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Fox EA, Serlin HK. Gaps in our understanding of how vagal afferents to the small intestinal mucosa detect luminal stimuli. Am J Physiol Regul Integr Comp Physiol 2024; 327:R173-R187. [PMID: 38860288 DOI: 10.1152/ajpregu.00252.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 05/10/2024] [Accepted: 05/24/2024] [Indexed: 06/12/2024]
Abstract
Vagal afferents to the gastrointestinal tract are crucial for the regulation of food intake, signaling negative feedback that contributes to satiation and positive feedback that produces appetition and reward. Vagal afferents to the small intestinal mucosa contribute to this regulation by sensing luminal stimuli and reporting this information to the brain. These afferents respond to mechanical, chemical, thermal, pH, and osmolar stimuli, as well as to bacterial products and immunogens. Surprisingly, little is known about how these stimuli are transduced by vagal mucosal afferents or how their transduction is organized among these afferents' terminals. Furthermore, the effects of stimulus concentration ranges or physiological stimuli on vagal activity have not been examined for some of these stimuli. Also, detection of luminal stimuli has rarely been examined in rodents, which are most frequently used for studying small intestinal innervation. Here we review what is known about stimulus detection by vagal mucosal afferents and illustrate the complexity of this detection using nutrients as an exemplar. The accepted model proposes that nutrients bind to taste receptors on enteroendocrine cells (EECs), which excite them, causing the release of hormones that stimulate vagal mucosal afferents. However, evidence reviewed here suggests that although this model accounts for many aspects of vagal signaling about nutrients, it cannot account for all aspects. A major goal of this review is therefore to evaluate what is known about nutrient absorption and detection and, based on this evaluation, identify candidate mucosal cells and structures that could cooperate with EECs and vagal mucosal afferents in stimulus detection.
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Affiliation(s)
- Edward A Fox
- Behavioral Neurogenetics Laboratory, Department of Psychological Sciences, Purdue University, West Lafayette, Indiana, United States
| | - Hannah K Serlin
- Behavioral Neurogenetics Laboratory, Department of Psychological Sciences, Purdue University, West Lafayette, Indiana, United States
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2
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Elkattawy HA, Mahmoud SM, Hassan AES, Behiry A, Ebrahim HA, Ibrahim AM, Zaghamir DEF, El-Sherbiny M, El-Sayed SF. Vagal Stimulation Ameliorates Non-Alcoholic Fatty Liver Disease in Rats. Biomedicines 2023; 11:3255. [PMID: 38137476 PMCID: PMC10741668 DOI: 10.3390/biomedicines11123255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 11/30/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
BACKGROUND The harmful consequences of non-alcoholic fatty liver disease (NAFLD) are posing an increasing threat to public health as the incidence of diabetes and obesity increases globally. A non-invasive treatment with a range of autonomic and metabolic benefits is transcutaneous vagus nerve stimulation (tVNS). AIM OF THE STUDY To investigate the possible preventive impacts of VNS against adult rats' NAFLD caused by a high-fat diet (HFD) and to clarify the underlying mechanisms. METHODS A total of thirty-two adult male rats were split into two groups: the HFD-induced NAFLD group (n = 24) and the control normal group (n = 8). The obesogenic diet was maintained for 12 weeks to induce hepatic steatosis. The HFD-induced NAFLD group (n = 24) was separated into three groups: the group without treatment (n = 8), the group with sham stimulation (n = 8), and the group with VNS treatment (n = 8). VNS was delivered for 30 min per day for 6 weeks after the establishment of NAFLD using a digital TENS device. The subsequent assessments included hepatic triglyceride, cholesterol content, serum lipid profile, and liver function testing. In this context, inflammatory biomarkers (TNF-α, IL-6) and hepatic oxidative stress (MDA, SOD, and GPx) were also assessed. To clarify the possible mechanisms behind the protective benefits of VNS, additional histological inspection and immunohistochemistry analysis of TNF-α and Caspase-3 were performed. RESULTS In the NAFLD-affected obese rats, VNS markedly decreased the rats' body mass index (BMI) and abdominal circumference (AC). Liver function markers (albumin, ALT, and AST) and the serum lipid profile-which included a notable decrease in the amounts of hepatic triglycerides and cholesterol-were both markedly improved. Additionally, oxidative stress and inflammatory indicators showed a considerable decline with VNS. Notably, the liver tissues examined by histopathologists revealed that there is evidence of the protective impact of VNS on the oxidative and inflammatory states linked to HFD-induced NAFLD while maintaining the architectural and functional condition of the liver. CONCLUSIONS Our findings suggest that VNS may represent a promising therapeutic candidate for managing NAFLD induced by obesity. It can be considered to be an effective adjuvant physiological intervention for the obese population with NAFLD to spare the liver against obesity-induced deleterious injury.
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Affiliation(s)
- Hany A. Elkattawy
- Department of Basic Medical Sciences, College of Medicine, AlMaarefa University, Riyadh 11579, Saudi Arabia;
- Medical Physiology Department, College of Medicine, Zagazig University, Zagazig P.O. Box 44519, Egypt; (A.E.-S.H.); (S.F.E.-S.)
| | - Samar Mortada Mahmoud
- Department of Human Anatomy and Embryology, College of Medicine, Zagazig University, Zagazig P.O. Box 44519, Egypt;
| | - Ahmed El-Sayed Hassan
- Medical Physiology Department, College of Medicine, Zagazig University, Zagazig P.O. Box 44519, Egypt; (A.E.-S.H.); (S.F.E.-S.)
- Department of Basic Medical Sciences, College of Medicine, Sulaiman Al-Rajhi University, Bukayriah 51941, Saudi Arabia
| | - Ahmed Behiry
- Department of Tropical Medicine and Endemic Diseases, College of Medicine, Zagazig University, Zagazig P.O. Box 44519, Egypt;
| | - Hasnaa Ali Ebrahim
- Department of Basic Medical Sciences, College of Medicine, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia;
| | - Ateya Megahed Ibrahim
- Department of Nursing, College of Applied Medical Sciences, Prince Sattam bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia; (A.M.I.); (D.E.F.Z.)
- Department of Family and Community Health Nursing, Faculty of Nursing, Port Said University, Port Said P.O. Box 42511, Egypt
| | - Donia Elsaid Fathi Zaghamir
- Department of Nursing, College of Applied Medical Sciences, Prince Sattam bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia; (A.M.I.); (D.E.F.Z.)
- Department of Pediatric Nursing, Faculty of Nursing, Port Said University, Port Said P.O. Box 42511, Egypt
| | - Mohamed El-Sherbiny
- Department of Basic Medical Sciences, College of Medicine, AlMaarefa University, Riyadh 11579, Saudi Arabia;
| | - Sherein F. El-Sayed
- Medical Physiology Department, College of Medicine, Zagazig University, Zagazig P.O. Box 44519, Egypt; (A.E.-S.H.); (S.F.E.-S.)
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Leyderman M, Wilmore JR, Shope T, Cooney RN, Urao N. Impact of intestinal microenvironments in obesity and bariatric surgery on shaping macrophages. IMMUNOMETABOLISM (COBHAM, SURREY) 2023; 5:e00033. [PMID: 38037591 PMCID: PMC10683977 DOI: 10.1097/in9.0000000000000033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 10/26/2023] [Indexed: 12/02/2023]
Abstract
Obesity is associated with alterations in tissue composition, systemic cellular metabolism, and low-grade chronic inflammation. Macrophages are heterogenous innate immune cells ubiquitously localized throughout the body and are key components of tissue homeostasis, inflammation, wound healing, and various disease states. Macrophages are highly plastic and can switch their phenotypic polarization and change function in response to their local environments. Here, we discuss how obesity alters the intestinal microenvironment and potential key factors that can influence intestinal macrophages as well as macrophages in other organs, including adipose tissue and hematopoietic organs. As bariatric surgery can induce metabolic adaptation systemically, we discuss the potential mechanisms through which bariatric surgery reshapes macrophages in obesity.
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Affiliation(s)
- Michael Leyderman
- Department of Pharmacology, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Joel R. Wilmore
- Department of Microbiology and Immunology, State University of New York Upstate Medical University, Syracuse, NY, USA
- Sepsis Interdisciplinary Research Center, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Timothy Shope
- Department of Surgery, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Robert N. Cooney
- Sepsis Interdisciplinary Research Center, State University of New York Upstate Medical University, Syracuse, NY, USA
- Department of Surgery, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Norifumi Urao
- Department of Pharmacology, State University of New York Upstate Medical University, Syracuse, NY, USA
- Sepsis Interdisciplinary Research Center, State University of New York Upstate Medical University, Syracuse, NY, USA
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4
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Samovski D, Jacome-Sosa M, Abumrad NA. Fatty Acid Transport and Signaling: Mechanisms and Physiological Implications. Annu Rev Physiol 2023; 85:317-337. [PMID: 36347219 DOI: 10.1146/annurev-physiol-032122-030352] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Long-chain fatty acids (FAs) are components of plasma membranes and an efficient fuel source and also serve as metabolic regulators through FA signaling mediated by membrane FA receptors. Impaired tissue FA uptake has been linked to major complications of obesity, including insulin resistance, cardiovascular disease, and type 2 diabetes. Fatty acid interactions with a membrane receptor and the initiation of signaling can modify pathways related to nutrient uptake and processing, cell proliferation or differentiation, and secretion of bioactive factors. Here, we review the major membrane receptors involved in FA uptake and FA signaling. We focus on two types of membrane receptors for long-chain FAs: CD36 and the G protein-coupled FA receptors FFAR1 and FFAR4. We describe key signaling pathways and metabolic outcomes for CD36, FFAR1, and FFAR4 and highlight the parallels that provide insight into FA regulation of cell function.
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Affiliation(s)
- Dmitri Samovski
- Center for Human Nutrition, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA;
| | - Miriam Jacome-Sosa
- Center for Human Nutrition, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA;
| | - Nada A Abumrad
- Center for Human Nutrition, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA; .,Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, USA
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Sengani M, V B, Banerjee M, Choudhury AA, Chakraborty S, Ramasubbu K, Rajeswari V D, Al Obaid S, Alharbi SA, Subramani B, Brindhadevi K. Evaluation of the anti-diabetic effect of biogenic silver nanoparticles and intervention in PPARγ gene regulation. ENVIRONMENTAL RESEARCH 2022; 215:114408. [PMID: 36154863 DOI: 10.1016/j.envres.2022.114408] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/03/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
The current study demonstrated a green, friendly, low-cost biosynthesis of silver nanoparticles (AgNPs) from Kigelia africana leaves (Lam.) Benth. extract (KAE) as both a major capping and reducing agent. The produced AgNPs were characterized using a variety of analytical methods, like the X-ray powder diffraction (XRD), HRTEM, Fourier transforms infrared (FTIR), and UV-Vis spectrophotometer. The formation of AgNPs with maximum absorbance at max = 435 nm was endorsed by surface plasmon resonance. FTIR analysis revealed that biological macromolecules of KAE were involved in the stabilization and synthesis of AgNPs. At the same time, HRTEM images revealed that the average particle size of the spherical AgNPs ranged from about 25 nm to 35 nm. Further, cytotoxicity assessment of AgNPs was done using the RINm5F insulinoma cell line with an MTT assay. Followed by, the RINm5F insulinoma cells treated with AgNPs and KAE, the expression of the Peroxisome proliferator-activated receptor gamma (PPARγ) gene was accessed. The results showed gene expression was upregulated in the RINm5F insulinoma cell line thus confirming AgNPs and KAE anti-diabetic efficacy. Furthermore, the findings show that nanotechnology has enhanced the effectiveness of current methodologies in gene expression and regulation which has contributed to the emergence of different forms of advanced regulatory systems.
