Role of endothelial cell-selective adhesion molecule in the regulation of pulmonary vascular resistance

Abstract

Endothelial cell-selective adhesion molecule (ESAM) is a member of the endothelial cell junction adhesion molecules family, which plays an important role in the maintenance of endothelial barrier function in the pulmonary circulation. The role of ESAM in affecting pulmonary vascular resistance remains unknown. To examine the role of ESAM in pulmonary vascular resistance, whole lungs were isolated from 16-18 weeks old ESAM knock out (KO) mice and wild type (WT) littermates, ventilated and perfused. We found that pulmonary vascular resistance is significantly increased in the lung of ESAM KO mice compared to WT mice. Bradykinin-induced, endothelium-dependent reduction in the pulmonary vascular resistance was impaired in ESAM KO mice, whereas the direct NO donor, sodium nitroprusside-induced endothelium independent responses remained similar in WT and ESAM KO mice. U46619 mediated increases in pulmonary vascular resistance was significantly higher in ESAM KO mice. Inhibition of the NO synthesis with the L-NAME (0.2 mM for 10 minutes) augmented the U46619-mediated increase in pulmonary vascular resistance in WT mice, but it did not affect the U46619 response in the ESAM KO mice. The mRNA expression of pro-inflammatory cytokines, including interleukin-6 and tumor necrosis factor, was increased in the lungs of ESAM KO mice, whereas expression of collagen isoforms (type I and type III) and fibronectin were similar in WT and ESAM KO mice. Collectively, we propose that ESAM plays an important role in the maintenance of pulmonary vascular resistance, likely via preserving endothelial nitric oxide production in pulmonary arteries. AHA predoctoral award ID 917057. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.