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Baird HJM, Shun-Shion AS, Mendes de Oliveira E, Stalder D, Liang L, Eden J, Chambers JE, Farooqi IS, Gershlick DC, Fazakerley DJ. A quantitative pipeline to assess secretion of human leptin coding variants reveals mechanisms underlying leptin deficiencies. J Biol Chem 2024; 300:107562. [PMID: 39002670 DOI: 10.1016/j.jbc.2024.107562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 07/01/2024] [Accepted: 07/03/2024] [Indexed: 07/15/2024] Open
Abstract
The hormone leptin, primarily secreted by adipocytes, plays a crucial role in regulating whole-body energy homeostasis. Homozygous loss-of-function mutations in the leptin gene (LEP) cause hyperphagia and severe obesity, primarily through alterations in leptin's affinity for its receptor or changes in serum leptin concentrations. Although serum concentrations are influenced by various factors (e.g., gene expression, protein synthesis, stability in the serum), proper delivery of leptin from its site of synthesis in the endoplasmic reticulum via the secretory pathway to the extracellular serum is a critical step. However, the regulatory mechanisms and specific machinery involved in this trafficking route, particularly in the context of human LEP mutations, remain largely unexplored. We have employed the Retention Using Selective Hooks system to elucidate the secretory pathway of leptin. We have refined this system into a medium-throughput assay for examining the pathophysiology of a range of obesity-associated LEP variants. Our results reveal that leptin follows the default secretory pathway, with no additional regulatory steps identified prior to secretion. Through screening of leptin variants, we identified three mutations that lead to proteasomal degradation of leptin and one variant that significantly decreased leptin secretion, likely through aberrant disulfide bond formation. These observations have identified novel pathogenic effects of leptin variants, which can be informative for therapeutics and diagnostics. Finally, our novel quantitative screening platform can be adapted for other secreted proteins.
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Affiliation(s)
- Harry J M Baird
- Metabolic Research Laboratory, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Amber S Shun-Shion
- Metabolic Research Laboratory, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Edson Mendes de Oliveira
- Metabolic Research Laboratory, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Danièle Stalder
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Lu Liang
- Metabolic Research Laboratory, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Jessica Eden
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Joseph E Chambers
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - I Sadaf Farooqi
- Metabolic Research Laboratory, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom.
| | - David C Gershlick
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom.
| | - Daniel J Fazakerley
- Metabolic Research Laboratory, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom.
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Recent Advances in the Knowledge of the Mechanisms of Leptin Physiology and Actions in Neurological and Metabolic Pathologies. Int J Mol Sci 2023; 24:ijms24021422. [PMID: 36674935 PMCID: PMC9860943 DOI: 10.3390/ijms24021422] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/05/2023] [Accepted: 01/07/2023] [Indexed: 01/13/2023] Open
Abstract
Excess body weight is frequently associated with low-grade inflammation. Evidence indicates a relationship between obesity and cancer, as well as with other diseases, such as diabetes and non-alcoholic fatty liver disease, in which inflammation and the actions of various adipokines play a role in the pathological mechanisms involved in these disorders. Leptin is mainly produced by adipose tissue in proportion to fat stores, but it is also synthesized in other organs, where leptin receptors are expressed. This hormone performs numerous actions in the brain, mainly related to the control of energy homeostasis. It is also involved in neurogenesis and neuroprotection, and central leptin resistance is related to some neurological disorders, e.g., Parkinson's and Alzheimer's diseases. In peripheral tissues, leptin is implicated in the regulation of metabolism, as well as of bone density and muscle mass. All these actions can be affected by changes in leptin levels and the mechanisms associated with resistance to this hormone. This review will present recent advances in the molecular mechanisms of leptin action and their underlying roles in pathological situations, which may be of interest for revealing new approaches for the treatment of diseases where the actions of this adipokine might be compromised.
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Essential Amino Acids-Rich Diet Decreased Adipose Tissue Storage in Adult Mice: A Preliminary Histopathological Study. Nutrients 2022; 14:nu14142915. [PMID: 35889872 PMCID: PMC9316883 DOI: 10.3390/nu14142915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/11/2022] [Accepted: 07/13/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Excess body adipose tissue accumulation is a common and growing health problem caused by an unbalanced diet and/or junk food. Although the effects of dietary fat and glucose on lipid metabolism regulation are well known, those of essential amino acids (EAAs) have been poorly investigated. Our aim was to study the influence of a special diet containing all EAAs on retroperitoneal white adipose tissue (rpWAT) and interscapular brown adipose tissue (BAT) of mice. Methods: Two groups of male Balb/C mice were used. The first was fed with a standard diet. The second was fed with an EAAs-rich diet (EAARD). After 3 weeks, rpWAT and BAT were removed and prepared for subsequent immunohistochemical analysis. Results: EAARD, although consumed significantly less, moderately reduced body weight and BAT, but caused a massive reduction in rpWAT. Conversely, the triceps muscle increased in mass. In rpWAT, the size of adipocytes was very small, with increases in leptin, adiponectin and IL-6 immunostaining. In BAT, there was a reduction in lipid droplet size and a simultaneous increase in UCP-1 and SIRT-3. Conclusions: A diet containing a balanced mixture of free EAA may modulate body adiposity in mice, promoting increased thermogenesis.
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Malebary SJ, Alzahrani E, Khan YD. A comprehensive tool for accurate identification of methyl-Glutamine sites. J Mol Graph Model 2021; 110:108074. [PMID: 34768228 DOI: 10.1016/j.jmgm.2021.108074] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/15/2021] [Accepted: 11/02/2021] [Indexed: 11/16/2022]
Abstract
Methylation is a biochemical process involved in nearly all of the human body functions. Glutamine is considered an indispensable amino acid that is susceptible to methylation via post-translational modification (PTM). Modern research has proved that methylation plays a momentous role in the progression of most types of cancers. Therefore, there is a need for an effective method to predict glutamine sites vulnerable to methylation accurately and inexpensively. The motive of this study is the formulation of an accurate method that could predict such sites with high accuracy. Various computationally intelligent classifiers were employed for their formulation and evaluation. Rigorous validations prove that deep learning performs best as compared to other classifiers. The accuracy (ACC) and the area under the receiver operating curve (AUC) obtained by 10-fold cross-validation was 0.962 and 0.981, while with the jackknife testing, it was 0.968 and 0.980, respectively. From these results, it is concluded that the proposed methodology works sufficiently well for the prediction of methyl-glutamine sites. The webserver's code, developed for the prediction of methyl-glutamine sites, is freely available at https://github.com/s20181080001/WebServer.git. The code can easily be set up by any intermediate-level Python user.
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Affiliation(s)
- Sharaf J Malebary
- Department of Information Technology, Faculty of Computing and Information Technology, King Abdulaziz University, P.O. Box 344, Rabigh, 21911, Saudi Arabia.
| | - Ebraheem Alzahrani
- Department of Mathematics, Faculty of Science, King Abdulaziz University, P. O. Box 80203, Jeddah, 21589, Saudi Arabia.
| | - Yaser Daanial Khan
- Department of Computer Science, School of Systems and Technology, University of Management and Technology, Lahore, Pakistan.
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Senamontree S, Lakthan T, Charoenpanich P, Chanchao C, Charoenpanich A. Betulinic acid decreases lipid accumulation in adipogenesis-induced human mesenchymal stem cells with upregulation of PGC-1α and UCP-1 and post-transcriptional downregulation of adiponectin and leptin secretion. PeerJ 2021; 9:e12321. [PMID: 34721992 PMCID: PMC8520689 DOI: 10.7717/peerj.12321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/25/2021] [Indexed: 12/24/2022] Open
Abstract
Background Controlling cellular functions, including stem cell growth and differentiation, can be the key for the treatment of metabolic disorders, such as type II diabetes mellitus (T2DM). Previously identified as peroxisome proliferator-activated receptor gamma (PPARγ) antagonist, betulinic acid (BA) may have the capability to control stem cell homeostasis, benefiting T2DM treatment. In this study, the effects of BA on osteogenesis and adipogenesis mechanisms of human mesenchymal stem cells (hMSCs) were investigated. Results We observed that BA increased hMSC osteogenesis by enhancing the alkaline phosphatase activity, calcium deposition, and mRNA expressions of osteogenic markers, namely, runt-related transcription factor 2, osteocalcin, and osteopontin. In addition, BA decreased hMSC adipogenesis with the decrease in glycerol-3-phosphate dehydrogenase activity, reduced intracellular lipid accumulations, down-regulated CCAAT-enhancer-binding protein alpha, and suppressed post-transcriptional adiponectin and leptin secretion. BA increased the brown adipocyte characteristics with the increase in the ratio of small lipid droplets and glucose uptake. Furthermore, the mRNA expressions of brown adipocyte markers, namely, PPARγ coactivator one alpha, uncoupling protein 1, and interleukin-6 increased. Conclusions Our results uncovered the mechanisms of how BA improved glucose and lipid metabolisms by decreasing white adipogenesis and increasing brown adipogenesis. Altogether, BA may be used for balancing glucose metabolisms without the potential side effects on bone loss or weight gain.
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Affiliation(s)
- Sasithon Senamontree
- Department of Biology, Faculty of Science, Silpakorn University, Nakhon Pathom, Thailand
| | - Thitiporn Lakthan
- Department of Biology, Faculty of Science, Silpakorn University, Nakhon Pathom, Thailand
| | - Pornsri Charoenpanich
- Department of Food Technology, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom, Thailand
| | - Chanpen Chanchao
- Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Adisri Charoenpanich
- Department of Biology, Faculty of Science, Silpakorn University, Nakhon Pathom, Thailand
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Zhong B, Ma S, Wang DH. Ablation of TRPV1 Elevates Nocturnal Blood Pressure in Western Diet-fed Mice. Curr Hypertens Rev 2020; 15:144-153. [PMID: 30381083 PMCID: PMC6635649 DOI: 10.2174/1573402114666181031141840] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 09/24/2018] [Accepted: 10/24/2018] [Indexed: 12/28/2022]
Abstract
Background: This study tested the hypothesis that genetically ablation of transient receptor potential vanilloid type 1 (TRPV1) exacerbates impairment of baroreflex in mice fed a western diet (WD) and leads to distinct diurnal and nocturnal blood pressure patterns. Methods: TRPV1 gene knockout (TRPV1-/-) and wild-type (WT) mice were given a WD or normal diet (CON) for 4 months. Results: Capsaicin, a selective TRPV1 agonist, increased ipsilateral afferent renal nerve activity in WT but not TRPV1-/- mice. The sensitivity of renal sympathetic nerve activity and heart rate responses to baroreflex were reduced in TRPV1-/--CON and WT-WD and further decreased in TRPV1-/--WD compared to the WT-CON group. Urinary norepinephrine and serum insulin and leptin at day and night were increased in WT-WD and TRPV1-/--WD, with further elevation at night in TRPV1-/--WD. WD intake increased leptin, IL-6, and TNF-α in adipose tissue, and TNF-α antagonist III, R-7050, decreased leptin in TRPV1-/--WD. The urinary albumin level was higher in TRPV1-/--WD than WT-WD. Blood pressure was not dif-ferent during daytime among all groups, but increased at night in the TRPV1-/--WD group compared with other groups. Conclusions: TRPV1 ablation leads to elevated nocturnal but not diurnal blood pressure, which is probably attributed to fur-ther enhancement of sympathetic drives at night.
