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Ritter ML, Wagner VA, Balapattabi K, Opichka MA, Lu KT, Wackman KK, Reho JJ, Keen HL, Kwitek AE, Morselli LL, Geurts AM, Sigmund CD, Grobe JL. Krüppel-like factor 4 in transcriptional control of the three unique isoforms of Agouti-related peptide in mice. Physiol Genomics 2024; 56:265-275. [PMID: 38145289 PMCID: PMC10866620 DOI: 10.1152/physiolgenomics.00042.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 11/15/2023] [Accepted: 12/21/2023] [Indexed: 12/26/2023] Open
Abstract
Agouti-related peptide (AgRP/Agrp) within the hypothalamic arcuate nucleus (ARC) contributes to the control of energy balance, and dysregulated Agrp may contribute to metabolic adaptation during prolonged obesity. In mice, three isoforms of Agrp are encoded via distinct first exons. Agrp-A (ENSMUST00000005849.11) contributed 95% of total Agrp in mouse ARC, whereas Agrp-B (ENSMUST00000194654.2) dominated in placenta (73%). Conditional deletion of Klf4 from Agrp-expressing cells (Klf4Agrp-KO mice) reduced Agrp mRNA and increased energy expenditure but had no effects on food intake or the relative abundance of Agrp isoforms in the ARC. Chronic high-fat diet feeding masked these effects of Klf4 deletion, highlighting the context-dependent contribution of KLF4 to Agrp control. In the GT1-7 mouse hypothalamic cell culture model, which expresses all three isoforms of Agrp (including Agrp-C, ENSMUST00000194091.6), inhibition of extracellular signal-regulated kinase (ERK) simultaneously increased KLF4 binding to the Agrp promoter and stimulated Agrp expression. In addition, siRNA-mediated knockdown of Klf4 reduced expression of Agrp. We conclude that the expression of individual isoforms of Agrp in the mouse is dependent upon cell type and that KLF4 directly promotes the transcription of Agrp via a mechanism that is superseded during obesity.NEW & NOTEWORTHY In mice, three distinct isoforms of Agouti-related peptide are encoded via distinct first exons. In the arcuate nucleus of the hypothalamus, Krüppel-like factor 4 stimulates transcription of the dominant isoform in lean mice, but this mechanism is altered during diet-induced obesity.
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Affiliation(s)
- McKenzie L Ritter
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Valerie A Wagner
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Genetics Graduate Program, University of Iowa, Iowa City, Iowa, United States
| | - Kirthikaa Balapattabi
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Megan A Opichka
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Ko-Ting Lu
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Kelsey K Wackman
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - John J Reho
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Henry L Keen
- Bioinformatics Division, Institute of Human Genetics, University of Iowa, Iowa City, Iowa, United States
| | - Anne E Kwitek
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Linda T. and John A. Mellowes Center for Genomic Sciences and Precision Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Lisa L Morselli
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Division of Endocrinology and Molecular Medicine, Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Aron M Geurts
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Linda T. and John A. Mellowes Center for Genomic Sciences and Precision Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Curt D Sigmund
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Justin L Grobe
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
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Zapata RC, Zhang D, Libster A, Porcu A, Montilla-Perez P, Nur A, Xu B, Zhang Z, Correa SM, Liu C, Telese F, Osborn O. Nuclear receptor 5A2 regulation of Agrp underlies olanzapine-induced hyperphagia. Mol Psychiatry 2023; 28:1857-1867. [PMID: 36765131 PMCID: PMC10412731 DOI: 10.1038/s41380-023-01981-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 01/18/2023] [Accepted: 01/24/2023] [Indexed: 02/12/2023]
Abstract
Antipsychotic (AP) drugs are efficacious treatments for various psychiatric disorders, but excessive weight gain and subsequent development of metabolic disease remain serious side effects of their use. Increased food intake leads to AP-induced weight gain, but the underlying molecular mechanisms remain unknown. In previous studies, we identified the neuropeptide Agrp and the transcription factor nuclear receptor subfamily 5 group A member 2 (Nr5a2) as significantly upregulated genes in the hypothalamus following AP-induced hyperphagia. While Agrp is expressed specifically in the arcuate nucleus of the hypothalamus and plays a critical role in appetite stimulation, Nr5a2 is expressed in both the CNS and periphery, but its role in food intake behaviors remains unknown. In this study, we investigated the role of hypothalamic Nr5a2 in AP-induced hyperphagia and weight gain. In hypothalamic cell lines, olanzapine treatment resulted in a dose-dependent increase in gene expression of Nr5a2 and Agrp. In mice, the pharmacological inhibition of NR5A2 decreased olanzapine-induced hyperphagia and weight gain, while the knockdown of Nr5a2 in the arcuate nucleus partially reversed olanzapine-induced hyperphagia. Chromatin-immunoprecipitation studies showed for the first time that NR5A2 directly binds to the Agrp promoter region. Lastly, the analysis of single-cell RNA seq data confirms that Nr5a2 and Agrp are co-expressed in a subset of neurons in the arcuate nucleus. In summary, we identify Nr5a2 as a key mechanistic driver of AP-induced food intake. These findings can inform future clinical development of APs that do not activate hyperphagia and weight gain.
