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Pena-Leon V, Perez-Lois R, Villalon M, Prida E, Muñoz-Moreno D, Fernø J, Quiñones M, Al-Massadi O, Seoane LM. Novel mechanisms involved in leptin sensitization in obesity. Biochem Pharmacol 2024; 223:116129. [PMID: 38490517 DOI: 10.1016/j.bcp.2024.116129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/21/2024] [Accepted: 03/12/2024] [Indexed: 03/17/2024]
Abstract
Leptin is a hormone that is secreted by adipocytes in proportion to adipose tissue size, and that informs the brain about the energy status of the body. Leptin acts through its receptor LepRb, expressed mainly in the hypothalamus, and induces a negative energy balance by potent inhibition of feeding and activation of energy expenditure. These actions have led to huge expectations for the development of therapeutic targets for metabolic complications based on leptin-derived compounds. However, the majority of patients with obesity presents elevated leptin production, suggesting that in this setting leptin is ineffective in the regulation of energy balance. This resistance to the action of leptin in obesity has led to the development of "leptin sensitizers," which have been tested in preclinical studies. Much research has focused on generating combined treatments that act on multiple levels of the gastrointestinal-brain axis. The gastrointestinal-brain axis secretes a variety of different anorexigenic signals, such as uroguanylin, glucagon-like peptide-1, amylin, or cholecystokinin, which can alleviate the resistance to leptin action. Moreover, alternative mechanism such as pharmacokinetics, proteostasis, the role of specific kinases, chaperones, ER stress and neonatal feeding modifications are also implicated in leptin resistance. This review will cover the current knowledge regarding the interaction of leptin with different endocrine factors from the gastrointestinal-brain axis and other novel mechanisms that improve leptin sensitivity in obesity.
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Affiliation(s)
- Veronica Pena-Leon
- Grupo Fisiopatología Endocrina, Departamento de Endocrinología, Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS/SERGAS), Santiago de Compostela, Travesía da Choupana s/n, 15706 Santiago de Compostela, Spain
| | - Raquel Perez-Lois
- Grupo Fisiopatología Endocrina, Departamento de Endocrinología, Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS/SERGAS), Santiago de Compostela, Travesía da Choupana s/n, 15706 Santiago de Compostela, Spain
| | - Maria Villalon
- Grupo Fisiopatología Endocrina, Departamento de Endocrinología, Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS/SERGAS), Santiago de Compostela, Travesía da Choupana s/n, 15706 Santiago de Compostela, Spain
| | - Eva Prida
- Translational Endocrinology group, Endocrinology Section, Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (IDIS/CHUS), Santiago de Compostela, Travesía da Choupana s/n, 15706 Santiago de Compostela, Spain
| | - Diego Muñoz-Moreno
- Translational Endocrinology group, Endocrinology Section, Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (IDIS/CHUS), Santiago de Compostela, Travesía da Choupana s/n, 15706 Santiago de Compostela, Spain
| | - Johan Fernø
- Hormone Laboratory, Department of Biochemistry and Pharmacology, Haukeland University Hospital, 5201 Bergen, Norway
| | - Mar Quiñones
- Grupo Fisiopatología Endocrina, Departamento de Endocrinología, Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS/SERGAS), Santiago de Compostela, Travesía da Choupana s/n, 15706 Santiago de Compostela, Spain; CIBER de Fisiopatología de la Obesidad y la Nutrición, Instituto de Salud Carlos III, Madrid, Spain
| | - Omar Al-Massadi
- Translational Endocrinology group, Endocrinology Section, Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (IDIS/CHUS), Santiago de Compostela, Travesía da Choupana s/n, 15706 Santiago de Compostela, Spain; CIBER de Fisiopatología de la Obesidad y la Nutrición, Instituto de Salud Carlos III, Madrid, Spain.
| | - Luisa M Seoane
- Grupo Fisiopatología Endocrina, Departamento de Endocrinología, Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS/SERGAS), Santiago de Compostela, Travesía da Choupana s/n, 15706 Santiago de Compostela, Spain; CIBER de Fisiopatología de la Obesidad y la Nutrición, Instituto de Salud Carlos III, Madrid, Spain.
