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Reed CH, Tystahl AC, Eo H, Buhr TJ, Bauer EE, Lee JH, Clark PJ, Valentine RJ. The Influence of Stress and Binge-Patterned Alcohol Drinking on Mouse Skeletal Muscle Protein Synthesis and Degradation Pathways. Biomolecules 2024; 14:527. [PMID: 38785934 PMCID: PMC11118922 DOI: 10.3390/biom14050527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/30/2024] [Accepted: 04/09/2024] [Indexed: 05/25/2024] Open
Abstract
Adverse experiences (e.g., acute stress) and alcohol misuse can both impair skeletal muscle homeostasis, resulting in reduced protein synthesis and greater protein breakdown. Exposure to acute stress is a significant risk factor for engaging in alcohol misuse. However, little is known about how these factors together might further affect skeletal muscle health. To that end, this study investigated the effects of acute stress exposure followed by a period of binge-patterned alcohol drinking on signaling factors along mouse skeletal muscle protein synthesis (MPS) and degradation (MPD) pathways. Young adult male C57BL/6J mice participated in the Drinking in the Dark paradigm, where they received 2-4 h of access to 20% ethanol (alcohol group) or water (control group) for four days to establish baseline drinking levels. Three days later, half of the mice in each group were either exposed to a single episode of uncontrollable tail shocks (acute stress) or remained undisturbed in their home cages (no stress). Three days after stress exposure, mice received 4 h of access to 20% ethanol (alcohol) to model binge-patterned alcohol drinking or water for ten consecutive days. Immediately following the final episode of alcohol access, mouse gastrocnemius muscle was extracted to measure changes in relative protein levels along the Akt-mTOR MPS, as well as the ubiquitin-proteasome pathway (UPP) and autophagy MPD pathways via Western blotting. A single exposure to acute stress impaired Akt singling and reduced rates of MPS, independent of alcohol access. This observation was concurrent with a potent increase in heat shock protein seventy expression in the muscle of stressed mice. Alcohol drinking did not exacerbate stress-induced alterations in the MPS and MPD signaling pathways. Instead, changes in the MPS and MPD signaling factors due to alcohol access were primarily observed in non-stressed mice. Taken together, these data suggest that exposure to a stressor of sufficient intensity may cause prolonged disruptions to signaling factors that impact skeletal muscle health and function beyond what could be further induced by periods of alcohol misuse.
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Affiliation(s)
- Carter H Reed
- Department of Biology, Grand View University, Des Moines, IA 50316, USA;
| | - Anna C. Tystahl
- Department of Kinesiology, Iowa State University, Ames, IA 50011, USA; (A.C.T.)
| | - Hyeyoon Eo
- Department of Kinesiology, Iowa State University, Ames, IA 50011, USA; (A.C.T.)
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
| | - Trevor J. Buhr
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
| | - Ella E. Bauer
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
| | - Ji Heun Lee
- Department of Kinesiology, Iowa State University, Ames, IA 50011, USA; (A.C.T.)
| | - Peter J. Clark
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
| | - Rudy J. Valentine
- Department of Physical Therapy and Kinesiology, University of Massachusetts Lowell, Lowell, MA 01854, USA
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Bazzi SA, Maguire C, Mayfield RD, Melamed E. Alcohol induces concentration-dependent transcriptomic changes in oligodendrocytes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.22.559075. [PMID: 37790537 PMCID: PMC10542481 DOI: 10.1101/2023.09.22.559075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Oligodendrocytes are a key cell type within the central nervous system (CNS) that generate the myelin sheath covering axons, enabling fast propagation of neuronal signals. Alcohol consumption is known to affect oligodendrocytes and white matter in the CNS. However, most studies have focused on fetal alcohol spectrum disorder and severe alcohol use disorder. Additionally, the impact of alcohol dosage on oligodendrocytes has not been previously investigated. In this study, we evaluated transcriptomic changes in C57BL6/J cultured mature oligodendrocytes following exposure to moderate and high concentrations of alcohol. We found that high concentrations of alcohol elicited gene expression changes across a wide range of biological pathways, including myelination, protein translation, integrin signaling, cell cycle regulation, and inflammation. Further, our results demonstrate that transcriptomic changes are indeed dependent on alcohol concentration, with moderate and high concentrations of alcohol provoking distinct gene expression profiles. In conclusion, our study demonstrates that alcohol-induced transcriptomic changes in oligodendrocytes are concentration-dependent and may have critical downstream impacts on myelin production. Targeting alcohol-induced changes in cell cycle regulation, integrin signaling, inflammation, or protein translation regulation may uncover mechanisms for modulating myelin production or inhibition. Furthermore, gaining a deeper understanding of alcohol's effects on oligodendrocyte demyelination and remyelination could help uncover therapeutic pathways that can be utilized independent of alcohol to aid in remyelinating drug design.
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Affiliation(s)
- Sam A Bazzi
- Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
| | - Cole Maguire
- Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
| | - R Dayne Mayfield
- Department of Neuroscience, The University of Texas at Austin, Austin, TX, USA
| | - Esther Melamed
- Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
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3
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Moser SE, Brown AM, Ganjayi MS, Otis JS, Baumann CW. Excessive Ethanol Intake in Mice Does Not Impair Recovery of Torque after Repeated Bouts of Eccentric Contractions. Med Sci Sports Exerc 2023; 55:873-883. [PMID: 36728527 DOI: 10.1249/mss.0000000000003118] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE Alcoholics develop muscle atrophy and weakness from excessive ethanol (EtOH) intake. To date, most research has examined outcomes of alcohol-induced atrophy and weakness under basal or unstressed conditions despite physical stress being a normal occurrence in a physiological setting. Therefore, this study set out to determine if recovery of torque is impaired after repetitive bouts of physical stress in skeletal muscle during excessive short-term (experiment 1) and long-term (experiment 2) EtOH consumption. METHODS Twenty male and female mice were assigned to receive either 20% EtOH in their drinking water or 100% water. Short- and long-term consumption was predetermined to be EtOH intake starting at 4 and 26 wk, respectively. Anterior crural muscles performed repeated bouts of physical stress using in vivo eccentric contractions, with tetanic isometric torque being measured immediately pre- and postinjury. A total of 10 bouts were completed with 14 d between each bout within bouts 1-5 (experiment 1) and bouts 6-10 (experiment 2), and 12 wk between bouts 5 and 6. RESULTS Mice consuming EtOH had blood alcohol concentrations up to 270 mg·dL -1 . In experiment 1, five bouts of eccentric contractions did not reduce recovery of torque, regardless of sex or EtOH treatment ( P ≥ 0.173). Similarly, in experiment 2, preinjury torques did not differ from day 14 values regardless of sex or treatment ( P ≥ 0.322). However, there was a group effect in female mice for bouts 6 and 10 during experiment 2, with female EtOH mice being weaker than controls ( P ≤ 0.002). CONCLUSIONS Excessive short- or long-term EtOH misuse in a mouse model did not affect the muscle's ability to regain strength after repeated bouts of eccentric contractions, suggesting that EtOH may not be as detrimental to recovery as once predicted.
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Affiliation(s)
| | | | | | - Jeffrey S Otis
- Department of Kinesiology and Health, Georgia State University, GA
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Li W, Yu T. Relationship between 25-hydroxyvitamin D and IGF1: a cross-sectional study of the Third National Health and Nutrition Examination Survey participants. JOURNAL OF HEALTH, POPULATION, AND NUTRITION 2023; 42:35. [PMID: 37072869 PMCID: PMC10111687 DOI: 10.1186/s41043-023-00374-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 04/07/2023] [Indexed: 04/20/2023]
Abstract
BACKGROUND 25-Hydroxyvitamin D (25OHD) and insulin-like growth factor 1 (IGF1) are crucial for bone health. Some studies have shown that they interact, whereas others have indicated no association. However, it remains inconclusive whether the interaction between the two is dose dependent. Herein, we explored the relationship between 25OHD and IGF1 by conducting a cross-sectional study. METHODS This study involved 6,046 individuals from the Third National Health and Nutrition Examination Survey (NHANES III). The dependent and independent variables were IGF1 and 25OHD levels, respectively. The covariates included age, sex, race, BMI, exercise, smoking behavior, alcohol intake, diabetes, and serum calcium level. Multiple linear regression and generalized additive model were employed to analyze the relationship between 25OHD and IGF1. Interaction and hierarchical analyses were also performed. RESULTS The 25OHD and IGF1 levels positively correlated after adjusting for covariates (β = 0.16, 95% CI: 0.04-0.29, P = 0.0103). Smooth curve fitting demonstrated a curvilinear relationship. When the 25OHD level was < 75 nmol/L, a positive correlation (β = 0.43, 95% CI: 0.25-0.62, P < 0.0001) was observed. When the 25OHD level was > 75 nmol/L, a negative correlation was observed (β = -0.53, 95% CI: -0.90 to -0.15, P = 0.0057). CONCLUSION This study demonstrated a nonlinear relationship between 25OHD and IGF1. It suggests that keeping the 25OHD level within a specific range may be more conducive to bone health. Additionally, when IGF1 is used to evaluate the efficacy and safety of recombinant human growth hormone (rhGH) in growth hormone deficiency treatment, the effect of 25OHD on the actual IGF1 level should be taken into account.
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Affiliation(s)
- Wei Li
- Department of Child Health Care, West China Second University Hospital, Sichuan University, No. 20, Section 3, Renmin South Road, Wuhou District, Chengdu, 610044, Sichuan, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, No. 20, Section 3, Renmin South Road, Wuhou District, Chengdu, 610044, Sichuan, China
| | - Tao Yu
- Department of Child Health Care, West China Second University Hospital, Sichuan University, No. 20, Section 3, Renmin South Road, Wuhou District, Chengdu, 610044, Sichuan, China.
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, No. 20, Section 3, Renmin South Road, Wuhou District, Chengdu, 610044, Sichuan, China.
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Ho AMC, Peyton MP, Scaletty SJ, Trapp S, Schreiber A, Madden BJ, Choi DS, Matthews DB. Chronic Intermittent Ethanol Exposure Alters Behavioral Flexibility in Aged Rats Compared to Adult Rats and Modifies Protein and Protein Pathways Related to Alzheimer's Disease. ACS OMEGA 2022; 7:46260-46276. [PMID: 36570296 PMCID: PMC9774340 DOI: 10.1021/acsomega.2c04528] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 11/17/2022] [Indexed: 05/13/2023]
Abstract
Repeated excessive alcohol consumption increases the risk of developing cognitive decline and dementia. Hazardous drinking among older adults further increases such vulnerabilities. To investigate whether alcohol induces cognitive deficits in older adults, we performed a chronic intermittent ethanol exposure paradigm (ethanol or water gavage every other day 10 times) in 8-week-old young adult and 70-week-old aged rats. While spatial memory retrieval ascertained by probe trials in the Morris water maze was not significantly different between ethanol-treated and water-treated rats in both age groups after the fifth and tenth gavages, behavioral flexibility was impaired in ethanol-treated rats compared to water-treated rats in the aged group but not in the young adult group. We then examined ethanol-treatment-associated hippocampal proteomic and phosphoproteomic differences distinct in the aged rats. We identified several ethanol-treatment-related proteins, including the upregulations of the Prkcd protein level, several of its phosphosites, and its kinase activity and downregulation in the Camk2a protein level. Our bioinformatic analysis revealed notable changes in pathways involved in neurotransmission regulation, synaptic plasticity, neuronal apoptosis, and insulin receptor signaling. In conclusion, our behavioral and proteomic results identified several candidate proteins and pathways potentially associated with alcohol-induced cognitive decline in aged adults.
