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Lavoie O, Turmel A, Mattoon P, Desrosiers WJ, Plamondon J, Michael NJ, Caron A. Hypothalamic GABAergic Neurons Expressing Cellular Retinoic Acid Binding Protein 1 (CRABP1) Are Sensitive to Metabolic Status and Liraglutide in Male Mice. Neuroendocrinology 2024; 114:681-697. [PMID: 38631315 PMCID: PMC11232952 DOI: 10.1159/000538716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 03/29/2024] [Indexed: 04/19/2024]
Abstract
INTRODUCTION Owing to their privileged anatomical location, neurons of the arcuate nucleus of the hypothalamus (ARC) play critical roles in sensing and responding to metabolic signals such as leptin and glucagon-like peptide 1 (GLP-1). In addition to the well-known proopiomelanocortin (POMC)- and agouti-related peptide (AgRP)-expressing neurons, subpopulations of GABAergic neurons are emerging as key regulators of energy balance. However, the precise identity of these metabolic neurons is still elusive. Here, we identified and characterized the molecular signature of a novel population of GABAergic neurons of the ARC expressing Cellular retinoic acid binding protein 1 (Crabp1). METHODS Using a combination of immunohistochemistry and in situ hybridization techniques, we investigated the expression of Crabp1 across the mouse brain and characterized the molecular identity of Crabp1ARC neurons. We also determined whether Crabp1ARC neurons are sensitive to fasting, leptin, and GLP1R agonism by assessing cFOS immunoreactivity as a marker of neuronal activity. RESULTS Crabp1ARC neurons represent a novel GABAergic neuronal population robustly enriched in the ARC and are distinct from the prototypical melanocortin neurons. Crabp1ARC neurons overlap with three subpopulations of yet uncharacterized ARC neurons expressing Htr3b, Tbx19, and Tmem215. Notably, Crabp1ARC neurons express receptors for metabolic hormones and their activity is modulated by the nutritional state and GLP1R agonism. CONCLUSION Crabp1ARC neurons represent a novel heterogeneous population of GABAergic neurons sensitive to metabolic status.
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Affiliation(s)
- Olivier Lavoie
- Faculty of Pharmacy, Université Laval, Quebec City, Québec, Canada
- Quebec Heart and Lung Institute, Quebec City, Québec, Canada
| | - Audrey Turmel
- Faculty of Pharmacy, Université Laval, Quebec City, Québec, Canada
- Quebec Heart and Lung Institute, Quebec City, Québec, Canada
| | - Paige Mattoon
- Quebec Heart and Lung Institute, Quebec City, Québec, Canada
| | | | - Julie Plamondon
- Quebec Heart and Lung Institute, Quebec City, Québec, Canada
| | - Natalie Jane Michael
- Faculty of Pharmacy, Université Laval, Quebec City, Québec, Canada
- Quebec Heart and Lung Institute, Quebec City, Québec, Canada
| | - Alexandre Caron
- Faculty of Pharmacy, Université Laval, Quebec City, Québec, Canada
- Quebec Heart and Lung Institute, Quebec City, Québec, Canada
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Ng GYQ, Sheng DPLK, Bae HG, Kang SW, Fann DYW, Park J, Kim J, Alli-Shaik A, Lee J, Kim E, Park S, Han JW, Karamyan V, Okun E, Dheen T, Hande MP, Vemuganti R, Mallilankaraman K, Lim LHK, Kennedy BK, Drummond GR, Sobey CG, Gunaratne J, Mattson MP, Foo RSY, Jo DG, Arumugam TV. Integrative epigenomic and transcriptomic analyses reveal metabolic switching by intermittent fasting in brain. GeroScience 2022; 44:2171-2194. [PMID: 35357643 DOI: 10.1007/s11357-022-00537-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 02/21/2022] [Indexed: 11/04/2022] Open
Abstract
Intermittent fasting (IF) remains the most effective intervention to achieve robust anti-aging effects and attenuation of age-related diseases in various species. Epigenetic modifications mediate the biological effects of several environmental factors on gene expression; however, no information is available on the effects of IF on the epigenome. Here, we first found that IF for 3 months caused modulation of H3K9 trimethylation (H3K9me3) in the cerebellum, which in turn orchestrated a plethora of transcriptomic changes involved in robust metabolic switching processes commonly observed during IF. Second, a portion of both the epigenomic and transcriptomic modulations induced by IF was remarkably preserved for at least 3 months post-IF refeeding, indicating that memory of IF-induced epigenetic changes was maintained. Notably, though, we found that termination of IF resulted in a loss of H3K9me3 regulation of the transcriptome. Collectively, our study characterizes the novel effects of IF on the epigenetic-transcriptomic axis, which controls myriad metabolic processes. The comprehensive analyses undertaken in this study reveal a molecular framework for understanding how IF impacts the metabolo-epigenetic axis of the brain and will serve as a valuable resource for future research.
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Affiliation(s)
- Gavin Yong-Quan Ng
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | | | - Han-Gyu Bae
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - Sung Wook Kang
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - David Yang-Wei Fann
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jinsu Park
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - Joonki Kim
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Natural Products Research Center, Korea Institute of Science and Technology, Gangneung, Gangwon-do, Republic of Korea
| | - Asfa Alli-Shaik
- Translational Biomedical Proteomics Group, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, Singapore
| | - Jeongmi Lee
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - Eunae Kim
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - Sunyoung Park
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - Jeung-Whan Han
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - Vardan Karamyan
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Science Center, Amarillo, TX, USA
| | - Eitan Okun
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-IIan University, Ramat Gan, Israel
| | - Thameem Dheen
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Manoor Prakash Hande
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Raghu Vemuganti
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Karthik Mallilankaraman
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Lina H K Lim
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Brian K Kennedy
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School Medicine, National University of Singapore, Singapore, Singapore.,Buck Institute for Research On Aging, Novato, USA
| | - Grant R Drummond
- Centre for Cardiovascular Biology and Disease Research, Department of Microbiology, Anatomy, Physiology and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC, Australia
| | - Christopher G Sobey
- Centre for Cardiovascular Biology and Disease Research, Department of Microbiology, Anatomy, Physiology and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC, Australia
| | - Jayantha Gunaratne
- Translational Biomedical Proteomics Group, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, Singapore.,Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Mark P Mattson
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Roger Sik-Yin Foo
- Genome Institute of Singapore, Singapore, Singapore. .,Centre for Translational Medicine, Cardiovascular Research Institute, National University Health Systems, National University of Singapore, Singapore, Singapore.
| | - Dong-Gyu Jo
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea.
| | - Thiruma V Arumugam
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. .,School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea. .,Centre for Cardiovascular Biology and Disease Research, Department of Microbiology, Anatomy, Physiology and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC, Australia.
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Cen HH, Hussein B, Botezelli JD, Wang S, Zhang JA, Noursadeghi N, Jessen N, Rodrigues B, Timmons JA, Johnson JD. Human and mouse muscle transcriptomic analyses identify insulin receptor mRNA downregulation in hyperinsulinemia-associated insulin resistance. FASEB J 2022; 36:e22088. [PMID: 34921686 PMCID: PMC9255858 DOI: 10.1096/fj.202100497rr] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 11/18/2021] [Accepted: 11/23/2021] [Indexed: 01/03/2023]
Abstract
Hyperinsulinemia is commonly viewed as a compensatory response to insulin resistance, yet studies have demonstrated that chronically elevated insulin may also drive insulin resistance. The molecular mechanisms underpinning this potentially cyclic process remain poorly defined, especially on a transcriptome-wide level. Transcriptomic meta-analysis in >450 human samples demonstrated that fasting insulin reliably and negatively correlated with INSR mRNA in skeletal muscle. To establish causality and study the direct effects of prolonged exposure to excess insulin in muscle cells, we incubated C2C12 myotubes with elevated insulin for 16 h, followed by 6 h of serum starvation, and established that acute AKT and ERK signaling were attenuated in this model of in vitro hyperinsulinemia. Global RNA-sequencing of cells both before and after nutrient withdrawal highlighted genes in the insulin receptor (INSR) signaling, FOXO signaling, and glucose metabolism pathways indicative of 'hyperinsulinemia' and 'starvation' programs. Consistently, we observed that hyperinsulinemia led to a substantial reduction in Insr gene expression, and subsequently a reduced surface INSR and total INSR protein, both in vitro and in vivo. Bioinformatic modeling combined with RNAi identified SIN3A as a negative regulator of Insr mRNA (and JUND, MAX, and MXI as positive regulators of Irs2 mRNA). Together, our analysis identifies mechanisms which may explain the cyclic processes underlying hyperinsulinemia-induced insulin resistance in muscle, a process directly relevant to the etiology and disease progression of type 2 diabetes.
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Affiliation(s)
- Haoning Howard Cen
- Department of Cellular and Physiological Sciences, Life Science Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Bahira Hussein
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - José Diego Botezelli
- Department of Cellular and Physiological Sciences, Life Science Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Su Wang
- Department of Cellular and Physiological Sciences, Life Science Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jiashuo Aaron Zhang
- Department of Cellular and Physiological Sciences, Life Science Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nilou Noursadeghi
- Department of Cellular and Physiological Sciences, Life Science Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Niels Jessen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.,Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
| | - Brian Rodrigues
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - James A Timmons
- Augur Precision Medicine LTD, Stirling University Innovation Park, Stirling, Scotland.,William Harvey Research Institute, Queen Mary University of London, London, UK
| | - James D Johnson
- Department of Cellular and Physiological Sciences, Life Science Institute, University of British Columbia, Vancouver, British Columbia, Canada
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Sellers J, Brooks A, Fernando S, Westenberger G, Junkins S, Smith S, Min K, Lawan A. Fasting-Induced Upregulation of MKP-1 Modulates the Hepatic Response to Feeding. Nutrients 2021; 13:nu13113941. [PMID: 34836195 PMCID: PMC8619756 DOI: 10.3390/nu13113941] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 10/27/2021] [Accepted: 11/02/2021] [Indexed: 12/14/2022] Open
Abstract
The liver plays a key role in whole-body, glucose and lipid homeostasis. Nutritional signals in response to fasting and refeeding regulate hepatic lipid synthesis. It is established that activation of mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1) in response to overnutrition regulates MAPK-dependent pathways that control lipid metabolism in the liver. However, the regulatory mechanisms and the impact of the actions of MKP-1 in hepatic response to fasting remains unclear. We investigated the effect of fasting on the expression of MKP-1 and the impact on hepatic response to feeding. In this study, we demonstrate that fasting stress induced upregulation of hepatic MKP-1 protein levels with a corresponding downregulation of p38 MAPK and JNK phosphorylation in mouse livers. We found that MKP-1-deficient livers are resistant to fasting-induced hepatic steatosis. Hepatic MKP-1 deficiency impaired fasting-induced changes in the levels of key transcription factors involved in the regulation of fatty acid and cholesterol metabolism including Srebf2 and Srebf1c. Mechanistically, MKP-1 negatively regulates Srebf2 expression by attenuating p38 MAPK pathway, suggesting its contribution to the metabolic effects of MKP-1 deficiency in the fasting liver. These findings support the hypothesis that upregulation of MKP-1 is a physiological relevant response and might be beneficial in hepatic lipid utilization during fasting in the liver. Collectively, these data unravel some of the complexity and tissue specific interaction of MKP-1 action in response to changes in nutritional cues, including fasting and excess nutrients
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Affiliation(s)
- Jacob Sellers
- Department of Biological Sciences, University of Alabama in Huntsville, Huntsville, AL 35899, USA; (J.S.); (A.B.); (S.F.); (G.W.); (S.J.); (S.S.)
| | - Abigail Brooks
- Department of Biological Sciences, University of Alabama in Huntsville, Huntsville, AL 35899, USA; (J.S.); (A.B.); (S.F.); (G.W.); (S.J.); (S.S.)
| | - Savanie Fernando
- Department of Biological Sciences, University of Alabama in Huntsville, Huntsville, AL 35899, USA; (J.S.); (A.B.); (S.F.); (G.W.); (S.J.); (S.S.)
| | - Gabrielle Westenberger
- Department of Biological Sciences, University of Alabama in Huntsville, Huntsville, AL 35899, USA; (J.S.); (A.B.); (S.F.); (G.W.); (S.J.); (S.S.)
| | - Sadie Junkins
- Department of Biological Sciences, University of Alabama in Huntsville, Huntsville, AL 35899, USA; (J.S.); (A.B.); (S.F.); (G.W.); (S.J.); (S.S.)
| | - Shauri Smith
- Department of Biological Sciences, University of Alabama in Huntsville, Huntsville, AL 35899, USA; (J.S.); (A.B.); (S.F.); (G.W.); (S.J.); (S.S.)
| | - Kisuk Min
- Department of Kinesiology, University of Texas at El Paso, El Paso, TX 79968, USA;
| | - Ahmed Lawan
- Department of Biological Sciences, University of Alabama in Huntsville, Huntsville, AL 35899, USA; (J.S.); (A.B.); (S.F.); (G.W.); (S.J.); (S.S.)
