Аңдатпа
There is evidence that the deposition of amyloid-beta peptide (Aβ) in brain parenchyma and brain vessels is the main cause of neuronal dysfunction in Alzheimer's disease (AD). Aβ exhibits multiple cytotoxic effects to neurons and causes dysfunction of the blood brain barrier (BBB). In the AD brains an increased deposition of Aβ in the cerebral vasculature is correlated with increased transmigration of blood-born inflammatory cells and neurovascular inflammation. However, regulatory mediators of these processes remain to be elucidated. In this study, we examined a role of ROS in actin polymerization and expression of adhesion molecules on the surface of the cerebral endothelial cells (CECs) that are activated by Aβ42. Mouse bEnd3 line (ATCC) was used in this research as following: control; cells incubated with Aβ42 for 10, 30 and 60 min; cells incubated with 30 mM of antioxidant N-acetylcysteine (NAC) for 1 hr; cells pretreated with NAC followed by Aβ42 exposure. To investigate intracellular ROS production, we measured DHE fluorescence. Immunofluorescent microscopy of anti-P-selectin, and Oregon green phalloidin was used to quantify the surface P-selectin expression and actin polymerization, and W estern blot was applied for total P-selectin expression. We demonstrated significant time-dependent ROS accumulation after 10-60 min of Aβ42 treatment in CECs, while pretreatment with the antioxidant NAC attenuated this process. We also found that Aβ42 increased P-selectin fluorescence at the surface of bEnd3 cells in a time dependent manner and in parallel to ROS elevation. At the time, pretreatment with NAC attenuated Aβ42 induced P-selectin translocation. However, total expression levels of P-selectin were not changed following exposure to Aβ42. Exposure of CECs with Aβ42 promoted actin polymerization which peaked after 10 min of Aβ42 treatment, while no significant increase of F-actin intensity was observed when cells were pretreated with NAC. As a positive control, H 2 O 2 was able to mimic Aβ42 induced oxidative stress, causing increased P-selectin expression on the cell surface and actin polymerization with similar timing. The results of our study have indicated that Aβ42 induces accumulation of P-selectin on the surface of bEnd3 cells and promotes actin polymerization through ROS - dependent cell signaling pathways.