NAD(+)/NADH and skeletal muscle mitochondrial adaptations to exercise

Area of Science:

• Exercise physiology
• Mitochondrial biology
• Cellular metabolism

Background:

• Pyridine nucleotides, NAD(+) and NADH, are crucial coenzymes for mitochondrial ATP generation.
• Exercise disrupts NAD(+) and NADH levels in skeletal muscle, affecting the NAD(+)/NADH ratio and cellular redox state.
• Emerging research highlights signaling pathways sensitive to NAD(+)(H) fluctuations and the role of metabolic compartmentation.

Purpose of the Study:

• To review the known and unknown contributions of NAD(+)(H) metabolism to mitochondrial adaptations.
• To examine the roles of NAD(+)(H)-sensitive signaling proteins (SIRTs, PARPs, CtBP) in exercise responses.
• To connect cellular redox state changes to immediate metabolic and transcriptional adaptations induced by exercise.

Main Methods:

• Literature review focusing on NAD(+)(H) metabolism and exercise.
• Analysis of signaling pathways involving sirtuins (SIRT1, SIRT3), PARPs (PARP1, PARP2), and CtBP.
• Integration of findings on acute and chronic endurance exercise effects.

Main Results:

• Exercise significantly perturbs NAD(+)(H) levels and the NAD(+)/NADH ratio in skeletal muscle.
• NAD(+)(H) metabolism influences key signaling proteins involved in cellular adaptation.
• Compartmentation of NAD(+)(H) plays a critical role in mediating exercise-induced signaling.

Conclusions:

• NAD(+)(H) metabolism and associated proteins are integral to mitochondrial adaptations to exercise.
• Understanding these pathways is key to elucidating the link between redox state and exercise responses.
• Further research is needed to fully elucidate the complex roles of NAD(+)(H) in exercise physiology.