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Hemat Jouy S, Mohan S, Scichilone G, Mostafa A, Mahmoud AM. Adipokines in the Crosstalk between Adipose Tissues and Other Organs: Implications in Cardiometabolic Diseases. Biomedicines 2024; 12:2129. [PMID: 39335642 PMCID: PMC11428859 DOI: 10.3390/biomedicines12092129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2024] [Revised: 09/14/2024] [Accepted: 09/16/2024] [Indexed: 09/30/2024] Open
Abstract
Adipose tissue was previously regarded as a dormant organ for lipid storage until the identification of adiponectin and leptin in the early 1990s. This revelation unveiled the dynamic endocrine function of adipose tissue, which has expanded further. Adipose tissue has emerged in recent decades as a multifunctional organ that plays a significant role in energy metabolism and homeostasis. Currently, it is evident that adipose tissue primarily performs its function by secreting a diverse array of signaling molecules known as adipokines. Apart from their pivotal function in energy expenditure and metabolism regulation, these adipokines exert significant influence over a multitude of biological processes, including but not limited to inflammation, thermoregulation, immune response, vascular function, and insulin sensitivity. Adipokines are pivotal in regulating numerous biological processes within adipose tissue and facilitating communication between adipose tissue and various organs, including the brain, gut, pancreas, endothelial cells, liver, muscle, and more. Dysregulated adipokines have been implicated in several metabolic diseases, like obesity and diabetes, as well as cardiovascular diseases. In this article, we attempted to describe the significance of adipokines in developing metabolic and cardiovascular diseases and highlight their role in the crosstalk between adipose tissues and other tissues and organs.
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Affiliation(s)
- Shaghayegh Hemat Jouy
- Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, Central Tehran Branch, Islamic Azad University, Tehran 14778-93855, Iran;
| | - Sukrutha Mohan
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, College of Medicine, University of Illinois Chicago, Chicago, IL 60612, USA; (S.M.); (G.S.)
| | - Giorgia Scichilone
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, College of Medicine, University of Illinois Chicago, Chicago, IL 60612, USA; (S.M.); (G.S.)
| | - Amro Mostafa
- Department of Pharmacology, College of Medicine, University of Illinois Chicago, Chicago, IL 60612, USA;
| | - Abeer M. Mahmoud
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, College of Medicine, University of Illinois Chicago, Chicago, IL 60612, USA; (S.M.); (G.S.)
- Department of Kinesiology and Nutrition, College of Applied Health Sciences, University of Illinois Chicago, Chicago, IL 60612, USA
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Bełtowski J. Salt Intake, Aldosterone Secretion, and Obesity: Role in the Pathogenesis of Resistant Hypertension. Am J Hypertens 2021; 34:588-590. [PMID: 33438728 DOI: 10.1093/ajh/hpab015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 01/12/2021] [Indexed: 12/13/2022] Open
Affiliation(s)
- Jerzy Bełtowski
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
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Dai H, Wang F, Kang Y, Sun J, Zhou H, Gao Q, Li Z, Qian P, Zhu G, Zhou Y. Adrenomedullin Attenuates Inflammation in White Adipose Tissue of Obese Rats Through Receptor-Mediated PKA Pathway. Obesity (Silver Spring) 2021; 29:86-97. [PMID: 32985779 PMCID: PMC7821304 DOI: 10.1002/oby.23012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 08/04/2020] [Accepted: 08/05/2020] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Adrenomedullin (ADM) possesses therapeutic potential for inflammatory diseases. Consequently, the effects of ADM on inflammation in visceral white adipose tissue (vWAT) of obese rats or in adipocytes were explored in this study. METHODS Male rats were fed a high-fat diet for 12 weeks to induce obesity, and obese rats were implanted with osmotic minipumps providing constant infusion of ADM (300 ng/kg per hour) and continued to be fed a high-fat diet for 4 weeks. RESULTS When compared with the control group, endogenous protein expression of ADM and ADM receptors in vWAT and in lipopolysaccharide (LPS)-treated adipocytes was markedly increased. ADM significantly decreased the protein expression of the inflammatory mediators TNFα, IL-1β, cyclooxygenase-2, and inducible nitric oxide synthase in vWAT of obese rats and in adipocytes stimulated by LPS. It also inhibited the activation of the inflammatory signaling pathways MAPK and NF-κB induced by LPS in adipocytes. These effects of ADM in adipocytes were inhibited by the administration of ADM receptor antagonist and cAMP-dependent protein kinase (PKA) activation inhibitor. CONCLUSIONS ADM can inhibit inflammation in WAT in obesity, which may be mediated by the activation of ADM receptors and PKA.
