Prostacyclin post-treatment improves LPS-induced acute lung injury and endothelial barrier recovery via Rap1.
Biochim Biophys Acta
; 1852(5): 778-91, 2015 May.
Article
en En
| MEDLINE
| ID: mdl-25545047
ABSTRACT
Protective effects of prostacyclin (PC) or its stable analog beraprost against agonist-induced lung vascular inflammation have been associated with elevation of intracellular cAMP and Rac GTPase signaling which inhibited the RhoA GTPase-dependent pathway of endothelial barrier dysfunction. This study investigated a distinct mechanism of PC-stimulated lung vascular endothelial (EC) barrier recovery and resolution of LPS-induced inflammation mediated by small GTPase Rap1. Efficient barrier recovery was observed in LPS-challenged pulmonary EC after prostacyclin administration even after 15 h of initial inflammatory insult and was accompanied by the significant attenuation of p38 MAP kinase and NFκB signaling and decreased production of IL-8 and soluble ICAM1. These effects were reproduced in cells post-treated with 8CPT, a small molecule activator of Rap1-specific nucleotide exchange factor Epac. By contrast, pharmacologic Epac inhibitor, Rap1 knockdown, or knockdown of cell junction-associated Rap1 effector afadin attenuated EC recovery caused by PC or 8CPT post-treatment. The key role of Rap1 in lung barrier restoration was further confirmed in the murine model of LPS-induced acute lung injury. Lung injury was monitored by measurements of bronchoalveolar lavage protein content, cell count, and Evans blue extravasation and live imaging of vascular leak over 6 days using a fluorescent tracer. The data showed significant acceleration of lung recovery by PC and 8CPT post-treatment, which was abrogated in Rap1a(-/-) mice. These results suggest that post-treatment with PC triggers the Epac/Rap1/afadin-dependent mechanism of endothelial barrier restoration and downregulation of p38MAPK and NFκB inflammatory cascades, altogether leading to accelerated lung recovery.
Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Endotelio Vascular
/
Epoprostenol
/
Proteínas de Unión al GTP rap1
/
Lesión Pulmonar Aguda
Tipo de estudio:
Prognostic_studies
Límite:
Animals
/
Humans
Idioma:
En
Año:
2015
Tipo del documento:
Article