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2
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Leng L, Yuan Z, Su X, Chen Z, Yang S, Chen M, Zhuang K, Lin H, Sun H, Li H, Xue M, Xu J, Yan J, Chen Z, Yuan T, Zhang J. Hypothalamic Menin regulates systemic aging and cognitive decline. PLoS Biol 2023; 21:e3002033. [PMID: 36928253 PMCID: PMC10019680 DOI: 10.1371/journal.pbio.3002033] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 02/09/2023] [Indexed: 03/18/2023] Open
Abstract
Aging is a systemic process, which is a risk factor for impaired physiological functions, and finally death. The molecular mechanisms driving aging process and the associated cognitive decline are not fully understood. The hypothalamus acts as the arbiter that orchestrates systemic aging through neuroinflammatory signaling. Our recent findings revealed that Menin plays important roles in neuroinflammation and brain development. Here, we found that the hypothalamic Menin signaling diminished in aged mice, which correlates with systemic aging and cognitive deficits. Restoring Menin expression in ventromedial nucleus of hypothalamus (VMH) of aged mice extended lifespan, improved learning and memory, and ameliorated aging biomarkers, while inhibiting Menin in VMH of middle-aged mice induced premature aging and accelerated cognitive decline. We further found that Menin epigenetically regulates neuroinflammatory and metabolic pathways, including D-serine metabolism. Aging-associated Menin reduction led to impaired D-serine release by VMH-hippocampus neural circuit, while D-serine supplement rescued cognitive decline in aged mice. Collectively, VMH Menin serves as a key regulator of systemic aging and aging-related cognitive decline.
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Affiliation(s)
- Lige Leng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China
- * E-mail: (LL); (JZ)
| | - Ziqi Yuan
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Xiao Su
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Zhenlei Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Shangchen Yang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Meiqin Chen
- College of Basic Medicine, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Kai Zhuang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Hui Lin
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Hao Sun
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Huifang Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Maoqiang Xue
- Department of Basic Medical Science, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Jun Xu
- Institute for AI in Medicine, School of Automation, Nanjing University of Information Science and Technology, Nanjing, China
| | - Jingqi Yan
- Center for Gene Regulation in Health and Disease, Cleveland State University, Cleveland, Ohio, United States of America
| | - Zhenyi Chen
- Department of Anesthesiology, First Affiliated Hospital of Xiamen University, Xiamen, Fujian, China
| | - Tifei Yuan
- Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai China
| | - Jie Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China
- Department of Anesthesiology, First Affiliated Hospital of Xiamen University, Xiamen, Fujian, China
- * E-mail: (LL); (JZ)
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3
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Misch M, Puthanveetil P. The Head-to-Toe Hormone: Leptin as an Extensive Modulator of Physiologic Systems. Int J Mol Sci 2022; 23:ijms23105439. [PMID: 35628271 PMCID: PMC9141226 DOI: 10.3390/ijms23105439] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/30/2022] [Accepted: 05/10/2022] [Indexed: 12/12/2022] Open
Abstract
Leptin is a well-known hunger-sensing peptide hormone. The role of leptin in weight gain and metabolic homeostasis has been explored for the past two decades. In this review, we have tried to shed light upon the impact of leptin signaling on health and diseases. At low or moderate levels, this peptide hormone supports physiological roles, but at chronically higher doses exhibits detrimental effects on various systems. The untoward effects we observe with chronically higher levels of leptin are due to their receptor-mediated effect or due to leptin resistance and are not well studied. This review will help us in understanding the non-anorexic roles of leptin, including their contribution to the metabolism of various systems and inflammation. We will be able to get an alternative perspective regarding the physiological and pathological roles of this mysterious peptide hormone.