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Affiliation(s)
- Hang‐Bing Dai
- Department of PhysiologyNanjing Medical UniversityNanjingChina
| | - Fang‐Zheng Wang
- Department of PhysiologyNanjing Medical UniversityNanjingChina
| | - Ying Kang
- Department of PhysiologyNanjing Medical UniversityNanjingChina
| | - Jing Sun
- Department of PhysiologyNanjing Medical UniversityNanjingChina
| | - Hong Zhou
- Department of PhysiologyNanjing Medical UniversityNanjingChina
| | - Qing Gao
- Department of PhysiologyNanjing Medical UniversityNanjingChina
| | - Zhen‐Zhen Li
- Department of CardiologyBenQ Medical CenterThe Affiliated Hospital of Nanjing Medical UniversityNanjingJiangsuChina
| | - Pei Qian
- Department of PhysiologyNanjing Medical UniversityNanjingChina
| | - Guo‐Qing Zhu
- Department of PhysiologyNanjing Medical UniversityNanjingChina
| | - Ye‐Bo Zhou
- Department of PhysiologyNanjing Medical UniversityNanjingChina
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Dong Y, van der Walt N, Pennington KA, Yallampalli C. Impact of adrenomedullin blockage on lipid metabolism in female mice exposed to high-fat diet. Endocrine 2019; 65:278-285. [PMID: 31025262 PMCID: PMC6901288 DOI: 10.1007/s12020-019-01927-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 04/08/2019] [Indexed: 12/11/2022]
Abstract
PURPOSE Adrenomedullin (ADM) levels are elevated in gestational and type 2 diabetic patients. ADM also stimulates lipolysis in vitro. Disturbed lipid metabolism has been implicated in the pathogenesis of diabetes. Here, we explore whether blockade of ADM is beneficial for metabolic homeostasis in a diabetic mouse model. METHODS C57BL/6J female mice were placed on either a control or a high fat high sucrose (HFHS) diet for 8 weeks. At week 4, osmotic mini-pumps were implanted for constant infusion of either saline or ADM antagonist, ADM22-52. Glucose tolerance tests were performed prior to infusion and 4 weeks after infusion began. Animals were then sacrificed and visceral adipose tissue collected for further analysis. RESULTS Mice fed HFHS displayed glucose intolerance, increased mRNA expressions in VAT for Adm and its receptor components, Crlr. HFHS fed mice also had increased basal and isoprenaline-induced glycerol release by VAT explants. ADM22-52 did not significantly affect glucose intolerance. ADM22-52 did suppress basal and isoprenaline-induced glycerol release by VAT explants. This alteration was associated with enhanced mRNA expression of insulin signaling factors Insr and Glut4, and adipogenic factor Pck1. CONCLUSIONS HFHS diet induces glucose intolerance and enhances ADM and its receptor expressions in VAT in female mice. ADM22-52 treatment did not affect glucose intolerance in HFHS mice, but reduced both basal and isoprenaline-induced lipolysis, which is associated with enhanced expression of genes involved in adipogenesis. These results warrant further research on the effects of ADM blockade in improving lipid homeostasis in diabetic patients.
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Affiliation(s)
- Yuanlin Dong
- Department of Obstetrics and Gynecology, Baylor College of Medicine/Texas Children's Hospital, Houston, TX, 77030, USA
| | - Nicola van der Walt
- Department of Obstetrics and Gynecology, Baylor College of Medicine/Texas Children's Hospital, Houston, TX, 77030, USA
| | - Kathleen A Pennington
- Department of Obstetrics and Gynecology, Baylor College of Medicine/Texas Children's Hospital, Houston, TX, 77030, USA
| | - Chandra Yallampalli
- Department of Obstetrics and Gynecology, Baylor College of Medicine/Texas Children's Hospital, Houston, TX, 77030, USA.
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Dong Y, Betancourt A, Belfort M, Yallampalli C. Targeting Adrenomedullin to Improve Lipid Homeostasis in Diabetic Pregnancies. J Clin Endocrinol Metab 2017; 102:3425-3436. [PMID: 28666334 PMCID: PMC5587055 DOI: 10.1210/jc.2017-00920] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 06/23/2017] [Indexed: 12/29/2022]
Abstract
Context Gestational diabetes mellitus (GDM) is associated with disturbances in maternal lipid metabolism. Hypertriacylglycerolemia in GDM is associated with an increased risk of large for gestational age neonates, but the pathogenesis of disrupted lipid homeostasis remains unclear. Objectives To determine the role of adrenomedullin (AM), a multifunctional peptide, in lipid metabolism in GDM. Design Omental adipose biopsies were collected in term pregnancy from women with normal glucose tolerance (NGT, n = 10) and GDM (n = 10). Results AM and its receptor components, calcitonin receptor-like receptor, receptor activity-modifying protein 2, and receptor activity-modifying protein 3, were higher in adipose tissues from GDM compared with NGT pregnancies, and these expressions in normal adipose tissues were enhanced by glucose and tumor necrosis factor-αin vitro. AM dose- and time-dependently stimulated lipolysis in human adipocytes, and this effect was reversed by AM antagonist AM22-52. Furthermore, AM inhibited phosphorylation of insulin receptor-β and insulin receptor substrate-1 and enhanced the protein expression of leptin and resistin in adipose tissue from NGT women. The increased messenger RNA expression of leptin and resistin in adipose tissue from GDM was reduced by AM22-52 treatment. Conclusions GDM pregnancies are associated with increased AM and its receptor expression in adipose tissues. AM stimulates lipolysis and leptin and resistin expression, and these effects can be reversed by AM antagonist. To our knowledge, manipulation of AM and its receptors in adipocytes might represent an approach in reducing the risk of GDM and fetal overgrowth.
