Fig. 1.

PARP activation induces defects in glycolysis. (A) Western blots showing PAR formation in cortical neurons after treatment for 15 min with MNNG (50 μM). DPQ (30 μM) inhibits MNNG-induced PAR formation. (B) Cell-death assessment in mouse cortical neurons treated with MNNG ± DPQ. Cell death was assessed using propidium iodide and Hoechst staining. n = 6; *P < 0.01 vs. control. (C) ECAR analysis in MNNG-treated cortical neurons. Cortical neurons were treated with MNNG for 15 min; then medium was replaced with glucose-free Seahorse medium for ECAR analysis. n = 6; *P < 0.01 vs. control. (D) Basal ECAR was calculated relative to the DMSO control. After the nonglycolytic ECAR was subtracted, the basal ECAR was 20.97 ± 4.2, 10.15 ± 1.5, and 20.34 ± 3.4 milli-pH (mpH)⋅min⁻¹⋅100 µg protein⁻¹ for DMSO-, MNNG-, and MNNG + DPQ-treated cultures, respectively. n = 6; *P < 0.01 vs. control. (E) Maximal glycolysis after the addition of oligomycin was calculated relative to DMSO control. After the nonglycolytic ECAR was subtracted, the maximal ECAR was 34.36 ± 4.6, 10.2 ± 1.5, and 25.10 ± 2.4 mpH⋅min⁻¹⋅100 µg protein⁻¹ in DMSO-, MNNG-, and MNNG + DPQ-treated cultures, respectively. n = 6; *P < 0.01 vs. control. (F) Glycolytic reserve capacity in cortical neurons treated with MNNG ± DPQ. After the nonglycolytic ECAR was subtracted, the reserve ECAR was 13.39 ± 2.7, 1.05 ± 1.3, and 5.87 ± 2.5 mpH⋅min⁻¹⋅100 µg protein⁻¹ in DMSO-, MNNG-, and MNNG + DPQ-treated cultures, respectively. n = 6; *P < 0.05 vs. control. (G) Lactate production in cortical neurons treated with MNNG ± DPQ. PARG cultures were transduced with adenovirus expressing PARG on DIV 10 and were treated with MNNG on DIV 12. Lactate was measured in the medium 1 h after MNNG treatment. n = 4; *P < 0.05 vs. control. Data represent mean ± SEM.