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Affiliation(s)
- Monica Misch
- Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL 60515, USA;
| | - Prasanth Puthanveetil
- Department of Pharmacology, College of Graduate Studies, Midwestern University, Downers Grove, IL 60515, USA
- Correspondence: ; Tel.: +1-630-960-3935
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4
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Arrigoni S, Le Foll C, Cabak A, Lundh S, Raun K, John LM, Lutz TA. A selective role for receptor activity-modifying proteins in subchronic action of the amylin selective receptor agonist NN1213 compared with salmon calcitonin on body weight and food intake in male mice. Eur J Neurosci 2021; 54:4863-4876. [PMID: 34189795 PMCID: PMC8457108 DOI: 10.1111/ejn.15376] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/22/2021] [Accepted: 06/23/2021] [Indexed: 12/19/2022]
Abstract
The role of receptor activity‐modifying proteins (RAMPs) in modulating the pharmacological effects of an amylin receptor selective agonist (NN1213) or the dual amylin–calcitonin receptor agonist (DACRA), salmon calcitonin (sCT), was tested in three RAMP KO mouse models, RAMP1, RAMP3 and RAMP1/3 KO. Male wild‐type (WT) and knockout (KO) littermate mice were fed a 45% high‐fat diet for 20 weeks prior to the 3‐week treatment period. A decrease in body weight after NN1213 was observed in all WT mice, whereas sCT had no effect. The absence of RAMP1 had no significant effect on NN1213 efficacy, and sCT was still inactive. However, the absence of RAMP3 impeded NN1213 efficacy but improved sCT efficacy. Similar results were observed in RAMP1/3 KO suggesting that the amylin receptor 3 (AMY3 = CTR + RAMP3) is necessary for NN1213's maximal action on body weight and food intake and that the lack of AMY3 allowed sCT to be active. These results suggest that the chronic use of DACRA such as sCT can have unfavourable effect on body weight loss in mice (which differs from the situation in rats), whereas the use of the amylin receptor selective agonist does not. AMY3 seems to play a crucial role in modulating the action of these two compounds, but in opposite directions. The assessment of a long‐term effect of amylin and DACRA in different rodent models is necessary to understand potential physiological beneficial and unfavourable effects on weight loss before its transition to clinical trials.
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Affiliation(s)
- Soraya Arrigoni
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Andrea Cabak
- Global Research, Novo Nordisk AS, Måløv, Denmark
| | - Sofia Lundh
- Global Research, Novo Nordisk AS, Måløv, Denmark
| | - Kirsten Raun
- Global Research, Novo Nordisk AS, Måløv, Denmark
| | - Linu M John
- Global Research, Novo Nordisk AS, Måløv, Denmark
| | - Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
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5
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New Insights of SF1 Neurons in Hypothalamic Regulation of Obesity and Diabetes. Int J Mol Sci 2021; 22:ijms22126186. [PMID: 34201257 PMCID: PMC8229730 DOI: 10.3390/ijms22126186] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/04/2021] [Accepted: 06/05/2021] [Indexed: 12/16/2022] Open
Abstract
Despite the substantial role played by the hypothalamus in the regulation of energy balance and glucose homeostasis, the exact mechanisms and neuronal circuits underlying this regulation remain poorly understood. In the last 15 years, investigations using transgenic models, optogenetic, and chemogenetic approaches have revealed that SF1 neurons in the ventromedial hypothalamus are a specific lead in the brain’s ability to sense glucose levels and conduct insulin and leptin signaling in energy expenditure and glucose homeostasis, with minor feeding control. Deletion of hormonal receptors, nutritional sensors, or synaptic receptors in SF1 neurons triggers metabolic alterations mostly appreciated under high-fat feeding, indicating that SF1 neurons are particularly important for metabolic adaptation in the early stages of obesity. Although these studies have provided exciting insight into the implications of hypothalamic SF1 neurons on whole-body energy homeostasis, new questions have arisen from these results. Particularly, the existence of neuronal sub-populations of SF1 neurons and the intricate neurocircuitry linking these neurons with other nuclei and with the periphery. In this review, we address the most relevant studies carried out in SF1 neurons to date, to provide a global view of the central role played by these neurons in the pathogenesis of obesity and diabetes.
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Sabatini PV, Wang J, Rupp AC, Affinati AH, Flak JN, Li C, Olson DP, Myers MG. tTARGIT AAVs mediate the sensitive and flexible manipulation of intersectional neuronal populations in mice. eLife 2021; 10:66835. [PMID: 33704065 PMCID: PMC8026215 DOI: 10.7554/elife.66835] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 03/10/2021] [Indexed: 12/20/2022] Open
Abstract