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Affiliation(s)
- Ada Man-Choi Ho
- Department
of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota55905, United States
| | - Mina P. Peyton
- Bioinformatics
and Computational Biology Program, University
of Minnesota, Minneapolis, Minnesota55455, United States
| | - Samantha J. Scaletty
- Department
of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota55905, United States
| | - Sarah Trapp
- Department
of Psychology, University of Wisconsin—Eau
Claire, Eau Claire, Wisconsin54701, United States
| | - Areonna Schreiber
- Department
of Psychology, University of Wisconsin—Eau
Claire, Eau Claire, Wisconsin54701, United States
| | - Benjamin J. Madden
- Mayo
Clinic Proteomics Core, Mayo Clinic, Rochester, Minnesota55905, United States
| | - Doo-Sup Choi
- Department
of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota55905, United States
- Department
of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota55905, United States
| | - Douglas B. Matthews
- Department
of Psychology, University of Wisconsin—Eau
Claire, Eau Claire, Wisconsin54701, United States
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Reed CH, Buhr TJ, Tystahl AC, Bauer EE, Clark PJ, Valentine RJ. The effects of voluntary binge-patterned ethanol ingestion and daily wheel running on signaling of muscle protein synthesis and degradation in female mice. Alcohol 2022; 104:45-52. [PMID: 35926812 DOI: 10.1016/j.alcohol.2022.06.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 06/17/2022] [Accepted: 06/22/2022] [Indexed: 01/26/2023]
Abstract
Excessive ethanol ingestion can reduce skeletal muscle protein synthesis (MPS) through the disruption of signaling along the Akt-mTOR pathway and increase muscle protein degradation (MPD) through the Ubiquitin Proteasome Pathway (UPP) and autophagy. Identification of interventions that curb the disrupting effects of alcohol misuse on MPS and MPD are of central importance for the prevention of chronic health complications that arise from muscle loss. Physical activity is one potential strategy to combat the deleterious effects of alcohol on skeletal muscle. Therefore, the purpose of this study was to investigate the interaction between daily wheel running and binge-patterned ethanol consumption, through episodes of voluntary binge-patterned ethanol drinking, on signaling factors along the Akt-mTOR, Ubiquitin-Proteasome, and autophagy pathways. Adult female C57BL/6J mice received daily access to cages with or without running wheels for 2.5 h/day for five weeks. During the final five days of the study, mice received 2-4 h of daily access to sipper tubes containing water (n = 14 sedentary; n = 15 running) or 20% ethanol (n = 14 sedentary; n = 16 running) 30 min after running wheel access, using the "Drinking in the Dark" (DID) model of binge-patterned ethanol consumption. Immediately after the final episode of DID, gastrocnemius muscle was extracted. Western blotting was performed to measure proteins along Akt-mTOR, Ubiquitin-Proteasome, and autophagy pathways, and PCR was used to assess mRNA expression of atrogenes. Ethanol access increased expression of MAFbx by 82% (p = 0.048), but did not robustly influence Akt-mTOR or UPP signaling. Daily wheel access did not prevent alcohol-induced MAFbx expression; however, ethanol access decreased the phosphorylation of p70S6K by 45% in running mice (p = 0.020). These results suggest that physical activity may be insufficient to prevent alcohol-induced changes to signaling factors along pathways involved in muscle loss. Instead, binge-patterned ethanol ingestion may impair the benefits of physical activity on factors involved in MPS.
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Affiliation(s)
- Carter H Reed
- Department of Kinesiology, Forker Building, 534 Wallace Road, Iowa State University, Ames, IA, 50011, United States; Interdepartmental Graduate Program of Nutritional Sciences, MacKay Hall, 2302 Osborn Drive, Iowa State University, Ames, IA, 50011, United States
| | - Trevor J Buhr
- Neuroscience Program, MacKay Hall, 2302 Osborn Drive, Iowa State University, Ames, IA, 50011, United States; Department of Food Science and Human Nutrition, MacKay Hall, 2302 Osborn Drive, Iowa State University, Ames, IA, 50011, United States
| | - Anna C Tystahl
- Department of Kinesiology, Forker Building, 534 Wallace Road, Iowa State University, Ames, IA, 50011, United States
| | - Ella E Bauer
- Interdepartmental Graduate Program of Nutritional Sciences, MacKay Hall, 2302 Osborn Drive, Iowa State University, Ames, IA, 50011, United States; Neuroscience Program, MacKay Hall, 2302 Osborn Drive, Iowa State University, Ames, IA, 50011, United States; Department of Food Science and Human Nutrition, MacKay Hall, 2302 Osborn Drive, Iowa State University, Ames, IA, 50011, United States
| | - Peter J Clark
- Interdepartmental Graduate Program of Nutritional Sciences, MacKay Hall, 2302 Osborn Drive, Iowa State University, Ames, IA, 50011, United States; Neuroscience Program, MacKay Hall, 2302 Osborn Drive, Iowa State University, Ames, IA, 50011, United States; Department of Food Science and Human Nutrition, MacKay Hall, 2302 Osborn Drive, Iowa State University, Ames, IA, 50011, United States.
| | - Rudy J Valentine
- Department of Kinesiology, Forker Building, 534 Wallace Road, Iowa State University, Ames, IA, 50011, United States; Interdepartmental Graduate Program of Nutritional Sciences, MacKay Hall, 2302 Osborn Drive, Iowa State University, Ames, IA, 50011, United States; Neuroscience Program, MacKay Hall, 2302 Osborn Drive, Iowa State University, Ames, IA, 50011, United States.
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7
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Moser SE, Brown AM, Clark BC, Arnold WD, Baumann CW. Neuromuscular mechanisms of weakness in a mouse model of chronic alcoholic myopathy. Alcohol Clin Exp Res 2022; 46:1636-1647. [PMID: 35869821 PMCID: PMC9804636 DOI: 10.1111/acer.14907] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/13/2022] [Accepted: 07/14/2022] [Indexed: 01/31/2023]
Abstract
BACKGROUND Weakness is a common clinical symptom reported in individuals with chronic alcohol use disorder. However, it remains unclear whether low strength in these individuals is directly related to excessive ethanol intake, other deleterious factors (lifestyle, environment, genetics, etc.), or a combination of both. Therefore, we examined whether (and how) ethanol reduces the muscle's force-producing capacity using a controlled in vivo preclinical mouse model of excessive ethanol intake. METHODS To establish whether chronic ethanol consumption causes weakness, C57BL/6 female mice consumed 20% ethanol for 40 weeks (following a 2-week ethanol ramping period), and various measures of muscular force were quantified. Functional measures included all-limb grip strength and in vivo contractility of the left ankle dorsiflexors and plantarflexors. Once confirmed that mice consuming ethanol were weaker than age-matched controls, we sought to determine the potential neuromuscular mechanisms of muscle dysfunction by assessing neuromuscular excitation, muscle quantity, and muscle quality. RESULTS Mice consuming chronic ethanol were 13 to 16% weaker (p ≤ 0.016) than controls (i.e., mice consuming 100% water) with the negative impact of ethanol on voluntary grip strength (ƞ2 = 0.603) being slightly larger than that of electrically stimulated muscle contractility (ƞ2 = 0.482). Relative to controls, lean mass and muscle wet masses were 9 to 16% lower in ethanol-consuming mice (p ≤ 0.048, ƞ2 ≥ 0.268). No significant changes were observed between groups for indices of neuromuscular excitation at the level of the motor unit, neuromuscular junction, or plasmalemma (p ≥ 0.259, ƞ2 ≤ 0.097), nor was muscle quality altered after 40 weeks of 20% ethanol consumption (p ≥ 0.695, ƞ2 ≤ 0.012). CONCLUSIONS Together, these findings establish that chronic ethanol consumption in mice induces a substantial weakness in vivo that we interpret to be primarily due to muscle atrophy (i.e., reduced muscle quantity) and possibly, to a lesser degree, loss of central neural drive.
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Affiliation(s)
- Samantha E. Moser
- Honors Tutorial CollegeOhio UniversityAthensOhioUSA,Ohio Musculoskeletal and Neurological Institute (OMNI)Ohio UniversityAthensOhioUSA
| | - Austin M. Brown
- Honors Tutorial CollegeOhio UniversityAthensOhioUSA,Ohio Musculoskeletal and Neurological Institute (OMNI)Ohio UniversityAthensOhioUSA
| | - Brian C. Clark
- Ohio Musculoskeletal and Neurological Institute (OMNI)Ohio UniversityAthensOhioUSA,Department of Biomedical SciencesOhio UniversityAthensOhioUSA
| | - W. David Arnold
- Department of NeurologyThe Ohio State University Wexner Medical CenterColumbusOhioUSA,Department of Physical Medicine and RehabilitationThe Ohio State University Wexner Medical CenterColumbusOhioUSA,Department of NeuroscienceThe Ohio State University Wexner Medical CenterColumbusOhioUSA,Department of Physiology and Cell BiologyThe Ohio State University Wexner Medical CenterColumbusOhioUSA
| | - Cory W. Baumann
- Ohio Musculoskeletal and Neurological Institute (OMNI)Ohio UniversityAthensOhioUSA,Department of Biomedical SciencesOhio UniversityAthensOhioUSA
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8
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Alcohol Induces Zebrafish Skeletal Muscle Atrophy through HMGB1/TLR4/NF-κB Signaling. LIFE (BASEL, SWITZERLAND) 2022; 12:life12081211. [PMID: 36013390 PMCID: PMC9410481 DOI: 10.3390/life12081211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/04/2022] [Accepted: 08/06/2022] [Indexed: 11/17/2022]
Abstract
Excessive alcohol consumption can cause alcoholic myopathy, but the molecular mechanism is still unclear. In this study, zebrafish were exposed to 0.5% alcohol for eight weeks to investigate the effect of alcohol on skeletal muscle and its molecular mechanism. The results showed that the body length, body weight, cross-sectional area of the skeletal muscle fibers, Ucrit, and MO2max of the zebrafish were significantly decreased after alcohol exposure. The expression of markers of skeletal muscle atrophy and autophagy was increased, and the expression of P62 was significantly reduced. The content of ROS, the mRNA expression of sod1 and sod2, and the protein expression of Nox2 were significantly increased. In addition, we found that the inflammatory factors Il1β and Tnfα were significantly enriched in skeletal muscle, and the expression of the HMGB1/TLR4/NF-κB signaling axis was also significantly increased. In summary, in this study, we established a zebrafish model of alcohol-induced skeletal muscle atrophy and further elucidated its pathogenesis.
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9
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Banu S, Srivastava S, Mohammed A, Kushawah G, Sowpati DT, Mishra RK. Tissue-specific transcriptome recovery on withdrawal from chronic alcohol exposure in zebrafish. Alcohol 2021; 91:29-38. [PMID: 33038458 DOI: 10.1016/j.alcohol.2020.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 09/28/2020] [Accepted: 10/01/2020] [Indexed: 12/16/2022]
Abstract
Alcohol consumption can lead to a wide range of systemic disorders brought about by transcriptional changes. Recent studies have documented altered behavior and physiology in zebrafish exposed to alcohol. In this work, we have identified the changes in the zebrafish transcriptome in response to chronic alcohol exposure. We have further followed the extent of transcriptional recovery upon withdrawal from alcohol and found evidence of tissue-specific responses. Our results indicate a greater extent of recovery of the brain transcriptome compared to the liver. We identify two distinct classes of genes in response to withdrawal from alcohol exposure - those that recover their pre-alcohol expression profile versus those that retain altered expression even after the fish are removed from the alcohol environment. Finally, we have examined gender-specific responses to alcohol exposure in zebrafish and find evidence for distinct alcohol tolerance levels. Upon chronic alcohol exposure, a higher percentage of genes show perturbation in expression profile in males compared to females. Female fish also recover better with more genes regaining the control expression level upon withdrawal from alcohol. Overall, our work identifies genes and pathways perturbed by exposure to alcohol, and demonstrates the extent of gender- and tissue-specific transcriptional changes associated with chronic alcoholism and withdrawal.
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10
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Abstract
Both acute intoxication and longer-term cumulative ingestion of alcohol negatively impact the metabolic phenotype of both skeletal and cardiac muscle, independent of overt protein calorie malnutrition, resulting in loss of skeletal muscle strength and cardiac contractility. In large part, these alcohol-induced changes are mediated by a decrease in protein synthesis that in turn is governed by impaired activity of a protein kinase, the mechanistic target of rapamycin (mTOR). Herein, we summarize recent advances in understanding mTOR signal transduction, similarities and differences between the effects of alcohol on this central metabolic controller in skeletal muscle and in the heart, and the effects of acute versus chronic alcohol intake. While alcohol-induced alterations in global proteolysis via activation of the ubiquitin-proteasome pathway are equivocal, emerging data suggest alcohol increases autophagy in muscle. Further studies are necessary to define the relative contributions of these bidirectional changes in protein synthesis and autophagy in the etiology of alcoholic myopathy in skeletal muscle and the heart.
