RESUMO
It has been recently shown that endothelial platelet endothelial cell adhesion molecule-1 (PECAM-1) expression is pro-atherogenic. PECAM-1 is involved in sensing rapid changes in fluid shear stress but the mechanisms for activating signalling complexes at the endothelial cell junction have yet to be elucidated. Additional studies suggest the activation of membrane-bound G proteins G alpha(q/11) also mediate flow-induced responses. Here, we investigated whether PECAM-1 and G alpha(q/11) could act in unison to rapidly respond to fluid shear stress. With immunohistochemistry, we observed a co-localization of G alpha(q/11) and PECAM-1 at the cell-cell junction in the atheroprotected section of mouse aortae. In contrast, G alpha(q/11) was absent from junctions in atheroprone areas as well as in all arterial sections of PECAM-1 knockout mice. In primary human endothelial cells, temporal gradients in shear stress led to a rapid dissociation of the G alpha(q/11)-PECAM-1 complex within 30 s and a partial relocalization of the G alpha(q/11) staining to perinuclear areas within 150 min, whereas transitioning fluid flow devoid of temporal gradients did not disrupt the complex. Inhibition of G protein activation eliminated temporal gradient flow-induced G alpha(q/11)-PECAM-1 dissociation. These results allow us to conclude that G alpha(q/11)-PECAM-1 forms a mechanosensitive complex and its localization suggests the G alpha(q/11)-PECAM-1 complex is a critical mediator of vascular diseases.
Assuntos
Endotélio Vascular/metabolismo , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/metabolismo , Hemorreologia/fisiologia , Mecanotransdução Celular/fisiologia , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Estresse Mecânico , Animais , Aorta/citologia , Aorta/metabolismo , Células Cultivadas , Células Endoteliais/metabolismo , Inibidores Enzimáticos/farmacologia , Guanosina Difosfato/análogos & derivados , Guanosina Difosfato/farmacologia , Humanos , Junções Intercelulares/metabolismo , Espaço Intracelular/metabolismo , Mecanotransdução Celular/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos , Camundongos Knockout , Molécula-1 de Adesão Celular Endotelial a Plaquetas/genética , Ligação Proteica/fisiologia , Transporte Proteico/efeitos dos fármacos , Transporte Proteico/fisiologia , Tionucleotídeos/farmacologiaRESUMO
Abuse of the dissociative anesthetic ketamine can lead to a syndrome indistinguishable from schizophrenia. In animals, repetitive exposure to this N-methyl-d-aspartate-receptor antagonist induces the dysfunction of a subset of cortical fast-spiking inhibitory interneurons, with loss of expression of parvalbumin and the gamma-aminobutyric acid-producing enzyme GAD67. We show here that exposure of mice to ketamine induced a persistent increase in brain superoxide due to activation in neurons of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Decreasing superoxide production prevented the effects of ketamine on inhibitory interneurons in the prefrontal cortex. These results suggest that NADPH oxidase may represent a novel target for the treatment of ketamine-induced psychosis.