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Podraza J, Gutowska K, Lenartowicz A, Wąsowski M, Jonas MI, Bartoszewicz Z, Lisik W, Jonas M, Binda A, Jaworski P, Tarnowski W, Noszczyk B, Puzianowska-Kuźnicka M, Kuryłowicz A. The Role of microRNA in the Regulation of Cortisol Metabolism in the Adipose Tissue in the Course of Obesity. Int J Mol Sci 2024; 25:5058. [PMID: 38791098 PMCID: PMC11120731 DOI: 10.3390/ijms25105058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 04/30/2024] [Accepted: 05/04/2024] [Indexed: 05/26/2024] Open
Abstract
The similarity of the clinical picture of metabolic syndrome and hypercortisolemia supports the hypothesis that obesity may be associated with impaired expression of genes related to cortisol action and metabolism in adipose tissue. The expression of genes encoding the glucocorticoid receptor alpha (GR), cortisol metabolizing enzymes (HSD11B1, HSD11B2, H6PDH), and adipokines, as well as selected microRNAs, was measured by real-time PCR in adipose tissue from 75 patients with obesity, 19 patients following metabolic surgery, and 25 normal-weight subjects. Cortisol levels were analyzed by LC-MS/MS in 30 pairs of tissues. The mRNA levels of all genes studied were significantly (p < 0.05) decreased in the visceral adipose tissue (VAT) of patients with obesity and normalized by weight loss. In the subcutaneous adipose tissue (SAT), GR and HSD11B2 were affected by this phenomenon. Negative correlations were observed between the mRNA levels of the investigated genes and selected miRNAs (hsa-miR-142-3p, hsa-miR-561, and hsa-miR-579). However, the observed changes did not translate into differences in tissue cortisol concentrations, although levels of this hormone in the SAT of patients with obesity correlated negatively with mRNA levels for adiponectin. In conclusion, although the expression of genes related to cortisol action and metabolism in adipose tissue is altered in obesity and miRNAs may be involved in this process, these changes do not affect tissue cortisol concentrations.
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Affiliation(s)
- Jakub Podraza
- The Faculty of Biology and Biotechnology, Warsaw University of Life Sciences, 02-787 Warsaw, Poland;
| | - Klaudia Gutowska
- II Department of Obstetrics and Gynecology, Warsaw Medical University, 00-315 Warsaw, Poland;
| | | | - Michał Wąsowski
- Department of General Medicine and Geriatric Cardiology, Medical Centre of Postgraduate Education, 00-401 Warsaw, Poland;
| | - Marta Izabela Jonas
- Department of Human Epigenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw, Poland; (M.I.J.); (M.P.-K.)
| | - Zbigniew Bartoszewicz
- Department of Internal Medicine and Endocrinology, The Medical University of Warsaw, 02-097 Warsaw, Poland;
| | - Wojciech Lisik
- Department of General and Transplantation Surgery, The Medical University of Warsaw, 00-694 Warsaw, Poland
| | - Maurycy Jonas
- Department of General Surgery, Barska Hospital, 02-315 Warsaw, Poland;
| | - Artur Binda
- Department of General, Oncological and Bariatric Surgery, Medical Centre of Postgraduate Education, 00-401 Warsaw, Poland (W.T.)
| | - Paweł Jaworski
- Department of General, Oncological and Bariatric Surgery, Medical Centre of Postgraduate Education, 00-401 Warsaw, Poland (W.T.)
| | - Wiesław Tarnowski
- Department of General, Oncological and Bariatric Surgery, Medical Centre of Postgraduate Education, 00-401 Warsaw, Poland (W.T.)
| | - Bartłomiej Noszczyk
- Department of Plastic Surgery, Medical Centre of Postgraduate Education, 00-401 Warsaw, Poland;
| | - Monika Puzianowska-Kuźnicka
- Department of Human Epigenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw, Poland; (M.I.J.); (M.P.-K.)
- Department of Geriatrics and Gerontology, Medical Centre of Postgraduate Education, 01-826 Warsaw, Poland
| | - Alina Kuryłowicz
- Department of General Medicine and Geriatric Cardiology, Medical Centre of Postgraduate Education, 00-401 Warsaw, Poland;
- Department of Human Epigenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw, Poland; (M.I.J.); (M.P.-K.)
