Linheng Li

..A large number of genes that were differentially expressed by enriched populations of HSCs and MPP cells were identified. These included transcription factors, signaling molecules, and previously unknown genes...

..We hope this examination of the interaction between stem cells and their niche will enhance understanding of the process of cancer development, invasiveness, and metastasis and reveal possible targets for cancer treatment...

..We hope this comparative summary defines the basic elements of the stem cell niche, providing guiding principles for identification of the niche in other systems and pointing to areas for future studies...

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..This study provides the first in vivo evidence that FGF signaling facilitates postinjury recovery of the mouse hematopoietic system by promoting proliferation and facilitating mobilization of HSPCs...

..Their expression profile and lower cell-cycle entry rate suggest N-cadherin(int) cells are being held in reserve. Thus, differential N-cadherin expression reflects functional distinctions between two HSC subpopulations...

..We show for the first time that activation of either single pathway is insufficient to expand primitive HSCs, but in combination, both pathways drive self-renewal and expansion of HSCs with long-term functional capacity...

..Our observations show that intestinal polyposis is initiated by PTEN-deficient ISCs that undergo excessive proliferation driven by Akt activation and nuclear localization of beta-catenin...

..Subsequently, PTEN, through phosphatidyl inositol 3-kinase-Akt, inhibits the activity of beta-catenin, the convergence point of the BMP and Wnt signaling pathways...

..Thus, in contrast to central marrow, the endosteum formed a special zone, which normally maintains HSCs but promotes their expansion in response to bone marrow damage...

..Finally, we review current findings regarding the roles of Wnt, bone morphogenic protein, PtdIns(3,4,5) kinase, and Notch pathways within the intestine...

..Use of tissue specific Cre mice will allow this model to be used to conditionally and inducibly overexpress Runx2 in different tissues and provide a means to study the post-natal tissue- and cell context-dependent functions of Runx2...

..Here, we summarize these findings and propose that quiescent and active stem cell populations have separate but cooperative functional roles...

..Knowledge of the basic features of the HSC niches, including physical location, cell type and various signaling pathways, should provide insights into other stem-cell systems and benefit clinical applications...

..Taken together, our findings demonstrate that noncanonical Wnt signaling maintains quiescent long-term HSCs through Fmi and Fz8 interaction in the niche...

..2007a, 2007b) demonstrate in mice that alterations in the niche for hematopoietic stem cells lead to the development of myeloproliferative disease...

..Thus, PTEN has essential roles in restricting the activation of HSCs, in lineage fate determination, and in the prevention of leukaemogenesis...

..Our work provided more evidence to demonstrate the essential function of the niche in maintenance of stem cells and showed that multiple signals are required to maintain a balanced control of stem cell self-renewal...

..Finally, we provide a basic protocol for the serial-dilution assay, a quantitative assay for HSCs, from which individual researchers can construct their own customized protocols utilizing the guidelines discussed...

..In this review, we describe and discuss components of noncanonical Wnt signaling, diseases caused by deregulation of the signaling, regulation of adult stem cells by the signaling, and implications in cancer biology...

..Matsuoka and colleagues (pp. 986-991) have further illustrated this theme by demonstrating that inactivation of the tumor suppressor Fbxw7 leads to HSC depletion by active cell cycling and the initiation of leukemia...

..We show that the anti-pbeta-catenin-S552 antibody may be useful in diagnosing and monitoring the progression of or response to therapy of MALT lymphoma...

..Many of the discoveries described herein may contribute to future clinical treatments for hematopoietic and bone-related disorders, including cancer...

..Novel types of stem cells and niches were also reported and new findings that clarify our understanding of the molecular mechanisms that regulate and maintain stem cells were presented...

..However, a recent study (Naveiras et al., 2009. Nature 460, 259-263) shows that adipocytes are microenvironmental components that suppress hematopoiesis under homeostatic and especially stressed conditions...

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..Understanding the interaction of different signaling pathways in the context of the hematopoietic stem cell niche is essential for increasing their therapeutic potential...

..However, if stem cell discoveries are to be fully utilized in clinical transplant medicine, aseptic instrument configurations must be developed. For this purpose, we have designed a disposable sterile fluid handling system...

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..We conclude that SNO cells lining the bone surface function as a key component of the niche to support HSCs, and that BMP signalling through BMPRIA controls the number of HSCs by regulating niche size...

..Thus, BMP signaling may control the duplication of intestinal stem cells, thereby preventing crypt fission and the subsequent increase in crypt number...

..These data support the hypothesis that stem cells possess a wide-open chromatin structure to maintain their multipotentiality, which is progressively quenched as they go down a particular pathway of differentiation...

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..Our data show that BMP signaling through Bmpr1a suppresses tumorigenesis at gastric epithelial junctional zones that are distinct from the adjacent gastric epithelium in both cellular differentiation and proliferation...

..This is the first report to show that HSC can differentiate into renal tubular cells after I/R injury. Because of their availability, HSC may be useful for cell replacement therapy of acute renal failure...

..These data imply that hypothermia modifies signaling pathways for apoptosis and suggest possible mechanisms for hypothermia-induced myocardial protection...