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Affiliation(s)
- Manimegalai Sengani
- Department of Biotechnology, College of Science and Humanities, SRM Institute of Science and Technology, Ramapuram, Chennai, 600087, India
| | - Bavithra V
- School of Biosciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Manosi Banerjee
- School of Biosciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Abbas Alam Choudhury
- School of Biosciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Shreya Chakraborty
- School of Biosciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Kanagavalli Ramasubbu
- School of Biosciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Devi Rajeswari V
- School of Biosciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India.
| | - Sami Al Obaid
- Department of Botany and Microbiology, College of Science, King Saud University, PO Box -2455, Riyadh, 11451, Saudi Arabia
| | - Sulaiman Ali Alharbi
- Department of Botany and Microbiology, College of Science, King Saud University, PO Box -2455, Riyadh, 11451, Saudi Arabia
| | - Baskaran Subramani
- Division of Hematology and Oncology, Department of Medicine, Mays Cancer Center, University of Texas Health, San Antonio, TX, USA
| | - Kathirvel Brindhadevi
- Center for Transdisciplinary Research (CFTR), Department of Pharmacology, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, India.
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Ma Y, Liu S, Jun H, Wu J. CHRNA2: a new paradigm in beige thermoregulation and metabolism. Trends Cell Biol 2021; 32:479-489. [PMID: 34952750 DOI: 10.1016/j.tcb.2021.11.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/19/2021] [Accepted: 11/25/2021] [Indexed: 02/07/2023]
Abstract
The contribution of thermogenic adipocytes to maintain systemic metabolic homeostasis has been increasingly appreciated in recent years. It is now recognized that different types (e.g., brown, beige) and subtypes of thermogenic adipocytes may arise from various developmental origins. In addition to the adrenergic pathway, other signals can activate thermogenesis, including paracrine communication between immune cells within the adipose tissue niche and thermogenic adipocytes. In this opinion article we highlight the recently discovered beige-selective signaling between acetylcholine from immune cells and cholinergic receptor nicotinic alpha 2 subunit (CHRNA2) in activated beige adipocytes. We present our current knowledge of how this previously unrecognized adipose non-neuronal cholinergic signaling pathway mediates beige thermoregulation, and discuss its impact on whole-body fitness and its therapeutic potential as a novel target for combating metabolic disease.
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Affiliation(s)
- Yingxu Ma
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Shanshan Liu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Heejin Jun
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jun Wu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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Bob-Manuel J, Gautron L. Detection of G Protein-coupled Receptor Expression in Mouse Vagal Afferent Neurons using Multiplex In Situ Hybridization. J Vis Exp 2021:10.3791/62945. [PMID: 34605820 PMCID: PMC9235148 DOI: 10.3791/62945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
This study describes a protocol for the multiplex in situ hybridization (ISH) of the mouse jugular-nodose ganglia, with a particular emphasis on detecting the expression of G protein-coupled receptors (GPCRs). Formalin-fixed jugular-nodose ganglia were processed with the RNAscope technology to simultaneously detect the expression of two representative GPCRs (cholecystokinin and ghrelin receptors) in combination with one marker gene of either nodose (paired-like homeobox 2b, Phox2b) or jugular afferent neurons (PR domain zinc finger protein 12, Prdm12). Labeled ganglia were imaged using confocal microscopy to determine the distribution and expression patterns of the aforementioned transcripts. Briefly, Phox2b afferent neurons were found to abundantly express the cholecystokinin receptor (Cck1r) but not the ghrelin receptor (Ghsr). A small subset of Prdm12 afferent neurons was also found to express Ghsr and/or Cck1r. Potential technical caveats in the design, processing, and interpretation of multiplex ISH are discussed. The approach described in this article may help scientists in generating accurate maps of the transcriptional profiles of vagal afferent neurons.
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Affiliation(s)
- Johnson Bob-Manuel
- Center for Hypothalamic Research and Department of Internal Medicine, UTSouthwestern Medical Center at Dallas
| | - Laurent Gautron
- Center for Hypothalamic Research and Department of Internal Medicine, UTSouthwestern Medical Center at Dallas;
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8
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Berland C, Small DM, Luquet S, Gangarossa G. Dietary lipids as regulators of reward processes: multimodal integration matters. Trends Endocrinol Metab 2021; 32:693-705. [PMID: 34148784 DOI: 10.1016/j.tem.2021.05.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 05/08/2021] [Accepted: 05/24/2021] [Indexed: 02/03/2023]
Abstract
The abundance of energy-dense and palatable diets in the modern food environment tightly contributes to the obesity pandemic. The reward circuit participates to the regulation of body homeostasis by integrating energy-related signals with neural substrates encoding cognitive and motivational components of feeding behaviors. Obesity and lipid-rich diets alter dopamine (DA) transmission leading to reward dysfunctions and food overconsumption. Recent reports indicate that dietary lipids can act, directly and indirectly, as functional modulators of the DA circuit. This raises the possibility that nutritional or genetic conditions affecting 'lipid sensing' mechanisms might lead to maladaptations of the DA system. Here, we discuss the most recent findings connecting dietary lipid sensing with DA signaling and its multimodal influence on circuits regulating food-reward processes.
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Affiliation(s)
- Chloé Berland
- Université de Paris, BFA, UMR 8251, CNRS, F-75013 Paris, France; Department of Medicine, The Naomi Berrie Diabetes Center, Columbia University, New York, NY 10032, USA
| | - Dana M Small
- Department of Psychiatry, and the Modern Diet and Physiology Research Center, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Serge Luquet
- Université de Paris, BFA, UMR 8251, CNRS, F-75013 Paris, France.
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Zubareva OE, Melik-Kasumov TB. The Gut–Brain Axis and Peroxisome Proliferator-Activated Receptors in the Regulation of Epileptogenesis. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021040013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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McDougle M, Quinn D, Diepenbroek C, Singh A, de la Serre C, de Lartigue G. Intact vagal gut-brain signalling prevents hyperphagia and excessive weight gain in response to high-fat high-sugar diet. Acta Physiol (Oxf) 2021; 231:e13530. [PMID: 32603548 PMCID: PMC7772266 DOI: 10.1111/apha.13530] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 01/02/2023]
Abstract
Aim The tools that have been used to assess the function of the vagus nerve lack specificity. This could explain discrepancies about the role of vagal gut‐brain signalling in long‐term control of energy balance. Here we use a validated approach to selectively ablate sensory vagal neurones that innervate the gut to determine the role of vagal gut‐brain signalling in the control of food intake, energy expenditure and glucose homoeostasis in response to different diets. Methods Rat nodose ganglia were injected bilaterally with either the neurotoxin saporin conjugated to the gastrointestinal hormone cholecystokinin (CCK), or unconjugated saporin as a control. Food intake, body weight, glucose tolerance and energy expenditure were measured in both groups in response to chow or high‐fat high‐sugar (HFHS) diet. Willingness to work for fat or sugar was assessed by progressive ratio for orally administered solutions, while post‐ingestive feedback was tested by measuring food intake after an isocaloric lipid or sucrose pre‐load. Results Vagal deafferentation of the gut increases meal number in lean chow‐fed rats. Switching to a HFHS diet exacerbates overeating and body weight gain. The breakpoint for sugar or fat solution did not differ between groups, suggesting that increased palatability may not drive HFHS‐induced hyperphagia. Instead, decreased satiation in response to intra‐gastric infusion of fat, but not sugar, promotes hyperphagia in CCK‐Saporin‐treated rats fed with HFHS diet. Conclusions We conclude that intact sensory vagal neurones prevent hyperphagia and exacerbation of weight gain in response to a HFHS diet by promoting lipid‐mediated satiation.
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Affiliation(s)
- Molly McDougle
- Department of Pharmacodynamics University of Florida Gainesville FL USA
- Center for Integrative Cardiovascular and Metabolic Disease University of Florida Gainesville FL USA
- The John B. Pierce Laboratory New Haven CT USA
| | | | - Charlene Diepenbroek
- The John B. Pierce Laboratory New Haven CT USA
- Department of Cellular and Molecular Physiology Yale Medical School New Haven CT USA
| | - Arashdeep Singh
- Department of Pharmacodynamics University of Florida Gainesville FL USA
- Center for Integrative Cardiovascular and Metabolic Disease University of Florida Gainesville FL USA
| | | | - Guillaume de Lartigue
- Department of Pharmacodynamics University of Florida Gainesville FL USA
- Center for Integrative Cardiovascular and Metabolic Disease University of Florida Gainesville FL USA
- The John B. Pierce Laboratory New Haven CT USA
- Department of Cellular and Molecular Physiology Yale Medical School New Haven CT USA
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11
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Duca FA, Waise TMZ, Peppler WT, Lam TKT. The metabolic impact of small intestinal nutrient sensing. Nat Commun 2021; 12:903. [PMID: 33568676 PMCID: PMC7876101 DOI: 10.1038/s41467-021-21235-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 01/19/2021] [Indexed: 12/12/2022] Open
Abstract
The gastrointestinal tract maintains energy and glucose homeostasis, in part through nutrient-sensing and subsequent signaling to the brain and other tissues. In this review, we highlight the role of small intestinal nutrient-sensing in metabolic homeostasis, and link high-fat feeding, obesity, and diabetes with perturbations in these gut-brain signaling pathways. We identify how lipids, carbohydrates, and proteins, initiate gut peptide release from the enteroendocrine cells through small intestinal sensing pathways, and how these peptides regulate food intake, glucose tolerance, and hepatic glucose production. Lastly, we highlight how the gut microbiota impact small intestinal nutrient-sensing in normal physiology, and in disease, pharmacological and surgical settings. Emerging evidence indicates that the molecular mechanisms of small intestinal nutrient sensing in metabolic homeostasis have physiological and pathological impact as well as therapeutic potential in obesity and diabetes. The gastrointestinal tract participates in maintaining metabolic homeostasis in part through nutrient-sensing and subsequent gut-brain signalling. Here the authors review the role of small intestinal nutrient-sensing in regulation of energy intake and systemic glucose metabolism, and link high-fat diet, obesity and diabetes with perturbations in these pathways.
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Affiliation(s)
- Frank A Duca
- BIO5 Institute, University of Arizona, Tucson, AZ, USA. .,School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA.
| | - T M Zaved Waise
- Toronto General Hospital Research Institute, UHN, Toronto, Canada
| | - Willem T Peppler
- Toronto General Hospital Research Institute, UHN, Toronto, Canada
| | - Tony K T Lam
- Toronto General Hospital Research Institute, UHN, Toronto, Canada. .,Department of Physiology, University of Toronto, Toronto, Canada. .,Department of Medicine, University of Toronto, Toronto, Canada. .,Banting and Best Diabetes Centre, University of Toronto, Toronto, Canada.
