Figure 6.

Aβ₄₂ alters cellular redox parameters and does not activate Src kinase in hypoxic conditions. (A,B) The effect of Aβ₄₂ on the levels of reactive oxygen species (ROS). (C,D) The oxidized glutathione/reduced glutathione (GSSG/GSH) ratio. (E,F) Reduced glutathione (GSH), and (G,H) Ca²⁺ levels in the SH-SY5Y human neuroblastoma cells. The cells were harvested, stained with fluorescent probes: Dyhydrorhodamine 123 for ROS measurements, ThiolTracker Violet for GSH measurements, and Fluo-4 for Ca²⁺ levels measurements and incubated with 100 nM Aβ₄₂ for 10 min (A,C,E,G) or for 30 min (Β,D,F,H). The GSSG/GSH ratio was determined with Grx1-roGFP genetically encoded ratiometric sensor. The change in the GSSG/GSH ratio was determined by calculating the ratio of the fluorescence intensity values at a wavelength of 535 nm, obtained with excitation at the wavelengths of 488 and 400 nm. All parameters were normalized for control. (I,J) The ratio of phospho(Tyr-416)-Src to total Src in SH-SY5Y neuroblastoma cells incubated with 100 nM of Aβ₄₂ for 30 min under hypoxic conditions (1% O₂) and standard conditions (20% O₂) determined with Western blot. (I) The representative blot, and (J) the corresponding p-Src/Src ratio are presented. Mean values ± SD from at least three independent experiments are shown. *—p <0.05, **—p <0.01 compared to the control, ns—nonsignificant.