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Affiliation(s)
- Rizaldy C Zapata
- Division of Endocrinology and Metabolism, Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Dinghong Zhang
- Division of Endocrinology and Metabolism, Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Avraham Libster
- Division of Endocrinology and Metabolism, Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Alessandra Porcu
- Department of Psychiatry, University of California San Diego, La Jolla, CA, 92093, USA
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, Columbia, SC, 29208, USA
| | | | - Aisha Nur
- Department of Psychiatry, University of California San Diego, La Jolla, CA, 92093, USA
| | - Baijie Xu
- Center for Hypothalamic Research, Departments of Internal Medicine and Neuroscience, Peter O'Donnell Jr. Brain Institute, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Zhi Zhang
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Stephanie M Correa
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Chen Liu
- Center for Hypothalamic Research, Departments of Internal Medicine and Neuroscience, Peter O'Donnell Jr. Brain Institute, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Francesca Telese
- Department of Psychiatry, University of California San Diego, La Jolla, CA, 92093, USA
| | - Olivia Osborn
- Division of Endocrinology and Metabolism, Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA.
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3
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Lin CY, Yeh KY, Lai HH, Her GM. AgRP Neuron-Specific Ablation Represses Appetite, Energy Intake, and Somatic Growth in Larval Zebrafish. Biomedicines 2023; 11:biomedicines11020499. [PMID: 36831035 PMCID: PMC9953713 DOI: 10.3390/biomedicines11020499] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/01/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Neuronal circuits regulating appetite are dominated by arcuate nucleus neurons, which include appetite-promoting and -suppressing neurons that release the orexigenic neuropeptide agouti-related protein (AgRP) and anorexigenic neuropeptide pro-opiomelanocortin, respectively, to compete for melanocortin receptors to modulate feeding behavior. In this study, we expressed novel agrp promoters, including different lengths of the 5' flanking regions of the agrp gene (4749 bp) in the zebrafish genome. We used the agrp promoter to derive the enhanced green fluorescent protein (EGFP)-nitroreductase (NTR) fusion protein, allowing expression of the green fluorescence signal in the AgRP neurons. Then, we treated the transgenic zebrafish AgRP4.7NTR (Tg [agrp-EGFP-NTR]) with metronidazole to ablate the AgRP neurons in the larvae stage and observed a decline in their appetite and growth. The expression of most orexigenic and growth hormone/insulin-like growth factor axis genes decreased, whereas that of several anorexigenic genes increased. Our findings demonstrate that AgRP is a critical regulator of neuronal signaling for zebrafish appetite and energy intake control. Thus, AgRP4.7NTR can be used as a drug-screening platform for therapeutic targets to treat human appetite disorders, including obesity. Furthermore, the unique agrp promoter we identified can be a powerful tool for research on AgRP neurons, especially AgRP neuron-mediated pathways in the hypothalamus, and appetite.