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Affiliation(s)
- Scot R Kimball
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA; ,
| | - Charles H Lang
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA; ,
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11
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Kant S, Davuluri G, Alchirazi KA, Welch N, Heit C, Kumar A, Gangadhariah M, Kim A, McMullen MR, Willard B, Luse DS, Nagy LE, Vasiliou V, Marini AM, Weiner ID, Dasarathy S. Ethanol sensitizes skeletal muscle to ammonia-induced molecular perturbations. J Biol Chem 2019; 294:7231-7244. [PMID: 30872403 DOI: 10.1074/jbc.ra118.005411] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 03/12/2019] [Indexed: 12/27/2022] Open
Abstract
Ethanol causes dysregulated muscle protein homeostasis while simultaneously causing hepatocyte injury. Because hepatocytes are the primary site for physiological disposal of ammonia, a cytotoxic cellular metabolite generated during a number of metabolic processes, we determined whether hyperammonemia aggravates ethanol-induced muscle loss. Differentiated murine C2C12 myotubes, skeletal muscle from pair-fed or ethanol-treated mice, and human patients with alcoholic cirrhosis and healthy controls were used to quantify protein synthesis, mammalian target of rapamycin complex 1 (mTORC1) signaling, and autophagy markers. Alcohol-metabolizing enzyme expression and activity in mouse muscle and myotubes and ureagenesis in hepatocytes were quantified. Expression and regulation of the ammonia transporters, RhBG and RhCG, were quantified by real-time PCR, immunoblots, reporter assays, biotin-tagged promoter pulldown with proteomics, and loss-of-function studies. Alcohol and aldehyde dehydrogenases were expressed and active in myotubes. Ethanol exposure impaired hepatocyte ureagenesis, induced muscle RhBG expression, and elevated muscle ammonia concentrations. Simultaneous ethanol and ammonia treatment impaired protein synthesis and mTORC1 signaling and increased autophagy with a consequent decreased myotube diameter to a greater extent than either treatment alone. Ethanol treatment and withdrawal followed by ammonia exposure resulted in greater impairment in muscle signaling and protein synthesis than ammonia treatment in ethanol-naive myotubes. Of the three transcription factors that were bound to the RhBG promoter in response to ethanol and ammonia, DR1/NC2 indirectly regulated transcription of RhBG during ethanol and ammonia treatment. Direct effects of ethanol were synergistic with increased ammonia uptake in causing dysregulated skeletal muscle proteostasis and signaling perturbations with a more severe sarcopenic phenotype.
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Affiliation(s)
- Sashi Kant
- From the Departments of Inflammation and Immunity
| | | | | | - Nicole Welch
- From the Departments of Inflammation and Immunity
| | - Claire Heit
- the Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | | | | | - Adam Kim
- From the Departments of Inflammation and Immunity
| | | | - Belinda Willard
- Metabolomic and Proteomics Core, Cleveland Clinic, Cleveland, Ohio 44195
| | | | - Laura E Nagy
- From the Departments of Inflammation and Immunity
| | - Vasilis Vasiliou
- the Department of Environmental Health Sciences, Yale School of Public Health, New Haven, Connecticut 06510
| | - Anna Maria Marini
- the Biology of Membrane Transport Laboratory, Department of Molecular Biology, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles CP300, 6041 Gosselies, Belgium
| | - I David Weiner
- the Division of Nephrology, Hypertension, and Renal Transplantation, Department of Medicine, School of Medicine, University of Florida, Gainesville, Florida 32610, and.,the Nephrology and Hypertension Section, North Florida/South Georgia Veterans Health System, Gainesville, Florida 32608
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12
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Gano A, Vore AS, Sammakia MN, Deak T. Assessment of Extracellular Cytokines in the Hippocampus of the Awake Behaving Rat Using Large-Molecule Microdialysis Combined with Multiplex Arrays After Acute and Chronic Ethanol Exposure. Alcohol Clin Exp Res 2019; 43:640-654. [PMID: 30667526 DOI: 10.1111/acer.13963] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 01/14/2019] [Indexed: 12/21/2022]
Abstract
BACKGROUND Studies have demonstrated persistent changes in central nervous system (CNS) cytokine gene expression following ethanol (EtOH) exposure. However, the low endogenous expression and short half-lives of cytokines in the CNS have made cytokine protein detection challenging. The goal of these studies was to establish parameters for use of large-molecule microdialysis and sensitive multiplexing technology for the simultaneous detection of brain cytokines, corticosterone (CORT), and EtOH concentrations in the awake behaving rat. METHODS Adult (P75+) male Sprague Dawley rats that were either naïve to EtOH (Experiment 1) or had a history of adolescent chronic intermittent EtOH (CIE; Experiment 2) were given an acute EtOH challenge during microdialysis. Experiment 1 examined brain EtOH concentrations, CORT and a panel of neuroimmune analytes, including cytokines associated with innate and adaptive immunity. The natural time course of changes in these cytokines was compared to the effects of an acute 1.5 or 3.0 g/kg intraperitoneal (i.p.) EtOH challenge. In Experiment 2, rats with a history of adolescent CIE or controls exposed to vehicle were challenged with 3.0 g/kg i.p. EtOH during microdialysis in adulthood, and a panel of cytokines was examined in parallel with brain EtOH concentrations and CORT. RESULTS The microdialysis procedure itself induced a cytokine-specific response that replicated across studies, specifically a sequential elevation of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and IL-10. Surprisingly, acute EtOH did not significantly alter this course of cytokine fluctuations in the hippocampus. However, a history of adolescent CIE showed drastic effects on multiple neuroimmune analytes when rechallenged with EtOH as adults. Rats with a history of adolescent EtOH displayed a severely blunted neuroimmune response in adulthood, evinced by suppressed IL-1β, IL-10, and TNF-α. CONCLUSIONS Together, these findings provide a methodological framework for assessment of cytokine release patterns, their modulation by EtOH, and the long-lasting changes to neuroimmune reactivity evoked by a history of adolescent CIE.
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Affiliation(s)
- Anny Gano
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, New York
| | - Andrew S Vore
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, New York
| | - Maryam N Sammakia
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, New York
| | - Terrence Deak
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, New York
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13
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Shenkman BS, Belova SP, Zinovyeva OE, Samkhaeva ND, Mirzoev TM, Vilchinskaya NA, Altaeva EG, Turtikova OV, Kostrominova TY, Nemirovskaya TL. Effect of Chronic Alcohol Abuse on Anabolic and Catabolic Signaling Pathways in Human Skeletal Muscle. Alcohol Clin Exp Res 2017; 42:41-52. [PMID: 29044624 DOI: 10.1111/acer.13531] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/10/2017] [Indexed: 12/20/2022]
Abstract
BACKGROUND Animal studies showed that alcoholic myopathy is characterized by the reduction in myofiber cross-sectional area (CSA) and by impaired anabolic signaling. The goal of this study was to compare changes in CSA and fiber type composition with modifications in anabolic and catabolic signaling pathways at the early stages of alcohol misuse in humans. METHODS Skeletal muscle samples from 7 male patients with chronic alcohol abuse (AL; 47.7 ± 2.0 years old; alcohol misuse duration 7.7 ± 0.6 years) were compared with muscle from a control group of 7 healthy men (C; 39.7 ± 5.0 years old). Biopsies from vastus lateralis muscles were taken and analyzed for the changes in fiber type composition, fiber CSA, and for the alterations in anabolic and catabolic signaling pathways. RESULTS AL patients did not have detectable clinical myopathy symptoms or muscle fiber atrophy, but the relative proportion of fast fibers was increased. There was a significant decrease in IGF-1 in plasma and IRS-1 protein content in muscle of AL group. Levels of total and phosphorylated p70S6K1, GSK3β, and p90RSK1 were not different between AL and C groups. Muscle of AL patients had increased mRNA expression of HSP70 and HSP90. A marker of anabolic pathway p-4E-BP1 was decreased, while catabolic markers (MuRF-1, MAFbx, ubiquitinated proteins) were increased in AL patients when compared with C group. CONCLUSIONS At the early stages of alcohol misuse in humans, changes in the regulation of anabolic and catabolic signaling pathways precede the development of skeletal muscle atrophy and manifestation of clinical symptoms of alcoholic myopathy.
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Affiliation(s)
| | | | - Olga E Zinovyeva
- Sechenov First Moscow State Medical University, Russian Ministry of Health, Moscow, Russia
| | - Nudlya D Samkhaeva
- Sechenov First Moscow State Medical University, Russian Ministry of Health, Moscow, Russia
| | | | | | | | | | - Tatiana Y Kostrominova
- Department of Anatomy and Cell Biology, Indiana University School of Medicine Northwest, Gary, Indiana
| | - Tatiana L Nemirovskaya
- Institute of Biomedical Problems, RAS, Moscow, Russia.,Faculty of Basic Medicine, Lomonosov Moscow State University, Moscow, Russia
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14
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Steiner JL, Lang CH. Alcoholic Cardiomyopathy: Disrupted Protein Balance and Impaired Cardiomyocyte Contractility. Alcohol Clin Exp Res 2017; 41:1392-1401. [PMID: 28425109 DOI: 10.1111/acer.13405] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 04/12/2017] [Indexed: 12/29/2022]
Abstract
Alcoholic cardiomyopathy (ACM) can develop after consumption of relatively large amounts of alcohol over time or from acute binge drinking. Of the many factors implicated in the etiology of ACM, chronic perturbation in protein balance has been strongly implicated. This review focused on recent contributions (since 2010) in the area of protein metabolism and cardiac function related to ACM. Data reviewed include that from in vitro and preclinical in vivo animal studies where alcohol or an oxidative metabolite was studied and outcome measures in either cardiomyocytes or whole heart pertaining to protein synthesis or degradation were reported. Additionally, studies on the contractile properties of cardiomyocytes were also included to link signal transduction with function. Methodological differences including the potential impact of sex, dosing, and duration/timing of alcohol administration are addressed. Acute and chronic alcohol consumption decreases cardiac protein synthesis and/or activation of proteins within the regulatory mammalian/mechanistic target of rapamycin complex pathway. Albeit limited, evidence suggests that myocardial protein degradation via the ubiquitin pathway is not altered, while autophagy may be enhanced in ACM. Alcohol impairs ex vivo cardiomyocyte contractility in relation to its metabolism and expression of proteins within the growth factor pathway. Dysregulation of protein metabolism, including the rate of protein synthesis and autophagy, may contribute to contractile deficits and is a hallmark feature of ACM meriting additional sex-inclusive, methodologically consistent studies.
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Affiliation(s)
- Jennifer L Steiner
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania
| | - Charles H Lang
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania
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15
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Duncan JW, Johnson S, Zhang X, Zheng B, Luo J, Ou XM, Stockmeier CA, Wang JM. Up-Regulation of PKR Signaling Pathway by Ethanol Displays an Age of Onset-Dependent Relationship. Alcohol Clin Exp Res 2016; 40:2320-2328. [PMID: 27647657 DOI: 10.1111/acer.13209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 08/01/2016] [Indexed: 12/16/2022]
Abstract
BACKGROUND Ethanol (EtOH) neurotoxicity can result in devastating effects on brain and behavior by disrupting homeostatic signaling cascades and inducing cell death. One such mechanism involves double-stranded RNA activated protein kinase (PKR), a primary regulator of protein translation and cell viability in the presence of a virus or other external stimuli. EtOH-mediated up-regulation of interferon-gamma (IFN-γ; the oxidative stress-inducible regulator of PKR), PKR, and its target, p53, are still being fully elucidated. METHODS Using Western blot analysis, immunofluorescence, and linear regression analyses, changes in the IFN-γ-PKR-p53 pathway following chronic EtOH treatment in the frontal cortex of rodents were examined. The role of PKR on cell viability was also assessed in EtOH-treated cells using PKR overexpression vector and PKR inhibitor (PKRI). RESULTS In rats chronically fed EtOH, PKR, phosphorylated PKR (p-PKR), IFN-γ, and p53 were significantly increased following chronic EtOH exposure. Linear regression revealed a significant correlation between IFN-γ and p-PKR protein levels, as well as p-PKR expression and age of EtOH exposure. Overexpression of PKR resulted in greater cell death, while use of PKRI enhanced cell viability in EtOH-treated cells. CONCLUSIONS Chronic EtOH exposure activates the IFN-γ-PKR-p53 pathway in the frontal cortex of rodents. p-PKR expression is greater in brains of rodents exposed to EtOH at earlier ages compared to later life, suggesting a mechanism by which young brains could be more susceptible to EtOH-related brain injury. PKR and p-PKR were also colocalized in neurons and astrocytes of rats. This study provides additional insight into biochemical mechanisms underlying alcohol use disorder related neuropathology and warrants further investigation of PKR as a potential pharmacotherapeutic target to combat EtOH-related neurotoxicity, loss of protein translation and brain injury.
