Identification of human exercise-induced myokines using secretome analysis

Area of Science:

• Exercise physiology
• Molecular biology
• Endocrinology

Background:

• Endurance exercise improves cardio-metabolic health.
• Myokines, muscle-derived cytokines, are implicated but poorly understood in acute exercise.
• Limited data exists on human myokine responses to acute endurance exercise.

Purpose of the Study:

• Identify novel exercise-induced myokines in humans.
• Investigate myokine changes following acute and training-based endurance exercise.
• Determine if identified myokines are present in circulation.

Main Methods:

• One-legged acute endurance exercise (1 hour) in 12 males.
• 12-week exercise training intervention in 18 males.
• Microarray analysis of muscle secretome, followed by ELISA/multiplex assays for plasma validation.

Main Results:

• Acute exercise revealed 86 putative myokines, with CX3CL1 (fractalkine) and CCL2 (MCP-1) increasing at mRNA and plasma levels.
• Known myokines IL-6 and FGF 21 changed at mRNA but not plasma levels post-acute exercise.
• Exercise training identified 69 putative myokines, with limited overlap (13 genes) compared to acute exercise.

Conclusions:

• CX3CL1 and CCL2 are identified as myokines induced by acute exercise at both gene and protein levels.
• These novel myokines may mediate communication between skeletal muscle and other organs.
• Acute exercise responses differ significantly from chronic training adaptations in myokine profiles.