Differential expression of endoglin on fetal and adult hematopoietic cells in human bone marrow
Department of Medicine, University of Alabama at Birmingham 35294, USA. The Journal of Immunology
(Impact Factor: 4.92).
Endoglin, a glycoprotein that is expressed by human endothelial cells, binds TGF-beta 1 and -beta 3 with high affinity. It was originally identified with the 44G4 mAb that was produced against a human pre-B cell line. We now report that another anti-pre-B cell mAb, 29-G8, reacts with pro-B and pre-B leukemic cells, but not with mature B and T cells, and recognizes a different epitope of endoglin. The 29-G8 mAb bound specifically to recombinant endoglin and immunoprecipitated a phosphorylated homodimeric glycoprotein with subunits of M(r) 95,000 from the 697 pre-B cell line. This new Ab removed all of the molecules identified by the prototypic 44G4 anti-endoglin Ab, but the reverse was not true. A subpopulation of 29-G8+ endoglin molecules on this pre-B cell line was unreactive with the 44G4 mAb, thus suggesting that these anti-endoglin Abs see different epitopes that may discriminate different species of endoglin molecules. Flow cytometric analysis with the 29-G8 mAb revealed two endoglin-positive subpopulations in fetal bone marrow: early B-lineage precursor cells (CD19+ and CD34+), and proerythroblasts (CD71+ and glycophorin A+). In adult bone marrow, only the proerythroblast subpopulation was observed. Stromal cells derived from fetal bone marrow also reacted strongly with the 29-G8 and 44G4 Abs, and these cells responded with enhanced proliferation after stimulation with either TGF-beta 1 or the anti-endoglin Abs. Thus, endoglin, a specialized component of the TGF-beta receptor system, may play a physiologic role in the stromal-hemopoietic cell interactions occurring during development.
Available from: Paula Laranjeira
- "As previously described by Matarraz and colleagues, the phenotypic profile of CD34+ B cell precursors is CD34 int /CD45 int/dim /HLA-DR hi /cyMPO -/nTdT int /CD117 -and these cells present the lowest SSC and FSC of all CD34+ subpopulations (Lochem et al., 2004; Matarraz et al., 2008); the CD34+ neutrophil precursors present CD34 hi /CD45 int/dim /HLA- DR hi /cyMPO int/hi /nTdT -/CD117 hi , along with the highest values for SSC and FSC of all CD34+ subsets; the CD34+ plasmacytoid dendritic cell precursors are identified based on the expression of CD34 + /CD123 hi/int /HLA-DR hi ; CD34+ monocytic precursors display CD34+/HLA-DR hi /CD64 hi /CD45 hi /CD117 -immunophenotype; basophil precursors are described as being CD34 + /CD123 int/hi /HLA-DR -/+ ; and CD34+ mast cell precursors are CD34+/CD117 hi /HLA-DR -/int (Matarraz et al., 2008). Finally, CD34+ erythroid precursors are characterized by CD34 + /CD36 + /CD64 -/CD45 lo immunophenotype (Matarraz et al., 2008) and by CD105 expression (Buhring et al., 1991; Rokhlin et al., 1995). As a matter of fact, CD105 and TGF-β 1 have a pivotal role in the regulation of the differentiation in the erythroid lineage (Fortunel et al., 2000; Moody et al., 2007). "
[Show abstract] [Hide abstract]
ABSTRACT: Despite of being described more than one decade ago (Pittenger et al., 1999), the immunophenotypic profile of bone marrow mesenchymal stem cells (MSC) still not well documented. The difficulty in achieving a detailed phenotypic characterization is common in less-represented cell populations and/or populations lacking a specific known cell marker, like bone marrow MSC.
The recent advances in flow cytometry technology and the emergence of new high-speed flow cytometers have given a valuable contribute to diminish this problem in two different (but complementary) aspects: 1) by reducing dramatically the acquisition time period, making it more reasonable to study minor cell populations; and 2) by increasing the number of parameters that can be analyzed per cell at the same time, which is critical to improve the immunophenotypic characterization of those not-well characterized cell populations that lack a specific known marker.
A good example of the practical usefulness of such technical developments is the description of different cell compartments in the bone marrow CD34+ hematopoietic stem cell (HSC) population. Detailed studies on this minor bone marrow cell population demonstrated that each compartment is committed to a different hematopoietic cell lineage. An extensive immunophenotypic characterization of those CD34+ compartments allowed the development of protocols to easily and quickly identify, quantify and evaluate phenotypic aberrations and maturational blocks in those cells, which is decisive to the diagnosis, prognosis, or follow-up of a variety of hematological clonal diseases (del Cañizo et al., 2003; Lochem et al., 2004; Matarraz et al., 2008; Orfao et al. 2004).
