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Crewther BT, Pastuszak A, Cook CJ, Staniak Z. Disaggregating the influence of maturity status on training, anthropometric, performance, skeletal periphery, and hormonal factors in athletic boys. Physiol Behav 2024; 278:114502. [PMID: 38395323 DOI: 10.1016/j.physbeh.2024.114502] [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: 01/22/2024] [Revised: 02/19/2024] [Accepted: 02/20/2024] [Indexed: 02/25/2024]
Abstract
Maturity offset (i.e., age from peak height velocity [PHV]) is widely used to assess maturational status among youth athletes, but details on the skeletal periphery, hormones and training factors are lacking. More precision is also needed to explicate the timing, tempo, and sequence of growth-related events. These gaps were addressed in a cross-sectional study. One hundred and two athletic boys (aged 14.1 ± 0.5 years) were evaluated for training details, salivary testosterone and cortisol, height, body mass, body mass index, body fat, fat-free mass (FFM), hand and carpal bone area, bone mineral content (BMC) and density (BMD), and countermovement jump performance. Participants were assigned to circa-PHV (N = 56) and post-PHV (N = 46) groups for comparisons, before data pooling and disaggregation using generalized additive and linear regression models. The older post-PHV group had a larger body size, more testosterone, and better performance and skeletal outcomes, whilst weekly training and school-based exercise favored the younger circa-PHV group (all p < 0.001). Smoother plots verified these differences via linear, or weakly non-linear, associations. Maturity offset was predicted (R2 = 0.848) by the linear combination of FFM (42.0 % relative contribution), hand BMD (31.5 %), chronological age (16.0 %), testosterone (6.7 %), and training hours (3.8 %). In conclusion, athletic boys who presented at different stages of maturity (-0.98 to 2.84 years from PHV) also differed on many developmental features. Most variables increased at constant, or near-constant, tempo with a higher maturity offset, with FFM and hand BMD emerging as the strongest linear predictors of maturational status.
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Affiliation(s)
- Blair T Crewther
- Institute of Sport - National Research Institute, Warsaw, Poland; Biomedical Science, School of Science and Technology, University of New England, Armidale, Australia.
| | - Anna Pastuszak
- Institute of Sport - National Research Institute, Warsaw, Poland
| | - Christian J Cook
- Biomedical Science, School of Science and Technology, University of New England, Armidale, Australia; Hamlyn Centre, Imperial College, London, UK
| | - Zbigniew Staniak
- Institute of Sport - National Research Institute, Warsaw, Poland
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2
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Antinozzi C, Duranti G, Ceci R, Lista M, Sabatini S, Caporossi D, Di Luigi L, Sgrò P, Dimauro I. Hydrogen Peroxide Stimulates Dihydrotestosterone Release in C2C12 Myotubes: A New Perspective for Exercise-Related Muscle Steroidogenesis? Int J Mol Sci 2022; 23:ijms23126566. [PMID: 35743011 PMCID: PMC9223901 DOI: 10.3390/ijms23126566] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/06/2022] [Accepted: 06/09/2022] [Indexed: 02/05/2023] Open
Abstract
Skeletal muscle is a tissue that has recently been recognized for its ability to produce androgens under physiological conditions. The steroidogenesis process is known to be negatively influenced by reactive oxygen species (ROS) in reproductive Leydig and ovary cells, while their effect on muscle steroidogenesis is still an unexplored field. Muscle cells are continuously exposed to ROS, resulting from both their metabolic activity and the surrounding environment. Interestingly, the regulation of signaling pathways, induced by mild ROS levels, plays an important role in muscle fiber adaptation to exercise, in a process that also elicits a significant modulation in the hormonal response. The aim of the present study was to investigate whether ROS could influence steroidogenesis in skeletal muscle cells by evaluating the release of testosterone (T) and dihydrotestosterone (DHT), as well as the evaluation of the relative expression of the key steroidogenic enzymes 5α-reductase, 3β-hydroxysteroid dehydrogenase (HSD), 17β-HSD, and aromatase. C2C12 mouse myotubes were exposed to a non-cytotoxic concentration of hydrogen peroxide (H2O2), a condition intended to reproduce, in vitro, one of the main stimuli linked to the process of homeostasis and adaptation induced by exercise in skeletal muscle. Moreover, the influence of tadalafil (TAD), a phosphodiesterase 5 inhibitor (PDE5i) originally used to treat erectile dysfunction but often misused among athletes as a "performance-enhancing" drug, was evaluated in a single treatment or in combination with H2O2. Our data showed that a mild hydrogen peroxide exposure induced the release of DHT, but not T, and modulated the expression of the enzymes involved in steroidogenesis, while TAD treatment significantly reduced the H2O2-induced DHT release. This study adds a new piece of information about the adaptive skeletal muscle cell response to an oxidative environment, revealing that hydrogen peroxide plays an important role in activating muscle steroidogenesis.
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Affiliation(s)
- Cristina Antinozzi
- Endocrinology Unit, Department of Movement, Human and Health Sciences, Università degli Studi di Roma “Foro Italico”, Piazza Lauro De Bosis 6, 00135 Roma, Italy; (C.A.); (M.L.); (L.D.L.)
| | - Guglielmo Duranti
- Laboratory of Biochemistry of Movement, Department of Movement, Human and Health Sciences, Università degli Studi di Roma “Foro Italico”, Piazza Lauro De Bosis 6, 00135 Roma, Italy; (R.C.); (S.S.)
- Correspondence: (G.D.); (P.S.)
| | - Roberta Ceci
- Laboratory of Biochemistry of Movement, Department of Movement, Human and Health Sciences, Università degli Studi di Roma “Foro Italico”, Piazza Lauro De Bosis 6, 00135 Roma, Italy; (R.C.); (S.S.)
| | - Marco Lista
- Endocrinology Unit, Department of Movement, Human and Health Sciences, Università degli Studi di Roma “Foro Italico”, Piazza Lauro De Bosis 6, 00135 Roma, Italy; (C.A.); (M.L.); (L.D.L.)
| | - Stefania Sabatini
- Laboratory of Biochemistry of Movement, Department of Movement, Human and Health Sciences, Università degli Studi di Roma “Foro Italico”, Piazza Lauro De Bosis 6, 00135 Roma, Italy; (R.C.); (S.S.)
| | - Daniela Caporossi
- Laboratory of Biology and Human Genetic, Department of Movement, Human and Health Sciences, Università degli Studi di Roma “Foro Italico”, Piazza Lauro De Bosis 6, 00135 Roma, Italy; (D.C.); (I.D.)
| | - Luigi Di Luigi
- Endocrinology Unit, Department of Movement, Human and Health Sciences, Università degli Studi di Roma “Foro Italico”, Piazza Lauro De Bosis 6, 00135 Roma, Italy; (C.A.); (M.L.); (L.D.L.)
| | - Paolo Sgrò
- Endocrinology Unit, Department of Movement, Human and Health Sciences, Università degli Studi di Roma “Foro Italico”, Piazza Lauro De Bosis 6, 00135 Roma, Italy; (C.A.); (M.L.); (L.D.L.)
- Correspondence: (G.D.); (P.S.)
| | - Ivan Dimauro
- Laboratory of Biology and Human Genetic, Department of Movement, Human and Health Sciences, Università degli Studi di Roma “Foro Italico”, Piazza Lauro De Bosis 6, 00135 Roma, Italy; (D.C.); (I.D.)
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3
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Shi H, Cheer K, Simanainen U, Lesmana B, Ma D, Hew JJ, Parungao RJ, Li Z, Cooper MS, Handelsman DJ, Maitz PK, Wang Y. The contradictory role of androgens in cutaneous and major burn wound healing. BURNS & TRAUMA 2021; 9:tkaa046. [PMID: 33928173 PMCID: PMC8058007 DOI: 10.1093/burnst/tkaa046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/31/2020] [Indexed: 01/25/2023]
Abstract
Wound healing is a complex process involving four overlapping phases: haemostasis, inflammation, cell recruitment and matrix remodeling. In mouse models, surgical, pharmacological and genetic approaches targeting androgen actions in skin have shown that androgens increase interleukin-6 and tumor necrosis factor-α production and reduce wound re-epithelization and matrix deposition, retarding cutaneous wound healing. Similarly, clinical studies have shown that cutaneous wound healing is slower in men compared to women. However, in major burn injury, which triggers not only local wound-healing processes but also systemic hypermetabolism, the role of androgens is poorly understood. Recent studies have claimed that a synthetic androgen, oxandrolone, increases protein synthesis, improves lean body mass and shortens length of hospital stay. However, the possible mechanisms by which oxandrolone regulates major burn injury have not been reported. In this review, we summarize the current findings on the roles of androgens in cutaneous and major burn wound healing, as well as androgens as a potential therapeutic treatment option for patients with major burn injuries.
