The alpha-isoform of caveolin-1 is a marker of vasculogenesis in early lung development.
Caveolin-1 is a scaffolding protein component of caveolae, membrane invaginations involved in endocytosis, signal transduction, trans- and intracellular trafficking, and protein sorting. In adult lung, caveolae and caveolin-1 are present in alveolar endothelium and Type I epithelial cells but rarely in Type II cells. We have analyzed patterns of caveolin-1 expression during mouse lung development. Two caveolin-1 mRNAs, full-length and a 5' variant that will translate mainly into caveolin-1alpha and -beta isoforms, are detected by RT-PCR at embryonic day 12 (E12) and afterwards in the developing and adult lung. Immunostaining analysis, starting at E10, shows caveolin-1alpha localized in primitive blood vessels of the forming lung, in an overlapping pattern to the endothelial marker PECAM-1, and later in all blood vessels. Caveolin-1alpha is not detected in fetal or neonatal lung epithelium but is detected in adult epithelial Type I cells. Caveolin-1 was previously shown to be expressed in alveolar Type I cells. These data suggest that expression of caveolin-1 isoforms is differentially regulated in endothelial and epithelial cells during lung development. Caveolin-1alpha is an early marker for lung vasculogenesis, primarily expressed in developing blood vessels. When the lung is fully differentiated postnatally, caveolin-1alpha is also expressed in alveolar Type I cells.
Ramirez
Maria I
MI
Pulmonary Center, Departments of Medicine, Boston University School of Medicine, Boston, MA 02118, USA. mramirez@lung.bumc.bu.edu
Pollack
Lee
L
Millien
Guetchyn
G
Cao
Yu Xia
YX
Hinds
Anne
A
Williams
Mary C
MC
D000818:Animals; D000831:Animals, Newborn; D015415:Biomarkers; D001808:Blood Vessels / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism*; D015153:Blotting, Western; D051242:Caveolin 1; D022461:Caveolins / Q000235:genetics / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D004848:Epithelium / Q000254:growth & development / Q000378:metabolism; D005865:Gestational Age; D007150:Immunohistochemistry; D008168:Lung / Q000098:blood supply* / Q000196:embryology / Q000254:growth & development*; D051379:Mice; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D020033:Protein Isoforms; D011650:Pulmonary Alveoli / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D015415:Biomarkers; C495541:Cav1 protein, mouse; D051242:Caveolin 1; D022461:Caveolins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D020033:Protein Isoforms; D012333:RNA, Messenger