Open AccessPI 3K‐ AKT ‐ FOXO 1 pathway targeted by skeletal muscle micro RNA to suppress proteolytic gene expression in response to carbohydrate intake during aerobic exercise
Author(s) -
Margolis Lee M.,
Berryman Claire E.,
Murphy Nancy E.,
Carrigan Christopher T.,
Young Andrew J.,
Carbone John W.,
Pasiakos Stefan M.
Publication year - 2018
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.13931
Subject(s) - skeletal muscle , microrna , chemistry , protein kinase b , pi3k/akt/mtor pathway , medicine , endocrinology , biochemistry , signal transduction , gene
Ingesting protein and carbohydrate together during aerobic exercise suppresses the expression of specific skeletal muscle micro RNA and promotes muscle hypertrophy. Determining whether there are independent effects of carbohydrate and protein on micro RNA will allow for a clearer understanding of the mechanistic role micro RNA serve in regulating skeletal muscle protein synthetic and proteolytic responses to nutrition and exercise. This study determined skeletal muscle micro RNA responses to aerobic exercise with or without carbohydrate, and recovery whey protein ( WP ). Seventeen males were randomized to consume carbohydrate ( CHO ; 145 g; n = 9) or non‐nutritive control ( CON ; n = 8) beverages during exercise. Muscle was collected before ( BASE ) and after 80 min of steady‐state exercise (1.7 ± 0.3 V̇O 2 L·min −1 ) followed by a 2‐mile time trial (17.9 ± 3.5 min; POST ), and 3‐h into recovery after consuming WP (25 g; REC ). RT ‐ qPCR was used to determine micro RNA and mRNA expression. Bioinformatics analysis was conducted using the mirPath software. Western blotting was used to assess protein signaling. The expression of six micro RNA (miR‐19b‐3p, miR‐99a‐5p, miR‐100‐5p, miR‐222‐3p, miR‐324‐3p, and miR‐486‐5p) were higher ( P < 0.05) in CHO compared to CON , all of which target the PI 3K‐ AKT , ubiquitin proteasome, FOXO , and mTORC 1 pathways. p‐ AKT T hr473 and p‐ FOXO 1 Thr24 were higher ( P < 0.05) in POST CHO compared to CON . The expression of PTEN was lower ( P < 0.05) in REC CHO than CON , while MURF 1 was lower ( P < 0.05) POST CHO than CON . These findings suggest the mechanism by which micro RNA facilitate skeletal muscle adaptations in response to exercise with carbohydrate and protein feeding is by inhibiting markers of proteolysis.