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Affiliation(s)
- Chiu-Ya Lin
- Department of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung City 202, Taiwan
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Kun-Yun Yeh
- Division of Hemato-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Keelung City 204, Taiwan
| | - Hsin-Hung Lai
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Guor Mour Her
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
- Correspondence: ; Tel.: +886-2-2826-7000 (ext. 67990)
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Xu KJ, Loganathan N, Belsham DD. Bisphenol S induces Agrp expression through GPER1 activation and alters transcription factor expression in immortalized hypothalamic neurons: A mechanism distinct from BPA-induced upregulation. Mol Cell Endocrinol 2022; 552:111630. [PMID: 35569583 DOI: 10.1016/j.mce.2022.111630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 03/09/2022] [Accepted: 03/25/2022] [Indexed: 11/22/2022]
Abstract
The increasing prevalence of obesity around the world has brought concern upon ubiquitously present obesogenic environmental compounds, such as bisphenol A (BPA). Increasingly tightened regulations on the industrial use of BPA have prompted a transition to a structurally similar alternative, bisphenol S (BPS). BPS displays endocrine-disrupting behaviours similar to those of BPA and increases body weight, food intake and the hypothalamic expression of Agrp in vivo. However, the mechanisms behind this deleterious effect are unclear. Here, we report an increase in the mRNA level of Agrp at 4 h following BPS treatment in immortalized murine hypothalamic cell lines of embryonic and adult origin (mHypoE-41, mHypoA-59). BPS-induced changes in the expression of transcription factors and estrogen receptors that occurred concurrently with Agrp upregulation demonstrated similarities to BPA-induced changes, however, there were also changes that were unique to BPS. Specifically, while Chop, Atf3, Atf4, Atf6, Klf4, and Creb1 were upregulated and Gper1 was downregulated by both BPA and BPS, Esr1 mRNA levels were upregulated and Foxo1 and Stat3 levels remained unchanged by BPS. Finally, inhibition of GPER1 by G15 prevented BPS-mediated Agrp upregulation, independent of Atf3 and Klf4 upregulation. Overall, our results demonstrate the ability of BPS to increase Agrp mRNA expression through GPER1 signaling and to alter transcription factor expression in hypothalamic neurons, further elucidating the endocrine-disrupting potential of this alternative industrial chemical.
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Affiliation(s)
- Katherine J Xu
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Neruja Loganathan
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Denise D Belsham
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Obstetrics and Gynaecology, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
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5
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Loganathan N, McIlwraith EK, Belsham DD. Bisphenol A Induces Agrp Gene Expression in Hypothalamic Neurons through a Mechanism Involving ATF3. Neuroendocrinology 2021; 111:678-695. [PMID: 32575098 DOI: 10.1159/000509592] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 06/22/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND Bisphenol A (BPA) is a ubiquitous endocrine disrupting chemical and obesogen. Although limited evidence exists of the effects of BPA on hypothalamic agouti-related peptide (AgRP) levels, the mechanisms underlying these effects remain unknown. Given that AgRP is a potent orexigenic neuropeptide, determining the mechanism by which BPA increases AgRP is critical to preventing the progression to metabolic disease. METHODS Using quantitative reverse transcriptase polymerase chain reaction, we investigated the response of Agrp-expressing mouse hypothalamic cell lines to BPA treatment. The percentage of total BPA entering hypothalamic cells in culture was quantified using an enzyme-linked immunosorbent assay. In order to identify the mechanism underlying BPA-mediated changes in Agrp, siRNA knockdown of transcription factors, FOXO1, CHOP, ATF3, ATF4, ATF6, and small-molecule inhibitors of endoplasmic reticulum stress, JNK or MEK/ERK were used. RESULTS BPA increased mRNA levels of Agrp in six hypothalamic cell lines (mHypoA-59, mHypoE-41, mHypoA-2/12, mHypoE-46, mHypoE-44, and mHypoE-42). Interestingly, only 18% of the total BPA in the culture medium entered the cells after 24 h, suggesting that the exposure concentration is much lower than the treatment concentration. BPA increased pre-Agrp mRNA levels, indicating increased Agrp transcription. Knockdown of the transcription factor ATF3 prevented BPA-mediated increase in Agrp, pre-Agrp, and in part Npy mRNA levels. However, chemical chaperone, sodium phenylbutyrate, JNK inhibitor, SP600125, or the MEK/ERK inhibitor PD0352901 did not block BPA-induced Agrp upregulation. CONCLUSION Overall, these results indicate that hypothalamic Agrp is susceptible to dysregulation by BPA and implicate ATF3 as a common mediator of the orexigenic effects of BPA in hypothalamic neurons.
