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Whole Exome Sequencing Study Identifies Novel Rare Risk Variants for Habitual Coffee Consumption Involved in Olfactory Receptor and Hyperphagia. Nutrients 2022; 14:nu14204330. [PMID: 36297015 PMCID: PMC9607528 DOI: 10.3390/nu14204330] [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: 09/17/2022] [Revised: 10/13/2022] [Accepted: 10/13/2022] [Indexed: 11/06/2022] Open
Abstract
Habitual coffee consumption is an addictive behavior with unknown genetic variations and has raised public health issues about its potential health-related outcomes. We performed exome-wide association studies to identify rare risk variants contributing to habitual coffee consumption utilizing the newly released UK Biobank exome dataset (n = 200,643). A total of 34,761 qualifying variants were imported into SKAT to conduct gene-based burden and robust tests with minor allele frequency <0.01, adjusting the polygenic risk scores (PRS) of coffee intake to exclude the effect of common coffee-related polygenic risk. The gene-based burden and robust test of the exonic variants found seven exome-wide significant associations, such as OR2G2 (PSKAT = 1.88 × 10−9, PSKAT-Robust = 2.91 × 10−17), VEZT1 (PSKAT = 3.72 × 10−7, PSKAT-Robust = 1.41 × 10−7), and IRGC (PSKAT = 2.92 × 10−5, PSKAT-Robust = 1.07 × 10−7). These candidate genes were verified in the GWAS summary data of coffee intake, such as rs12737801 (p = 0.002) in OR2G2, and rs34439296 (p = 0.008) in IRGC. This study could help to extend genetic insights into the pathogenesis of coffee addiction, and may point to molecular mechanisms underlying health effects of habitual coffee consumption.
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Converging vulnerability factors for compulsive food and drug use. Neuropharmacology 2021; 196:108556. [PMID: 33862029 DOI: 10.1016/j.neuropharm.2021.108556] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 03/29/2021] [Accepted: 04/03/2021] [Indexed: 12/12/2022]
Abstract
Highly palatable foods and substance of abuse have intersecting neurobiological, metabolic and behavioral effects relevant for understanding vulnerability to conditions related to food (e.g., obesity, binge eating disorder) and drug (e.g., substance use disorder) misuse. Here, we review data from animal models, clinical populations and epidemiological evidence in behavioral, genetic, pathophysiologic and therapeutic domains. Results suggest that consumption of highly palatable food and drugs of abuse both impact and conversely are regulated by metabolic hormones and metabolic status. Palatable foods high in fat and/or sugar can elicit adaptation in brain reward and withdrawal circuitry akin to substances of abuse. Intake of or withdrawal from palatable food can impact behavioral sensitivity to drugs of abuse and vice versa. A robust literature suggests common substrates and roles for negative reinforcement, negative affect, negative urgency, and impulse control deficits, with both highly palatable foods and substances of abuse. Candidate genetic risk loci shared by obesity and alcohol use disorders have been identified in molecules classically associated with both metabolic and motivational functions. Finally, certain drugs may have overlapping therapeutic potential to treat obesity, diabetes, binge-related eating disorders and substance use disorders. Taken together, data are consistent with the hypotheses that compulsive food and substance use share overlapping, interacting substrates at neurobiological and metabolic levels and that motivated behavior associated with feeding or substance use might constitute vulnerability factors for one another. This article is part of the special issue on 'Vulnerabilities to Substance Abuse'.