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Affiliation(s)
- Yuanlin Dong
- Department of Obstetrics and Gynecology, Baylor College of Medicine/Texas Children’s Hospital, Houston, Texas 77030
| | - Ancizar Betancourt
- Department of Obstetrics and Gynecology, Baylor College of Medicine/Texas Children’s Hospital, Houston, Texas 77030
| | - Michael Belfort
- Department of Obstetrics and Gynecology, Baylor College of Medicine/Texas Children’s Hospital, Houston, Texas 77030
| | - Chandrasekhar Yallampalli
- Department of Obstetrics and Gynecology, Baylor College of Medicine/Texas Children’s Hospital, Houston, Texas 77030
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Liu T, Kamiyoshi A, Sakurai T, Ichikawa-Shindo Y, Kawate H, Yang L, Tanaka M, Xian X, Imai A, Zhai L, Hirabayashi K, Dai K, Tanimura K, Liu T, Cui N, Igarashi K, Yamauchi A, Shindo T. Endogenous Calcitonin Gene-Related Peptide Regulates Lipid Metabolism and Energy Homeostasis in Male Mice. Endocrinology 2017; 158:1194-1206. [PMID: 28324021 DOI: 10.1210/en.2016-1510] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 01/12/2017] [Indexed: 11/19/2022]
Abstract
Calcitonin gene-related peptide (CGRP) is a bioactive peptide produced by alternative splicing of the primary transcript of the calcitonin/CGRP gene. CGRP is largely distributed in the cardiovascular and nervous systems, where it acts as a regulatory factor. CGRP is also expressed in organs and tissues involved in metabolic regulation, including white adipose tissue (WAT), where its function is largely unknown. In this study, we examined the effects of endogenous CGRP on metabolic function. When we administered a high-fat diet to CGRP-specific knockout (CGRP-/-) and wild-type (WT) mice for 10 weeks, we observed that food intake did not differ between the two groups, but body weight and visceral fat weight were significantly lower in CGRP-/- mice. Fatty liver changes were less severe in CGRP-/- mice, which also showed lower serum insulin and leptin levels. Glucose tolerance and insulin sensitivity were better in CGRP-/- than WT mice, and expired gas analysis revealed greater oxygen consumption by CGRP-/- mice. Adipocyte hypertrophy was suppressed in CGRP-/- mice, while expression of β-3-adrenergic receptor, hormone-sensitive lipase and adiponectin was enhanced. Isoproterenol-induced glycerol release from WAT was higher in CGRP-/- than WT mice, and CGRP-/- mice showed elevated sympathetic nervous activity. β-receptor-blockade canceled the beneficial effects of CGRP deletion on obesity. These results suggest that, in addition to its actions in the cardiovascular system, endogenous CGRP is a key regulator of metabolism and energy homeostasis in vivo.
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Affiliation(s)
- Tian Liu
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | - Akiko Kamiyoshi
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | - Takayuki Sakurai
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | - Yuka Ichikawa-Shindo
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | - Hisaka Kawate
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | - Lei Yang
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | - Megumu Tanaka
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | - Xian Xian
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | - Akira Imai
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | - Liuyu Zhai
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | - Kazutaka Hirabayashi
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | - Kun Dai
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | - Keiya Tanimura
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | - Teng Liu
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | - Nanqi Cui
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
| | | | | | - Takayuki Shindo
- Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Nagano 390-8621, Japan
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Sagar G, Sah RP, Javeed N, Dutta SK, Smyrk TC, Lau JS, Giorgadze N, Tchkonia T, Kirkland J, Chari ST, Mukhopadhyay D. Pathogenesis of pancreatic cancer exosome-induced lipolysis in adipose tissue. Gut 2016; 65:1165-74. [PMID: 26061593 PMCID: PMC5323066 DOI: 10.1136/gutjnl-2014-308350] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 04/03/2015] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND OBJECTIVES New-onset diabetes and concomitant weight loss occurring several months before the clinical presentation of pancreatic cancer (PC) appear to be paraneoplastic phenomena caused by tumour-secreted products. Our recent findings have shown exosomal adrenomedullin (AM) is important in development of diabetes in PC. Adipose tissue lipolysis might explain early onset weight loss in PC. We hypothesise that lipolysis-inducing cargo is carried in exosomes shed by PC and is responsible for the paraneoplastic effects. Therefore, in this study we investigate if exosomes secreted by PC induce lipolysis in adipocytes and explore the role of AM in PC-exosomes as the mediator of this lipolysis. DESIGN Exosomes from patient-derived cell lines and from plasma of patients with PC and non-PC controls were isolated and characterised. Differentiated murine (3T3-L1) and human adipocytes were exposed to these exosomes to study lipolysis. Glycerol assay and western blotting were used to study lipolysis. Duolink Assay was used to study AM and adrenomedullin receptor (ADMR) interaction in adipocytes treated with exosomes. RESULTS In murine and human adipocytes, we found that both AM and PC-exosomes promoted lipolysis, which was abrogated by ADMR blockade. AM interacted with its receptor on the adipocytes, activated p38 and extracellular signal-regulated (ERK1/2) mitogen-activated protein kinases and promoted lipolysis by phosphorylating hormone-sensitive lipase. PKH67-labelled PC-exosomes were readily internalised into adipocytes and involved both caveolin and macropinocytosis as possible mechanisms for endocytosis. CONCLUSIONS PC-secreted exosomes induce lipolysis in subcutaneous adipose tissue; exosomal AM is a candidate mediator of this effect.