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Affiliation(s)
- Jeremy W Duncan
- Program in Neuroscience , University of Mississippi Medical Center, Jackson, Mississippi.,Department of Psychiatry and Human Behavior , University of Mississippi Medical Center, Jackson, Mississippi
| | - Shakevia Johnson
- Department of Psychiatry and Human Behavior , University of Mississippi Medical Center, Jackson, Mississippi
| | - Xiao Zhang
- Program in Neuroscience , University of Mississippi Medical Center, Jackson, Mississippi.,Department of Psychiatry and Human Behavior , University of Mississippi Medical Center, Jackson, Mississippi
| | - Baoying Zheng
- Department of Pathology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Jia Luo
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, Kentucky.,Department of Internal Medicine, University of Kentucky, Lexington, Kentucky
| | - Xiao-Ming Ou
- Department of Psychiatry and Human Behavior , University of Mississippi Medical Center, Jackson, Mississippi
| | - Craig A Stockmeier
- Department of Psychiatry and Human Behavior , University of Mississippi Medical Center, Jackson, Mississippi
| | - Jun Ming Wang
- Program in Neuroscience , University of Mississippi Medical Center, Jackson, Mississippi. .,Department of Psychiatry and Human Behavior , University of Mississippi Medical Center, Jackson, Mississippi. .,Department of Pathology, University of Mississippi Medical Center, Jackson, Mississippi.
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16
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Molina PE, Amedee AM, Winsauer P, Nelson S, Bagby G, Simon L. Behavioral, Metabolic, and Immune Consequences of Chronic Alcohol or Cannabinoids on HIV/AIDs: Studies in the Non-Human Primate SIV Model. J Neuroimmune Pharmacol 2015; 10:217-32. [PMID: 25795088 PMCID: PMC4470723 DOI: 10.1007/s11481-015-9599-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 03/05/2015] [Indexed: 02/07/2023]
Abstract
HIV-associated mortality has been significantly reduced with antiretroviral therapy (ART), and HIV infection has become a chronic disease that frequently coexists with many disorders, including substance abuse (Azar et al. Drug Alcohol Depend 112:178-193, 2010; Phillips et al. J Gen Int Med 16:165, 2001). Alcohol and drugs of abuse may modify host-pathogen interactions at various levels including behavioral, metabolic, and immune consequences of HIV infection, as well as the ability of the virus to integrate into the genome and replicate in host cells. Identifying mechanisms responsible for these interactions is complicated by many factors, such as the tissue specific responses to viral infection, multiple cellular mechanisms involved in inflammatory responses, neuroendocrine and localized responses to infection, and kinetics of viral replication. An integrated physiological analysis of the biomedical consequences of chronic alcohol and drug use or abuse on disease progression is possible using rhesus macaques infected with simian immunodeficiency virus (SIV), a relevant model of HIV infection. This review will provide an overview of the data gathered using this model to show that chronic administration of two of the most commonly abused substances, alcohol and cannabinoids (Δ(9)-Tetrahydrocannabinol; THC), affect host-pathogen interactions.
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Affiliation(s)
- Patricia E Molina
- Department of Physiology, Louisiana State University Health Sciences Center, School of Medicine, 1901 Perdido Street, New Orleans, LA, 70112, USA,
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17
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Steiner JL, Lang CH. Dysregulation of skeletal muscle protein metabolism by alcohol. Am J Physiol Endocrinol Metab 2015; 308:E699-712. [PMID: 25759394 PMCID: PMC4420901 DOI: 10.1152/ajpendo.00006.2015] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 03/03/2015] [Indexed: 12/12/2022]
Abstract
Alcohol abuse, either by acute intoxication or prolonged excessive consumption, leads to pathological changes in many organs and tissues including skeletal muscle. As muscle protein serves not only a contractile function but also as a metabolic reserve for amino acids, which are used to support the energy needs of other tissues, its content is tightly regulated and dynamic. This review focuses on the etiology by which alcohol perturbs skeletal muscle protein balance and thereby over time produces muscle wasting and weakness. The preponderance of data suggest that alcohol primarily impairs global protein synthesis, under basal conditions as well as in response to several anabolic stimuli including growth factors, nutrients, and muscle contraction. This inhibitory effect of alcohol is mediated, at least in part, by a reduction in mTOR kinase activity via a mechanism that remains poorly defined but likely involves altered protein-protein interactions within mTOR complex 1. Furthermore, alcohol can exacerbate the decrement in mTOR and/or muscle protein synthesis present in other catabolic states. In contrast, alcohol-induced changes in muscle protein degradation, either global or via specific modulation of the ubiquitin-proteasome or autophagy pathways, are relatively inconsistent and may be model dependent. Herein, changes produced by acute intoxication versus chronic ingestion are contrasted in relation to skeletal muscle metabolism, and limitations as well as opportunities for future research are discussed. As the proportion of more economically developed countries ages and chronic illness becomes more prevalent, a better understanding of the etiology of biomedical consequences of alcohol use disorders is warranted.
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Affiliation(s)
- Jennifer L Steiner
- Department of Cellular and Molecular Physiology, Pennsylvania State College of Medicine, Hershey, Pennsylvania
| | - Charles H Lang
- Department of Cellular and Molecular Physiology, Pennsylvania State College of Medicine, Hershey, Pennsylvania
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18
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Steiner JL, Gordon BS, Lang CH. Moderate alcohol consumption does not impair overload-induced muscle hypertrophy and protein synthesis. Physiol Rep 2015; 3:3/3/e12333. [PMID: 25780086 PMCID: PMC4393167 DOI: 10.14814/phy2.12333] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Chronic alcohol consumption leads to muscle weakness and atrophy in part by suppressing protein synthesis and mTORC1-mediated signaling. However, it is unknown whether moderate alcohol consumption also prevents overload-induced muscle growth and related anabolic signaling. Hypertrophy of the plantaris muscle was induced by removal of a section of the gastrocnemius and soleus muscles from one leg of C57BL/6 adult male mice while the contralateral leg remained intact as the sham control. A nutritionally complete alcohol-containing liquid diet (EtOH) or isocaloric, alcohol-free liquid diet (Con) was provided for 14 days post-surgery. EtOH intake was increased progressively (day 1-5) before being maintained at ~20 g/day/kg BW. The plantaris muscle from the sham and OL leg was removed after 14 days at which time there was no difference in body weight between Con and EtOH-fed mice. OL increased muscle weight (90%) and protein synthesis (125%) in both Con and EtOH mice. The overload-induced increase in mTOR (Ser2448), 4E-BP1 (Thr37/46), S6K1 (Thr389), rpS6 (Ser240/244), and eEF2 (Thr56) were comparable in muscle from Con and EtOH mice. Modulation of signaling upstream of mTORC1 including REDD1 protein expression, Akt (Thr308), PRAS40 (Thr246), and ERK (Thr202/Tyr204) also did not differ between Con and EtOH mice. Markers of autophagy (ULK1, p62, and LC3) suggested inhibition of autophagy with overload and activation with alcohol feeding. These data show that moderate alcohol consumption does not impair muscle growth, and therefore imply that resistance exercise may be an effective therapeutic modality for alcoholic-related muscle disease.
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Affiliation(s)
- Jennifer L Steiner
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania
| | - Bradley S Gordon
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania
| | - Charles H Lang
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania
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19
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Steiner JL, Lang CH. Alcohol intoxication following muscle contraction in mice decreases muscle protein synthesis but not mTOR signal transduction. Alcohol Clin Exp Res 2015; 39:1-10. [PMID: 25623400 PMCID: PMC4308817 DOI: 10.1111/acer.12600] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 10/13/2014] [Indexed: 12/20/2022]
Abstract
BACKGROUND Alcohol (ethanol [EtOH]) intoxication antagonizes stimulation of muscle protein synthesis and mammalian target of rapamycin (mTOR) signaling. However, whether the anabolic response can be reversed when alcohol is consumed after the stimulus is unknown. METHODS A single bout of electrically stimulated muscle contractions (10 sets of 6 contractions) was induced in fasted male C57BL/6 mice 2 hours prior to alcohol intoxication. EtOH was injected intraperitoneally (3 g/kg), and the gastrocnemius/plantaris muscle complex was collected 2 hours later from the stimulated and contralateral unstimulated control leg. RESULTS Muscle contraction increased protein synthesis 28% in control mice, while EtOH abolished this stimulation-induced increase. Further, EtOH suppressed the rate of synthesis ~75% compared to control muscle irrespective of stimulation. This decrease was associated with impaired protein elongation as EtOH increased the phosphorylation of eEF2 Thr(56) . In contrast, stimulation-induced increases in mTOR protein complex-1 (mTORC1) (S6K1 Thr(421) /Ser(424) , S6K1 Thr(389) , rpS6 Ser(240/244) , and 4E-BP1 Thr(37/46) ) and mitogen-activated protein kinase (MAPK) (JNK Thr(183) /Tyr(185) , p38 Thr(180) /Tyr(182) , and rpS6S(235/236) ) signaling were not reversed by acute EtOH. CONCLUSIONS These data suggest that EtOH-induced decreases in protein synthesis in fasted mice may be independent of mTORC1 and MAPK signaling following muscle contraction and instead due to the antagonistic actions of EtOH on mRNA translation elongation. Therefore, EtOH suppresses the contraction-induced increase in protein synthesis, and over time has the potential to prevent skeletal muscle hypertrophy induced by repeated muscle contraction.
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Affiliation(s)
- Jennifer L. Steiner
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033
| | - Charles H. Lang
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033
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20
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Steiner JL, Lang CH. Alcohol impairs skeletal muscle protein synthesis and mTOR signaling in a time-dependent manner following electrically stimulated muscle contraction. J Appl Physiol (1985) 2014; 117:1170-9. [PMID: 25257868 DOI: 10.1152/japplphysiol.00180.2014] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Alcohol (EtOH) decreases protein synthesis and mammalian target of rapamycin (mTOR)-mediated signaling and blunts the anabolic response to growth factors in skeletal muscle. The purpose of the current investigation was to determine whether acute EtOH intoxication antagonizes the contraction-induced increase in protein synthesis and mTOR signaling in skeletal muscle. Fasted male mice were injected intraperitoneally with 3 g/kg EtOH or saline (control), and the right hindlimb was electrically stimulated (10 sets of 6 contractions). The gastrocnemius muscle complex was collected 30 min, 4 h, or 12 h after stimulation. EtOH decreased in vivo basal protein synthesis (PS) in the nonstimulated muscle compared with time-matched Controls at 30 min, 4 h, and 12 h. In Control, but not EtOH, PS was decreased 15% after 30 min. In contrast, PS was increased in Control 4 h poststimulation but remained unchanged in EtOH. Last, stimulation increased PS 10% in Control and EtOH at 12 h, even though the absolute rate remained reduced by EtOH. The stimulation-induced increase in the phosphorylation of S6K1 Thr(421)/Ser(424) (20-52%), S6K1 Thr(389) (45-57%), and its substrate rpS6 Ser(240/244) (37-72%) was blunted by EtOH at 30 min, 4 h, and 12 h. Phosphorylation of 4E-BP1 Ser(65) was also attenuated by EtOH (61%) at 4 h. Conversely, phosphorylation of extracellular signal-regulated kinase Thr(202)/Tyr(204) was increased by stimulation in Control and EtOH mice at 30 min but only in Control at 4 h. Our data indicate that acute EtOH intoxication suppresses muscle protein synthesis for at least 12 h and greatly impairs contraction-induced changes in synthesis and mTOR signaling.
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Affiliation(s)
- Jennifer L Steiner
- Department of Cellular and Molecular Physiology, Pennsylvania State College of Medicine, Hershey, Pennsylvania
| | - Charles H Lang
- Department of Cellular and Molecular Physiology, Pennsylvania State College of Medicine, Hershey, Pennsylvania
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21
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Borrisser-Pairó F, Antúnez E, Tobías E, Fernández-Solà J. Insulin-like growth factor 1 myocardial expression decreases in chronic alcohol consumption. Regen Med Res 2013; 1:3. [PMID: 25984322 PMCID: PMC4375930 DOI: 10.1186/2050-490x-1-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Accepted: 04/02/2013] [Indexed: 01/21/2023] Open
Abstract
Background Alcoholic cardiomyopathy (CMP) is one of the major complications of chronic excessive alcohol consumption. The pathogenic mechanisms implicated are diverse, inducing functional and structural changes in the myocardium. Insulin-like Growth Factor 1 (IGF-1) plays an important role in modulating the cell cycle, and helps the differentiation and proliferation of cardiac tissue inhibiting apoptosis. Experimental studies have suggested the role of IGF-1 in alcohol-induced cardiac damage. The aim of the present study was to determine the effect of chronic alcohol consumption on IGF-1 myocardial expression and to compare this expression in cases of hypertension and other cardiac diseases. Methods We studied heart samples from human organ donors: 10 healthy donors, 16 with hypertension, 23 with chronic alcohol consumption and 7 with other causes of cardiac disease. IGF-1 myocardial expression was evaluated with a specific immunohistochemistry assay using a semi-quantitative method. Results A significant decrease in IGF-1 myocardial expression was observed comparing all the cases included with control donors. This decrease in IGF-1 myocardial expression was significantly lower in the group of donors with chronic alcohol consumption compared to controls. On group evaluation according to the presence of CMP, donors with chronic alcohol consumption without CMP presented significantly lower IGF-1 expression than controls, whereas donors with chronic alcohol consumption with CMP showed a downward trend without achieving significance. Conclusions Chronic alcohol consumption significantly reduces IGF-1 myocardial expression. This decrease induced by alcohol is partially compensated in the presence of structural myocardial damage.