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12
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A Chemogenetic Tool that Enables Functional Neural Circuit Analysis. Cell Rep 2020; 32:108139. [DOI: 10.1016/j.celrep.2020.108139] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/02/2020] [Accepted: 08/21/2020] [Indexed: 01/31/2023] Open
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13
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Wang YB, de Lartigue G, Page AJ. Dissecting the Role of Subtypes of Gastrointestinal Vagal Afferents. Front Physiol 2020; 11:643. [PMID: 32595525 PMCID: PMC7300233 DOI: 10.3389/fphys.2020.00643] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/20/2020] [Indexed: 12/22/2022] Open
Abstract
Gastrointestinal (GI) vagal afferents convey sensory signals from the GI tract to the brain. Numerous subtypes of GI vagal afferent have been identified but their individual roles in gut function and feeding regulation are unclear. In the past decade, technical approaches to selectively target vagal afferent subtypes and to assess their function has significantly progressed. This review examines the classification of GI vagal afferent subtypes and discusses the current available techniques to study vagal afferents. Investigating the distribution of GI vagal afferent subtypes and understanding how to access and modulate individual populations are essential to dissect their fundamental roles in the gut-brain axis.
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Affiliation(s)
- Yoko B Wang
- Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Guillaume de Lartigue
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, United States.,Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL, United States
| | - Amanda J Page
- Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
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Chen X, Wyler SC, Li L, Arnold AG, Wan R, Jia L, Landy MA, Lai HC, Xu P, Liu C. Comparative Transcriptomic Analyses of Developing Melanocortin Neurons Reveal New Regulators for the Anorexigenic Neuron Identity. J Neurosci 2020; 40:3165-3177. [PMID: 32213554 PMCID: PMC7159888 DOI: 10.1523/jneurosci.0155-20.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/28/2020] [Accepted: 03/09/2020] [Indexed: 02/07/2023] Open
Abstract
Despite their opposing actions on food intake, POMC and NPY/AgRP neurons in the arcuate nucleus of the hypothalamus (ARH) are derived from the same progenitors that give rise to ARH neurons. However, the mechanism whereby common neuronal precursors subsequently adopt either the anorexigenic (POMC) or the orexigenic (NPY/AgRP) identity remains elusive. We hypothesize that POMC and NPY/AgRP cell fates are specified and maintained by distinct intrinsic factors. In search of them, we profiled the transcriptomes of developing POMC and NPY/AgRP neurons in mice. Moreover, cell-type-specific transcriptomic analyses revealed transcription regulators that are selectively enriched in either population, but whose developmental functions are unknown in these neurons. Among them, we found the expression of the PR domain-containing factor 12 (Prdm12) was enriched in POMC neurons but absent in NPY/AgRP neurons. To study the role of Prdm12 in vivo, we developed and characterized a floxed Prdm12 allele. Selective ablation of Prdm12 in embryonic POMC neurons led to significantly reduced Pomc expression as well as early-onset obesity in mice of either sex that recapitulates symptoms of human POMC deficiency. Interestingly, however, specific deletion of Prdm12 in adult POMC neurons showed that it is no longer required for Pomc expression or energy balance. Collectively, these findings establish a critical role for Prdm12 in the anorexigenic neuron identity and suggest that it acts developmentally to program body weight homeostasis. Finally, the combination of cell-type-specific genomic and genetic analyses provides a means to dissect cellular and functional diversity in the hypothalamus whose neurodevelopment remains poorly studied.SIGNIFICANCE STATEMENT POMC and NPY/AgRP neurons are derived from the same hypothalamic progenitors but have opposing effects on food intake. We profiled the transcriptomes of genetically labeled POMC and NPY/AgRP neurons in the developing mouse hypothalamus to decipher the transcriptional codes behind the versus orexigenic neuron identity. Our analyses revealed 29 transcription regulators that are selectively enriched in one of the two populations. We generated new mouse genetic models to selective ablate one of POMC-neuron enriched transcription factors Prdm12 in developing and adult POMC neurons. Our studies establish a previously unrecognized role for Prdm12 in the anorexigenic neuron identity and suggest that it acts developmentally to program body weight homeostasis.
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Affiliation(s)
- Xiameng Chen
- Department of Internal Medicine, Hypothalamic Research Center, Dallas, Texas 75390
| | - Steven C Wyler
- Department of Internal Medicine, Hypothalamic Research Center, Dallas, Texas 75390
| | - Li Li
- Department of Internal Medicine, Hypothalamic Research Center, Dallas, Texas 75390
| | - Amanda G Arnold
- Department of Internal Medicine, Hypothalamic Research Center, Dallas, Texas 75390
| | - Rong Wan
- Department of Internal Medicine, Hypothalamic Research Center, Dallas, Texas 75390
| | - Lin Jia
- Department of Internal Medicine, Hypothalamic Research Center, Dallas, Texas 75390
| | - Mark A Landy
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Helen C Lai
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Pin Xu
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Chen Liu
- Department of Internal Medicine, Hypothalamic Research Center, Dallas, Texas 75390
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390
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15
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Gavini CK, Bonomo R, Mansuy-Aubert V. Neuronal LXR Regulates Neuregulin 1 Expression and Sciatic Nerve-Associated Cell Signaling in Western Diet-fed Rodents. Sci Rep 2020; 10:6396. [PMID: 32286429 PMCID: PMC7156713 DOI: 10.1038/s41598-020-63357-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/21/2020] [Indexed: 11/09/2022] Open
Abstract
Neuropathic pain caused by peripheral nerve injuries significantly affects sensory perception and quality of life. Accumulating evidence strongly link cholesterol with development and progression of Obesity and Diabetes associated-neuropathies. However, the exact mechanisms of how cholesterol/lipid metabolism in peripheral nervous system (PNS) contributes to the pathogenesis of neuropathy remains poorly understood. Dysregulation of LXR pathways have been identified in many neuropathic models. The cholesterol sensor, LXR α/β, expressed in sensory neurons are necessary for proper peripheral nerve function. Deletion of LXR α/β from sensory neurons lead to pain-like behaviors. In this study, we identified that LXR α/β expressed in sensory neurons regulates neuronal Neuregulin 1 (Nrg1), protein involved in cell-cell communication. Using in vivo cell-specific approaches, we observed that loss of LXR from sensory neurons altered genes in non-neuronal cells located in the sciatic nerve (potentially representing Schwann cells (SC)). Our data suggest that neuronal LXRs may regulate non-neuronal cell function via a Nrg1-dependent mechanism. The decrease in Nrg1 expression in DRG neurons of WD-fed mice may suggest an altered Nrg1-dependent neuron-SC communication in Obesity. The communication between neurons and non-neuronal cells such as SC could be a new biological pathway to study and understand the molecular and cellular mechanism underlying Obesity-associated neuropathy and PNS dysfunction.
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Affiliation(s)
- Chaitanya K Gavini
- Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, 60153, USA
| | - Raiza Bonomo
- Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, 60153, USA
| | - Virginie Mansuy-Aubert
- Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, 60153, USA.
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16
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ASK1 inhibits browning of white adipose tissue in obesity. Nat Commun 2020; 11:1642. [PMID: 32242025 PMCID: PMC7118089 DOI: 10.1038/s41467-020-15483-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 03/10/2020] [Indexed: 12/13/2022] Open
Abstract
Increasing energy expenditure via induction of adipose tissue browning has become an appealing strategy to treat obesity and associated metabolic complications. Herein, we identify adipocyte-expressed apoptosis signal-regulating kinase 1 (ASK1) as regulator of adipose tissue browning. High fat diet-fed adipocyte-specific ASK1 knockout mice reveal increased UCP1 protein levels in inguinal adipose tissue concomitant with elevated energy expenditure, reduced obesity and ameliorated glucose tolerance compared to control littermates. In addition, ASK1-depletion blunts LPS-mediated downregulation of isoproterenol-induced UCP1 in subcutaneous fat both in vitro and in vivo. Conversely, adipocyte-specific ASK1 overexpression in chow-fed mice attenuates cold-induced UCP1 protein levels in inguinal fat. Mechanistically, ASK1 phosphorylates interferon regulatory factor 3 (IRF3) resulting in reduced Ucp1 expression. Taken together, our studies unravel a role of ASK1 in mediating the inhibitory effect of caloric surplus or LPS-treatment on adipose tissue browning. Adipocyte ASK1 might be a pharmacological target to combat obesity and associated morbidities.
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17
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Elkholy SE, Elaidy SM, El-Sherbeeny NA, Toraih EA, El-Gawly HW. Neuroprotective effects of ranolazine versus pioglitazone in experimental diabetic neuropathy: Targeting Nav1.7 channels and PPAR-γ. Life Sci 2020; 250:117557. [PMID: 32184124 DOI: 10.1016/j.lfs.2020.117557] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 02/22/2020] [Accepted: 03/13/2020] [Indexed: 12/11/2022]
Abstract
Diabetic neuropathy (DN) is a common complication of diabetes mellitus (DM). Pathophysiology of DN includes inflammation and changes in expression and function of voltage-gated sodium channels (Nav) in peripheral nerves; and central reduction of Peroxisome Proliferator Activated Receptor-Gamma (PPAR-γ) expression. AIM This study explored the effect of ranolazine (RN) versus pioglitazone (PIO) in DN induced in rats. The role of sciatic interleukin (IL)-1β, tumor necrosis factor-alpha (TNF)-α, Nav1.7, and spinal PPAR-γ expressions were determined. MATERIALS AND METHODS For induction of Type-2 DM, 40 high fat diet-fed rats were challenged by a single dose of intraperitoneal streptozotocin (30 mg/kg). One week later, oral PIO (10 mg/kg; once daily) or RN (20, 50 and 100 mg/kg; twice daily) were administered for six weeks. Weekly body weight and fasting blood sugar (FBS) were measured. Rats were tested for thermal hyperalgesia and mechanical allodynia. At the end of the experiment, sciatic nerves homogenates were examined for TNF-α and IL-1B levels, and Nav1.7 channel expression. Segments of spinal cords were investigated for the PPAR-γ gene expression. Evaluation of histopathology of sciatic nerves and spinal cords were done. KEY FINDINGS In diabetic rats, PIO and RN individually improved evoked-pain behaviors, reduced sciatic TNF-α and 1L-1B levels; downregulated expressional levels of Nav1.7 channels; and increased the spinal PPAR-γ gene expression. RN in the dose of 100 mg/kg/day showed the most advantageous effects. SIGNIFICANCE RN has neuroprotective effects in Type-2 diabetes-induced DN. Further studies of combined RN-PIO treatment are recommended, especially in diabetic patients with cardiovascular co-morbidity.
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Affiliation(s)
- Shereen E Elkholy
- Department of Clinical Pharmacology, Faculty of Medicine, Port-Said University, Port-Said, Egypt
| | - Samah M Elaidy
- Department of Clinical Pharmacology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Nagla A El-Sherbeeny
- Department of Clinical Pharmacology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.
| | - Eman A Toraih
- Department of Surgery, Tulane University, School of Medicine, New Orleans, LA, USA; Genetics Unit, Department of Histology and Cell Biology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt; Center of Excellence of Molecular and Cellular Medicine, Suez Canal University, Ismailia, Egypt
| | - Hoda W El-Gawly
- Department of Clinical Pharmacology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
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18
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Nagasaka R, Nakachi H, Onodera Y, Ishikawa Y, Ohshima T. Leptin promotes the fat preference associated with low-temperature acclimation in mice. Biosci Biotechnol Biochem 2020; 84:1250-1258. [PMID: 32093588 DOI: 10.1080/09168451.2020.1732186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Although fluctuations in energy metabolism are known to influence intake as well as nutrient selection, there are no definitive reports on how food preferences change with changes in habitat temperature. We investigated the effects of habitat temperature on appetite and food preference and elucidated the underlying mechanism by conducting a feeding experiment and a leptin administration test on mice reared at low temperatures. Our results showed that the increased food intake and HFD preference observed in the 10°C group were induced by decrease in plasma leptin concentration. Then, a leptin administration experiment was conducted to clarify the relationship between leptin and food preference with low-temperature acclimation. The control group reared in 10°C significantly preferred the HFD, but the leptin-administered group did not. These results show that the peripheral system appetite-regulating hormone leptin not only acts to suppress appetite but also might inhibit preference for lipids in low-temperature acclimation.
