Acute oxidative stress and systemic Nrf2 activation by the ketogenic diet.
The mechanisms underlying the efficacy of the ketogenic diet (KD) remain unknown. Recently, we showed that the KD increased glutathione (GSH) biosynthesis. Since the NF E2-related factor 2 (Nrf2) transcription factor is a primary responder to cellular stress and can upregulate GSH biosynthesis, we asked whether the KD activates the Nrf2 pathway. Here we report that rats consuming a KD show acute production of H(2)O(2) from hippocampal mitochondria, which decreases below control levels by 3 weeks, suggestive of an adaptive response. 4-Hydroxy-2-nonenal (4-HNE), an electrophilic lipid peroxidation end product known to activate the Nrf2 detoxification pathway, was also acutely increased by the KD. Nrf2 nuclear accumulation was evident in both the hippocampus and liver, and the Nrf2 target, NAD(P)H:quinone oxidoreductase (NQO1), exhibited increased activity in both the hippocampus and liver after 3 weeks. We also found chronic depletion of liver tissue GSH, while liver mitochondrial antioxidant capacity was preserved. These data suggest that the KD initially produces mild oxidative and electrophilic stress, which may systemically activate the Nrf2 pathway via redox signaling, leading to chronic cellular adaptation, induction of protective proteins, and improvement of the mitochondrial redox state.
Milder
Julie B
JB
Graduate Program in Neuroscience, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
Liang
Li-Ping
LP
Patel
Manisha
M
D021581:Active Transport, Cell Nucleus / Q000235:genetics; D000818:Animals; D055423:Diet, Ketogenic / Q000379:methods*; D006624:Hippocampus / Q000201:enzymology / Q000378:metabolism*; D015227:Lipid Peroxidation / Q000235:genetics; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology / Q000378:metabolism*; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000235:genetics / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D021381:Protein Transport / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D013312:Stress, Physiological / Q000235:genetics; D015533:Transcriptional Activation / Q000235:genetics*
D051267:NF-E2-Related Factor 2; C495637:Nfe2l2 protein, rat; D016660:NAD(P)H Dehydrogenase (Quinone); C507703:NQO1 protein, rat