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Affiliation(s)
- Francesc Borrisser-Pairó
- Alcohol Research Unit. Hospital Clínic. Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS). Department of Medicine, University of Barcelona, Barcelona, Spain
| | - Emilia Antúnez
- Alcohol Research Unit. Hospital Clínic. Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS). Department of Medicine, University of Barcelona, Barcelona, Spain
| | - Ester Tobías
- Alcohol Research Unit. Hospital Clínic. Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS). Department of Medicine, University of Barcelona, Barcelona, Spain
| | - Joaquim Fernández-Solà
- Alcohol Research Unit. Hospital Clínic. Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS). Department of Medicine, University of Barcelona, Barcelona, Spain
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Dekeyser GJ, Clary CR, Otis JS. Chronic alcohol ingestion delays skeletal muscle regeneration following injury. Regen Med Res 2013; 1:2. [PMID: 25984321 PMCID: PMC4376340 DOI: 10.1186/2050-490x-1-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 12/21/2012] [Indexed: 12/17/2022] Open
Abstract
Background Chronic alcohol ingestion may cause severe biochemical and pathophysiological derangements to skeletal muscle. Unfortunately, these alcohol-induced events may also prime skeletal muscle for worsened, delayed, or possibly incomplete repair following acute injury. As alcoholics may be at increased risk for skeletal muscle injury, our goals were to identify the effects of chronic alcohol ingestion on components of skeletal muscle regeneration. To accomplish this, age- and gender-matched C57Bl/6 mice were provided normal drinking water or water that contained 20% alcohol (v/v) for 18–20 wk. Subgroups of mice were injected with a 1.2% barium chloride (BaCl2) solution into the tibialis anterior (TA) muscle to initiate degeneration and regeneration processes. Body weights and voluntary wheel running distances were recorded during the course of recovery. Muscles were harvested at 2, 7 or 14 days post-injection and assessed for markers of inflammation and oxidant stress, fiber cross-sectional areas, levels of growth and fibrotic factors, and fibrosis. Results Body weights of injured, alcohol-fed mice were reduced during the first week of recovery. These mice also ran significantly shorter distances over the two weeks following injury compared to uninjured, alcoholics. Injured TA muscles from alcohol-fed mice had increased TNFα and IL6 gene levels compared to controls 2 days after injury. Total protein oxidant stress and alterations to glutathione homeostasis were also evident at 7 and 14 days after injury. Ciliary neurotrophic factor (CNTF) induction was delayed in injured muscles from alcohol-fed mice which may explain, in part, why fiber cross-sectional area failed to normalize 14 days following injury. Gene levels of TGFβ1 were induced early following injury before normalizing in muscle from alcohol-fed mice compared to controls. However, TGFβ1 protein content was consistently elevated in injured muscle regardless of diet. Fibrosis was increased in injured, muscle from alcohol-fed mice at 7 and 14 days of recovery compared to injured controls. Conclusions Chronic alcohol ingestion appears to delay the normal regenerative response following significant skeletal muscle injury. This is evidenced by reduced cross-sectional areas of regenerated fibers, increased fibrosis, and altered temporal expression of well-described growth and fibrotic factors.
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Affiliation(s)
- Graham J Dekeyser
- Department of Kinesiology and Health, Georgia State University, Atlanta, GA 30322 USA
| | | | - Jeffrey S Otis
- Department of Kinesiology and Health, Georgia State University, Atlanta, GA 30322 USA
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23
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Manzardo AM, Gunewardena S, Butler MG. Over-expression of the miRNA cluster at chromosome 14q32 in the alcoholic brain correlates with suppression of predicted target mRNA required for oligodendrocyte proliferation. Gene 2013; 526:356-63. [PMID: 23747354 PMCID: PMC3816396 DOI: 10.1016/j.gene.2013.05.052] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 05/20/2013] [Accepted: 05/23/2013] [Indexed: 10/26/2022]
Abstract
We examined miRNA expression from RNA isolated from the frontal cortex (Broadman area 9) of 9 alcoholics (6 males, 3 females, mean age 48 years) and 9 matched controls using both the Affymetrix GeneChip miRNA 2.0 and Human Exon 1.0 ST Arrays to further characterize genetic influences in alcoholism and the effects of alcohol consumption on predicted target mRNA expression. A total of 12 human miRNAs were significantly up-regulated in alcohol dependent subjects (fold change≥1.5, false discovery rate (FDR)≤0.3; p<0.05) compared with controls including a cluster of 4 miRNAs (e.g., miR-377, miR-379) from the maternally expressed 14q32 chromosome region. The status of the up-regulated miRNAs was supported using the high-throughput method of exon microarrays showing decreased predicted mRNA gene target expression as anticipated from the same RNA aliquot. Predicted mRNA targets were involved in cellular adhesion (e.g., THBS2), tissue differentiation (e.g., CHN2), neuronal migration (e.g., NDE1), myelination (e.g., UGT8, CNP) and oligodendrocyte proliferation (e.g., ENPP2, SEMA4D1). Our data support an association of alcoholism with up-regulation of a cluster of miRNAs located in the genomic imprinted domain on chromosome 14q32 with their predicted gene targets involved with oligodendrocyte growth, differentiation and signaling.
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Affiliation(s)
- A M Manzardo
- Department of Psychiatry and Behavioral Sciences, University of Kansas School of Medicine, Kansas City, KS 66160, USA.
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24
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Waszkiewicz N, Szulc A, Zwierz K. Binge drinking-induced subtle myocardial injury. Alcohol Clin Exp Res 2013; 37:1261-3. [PMID: 23800345 DOI: 10.1111/acer.12208] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 05/17/2013] [Accepted: 05/19/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND Most of the clinical, histopathological, and biochemical studies consider the effect of chronic alcohol intoxication on myocardial injury. Much less attention has been paid to acute alcohol (binge drinking)-induced cardiotoxicity, even though alcohol binging is much more common than alcohol dependence. METHODS We briefly present some of the binge drinking-induced "holiday heart" effects. The literature was searched to find effects of alcohol on heart. RESULTS In binge drinking, the literature has demonstrated transient myocardial subtle changes in cardiac magnetic resonance, increased serological markers of myocardial injury and inflammation, abnormal cardiac rhythm, changes in other biochemical and ultrastructural indices of myocardial dysfunction, as well as changes in metabolism, blood pressure, heart rate, thrombosis/fibrinolysis processes, and coronary vasoconstriction. CONCLUSIONS Although acute low alcohol exposure has widely proven positive effect on myocardial function, heavy acute drinking frequent events are related to adverse cardiovascular effects.
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Islam A, Abraham P, Hapner CD, Deuster PA, Chen Y. Tissue-specific upregulation of HSP72 in mice following short-term administration of alcohol. Cell Stress Chaperones 2013; 18:215-22. [PMID: 23011927 PMCID: PMC3581633 DOI: 10.1007/s12192-012-0375-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 09/13/2012] [Accepted: 09/14/2012] [Indexed: 12/24/2022] Open
Abstract
Oxidative stress and cellular injury have been implicated in induction of HSP72 by alcohol. We investigated the association between HSP72 induction and oxidative stress in mouse tissues following short-term administration of high doses of alcohol and caffeine alone or in combination. Adult male C57BL/6J mice were gavaged with vehicle, alcohol (∼1.7 g/kg/day), caffeine (∼44 mg/kg/day), or alcohol plus caffeine once daily for ten consecutive days. Upon completion of the treatments, tissues were collected for structural and biochemical analyses. Alcohol alone caused mild to moderate lesions in heart, liver, and gastrocnemius muscle. Similar structural changes were observed following administration of alcohol and caffeine combined. Alcohol administration also led to decreased glutathione levels in all three tissues and reduced plasma superoxide dismutase capacity. In contrast, alcohol and caffeine in combination reduced glutathione levels only in liver and gastrocnemius muscle and had no effect on plasma superoxide dismutase. Significant elevations in HSP72 protein and mRNA and in HSF1 protein levels were noted only in liver by alcohol alone or in combination with caffeine. No significant changes in morphology and HSP72 were detected in any tissues tested following administration of caffeine alone. These results suggest that a redox mechanism is involved in the structural impairment caused by short-term high-dose alcohol. Oxidative tissue injury by alcohol may not be associated with tissue HSP72 induction. Induction of HSP72 in liver by alcohol is mediated at both the transcriptional and translational levels.
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Affiliation(s)
- Aminul Islam
- Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Preetha Abraham
- Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Christopher D. Hapner
- Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Patricia A. Deuster
- Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Yifan Chen
- Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
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Szachowicz-Petelska B, Skrzydlewska E, Figaszewski Z. Protective effect of black tea on integral membrane proteins in rat liver. ACTA ACUST UNITED AC 2013; 65:173-9. [DOI: 10.1016/j.etp.2011.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 06/14/2011] [Accepted: 08/18/2011] [Indexed: 01/14/2023]
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Impaired insulin/IGF signaling in experimental alcohol-related myopathy. Nutrients 2012; 4:1058-75. [PMID: 23016132 PMCID: PMC3448087 DOI: 10.3390/nu4081058] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/07/2012] [Accepted: 08/13/2012] [Indexed: 12/13/2022] Open
Abstract
Alcohol-related myopathy (Alc-M) is highly prevalent among heavy drinkers, although its pathogenesis is not well understood. We hypothesize that Alc-M is mediated by combined effects of insulin/IGF resistance and oxidative stress, similar to the effects of ethanol on liver and brain. We tested this hypothesis using an established model in which adult rats were pair-fed for 8 weeks with isocaloric diets containing 0% (N = 8) or 35.5% (N = 13) ethanol by caloric content. Gastrocnemius muscles were examined by histology, morphometrics, qRT-PCR analysis, and ELISAs. Chronic ethanol feeding reduced myofiber size and mRNA expression of IGF-1 polypeptide, insulin, IGF-1, and IGF-2 receptors, IRS-1, and IRS-2. Multiplex ELISAs demonstrated ethanol-associated inhibition of insulin, IRS-1, Akt, and p70S6K signaling, and increased activation of GSK-3β. In addition, ethanol-exposed muscles had increased 4-hydroxy-2-nonenal immunoreactivity, reflecting lipid peroxidation, and reduced levels of mitochondrial Complex IV, Complex V, and acetylcholinesterase. These results demonstrate that experimental Alc-M is associated with inhibition of insulin/IGF/IRS and downstream signaling that mediates metabolism and cell survival, similar to findings in alcoholic liver and brain degeneration. Moreover, the increased oxidative stress, which could be mediated by mitochondrial dysfunction, may have led to inhibition of acetylcholinesterase, which itself is sufficient to cause myofiber atrophy and degeneration.
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Hong-Brown LQ, Kazi AA, Lang CH. Mechanisms mediating the effects of alcohol and HIV anti-retroviral agents on mTORC1, mTORC2 and protein synthesis in myocytes. World J Biol Chem 2012; 3:110-20. [PMID: 22905289 PMCID: PMC3421109 DOI: 10.4331/wjbc.v3.i6.110] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 05/29/2012] [Accepted: 06/05/2012] [Indexed: 02/05/2023] Open
Abstract
Alcoholism and acquired immune deficiency syndrome are associated with severe muscle wasting. This impairment in nitrogen balance arises from increased protein degradation and a decreased rate of protein synthesis. The regulation of protein synthesis is a complex process involving alterations in the phosphorylation state and protein-protein interaction of various components of the translation machinery and mammalian target of rapamycin (mTOR) complexes. This review describes mechanisms that regulate protein synthesis in cultured C2C12 myocytes following exposure to either alcohol or human immunodeficiency virus antiretroviral drugs. Particular attention is given to the upstream regulators of mTOR complexes and the downstream targets which play an important role in translation. Gaining a better understanding of these molecular mechanisms could have important implications for preventing changes in lean body mass in patients with catabolic conditions or illnesses.