- Correspondence: ; Tel.: +1-256-824-6264
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5
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Gonçalves GHM, Tristão SM, Volpi RE, Almeida-Pereira G, de Carvalho Borges B, Donato J, de Castro M, Antunes-Rodrigues J, Elias LLK. STAT3 but Not ERK2 Is a Crucial Mediator Against Diet-Induced Obesity via VMH Neurons. Diabetes 2021; 70:1498-1507. [PMID: 33883215 DOI: 10.2337/db20-0658] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 04/18/2021] [Indexed: 11/13/2022]
Abstract
Leptin plays an important role in the protection against diet-induced obesity (DIO) by its actions in ventromedial hypothalamic (VMH) neurons. However, little is known about the intracellular mechanisms involved in these effects. To assess the role of the STAT3 and ERK2 signaling in neurons that express the steroidogenic factor 1 (SF1) in the VMH in energy homeostasis, we used cre-lox technology to generate male and female mice with specific disruption of STAT3 or ERK2 in SF1 neurons of the VMH. We demonstrated that the conditional knockout of STAT3 in SF1 neurons of the VMH did not affect body weight, food intake, energy expenditure, or glucose homeostasis in animals on regular chow. However, with high-fat diet (HFD) challenge, loss of STAT3 in SF1 neurons caused a significant increase in body weight, food intake, and energy efficiency that was more remarkable in females, which also showed a decrease in energy expenditure. In contrast, deletion of ERK2 in SF1 neurons of VMH did not have any impact on energy homeostasis in both regular diet and HFD conditions. In conclusion, STAT3 but not ERK2 signaling in SF1 neurons of VMH plays a crucial role in protection against DIO in a sex-specific pattern.
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Affiliation(s)
- Gabriel Henrique Marques Gonçalves
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Sabrina Mara Tristão
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Rafaella Eduarda Volpi
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Gislaine Almeida-Pereira
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Beatriz de Carvalho Borges
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | | | - Margaret de Castro
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - José Antunes-Rodrigues
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Lucila Leico Kagohara Elias
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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6
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Short-term fasting differentially regulates PI3K/AkT/mTOR and ERK signalling in the rat hypothalamus. Mech Ageing Dev 2020; 192:111358. [PMID: 32961167 DOI: 10.1016/j.mad.2020.111358] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/12/2020] [Accepted: 09/13/2020] [Indexed: 11/20/2022]
Abstract
It is known that insulin secreted by pancreatic β-cells enters the brain by crossing the blood-brain barrier. However, it was demonstrated that insulin expression occurs in various brain regions as well. Albeit the list of insulin actions in the brain is long and it includes control of energy homeostasis, neuronal survival, maintenance of synaptic plasticity and cognition, not much is known about the adaptive significance of insulin synthesis in brain. We previously reported that short-term fasting promotes insulin expression and subsequent activation of insulin receptor in the rat periventricular nucleus. In order to uncover a physiological importance of the fasting-induced insulin expression in hypothalamus, we analyzed the effect of short-term food deprivation on the expression of several participants of PI3K/AKT/mTOR and Ras/MAPK signaling pathways that are typically activated by this hormone. We found that the hypothalamic content of total and activated IRS1, IRS2, PI3K, and mTOR remained unchanged, but phosphorylated AKT1/2/3 was decreased. The levels of activated ERK1/2 were increased after six-hour fasting. Moreover, activated ERK1/2 was co-expressed with activated insulin receptor in the nucleus arcuatus. Our previously published and current findings suggest that the ERK activation in hypothalamus was at least partially initiated by the centrally produced insulin.
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Kassouf T, Sumara G. Impact of Conventional and Atypical MAPKs on the Development of Metabolic Diseases. Biomolecules 2020; 10:biom10091256. [PMID: 32872540 PMCID: PMC7563211 DOI: 10.3390/biom10091256] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 02/06/2023] Open
Abstract
The family of mitogen-activated protein kinases (MAPKs) consists of fourteen members and has been implicated in regulation of virtually all cellular processes. MAPKs are divided into two groups, conventional and atypical MAPKs. Conventional MAPKs are further classified into four sub-families: extracellular signal-regulated kinases 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK1, 2 and 3), p38 (α, β, γ, δ), and extracellular signal-regulated kinase 5 (ERK5). Four kinases, extracellular signal-regulated kinase 3, 4, and 7 (ERK3, 4 and 7) as well as Nemo-like kinase (NLK) build a group of atypical MAPKs, which are activated by different upstream mechanisms than conventional MAPKs. Early studies identified JNK1/2 and ERK1/2 as well as p38α as a central mediators of inflammation-evoked insulin resistance. These kinases have been also implicated in the development of obesity and diabetes. Recently, other members of conventional MAPKs emerged as important mediators of liver, skeletal muscle, adipose tissue, and pancreatic β-cell metabolism. Moreover, latest studies indicate that atypical members of MAPK family play a central role in the regulation of adipose tissue function. In this review, we summarize early studies on conventional MAPKs as well as recent findings implicating previously ignored members of the MAPK family. Finally, we discuss the therapeutic potential of drugs targeting specific members of the MAPK family.
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Mir BA, Mason SA, May AK, Russell AP, Foletta VC. Overexpression of NDRG2 in skeletal muscle does not ameliorate the effects of stress in vivo. Exp Physiol 2020; 105:1326-1338. [PMID: 32468595 DOI: 10.1113/ep088620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/26/2020] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Do elevated levels of the stress-response protein NDRG2 protect against fasting and chronic disease in mouse skeletal muscle? What is the main finding and its importance? NDRG2 levels increased in the tibialis anterior muscle in response to fasting and the effects of motor neurone disease. No alleviation of the stress-related and proteasomal pathways, mitochondrial dysfunction or muscle mass loss was observed even with the addition of exogenous NDRG2 indicating that the increase in NDRG2 is a normal adaptive response. ABSTRACT Skeletal muscle mass loss and dysfunction can arise from stress, which leads to enhanced protein degradation and metabolic impairment. The expression of N-myc downstream-regulated gene 2 (NDRG2) is induced in response to different stressors and is protective against the effects of stress in some tissues and cell types. Here, we investigated the endogenous NDRG2 response to the stress of fasting and chronic disease in mice and whether exogenous NDRG2 overexpression through adeno-associated viral (AAV) treatment ameliorated the response of skeletal muscle to these conditions. Endogenous levels of NDRG2 increased in the tibialis anterior muscle in response to 24 h fasting and with the development of the motor neurone disease, amyotrophic lateral sclerosis, in SOD1G93A transgenic mice. Despite AAV-induced overexpression and increased expression with fasting, NDRG2 was unable to protect against the activation of proteasomal and stress pathways in response to fasting. Furthermore, NDRG2 was unable to reduce muscle mass loss, mitochondrial dysfunction and elevated oxidative and endoplasmic reticulum stress levels in SOD1G93A mice. Conversely, elevated NDRG2 levels did not exacerbate these stress responses. Overall, increasing NDRG2 levels might not be a useful therapeutic strategy to alleviate stress-related disease pathologies in skeletal muscle.
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Affiliation(s)
- Bilal A Mir
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia.,Institute of Muscle Biology & Growth, Leibniz Institute for Farm Animal Biology, Dummerstorf, Germany
| | - Shaun A Mason
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Anthony K May
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Aaron P Russell
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Victoria C Foletta
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
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Venema W, Severi I, Perugini J, Di Mercurio E, Mainardi M, Maffei M, Cinti S, Giordano A. Ciliary Neurotrophic Factor Acts on Distinctive Hypothalamic Arcuate Neurons and Promotes Leptin Entry Into and Action on the Mouse Hypothalamus. Front Cell Neurosci 2020; 14:140. [PMID: 32528252 PMCID: PMC7253709 DOI: 10.3389/fncel.2020.00140] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 04/24/2020] [Indexed: 12/13/2022] Open
Abstract
In humans and experimental animals, the administration of ciliary neurotrophic factor (CNTF) reduces food intake and body weight. To gain further insights into the mechanism(s) underlying its satiety effect, we: (i) evaluated the CNTF-dependent activation of the Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) pathway in mouse models where neuropeptide Y (NPY) and pro-opiomelanocortin (POMC) neurons can be identified by green fluorescent protein (GFP); and (ii) assessed whether CNTF promotes leptin signaling in hypothalamic feeding centers. Immunohistochemical experiments enabled us to establish that intraperitoneal injection of mouse recombinant CNTF activated the JAK2-STAT3 pathway in a substantial proportion of arcuate nucleus (ARC) NPY neurons (18.68% ± 0.60 in 24-h fasted mice and 25.50% ± 1.17 in fed mice) but exerted a limited effect on POMC neurons (4.15% ± 0.33 in 24-h fasted mice and 2.84% ± 0.45 in fed mice). CNTF-responsive NPY neurons resided in the ventromedial ARC, facing the median eminence (ME), and were surrounded by albumin immunoreactivity, suggesting that they are located outside the blood-brain barrier (BBB). In both normally fed and high-fat diet (HFD) obese animals, CNTF activated extracellular signal-regulated kinase signaling in ME β1- and β2-tanycytes, an effect that has been linked to the promotion of leptin entry into the brain. Accordingly, compared to the animals treated with leptin, mice treated with leptin/CNTF showed: (i) a significantly greater leptin content in hypothalamic protein extracts; (ii) a significant increase in phospho-STAT3 (P-STAT3)-positive neurons in the ARC and the ventromedial hypothalamic nucleus of normally fed mice; and (iii) a significantly increased number of P-STAT3-positive neurons in the ARC and dorsomedial hypothalamic nucleus of HFD obese mice. Collectively, these data suggest that exogenously administered CNTF reduces food intake by exerting a leptin-like action on distinctive NPY ARC neurons and by promoting leptin signaling in hypothalamic feeding centers.
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Affiliation(s)
- Wiebe Venema
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica Delle Marche, Ancona, Italy
| | - Ilenia Severi
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica Delle Marche, Ancona, Italy
| | - Jessica Perugini
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica Delle Marche, Ancona, Italy
| | - Eleonora Di Mercurio
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica Delle Marche, Ancona, Italy
| | - Marco Mainardi
- Institute of Neuroscience, National Research Council, Pisa, Italy
| | | | - Saverio Cinti
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica Delle Marche, Ancona, Italy.,Center of Obesity, Università Politecnica delle Marche-United Hospitals, Ancona, Italy
| | - Antonio Giordano
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica Delle Marche, Ancona, Italy
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Podyma B, Johnson DA, Sipe L, Remcho TP, Battin K, Liu Y, Yoon SO, Deppmann CD, Güler AD. The p75 neurotrophin receptor in AgRP neurons is necessary for homeostatic feeding and food anticipation. eLife 2020; 9:e52623. [PMID: 31995032 PMCID: PMC7056271 DOI: 10.7554/elife.52623] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 01/27/2020] [Indexed: 12/31/2022] Open
Abstract
Networks of neurons control feeding and activity patterns by integrating internal metabolic signals of energy balance with external environmental cues such as time-of-day. Proper circadian alignment of feeding behavior is necessary to prevent metabolic disease, and thus it is imperative that molecular players that maintain neuronal coordination of energy homeostasis are identified. Here, we demonstrate that mice lacking the p75 neurotrophin receptor, p75NTR, decrease their feeding and food anticipatory behavior (FAA) in response to daytime, but not nighttime, restricted feeding. These effects lead to increased weight loss, but do not require p75NTR during development. Instead, p75NTR is required for fasting-induced activation of neurons within the arcuate hypothalamus. Indeed, p75NTR specifically in AgRP neurons is required for FAA in response to daytime restricted feeding. These findings establish p75NTR as a novel regulator gating behavioral response to food scarcity and time-of-day dependence of circadian food anticipation.
