Premium
Apical secretion of collagen II from endothelial cells precedes blood vessel formation during postnatal vasculogenesis
Author(s) -
Alvarez Diego F.,
Robinson Daniel,
ElZarrad M. Khair,
Stevens Troy,
King Judy A.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1178.13
Subject(s) - vasculogenesis , vacuolization , lumen (anatomy) , endothelium , microbiology and biotechnology , blood vessel , matrix (chemical analysis) , endothelial stem cell , biology , chemistry , pathology , anatomy , medicine , endocrinology , stem cell , in vitro , biochemistry , chromatography , progenitor cell
Postnatal vasculogenesis requires lumen formation during vessel development. Conflicting studies suggest that endothelial vacuolization or inside‐out matrix deposition initiates lumen formation. Since adult pulmonary microvascular endothelial cells (PMVECs) are highly vasculogenic, we sought to determine the mechanism resulting in lumen formation during PMVEC‐mediated postnatal vasculogenesis. GFP‐transfected PMVECs were mixed with matrix gel, injected subcutaneously in rats, excised within 10 days, and processed for microscopy (n=5 each). After 2 days post‐implantation, PMVECs formed clusters of 4 to 6 cells (stage 1) with some clusters displaying apical matrix deposits (stage 2). After 4 days, lumens contained either matrix (stage 3) or blood cells (stage 4). After 10 days, a predominance of blood vessels (stage 4) was observed. There was no evidence of endothelial vacuolization at any time point. By transmission microscopy, the apical matrix deposits were identified as collagen. Liposomal transfection of quantum dots in PMVECs revealed apical secretion of the dots by this phenotype during stage 2. GFP‐PMVECs within the gel were involved in all stages described, and collagen II was identified as the isoform present in the apical structures during stages 2 and 3. We conclude that endothelial apical secretion of collagen II precedes blood vessel formation during postnatal vasculogenesis. HL66299.