Skeletal myogenic progenitors in the endothelium of lung and yolk sac.
We previously showed that clonable skeletal myogenic cells can be derived from the embryonic aorta but become very rare in the more mature and structured fetal aorta. The aim of this study was to investigate whether, during fetal and postnatal development, these myogenic progenitors progressively disappear or may rather associate with the microvascular district, being thus distributed to virtually all tissues. To test this hypothesis, we used F1 embryos (or mice) from a transgenic line expressing a striated muscle-specific reporter gene (LacZ) crossed with a transgenic line expressing a different endothelial-specific reporter genes (GFP). Endothelial cells were isolated from yolk sac (at E11) and lung (at E11, E17, P1, P10, and P60), two organs embryologically unrelated to paraxial mesoderm, rich in vessels, and devoid of skeletal muscle. Endothelial cells, purified by magnetic bead selection (CD31/PECAM-1(+)) or cell sorting (Tie2-GFP(+)) were then challenged for their skeletal myogenic potential in vitro and in vivo. The results demonstrated that both yolk sac and lung contain progenitor cells, which express endothelial markers and are endowed with a skeletal myogenic potential that they reveal when in the presence of differentiating myoblasts, in vitro, and regenerating muscle, in vivo. The number (or potency to generate skeletal muscle) of these vessels associated cells decreases rapidly with age and is very low in mature animals, possibly correlating with reduced regenerative capacity of adult mammalian tissues.
Cusella De Angelis
Maria Gabriella
MG
Department of Experimental Medicine, University of Pavia, Pavia, Italy. cusella.gabriella@hsr.it
Balconi
Giovanna
G
Bernasconi
Sergio
S
Zanetta
Lucia
L
Boratto
Renata
R
Galli
Daniela
D
Dejana
Elisabetta
E
Cossu
Giulio
G
D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D015415:Biomarkers / Q000032:analysis; D002460:Cell Line; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism; D005260:Female; D018189:Immunomagnetic Separation; D008168:Lung / Q000196:embryology* / Q000378:metabolism; D051379:Mice; D016513:Mice, SCID; D008822:Mice, Transgenic; D024510:Muscle Development; D018482:Muscle, Skeletal / Q000166:cytology* / Q000378:metabolism; D009924:Organ Culture Techniques; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D011247:Pregnancy; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism; D015017:Yolk Sac / Q000196:embryology* / Q000378:metabolism
D015415:Biomarkers; D019408:Platelet Endothelial Cell Adhesion Molecule-1