While Cre-dependent viral systems permit the manipulation of many neuron types, some cell populations cannot be targeted by a single DNA recombinase. Although the combined use of Flp and Cre recombinases can overcome this limitation, insufficient recombinase activity can reduce the efficacy of existing Cre+Flp-dependent viral systems. We developed a sensitive dual recombinase-activated viral approach: tTA-driven Recombinase-Guided Intersectional Targeting (tTARGIT) adeno-associated viruses (AAVs). tTARGIT AAVs utilize a Flp-dependent tetracycline transactivator (tTA) ‘Driver’ AAV and a tetracycline response element-driven, Cre-dependent ‘Payload’ AAV to express the transgene of interest. We employed this system in Slc17a6FlpO;LeprCre mice to manipulate LepRb neurons of the ventromedial hypothalamus (VMH; LepRbVMH neurons) while omitting neighboring LepRb populations. We defined the circuitry of LepRbVMH neurons and roles for these cells in the control of food intake and energy expenditure. Thus, the tTARGIT system mediates robust recombinase-sensitive transgene expression, permitting the precise manipulation of previously intractable neural populations. The brain contains hundreds of types of neurons, which differ in size, shape and behavior. But neuroscientists often wish to study individual neuronal types in isolation. They are able to do this with the aid of a toolkit made up of two parts: viral vectors and genetically modified mice. Viral vectors are viruses that have been modified so that they are no longer harmful and can instead be used to introduce genetic material into cells on demand. To create a viral vector, the virus’ own genetic material is replaced with a ‘cargo’ gene, such as the gene for a fluorescent protein. The virus is then introduced into a new host such as a mouse. Importantly, the virus only produces the protein encoded by its ‘cargo’ gene if it is inside a cell that also contains one of two specific enzymes. These enzymes are called Cre and Flp. This is where the second part of the toolkit comes in. Mice can be genetically engineered to produce either Cre or Flp exclusively in specific cell types. By introducing a viral vector into mice that produce either Cre or Flp only in one particular type of neuron, researchers can limit the activity of the cargo gene to that neuronal type. But sometimes even this approach is not selective enough. Researchers may wish to limit the activity of the cargo gene to a subpopulation of cells that produce Cre or Flp. Or they may wish to target only Cre- or Flp-producing cells in a small area of the brain, while leaving cells in neighboring areas unaffected. Sabatini et al. have now overcome this limitation by developing and testing a new set of viral vectors that are active only in neurons that produce both Cre and Flp. The vectors are called tTARGIT AAVs and allow researchers to target cells more precisely than was possible with the previous version of the toolkit. Sabatini et al. show tTARGIT AAVs in action by using them to identify a group of neurons that control how much energy mice use and how much food they eat. As well as applying the vectors to their own research on obesity, Sabatini et al. have also made them freely available for other researchers to use in their own projects.
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Affiliation(s)
- Paul V Sabatini
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States
| | - Jine Wang
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States.,Chinese academy, College of Medical Science, China Three Gorges University, Yichang, China
| | - Alan C Rupp
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States
| | - Alison H Affinati
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States
| | - Jonathan N Flak
- Indiana Biosciences Research Institute, Indianapolis, United States
| | - Chien Li
- Novo Nordisk Research Center, Seattle, United States
| | - David P Olson
- Department of Pediatrics, University of Michigan, Ann Arbor, United States.,Department of Molecular and Integrative Physiology, Ann Arbor, United States
| | - Martin G Myers
- Department of Internal Medicine, University of Michigan, Ann Arbor, United States.,Department of Molecular and Integrative Physiology, Ann Arbor, United States
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Cheng AA, Li W, Walker TM, Silvers C, Arendt LM, Hernandez LL. Investigating the complex interplay between genotype and high-fat-diet feeding in the lactating mammary gland using the Tph1 and Ldlr knockout models. Am J Physiol Endocrinol Metab 2021; 320:E438-E452. [PMID: 33427054 PMCID: PMC7988787 DOI: 10.1152/ajpendo.00456.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 12/15/2020] [Accepted: 12/18/2020] [Indexed: 12/12/2022]
Abstract
Obesity is a prevailing problem across the globe. Women who are obese have difficulty initiating and sustaining lactation. However, the impact of genetics and diet on breastfeeding outcomes is understudied. Here we explore the effect of diet and genotype on lactation. We utilized the low-density lipoprotein receptor (Ldlr-KO) transgenic mouse model as an obesity and hypercholesterolemia model. Additionally, we used the tryptophan hydroxylase 1 (Tph1-KO) mouse, recently identified as a potential anti-obesogenic model, to investigate if addition of Tph1-KO could ameliorate negative effects of obesity in Ldlr-KO mice. We created a novel transgenic mouse line by combining the Ldlr and Tph1 [double knockout (DKO)] mice to study the interaction between the two genotypes. Female mice were fed a low-fat diet (LFD; 10% fat) or high-fat diet (HFD; 60% fat) from 3 wk of age through early [lactation day 3 (L3)] or peak lactation [lactation day 11 (L11)]. After 4 wk of consuming either LFD or HFD, female mice were bred. On L2 and L10, dams were milked to investigate the effect of diet and genotype on milk composition. Dams were euthanized on L3 or L11. There was no impact of diet or genotype on milk protein or triglycerides (TGs) on L2; however, by L10, Ldlr-KO and DKO dams had increased TG levels in milk. RNA-sequencing of L11 mammary glands demonstrated Ldlr-KO dams fed HFD displayed enrichment of genes involved in immune system pathways. Interestingly, the DKO may alter vesicle budding and biogenesis during lactation. We also quantified macrophages by immunostaining for F4/80+ cells at L3 and L11. Diet played a significant role on L3 (P = 0.013), but genotype played a role at L11 (P < 0.0001) on numbers of F4/80+ cells. Thus the impact of diet and genotype on lactation differs depending on stage of lactation, illustrating complexities of understanding the intersection of these parameters.NEW & NOTEWORTHY We have created a novel mouse model that is focused on understanding the intersection of diet and genotype on mammary gland function during lactation.