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Affiliation(s)
- Gunisha Sagar
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester
| | - Raghuwansh P. Sah
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester
| | - Naureen Javeed
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester
| | - Shamit K Dutta
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester
| | - Thomas C Smyrk
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester
| | - Julie S Lau
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester
| | - Nino Giorgadze
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester MN, USA
| | - Tamar Tchkonia
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester MN, USA
| | - James Kirkland
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester MN, USA
| | - Suresh T Chari
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester MN, USA
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Wang D, Zeng J, Li Q, Huang J, Couture R, Hong Y. Contribution of adrenomedullin to the switch of G protein-coupled μ-opioid receptors from Gi to Gs in the spinal dorsal horn following chronic morphine exposure in rats. Br J Pharmacol 2016; 173:1196-207. [PMID: 26750148 DOI: 10.1111/bph.13419] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 12/30/2015] [Accepted: 01/07/2016] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND AND PURPOSE Chronic exposure to morphine increases spinal adrenomedullin (AM) bioactivity resulting in the development and maintenance of morphine tolerance. This study investigated the possible involvement of AM in morphine-evoked alteration in μ-opioid receptor-coupled G proteins. EXPERIMENTAL APPROACH Agents were administered intrathecally (i.t.) in rats. Nociceptive behaviours and cumulative dose-response of morphine analgesia were assessed. Neurochemicals in the spinal dorsal horn were assayed by immunoprecipitation, Western blot analysis and ELISA. KEY RESULTS Intrathecal injection of AM (8 μg) for 9 days decreased and increased the levels of μ receptor-coupled Gi and Gs proteins respectively. Morphine stimulation (5 μg) after chronic treatment with AM also induced an increase in cAMP production in the spinal dorsal horn. Co-administration of the selective AM receptor antagonist AM22-52 inhibited chronic morphine-evoked switch of G protein-coupled μ receptor from Gi to Gs. Chronic exposure to AM increased the phosphorylation of cAMP-responsive element-binding protein (CREB) and ERK. Co-administration of the PKA inhibitor H-89 (5 μg) or MEK1 inhibitor PD98059 (1 μg) reversed the AM-induced thermal/mechanical hypersensitivity, decline in morphine analgesic potency, switch of G protein-coupled μ receptor and increase in cAMP. CONCLUSIONS AND IMPLICATIONS The present study supports the hypothesis that an increase in AM activity in the spinal dorsal horn contributes to the switch of the μ receptor-coupled G protein from Gi to Gs protein via the activation of cAMP/PKA/CREB and ERK signalling pathways in chronic morphine use.
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Affiliation(s)
- Dongmei Wang
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University, Fuzhou, Fujian, China
| | - Juan Zeng
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University, Fuzhou, Fujian, China
| | - Qi Li
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University, Fuzhou, Fujian, China
| | - Jianzhong Huang
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University, Fuzhou, Fujian, China
| | - Réjean Couture
- Department of Molecular and Integrative Physiology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Yanguo Hong
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University, Fuzhou, Fujian, China
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Walker CS, Hay DL, Fitzpatrick SM, Cooper GJS, Loomes KM. α-Calcitonin gene related peptide (α-CGRP) mediated lipid mobilization in 3T3-L1 adipocytes. Peptides 2014; 58:14-9. [PMID: 24887115 DOI: 10.1016/j.peptides.2014.05.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/21/2014] [Accepted: 05/21/2014] [Indexed: 11/29/2022]
Abstract
The neuropeptide, α-calcitonin gene-related peptide (α-CGRP), is expressed from sensory nerves that innervate fat. However, how α-CGRP may act in adipose tissue is unclear. Using 3T3-L1 adipocytes we observed that rat α-CGRP (rα-CGRP) evoked either a biphasic or monophasic reduction in intracellular free fatty acid (FFA) content. cAMP production was always monophasic and occurred when FFA responses were absent. Taken together with the observed potencies, these findings suggest that adipose tissue is a physiological target for α-CGRP. However, uncoupling of the FFA and CGRP-signaling responses with increasing passage number limits 3T3-L1 adipocytes as a suitable cellular model.
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Affiliation(s)
- Christopher S Walker
- School of Biological Sciences, University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.
| | - Debbie L Hay
- School of Biological Sciences, University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | | | - Garth J S Cooper
- School of Biological Sciences, University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Kerry M Loomes
- School of Biological Sciences, University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.
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Abstract
In adipocytes the hydrolysis of TAG to produce fatty acids and glycerol under fasting conditions or times of elevated energy demands is tightly regulated by neuroendocrine signals, resulting in the activation of lipolytic enzymes. Among the classic regulators of lipolysis, adrenergic stimulation and the insulin-mediated control of lipid mobilisation are the best known. Initially, hormone-sensitive lipase (HSL) was thought to be the rate-limiting enzyme of the first lipolytic step, while we now know that adipocyte TAG lipase is the key enzyme for lipolysis initiation. Pivotal, previously unsuspected components have also been identified at the protective interface of the lipid droplet surface and in the signalling pathways that control lipolysis. Perilipin, comparative gene identification-58 (CGI-58) and other proteins of the lipid droplet surface are currently known to be key regulators of the lipolytic machinery, protecting or exposing the TAG core of the droplet to lipases. The neuroendocrine control of lipolysis is prototypically exerted by catecholaminergic stimulation and insulin-induced suppression, both of which affect cyclic AMP levels and hence the protein kinase A-mediated phosphorylation of HSL and perilipin. Interestingly, in recent decades adipose tissue has been shown to secrete a large number of adipokines, which exert direct effects on lipolysis, while adipocytes reportedly express a wide range of receptors for signals involved in lipid mobilisation. Recently recognised mediators of lipolysis include some adipokines, structural membrane proteins, atrial natriuretic peptides, AMP-activated protein kinase and mitogen-activated protein kinase. Lipolysis needs to be reanalysed from the broader perspective of its specific physiological or pathological context since basal or stimulated lipolytic rates occur under diverse conditions and by different mechanisms.
