title: Internalization of caveolin-1 scaffolding domain facilitated by Antennapedia homeodomain attenuates PAF-induced increase in microvessel permeability.
abstract: We demonstrated previously that inhibition of endothelial nitric oxide synthase (NOS), using pharmacological inhibitors, attenuated the ionomycin- and ATP-induced increases in microvessel permeability (Am J Physiol Heart Circ Physiol 272: H176-H185, 1997). Recently, the scaffolding domain of caveolin-1 (CAV) has been implicated as a negative regulator of endothelial NOS (eNOS). To examine the role of CAV-eNOS interaction in regulation of permeability in intact microvessels, the effect of internalized CAV on the platelet-activating factor (PAF)-induced permeability increase was investigated in rat mesenteric venular microvessels. Internalization of CAV was achieved by perfusion of individual vessels using a fusion peptide of CAV with Antennapedia homeodomain (AP-CAV) and visualized by fluorescence imaging and electron microscopy. Changes in microvessel permeability were evaluated by measuring hydraulic conductivity (Lp) in individually perfused microvessels. We found that the PAF (10 nM)-induced Lp increase was significantly attenuated from 6.0 +/- 0.9 (n = 7) to 2.0 +/- 0.3 (n = 5) times control after microvessels were perfused with 10 microM AP-CAV for 2 h. The magnitude of this reduction is comparable with that of the inhibitory effect of Nomega-monomethyl-l-arginine on the PAF-induced Lp increase. In contrast, perfusion with 10 microM AP alone for 2 h modified neither basal Lp nor the vessel response to PAF. These results indicate that CAV plays an important role in regulation of microvessel permeability. The inhibitory action of CAV on permeability increase might be attributed to its direct inactivation of eNOS. In addition, this study established a method for studying protein-protein interaction-induced functional changes in intact microvessels and demonstrated AP as an efficient vector for translocation of peptide across the cell membrane in vivo.
authors.affiliation: Department of Physiology and Pharmacology, School of Medicine, Health Sciences Center North, West Virginia University, Morgantown, WV 26506-9229, USA.
authors.forename: Longkun
authors.initials: L
authors.lastname: Zhu
authors.forename: Diane
authors.initials: D
authors.lastname: Schwegler-Berry
authors.forename: Vince
authors.initials: V
authors.lastname: Castranova
authors.forename: Pingnian
authors.initials: P
authors.lastname: He
mesh_terms: D000818:Animals; D051943:Antennapedia Homeodomain Protein; D002199:Capillary Permeability / Q000187:drug effects; D051242:Caveolin 1; D022461:Caveolins / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D018398:Homeodomain Proteins / Q000494:pharmacology*; D008833:Microcirculation / Q000187:drug effects; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D009687:Nuclear Proteins; D010972:Platelet Activating Factor / Q000494:pharmacology*; D017434:Protein Structure, Tertiary; D051381:Rats; D017207:Rats, Sprague-Dawley; D013152:Splanchnic Circulation; D014157:Transcription Factors; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D051943:Antennapedia Homeodomain Protein; C495537:Cav1 protein, rat; D051242:Caveolin 1; D022461:Caveolins; D004791:Enzyme Inhibitors; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D010972:Platelet Activating Factor; D014157:Transcription Factors; D019323:omega-N-Methylarginine