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Woraikat S, Chen D, Yang F, Tang C, He F, Qian K. Dexamethasone and Insulin Modulate Alanine Aminotransferase (ALT) Activity and Alanine Oxidation in C2C12 Cells in a Dose-Dependent Manner. Cureus 2024; 16:e59331. [PMID: 38817503 PMCID: PMC11137606 DOI: 10.7759/cureus.59331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2024] [Indexed: 06/01/2024] Open
Abstract
BACKGROUND The muscle cells myocytes are differentiated for the purpose of contraction function, which plays a major role in body metabolism and energy haemostasis, through different metabolic pathways, such as glucose and protein metabolic pathways. Alanine aminotransferase (ALT) plays a crucial role by reversibly catalysing transamination between alanine and a-ketoglutarate to form pyruvate and glutamate and by mediating the conversion of these four major intermediate metabolites. ALT plays important roles for energy homeostasis during fasting and prolonged exercise anaerobically, when muscle protein must first be broken down into its constituent amino acids. METHODS Mouse skeletal myoblast cell line C2C12 was cultured in Dulbecco's modified eagle medium (DMEM) growth medium, supplied with 2% horse serum supplemented with 1 uM insulin, 2 mM glutamine and penicillin and streptomycin antibiotics for seven days. The differentiation medium is refreshed every 24 hours. Then, C2C12 cells were treated with insulin and dexamethasone to examine their effects on myocytes' ALT activity. RESULTS In our study, we found an impact on ALT activity under different influences, including C2C12 differentiation, dexamethasone and insulin treatments, which shed light on the dynamic interplay between ALT activity, alanine metabolism, and cellular states, like differentiation and stress responses. CONCLUSION The study provides valuable insights into the dynamic regulation of ALT activity and alanine metabolism in C2C12 cells across differentiation and drug treatments. Further research is encouraged to explore the underlying mechanisms and their implications for muscle function, differentiation and potential therapeutic interventions in metabolic disorders.
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Affiliation(s)
- Saed Woraikat
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, CHN
| | - Defei Chen
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, CHN
| | - Fuyu Yang
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, TCD
| | - Chenglin Tang
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, CHN
| | - Fan He
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, CHN
| | - Kun Qian
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, CHN
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Vann CG, Haun CT, Osburn SC, Romero MA, Roberson PA, Mumford PW, Mobley CB, Holmes HM, Fox CD, Young KC, Roberts MD. Molecular Differences in Skeletal Muscle After 1 Week of Active vs. Passive Recovery From High-Volume Resistance Training. J Strength Cond Res 2021; 35:2102-2113. [PMID: 34138821 DOI: 10.1519/jsc.0000000000004071] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
ABSTRACT Vann, CG, Haun, CT, Osburn, SC, Romero, MA, Roberson, PA, Mumford, PW, Mobley, CB, Holmes, HM, Fox, CD, Young, KC, and Roberts, MD. Molecular differences in skeletal muscle after 1 week of active vs. passive recovery from high-volume resistance training. J Strength Cond Res 35(8): 2102-2113, 2021-Numerous studies have evaluated how deloading after resistance training (RT) affects strength and power outcomes. However, the molecular adaptations that occur after deload periods remain understudied. Trained, college-aged men (n = 30) performed 6 weeks of whole-body RT starting at 10 sets of 10 repetitions per exercise per week and finishing at 32 sets of 10 repetitions per exercise per week. After this period, subjects performed either active (AR; n = 16) or passive recovery (PR; n = 14) for 1 week where AR completed ∼15% of the week 6 training volume and PR ceased training. Variables related to body composition and recovery examined before RT (PRE), after 6 weeks of RT (POST), and after the 1-week recovery period (DL). Vastus lateralis (VL) muscle biopsies and blood samples were collected at each timepoint, and various biochemical and histological assays were performed. Group × time interactions (p < 0.05) existed for skeletal muscle myosin heavy chain (MHC)-IIa mRNA (AR > PR at POST and DL) and 20S proteasome activity (post-hoc tests revealed no significance in groups over time). Time effects (P < 0.05) existed for total mood disturbance and serum creatine kinase and mechano growth factor mRNA (POST > PRE &D L), VL pressure to pain threshold and MHC-IIx mRNA (PRE&DL > POST), Atrogin-1 and MuRF-1 mRNA (PRE < POST < DL), MHC-I mRNA (PRE < POST & DL), myostatin mRNA (PRE & POST < DL), and mechanistic target of rapamycin (PRE > POST & DL). No interactions or time effects were observed for barbell squat velocity, various hormones, histological metrics, polyubiquitinated proteins, or phosphorylated/pan protein levels of 4E-BP1, p70S6k, and AMPK. One week of AR after a high-volume training block instigates marginal molecular differences in skeletal muscle relative to PR. From a practical standpoint, however, both paradigms elicited largely similar responses.
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Affiliation(s)
| | - Cody T Haun
- Department of Exercise Science, LaGrange College, Lagrange, Georgia
| | | | - Matthew A Romero
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California
| | - Paul A Roberson
- Department of Cellular and Molecular Physiology, College of Medicine, The Pennsylvania State University, Hershey, Pennsylvania
| | - Petey W Mumford
- Department of Exercise Science, Lindenwood University, St. Charles, Missouri
| | - C Brooks Mobley
- Department of Physiology, University of Kentucky, Lexington, Kentucky; and
| | | | - Carlton D Fox
- School of Kinesiology, Auburn University, Auburn, Alabama
| | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, Alabama
| | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, Alabama
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Ramzan I, Taylor M, Phillips B, Wilkinson D, Smith K, Hession K, Idris I, Atherton P. A Novel Dietary Intervention Reduces Circulatory Branched-Chain Amino Acids by 50%: A Pilot Study of Relevance for Obesity and Diabetes. Nutrients 2020; 13:nu13010095. [PMID: 33396718 PMCID: PMC7824725 DOI: 10.3390/nu13010095] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 12/24/2020] [Accepted: 12/25/2020] [Indexed: 11/16/2022] Open
Abstract
Elevated circulating branched-chain amino acids (BCAAs; isoleucine, leucine, and valine) are associated with obesity and type 2 diabetes (T2D). Reducing circulatory BCAAs by dietary restriction was suggested to mitigate these risks in rodent models, but this is a challenging paradigm to deliver in humans. We aimed to design and assess the feasibility of a diet aimed at reducing circulating BCAA concentrations in humans, while maintaining energy balance and overall energy/protein intake. Twelve healthy individuals were assigned to either a 7-day BCAA-restricted diet or a 7-day control diet. Diets were iso-nitrogenous and iso-caloric, with only BCAA levels differing between the two. The BCAA-restricted diet significantly reduced circulating BCAA concentrations by ~50% i.e., baseline 437 ± 60 to 217 ± 40 µmol/L (p < 0.005). Individually, both valine (245 ± 33 to 105 ± 23 µmol/L; p < 0.0001), and leucine (130 ± 20 to 75 ± 13 µmol/L; p < 0.05), decreased significantly in response to the BCAA-restricted diet. The BCAA-restricted diet marginally lowered Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) levels: baseline 1.5 ± 0.2 to 1.0 ± 0.1; (p = 0.096). We successfully lowered circulating BCAAs by 50% while maintaining iso-nitrogenous, iso-caloric dietary intakes, and while meeting the recommended daily allowances (RDA) for protein requirements. The present pilot study represents a novel dietary means by which to reduce BCAA, and as such, provides a blueprint for a potential dietary therapeutic in obesity/diabetes.
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