Cell autonomous functions of the receptor tyrosine kinase TIE in a late phase of angiogenic capillary growth and endothelial cell survival during murine development

Development ◽  
1996 ◽  
Vol 122 (10) ◽  
pp. 3013-3021 ◽  
Author(s):  
J. Partanen ◽  
M.C. Puri ◽  
L. Schwartz ◽  
K.D. Fischer ◽  
A. Bernstein ◽  
...  

TIE is a receptor tyrosine kinase expressed in both mature endothelial cells and their precursors, as well as in some hematopoietic cells. Mouse embryos homozygous for a disrupted Tie allele die at midgestation due to impaired endothelial cell integrity and resulting hemorrhage. Here we have performed chimeric analysis to study further the function of the murine TIE in the development of embryonic vasculature and in the hematopoietic system. Cells lacking a functional Tie gene (tie(lcz)/tie(lczn-) cells) contributed to the embryonic vasculature at E10.5 as efficiently as cells heterozygous for a targeted Tie allele (tie(lcz)/+ cells). Thus, TIE does not play a significant role in vasculogenesis or in early angiogenic processes, such as formation of the intersomitic arteries and limb bud vascularization. At E15.5 tie(lcz)/tie(lczn-) cells still readily contributed to major blood vessels and to endothelial cells of organs such as lung and heart, which have been suggested to be vascularized by angioblast differentiation. In contrast, the tie(lcz)/tie(lczn-) cells were selected against in the capillary plexuses of several angiogenically vascularized tissues, such as brain and kidney. Our results thus support a role for TIE in late phases of angiogenesis but not vasculogenesis. Furthermore, the results suggest that different mechanisms regulate early and late angiogenesis and provide support for a model of differential organ vascularization by vasculogenic or angiogenic processes. Analysis of adult chimeras suggested that TIE is required to support the survival or proliferation of certain types of endothelial cells demonstrating heterogeneity in the growth/survival factor requirements in various endothelial cell populations. Chimeric analysis of adult hematopoietic cell populations, including peripheral platelets and bone marrow progenitor cells, revealed that tie(lcz)/tie(lczn-) cells were able to contribute to these cell types in a way indistinguishable from tie(lcz)/+ or wild-type cells. Thus, the primary function of TIE appears to be restricted to the endothelial cell lineage.

2002 ◽  
Vol 283 (2) ◽  
pp. L297-L304 ◽  
Author(s):  
Larissa A. Shimoda ◽  
Laura E. Welsh ◽  
David B. Pearse

Endothelial barrier dysfunction is typically triggered by increased intracellular Ca2+concentration. Membrane-permeable analogs of guanosine 3′,5′-cyclic monophosphate (cGMP) prevent disruption of endothelial cell integrity. Because membrane potential ( E m), which influences the electrochemical gradient for Ca2+ influx, is regulated by K+ channels, we investigated the effect of 8-bromo-cGMP on E m and inwardly rectifying K+ (KIR) currents in bovine pulmonary artery and microvascular endothelial cells (BPAEC and BMVEC), using whole cell patch-clamp techniques. Both cell types exhibited inward currents at potentials negative to −50 mV that were abolished by application of 10 μM Ba2+, consistent with KIR current. Ba2+ also depolarized both cell types. 8-Bromo-cGMP (10−3 M) depolarized BPAEC and BMVEC and inhibited KIR current. Pretreatment with Rp-8-cPCT-cGMPS or KT-5823, protein kinase G (PKG) antagonists, did not prevent current inhibition by 8-bromo-cGMP. These data suggest that 8-bromo-cGMP induces depolarization in BPAEC and BMVEC due, in part, to PKG-independent inhibition of KIR current. The depolarization could be a protective mechanism that prevents endothelial cell barrier dysfunction by reducing the driving force for Ca2+ entry.