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Affiliation(s)
- Brandon Podyma
- Department of BiologyUniversity of VirginiaCharlottesvilleUnited States
| | - Dove-Anna Johnson
- Department of BiologyUniversity of VirginiaCharlottesvilleUnited States
| | - Laura Sipe
- Department of BiologyUniversity of VirginiaCharlottesvilleUnited States
| | | | - Katherine Battin
- Department of BiologyUniversity of VirginiaCharlottesvilleUnited States
| | - Yuxi Liu
- Department of Biological Chemistry and PharmacologyThe Ohio State University College of MedicineColumbusUnited States
| | - Sung Ok Yoon
- Department of Biological Chemistry and PharmacologyThe Ohio State University College of MedicineColumbusUnited States
| | | | - Ali Deniz Güler
- Department of BiologyUniversity of VirginiaCharlottesvilleUnited States
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11
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Cabral A, Fernandez G, Tolosa MJ, Rey Moggia Á, Calfa G, De Francesco PN, Perello M. Fasting induces remodeling of the orexigenic projections from the arcuate nucleus to the hypothalamic paraventricular nucleus, in a growth hormone secretagogue receptor-dependent manner. Mol Metab 2019; 32:69-84. [PMID: 32029231 PMCID: PMC7005150 DOI: 10.1016/j.molmet.2019.11.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/14/2019] [Accepted: 11/20/2019] [Indexed: 02/06/2023] Open
Abstract
Objective Arcuate nucleus (ARC) neurons producing Agouti-related peptide (AgRP) and neuropeptide Y (NPY; ARCAgRP/NPY neurons) are activated under energy-deficit states. ARCAgRP/NPY neurons innervate the hypothalamic paraventricular nucleus (PVH), and ARC→PVH projections are recognized as key regulators of food intake. Plasma ghrelin levels increase under energy-deficit states and activate ARCAgRP/NPY neurons by acting on the growth hormone secretagogue receptor (GHSR). Here, we hypothesized that activation of ARCAgRP/NPY neurons in fasted mice would promote morphological remodeling of the ARCAgRP/NPY→PVH projections in a GHSR-dependent manner. Methods We performed 1) fluorescent immunohistochemistry, 2) imaging of green fluorescent protein (GFP) signal in NPY-GFP mice, and 3) DiI axonal labeling in brains of ad libitum fed or fasted mice with pharmacological or genetic blockage of the GHSR signaling and then estimated the density and strength of ARCAgRP/NPY→PVH fibers by assessing the mean fluorescence intensity, the absolute area with fluorescent signal, and the intensity of the fluorescent signal in the fluorescent area of the PVH. Results We found that 1) the density and strength of ARCAgRP/NPY fibers increase in the PVH of fasted mice, 2) the morphological remodeling of the ARCAgRP/NPY→PVH projections correlates with the activation of PVH neurons, and 3) PVH neurons are not activated in ARC-ablated mice. We also found that fasting-induced remodeling of ARCAgRP/NPY→PVH fibers and PVH activation are impaired in mice with pharmacological or genetic blockage of GHSR signaling. Conclusion This evidence shows that the connectivity between hypothalamic circuits controlling food intake can be remodeled in the adult brain, depending on the energy balance conditions, and that GHSR activity is a key regulator of this phenomenon. The density and strength of ARCAgRP/NPY→PVH fibers increase in fasted mice. Remodeling of ARCAgRP/NPY→PVH projections correlates with the activation of PVH neurons. GHSR signaling is required for fasting-induced ARCAgRP/NPY→PVH projection remodeling.
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Affiliation(s)
- Agustina Cabral
- Laboratorio de Neurofisiología, Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional La Plata y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina
| | - Gimena Fernandez
- Laboratorio de Neurofisiología, Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional La Plata y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina
| | - María J Tolosa
- Laboratorio de Neurofisiología, Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional La Plata y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina
| | - Ángeles Rey Moggia
- Laboratorio de Neurofisiología, Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional La Plata y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina
| | - Gastón Calfa
- Instituto de Farmacología Experimental de Córdoba (IFEC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Pablo N De Francesco
- Laboratorio de Neurofisiología, Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional La Plata y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina
| | - Mario Perello
- Laboratorio de Neurofisiología, Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional La Plata y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina.
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12
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Horie T, Park G, Inaba Y, Hashiuchi E, Iezaki T, Tokumura K, Fukasawa K, Yamada T, Hiraiwa M, Kitaguchi Y, Kamada H, Kaneda K, Tanaka T, Inoue H, Hinoi E. MAPK Erk5 in Leptin Receptor‒Expressing Neurons Controls Body Weight and Systemic Energy Homeostasis in Female Mice. Endocrinology 2019; 160:2837-2848. [PMID: 31555819 DOI: 10.1210/en.2019-00090] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 09/11/2019] [Indexed: 01/06/2023]
Abstract
Extracellular signal-regulated kinase 5 (Erk5), a member of the MAPK family, is specifically phosphorylated and activated by MAPK/Erk kinase-5. Although it has been implicated in odor discrimination and long-term memory via its expression in the central nervous system, little is known regarding the physiological importance of neuronal Erk5 in body weight and energy homeostasis. In the current study, systemic insulin injection significantly induced phosphorylation of Erk5 in the hypothalamus. Moreover, Erk5 deficiency in leptin receptor (LepR)‒expressing neurons led to an obesity phenotype, with increased white adipose tissue mass due to increased adipocyte size, only in female mice fed a normal chow diet. Furthermore, Erk5 deficiency in LepR-expressing neurons showed impaired glucose tolerance along with decreased physical activity, food intake, and energy expenditure. These results suggest that Erk5 controls body weight and systemic energy homeostasis probably via its expression in hypothalamic neurons in female mice, thereby providing a target for metabolic diseases such as obesity and type 2 diabetes mellitus.
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Affiliation(s)
- Tetsuhiro Horie
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan
- Laboratory of Pharmacology, Department of Bioactive Molecules, Gifu Pharmaceutical University, Gifu, Japan
| | - Gyujin Park
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan
- Laboratory of Pharmacology, Department of Bioactive Molecules, Gifu Pharmaceutical University, Gifu, Japan
| | - Yuka Inaba
- Metabolism and Nutrition Research Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Emi Hashiuchi
- Department of Physiology and Metabolism, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Takashi Iezaki
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan
- Venture Business Laboratory, Organization of Frontier Science and Innovation, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Kazuya Tokumura
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan
| | - Kazuya Fukasawa
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan
- Laboratory of Pharmacology, Department of Bioactive Molecules, Gifu Pharmaceutical University, Gifu, Japan
| | - Takanori Yamada
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan
- Laboratory of Pharmacology, Department of Bioactive Molecules, Gifu Pharmaceutical University, Gifu, Japan
| | - Manami Hiraiwa
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan
- Laboratory of Pharmacology, Department of Bioactive Molecules, Gifu Pharmaceutical University, Gifu, Japan
| | - Yuka Kitaguchi
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan
- Laboratory of Pharmacology, Department of Bioactive Molecules, Gifu Pharmaceutical University, Gifu, Japan
| | - Hikari Kamada
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan
| | - Katsuyuki Kaneda
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan
| | - Tomohiro Tanaka
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Hiroshi Inoue
- Metabolism and Nutrition Research Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Ishikawa, Japan
- Department of Physiology and Metabolism, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Eiichi Hinoi
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa, Japan
- Laboratory of Pharmacology, Department of Bioactive Molecules, Gifu Pharmaceutical University, Gifu, Japan
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13
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Wang D, Xu B, Wang J, Wang H, Guo J, Ji H, Li S, Wu R, Yang H, Lian S. Response of the maternal hypothalamus to cold stress during late pregnancy in rats. Brain Res 2019; 1722:146354. [PMID: 31356783 DOI: 10.1016/j.brainres.2019.146354] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 07/24/2019] [Accepted: 07/25/2019] [Indexed: 12/11/2022]
Abstract
Maternal stress is a key risk factor in the development of offspring. We previously identified prenatal cold stress-induced anxiety-like behavior reduced in the offspring of rats along with negative feedback regulation from the maternal hippocampus on the hypothalamic-pituitary-adrenal (HPA) axis during prenatal cold stress. However, the precise function of the maternal hypothalamus response to cold stress during late pregnancy in rats has not yet been determined. Therefore, we examined proteins in the hypothalamus that respond to aldosterone, neurodevelopment, inflammation and apoptosis. Our results show that prenatal cold stress induced the expression of mineralocorticoid receptors (MR) and 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), suggesting prenatal cold stress may promote the elevation of aldosterone levels in the hypothalamus. Remarkably, increased expression of brain derived neurotrophic factor (BDNF) helped to replenish intracellular peptidergic stores and ensure homeostatic balance during prenatal cold stress. Furthermore, prenatal cold stress reduced the expression of c-Fos via STAT3 and ERK1/2 pathways in the hypothalamus. Moreover, prenatal cold stress induced NF-κB phosphorylation at Ser536, then promoted the expression of inducible nitric oxide synthase (iNOS) and induced an apoptosis-related protein response. Together, this study confirms that changes in the maternal hypothalamus during cold stress in late pregnancy are directly reflective of the response of the HPA to cold stress and demonstrates how the hypothalamus coordinates cold stress. We suggest mechanisms which might explain how these states might be linked with an abnormal stress response.
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Affiliation(s)
- Di Wang
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China
| | - Bin Xu
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China
| | - Jianfa Wang
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China
| | - Hai Wang
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China
| | - Jingru Guo
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China
| | - Hong Ji
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China
| | - Shize Li
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China
| | - Rui Wu
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China
| | - Huanmin Yang
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China.
| | - Shuai Lian
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China.
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14
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Laing BT, Li P, Schmidt CA, Bunner W, Yuan Y, Landry T, Prete A, McClung JM, Huang H. AgRP/NPY Neuron Excitability Is Modulated by Metabotropic Glutamate Receptor 1 During Fasting. Front Cell Neurosci 2018; 12:276. [PMID: 30233321 PMCID: PMC6129575 DOI: 10.3389/fncel.2018.00276] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 08/08/2018] [Indexed: 12/17/2022] Open
Abstract
The potential to control feeding behavior via hypothalamic AgRP/NPY neurons has led to many approaches to modulate their excitability—particularly by glutamatergic input. In the present study using NPY-hrGFP reporter mice, we visualize AgRP/NPY neuronal metabotropic glutamate receptor 1 (mGluR1) expression and test the effect of fasting on mGluR1 function. Using the pharmacological agonist dihydroxyphenylglycine (DHPG), we demonstrate the enhanced capacity of mGluR1 to drive firing of AgRP/NPY neurons after overnight fasting, while antagonist 3-MATIDA reduces firing. Further, under synaptic blockade we demonstrate that DHPG acts directly on AgRP/NPY neurons to create a slow inward current. Using an in vitro approach, we show that emulation of intracellular signals associated with fasting by forskolin enhances DHPG induced phosphorylation of extracellularly regulated-signal kinase (1/2) in GT1-7 cell culture. We show in vivo that blocking mGluR1 by antagonist 3-MATIDA lowers fasting induced refeeding. In summary, this study identifies a novel layer of regulation on AgRP/NPY neurons integrated with whole body energy balance.
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Affiliation(s)
- Brenton T Laing
- Human Performance Laboratory, Department of Kinesiology, East Carolina University, Greenville, NC, United States.,East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States
| | - Peixin Li
- Human Performance Laboratory, Department of Kinesiology, East Carolina University, Greenville, NC, United States.,East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States
| | - Cameron A Schmidt
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States.,Department of Physiology, East Carolina University, Greenville, NC, United States
| | - Wyatt Bunner
- Human Performance Laboratory, Department of Kinesiology, East Carolina University, Greenville, NC, United States.,East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States
| | - Yuan Yuan
- Human Performance Laboratory, Department of Kinesiology, East Carolina University, Greenville, NC, United States.,East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States
| | - Taylor Landry
- Human Performance Laboratory, Department of Kinesiology, East Carolina University, Greenville, NC, United States.,East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States
| | - Amber Prete
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States
| | - Joseph M McClung
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States.,Department of Physiology, East Carolina University, Greenville, NC, United States
| | - Hu Huang
- Human Performance Laboratory, Department of Kinesiology, East Carolina University, Greenville, NC, United States.,East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States.,Department of Physiology, East Carolina University, Greenville, NC, United States
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15
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Craig SL, Gault VA, Irwin N. Emerging therapeutic potential for xenin and related peptides in obesity and diabetes. Diabetes Metab Res Rev 2018; 34:e3006. [PMID: 29633491 DOI: 10.1002/dmrr.3006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 03/21/2018] [Accepted: 03/25/2018] [Indexed: 12/16/2022]
Abstract
Xenin-25 is a 25-amino acid peptide hormone co-secreted from the same enteroendocrine K-cell as the incretin peptide glucose-dependent insulinotropic polypeptide. There is no known specific receptor for xenin-25, but studies suggest that at least some biological actions may be mediated through interaction with the neurotensin receptor. Original investigation into the physiological significance of xenin-25 focussed on effects related to gastrointestinal transit and satiety. However, xenin-25 has been demonstrated in pancreatic islets and recently shown to possess actions in relation to the regulation of insulin and glucagon secretion, as well as promoting beta-cell survival. Accordingly, the beneficial impact of xenin-25, and related analogues, has been assessed in animal models of diabetes-obesity. In addition, studies have demonstrated that metabolically active fragment peptides of xenin-25, particularly xenin-8, possess independent therapeutic promise for diabetes, as well as serving as bioactive components for the generation of multi-acting hybrid peptides with antidiabetic potential. This review focuses on continuing developments with xenin compounds in relation to new therapeutic approaches for diabetes-obesity.
