Insufficient VEGFA activity in yolk sac endoderm compromises haematopoietic and endothelial differentiation

Development ◽  
2002 ◽  
Vol 129 (8) ◽  
pp. 1881-1892 ◽  
Author(s):  
Annette Damert ◽  
Lucile Miquerol ◽  
Marina Gertsenstein ◽  
Werner Risau ◽  
Andras Nagy

Vascular endothelial growth factor A (VEGFA) plays a pivotal role in the first steps of endothelial and haematopoietic development in the yolk sac, as well as in the establishment of the cardiovascular system of the embryo. At the onset of gastrulation, VEGFA is primarily expressed in the yolk sac visceral endoderm and in the yolk sac mesothelium. We report the generation and analysis of a Vegf hypomorphic allele, Vegflo. Animals heterozygous for the targeted mutation are viable. Homozygous embryos, however, die at 9.0 dpc because of severe abnormalities in the yolk sac vasculature and deficiencies in the development of the dorsal aortae. We find that providing ‘Vegf wild-type’ visceral endoderm to the hypomorphic embryos restores normal blood and endothelial differentiation in the yolk sac, but does not rescue the phenotype in the embryo proper. In the opposite situation, however, when Vegf hypomorphic visceral endoderm is provided to a wild-type embryo, the ‘Vegf wild-type’ yolk sac mesoderm is not sufficient to support proper vessel formation and haematopoietic differentiation in this extra-embryonic membrane. These findings demonstrate that VEGFA expression in the visceral endoderm is absolutely required for the normal expansion and organisation of both the endothelial and haematopoietic lineages in the early sites of vessel and blood formation. However, normal VEGFA expression in the yolk sac mesoderm alone is not sufficient for supporting the proper development of the early vascular and haematopoietic system.

Endocrinology ◽  
2008 ◽  
Vol 149 (5) ◽  
pp. 2176-2183 ◽  
Author(s):  
Bianca Hemmeryckx ◽  
Rita van Bree ◽  
Berthe Van Hoef ◽  
Lisbeth Vercruysse ◽  
H. Roger Lijnen ◽  
...  

Pregnancy-induced metabolic changes are regulated by signals from an expanded adipose organ. Placental growth factor (PlGF), acting through vascular endothelial growth factor receptor-1, may be among those signals. There is a steep rise in circulating PlGF during normal pregnancy, which is repressed in gravidas who develop preeclampsia. PlGF-deficiency in mice impairs adipose vascularization and development. Here we studied young-adult PlGF-deficient (PlGF−/−) and wild-type mice on a high-fat diet in the nongravid state and at embryonic day (E) 13.5 or E18.5 of gestation. Litter size and weight were normal, but E18.5 placentas were smaller in PlGF−/− pregnancies. PlGF−/− mice showed altered intraadipose dynamics, with the following: 1) less blood vessels and fewer brown, uncoupling protein (UCP)-1-positive, adipocytes in white sc and perigonadal fat compartments and 2) white adipocyte hypertrophy. The mRNA expression of β3-adrenergic receptors, peroxisome proliferator-activated receptor-γ coactivator-1α, and UCP-1 was decreased accordingly. Moreover, PlGF−/− mice showed hyperinsulinemia. Pregnancy-associated changes were largely comparable in PlGF−/− and wild-type dams. They included expanded sc fat compartments and adipocyte hypertrophy, whereas adipose expression of key angiogenesis/adipogenesis (vascular endothelial growth factor receptor-1, peroxisome proliferator-activated receptor-γ2) and thermogenesis (β3-adrenergic receptors, peroxisome proliferator-activated receptor-γ coactivator-1α, and UCP-1) genes was down-regulated; circulating insulin levels gradually increased during pregnancy. In conclusion, reduced adipose vascularization in PlGF−/− mice impairs adaptive thermogenesis in favor of energy storage, thereby promoting insulin resistance and hyperinsulinemia. Pregnancy adds to these changes by PlGF-independent mechanisms. Disturbed intraadipose dynamics is a novel mechanism to explain metabolic changes in late pregnancy in general and preeclamptic pregnancy in particular.


