Trying to bring some order to chaos FUNDAMENTAL AND EMERGING CONCEPTS IN THE REDOX REGULATION OF EXERCISE RESPONSES AND ADAPTATIONS Trying to bring some order to chaos Michalis G. Nikolaidis Department of Physical Education and Sports Science (Serres) Aristotle University of Thessaloniki Greece nikolaidis@auth.gr nikolaidis.weebly.com

Trying to bring some order to chaos

F C I I would argue for: FUNDAMENTALITY of redox reactions in biology COMPLEXITY of reactive species metabolism INVOLVEMENT of reactive species in exercise responses and adaptations I

F C I I would argue for: F C I FUNDAMENTALITY of redox reactions in biology C COMPLEXITY of reactive species metabolism INVOLVEMENT of reactive species in exercise responses and adaptations I

F C I I would argue for: F C I FUNDAMENTALITY of redox reactions in biology C COMPLEXITY of reactive species metabolism INVOLVEMENT of reactive species in exercise responses and adaptations I

F C I I would argue for: F C I FUNDAMENTALITY of redox reactions in biology C COMPLEXITY of reactive species metabolism INVOLVEMENT of reactive species in exercise responses and adaptations I

Heterogeneity of reactive species s to min min OH• O2•- ROO• NO• HClO H2O2 Increasing half life

Heterogeneity of antioxidants C I SOD_3 VC SOD_1 VC SOD_2 VC SOD_1 VC Cell

Architectural and functional specificity of redox metabolism

Cell signaling via redox molecules F C I H2O2 Prx-2red STAT3ox Redox signaling H2O Prx-2ox STAT3red H2O2 Target protein H2O2 Redox signaling H2O Random oxidations H2O2 Oxidative stress Prx-2overox (inactive)

Responses/adaptations to oxidative stress F C I Plasma membrane MDA Ryanodine receptor Ca2+ Sarcoplasmic reticulum Place et al. PNAS 112:15492, 2015

Exercise produces reactive species F C I O2 − ecSOD H2O2 XO Endothelium Plasma membrane nNOS NADPH oxidase T-tubule O2 − NADPH oxidase Sarcoplasmic reticulum CuZnSOD NADPH oxidase H2O2 Phospholipase A2 ETC eNOS O2 − MnSOD H2O2 Mitochondrion Based on data from Sakellariou et al. Free Radic Res 48:12, 2014

What is the role of reactive species and oxidative stress after exercise?

The conventional approach F C I Rest Reactive species Exercise Cobley et al. Free Radic Biol Med 84:65, 2015

The conventional approach F C I Rest Responses and adaptations Reactive species Exercise Antioxidant supplementation Cobley et al. Free Radic Biol Med 84:65, 2015

A milestone F C I Gomez-Cabrera et al. J Physiol 567:113, 2005 12 25 20 9 15 NF-κB (au) 6 Endurance (%) 10 3 5 Untrained Trained Trained Allopurinol Trained Trained Vitamin C Gomez-Cabrera et al. J Physiol 567:113, 2005 Gomez-Cabrera et al. Am J Clin Nutr 87:142, 2008

Antioxidant supplementation either does not augment or hampers exercise adaptations “Too much of a good thing” * * Bartlett et al. Eur J Sport Sci 15:3, 2015

Non-antioxidant effects of antioxidants Redox active Redox inactive Vit E OH Vit E OH Vit E OH TAP TAP TAP PI3-kinase (inactive) PI3-kinase (inactive) PI3-kinase (active) Azzi et al. Arch Biochem Biophys 595:100, 2016

Redox individuality F C I Oxidative stress Reductive stress 0% 12% 100% Margaritelis et al. Redox Biol 2:520, 2014

Personalized antioxidant supplementation F C I Placebo Placebo High vitamin C (n=10) Vitamin C Vitamin C n = 100 Placebo Placebo Low vitamin C (n=10) Vitamin C Vitamin C 30 days 60 days Wash out 30 days Paschalis et al. Eur J Nutr 55:45, 2016

Beneficial effects of Vit C on the ‘rancid’ 100 80 High vitamin C group 60 Vitamin C (μmol/L) 40 Low vitamin C group 20 Pre supplementation Post supplementation 800 60 600 45 F2-isoprostanes (pg/mg cr.) 400 VO2max (ml/kg/min ) 30 200 15 Pre supplementation Post supplementation Pre supplementation Post supplementation Paschalis et al. Eur J Nutr 55:45, 2016

Stratification and regression to the mean 1st exercise trial Low EIOS F2-Isop change n=12 Moderate EIOS F2-Isop change n=12 High EIOS F2-Isop change n=12 2nd exercise trial Margaritelis et al. under review

Verification of regression to the mean F2-isoprostanes (% change) 1st trial 2nd trial 1st trial 2nd trial 1st trial 2nd trial High EIOS Moderate EIOS Low EIOS Margaritelis et al. under review

The role of oxidative stress in adaptations 1st exercise trial Low EIOS F2-Isop change n=12 Moderate EIOS F2-Isop change n=12 High EIOS F2-Isop change n=12 2nd exercise trial Redox & Performance Redox & Performance Cycling training 3 6 Time (weeks) Margaritelis et al. under review

Low oxidative stress leads to low adaptations F C I Low EIOS Low EIOS Moderate EIOS Moderate EIOS High EIOS High EIOS 5 10 15 20 10 20 30 VO2max (% change) Time trial (% change) a ‘free radical’ supplement Margaritelis et al. under review

Centrality of NADPH in redox regulation Veskoukis et al. under review

Nicotinamide riboside: an NADPH booster F C I Exercise Exercise Nicotinamide riboside 40 80 120 160 Time to exhaustion (s) Kourtzidis et al. under review

Conclusion F C I undamentality omplexity nvolvement

Acknowledgements Antonios Kyparos Aristidis Veskoukis Nikos Margaritelis Aristotle University of Thessaloniki, Greece Vassilis Paschalis University of Thessaly, Greece Anastasios Theodorou European University, Cyprus