A. Denicola - Oxidative stress, ROS, and the role of peroxiredoxins

Ana Denicola, Laboratory of Physical Biochemistry, Chemical Biology Institute, School of Sciences, University of the Republic, URUGUAY speaks on "Oxidative stress, ROS, and the role of peroxiredoxins".
Abstract:
There is ample evidence that oxidative stress is associated with several pathologies including cancer, neurodegenerative and cardiovascular diseases, as well as with aging. Oxidative stress was first defined in 1991 by Helmut Sies as “the perturbation of the pro-antioxidant balance in favor of the former, yielding cellular damage”. Since the appearance of oxygen into the atmosphere by O2-evolving photosynthetic organisms, ROS (Reactive Oxygen Species) have been the unwelcome companions of aerobic metabolism, and aerobic organisms evolved by expressing a wide variety of antioxidants (enzymes and low molecular weight antioxidants). The term “ROS” is frequently used in the literature to gather biological oxidants. ROS is not a unique chemical species but a diverse group of molecules, some are free radicals and strong oxidants, but some are not so reactive. Even more, some ROS could trigger a physiological response and not cellular damage. The concept of oxidative stress has changed. In 2017, Helmut Sies defined oxidative eustress as the “physiological oxidative challenge, essential for redox signaling”. Hydrogen peroxide (H2O2) has emerged as a second messenger in redox signaling via oxidation of critical cysteine residues in redox proteins. Peroxiredoxins (Prx) are a family of thiol-dependent peroxidases that efficiently reduce hydroperoxides. The fast reaction of H2O2 with the peroxidatic cysteine at the active site of Prx gives specificity to the H2O2-mediated redox signal. Our studies focus on the biophysical characterization of Prx that contributes to understanding their role in redox signaling.response and not cellular damage. The concept of oxidative stress has changed. In 2017, Helmut Sies defined oxidative eustress as the “physiological oxidative challenge, essential for redox signaling”. Hydrogen peroxide (H2O2) has emerged as a second messenger in redox signaling via oxidation of critical cysteine residues in redox proteins. Peroxiredoxins (Prx) are a family of thiol-dependent peroxidases that efficiently reduce hydroperoxides. The fast reaction of H2O2 with the peroxidatic cysteine at the active site of Prx gives specificity to the H2O2-mediated redox signal. Our studies focus on the biophysical characterization of Prx that contributes to understanding their role in redox signaling.