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Affiliation(s)
- Adrienne A Cheng
- Department of Nutritional Sciences, University of Wisconsin, Madison, Wisconsin
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, Wisconsin
| | - Wenli Li
- US Department of Agriculture-Dairy Forage, Madison, Wisconsin
| | - Teresa M Walker
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, Wisconsin
| | - Caylee Silvers
- Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin
| | - Lisa M Arendt
- Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin
| | - Laura L Hernandez
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, Wisconsin
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8
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Pereira S, Cline DL, Glavas MM, Covey SD, Kieffer TJ. Tissue-Specific Effects of Leptin on Glucose and Lipid Metabolism. Endocr Rev 2021; 42:1-28. [PMID: 33150398 PMCID: PMC7846142 DOI: 10.1210/endrev/bnaa027] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Indexed: 12/18/2022]
Abstract
The discovery of leptin was intrinsically associated with its ability to regulate body weight. However, the effects of leptin are more far-reaching and include profound glucose-lowering and anti-lipogenic effects, independent of leptin's regulation of body weight. Regulation of glucose metabolism by leptin is mediated both centrally and via peripheral tissues and is influenced by the activation status of insulin signaling pathways. Ectopic fat accumulation is diminished by both central and peripheral leptin, an effect that is beneficial in obesity-associated disorders. The magnitude of leptin action depends upon the tissue, sex, and context being examined. Peripheral tissues that are of particular relevance include the endocrine pancreas, liver, skeletal muscle, adipose tissues, immune cells, and the cardiovascular system. As a result of its potent metabolic activity, leptin is used to control hyperglycemia in patients with lipodystrophy and is being explored as an adjunct to insulin in patients with type 1 diabetes. To fully understand the role of leptin in physiology and to maximize its therapeutic potential, the mechanisms of leptin action in these tissues needs to be further explored.
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Affiliation(s)
- Sandra Pereira
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Daemon L Cline
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Maria M Glavas
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Scott D Covey
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Timothy J Kieffer
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada.,Department of Surgery, University of British Columbia, Vancouver, Canada.,School of Biomedical Engineering, University of British Columbia, Vancouver, Canada
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9
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Zhu C, Jiang Z, Xu Y, Cai ZL, Jiang Q, Xu Y, Xue M, Arenkiel BR, Wu Q, Shu G, Tong Q. Profound and redundant functions of arcuate neurons in obesity development. Nat Metab 2020; 2:763-774. [PMID: 32719538 PMCID: PMC7687864 DOI: 10.1038/s42255-020-0229-2] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 05/28/2020] [Indexed: 02/06/2023]
Abstract
The current obesity epidemic faces a lack of mechanistic insights. It is known that the acute activity changes of a growing number of brain neurons rapidly alter feeding behaviour; however, how these changes translate to obesity development and the fundamental mechanism underlying brain neurons in controlling body weight remain elusive. Here, we show that chronic activation of hypothalamic arcuate GABAergic (GABA+), agouti-related protein (AgRP) neurons or arcuate non-AgRP GABA+ neurons leads to obesity, which is similar to the obese phenotype observed in ob/ob mice. Conversely, chronic inhibition of arcuate GABA+, but not AgRP, neurons reduces ageing-related weight gain and corrects ob/ob obesity. These results demonstrate that the modulation of Arc GABA+ neuron activity is a fundamental mechanism of body-weight regulation, and that arcuate GABA+ neurons are the major mediator of leptin action, with a profound and redundant role in obesity development.