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Liu J, Wang X, Ma R, Li T, Guo G, Ning B, Moran TH, Smith WW. AMPK signaling mediates synphilin-1-induced hyperphagia and obesity in Drosophila. J Cell Sci 2021; 134:jcs247742. [PMID: 33443093 PMCID: PMC7875497 DOI: 10.1242/jcs.247742] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 12/15/2020] [Indexed: 12/31/2022] Open
Abstract
Expression of synphilin-1 in neurons induces hyperphagia and obesity in a Drosophila model. However, the molecular pathways underlying synphilin-1-linked obesity remain unclear. Here, Drosophila models and genetic tools were used to study the synphilin-1-linked pathways in energy balance by combining molecular biology and pharmacological approaches. We found that expression of human synphilin-1 in flies increased AMP-activated kinase (AMPK) phosphorylation at Thr172 compared with that in non-transgenic flies. Knockdown of AMPK reduced AMPK phosphorylation and food intake in non-transgenic flies, and further suppressed synphilin-1-induced AMPK phosphorylation, hyperphagia, fat storage and body weight gain in transgenic flies. Expression of constitutively activated AMPK significantly increased food intake and body weight gain in non-transgenic flies, but it did not alter food intake in the synphilin-1 transgenic flies. In contrast, expression of dominant-negative AMPK reduced food intake in both non-transgenic and synphilin-1 transgenic flies. Treatment with STO-609 also suppressed synphilin-1-induced AMPK phosphorylation, hyperphagia and body weight gain. These results demonstrate that the AMPK signaling pathway plays a critical role in synphilin-1-induced hyperphagia and obesity. These findings provide new insights into the mechanisms of synphilin-1-controlled energy homeostasis.
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Affiliation(s)
- Jingnan Liu
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA
| | - Xiaobo Wang
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Rui Ma
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA
| | - Tianxia Li
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA
| | - Gongbo Guo
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Bo Ning
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Timothy H Moran
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Wanli W Smith
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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Synphilin-1 Interacts with AMPK and Increases AMPK Phosphorylation. Int J Mol Sci 2020; 21:ijms21124352. [PMID: 32570982 PMCID: PMC7352261 DOI: 10.3390/ijms21124352] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/08/2020] [Accepted: 06/09/2020] [Indexed: 01/16/2023] Open
Abstract
A role for the cytoplasmic protein synphilin-1 in regulating energy balance has been demonstrated recently. Expression of synphilin-1 increases ATP levels in cultured cells. However, the mechanism by which synphilin-1 alters cellular energy status is unknown. Here, we used cell models and biochemical approaches to investigate the cellular functions of synphilin-1 on the AMP-activated protein kinase (AMPK) signaling pathway, which may affect energy balance. Overexpression of synphilin-1 increased AMPK phosphorylation (activation). Moreover, synphilin-1 interacted with AMPK by co-immunoprecipitation and GST (glutathione S-transferase) pull-down assays. Knockdown of synphilin-1 reduced AMPK phosphorylation. Overexpression of synphilin-1 also altered AMPK downstream signaling, i.e., a decrease in acetyl CoA carboxylase (ACC) phosphorylation, and an increase in p70S6K phosphorylation. Treatment of compound C (an AMPK inhibitor) reduced synphilin-1 binding with AMPK. In addition, compound C diminished synphilin-1-induced AMPK phosphorylation, and the increase in cellular ATP (adenosine triphosphate) levels. Our results demonstrated that synphilin-1 couples with AMPK, and they exert mutual effects on each other to regulate cellular energy status. These findings not only identify novel cellular actions of synphilin-1, but also provide new insights into the roles of synphilin-1 in regulating energy currency, ATP.