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Affiliation(s)
- Neruja Loganathan
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Emma K McIlwraith
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Denise D Belsham
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada,
- Department of Obstetrics and Gynaecology, University of Toronto, Toronto, Ontario, Canada,
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada,
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6
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Cheng Z, Yang W, Li B, Cui R. KLF4 Exerts Sedative Effects in Pentobarbital-Treated Mice. J Mol Neurosci 2021; 71:596-606. [PMID: 32789565 DOI: 10.1007/s12031-020-01680-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 08/05/2020] [Indexed: 10/23/2022]
Abstract
KLF4 is a zinc-finger transcription factor that plays an essential role in many biological processes, including neuroinflammation, neuron regeneration, cell proliferation, and apoptosis. Through effects on these processes, KLF4 has likely roles in Alzheimer's disease, Parkinson's disease, and traumatic brain injury. However, little is known about the role of KLF4 in more immediate behavioral processes that similarly depend upon broad changes in brain excitability, such as the sleep process. Here, behavioral approaches, western blot, and immunohistochemical experiments were used to explore the role of KLF4 on sedation and the potential mechanisms of those effects. The results showed that overexpression of KLF4 prolonged loss of righting reflex (LORR) duration in pentobarbital-treated mice and increased c-Fos expression in the lateral hypothalamus (LH) and the ventrolateral preoptic nucleus (VLPO), while it decreased c-Fos expression in the tuberomammillary nucleus (TMN). Moreover, overexpression of KLF4 reduced the expression of p53 in the hypothalamus and increased the expression of STAT3 in the hypothalamus. Therefore, these results suggest that KLF4 exerts sedative effects through the regulation of p53 and STAT3 expression, and it indicates a role of KLF4 ligands in the treatment of sleep disorders.
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7
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Subkhangulova A, Malik AR, Hermey G, Popp O, Dittmar G, Rathjen T, Poy MN, Stumpf A, Beed PS, Schmitz D, Breiderhoff T, Willnow TE. SORCS1 and SORCS3 control energy balance and orexigenic peptide production. EMBO Rep 2018; 19:embr.201744810. [PMID: 29440124 PMCID: PMC5891432 DOI: 10.15252/embr.201744810] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [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: 07/12/2017] [Revised: 01/15/2018] [Accepted: 01/22/2018] [Indexed: 12/20/2022] Open
Abstract
SORCS1 and SORCS3 are two related sorting receptors expressed in neurons of the arcuate nucleus of the hypothalamus. Using mouse models with individual or dual receptor deficiencies, we document a previously unknown function of these receptors in central control of metabolism. Specifically, SORCS1 and SORCS3 act as intracellular trafficking receptors for tropomyosin-related kinase B to attenuate signaling by brain-derived neurotrophic factor, a potent regulator of energy homeostasis. Loss of the joint action of SORCS1 and SORCS3 in mutant mice results in excessive production of the orexigenic neuropeptide agouti-related peptide and in a state of chronic energy excess characterized by enhanced food intake, decreased locomotor activity, diminished usage of lipids as metabolic fuel, and increased adiposity, albeit at overall reduced body weight. Our findings highlight a novel concept in regulation of the melanocortin system and the role played by trafficking receptors SORCS1 and SORCS3 in this process.