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Affiliation(s)
- Ly Q Hong-Brown
- Ly Q Hong-Brown, Abid A Kazi, Charles H Lang, Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, PA 17033, United States
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Frost RA, Lang CH. Multifaceted role of insulin-like growth factors and mammalian target of rapamycin in skeletal muscle. Endocrinol Metab Clin North Am 2012; 41:297-322, vi. [PMID: 22682632 PMCID: PMC3376019 DOI: 10.1016/j.ecl.2012.04.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This review describes the current literature on the interaction between insulin-like growth factors, endocrine hormones, and branched-chain amino acids on muscle physiology in healthy young individuals and during select pathologic conditions. Emphasis is placed on the mechanism by which physical and hormonal signals are transduced at the cellular level to either grow or atrophy skeletal muscle. The key role of the mammalian target of rapamycin and its ability to respond to hypertrophic and atrophic signals informs our understanding how a combination of physical, nutritional, and pharmacologic therapies may be used in tandem to prevent or ameliorate reductions in muscle mass.
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Affiliation(s)
- Robert A. Frost
- Associate Professor, Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey PA, 17033
- Professor and Vice Chairman, Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey PA, 17033
| | - Charles H. Lang
- Associate Professor, Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey PA, 17033
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Dobrzyńska I, Szachowicz-Petelska B, Skrzydlewska E, Figaszewski Z. Effect of L-carnitine on liver cell membranes in ethanol-intoxicated rats. Chem Biol Interact 2010; 188:44-51. [PMID: 20637186 DOI: 10.1016/j.cbi.2010.07.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 06/25/2010] [Accepted: 07/03/2010] [Indexed: 11/24/2022]
Abstract
Ethanol intoxication is characterized by changes in cell metabolism which alter the structure and function of cell membrane components, including phospholipids and integral membrane proteins. The interaction of food nutrients with ethanol may modulate alcohol toxicity. One such compound is l-carnitine (l-3-hydroxy-4-N,N,N-trimethylaminobutyrate), which is also an antioxidant. Here we investigate l-carnitine as an antioxidant and assess its effect on the composition and electrical charge of liver cell membranes in ethanol-intoxicated rats. Qualitative and quantitative phospholipid composition and the presence of integral membrane proteins were determined by high performance liquid chromatography (HPLC). Electrophoresis was used to determine the surface charge density of the rat liver cell membranes. Ethanol increased phospholipid levels and altered the level of integral proteins as determined by decreased phenylalanine (Phe), cysteine (Cys) and lysine (Lys). Ethanol significantly enhanced changes in the surface charge density of the liver cell membranes. l-Carnitine administration to ethanol-intoxicated rats significantly protects phospholipids and proteins against oxidative modifications. Therefore, the beneficial effect of l-carnitine may be connected to its ability to scavenge free radicals.
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Affiliation(s)
- Izabela Dobrzyńska
- Institute of Chemistry, University in Białystok, Al. Piłsudskiego 11/4, 15-443 Białystok, Poland
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Vongvatcharanon U, Kankoun W, Udomuksorn W, Kumarnsit E, Vongvatcharanon S. Effects of alcohol on the levels of parvalbumin in rat hearts. Acta Histochem 2010; 112:284-97. [PMID: 19285340 DOI: 10.1016/j.acthis.2009.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2009] [Revised: 01/29/2009] [Accepted: 02/02/2009] [Indexed: 11/18/2022]
Abstract
Chronic excessive alcohol administration has been reported to be associated with diastolic dysfunction. Parvalbumin (PV) is a calcium-binding protein present in cardiac myocytes and involved in mediating relaxation. Therefore, alteration of PV levels may affect relaxation in cardiac myocytes. This study investigated the effects of alcohol administration on the levels of PV in the rat heart. Male Wistar rats weighing 200-250 g were divided into 2 groups: control (C) and alcohol-treated groups. The control group was provided with distilled water and the alcohol groups were provided with either a low dose (LD, 2g/kg) or high dose of ethanol (HD, 5 g/kg) once daily for 21 days, 3 months or 6 months. The PV levels in the ventricles were investigated by immunohistochemistry and Western blot analysis. In the 21-day ethanol-treated groups, parvalbumin immunoreactivity (PV-ir) and protein levels were not different when compared to the C, LD and HD groups. In the 3-month ethanol-treated groups, PV-ir and PV protein levels were decreased in both the LD and HD groups compared to that of the control group. In the 6-month ethanol-treated groups, PV-ir and PV protein levels decreased significantly in both the LD and HD groups (P<0.05). This indicates that short-term ethanol treatment may not affect PV levels, whereas, long-term ethanol treatment clearly reduced PV levels. The decrease of PV was predominantly due to the direct toxic effects of alcohol rather than malabsorption caused by pathological changes in the duodenum and liver. The toxic effects of alcohol leading to a reduction of PV levels may lead to diastolic impairment.
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Affiliation(s)
- Uraporn Vongvatcharanon
- Department of Anatomy, Faculty of Science, Prince of Songkla University, Hat-Yai, Songkhla 90112, Thailand.
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Alcohols and Aldehydes. Clin Toxicol (Phila) 2010. [DOI: 10.3109/9781420092264-25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Owen DB, Chamberlain KT, Shishido S, Grow WA. Ethanol decreases agrin-induced acetylcholine receptor clustering in C2C12 myotube culture. Toxicol In Vitro 2009; 24:645-51. [PMID: 19800963 DOI: 10.1016/j.tiv.2009.09.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 09/11/2009] [Accepted: 09/26/2009] [Indexed: 11/16/2022]
Abstract
We investigated the effect of ethanol on skeletal muscle development using C2C12 cell culture. The ethanol concentrations of 10mM, 25mM, and 100mM, were tested because plasma samples of alcohol-dependent individuals fall within this range. We assessed two specific events in skeletal muscle development, the fusion of myoblasts to form myotubes and the acetylcholine receptor (AChR) clustering associated with neuromuscular synapse formation. We report that ethanol does not effect myotube formation or the viability of myoblasts or myotubes in C2C12 cell culture. However, ethanol does effect AChR clustering on C2C12 myotubes. As motor neurons approach skeletal muscle during development, agrin is released by motor neurons and induces AChR clustering on muscle fibers. In our experiments, agrin was applied to cell cultures during the period when myoblasts fuse to form myotubes. In cell cultures exposed to ethanol during myotube formation, agrin-induced AChR clustering was decreased compared to untreated cultures. In cell cultures exposed to ethanol during myoblast proliferation, with ethanol removed during myotube formation, agrin-induced AChR clustering was unaffected. We conclude that exposure to a physiologically relevant concentration of ethanol during the specific period of myotube formation decreases agrin-induced AChR clustering.
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Affiliation(s)
- David B Owen
- Department of Anatomy, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, United States
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Abstract
The development of alcoholic muscle disease, which affects both cardiac and skeletal muscle, leads to increased morbidity and mortality in patients who abuse alcohol. The disease pathology includes myocyte degeneration, loss of striations, and myofilament dissolution, which is consistent with alterations in structural and myofibrillar proteins. One explanation for the changes in myofibrillar architecture is that the expression of cellular proteins may be compromised by ethanol consumption. The dynamic balance of proteins in striated muscle is dependent upon rates of protein synthesis and protein degradation. We have shown that protein synthesis is depressed in striated muscle after either acute alcohol intoxication or chronic alcohol ingestion. The loss of myofibrillar proteins occurs prior to any detection of abnormal muscle function in vivo. It is therefore of major importance to evaluate the regulation of protein turnover after ethanol consumption. This review describes protocols to study protein synthesis either in vivo or under in vitro conditions. The methods can be modified for studies involving transgenic mice allowing mechanisms responsible for the defects in protein synthesis to be dissected.
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Differential Phosphorylation of Translation Initiation Regulators 4EBP1, S6k1, and Erk 1/2 Following Inhibition of Alcohol Metabolism in Mouse Heart. Cardiovasc Toxicol 2008; 8:23-32. [DOI: 10.1007/s12012-008-9012-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Accepted: 02/07/2008] [Indexed: 01/02/2023]
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36
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Fernandez-Solà J, Preedy VR, Lang CH, Gonzalez-Reimers E, Arno M, Lin JCI, Wiseman H, Zhou S, Emery PW, Nakahara T, Hashimoto K, Hirano M, Santolaria-Fernández F, González-Hernández T, Fatjó F, Sacanella E, Estruch R, Nicolás JM, Urbano-Márquez A. Molecular and cellular events in alcohol-induced muscle disease. Alcohol Clin Exp Res 2008; 31:1953-62. [PMID: 18034690 DOI: 10.1111/j.1530-0277.2007.00530.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Alcohol consumption induces a dose-dependent noxious effect on skeletal muscle, leading to progressive functional and structural damage of myocytes, with concomitant reductions in lean body mass. Nearly half of high-dose chronic alcohol consumers develop alcoholic skeletal myopathy. The pathogenic mechanisms that lie between alcohol intake and loss of muscle tissue involve multiple pathways, making the elucidation of the disease somewhat difficult. This review discusses the recent advances in basic and clinical research on the molecular and cellular events involved in the development of alcohol-induced muscle disease. The main areas of recent research interest on this field are as follows: (i) molecular mechanisms in alcohol exposed muscle in the rat model; (ii) gene expression changes in alcohol exposed muscle; (iii) the role of trace elements and oxidative stress in alcoholic myopathy; and (iv) the role of apoptosis and preapoptotic pathways in alcoholic myopathy. These aforementioned areas are crucial in understanding the pathogenesis of this disease. For example, there is overwhelming evidence that both chronic alcohol ingestion and acute alcohol intoxication impair the rate of protein synthesis of myofibrillar proteins, in particular, under both postabsorptive and postprandial conditions. Perturbations in gene expression are contributory factors to the development of alcoholic myopathy, as ethanol-induced alterations are detected in over 400 genes and the protein profile (i.e., the proteome) of muscle is also affected. There is supportive evidence that oxidative damage is involved in the pathogenesis of alcoholic myopathy. Increased lipid peroxidation is related to muscle fibre atrophy, and reduced serum levels of some antioxidants may be related to loss of muscle mass and muscle strength. Finally, ethanol induces skeletal muscle apoptosis and increases both pro- and antiapoptotic regulatory mechanisms.
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Vargas R, Lang CH. Alcohol accelerates loss of muscle and impairs recovery of muscle mass resulting from disuse atrophy. Alcohol Clin Exp Res 2007; 32:128-37. [PMID: 18028527 DOI: 10.1111/j.1530-0277.2007.00548.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Muscle disuse atrophy is observed in patients recovering from trauma and there is an increased risk and severity of injury in patients abusing alcohol (EtOH). However, the interaction of EtOH and disuse on muscle protein balance has not been examined. Therefore, the present study addressed the hypothesis that EtOH accelerates the disuse atrophy and/or impairs the accretion of muscle protein during muscle recovery. METHODS To address this aim, disuse atrophy was induced in rats by 3 days of unilateral hindlimb immobilization (casting), using the contralateral leg as control, with EtOH or saline being orally gavaged twice, each day during this period. In a separate study, EtOH-treated rats received Velcade to inhibit proteasomal degradation. Finally, in the last study, rats had 1 limb casted for 5 days, the cast removed, and EtOH or saline gavaged twice daily during a 5-day recovery period. Muscle protein metabolism was assessed using surrogate markers of protein synthesis [i.e., phosphorylation of 4E-binding protein 1 (BP1) and S6 kinase 1 (S6K1)] and protein degradation (i.e., mRNA content of the ubiquitin E3 ligases atrogin-1 and MuRF1). RESULTS Ethanol alone did not decrease muscle weight in the uncasted muscle. However, the loss of mass of immobilized muscle from EtOH-gavaged rats was 80% greater than in the animals not receiving EtOH. This atrophic response was not associated with a change in Akt, 4E-BP1 or S6K1 phosphorylation among groups. In contrast, immobilization alone increased both atrogin-1 and MuRF1 mRNA, and EtOH further increased their expression in immobilized muscle. The proteasome inhibitor Velcade attenuated atrophy produced by EtOH + disuse. When administered during the recovery period, EtOH prevented the normal accretion of muscle mass. This EtOH effect was associated with increased atrogin-1 mRNA, a reduction in 4E-BP1 and S6 phosphorylation, and an increased AMP-activated kinase phosphorylation. CONCLUSIONS Based on the changes in these surrogate markers, our data suggest that EtOH accelerates disuse atrophy by stimulating ubiquitin-mediated proteolysis, and blunts repletion of muscle protein during recovery from disuse by increasing proteolysis and decreasing protein synthesis.
