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Marques FZ, Eikelis N, Bayles RG, Lambert EA, Straznicky NE, Hering D, Esler MD, Head GA, Barton DA, Schlaich MP, Lambert GW. A polymorphism in the norepinephrine transporter gene is associated with affective and cardiovascular disease through a microRNA mechanism. Mol Psychiatry 2017; 22:134-141. [PMID: 27046647 DOI: 10.1038/mp.2016.40] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 02/11/2016] [Accepted: 02/17/2016] [Indexed: 12/31/2022]
Abstract
Norepinephrine released from sympathetic nerves is removed from the neuroeffector junction via the action of the norepinephrine transporter (NET). NET impairment is evident in several clinically important conditions including major depressive disorder (MDD), panic disorder (PD), essential hypertension and the postural orthostatic tachycardia syndrome (POTS). We aimed to determine whether a single nucleotide polymorphism (SNP) in the 3' untranslated region (UTR) of the NET gene is associated with NET impairment and to elucidate the mechanisms involved. The analyses were carried out in two cohorts of European ancestry, which included healthy controls and MDD, PD, hypertensive and POTS patients. Compared with controls, cases had significantly higher prevalence of the T allele of rs7194256 (C/T), arterial norepinephrine, depression and anxiety scores, larger left ventricular mass index, higher systolic and diastolic blood pressures, and heart rate. Bioinformatic analysis identified that the microRNA miR-19a-3p could bind preferentially to the sequence created by the presence of the T allele. This was supported by results of luciferase assays. Compared with controls, cases had significantly lower circulating miR-19a-3p, which was associated with pathways related to blood pressure and regulation of neurotransmission. In vitro norepinephrine downregulated miR-19a-3p. In conclusion, the T allele of the rs7194256 SNP in the 3'UTR of the NET gene is more prevalent in diseases where NET impairment is evident. This might be explained by the creation of a binding site for the microRNA miR-19a-3p. A defect in NET function may potentiate the sympathetic neurochemical signal, predisposing individuals with affective diseases to increased risk of cardiovascular disease development.
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Affiliation(s)
- F Z Marques
- The Heart Failure Research Group, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia.,The Central Clinical School, Faculty of Medicine, Monash University, Melbourne, VIC, Australia
| | - N Eikelis
- The Human Neurotransmitters Laboratories, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - R G Bayles
- The Human Neurotransmitters Laboratories, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - E A Lambert
- The Human Neurotransmitters Laboratories, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia.,The Department of Physiology, Monash University, Melbourne, VIC, Australia
| | - N E Straznicky
- The Human Neurotransmitters Laboratories, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - D Hering
- Neurovascular Hypertension & Kidney Disease Laboratories, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia.,Dobney Hypertension Centre, School of Medicine and Pharmacology, University of Western Australia, Perth, WA, Australia
| | - M D Esler
- The Central Clinical School, Faculty of Medicine, Monash University, Melbourne, VIC, Australia.,The Human Neurotransmitters Laboratories, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - G A Head
- Neuropharmacology Laboratories, Baker IDI Heart and Diabetes Research Institute, Melbourne, VIC, Australia.,The Department of Pharmacology, Monash University, Melbourne, VIC, Australia
| | - D A Barton
- The Central Clinical School, Faculty of Medicine, Monash University, Melbourne, VIC, Australia.,The Human Neurotransmitters Laboratories, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - M P Schlaich
- The Central Clinical School, Faculty of Medicine, Monash University, Melbourne, VIC, Australia.,Neurovascular Hypertension & Kidney Disease Laboratories, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia.,Dobney Hypertension Centre, School of Medicine and Pharmacology, University of Western Australia, Perth, WA, Australia
| | - G W Lambert
- The Central Clinical School, Faculty of Medicine, Monash University, Melbourne, VIC, Australia.,The Human Neurotransmitters Laboratories, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia