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Wong HK, Ong KL, Leung RYH, Cheung TT, Xu A, Lam TH, Lam KSL, Cheung BMY. Plasma level of adrenomedullin is influenced by a single nucleotide polymorphism in the adiponectin gene. PLoS One 2013; 8:e70335. [PMID: 23936408 PMCID: PMC3731362 DOI: 10.1371/journal.pone.0070335] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 06/22/2013] [Indexed: 12/17/2022] Open
Abstract
Objective Adrenomedullin (ADM) and adiponectin are both involved in inflammation and cardiovascular diseases. The plasma levels of these peptides are influenced by single nucleotide polymorphisms (SNPs) in the ADM and ADIPOQ genes respectively. There is some evidence that ADM may regulate adiponectin gene expression, but whether adiponectin can regulate ADM expression is unclear, and was therefore investigated. Methods Plasma ADM level was measured in 476 subjects in the Hong Kong Cardiovascular Risk Factor Prevalence Study-2 (CRISPS2). We genotyped them for 2 ADIPOQ SNPs that are known to be associated with plasma adiponectin level. Results The minor allele frequencies of ADIPOQ SNPs rs182052 and rs12495941 were 40.6% and 42.2% respectively. Plasma ADM level was significantly associated with rs182052 after adjusting for age and sex (β = 0.104, P = 0.023) but not with rs12495941 (β = 0.071, P = 0.120). In multivariate analysis, plasma ADM level increased with the number of minor alleles of rs182052 (P = 0.013). Compared to subjects with GG genotype, subjects with AA genotype had 17.7% higher plasma ADM level (95% CI: 3.6%–33.7%). Subgroup analysis revealed that the association was significant in diabetic patients (β = 0.344, P = 0.001) but not in non-diabetic subjects. Conclusion Plasma ADM level is related to SNP rs182052 in the ADIPOQ gene. Our findings provide new evidence of the interplay between these two important peptides in cardiovascular disease and diabetes. Knowing the genotype may help to refine the interpretation of these biomarkers.
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Affiliation(s)
- Hoi Kin Wong
- Department of Medicine, University of Hong Kong, Hong Kong
| | - Kwok Leung Ong
- Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia
| | | | | | - Aimin Xu
- Department of Medicine, University of Hong Kong, Hong Kong
| | - Tai Hing Lam
- Department of Community Medicine and School of Public Health, University of Hong Kong, Hong Kong
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Cherian S, Lopaschuk GD, Carvalho E. Cellular cross-talk between epicardial adipose tissue and myocardium in relation to the pathogenesis of cardiovascular disease. Am J Physiol Endocrinol Metab 2012; 303:E937-49. [PMID: 22895783 DOI: 10.1152/ajpendo.00061.2012] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Epicardial and perivascular fat depot size is considered an index of cardiac and visceral obesity. The functional and anatomic proximity of epicardial adipose tissue (EAT) to myocardium has drawn increasing attention in recent years among researchers attempting to elucidate its putative role as an endocrine organ. This includes the role of EAT as a lipid storing depot and as an inflammatory tissue secreting cytokines and chemokines under pathogenic conditions such as cardiovascular diseases. In this review, we discuss the current state of knowledge regarding the potential EAT mediators of inflammation and the paracrine cross-talk between EAT and the underlying myocardium. We also highlight the most recent findings on the causes and correlates of myocardial steatosis/cardiac lipotoxicity and its association with cardiac dysfunction.
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Affiliation(s)
- Sam Cherian
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
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Zhang X, Gu L, Chen X, Wang S, Deng X, Liu K, Lv Z, Yang R, He S, Peng Y, Huang D, Jiang W, Wu K. Intermedin ameliorates atherosclerosis in ApoE null mice by modifying lipid profiles. Peptides 2012; 37:189-93. [PMID: 22910189 DOI: 10.1016/j.peptides.2012.07.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 07/11/2012] [Accepted: 07/12/2012] [Indexed: 02/05/2023]
Abstract
Intermedin (IMD) is a recently discovered vasodilator peptide. We studied the role of IMD in the pathogenesis of atherosclerosis by investigating the ability of exogenous IMD to alter lipid profiles and ameliorate the development of atherogenic-diet induced atherosclerosis in ApoE-/- mice. Ten of eight-week-old male C57BL/6J mice were as control. Thirty of eight-week-old male ApoE-/- mice were fed with an atherogenic diet for 18 weeks. After feeding atherogenic diet for 12 weeks, the mice were equally and randomly divided into three groups. Normal saline was given in group A and C57BL/6J mice. Intermedin was given by mini osmotic pumps at the dosage of 100 ng/kg/h and 500 ng/kg/h in group B and group C respectively. After the treatment of IMD for 6 weeks, aortic ultrasonography of group C showed that IMD prevented the progression of atherosclerotic lesions and the increase of wall thickness in the aorta. Oil-red-O staining of the entire aorta and the atherosclerotic aortic root section showed 2 folds decrease atherogenic plaque (p<0.05). Serum lipid profiles were measured, compared with the group A, in group C TC and LDL-C levels were decreased by 86.32% and 89.68%, respectively (both p<0.05), meanwhile, HDL-C level was significantly increased by 74.82% (p<0.05). These data indicate that exogenous administration of IMD could prevent the progression of atherosclerotic plaque. The possible underlying mechanisms may relate to the improvement of lipid profiles.