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Affiliation(s)
- Reiko Nagasaka
- Department of Food Science and Technology, Graduate School of Marine Science and Technology, Tokyo, Japan
| | - Hazuki Nakachi
- Department of Food Science and Technology, Graduate School of Marine Science and Technology, Tokyo, Japan
| | - Yuka Onodera
- Department of Food Science and Technology, Graduate School of Marine Science and Technology, Tokyo, Japan
| | - Yuki Ishikawa
- Department of Food Science and Technology, Graduate School of Marine Science and Technology, Tokyo, Japan
| | - Toshiaki Ohshima
- Department of Food Science and Technology, Graduate School of Marine Science and Technology, Tokyo, Japan
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19
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Gavini CK, Bookout AL, Bonomo R, Gautron L, Lee S, Mansuy-Aubert V. Liver X Receptors Protect Dorsal Root Ganglia from Obesity-Induced Endoplasmic Reticulum Stress and Mechanical Allodynia. Cell Rep 2019; 25:271-277.e4. [PMID: 30304667 PMCID: PMC7732131 DOI: 10.1016/j.celrep.2018.09.046] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 06/15/2018] [Accepted: 09/12/2018] [Indexed: 01/22/2023] Open
Abstract
Obesity is associated with many complications, including type 2 diabetes and painful neuropathy. There is no cure or prevention for obesity-induced pain, and the neurobiology underlying the onset of the disease is still obscure. In this study, we observe that western diet (WD)-fed mice developed early allodynia with an increase of ER stress markers in the sensory neurons of the dorsal root ganglia (DRG). Using cell-specific approaches, we demonstrate that neuronal liver X receptor (LXR) activation delays ER stress and allodynia in WD-fed mice. Our findings suggest that lipid-binding nuclear receptors expressed in the sensory neurons of the DRG play a role in the onset of obesity-induced hypersensitivity. The LXR and lipid-sensor pathways represent a research avenue to identify targets to prevent debilitating complications affecting the peripheral nerve system in obesity. The mechanism underlying obesityinduced pain is explored by Gavini et al. using cell-specific models. Their analysis reveals that in sensory neurons of the dorsal root ganglia, LXR activation delays western diet-induced ER stress and allodynia. These findings suggest that LXRs in sensory neurons are involved in nociception induced by western diet nutrition.
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Affiliation(s)
- Chaitanya K Gavini
- Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA
| | - Angie L Bookout
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Raiza Bonomo
- Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA
| | - Laurent Gautron
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Syann Lee
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Virginie Mansuy-Aubert
- Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA.
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20
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Sandoval DA. Mechanisms for the metabolic success of bariatric surgery. J Neuroendocrinol 2019; 31:e12708. [PMID: 30882956 PMCID: PMC9205614 DOI: 10.1111/jne.12708] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/11/2019] [Accepted: 03/13/2019] [Indexed: 12/14/2022]
Abstract
To date, bariatric surgery remains the most effective strategy for the treatment of obesity and its comorbidities. However, given the enormity of the obesity epidemic, and sometimes variable results, it is not a feasible strategy for the treatment of all obese patients. A simple PubMed search for 'bariatric surgery' reveals over 28 000 papers that have been published since the 1940s when the first bariatric surgeries were performed. However, there is still an incomplete understanding of the mechanisms for the weight loss and metabolic success of surgery. An understanding of the mechanisms is important because it may lead to greater understanding of the pathophysiology of obesity and thus surgery-alternative strategies for the treatment of all obese patients. In this review, the potential mechanisms that underlie the success of surgery are discussed, with a focus on the potential endocrine, neural and other circulatory factors (eg, bile acids) that have been proposed to play a role.
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21
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Wang R, Lu Y, Cicha MZ, Singh MV, Benson CJ, Madden CJ, Chapleau MW, Abboud FM. TMEM16B determines cholecystokinin sensitivity of intestinal vagal afferents of nodose neurons. JCI Insight 2019; 4:122058. [PMID: 30843875 DOI: 10.1172/jci.insight.122058] [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: 05/07/2018] [Accepted: 01/17/2019] [Indexed: 12/11/2022] Open
Abstract
The satiety effects and metabolic actions of cholecystokinin (CCK) have been recognized as potential therapeutic targets in obesity for decades. We identified a potentially novel Ca2+-activated chloride (Cl-) current (CaCC) that is induced by CCK in intestinal vagal afferents of nodose neurons. The CaCC subunit Anoctamin 2 (Ano2/TMEM16B) is the dominant contributor to this current. Its expression is reduced, as is CCK current activity in obese mice on a high-fat diet (HFD). Reduced expression of TMEM16B in the heterozygote KO of the channel in sensory neurons results in an obese phenotype with a loss of CCK sensitivity in intestinal nodose neurons, a loss of CCK-induced satiety, and metabolic changes, including decreased energy expenditure. The effect on energy expenditure is further supported by evidence in rats showing that CCK enhances sympathetic nerve activity and thermogenesis in brown adipose tissue, and these effects are abrogated by a HFD and vagotomy. Our findings reveal that Ano2/TMEM16B is a Ca2+-activated chloride channel in vagal afferents of nodose neurons and a major determinant of CCK-induced satiety, body weight control, and energy expenditure, making it a potential therapeutic target in obesity.
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Affiliation(s)
- Runping Wang
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and
| | - Yongjun Lu
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and
| | - Michael Z Cicha
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and
| | - Madhu V Singh
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and
| | - Christopher J Benson
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and.,Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA.,Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Christopher J Madden
- Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon, USA
| | - Mark W Chapleau
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and.,Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA.,Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - François M Abboud
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and.,Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA
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22
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Fedele S, Arnold M, Krieger JP, Wolfstädter B, Meyer U, Langhans W, Mansouri A. Oleoylethanolamide-induced anorexia in rats is associated with locomotor impairment. Physiol Rep 2019; 6. [PMID: 29388342 PMCID: PMC5817840 DOI: 10.14814/phy2.13517] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 11/01/2017] [Indexed: 11/24/2022] Open
Abstract
The endogenous peroxisome proliferator‐activated receptor alpha (PPAR‐α) agonist Oleoylethanolamide (OEA) inhibits eating in rodents, mainly by delaying the onset of meals. The underlying mechanisms of OEA‐induced anorexia, however, remain unclear. Animals treated with high OEA doses were shown to display signs of discomfort and impaired locomotion. Therefore, we first examined whether the impaired locomotion may contribute to OEA's anorectic effect. Second, it is controversial whether abdominal vagal afferents are necessary for OEA's anorectic effect. Thus, we explored alternative peripheral neural pathways mediating IP OEA's anorectic effect by performing a celiac‐superior mesenteric ganglionectomy (CGX) or a subdiaphragmatic vagal deafferentation (SDA) alone or in combination. Exogenously administered OEA at a commonly used dose (10 mg/kg BW, IP) concurrently reduced food intake and compromised locomotor activity. Attempts to dissociate both phenomena using the dopamine D2/D3 receptor agonist Quinpirole (1 mg/kg BW, SC) failed because Quinpirole antagonized both, OEA‐induced locomotor impairment and delay in eating onset. CGX attenuated the prolongation of the latency to eat by IP OEA, but neither SDA nor CGX prevented IP OEA‐induced locomotor impairment. Our results indicate that IP OEA's anorectic effect may be secondary to impaired locomotion rather than due to physiological satiety. They further confirm that vagal afferents do not mediate exogenous OEA's anorectic effects, but suggest a role for spinal afferents in addition to an alternative, nonneuronal signaling route.
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Affiliation(s)
- Shahana Fedele
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | - Myrtha Arnold
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | | | - Bernd Wolfstädter
- Laboratorium für Organische Chemie, ETH Zurich, Zürich, Switzerland.,Laboratory of Translational Nutrition Biology, ETH Zurich, Schwerzenbach, Switzerland
| | - Urs Meyer
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Abdelhak Mansouri
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
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23
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Larsson S, Voss U. Neuroprotective effects of vitamin D on high fat diet- and palmitic acid-induced enteric neuronal loss in mice. BMC Gastroenterol 2018; 18:175. [PMID: 30463517 PMCID: PMC6249721 DOI: 10.1186/s12876-018-0905-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 11/08/2018] [Indexed: 01/26/2023] Open
Abstract
Background The role of vitamin D in obesity and diabetes is debated. Obese and/or diabetic patients have elevated levels of free fatty acids, increased susceptibility to gastrointestinal symptoms and are suggested to have altered vitamin D balance. The enteric nervous system is pivotal in regulating gastrointestinal activity and high fat diet (HFD) has been shown to cause loss of enteric neurons in ileum and colon. This study investigates the effect of vitamin D on HFD- and palmitic acid-induced enteric neuronal loss in vivo and in vitro. Methods Mice were fed either a normal diet (ND) or HFD supplemented with varying levels of vitamin D (from 0x to 20x normal vitamin D level) for 19 weeks. Ileum and colon were analyzed for neuronal numbers and remodeling. Primary cultures of myenteric neurons from mouse small intestine were treated with palmitic acid (4x10-4M) and/or 1α,25-hydroxy-vitamin D3 (VD, 10-11- 10-7M) with or without modulators of lipid metabolism and VD pathways. Cultures were analyzed by immunocyto- and histochemical methods. Results Vitamin D supplementation had no effect on enteric neuronal survival in the ND group. HFD caused substantial loss of myenteric neurons in ileum and colon. Vitamin D supplementation between 0-2x normal had no effect on HFD-induced neuronal loss. Supplementation with 20x normal, prevented the HFD-induced neuronal loss. In vitro supplementation of VD prevented the palmitic acid-induced neuronal loss. The VD receptor (VDR) was not identified in enteric neurons. Enteric glia expressed the alternative VD receptor, protein disulphide isomerase family A member 3 (PDIA3), but PDIA3 was not found to mediate the VD response in vitro. Inhibition of peroxisome proliferator-activated receptor gamma (PPARγ) and immune neutralization of isocitrate lyase prevented the VD mediated neuroprotection to palmitic acid exposure. Conclusions Results show that VD protect enteric neurons against HFD and palmitic acid induced neuronal loss. The mechanism behind is suggested to be through activation of PPARγ leading to improved neuronal peroxisome function and metabolism of neuronal lipid intermediates.
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Affiliation(s)
- Sara Larsson
- Unit of Molecular Endocrinology, Department of Experimental Medical Science, Lund University, Sölvegatan 19, BMC C11, 22184, Lund, Sweden
| | - Ulrikke Voss
- Unit of Neurogastroenterology, Department of Experimental Medical Science, Lund University, Sölvegatan 19, BMC B11, 22184, Lund, Sweden.
