TY - JOUR
T1 - Postexercise changes in myocellular lipid droplet characteristics of young lean individuals are affected by circulatory nonesterified fatty acids
AU - Daemen, S.
AU - van Polanen, N.
AU - Bilet, L.
AU - Phielix, E.
AU - Moonen-Kornips, E.
AU - Schrauwen-Hinderling, V.B.
AU - Schrauwen, P.
AU - Hesselink, M.K.C.
N1 - Funding Information:
This work was funded by Diabetes Fonds (Dutch Diabetes Research Foundation) (Grant DF 2014.00.1756; to S.D.), European Research Council (ERC) (759161 “MRS in diabetes”; to V.B. and S.H.), Hartstichting (Heart Foundation) (CVON2014-02 ENERGISE; to N.v.P.).
Funding Information:
This work was funded by Diabetes Fonds (Dutch Diabetes Research Foundation) (Grant DF 2014.00.1756; to S.D.), European Research Council (ERC) (759161 “MRS in diabetes”; to V.B. and S.-H.), Hartstichting (Heart Foundation) (CVON2014-02 ENERGISE; to N.v.P.).
Publisher Copyright:
Copyright © 2021 the American Physiological Society.
PY - 2021/10/1
Y1 - 2021/10/1
N2 - Intramyocellular lipid (IMCL) content is an energy source during acute exercise. Nonesterified fatty acid (NEFA) levels can compete with IMCL utilization during exercise. IMCL content is stored as lipid droplets (LDs) that vary in size, number, subcellular distribution, and in coating with LD protein PLIN5. Little is known about how these factors are affected during exercise and recovery. Here, we aimed to investigate the effects of acute exercise with and without elevated NEFA levels on intramyocellular LD size and number, intracellular distribution and PLIN5 coating, using high-resolution confocal microscopy. In a crossover study, 9 healthy lean young men performed a 2-h moderate intensity cycling protocol in the fasted (high NEFA levels) and glucose-fed state (low NEFA levels). IMCL and LD parameters were measured at baseline, directly after exercise and 4 h postexercise. We found that total IMCL content was not changed directly after exercise (irrespectively of condition), but IMCL increased 4 h postexercise in the fasting condition, which was due to an increased number of LDs rather than changes in size. The effects were predominantly detected in type I muscle fibers and in LDs coated with PLIN5. Interestingly, subsarcolemmal, but not intermyofibrillar IMCL content, was decreased directly after exercise in the fasting condition and was replenished during the 4 h recovery period. In conclusion, acute exercise affects IMCL storage during exercise and recovery, particularly in type I muscle fibers, in the subsarcolemmal region and in the presence of PLIN5. Moreover, the effects of exercise on IMCL content are affected by plasma NEFA levels.NEW & NOTEWORTHY Skeletal muscle stores lipids in lipid droplets (LDs) that can vary in size, number, and location and are a source of energy during exercise. Specifically, subsarcolemmal LDs were used during exercise when fasted. Exercising in the fasted state leads to postrecovery elevation in IMCL levels due to an increase in LD number in type I muscle fibers, in subsarcolemmal region and decorated with PLIN5. These effects are blunted by glucose ingestion during exercise and recovery.
AB - Intramyocellular lipid (IMCL) content is an energy source during acute exercise. Nonesterified fatty acid (NEFA) levels can compete with IMCL utilization during exercise. IMCL content is stored as lipid droplets (LDs) that vary in size, number, subcellular distribution, and in coating with LD protein PLIN5. Little is known about how these factors are affected during exercise and recovery. Here, we aimed to investigate the effects of acute exercise with and without elevated NEFA levels on intramyocellular LD size and number, intracellular distribution and PLIN5 coating, using high-resolution confocal microscopy. In a crossover study, 9 healthy lean young men performed a 2-h moderate intensity cycling protocol in the fasted (high NEFA levels) and glucose-fed state (low NEFA levels). IMCL and LD parameters were measured at baseline, directly after exercise and 4 h postexercise. We found that total IMCL content was not changed directly after exercise (irrespectively of condition), but IMCL increased 4 h postexercise in the fasting condition, which was due to an increased number of LDs rather than changes in size. The effects were predominantly detected in type I muscle fibers and in LDs coated with PLIN5. Interestingly, subsarcolemmal, but not intermyofibrillar IMCL content, was decreased directly after exercise in the fasting condition and was replenished during the 4 h recovery period. In conclusion, acute exercise affects IMCL storage during exercise and recovery, particularly in type I muscle fibers, in the subsarcolemmal region and in the presence of PLIN5. Moreover, the effects of exercise on IMCL content are affected by plasma NEFA levels.NEW & NOTEWORTHY Skeletal muscle stores lipids in lipid droplets (LDs) that can vary in size, number, and location and are a source of energy during exercise. Specifically, subsarcolemmal LDs were used during exercise when fasted. Exercising in the fasted state leads to postrecovery elevation in IMCL levels due to an increase in LD number in type I muscle fibers, in subsarcolemmal region and decorated with PLIN5. These effects are blunted by glucose ingestion during exercise and recovery.
KW - exercise
KW - lipid droplets
KW - muscle
KW - ENDURANCE-TRAINED MALES
KW - SKELETAL-MUSCLE
KW - INSULIN-RESISTANCE
KW - CARBOHYDRATE-METABOLISM
KW - INTENSITY EXERCISE
KW - PERILIPIN PROTEINS
KW - GENE-EXPRESSION
KW - OXIDATION
KW - LIPOTOXICITY
KW - MITOCHONDRIA
U2 - 10.1152/ajpendo.00654.2020
DO - 10.1152/ajpendo.00654.2020
M3 - Article
C2 - 34396784
SN - 0193-1849
VL - 321
SP - E453-E463
JO - American Journal of Physiology : Endocrinology and Metabolism
JF - American Journal of Physiology : Endocrinology and Metabolism
IS - 4
ER -