Available from: Ester Fonsatti
- "Basal layer of seminiferous tubules Burrows et al., 1995 Bone marrow cells Gougos and Letarte, 1988 Differentiated macrophages Lastres et al., 1992; O'Connell et al., 1992 Early B cells Rokhlin et al., 1995 Embryonic heart Qu et al., 1998 Endothelial cells Gougos and Letarte, 1988; Wang et al., 1993; Burrows et al., 1995; Altomonte et al., 1996; Miller et al., 1999 Extraglomerular interstitium Gougos and Letarte, 1988 Erythroid precursors Rokhlin et al., 1995 Fibroblasts Gougos and Letarte, 1988 Follicular dendritic cells Burrows et al., 1995 Glomerular mesangial matrix Gougos and Letarte, 1988 Heart mesenchymal cells Qu et al., 1998 Melanocytes Altomonte et al., 1996 Spleen red pulp Gougos and Letarte, 1988 Stromal cells Letarte et al., 1993; Rokhlin et al., 1995; Robledo et al., 1996 Stromal components in the prostate Burrows et al., 1995 Subset of circulating CD34 Pierelli et al., 2000 Syncytiotrophoblasts Lastres et al., 1992; Wang et al., 1993 Vascular smooth muscle cells Adam et al., 1998 As reported above, CD105 is preferentially and strongly expressed on endothelial cells. Noteworthy, highest levels of CD105 expression were identi®ed on human umbilical vein endothelial cells (HUVEC) with protein, RNA, and DNA levels consistent with cellular activation and proliferation (Burrows et al., 1995). "
[Show abstract] [Hide abstract]
ABSTRACT: Endoglin (CD105) is a cell membrane glycoprotein over-expressed on highly proliferating endothelial cells in culture, and on endothelial cells of angiogenetic blood vessels within benign and malignant tissues. CD105 binds several factors of the Transforming Growth Factor (TGF)-beta superfamily, and its over-expression modulates cellular responses to TGF-beta1. The complex of experimental findings accumulated in the last few years strongly indicate that CD105 is a powerful marker of angiogenesis, and that it might play a critical role in the pathogenesis of vascular diseases and in tumor progression. In this paper, we will review the structural, biological and functional features of CD105, as well as its distribution within normal and neoplastic tissues, emphasizing its foreseeable role as a molecular target for new diagnostic and bioimmunotherapeutic approaches in human malignancies.
Available from: Alessandra Battaglia
- "The present report represents the ®rst detailed description of CD105 expression on circulating adult CD34 cells and extends previous reports of endoglin expression on bone marrow CD34 cells and other haematopoietic cells (Rokhlin et al, 1995). More interestingly, we found that fractionation of circulating CD34 cells on the basis of CD105 expression yielded two distinct populations of haematopoietic progenitors, which differed signi®cantly in cloning capacity and proliferative response to cytokines in liquid culture. "
[Show abstract] [Hide abstract]
ABSTRACT: A subset of circulating CD34+ cells was found to express CD105 antigen. Sorting experiments showed that most granulocyte–macrophage colony-forming units (GM-CFU) and burst-forming units — erythroid (BFU-E) were retained in the CD34+/CD105− fraction, whereas rare GM-CFU/BFU-E were generated from CD34+/CD105+ cells. Megakaryocytic aggregates were entirely retained in the CD34+/CD105+ fraction. Neutralizing doses of an anti-TGF-β1 antibody demonstrated CD34+/CD105+ cells capable of colony-forming activity without any significant effect on CD34+/CD105− cells. Cloning of secondary colonies revealed that CD34+/CD105+ cells had a significantly higher secondary cloning efficiency than CD34+/CD105− cells. CD34+/CD105+ cells had a significantly higher long-term culture-initiating cell (LTC-IC) frequency than CD34+/CD105− cells. Kinetic analysis showed that 75% of CD34+/CD105+ cells consisted of DNA 2n G0Ki-67− cells whereas 82% of CD34+/CD105− were DNA 2n G1Ki-67+ cells, and this latter subset showed a RNA content consistently higher than CD34+/CD105+ cells. CD34+/CD105+ progenitors were CD25+, whereas CD34+/CD105− contained a small CD25+ subset. Three-colour analysis of bone marrow and cord blood CD34+ cells demonstrated that all the CD34+/CD38low/− primitive precursors were contained in CD34+/CD105+ cells. Extensive characterization of these CD105+ precursors indicated that they have biological properties associated with primitive haematopoietic precursors.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.