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Affiliation(s)
- Huaikai Shi
- Burns Research Group, ANZAC Research Institute, University of Sydney, Concord Hospital, Gate, 3 Hospital road, Concord, NSW 2139, Australia
| | - Kenny Cheer
- Burns Research Group, ANZAC Research Institute, University of Sydney, Concord Hospital, Gate, 3 Hospital road, Concord, NSW 2139, Australia
| | - Ulla Simanainen
- Andrology, ANZAC Research Institute, University of Sydney, Concord Hospital, Gate, 3 Hospital road, Concord, NSW 2139, Australia
| | - Brian Lesmana
- Burns Research Group, ANZAC Research Institute, University of Sydney, Concord Hospital, Gate, 3 Hospital road, Concord, NSW 2139, Australia
| | - Duncan Ma
- Burns Research Group, ANZAC Research Institute, University of Sydney, Concord Hospital, Gate, 3 Hospital road, Concord, NSW 2139, Australia
| | - Jonathan J Hew
- Burns Research Group, ANZAC Research Institute, University of Sydney, Concord Hospital, Gate, 3 Hospital road, Concord, NSW 2139, Australia
| | - Roxanne J Parungao
- Burns Research Group, ANZAC Research Institute, University of Sydney, Concord Hospital, Gate, 3 Hospital road, Concord, NSW 2139, Australia
| | - Zhe Li
- Burns Research Group, ANZAC Research Institute, University of Sydney, Concord Hospital, Gate, 3 Hospital road, Concord, NSW 2139, Australia.,Burns and Reconstructive Surgery Unit, Concord Hospital, Gate, 3 Hospital road, Concord, NSW 2139, Australia
| | - Mark S Cooper
- Adrenal Steroid Laboratory, ANZAC Research Institute, University of Sydney, Concord Hospital, Gate, 3 Hospital road, Concord, NSW 2139, Australia
| | - David J Handelsman
- Andrology, ANZAC Research Institute, University of Sydney, Concord Hospital, Gate, 3 Hospital road, Concord, NSW 2139, Australia
| | - Peter K Maitz
- Burns Research Group, ANZAC Research Institute, University of Sydney, Concord Hospital, Gate, 3 Hospital road, Concord, NSW 2139, Australia.,Burns and Reconstructive Surgery Unit, Concord Hospital, Gate, 3 Hospital road, Concord, NSW 2139, Australia
| | - Yiwei Wang
- Burns Research Group, ANZAC Research Institute, University of Sydney, Concord Hospital, Gate, 3 Hospital road, Concord, NSW 2139, Australia
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Morio H, Reien Y, Hirayama Y, Hashimoto H, Anzai N. Protein kinase C activation upregulates human L-type amino acid transporter 2 function. J Physiol Sci 2021; 71:11. [PMID: 33789576 PMCID: PMC10716992 DOI: 10.1186/s12576-021-00795-0] [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: 10/13/2020] [Accepted: 03/05/2021] [Indexed: 11/10/2022]
Abstract
L-type amino acid transporter 2 (LAT2) is a Na+-independent neutral amino acid transporter, whose function regulation system remains unclarified. Since protein kinase C (PKC) is known to regulate the functions of various transporters, we investigated whether human LAT2 (hLAT2) function is regulated by PKC. In mouse proximal tubule S2 cells, hLAT2 transport activity was upregulated by PKC activation. However, we found that the mRNA and protein expression of hLAT2 was not affected by PKC activation and that the upregulation was independent of the three potential PKC consensus sites in the hLAT2 amino acid sequence. Moreover, we found that PKC activation upregulated the Vmax value for hLAT2-mediated alanine transport, which was not accompanied by the induction of hLAT2 membrane insertion. In conclusion, we showed that hLAT2 function is upregulated by PKC activation, which is not related to either the de novo synthesis, the phosphorylation or the membrane insertion of hLAT2.
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Affiliation(s)
- Hanae Morio
- Department of Pharmacology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuou-ku, Chiba, 260-8670, Japan
| | - Yoshie Reien
- Department of Pharmacology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuou-ku, Chiba, 260-8670, Japan
| | - Yuri Hirayama
- Department of Pharmacology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuou-ku, Chiba, 260-8670, Japan
| | - Hirofumi Hashimoto
- Department of Pharmacology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuou-ku, Chiba, 260-8670, Japan
| | - Naohiko Anzai
- Department of Pharmacology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuou-ku, Chiba, 260-8670, Japan.
- Department of Pharmacology and Toxicology, School of Medicine, Dokkyo Medical University, 880 Kitakobayashi, Mibu-cho, Shimotsuga-gun, Tochigi, 321-0293, Japan.
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5
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Nakai N, Kitai S, Iida N, Inoue S, Nakata K, Murakami T, Higashida K. Induction of Autophagy and Changes in Cellular Metabolism in Glucose Starved C2C12 Myotubes. J Nutr Sci Vitaminol (Tokyo) 2020; 66:41-47. [PMID: 32115452 DOI: 10.3177/jnsv.66.41] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Mouse myoblast C2C12 cells are commonly used as a model system for investigating the metabolic regulation of skeletal muscle. As it is therefore important to understand the metabolic features of C2C12 cells, we examined the effect of glucose starvation on autophagy in C2C12 myotubes. After culture of C2C12 myotubes with high (HG, 25.0 mM) or low (LG, 5.6 mM) glucose concentrations, the concentration of glucose in the LG group had decreased to 0 mM after 24 h of culture and was around 17 mM after 48 h of culture in the HG group. The concentration of lactate increased from 0 to approximately 9 mM at 24 h and then dropped slightly in the LG group, while it increased linearly to 21 mM in the HG group at 48 h. The phosphorylation of p70 S6 kinase, marker for the protein translation initiation was significantly lower and the ratio of LC3-II/LC3-I, marker for the induction of autophagy was significantly higher in the LG group. GLUT1 and hexokinase II expression were significantly higher in the LG group. Together, these changes in glucose and lactate concentrations in the culture media suggest that C2C12 myotubes depend on anaerobic glycolysis. Our findings also suggest that glucose depletion stimulates the expression of key molecules involved in glycolysis and that cellular autophagy is also activated in C2C12 myotubes.
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Affiliation(s)
- Naoya Nakai
- Laboratory of Exercise Nutrition, Department of Nutrition, University of Shiga Prefecture
| | - Saki Kitai
- Laboratory of Exercise Nutrition, Department of Nutrition, University of Shiga Prefecture
| | - Noriko Iida
- Laboratory of Exercise Nutrition, Department of Nutrition, University of Shiga Prefecture
| | - Sachika Inoue
- Laboratory of Exercise Nutrition, Department of Nutrition, University of Shiga Prefecture
| | - Ken Nakata
- Medicine for Sports and Performing Arts, Graduate School of Medicine, Osaka University
| | | | - Kazuhiko Higashida
- Laboratory of Exercise Nutrition, Department of Nutrition, University of Shiga Prefecture
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6
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Inoue S, Mizushima T, Ide H, Jiang G, Goto T, Nagata Y, Netto GJ, Miyamoto H. ATF2 promotes urothelial cancer outgrowth via cooperation with androgen receptor signaling. Endocr Connect 2018; 7:1397-1408. [PMID: 30521479 PMCID: PMC6280600 DOI: 10.1530/ec-18-0364] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 11/09/2018] [Indexed: 11/09/2022]
Abstract
We investigated the functional role of ATF2, a transcription factor normally activated via its phosphorylation in response to phospho-ERK/MAPK signals, in the outgrowth of urothelial cancer. In both neoplastic and non-neoplastic urothelial cells, the expression levels of androgen receptor (AR) correlated with those of phospho-ATF2. Dihydrotestosterone treatment in AR-positive bladder cancer cells also induced the expression of phospho-ATF2 and phospho-ERK as well as nuclear translocation and transcriptional activity of ATF2. Meanwhile, ATF2 knockdown via shRNA resulted in significant decreases in cell viability, migration and invasion of AR-positive bladder cancer lines, but not AR-negative lines, as well as significant increases and decreases in apoptosis or G0/G1 cell cycle phase and S or G2/M phase, respectively. Additionally, the growth of AR-positive tumors expressing ATF2-shRNA in xenograft-bearing mice was retarded, compared with that of control tumors. ATF2 knockdown also resulted in significant inhibition of neoplastic transformation induced by a chemical carcinogen 3-methylcholanthrene, as well as the expression of Bcl-2/cyclin-A2/cyclin-D1/JUN/MMP-2, in immortalized human normal urothelial SVHUC cells stably expressing AR, but not AR-negative SVHUC cells. Finally, immunohistochemistry in surgical specimens demonstrated significant elevation of ATF2/phospho-ATF2/phospho-ERK expression in bladder tumors, compared with non-neoplastic urothelial tissues. Multivariate analysis further showed that moderate/strong ATF2 expression and phospho-ATF2 positivity were independent predictors for recurrence of low-grade tumors (hazard ratio (HR) = 2.956, P = 0.045) and cancer-specific mortality of muscle-invasive tumors (HR = 5.317, P = 0.012), respectively. Thus, ATF2 appears to be activated in urothelial cells through the AR pathway and promotes the development and progression of urothelial cancer.
