Project description:Endothelial cells cover the lining of different blood vessels and lymph nodes, and have major functions including the transport of blood, homeostasis, inflammatory responses, control of infiltration of circulating cells into the tissues, and formation of new blood vessels. Therefore, understanding these cells is of major interest. The morphological features, phenotype and function of endothelial cells varies according to the vascular bed examined. The sialomucin, CD34, is widely used as an endothelial marker. However, CD34 is differentially expressed on endothelial cells in different organs and in pathological conditions. Little is known about regulation of endothelial CD34 expression or function. This marker is also strongly modified in-vitro in endothelial cell models, including human umbilical vein endothelial cells (HUVEC) and endothelial progenitor cells (EPC). We have therefore selected CD34high and CD34low endothelial cell subpopulations and examined their CD34 expression and function. Results: Transcriptomic analysis showed that CD34 gene and protein expressions are highly correlated, that CD34high cells are less proliferative, and have a stronger expression of IL-33 and Angiopoietin 2, compared to CD34low cells. Higher secretion levels of IL-33 by CD34high HUVECs was confirmed by ELISA. Finally, when endothelial cells were allowed to interact with peripheral blood mononuclear cells (PBMCs), CD34high endothelial cells induced a stronger proliferation of regulatory T lymphocytes (Tregs) compared to CD34low cells whereas expansion of other CD4+-T cell subsets was equivalent. These results suggest that CD34 expression by endothelial cells in-vitro associates with their ability to proliferate and with an immunogenic ability that favours the tolerogenic response.
Project description:The functional shift of quiescent endothelial cells into tip cells that migrate and stalk cells that proliferate is a key event during sprouting angiogenesis. We previously showed that the sialomucin CD34 is expressed in a small subset of cultured endothelial cells and that these cells extend filopodia: a hallmark of tip cells in vivo. In the present study, we characterized endothelial cells expressing CD34 in endothelial monolayers in vitro. We found that CD34-positive human umbilical vein endothelial cells show low proliferation activity and increased mRNA expression of all known tip cell markers, as compared to CD34- negative cells. Genome-wide mRNA profiling analysis of CD34-positive endothelial cells demonstrated enrichment for biological functions related to angiogenesis and migration, whereas CD34-negative cells were enriched for functions related to proliferation. In addition, we found an increase or decrease of CD34-positive cells in vitro upon exposure to stimuli that enhance or limit the number of tip cells in vivo, respectively. Our findings suggest cells with virtually all known properties of tip cells are present in vascular endothelial cell cultures and that they can be isolated based on expression of CD34. This novel strategy may open alternative avenues for future studies of molecular processes and functions in tip cells in angiogenesis. Four HUVEC donors were FACS-sorted by CD34 and divided in CD34-positive and CD34-negative fractions.
Project description:The functional shift of quiescent endothelial cells into tip cells that migrate and stalk cells that proliferate is a key event during sprouting angiogenesis. We previously showed that the sialomucin CD34 is expressed in a small subset of cultured endothelial cells and that these cells extend filopodia: a hallmark of tip cells in vivo. In the present study, we characterized endothelial cells expressing CD34 in endothelial monolayers in vitro. We found that CD34-positive human umbilical vein endothelial cells show low proliferation activity and increased mRNA expression of all known tip cell markers, as compared to CD34- negative cells. Genome-wide mRNA profiling analysis of CD34-positive endothelial cells demonstrated enrichment for biological functions related to angiogenesis and migration, whereas CD34-negative cells were enriched for functions related to proliferation. In addition, we found an increase or decrease of CD34-positive cells in vitro upon exposure to stimuli that enhance or limit the number of tip cells in vivo, respectively. Our findings suggest cells with virtually all known properties of tip cells are present in vascular endothelial cell cultures and that they can be isolated based on expression of CD34. This novel strategy may open alternative avenues for future studies of molecular processes and functions in tip cells in angiogenesis.
Project description:Endothelial cells cover the lining of different blood vessels and lymph nodes, and have major functions including the transport of blood, vessel homeostasis, inflammatory responses, control of transendothelial migration of circulating cells into the tissues, and formation of new blood vessels. Therefore, understanding these cells is of major interest. The morphological features, phenotype and function of endothelial cells varies according to the vascular bed examined. The sialomucin, CD34, is widely used as an endothelial marker. However, CD34 is differentially expressed on endothelial cells in different organs and in pathological conditions. Little is known about regulation of endothelial CD34 expression or function. Expression of CD34 is also strongly regulated in-vitro in endothelial cell models, including human umbilical vein endothelial cells (HUVEC) and endothelial colony forming cells (ECFC). We have therefore analysed the expression and function of CD34 by comparing CD34high and CD34low endothelial cell subpopulations. Transcriptomic analysis showed that CD34 gene and protein expressions are highly correlated, that CD34high cells proliferate less but express higher levels of IL-33 and Angiopoietin 2, compared with CD34low cells. Higher secretion levels of IL-33 and Angiopoietin 2 by CD34high HUVECs was confirmed by ELISA. Finally, when endothelial cells were allowed to interact with peripheral blood mononuclear cells, CD34high endothelial cells activated stronger proliferation of regulatory T lymphocytes (Tregs) compared to CD34low cells whereas expansion of other CD4+-T cell subsets was equivalent. These results suggest that CD34 expression by endothelial cells in-vitro associates with their ability to proliferate and with an immunogenic ability that favours the tolerogenic response.
Project description:CD34+ cells have been used to treat the patients with heart failure, but the outcome is variable. It is of great significance to scrutinize the fate and the mechanism of CD34+ cell differentiation in vivo during heart failure and explore its intervention strategy. By analyzing the transcriptomes of single cells from the Cd34-CreERT2;R26-tdTomato heart, we illustrated the dynamics of cell landscape during the progression of heart hypertrophy, including CD34+ cells, fibroblasts, endothelial cells and immune cells. And Our study also provides a cellular landscape of CD34+ cell-derived cells in the hypertrophy heart of animal models.
Project description:The label-free quantitative proteome was generated for 42 primary AML patient samples enriched for CD34+ cells (or mononuclear cells in the case of NPMcyt sameples) and as controls 6 mobilized peripheral blood CD34+ cells were included. Furthermore, 6 AML cell lines were included, and also primary mesenchymal stem cells grown under normaoxia or hypoxia were included.
Project description:A catalytic role has been proposed in neoplastic angiogenesis and cancer progression for bone marrow-derived endothelial progenitor cells (EPCs). However, in preclinical and clinical studies the quantitative role of marrow-derived EPCs in cancer vascularization was found to be extremely variable. Adipose tissue represents an attractive source of autologous adult stem cells due to its abundance and surgical accessibility. CD34+cells from Lipotransfer aspirates (LAs) of patients undergoing breast reconstruction after breast cancer surgery were compared with CD34+ cells from Leucapheresis of normal subjects. Two samples of purified CD34+ cells from Lipotransfer Aspirates (LAs) were compared with two samples of CD34+ cells from Leucapheresis samples. The reference were considered the CD34+ RNA from leucapheresis
Project description:The label-free quantitative proteome was generated for 30 primary AML patient samples enriched for CD34+ cells or CKIT+ cells in the case of NPMcyt samples. As controls 3 mobilized peripheral blood CD34+ cells were included.