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Affiliation(s)
- Beihua Zhong
- Division of Nanomedicine and Molecular Intervention, Department of Medicine, Michigan State University, East Lansing, Michigan MI 48824, United States
| | - Shuangtao Ma
- Division of Nanomedicine and Molecular Intervention, Department of Medicine, Michigan State University, East Lansing, Michigan MI 48824, United States
| | - Donna H Wang
- Division of Nanomedicine and Molecular Intervention, Department of Medicine, Michigan State University, East Lansing, Michigan MI 48824, United States.,Neuroscience Program, Michigan State University, East Lansing, Michigan MI 48824, United States.,Cell & Molecular Biology Program, Michigan State University, East Lansing, Michigan MI 48824, United States
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Lipid Deposition and Mobilisation in Atlantic Salmon Adipocytes. Int J Mol Sci 2020; 21:ijms21072332. [PMID: 32230940 PMCID: PMC7177889 DOI: 10.3390/ijms21072332] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/22/2020] [Accepted: 03/25/2020] [Indexed: 12/13/2022] Open
Abstract
The present study aimed to elucidate how Atlantic salmon adipocytes pre-enriched with palmitic (16:0, PA), oleic (18:1n−9, OA), or eicosapentaenoic (20:5n−3, EPA) acid respond to a fasting condition mimicked by nutrient deprivation and glucagon. All experimental groups were supplemented with radiolabeled PA to trace secreted lipids and distribution of radioactivity in different lipid classes. There was a higher content of intracellular lipid droplets in adipocytes pre-enriched with OA than in adipocytes pre-enriched with PA or EPA. In the EPA group, the radiolabeled PA was mainly esterified in phospholipids and triacylglycerols, whereas in the OA and PA groups, the radioactivity was mainly recovered in phospholipids and cholesterol-ester. By subjecting the experimental groups to nutrient-deprived media supplemented with glucagon, lipolysis occurred in all groups, although to a lower extent in the OA group. The lipids were mainly secreted as esterified lipids in triacylglycerols and phospholipids, indicating mobilization in lipoproteins. A significant proportion was secreted as free fatty acids and glycerol. Leptin secretion was reduced in all experimental groups in response to fasting, while the mitochondria area responded to changes in the energy supply and demand by increasing after 3 h of fasting. Overall, different lipid classes in adipocytes influenced their mobilization during fasting.
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Zachurzok A, Ranke MB, Flehmig B, Jakubek-Kipa K, Marcinkiewicz K, Mazur A, Petriczko E, Pridzun L, von Schnurbein J, Walczak M, Malecka-Tendera E, Wabitsch M, Brandt S. Relative leptin deficiency in children with severe early-onset obesity (SEOO) - results of the Early-onset Obesity and Leptin - German-Polish Study (EOL-GPS). J Pediatr Endocrinol Metab 2020; 33:255-263. [PMID: 31927523 DOI: 10.1515/jpem-2019-0469] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 11/18/2019] [Indexed: 01/13/2023]
Abstract
Background Severe early-onset obesity (SEOO) in children is a common feature of monogenic obesity. Gene defects of the leptin-melanocortin pathway can be analysed biochemically and genetically. The aim of this study was to search for children with leptin deficiency or biologically inactive leptin in a cohort of children with SEOO and to study associations between leptin parameters and anthropometric data. Methods The cohort included n = 50 children with SEOO (22 boys) who were recruited at one of four study centres (Germany: Ulm; Poland: Katowice, Szczecin, Rzeszow) between October 2015 and October 2017. Weight (kg) and height (m) were measured, Tanner stage was obtained and a fasting serum blood sample was taken. Serum levels of total leptin (LEP, ng/mL), biologically active leptin (bioLEP, ng/mL) and soluble leptin receptor (sLEPR, ng/mL) were measured. The body mass index (BMI [kg/m2]), BMI z-score (World Health Organization [WHO]), quotient of bioLEP/LEP and leptin-standard deviation score (LEP-SDS) (Tanner stage, BMI and sex-adjusted) were calculated. Results We did not find any child with leptin deficiency or biologically inactive leptin in our cohort. The serum LEP and bioLEP levels were strongly correlated with age (r = 0.50, p < 0.05) and BMI (r = 0.70; p < 0.0001). Girls had higher LEP and bioLEP levels (49.7 ± 35.9 vs. 37.1 ± 25.5 ng/mL, p > 0.05) as well as lower LEP-SDS than boys (-1.77 ± 2.61 vs. -1.40 ± 2.60, p > 0.05). sLEPR levels were negatively correlated with BMI values (r = -0.44; p < 0.05), LEP (r = -0.39; p < 0.05) and bioLEP levels (r = -0.37; p < 0.05). Interestingly, there was a strong inverse relationship between LEP-SDS and BMI (r = -0.72, p < 0.001). Conclusions In this cohort with SEOO, we identified no new cases of children with leptin deficiency or bioinactive leptin. A strong negative correlation between the LEP-SDS and BMI values could be interpreted as relative leptin deficiency in children with SEOO. In case this hypothesis can be confirmed, these children would benefit from a substitution therapy with methionyl human leptin (metreleptin™).
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Affiliation(s)
- Agnieszka Zachurzok
- Department of Pediatrics and Pediatric Endocrinology, Medical University of Silesia, School of Medicine in Katowice, Katowice, Poland
| | | | | | | | - Katarzyna Marcinkiewicz
- Department of Pediatrics, Endocrinology, Diabetology, Metabolic Disorders and Cardiology of Developmental Age, Pomeranian Medical University, Szczecin, Poland
| | - Artur Mazur
- University of Rzeszow, Department of Pediatrics, Rzeszow, Poland
| | - Elzbieta Petriczko
- Department of Pediatrics, Endocrinology, Diabetology, Metabolic Disorders and Cardiology of Developmental Age, Pomeranian Medical University, Szczecin, Poland
| | | | - Julia von Schnurbein
- Center for Rare Endocrine Diseases, Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, Ulm, Germany
| | - Mieczyslaw Walczak
- Pomeranian Medical University, Department of Pediatrics, Endocrinology and Diabetes, Szczecin, Poland
| | - Ewa Malecka-Tendera
- Department of Pediatrics and Pediatric Endocrinology, Medical University of Silesia, School of Medicine in Katowice, Katowice, Poland
| | - Martin Wabitsch
- Center for Rare Endocrine Diseases, Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, Ulm, Germany
| | - Stephanie Brandt
- Center for Rare Endocrine Diseases, Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, Ulm, Germany
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Gioldasi S, Karvela A, Rojas-Gil AP, Rodi M, de Lastic AL, Thomas I, Spiliotis BE, Mouzaki A. Metabolic Association between Leptin and the Corticotropin Releasing Hormone. Endocr Metab Immune Disord Drug Targets 2020; 19:458-466. [PMID: 30727936 PMCID: PMC7360915 DOI: 10.2174/1871530319666190206165626] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 10/31/2018] [Accepted: 12/27/2018] [Indexed: 01/29/2023]
Abstract
Objective In healthy individuals, leptin is produced from adipose tissue and is secreted into the circulation to communicate energy balance status to the brain and control fat metabolism. Corticotropin-Releasing Hormone (CRH) is synthesized in the hypothalamus and regulates stress responses. Among the many adipokines and hormones that control fat metabolism, leptin and CRH both curb appetite and inhibit food intake. Despite numerous reports on leptin and CRH properties and function, little has been actually shown about their association in the adipose tissue environment. Methods In this article, we summarized the salient information on leptin and CRH in relation to metabolism. We also investigated the direct effect of recombinant CRH on leptin secretion by primary cultures of human adipocytes isolated from subcutaneous abdominal adipose tissue of 7 healthy children and adolescents, and measured CRH and leptin levels in plasma collected from peripheral blood of 24 healthy children and adolescents to assess whether a correlation exists between CRH and leptin levels in the periphery. Results and Conclusion The available data indicate that CRH exerts a role in the regulation of leptin in human adipocytes. We show that CRH downregulates leptin production by mature adipocytes and that a strong negative correlation exists between CRH and leptin levels in the periphery, and suggest the possible mechanisms of CRH control of leptin. Delineation of CRH control of leptin production by adipocytes may explain unknown pathogenic mechanisms linking stress and metabolism.
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Affiliation(s)
- Sofia Gioldasi
- Division of Hematology, Department of Internal Medicine, Medical School, University of Patras, Patras, Greece
| | - Alexia Karvela
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, Medical School, University of Patras, Patras, Greece
| | | | - Maria Rodi
- Division of Hematology, Department of Internal Medicine, Medical School, University of Patras, Patras, Greece
| | - Anne-Lise de Lastic
- Division of Hematology, Department of Internal Medicine, Medical School, University of Patras, Patras, Greece
| | - Iason Thomas
- Department of Allergy, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
| | - Bessie E Spiliotis
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, Medical School, University of Patras, Patras, Greece
| | - Athanasia Mouzaki
- Division of Hematology, Department of Internal Medicine, Medical School, University of Patras, Patras, Greece
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Mohtar O, Ozdemir C, Roy D, Shantaram D, Emili A, Kandror KV. Egr1 mediates the effect of insulin on leptin transcription in adipocytes. J Biol Chem 2019; 294:5784-5789. [PMID: 30846562 DOI: 10.1074/jbc.ac119.007855] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/04/2019] [Indexed: 12/14/2022] Open
Abstract
In mammals, leptin production in adipocytes is up-regulated by feeding and insulin. Although this regulatory connection is central to all physiological effects of leptin, its molecular mechanism remains unknown. Here, we show that the transcription factor early growth response 1, Egr1, is rapidly but transiently induced by insulin in adipose cells both in vitro and in vivo, and its induction is followed by an increase in leptin transcription. ChIP and luciferase assays demonstrate that Egr1 directly binds to and activates the leptin promoter. Interestingly, the lipid droplet protein FSP27 may work as a co-factor for Egr1 in regulating leptin expression. By using siRNA-mediated knockout of Egr1 along with its overexpression in adipocytes, we demonstrate that Egr1 is both necessary and sufficient for the stimulatory effect of insulin on leptin transcription.