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2
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Tsai KHY, Shi H, Parungao RJ, Naficy S, Ding X, Ding X, Hew JJ, Wang X, Chrzanowski W, Lavery GG, Li Z, Issler-Fisher AC, Chen J, Tan Q, Maitz PK, Cooper MS, Wang Y. Skin 11β-hydroxysteroid dehydrogenase type 1 enzyme expression regulates burn wound healing and can be targeted to modify scar characteristics. BURNS & TRAUMA 2023; 11:tkac052. [PMID: 36694861 PMCID: PMC9862341 DOI: 10.1093/burnst/tkac052] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/29/2022] [Accepted: 11/16/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND Excessive scarring and fibrosis are the most severe and common complications of burn injury. Prolonged exposure to high levels of glucocorticoids detrimentally impacts on skin, leading to skin thinning and impaired wound healing. Skin can generate active glucocorticoids locally through expression and activity of the 11β-hydroxysteroid dehydrogenase type 1 enzyme (11β-HSD1). We hypothesised that burn injury would induce 11β-HSD1 expression and local glucocorticoid metabolism, which would have important impacts on wound healing, fibrosis and scarring. We additionally proposed that pharmacological manipulation of this system could improve aspects of post-burn scarring. METHODS Skin 11β-HSD1 expression in burns patients and mice was examined. The impacts of 11β-HSD1 mediating glucocorticoid metabolism on burn wound healing, scar formation and scar elasticity and quality were additionally examined using a murine 11β-HSD1 genetic knockout model. Slow-release scaffolds containing therapeutic agents, including active and inactive glucocorticoids, were developed and pre-clinically tested in mice with burn injury. RESULTS We demonstrate that 11β-HSD1 expression levels increased substantially in both human and mouse skin after burn injury. 11β-HSD1 knockout mice experienced faster wound healing than wild type mice but the healed wounds manifested significantly more collagen deposition, tensile strength and stiffness, features characteristic of excessive scarring. Application of slow-release prednisone, an inactive glucocorticoid, slowed the initial rate of wound closure but significantly reduced post-burn scarring via reductions in inflammation, myofibroblast generation, collagen production and scar stiffness. CONCLUSIONS Skin 11β-HSD1 expression is a key regulator of wound healing and scarring after burn injury. Application of an inactive glucocorticoid capable of activation by local 11β-HSD1 in skin slows the initial rate of wound closure but significantlyimproves scar characteristics post burn injury.
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Affiliation(s)
- Kevin H-Y Tsai
- Adrenal Steroid Group, ANZAC Research Institute, Concord Hospital, The University of Sydney, Sydney, NSW 2137, Australia
- Burns and Reconstructive Surgery Research Group, ANZAC Research Institute, Concord Hospital, The University of Sydney, Sydney, NSW 2137, Australia
| | - Huaikai Shi
- Burns and Reconstructive Surgery Research Group, ANZAC Research Institute, Concord Hospital, The University of Sydney, Sydney, NSW 2137, Australia
| | - Roxanne J Parungao
- Burns and Reconstructive Surgery Research Group, ANZAC Research Institute, Concord Hospital, The University of Sydney, Sydney, NSW 2137, Australia
| | - Sina Naficy
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW 2006, Australia
| | - Xiaotong Ding
- Jiangsu Provincial Engineering Research Centre of TCM External Medication Development and Application, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, China
| | - Xiaofeng Ding
- Department of Burns and Plastic Surgery, Nanjing Drum Tower Hospital Clinical College, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210008, China
| | - Jonathan J Hew
- Burns and Reconstructive Surgery Research Group, ANZAC Research Institute, Concord Hospital, The University of Sydney, Sydney, NSW 2137, Australia
| | - Xiaosuo Wang
- Heart Research Institute, The University of Sydney, Sydney, NSW 2006 , Australia
| | - Wojciech Chrzanowski
- Sydney Nano Institute, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
| | - Gareth G Lavery
- Department of Biosciences, Centre for Healthy Ageing and Understanding Disease, Nottingham Trent University, NG1 4BU, UK
| | - Zhe Li
- Burns and Reconstructive Surgery Unit, Concord Repatriation General Hospital, Sydney, NSW 2137, Australia
| | - Andrea C Issler-Fisher
- Burns and Reconstructive Surgery Unit, Concord Repatriation General Hospital, Sydney, NSW 2137, Australia
| | - Jun Chen
- Jiangsu Provincial Engineering Research Centre of TCM External Medication Development and Application, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, China
| | - Qian Tan
- Department of Burns and Plastic Surgery, Nanjing Drum Tower Hospital Clinical College, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210008, China
| | - Peter K Maitz
- Burns and Reconstructive Surgery Research Group, ANZAC Research Institute, Concord Hospital, The University of Sydney, Sydney, NSW 2137, Australia
- Burns and Reconstructive Surgery Unit, Concord Repatriation General Hospital, Sydney, NSW 2137, Australia