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Affiliation(s)
- Roberto Vargas
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
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Poulsen MB, Jakobsen J, Aagaard NK, Andersen H. Motor performance during and following acute alcohol intoxication in healthy non-alcoholic subjects. Eur J Appl Physiol 2007; 101:513-23. [PMID: 17717682 DOI: 10.1007/s00421-007-0511-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2007] [Indexed: 11/29/2022]
Abstract
Chronic alcohol abuse has adverse effects on skeletal muscle, and reduced muscle strength is frequently seen in chronic alcoholics. In this study the acute effects of moderate alcohol intoxication on motor performance was evaluated in 19 non-alcoholic healthy subjects (10 women, 9 men). A randomised double-blinded placebo controlled design was applied to subjects receiving alcohol in juice and pure juice at two separate test periods. Isokinetic and isometric muscle strength and endurance were determined before, during, 24 and 48 h after the ingestion of alcohol in juice and juice (placebo). To detect a reduced activation of the central motor pathways superimposed external electrical stimulations during voluntary contractions were applied. Creatine kinase (CK) was measured to detect any alcohol-induced changes in sarcolemmal integrity. No change was seen in isokinetic as well as in isometric muscle performance during or following the alcohol intoxication as compared to the non-alcoholic condition. Also, no central activation failure was observed. No significant difference in CK increment was observed comparing the alcoholic- and non-alcoholic condition. In conclusion, a single episode of moderate alcohol intoxication (1,4 g/l) does not impair motor performance, and no accelerated exercise-induced muscle damage is seen.
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Affiliation(s)
- M B Poulsen
- Department of Neurology, Aarhus University Hospital, 8000, Aarhus C, Denmark.
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Ronis MJJ, Wands JR, Badger TM, de la Monte SM, Lang CH, Calissendorff J. Alcohol-induced disruption of endocrine signaling. Alcohol Clin Exp Res 2007; 31:1269-85. [PMID: 17559547 DOI: 10.1111/j.1530-0277.2007.00436.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
This article contains the proceedings of a symposium at the 2006 ISBRA meeting in Sydney Australia, organized and cochaired by Martin J. Ronis and Thomas M. Badger. The presentations were (1) Effect of long-term ethanol consumption on liver injury and repair, by Jack R. Wands; (2) Alcohol-induced insulin resistance in liver: potential roles in regulation of ADH expression, ethanol clearance, and alcoholic liver disease, by Thomas M. Badger; (3) Chronic gestational exposure to ethanol causes brain insulin and insulin-like growth factor resistance, by Suzanne M de la Monte; (4) Disruption of IGF-1 signaling in muscle: a mechanism underlying alcoholic myopathy, by Charles H. Lang; (5) The role of reduced plasma estradiol and impaired estrogen signaling in alcohol-induced bone loss, by Martin J. Ronis; and (6) Short-term influence of alcohol on appetite-regulating hormones in man, by Jan Calissendorff.
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Affiliation(s)
- Martin J J Ronis
- Arkansas Children's Nutrition Center, Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72202, USA.
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Lang CH, Frost RA, Vary TC. Skeletal muscle protein synthesis and degradation exhibit sexual dimorphism after chronic alcohol consumption but not acute intoxication. Am J Physiol Endocrinol Metab 2007; 292:E1497-506. [PMID: 17264221 DOI: 10.1152/ajpendo.00603.2006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Epidemiological evidence suggests alcoholic myopathy is more severe in females than males, but comparable animal studies are lacking that make elucidating the biochemical locus for this defect problematic. The present study determined whether skeletal muscle protein synthesis and markers of degradation exhibit a sexual dimorphic response to either chronic alcohol consumption or acute intoxication. Male and female rats were fed an alcohol-containing diet, pair-fed for 26 wk (chronic), or received an intraperitoneal injection of alcohol (acute). In males, chronic alcohol decreased gastrocnemius protein synthesis by 20%. This reduction was associated with a twofold increase in the inactive eukaryotic initiation factor (eIF) 4E.4E-binding protein 1 (4E-BP1) complex and a 60% reduction in the active eIF4E.eIF4G complex. This redistribution of eIF4E was associated with decreased phosphorylation of both 4E-BP1 and eIF4G (50-55%). The phosphorylation of ribosomal protein S6 was also reduced 60% in alcohol-consuming male rats. In contrast, neither rates of protein synthesis nor indexes of translation initiation in muscle were altered in alcohol-fed female rats despite blood alcohol levels comparable to males. Chronic alcohol ingestion did not alter atrogin-1 or muscle RING finger-1 mRNA content (biomarkers of muscle proteolysis) in males but increased their expression in females 50-100%. Acute alcohol intoxication produced a comparable decrease in muscle protein synthesis and translation initiation in both male and female rats. Our data demonstrate a sexual dimorphism for muscle protein synthesis, translation initiation, and proteolysis in response to chronic, but not acute, alcohol intoxication; however, they do not support evidence indicating females are more sensitive toward the development of alcoholic skeletal muscle myopathy.
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Affiliation(s)
- Charles H Lang
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, PA 17033, USA.
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Abstract
Underlying the pathogenesis of chronic disease is the state of oxidative stress. Oxidative stress is an imbalance in oxidant and antioxidant levels. If an overproduction of oxidants overwhelms the antioxidant defenses, oxidative damage of cells, tissues, and organs ensues. In some cases, oxidative stress is assigned a causal role in disease pathogenesis, whereas in others the link is less certain. Along with underlying oxidative stress, chronic disease is often accompanied by muscle wasting. It has been hypothesized that catabolic programs leading to muscle wasting are mediated by oxidative stress. In cases where disease is localized to the muscle, this concept is easy to appreciate. Transmission of oxidative stress from diseased remote organs to skeletal muscle is thought to be mediated by humoral factors such as inflammatory cytokines. This review examines the relationship between oxidative stress, chronic disease, and muscle wasting, and the mechanisms by which oxidative stress acts as a catabolic signal.
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Affiliation(s)
- Jennifer S Moylan
- Department of Physiology, University of Kentucky, 800 Rose Street, Room MS-509, Lexington, Kentucky 40536-0298, USA
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Hong-Brown LQ, Brown CR, Huber DS, Lang CH. Alcohol and indinavir adversely affect protein synthesis and phosphorylation of MAPK and mTOR signaling pathways in C2C12 myocytes. Alcohol Clin Exp Res 2006; 30:1297-307. [PMID: 16899032 DOI: 10.1111/j.1530-0277.2006.00157.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Alcohol and the antiretroviral drug indinavir (Ind) decrease protein synthesis in skeletal muscle under in vivo and in vitro conditions. The goal of the present study was to identify signaling mechanisms responsible for the inhibitory effect of ethanol (EtOH) and Ind on protein synthesis. METHODS C2C12 mouse myocytes were incubated with EtOH, Ind, or a combination of both for 24 hours. The rate of protein synthesis was determined by [35S]methionine/cysteine incorporation into cellular protein. Phosphorylation of eukaryotic initiation and elongation factors were quantitated by Western blot analysis to identify potential mechanisms for regulating translation. RESULTS Treatment of myocytes with Ind or EtOH for 24 hours decreased protein synthesis by 19 and 22%, respectively, while a 35% decline was observed in cells treated simultaneously with both agents. Mechanistically, treatment with EtOH or Ind decreased the phosphorylation of the S6 ribosomal protein, and this reduction was associated with decreased S6K1 and p90rsk phosphorylation. Ethanol also decreased the phosphorylation of ERK1/2, mTOR, and 4EBP1, while Ind only suppressed ERK1/2 phosphorylation. Both agents inhibited the phosphorylation of Mnk1 and its upstream regulator p38 MAPK, and they decreased the amount of the active eukaryotic initiation factor (eIF) 4G/eIF4E complex. Finally, EtOH and/or Ind increased phosphorylation of the eukaryotic elongation factor (eEF)-2 by 1.6- to 6-fold. The effects of these agents were not additive, although the combination did exert a greater effect on S6K1 and eEF2 phosphorylation. CONCLUSIONS Ethanol and Ind decreased protein synthesis in myocytes and this response was associated with changes in the phosphorylation of proteins that regulate translation initiation and elongation.
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Affiliation(s)
- Ly Q Hong-Brown
- Department of Cellular and Molecular Physiology (H166), Penn State University College of Medicine, Hershey, Pennsylvania 17033, USA.
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Vary TC, Kimball SR, Sumner A. Sex-dependent differences in the regulation of myocardial protein synthesis following long-term ethanol consumption. Am J Physiol Regul Integr Comp Physiol 2006; 292:R778-87. [PMID: 16946086 DOI: 10.1152/ajpregu.00203.2006] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Chronic heavy alcohol consumption alters cardiac structure and function. Controversies remain as to whether hearts from females respond to the chronic ethanol intake in a manner analogous to males. In particular, sex differences in the myocardial response to chronic alcohol consumption remain unresolved at the molecular level. The purpose of the present set of experiments was to determine whether alterations in cardiac structure and protein metabolism show sexual dimorphism following chronic alcohol consumption for 26 wk. In control animals, hearts from female rats showed lowered heart weights and had thinner ventricular walls compared with males. The smaller heart size was associated with a lower protein content that occurred in part from a reduced rate of protein synthesis. Chronic alcohol consumption in males, but not in females, caused a thinning of the ventricular wall and intraventricular septum, as assessed by echocardiography, correlating with the loss of heart mass. The alterations in cardiac size occurred, in part, through a lowering of the protein content secondary to a diminished rate of protein synthesis. The decreased rate of protein synthesis appeared related to a reduced assembly of active eukaryotic initiation factor (eIF)4G.eIF4E complex secondary to both a diminished phosphorylation of eIF4G and increased formation of inactive 4Ebinding protein (4EBP1).eIF4E complex. The latter effects occurred as a result of decreased phosphorylation of 4EBP1. None of these ethanol-induced alterations in hearts from males were observed in hearts from females. These data suggest that chronic alcohol-induced impairments in myocardial protein synthesis results, in part, from marked decreases in eIF4E.eIF4G complex formation in males. The failure of female rats consuming ethanol to show structural changes appears related to the inability of ethanol to affect the regulation protein synthesis to the same extent as their male counterparts.
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Affiliation(s)
- Thomas C Vary
- Department of Cellular and Molecular Physiology, Penn State University College of Medicine, H166, 500 University Dr., Hershey, PA 17033, USA.
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Chen G, Ma C, Bower KA, Ke Z, Luo J. Interaction between RAX and PKR Modulates the Effect of Ethanol on Protein Synthesis and Survival of Neurons. J Biol Chem 2006; 281:15909-15. [PMID: 16574643 DOI: 10.1074/jbc.m600612200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ethanol exposure inhibits protein synthesis and causes cell death in the developing central nervous system. The double-stranded RNA (dsRNA)-activated protein kinase (PKR), a serine/threonine protein kinase, plays an important role in translational regulation and cell survival. PKR has been well known for its anti-viral response. Upon activation by viral infection or dsRNA, PKR phosphorylates its substrate, the alpha-subunit of eukaryotic translation initiation factor-2 (eIF2alpha) leading to inhibition of translation initiation. It has recently been shown that, in the absence of a virus or dsRNA, PKR can be activated by direct interactions with its protein activators, PACT, or its mouse homologue, RAX. We have demonstrated that exposure to ethanol increased the phosphorylation of PKR and eIF2alpha in the developing cerebellum. The effect of ethanol on PKR/eIF2alpha phosphorylation positively correlated to the expression of PACT/RAX in cultured neuronal cells. Using PKR inhibitors and PKR null mouse fibroblasts, we verified that ethanol-induced eIF2alpha phosphorylation was mediated by PKR. Overexpression of a wild-type RAX dramatically enhanced sensitivity to ethanol-induced PKR/eIF2alpha phosphorylation, as well as translational inhibition and cell death. In contrast, overexpression of a mutant (S18A) RAX inhibited ethanol-mediated PKR/eIF2alpha activation. Ethanol promoted PKR and RAX association in cells expressing wild-type RAX but not in cells expressing S18A RAX. S18A RAX functioned as a dominant negative protein and blocked ethanol-induced inhibition of protein synthesis and cell death. Our results suggest that the interactions between PKR and PACT/RAX modulate the effect of ethanol on protein synthesis and cell survival in the central nervous system.