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Affiliation(s)
| | - Anna R Malik
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Guido Hermey
- Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Oliver Popp
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Gunnar Dittmar
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany
| | - Thomas Rathjen
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Matthew N Poy
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Alexander Stumpf
- Neuroscience Research Center, Charité - University Medicine, Berlin, Germany
| | - Prateep Sanker Beed
- Neuroscience Research Center, Charité - University Medicine, Berlin, Germany
| | - Dietmar Schmitz
- Neuroscience Research Center, Charité - University Medicine, Berlin, Germany
| | | | - Thomas E Willnow
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany .,Berlin Institute of Health, Berlin, Germany
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8
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Gan L, Liu Z, Luo D, Ren Q, Wu H, Li C, Sun C. Reduced Endoplasmic Reticulum Stress-Mediated Autophagy Is Required for Leptin Alleviating Inflammation in Adipose Tissue. Front Immunol 2017; 8:1507. [PMID: 29250056 PMCID: PMC5715390 DOI: 10.3389/fimmu.2017.01507] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 10/25/2017] [Indexed: 12/15/2022] Open
Abstract
Leptin is an adipocyte-derived hormone and maintains adipose function under challenged conditions. Autophagy is also essential to maintain cellular homeostasis and regulate characteristics of adipose tissue. However, the effects of leptin on autophagy of adipocyte remain elusive. Here, we demonstrated endoplasmic reticulum (ER) stress and leptin were correlated with autophagy and inflammation by transcriptome sequencing of adipose tissue. Leptin-mediated inhibition of autophagy was involved in upstream reduction of ER stress proteins such as Chop, GRP78, and Atf4, since blockage of autophagy using pharmacological approach had no effect on tunicamycin-induced ER stress. Moreover, we determined KLF4, the potential transcriptional factor of Atf4, was required for the leptin-mediated autophagy in the regulation of adipocyte inflammation. Importantly, ATF4 physically interacted with ATG5 and subsequently formed a complex to promote adipocyte autophagy. Further analysis revealed that Atg5, a core component of autophagosome, was the target for leptin-mediate autophagy. In addition, leptin alleviated ER stress-induced inflammation by reducing autophagy-mediated degradation of IκB in adipocytes. Exogenous leptin treatment also ameliorated autophagy and inflammation of white adipose tissue in ob/ob mice. Taken together, our results indicated that leptin inhibited ER stress-mediated autophagy and inflammation through the negatively regulation of Atf4/Atg5 complex in adipocytes. These findings identify a new potential means for intervention of autophagy to prevent or treat obese caused metabolic syndrome of mammals.
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Affiliation(s)
- Lu Gan
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Zhenjiang Liu
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Dan Luo
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Qian Ren
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Hua Wu
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Changxing Li
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Chao Sun
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
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9
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Nakajima KI, Cui Z, Li C, Meister J, Cui Y, Fu O, Smith AS, Jain S, Lowell BB, Krashes MJ, Wess J. Gs-coupled GPCR signalling in AgRP neurons triggers sustained increase in food intake. Nat Commun 2016; 7:10268. [PMID: 26743492 PMCID: PMC4729878 DOI: 10.1038/ncomms10268] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Accepted: 11/24/2015] [Indexed: 01/06/2023] Open
Abstract
Agouti-related peptide (AgRP) neurons of the hypothalamus play a key role in regulating food intake and body weight, by releasing three different orexigenic molecules: AgRP; GABA; and neuropeptide Y. AgRP neurons express various G protein-coupled receptors (GPCRs) with different coupling properties, including Gs-linked GPCRs. At present, the potential role of Gs-coupled GPCRs in regulating the activity of AgRP neurons remains unknown. Here we show that the activation of Gs-coupled receptors expressed by AgRP neurons leads to a robust and sustained increase in food intake. We also provide detailed mechanistic data linking the stimulation of this class of receptors to the observed feeding phenotype. Moreover, we show that this pathway is clearly distinct from other GPCR signalling cascades that are operative in AgRP neurons. Our data suggest that drugs able to inhibit this signalling pathway may become useful for the treatment of obesity. Hypothalamic Agouti-related peptide (AgRP) neurons play a key role in regulating food intake. Here, the authors report a novel pathway in which activation of Gs-coupled receptors on AgRP neurons leads to robust, sustained increase in food intake.