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Straznicky NE, Guo L, Corcoran SJ, Esler MD, Phillips SE, Sari CI, Grima MT, Karapanagiotidis S, Wong CY, Eikelis N, Mariani JA, Kobayashi D, Dixon JB, Lambert GW, Lambert EA. Norepinephrine transporter expression is inversely associated with glycaemic indices: a pilot study in metabolically diverse persons with overweight and obesity. Obes Sci Pract 2016; 2:13-23. [PMID: 27812376 PMCID: PMC5066670 DOI: 10.1002/osp4.20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 10/04/2015] [Accepted: 10/09/2015] [Indexed: 01/20/2023] Open
Abstract
Objective The objective of this study was to examine the cross‐sectional relationship between the expression of norepinephrine transporter (NET), the protein responsible for neuronal uptake‐1, and indices of glycaemia and hyperinsulinaemia, in overweight and obese individuals. Methods Thirteen non‐medicated, non‐smoking subjects, aged 58 ± 1 years (mean ± standard error of the mean), body mass index (BMI) 31.4 ± 1.0 kg m−2, with wide‐ranging plasma glucose and haemoglobin A1c (HbA1c, range 5.1% to 6.5%) participated. They underwent forearm vein biopsy to access sympathetic nerves for the quantification of NET by Western blot, oral glucose tolerance test (OGTT), euglycaemic hyperinsulinaemic clamp, echocardiography and assessments of whole‐body norepinephrine kinetics and muscle sympathetic nerve activity. Results Norepinephrine transporter expression was inversely associated with fasting plasma glucose (r = −0.62, P = 0.02), glucose area under the curve during OGTT (AUC0–120, r = −0.65, P = 0.02) and HbA1c (r = −0.67, P = 0.01), and positively associated with steady‐state glucose utilization during euglycaemic clamp (r = 0.58, P = 0.04). Moreover, NET expression was inversely related to left ventricular posterior wall dimensions (r = −0.64, P = 0.02) and heart rate (r = −0.55, P = 0.05). Indices of hyperinsulinaemia were not associated with NET expression. In stepwise linear regression analysis adjusted for age, body mass index and blood pressure, HbA1c was an independent inverse predictor of NET expression, explaining 45% of its variance. Conclusions Hyperglycaemia is associated with reduced peripheral NET expression. Further studies are required to identify the direction of causality.
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Affiliation(s)
- N E Straznicky
- Human Neurotransmitters Laboratory Baker IDI Heart & Diabetes Institute Melbourne Australia
| | - L Guo
- Human Neurotransmitters Laboratory Baker IDI Heart & Diabetes Institute Melbourne Australia
| | - S J Corcoran
- Human Neurotransmitters Laboratory Baker IDI Heart & Diabetes Institute Melbourne Australia
| | - M D Esler
- Human Neurotransmitters Laboratory Baker IDI Heart & Diabetes Institute Melbourne Australia
| | - S E Phillips
- Human Neurotransmitters Laboratory Baker IDI Heart & Diabetes Institute Melbourne Australia
| | - C I Sari
- Human Neurotransmitters Laboratory Baker IDI Heart & Diabetes Institute Melbourne Australia
| | - M T Grima
- Human Neurotransmitters Laboratory Baker IDI Heart & Diabetes Institute Melbourne Australia
| | - S Karapanagiotidis
- Alfred Baker Medical Unit Baker IDI Heart & Diabetes Institute Melbourne Australia
| | - C Y Wong
- Alfred Baker Medical Unit Baker IDI Heart & Diabetes Institute Melbourne Australia; Cardiology, Western Health University of Melbourne Melbourne Australia
| | - N Eikelis
- Human Neurotransmitters Laboratory Baker IDI Heart & Diabetes Institute Melbourne Australia
| | - J A Mariani
- Heart Failure Research Group Baker IDI Heart & Diabetes Institute Melbourne Australia; Faculty of Medicine, Nursing and Health Sciences Monash University Melbourne Australia
| | - D Kobayashi
- Human Neurotransmitters Laboratory Baker IDI Heart & Diabetes Institute Melbourne Australia
| | - J B Dixon
- Human Neurotransmitters Laboratory Baker IDI Heart & Diabetes Institute Melbourne Australia; Primary Health Care Monash University Melbourne Australia
| | - G W Lambert
- Human Neurotransmitters Laboratory Baker IDI Heart & Diabetes Institute Melbourne Australia; Faculty of Medicine, Nursing and Health Sciences Monash University Melbourne Australia
| | - E A Lambert
- Human Neurotransmitters Laboratory Baker IDI Heart & Diabetes Institute Melbourne Australia; Departments of Physiology Monash University Melbourne Australia; Departments of Physiology University of Melbourne Melbourne Australia