2010 ◽  
Vol 78 (11) ◽  
pp. 4723-4733 ◽  
Author(s):  
Styliani Antonara ◽  
Laura Ristow ◽  
James McCarthy ◽  
Jenifer Coburn

ABSTRACT The Borrelia burgdorferi surface lipoprotein OspC is a critical virulence factor, but its precise role in the establishment of B. burgdorferi infection remains unclear. To determine whether OspC affects the host response at the site of inoculation of the bacterium, the recruitment of macrophages and neutrophils and the production of cytokines were examined at the site of infection by wild-type, ospC mutant, and complemented mutant B. burgdorferi strains. Of the 21 cytokines tested, monocyte chemoattractant protein 1 (MCP-1), keratinocyte-derived chemokine (KC, CXCL1), and vascular endothelial growth factor (VEGF) were found at increased levels at the site of inoculation of B. burgdorferi, and the levels varied with the production of OspC at one or more time points over the 1-week course of infection. The kinetics of expression and the dependence on OspC production by B. burgdorferi varied among the cytokines. The production of KC and MCP-1, and the appearance of monocytic infiltrates, correlated with the presence of the bacteria rather than with OspC specifically. In contrast, VEGF production was not correlated simply to the presence of the bacteria and is influenced by the presence of OspC. In in vitro assays, OspC and B. burgdorferi expressing OspC stimulated the growth of endothelial cells more than did the controls. These data suggest the possibility of a novel role for OspC in the life of B. burgdorferi at the interface of its mammalian and tick hosts.


2014 ◽  
Vol 28 (12) ◽  
pp. 1934-1947 ◽  
Author(s):  
Yuechao Zhao ◽  
Quanxi Li ◽  
Benita S. Katzenellenbogen ◽  
Lester F. Lau ◽  
Robert N. Taylor ◽  
...  

Endometriosis is a prevalent gynecological disorder in which endometrial tissue proliferates in extrauterine sites, such as the peritoneal cavity, eventually giving rise to painful, invasive lesions. Dysregulated estradiol (E) signaling has been implicated in this condition. However, the molecular mechanisms that operate downstream of E in the ectopic endometrial tissue are unknown. To investigate these mechanisms, we used a mouse model of endometriosis. Endometrial tissue from donor mice was surgically transplanted on the peritoneal surface of immunocompetent syngeneic recipient mice, leading to the establishment of cystic endometriosis-like lesions. Our studies revealed that treatment with E led to an approximately 3-fold increase in the lesion size within a week of transplantation. E also caused a concomitant stimulation in the expression of connective tissue growth factor/Cyr61/Nov (CCN1), a secreted cysteine-rich matricellular protein, in the lesions. Interestingly, CCN1 is highly expressed in human ectopic endometriotic lesions. To address its role in endometriosis, endometrial tissue from Ccn1-null donor mice was transplanted in wild-type recipient mice. The resulting ectopic lesions were reduced up to 75% in size compared with wild-type lesions due to diminished cell proliferation and cyst formation. Notably, loss of CCN1 also disrupted the development of vascular networks in the ectopic lesions and reduced the expression of several angiogenic factors, such as vascular endothelial growth factor-A and vascular endothelial growth factor-C. These results suggest that CCN1, acting downstream of E, critically controls cell proliferation and neovascularization, which support the growth and survival of endometriotic tissue at ectopic sites. Blockade of CCN1 signaling during the early stages of lesion establishment may provide a therapeutic avenue to control endometriosis.


2018 ◽  
Vol 7 (1) ◽  
pp. 101-106 ◽  
Author(s):  
Paula Fratini ◽  
Nathia Nathaly Rigoglio ◽  
Gustavo de Sá Schiavo Matias ◽  
Ana Claudia O. Carreira ◽  
Rose Eli Grassi Rici ◽  
...  