1997 ◽  
Vol 273 (1) ◽  
pp. L275-L281 ◽  
Author(s):  
M. Geiger ◽  
A. Stone ◽  
S. N. Mason ◽  
K. T. Oldham ◽  
K. S. Guice

Phenotypic heterogeneity among endothelial cell populations may account for important organ-specific behaviors. Experimental evidence suggests that endothelium-derived nitric oxide mediates certain of these unique responses. The purpose of these investigations was to compare rat pulmonary microvascular endothelial cells with pulmonary artery and aortic macrovascular endothelial cells in their ability to generate nitric oxide (NO). Cultures of these microvascular and macrovascular endothelial cells were incubated with interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and Salmonella typhimurium lipopolysaccharide (LPS) alone or in combination, and nitrite production was measured. Single-agent exposure with IFN-gamma (up to 1,000 U/ml), TNF-alpha (up to 60,000 U/ml), or LPS (up to 500 ng/ml) had little effect on nitrite generation. Nitrite production by rat aortic macrovascular endothelial cells (RAEC) was significantly greater than that by the rat lung microvascular endothelial cells (RLMVEC) when stimulated with TNF-alpha + IFN-gamma, LPS + IFN-gamma, or TNF-alpha + LPS. The maximal response by all endothelial cell types (approximately 15-fold increase in RAEC and 8-fold increase in RLMVEC) was observed with LPS + IFN-gamma. The nitrite generation from rat pulmonary artery endothelial cells was intermediate between RAEC and RLMVEC responses when stimulated with IFN-gamma + LPS or TNF-alpha. Similar patterns of heterogeneous inducible nitric oxide synthase mRNA induction occurred when Northern analysis of specimens from the cultured endothelial cell types was done. These data suggest that phenotypic heterogeneity between these endothelial cell populations is substantial and, by inference, that site-specific NO. generation may occur.


2020 ◽  
Author(s):  
Emmi Helle ◽  
Minna Ampuja ◽  
Alexandra Dainis ◽  
Laura Antola ◽  
Elina Temmes ◽  
...  

AbstractRationaleCell-cell interactions are crucial for the development and function of the organs. Endothelial cells act as essential regulators of tissue growth and regeneration. In the heart, endothelial cells engage in delicate bidirectional communication with cardiomyocytes. The mechanisms and mediators of this crosstalk are still poorly known. Furthermore, endothelial cells in vivo are exposed to blood flow and their phenotype is greatly affected by shear stress.ObjectiveWe aimed to elucidate how cardiomyocytes regulate the development of organotypic phenotype in endothelial cells. In addition, the effects of flow-induced shear stress on endothelial cell phenotype were studied.Methods and resultsHuman induced pluripotent stem cell (hiPSC) -derived cardiomyocytes and endothelial cells were grown either as a monoculture or as a coculture. hiPS-endothelial cells were exposed to flow using the Ibidi-pump system. Single-cell RNA sequencing was performed to define cell populations and to uncover the effects on their transcriptomic phenotypes. The hiPS-cardiomyocyte differentiation resulted in two distinct populations; atrial and ventricular. Coculture had a more pronounced effect on hiPS-endothelial cells compared to hiPS-cardiomyocytes. Coculture increased hiPS-endothelial cell expression of transcripts related to vascular development and maturation, cardiac development, and the expression of cardiac endothelial cell -specific genes. Exposure to flow significantly reprogrammed the hiPS-endothelial cell transcriptome, and surprisingly, promoted the appearance of both venous and arterial clusters.ConclusionsSingle-cell RNA sequencing revealed distinct atrial and ventricular cell populations in hiPS-cardiomyocytes, and arterial and venous-like cell populations in flow exposed hiPS-endothelial cells. hiPS-endothelial cells acquired cardiac endothelial cell identity in coculture. Our study demonstrated that hiPS-cardiomoycytes and hiPS-endothelial cells readily adapt to coculture and flow in a consistent and relevant manner, indicating that the methods used represent improved physiological cell culturing conditions that potentially are more relevant in disease modelling. In addition, novel cardiomyocyte-endothelial cell crosstalk mediators were revealed.


Author(s):  
Emmi Helle ◽  
Minna Ampuja ◽  
Alexandra Dainis ◽  
Laura Antola ◽  
Elina Temmes ◽  
...  