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Affiliation(s)
- Omar Mohtar
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Cafer Ozdemir
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Debasish Roy
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Dharti Shantaram
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Andrew Emili
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Konstantin V Kandror
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118.
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Marques-Oliveira GH, Silva TM, Lima WG, Valadares HMS, Chaves VE. Insulin as a hormone regulator of the synthesis and release of leptin by white adipose tissue. Peptides 2018; 106:49-58. [PMID: 29953915 DOI: 10.1016/j.peptides.2018.06.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 06/20/2018] [Accepted: 06/24/2018] [Indexed: 02/09/2023]
Abstract
Leptin and its receptor are widely distributed in several tissues, mainly in white adipose tissue. The serum leptin is highly correlated with body mass index in rodents and humans, being documented that leptin levels reduces in the fasting state and increase during refeeding, similarly to insulin release by pancreatic islets. Insulin appears to increase leptin mRNA and protein expression and its release by adipocytes. Some studies have suggested that insulin acts through the activation of the transcription factors: sterol regulatory element binding protein 1 (SREBP1), CCAAT enhancer binding protein-α (C/EBP-α) and specificity protein 1 (Sp1). Insulin stimulates the release of preformed and newly synthesized leptin by adipocytes through its signaling cascade. Its effects are blocked by inhibitors of the insulin signaling pathway, as well as by inhibitors of protein synthesis and agents that increase the intracellular cAMP. The literature data suggest that chronic hyperinsulinemia increases serum leptin levels in humans and rodents. In this review, we summarized the most updated knowledge on the effects of insulin on serum leptin levels, presenting the cell mechanisms that control leptin synthesis and release by the white adipose tissue.
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Affiliation(s)
| | - Thaís Marques Silva
- Laboratory of Physiology, Federal University of São João del-Rei, Divinópolis, Minas Gerais, Brazil
| | - William Gustavo Lima
- Laboratory of Physiology, Federal University of São João del-Rei, Divinópolis, Minas Gerais, Brazil
| | | | - Valéria Ernestânia Chaves
- Laboratory of Physiology, Federal University of São João del-Rei, Divinópolis, Minas Gerais, Brazil.
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Zhang J, Jin J, Liu J, He Y, Zhang P, Ye W, Zhu W, Li M. A study of the correlation of insulin resistance and leptin with inflammatory factors and vascular endothelial injury in T2DM patients with CHD. Exp Ther Med 2018; 16:265-269. [PMID: 29896248 PMCID: PMC5995089 DOI: 10.3892/etm.2018.6170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 04/17/2018] [Indexed: 12/18/2022] Open
Abstract
The purpose of this study was to explore the correlation of insulin resistance (IR) and leptin with inflammatory factors and vascular endothelial injury in patients with type 2 diabetes mellitus (T2DM) complicated with coronary heart disease (CHD) was explored. One hundred and fifty normal patients (normal group), 150 patients with pure T2DM (T2DM group) and 150 patients with T2DM complicated with coronary heart disease (T2DM + CHD group) were selected from Xi'an No. 5 Hospital. All the participants met our inclusion criteria. Age, body mass index, waist-to-hip ratio, blood lipid and fasting plasma glucose (FPG), of all the subjects were measured. Chemiluminescent immunoassay was adopted for the detection of FPG and double-antibody sandwich method was used for the determination of fasting plasma leptin, and assay of high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Insulin resistance index (IRI) was used to evaluate IR and enzyme-linked immunosorbent assay was adopted for the detection of von Willebrand factor (vWF) and endothelin (ET-1). Compared with the control group, patients in the T2DM + CHD group and those in the T2DM group had higher homeostasis model assessment-IR, and higher assay of plasma leptin, hs-CRP, IL-6 and TNF-α (P<0.05), and lower vascular endothelial function (P<0.05). Moreover, compared with the T2DM group, T2DM + CHD group had higher plasma leptin, and higher assay of hs-CRP, IL-6 and TNF-α (P<0.05). IRI was positively correlated with hs-CRP (r=0.521, P=0.001), IL-6 (r=0.359, P=0.001) and TNF-α (r=0.386, P=0.001), leptin was positively correlated with hs-CRP (r=0.305, P=0.001), IL-6 (r=0.259, P=0.002) and TNF-α (r=0.429, P=0.001), and IRI had no correlation with ET-1 (r=0.058, P=0.734) and vWF (r=0.047, P=0.812), that is, it had no direct correlation with vascular endothelial function. Level of leptin was positively correlated with ET-1 (r=0.366, P=0.001) and vWF (r=0.471, P=0.001), that is, it was negatively correlated with vascular endothelial function. Our results showed that leptin, hs-CRP, IL-6 and TNF-α are involved in the occurrence and development of CHD in patients with T2DM. IR has no direct correlation with the occurrence and development of CHD in patients with T2DM.
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Affiliation(s)
- Jie Zhang
- Department of Cardiology, Xi'an No. 5 Hospital, Xi'an, Shaanxi 710082, P.R. China
| | - Jing Jin
- Department of Geriatrics, Xi'an No. 5 Hospital, Xi'an, Shaanxi 710082, P.R. China
| | - Jilun Liu
- Department of Cardiology, No. 215 Hospital of Shaanxi Nuclear Industry, Xianyang, Shaanxi 712000, P.R. China
| | - Yajun He
- Department of Cardiology, No. 215 Hospital of Shaanxi Nuclear Industry, Xianyang, Shaanxi 712000, P.R. China
| | - Peng Zhang
- Department of Cardiology, The Affiliated Hospital of Yan'an University, Yan'an, Shaanxi 716000, P.R. China
| | - Wucheng Ye
- Department of Cardiology, Xingyuan Hospital of Yulin, Yulin, Shaanxi 719000, P.R. China
| | - Wei Zhu
- Department of Clinical Laboratory, The Central Hospital of Baoji, Baoji, Shaanxi 721008, P.R. China
| | - Mingliang Li
- Department of Cardiovascular Medicine, Hanzhong People's Hospital, Hanzhong, Shaanxi 723000, P.R. China
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14
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Maeda A, Uchida M, Nishikawa S, Nishino T, Konishi H. Role of N-myristoylation in stability and subcellular localization of the CLPABP protein. Biochem Biophys Res Commun 2017; 495:1249-1256. [PMID: 29180010 DOI: 10.1016/j.bbrc.2017.11.112] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 11/17/2017] [Indexed: 11/28/2022]
Abstract
Cardiolipin and phosphatidic acid-binding protein (CLPABP) controls the stability of the mRNA harboring an AU-rich element (ARE) in the 3' UTR with the help of the RNA stabilizer, human antigen R (HuR). Although CLPABP is localized on the mitochondrial surface as a large protein-RNA complex, its precise role is not yet known. Recently, CLPABP was identified as an N-myristoylated protein. Here, we demonstrate the effects of N-myristoylation on the functions of CLPABP. In the present study, compared to the wild-type protein that possessed the "MG" motif at the N-terminus for N-myristoylation, the mutant CLPABP protein that lacked N-myristoylation modification site was unstable. Furthermore, the expression of the G/A mutant of CLPABP, which lacked N-myristoylation site, induced morphological alterations in mitochondria. Because pleckstrin homology domain-deleted mutant, which was fused with the N-myristoylation site derived from intact CLPABP, could not colocalize with mitochondria, N-myristoylation of CLPABP was predicted to affect its stability onto the mitochondrial membrane rather than its subcellular localization.
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Affiliation(s)
- Akane Maeda
- Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023, Japan
| | - Moe Uchida
- Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023, Japan
| | - Sumire Nishikawa
- Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023, Japan
| | - Tasuku Nishino
- Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023, Japan
| | - Hiroaki Konishi
- Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023, Japan.
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15
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Wu Y, Lee MJ, Ido Y, Fried SK. High-fat diet-induced obesity regulates MMP3 to modulate depot- and sex-dependent adipose expansion in C57BL/6J mice. Am J Physiol Endocrinol Metab 2017; 312:E58-E71. [PMID: 27879248 PMCID: PMC5283879 DOI: 10.1152/ajpendo.00128.2016] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 10/26/2016] [Accepted: 11/08/2016] [Indexed: 12/20/2022]
Abstract
Increased adipocyte size is hypothesized to signal the recruitment of adipose progenitor cells (APCs) to expand tissue storage capacity. To investigate depot and sex differences in adipose growth, male and female C57BL/6J mice (10 wk-old) were challenged with high-fat (HF) or low-fat (LF) diets (D) for 14 wk. The HFD increased gonadal (GON) depot weight by adipocyte hypertrophy and hyperplasia in females but hypertrophy alone in males. In both sexes, inguinal (ING) adipocytes were smaller than GON, and depot expansion was due to hypertrophy. Matrix metalloproteinase 3 (Mmp3), an antiadipogenic factor, and its inhibitor Timps modulate the extracellular matrix remodeling needed for depot expansion. Mmp3 mRNA was depot different (ING > GON), higher in females than males and mainly expressed in APCs. In males, HFD-induced obesity increased tissue and APC Mmp3 mRNA levels and MMP3 protein and enzymatic activity. In females however, HFD significantly decreased MMP3 protein without affecting its mRNA levels. MMP3 activity also decreased (significant in ING). Timp4 mRNA was expressed mainly in adipocytes, and HFD-induced obesity tended to increase the ratio of TIMP4 to MMP3 protein in females, whereas it decreased it in males. Overexpression of Mmp3 in 3T3-L1 preadipocytes or rhMMP3 protein added to primary human preadipocytes inhibited differentiation, whereas rhTIMP4 improved adipogenesis and attenuated the inhibitory effect of rhMMP3. These data suggest that HFD-induced obesity downregulates APC MMP3 expression to trigger adipogenesis, and adipocyte TIMP4 may modulate this process to regulate hyperplastic vs. hypertrophic adipose tissue expansion, fat distribution, and metabolic health in a sex- and depot-dependent manner.
