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Paracrine and autocrine regulation of vascular endothelial growth factor during tissue differentiation in the quail
Author(s) -
Aitkenhead Mark,
Christ Bodo,
Eichmann Anne,
Feucht Matthias,
Wilson David J.,
Wilting Jörg
Publication year - 1998
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/(sici)1097-0177(199805)212:1<1::aid-aja1>3.0.co;2-l
Subject(s) - paracrine signalling , biology , angiogenesis , quail , vascular endothelial growth factor , autocrine signalling , endocrinology , medicine , mesonephros , vascular endothelial growth factor a , vascular endothelial growth factor b , neural tube , vasculogenesis , mesenchyme , microbiology and biotechnology , embryo , stem cell , cancer research , embryonic stem cell , receptor , vegf receptors , progenitor cell , biochemistry , gene
The expression of vascular endothelial growth factor (VEGF) has been described to coincide both temporally and spatially with angiogenesis suggesting a role as a paracrine stimulator of endothelial cells. We have used digoxigenin labelled RNA probes to VEGF and the VEGF receptor‐2 ( Quek1 ) to investigate the relationship between VEGF expression and vascular events in quail embryos from day 1 to 13 of incubation. Furthermore, the effect of exogenously applied VEGF was studied in day 4 quail embryos using polyclonal anti‐VEGF antibodies. Expression of VEGF mRNA was observed in day 1 and 2 embryos in regions of active angiogenesis and hemangiopoiesis. VEGF mRNA expression was found at high levels in the ventral aspect of the neural tube and Quek1 mRNA expression in the accompanying endothelial cells of day 3 embryos, suggesting a function in brain angiogenesis. However, in the neural tube, thyroid gland and cartilaginous skeleton VEGF mRNA was expressed at least 1 day before the ingrowth of vessels, suggesting that additional mechanisms are involved in control of angiogenesis. This is supported by the observation that application of VEGF 165 into the midbrain induced dilatation of perineural vessels, while the intraneural vessels remained almost unaffected. Expression of VEGF mRNA was also observed at high levels in podocytes during all stages, indicative of its importance in glomerular development and function. The results of the present study indicate that as angiogenesis occurred in other tissues and organs (day 13 metanephros, dorsal third of the day 7 neural tube, skeletal muscle, and many mesodermal compartments), there was concurrent paracrine expression of VEGF mRNA and Quek1 mRNA. One noteable exception was the hepatocytes of the developing liver which appeared to remain VEGF‐negative throughout the study. However, a small number of endothelial cells within liver sinuses, and additionally within the kidney and the elastic arteries, expressed VEGF mRNA. These results suggest that VEGF may also act as an autocrine mediator of angiogenesis, possibly as a result of localised tissue hypoxia. Dev. Dyn. 1998;212:1–13. © 1998 Wiley‐Liss, Inc.