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Genomic dissection and prediction of feed intake and residual feed intake traits using a longitudinal model in F2 chickens. Animal 2017; 12:1792-1798. [PMID: 29268803 DOI: 10.1017/s1751731117003354] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Feed efficiency traits (FETs) are important economic indicators in poultry production. Because feed intake (FI) is a time-dependent variable, longitudinal models can provide insights into the genetic basis of FET variation over time. It is expected that the application of longitudinal models as part of genome-wide association (GWA) and genomic selection (i.e. genome-wide selection (GS)) studies will lead to an increase in accuracy of selection. Thus, the objectives of this study were to evaluate the accuracy of estimated breeding values (EBVs) based on pedigree as well as high-density single nucleotide polymorphism (SNP) genotypes, and to conduct a GWA study on longitudinal FI and residual feed intake (RFI) in a total of 312 chickens with phenotype and genotype in the F2 population. The GWA and GS studies reported in this paper were conducted using β-spline random regression models for FI and RFI traits in a chicken F2 population, with FI and BW recorded for each bird weekly between 2 and 10 weeks of age. A single SNP regression approach was used on spline coefficients for weekly FI and RFI traits, with results showing that two significant SNPs for FI occur in the synuclein (SNCAIP) gene. Results also show that these regions are significantly associated with the spline coefficients (q 2) for 5- and 6-week-old birds, while GWA study results showed no SNP association with RFI in F2 chickens. Estimated breeding value predictions obtained using a pedigree-based best linear unbiased prediction (ABLUP) model were then compared with predictions based on genomic best linear unbiased prediction (GBLUP). The accuracy was measured as correlation between genomic EBV and EBV with the phenotypic value corrected for fixed effects divided by the square root of heritability. The regression of observed on predicted values was used to estimate bias of methods. Results show that prediction accuracies using GBLUP and ABLUP for the FI measured from 2nd to 10th week were between 0.06 and 0.46 and 0.03 and 0.37, respectively. These results demonstrate that genomic methods are able to increase the accuracy of predicted breeding values at later ages on the basis of both traits, and indicate that use of a longitudinal model can improve selection accuracy for the trajectory of traits in F2 chickens when compared with conventional methods.
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Szargel R, Shani V, Abd Elghani F, Mekies LN, Liani E, Rott R, Engelender S. The PINK1, synphilin-1 and SIAH-1 complex constitutes a novel mitophagy pathway. Hum Mol Genet 2016; 25:3476-3490. [DOI: 10.1093/hmg/ddw189] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023] Open
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Abstract
Previously, we have identified a novel role for the cytoplasmic protein, synphilin-1(SP1), in the controls of food intake and body weight in both mice and Drosophila. Ubiquitous overexpression of human SP1 in brain neurons in transgenic mice results in hyperphagia expressed as an increase in meal size. However, the mechanisms underlying this action of SP1 remain to be determined. Here we investigate a potential role for altered gut feedback signaling in the effects of SP1 on food intake. We examined responses to peripheral administration of cholecytokinin (CCK), amylin, and the glucagon like peptide-1 (GLP-1) receptor agonist, exendin-4. Intraperitoneal administration of CCK at doses ranging from 1–10 nmol/kg significantly reduced glucose intake in wild type (WT) mice, but failed to affect intake in SP1 transgenic mice. Moreover, there was a significant attenuation of CCK-induced c-Fos expression in the dorsal vagal complex in SP1 transgenic mice. In contrast, WT and SP1 transgenic mice were similarly responsive to both amylin and exendin-4 treatment. These studies demonstrate that SP1 results in a CCK response deficiency that may contribute to the increased meal size and overall hyperphagia in synphillin-1 transgenic mice.
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Larsen K, Madsen LB, Farajzadeh L, Bendixen C. Splicing variants of porcine synphilin-1. Meta Gene 2015; 5:32-42. [PMID: 26101749 PMCID: PMC4468357 DOI: 10.1016/j.mgene.2015.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 04/29/2015] [Accepted: 04/30/2015] [Indexed: 11/24/2022] Open
Abstract
Parkinson's disease (PD), idiopathic and familial, is characterized by degradation of dopaminergic neurons and the presence of Lewy bodies (LB) in the substantia nigra. LBs contain aggregated proteins of which α-synuclein is the major component. The protein synphilin-1 interacts and colocalizes with α-synuclein in LBs. The aim of this study was to isolate and characterize porcine synphilin-1 and isoforms hereof with the future perspective to use the pig as a model for Parkinson's disease. The porcine SNCAIP cDNA was cloned by reverse transcriptase PCR. The spatial expression of SNCAIP mRNA was investigated by RNAseq. The presented work reports the molecular cloning and characterization of the porcine (Sus scrofa) synphilin-1 cDNA (SNCAIP) and three splice variants hereof. The porcine SNCAIP cDNA codes for a protein (synphilin-1) of 919 amino acids which shows a high similarity to human (90%) and to mouse (84%) synphilin-1. Three shorter transcript variants of the synphilin-1 gene were identified, all lacking one or more exons. SNCAIP transcripts were detected in most examined organs and tissues and the highest expression was found in brain tissues and lung. Conserved splicing variants and a novel splice form of synhilin-1 were found in this study. All synphilin-1 isoforms encoded by the identified transcript variants lack functional domains important for protein degradation. The full-length porcine SNCAIP cDNA encoding synphilin-1 was cloned and characterized. Three splicing variants of synphilin-1 were identified. Both conserved and novel splicing variant were found. SNCAIP mRNA was differently expressed in analyzed tissues and organs with highest expression in brain tissue and lung.