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Affiliation(s)
- Sarah L Craig
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Victor A Gault
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
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16
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Jang SP, Park SH, Jung JS, Lee HJ, Hong JW, Lee JY, Suh HW. Characterization of changes of pain behavior and signal transduction system in food-deprived mice. Anim Cells Syst (Seoul) 2018; 22:227-233. [PMID: 30460102 PMCID: PMC6138332 DOI: 10.1080/19768354.2018.1490348] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 05/23/2018] [Accepted: 05/28/2018] [Indexed: 12/18/2022] Open
Abstract
Fasting in general causes several metabolic changes. In the present study, we examined the possible changes of several types of nociception during the food deprivation were investigated in mice. After the mice were forced into the fasting for 12, 24, or 48 h, the changes of nociception were measured by the tail-flick, writhing, formalin or von-frey tests. We found that the nociceptive behavior induced by intraperitoneally (i.p.) administered acetic acid (writhing response) or intraplantar injection of 5% formalin into the hind-paw were reduced in fasted group. In addition, the tail-flick response and threshold for nociception in mechanical von-frey test were also elevated in fasted group. Moreover, the p-CREB and p-ERK levels in the dorsal root ganglia (DRG) and the spinal cord were reduced in food-deprived group. Furthermore, p-AMPKα1 expressions in DRG and the spinal cord were up-regulated, whereas p-mTOR in DRG and the spinal cord was down-regulated in food-deprived group. Our results suggest that the chemical, mechanical, and thermal nociceptions appear to be reduced in a food-deprived mouse group. Additionally, reduction of nociception in food-deprived group appears to be closely associated with the expressions of several signal transduction molecules such as ERK, CREB, AMPKα1 and mTOR proteins in DRG and the spinal cord.
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Affiliation(s)
- Sang-Pil Jang
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon, Korea
| | - Seong-Hwan Park
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon, Korea
| | - Jun-Sub Jung
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon, Korea
| | - Hee-Jung Lee
- Department of Life science, Hallym University, Chuncheon, Korea
| | - Jung-Woo Hong
- Department of Biomedical Science, Hallym University, Chuncheon, Korea
| | - Jae-Yong Lee
- Department of Biochemistry, College of Medicine, Hallym University, Chuncheon, Korea
| | - Hong-Won Suh
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon, Korea
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17
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Fujimura M, Usuki F. Methylmercury induces oxidative stress and subsequent neural hyperactivity leading to cell death through the p38 MAPK-CREB pathway in differentiated SH-SY5Y cells. Neurotoxicology 2018; 67:226-233. [PMID: 29913201 DOI: 10.1016/j.neuro.2018.06.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 05/13/2018] [Accepted: 06/13/2018] [Indexed: 12/20/2022]
Abstract
Methylmercury (MeHg) induces site-specific cerebrocortical neuronal cell death. In our previous study using an in vivo mouse model, we reported that MeHg-induced cerebrocortical neuronal cell death may be due to neural hyperactivity triggered by activation of kinase pathways. However, the detailed molecular mechanism remained to be completely understood. In this study, we analyzed detailed signaling pathways for MeHg-induced neuronal cell death using all-trans-retinoic acid (RA) differentiated SH-SY5Y cells, which show neuron-like morphological changes and express neuron/synapse markers for cerebrocortical neurons. Time course studies revealed that MeHg-induced upregulation of c-fos, a marker of neural activation, preceded neuronal cell death. These results were similar to those observed in a MeHg-intoxicated mouse model. We observed early expression of the oxidative stress marker thymidine glycol followed by activation of p44/42 mitogen-activated protein kinase (MAPK) and p38 MAPK, and an increase in cAMP response element binding protein (CREB). Investigation of the effects of specific kinase inhibitors revealed that SB203580, a specific inhibitor for p38 MAPK, significantly blocked the upregulation of c-fos and the subsequent neuronal cell death. In contrast, PD98059 and U0126, specific inhibitors for p44/p42 MAPK, showed no effects on MeHg-induced neurotoxicity. Furthermore, the antioxidants Trolox and edaravone significantly suppressed MeHg-induced thymidine glycol expression, p38 MAPK-CREB pathway activation, and neurotoxicity. Altogether, these results suggest that MeHg-induced oxidative stress and subsequent activation of the p38 MAPK-CREB pathway contribute to cerebrocortical neuronal hyperactivity and subsequent neuronal cell death.
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Affiliation(s)
- Masatake Fujimura
- Department of Basic Medical Sciences, National Institute for Minamata Disease, Kumamoto, Japan.
| | - Fusako Usuki
- Department of Clinical Medicine, National Institute for Minamata Disease, Kumamoto, Japan
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18
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Yu CH, Hsieh YS, Chen PN, Chen JR, Kuo DY. Knockdown of the transcript of ERK in the brain modulates hypothalamic neuropeptide-mediated appetite control in amphetamine-treated rats. Br J Pharmacol 2018; 175:726-739. [PMID: 29215157 DOI: 10.1111/bph.14120] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 11/03/2017] [Accepted: 11/17/2017] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Amphetamine is a releaser of dopamine stored in synaptic terminals, which can suppress appetite by changing the expression levels of neuropeptide Y (NPY) and proopiomelanocortin (POMC) in the hypothalamus. This study explored whether ERKs are involved in appetite control mediated by cAMP response element binding protein (CREB), NPY and POMC in amphetamine-treated rats. EXPERIMENTAL APPROACH Rats were given amphetamine for 4 days, and changes in feeding behaviour and expression levels of phosphorylated-ERK (pERK), pCREB, NPY and melanocortin MC3 receptors were examined and compared. KEY RESULTS Following amphetamine treatment, food intake, body weight and NPY expression decreased, whereas the expression of pERK, pCREB, MC3 receptors and pCREB/DNA binding activity increased. In amphetamine-treated rats, both cerebral ERK knockdown and pretreatment with a peripheral dopamine receptor antagonist decreased NPY but increased pERK, pCREB and MC3 receptor expression. Moreover, the immunofluorescence of hypothalamic pERK increased following amphetamine treatment. CONCLUSIONS AND IMPLICATIONS These results suggest that ERK/CREB signalling participates in the effects mediated by dopamine receptor/NPY/POMC on appetite control in rats treated with amphetamine. These findings advance the knowledge on the involvement of ERK/CREB signalling in the reciprocal regulation by NPY and POMC of appetite after amphetamine treatment.
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Affiliation(s)
- Ching-Han Yu
- Department of Physiology, Chung Shan Medical University and Chung Shan Medical University Hospital, Taichung City, Taiwan
| | - Yih-Shou Hsieh
- Institute of Biochemistry and Biotechnology, Chung Shan Medical University and Chung Shan Medical University Hospital, Taichung City, Taiwan
| | - Pei-Ni Chen
- Institute of Biochemistry and Biotechnology, Chung Shan Medical University and Chung Shan Medical University Hospital, Taichung City, Taiwan
| | - Jeng-Rung Chen
- Department of Veterinary Medicine, National Chung Hsing University, Taichung City, Taiwan, R.O.C
| | - Dong-Yih Kuo
- Department of Physiology, Chung Shan Medical University and Chung Shan Medical University Hospital, Taichung City, Taiwan
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19
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Liu L, Liu H, Fu C, Li C, Li F. Acetate induces anorexia via up-regulating the hypothalamic pro-opiomelanocortin ( POMC) gene expression in rabbits. JOURNAL OF ANIMAL AND FEED SCIENCES 2017. [DOI: 10.22358/jafs/75979/2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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20
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Suyama S, Ralevski A, Liu ZW, Dietrich MO, Yada T, Simonds SE, Cowley MA, Gao XB, Diano S, Horvath TL. Plasticity of calcium-permeable AMPA glutamate receptors in Pro-opiomelanocortin neurons. eLife 2017; 6. [PMID: 28762946 PMCID: PMC5538821 DOI: 10.7554/elife.25755] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 06/17/2017] [Indexed: 11/13/2022] Open
Abstract
POMC neurons integrate metabolic signals from the periphery. Here, we show in mice that food deprivation induces a linear current-voltage relationship of AMPAR-mediated excitatory postsynaptic currents (EPSCs) in POMC neurons. Inhibition of EPSCs by IEM-1460, an antagonist of calcium-permeable (Cp) AMPARs, diminished EPSC amplitude in the fed but not in the fasted state, suggesting entry of GluR2 subunits into the AMPA receptor complex during food deprivation. Accordingly, removal of extracellular calcium from ACSF decreased the amplitude of mEPSCs in the fed but not the fasted state. Ten days of high-fat diet exposure, which was accompanied by elevated leptin levels and increased POMC neuronal activity, resulted in increased expression of Cp-AMPARs on POMC neurons. Altogether, our results show that entry of calcium via Cp-AMPARs is inherent to activation of POMC neurons, which may underlie a vulnerability of these neurons to calcium overload while activated in a sustained manner during over-nutrition. DOI:http://dx.doi.org/10.7554/eLife.25755.001
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Affiliation(s)
- Shigetomo Suyama
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, United States.,Division of Integrative Physiology, Department of Physiology, Jichi Medical University, Tochigi, Japan
| | - Alexandra Ralevski
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, United States
| | - Zhong-Wu Liu
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, United States
| | - Marcelo O Dietrich
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, United States
| | - Toshihiko Yada
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University, Tochigi, Japan
| | - Stephanie E Simonds
- Biomedicine Discovery Institute, Department of Physiology, Monash University, Clayton, Australia
| | - Michael A Cowley
- Biomedicine Discovery Institute, Department of Physiology, Monash University, Clayton, Australia
| | - Xiao-Bing Gao
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, United States
| | - Sabrina Diano
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, United States.,Departments of Ob/Gyn and Reproductive Sciences, Yale University School of Medicine, New Haven, United States.,Department of Neurobiology, Yale University School of Medicine, New Haven, United States
| | - Tamas L Horvath
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, United States.,Departments of Ob/Gyn and Reproductive Sciences, Yale University School of Medicine, New Haven, United States.,Department of Neurobiology, Yale University School of Medicine, New Haven, United States.,Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary
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21
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Site-specific neural hyperactivity via the activation of MAPK and PKA/CREB pathways triggers neuronal degeneration in methylmercury-intoxicated mice. Toxicol Lett 2017; 271:66-73. [DOI: 10.1016/j.toxlet.2017.03.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 01/17/2017] [Accepted: 03/02/2017] [Indexed: 11/20/2022]
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22
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Akhmedov D, Rajendran K, Mendoza-Rodriguez MG, Berdeaux R. Knock-in Luciferase Reporter Mice for In Vivo Monitoring of CREB Activity. PLoS One 2016; 11:e0158274. [PMID: 27336479 PMCID: PMC4940169 DOI: 10.1371/journal.pone.0158274] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 06/13/2016] [Indexed: 11/18/2022] Open
Abstract
The cAMP response element binding protein (CREB) is induced during fasting in the liver, where it stimulates transcription of rate-limiting gluconeogenic genes to maintain metabolic homeostasis. Adenoviral and transgenic CREB reporters have been used to monitor hepatic CREB activity non-invasively using bioluminescence reporter imaging. However, adenoviral vectors and randomly inserted transgenes have several limitations. To overcome disadvantages of the currently used strategies, we created a ROSA26 knock-in CREB reporter mouse line (ROSA26-CRE-luc). cAMP-inducing ligands stimulate the reporter in primary hepatocytes and myocytes from ROSA26-CRE-luc animals. In vivo, these animals exhibit little hepatic CREB activity in the ad libitum fed state but robust induction after fasting. Strikingly, CREB was markedly stimulated in liver, but not in skeletal muscle, after overnight voluntary wheel-running exercise, uncovering differential regulation of CREB in these tissues under catabolic states. The ROSA26-CRE-luc mouse line is a useful resource to study dynamics of CREB activity longitudinally in vivo and can be used as a source of primary cells for analysis of CREB regulatory pathways ex vivo.