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24
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Caillon A, Duszka K, Wahli W, Rohner-Jeanrenaud F, Altirriba J. The OEA effect on food intake is independent from the presence of PPARα in the intestine and the nodose ganglion, while the impact of OEA on energy expenditure requires the presence of PPARα in mice. Metabolism 2018; 87:13-17. [PMID: 29936173 DOI: 10.1016/j.metabol.2018.06.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 06/15/2018] [Accepted: 06/18/2018] [Indexed: 01/12/2023]
Abstract
BACKGROUND Oleoylethanolamide (OEA) is an endocannabinoid that controls food intake, energy expenditure and locomotor activity. Its anorexigenic effect appears to be mediated by PPARα, but the tissue where the presence of this receptor is required for OEA to inhibit feeding is unknown as yet. Previous studies point to a possible role of proximal enterocytes and neurons of the nodose ganglion. MATERIALS AND METHODS Acute intraperitoneal OEA effects on food intake, energy expenditure, respiratory exchange ratio (RER) and locomotor activity were studied in control mice (PPARα-loxP) and intestinal (Villin-Cre;PPARα-loxP) or nodose ganglion (Phox2B-Cre;PPARα-loxP) specific PPARα knockout mice placed in calorimetric cages. RESULTS OEA administration to both intestinal and nodose ganglion PPARα knockout mice decreased food intake, RER (leading to increased lipid oxidation) and locomotor activity as in control mice. However, while OEA injection acutely decreased energy expenditure in controls, this effect was not observed in mice devoid of PPARα in the intestine. CONCLUSION These results indicate that the OEA effect on food intake is independent from the presence of PPARα in the intestine and the nodose ganglion, while the impact of OEA on energy expenditure requires the presence of PPARα in the intestine.
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Affiliation(s)
- Aurélie Caillon
- Laboratory of Metabolism, Department of Medicine Specialties, Faculty of Medicine, University of Geneva, Geneva, Switzerland; Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Kalina Duszka
- Center for Integrative Genomics, University of Lausanne, Le Génopode, 1015 Lausanne, Switzerland
| | - Walter Wahli
- Center for Integrative Genomics, University of Lausanne, Le Génopode, 1015 Lausanne, Switzerland; Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 11 Mandalay Road, 308232, Singapore
| | - Françoise Rohner-Jeanrenaud
- Laboratory of Metabolism, Department of Medicine Specialties, Faculty of Medicine, University of Geneva, Geneva, Switzerland; Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Jordi Altirriba
- Laboratory of Metabolism, Department of Medicine Specialties, Faculty of Medicine, University of Geneva, Geneva, Switzerland; Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
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25
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de Lartigue G, Xu C. Mechanisms of vagal plasticity influencing feeding behavior. Brain Res 2018; 1693:146-150. [PMID: 29903616 PMCID: PMC6996925 DOI: 10.1016/j.brainres.2018.03.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/21/2018] [Accepted: 03/26/2018] [Indexed: 12/18/2022]
Abstract
Sensory neurons of the vagus nerve receive many different peripheral signals that can change rapidly and frequently throughout the day. The ability of these neurons to convey the vast array of nuanced information to the brain requires neuronal adaptability. In this review we discuss evidence for neural plasticity in vagal afferent neurons as a mechanism for conveying nuanced information to the brain important for the control of feeding behavior. We provide evidence that synaptic plasticity, changes in membrane conductance, and neuropeptide specification are mechanisms that allow flexibility in response to metabolic cues that can be disrupted by chronic intake of energy dense diets.
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Affiliation(s)
| | - Chelsea Xu
- Department Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
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26
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Okada T, Waise TZ, Toshinai K, Mita Y, Sakoda H, Nakazato M. Analysis of peripheral ghrelin signaling via the vagus nerve in ghrelin receptor–restored GHSR-null mice. Neurosci Lett 2018; 681:50-55. [DOI: 10.1016/j.neulet.2018.05.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/10/2018] [Accepted: 05/22/2018] [Indexed: 12/25/2022]
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27
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Krieger JP, Santos da Conceição EP, Sanchez-Watts G, Arnold M, Pettersen KG, Mohammed M, Modica S, Lossel P, Morrison SF, Madden CJ, Watts AG, Langhans W, Lee SJ. Glucagon-like peptide-1 regulates brown adipose tissue thermogenesis via the gut-brain axis in rats. Am J Physiol Regul Integr Comp Physiol 2018; 315:R708-R720. [PMID: 29847161 DOI: 10.1152/ajpregu.00068.2018] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Endogenous intestinal glucagon-like peptide-1 (GLP-1) controls satiation and glucose metabolism via vagal afferent neurons (VANs). Recently, VANs have received increasing attention for their role in brown adipose tissue (BAT) thermogenesis. It is, however, unclear whether VAN GLP-1 receptor (GLP-1R) signaling affects BAT thermogenesis and energy expenditure (EE) and whether this VAN mechanism contributes to energy balance. First, we tested the effect of the GLP-1R agonist exendin-4 (Ex4, 0.3 μg/kg ip) on EE and BAT thermogenesis and whether these effects require VAN GLP-1R signaling using a rat model with a selective Glp1r knockdown (kd) in VANs. Second, we examined the role of VAN GLP-1R in energy balance during chronic high-fat diet (HFD) feeding in VAN Glp1r kd rats. Finally, we used viral transsynaptic tracers to identify the possible neuronal substrates of such a gut-BAT interaction. VAN Glp1r kd attenuated the acute suppressive effects of Ex4 on EE and BAT thermogenesis. Consistent with this finding, the VAN Glp1r kd increased EE and BAT activity, diminished body weight gain, and improved insulin sensitivity compared with HFD-fed controls. Anterograde transsynaptic viral tracing of VANs infected major hypothalamic and hindbrain areas involved in BAT sympathetic regulation. Moreover, retrograde tracing from BAT combined with laser capture microdissection revealed that a population of VANs expressing Glp1r is synaptically connected to the BAT. Our findings reveal a novel role of VAN GLP-1R signaling in the regulation of EE and BAT thermogenesis and imply that through this gut-brain-BAT connection, intestinal GLP-1 plays a role in HFD-induced metabolic syndrome.
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Affiliation(s)
- Jean-Philippe Krieger
- Physiology and Behavior Laboratory, Eidgenössische Technische Hochschule Zürich, Schwerzenbach, Switzerland
| | | | - Graciela Sanchez-Watts
- Department of Biological Sciences, University of Southern California , Los Angeles, California
| | - Myrtha Arnold
- Physiology and Behavior Laboratory, Eidgenössische Technische Hochschule Zürich, Schwerzenbach, Switzerland
| | - Klaus G Pettersen
- Physiology and Behavior Laboratory, Eidgenössische Technische Hochschule Zürich, Schwerzenbach, Switzerland
| | - Mazher Mohammed
- Department of Neurological Surgery, Oregon Health and Science University , Portland, Oregon
| | - Salvatore Modica
- Translational Nutrition Biology Laboratory, Eidgenössische Technische Hochschule Zürich, Schwerzenbach, Switzerland
| | - Pius Lossel
- Physiology and Behavior Laboratory, Eidgenössische Technische Hochschule Zürich, Schwerzenbach, Switzerland
| | - Shaun F Morrison
- Department of Neurological Surgery, Oregon Health and Science University , Portland, Oregon
| | - Christopher J Madden
- Department of Neurological Surgery, Oregon Health and Science University , Portland, Oregon
| | - Alan G Watts
- Department of Biological Sciences, University of Southern California , Los Angeles, California
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, Eidgenössische Technische Hochschule Zürich, Schwerzenbach, Switzerland
| | - Shin J Lee
- Physiology and Behavior Laboratory, Eidgenössische Technische Hochschule Zürich, Schwerzenbach, Switzerland
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Yu J, Koenig RJ. Thyroid-Specific PPARγ Deletion Is Benign in the Mouse. Endocrinology 2018; 159:1463-1468. [PMID: 29420754 PMCID: PMC5839734 DOI: 10.1210/en.2017-03163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 01/30/2018] [Indexed: 12/16/2022]
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is widely expressed at low levels and regulates many physiological processes. In mice and humans, there is evidence that PPARγ can function as a tumor suppressor. A PAX8-PPARγ fusion protein (PPFP) is oncogenic in a subset of thyroid cancers, suggesting that inhibition of endogenous PPARγ function by the fusion protein could contribute to thyroid oncogenesis. However, the function of PPARγ within thyrocytes has never been directly tested. Therefore, we have created a thyroid-specific genetic knockout of murine Pparg and have studied thyroid biology in these mice. Thyroid size and histology, the expression of thyroid-specific genes, and serum T4 levels all are unaffected by loss of thyroidal PPARγ expression. PPFP thyroid cancers have increased activation of AKT, and mice with thyroid-specific expression of PPFP combined with thyroid-specific loss of PTEN (a negative regulator of AKT) develop thyroid cancer. Therefore we created mice with combined thyroid-specific deletions of Pparg and Pten to test if there is oncogenic synergy between these deletions. Pten deletion alone results in benign thyroid hyperplasia, and this is unchanged when combined with deletion of Pparg. We conclude that, at least in the contexts studied, thyrocyte PPARγ does not play a significant role in the development or function of the thyroid and does not function as a tumor suppressor.
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Affiliation(s)
- Jingcheng Yu
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, Michigan 48109
| | - Ronald J. Koenig
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, Michigan 48109
- Correspondence: Ronald J. Koenig, MD, PhD, 5560 MSRB-2, SPC 5678, 1150 West Medical Center Drive, Ann Arbor, Michigan 48109. E-mail:
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29
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Kim KS, Seeley RJ, Sandoval DA. Signalling from the periphery to the brain that regulates energy homeostasis. Nat Rev Neurosci 2018; 19:185-196. [DOI: 10.1038/nrn.2018.8] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
Stress affects core body temperature (Tc). Many kinds of stress induce transient, monophasic hyperthermia, which diminishes gradually if the stressor is terminated. Stronger stressors produce a longer-lasting effect. Repeated/chronic stress induces anticipatory hyperthermia, reduces diurnal changes in Tc, or slightly increases Tc throughout the day. Animals that are exposed to chronic stress or a cold environment exhibit an enhanced hyperthermic response to a novel stress. These changes persist for several days after cessation of stress exposure. In contrast, long-lasting inescapable stress sometimes induces hypothermia. In healthy humans, psychologic stress induces slight increases in Tc, which are within the normal range of Tc or just above it. Some individuals, however, develop extremely high Tc (up to 41°C) when they are exposed to emotional events or show persistent low-grade high Tc (37-38°C) during or after chronic stress situations. In addition to the nature of the stressor itself, such stress-induced thermal responses are modulated by sex, age, ambient temperature, cage mates, past stressful experiences and cold exposure, and coping. Stress-induced hyperthermia is driven by mechanisms distinct from infectious fever, which requires inflammatory mediators. However, both stress and infection activate the dorsomedial hypothalamus-rostral medullary raphe region-sympathetic nerve axis to increase Tc.
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Affiliation(s)
- Takakazu Oka
- Department of Psychosomatic Medicine, International University of Health and Welfare Hospital, Tochigi-ken, Japan.
