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Objectives: Mitochondrial dysfunction in skeletal muscle has emerged as key to the development of obesity and its related metabolic disorders. Leucine (Leu) is an essential amino acid that has been reported to increase mitochondrial biogenesis in muscle cells, as has its metabolite β-hydroxy-β-methylbutyrate (HMB). However, two questions-which one is more potent and what is the cellular mechanisms of the action of Leu and HMB-remain to be answered. Therefore we aimed to investigate the effects of Leu and HMB on mitochondrial function in C2 C12 myotubes and analyze the underlying molecular mechanism.
Methods And Results: The effects of Leu and HMB on mitochondrial mass, mitochondrial respiration capacity, and the expression of genes related to mitochondrial biogenesis were evaluated in C2 C12 myotubes. Differentiated myotubes were treated with Leu (0.5 mM) or HMB (50 μM) with or without PPARβ/δ antagonist (GSK3787, 1 μM) and CDK4 antagonist (LY2835219, 1.5 μM), respectively, for 24 h. The results indicated that treatment with Leu or HMB significantly increased mitochondrial mass, mitochondrial respiration capacity, and the messenger RNA expression of genes associated with mitochondrial biogenesis (P < 0.05). In addition, these positive effects of Leu or HMB on these parameters were attenuated by GSK3787 and LY2835219 treatments (P < 0.05).
Conclusions: Our results provide evidence indicating that as with Leu, HMB alone could increase mitochondrial biogenesis and function via regulation of PPARβ/δ and CDK4 pathways. Moreover, HMB seems to be more potent than Leu in the positive regulation of mitochondrial biogenesis and function in C2 C12 myotubes because the dosage used for HMB was much lower than that for Leu.
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http://dx.doi.org/10.1016/j.nut.2018.09.032 | DOI Listing |
J Agric Food Chem
April 2025
School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, China.
3-Hydroxy-3-methylbutyrate (HMB), an important dietary supplement, can enhance the quality of life for sedentary and elderly people. However, the catalytic efficiency of the pathway enzymes limited the biosynthesis of HMB. Here, we identified an efficient 4-hydroxyphenylpyruvate dioxygenase (4-HPPD) from (HPPD) that converted l-Leucine (l-Leu) to HMB together with an efficient L-amino acid deaminase (L-AAD) in lab-preserved (L-AAD).
View Article and Find Full Text PDFNutrients
October 2021
Instituto de Investigación Sanitaria (IIS) Aragon, 50009 Zaragoza, Spain.
Low plasma levels of branched chain amino acids (BCAA) in liver cirrhosis are associated with hepatic encephalopathy (HE). We aimed to identify a metabolic signature of minimal hepatic encephalopathy (MHE) in malnourished cirrhotic patients and evaluate its modification with oral nutritional supplements (ONS) enriched with ß-Hydroxy-ß-methylbutyrate (HMB), a derivative of the BCAA leucine. Post hoc analysis was conducted on a double-blind placebo-controlled trial of 43 individuals with cirrhosis and malnutrition, who were randomized to receive, for 12 weeks, oral supplementation twice a day with either 220 mL of Ensure Plus Advance (HMB group, = 22) or with 220 mL of Ensure Plus High Protein (HP group, = 21).
View Article and Find Full Text PDFAm J Physiol Endocrinol Metab
March 2021
Center for Translational Research in Aging & Longevity, Department of Health & Kinesiology, Texas A&M University. College Station, Texas.
Branched-chain amino acids (BCAA) and their metabolites the branched-chain keto acids (BCKA) and β-hydroxy β-methylbutyric acid (HMB) are involved in the regulation of key signaling pathways in the anabolic response to a meal. However, their (inter)organ kinetics remain unclear. Therefore, branched-chain amino acids (BCAA) [leucine (Leu), valine (Val), isoleucine (Ile)], BCKA [α-ketoisocaproic acid (KIC), 3-methyl-2-oxovaleric acid (KMV), 2-oxoisovalerate (KIV)], and HMB across organ net fluxes were measured.
View Article and Find Full Text PDFJ Pers Med
March 2020
Department of Food Science and Nutrition, California Polytechnic State University, San Luis Obispo, CA 93407, USA.
While onset characteristics may vary, sarcopenia gradually develops over time as a result of the aging process, leading to muscle loss, disturbance of the muscle to fat ratio, and a variety of negative symptoms undermining the wellbeing, quality of life, and lifespan in the aging population globally. There is evidence that sarcopenia may be a cause and consequence of type 2 diabetes mellitus (T2DM) in the aging population. The importance of nutritional management in the prevention and/or deceleration of sarcopenia is critical, with the main focus placed on the amount and quality of protein intake.
View Article and Find Full Text PDFJ Appl Physiol (1985)
February 2020
US Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas.
Leucine (Leu) and its metabolite β-hydroxy-β-methylbutyrate (HMB) stimulate mechanistic target of rapamycin (mTOR) complex 1 (mTORC1)-dependent protein synthesis in the skeletal muscle of neonatal pigs. This study aimed to determine whether HMB and Leu utilize common nutrient-sensing mechanisms to activate mTORC1. In , neonatal pigs were fed one of five diets for 24 h: low protein (LP), high protein (HP), or LP supplemented with 4 (LP+HMB4), 40 (LP+HMB40), or 80 (LP+HMB80) μmol HMB·kg body wt·day.
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