Papel do receptor canabinóide CB2 e sua relação com a NNOS no reparo endotelial e remodelamento vascular

Abstract

Studies with cell, animal, and human models consistently demonstrate that current surgical and antiproliferative therapies delay, but do not prevent, hyperplasia of the media and intima arterial layers, regardless of associated dyslipidemia. On the other hand, despite the unquestionable success of current hypocholesterolemic therapy, several studies suggest that the endocannabinoid system may represent an important target for therapeutic action in vascular fibroproliferative diseases. Thus, we tested the hypothesis that the activation of the cannabinoid type 2 (CB2) receptors could modulate the neuronal nitric oxide synthase (nNOS) enzyme and prevent the damage caused in a carotid occlusion model in C57BL6J mice. The carotid artery was occluded under local treatment with CB2-JWH015 agonist. The carotid was evaluated by histological techniques and also by fluorescence microscopy (immunofluorescence and NO-sensitive fluorescent probes and superoxide radicals). Human endothelial cells were also exposed to treatment with the same agonist. In this model, protein expression (eNOS, nNOS, proliferation markers and CB2 receptors), NO and superoxide production and cell migration were evaluated. The results showed that the CB2 agonist prevents neointima formation in the model studied, with reduction in the density of endothelial cells, collagen, matrix metalloproteinase and superoxide radicals. In endothelial cells, treatment with JWH015 increases nNOS expression and NO production. Inhibition of nNOS leads to a decrease in superoxide, indicating that this isoform may be uncoupled. Under oscillatory shear stress (OSS), we observed that both the JWH015 stimulus and the nNOS inhibition lead to a decrease in NO production, which appears to be triggered by the activation of the PI3K / AKT pathway. On endothelial healing (slit assay), we found that CB2 receptor agonist treatment reduced the time to closure of the slit at rest. On the other hand, inhibition of the nNOS enzyme delayed this process. We conclude that for the CB2 receptor to be used as a pharmacological target for the prevention of neointima formation, more trials need to be developed in biological models.