Caveolae-deficient Endothelial Cells Show Defects in the Uptake and Transport of Albumin in Vivo

William Schubert, Philippe G. Frank, Babak Razani, David S. Park, Chi Wing Chow, Michael P. Lisanti

Research output: Contribution to journalArticle

244 Scopus citations

Abstract

The role of endothelial cell caveolae in the uptake and transport of macromolecules from the blood-space to the tissue-space remains controversial. To address this issue directly, we employed caveolin-1 gene knock-out mice that lack caveolin-1 protein expression and caveolae organelles. Here, we show that endothelial cell caveolae are required for the efficient uptake and transport of a known caveolar ligand, i.e. albumin, in vivo. Caveolin-1-null mice were perfused with 5-nm gold-conjugated albumin, and its uptake was followed by transmission electron microscopy. Our results indicate that gold-conjugated albumin is not endocytosed by Cav-1-deficient lung endothelial cells and remains in the blood vessel lumen; in contrast, gold-conjugated albumin was concentrated and internalized by lung endothelial cell caveolae in wild-type mice, as expected. To quantitate this defect in uptake, we next studied the endocytosis of radioiodinated albumin using aortic ring segments from wild-type and Cav-1-null mice. Interestingly, little or no uptake of radioiodinated albumin was observed in the aortic segments from Cav-1-deficient mice, whereas aortic segments from wild-type mice showed robust uptake that was time- and temperature-dependent and competed by unlabeled albumin. We conclude that endothelial cell caveolae are required for the efficient uptake and transport of albumin from the blood to the interstitium.

Original languageEnglish (US)
Pages (from-to)48619-48622
Number of pages4
JournalJournal of Biological Chemistry
Volume276
Issue number52
DOIs
StatePublished - Dec 28 2001

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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    Schubert, W., Frank, P. G., Razani, B., Park, D. S., Chow, C. W., & Lisanti, M. P. (2001). Caveolae-deficient Endothelial Cells Show Defects in the Uptake and Transport of Albumin in Vivo. Journal of Biological Chemistry, 276(52), 48619-48622. https://doi.org/10.1074/jbc.C100613200