Uncoupling Caveolae From Intracellular Signaling In Vivo
Jan R Kraehling1, Zhengrong Hao1, Monica Y Lee1
1From the Vascular Biology and Therapeutics Program (J.R.K., Z.H., M.Y.L., W.C.S.) and Department of Pharmacology (J.R.K., Z.H., M.Y.L., W.C.S.), Yale University School of Medicine, New Haven, CT; Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.); Department of Cell Biology, Yale University, School of Medicine, New Haven, CT (X.L.); and Department of Pathology, Dartmouth Medical School, Lebanon, NH (R.V.S.).
Rationale:
Caveolin-1 (Cav-1) negatively regulates endothelial nitric oxide (NO) synthase-derived NO production, and this has been mapped to several residues on Cav-1, including F92. Herein, we reasoned that endothelial expression of an F92ACav-1 transgene would let us decipher the mechanisms and relationships between caveolae structure and intracellular signaling.
Objective:
This study was designed to separate caveolae formation from its downstream signaling effects.
Methods And Results:
An endothelial-specific doxycycline-regulated mouse model for the expression of Cav-1-F92A was developed. Blood pressure by telemetry and nitric oxide bioavailability by electron paramagnetic resonance and phosphorylation of vasodilator-stimulated phosphoprotein were determined. Caveolae integrity in the presence of Cav-1-F92A was measured by stabilization of caveolin-2, sucrose gradient, and electron microscopy. Histological analysis of heart and lung, echocardiography, and signaling were performed.
Conclusions:
This study shows that mutant Cav-1-F92A forms caveolae structures similar to WT but leads to increases in NO bioavailability in vivo, thereby demonstrating that caveolae formation and downstream signaling events occur through independent mechanisms.
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