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Affiliation(s)
- Knud Larsen
- Department of Molecular Biology and Genetics, Aarhus University, Blichers Allé 20, P.O. Box 50, DK-8830 Tjele, Denmark
| | - Lone Bruhn Madsen
- Department of Molecular Biology and Genetics, Aarhus University, Blichers Allé 20, P.O. Box 50, DK-8830 Tjele, Denmark
| | - Leila Farajzadeh
- Department of Molecular Biology and Genetics, Aarhus University, Blichers Allé 20, P.O. Box 50, DK-8830 Tjele, Denmark
| | - Christian Bendixen
- Department of Molecular Biology and Genetics, Aarhus University, Blichers Allé 20, P.O. Box 50, DK-8830 Tjele, Denmark
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Li T, Liu J, Smith WW. Synphilin-1 binds ATP and regulates intracellular energy status. PLoS One 2014; 9:e115233. [PMID: 25545246 PMCID: PMC4278857 DOI: 10.1371/journal.pone.0115233] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 11/19/2014] [Indexed: 11/19/2022] Open
Abstract
Recent studies have suggested that synphilin-1, a cytoplasmic protein, is involved in energy homeostasis. Overexpression of synphilin-1 in neurons results in hyperphagia and obesity in animal models. However, the mechanism by which synphilin-1 alters energy homeostasis is unknown. Here, we used cell models and biochemical approaches to investigate the cellular functions of synphilin-1 that may affect energy balance. Synphilin-1 was pulled down by ATP-agarose beads, and the addition of ATP and ADP reduced this binding, indicating that synphilin-1 bound ADP and ATP. Synphilin-1 also bound GMP, GDP, and GTP but with a lower affinity than it bound ATP. In contrast, synphilin-1 did not bind with CTP. Overexpression of synphilin-1 in HEK293T cells significantly increased cellular ATP levels. Genetic alteration to abolish predicted ATP binding motifs of synphilin-1 or knockdown of synphilin-1 by siRNA reduced cellular ATP levels. Together, these data demonstrate that synphilin-1 binds and regulates the cellular energy molecule, ATP. These findings provide a molecular basis for understanding the actions of synphilin-1 in energy homeostasis.
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Affiliation(s)
- Tianxia Li
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland 21201, United States of America
| | - Jingnan Liu
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland 21201, United States of America
| | - Wanli W. Smith
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland 21201, United States of America
- * E-mail:
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Li X, Treesukosol Y, Moghadam A, Smith M, Ofeldt E, Yang D, Li T, Tamashiro K, Choi P, Moran TH, Smith WW. Behavioral characterization of the hyperphagia synphilin-1 overexpressing mice. PLoS One 2014; 9:e91449. [PMID: 24829096 PMCID: PMC4020742 DOI: 10.1371/journal.pone.0091449] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 02/12/2014] [Indexed: 01/06/2023] Open
Abstract
Synphilin-1 is a cytoplasmic protein that has been shown to be involved in the control of energy balance. Previously, we reported on the generation of a human synphilin-1 transgenic mouse model (SP1), in which overexpression of human synphilin-1 resulted in hyperphagia and obesity. Here, behavioral measures in SP1 mice were compared with those of their age-matched controls (NTg) at two time points: when there was not yet a group body weight difference (“pre-obese”) and when SP1 mice were heavier (“obese”). At both time points, meal pattern analyses revealed that SP1 mice displayed higher daily chow intake than non-transgenic control mice. Furthermore, there was an increase in meal size in SP1 mice compared with NTg control mice at the obese stage. In contrast, there was no meal number change between SP1 and NTg control mice. In a brief-access taste procedure, both “pre-obese” and “obese“ SP1 mice displayed concentration-dependent licking across a sucrose concentration range similar to their NTg controls. However, at the pre-obese stage, SP1 mice initiated significantly more trials to sucrose across the testing sessions and licked more vigorously at the highest concentration presented, than the NTg counterparts. These group differences in responsiveness to sucrose were no longer apparent in obese SP1 mice. These results suggest that at the pre-obese stage, the increased trials to sucrose in the SP1 mice reflects increased appetitive behavior to sucrose that may be indicative of the behavioral changes that may contribute to hyperphagia and development of obesity in SP1 mice. These studies provide new insight into synphilin-1 contributions to energy homeostasis.
