Figure 5.

SIRT3 deficiency enhances AEC mtDNA damage and apoptosis after exposure to oxidative stress. A549 cells were transiently transfected with siRNA that was targeted to SIRT3 (si-SIRT3) or a universal scramble negative control (scramble) using RNAiMax for 48 h, then cells were exposed to asbestos (25 µg/cm²) or H₂O₂ (250 µM) for 24 h. A) SIRT3, MnSOD^K68, CC-9, and GAPDH in total cell lysate were assessed by Western blot. B) Shown is a representative blot from a total of 3 experiments that were assessed by a densitometric analysis of the CC-9/GAPDH and MnSOD^K68/GAPDH expression normalized to untreated controls. C, D) MtDNA damage (C) and DNA fragmentation (D) were measured after 24 h of oxidant stress as described; n = 3 for both. *P < 0.05 vs. control [no treatment (NT)], ⁺P < 0.05 vs. scramble.