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Defects in caveolin-1 cause dilated cardiomyopathy and pulmonary hypertension in knockout mice
You-Yang Zhao1, Yang Liu, Radu-Virgil Stan
1University of California at San Diego, Institute of Molecular Medicine, 9500 Gilman Drive, BSB 0623, La Jolla, CA 92093, USA.
Abstract:
Caveolins are important components of caveolae, which have been implicated in vesicular trafficking and signal transduction. To investigate the in vivo significance of Caveolins in mammals, we generated mice deficient in the caveolin-1 (cav-1) gene and have shown that, in the absence of Cav-1, no caveolae structures were observed in several nonmuscle cell types. Although cav-1(-/-) mice are viable, histological examination and echocardiography identified a spectrum of characteristics of dilated cardiomyopathy in the left ventricular chamber of the cav-1-deficient hearts, including an enlarged ventricular chamber diameter, thin posterior wall, and decreased contractility. These animals also have marked right ventricular hypertrophy, suggesting a chronic increase in pulmonary artery pressure. Direct measurement of pulmonary artery pressure and histological analysis revealed that the cav-1(-/-) mice exhibit pulmonary hypertension, which may contribute to the right ventricle hypertrophy. In addition, the loss of Cav-1 leads to a dramatic increase in systemic NO levels. Our studies provided in vivo evidence that cav-1 is essential for the control of systemic NO levels and normal cardiopulmonary function.
Insights
Mice lacking caveolin-1 (cav-1) developed dilated cardiomyopathy and pulmonary hypertension. This study shows cav-1 is vital for controlling nitric oxide levels and maintaining heart and lung function in vivo.
Area of Science:
- Cardiovascular Biology
- Cell Biology
- Physiology
Background:
- Caveolins are key proteins in caveolae, cellular structures involved in transport and signaling.
- The in vivo role of caveolin-1 (cav-1) in mammalian physiology remains incompletely understood.
Purpose of the Study:
- To investigate the physiological significance of caveolin-1 in vivo.
- To determine the effects of caveolin-1 deficiency on cardiovascular and pulmonary function.
Main Methods:
- Generation and analysis of caveolin-1 knockout (cav-1-/-) mice.
- Histological examination of cardiac and pulmonary tissues.
- Echocardiography to assess cardiac function.
- Direct measurement of pulmonary artery pressure.
- Quantification of systemic nitric oxide (NO) levels.
Main Results:
- Absence of caveolae structures in nonmuscle cells of cav-1-/- mice.
- Development of dilated cardiomyopathy in cav-1-/- mice, characterized by enlarged left ventricle and reduced contractility.
- Significant right ventricular hypertrophy and pulmonary hypertension in cav-1-/- mice.
- Marked elevation of systemic nitric oxide (NO) levels in cav-1-/- mice.
Conclusions:
- Caveolin-1 is essential for maintaining normal cardiopulmonary function in vivo.
- Loss of cav-1 leads to pulmonary hypertension and cardiac dysfunction.
- Caveolin-1 plays a critical role in regulating systemic nitric oxide levels.