miRNA-206 in muscle and central nervous system crosstalk during exercise: A double-edged sword with therapeutic potential.

Physical activity triggers complex molecular responses in skeletal muscle, with increasing evidence showing systemic signaling roles for muscle-derived microRNAs (myomiRs). Among these, miR-206 has attracted attention for its dual function: promoting muscle regeneration but potentially harming the central nervous system (CNS). This review examines how miR-206 expression is regulated during exercise and its effects on muscle biology-such as fiber-type specification, mitochondrial changes, and neuromuscular junction (NMJ) repair. It also explores the paradoxical effects of high miR-206 levels in the CNS, where it targets brain-derived neurotrophic factor (BDNF), reducing neuroplasticity and increasing vulnerability to neuropsychiatric and neurodegenerative diseases. The review highlights disease-specific aspects, showing miR-206 as harmful in Alzheimer's, stroke, and depression, but potentially protective in amyotrophic lateral sclerosis (ALS). We discuss its potential as a biomarker and therapeutic target, stressing tissue-specific regulation approaches. Overall, miR-206 plays a key role in muscle-brain communication, with important implications for exercise, aging, and CNS disorders.