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31
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Sierra S, Luquin N, Navarro-Otano J. The endocannabinoid system in cardiovascular function: novel insights and clinical implications. Clin Auton Res 2017; 28:35-52. [PMID: 29222605 DOI: 10.1007/s10286-017-0488-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 11/28/2017] [Indexed: 12/18/2022]
Abstract
RATIONALE Cardiovascular disease is now recognized as the number one cause of death in the world, and the size of the population at risk continues to increase rapidly. The dysregulation of the endocannabinoid (eCB) system plays a central role in a wide variety of conditions including cardiovascular disorders. Cannabinoid receptors, their endogenous ligands, as well as enzymes conferring their synthesis and degradation, exhibit overlapping distributions in the cardiovascular system. Furthermore, the pharmacological manipulation of the eCB system has effects on blood pressure, cardiac contractility, and endothelial vasomotor control. Growing evidence from animal studies supports the significance of the eCB system in cardiovascular disorders. OBJECTIVE To summarize the literature surrounding the eCB system in cardiovascular function and disease and the new compounds that may potentially extend the range of available interventions. RESULTS Drugs targeting CB1R, CB2R, TRPV1 and PPARs are proven effective in animal models mimicking cardiovascular disorders such as hypertension, atherosclerosis and myocardial infarction. Despite the setback of two clinical trials that exhibited unexpected harmful side-effects, preclinical studies are accelerating the development of more selective drugs with promising results devoid of adverse effects. CONCLUSION Over the last years, increasing evidence from basic and clinical research supports the role of the eCB system in cardiovascular function. Whereas new discoveries are paving the way for the identification of novel drugs and therapeutic targets, the close cooperation of researchers, clinicians and pharmaceutical companies is needed to achieve successful outcomes.
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Affiliation(s)
- Salvador Sierra
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA. .,Department of Physiology and Biophysics, Molecular Medicine Research Building, Virginia Commonwealth University, 1220 East Broad Street, Richmond, VA, 23298, USA.
| | - Natasha Luquin
- Department of Medical Genomics, Royal Prince Alfred Hospital, Sydney, Australia
| | - Judith Navarro-Otano
- Neurology Service, Electromyography, Motor Control and Neuropathic Pain Unit, Hospital Clínic de Barcelona, University of Barcelona, Barcelona, Spain
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32
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Wiedmann NM, Stefanidis A, Oldfield BJ. Characterization of the central neural projections to brown, white, and beige adipose tissue. FASEB J 2017; 31:4879-4890. [DOI: 10.1096/fj.201700433r] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 07/05/2017] [Indexed: 12/13/2022]
Affiliation(s)
| | - Aneta Stefanidis
- Department of PhysiologyMonash UniversityClaytonVictoriaAustralia
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33
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Xiang H, Zhong ZX, Peng YD, Jiang SW. The Emerging Role of Zfp217 in Adipogenesis. Int J Mol Sci 2017; 18:ijms18071367. [PMID: 28653987 PMCID: PMC5535860 DOI: 10.3390/ijms18071367] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 06/12/2017] [Accepted: 06/21/2017] [Indexed: 12/16/2022] Open
Abstract
Zinc finger protein 217 (Zfp217), a member of the krüppel-type zinc finger protein family, plays diverse roles in cell differentiation and development of mammals. Despite extensive research on the functions of Zfp217 in cancer, pluripotency and reprogramming, its physiological roles in adipogenesis remain unknown. Our previous RNA sequencing data suggest the involvement of Zfp217 in adipogenesis. In this study, the potential function of Zfp217 in adipogenesis was investigated through bioinformatics analysis and a series of experiments. The expression of Zfp217 was found to be gradually upregulated during the adipogenic differentiation in C3H10T1/2 cells, which was consistent with that of the adipogenic marker gene Pparg2. Furthermore, there was a positive, significant relationship between Zfp217 expression and adipocyte differentiation. It was also observed that Zfp217 could not only trigger proliferative defect in C3H10T1/2 cells, but also interact with Ezh2 and suppress the downstream target genes of Ezh2. Besides, three microRNAs (miR-503-5p, miR-135a-5p and miR-19a-3p) which target Zfp217 were found to suppress the process of adipogenesis. This is the first report showing that Zfp217 has the capacity to regulate adipogenesis.
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Affiliation(s)
- Hong Xiang
- Key Laboratory of Swine Genetics and Breeding of Agricultural Ministry, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Zhu-Xia Zhong
- Key Laboratory of Swine Genetics and Breeding of Agricultural Ministry, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Yong-Dong Peng
- Key Laboratory of Swine Genetics and Breeding of Agricultural Ministry, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
- Hebei Key Laboratory of Veterinary Preventive Medicine, College of Animal Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao 066004, China.
| | - Si-Wen Jiang
- Key Laboratory of Swine Genetics and Breeding of Agricultural Ministry, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.
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34
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Burke LK, Darwish T, Cavanaugh AR, Virtue S, Roth E, Morro J, Liu SM, Xia J, Dalley JW, Burling K, Chua S, Vidal-Puig T, Schwartz GJ, Blouet C. mTORC1 in AGRP neurons integrates exteroceptive and interoceptive food-related cues in the modulation of adaptive energy expenditure in mice. eLife 2017; 6. [PMID: 28532548 PMCID: PMC5441868 DOI: 10.7554/elife.22848] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 04/18/2017] [Indexed: 01/19/2023] Open
Abstract
Energy dissipation through interscapular brown adipose tissue (iBAT) thermogenesis is an important contributor to adaptive energy expenditure. However, it remains unresolved how acute and chronic changes in energy availability are detected by the brain to adjust iBAT activity and maintain energy homeostasis. Here, we provide evidence that AGRP inhibitory tone to iBAT represents an energy-sparing circuit that integrates environmental food cues and internal signals of energy availability. We establish a role for the nutrient-sensing mTORC1 signaling pathway within AGRP neurons in the detection of environmental food cues and internal signals of energy availability, and in the bi-directional control of iBAT thermogenesis during nutrient deficiency and excess. Collectively, our findings provide insights into how mTORC1 signaling within AGRP neurons surveys energy availability to engage iBAT thermogenesis, and identify AGRP neurons as a neuronal substrate for the coordination of energy intake and adaptive expenditure under varying physiological and environmental contexts. DOI:http://dx.doi.org/10.7554/eLife.22848.001 Losing weight through dieting can be difficult. Weight loss strategies often prove ineffective because the body works like a thermostat and couples what we eat to the number of calories we burn. When we eat less, our bodies compensate and burn fewer calories, which makes losing weight harder. The brain is the master regulator of this caloric thermostat, but it is not clear how it adjusts our energy expenditure to account for how much we have eaten. A structure deep within the brain called the hypothalamus, which helps regulate appetite, is thought to be involved in the caloric thermostat. Activating a group of neurons within the hypothalamus called the agouti-related neuropeptide (AGRP) neurons causes animals to consume large quantities of food. By contrast, inhibiting AGRP neurons causes animals to stop eating almost entirely. Burke et al. studied AGRP neurons in mice. The experiments show that artificially activating the neurons in mice that don’t have access to food increases the animals’ activity levels but reduces the rate at which they burn calories, which helps the mice to maintain their existing weight. Allowing the mice to eat, or even just to see and smell food, switches off this effect and returns energy expenditure to normal. Finally, exposing mice to a high-fat diet for several days inhibits their AGRP neurons, and causes the animals to burn calories at a faster rate. By using up excess calories, this change also helps the animals maintain their existing body weight. The findings of Burke et al. show that AGRP neurons are a key component of the caloric thermostat. By adjusting the rate at which the body burns calories, AGRP neurons can compensate for any changes in food intake and so limit changes in body weight. This work opens up the possibility of developing therapies that disconnect energy expenditure from energy intake to help maintain long-term weight loss. DOI:http://dx.doi.org/10.7554/eLife.22848.002
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Affiliation(s)
- Luke K Burke
- MRC Metabolic Diseases Unit, Metabolic Research Laboratories, University of Cambridge, Cambridge, United Kingdom.,WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Tamana Darwish
- MRC Metabolic Diseases Unit, Metabolic Research Laboratories, University of Cambridge, Cambridge, United Kingdom.,WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Althea R Cavanaugh
- Departments of Medicine and Neuroscience, The Albert Einstein College of Medicine, New York, United States
| | - Sam Virtue
- MRC Metabolic Diseases Unit, Metabolic Research Laboratories, University of Cambridge, Cambridge, United Kingdom.,WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Emma Roth
- MRC Metabolic Diseases Unit, Metabolic Research Laboratories, University of Cambridge, Cambridge, United Kingdom.,WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Joanna Morro
- MRC Metabolic Diseases Unit, Metabolic Research Laboratories, University of Cambridge, Cambridge, United Kingdom.,WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Shun-Mei Liu
- Departments of Medicine and Neuroscience, The Albert Einstein College of Medicine, New York, United States
| | - Jing Xia
- Department of Psychology, Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom
| | - Jeffrey W Dalley
- Department of Psychology, Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom.,Department of Psychiatry, Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom
| | - Keith Burling
- MRC Metabolic Diseases Unit, Metabolic Research Laboratories, University of Cambridge, Cambridge, United Kingdom.,WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Streamson Chua
- Departments of Medicine and Neuroscience, The Albert Einstein College of Medicine, New York, United States
| | - Toni Vidal-Puig
- MRC Metabolic Diseases Unit, Metabolic Research Laboratories, University of Cambridge, Cambridge, United Kingdom.,WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Gary J Schwartz
- Departments of Medicine and Neuroscience, The Albert Einstein College of Medicine, New York, United States
| | - Clémence Blouet
- MRC Metabolic Diseases Unit, Metabolic Research Laboratories, University of Cambridge, Cambridge, United Kingdom.,WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
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35
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Sen T, Cawthon CR, Ihde BT, Hajnal A, DiLorenzo PM, de La Serre CB, Czaja K. Diet-driven microbiota dysbiosis is associated with vagal remodeling and obesity. Physiol Behav 2017; 173:305-317. [PMID: 28249783 DOI: 10.1016/j.physbeh.2017.02.027] [Citation(s) in RCA: 170] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 01/27/2017] [Accepted: 02/22/2017] [Indexed: 02/06/2023]
Abstract
Obesity is one of the major health issues in the United States. Consumption of diets rich in energy, notably from fats and sugars (high-fat/high-sugar diet: HF/HSD) is linked to the development of obesity and a popular dietary approach for weight loss is to reduce fat intake. Obesity research traditionally uses low and high fat diets and there has been limited investigation of the potential detrimental effects of a low-fat/high-sugar diet (LF/HSD) on body fat accumulation and health. Therefore, in the present study, we investigated the effects of HF/HSD and LF/HSD on microbiota composition, gut inflammation, gut-brain vagal communication and body fat accumulation. Specifically, we tested the hypothesis that LF/HSD changes the gut microbiota, induces gut inflammation and alters vagal gut-brain communication, associated with increased body fat accumulation. Sprague-Dawley rats were fed an HF/HSD, LF/HSD or control low-fat/low-sugar diet (LF/LSD) for 4weeks. Body weight, caloric intake, and body composition were monitored daily and fecal samples were collected at baseline, 1, 6 and 27days after the dietary switch. After four weeks, blood and tissues (gut, brain, liver and nodose ganglia) were sampled. Both HF/HSD and LF/HSD-fed rats displayed significant increases in body weight and body fat compared to LF/LSD-fed rats. 16S rRNA sequencing showed that both HF/HSD and LF/HSD-fed animals exhibited gut microbiota dysbiosis characterized by an overall decrease in bacterial diversity and an increase in Firmicutes/Bacteriodetes ratio. Dysbiosis was typified by a bloom in Clostridia and Bacilli and a marked decrease in Lactobacillus spp. LF/HSD-fed animals showed a specific increase in Sutterella and Bilophila, both Proteobacteria, abundances of which have been associated with liver damage. Expression of pro-inflammatory cytokines, such as IL-6, IL-1β and TNFα, was upregulated in the cecum while levels of tight junction protein occludin were downregulated in both HF/HSD and LF/HSD fed rats. HF/HSD and LF/HSD-fed rats also exhibited an increase in cecum and serum levels of lipopolysaccharide (LPS), a pro-inflammatory bacterial product. Immunofluorescence revealed the withdrawal of vagal afferents from the gut and at their site of termination the nucleus of the solitary tract (NTS) in both the HF/HSD and LF/HSD rats. Moreover, there was significant microglia activation in the nodose ganglia, which contain the vagal afferent neuron cell bodies, of HF/HSD and LF/HSD rats. Taken together, these data indicate that, similar to HF/HSD, consumption of an LF/HSD induces dysbiosis of gut microbiota, increases gut inflammation and alters vagal gut-brain communication. These changes are associated with an increase in body fat accumulation.