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Affiliation(s)
- Dmitry Akhmedov
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
| | - Kavitha Rajendran
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
| | - Maria G. Mendoza-Rodriguez
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
| | - Rebecca Berdeaux
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
- Center for Metabolic and Degenerative Diseases, Institute of Molecular Medicine, University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
- Cell and Regulatory Biology Program, The University of Texas Graduate School of Biomedical Sciences at Houston, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
- * E-mail:
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23
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Kim ER, Lew PS, Spirkina A, Mizuno TM. Xenin-induced feeding suppression is not mediated through the activation of central extracellular signal-regulated kinase signaling in mice. Behav Brain Res 2016; 312:118-26. [PMID: 27316340 DOI: 10.1016/j.bbr.2016.06.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 06/09/2016] [Accepted: 06/13/2016] [Indexed: 10/21/2022]
Abstract
Xenin is a gut hormone that reduces food intake by partly acting through the hypothalamus via neurotensin receptor 1 (Ntsr1). However, specific signaling pathways that mediate xenin-induced feeding suppression are not fully understood. Activation of Ntsr1 leads to the activation of the extracellular signal-regulated kinase (ERK). Hypothalamic ERK participates in the regulation of food intake by mediating the effect of hormonal signals. Therefore, we hypothesized that the anorectic effect of xenin is mediated by hypothalamic ERK signaling. To address this hypothesis, we compared levels of phosphorylation of ERK1/2 (pERK1/2) in the hypothalamus of both control and xenin-treated mice. The effect of xenin on ERK1/2 phosphorylation was also examined in mouse hypothalamic neuronal cell lines with or without Ntsr1. We also examined the effect of the blockade of central ERK signaling on xenin-induced feeding suppression in mice. The intraperitoneal (i.p.) injection of xenin caused a significant increase in the number of pERK1/2-immunoreactive cells in the hypothalamic arcuate nucleus. The majority of pERK1/2-positive cells expressed neuronal nuclei (NeuN), a marker for neurons. Xenin treatment increased pERK1/2 levels in one cell line expressing Ntsr1 but not another line without Ntsr1 expression. Both i.p. and intracerebroventricular (i.c.v.) injections of xenin reduced food intake in mice. The i.c.v. pre-treatment with U0126, a selective inhibitor of ERK1/2 upstream kinases, did not affect xenin-induced reduction in food intake. These findings suggest that although xenin activates ERK signaling in subpopulations of hypothalamic neurons, xenin does not require the activation of hypothalamic ERK signaling pathway to elicit feeding suppression.
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Affiliation(s)
- Eun Ran Kim
- Division of Endocrinology & Metabolic Disease, Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
| | - Pei San Lew
- Division of Endocrinology & Metabolic Disease, Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
| | - Alexandra Spirkina
- Division of Endocrinology & Metabolic Disease, Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
| | - Tooru M Mizuno
- Division of Endocrinology & Metabolic Disease, Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada.
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24
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Kwon O, Kim KW, Kim MS. Leptin signalling pathways in hypothalamic neurons. Cell Mol Life Sci 2016; 73:1457-77. [PMID: 26786898 PMCID: PMC11108307 DOI: 10.1007/s00018-016-2133-1] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/20/2015] [Accepted: 01/07/2016] [Indexed: 12/25/2022]
Abstract
Leptin is the most critical hormone in the homeostatic regulation of energy balance among those so far discovered. Leptin primarily acts on the neurons of the mediobasal part of hypothalamus to regulate food intake, thermogenesis, and the blood glucose level. In the hypothalamic neurons, leptin binding to the long form leptin receptors on the plasma membrane initiates multiple signaling cascades. The signaling pathways known to mediate the actions of leptin include JAK-STAT signaling, PI3K-Akt-FoxO1 signaling, SHP2-ERK signaling, AMPK signaling, and mTOR-S6K signaling. Recent evidence suggests that leptin signaling in hypothalamic neurons is also linked to primary cilia function. On the other hand, signaling molecules/pathways mitigating leptin actions in hypothalamic neurons have been extensively investigated in an effort to treat leptin resistance observed in obesity. These include SOCS3, tyrosine phosphatase PTP1B, and inflammatory signaling pathways such as IKK-NFκB and JNK signaling, and ER stress-mitochondrial signaling. In this review, we discuss leptin signaling pathways in the hypothalamus, with a particular focus on the most recently discovered pathways.
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Affiliation(s)
- Obin Kwon
- Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea
- Appetite Regulation Laboratory, Asan Institute for Life Science, Seoul, 05505, Korea
| | - Ki Woo Kim
- Department of Pharmacology, Yonsei University Wonju College of Medicine, Wonju, 26426, Korea
- Department of Global Medical Science, Yonsei University Wonju College of Medicine, Wonju, 26426, Korea
| | - Min-Seon Kim
- Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea.
- Appetite Regulation Laboratory, Asan Institute for Life Science, Seoul, 05505, Korea.
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25
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Jeon Y, Aja S, Ronnett GV, Kim EK. D-chiro-inositol glycan reduces food intake by regulating hypothalamic neuropeptide expression via AKT-FoxO1 pathway. Biochem Biophys Res Commun 2016; 470:818-23. [PMID: 26802467 DOI: 10.1016/j.bbrc.2016.01.115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 01/19/2016] [Indexed: 01/12/2023]
Abstract
The regulation of food intake is important for body energy homeostasis. Hypothalamic insulin signaling decreases food intake by upregulating the expression of anorexigenic neuropeptides and downregulating the expression of orexigenic neuropeptides. INS-2, a Mn(2+) chelate of 4-O-(2-amino-2-deoxy-β-D-galactopyranosyl)-3-O-methyl-D-chiro-inositol, acts as an insulin mimetic and sensitizer. We found that intracerebroventricular injection of INS-2 decreased body weight and food intake in mice. In hypothalamic neuronal cell lines, INS-2 downregulated the expression of neuropeptide Y (NPY), an orexigenic neuropeptide, but upregulated the expression of proopiomelanocortin (POMC), an anorexigenic neuropeptide, via modulation of the AKT-forkhead box-containing protein-O1 (FoxO1) pathway. Pretreatment of these cells with INS-2 enhanced the action of insulin on downstream signaling, leading to a further decrease in NPY expression and increase in POMC expression. These data indicate that INS-2 reduces food intake by regulating the expression of the hypothalamic neuropeptide genes through the AKT-FoxO1 pathway downstream of insulin.
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Affiliation(s)
- Yoonjeong Jeon
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology, Daegu, Republic of Korea
| | - Susan Aja
- Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Gabriele V Ronnett
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology, Daegu, Republic of Korea; Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Eun-Kyoung Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology, Daegu, Republic of Korea; Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science & Technology, Daegu, Republic of Korea.
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26
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Halls ML, Bathgate RAD, Sutton SW, Dschietzig TB, Summers RJ. International Union of Basic and Clinical Pharmacology. XCV. Recent advances in the understanding of the pharmacology and biological roles of relaxin family peptide receptors 1-4, the receptors for relaxin family peptides. Pharmacol Rev 2015; 67:389-440. [PMID: 25761609 DOI: 10.1124/pr.114.009472] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Relaxin, insulin-like peptide 3 (INSL3), relaxin-3, and INSL5 are the cognate ligands for the relaxin family peptide (RXFP) receptors 1-4, respectively. RXFP1 activates pleiotropic signaling pathways including the signalosome protein complex that facilitates high-sensitivity signaling; coupling to Gα(s), Gα(i), and Gα(o) proteins; interaction with glucocorticoid receptors; and the formation of hetero-oligomers with distinctive pharmacological properties. In addition to relaxin-related ligands, RXFP1 is activated by Clq-tumor necrosis factor-related protein 8 and by small-molecular-weight agonists, such as ML290 [2-isopropoxy-N-(2-(3-(trifluoromethylsulfonyl)phenylcarbamoyl)phenyl)benzamide], that act allosterically. RXFP2 activates only the Gα(s)- and Gα(o)-coupled pathways. Relaxin-3 is primarily a neuropeptide, and its cognate receptor RXFP3 is a target for the treatment of depression, anxiety, and autism. A variety of peptide agonists, antagonists, biased agonists, and an allosteric modulator target RXFP3. Both RXFP3 and the related RXFP4 couple to Gα(i)/Gα(o) proteins. INSL5 has the properties of an incretin; it is secreted from the gut and is orexigenic. The expression of RXFP4 in gut, adipose tissue, and β-islets together with compromised glucose tolerance in INSL5 or RXFP4 knockout mice suggests a metabolic role. This review focuses on the many advances in our understanding of RXFP receptors in the last 5 years, their signal transduction mechanisms, the development of novel compounds that target RXFP1-4, the challenges facing the field, and current prospects for new therapeutics.
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Affiliation(s)
- Michelle L Halls
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Ross A D Bathgate
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Steve W Sutton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Thomas B Dschietzig
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Roger J Summers
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
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27
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MacPherson REK, Baumeister P, Peppler WT, Wright DC, Little JP. Reduced cortical BACE1 content with one bout of exercise is accompanied by declines in AMPK, Akt, and MAPK signaling in obese, glucose-intolerant mice. J Appl Physiol (1985) 2015; 119:1097-104. [PMID: 26404616 DOI: 10.1152/japplphysiol.00299.2015] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 09/17/2015] [Indexed: 12/15/2022] Open
Abstract
Obesity and type 2 diabetes are significant risk factors in the development of neurodegenerative diseases, such as Alzheimer's disease. A variety of cellular mechanisms, such as altered Akt and AMPK and increased inflammatory signaling, contribute to neurodegeneration. Exercise training can improve markers of neurodegeneration, but the underlying mechanisms remain unknown. The purpose of this study was to determine the effects of a single bout of exercise on markers of neurodegeneration and inflammation in brains from mice fed a high-fat diet. Male C57BL/6 mice were fed a low (LFD; 10% kcal from lard)- or a high-fat diet (HFD; 60% kcal from lard) for 7 wk. HFD mice underwent an acute bout of exercise (treadmill running: 15 m/min, 5% incline, 120 min) followed by a recovery period of 2 h. The HFD increased body mass and glucose intolerance (both P < 0.05). This was accompanied by an approximately twofold increase in the phosphorylation of Akt, ERK, and GSK in the cortex (P < 0.05). Following exercise, there was a decrease in beta-site amyloid precursor protein cleaving enzyme 1 (BACE1; P < 0.05) and activity (P < 0.001). This was accompanied by a reduction in AMPK phosphorylation, indicative of a decline in cellular stress (P < 0.05). Akt and ERK phosphorylation were decreased following exercise in HFD mice to a level similar to that of the LFD mice (P < 0.05). This study demonstrates that a single bout of exercise can reduce BACE1 content and activity independent of changes in adiposity. This effect is associated with reductions in Akt, ERK, and AMPK signaling in the cortex.
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Affiliation(s)
- R E K MacPherson
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada; and
| | - P Baumeister
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | | | - D C Wright
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada; and
| | - J P Little
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
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28
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Kocan M, Ang SY, Summers RJ. Orthosteric, Allosteric and Biased Signalling at the Relaxin-3 Receptor RXFP3. Neurochem Res 2015; 41:610-9. [PMID: 26294284 DOI: 10.1007/s11064-015-1701-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 08/12/2015] [Accepted: 08/13/2015] [Indexed: 11/29/2022]
Abstract
Relaxin-3 is a neuropeptide that has roles in stress, memory and appetite regulation. The peptide acts on its cognate receptor RXFP3 to induce coupling to inhibitory G proteins to inhibit adenylyl cyclase and activate MAP-kinases such as ERK1/2, p38MAPK and JNK. Other relaxin family peptides can activate the receptor to produce alternative patterns of signalling and there is an allosteric modulator 135PAM1 that displays probe-selectivity. There are now a variety of selective peptide agonists and antagonists that will assist in the determination of the physiological roles of the relaxin-RXFP3 system and its potential as a drug target.
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Affiliation(s)
- Martina Kocan
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, Melbourne, VIC, 3052, Australia
| | - Sheng Yu Ang
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, Melbourne, VIC, 3052, Australia
| | - Roger J Summers
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, Melbourne, VIC, 3052, Australia.