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Affiliation(s)
- Satoshi Inoue
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, New York, USA
- James P. Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, New York, USA
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Taichi Mizushima
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, New York, USA
- James P. Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, New York, USA
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hiroki Ide
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Guiyang Jiang
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, New York, USA
- James P. Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, New York, USA
| | - Takuro Goto
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, New York, USA
- James P. Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, New York, USA
| | - Yujiro Nagata
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, New York, USA
- James P. Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, New York, USA
| | - George J Netto
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Hiroshi Miyamoto
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, New York, USA
- James P. Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, New York, USA
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Urology, University of Rochester Medical Center, Rochester, New York, USA
- Correspondence should be addressed to H Miyamoto:
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Specific targeting of TGF-β family ligands demonstrates distinct roles in the regulation of muscle mass in health and disease. Proc Natl Acad Sci U S A 2017; 114:E5266-E5275. [PMID: 28607086 DOI: 10.1073/pnas.1620013114] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The transforming growth factor-β (TGF-β) network of ligands and intracellular signaling proteins is a subject of intense interest within the field of skeletal muscle biology. To define the relative contribution of endogenous TGF-β proteins to the negative regulation of muscle mass via their activation of the Smad2/3 signaling axis, we used local injection of adeno-associated viral vectors (AAVs) encoding ligand-specific antagonists into the tibialis anterior (TA) muscles of C57BL/6 mice. Eight weeks after AAV injection, inhibition of activin A and activin B signaling produced moderate (∼20%), but significant, increases in TA mass, indicating that endogenous activins repress muscle growth. Inhibiting myostatin induced a more profound increase in muscle mass (∼45%), demonstrating a more prominent role for this ligand as a negative regulator of adult muscle mass. Remarkably, codelivery of activin and myostatin inhibitors induced a synergistic response, resulting in muscle mass increasing by as much as 150%. Transcription and protein analysis indicated that this substantial hypertrophy was associated with both the complete inhibition of the Smad2/3 pathway and activation of the parallel bone morphogenetic protein (BMP)/Smad1/5 axis (recently identified as a positive regulator of muscle mass). Analyses indicated that hypertrophy was primarily driven by an increase in protein synthesis, but a reduction in ubiquitin-dependent protein degradation pathways was also observed. In models of muscular dystrophy and cancer cachexia, combined inhibition of activins and myostatin increased mass or prevented muscle wasting, respectively, highlighting the potential therapeutic advantages of specifically targeting multiple Smad2/3-activating ligands in skeletal muscle.
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Wendowski O, Redshaw Z, Mutungi G. Dihydrotestosterone treatment rescues the decline in protein synthesis as a result of sarcopenia in isolated mouse skeletal muscle fibres. J Cachexia Sarcopenia Muscle 2017; 8:48-56. [PMID: 27239418 PMCID: PMC4863930 DOI: 10.1002/jcsm.12122] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 01/05/2016] [Accepted: 04/05/2016] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Sarcopenia, the progressive decline in skeletal muscle mass and function with age, is a debilitating condition. It leads to inactivity, falls, and loss of independence. Despite this, its cause(s) and the underlying mechanism(s) are still poorly understood. METHODS In this study, small skeletal muscle fibre bundles isolated from the extensor digitorum longus (a fast-twitch muscle) and the soleus (a slow-twitch muscle) of adult mice of different ages (range 100-900 days old) were used to investigate the effects of ageing and dihydrotestosterone (DHT) treatment on protein synthesis as well as the expression and function of two amino acid transporters; the sodium-coupled neutral amino acid transporter (SNAT) 2, and the sodium-independent L-type amino-acid transporter (LAT) 2. RESULTS At all ages investigated, protein synthesis was always higher in the slow-twitch than in the fast-twitch muscle fibres and decreased with age in both fibre types. However, the decline was greater in the fast-twitch than in the slow-twitch fibres and was accompanied by a reduction in the expression of SNAT2 and LAT2 at the protein level. Again, the decrease in the expression of the amino acid transporters was greater in the fast-twitch than in the slow-twitch fibres. In contrast, ageing had no effect on SNAT2 and LAT2 expressions at the mRNA level. Treating the muscle fibre bundles with physiological concentrations (~2 nM) of DHT for 1 h completely reversed the effects of ageing on protein synthesis and the expression of SNAT2 and LAT2 protein in both fibre types. CONCLUSION From the observations that ageing is accompanied by a reduction in protein synthesis and transporter expression and that these effects are reversed by DHT treatment, we conclude that sarcopenia arises from an age-dependent reduction in protein synthesis caused, in part, by the lack of or by the low bioavailability of the male sex steroid, DHT.
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Affiliation(s)
- Oskar Wendowski
- Department of Medicine, Norwich Medical School University of East Anglia Norwich NR4 7TJ UK
| | - Zoe Redshaw
- Faculty of Health and Life Sciences De Montfort University Leicester UK
| | - Gabriel Mutungi
- Department of Medicine, Norwich Medical School University of East Anglia Norwich NR4 7TJ UK
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The Glutamine Transporters and Their Role in the Glutamate/GABA-Glutamine Cycle. ADVANCES IN NEUROBIOLOGY 2016; 13:223-257. [PMID: 27885631 DOI: 10.1007/978-3-319-45096-4_8] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Glutamine is a key amino acid in the CNS, playing an important role in the glutamate/GABA-glutamine cycle (GGC). In the GGC, glutamine is transferred from astrocytes to neurons, where it will replenish the inhibitory and excitatory neurotransmitter pools. Different transporters participate in this neural communication, i.e., the transporters responsible for glutamine efflux from astrocytes and influx into the neurons, such as the members of the SNAT, LAT, y+LAT, and ASC families of transporters. The SNAT family consists of the transporter isoforms SNAT3 and SNAT5 that are related to efflux from the astrocytic compartment, and SNAT1 and SNAT2 that are associated with glutamine uptake into the neuronal compartment. The isoforms SNAT7 and SNAT8 do not have their role completely understood, but they likely also participate in the GGC. The isoforms LAT2 and y+LAT2 facilitate the exchange of neutral amino acids and cationic amino acids (y+LAT2 isoform) and have been associated with glutamine efflux from astrocytes. ASCT2 is a Na+-dependent antiporter, the participation of which in the GGC also remains to be better characterized. All these isoforms are tightly regulated by transcriptional and translational mechanisms, which are induced by several determinants such as amino acid deprivation, hormones, pH, and the activity of different signaling pathways. Dysfunctional glutamine transporter activity has been associated with the pathophysiological mechanisms of certain neurologic diseases, such as Hepatic Encephalopathy and Manganism. However, there might also be other neuropathological conditions associated with an altered GGC, in which glutamine transporters are dysfunctional. Hence, it appears to be of critical importance that the physiological and pathological aspects of glutamine transporters are thoroughly investigated.