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Affiliation(s)
- Tanusree Sen
- Department of Veterinary Biosciences & Diagnostic Imaging, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, United States
| | - Carolina R Cawthon
- Department of Foods and Nutrition, College of Family and Consumer Sciences, University of Georgia, Athens, GA 30602, United States
| | - Benjamin Thomas Ihde
- Department of Veterinary Biosciences & Diagnostic Imaging, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, United States
| | - Andras Hajnal
- The Pennsylvania State University, College of Medicine, Neural and Behavioral Sciences, Hershey, PA 17033, United States
| | | | - Claire B de La Serre
- Department of Foods and Nutrition, College of Family and Consumer Sciences, University of Georgia, Athens, GA 30602, United States.
| | - Krzysztof Czaja
- Department of Veterinary Biosciences & Diagnostic Imaging, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, United States.
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36
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Hankir MK, Seyfried F, Hintschich CA, Diep TA, Kleberg K, Kranz M, Deuther-Conrad W, Tellez LA, Rullmann M, Patt M, Teichert J, Hesse S, Sabri O, Brust P, Hansen HS, de Araujo IE, Krügel U, Fenske WK. Gastric Bypass Surgery Recruits a Gut PPAR-α-Striatal D1R Pathway to Reduce Fat Appetite in Obese Rats. Cell Metab 2017; 25:335-344. [PMID: 28065827 DOI: 10.1016/j.cmet.2016.12.006] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 10/19/2016] [Accepted: 12/10/2016] [Indexed: 12/25/2022]
Abstract
Bariatric surgery remains the single most effective long-term treatment modality for morbid obesity, achieved mainly by lowering caloric intake through as yet ill-defined mechanisms. Here we show in rats that Roux-en-Y gastric bypass (RYGB)-like rerouting of ingested fat mobilizes lower small intestine production of the fat-satiety molecule oleoylethanolamide (OEA). This was associated with vagus nerve-driven increases in dorsal striatal dopamine release. We also demonstrate that RYGB upregulates striatal dopamine 1 receptor (D1R) expression specifically under high-fat diet feeding conditions. Mechanistically, interfering with local OEA, vagal, and dorsal striatal D1R signaling negated the beneficial effects of RYGB on fat intake and preferences. These findings delineate a molecular/systems pathway through which bariatric surgery improves feeding behavior and may aid in the development of novel weight loss strategies that similarly modify brain reward circuits compromised in obesity.
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Affiliation(s)
- Mohammed K Hankir
- Integrated Research and Treatment Centre for Adiposity Diseases, Department of Medicine, Universität Leipzig, Liebigstraße 21, 04103 Leipzig, Germany
| | - Florian Seyfried
- Department of General and Visceral, Vascular, and Paediatric Surgery, University of Würzburg, 97070 Würzburg, Germany
| | - Constantin A Hintschich
- Integrated Research and Treatment Centre for Adiposity Diseases, Department of Medicine, Universität Leipzig, Liebigstraße 21, 04103 Leipzig, Germany
| | - Thi-Ai Diep
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B Building 18.5, 2200 Copenhagen, Denmark
| | - Karen Kleberg
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 1165 Copenhagen, Denmark
| | - Mathias Kranz
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, 04318 Leipzig, Germany
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, 04318 Leipzig, Germany
| | - Luis A Tellez
- John B. Pierce Laboratory and Departments of Psychiatry and Physiology, Yale University, New Haven, CT 06519, USA
| | - Michael Rullmann
- Department of Nuclear Medicine, Universität Leipzig, Liebigstraße 18, 04109 Leipzig, Germany
| | - Marianne Patt
- Department of Nuclear Medicine, Universität Leipzig, Liebigstraße 18, 04109 Leipzig, Germany
| | - Jens Teichert
- Rudolf Boehm Institute of Pharmacology and Toxicology, Clinical Pharmacology, Universität Leipzig, Härtelstraße 16-18, 04107 Leipzig, Germany
| | - Swen Hesse
- Integrated Research and Treatment Centre for Adiposity Diseases, Department of Medicine, Universität Leipzig, Liebigstraße 21, 04103 Leipzig, Germany; Department of Nuclear Medicine, Universität Leipzig, Liebigstraße 18, 04109 Leipzig, Germany
| | - Osama Sabri
- Integrated Research and Treatment Centre for Adiposity Diseases, Department of Medicine, Universität Leipzig, Liebigstraße 21, 04103 Leipzig, Germany; Department of Nuclear Medicine, Universität Leipzig, Liebigstraße 18, 04109 Leipzig, Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, 04318 Leipzig, Germany
| | - Harald S Hansen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 1165 Copenhagen, Denmark
| | - Ivan E de Araujo
- John B. Pierce Laboratory and Departments of Psychiatry and Physiology, Yale University, New Haven, CT 06519, USA
| | - Ute Krügel
- Rudolf Boehm Institute of Pharmacology and Toxicology, Universität Leipzig, Härtelstraße 16-18, 04107 Leipzig, Germany.
| | - Wiebke K Fenske
- Integrated Research and Treatment Centre for Adiposity Diseases, Department of Medicine, Universität Leipzig, Liebigstraße 21, 04103 Leipzig, Germany.
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de Lartigue G, Diepenbroek C. Novel developments in vagal afferent nutrient sensing and its role in energy homeostasis. Curr Opin Pharmacol 2016; 31:38-43. [PMID: 27591963 DOI: 10.1016/j.coph.2016.08.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/01/2016] [Accepted: 08/11/2016] [Indexed: 12/16/2022]
Abstract
Vagal afferent neurons (VANs) play an important role in the control of food intake by signaling nutrient type and quantity to the brain. Recent findings are broadening our view of how VANs impact not only food intake but also energy homeostasis. This review focuses exclusively on studies of the vagus nerve from the past 2 years that highlight major new advancements in the field. We firstly discuss evidence that VANs can directly sense nutrients, and we consider new insights into mechanisms affecting sensing of gastric distension and signaling by gastrointestinal hormones ghrelin and GLP1. We discuss evidence that disrupting vagal afferent signaling increases long-term control of food intake and body weight management, and the importance of this gut-brain pathway in mediating beneficial effects of bariatric surgery. We conclude by highlighting novel roles for vagal afferent neurons in circadian rhythm, thermogenesis, and reward that may provide insight into mechanisms by which VAN nutrient sensing controls long-term control of energy homeostasis.
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Affiliation(s)
- Guillaume de Lartigue
- The John B. Pierce Laboratory, New Haven, CT, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.
| | - Charlene Diepenbroek
- The John B. Pierce Laboratory, New Haven, CT, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
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Madden CJ, Morrison SF. A high-fat diet impairs cooling-evoked brown adipose tissue activation via a vagal afferent mechanism. Am J Physiol Endocrinol Metab 2016; 311:E287-92. [PMID: 27354235 PMCID: PMC5005966 DOI: 10.1152/ajpendo.00081.2016] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 06/23/2016] [Indexed: 01/01/2023]
Abstract
In dramatic contrast to rats on a control diet, rats maintained on a high-fat diet (HFD) failed to activate brown adipose tissue (BAT) during cooling despite robust increases in their BAT activity following direct activation of their BAT sympathetic premotor neurons in the raphe pallidus. Cervical vagotomy or blockade of glutamate receptors in the nucleus of the tractus solitarii (NTS) reversed the HFD-induced inhibition of cold-evoked BAT activity. Thus, a HFD does not prevent rats from mounting a robust, centrally driven BAT thermogenesis; however, a HFD does alter a vagal afferent input to NTS neurons, thereby preventing the normal activation of BAT thermogenesis to cooling. These results, paralleling the absence of cooling-evoked glucose uptake in the BAT of obese humans, reveal a neural mechanism through which consumption of a HFD contributes to reduced energy expenditure and thus to weight gain.
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Affiliation(s)
- Christopher J Madden
- Department of Neurological Surgery, Oregon Health and Science University, Portland, Oregon
| | - Shaun F Morrison
- Department of Neurological Surgery, Oregon Health and Science University, Portland, Oregon
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Abstract
Excess and ectopic fat accumulation in obesity is a major risk factor for developing hyperlipidemia, type 2 diabetes and cardiovascular disease. The activation of brown and/or beige adipocytes is a promising target for the treatment of metabolic disorders as the combustion of excess energy by these thermogenic adipocytes may help losing weight and improving plasma parameters including triglyceride, cholesterol and glucose levels. The regulation of heat production by thermogenic adipose tissues is based on a complex crosstalk between the autonomous nervous system, intracellular and secreted factors. This multifaceted alignment regulates thermogenic demands to environmental circumstances in dependence on available energy resources. This review summarizes the current knowledge how thermogenic tissues can be targeted to combat the burden of diseases with a special focus on lipid metabolism and diseases related to lipoprotein metabolism.
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Affiliation(s)
- Christian Schlein
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
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40
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FGF21 ameliorates the neurocontrol of blood pressure in the high fructose-drinking rats. Sci Rep 2016; 6:29582. [PMID: 27387420 PMCID: PMC4937430 DOI: 10.1038/srep29582] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 06/23/2016] [Indexed: 11/11/2022] Open
Abstract
Fibroblast growth factor-21 (FGF21) is closely related to various metabolic and cardiovascular disorders. However, the direct targets and mechanisms linking FGF21 to blood pressure control and hypertension are still elusive. Here we demonstrated a novel regulatory function of FGF21 in the baroreflex afferent pathway (the nucleus tractus solitarii, NTS; nodose ganglion, NG). As the critical co-receptor of FGF21, β-klotho (klb) significantly expressed on the NTS and NG. Furthermore, we evaluated the beneficial effects of chronic intraperitoneal infusion of recombinant human FGF21 (rhFGF21) on the dysregulated systolic blood pressure, cardiac parameters, baroreflex sensitivity (BRS) and hyperinsulinemia in the high fructose-drinking (HFD) rats. The BRS up-regulation is associated with Akt-eNOS-NO signaling activation in the NTS and NG induced by acute intravenous rhFGF21 administration in HFD and control rats. Moreover, the expressions of FGF21 receptors were aberrantly down-regulated in HFD rats. In addition, the up-regulated peroxisome proliferator-activated receptor-γ and -α (PPAR-γ/-α) in the NTS and NG in HFD rats were markedly reversed by chronic rhFGF21 infusion. Our study extends the work of the FGF21 actions on the neurocontrol of blood pressure regulations through baroreflex afferent pathway in HFD rats.