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Ye J, Zhao X, Xue H, Zou X, Liu G, Deng M, Sun B, Guo Y, Liu D, Li Y. RNA-Seq Reveals miRNA and mRNA Co-regulate Muscle Differentiation in Fetal Leizhou Goats. Front Vet Sci 2022; 9:829769. [PMID: 35400087 PMCID: PMC8990838 DOI: 10.3389/fvets.2022.829769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
Muscle differentiation is an essential link in animal growth and development, and microRNA and mRNA are indispensable in skeletal muscle differentiation. To improve the meat quality and production of the Leizhou goat, it is vital to understand the molecular mechanism by which its skeletal muscle differentiates. By RNA sequencing (RNA-SEQ), we established miRNA-mRNA profiles of Leizhou goats at three stages: fetal day 70, 90, and 120. There were 991 differently expressed mRNAs and 39 differentially expressed miRNAs found, with the differentially expressed mRNAs mainly enriched in calcium ion binding, ECM-receptor interaction, and Focal adhesion. CKM and MYH3, two muscle differentiation markers, were significantly differentially expressed during this period. In addition, we found that chi-miR-129-5p, chi-miR-433, and chi-miR-24-3p co-regulate muscle differentiation with their target genes. Finally, we can confirm that muscle differentiation occurred in Leizhou goat between 90 and 120 days of the fetus. This study is helpful to better explore the molecular mechanism of goat muscle differentiation.
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Affiliation(s)
- Junning Ye
- College of Animal Science, South China Agricultural University, Guangzhou, China
- State Key Laboratory of Livestock and Poultry Breeding, Guangdong Key Laboratory of Animal Breeding and Nutrition, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou, China
- National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
| | - Xiuhui Zhao
- College of Animal Science, South China Agricultural University, Guangzhou, China
- State Key Laboratory of Livestock and Poultry Breeding, Guangdong Key Laboratory of Animal Breeding and Nutrition, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou, China
- National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
| | - Huiwen Xue
- College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Xian Zou
- State Key Laboratory of Livestock and Poultry Breeding, Guangdong Key Laboratory of Animal Breeding and Nutrition, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Guangbin Liu
- College of Animal Science, South China Agricultural University, Guangzhou, China
- National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
| | - Ming Deng
- College of Animal Science, South China Agricultural University, Guangzhou, China
- National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
| | - Baoli Sun
- College of Animal Science, South China Agricultural University, Guangzhou, China
- National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
| | - Yongqing Guo
- College of Animal Science, South China Agricultural University, Guangzhou, China
- National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
| | - Dewu Liu
- College of Animal Science, South China Agricultural University, Guangzhou, China
- National Local Joint Engineering Research Center of Livestock and Poultry, South China Agricultural University, Guangzhou, China
| | - Yaokun Li
- College of Animal Science, South China Agricultural University, Guangzhou, China
- *Correspondence: Yaokun Li
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Shirif AZ, Kovačević S, Brkljačić J, Teofilović A, Elaković I, Djordjevic A, Matić G. Decreased Glucocorticoid Signaling Potentiates Lipid-Induced Inflammation and Contributes to Insulin Resistance in the Skeletal Muscle of Fructose-Fed Male Rats Exposed to Stress. Int J Mol Sci 2021; 22:ijms22137206. [PMID: 34281257 PMCID: PMC8269441 DOI: 10.3390/ijms22137206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 06/25/2021] [Accepted: 06/28/2021] [Indexed: 01/03/2023] Open
Abstract
The modern lifestyle brings both excessive fructose consumption and daily exposure to stress which could lead to metabolic disturbances and type 2 diabetes. Muscles are important points of glucose and lipid metabolism, with a crucial role in the maintenance of systemic energy homeostasis. We investigated whether 9-week fructose-enriched diet, with and without exposure to 4-week unpredictable stress, disturbs insulin signaling in the skeletal muscle of male rats and evaluated potential contributory roles of muscle lipid metabolism, glucocorticoid signaling and inflammation. The combination of fructose-enriched diet and stress increased peroxisome proliferator-activated receptors-α and -δ and stimulated lipid uptake, lipolysis and β-oxidation in the muscle of fructose-fed stressed rats. Combination of treatment also decreased systemic insulin sensitivity judged by lower R-QUICKI, and lowered muscle protein content and stimulatory phosphorylations of insulin receptor supstrate-1 and Akt, as well as the level of 11β-hydroxysteroid dehydrogenase type 1 and glucocorticoid receptor. At the same time, increased levels of protein tyrosine phosphatase-1B, nuclear factor-κB, tumor necrosis factor-α, were observed in the muscle of fructose-fed stressed rats. Based on these results, we propose that decreased glucocorticoid signaling in the skeletal muscle can make a setting for lipid-induced inflammation and the development of insulin resistance in fructose-fed stressed rats.