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10
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Yamane S, Nomura R, Yanagihara M, Nakamura H, Fujino H, Matsumoto K, Horie S, Murayama T. L-cysteine/d,L-homocysteine-regulated ileum motility via system L and B°,+ transporter: Modification by inhibitors of hydrogen sulfide synthesis and dietary treatments. Eur J Pharmacol 2015. [DOI: 10.1016/j.ejphar.2015.07.042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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Yao K, Wu J, Zhang J, Bo J, Hong Z, Zu H. Protective Effect of DHT on Apoptosis Induced by U18666A via PI3K/Akt Signaling Pathway in C6 Glial Cell Lines. Cell Mol Neurobiol 2015; 36:801-9. [PMID: 26340949 DOI: 10.1007/s10571-015-0263-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 08/27/2015] [Indexed: 11/27/2022]
Abstract
Various useful animal models, such as Alzheimer's disease and Niemann-Pick disease, were provided by U18666A. However, the pathogenesis of U18666A-induced diseases, including U18666A-mediated apoptosis, remains incompletely elucidated, and therapeutic strategies are still limited. Dihydrotestosterone (DHT) has been reported to contribute to the prevention and treatment of neurodegenerative disorders. Our study investigated the neuroprotective activity of DHT in U18666A-related diseases. Apoptosis of C6 cells was detected by Hoechst 33258 fluorescent staining and flow cytometry with annexin V-FITC/PI dual staining. Cell viability was assessed using Cell Counting Kit-8. Expression of apoptosis-related proteins, such as Akt, seladin-1, Bcl-2 family proteins, and caspase-3, was determined using Western blot. Our results demonstrated that the apoptotic rate of C6 cells significantly increased after U18666A addition, but was remarkably reduced after DHT treatment. Pretreatment with DHT attenuated U18666A-induced cell viability loss. PI3K inhibitor LY294002 could suppress DHT anti-apoptotic effect. Furthermore, we discovered that U18666A could significantly downregulate seladin-1 expression in a dose-dependent manner, but no significant change was observed in Bcl-xL, Bax, and P-Akt protein expressions. Compared with U18666A-treated group, the expression of P-Akt, seladin-1, and Bcl-xL significantly increased, and the expression of Bax and caspase-3 remarkably reduced after DHT treatment. However, in the presence of LY294002, the effect of DHT was reversed. In conclusion, we found that seladin-1 may take part in U18666A-induced apoptosis. DHT may inhibit U18666A-induced apoptosis by regulating downstream apoptosis-related proteins including seladin-1, caspase-3, Bcl-xL, and Bax through activation of the PI3K/Akt signal pathway.
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Affiliation(s)
- Kai Yao
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No. 1508 Longhang Road, Jinshan District, Shanghai, 201508, China
| | - Junfeng Wu
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No. 1508 Longhang Road, Jinshan District, Shanghai, 201508, China
| | - Jianfeng Zhang
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No. 1508 Longhang Road, Jinshan District, Shanghai, 201508, China
| | - Jimei Bo
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No. 1508 Longhang Road, Jinshan District, Shanghai, 201508, China
| | - Zhen Hong
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No. 1508 Longhang Road, Jinshan District, Shanghai, 201508, China
| | - Hengbing Zu
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No. 1508 Longhang Road, Jinshan District, Shanghai, 201508, China.
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12
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Boncompagni S, Arthurton L, Akujuru E, Pearson T, Steverding D, Protasi F, Mutungi G. Membrane glucocorticoid receptors are localised in the extracellular matrix and signal through the MAPK pathway in mammalian skeletal muscle fibres. J Physiol 2015; 593:2679-92. [PMID: 25846902 DOI: 10.1113/jp270502] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/30/2015] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Many studies have previously suggested the existence of stress hormone receptors on the cell membrane of many cell types, including skeletal muscle fibres; however, the exact localisation of these receptors and how they signal to the rest of the cell is poorly understood. In this study, we investigated the localisation and the mechanism(s) underlying the physiological functions of these receptors in mouse skeletal muscle cells. We found that the receptors were present throughout muscle development and that, in adult muscle fibres, they were localised in the extracellular matrix, satellite cells (muscle stem cells) and close to mitochondria. We also found that they signalled to the rest of the cell by activating enzymes called mitogen-activated protein kinases. From these results we suggest that, at physiological concentrations, stress hormones may be important in skeletal muscle differentiation, repair and regeneration. ABSTRACT A number of studies have previously proposed the existence of glucocorticoid receptors on the plasma membrane of many cell types, including skeletal muscle fibres. However, their exact localisation and the cellular signalling pathway(s) they utilise to communicate with the rest of the cell are still poorly understood. In this study, we investigated the localisation and the mechanism(s) underlying the non-genomic physiological functions of these receptors in mouse skeletal muscle cells. The results show that the receptors were localised in the cytoplasm in myoblasts, in the nucleus in myotubes, in the extracellular matrix, in satellite cells and in the proximity of mitochondria in adult muscle fibres. Also, they bound laminin in a glucocorticoid-dependent manner. Treating small skeletal muscle fibre bundles with the synthetic glucocorticoid beclomethasone dipropionate increased the phosphorylation (= activation) of extracellular signal-regulated kinases 1 and 2, c-Jun N-terminal kinase and p38 mitogen-activated protein kinase. This occurred within 5 min and depended on the fibre type and the duration of the treatment. It was also abolished by the glucocorticoid receptor inhibitor, mifepristone, and a monoclonal antibody against the receptor. From these results we conclude that the non-genomic/non-canonical physiological functions of glucocorticoids, in adult skeletal muscle fibres, are mediated by a glucocorticoid receptor localised in the extracellular matrix, in satellite cells and close to mitochondria, and involve activation of the mitogen-activated protein kinase pathway.
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Affiliation(s)
- Simona Boncompagni
- Centre for Research on Aging, University G. d'Annunzio, I-66013, Chieti, Italy
| | - Lewis Arthurton
- School of Life Sciences, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Eugene Akujuru
- Department of Medicine, Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Timothy Pearson
- Department of Medicine, Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Dietmar Steverding
- Department of Medicine, Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Feliciano Protasi
- Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, I-66013, Chieti, Italy
| | - Gabriel Mutungi
- Department of Medicine, Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, UK
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Walker WH, Easton E, Moreci RS, Toocheck C, Anamthathmakula P, Jeyasuria P. Restoration of spermatogenesis and male fertility using an androgen receptor transgene. PLoS One 2015; 10:e0120783. [PMID: 25803277 PMCID: PMC4372537 DOI: 10.1371/journal.pone.0120783] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 01/27/2015] [Indexed: 01/25/2023] Open
Abstract
Androgens signal through the androgen receptor (AR) to regulate male secondary sexual characteristics, reproductive tract development, prostate function, sperm production, bone and muscle mass as well as body hair growth among other functions. We developed a transgenic mouse model in which endogenous AR expression was replaced by a functionally modified AR transgene. A bacterial artificial chromosome (BAC) was constructed containing all AR exons and introns plus 40 kb each of 5' and 3' regulatory sequence. Insertion of an internal ribosome entry site and the EGFP gene 3’ to AR allowed co-expression of AR and EGFP. Pronuclear injection of the BAC resulted in six founder mice that displayed EGFP production in appropriate AR expressing tissues. The six founder mice were mated into a Sertoli cell specific AR knockout (SCARKO) background in which spermatogenesis is blocked at the meiosis stage of germ cell development. The AR-EGFP transgene was expressed in a cyclical manner similar to that of endogenous AR in Sertoli cells and fertility was restored as offspring were produced in the absence of Sertoli cell AR. Thus, the AR-EGFP transgene under the control of AR regulatory elements is capable of rescuing AR function in a cell selective, AR-null background. These initial studies provide proof of principle that a strategy employing the AR-EGFP transgene can be used to understand AR functions. Transgenic mice expressing selective modifications of the AR-EGFP transgene may provide crucial information needed to elicit the molecular mechanisms by which AR acts in the testis and other androgen responsive tissues.