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Affiliation(s)
- Yuanyuan Wu
- Obesity Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts
| | - Mi-Jeong Lee
- Obesity Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts
| | - Yasuo Ido
- Obesity Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts
| | - Susan K Fried
- Obesity Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts
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16
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Burnett LC, Skowronski AA, Rausch R, LeDuc CA, Leibel RL. Determination of the half-life of circulating leptin in the mouse. Int J Obes (Lond) 2016; 41:355-359. [PMID: 28025576 PMCID: PMC5340585 DOI: 10.1038/ijo.2016.238] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/16/2016] [Accepted: 12/11/2016] [Indexed: 01/01/2023]
Abstract
Background The adipokine hormone, leptin, is a major component of body weight homeostasis. Numerous studies have been performed administering recombinant mouse leptin as an experimental reagent; however, the half life of circulating leptin following exogenous administration of recombinant mouse leptin has not been carefully evaluated. Methods Exogenous leptin was administered (3 mg leptin/kg body weight) to ten week old fasted non-obese male mice and plasma was serially collected at seven time points; plasma leptin concentration was measured by ELISA at each time point to estimate the circulating half life of mouse leptin. Results Under the physiological circumstances tested, the half life of mouse leptin was 40.2 (+/− 2.2) minutes. Circulating leptin concentrations up to one hour following exogenous leptin administration were 170-fold higher than endogenous levels at fasting. Conclusions The half life of mouse leptin was determined to be 40.2 minutes. These results should be useful in planning and interpreting experiments employing exogenous leptin. The unphysiological elevations in circulating leptin resulting from widely used dosing regimens for exogenous leptin are likely to confound inferences regarding some aspects of the hormone’s clinical biology.
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Affiliation(s)
- L C Burnett
- Columbia University Institute of Human Nutrition, New York, NY, USA.,Columbia University Department of Pediatrics, Division of Molecular Genetics, New York, NY, USA.,Naomi Berrie Diabetes Center, New York, NY, USA
| | - A A Skowronski
- Columbia University Institute of Human Nutrition, New York, NY, USA.,Columbia University Department of Pediatrics, Division of Molecular Genetics, New York, NY, USA.,Naomi Berrie Diabetes Center, New York, NY, USA
| | - R Rausch
- Columbia University Department of Pediatrics, Division of Molecular Genetics, New York, NY, USA.,Naomi Berrie Diabetes Center, New York, NY, USA
| | - C A LeDuc
- Columbia University Department of Pediatrics, Division of Molecular Genetics, New York, NY, USA.,Naomi Berrie Diabetes Center, New York, NY, USA.,New York Obesity Research Center, New York, NY, USA
| | - R L Leibel
- Columbia University Department of Pediatrics, Division of Molecular Genetics, New York, NY, USA.,Naomi Berrie Diabetes Center, New York, NY, USA.,New York Obesity Research Center, New York, NY, USA
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Nishino T, Matsunaga R, Jikihara H, Uchida M, Maeda A, Qi G, Abe T, Kiyonari H, Tashiro S, Inagaki-Ohara K, Shimamoto F, Konishi H. Antagonizing effect of CLPABP on the function of HuR as a regulator of ARE-containing leptin mRNA stability and the effect of its depletion on obesity in old male mouse. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1816-1827. [PMID: 27616329 DOI: 10.1016/j.bbalip.2016.09.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 09/05/2016] [Accepted: 09/07/2016] [Indexed: 01/10/2023]
Abstract
Cardiolipin and phosphatidic acid-binding protein (CLPABP) is a pleckstrin homology domain-containing protein and is localized on the surface of mitochondria of cultured cells as a large protein-RNA complex. To analyze the physiological functions of CLPABP, we established and characterized a CLPABP knockout (KO) mouse. Although expression levels of CLPABP transcripts in the developmental organs were high, CLPABP KO mice were normal at birth and grew normally when young. However, old male mice presented a fatty phenotype, similar to that seen in metabolic syndrome, in parallel with elevated male- and age-dependent CLPABP gene expression. One of the reasons for this obesity in CLPABP KO mice is dependence on increases in leptin concentration in plasma. The leptin transcripts were also upregulated in the adipose tissue of KO mice compared with wild-type (WT) mice. To understand the difference in levels of the transcriptional product, we focused on the effect of CLPABP on the stability of mRNA involving an AU-rich element (ARE) in its 3'UTR dependence on the RNA stabilizer, human antigen R (HuR), which is one of the CLPABP-binding proteins. Increase in stability of ARE-containing mRNAs of leptin by HuR was antagonized by the expression of CLPABP in cultured cells. Depletion of CLPABP disturbed the normal subcellular localization of HuR to stress granules, and overexpression of CLPABP induced instability of leptin mRNA by inhibiting HuR function. Consequently, leptin levels in old male mice might be regulated by CLPABP expression, which might lead to body weight control.
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Affiliation(s)
- Tasuku Nishino
- Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023, Japan
| | - Ryota Matsunaga
- Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023, Japan
| | - Hiroshi Jikihara
- Department of Health Science, Prefectural University of Hiroshima, Hiroshima 734-8558, Japan
| | - Moe Uchida
- Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023, Japan
| | - Akane Maeda
- Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023, Japan
| | - Guangying Qi
- Department of Health Science, Prefectural University of Hiroshima, Hiroshima 734-8558, Japan
| | - Takaya Abe
- Genetic Engineering Team, RIKEN Center for Life Science Technologies, 2-2-3 Minatojima Minami-machi,Chuou-ku, Kobe 650-0047, Japan
| | - Hiroshi Kiyonari
- Animal Resource Development Unit, RIKEN Center for Life Science Technologies, 2-2-3 Minatojima Minami-machi, Chuou-ku, Kobe 650-0047, Japan; Genetic Engineering Team, RIKEN Center for Life Science Technologies, 2-2-3 Minatojima Minami-machi,Chuou-ku, Kobe 650-0047, Japan
| | - Satoshi Tashiro
- Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553, Japan
| | - Kyoko Inagaki-Ohara
- Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023, Japan
| | - Fumio Shimamoto
- Department of Health Science, Prefectural University of Hiroshima, Hiroshima 734-8558, Japan
| | - Hiroaki Konishi
- Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023, Japan.
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18
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Padilla K, Gonzalez-Mendoza D, Berumen LC, Escobar JE, Miledi R, García-Alcocer G. Differential gene expression patterns and colocalization of ATP-gated P2X6/P2X4 ion channels during rat small intestine ontogeny. Gene Expr Patterns 2016; 21:81-8. [PMID: 27545450 DOI: 10.1016/j.gep.2016.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 08/03/2016] [Accepted: 08/09/2016] [Indexed: 11/29/2022]
Abstract
Gene coding for ATP-gated receptor ion channels (P2X1-7) has been associated with the developmental process in various tissues; among these ion channel subtypes, P2X6 acts as a physiological regulator of P2X4 receptor functions when the two receptors form heteroreceptors. The P2X4 receptor is involved in pain sensation, the inflammatory process, and body homeostasis by means of Mg(2+) absorption through the intestine. The small intestine is responsible for the absorption and digestion of nutrients; throughout its development, several gene expressions are induced that are related to nutrients received, metabolism, and other intestine functions. Previous work has shown a differential P2X4 and P2X6 protein distribution in the small intestine of newborn and adult rats; however, it is not well-known at what age the change in the relationship between the gene and protein expression occurs and whether or not these receptors are colocalized. In this work, we evaluate P2X4 and P2X6 gene expression patterns by qPCR from embryonic (E18, P0, P7, P17, P30) to adult age in rat gut, as well as P2X6/P2X4 colocalization using qRT-PCR and confocal immunofluorescence in proximal and distal small intestine sections. The results showed that P2X6 and P2X4 gene expression levels of both receptors decreased at the embryonic-perinatal transition, whereas from ages P17 to P30 (suckling-weaning transition) both receptors increased their gene expression levels. Furthermore, P2X4 and P2X6 proteins were expressed in a different way during rat small intestine development, showing a higher colocalization coefficient at age P30 in both intestine regions. Those results suggest that purinergic receptors may play a role in intestinal maturation, which is associated with age and intestinal region.
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Affiliation(s)
- Karla Padilla
- Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico.
| | - David Gonzalez-Mendoza
- Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico.
| | - Laura C Berumen
- Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico.
| | - Jesica E Escobar
- Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico.
| | - Ricardo Miledi
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Blvd Juriquilla 3001, Juriquilla, Querétaro 76230, Mexico.
| | - Guadulupe García-Alcocer
- Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico.
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Lee MJ, Yang RZ, Karastergiou K, Smith SR, Chang JR, Gong DW, Fried SK. Low expression of the GILZ may contribute to adipose inflammation and altered adipokine production in human obesity. J Lipid Res 2016; 57:1256-63. [PMID: 27178044 DOI: 10.1194/jlr.m067728] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Indexed: 12/30/2022] Open
Abstract
The glucocorticoid-induced leucine zipper (GILZ), a primary target of glucocorticoids, is expressed in human adipocytes, but its importance in adipocyte function is unknown. Because TNFα is increased in obese adipose tissue and antagonizes a number of glucocorticoid actions, we investigated the interplay of these pathways. GILZ knockdown increased and GILZ overexpression decreased interleukin-6 (IL-6) and leptin mRNA and protein secretion. GILZ knockdown increased the magnitude of the glucocorticoid effect on leptin secretion, but did not affect the glucocorticoid suppression of IL-6. Although GILZ silencing decreased adiponectin mRNA levels, it did not affect the amount of adiponectin secreted. GILZ negatively modulated pro-inflammatory signaling pathways, blocking basal and TNFα-stimulated (1 h) p65 nuclear factor κB nuclear translocation and transcriptional activity by binding to p65 in the cytoplasm. GILZ silencing increased basal ERK1/2 and JNK phosphorylation, and decreased MAPK phosphatase-1 protein levels. Longer term TNFα (4 h or 24 h) treatment decreased GILZ expression in human adipocytes. Furthermore, adipose tissue GILZ mRNA levels were reduced in proportion to the degree of obesity and expression of inflammatory markers. Overall, these results suggest that GILZ antagonizes the pro-inflammatory effects of TNFα in human adipocytes, and its downregulation in obesity may contribute to adipose inflammation and dysregulated adipokine production, and thereby systemic metabolism.