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29
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Evidence suggesting phosphodiesterase-3B regulation of NPY/AgRP gene expression in mHypoE-46 hypothalamic neurons. Neurosci Lett 2015; 604:113-8. [PMID: 26254161 DOI: 10.1016/j.neulet.2015.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 07/21/2015] [Accepted: 08/03/2015] [Indexed: 01/03/2023]
Abstract
Hypothalamic neurons expressing neuropeptide Y (NPY) and agouti related-protein (AgRP) are critical regulators of feeding behavior and body weight, and transduce the action of many peripheral signals including leptin and insulin. However, intracellular signaling molecules involved in regulating NPY/AgRP neuronal activity are incompletely understood. Since phosphodiesterase-3B (PDE3B) mediates the hypothalamic action of leptin and insulin on feeding, and is expressed in NPY/AgRP neurons, PDE3B could play a significant role in regulating NPY/AgRP neuronal activity. To investigate the direct regulation of NPY/AgRP neuronal activity by PDE3B, we examined the effects of gain-of-function or reduced function of PDE3B on NPY/AgRP gene expression in a clonal hypothalamic neuronal cell line, mHypoE-46, which endogenously express NPY, AgRP and PDE3B. Overexpression of PDE3B in mHypoE-46 cells with transfection of pcDNA-3.1-PDE3B expression plasmid significantly decreased NPY and AgRP mRNA levels and p-CREB levels as compared to the control plasmid. For the PDE3B knockdown study, mHypoE-46 cells transfected with lentiviral PDE3BshRNAmir plasmid or non-silencing lentiviral shRNAmir control plasmid were selected with puromycin, and stably transfected cells were grown in culture for 48h. Results showed that PDE3BshRNAmir mediated knockdown of PDE3B mRNA and protein levels (∼60-70%) caused an increase in both NPY and AgRP gene expression and in p-CREB levels. Together, these results demonstrate a reciprocal change in NPY and AgRP gene expression following overexpression and knockdown of PDE3B, and suggest a significant role for PDE3B in the regulation of NPY/AgRP gene expression in mHypoE-46 hypothalamic neurons.
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30
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Zhang J, Zhou Y, Chen C, Yu F, Wang Y, Gu J, Ma L, Ho G. ERK1/2 mediates glucose-regulated POMC gene expression in hypothalamic neurons. J Mol Endocrinol 2015; 54:125-35. [PMID: 25624461 DOI: 10.1530/jme-14-0330] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Hypothalamic glucose-sensing neurons regulate the expression of genes encoding feeding-related neuropetides POMC, AgRP, and NPY - the key components governing metabolic homeostasis. AMP-activated protein kinase (AMPK) is postulated to be the molecular mediator relaying glucose signals to regulate the expression of these neuropeptides. Whether other signaling mediator(s) plays a role is not clear. In this study, we investigated the role of ERK1/2 using primary hypothalamic neurons as the model system. The primary neurons were differentiated from hypothalamic progenitor cells. The differentiated neurons possessed the characteristic neuronal cell morphology and expressed neuronal post-mitotic markers as well as leptin-regulated orexigenic POMC and anorexigenic AgRP/NPY genes. Treatment of cells with glucose dose-dependently increased POMC and decreased AgRP/NPY expression with a concurrent suppression of AMPK phosphorylation. In addition, glucose treatment dose-dependently increased the ERK1/2 phosphorylation. Blockade of ERK1/2 activity with its specific inhibitor PD98059 partially (approximately 50%) abolished glucose-induced POMC expression, but had little effect on AgRP/NPY expression. Conversely, blockade of AMPK activity with its specific inhibitor produced a partial (approximately 50%) reversion of low-glucose-suppressed POMC expression, but almost completely blunted the low-glucose-induced AgRP/NPY expression. The results indicate that ERK1/2 mediated POMC but not AgRP/NPY expression. Confirming the in vitro findings, i.c.v. administration of PD98059 in rats similarly attenuated glucose-induced POMC expression in the hypothalamus, but again had little effect on AgRP/NPY expression. The results are indicative of a novel role of ERK1/2 in glucose-regulated POMC expression and offer new mechanistic insights into hypothalamic glucose sensing.
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Affiliation(s)
- Juan Zhang
- Department of PediatricsThe Second Affiliated Hospital of Shantou University Medical College, Shantou 515041, ChinaDepartment of Molecular PathologyShantou University Medical College, Shantou 515041, China
| | - Yunting Zhou
- Department of PediatricsThe Second Affiliated Hospital of Shantou University Medical College, Shantou 515041, ChinaDepartment of Molecular PathologyShantou University Medical College, Shantou 515041, China
| | - Cheng Chen
- Department of PediatricsThe Second Affiliated Hospital of Shantou University Medical College, Shantou 515041, ChinaDepartment of Molecular PathologyShantou University Medical College, Shantou 515041, China
| | - Feiyuan Yu
- Department of PediatricsThe Second Affiliated Hospital of Shantou University Medical College, Shantou 515041, ChinaDepartment of Molecular PathologyShantou University Medical College, Shantou 515041, China
| | - Yun Wang
- Department of PediatricsThe Second Affiliated Hospital of Shantou University Medical College, Shantou 515041, ChinaDepartment of Molecular PathologyShantou University Medical College, Shantou 515041, China
| | - Jiang Gu
- Department of PediatricsThe Second Affiliated Hospital of Shantou University Medical College, Shantou 515041, ChinaDepartment of Molecular PathologyShantou University Medical College, Shantou 515041, China
| | - Lian Ma
- Department of PediatricsThe Second Affiliated Hospital of Shantou University Medical College, Shantou 515041, ChinaDepartment of Molecular PathologyShantou University Medical College, Shantou 515041, China
| | - Guyu Ho
- Department of PediatricsThe Second Affiliated Hospital of Shantou University Medical College, Shantou 515041, ChinaDepartment of Molecular PathologyShantou University Medical College, Shantou 515041, China
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Grosbellet E, Gourmelen S, Pévet P, Criscuolo F, Challet E. Leptin normalizes photic synchronization in male ob/ob mice, via indirect effects on the suprachiasmatic nucleus. Endocrinology 2015; 156:1080-90. [PMID: 25521581 DOI: 10.1210/en.2014-1570] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mounting evidence indicates a strong link between metabolic diseases and circadian dysfunctions. The metabolic hormone leptin, substantially increased in dietary obesity, displays chronobiotic properties. Here we investigated whether leptin is involved in the alteration of timing associated with obesity, via direct or indirect effects on the suprachiasmatic nucleus (SCN), the site of the master clock. Photic synchronization was studied in obese ob/ob mice (deficient in leptin), either injected or not with high doses of recombinant murine leptin (5 mg/kg). This was performed first at a behavioral level, by shifting the light-dark cycle and inducing phase shifts by 30-minute light pulses and then at molecular levels (c-FOS and P-ERK1/2). Moreover, to characterize the targets mediating the chronomodulatory effects of leptin, we studied the induction of phosphorylated signal transducer and activator of transcription 3 (P-STAT3) in the SCN and in different structures projecting to the SCN, including the medial hypothalamus. Ob/ob mice showed altered photic synchronization, including augmented light-induced phase delays. Acute leptin treatment normalized the photic responses of the SCN at both the behavioral and molecular levels (decrease of light-induced c-FOS). Leptin-induced P-STAT3 was modulated by light in the arcuate nucleus and both the ventromedial and dorsomedial hypothalamic nuclei, whereas its expression was independent of the presence of leptin in the SCN. These results suggest an indirect action of leptin on the SCN, possibly mediated by the medial hypothalamus. Taken together, these results highlight a central role of leptin in the relationship between metabolic disturbances and circadian disruptions.
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Affiliation(s)
- Edith Grosbellet
- Regulation of Circadian Clocks Team (E.G., S.G., P.P., E.C.), Institute of Cellular and Integrative Neurosciences, Centre National de la Recherche Scientifique UPR3212, and Evolutionary Ecophysiology Team (E.G., F.C.), Department of Ecology, Physiology, and Ethology, Hubert Curien Pluridisciplinary Institute, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7178, University of Strasbourg, 67000 Strasbourg, France
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Liang Q, Zhong L, Zhang J, Wang Y, Bornstein SR, Triggle CR, Ding H, Lam KSL, Xu A. FGF21 maintains glucose homeostasis by mediating the cross talk between liver and brain during prolonged fasting. Diabetes 2014; 63:4064-75. [PMID: 25024372 DOI: 10.2337/db14-0541] [Citation(s) in RCA: 198] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Hepatic gluconeogenesis is a main source of blood glucose during prolonged fasting and is orchestrated by endocrine and neural pathways. Here we show that the hepatocyte-secreted hormone fibroblast growth factor 21 (FGF21) induces fasting gluconeogenesis via the brain-liver axis. Prolonged fasting induces activation of the transcription factor peroxisome proliferator-activated receptor α (PPARα) in the liver and subsequent hepatic production of FGF21, which enters into the brain to activate the hypothalamic-pituitary-adrenal (HPA) axis for release of corticosterone, thereby stimulating hepatic gluconeogenesis. Fasted FGF21 knockout (KO) mice exhibit severe hypoglycemia and defective hepatic gluconeogenesis due to impaired activation of the HPA axis and blunted release of corticosterone, a phenotype similar to that observed in PPARα KO mice. By contrast, intracerebroventricular injection of FGF21 reverses fasting hypoglycemia and impairment in hepatic gluconeogenesis by restoring corticosterone production in both FGF21 KO and PPARα KO mice, whereas all these central effects of FGF21 were abrogated by blockage of hypothalamic FGF receptor-1. FGF21 acts directly on the hypothalamic neurons to activate the mitogen-activated protein kinase extracellular signal-related kinase 1/2 (ERK1/2), thereby stimulating the expression of corticotropin-releasing hormone by activation of the transcription factor cAMP response element binding protein. Therefore, FGF21 maintains glucose homeostasis during prolonged fasting by fine tuning the interorgan cross talk between liver and brain.
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Affiliation(s)
- Qingning Liang
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, China Department of Medicine, The University of Hong Kong, Hong Kong, China
| | - Ling Zhong
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, China Department of Medicine, The University of Hong Kong, Hong Kong, China
| | - Jialiang Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, China Department of Medicine, The University of Hong Kong, Hong Kong, China
| | - Yu Wang
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, China Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, China
| | | | - Chris R Triggle
- Department of Pharmacology, Weill Cornell Medical College in Qatar, Doha, Qatar
| | - Hong Ding
- Department of Pharmacology, Weill Cornell Medical College in Qatar, Doha, Qatar
| | - Karen S L Lam
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, China Department of Medicine, The University of Hong Kong, Hong Kong, China
| | - Aimin Xu
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, China Department of Medicine, The University of Hong Kong, Hong Kong, China Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, China
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Davis KE, Carstens EJ, Irani BG, Gent LM, Hahner LM, Clegg DJ. Sexually dimorphic role of G protein-coupled estrogen receptor (GPER) in modulating energy homeostasis. Horm Behav 2014; 66:196-207. [PMID: 24560890 PMCID: PMC4051842 DOI: 10.1016/j.yhbeh.2014.02.004] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 02/07/2014] [Accepted: 02/08/2014] [Indexed: 12/30/2022]
Abstract
This article is part of a Special Issue "Energy Balance". The classical estrogen receptors, estrogen receptor-α and estrogen receptor-β are well established in the regulation of body weight and energy homeostasis in both male and female mice, whereas, the role for G protein-coupled estrogen receptor 1 (GPER) as a modulator of energy homeostasis remains controversial. This study sought to determine whether gene deletion of GPER (GPER KO) alters body weight, body adiposity, food intake, and energy homeostasis in both males and females. Male mice lacking GPER developed moderate obesity and larger adipocyte size beginning at 8 weeks of age, with significant reductions in energy expenditure, but not food intake or adipocyte number. Female GPER KO mice developed increased body weight relative to WT females a full 6 weeks later than the male GPER KO mice. Female GPER KO mice also had reductions in energy expenditure, but no significant increases in body fat content. Consistent with their decrease in energy expenditure, GPER KO males and females showed significant reductions in two brown fat thermogenic proteins. GPER KO females, prior to their divergence in body weight, were less sensitive than WT females to the feeding-inhibitory effects of leptin and CCK. Additionally, body weight was not as modulated by ovariectomy or estradiol replacement in GPER KO mice. Estradiol treatment activated phosphorylated extracellular signal-regulated kinase (pERK) in WT but not GPER KO females. For the first time, GPER expression was found in the adipocyte but not the stromal fraction of adipose tissue. Together, these results provide new information elucidating a sexual dimorphism in GPER function in the development of postpubertal energy balance.