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Affiliation(s)
- William H. Walker
- Center for Research in Reproductive Physiology, Department of Obstetrics, Gynecology and Reproductive Sciences, Magee Women’s Research Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
| | - Evan Easton
- Center for Research in Reproductive Physiology, Department of Obstetrics, Gynecology and Reproductive Sciences, Magee Women’s Research Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Rebecca S. Moreci
- Center for Research in Reproductive Physiology, Department of Obstetrics, Gynecology and Reproductive Sciences, Magee Women’s Research Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Corey Toocheck
- Center for Research in Reproductive Physiology, Department of Obstetrics, Gynecology and Reproductive Sciences, Magee Women’s Research Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Prashanth Anamthathmakula
- Center for Research in Reproductive Physiology, Department of Obstetrics, Gynecology and Reproductive Sciences, Magee Women’s Research Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Pancharatnam Jeyasuria
- Center for Research in Reproductive Physiology, Department of Obstetrics, Gynecology and Reproductive Sciences, Magee Women’s Research Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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14
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Wang Q, Holst J. L-type amino acid transport and cancer: targeting the mTORC1 pathway to inhibit neoplasia. Am J Cancer Res 2015; 5:1281-1294. [PMID: 26101697 PMCID: PMC4473310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 03/12/2015] [Indexed: 06/04/2023] Open
Abstract
The L-type amino acid transporter (LAT) family are Na(+)-independent transporters, which deliver neutral amino acids into cells. The four LATs, LAT1 (SLC7A5), LAT2 (SLC7A8), LAT3 (SLC43A1) and LAT4 (SLC43A2), are responsible for the majority of cellular leucine uptake. They show increased expression in many cancers, and are critical for control of protein translation and cell growth through the mTORC1 pathway. The increased transporter expression observed in cancers is regulated by transcriptional pathways such as hormone receptors, c-myc and nutrient starvation responses. We review the expression and function of the LAT family in cancer, as well as the recent development of specific inhibitors targeting LAT1 or LAT3. These LAT family inhibitors may be useful adjuvant therapeutics in multiple cancers.
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Affiliation(s)
- Qian Wang
- Origins of Cancer Program, Centenary InstituteCamperdown, Australia
- Sydney Medical School, University of SydneyAustralia
| | - Jeff Holst
- Origins of Cancer Program, Centenary InstituteCamperdown, Australia
- Sydney Medical School, University of SydneyAustralia
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15
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Ferry A, Schuh M, Parlakian A, Mgrditchian T, Valnaud N, Joanne P, Butler-Browne G, Agbulut O, Metzger D. Myofiber androgen receptor promotes maximal mechanical overload-induced muscle hypertrophy and fiber type transition in male mice. Endocrinology 2014; 155:4739-48. [PMID: 25216388 DOI: 10.1210/en.2014-1195] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The first aim of this study was to examine the role of myofiber androgen receptor (AR) in male mice on muscle performance gain and remodeling-induced muscle mechanical overloading (OVL) that mimics resistance training. The response of OVL in mice in which AR is selectively ablated in myofibers (AR(skm-/y)) was compared with that of wild-type (WT) mice. In addition, we determined whether the synthetic anabolic androgen nandrolone administration affects the OVL response. We found that OVL increased absolute maximal force and fatigue resistance in both mouse genotypes (P < .05). However, the absolute maximal force increased more in AR(skm-/y) mice as compared with WT mice (+88% vs +63%) (P < .05). Muscle weight increased less in response to OVL in AR(skm-/y) mice (+54%) than in WT mice (+115%) (P < .05). The fiber number per cross-section similarly increased in both mouse genotypes after OVL (P < .05). In contrast to WT mice, the diameter of the fibers expressing myosin heavy chain (MHC)-2x decreased after OVL in AR(skm-/y) mice (P < .05). The MHC-2b to MHC-2a fiber type transition in response to OVL was reduced in AR(skm-/y) mice as compared with WT mice (P < .05). Finally, nandrolone administration during OVL did not further improve absolute maximal force and fatigue resistance and markedly alter muscle remodeling in both mouse genotypes. Together, our results indicate that myofiber AR is required for a complete response to OVL and that exogenous androgens do not increase muscle performance during intensive remodeling in male mice.
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Affiliation(s)
- Arnaud Ferry
- Université Pierre et Marie Curie Université Paris 06 (A.F., T.M., N.V., G.B.-B.), Sorbonne Universités, Inserm Unité 974, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7215, Institut de Myologie, F-75013 Paris, France; Université Paris Descartes (A.F.), Sorbonne Paris Cité, F-75006 Paris, France; Institut de Génétique et de Biologie Moléculaire et Cellulaire (M.S., D.M.), Centre National de la Recherche Scientifique Unité Mixte de Recherche 7104, Inserm Unité 964, Université de Strasbourg, Illkirch 67404, France; and Université Pierre et Marie Curie Université Paris 06 (A.P., T.M., P.J., O.A.), Sorbonne Universités, Unité Mixte de Recherche Centre National de la Recherche Scientifique 8256, Biological Adaptation and Ageing, F-75005 Paris, France
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16
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Pochini L, Scalise M, Galluccio M, Indiveri C. Membrane transporters for the special amino acid glutamine: structure/function relationships and relevance to human health. Front Chem 2014; 2:61. [PMID: 25157349 PMCID: PMC4127817 DOI: 10.3389/fchem.2014.00061] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 07/16/2014] [Indexed: 12/26/2022] Open
Abstract
Glutamine together with glucose is essential for body's homeostasis. It is the most abundant amino acid and is involved in many biosynthetic, regulatory and energy production processes. Several membrane transporters which differ in transport modes, ensure glutamine homeostasis by coordinating its absorption, reabsorption and delivery to tissues. These transporters belong to different protein families, are redundant and ubiquitous. Their classification, originally based on functional properties, has recently been associated with the SLC nomenclature. Function of glutamine transporters is studied in cells over-expressing the transporters or, more recently in proteoliposomes harboring the proteins extracted from animal tissues or over-expressed in microorganisms. The role of the glutamine transporters is linked to their transport modes and coupling with Na+ and H+. Most transporters share specificity for other neutral or cationic amino acids. Na+-dependent co-transporters efficiently accumulate glutamine while antiporters regulate the pools of glutamine and other amino acids. The most acknowledged glutamine transporters belong to the SLC1, 6, 7, and 38 families. The members involved in the homeostasis are the co-transporters B0AT1 and the SNAT members 1, 2, 3, 5, and 7; the antiporters ASCT2, LAT1 and 2. The last two are associated to the ancillary CD98 protein. Some information on regulation of the glutamine transporters exist, which, however, need to be deepened. No information at all is available on structures, besides some homology models obtained using similar bacterial transporters as templates. Some models of rat and human glutamine transporters highlight very similar structures between the orthologs. Moreover the presence of glycosylation and/or phosphorylation sites located at the extracellular or intracellular faces has been predicted. ASCT2 and LAT1 are over-expressed in several cancers, thus representing potential targets for pharmacological intervention.
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Affiliation(s)
- Lorena Pochini
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria Arcavacata di Rende, Italy
| | - Mariafrancesca Scalise
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria Arcavacata di Rende, Italy
| | - Michele Galluccio
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria Arcavacata di Rende, Italy
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria Arcavacata di Rende, Italy
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17
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Whey protein intake after resistance exercise activates mTOR signaling in a dose-dependent manner in human skeletal muscle. Eur J Appl Physiol 2014; 114:735-42. [PMID: 24384983 DOI: 10.1007/s00421-013-2812-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 12/21/2013] [Indexed: 01/03/2023]
Abstract
PURPOSE Protein ingestion after resistance exercise increases muscle protein synthesis (MPS) in a dose-dependent manner. However, the molecular mechanism(s) for the dose-dependency of MPS remains unclear. This study aimed to determine the dose response of mammalian target of rapamycin (mTOR) signaling in muscle with ingestion of protein after resistance exercise. METHODS Fifteen male subjects performed four sets of six unilateral isokinetic concentric knee extensions. Immediately after exercise, eight subjects consumed water only. The other seven subjects, in a randomized-order crossover design, took either a 10 [3.6 g essential amino acids (EAA)] or 20 g (7.1 g EAA) solution of whey protein. Muscle biopsies from the vastus lateralis muscle were taken 30 min before and 1 h after resistance exercise. Phosphorylation of Akt (Ser473), mTOR (Ser2448), 4E-BP1 (Thr37/46), and S6K1 (Thr389) was measured by western blotting. RESULTS Concentric knee extension exercise alone did not increase phosphorylation of Akt and mTOR 1 h after exercise, but ingesting protein after exercise significantly increased the phosphorylation of Akt and mTOR in a dose-dependent manner (P < 0.05). 4E-BP1 phosphorylation significantly decreased after resistance exercise (P < 0.05), but subjects who took 10 or 20 g of protein after exercise showed increased 4E-BP1 from post-exercise dephosphorylation (P < 0.05). S6K1 phosphorylation significantly increased after resistance exercise (P < 0.05), and 20 g of protein further increased S6K1 phosphorylation compared with ingestion of 10 g (P < 0.05). CONCLUSIONS These findings suggest that whey protein intake after resistance exercise activates mTOR signaling in a dose-dependent manner in untrained men.