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Doig CL, Zielinska AE, Fletcher RS, Oakey LA, Elhassan YS, Garten A, Cartwright D, Heising S, Alsheri A, Watson DG, Prehn C, Adamski J, Tennant DA, Lavery GG. Induction of the nicotinamide riboside kinase NAD + salvage pathway in a model of sarcoplasmic reticulum dysfunction. Skelet Muscle 2020; 10:5. [PMID: 32075690 PMCID: PMC7031948 DOI: 10.1186/s13395-019-0216-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 10/15/2019] [Indexed: 01/22/2023] Open
Abstract
Background Hexose-6-Phosphate Dehydrogenase (H6PD) is a generator of NADPH in the Endoplasmic/Sarcoplasmic Reticulum (ER/SR). Interaction of H6PD with 11β-hydroxysteroid dehydrogenase type 1 provides NADPH to support oxo-reduction of inactive to active glucocorticoids, but the wider understanding of H6PD in ER/SR NAD(P)(H) homeostasis is incomplete. Lack of H6PD results in a deteriorating skeletal myopathy, altered glucose homeostasis, ER stress and activation of the unfolded protein response. Here we further assess muscle responses to H6PD deficiency to delineate pathways that may underpin myopathy and link SR redox status to muscle wide metabolic adaptation. Methods We analysed skeletal muscle from H6PD knockout (H6PDKO), H6PD and NRK2 double knockout (DKO) and wild-type (WT) mice. H6PDKO mice were supplemented with the NAD+ precursor nicotinamide riboside. Skeletal muscle samples were subjected to biochemical analysis including NAD(H) measurement, LC-MS based metabolomics, Western blotting, and high resolution mitochondrial respirometry. Genetic and supplement models were assessed for degree of myopathy compared to H6PDKO. Results H6PDKO skeletal muscle showed adaptations in the routes regulating nicotinamide and NAD+ biosynthesis, with significant activation of the Nicotinamide Riboside Kinase 2 (NRK2) pathway. Associated with changes in NAD+ biosynthesis, H6PDKO muscle had impaired mitochondrial respiratory capacity with altered mitochondrial acylcarnitine and acetyl-CoA metabolism. Boosting NAD+ levels through the NRK2 pathway using the precursor nicotinamide riboside elevated NAD+/NADH but had no effect to mitigate ER stress and dysfunctional mitochondrial respiratory capacity or acetyl-CoA metabolism. Similarly, H6PDKO/NRK2 double KO mice did not display an exaggerated timing or severity of myopathy or overt change in mitochondrial metabolism despite depression of NAD+ availability. Conclusions These findings suggest a complex metabolic response to changes in muscle SR NADP(H) redox status that result in impaired mitochondrial energy metabolism and activation of cellular NAD+ salvage pathways. It is possible that SR can sense and signal perturbation in NAD(P)(H) that cannot be rectified in the absence of H6PD. Whether NRK2 pathway activation is a direct response to changes in SR NAD(P)(H) availability or adaptation to deficits in metabolic energy availability remains to be resolved.
