quiescence characteristic of stem cell populations. Bone marrow... 

Fig. 1. Surface phenotype of HSPCs. Primitive HSPCs have the phenotype of c-KitThy-ll0WLin CD34+CD33 in humans, and the mouse counterparts have the phenotype of c-KifThy-llowLin Sca-l+. Primitive HSPCs express CXCR4 as the major chemokine receptor and various adhesion molecules such as VLA-4, VLA-5, LFA-1, P-selectin glycoprotein ligand-1 (PSGL-1), and CD44 for migration to the stem cell niche.

Taichman RS. Blood and bone two tissues whose fates are intertwined to create the hematopoietic stem cell niche. Blood. 2005 105 2631-2639. 

Scadden D.T. (2006) The stem-cell niche as an entity of action. Nature. 441, 1075-9. Trosko J.E., Chang C.C. (1989) Stem cell theory of carcinogenesis. Toxicol Lett. 49, 283-95. 

Lim, D.A., Huang, Y.C., Alvarez-Buylla, A. (2007) The adult neural stem cell niche lessons for future neural cell replacement strategies. Neurosurg Clin N Am 18, 81-92, ix. 

Scadden, D.T. (2006) The stem-cell niche as an entity of action. Nature 441, 1075-9. 

Calvi LM, Adams GB, Weibrecht KW, Weber JM, Olson DP, Knight MC, Martin RP, Schipani E, Divieti P, Bringhurst FR, Milner LA, Kronenberg HM, Scadden DT (2003), Osteoblastic cells regulate the haematopoietic stem cell niche, Nature 425 841-846. 

Kai T, Spradling A (2003), An empty Drosophila stem cell niche reactivates the proliferation of ectopic cells, Proc. Natl Acad. Sci. USA 100 4633-4638. 

Zhang J, Niu C, Ye L, Huang H, He X, Tong WG, Ross J, Haug J, Johnson T, Feng JQ, Harris S, Wiedemann LM, Mishina Y, Li L (2003), Identification of the haematopoietic stem cell niche and control of the niche size, Nature 425 836-841. 

Machold R, Hayaslii S, Rutlin M, Muzumdai MD, Nery S, Corbin JG, Giitli-Linde A, Dellovade T, Porter JA, Rubin LL, Dudek H, McMalion AP, Fishell G (2003) Sonic hedgehog is required for progenitor cell maintenance in telencephalic stem cell niches. Neuron 39 937-950. 

Mills, J. C., and J. 1. Gordon. 2001. The intestinal stem cell niche there grows the neighborhood. Proc. Nat l. Acad. Sci. USA 98 12334-12336. 

It has been shown that stem cell self-renewal and differentiation rates are influenced by their microenvironment, termed stem cell niche [107, 108]. The stem cell niche consists of the following components (1) extracellular matrix [109] (2) biochemical factors including cell-cell and cell-mahix interactions, localized soluble stimuli and gradients of soluble factors like growth factors and glucose concentration [ 110,111] ... 

Identifying the niches of stem cells in vivo and the requirements for stem cell viability and repopulation is essential for futme therapies in regenerative medicine, possibly by activating stem cells in situ. In Drosophila, tluee cell types act as germ line stem cell niche. 

Borthwick D W, Shahbazian M, Krantz Q T, et al. (2001). Evidence for stem-cell niches in the tracheal epithelium. Am. J. Respir. Cell. Mol. Biol. 24 662-670. 

There are several connections between hypoxia and control of normal stem cell biology. For example, hematopoietic stem cells (HSCs) are enriched in hypoxic regions of bone [133], expansion of HSCs ex vivo is more efficient under hypoxic conditions [134], and neurosphere formation is also enhanced at 3% O2 [135]. In addition, it has been suggested that CSCs exist in a hypoxic environment and that hypoxia stimulates expansion of CSCs, as reviewed in [16]. For example, the local microenvironment of the stem cell niche may influence the ability of CSCs to... 

Normal SCs are found to harbor in a specialized microenvironment called the stem cell niche , which contains capillaries, vascular endothelial cells, pericytes, and the fibrous proteins of the extracellular matrix. Other stromal cells, immune cells, and nerves may also be present in the niche [45]. Stimuli from the niche as well as signals from SCs themselves and from outside of niche, together, establish a regulatory network to balance between SC self-renewal and differentiation [46]. Under physiological conditions, the niche provides a tight control over proliferation, typically maintaining cells in GO and/or balancing... 

Tumbar T, Guasch G, Greco V et al. (2004) Defining the epithelial stem cell niche in skin. Science 303 359-363... 

Li H, Chen X, Calhoun-Davis T et al. (2008) PC3 human prostate carcinoma cell holoclones contain self-renewing tumor-initiating cells. Cancer Res 68 1820-1825 Baguley BC (2006) Tumor stem cell niches a new functional framework for the action of anticancer drugs. Recent Patents Anticancer Drug Discov 1 121-127 Trumpp A, Wiestler OD (2008) Mechanisms of Disease cancer stem cells - targeting the evil twin. Nat Clin Pract Oncol 5 337-347... 

Li L, Xie T (2005) Stem cell niche structure and function. Annu Rev Cell Dev Biol 21 605-631 Sipkins DA, Wei X, Wu J et al. (2005) In vivo imaging of specialized bone marrow endothelial microdomains for tumour engraftment. Nature 435 969-973 Calabrese C, Poppleton H, Kocak M et al. (2007) A perivascular niche for brain tumor stem cells. Cancer Cell 11 69-82... 

Wilson A, Trumpp A (2006) Bone-marrow haematopoietic-stem-cell niches. Nat Rev Immunol 6 93-106... 

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