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18
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Aye ILMH, Jansson T, Powell TL. Interleukin-1β inhibits insulin signaling and prevents insulin-stimulated system A amino acid transport in primary human trophoblasts. Mol Cell Endocrinol 2013; 381:46-55. [PMID: 23891856 PMCID: PMC3795822 DOI: 10.1016/j.mce.2013.07.013] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 06/13/2013] [Accepted: 07/15/2013] [Indexed: 02/08/2023]
Abstract
Interleukin-1β (IL-1β) promotes insulin resistance in tissues such as liver and skeletal muscle; however the influence of IL-1β on placental insulin signaling is unknown. We recently reported increased IL-1β protein expression in placentas of obese mothers, which could contribute to insulin resistance. In this study, we tested the hypothesis that IL-1β inhibits insulin signaling and prevents insulin-stimulated amino acid transport in cultured primary human trophoblast (PHT) cells. Cultured trophoblasts isolated from term placentas were treated with physiological concentrations of IL-1β (10pg/ml) for 24h. IL-1β increased the phosphorylation of insulin receptor substrate-1 (IRS-1) at Ser307 (inhibitory) and decreased total IRS-1 protein abundance but did not affect insulin receptor β expression. Furthermore, IL-1β inhibited insulin-stimulated phosphorylation of IRS-1 (Tyr612, activation site) and Akt (Thr308) and prevented insulin-stimulated increase in PI3K/p85 and Grb2 protein expression. IL-1β alone stimulated cRaf (Ser338), MEK (Ser221) and Erk1/2 (Thr202/Tyr204) phosphorylation. The inflammatory pathways nuclear factor kappa B and c-Jun N-terminal kinase, which are involved in insulin resistance, were also activated by IL-1β treatment. Moreover, IL-1β inhibited insulin-stimulated System A, but not System L amino acid uptake, indicating functional impairment of insulin signaling. In conclusion, IL-1β inhibited the insulin signaling pathway by inhibiting IRS-1 signaling and prevented insulin-stimulated System A transport, thereby promoting insulin resistance in cultured PHT cells. These findings indicate that conditions which lead to increased systemic maternal or placental IL-1β levels may attenuate the effects of maternal insulin on placental function and consequently fetal growth.
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Affiliation(s)
- Irving L M H Aye
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
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Pérez MHA, Cormack J, Mallinson D, Mutungi G. A membrane glucocorticoid receptor mediates the rapid/non-genomic actions of glucocorticoids in mammalian skeletal muscle fibres. J Physiol 2013; 591:5171-85. [PMID: 23878367 PMCID: PMC3810817 DOI: 10.1113/jphysiol.2013.256586] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Accepted: 07/19/2013] [Indexed: 12/11/2022] Open
Abstract
Glucocorticoids (GCs) are steroid hormones released from the adrenal gland in response to stress. They are also some of the most potent anti-inflammatory and immunosuppressive drugs currently in clinical use. They exert most of their physiological and pharmacological actions through the classical/genomic pathway. However, they also have rapid/non-genomic actions whose physiological and pharmacological functions are still poorly understood. Therefore, the primary aim of this study was to investigate the rapid/non-genomic effects of two widely prescribed glucocorticoids, beclomethasone dipropionate (BDP) and prednisolone acetate (PDNA), on force production in isolated, intact, mouse skeletal muscle fibre bundles. The results show that the effects of both GCs on maximum isometric force (Po) were fibre-type dependent. Thus, they increased Po in the slow-twitch fibre bundles without significantly affecting that of the fast-twitch fibre bundles. The increase in Po occurred within 10 min and was insensitive to the transcriptional inhibitor actinomycin D. Also, it was maximal at ∼250 nM and was blocked by the glucocorticoid receptor (GCR) inhibitor RU486 and a monoclonal anti-GCR, suggesting that it was mediated by a membrane (m) GCR. Both muscle fibre types expressed a cytosolic GCR. However, a mGCR was present only in the slow-twitch fibres. The receptor was more abundant in oxidative than in glycolytic fibres and was confined mainly to the periphery of the fibres where it co-localised with laminin. From these findings we conclude that the rapid/non-genomic actions of GCs are mediated by a mGCR and that they are physiologically/therapeutically beneficial, especially in slow-twitch muscle fibres.
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20
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Ma Y, Liang D, Liu J, Wen JG, Servoll E, Waaler G, Sæter T, Axcrona K, Vlatkovic L, Axcrona U, Paus E, Yang Y, Zhang Z, Kvalheim G, Nesland JM, Suo Z. SHBG is an important factor in stemness induction of cells by DHT in vitro and associated with poor clinical features of prostate carcinomas. PLoS One 2013; 8:e70558. [PMID: 23936228 PMCID: PMC3728318 DOI: 10.1371/journal.pone.0070558] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Accepted: 06/24/2013] [Indexed: 11/18/2022] Open
Abstract
Androgen plays a vital role in prostate cancer development. However, it is not clear whether androgens influence stem-like properties of prostate cancer, a feature important for prostate cancer progression. In this study, we show that upon DHT treatment in vitro, prostate cancer cell lines LNCaP and PC-3 were revealed with higher clonogenic potential and higher expression levels of stemness related factors CD44, CD90, Oct3/4 and Nanog. Moreover, sex hormone binding globulin (SHBG) was also simultaneously upregulated in these cells. When the SHBG gene was blocked by SHBG siRNA knock-down, the induction of Oct3/4, Nanog, CD44 and CD90 by DHT was also correspondingly blocked in these cells. Immunohistochemical evaluation of clinical samples disclosed weakly positive, and areas negative for SHBG expression in the benign prostate tissues, while most of the prostate carcinomas were strongly positive for SHBG. In addition, higher levels of SHBG expression were significantly associated with higher Gleason score, more seminal vesicle invasions and lymph node metastases. Collectively, our results show a role of SHBG in upregulating stemness of prostate cancer cells upon DHT exposure in vitro, and SHBG expression in prostate cancer samples is significantly associated with poor clinicopathological features, indicating a role of SHBG in prostate cancer progression.
