scholarly journals Regulation of the expression of the hematopoietic stem cell antigen CD34: role of c-myb.

1994 ◽  
Vol 179 (3) ◽  
pp. 1023-1028 ◽  
Author(s):  
P Melotti ◽  
D H Ku ◽  
B Calabretta
Keyword(s):  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Surface Membrane ◽  
Specific Interaction ◽  
Constitutive Expression ◽  
Hematopoietic Stem ◽  
Cell Antigen ◽  
Cd34 Antigen ◽  
Flanking Region

The CD34 antigen defines a subset of hematopoietic progenitor cells with self-renewal capacity and the ability to reconstitute hematopoiesis in irradiated primates and marrow-ablated humans, but its function remains unknown. The c-myb protooncogene plays a fundamental role in hematopoiesis, most likely via its transcriptional regulator function. We report that c-myb protein transactivates the CD34 promoter via specific interaction with multiple Myb binding sites in the 5' flanking region of the gene and induces expression of the endogenous CD34 mRNA in rodent fibroblasts. Also, constitutive expression of c-myb in CD34-negative human glioblastoma cells induces expression of CD34 mRNA and synthesis of the surface membrane antigen. These data directly demonstrate that c-myb regulates the expression of the hematopoietic stem cell antigen CD34 and raise the possibility that c-myb regulates hematopoiesis inducing a cascade of differentiation-related events.

Endothelial and Circulating Progenitor Cells in Hematological Diseases and Allogeneic Hematopoietic Stem Cell Transplantation

2018 ◽  
Vol 25 (35) ◽  
pp. 4535-4544 ◽  
Author(s):  
Annalisa Ruggeri ◽  
Annalisa Paviglianiti ◽  
Fernanda Volt ◽  
Chantal Kenzey ◽  
Hanadi Rafii ◽  
...  
Keyword(s):  
Stem Cell ◽  
Hematopoietic Stem Cell Transplantation ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Hematopoietic Stem Cell ◽  
Peripheral Blood ◽  
Circulating Endothelial Cells ◽  
Hematopoietic Stem ◽  
Hematological Diseases

Background: Circulating endothelial cells (CECs), originated form endothelial progenitors (EPCs) are mature cells not associated with vessel walls and detached from the endothelium. Normally, they are present in insignificant amounts in the peripheral blood of healthy individuals. On the other hand, elevated CECs and EPCs levels have been reported in the peripheral blood of patients with different types of cancers and other diseases. Objective: This review aims to provide an overview on the characterization of CECs and EPCs, to describe isolation methods and to identify the potential role of these cells in hematological diseases and hematopoietic stem cell transplantation. Methods: We performed a detailed search of peer-reviewed literature using keywords related to CECs, EPCs, allogeneic hematopoietic stem cell transplantation, and hematological diseases (hemoglobinopathies, hodgkin and non-hodgkin lymphoma, acute leukemia, myeloproliferative syndromes, chronic lymphocytic leukemia). Results: CECs and EPCs are potential biomarkers for several clinical conditions involving endothelial turnover and remodeling, such as in hematological diseases. These cells may be involved in disease progression and in the neoplastic process. Moreover, CECs and EPCs are probably involved in endothelial damage which is a marker of several complications following allogeneic hematopoietic stem cell transplantation. Conclusion: This review provides information about the role of CECs and EPCs in hematological malignancies and shows their implication in predicting disease activity as well as improving HSCT outcomes.

scholarly journals Crosstalk between NOTCH and AKT signaling during murine megakaryocyte lineage specification

Blood ◽  
2011 ◽  
Vol 118 (5) ◽  
pp. 1264-1273 ◽  
Author(s):  
Melanie G. Cornejo ◽  
Vinciane Mabialah ◽  
Stephen M. Sykes ◽  
Tulasi Khandan ◽  
Cristina Lo Celso ◽  
...  
Keyword(s):  
Stem Cell ◽  
Notch Signaling ◽  
Signaling Pathway ◽  
Hematopoietic Stem Cell ◽  
Stem Cell Differentiation ◽  
Notch Signaling Pathway ◽  
Developmental Pathways ◽  
Lineage Specification ◽  
Hematopoietic Stem

Abstract The NOTCH signaling pathway is implicated in a broad range of developmental processes, including cell fate decisions. However, the molecular basis for its role at the different steps of stem cell lineage commitment is unclear. We recently identified the NOTCH signaling pathway as a positive regulator of megakaryocyte lineage specification during hematopoiesis, but the developmental pathways that allow hematopoietic stem cell differentiation into the erythro-megakaryocytic lineages remain controversial. Here, we investigated the role of downstream mediators of NOTCH during megakaryopoiesis and report crosstalk between the NOTCH and PI3K/AKT pathways. We demonstrate the inhibitory role of phosphatase with tensin homolog and Forkhead Box class O factors on megakaryopoiesis in vivo. Finally, our data annotate developmental mechanisms in the hematopoietic system that enable a decision to be made either at the hematopoietic stem cell or the committed progenitor level to commit to the megakaryocyte lineage, supporting the existence of 2 distinct developmental pathways.

scholarly journals Osteoclasts promote the formation of hematopoietic stem cell niches in the bone marrow

2012 ◽  
Vol 209 (3) ◽  
pp. 537-549 ◽  
Author(s):  
Anna Mansour ◽  
Grazia Abou-Ezzi ◽  
Ewa Sitnicka ◽  
Sten Eirik W. Jacobsen ◽  
Abdelilah Wakkach ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Endochondral Ossification ◽  
Osteoblastic Differentiation ◽  
Hematopoietic Stem ◽  
Mesenchymal Progenitors ◽  
Hsc Niche ◽  
Niche Formation

Formation of the hematopoietic stem cell (HSC) niche in bone marrow (BM) is tightly associated with endochondral ossification, but little is known about the mechanisms involved. We used the oc/oc mouse, a mouse model with impaired endochondral ossification caused by a loss of osteoclast (OCL) activity, to investigate the role of osteoblasts (OBLs) and OCLs in the HSC niche formation. The absence of OCL activity resulted in a defective HSC niche associated with an increased proportion of mesenchymal progenitors but reduced osteoblastic differentiation, leading to impaired HSC homing to the BM. Restoration of OCL activity reversed the defect in HSC niche formation. Our data demonstrate that OBLs are required for establishing HSC niches and that osteoblastic development is induced by OCLs. These findings broaden our knowledge of the HSC niche formation, which is critical for understanding normal and pathological hematopoiesis.

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