Oxidative Stress Induces HSP90 Upregulation on the Surface of Primary Human Endothelial Cells: Role of the Antioxidant 7,8-Dihydroxy-4-methylcoumarin in Preventing HSP90 Exposure to the Immune System

Figure 5

(a) Analysis of soluble HSP90 concentrations (pg/ml) by ELISA in culture supernatants from HUVEC pretreated with 7,8-dihydroxy-4-methylcoumarin (7,8-DHMC) or diluent alone and then exposed to H₂O₂ or left untreated. Results are expressed as mean and standard error of the mean (). ; . (b) Pearson correlation between the percentages of surface HSP90-positive cells evaluated by cytofluorimetric assay and the concentrations of soluble HSP90 (pg/ml) in culture supernatants determined by ELISA in HUVEC pretreated with 7,8-dihydroxy-4-methylcoumarin (7,8-DHMC) or diluent alone and then exposed to H₂O₂ or left untreated. Pearson correlation was chosen since a Gaussian distribution of the data was observed according to the D’Agostino and Pearson omnibus normality test. The two-phase decay was used to obtain the fit.

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