Endurance exercise training induces fat depot-specific differences in basal autophagic activity

Area of Science:

• Metabolism and Endocrinology
• Cellular Biology
• Exercise Physiology

Background:

• Autophagy is a crucial cellular process involved in maintaining homeostasis.
• Exercise training is known to influence metabolic processes in adipose tissue.
• Understanding the depot-specific effects of exercise on autophagy is important for metabolic health.

Purpose of the Study:

• To investigate the impact of exercise training on autophagy marker protein expression.
• To compare these effects across different white adipose tissue depots (epididymal and inguinal) and the stromal vascular fraction (SVF).

Main Methods:

• Male Wistar rats were divided into sedentary control and exercise-trained groups.
• Exercise training involved treadmill running at a 5° incline, 5 days/week for 9 weeks.
• Expression levels of autophagy markers (LC3-II, p62, ATG7, LAMP2a) and PPARγ were analyzed in eWAT, iWAT, and SVF.

Main Results:

• Exercise training increased LC3-II and p62 in eWAT, but not ATG7 or LAMP2a.
• In iWAT, LC3-II and ATG7 expression were significantly higher post-exercise.
• p62 expression correlated with PPARγ in both eWAT and iWAT; LC3-II and PPARγ correlated in eWAT.
• SVF showed increased LC3II, ATG7, and LAMP2a expression after exercise training.

Conclusions:

• Exercise training differentially regulates basal autophagy activity in a fat depot-specific manner.
• Autophagy is suppressed in eWAT but enhanced in iWAT and SVF following exercise.
• These findings highlight the complex adaptations of adipose tissue to exercise.