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Affiliation(s)
- Ken-ichiro Nakajima
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Zhenzhong Cui
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Chia Li
- Diabetes Endocrine and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Jaroslawna Meister
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Yinghong Cui
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Ou Fu
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 1138657, Japan
| | - Adam S Smith
- Section on Neural Gene Expression, National Institute of Mental Health, Bethesda, Maryland 20892, USA
| | - Shalini Jain
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Bradford B Lowell
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Michael J Krashes
- Diabetes Endocrine and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Jürgen Wess
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
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10
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Imbernon M, Sanchez-Rebordelo E, Gallego R, Gandara M, Lear P, Lopez M, Dieguez C, Nogueiras R. Hypothalamic KLF4 mediates leptin's effects on food intake via AgRP. Mol Metab 2014; 3:441-51. [PMID: 24944903 PMCID: PMC4060210 DOI: 10.1016/j.molmet.2014.04.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/01/2014] [Accepted: 04/02/2014] [Indexed: 11/18/2022] Open
Abstract
Krüppel-like factor 4 (KLF4) is a zinc-finger-type transcription factor expressed in a range of tissues that plays multiple functions. We report that hypothalamic KLF4 represents a new transcription factor specifically modulating agouti-related protein (AgRP) expression in vivo. Hypothalamic KLF4 colocalizes with AgRP neurons and is modulated by nutritional status and leptin. Over-expression of KLF4 in the hypothalamic arcuate nucleus (ARC) induces food intake and increases body weight through the specific stimulation of AgRP, as well as blunting leptin sensitivity in lean rats independent of forkhead box protein 01 (FoxO1). Down-regulation of KLF4 in the ARC inhibits fasting-induced food intake in both lean and diet-induced obese (DIO) rats. Silencing KLF4, however, does not, on its own, enhance peripheral leptin sensitivity in DIO rats.
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Affiliation(s)
- Monica Imbernon
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Estrella Sanchez-Rebordelo
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Rosalia Gallego
- Department of Morphological Sciences, School of Medicine, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain
| | - Marina Gandara
- Department of Morphological Sciences, School of Medicine, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain
| | - Pamela Lear
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain
| | - Miguel Lopez
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Carlos Dieguez
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
- Corresponding authors. Department of Physiology, Centro de Investigaciones Medicas de la Universidad de Santiago (CIMUS), University of Santiago de Compostela & CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Avenida de Barcelona s/n, 15782 Santiago de Compostela, A Coruña, Spain. Tel.: +34 881815437.
| | - Ruben Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
- Corresponding authors. Department of Physiology, Centro de Investigaciones Medicas de la Universidad de Santiago (CIMUS), University of Santiago de Compostela & CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Avenida de Barcelona s/n, 15782 Santiago de Compostela, A Coruña, Spain. Tel.: +34 881815437.
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Matzko ME, Argyropoulos G, Wood GC, Chu X, McCarter RJM, Still CD, Gerhard GS. Association of ghrelin receptor promoter polymorphisms with weight loss following Roux-en-Y gastric bypass surgery. Obes Surg 2012; 22:783-90. [PMID: 22411573 DOI: 10.1007/s11695-012-0631-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Ghrelin plays a role in appetite and has been hypothesized to play a role in the mechanism of Roux-en-Y gastric bypass (RYGB) surgery. Single nucleotide polymorphisms (SNPs) in the promoter region of its receptor gene (growth hormone secretagogue receptor type 1a--GHSR) have also been associated with weight loss outcomes following long-term dietary intervention in adults with impaired glucose tolerance. Our objectives were to evaluate changes in serum ghrelin levels and determine the effect of GHSR promoter polymorphisms on post-RYGB surgery weight loss. METHODS Preoperative and 6-month postoperative serum ghrelin levels were measured in 37 patients with extreme obesity undergoing RYGB surgery. Total ghrelin was also measured in liver tissue collected intraoperatively. Association analysis between genotypes for SNPs rs9819506 and rs490683 in the promoter region of the GHSR gene and weight loss outcomes in the 30 months following surgery was performed in over 650 RYGB patients. RESULTS Serum ghrelin levels increased after RYGB surgery. Weight loss trajectories were significantly different using an additive model for both ghrelin SNPs, with patients homozygous for the rs490683 CC genotype exhibiting the most weight loss. Weight loss trajectories were also different using a dominant model. The rs490683 risk allele demonstrated decreased promoter activity in vitro. CONCLUSIONS The role of increased ghrelin levels in weight loss outcomes following RYGB surgery may be influenced by variation in the GHSR gene.
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Affiliation(s)
- Michelle E Matzko
- Obesity Institute, Geisinger Clinic, 100 N Academy Ave, Danville, PA 17822-2130, USA
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