Imbalance of caveolin-1 and eNOS expression in the pulmonary vasculature of experimental diaphragmatic hernia.

[congenital diaphragmatic hernia]

Caveolin-1 (Cav-1 ) exerts major regulatory functions on intracellular signaling pathways originating at the plasma membrane . Cav-1 is a key regulator in adverse lung remodeling and the development of pulmonary hypertension (PH ) regulating vasomotor tone through its ability to reduce nitric oxide (NO ) production . This low -output endothelial NO synthase (eNOS ) derived NO maintains normal pulmonary vascular homeostasis . Cav-1 deficiency leads to increased bioavailability of NO , which has been linked to increased nitrosative stress . Inhibition of eNOS reduced oxidant production and reversed PH , supporting the concept that Cav-1 regulation of eNOS activity is crucial to endothelial homeostasis in lungs . We designed this study to investigate the hypothesis that expression of Cav-1 is downregulated while eNOS expression is upregulated by the pulmonary endothelium in the nitrofen-induced congenital diaphragmatic hernia (CDH ).Pregnant rats were exposed to nitrofen or vehicle on day 9 .5 (D 9 .5 ). Fetuses were sacrificed on D 21 and divided into nitrofen and control groups . Quantitative real-time polymerase chain reaction , Western blotting , and confocal immunofluorescence were performed to determine pulmonary gene expression levels and protein expression of Cav-1 and eNOS .Pulmonary Cav-1 gene expression levels were significantly decreased , while eNOS gene expression was significantly increased in nitrofen-induced CDH (+). Western blotting and confocal microscopy revealed decreased pulmonary Cav-1 protein expression , while eNOS protein expression was increased in CDH (+) compared to controls .The striking evidence of markedly decreased gene and protein expression of Cav-1 with concurrently increased eNOS gene and protein expression in the pulmonary vasculature suggests that activation of eNOS secondary to Cav-1 deficiency may play an important role in the pathogenesis of PH in the nitrofen-induced CDH .