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Affiliation(s)
- Yuanyuan Ma
- Department of Pathology, The Norwegian Radium Hospital, Institute of Clinical Medicine, Oslo University Hospital, Faculty of Medicine, University of Oslo, Oslo, Norway
- Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Thoracic Surgery II, Peking University Cancer Hospital & Institute, Beijing, China
| | - Dongming Liang
- Department of Pathology, The Norwegian Radium Hospital, Institute of Clinical Medicine, Oslo University Hospital, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Jian Liu
- Department of Pathology, The Norwegian Radium Hospital, Institute of Clinical Medicine, Oslo University Hospital, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Jian-Guo Wen
- Department of Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Henan, China
| | - Einar Servoll
- Department of Surgery, Soerlandet Hospital, Arendal, Norway
| | - Gudmund Waaler
- Department of Surgery, Soerlandet Hospital, Arendal, Norway
| | | | - Karol Axcrona
- Departments of Urology, The Norwegian Radium Hospital, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Ljiljana Vlatkovic
- Department of Pathology, The Norwegian Radium Hospital, Institute of Clinical Medicine, Oslo University Hospital, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Ulrika Axcrona
- Department of Pathology, The Norwegian Radium Hospital, Institute of Clinical Medicine, Oslo University Hospital, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Elisabeth Paus
- Department of Medical Biochemistry, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Yue Yang
- Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Thoracic Surgery II, Peking University Cancer Hospital & Institute, Beijing, China
| | - Zhiqian Zhang
- Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Cell Biology, Peking University Cancer Hospital & Institute, Beijing, China
| | - Gunnar Kvalheim
- Departments of Cell Therapy, The Norwegian Radium Hospital, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Jahn M. Nesland
- Department of Pathology, The Norwegian Radium Hospital, Institute of Clinical Medicine, Oslo University Hospital, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Zhenhe Suo
- Department of Pathology, The Norwegian Radium Hospital, Institute of Clinical Medicine, Oslo University Hospital, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Henan, China
- * E-mail:
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Smith AA, Toone R, Peacock O, Drawer S, Stokes KA, Cook CJ. Dihydrotestosterone is elevated following sprint exercise in healthy young men. J Appl Physiol (1985) 2013; 114:1435-40. [DOI: 10.1152/japplphysiol.01419.2012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Dihydrotestosterone (DHT) exerts both functional and signaling effects extending beyond the effects of testosterone in rodent skeletal muscle. As a primer for investigating the role of DHT in human skeletal muscle function, this study aimed to determine whether circulating DHT is acutely elevated in men following a bout of repeat sprint exercise and to establish the importance of training status and sprint performance to this response. Fourteen healthy active young men (V̇o2max61.0 ± 8.1 ml·kg body mass−1·min−1) performed a bout of repeat sprint cycle exercise at a target workload based on an incremental work-rate maximum (10 × 30 s at 150% Wmaxwith 90-s recovery). Venous blood samples were collected preexercise and 5 and 60 min after exercise. Five minutes after exercise, there were significant elevations in total testosterone (TT; P < 0.001), free testosterone (FT; P < 0.001), and DHT ( P = 0.004), which returned to baseline after 1 h. Changes in DHT with exercise (5 min postexercise − preexercise) correlated significantly with changes in TT ( r = 0.870; P < 0.001) and FT ( r = 0.914; P < 0.001). Sprinting cadence correlated with changes in FT ( r = 0.697; P = 0.006), DHT ( r = 0.625; P = 0.017), and TT ( r = 0.603; P = 0.022), and habitual training volume correlated with the change in TT ( r = 0.569, P = 0.034). In conclusion, our data demonstrate that DHT is acutely elevated following sprint cycle exercise and that this response is influenced by cycling cadence. The importance of DHT in the context of exercise training and sports performance remains to be determined.
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Affiliation(s)
- Alan A. Smith
- Sport, Health and Exercise Science, Department for Health, University of Bath
- United Kingdom Sports Council, London, United Kingdom
| | - Rebecca Toone
- Sport, Health and Exercise Science, Department for Health, University of Bath
| | - Oliver Peacock
- Sport, Health and Exercise Science, Department for Health, University of Bath
| | - Scott Drawer
- United Kingdom Sports Council, London, United Kingdom
| | - Keith A. Stokes
- Sport, Health and Exercise Science, Department for Health, University of Bath
| | - Christian J. Cook
- Sport, Health and Exercise Science, Department for Health, University of Bath
- United Kingdom Sports Council, London, United Kingdom
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22
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Overcash RF, Chappell VA, Green T, Geyer CB, Asch AS, Ruiz-Echevarría MJ. Androgen signaling promotes translation of TMEFF2 in prostate cancer cells via phosphorylation of the α subunit of the translation initiation factor 2. PLoS One 2013; 8:e55257. [PMID: 23405127 PMCID: PMC3566213 DOI: 10.1371/journal.pone.0055257] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 12/27/2012] [Indexed: 01/21/2023] Open
Abstract
The type I transmembrane protein with epidermal growth factor and two follistatin motifs 2 (TMEFF2), is expressed mainly in brain and prostate. Expression of TMEFF2 is deregulated in prostate cancer, suggesting a role in this disease, but the molecular mechanism(s) involved in this effect are not clear. Although androgens promote tmeff2 transcription, androgen delivery to castrated animals carrying CWR22 xenografts increases TMEFF2 protein levels in the absence of mRNA changes, suggesting that TMEFF2 may also be post-transcriptionally regulated. Here we show that translation of TMEFF2 is regulated by androgens. Addition of physiological concentrations of dihydrotestosterone (DHT) to prostate cancer cell lines increases translation of endogenous TMEFF2 or transfected TMEFF2-Luciferase fusions, and this effect requires the presence of upstream open reading frames (uORFs) in the 5′-untranslated region (5′-UTR) of TMEFF2. Using chemical and siRNA inhibition of the androgen receptor (AR), we show that the androgen effect on TMEFF2 translation is mediated by the AR. Importantly, DHT also promotes phosphorylation of the α subunit of the translation initiation factor 2 (eIF2α) in an AR-dependent manner, paralleling the effect on TMEFF2 translation. Moreover, endoplasmic reticulum (ER) stress conditions, which promote eIF2α phosphorylation, also stimulate TMEFF2 translation. These results indicate that androgen signaling promotes eIF2α phosphorylation and subsequent translation of TMEFF2 via a mechanism that requires uORFs in the 5′-UTR of TMEFF2.
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Affiliation(s)
- Ryan F. Overcash
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, North Carolina, United States of America
| | - Vesna A. Chappell
- Department of Anatomy and Cell Biology, Brody School of Medicine at East Carolina University, Greenville, North Carolina, United States of America
| | - Thomas Green
- Department of Internal Medicine, Division of Hematology/Oncology. Brody School of Medicine at East Carolina University, Greenville, North Carolina, United States of America
| | - Christopher B. Geyer
- Department of Anatomy and Cell Biology, Brody School of Medicine at East Carolina University, Greenville, North Carolina, United States of America
| | - Adam S. Asch
- Department of Internal Medicine, Division of Hematology/Oncology. Brody School of Medicine at East Carolina University, Greenville, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Maria J. Ruiz-Echevarría
- Department of Anatomy and Cell Biology, Brody School of Medicine at East Carolina University, Greenville, North Carolina, United States of America
- Department of Internal Medicine, Division of Hematology/Oncology. Brody School of Medicine at East Carolina University, Greenville, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
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23
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Borzykh AA, Kuzmin IV, Mart’ianov AA, Borovik AS, Sharova AP, Tarasova OS, Vinogradova OL. Changes of rat respiratory and locomotory muscles during aerobic exercise training in continuous and interval regimens. Biophysics (Nagoya-shi) 2012. [DOI: 10.1134/s0006350912050053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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24
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Melnik B. Dietary intervention in acne: Attenuation of increased mTORC1 signaling promoted by Western diet. DERMATO-ENDOCRINOLOGY 2012; 4:20-32. [PMID: 22870349 PMCID: PMC3408989 DOI: 10.4161/derm.19828] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The purpose of this paper is to highlight the endocrine signaling of Western diet, a fundamental environmental factor involved in the pathogenesis of epidemic acne. Western nutrition is characterized by high calorie uptake, high glycemic load, high fat and meat intake, as well as increased consumption of insulin- and IGF-1-level elevating dairy proteins. Metabolic signals of Western diet are sensed by the nutrient-sensitive kinase, mammalian target of rapamycin complex 1 (mTORC1), which integrates signals of cellular energy, growth factors (insulin, IGF-1) and protein-derived signals, predominantly leucine, provided in high amounts by milk proteins and meat. mTORC1 activates SREBP, the master transcription factor of lipogenesis. Leucine stimulates mTORC1-SREBP signaling and leucine is directly converted by sebocytes into fatty acids and sterols for sebaceous lipid synthesis. Over-activated mTORC1 increases androgen hormone secretion and most likely amplifies androgen-driven mTORC1 signaling of sebaceous follicles. Testosterone directly activates mTORC1. Future research should investigate the effects of isotretinoin on sebocyte mTORC1 activity. It is conceivable that isotretinoin may downregulate mTORC1 in sebocytes by upregulation of nuclear levels of FoxO1. The role of Western diet in acne can only be fully appreciated when all stimulatory inputs for maximal mTORC1 activation, i.e., glucose, insulin, IGF-1 and leucine, are adequately considered. Epidemic acne has to be recognized as an mTORC1-driven disease of civilization like obesity, type 2 diabetes, cancer and neurodegenerative diseases. These new insights into Western diet-mediated mTORC1-hyperactivity provide a rational basis for dietary intervention in acne by attenuating mTORC1 signaling by reducing (1) total energy intake, (2) hyperglycemic carbohydrates, (3) insulinotropic dairy proteins and (4) leucine-rich meat and dairy proteins. The necessary dietary changes are opposed to the evolution of industrialized food and fast food distribution of Westernized countries. An attenuation of mTORC1 signaling is only possible by increasing the consumption of vegetables and fruit, the major components of vegan or Paleolithic diets. The dermatologist bears a tremendous responsibility for his young acne patients who should be advised to modify their dietary habits in order to reduce activating stimuli of mTORC1, not only to improve acne but to prevent the harmful and expensive march to other mTORC1-related chronic diseases later in life.
