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Biochem Biophys Res Commun. 2010 Feb 12;392(3):264-70. doi: 10.1016/j.bbrc.2009.12.161. Epub 2010 Jan 10.

PARP-1 inhibition does not restore oxidant-mediated reduction in SIRT1 activity.

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  • 1Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY, USA.


Sirtuin1 (SIRT1) deacetylase and poly(ADP-ribose)-polymerase-1 (PARP-1) respond to environmental cues, and both require NAD(+) cofactor for their enzymatic activities. However, the functional link between environmental/oxidative stress-mediated activation of PARP-1 and SIRT1 through NAD(+) cofactor availability is not known. We investigated whether NAD(+) depletion by PARP-1 activation plays a role in environmental stimuli/oxidant-induced reduction in SIRT1 activity. Both H(2)O(2) and cigarette smoke (CS) decreased intracellular NAD(+) levels in vitro in lung epithelial cells and in vivo in lungs of mice exposed to CS. Pharmacological PARP-1 inhibition prevented oxidant-induced NAD(+) loss and attenuated loss of SIRT1 activity. Oxidants decreased SIRT1 activity in lung epithelial cells; however increasing cellular NAD(+) cofactor levels by PARP-1 inhibition or NAD(+) precursors was unable to restore SIRT1 activity. SIRT1 was found to be carbonylated by CS, which was not reversed by PARP-1 inhibition or selective SIRT1 activator. Overall, these data suggest that environmental/oxidant stress-induced SIRT1 down-regulation and PARP-1 activation are independent events despite both enzymes sharing the same cofactor.

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