Blood ◽  
2002 ◽  
Vol 100 (10) ◽  
pp. 3828-3831 ◽  
Author(s):  
Wen-Mei Yu ◽  
Teresa S. Hawley ◽  
Robert G. Hawley ◽  
Cheng-Kui Qu

Hematopoiesis initiates in the extraembryonic yolk sac. To isolate various types of precursor cells from this blood cell–forming tissue, yolk sac cells were immortalized by retroviral-mediated expression of the HOX11 homeobox-containing gene. Among the cell lines derived, some were able to spontaneously generate adherent stromal-like cells capable of taking up acetylated low-density lipoprotein, and they could be induced to form tubelike structures when cultured on Matrigel. Although these cell lines were negative for hematopoietic cell surface markers, they gave rise to hematopoietic colonies—containing cells belonging to the monocytic, megakaryocytic, and definitive erythroid lineages—when plated in methylcellulose medium supplemented with hematopoietic growth factors. Low amounts of Flk-1 mRNA could be detected in these cells, and they showed significant responsiveness to vascular endothelial growth factor, stem cell factor, basic fibroblast growth factor, and interleukin 6. They also expressed the transcription factors SCL, GATA2, GATA1, PU.1, and c-myb. These yolk sac–derived cell lines may represent a transitional stage of early hematopoietic development.


2005 ◽  
Vol 25 (6) ◽  
pp. 2441-2449 ◽  
Author(s):  
Megan E. Baldwin ◽  
Michael M. Halford ◽  
Sally Roufail ◽  
Richard A. Williams ◽  
Margaret L. Hibbs ◽  
...  

ABSTRACT Vascular endothelial growth factor receptor 3 (Vegfr-3) is a tyrosine kinase that is expressed on the lymphatic endothelium and that signals for the growth of the lymphatic vessels (lymphangiogenesis). Vegf-d, a secreted glycoprotein, is one of two known activating ligands for Vegfr-3, the other being Vegf-c. Vegf-d stimulates lymphangiogenesis in tissues and tumors; however, its role in embryonic development was previously unknown. Here we report the generation and analysis of mutant mice deficient for Vegf-d. Vegf-d-deficient mice were healthy and fertile, had normal body mass, and displayed no pathologic changes consistent with a defect in lymphatic function. The lungs, sites of strong Vegf-d gene expression during embryogenesis in wild-type mice, were normal in Vegf-d-deficient mice with respect to tissue mass and morphology, except that the abundance of the lymphatics adjacent to bronchioles was slightly reduced. Dye uptake experiments indicated that large lymphatics under the skin were present in normal locations and were functional. Smaller dermal lymphatics were similar in number, location, and function to those in wild-type controls. The lack of a profound lymphatic phenotype in Vegf-d-deficient mice suggests that Vegf-d does not play a major role in lymphatic development or that Vegf-c or another, as-yet-unknown activating Vegfr-3 ligand can compensate for Vegf-d during development.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
G. Wetzel ◽  
B. Relja ◽  
A. Klarner ◽  
D. Henrich ◽  
N. Dehne ◽  
...  

Background. Hypoxia-inducible factor-1α(HIF-1α) and NF-κB play important roles in the inflammatory response after hemorrhagic shock and resuscitation (H/R). Here, the role of myeloid HIF-1αin liver hypoxia, injury, and inflammation after H/R with special regard to NF-κB activation was studied.Methods. Mice with a conditional HIF-1αknockout (KO) in myeloid cell-line and wild-type (WT) controls were hemorrhaged for 90 min (30±2 mm Hg) and resuscitated. Controls underwent only surgical procedures.Results. After six hours, H/R enhanced the expression of HIF-1α-induced genes vascular endothelial growth factor (VEGF) and adrenomedullin (ADM). In KO mice, this was not observed. H/R-induced liver injury in HIF-1αKO was comparable to WT. Elevated plasma interleukin-6 (IL-6) levels after H/R were not reduced by HIF-1αKO. Local hepatic hypoxia was not significantly reduced in HIF-1αKO compared to controls after H/R. H/R-induced NF-κB phosphorylation in liver did not significantly differ between WT and KO.Conclusions. Here, deleting HIF-1αin myeloid cells and thereby in Kupffer cells was not protective after H/R. This data indicates that other factors, such as NF-κB, due to its upregulated phosphorylation in WT and KO mice, contrary to HIF-1α, are rather key modulators of inflammation after H/R in our model.