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Affiliation(s)
- Xueping Li
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland, United States of America
| | - Yada Treesukosol
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Alexander Moghadam
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Megan Smith
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Erica Ofeldt
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Dejun Yang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland, United States of America
| | - Tianxia Li
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland, United States of America
| | - Kellie Tamashiro
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Pique Choi
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Timothy H. Moran
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (WWS); (THM)
| | - Wanli W. Smith
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland, United States of America
- * E-mail: (WWS); (THM)
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Smith WW, Thomas J, Liu J, Li T, Moran TH. From fat fruit fly to human obesity. Physiol Behav 2014; 136:15-21. [PMID: 24508822 DOI: 10.1016/j.physbeh.2014.01.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 01/13/2014] [Accepted: 01/27/2014] [Indexed: 12/31/2022]
Abstract
Obesity is a chronic metabolic disease that has become a global problem. Although a tremendous amount of effort has been spent to prevent and treat obesity, its etiology is still largely unknown and there are not yet sufficient strategies to control obesity. Recently, the fruit fly, Drosophila melanogaster, has become a useful model for studying metabolic homeostasis and obesity related disorders. The goal of this mini-review is to summarize the recent achievements of Drosophila models and to highlight the experimental protocols used in studying feeding behavior and energy homeostasis in the fly. The Drosophila models provide useful tools to understand obesity pathogenesis and to develop novel therapeutics.
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Affiliation(s)
- Wanli W Smith
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA.
| | - Joseph Thomas
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA
| | - Jingnan Liu
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA
| | - Tianxia Li
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA
| | - Timothy H Moran
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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Abstract
AIMS The pathogenesis of obesity remains incompletely understood. Drosophila have conserved neuroendocrine and digestion systems with human and become an excellent system for studying energy homeostasis. Here, we reported a novel obesity Drosophila model, in which expression of human protein, synphilin-1 (SP1), in neurons fosters positive energy balance. SUBJECTS AND METHODS To further understand the actions of SP1 in energy balance control, the upstream activation sequence UAS/GAL4 system was used to generate human SP1 transgenic Drosophila. We characterized a human SP1 transgenic Drosophila by assessing SP1 expression, fat lipid deposition, food intake and fly locomotor activity to determine the major behavioral changes and their consequences in the development of the obesity-like phenotype. RESULTS Overexpression of SP1 in neurons, but not peripheral cells, increased the body weight of flies compared with that of non-transgenic controls. SP1 increased food intake but did not affect locomotor activity. SP1 increased the levels of triacylglycerol, and the size of fat body cells and lipid droplets, indicating that SP1 increased lipid-fat disposition. Survival studies showed that SP1 transgenic flies were more resistant to food deprivation. SP1 regulated lipin gene expression that may participate in SP1-induced fat deposition and starvation resistance. CONCLUSION These studies demonstrate that SP1 expression affects energy homeostasis in ways that enhance positive energy balance and provide a useful obesity model for future pathogenesis and therapeutic studies.
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