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Affiliation(s)
- Mi-Jeong Lee
- Obesity Research Center, Section of Endocrinology, Diabetes, and Nutrition, School of Medicine, Boston University, Boston, MA 02118 School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Rong-Ze Yang
- Department of Endocrinology, Diabetes, and Nutrition, School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Kalypso Karastergiou
- Obesity Research Center, Section of Endocrinology, Diabetes, and Nutrition, School of Medicine, Boston University, Boston, MA 02118 School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Steven R Smith
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL 32804
| | - Jeffery R Chang
- Division of Reproductive Endocrinology, School of Medicine, University of California, San Diego, San Diego, CA 92093
| | - Da-Wei Gong
- Department of Endocrinology, Diabetes, and Nutrition, School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Susan K Fried
- Obesity Research Center, Section of Endocrinology, Diabetes, and Nutrition, School of Medicine, Boston University, Boston, MA 02118 School of Medicine, University of Maryland, Baltimore, MD 21201
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20
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García-Cáceres C, Fuente-Martín E, Díaz F, Granado M, Argente-Arizón P, Frago LM, Freire-Regatillo A, Barrios V, Argente J, Chowen JA. The opposing effects of ghrelin on hypothalamic and systemic inflammatory processes are modulated by its acylation status and food intake in male rats. Endocrinology 2014; 155:2868-80. [PMID: 24848869 DOI: 10.1210/en.2014-1074] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Ghrelin is an endogenous hormone that stimulates appetite and adipose tissue accrual. Both the acylated (AG) and non-acylated (DAG) isoforms of this hormone are also reported to exert anti-inflammatory and protective effects systemically and in the central nervous system. As inflammatory processes have been implicated in obesity-associated secondary complications, we hypothesized that this natural appetite stimulator may protect against negative consequences resulting from excessive food intake. Adult male Wistar rats were treated icv (5 μg/day) with AG, DAG, the ghrelin mimetic GH-releasing peptide (GHRP)-6, AG, and pair-fed with controls (AG-pf) or saline for 14 days. Regardless of food intake AG increased visceral adipose tissue (VAT) and decreased circulating cytokine levels. However, AG reduced cytokine production in VAT only in rats fed ad libitum. Hypothalamic cytokine production was increased in AG-treated rats fed ad libitum and by DAG, but intracellular inflammatory signaling pathways associated with insulin and leptin resistance were unaffected. Gliosis was not observed in response to any treatment as glial markers were either reduced or unaffected. AG, DAG, and GHRP-6 stimulated production of hypothalamic insulin like-growth factor I that is involved in cell protective mechanisms. In hypothalamic astrocyte cell cultures AG decreased tumor necrosis factorα and DAG decreased interleukin-1β mRNA levels, suggesting direct anti-inflammatory effects on astrocytes. Thus, whereas ghrelin stimulates food intake and weight gain, it may also induce mechanisms of cell protection that help to detour or delay systemic inflammatory responses and hypothalamic gliosis due to excess weight gain, as well as its associated pathologies.
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Affiliation(s)
- Cristina García-Cáceres
- Hospital Infantil Universitario Niño Jesús, Department of Endocrinology, Instituto de Investigación La Princesa, Universidad Autónoma de Madrid and Centro de Investigación Biomédica en Red (CIBER) de la Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, 28009 Madrid, Spain
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Yonekura S, Hirota S, Tokutake Y, Rose MT, Katoh K, Aso H. Dexamethasone and acetate modulate cytoplasmic leptin in bovine preadipocytes. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2014; 27:567-73. [PMID: 25049989 PMCID: PMC4093523 DOI: 10.5713/ajas.2013.13559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 12/26/2013] [Accepted: 12/10/2013] [Indexed: 11/27/2022]
Abstract
Hormonal and nutrient signals regulate leptin synthesis and secretion. In rodents, leptin is stored in cytosolic pools of adipocytes. However, not much information is available regarding the regulation of intracellular leptin in ruminants. Recently, we demonstrated that leptin mRNA was expressed in bovine intramuscular preadipocyte cells (BIP cells) and that a cytoplasmic leptin pool may be present in preadipocytes. In the present study, we investigated the expression of cytoplasmic leptin protein in BIP cells during differentiation as well as the effects of various factors added to the differentiation medium on its expression in BIP cells. Leptin mRNA expression was observed only at 6 and 8 days after adipogenic induction, whereas the cytoplasmic leptin concentration was the highest on day 0 and decreased gradually thereafter. Cytoplasmic leptin was detected at 6 and 8 days after adipogenic induction, but not at 4 days after adipogenic induction. The cytoplasmic leptin concentration was reduced in BIP cells at 4 days after treatment with dexamethasone, whereas cytoplasmic leptin was not observed at 8 days after treatment. In contrast, acetate significantly enhanced the cytoplasmic leptin concentration in BIP cells at 8 days after treatment, although acetate alone did not induce adipocyte differentiation in BIP cells. These results suggest that dexamethasone and acetate modulate the cytoplasmic leptin concentration in bovine preadipocytes.
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Affiliation(s)
- Shinichi Yonekura
- Institute of Rural Studies, University of Wales, Aberystwyth, Ceredigion SY23 3AL, UK
| | - Shohei Hirota
- Institute of Rural Studies, University of Wales, Aberystwyth, Ceredigion SY23 3AL, UK
| | - Yukako Tokutake
- Institute of Rural Studies, University of Wales, Aberystwyth, Ceredigion SY23 3AL, UK
| | - Michael T Rose
- Institute of Rural Studies, University of Wales, Aberystwyth, Ceredigion SY23 3AL, UK
| | - Kazuo Katoh
- Department of Animal Physiology, Graduate School of Agriculture, Tohoku University, Amamiyamachi, Sendai 981-8555, Japan
| | - Hisashi Aso
- Department of Cellular Biology, Graduate School of Agriculture, Tohoku University, Amamiyamachi, Sendai 981-8555, Japan
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Bernardi JR, Ferreira CF, Senter G, Krolow R, de Aguiar BW, Portella AK, Kauer-Sant'Anna M, Kapczinski F, Dalmaz C, Goldani MZ, Silveira PP. Early life stress interacts with the diet deficiency of omega-3 fatty acids during the life course increasing the metabolic vulnerability in adult rats. PLoS One 2013; 8:e62031. [PMID: 23614006 PMCID: PMC3629088 DOI: 10.1371/journal.pone.0062031] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 03/16/2013] [Indexed: 12/19/2022] Open
Abstract
Early stress can cause metabolic disorders in adulthood. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) deficiency has also been linked to the development of metabolic disorders. The aim of this study was to assess whether an early stressful event such as maternal separation interacts with the nutritional availability of n-3 PUFAs during the life course on metabolic aspects. Litters were randomized into: maternal separated (MS) and non-handled (NH). The MS group was removed from their dam for 3 hours per day and put in an incubator at 32°C on days 1° to 10° postnatal (PND). On PND 35, males were subdivided into diets that were adequate or deficient in n-3 PUFAs, and this intervention was applied during the subsequent 15 weeks. Animal's body weight and food consumption were measured weekly, and at the end of the treatment tissues were collected. MS was associated with increased food intake (p = 0.047) and weight gain (p = 0.012), but no differences were found in the NPY hypothalamic content between the groups. MS rats had also increased deposition of abdominal fat (p<0.001) and plasma triglycerides (p = 0.018) when compared to the NH group. Interactions between early life stress and n-3 PUFAs deficiency were found in plasma insulin (p = 0.033), HOMA index (p = 0.049), leptin (p = 0.010) and liver PEPCK expression (p = 0.050), in which the metabolic vulnerability in the MS group was aggravated by the n-3 PUFAs deficient diet exposure. This was associated with specific alterations in the peripheral fatty acid profile. Variations in the neonatal environment interact with nutritional aspects during the life course, such as n-3 PUFAs diet content, and persistently alter the metabolic vulnerability in adulthood.
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Affiliation(s)
- Juliana R. Bernardi
- Núcleo de Estudos da Saúde da Criança e do Adolescente (NESCA), Hospital de Clínicas de Porto Alegre (HCPA), Faculdade de Medicina, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Charles F. Ferreira
- Núcleo de Estudos da Saúde da Criança e do Adolescente (NESCA), Hospital de Clínicas de Porto Alegre (HCPA), Faculdade de Medicina, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Gabrielle Senter
- Núcleo de Estudos da Saúde da Criança e do Adolescente (NESCA), Hospital de Clínicas de Porto Alegre (HCPA), Faculdade de Medicina, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Rachel Krolow
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Bianca W. de Aguiar
- Bipolar Disorders Program and INCT Translational Medicine (CNPq), Hospital de Clínicas de Porto Alegre (HCPA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - André K. Portella
- Núcleo de Estudos da Saúde da Criança e do Adolescente (NESCA), Hospital de Clínicas de Porto Alegre (HCPA), Faculdade de Medicina, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Márcia Kauer-Sant'Anna
- Bipolar Disorders Program and INCT Translational Medicine (CNPq), Hospital de Clínicas de Porto Alegre (HCPA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Flávio Kapczinski
- Bipolar Disorders Program and INCT Translational Medicine (CNPq), Hospital de Clínicas de Porto Alegre (HCPA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Carla Dalmaz
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Marcelo Z. Goldani
- Núcleo de Estudos da Saúde da Criança e do Adolescente (NESCA), Hospital de Clínicas de Porto Alegre (HCPA), Faculdade de Medicina, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Patrícia P. Silveira
- Núcleo de Estudos da Saúde da Criança e do Adolescente (NESCA), Hospital de Clínicas de Porto Alegre (HCPA), Faculdade de Medicina, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
- * E-mail:
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Abstract
The adipocyte enlargement is associated with an increase in the cytoplasmic lipid content, but how the plasma membrane area follows this increase is poorly understood. We monitored single-cell membrane surface area fluctuations, which mirror the dynamics of exocytosis and endocytosis. We employed the patch-clamp technique to measure membrane capacitance (C(m)), a parameter linearly related to the plasma membrane area. Specifically, we studied whether insulin affects membrane area dynamics in adipocytes. A five-minute cell exposure to insulin increased resting C(m) by 12 ± 4%; in controls the change in C(m) was not different from zero. We measured cell diameter of isolated rat adipocytes microscopically. Twenty-four hour exposure of cells to insulin resulted in a significant increase in cell diameter by 5.1 ± 0.6%. We conclude that insulin induces membrane area increase, which may in chronic hyperinsulinemia promote the enlargement of plasma membrane area, acting in concert with other insulin-mediated metabolic effects on adipocytes.
