Mesoderm induction and blood island formation by angiogenic growth factors and embryonic inducing factors

1989 ◽  
Vol 59 (3) ◽  
pp. 207-213 ◽  
Author(s):  
W. Kn�chel ◽  
H. Grunz ◽  
B. Loppnow-Blinde ◽  
H. Tiedemann
Development ◽  
1991 ◽  
Vol 111 (4) ◽  
pp. 1045-1055 ◽  
Author(s):  
J.L. Christian ◽  
J.A. McMahon ◽  
A.P. McMahon ◽  
R.T. Moon

In amphibian embryos, formation of the basic body plan depends on positional differences in the mesoderm. Although peptide growth factors involved in mesoderm induction have tentatively been identified, additional signals are required to generate pattern in this tissue. We have isolated a Xenopus cDNA for a Wnt-1 related gene, designated Xwnt-8, which is activated in response to mesoderm-inducing growth factors. Xwnt-8 transcripts are transiently expressed, being most abundant during gastrulation at which time expression is confined primarily to ventral mesodermal cells. Embryos dorsoanteriorized by exposure to lithium exhibit greatly reduced levels of Xwnt-8 mRNA, supporting a correlation between Xwnt-8 expression and a ventral mesodermal cell fate. Surprisingly, ectopic expression of Xwnt-8 in embryos causes a dorsoanterior-enhanced phenotype. These findings suggest that Xwnt-8 may be a secondary signalling agent which is produced in response to mesoderm-inducing factors and is involved in the early steps of mesodermal patterning.


2003 ◽  
Vol 89 (01) ◽  
pp. 190-197 ◽  
Author(s):  
Georg Breier ◽  
Hellmut Augustin

SummaryThe German Priority Research Program “Angiogenesis” (www.angiogenese.de) hosts a biannual meeting in the Kloster Seeon in Southern Germany. The 2nd Kloster Seeon Meeting “Angiogenesis: Molecular Mechanisms and Functional Interactions” was held in September 2002. It included sessions on hypoxia, the biology of endothelial precursor cells, angiogenic growth factors including VEGFs, the angiopoietins, ephrins, and FGFs, mechanisms of vascular sprouting and cell-cell contacts during angiogenesis, angiogenic signaling, lymphangiogenesis, angiogenesis during tumor invasion and metastasis, and on novel angiomanipulatory therapies. This report summarizes the key findings reported during the platform presentations of the meeting.


2020 ◽  
Vol 15 (1) ◽  
pp. 241-250
Author(s):  
Yan Chen ◽  
Jian Cao ◽  
Weixia Peng ◽  
Wen Chen

AbstractRapid endothelialization is an effective way to treat intimal hyperplasia after intravascular stent implantation. Blood vessels and nerves coordinate with each other in function, while neurotrophin-3 (NT-3) is an important class of nerve growth factors. Our study found that NT-3 promoted endothelial progenitor cell (EPC) mobilization, and the proportion of EPCs in peripheral blood was increased by 1.774 times compared with the control group. Besides, NT-3 promoted the expression of stromal cell-derived factor-1α (SDF-1α), matrix metalloproteinase-9 (MMP9), and chemokine (C-X-C motif) receptor 4 (CXCR4) in EPCs, which increased by 59.89%, 74.46%, and 107.7%, respectively, compared with the control group. Transwell experiments showed that NT-3 enhanced the migration of EPCs by 1.31 times. Flow chamber experiments demonstrated that NT-3 captured more circulating EPCs. As shown by ELISA results, NT-3 can promote the paracrine of vascular endothelial growth factor, interleukin-8, MMP-9, and SDF-1 from EPCs. Such increased angiogenic growth factors further accelerated the closure of endothelial cell scratches. Additionally, EPC-conditioned medium in the NT-3 group significantly inhibited the proliferation of vascular smooth muscle cells. Then animal experiments also illustrated that NT-3 prominently accelerated the endothelialization of injured carotid artery. In short, NT-3 accelerated rapid reendothelialization of injured carotid artery through promoting EPC mobilization and homing.


Development ◽  
1992 ◽  
Vol 114 (2) ◽  
pp. 285-302 ◽  
Author(s):  
J.M. Slack ◽  
D. Tannahill

Interest in the problem of anteroposterior specification has quickened because of our near understanding of the mechanism in Drosophila and because of the homology of Antennapedia-like homeobox gene expression patterns in Drosophila and vertebrates. But vertebrates differ from Drosophila because of morphogenetic movements and interactions between tissue layers, both intimately associated with anteroposterior specification. The purpose of this article is to review classical findings and to enquire how far these have been confirmed, refuted or extended by modern work. The “pre-molecular” work suggests that there are several steps to the process: (i) Formation of anteroposterior pattern in mesoderm during gastrulation with posterior dominance. (ii) Regional specific induction of ectoderm to form neural plate. (iii) Reciprocal interactions from neural plate to mesoderm. (iv) Interactions within neural plate with posterior dominance. Unfortunately, almost all the observable markers are in the CNS rather than in the mesoderm where the initial specification is thought to occur. This has meant that the specification of the mesoderm has been assayed indirectly by transplantation methods such as the Einsteckung. New molecular markers now supplement morphological ones but they are still mainly in the CNS and not the mesoderm. A particular interest attaches to the genes of the Antp-like HOX clusters since these may not only be markers but actual coding factors for anteroposterior levels. We have a new understanding of mesoderm induction based on the discovery of activins and fibroblast growth factors (FGFs) as candidate inducing factors. These factors have later consequences for anteroposterior pattern with activin tending to induce anterior, and FGF posterior structures. Recent work on neural induction has implicated cAMP and protein kinase C (PKC) as elements of the signal transduction pathway and has provided new evidence for the importance of tangential neural induction. The regional specificity of neural induction has been reinvestigated using molecular markers and provides conclusions rather similar to the classical work. Defects in the axial pattern may be produced by retinoic acid but it remains unclear whether its effects are truly coordinate ones or are concentrated in certain regions of high sensitivity. In general the molecular studies have supported and reinforced the “pre-molecular ones”. Important questions still remain: (i) How much pattern is there in the mesoderm (how many states?) (ii) How is this pattern generated by the invaginating organizer? (iii) Is there one-to-one transmission of codings to the neural plate? (iv) What is the nature of the interactions within the neural plate? (v) Are the HOX cluster genes really the anteroposterior codings?


Development ◽  
1989 ◽  
Vol 106 (4) ◽  
pp. 775-785 ◽  
Author(s):  
D. Tannahill ◽  
D.A. Melton

The Xenopus Vg1 gene encodes a maternal mRNA that is localized to the vegetal hemisphere of both oocytes and embryos and encodes a protein related to the TGF-beta family of small secreted growth factors. We have raised antibodies to recombinant Vg1 protein and used them to show that Vg1 protein is first detected in stage IV oocytes and reaches maximal levels in stage VI oocytes and eggs. During embryogenesis, Vg1 protein is synthesized until the gastrula stage. The embryonically synthesized Vg1 protein is present only in vegetal cells of an early blastula. We find that Vg1 protein is glycosylated and associated with membranes in the early embryo. Our results also suggest that a small proportion of the full-length Vg1 protein is cleaved to give a small peptide of M(r) = approximately 17 × 10(3). These results support the proposal that the Vg1 protein is an endogenous growth-factor-like molecule involved in mesoderm induction within the amphibian embryo.


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