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Affiliation(s)
- Bodo Melnik
- Department of Dermatology; Environmental Medicine and Health Theory; University of Osnabrück; Osnabrück, Germany
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25
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Abundance of amino acid transporters involved in mTORC1 activation in skeletal muscle of neonatal pigs is developmentally regulated. Amino Acids 2012; 45:523-30. [PMID: 22643846 DOI: 10.1007/s00726-012-1326-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 05/15/2012] [Indexed: 01/22/2023]
Abstract
Previously we demonstrated that the insulin- and amino acid-induced activation of the mammalian target of rapamycin complex 1 (mTORC1) is developmentally regulated in neonatal pigs. Recent studies have indicated that members of the System A transporter (SNAT2), the System N transporter (SNAT3), the System L transporters (LAT1 and LAT2), and the proton-assisted amino acid transporters (PAT1 and PAT2) have crucial roles in the activation of mTORC1 and that the abundance of amino acid transporters is positively correlated with their activation. This study aimed to determine the effect of the post-prandial rise in insulin and amino acids on the abundance or activation of SNAT2, SNAT3, LAT1, LAT2, PAT1, and PAT2 and whether the response is modified by development. Overnight fasted 6- and 26-day-old pigs were infused for 2 h with saline (Control) or with insulin or amino acids to achieve fed levels while amino acids or insulin, respectively, as well as glucose were maintained at fasting levels. The abundance of SNAT2, SNAT3, LAT1, LAT2, PAT1, and PAT2 was higher in muscle of 6- compared with 26-day-old pigs. The abundance of the PAT2-mTOR complex was greater in 6- than in 26-day-old pigs, consistent with the higher activation of mTORC1. Neither insulin nor amino acids altered amino acid transporter or PAT2-mTOR complex abundance. In conclusion, the amino acid transporters, SNAT 2/3, LAT 1/2, and PAT1/2, likely have important roles in the enhanced amino acid-induced activation of mTORC1 in skeletal muscle of the neonate.
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26
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Batista TM, Alonso-Magdalena P, Vieira E, Amaral MEC, Cederroth CR, Nef S, Quesada I, Carneiro EM, Nadal A. Short-term treatment with bisphenol-A leads to metabolic abnormalities in adult male mice. PLoS One 2012; 7:e33814. [PMID: 22470480 PMCID: PMC3314682 DOI: 10.1371/journal.pone.0033814] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 02/17/2012] [Indexed: 01/11/2023] Open
Abstract
Bisphenol-A (BPA) is one of the most widespread endocrine disrupting chemicals (EDC) used as the base compound in the manufacture of polycarbonate plastics. Although evidence points to consider exposure to BPA as a risk factor for insulin resistance, its actions on whole body metabolism and on insulin-sensitive tissues are still unclear. The aim of the present work was to study the effects of low doses of BPA in insulin-sensitive peripheral tissues and whole body metabolism in adult mice. Adult mice were treated with subcutaneous injection of 100 µg/kg BPA or vehicle for 8 days. Whole body energy homeostasis was assessed with in vivo indirect calorimetry. Insulin signaling assays were conducted by western blot analysis. Mice treated with BPA were insulin resistant and had increased glucose-stimulated insulin release. BPA-treated mice had decreased food intake, lower body temperature and locomotor activity compared to control. In skeletal muscle, insulin-stimulated tyrosine phosphorylation of the insulin receptor β subunit was impaired in BPA-treated mice. This impairment was associated with a reduced insulin-stimulated Akt phosphorylation in the Thr(308) residue. Both skeletal muscle and liver displayed an upregulation of IRS-1 protein by BPA. The mitogen-activated protein kinase (MAPK) signaling pathway was also impaired in the skeletal muscle from BPA-treated mice. In the liver, BPA effects were of lesser intensity with decreased insulin-stimulated tyrosine phosphorylation of the insulin receptor β subunit.In conclusion, short-term treatment with low doses of BPA slows down whole body energy metabolism and disrupts insulin signaling in peripheral tissues. Thus, our findings support the notion that BPA can be considered a risk factor for the development of type 2 diabetes.
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Affiliation(s)
- Thiago M. Batista
- Departamento de Anatomia, Biologia Celular, Fisiologia e Biofísica, Instituto de Biologia, Universidade Estadual de Campinas, UNICAMP, Campinas, Sao Paulo, Brazil
- Instituto Nacional de Ciência e Tecnologia de Obesidade e Diabetes, Sao Paulo, Brazil
| | - Paloma Alonso-Magdalena
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, CIBERDEM, Elche, Spain
| | - Elaine Vieira
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, CIBERDEM, Elche, Spain
| | - Maria Esmeria C. Amaral
- Centro Universitário Hermínio Ometto, Programa de Pós Graduação em Ciências Biomédicas - UNIARARAS, Araras, Sao Paulo, Brazil
| | - Christopher R. Cederroth
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland
| | - Serge Nef
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland
| | - Ivan Quesada
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, CIBERDEM, Elche, Spain
| | - Everardo M. Carneiro
- Departamento de Anatomia, Biologia Celular, Fisiologia e Biofísica, Instituto de Biologia, Universidade Estadual de Campinas, UNICAMP, Campinas, Sao Paulo, Brazil
- Instituto Nacional de Ciência e Tecnologia de Obesidade e Diabetes, Sao Paulo, Brazil
- * E-mail: (EMC); (AN)
| | - Angel Nadal
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, CIBERDEM, Elche, Spain
- * E-mail: (EMC); (AN)
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27
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Batista TM, Alonso-Magdalena P, Vieira E, Amaral MEC, Cederroth CR, Nef S, Quesada I, Carneiro EM, Nadal A. Short-term treatment with bisphenol-A leads to metabolic abnormalities in adult male mice. PLoS One 2012. [PMID: 22470480 DOI: 10.31371/journal.pone.0033814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
Abstract
Bisphenol-A (BPA) is one of the most widespread endocrine disrupting chemicals (EDC) used as the base compound in the manufacture of polycarbonate plastics. Although evidence points to consider exposure to BPA as a risk factor for insulin resistance, its actions on whole body metabolism and on insulin-sensitive tissues are still unclear. The aim of the present work was to study the effects of low doses of BPA in insulin-sensitive peripheral tissues and whole body metabolism in adult mice. Adult mice were treated with subcutaneous injection of 100 µg/kg BPA or vehicle for 8 days. Whole body energy homeostasis was assessed with in vivo indirect calorimetry. Insulin signaling assays were conducted by western blot analysis. Mice treated with BPA were insulin resistant and had increased glucose-stimulated insulin release. BPA-treated mice had decreased food intake, lower body temperature and locomotor activity compared to control. In skeletal muscle, insulin-stimulated tyrosine phosphorylation of the insulin receptor β subunit was impaired in BPA-treated mice. This impairment was associated with a reduced insulin-stimulated Akt phosphorylation in the Thr(308) residue. Both skeletal muscle and liver displayed an upregulation of IRS-1 protein by BPA. The mitogen-activated protein kinase (MAPK) signaling pathway was also impaired in the skeletal muscle from BPA-treated mice. In the liver, BPA effects were of lesser intensity with decreased insulin-stimulated tyrosine phosphorylation of the insulin receptor β subunit.In conclusion, short-term treatment with low doses of BPA slows down whole body energy metabolism and disrupts insulin signaling in peripheral tissues. Thus, our findings support the notion that BPA can be considered a risk factor for the development of type 2 diabetes.
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Affiliation(s)
- Thiago M Batista
- Departamento de Anatomia, Biologia Celular, Fisiologia e Biofísica, Instituto de Biologia, Universidade Estadual de Campinas, UNICAMP, Campinas, Sao Paulo, Brazil
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