Murine metanephric mesenchyme possesses characteristics of vascular endothelial cells in vitro.
OBJECTIVE
Although the renal microvasculature, including the glomerular capillaries, is generally considered to develop from the metanephric mesenchyme, this has not been unequivocally demonstrated. Using a murine metanephric mesenchymal cell line (MS7), we tested whether the metanephric mesenchyme expresses phenotypic characteristics of endothelial cells and differentiates into vascular endothelial cells in vitro.


METHODS
MS7 cells were examined for the mRNA expression of endothelial markers by reverse transcription (RT)-PCR. Moreover, we attempted to induce the appearance of new endothelial markers by stimulation with growth factors and exposure to hypoxia.


RESULTS
Before induction, MS7 cells expressed mRNA of fetal liver kinase 1 (Flk1), fms-like tyrosine kinase (Flt1), tyrosine kinase with Ig and EGF homology domains 2 (Tie2), CD31, and podocalyxin. However, they did not express mRNA for vascular endothelial-cadherin (VE-cadherin) or von Willebrand factor (vWF), which are markers specific for endothelial cells and mature endothelial cells. In the immunocytochemical analysis, MS7 absorbed DiI-acetylated LDL virtually, but the results of staining with anti-VE-cadherin, vWF, or CD31 antibodies were negative. MS7 cells that were cultured for 14 days after reaching confluence began to express VE-cadherin and vWF mRNA. In addition, immunofluorescence showed abundant granules stained with anti-vWF antibody in the cytoplasm. Stimulation with vascular endothelial growth factor (VEGF), or basic fibroblast growth factor (bFGF), or exposure to a hypoxic condition did not influence their characteristic changes.


CONCLUSIONS
Our results suggest that metanephric mesenchymal (MS7) cells possess some characteristics of endothelial cells, and they are potent to differentiate into mature vascular endothelium in vitro.
Usui
Joichi
J
Department of Pathology and Nephrology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
Yamada
Risa
R
Kanemoto
Katsuyoshi
K
Koyama
Akio
A
Nagata
Michio
M
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015820:Cadherins / Q000235:genetics; D002454:Cell Differentiation; D002461:Cell Line, Transformed; D003594:Cytoplasmic Granules / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D007150:Immunohistochemistry; D007668:Kidney / Q000196:embryology*; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D010641:Phenotype; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014841:von Willebrand Factor / Q000235:genetics
D015415:Biomarkers; D015820:Cadherins; D012333:RNA, Messenger; D014841:von Willebrand Factor