Cell-cell interactions are crucial for organ development and function. In the heart, endothelial cells engage in bidirectional communication with cardiomyocytes regulating cardiac development and growth. We aimed to elucidate the organotypic development of cardiac endothelial cells and cardiomyocyte and endothelial cell crosstalk using human induced pluripotent stem cells (hiPSC). Single-cell RNA sequencing was performed with hiPSC-derived cardiomyocytes (hiPS-CMs) and endothelial cells (hiPS-ECs) in mono- and co-culture. The presence of hiPS-CMs led to increased expression of transcripts related to vascular development and maturation, cardiac development, as well as cardiac endothelial cell and endocardium-specific genes in hiPS-ECs. Interestingly, co-culture induced the expression of cardiomyocyte myofibrillar genes and MYL7 and MYL4 protein expression was detected in hiPS-ECs. Major regulators of BMP- and Notch-signaling pathways were induced in both cell types in co-culture. These results reflect the findings from animal studies and extend them to human endothelial cells, demonstrating the importance of EC-CM interactions during development.


Blood ◽  
1994 ◽  
Vol 84 (8) ◽  
pp. 2422-2430 ◽  
Author(s):  
FC Zeigler ◽  
BD Bennett ◽  
CT Jordan ◽  
SD Spencer ◽  
S Baumhueter ◽  
...  

The flk-2/flt-3 receptor tyrosine kinase was cloned from a hematopoietic stem cell population and is considered to play a potential role in the developmental fate of the stem cell. Using antibodies derived against the extracellular domain of the receptor, we show that stem cells from both murine fetal liver and bone marrow can express flk-2/flt-3. However, in both these tissues, there are stem cell populations that do not express the receptor. Cell cycle analysis shows that stem cells that do not express the receptor have a greater percentage of the population in G0 when compared with the flk-2/flt-3- positive population. Development of agonist antibodies to the receptor shows a proliferative role for the receptor in stem cell populations. Stimulation with an agonist antibody gives rise to an expansion of both myeloid and lymphoid cells and this effect is enhanced by the addition of kit ligand. These studies serve to further illustrate the importance of the flk-2/flt-3 receptor in the regulation of the hematopoietic stem cell.


Development ◽  
1971 ◽  
Vol 26 (1) ◽  
pp. 135-156
Author(s):  
R. A. Elton ◽  
C. A. Tickle

1. This work presents a quantitative measure, α, of the degree of segregation of two cell types in sections of aggregates, and some results obtained with the measure relating to ‘sorting out’. The method is designed particularly for the case where labelling of one type of cell is incomplete, and the importance of this effect is assessed. Possible problems in formulating such a model are discussed. The measure α is compared with methods used in investigations of segregation in plant communities. 2. Segregation of chick heart and limb-bud cells in mixed aggregates has been analysed using α. In control aggregates of mixtures of labelled and unlabelled cells of one type, α is near to its random value of 1, and we suggest that the departure from random can be adequately accounted for by cell division. In mixed aggregates, significant segregation is consistently found, even in aggregates formed after 2 and 4 h. Both disaggregation procedures (EDTA, trypsin or trypsin + EDTA) and reaggregation methods (reciprocating or gyratory shaker) are found to have an effect on the degree of segregation. Possible reasons for these findings are discussed. 3. Positioning of the cells relative to the outside of aggregates is also investigated for some of the aggregates.


2009 ◽  
Vol 20 (4) ◽  
pp. 763-770 ◽  
Author(s):  
Marjut Puputti ◽  
Olli Tynninen ◽  
Paula Pernilä ◽  
Marko Salmi ◽  
Sirpa Jalkanen ◽  
...  

1987 ◽  
Vol 245 (1) ◽  
pp. 151-157 ◽  
Author(s):  
E R Hall ◽  
C E Manner ◽  
J Carinhas ◽  
R Snopko ◽  
M Rafelson

The asymmetric distribution of phospholipids in bovine endothelial-cell membranes was probed with 2,4,6-trinitrobenzenesulphonate and purified phospholipase A2. The data suggest that phosphotidylethanolamine is primarily located in the inner lipid bilayer, as reported for other cell types. Stearic acid is taken up by the endothelial cells and is randomly distributed among the membrane phospholipids. In contrast, the polyunsaturated fatty acids (arachidonic, eicosatrienoic and eicosapentaenoic acids) have initial incorporation into the phosphatidylcholine fraction. These fatty acids then undergo a time-dependent transfer from phosphatidylcholine to phosphatidylethanolamine. Thus we propose that endothelial cells possess a mechanism for the selective internalization of polyunsaturated fatty acids.


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