Acute exercise and brain BACE1 protein content: a time course study.

Area of Science:

• Neuroscience
• Metabolic Health
• Exercise Physiology

Background:

• Obesity and insulin resistance are linked to neurodegenerative diseases.
• Previous studies indicate acute exercise may protect the brain in obese mice.
• The enzyme BACE1 (beta-secretase 1) is crucial for amyloid-beta production and its levels were previously found reduced post-exercise.

Purpose of the Study:

• To investigate the duration of exercise-induced changes in BACE1 levels.
• To examine the persistence of exercise effects in the prefrontal cortex and hippocampus following a single exercise bout in diet-induced obese mice.

Main Methods:

• Male C57BL/6J mice were fed a low-fat diet (LFD) or high-fat diet (HFD) for 7 weeks.
• HFD mice underwent a single bout of treadmill exercise and were then allowed 2, 8, or 24 hours of recovery.
• Levels of BACE1 and phosphorylated stress-related proteins (p38, JNK, AMPK, ERK) were measured in the prefrontal cortex and hippocampus.

Main Results:

• HFD significantly increased body mass and glucose intolerance compared to LFD.
• Prefrontal cortex BACE1 was reduced at 2 and 8 hours post-exercise, but not at 24 hours.
• Hippocampal BACE1 was reduced at 8 and 24 hours post-exercise.
• HFD increased neuronal stress markers (p38, JNK, AMPK) in the prefrontal cortex and JNK in the hippocampus, which were modulated by exercise.

Conclusions:

• A single bout of exercise effectively reduces BACE1 levels in the prefrontal cortex and hippocampus of obese mice.
• The reduction in prefrontal cortex BACE1 is transient, with levels returning to baseline by 24 hours post-exercise.
• Exercise also impacts neuronal stress pathways, suggesting a complex neuroprotective response that warrants further investigation into its temporal dynamics.