Exercise induces hippocampal BDNF through a PGC-1α/FNDC5 pathway.

Area of Science:

• Neuroscience
• Molecular Biology
• Exercise Physiology

Background:

• Exercise enhances cognitive function, with brain-derived neurotrophic factor (BDNF) implicated.
• The molecular mechanisms linking exercise to elevated BDNF are not fully understood.

Purpose of the Study:

• To investigate the role of FNDC5 (fibronectin type III domain-containing protein 5) and PGC-1α (peroxisome proliferator-activated receptor gamma coactivator 1-alpha) in exercise-induced BDNF expression.
• To elucidate the pathway connecting endurance exercise, FNDC5, and hippocampal BDNF levels.

Main Methods:

• Assessed FNDC5 levels in the hippocampus of mice after endurance exercise.
• Investigated the regulation of neuronal Fndc5 gene expression by PGC-1α using knockout mice (Pgc1a(-/-)).
• Examined the effect of FNDC5 manipulation (forced expression and knockdown) on Bdnf expression in primary cortical neurons.
• Administered FNDC5 peripherally to the liver via adenoviral vectors and measured hippocampal gene expression.

Main Results:

• Endurance exercise elevated FNDC5 expression in the mouse hippocampus.
• Neuronal Fndc5 expression is dependent on PGC-1α, with Pgc1a(-/-) mice exhibiting reduced Fndc5.
• Forced FNDC5 expression increased Bdnf levels, while FNDC5 knockdown decreased Bdnf.
• Peripheral FNDC5 delivery elevated blood irisin and induced Bdnf and other neuroprotective genes in the hippocampus.

Conclusions:

• Endurance exercise, PGC-1α, and FNDC5 are linked to BDNF expression in the brain.
• FNDC5 acts as a mediator connecting exercise-induced metabolic changes with neurotrophin signaling.
• This pathway represents a potential target for enhancing cognitive function and neuroprotection through exercise mimetics.