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Affiliation(s)
- Xin Zhang
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu 610041, China
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Stenberg TA, Kildal AB, How OJ, Myrmel T. Adrenomedullin-epinephrine cotreatment enhances cardiac output and left ventricular function by energetically neutral mechanisms. Am J Physiol Heart Circ Physiol 2012; 302:H1584-90. [PMID: 22307666 DOI: 10.1152/ajpheart.00887.2011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adrenomedullin (AM) used therapeutically reduces mortality in the acute phase of experimental myocardial infarction. However, AM is potentially deleterious in acute heart failure as it is vasodilative and inotropically neutral. AM and epinephrine (EPI) are cosecreted from chromaffin cells, indicating a physiological interaction. We assessed the hemodynamic and energetic profile of AM-EPI cotreatment, exploring whether drug interaction improves cardiac function. Left ventricular (LV) mechanoenergetics were evaluated in 14 open-chest pigs using pressure-volume analysis and the pressure-volume area-myocardial O(2) consumption (PVA-MVo(2)) framework. AM (15 ng·kg(-1)·min(-1), n = 8) or saline (controls, n = 6) was infused for 120 min. Subsequently, a concurrent infusion of EPI (50 ng·kg(-1)·min(-1)) was added in both groups (AM-EPI vs. EPI). AM increased cardiac output (CO) and coronary blood flow by 20 ± 10% and 39 ± 14% (means ± SD, P < 0.05 vs. baseline), whereas controls were unaffected. AM-EPI increased CO and coronary blood flow by 55 ± 17% and 75 ± 16% (P < 0.05, AM-EPI interaction) compared with 13 ± 12% (P < 0.05 vs. baseline) and 18 ± 31% (P = not significant) with EPI. LV systolic capacitance decreased by -37 ± 22% and peak positive derivative of LV pressure (dP/dt(max)) increased by 32 ± 7% with AM-EPI (P < 0.05, AM-EPI interaction), whereas no significant effects were observed with EPI. Mean arterial pressure was maintained by AM-EPI and tended to decrease with EPI (+2 ± 13% vs. -11 ± 10%, P = not significant). PVA-MVo(2) relationships were unaffected by all treatments. In conclusion, AM-EPI cotreatment has an inodilator profile with CO and LV function augmented beyond individual drug effects and is not associated with relative increases in energetic cost. This can possibly take the inodilator treatment strategy beyond hemodynamic goals and exploit the cardioprotective effects of AM in acute heart failure.
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Affiliation(s)
- Thor Allan Stenberg
- Surgical Research Laboratory, Department of Clinical Medicine, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.
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Zhang J, Zhang BH, Yu YR, Tang CS, Qi YF. Adrenomedullin protects against fructose-induced insulin resistance and myocardial hypertrophy in rats. Peptides 2011; 32:1415-21. [PMID: 21664393 DOI: 10.1016/j.peptides.2011.05.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 05/25/2011] [Accepted: 05/25/2011] [Indexed: 01/13/2023]
Abstract
Adrenomedullin (ADM) has been recognized as a multipotent multifunctional peptide. To explore the pathophysiological roles of ADM in insulin resistance (IR), we studied the changes in ADM mRNA level in the myocardium and vessels and the effect of ADM supplementation on rats with IR induced by fructose feeding. Rats were fed 4% fructose in drinking water for 8 weeks, and ADM was administered subcutaneously in pure water through an Alzet Mini-osmotic Pump at 300 ng/kg/h for the last 4 weeks. Compared with controls, rats with IR showed increased levels of fasting blood sugar and serum insulin, by 95% and 67%, respectively (all P<0.01), and glycogen synthesis and glucose transport activity of the soleus decreased by 54% and 55% (all P<0.01). mRNA level and content of brain natriuretic peptide (BNP) in myocardial were all increased significantly. Fructose-fed rats showed increased immunoreactive-ADM content in plasma by 110% and in myocardia by 55% and increased mRNA level in myocardia and vessels (all P<0.01). ADM administration ameliorated the induced IR and myocardial hypertrophy. The glycogen synthesis and glucose transport activity of the soleus muscle increased by 41% (P<0.01) and 32% (P<0.05). ADM therapy attenuated myocardial and soleus lipid peroxidation injury and enhanced the antioxidant ability. Our results showed upregulation of endogenous ADM during fructose-induced IR and the protective effect of ADM on fructose-induced IR and concomitant cardiovascular hypertrophy probably by its antioxidant effect, which suggests that ADM could be an endogenous protective factor in IR.
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Affiliation(s)
- Jing Zhang
- School of P.E. and Sports Science, Beijing Normal University, Beijing 100875, China
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Yen DHT, Chen LC, Shen YC, Chiu YC, Ho IC, Lou YJ, Chen IC, Yen JC. Protein kinase A-dependent neuronal nitric oxide synthase activation mediates the enhancement of baroreflex response by adrenomedullin in the nucleus tractus solitarii of rats. J Biomed Sci 2011; 18:32. [PMID: 21595896 PMCID: PMC3115842 DOI: 10.1186/1423-0127-18-32] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 05/19/2011] [Indexed: 11/10/2022] Open
Abstract
Background Adrenomedullin (ADM) exerts its biological functions through the receptor-mediated enzymatic mechanisms that involve protein kinase A (PKA), or neuronal nitric oxide synthase (nNOS). We previously demonstrated that the receptor-mediated cAMP/PKA pathway involves in ADM-enhanced baroreceptor reflex (BRR) response. It remains unclear whether ADM may enhance BRR response via activation of nNOS-dependent mechanism in the nucleus tractus solitarii (NTS). Methods Intravenous injection of phenylephrine was administered to evoke the BRR before and at 10, 30, and 60 min after microinjection of the test agents into NTS of Sprague-Dawley rats. Western blotting analysis was used to measure the level and phosphorylation of proteins that involved in BRR-enhancing effects of ADM (0.2 pmol) in NTS. The colocalization of PKA and nNOS was examined by immunohistochemical staining and observed with a laser confocal microscope. Results We found that ADM-induced enhancement of BRR response was blunted by microinjection of NPLA or Rp-8-Br-cGMP, a selective inhibitor of nNOS or protein kinase G (PKG) respectively, into NTS. Western blot analysis further revealed that ADM induced an increase in the protein level of PKG-I which could be attenuated by co-microinjection with the ADM receptor antagonist ADM22-52 or NPLA. Moreover, we observed an increase in phosphorylation at Ser1416 of nNOS at 10, 30, and 60 min after intra-NTS administration of ADM. As such, nNOS/PKG signaling may also account for the enhancing effect of ADM on BRR response. Interestingly, biochemical evidence further showed that ADM-induced increase of nNOS phosphorylation was prevented by co-microinjection with Rp-8-Br-cAMP, a PKA inhibitor. The possibility of PKA-dependent nNOS activation was substantiated by immunohistochemical demonstration of co-localization of PKA and nNOS in putative NTS neurons. Conclusions The novel finding of this study is that the signal transduction cascade that underlies the enhancement of BRR response by ADM in NTS is composed sequentially of cAMP/PKA and nNOS/PKG pathways.
