Apart from control of circulating fluid,
atrial natriuretic peptide (
ANP) exhibits anti-inflammatory effects in the lung. However, molecular mechanisms of
ANP anti-inflammatory effects are not well-understood. Peripheral microtubule (MT) dynamics is essential for agonist-induced regulation of vascular endothelial permeability. Here we studied the role of MT-dependent signaling in
ANP protective effects against endothelial cell (EC) barrier dysfunction and
acute lung injury induced by Staphylococcus aureus-derived peptidoglican-G (PepG). PepG-induced vascular endothelial dysfunction was accompanied by MT destabilization and disruption of MT network.
ANP attenuated PepG-induced MT disassembly, NFκB signaling and activity of MT-associated Rho activator GEF-H1 leading to attenuation of EC inflammatory activation reflected by expression of adhesion molecules ICAM1 and VCAM1.
ANP-induced EC barrier preservation and MT stabilization were linked to phosphorylation and inactivation of MT-depolymerizing
protein stathmin. Expression of
stathmin phosphorylation-deficient mutant abolished
ANP protective effects against PepG-induced
inflammation and EC permeability. In contrast,
siRNA-mediated
stathmin knockdown prevented PepG-induced peripheral MT disassembly and endothelial barrier dysfunction.
ANP protective effects in a murine model of PepG-induced
lung injury were associated with increased phosphorylation of
stathmin, while exacerbated
lung injury in the
ANP knockout mice was accompanied by decreased pool of stable MT.
Stathmin knockdown in vivo reversed exacerbation of
lung injury in the
ANP knockout mice. These results show a novel MT-mediated mechanism of endothelial barrier protection by
ANP in pulmonary EC and animal model of PepG-induced
lung injury via
stathmin-dependent control of MT assembly.