Figure 2.

Cellular metabolic activity of UVB-irradiated primary human fibroblasts treated with different cell death inhibitors. Prior to UVB irradiation, fibroblasts were incubated 30 min with different cell death inhibitors. Cells were then irradiated in PBS using a lethal UVB dose (30 kJ/m²). The different cell death inhibitors used were: (a) The necroptosis inhibitor Necrosulfonamide (NSA, 2 μM), (b) the ferroptosis inhibitor Ferrostatin-1 (Ferro-1, 5 μM), (c) the broad caspase inhibitor Q-VD-OPh (QVD, 20 μM), (d) the PARP inhibitor ABT888 (ABT, 20 μM) or (e) the PARP inhibitor 3-Aminobenzamide (3-ABA, 0.5 mM). Cellular metabolic activity was assessed at different time points post-UVB irradiation (0, 1, 3, 6, 24 h) using MTS assay. Irradiated cells were normalised on unirradiated cells of the same condition. NSA and Ferro-1 had virtually no effect on cellular metabolism. However, QVD significantly prevent UVB-induced cellular metabolic activity loss at 24 h, ABT at 6 and 24 h and 3-ABA at 3 and 6 h. N = 4. *p-value < 0.05, **p-value < 0.01, ***p-value < 0.001. (f) Efficiency of ABT888 was confirmed by Western Blot, showing an inhibition of PAR formation without abolition of apoptotic PARP cleavage.