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Affiliation(s)
- Craig L Doig
- Institute of Metabolism and Systems Research, University of Birmingham, 2nd Floor IBR Tower, Edgbaston, Birmingham, B15 2TT, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Agnieszka E Zielinska
- Institute of Metabolism and Systems Research, University of Birmingham, 2nd Floor IBR Tower, Edgbaston, Birmingham, B15 2TT, UK
| | - Rachel S Fletcher
- Institute of Metabolism and Systems Research, University of Birmingham, 2nd Floor IBR Tower, Edgbaston, Birmingham, B15 2TT, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Lucy A Oakey
- Institute of Metabolism and Systems Research, University of Birmingham, 2nd Floor IBR Tower, Edgbaston, Birmingham, B15 2TT, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Yasir S Elhassan
- Institute of Metabolism and Systems Research, University of Birmingham, 2nd Floor IBR Tower, Edgbaston, Birmingham, B15 2TT, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Antje Garten
- Institute of Metabolism and Systems Research, University of Birmingham, 2nd Floor IBR Tower, Edgbaston, Birmingham, B15 2TT, UK
| | - David Cartwright
- Institute of Metabolism and Systems Research, University of Birmingham, 2nd Floor IBR Tower, Edgbaston, Birmingham, B15 2TT, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Silke Heising
- Institute of Metabolism and Systems Research, University of Birmingham, 2nd Floor IBR Tower, Edgbaston, Birmingham, B15 2TT, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Ahmed Alsheri
- Strathclyde Institute of Pharmacy and Medical Sciences, Hamnett Wing John Arbuthnott Building, Glasgow, G4 0RE, UK
| | - David G Watson
- Strathclyde Institute of Pharmacy and Medical Sciences, Hamnett Wing John Arbuthnott Building, Glasgow, G4 0RE, UK
| | - Cornelia Prehn
- Research Unit of Molecular Endocrinology and Metabolism, Helmholtz Zentrum Munchen GmbH, Ingolstadter Landstrasse 1, D-85764, Neuherberg, Germany.,Lehrstuhl für Experimentelle Genetik, Technische Universität München, Freising, Germany.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117593, Singapore
| | - Jerzy Adamski
- Research Unit of Molecular Endocrinology and Metabolism, Helmholtz Zentrum Munchen GmbH, Ingolstadter Landstrasse 1, D-85764, Neuherberg, Germany.,Lehrstuhl für Experimentelle Genetik, Technische Universität München, Freising, Germany.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117593, Singapore
| | - Daniel A Tennant
- Institute of Metabolism and Systems Research, University of Birmingham, 2nd Floor IBR Tower, Edgbaston, Birmingham, B15 2TT, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Gareth G Lavery
- Institute of Metabolism and Systems Research, University of Birmingham, 2nd Floor IBR Tower, Edgbaston, Birmingham, B15 2TT, UK. .,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK. .,MRC-ARUK Centre for Musculoskeletal Ageing Research, University of Birmingham, Birmingham, UK.
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6
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Zielinska AE, Fletcher RS, Sherlock M, Doig CL, Lavery GG. Cellular and genetic models of H6PDH and 11β-HSD1 function in skeletal muscle. Cell Biochem Funct 2017; 35:269-277. [PMID: 28749080 PMCID: PMC5601182 DOI: 10.1002/cbf.3272] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 04/27/2017] [Accepted: 06/25/2017] [Indexed: 12/27/2022]
Abstract
Glucocorticoids are important for skeletal muscle energy metabolism, regulating glucose utilization, insulin sensitivity, and muscle mass. Nicotinamide adenine dinucleotide phosphate‐dependent 11β‐hydroxysteroid dehydrogenase type 1 (11β‐HSD1)‐mediated glucocorticoid activation in the sarcoplasmic reticulum (SR) is integral to mediating the detrimental effects of glucocorticoid excess in muscle. 11β‐Hydroxysteroid dehydrogenase type 1 activity requires glucose‐6‐phosphate transporter (G6PT)‐mediated G6P transport into the SR for its metabolism by hexose‐6‐phosphate dehydrogenase (H6PDH) for NADPH generation. Here, we examine the G6PT/H6PDH/11β‐HSD1 triad in differentiating myotubes and explore the consequences of muscle‐specific knockout of 11β‐HSD1 and H6PDH. 11β‐Hydroxysteroid dehydrogenase type 1 expression and activity increase with myotube differentiation and in response to glucocorticoids. Hexose‐6‐phosphate dehydrogenase shows some elevation in expression with differentiation and in response to glucocorticoid, while G6PT appears largely unresponsive to these particular conditions. When examining 11β‐HSD1 muscle‐knockout mice, we were unable to detect significant decrements in activity, despite using a well‐validated muscle‐specific Cre transgene and confirming high‐level recombination of the floxed HSD11B1 allele. We propose that the level of recombination at the HSD11B1 locus may be insufficient to negate basal 11β‐HSD1 activity for a protein with a long half‐life. Hexose‐6‐phosphate dehydrogenase was undetectable in H6PDH muscle‐knockout mice, which display the myopathic phenotype seen in global KO mice, validating the importance of SR NADPH generation. We envisage these data and models finding utility when investigating the muscle‐specific functions of the 11β‐HSD1/G6PT/H6PDH triad.
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Affiliation(s)
- Agnieszka E Zielinska
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Rachel S Fletcher
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Mark Sherlock
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Craig L Doig
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Gareth G Lavery
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
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