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Affiliation(s)
- Gang Chen
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University School of Medicine, Robert C. Byrd Health Sciences Center, Morgantown, West Virginia 26506, USA
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Frost RA, Nystrom G, Burrows PV, Lang CH. Temporal differences in the ability of ethanol to modulate endotoxin-induced increases in inflammatory cytokines in muscle under in vivo conditions. Alcohol Clin Exp Res 2006; 29:1247-56. [PMID: 16046881 DOI: 10.1097/01.alc.0000171935.06914.5d] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Acute alcohol (EtOH) intoxication may both antagonize and potentiate the ability of monocytes/macrophages to respond to endotoxin (lipopolysaccharide [LPS]). The suppressive effects of EtOH predominate when the duration between EtOH and LPS administration is relatively short, whereas sensitization is observed under conditions when there is a relatively longer delay between EtOH and LPS exposure. Striated muscle is now recognized to possess components of both the afferent and efferent limbs of the innate immune system. The aim of the present study was to determine whether the interval between EtOH and LPS administration differentially affects the mRNA content for selected elements of the innate immune response in skeletal and cardiac muscle and to compare such changes with those occurring in liver and spleen. METHODS The content of mRNA for interleukin (IL)-6, IL-1beta, tumor necrosis factor (TNF)-alpha, and high-mobility group box (HMGB)-1, as well as toll-like receptors (TLRs)-2 and -4, were measured in gastrocnemius, heart, liver and spleen from rats orally gavaged with EtOH and then injected with LPS either two or 24 hr thereafter. RESULTS EtOH intoxication two hr before LPS acutely suppressed the increased IL-6 mRNA in all tissues and antagonized the increase in plasma and tissue IL-6 protein concentration. Similarly, EtOH blunted the LPS-induced increase in tissue mRNA expression of TNF-alpha and IL-1beta. In contrast, when LPS was given 24 hr after EtOH, the increased IL-6 in striated muscle, but not in liver or spleen, was selectively potentiated. An enhanced LPS responsiveness was also observed for the late-phase cytokine HMGB1 in all tissues; however, the increased tissue expression of TNF-alpha and IL-1beta induced by LPS was not augmented. TLR4 mRNA was decreased in both heart and spleen (but unaltered in skeletal muscle and liver) of rats injected with LPS, and this change was prevented by pretreatment with EtOH. In contrast, EtOH alone increased TLR-2 mRNA content of heart, liver, and spleen but not muscle. LPS also markedly increased TLR2 mRNA in the same three tissues under control conditions, but this increase was attenuated by EtOH administered either two or 24 hr before LPS. CONCLUSIONS Under in vivo conditions, the interval between EtOH exposure and LPS differentially affected the synthesis of various cytokines. In this regard, EtOH administered within two hr of LPS generally suppressed IL-6, IL-1beta, and TNF-alpha mRNAs in muscle, heart, liver, and spleen. Delaying the exposure of animals to LPS for 24 hr after EtOH, however, accentuated the increase in IL-6 and HMGB1, and for IL-6, this increased sensitivity appeared localized to striated muscle.
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Affiliation(s)
- Robert A Frost
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
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Lang CH, Frost RA, Summer AD, Vary TC. Molecular mechanisms responsible for alcohol-induced myopathy in skeletal muscle and heart. Int J Biochem Cell Biol 2005; 37:2180-95. [PMID: 15982919 DOI: 10.1016/j.biocel.2005.04.013] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2005] [Revised: 04/13/2005] [Accepted: 04/27/2005] [Indexed: 11/29/2022]
Abstract
Chronic alcohol abuse has the potential to modulate striated muscle physiology and function. The skeletal muscle alcoholic myopathy is characterized by muscle weakness and difficulties in gait and locomotion, while chronic alcohol consumption ultimately leads to a decrease in cardiac contractility and output. In both tissues a loss of protein mass results in part from a decreased protein synthesis that initially manifests as a defect in translational efficiency. This review focuses on recent developments in understanding the cellular and molecular mechanisms by which alcohol impairs mRNA translation in skeletal and cardiac muscle, including identification of the signaling pathways and biochemical sites negatively impacted. Defective signaling potentially results from resistance to the normal stimulating effects of anabolic hormones (insulin and insulin-like growth factor-I) and nutrients (leucine) as well as increased production of several negative regulators of muscle mass. Overall, the biochemical mechanisms contributing to the pathogenesis of loss of skeletal and cardiac muscle are reviewed.
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Affiliation(s)
- Charles H Lang
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
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Hong-Brown LQ, Pruznak AM, Frost RA, Vary TC, Lang CH. Indinavir alters regulators of protein anabolism and catabolism in skeletal muscle. Am J Physiol Endocrinol Metab 2005; 289:E382-90. [PMID: 15827064 DOI: 10.1152/ajpendo.00591.2004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The HIV protease inhibitor indinavir adversely impairs carbohydrate and lipid metabolism, whereas its influence on protein metabolism under in vivo conditions remains unknown. The present study tested the hypothesis that indinavir also decreases basal protein synthesis and impairs the anabolic response to insulin in skeletal muscle. Indinavir was infused intravenously for 4 h into conscious rats, at which time the homeostasis model assessment of insulin resistance was increased. Indinavir decreased muscle protein synthesis by 30%, and this reduction was due to impaired translational efficiency. To identify potential mechanisms responsible for regulating mRNA translation, several eukaryotic initiation factors (eIFs) were examined. Under basal fasted conditions, there was a redistribution of eIF4E from the active eIF4E.eIF4G complex to the inactive eIF4E.4E-BP1 complex, and this change was associated with a marked decrease in the phosphorylation of 4E-BP1 in muscle. Likewise, indinavir decreased constitutive phosphorylation of eIF4G and mTOR in muscle, but not S6K1 or the ribosomal protein S6. In contrast, the ability of a maximally stimulating dose of insulin to increase the phosphorylation of PKB, 4E-BP1, S6K1, or mTOR was not altered 20 min after intravenous injection. Indinavir increased mRNA expression of the ubiquitin ligase MuRF1, but the plasma concentration of 3-methylhistidine remained unaltered. These indinavir-induced changes were associated with a marked reduction in the plasma testosterone concentration but were independent of changes in plasma levels of IGF-I, corticosterone, TNF-alpha, or IL-6. In conclusion, indinavir acutely impairs basal protein synthesis and translation initiation in skeletal muscle but, in contrast to muscle glucose uptake, does not impair insulin-stimulated signaling of protein synthetic pathways.
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Affiliation(s)
- Ly Q Hong-Brown
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
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Vary TC, Deiter G. Long-term alcohol administration inhibits synthesis of both myofibrillar and sarcoplasmic proteins in heart. Metabolism 2005; 54:212-9. [PMID: 15690316 DOI: 10.1016/j.metabol.2004.08.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Alcohol decreases the rate of protein synthesis in cardiac muscle. We investigated the effects of feeding rats a diet containing alcohol for 16 weeks on the myocardial synthesis of myofibrillar and sarcoplasmic (non-myofibrillar) proteins. Alcohol administration decreased the overall rate of protein synthesis in cardiac muscle by 22% compared with controls (P < .05). The rate of synthesis of proteins in the myofibrillar and sarcoplasmic fractions was diminished proportionately after feeding a diet containing alcohol (P < .05). We examined the effects of diminished rates of protein synthesis on the expression of myofibrillar and non-myofibrillar proteins. The cellular content of actin and alpha -myosin heavy chain isoform was significantly reduced and there was an increase in the beta -myosin heavy chain isoform after feeding rats a diet containing alcohol. The reduced expression of myosin heavy chain isoform and actin did not result from a decreased abundance of messenger RNA for either of these proteins. The myocardial content of troponin C and T was unchanged whereas that of troponin I was increased. Ethanol administration reduced the expression of eEF2 and the inducible form of the 70-kDa heat shock protein, whereas the cognate form of the 70-kDa heat shock protein was unaffected in a non-myofibrillar-enriched fraction of cardiac muscle. These results suggest that (1) the reduced protein content observed in the heart after feeding a diet containing alcohol is a consequence of reduced synthesis of both myofibrillar and sarcoplasmic proteins, and (2) the expression of both actin and alpha-myosin heavy chain isoform is affected independently of the messenger RNA content of the proteins. We conclude that translational control mechanisms appear to be important in regulating the expression of myocardial proteins during long-term ethanol intoxication.
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Affiliation(s)
- Thomas C Vary
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
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Vary TC, Deiter G, Goodman SA. Acute alcohol intoxication enhances myocardial eIF4G phosphorylation despite reducing mTOR signaling. Am J Physiol Heart Circ Physiol 2005; 288:H121-8. [PMID: 15388509 DOI: 10.1152/ajpheart.00440.2004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Acute alcohol intoxication impairs myocardial protein synthesis in rats, secondary to a diminished mRNA translational efficiency. Decreased mRNA translational efficiency occurs through altered regulation of peptide chain initiation. The purpose of the present set of experiments was to determine whether acute alcohol intoxication alters the phosphorylation state of eukaryotic initiation factor (eIF) 4G, eIF4G·eIF4E complex formation, and the mammalian target of rapamycin (mTOR) signaling pathway in the heart. Acute alcohol intoxication was induced by injection of alcohol (75 mmol/kg body wt ip). Control animals received an equal volume of saline. Alcohol administration enhanced phosphorylation of eIF4G (Ser1108) approximately threefold. Alcohol administration lowered formation of the active eIF4G·eIF4E complex by >90%, whereas it increased the abundance of the inactive 4E-binding protein 1 (4E-BP1)·eIF4E complex by ∼160%. Phosphorylation of mTOR on Ser2448and Ser2481was decreased by 50%. Reduced mTOR phosphorylation did not result from decreased phosphorylation of PKB. Phosphorylation of 4E-BP1 and S6 kinase 1 (Thr389), downstream targets of mTOR, were also reduced after acute alcohol administration. These data suggest that acute alcohol-induced impairments in myocardial mRNA translation initiation result, in part, from marked decreases in eIF4G·eIF4E complex formation, which appear to be independent of changes in phosphorylation of eIF4G but dependent on mTOR.
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Affiliation(s)
- Thomas C Vary
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, H166, 500 Univ. Dr., Hershey, PA 17033, USA.
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Lang CH, Pruznak AM, Deshpande N, Palopoli MM, Frost RA, Vary TC. Alcohol Intoxication Impairs Phosphorylation of S6K1 and S6 in Skeletal Muscle Independently of Ethanol Metabolism. Alcohol Clin Exp Res 2004; 28:1758-67. [PMID: 15547464 DOI: 10.1097/01.alc.0000145787.66405.59] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND The purpose of this study was to characterize the ability of alcohol to suppress insulin-like growth factor (IGF)-I stimulation of ribosomal S6 kinase 1 (S6K1) and 4E-BP1 phosphorylation, which are central elements in the signal transduction pathway used to coordinate the protein synthetic response and may contribute to the development of alcoholic myopathy. METHODS In vivo studies examined the dose and time dependency of the ability of alcohol to impair signal transduction under basal and IGF-I-stimulated conditions. Additional studies examined the effect of gender, nutritional state, and route of alcohol administration. A separate study determined the direct effects of alcohol on muscle metabolism by using the isolated perfused hindlimb preparation. RESULTS The phosphorylation of S6K1 and S6 in muscle was increased after injection of IGF-I in control rats. In contrast, IGF-I failed to stimulate S6K1 or S6 phosphorylation 2.5 hr after intraperitoneal administration of alcohol when the blood alcohol concentration was increased between approximately 165 and 300 mg/dl. With a maximal suppressive dose of alcohol, the inhibitory effect on S6K1/S6 phosphorylation was observed as early as 1 hr and for up to 8 hr. The ability of alcohol to impair phosphorylation of S6K1 and S6 was independent of gender (male versus female), nutritional status (fed versus fasted), and route of alcohol administration (intraperitoneal versus oral). Furthermore, the suppressive effect of alcohol was still observed in rats pretreated with 4-methylpyrazole, suggesting that the response was independent of the oxidative metabolism of ethanol. The direct effect of alcohol on IGF-stimulated S6K1/S6 phosphorylation was also present when the isolated hindlimb was perfused in situ with buffer containing alcohol. In contrast to S6K1, acute alcohol intoxication did not consistently impair the ability of IGF-I to stimulate 4E-BP1 phosphorylation under any of the experimental conditions. CONCLUSIONS These data indicate that acute alcohol intoxication selectively impairs IGF-I signaling via S6K1, but not 4E-BP1, and that this defect is independent of gender, nutritional state, route of administration, and alcohol metabolism. The IGF-I resistance may represent a participating mechanism by which alcohol directly limits the translation of selected messenger RNAs and, ultimately, protein synthesis in skeletal muscle.
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Affiliation(s)
- Charles H Lang
- Pennsylvania State College of Medicine, Department of Cellular and Molecular Physiology (H166), Hershey, PA 17033, USA.
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