title: Endurance exercise training induces fat depot-specific differences in basal autophagic activity.
abstract: The purpose of this study was to uncover the effect of exercise training on the expression of autophagy marker proteins in epididymal white adipose tissue (eWAT), inguinal WAT (iWAT), and the stromal vascular fraction (SVF) collected from eWAT. Male Wistar rats aged 4-5 weeks were randomly divided into two groups, sedentary control (n = 7) and exercise-trained (n = 7). Rats in the exercise-trained group were exercised on a treadmill set at a 5° incline 5 days/week for 9 weeks. We determined that the expression levels of an autophagosome-associating form of microtubule-associated protein 1 light chain 3 (LC3)-II and of p62 were significantly higher in eWAT from exercise-trained than from control rats, while those of adipose-specific deletion of autophagy-related protein (ATG7) and lysosomal-associated membrane protein type 2A (LAMP2a) showed no difference between groups. However, in iWAT, the expression levels of LC3-II and ATG7 were significantly higher in exercise-trained than in control rats. The expression of p62 was highly correlated with that of peroxisome proliferator-activated receptor γ (PPARγ), a master regulator of adipogenesis and lipid metabolism, in both WAT types (eWAT, r = 0.856, P < 0.05; iWAT, r = 0.762, P < 0.05), whereas LC3-II and PPARγ levels were highly correlated in eWAT (r = 0.765, P < 0.05) but not in iWAT (r = -0.306, ns). In SVF, the expression levels of LC3II, ATG7, and LAMP2a were significantly higher in exercise-trained than in control rats. These results suggest that exercise training suppresses basal autophagy activity in eWAT, but that this activity is enhanced in iWAT and SVF collected from eWAT. Thus, the adaptation of basal autophagic activity following exercise training exhibits fat depot-specific differences.
authors.affiliation: Graduate School of Health and Sports Science, Doshisha University, Kyoto 610-0321, Japan.
authors.forename: Goki
authors.initials: G
authors.lastname: Tanaka
authors.affiliation: Graduate School of Health and Sports Science, Doshisha University, Kyoto 610-0321, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kato
authors.affiliation: Graduate School of Health and Sports Science, Doshisha University, Kyoto 610-0321, Japan. Electronic address: tizawa@mail.doshisha.ac.jp.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Izawa
mesh_terms: D000222:Adaptation, Physiological; D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D052436:Adipose Tissue, White / Q000166:cytology* / Q000502:physiology*; D000818:Animals; D001343:Autophagy / Q000502:physiology*; D000071193:Autophagy-Related Protein 7; D015415:Biomarkers / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism; D052119:Lysosomal-Associated Membrane Protein 2 / Q000378:metabolism; D008297:Male; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D047495:PPAR gamma / Q000378:metabolism; D010805:Physical Conditioning, Animal / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D000071456:Sequestosome-1 Protein; D044764:Ubiquitin-Activating Enzymes / Q000378:metabolism
chemical_list: D000071193:Autophagy-Related Protein 7; D015415:Biomarkers; D006360:Heat-Shock Proteins; D052119:Lysosomal-Associated Membrane Protein 2; D008869:Microtubule-Associated Proteins; D047495:PPAR gamma; D000071456:Sequestosome-1 Protein; D044764:Ubiquitin-Activating Enzymes; C561242:Atg7 protein, rat; C526109:Anxa3 protein, rat; C491079:Sqstm1 protein, rat
keywords: Adipose tissue; Autophagy; Exercise training