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Affiliation(s)
- David H T Yen
- Institute of Emergency and Critical Care Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
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Henein HY, Younan SM, Rashed LA, Fakhry A. Effect of adrenomedullin gene delivery on insulin resistance in type 2 diabetic rats. J Adv Res 2011. [DOI: 10.1016/j.jare.2010.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Shibasaki I, Nishikimi T, Mochizuki Y, Yamada Y, Yoshitatsu M, Inoue Y, Kuwata T, Ogawa H, Tsuchiya G, Ishimitsu T, Fukuda H. Greater expression of inflammatory cytokines, adrenomedullin, and natriuretic peptide receptor-C in epicardial adipose tissue in coronary artery disease. ACTA ACUST UNITED AC 2010; 165:210-7. [PMID: 20691218 DOI: 10.1016/j.regpep.2010.07.169] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Revised: 07/16/2010] [Accepted: 07/27/2010] [Indexed: 12/12/2022]
Abstract
BACKGROUND Growing evidence suggests that the epicardial adipose tissue may have local interactions with coronary arteries. In addition, vasoactive peptides such as adrenomedullin and natriuretic peptide has an interaction with adipose tissue. In this study, we investigated the relationship between adipokines, adipocytokines, and vasoactive peptides expressed in epicardial adipose tissue and subcutaneous adipose tissue in patients with and without coronary artery disease (CAD). METHODS We studied 20 patients with CAD and 14 patients without CAD. We obtained blood samples and epicardial and subcutaneous adipose tissue at open-heart surgery. We measured serum cytokine levels and used real-time polymerase chain reaction (PCR) to measure mRNA levels of various molecules in epicardial and subcutaneous tissue and investigated the relation between mRNA levels and clinical parameters. RESULTS The mRNA levels of IL-6, IL-1beta, MCP-1, and TNF-alpha were significantly higher in epicardial adipose tissue than in subcutaneous adipose tissue. Interestingly, the mRNA levels of IL-6, IL-1beta, MCP-1, natriuretic peptide receptor-C (NPR-C), adrenomedullin, and leptin in epicardial adipose tissue were higher in patients with CAD than those without CAD. In contrast, mRNA levels of adiponectin, PPAR-gamma, and NPR-A were similar in the two groups. In subcutaneous tissue, mRNA expressions of IL-6, IL-1beta, MCP-1, NPR-C, adrenomedullin, and leptin were modestly higher in patients with CAD than in those without CAD. There were no differences in plasma cytokine levels between the two groups. CONCLUSION The mRNA levels of inflammatory cytokines, adipokines, neurohumoral factors and their receptors appear to be increased in epicardial adipose tissue independent of plasma levels of these molecules. Further studies are necessary to elucidate the pathophysiological role of these molecules in CAD.
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Affiliation(s)
- Ikuko Shibasaki
- Department of Cardiothoracic Surgery and Cardiorenal Medicine, Dokkyo Medical University, Mibu, Tochigi, Japan
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Release of inflammatory mediators by human adipose tissue is enhanced in obesity and primarily by the nonfat cells: a review. Mediators Inflamm 2010; 2010:513948. [PMID: 20508843 PMCID: PMC2874930 DOI: 10.1155/2010/513948] [Citation(s) in RCA: 170] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 01/27/2010] [Accepted: 02/23/2010] [Indexed: 02/08/2023] Open
Abstract
This paper considers the role of putative adipokines that might be involved in the enhanced inflammatory response of human adipose tissue seen in obesity. Inflammatory adipokines [IL-6, IL-10, ACE, TGFbeta1, TNFalpha, IL-1beta, PAI-1, and IL-8] plus one anti-inflammatory [IL-10] adipokine were identified whose circulating levels as well as in vitro release by fat are enhanced in obesity and are primarily released by the nonfat cells of human adipose tissue. In contrast, the circulating levels of leptin and FABP-4 are also enhanced in obesity and they are primarily released by fat cells of human adipose tissue. The relative expression of adipokines and other proteins in human omental as compared to subcutaneous adipose tissue as well as their expression in the nonfat as compared to the fat cells of human omental adipose tissue is also reviewed. The conclusion is that the release of many inflammatory adipokines by adipose tissue is enhanced in obese humans.