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Affiliation(s)
- H H Chowdhury
- Laboratory of Neuroendocrinology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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Sjögren P, Sierra-Johnson J, Kallings LV, Cederholm T, Kolak M, Halldin M, Brismar K, de Faire U, Hellénius ML, Fisher RM. Functional changes in adipose tissue in a randomised controlled trial of physical activity. Lipids Health Dis 2012; 11:80. [PMID: 22721353 PMCID: PMC3475078 DOI: 10.1186/1476-511x-11-80] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 06/09/2012] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND A sedentary lifestyle predisposes to cardiometabolic diseases. Lifestyle changes such as increased physical activity improve a range of cardiometabolic risk factors. The objective of this study was to examine whether functional changes in adipose tissue were related to these improvements. METHODS Seventy-three sedentary, overweight (mean BMI 29.9 ± 3.2 kg/m2) and abdominally obese, but otherwise healthy men and women (67.6 ± 0.5 years) from a randomised controlled trial of physical activity on prescription over a 6-month period were included (control n = 43, intervention n = 30). Detailed examinations were carried out at baseline and at follow-up, including fasting blood samples, a comprehensive questionnaire and subcutaneous adipose tissue biopsies for fatty acid composition analysis (n = 73) and quantification of mRNA expression levels of 13 candidate genes (n = 51), including adiponectin, leptin and inflammatory cytokines. RESULTS At follow-up, the intervention group had a greater increase in exercise time (+137 min/week) and a greater decrease in body fat mass (-1.5 kg) compared to the control subjects (changes of 0 min/week and -0.5 kg respectively). Circulating concentrations of adiponectin were unchanged, but those of leptin decreased significantly more in the intervention group (-1.8 vs -1.1 ng/mL for intervention vs control, P < 0.05). The w6-polyunsaturated fatty acid content, in particular linoleic acid (18:2w6), of adipose tissue increased significantly more in the intervention group, but the magnitude of the change was small (+0.17 vs +0.02 percentage points for intervention vs control, P < 0.05). Surprisingly leptin mRNA levels in adipose tissue increased in the intervention group (+107% intervention vs -20% control, P < 0.05), but changes in expression of the remaining genes did not differ between the groups. CONCLUSIONS After a 6-month period of increased physical activity in overweight elderly individuals, circulating leptin concentrations decreased despite increased levels of leptin mRNA in adipose tissue. Otherwise, only minor changes occurred in adipose tissue, although several improvements in metabolic parameters accompanied the modest increase in physical activity.
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Affiliation(s)
- Per Sjögren
- Atherosclerosis Research Unit,, Department of Medicine, (Solna) Karolinska Institutet,, Stockholm, Sweden
- Clinical Nutrition and Metabolism, Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Justo Sierra-Johnson
- Atherosclerosis Research Unit,, Department of Medicine, (Solna) Karolinska Institutet,, Stockholm, Sweden
- Cardiovascular Division, Mayo Clinic, Rochester, MN, USA
| | - Lena V Kallings
- Department of Sport and Health Sciences, Swedish School of Sport and Health Sciences, Stockholm, Sweden
- Unit of Cardiology, Department of Medicine, (Solna) Karolinska Institutet, Stockholm, Sweden
| | - Tommy Cederholm
- Clinical Nutrition and Metabolism, Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Maria Kolak
- Atherosclerosis Research Unit,, Department of Medicine, (Solna) Karolinska Institutet,, Stockholm, Sweden
| | - Mats Halldin
- Institute of Environmental Medicine, Division of Cardiovascular Epidemiology, Karolinska Institutet, Stockholm, Sweden
| | - Kerstin Brismar
- Rolf Luft Research Center for Diabetes and Endocrinology, , Department of Molecular Medicine and Surgery, Karolinska Institutet, , Stockholm, Sweden
| | - Ulf de Faire
- Institute of Environmental Medicine, Division of Cardiovascular Epidemiology, Karolinska Institutet, Stockholm, Sweden
| | - Mai-Lis Hellénius
- Unit of Cardiology, Department of Medicine, (Solna) Karolinska Institutet, Stockholm, Sweden
| | - Rachel M Fisher
- Atherosclerosis Research Unit,, Department of Medicine, (Solna) Karolinska Institutet,, Stockholm, Sweden
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Chmurzynska A, Stachowiak M, Pruszynska-Oszmalek E. Maternal protein and folic acid intake during gestation does not program leptin transcription or serum concentration in rat progeny. GENES AND NUTRITION 2011; 7:217-22. [PMID: 21735287 PMCID: PMC3316755 DOI: 10.1007/s12263-011-0239-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 06/25/2011] [Indexed: 12/19/2022]
Abstract
Maternal nutrition during gestation influences the development of the fetus, thereby determining its phenotype, including nutrient metabolism, appetite, and feeding behavior. The control of appetite is a very complex process and can be modulated by orexigenic and anorexigenic mediators such as leptin, which is involved in the regulation of energy homeostasis by controlling food intake and energy expenditure. Leptin transcription and secretion are regulated by numerous factors, nutrition being one of them. The present study was designed to test whether maternal nutrition can permanently affect leptin gene transcription and leptin serum concentration in rat progeny. Moreover, we analyzed whether leptin expression and secretion in response to high-fat postweaning feeding depends on the maternal diet during gestation. Pregnant rats were fed either a normal protein, normal folic acid diet (the AIN-93 diet); a protein-restricted, normal folic acid diet; a protein-restricted, folic acid-supplemented diet; or a normal protein, folic acid-supplemented diet. After weaning, the progeny was fed either the AIN-93 diet or a high-fat diet. Neither maternal nutrition nor the postweaning diet significantly affected Lep transcription. High-fat feeding after weaning was associated with higher serum leptin concentration, but the reaction of an organism to the fat content of the diet was not determined by maternal nutrition during gestation. There was no correlation between Lep mRNA level and serum leptin concentration. Global DNA methylation in adipose tissue was about 30% higher in rats fed postnatally the high-fat diet (P < 0.01). Our study showed that the protein and folic acid content in the maternal diet had no significant programming effect on Lep transcription and serum leptin concentration in the rats.
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Affiliation(s)
- Agata Chmurzynska
- Department of Human Nutrition and Hygiene, Poznań University of Life Sciences, Wojska Polskiego 31, 60-624, Poznań, Poland,
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26
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The molecular mechanism of leptin secretion and expression induced by aristolochic acid in kidney fibroblast. PLoS One 2011; 6:e16654. [PMID: 21304902 PMCID: PMC3033396 DOI: 10.1371/journal.pone.0016654] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 01/05/2011] [Indexed: 12/17/2022] Open
Abstract
Background Leptin is a peptide hormone playing pivotal role in regulating food intake and energy expenditure. Growing evidence has suggested the pro-inflammatory and fibrogenic properties of leptin. In addition, patients with renal fibrosis have higher level of plasma leptin, which was due to the increased leptin production. Aristolochic acid (AA) is a botanical toxin characterized to associate with the development of renal fibrosis including tubulointerstitial fibrosis. However, whether leptin is upregulated to participate in AA-induced kidney fibrosis remain completely unknown. Methodology/Principal Findings In this study, leptin expression was increased by sublethal dose of AA in kidney fibroblast NRK49f determined by enzyme-linked immunosorbent assay and Western blot. Data from real-time reverse transcriptase-polymerase chain reaction revealed that leptin was upregulated by AA at transcriptional level. DNA binding activity of CCAAT enhancer binding protein α (C/EBP α), one of the transcription factors for leptin gene, was enhanced in DNA affinity precipitation assay and chromatin immunoprecipitation experiments. Knockdown of C/EBP α expression by small interfering RNA markedly reduced AA-induced leptin expression. Moreover, AA promoted Akt interaction with p-PDK1, and increased phosphorylated activation of Akt. Akt knockdown, and inhibition of Akt signaling by LY294002 and mTOR inhibitor rapamycin reduced leptin expression. Furthermore, treatment of LY294002 or rapamycin significantly suppressed AA-induced C/EBP α DNA-binding activity. These results suggest that Akt and C/EBP α activation were involved in AA-regulated leptin expression. Conclusions/Significance Our findings demonstrate the first that AA could induce secretion and expression of fibrogenic leptin in kidney fibroblasts, which reveal potential involvement of leptin in the progression of kidney fibrosis in aristolochic acid nephropathy.
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27
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Frigolet ME, Torres N, Uribe-Figueroa L, Rangel C, Jimenez-Sanchez G, Tovar AR. White adipose tissue genome wide-expression profiling and adipocyte metabolic functions after soy protein consumption in rats. J Nutr Biochem 2010; 22:118-29. [PMID: 20471815 DOI: 10.1016/j.jnutbio.2009.12.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 11/27/2009] [Accepted: 12/10/2009] [Indexed: 12/14/2022]
Abstract
Obesity is associated with an increase in adipose tissue mass due to an imbalance between high dietary energy intake and low physical activity; however, the type of dietary protein may contribute to its development. The aim of the present work was to study the effect of soy protein versus casein on white adipose tissue genome profiling, and the metabolic functions of adipocytes in rats with diet-induced obesity. The results showed that rats fed a Soy Protein High-Fat (Soy HF) diet gained less weight and had lower serum leptin concentration than rats fed a Casein High-Fat (Cas HF) diet, despite similar energy intake. Histological studies indicated that rats fed the Soy HF diet had significantly smaller adipocytes than those fed the Cas HF diet, and this was associated with a lower triglyceride/DNA content. Fatty acid synthesis in isolated adipocytes was reduced by the amount of fat consumed but not by the type of protein ingested. Expression of genes of fatty acid oxidation increased in adipose tissue of rats fed Soy diets; microarray analysis revealed that Soy protein consumption modified the expression of 90 genes involved in metabolic functions and inflammatory response in adipose tissue. Network analysis showed that the expression of leptin was regulated by the type of dietary protein and it was identified as a central regulator of the expression of lipid metabolism genes in adipose tissue. Thus, soy maintains the size and metabolic functions of adipose tissue through biochemical adaptations, adipokine secretion, and global changes in gene expression.
