TY - JOUR T1 - NAD consumption by PARP1 in response to DNA damage triggers metabolic shift critical for damaged cell survival JF - bioRxiv DO - 10.1101/375212 SP - 375212 AU - Michael M. Murata AU - Xiangduo Kong AU - Emmanuel Moncada AU - Yumay Chen AU - Ping Wang AU - Michael W. Berns AU - Kyoko Yokomori AU - Michelle A. Digman Y1 - 2018/01/01 UR - http://biorxiv.org/content/early/2018/08/07/375212.abstract N2 - DNA damage signaling is critical for the maintenance of genome integrity and cell fate decision. Poly(ADP-ribose) polymerase 1 (PARP1) is a DNA damage sensor rapidly activated in a damage dose and complexity-dependent manner playing a critical role in the initial chromatin organization and DNA repair pathway choice at damage sites. However, the cell-wide consequence of its activation in damaged cells is not well delineated. Using the phasor approach to fluorescence lifetime imaging microscopy (FLIM) and fluorescence-based biosensors in combination with laser microirradiation, we found a rapid cell-wide increase of the bound/free NADH ratio in response to nuclear DNA damage, which is triggered by NAD+ depletion by PARP activation. This change is linked to the metabolic balance shift to oxidative phosphorylation (oxphos) over glycolysis. Inhibition of the respiratory chain resulted in rapid PARP-dependent ATP reduction and intracellular acidification, and eventually, PARP-dependent, AIF-independent, apoptosis indicating that oxphos becomes critical for damaged cell survival. The results reveal the novel pro-survival effect of PARP activation through a change in cellular metabolism, and demonstrate how unique applications of advanced fluorescence imaging technologies in combination with laser microirradiation can be a powerful tool to interrogate damage-induced metabolic changes at high spatiotemporal resolution in a live cell. ER -