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Affiliation(s)
- Canjun Zhu
- Brown Foundation Institute of Molecular Medicine of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, College of Animal Science, South China Agricultural University, Guangdong, China
| | - Zhiying Jiang
- Brown Foundation Institute of Molecular Medicine of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Yuanzhong Xu
- Brown Foundation Institute of Molecular Medicine of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Zhao-Lin Cai
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
| | - Qingyan Jiang
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, College of Animal Science, South China Agricultural University, Guangdong, China
| | - Yong Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Mingshan Xue
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
- Department of Molecular and Human Genetics and Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Benjamin R Arenkiel
- Department of Molecular and Human Genetics and Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Qi Wu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Gang Shu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, College of Animal Science, South China Agricultural University, Guangdong, China.
| | - Qingchun Tong
- Brown Foundation Institute of Molecular Medicine of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA.
- Department of Neurobiology and Anatomy of McGovern Medical School and Program in Neuroscience of MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA.
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10
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Foll CL, Lutz TA. Systemic and Central Amylin, Amylin Receptor Signaling, and Their Physiological and Pathophysiological Roles in Metabolism. Compr Physiol 2020; 10:811-837. [PMID: 32941692 DOI: 10.1002/cphy.c190034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This article in the Neural and Endocrine Section of Comprehensive Physiology discusses the physiology and pathophysiology of the pancreatic hormone amylin. Shortly after its discovery in 1986, amylin has been shown to reduce food intake as a satiation signal to limit meal size. Amylin also affects food reward, sensitizes the brain to the catabolic actions of leptin, and may also play a prominent role in the development of certain brain areas that are involved in metabolic control. Amylin may act at different sites in the brain in addition to the area postrema (AP) in the caudal hindbrain. In particular, the sensitizing effect of amylin on leptin action may depend on a direct interaction in the hypothalamus. The concept of central pathways mediating amylin action became more complex after the discovery that amylin is also synthesized in certain hypothalamic areas but the interaction between central and peripheral amylin signaling remains currently unexplored. Amylin may also play a dominant pathophysiological role that is associated with the aggregation of monomeric amylin into larger, cytotoxic molecular entities. This aggregation in certain species may contribute to the development of type 2 diabetes mellitus but also cardiovascular disease. Amylin receptor pharmacology is complex because several distinct amylin receptor subtypes have been described, because other neuropeptides [e.g., calcitonin gene-related peptide (CGRP)] can also bind to amylin receptors, and because some components of the functional amylin receptor are also used for other G-protein coupled receptor (GPCR) systems. © 2020 American Physiological Society. Compr Physiol 10:811-837, 2020.
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Affiliation(s)
- Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
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Harris RBS. Loss of leptin receptor-expressing cells in the hindbrain decreases forebrain leptin sensitivity. Am J Physiol Endocrinol Metab 2020; 318:E806-E816. [PMID: 32228323 PMCID: PMC7272723 DOI: 10.1152/ajpendo.00020.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/18/2020] [Accepted: 03/24/2020] [Indexed: 01/12/2023]
Abstract
Previous studies indicate that inhibition of food intake by leptin is mediated by an integrated response to activation of hypothalamic and hindbrain receptors. This study tested whether loss of hindbrain leptin receptor signaling changed sensitivity to forebrain leptin. Injections of leptin-conjugated saporin (Lep-Sap) into the medial nucleus of the solitary tract (NTS) were used to destroy hindbrain leptin receptor-expressing neurons of male Sprague-Dawley rats. Controls were injected with saporin conjugated with a nonsense peptide (Blk-Sap). Lep-Sap had no effect on daily food intake or body weight, but expression of phosphorylated signal transducer and activator of transcription 3 (pSTAT3) in the NTS following a peripheral injection of leptin was abolished 26 days after Lep-Sap injections. To test forebrain leptin sensitivity, Lep-Sap and Blk-Sap rats received third-ventricle injections of 0, 0.05, 0.1, 0.25, or 0.5 μg leptin. Food intake was inhibited by 0.25 and 0.5 μg leptin in Blk-Sap rats, but there was no significant effect of leptin on food intake of Lep-Sap rats. There was no difference in hypothalamic pSTAT3 in unstimulated conditions, but pSTAT3 was lower in the dorsomedial region of the ventromedial nucleus of the hypothalamus (VMH) of Lep-Sap rats compared with Blk-Sap rats following a third-ventricle injection of 0.25 μg leptin. These results are consistent with previous data showing that loss of VMH leptin receptor-expressing cells prevents weight loss caused by fourth-ventricle leptin infusion and show that the integrated response between the hindbrain and forebrain is heavily dependent on leptin activity in the VMH.
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Affiliation(s)
- Ruth B S Harris
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, Georgia
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