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Abstract
The global epidemic of obesity and its related disease in combination with robust physiological defence of intentional weight loss generates a pressing need for effective weight loss therapies. Bariatric surgery, which works very effectively at delivering substantial sustained weight loss, has been an enigma with respect to mechanism of action. Naive concepts of restriction and malabsorption do not explain the efficacy of the most commonly used bariatric procedures. This century has seen increased interest in unravelling the mystery of the mechanisms underlying surgery associated weight loss with a focus on integrative gastrointestinal (GI) physiology, gut-brain signalling, and beyond weight loss effects on metabolism. GI interventions, some very minor, can alter GI wall stretch and pressure receptors; a range of GI hormones affecting hunger and satiety; bile acid metabolism and signalling; the characteristics of GI microbiome; portal vein nutrient sensing; and circulating concentrations of amino acids. Understanding the mechanisms involved should present targets for less invasive effective therapies.
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Affiliation(s)
- J B Dixon
- Baker IDI Heart & Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia.
| | - E A Lambert
- Baker IDI Heart & Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia
| | - G W Lambert
- Baker IDI Heart & Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia
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Dixon JB, Lambert EA, Grima M, Rice T, Lambert GW, Straznicky NE. Fat-free mass loss generated with weight loss in overweight and obese adults: What may we expect? Diabetes Obes Metab 2015; 17:91-3. [PMID: 25200854 DOI: 10.1111/dom.12389] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 08/26/2014] [Accepted: 09/02/2014] [Indexed: 11/27/2022]
Abstract
There is concern that intentional weight loss may generate excessive loss of fat-free mass (FFM). Idealists target minimal loss of FFM, while others consider that FFM loss of up to 25% of weight loss is acceptable. In a cross-sectional study of 275 weight-stable, overweight or obese adults, we used whole-body dual-energy X-ray absorptiometry to measure FFM. A range of models was used to estimate the expected ΔFFM/Δweight ratio required to attain the body composition of a weight-stable individual at a lower body mass index (BMI). Higher BMI was associated linearly with higher FFM in men and women. Proportional ΔFFM/Δweight was influenced by sex, BMI and age. Direct scatter plot analysis, quadratic curve fit modelling and linear FFM-BMI modelling provided similar estimates for each model of ΔFFM/Δweight ratio, with 40% for men and 33% for women. These results show that the 25% rule is inappropriate and our estimates are higher than those generally reported after intentional weight loss indicating favourable preservation of FFM.
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Affiliation(s)
- J B Dixon
- Clinical Obesity Research, Baker IDI Heart & Diabetes Institute, Melbourne, Australia; Primary Care Research Unit, Monash University, Melbourne, Australia
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Flavell CR, Lambert EA, Winters BD, Bredy TW. Mechanisms governing the reactivation-dependent destabilization of memories and their role in extinction. Front Behav Neurosci 2013; 7:214. [PMID: 24421762 PMCID: PMC3872723 DOI: 10.3389/fnbeh.2013.00214] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 12/13/2013] [Indexed: 12/28/2022] Open
Abstract
The extinction of learned associations has traditionally been considered to involve new learning, which competes with the original memory for control over behavior. However, a recent resurgence of interest in reactivation-dependent amnesia has revealed that the retrieval of fear-related memory (with what is essentially a brief extinction session) can result in its destabilization. This review discusses some of the cellular and molecular mechanisms that are involved in the destabilization of a memory following its reactivation and/or extinction, and investigates the evidence that extinction may involve both new learning as well as a partial destabilization-induced erasure of the original memory trace.
