A nuclear-localized fluorescent hydrogen peroxide probe for monitoring sirtuin-mediated oxidative stress responses in vivo.

Hydrogen peroxide (H(2)O(2)) can serve as a beneficial signaling agent or toxin depending on its concentration and location within a cell or organism. Methods to measure the localized accumulation of H(2)O(2) in living specimens remain limited. Motivated to meet this need, we have developed a nuclear-localized fluorescent probe for H(2)O(2), Nuclear Peroxy Emerald 1 (NucPE1), to selectively interrogate ROS fluxes within this sensitive organelle. NucPE1 selectively accumulates in the nuclei of a variety of mammalian cell lines as well as in whole model organisms like Caenorhabditis elegans, where it can respond to subcellular changes in H(2)O(2) fluxes. Moreover, in vivo NucPE1 imaging reveals a reduction in nuclear H(2)O(2) levels in worms overexpressing sir-2.1 compared with wild-type congeners, supporting a link between this longevity-promoting sirtuin protein and enhanced regulation of nuclear ROS pools.