title: Caveolin-1 siRNA increases the pulmonary microvascular and alveolar epithelial permeability in rats.
abstract: BACKGROUND
  Increased pulmonary microvascular and epithelial permeability are important contributors to pulmonary edema in acute lung injury. In this study, we used small interfering RNA (siRNA) to knock down caveolin-1 expression in rat lungs and to confirm the important role of caveolin-1 in regulating pulmonary edema.
  
  
  METHODS
  After pulmonary injection of siRNA against caveolin-1 messenger RNA incorporated in liposomes with three concentrations of 0.4, 0.8, and 1.2 mg/kg, the gene silencing rate and the effects of caveolin-1 siRNA on aquaporin (AQP)-1, AQP-5, and epithelial sodium channel (ENaC) were detected. For pulmonary permeability analysis, Evans blue fluorimetry, ratios of albumin concentrations between blood and bronchoalveolar lavage, and wet/dry weight ratios were measured. The impacts of caveolin-1 suppression on interendothelial junctions were evaluated by the performance of electron microscopy and the analysis of vascular endothelial (VE)-cadherin Western blot. Alveolar wall thickness analysis and chest fluoroscopy were performed to determine the pulmonary edema degree.
  
  
  RESULTS
  After 72 hours of injection, the gene silencing rate of caveolin-1 siRNA is about 87%. AQP-1, AQP-5, ENaC-α, ENaC-β, ENaC-γ, and VE-cadherin protein levels were decreased by 63%, 66%, 80%, 90%, 89%, and 50%, respectively. Caveolin-1 siRNA also resulted in increasing microvascular and epithelial permeability and pulmonary edema.
  
  
  CONCLUSIONS
  These data suggest that caveolin-1 plays an important part in regulating the pulmonary permeability by modifying AQP-1, AQP-5, ENaC, and VE-cadherin.
authors.affiliation: Department of Burn and Plastic Surgery, Rui Jin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China.
authors.forename: Chengjin
authors.initials: C
authors.lastname: Gao
authors.forename: Rongrong
authors.initials: R
authors.lastname: Li
authors.forename: Jingning
authors.initials: J
authors.lastname: Huan
authors.forename: Wei
authors.initials: W
authors.lastname: Li
mesh_terms: D000818:Animals; D051398:Aquaporin 1 / Q000096:biosynthesis; D051402:Aquaporin 5 / Q000096:biosynthesis; D015153:Blotting, Western; D002199:Capillary Permeability / Q000502:physiology*; D051242:Caveolin 1 / Q000235:genetics* / Q000502:physiology; D053503:Epithelial Sodium Channels / Q000096:biosynthesis; D005070:Evans Blue; D005470:Fluorometry; D020868:Gene Silencing / Q000502:physiology; D008297:Male; D055806:Microvessels / Q000502:physiology* / Q000648:ultrastructure; D011650:Pulmonary Alveoli / Q000098:blood supply* / Q000502:physiology / Q000648:ultrastructure; D034741:RNA, Small Interfering / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020545:Respiratory Mucosa / Q000098:blood supply / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: C496040:Aqp5 protein, rat; D051402:Aquaporin 5; D051242:Caveolin 1; D053503:Epithelial Sodium Channels; D034741:RNA, Small Interfering; D051398:Aquaporin 1; D005070:Evans Blue