Endocrinology ◽  
2005 ◽  
Vol 146 (7) ◽  
pp. 2952-2962 ◽  
Author(s):  
C. Cristina ◽  
G. Díaz-Torga ◽  
A. Baldi ◽  
A. Góngora ◽  
M. Rubinstein ◽  
...  

Abstract Vascular endothelial growth factor (VEGF)-A is an important angiogenic cytokine in cancer and pathological angiogenesis and has been related to the antiangiogenic activity of dopamine in endothelial cells. We investigated VEGF expression, localization, and function in pituitary hyperplasia of dopamine D2 receptor (D2R)-knockout female mice. Pituitaries from knockout mice showed increased protein and mRNA VEGF-A expression when compared with wild-type mice. In wild-type mice, prolonged treatment with the D2R antagonist, haloperidol, enhanced pituitary VEGF expression and prolactin release, suggesting that dopamine inhibits pituitary VEGF expression. VEGF expression was also increased in pituitary cells from knockout mice, even though these cells proliferated less in vitro when compared with wild-type cells, as determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium proliferation assay, proliferating cell nuclear antigen expression, and [3H]thymidine incorporation. In contrast to other animal models, estrogen did not increase pituitary VEGF protein and mRNA expression and lowered serum prolactin secretion in vivo and in vitro in both genotypes. VEGF (10 and 30 ng/ml) did not modify pituitary cell proliferation in either genotype and increased prolactin secretion in vitro in estrogen-pretreated cells of both genotypes. But conditioned media from D2R−/− cells enhanced human umbilical vein cell proliferation, and this effect could be partially inhibited by an anti-VEGF antiserum. Finally, using dual-labeling immunofluorescence and confocal laser microscopy, we found that in the hyperplastic pituitaries, VEGF-A was mostly present in follicle-stellate cells. In conclusion, pituitary VEGF expression is under dopaminergic control, and even though VEGF does not promote pituitary cellular proliferation in vitro, it may be critical for pituitary angiogenesis through paracrine actions in the D2R knockout female mice.


2001 ◽  
Vol 193 (12) ◽  
pp. 1383-1392 ◽  
Author(s):  
Irene Nunes ◽  
Rosemary D. Higgins ◽  
Lucia Zanetta ◽  
Peter Shamamian ◽  
Stephen P. Goff

The requirement for the nonreceptor tyrosine kinase c-abl in the pathogenesis of retinopathy of prematurity (ROP) was examined using the mouse model for ROP and c-abl–deficient mice. Hyperoxia-induced retinal neovascularization was observed in wild-type and heterozygous mice but animals that were homozygous null for c-abl did not develop a vasoproliferative retinopathy in response to hyperoxia. Two gene products, endothelin-1 (ET-1) and vascular endothelial growth factor (VEGF), have been implicated in the pathogenesis of ROP. The mRNA expression of ET-1 and VEGF was assessed in mice maintained in normoxia and in hyperoxia-exposed mice. ET-1 mRNA levels were unchanged in wild-type mice throughout the hyperoxia treatment, suggesting that ET-1 mRNA expression is not regulated by the increase in inspired oxygen. In wild-type mice maintained in room air, VEGF mRNA levels rose threefold from postnatal day 6 (P6) to P17. When wild-type mice were treated with the hyperoxia regimen, a fivefold decrease in VEGF mRNA expression was observed from P7 to P16. However, retinal VEGF expression in hyperoxia-treated homozygous null mice did not decrease and remained at control levels. These data suggest that c-abl is required for the hyperoxia-induced retinal neovascularization and hyperoxia-induced decrease in VEGF mRNA levels.


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