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Affiliation(s)
- Charlotte R Flavell
- Queensland Brain Institute, The University of Queensland Brisbane, QLD, Australia
| | - Elliot A Lambert
- Queensland Brain Institute, The University of Queensland Brisbane, QLD, Australia
| | - Boyer D Winters
- Department of Psychology, University of Guelph Guelph, ON, Canada
| | - Timothy W Bredy
- Queensland Brain Institute, The University of Queensland Brisbane, QLD, Australia
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Straznicky NE, Lambert EA, Grima MT, Eikelis N, Nestel PJ, Dawood T, Schlaich MP, Masuo K, Chopra R, Sari CI, Dixon JB, Tilbrook AJ, Lambert GW. The effects of dietary weight loss with or without exercise training on liver enzymes in obese metabolic syndrome subjects. Diabetes Obes Metab 2012; 14:139-48. [PMID: 21923735 DOI: 10.1111/j.1463-1326.2011.01497.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
AIM Insulin resistance and visceral adiposity are predisposing factors for fatty liver disease. The main objectives of this study were (i) to compare the effects of caloric restriction (CR) alone or together with moderate-intensity aerobic exercise training (CR+EX) on liver enzymes, a surrogate marker of liver injury, in obese metabolic syndrome (MetS) subjects and (ii) to identify anthropometric, metabolic, cardiovascular and dietary predictors of changes in liver enzymes. METHODS Sedentary men and women (n = 63), aged 55 ± 6 (s.d.) years with body mass index 32.7 ± 4.1 kg/m(2) and confirmed MetS, were randomized to 12-week CR, CR+EX or no treatment (Control). RESULTS Weight loss averaged 7.6% in the CR and 9.1% in the CR+EX group (time effect, p < 0.001; group effect, p = 0.11); insulin sensitivity improved by 49 and 45%, respectively (both p < 0.001). Fitness (maximal oxygen consumption) increased by 19% in the CR+EX group only (p < 0.001). Alanine aminotransferase (ALT) levels decreased by 20% in the CR and 24% in the CR+EX group (time effect, both p < 0.001; group effect, p = 0.68); corresponding values for γ-glutamyltransferase (GGT) were -28 and -33%, respectively (time effect, both p < 0.001; group effect, p = 0.28). Reduction in abdominal fat mass (measured by DXA from L1 to L4) independently predicted ΔALT (r = 0.42, p = 0.005) and ΔGGT (r = 0.55, p < 0.001), whereas change in dietary saturated fat intake was independently associated with ΔALT (r = 0.35, p = 0.03). CONCLUSIONS Reductions in central adiposity and saturated fat intake are key drivers of improvement in liver enzymes during lifestyle interventions. Exercise training did not confer significant incremental benefits in this study.
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Affiliation(s)
- N E Straznicky
- Laboratories of Human Neurotransmitters, Baker IDI Heart & Diabetes Institute, Melbourne, Victoria, Australia.
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Abstract
Nicotiana glauca, wild tree tobacco, induces arthrogrypotic congenital defects in piglets similar to those induced by Nicotiana tabacum, common tobacco. The present work was conducted to isolate the principal alkaloid of N. glauca, anabasine, in large quantity and good purity and to test the teratogenicity of the compound in pigs. The isolated compound was established to be anabasine and to be of suitable purity by chemical characterization. It proved to be teratogenic. Typical arthrogrypotic defects were induced in 21 of 26 offspring (three of three litters) when dams ingested 2.6 mg of the compound per kg body weight twice daily during the 43rd-53rd days of gestation. Of three dams dosed with 1.66 g/kg/day of the dried plant material during the 43rd-53rd days, one delivered deformed offspring representing one-third of all offspring in that group. These arthrogrypotic defects induced by anabasine were indistinguishable clinically from defects induced by either N. glauca or N. tabacum. In addition, anabasine at a dose of 2.6 mg/kg twice daily or N. glauca plant material at 1.66 gm/kg daily induced cleft palate in over three-fourths of offspring (100% of litters) when dams ingested either during the 30th-37th days of gestation or during longer periods that included those days.
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