Figure 5.

Evaluation of lysosomal pH in patient-derived fibroblasts. (A) Representative images of fibroblasts incubated with LysoSensor yellow/blue dextran and visualized in live at 340 and 380 nm excitation. White lines represent cells detected in bright field and used as regions of interest for intensity measurement. Scale bar = 10 µm. (B) The calibration curve, obtained by plotting the fluorescence intensity 380/340 ratios as a function of pH, was fitted with linear regression. Data are means ± SEM from the five cells shown in A. (C) pH value derived from 340/380 ratio and relative calibration curve. Each dot represents the mean pH from a single coverslip. 5–14 coverslips have been analysed for each experimental group with an average of 14 cells analysed for each coverslip. *P ≤ 0.001; **P ≤ 0.0001 unpaired Student’s t-test/Mann–Whitney U-test.