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Current world literature. Curr Opin Endocrinol Diabetes Obes 2010; 17:177-85. [PMID: 20190584 DOI: 10.1097/med.0b013e3283382286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Talas ZS, Ozdemir I, Gok Y, Ates B, Yilmaz I. Role of selenium compounds on tyrosine hydroxylase activity, adrenomedullin and total RNA levels in hearts of rats. REGULATORY PEPTIDES 2010; 159:137-141. [PMID: 19706312 DOI: 10.1016/j.regpep.2009.08.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 07/31/2009] [Accepted: 08/12/2009] [Indexed: 12/18/2022]
Abstract
Synthetic organoselenium compounds can be tailored to achieve greater chemopreventive efficacy with minimal toxic side effects by structural modifications. Two organoselenium compounds (Se I and Se II) were synthesized and evaluated for their antihypertensive and therapeutic properties by adrenomedullin (ADM) levels and tyrosine hydroxylase (TH) activity assays in rat heart tissue. 7,12-Dimethylbenz[a]anthracene (DMBA) is known to generate DNA-reactive species during their metabolism, which may enhance oxidative stress in cells. TH is thought to be a rate-limiting enzyme in the biosynthesis of catecholamines. ADM, a potent endogenous vasodilating and natriuretic peptide, may play an important role in the pathophysiology of chronic heart failure. The effects of Se I and Se II were investigated on TH activity, ADM and total RNA levels in the hearts of albino Wistar rats. TH activity was found to be increased significantly by the effect of DMBA (P<0.05). This increase was restricted in the Se I and Se II treated groups. ADM level was found to be decreased insignificantly by the effect of DMBA (P>0.05). Total RNA level was found to be decreased significantly by the effect of DMBA (P<0.05). This study demonstrates that synthetic organoselenium compounds can regulate DMBA-induced stress related changes in rat heart.
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Affiliation(s)
- Zeliha Selamoglu Talas
- Department of Biology, Faculty of Arts and Science, Nigde University, Nigde, 51200 Turkey.
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Increased plasma levels of the mature and intermediate forms of adrenomedullin in obesity. ACTA ACUST UNITED AC 2009; 158:127-31. [PMID: 19706311 DOI: 10.1016/j.regpep.2009.08.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 06/20/2009] [Accepted: 08/16/2009] [Indexed: 11/21/2022]
Abstract
Adrenomedullin (AM) is a cardiovascular protective peptide produced in various organs and tissues including adipose tissue. In the present study, we measured the plasma AM levels of subjects with or without obesity by two assay methods to separately evaluate the biologically active AM-NH(2) and the intermediate form of AM-glycine (AM-Gly). We measured the total AM and AM-NH(2) levels of plasma in 52 obese and 172 non-obese residents of a Japanese community, who received regular health check-ups and had no overt cardiovascular disease. AM-Gly values were obtained by subtracting AM-NH(2) levels from those of total AM. Both the AM-NH(2) and AM-Gly levels of the subjects with obesity were higher than those without obesity, and significant relationships were noted between body mass index (BMI) and the plasma levels of the two molecular forms of AM in a simple regression analysis. Moreover, the significant factors identified by multivariate analyses were BMI and serum triglyceride for AM-NH(2) and diastolic blood pressure, insulin, high-density lipoprotein-cholesterol, and plasma renin activity for AM-Gly. These results suggest active roles for the two molecular forms of AM in metabolic disorders associated with obesity in subjects without overt cardiovascular disease.
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Stimulatory and Inhibitory regulation of lipolysis by the NPR-A/cGMP/PKG and NPR-C/G(i) pathways in rat cultured adipocytes. ACTA ACUST UNITED AC 2008; 153:56-63. [PMID: 19027799 DOI: 10.1016/j.regpep.2008.10.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 09/27/2008] [Accepted: 10/26/2008] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Recent studies have suggested the abundant expression of natriuretic peptide receptor in adipose tissue. This study was designed to investigate the levels of natriuretic receptor-A (NPR-A) and NPR-C gene expression during the process of preadipocyte differentiation and its role in adipogenesis and lipid metabolism. METHODS We measured mRNA levels of NPR-A and NPR-C during the process of rat preadipocyte differentiation in vitro. We also measured the effects of ANP and C-ANP, a ligand for NPR-C, on preadipocyte differentiation. In addition, we assessed the effects of ANP and C-ANP on lipolysis and the cellular mechanism. RESULTS The mRNA levels of NPR-A and NPR-C on day 3, 6, 10 are (-26%, +226%), (+6%, +568%), and (+207%, +3232%) respectively as compared with day 1. ANP (10(-)(7) M) and 8-bromo-cGMP (10(-)(4) M) significantly increased Oil Red positive area and cell number of matured-adipocytes. ANP and 8-bromo-cGMP also increased the mRNA levels of adipocyte-related genes such as PPARgamma, leptin, and adiponectin on day 3, whereas C-ANP did not change these parameters. ANP (10(-)(9)-10(-)(6) M) increased intracellular cGMP levels and promoted lipolysis in adipocytes and the effects were abolished by HS-142-1, and KT5823. Conversely C-ANP (10(-)(6) M) decreased intracellular cAMP levels and lipolysis and its effect was inhibited by PTX. CONCLUSION Results suggest that ANP may promote adipocyte differentiation and lipolysis via the NPR-A/cGMP/PKG pathway. Direct action of ANP via NPR-C in adipogenesis may be either absent or barely present, but ANP may play a counter regulatory role in lipolysis via NPR-C/Gi pathway.
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