Physiologic Consequences of Caveolin-1 Ablation in Conventional Outflow Endothelia.
De Ieso Michael L, Gurley Jami M, McClellan Mark E, Gu Xiaowu, Navarro Iris, Li Guorong, Gomez-Caraballo Maria, Enyong Eric, Stamer W Daniel, Elliott Michael H
AI Summary
Targeting endothelial Cav1 in mice elevated eye pressure, linking its absence to eNOS hyperactivity and dilated drainage vessels, but not outflow facility reduction, suggesting a specific role beyond conventional outflow resistance.
Abstract
Purpose
Polymorphisms at the caveolin-1/2 locus are associated with glaucoma and IOP risk and deletion of caveolin-1 (Cav1) in mice elevates IOP and reduces outflow facility. However, the specific location/cell type responsible for Cav1-dependent regulation of IOP is unclear. We hypothesized that endothelial Cav1 in the conventional outflow (CO) pathway regulate IOP via endothelial nitric oxide synthase (eNOS) signaling.
Methods
We created a mouse with targeted deletion of Cav1 in endothelial cells (Cav1ΔEC) and evaluated IOP, outflow facility, outflow pathway distal vascular morphology, eNOS phosphorylation, and tyrosine nitration of iridocorneal angle tissues by Western blotting.
Results
Endothelial deletion of Cav1 resulted in significantly elevated IOP versus wild-type mice but not a concomitant decrease in outflow facility. Endothelial Cav1 deficiency did not alter the trabecular meshwork or Schlemm's canal morphology, suggesting that the effects observed were not due to developmental deformities. Endothelial Cav1 deletion resulted in eNOS hyperactivity, modestly increased protein nitration, and significant enlargement of the drainage vessels distal to Schlemm's canal. L-Nitro-arginine methyl ester treatment reduced outflow in Cav1ΔEC but not wild-type mice and had no effect on the size of drainage vessels. Endothelin-1 treatment decrease the outflow and drainage vessel size in both wild-type and Cav1ΔEC mice.
Conclusions
Our results suggest that hyperactive eNOS signaling in the CO pathway of both Cav1ΔEC and global Cav1 knockout mice results in chronic dilation of distal CO vessels and protein nitration, but that Cav1 expression in the trabecular meshwork is sufficient to rescue CO defects reported in global Cav1 knockout mice.
MeSH Terms
Shields Classification
Key Concepts6
Targeted deletion of Caveolin-1 (Cav1) in endothelial cells (Cav1ΔEC) in mice resulted in significantly elevated intraocular pressure (IOP) compared to wild-type mice.
Endothelial deletion of Caveolin-1 (Cav1) in mice did not result in a concomitant decrease in outflow facility.
Endothelial Caveolin-1 (Cav1) deficiency in mice did not alter the trabecular meshwork or Schlemm's canal morphology.
Endothelial Caveolin-1 (Cav1) deletion in mice resulted in eNOS hyperactivity, modestly increased protein nitration, and significant enlargement of the drainage vessels distal to Schlemm's canal.
L-Nitro-arginine methyl ester treatment reduced outflow in Cav1ΔEC mice but not in wild-type mice and had no effect on the size of drainage vessels.
Endothelin-1 treatment decreased outflow and drainage vessel size in both wild-type and Cav1ΔEC mice.
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