Journal: American Journal of Physiology - Lung Cellular and Molecular Physiology
Article Title: High-molecular-weight hyaluronan is a novel inhibitor of pulmonary vascular leakiness
doi: 10.1152/ajplung.00405.2009
Figure Lengend Snippet: Analysis of CD44 and caveolin-1 regulation of high-molecular-weight hyaluronan (HMW-HA) binding to human pulmonary endothelial cells (EC). A: EC were grown to confluency and serum-starved for 1 h, and Triton X-100-soluble, Triton X-100-insoluble, and OptiPrep fractions were prepared. The 20% OptiPrep fraction represents the caveolin-enriched microdomain (CEM) fraction. Fractions were run on SDS-PAGE, transferred to nitrocellulose, and immunoblotted with anti-caveolin-1 (a), anti-fibrillarin (b), anti-cyclooxygenase (COX) IV (c), anti-lysosomal-associated membrane glycoprotein 2 precursor (LAMP2b, d), anti-Golgi reassembly stacking protein 65 (GRASP65, e), or anti-VEGF receptor (anti-VEGFR, f). B: EC were grown to confluency, serum-starved for 1 h, and either left untreated (control) or treated with 100 nM HMW-HA (5 min) or the CEM-abolishing cholesterol-depletion agent methyl-β-cyclodextrin (MβCD, 5 mM) for 1 h prior to 100 nM HMW-HA treatment (5 min). Cellular material was solublized in 4°C 1% Triton X-100, and soluble and insoluble fractions were obtained. Triton X-100-insoluble fraction was overlaid with 60%, 40%, 30%, and 20% OptiPrep and centrifuged at 35,000 rpm in an SW60 rotor for 12 h at 4°C. Triton X-100-soluble material and OptiPrep fractions were run on SDS-PAGE, transferred to nitrocellulose, and immunoblotted with anti-caveolin-1 (a), anti-CD44s (IM-7, standard domain, b), or anti-VEGF receptor 2 (anti-VEGFR2, c) antibody. The 20% OptiPrep fraction is the CEM fraction. Experiments were performed in triplicate, with highly reproducible findings, and representative data are shown. C: immunoblot analysis of small interfering RNA (siRNA)-treated or untreated human EC. Cellular lysates from untransfected (control, no siRNA), scramble siRNA (siRNA that does not target any known human mRNA), caveolin-1 siRNA, or CD44 siRNA transfection were analyzed using immunoblotting with anti-caveolin-1 (a), anti-CD44 (IM-7, b), or anti-actin (c) antibody. Experiments were performed in triplicate, each with similar results, and representative data are shown. D: quantitation of fluorescein-conjugated HMW-HA binding to scramble siRNA-, annexin A11 siRNA-, CD44 siRNA-, or caveolin-1 siRNA-treated EC. Fluorescein-conjugated HMW-HA (100 nM) was added for 15 min to EC in serum-free medium, cells were washed 3 times in serum-free medium, and fluorescence intensity was quantified. Cells were counted utilizing a hemocytometer.
Article Snippet: The 20% OptiPrep fraction represents the caveolin-enriched microdomain (CEM) fraction.
Techniques: High Molecular Weight, Binding Assay, SDS Page, Membrane, Control, Western Blot, Small Interfering RNA, Transfection, Quantitation Assay, Fluorescence