Fig. 4. Lipoic acid and lipoamide reduce stress granule formation in cells.

a Immunofluorescence detection of the stress granule marker G3BP1 in A549 cancer cells. Stress granules appear as red foci in the DMSO control and cells treated with (HDAC-inactive) (S)-LA. The reduction of defined stress granules in response to (R)-LA and (R/S)-LA is apparent from the blurred red areas. b Quantification of the number of stress granules per cell. Each treatment was performed in n = 3 independent biological experiments and between 140 and 150 cells were submitted to stress granule counting. c Levels of oxidative stress induced by 2 h treatment with 200 µM Tertbutylhydroperoxide (BuOOH) after 1 h pre-treatment with drugs (Vor Vorinostat, NAC N-acetylcysteine) in A549 cells. Oxidative stress levels were assessed using the CellRox assay. Every data point corresponds to one biological replicate and is the mean CellRox intensity from 9 to 10 pictures capturing 60–180 cells in total (n = 2 biologically independent samples for 100 µM (S)-LA, n = 3 biologically independent samples for all other treatments, AU arbitrary units). d Levels of oxidative stress in A549 cells after 1.5 h drug pre-treatment, optionally followed by a 30 min arsenite (1 mM) pulse. Oxidative stress levels were assessed using the CellRox assay. Every data point corresponds to one biological replicate and equals the mean CellRox intensity from 10 to 15 pictures capturing 60–180 cells in total (n = 3 biologically independent samples for each drug dose, AU arbitrary units). b–d Statistical significance was calculated between the control and drug pre-treatments by one-way ANOVA following the Dunnett test for multiple comparisons using the GraphPad Prism software. Data are presented as means ± SD. ns not significant, ***P-value ≤ 0.001, **P-value ≤ 0.01, *P-value ≤ 0.05 in one-way ANOVA after Dunnett’s multiple comparison test). Source data are provided as a Source Data file.