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Affiliation(s)
- Maria E Frigolet
- Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, DF 14000, México
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28
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Lee MJ, Fried SK. Integration of hormonal and nutrient signals that regulate leptin synthesis and secretion. Am J Physiol Endocrinol Metab 2009; 296:E1230-8. [PMID: 19318513 PMCID: PMC2692400 DOI: 10.1152/ajpendo.90927.2008] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This review summarizes recent advances in our understanding of the pre- and posttranscriptional mechanisms that regulate leptin production and secretion in adipocytes. Basal leptin production is proportional to the status of energy stores, i.e., fat cell size, and this is mainly regulated by alterations in leptin mRNA levels. Leptin mRNA levels are regulated by hormones, including glucocorticoids and catecholamines, but little is known about the transcriptional mechanisms involved. Leptin synthesis and secretion is also acutely modulated in response to hormones such as insulin and the availability of metabolic fuels. Acute variations in leptin production over a time course of minutes to hours are mediated at the levels of both translation and secretion. Increases in amino acids and insulin after a meal activate the mammalian target of rapamycin (mTOR) pathway, leading to an increase in specific rates of leptin biosynthesis. Cross-talk among mTOR, PKA, and AMP-activated protein kinase pathways appears to integrate hormonal and nutrient signals that regulate leptin mRNA translation, at least in part through mechanisms involving its 5'- and 3'-untranslated regions. In addition, the rate of leptin secretion from preformed stores in response to hormonal cues is also regulated. Insulin stimulates, and adrenergic agonists inhibit, leptin secretion, and this likely contributes to variations in the magnitude of nutrition-related leptin excursions and oscillations. Overall, the study of leptin production has contributed to a deepening understanding of leptin biology and, more broadly, to our understanding of the cellular and molecular mechanisms by which the adipocyte integrates hormonal and nutrient signals to regulate adipokine production.
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Affiliation(s)
- Mi-Jeong Lee
- Division of Endocrinology, Diabetes, and Nutrition, Department of Medicine, University of Maryland, School of Medicine, Baltimore, MD, USA
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29
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Banga A, Unal R, Tripathi P, Pokrovskaya I, Owens RJ, Kern PA, Ranganathan G. Adiponectin translation is increased by the PPARgamma agonists pioglitazone and omega-3 fatty acids. Am J Physiol Endocrinol Metab 2009; 296:E480-9. [PMID: 19088251 PMCID: PMC2660148 DOI: 10.1152/ajpendo.90892.2008] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adiponectin, made exclusively by adipocytes, is a 30-kDa secretory protein assembled posttranslationally into low-molecular weight, middle-molecular weight, and high-molecular weight homo-oligomers. PPARgamma ligand thiozolidinediones, which are widely used in the treatment of type II diabetes, increase adiponectin levels. PPARgamma also has several putative ligands that include fatty acid derivatives. Overnight treatment of rat adipocytes with pioglitazone, docosahexaenoic acid (DHA), or eicosapentaenoic acid (EPA) triggered a twofold increase in the synthesis and secretion of HMW adiponectin, and this increase was blocked by the addition of PPARgamma inhibitor GW-9662. Inhibition of glycosylation using 2,2'-dipyridyl decreased the synthesis of high-molecular weight adiponectin by pioglitazone, EPA, and DHA, but there was increased secretion of trimeric adiponectin resulting from increased translation. Although pioglitazone, DHA, and EPA increased adiponectin synthesis by more than 60%, there was no increase in total protein synthesis and no corresponding change in adiponectin mRNA expression, indicating the upregulation of translation. We examined the possibility of transacting factors in the cytoplasmic extracts from adipocytes treated with pioglitazone or DHA. In vitro translation of adiponectin mRNA was inhibited by S-100 fraction of control adipocytes and increased by S-100 extracts from adipocytes treated with pioglitazone or DHA. Consistent with this observation, both pioglitazone and DHA treatments increased the association of adiponectin mRNA with the heavier polysome fractions. Together, these data suggest that pioglitazone and the fish oils DHA or EPA are PPARgamma agonists in adipocytes with regard to adiponectin expression, and the predominant mode of adiponectin stimulation is via an increase in translation.
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Affiliation(s)
- Anannya Banga
- The Central Arkansas Veterans Healthcare System, Little Rock, AR 72205, USA
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30
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Fujimoto T, Miyasaka K, Koyanagi M, Tsunoda T, Baba I, Doi K, Ohta M, Kato N, Sasazuki T, Shirasawa S. Altered energy homeostasis and resistance to diet-induced obesity in KRAP-deficient mice. PLoS One 2009; 4:e4240. [PMID: 19156225 PMCID: PMC2627767 DOI: 10.1371/journal.pone.0004240] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Accepted: 12/10/2008] [Indexed: 11/19/2022] Open
Abstract
Obesity and related metabolic disorders have become leading causes of adult morbidity and mortality. KRAP (Ki-ras-induced actin-interacting protein) is a cytoskeleton-associated protein and a ubiquitous protein among tissues, originally identified as a cancer-related molecule, however, its physiological roles remain unknown. Here we demonstrate that KRAP-deficient (KRAP(-/-)) mice show enhanced metabolic rate, decreased adiposity, improved glucose tolerance, hypoinsulinemia and hypoleptinemia. KRAP(-/-) mice are also protected against high-fat diet-induced obesity and insulin resistance despite of hyperphagia. Notably, glucose uptake in the brown adipose tissue (BAT) in KRAP(-/-) mice is enhanced in an insulin-independent manner, suggesting that BAT is involved in altered energy homeostasis in KRAP(-/-) mice, although UCP (Uncoupling protein) expressions are not altered. Of interest is the down-regulation of fatty acid metabolism-related molecules, including acetyl-CoA carboxylase (ACC)-1, ACC-2 and fatty acid synthase in the liver of KRAP(-/-) mice, which could in part account for the metabolic phenotype in KRAP(-/-) mice. Thus, KRAP is a novel regulator in whole-body energy homeostasis and may be a therapeutic target in obesity and related diseases.
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Affiliation(s)
- Takahiro Fujimoto
- Department of Cell Biology, Faculty of Medicine, Fukuoka University, Jonan-ku, Fukuoka, Japan
- Center for Advanced Molecular Medicine, Fukuoka University, Jonan-ku, Fukuoka, Japan
| | - Kyoko Miyasaka
- Department of Clinical Physiology, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Midori Koyanagi
- Department of Cell Biology, Faculty of Medicine, Fukuoka University, Jonan-ku, Fukuoka, Japan
- Center for Advanced Molecular Medicine, Fukuoka University, Jonan-ku, Fukuoka, Japan
| | - Toshiyuki Tsunoda
- Department of Cell Biology, Faculty of Medicine, Fukuoka University, Jonan-ku, Fukuoka, Japan
- Center for Advanced Molecular Medicine, Fukuoka University, Jonan-ku, Fukuoka, Japan
| | - Iwai Baba
- Department of Cell Biology, Faculty of Medicine, Fukuoka University, Jonan-ku, Fukuoka, Japan
| | - Keiko Doi
- Department of Cell Biology, Faculty of Medicine, Fukuoka University, Jonan-ku, Fukuoka, Japan
- Center for Advanced Molecular Medicine, Fukuoka University, Jonan-ku, Fukuoka, Japan
| | - Minoru Ohta
- Department of Clinical Physiology, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Norihiro Kato
- Department of Gene Diagnostics and Therapeutics, Research Institute, International Medical Center of Japan, Shinjuku-ku, Tokyo, Japan
| | - Takehiko Sasazuki
- Department of Gene Diagnostics and Therapeutics, Research Institute, International Medical Center of Japan, Shinjuku-ku, Tokyo, Japan
| | - Senji Shirasawa
- Department of Cell Biology, Faculty of Medicine, Fukuoka University, Jonan-ku, Fukuoka, Japan
- Center for Advanced Molecular Medicine, Fukuoka University, Jonan-ku, Fukuoka, Japan
- * E-mail:
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Campbell KL, Makar KW, Kratz M, Foster-Schubert KE, McTiernan A, Ulrich CM. A pilot study of sampling subcutaneous adipose tissue to examine biomarkers of cancer risk. Cancer Prev Res (Phila) 2009; 2:37-42. [PMID: 19139016 PMCID: PMC2785801 DOI: 10.1158/1940-6207.capr-08-0073] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Examination of adipose tissue biology may provide important insight into mechanistic links for the observed association between higher body fat and risk of several types of cancer, in particular colorectal and breast cancer. We tested two different methods of obtaining adipose tissue from healthy individuals. Ten overweight or obese (body mass index, 25-40 kg/m(2)), postmenopausal women were recruited. Two subcutaneous abdominal adipose tissue samples were obtained per individual (i.e., right and left lower abdominal regions) using two distinct methods (method A: 14-gauge needle with incision, versus method B: 16-gauge needle without incision). Gene expression was examined at the mRNA level for leptin, adiponectin, aromatase, interleukin 6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) in flash-frozen tissue, and at the protein level for leptin, adiponectin, IL-6, and TNF-alpha following short-term culture. Participants preferred biopsy method A and few participants reported any of the usual minor side effects. Gene expression was detectable for leptin, adiponectin, and aromatase, but was below detectable limits for IL-6 and TNF-alpha. For detectable genes, relative gene expression in adipose tissue obtained by methods A and B was similar for adiponectin (r = 0.64, P = 0.06) and leptin (r = 0.80, P = 0.01), but not for aromatase (r = 0.37,P = 0.34). Protein levels in tissue culture supernatant exhibited good intra-assay agreement [coefficient of variation (CV), 1-10%], with less agreement for intraindividual agreement (CV, 17-29%) and reproducibility, following one freeze-thaw cycle (CV, >14%). Subcutaneous adipose tissue biopsies from healthy, overweight individuals provide adequate amounts for RNA extraction, gene expression, and other assays of relevance to cancer prevention research.