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Affiliation(s)
- Kathryn E Davis
- University of Texas Southwestern Medical Center, Department of Plastic Surgery, 5323 Harry Hines Blvd., Dallas, TX 75390-8860, USA
| | - Elizabeth J Carstens
- University of Texas Southwestern Medical Center, School of Medicine, 5323 Harry Hines Blvd., Dallas, TX 75390-8854, USA
| | - Boman G Irani
- University of Texas Southwestern Medical Center, Department of Internal Medicine, 5323 Harry Hines Blvd., Dallas, TX 75390-8854, USA
| | - Lana M Gent
- University of Texas Southwestern Medical Center, Department of Internal Medicine, 5323 Harry Hines Blvd., Dallas, TX 75390-8854, USA
| | - Lisa M Hahner
- University of Texas Southwestern Medical Center, Department of Internal Medicine, 5323 Harry Hines Blvd., Dallas, TX 75390-8854, USA
| | - Deborah J Clegg
- University of Texas Southwestern Medical Center, Department of Internal Medicine, 5323 Harry Hines Blvd., Dallas, TX 75390-8854, USA.
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Khan AM, Walker EM, Dominguez N, Watts AG. Neural input is critical for arcuate hypothalamic neurons to mount intracellular signaling responses to systemic insulin and deoxyglucose challenges in male rats: implications for communication within feeding and metabolic control networks. Endocrinology 2014; 155:405-16. [PMID: 24265445 PMCID: PMC3891932 DOI: 10.1210/en.2013-1480] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The hypothalamic arcuate nucleus (ARH) controls rat feeding behavior in part through peptidergic neurons projecting to the hypothalamic paraventricular nucleus (PVH). Hindbrain catecholaminergic (CA) neurons innervate both the PVH and ARH, and ablation of CA afferents to PVH neuroendocrine neurons prevents them from mounting cellular responses to systemic metabolic challenges such as insulin or 2-deoxy-d-glucose (2-DG). Here, we asked whether ablating CA afferents also limits their ARH responses to the same challenges or alters ARH connectivity with the PVH. We examined ARH neurons for three features: (1) CA afferents, visualized by dopamine-β-hydroxylase (DBH)- immunoreactivity; (2) activation by systemic metabolic challenge, as measured by increased numbers of neurons immunoreactive (ir) for phosphorylated ERK1/2 (pERK1/2); and (3) density of PVH-targeted axons immunoreactive for the feeding control peptides Agouti-related peptide and α-melanocyte-stimulating hormone (αMSH). Loss of PVH DBH immunoreactivity resulted in concomitant ARH reductions of DBH-ir and pERK1/2-ir neurons in the medial ARH, where AgRP neurons are enriched. In contrast, pERK1/2 immunoreactivity after systemic metabolic challenge was absent in αMSH-ir ARH neurons. Yet surprisingly, axonal αMSH immunoreactivity in the PVH was markedly increased in CA-ablated animals. These results indicate that (1) intrinsic ARH activity is insufficient to recruit pERK1/2-ir ARH neurons during systemic metabolic challenges (rather, hindbrain-originating CA neurons are required); and (2) rats may compensate for a loss of CA innervation to the ARH and PVH by increased expression of αMSH. These findings highlight the existence of a hierarchical dependence for ARH responses to neural and humoral signals that influence feeding behavior and metabolism.
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Affiliation(s)
- Arshad M Khan
- UTEP Systems Neuroscience Laboratory (A.M.K., E.M.W., N.D.), Border Biomedical Research Center (A.M.K., E.M.W.), Department of Biological Sciences (A.M.K., E.M.W., N.D.), and Graduate Program in Pathobiology (E.M.W.), University of Texas at El Paso, El Paso, Texas 79968; and Department of Biological Sciences (A.M.K., A.G.W.), University of Southern California, Los Angeles, Los Angeles, California 90089
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Fusco S, Pani G. Brain response to calorie restriction. Cell Mol Life Sci 2013; 70:3157-70. [PMID: 23269433 PMCID: PMC11114019 DOI: 10.1007/s00018-012-1223-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 11/09/2012] [Accepted: 11/26/2012] [Indexed: 01/04/2023]
Abstract
Calorie restriction extends longevity and delays ageing in model organisms and mammals, opposing the onset and progression of an array of age-related diseases. These beneficial effects also extend to the maintenance of brain cognitive functions at later age and to the prevention, at least in rodents, of brain senescence and associated neurodegenerative disorders. In recent years, the molecular mechanisms underlying brain response to calorie restriction have begun to be elucidated, revealing the unanticipated role of a number of key nutrient sensors and nutrient-triggered signaling cascades in the translation of metabolic cues into cellular and molecular events that ultimately lead to increased cell resistance to stress, enhanced synaptic plasticity, and improved cognitive performance. Of note, the brain's role in CR also includes the activation of nutrient-sensitive hypothalamic circuitries and the implementation of neuroendocrine responses that impact the entire organism. The present review addresses emerging molecular themes in brain response to dietary restriction, and the implications of this knowledge for the understanding and the prevention of brain disorders associated with ageing and metabolic disease.
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Affiliation(s)
- Salvatore Fusco
- Institute of General Pathology, Laboratory of Cell Signaling, Catholic University Medical School, Largo F. Vito 1, Basic Science Building, room 405, Rome, Italy
| | - Giovambattista Pani
- Institute of General Pathology, Laboratory of Cell Signaling, Catholic University Medical School, Largo F. Vito 1, Basic Science Building, room 405, Rome, Italy
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Environment, leptin sensitivity, and hypothalamic plasticity. Neural Plast 2013; 2013:438072. [PMID: 23970977 PMCID: PMC3732608 DOI: 10.1155/2013/438072] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 06/25/2013] [Indexed: 12/20/2022] Open
Abstract
Regulation of feeding behavior has been a crucial step in the interplay between leptin and the arcuate nucleus of the hypothalamus (ARC). On one hand, the basic mechanisms regulating central and peripheral action of leptin are becoming increasingly clear. On the other hand, knowledge on how brain sensitivity to leptin can be modulated is only beginning to accumulate. This point is of paramount importance if one considers that pathologically obese subjects have high levels of plasmatic leptin. A possible strategy for exploring neural plasticity in the ARC is to act on environmental stimuli. This can be achieved with various protocols, namely, physical exercise, high-fat diet, caloric restriction, and environmental enrichment. Use of these protocols can, in turn, be exploited to isolate key molecules with translational potential. In the present review, we summarize present knowledge about the mechanisms of plasticity induced by the environment in the ARC. In addition, we also address the role of leptin in extrahypothalamic plasticity, in order to propose an integrated view of how a single diffusible factor can regulate diverse brain functions.
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Osaki LH, Gama P. MAPKs and signal transduction in the control of gastrointestinal epithelial cell proliferation and differentiation. Int J Mol Sci 2013; 14:10143-61. [PMID: 23670595 PMCID: PMC3676833 DOI: 10.3390/ijms140510143] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 04/19/2013] [Accepted: 04/22/2013] [Indexed: 02/06/2023] Open
Abstract
Mitogen-activated protein kinase (MAPK) pathways are activated by several stimuli and transduce the signal inside cells, generating diverse responses including cell proliferation, differentiation, migration and apoptosis. Each MAPK cascade comprises a series of molecules, and regulation takes place at different levels. They communicate with each other and with additional pathways, creating a signaling network that is important for cell fate determination. In this review, we focus on ERK, JNK, p38 and ERK5, the major MAPKs, and their interactions with PI3K-Akt, TGFβ/Smad and Wnt/β-catenin pathways. More importantly, we describe how MAPKs regulate cell proliferation and differentiation in the rapidly renewing epithelia that lines the gastrointestinal tract and, finally, we highlight the recent findings on nutritional aspects that affect MAPK transduction cascades.
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Affiliation(s)
- Luciana H Osaki
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, SP 05508-000, Brazil.
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Bathgate RAD, Halls ML, van der Westhuizen ET, Callander GE, Kocan M, Summers RJ. Relaxin family peptides and their receptors. Physiol Rev 2013; 93:405-80. [PMID: 23303914 DOI: 10.1152/physrev.00001.2012] [Citation(s) in RCA: 372] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
There are seven relaxin family peptides that are all structurally related to insulin. Relaxin has many roles in female and male reproduction, as a neuropeptide in the central nervous system, as a vasodilator and cardiac stimulant in the cardiovascular system, and as an antifibrotic agent. Insulin-like peptide-3 (INSL3) has clearly defined specialist roles in male and female reproduction, relaxin-3 is primarily a neuropeptide involved in stress and metabolic control, and INSL5 is widely distributed particularly in the gastrointestinal tract. Although they are structurally related to insulin, the relaxin family peptides produce their physiological effects by activating a group of four G protein-coupled receptors (GPCRs), relaxin family peptide receptors 1-4 (RXFP1-4). Relaxin and INSL3 are the cognate ligands for RXFP1 and RXFP2, respectively, that are leucine-rich repeat containing GPCRs. RXFP1 activates a wide spectrum of signaling pathways to generate second messengers that include cAMP and nitric oxide, whereas RXFP2 activates a subset of these pathways. Relaxin-3 and INSL5 are the cognate ligands for RXFP3 and RXFP4 that are closely related to small peptide receptors that when activated inhibit cAMP production and activate MAP kinases. Although there are still many unanswered questions regarding the mode of action of relaxin family peptides, it is clear that they have important physiological roles that could be exploited for therapeutic benefit.
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Affiliation(s)
- R A D Bathgate
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences & Department of Pharmacology, Monash University, Victoria, Australia
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Yu J, Deng R, Zhu HH, Zhang SS, Zhu C, Montminy M, Davis R, Feng GS. Modulation of fatty acid synthase degradation by concerted action of p38 MAP kinase, E3 ligase COP1, and SH2-tyrosine phosphatase Shp2. J Biol Chem 2012; 288:3823-30. [PMID: 23269672 DOI: 10.1074/jbc.m112.397885] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Src-homology 2 (SH2) domain-containing tyrosine phosphatase Shp2 has been known to regulate various signaling pathways triggered by receptor and cytoplasmic tyrosine kinases. Here we describe a novel function of Shp2 in control of lipid metabolism by mediating degradation of fatty acid synthase (FASN). p38-phosphorylated COP1 accumulates in the cytoplasm and subsequently binds FASN through Shp2 here as an adapter, leading to FASN-Shp2-COP1 complex formation and FASN degradation mediated by ubiquitination pathway. By fasting p38 is activated and stimulates FASN protein degradation in mice. Consistently, the FASN protein levels are dramatically elevated in mouse liver and pancreas in which Shp2/Ptpn11 is selectively deleted. Thus, this study identifies a new activity for Shp2 in lipid metabolism.
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Affiliation(s)
- Jianxiu Yu
- Department of Biochemistry and Molecular Cell Biology & Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine (SJTU-SM), Shanghai 200025, China.
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Seasonal leptin resistance is associated with impaired signalling via JAK2-STAT3 but not ERK, possibly mediated by reduced hypothalamic GRB2 protein. J Comp Physiol B 2011; 182:553-67. [DOI: 10.1007/s00360-011-0637-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 11/25/2011] [Accepted: 11/27/2011] [Indexed: 10/14/2022]
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Yi CX, la Fleur SE, Fliers E, Kalsbeek A. The role of the autonomic nervous liver innervation in the control of energy metabolism. Biochim Biophys Acta Mol Basis Dis 2010; 1802:416-31. [PMID: 20060897 DOI: 10.1016/j.bbadis.2010.01.006] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 12/04/2009] [Accepted: 01/05/2010] [Indexed: 01/13/2023]
Abstract
Despite a longstanding research interest ever since the early work by Claude Bernard, the functional significance of autonomic liver innervation, either sympathetic or parasympathetic, is still ill defined. This scarcity of information not only holds for the brain control of hepatic metabolism, but also for the metabolic sensing function of the liver and the way in which this metabolic information from the liver affects the brain. Clinical information from the bedside suggests that successful human liver transplantation (implying a complete autonomic liver denervation) causes no life threatening metabolic derangements, at least in the absence of severe metabolic challenges such as hypoglycemia. However, from the benchside, data are accumulating that interference with the neuronal brain-liver connection does cause pronounced changes in liver metabolism. This review provides an extensive overview on how metabolic information is sensed by the liver, and how this information is processed via neuronal pathways to the brain. With this information the brain controls liver metabolism and that of other organs and tissues. We will pay special attention to the hypothalamic pathways involved in these liver-brain-liver circuits. At this stage, we still do not know the final destination and processing of the metabolic information that is transferred from the liver to the brain. On the other hand, in recent years, there has been a considerable increase in the understanding which brain areas are involved in the control of liver metabolism via its autonomic innervation. However, in view of the ever rising prevalence of type 2 diabetes, this potentially highly relevant knowledge is still by far too limited. Thus the autonomic innervation of the liver and its role in the control of metabolism needs our continued and devoted attention.
