Time-Dependent Changes in Increased Levels of Plasma Irisin and Muscle PGC-1α and FNDC5 after Exercise in Mice

Time-Dependent Changes in Increased Levels of Plasma Irisin and Muscle PGC-1α and FNDC5 after Exercise in Mice

MINHUI PANG,¹ JIANWEI YANG,¹ JIAMING RAO,¹ HAIQING WANG,¹ JIAYI ZHANG,¹ SHENGYONG WANG,¹ XIONGFEI CHEN² and XIAOMEI DONG¹

¹Department of Epidemiology and Health Statistics, Basic Medical College of Jinan University, Guangzhou, China
²Guangzhou Center for Disease Control and Prevention, Guangzhou, Guangdong, China

Exercise induces the expression of peroxisome proliferator-activated receptor gamma co-activator 1-α (PGC-1α) in skeletal muscle, which promotes the cleavage of fibronectin type III domain-containing protein 5 (FNDC5) to irisin. To explore the relationship between irisin and its regulators, we analyzed the plasma irisin levels and the muscle levels of FNDC5 and PGC-1α after exercise. Male C57BL/6J mice underwent a treadmill exercise (60% of VO_2max) for 30 min or one hour (h), and blood and gastrocnemius samples were collected before exercise (pre-exercise), immediately after exercise, and during 24-h recovery after 1-h exercise. We found that plasma irisin levels were significantly increased during exercise (P < 0.05), while FNDC5 protein levels were not significantly increased. Moreover, PGC-1α mRNA and protein levels were significantly increased during 30-min exercise, but were decreased during 1-h exercise. After 1-h exercise, the irisin levels peaked at 6 h (20.71 ± 0.25 ng/ml) and decreased to pre-exercise levels by 24 h (15.45 ± 0.27 ng/ml). Likewise, PGC-1α mRNA and protein levels were increased at 1 h and maintained at elevated levels for 6 h; thereafter, the expression levels of PGC1-α protein were decreased to pre-exercise levels at 12 h. Thus, the restoration of PGC-1α expression to the pre-exercise levels was followed by the decrease in plasma irisin levels. By contrast, during 24-h recovery, the expression levels of FNDC5 mRNA and protein were maintained at elevated levels. These results suggest that the coordinated expression of FNDC5 and PGC-1α may contribute to the increased levels of plasma irisin after exercise.

keywords —— acute exercise intervention, FNDC5, irisin, PGC-1α, time points

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Tohoku J. Exp. Med., 2018, 244, 93-103

Correspondence: Xiongfei Chen, M.D., Guangzhou Center for Disease Control and Prevention, No.1 Qide Road of Baiyun District of Guangzhou, Guangdong 510440, China.

e-mail: 11742513@qq.com

Xiaomei Dong, Ph.D., Department of Epidemiology and Health Statistics, Basic Medical College of Jinan University, No.601 Huangpu Road West of Tianhe District of Guangzhou, Guangdong 510632, China.

e-mail: ntydxm@126.com