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Affiliation(s)
- Kristin L Campbell
- Cancer Prevention Program, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, M4-B402, Seattle, WA 98109-1024, USA
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Dei M, Seravalli V, Bruni V, Balzi D, Pasqua A. Predictors of recovery of ovarian function after weight gain in subjects with amenorrhea related to restrictive eating disorders. Gynecol Endocrinol 2008; 24:459-64. [PMID: 18850384 DOI: 10.1080/09513590802246141] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
OBJECTIVE The aim of the present study was to investigate the anthropometric and endocrine characteristics of subjects with amenorrhea related to eating disorders after weight recovery, in order to identify factors connected with the resumption of menses. METHODS Clinical data, body composition parameters and serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), thyroid-stimulating hormone (TSH), free triiodothyronine, free thyroxine, cortisol, leptin and insulin were assessed in two groups of young women classified according to menstrual status after weight rehabilitation: 43 subjects who displayed persistent amenorrhea and 34 who resumed menses. Univariate and multivariate logistic regression analyses were used to examine the relationships between the different parameters and menstrual recovery. RESULTS The patients who resumed menses had low initial weight and BMI, and a greater difference between current and initial BMI (DeltaBMI), than those with amenorrhea. No differences were observed in lean mass, body fat or bone density between the two groups. Moreover, the reduction in FSH and the increase in LH, insulin and leptin emerged as significant predictors of menstrual recovery. Increased DeltaBMI and insulin continued to be positive predictors in the multivariate analysis. CONCLUSION Following weight rehabilitation, the individual's metabolic set point before weight loss and the current insulin levels appear significant in predicting the reactivation of reproductive function.
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Affiliation(s)
- Metella Dei
- Pediatric and Adolescent Gynecology Unit, University of Florence, Florence, Italy.
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Chakrabarti P, Anno T, Manning BD, Luo Z, Kandror KV. The mammalian target of rapamycin complex 1 regulates leptin biosynthesis in adipocytes at the level of translation: the role of the 5'-untranslated region in the expression of leptin messenger ribonucleic acid. Mol Endocrinol 2008; 22:2260-7. [PMID: 18653778 DOI: 10.1210/me.2008-0148] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Leptin production by adipose cells in vivo is increased after feeding and decreased by food deprivation. However, molecular mechanisms that control leptin expression in response to food intake remain unknown. Here, we test the hypothesis that leptin expression in adipose cells is regulated by nutrient- and insulin-sensitive mammalian target of rapamycin complex 1 (mTORC1)-mediated pathway. The activity of mTORC1 in 3T3-L1 adipocytes was up-regulated by stable expression of either constitutively active Rheb or dominant-negative AMP-activated protein kinase. In both cases, expression of endogenous leptin was significantly elevated at the level of translation. To investigate the role of leptin 5'-untranslated region (UTR) in the regulation of protein expression, we created bicistronic reporter constructs with and without the 5'-UTR. We found that the presence of leptin 5'-UTR renders mRNA resistant to regulation by mTORC1. It appears, therefore, that mTORC1 controls translation of leptin mRNA via a novel mechanism that does not require the presence of either the 5'-terminal oligopyrimidine tract or the 5'-UTR.
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Zeigerer A, Rodeheffer MS, McGraw TE, Friedman JM. Insulin regulates leptin secretion from 3T3-L1 adipocytes by a PI 3 kinase independent mechanism. Exp Cell Res 2008; 314:2249-56. [PMID: 18501893 PMCID: PMC2997521 DOI: 10.1016/j.yexcr.2008.04.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 04/07/2008] [Accepted: 04/08/2008] [Indexed: 11/29/2022]
Abstract
To better define the molecular mechanisms underlying leptin release from adipocytes, we developed a novel protocol that maximizes leptin production from 3T3-L1 adipocytes. The addition of a PPARgamma agonist to the Isobutylmethylxanthine/Dexamethasone/Insulin differentiation cocktail increased leptin mRNA levels by 5-fold, maintained insulin sensitivity, and yielded mature phenotype in cultured adipocytes. Under these conditions, acute insulin stimulation for 2 h induced a two-fold increase in leptin secretion, which was independent of new protein synthesis, and was not due to alterations in glucose metabolism. Stimulation with insulin for 15 min induced the same level of leptin release and was blocked by Brefeldin A. Inhibiting PI 3-kinase with wortmannin had no effect on insulin stimulation of leptin secretion. These studies show that insulin can stimulate leptin release via a PI3K independent mechanism and provide a cellular system for studying the effect of insulin and potentially other mediators on leptin secretion.
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Affiliation(s)
- Anja Zeigerer
- Department of Molecular Genetics, The Rockefeller University, New York, NY 10021, USA
| | - Matthew S. Rodeheffer
- Department of Molecular Genetics, The Rockefeller University, New York, NY 10021, USA
| | - Timothy E. McGraw
- Department of Biochemistry, Weill Medical College of Cornell University, New York, NY 10021, USA
| | - Jeffrey M. Friedman
- Department of Molecular Genetics, The Rockefeller University, New York, NY 10021, USA
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She P, Van Horn C, Reid T, Hutson SM, Cooney RN, Lynch CJ. Obesity-related elevations in plasma leucine are associated with alterations in enzymes involved in branched-chain amino acid metabolism. Am J Physiol Endocrinol Metab 2007; 293:E1552-63. [PMID: 17925455 PMCID: PMC2767201 DOI: 10.1152/ajpendo.00134.2007] [Citation(s) in RCA: 371] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Elevations in branched-chain amino acids (BCAAs) in human obesity were first reported in the 1960s. Such reports are of interest because of the emerging role of BCAAs as potential regulators of satiety, leptin, glucose, cell signaling, adiposity, and body weight (mTOR and PKC). To explore loss of catabolic capacity as a potential contributor to the obesity-related rises in BCAAs, we assessed the first two enzymatic steps, catalyzed by mitochondrial branched chain amino acid aminotransferase (BCATm) or the branched chain alpha-keto acid dehydrogenase (BCKD E1alpha subunit) complex, in two rodent models of obesity (ob/ob mice and Zucker rats) and after surgical weight loss intervention in humans. Obese rodents exhibited hyperaminoacidemia including BCAAs. Whereas no obesity-related changes were observed in rodent skeletal muscle BCATm, pS293, or total BCKD E1alpha or BCKD kinase, in liver BCKD E1alpha was either unaltered or diminished by obesity, and pS293 (associated with the inactive state of BCKD) increased, along with BCKD kinase. In epididymal fat, obesity-related declines were observed in BCATm and BCKD E1alpha. Plasma BCAAs were diminished by an overnight fast coinciding with dissipation of the changes in adipose tissue but not in liver. BCAAs also were reduced by surgical weight loss intervention (Roux-en-Y gastric bypass) in human subjects studied longitudinally. These changes coincided with increased BCATm and BCKD E1alpha in omental and subcutaneous fat. Our results are consistent with the idea that tissue-specific alterations in BCAA metabolism, in liver and adipose tissue but not in muscle, may contribute to the rise in plasma BCAAs in obesity.
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Affiliation(s)
- Pengxiang She
- Department of Cellular and Molecular Physiology, College of Medicine, the Pennsylvania State University, Hershey, PA 17033
| | - Cynthia Van Horn
- Department of Biochemistry and Molecular Biology, Nutrition Research Center, Wake Forest University Health Sciences, Medical Center Blvd, Winston-Salem, NC 27157
| | - Tanya Reid
- Department of Biochemistry and Molecular Biology, Nutrition Research Center, Wake Forest University Health Sciences, Medical Center Blvd, Winston-Salem, NC 27157
| | - Susan M. Hutson
- Department of Biochemistry and Molecular Biology, Nutrition Research Center, Wake Forest University Health Sciences, Medical Center Blvd, Winston-Salem, NC 27157
| | - Robert N. Cooney
- Department of Cellular and Molecular Physiology, College of Medicine, the Pennsylvania State University, Hershey, PA 17033
- Department of Surgery, College of Medicine, the Pennsylvania State University, Hershey, PA 17033
| | - Christopher J. Lynch
- Department of Cellular and Molecular Physiology, College of Medicine, the Pennsylvania State University, Hershey, PA 17033
- Corresponding author: Christopher J. Lynch, Ph.D., Dept of Cellular and Molecular Physiology, MC-H166, Penn State University College of Medicine, 500 University Dr, Hershey, PA 17033. Ph: 717-531-5170, FAX: 717-531-7667,
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Christianson JL, Nicoloro S, Straubhaar J, Czech MP. Stearoyl-CoA desaturase 2 is required for peroxisome proliferator-activated receptor gamma expression and adipogenesis in cultured 3T3-L1 cells. J Biol Chem 2007; 283:2906-16. [PMID: 18032385 DOI: 10.1074/jbc.m705656200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Based on recent evidence that fatty acid synthase and endogenously produced fatty acid derivatives are required for adipogenesis in 3T3-L1 adipocytes, we conducted a small interfering RNA-based screen to identify other fatty acid-metabolizing enzymes that may mediate this effect. Of 24 enzymes screened, stearoyl-CoA desaturase 2 (SCD2) was found to be uniquely and absolutely required for adipogenesis. Remarkably, SCD2 also controls the maintenance of adipocyte-specific gene expression in fully differentiated 3T3-L1 adipocytes, including the expression of SCD1. Despite the high sequence similarity between SCD2 and SCD1, silencing of SCD1 did not down-regulate 3T3-L1 cell differentiation or gene expression. SCD2 mRNA expression was also uniquely elevated 44-fold in adipose tissue upon feeding mice a high fat diet, whereas SCD1 showed little response. The inhibition of adipogenesis caused by SCD2 depletion was associated with a decrease in peroxisome proliferator-activated receptor gamma (PPARgamma) mRNA and protein, whereas in mature adipocytes loss of SCD2 diminished PPARgamma protein levels, with little change in mRNA levels. In the latter case, SCD2 depletion did not change the degradation rate of PPARgamma protein but decreased the metabolic labeling of PPARgamma protein using [(35)S]methionine/cysteine, indicating protein translation was decreased. This requirement of SCD2 for optimal protein synthesis in fully differentiated adipocytes was verified by polysome profile analysis, where a shift in the mRNA to monosomes was apparent in response to SCD2 silencing. These results reveal that SCD2 is required for the induction and maintenance of PPARgamma protein levels and adipogenesis in 3T3-L1 cells.
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Affiliation(s)
- Jennifer L Christianson
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA
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