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Affiliation(s)
- Chun-Xia Yi
- Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
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Thermoregulation in the cold changes depending on the time of day and feeding condition: physiological and anatomical analyses of involved circadian mechanisms. Neuroscience 2009; 164:1377-86. [DOI: 10.1016/j.neuroscience.2009.08.040] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 08/17/2009] [Accepted: 08/18/2009] [Indexed: 11/19/2022]
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Nguyen TVV, Yao M, Pike CJ. Dihydrotestosterone activates CREB signaling in cultured hippocampal neurons. Brain Res 2009; 1298:1-12. [PMID: 19729001 DOI: 10.1016/j.brainres.2009.08.066] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Revised: 08/20/2009] [Accepted: 08/24/2009] [Indexed: 12/17/2022]
Abstract
Although androgens induce numerous actions in brain, relatively little is known about which cell signaling pathways androgens activate in neurons. Recent work in our laboratory showed that the androgens testosterone and dihydrotestosterone (DHT) activate androgen receptor (AR)-dependent mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling. Since the transcription factor cyclic AMP response element binding protein (CREB) is a downstream effector of MAPK/ERK and androgens activate CREB in non-neuronal cells, we investigated whether androgens activate CREB signaling in neurons. First, we observed that DHT rapidly activates CREB in cultured hippocampal neurons, as evidenced by CREB phosphorylation. Further, we observed that DHT-induced CREB phosphorylation is AR-dependent, as it occurs in PC12 cells stably transfected with AR but in neither wild-type nor empty vector-transfected cells. Next, we sought to identify the signal transduction pathways upstream of CREB phosphorylation using pharmacological inhibitors. DHT-induced CREB phosphorylation in neurons was found to be dependent upon protein kinase C (PKC) signaling but independent of MAPK/ERK, phosphatidylinositol 3-kinase, protein kinase A, and Ca(2+)/calmodulin-dependent protein kinase IV. These results demonstrate that DHT induces PKC-dependent CREB signaling, which may contribute to androgen-mediated neural functions.
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Affiliation(s)
- Thuy-Vi V Nguyen
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90089, USA
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Estrada NM, Isokawa M. Metabolic Demand Stimulates CREB Signaling in the Limbic Cortex: Implication for the Induction of Hippocampal Synaptic Plasticity by Intrinsic Stimulus for Survival. Front Syst Neurosci 2009; 3:5. [PMID: 19543539 PMCID: PMC2697005 DOI: 10.3389/neuro.06.005.2009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Accepted: 05/21/2009] [Indexed: 11/13/2022] Open
Abstract
Caloric restriction by fasting has been implicated to facilitate synaptic plasticity and promote contextual learning. However, cellular and molecular mechanisms underlying the effect of fasting on memory consolidation are not completely understood. We hypothesized that fasting-induced enhancement of synaptic plasticity was mediated by the increased signaling mediated by CREB (cAMP response element binding protein), an important nuclear protein and the transcription factor that is involved in the consolidation of memories in the hippocampus. In the in vivo rat model of 18 h fasting, the expression of phosphorylated CREB (pCREB) was examined using anti-phospho-CREB (Ser133) in cardially-perfused and cryo-sectioned rat brain specimens. When compared with control animals, the hippocampus exhibited up to a twofold of increase in pCREB expression in fasted animals. The piriform cortex, the entorhinal cortex, and the cortico-amygdala transitional zone also significantly increased immunoreactivities to pCREB. In contrast, the amygdala did not show any change in the magnitude of pCREB expression in response to fasting. The arcuate nucleus in the medial hypothalamus, which was previously reported to up-regulate CREB phosphorylation during fasting of up to 48 h, was also strongly immunoreactive and provided a positive control in the present study. Our findings demonstrate a metabolic demand not only stimulates cAMP-dependent signaling cascades in the hypothalamus, but also signals to various limbic brain regions including the hippocampus by activating the CREB signaling mechanism. The hippocampus is a primary brain structure for learning and memory. It receives hypothalamic and arcuate projections directly from the fornix. The hippocampus is also situated centrally for functional interactions with other limbic cortexes by establishing reciprocal synaptic connections. We suggest that hippocampal neurons and those in the surrounding limbic cortexes are intimately involved in the metabolism-dependent plasticity, which may be essential and necessary for successful achievement of adaptive appetitive behavior.
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Affiliation(s)
- Nelly M Estrada
- Department of Biological Sciences, The University of Texas at Brownsville Brownsville, TX, USA
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Rahmouni K, Sigmund CD, Haynes WG, Mark AL. Hypothalamic ERK mediates the anorectic and thermogenic sympathetic effects of leptin. Diabetes 2009; 58:536-42. [PMID: 19066310 PMCID: PMC2646051 DOI: 10.2337/db08-0822] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Leptin is an adipocyte hormone that plays a major role in energy balance. Leptin receptors in the hypothalamus are known to signal via distinct mechanisms, including signal transducer and activator of transcription-3 (STAT3) and phosphoinositol-3 kinase (PI 3-kinase). Here, we tested the hypothesis that extracellular signal-regulated kinase (ERK) is mediating leptin action in the hypothalamus. RESEARCH DESIGN AND METHODS Biochemical, pharmacological, and physiological approaches were combined to characterize leptin activation of ERK in the hypothalamus in rats. RESULTS Leptin activates ERK1/2 in a receptor-mediated manner that involves JAK2. Leptin-induced ERK1/2 activation was restricted to the hypothalamic arcuate nucleus. Pharmacological blockade of hypothalamic ERK1/2 reverses the anorectic and weight-reducing effects of leptin. The pharmacological antagonists of ERK1/2 did not attenuate leptin-induced activation of STAT3 or PI 3-kinase. Blockade of ERK1/2 abolishes leptin-induced increases in sympathetic nerve traffic to thermogenic brown adipose tissue (BAT) but does not alter the stimulatory effects of leptin on sympathetic nerve activity to kidney, hindlimb, or adrenal gland. In contrast, blockade of PI 3-kinase prevents leptin-induced sympathetic activation to kidney but not to BAT, hindlimb, or adrenal gland. CONCLUSIONS Our findings indicate that hypothalamic ERK plays a key role in the control of food intake, body weight, and thermogenic sympathetic outflow by leptin but does not participate in the cardiovascular and renal sympathetic actions of leptin.
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Affiliation(s)
- Kamal Rahmouni
- Center on Functional Genomics of Hypertension, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA.
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Stengel A, Goebel M, Million M, Stenzel-Poore MP, Kobelt P, Mönnikes H, Taché Y, Wang L. Corticotropin-releasing factor-overexpressing mice exhibit reduced neuronal activation in the arcuate nucleus and food intake in response to fasting. Endocrinology 2009; 150:153-60. [PMID: 18787020 PMCID: PMC2630908 DOI: 10.1210/en.2008-0723] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Corticotropin-releasing factor (CRF) overexpressing (OE) mice are a genetic model that exhibits features of chronic stress. We investigated whether the adaptive feeding response to a hypocaloric challenge induced by food deprivation is impaired under conditions of chronic CRF overproduction. Food intake response to a 16-h overnight fast and ip injection of gut hormones regulating food intake were compared in CRF-OE and wild type (WT) littermate mice along with brain Fos expression, circulating ghrelin levels, and gastric emptying of a nonnutrient meal. CRF-OE mice injected ip with saline showed a 47 and 44% reduction of 30-min and 4-h cumulative food intake response to an overnight fast, respectively, compared with WT. However, the 30-min food intake decrease induced by ip cholecystokinin (3 microg/kg) and increase by ghrelin (300 microg/kg) were similar in CRF-OE and WT mice. Overnight fasting increased the plasma total ghrelin to similar levels in CRF-OE and WT mice, although CRF-OE mice had a 2-fold reduction of nonfasting ghrelin levels. The number of Fos-immunoreactive cells induced by fasting in the arcuate nucleus was reduced by 5.9-fold in CRF-OE compared with WT mice whereas no significant changes were observed in other hypothalamic nuclei. In contrast, fasted CRF-OE mice displayed a 5.6-fold increase in Fos-immunoreactive cell number in the dorsal motor nucleus of the vagus nerve and a 34% increase in 20-min gastric emptying. These findings indicate that sustained overproduction of hypothalamic CRF in mice interferes with fasting-induced activation of arcuate nucleus neurons and the related hyperphagic response.
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Affiliation(s)
- Andreas Stengel
- Center for Ulcer Research and Education, Digestive Diseases Research Center, Digestive Diseases Division, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90073, USA
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Kageyama K, Hanada K, Takayasu S, Iwasaki Y, Sakihara S, Nigawara T, Suda T. Involvement of regulatory elements on corticotropin-releasing factor gene promoter in hypothalamic 4B cells. J Endocrinol Invest 2008; 31:1079-85. [PMID: 19246974 DOI: 10.1007/bf03345656] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Corticotropin-releasing factor (CRF) plays a central role in controlling the hypothalamic-pituitary-adrenal (HPA) axis during stressful periods. CRF is synthesized and secreted in the hypothalamic paraventricular nucleus (PVN) in response to stress, and stimulates ACTH in the pituitary corticotrophs. ACTH stimulates the release of glucocorticoids from the adrenal glands, and glucocorticoids sequentially inhibit hypothalamic PVN production of CRF and pituitary production of ACTH. The effects of glucocorticoids on CRF gene regulation, however, are possibly tissue-specific since glucocorticoids stimulate CRF gene expression in the placenta and the bed nucleus of the stria terminalis, while they inhibit it in the hypothalamus. METHODS AND RESULTS In a hypothalamic cell line, 4B, we found that forskolin-stimulated CRF gene transcription was mediated by a functional cAMP-response element (CRE), which included -220 to -233 bp on the CRF 5'-promoter region. Protein kinase A, protein kinase C, and p38 mitogen-activated protein kinase pathways contributed to forskolin-induced transcriptional activity of CRF in hypothalamic 4B cells. Glucocorticoid-dependent repression of cAMP-stimulated transcriptional activity of CRF was localized to promoter sequences between -278 and -233 bp, which included a glucocorticoid regulatory element and a serum response element. CONCLUSION Taken together, these findings indicate that the regulatory elements, including CRE, negative glucocorticoid regulatory element, and a serum response element on the promoter, contribute to the regulation of CRF gene transcription in hypothalamic 4B cells.
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Affiliation(s)
- K Kageyama
- Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan.
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van der Westhuizen ET, Halls ML, Samuel CS, Bathgate RA, Unemori EN, Sutton SW, Summers RJ. Relaxin family peptide receptors – from orphans to therapeutic targets. Drug Discov Today 2008; 13:640-51. [DOI: 10.1016/j.drudis.2008.04.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 03/04/2008] [Accepted: 04/04/2008] [Indexed: 01/11/2023]
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Pike CJ, Nguyen TVV, Ramsden M, Yao M, Murphy MP, Rosario ER. Androgen cell signaling pathways involved in neuroprotective actions. Horm Behav 2008; 53:693-705. [PMID: 18222446 PMCID: PMC2424283 DOI: 10.1016/j.yhbeh.2007.11.006] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 10/31/2007] [Accepted: 11/05/2007] [Indexed: 11/15/2022]
Abstract
As a normal consequence of aging in men, testosterone levels significantly decline in both serum and brain. Age-related testosterone depletion results in increased risk of dysfunction and disease in androgen-responsive tissues, including brain. Recent evidence indicates that one deleterious effect of age-related testosterone loss in men is increased risk for Alzheimer's disease (AD). We discuss recent findings from our laboratory and others that identify androgen actions implicated in protecting the brain against neurodegenerative diseases and begin to define androgen cell signaling pathways that underlie these protective effects. Specifically, we focus on the roles of androgens as (1) endogenous negative regulators of beta-amyloid accumulation, a key event in AD pathogenesis, and (2) neuroprotective factors that utilize rapid non-genomic signaling to inhibit neuronal apoptosis. Continued elucidation of cell signaling pathways that contribute to protective actions of androgens should facilitate the development of targeted therapeutic strategies to combat AD and other age-related neurodegenerative diseases.
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Affiliation(s)
- Christian J Pike
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA.
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