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41
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Liu L, Lin Y, Liu L, Wang L, Bian Y, Gao X, Li Q. Regulation of peroxisome proliferator-activated receptor gamma on milk fat synthesis in dairy cow mammary epithelial cells. In Vitro Cell Dev Biol Anim 2016; 52:1044-1059. [DOI: 10.1007/s11626-016-0059-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 05/18/2016] [Indexed: 12/26/2022]
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Abstract
Increasing energy expenditure is an appealing therapeutic target for the prevention and reversal of metabolic conditions such as obesity or type 2 diabetes. However, not enough research has investigated how to exploit pre-existing neural pathways, both in the central nervous system (CNS) and peripheral nervous system (PNS), in order to meet these needs. Here, we review several research areas in this field, including centrally acting pathways known to drive the activation of sympathetic nerves that can increase lipolysis and browning in white adipose tissue (WAT) or increase thermogenesis in brown adipose tissue (BAT), as well as other central and peripheral pathways able to increase energy expenditure of these tissues. In addition, we describe new work investigating the family of transient receptor potential (TRP) channels on metabolically important sensory nerves, as well as the role of the vagus nerve in regulating energy balance.
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Affiliation(s)
- Magdalena Blaszkiewicz
- School of Biology and Ecology and Graduate School of Biomedical Sciences and Engineering, University of Maine, 5735 Hitchner Hall, Rm 301, Orono, ME, 04469, USA
| | - Kristy L Townsend
- School of Biology and Ecology and Graduate School of Biomedical Sciences and Engineering, University of Maine, 5735 Hitchner Hall, Rm 301, Orono, ME, 04469, USA.
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43
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Krieger JP, Arnold M, Pettersen KG, Lossel P, Langhans W, Lee SJ. Knockdown of GLP-1 Receptors in Vagal Afferents Affects Normal Food Intake and Glycemia. Diabetes 2016; 65:34-43. [PMID: 26470787 DOI: 10.2337/db15-0973] [Citation(s) in RCA: 164] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/16/2015] [Indexed: 11/13/2022]
Abstract
Nutrient stimulation of enteroendocrine L cells induces the release of the incretin and satiating peptide glucagon-like peptide 1 (GLP-1). The vagus nerve innervates visceral organs and may contribute to the mediation of gut-derived GLP-1's effects on food intake, energy homeostasis, and glycemic control. To test the hypothesis that vagal afferent neuron (VAN) GLP-1 receptors (GLP-1Rs) are necessary for these effects of endogenous GLP-1, we established a novel bilateral nodose ganglia injection technique to deliver a lentiviral vector and to knock down VAN GLP-1Rs in male Sprague Dawley rats. We found that a full expression of VAN GLP-1Rs is not necessary for the maintenance of long-term energy balance in normal eating conditions. VAN GLP-1R knockdown (kd) did, however, increase meal size and accelerated gastric emptying. Moreover, postmeal glycemia was elevated and insulin release was blunted in GLP-1R kd rats, suggesting that VAN GLP-1Rs are physiological contributors to the neuroincretin effect after a meal. Collectively, our results highlight a crucial role for the VANs in mediating the effects of endogenous GLP-1 on food intake and glycemia and may promote the further development of GLP-1-based therapies.
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Affiliation(s)
- Jean-Philippe Krieger
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
| | - Myrtha Arnold
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
| | - Klaus G Pettersen
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
| | - Pius Lossel
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
| | - Shin J Lee
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
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Krieger JP, Langhans W, Lee SJ. Vagal mediation of GLP-1's effects on food intake and glycemia. Physiol Behav 2015; 152:372-80. [DOI: 10.1016/j.physbeh.2015.06.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/29/2015] [Accepted: 06/01/2015] [Indexed: 12/17/2022]
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Abstract
The essential role of the brain in maintaining energy homeostasis has motivated the drive to define the neural circuitry that integrates external and internal stimuli to enact appropriate and consequential metabolic and behavioral responses. The hypothalamus has received significant attention in this regard given its ability to influence feeding behavior, yet organisms rely on a much broader diversity and distribution of neuronal networks to regulate both energy intake and expenditure. Because energy balance is a fundamental determinant of survival and success of an organism, it is not surprising that emerging data connect circuits controlling feeding and energy balance with higher brain functions and degenerative processes. In this review, we will highlight both classically defined and emerging aspects of brain control of energy homeostasis.
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Affiliation(s)
- Michael J Waterson
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Tamas L Horvath
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA.
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Abstract
Since brown adipose tissue (BAT) dissipates energy through UCP1, BAT has garnered attention as a therapeutic intervention for obesity and metabolic diseases including type 2 diabetes. As we better understand the physiological roles of classical brown and beige adipocytes, it is becoming clear that BAT is not simply a heat-generating organ. Increased beige fat mass in response to a variety of external/internal cues is associated with significant improvements in glucose and lipid homeostasis that may not be entirely mediated by UCP1. We aim to discuss recent insights regarding the developmental lineages, molecular regulation, and new functions for brown and beige adipocytes.
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Affiliation(s)
- Shingo Kajimura
- UCSF Diabetes Center and Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143-0669, USA.
| | - Bruce M Spiegelman
- Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02215, USA.
| | - Patrick Seale
- Institute for Diabetes, Obesity, and Metabolism, Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Liu Y, Huang Y, Lee S, Bookout AL, Castorena CM, Wu H, Gautron L. PPARγ mRNA in the adult mouse hypothalamus: distribution and regulation in response to dietary challenges. Front Neuroanat 2015; 9:120. [PMID: 26388745 PMCID: PMC4558427 DOI: 10.3389/fnana.2015.00120] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 08/20/2015] [Indexed: 11/13/2022] Open
Abstract
Peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-activated transcription factor that was originally identified as a regulator of peroxisome proliferation and adipocyte differentiation. Emerging evidence suggests that functional PPARγ signaling also occurs within the hypothalamus. However, the exact distribution and identities of PPARγ-expressing hypothalamic cells remains under debate. The present study systematically mapped PPARγ mRNA expression in the adult mouse brain using in situ hybridization histochemistry. PPARγ mRNA was found to be expressed at high levels outside the hypothalamus including the neocortex, the olfactory bulb, the organ of the vasculosum of the lamina terminalis (VOLT), and the subfornical organ. Within the hypothalamus, PPARγ was present at moderate levels in the suprachiasmatic nucleus (SCh) and the ependymal of the 3rd ventricle. In all examined feeding-related hypothalamic nuclei, PPARγ was expressed at very low levels that were close to the limit of detection. Using qPCR techniques, we demonstrated that PPARγ mRNA expression was upregulated in the SCh in response to fasting. Double in situ hybridization further demonstrated that PPARγ was primarily expressed in neurons rather than glia. Collectively, our observations provide a comprehensive map of PPARγ distribution in the intact adult mouse hypothalamus.
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Affiliation(s)
- Yang Liu
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA ; Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology Wuhan, China
| | - Ying Huang
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Syann Lee
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Angie L Bookout
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Carlos M Castorena
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Hua Wu
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology Wuhan, China
| | - Laurent Gautron
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
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Mansuy-Aubert V, Gautron L, Lee S, Bookout AL, Kusminski C, Sun K, Zhang Y, Scherer PE, Mangelsdorf DJ, Elmquist JK. Loss of the liver X receptor LXRα/β in peripheral sensory neurons modifies energy expenditure. eLife 2015; 4. [PMID: 26076474 PMCID: PMC4467361 DOI: 10.7554/elife.06667] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Accepted: 05/14/2015] [Indexed: 11/13/2022] Open
Abstract
Peripheral neural sensory mechanisms play a crucial role in metabolic regulation but less is known about the mechanisms underlying vagal sensing itself. Recently, we identified an enrichment of liver X receptor alpha and beta (LXRα/β) in the nodose ganglia of the vagus nerve. In this study, we show mice lacking LXRα/β in peripheral sensory neurons have increased energy expenditure and weight loss when fed a Western diet (WD). Our findings suggest that the ability to metabolize and sense cholesterol and/or fatty acids in peripheral neurons is an important requirement for physiological adaptations to WDs. DOI:http://dx.doi.org/10.7554/eLife.06667.001 The vagus nerves run from the brainstem to the heart and the digestive system and help to control several processes including digestion and heart rate. Because of their role in regulating food intake, these nerves are attractive targets for scientists hoping to develop treatments for obesity. There are two types of fat tissue found in mammals: white fat, which is used as an energy store and makes up most of the extra fat seen in obese individuals; and brown fat, which can generate body heat. The vagus nerves monitor fat and cholesterol levels in the body via receptor proteins that respond to messages sent from the fat tissues and the liver. Previous research unexpectedly found that mice genetically engineered to lack these receptor proteins—called LXRα and LXRβ—do not become obese even when fed a high-fat, high-cholesterol diet that would make normal mice gain excessive weight. Mansuy-Aubert et al. have now investigated in more detail why mice without these receptor proteins are resistant to obesity. When fed a high-fat, high-cholesterol diet, mice that lacked the LXRα and LXRβ receptors in sensory neurons had higher cholesterol levels in their nerve cells than normal mice on the same diet. Mice lacking these receptors also burned more energy and gained less weight than normal mice. Next, Mansuy-Aubert et al. examined fat tissue from both types of mice. This revealed that the heat-generating brown fat was more active in mice lacking the LXRα and LXRβ receptors. Some of the white fat in these mice had also become more like brown fat, allowing the mice to burn more energy and so gain less weight. In many Western countries, many people also eat a diet that is high in fat and cholesterol. This raises the possibility that drugs that block the LXRα and LXRβ receptors in sensory neurons in humans could help to treat or prevent obesity, although further work will be needed to investigate this. DOI:http://dx.doi.org/10.7554/eLife.06667.002
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Affiliation(s)
- Virginie Mansuy-Aubert
- Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Laurent Gautron
- Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Syann Lee
- Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Angie L Bookout
- Department of Pharmacology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Christine Kusminski
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Kai Sun
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Yuan Zhang
- Department of Pharmacology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - David J Mangelsdorf
- Department of Pharmacology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joel K Elmquist
- Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
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Marciano DP, Kuruvilla DS, Boregowda SV, Asteian A, Hughes TS, Garcia-Ordonez R, Corzo CA, Khan TM, Novick SJ, Park H, Kojetin DJ, Phinney DG, Bruning JB, Kamenecka TM, Griffin PR. Pharmacological repression of PPARγ promotes osteogenesis. Nat Commun 2015; 6:7443. [PMID: 26068133 PMCID: PMC4471882 DOI: 10.1038/ncomms8443] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 05/06/2015] [Indexed: 11/25/2022] Open
Abstract
The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) is the master regulator of adipogenesis and the pharmacological target of the thiazolidinedione (TZD) class of insulin sensitizers. Activation of PPARγ by TZDs promotes adipogenesis at the expense of osteoblast formation, contributing to their associated adverse effects on bone. Recently we reported the development of PPARγ antagonist SR1664, designed to block the obesity induced phosphorylation of serine 273 (S273) in the absence of classical agonism, to derive insulin sensitizing efficacy with improved therapeutic index. Here we identify the structural mechanism by which SR1664 actively antagonizes PPARγ, and extend these findings to develop the inverse agonist SR2595. Treatment of isolated bone marrow derived mesenchymal stem cells (MSCs) with SR2595 promotes induction of osteogenic differentiation. Together these results identify the structural determinants of ligand mediated PPARγ repression, and suggest a therapeutic approach to promote bone formation.
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Affiliation(s)
- David P Marciano
- Departments of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter FL33458, USA
| | - Dana S Kuruvilla
- Departments of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter FL33458, USA
| | - Siddaraju V Boregowda
- Departments of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter FL33458, USA
| | - Alice Asteian
- Departments of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter FL33458, USA
| | - Travis S Hughes
- Departments of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter FL33458, USA
| | - Ruben Garcia-Ordonez
- Departments of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter FL33458, USA
| | - Cesar A Corzo
- Departments of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter FL33458, USA
| | - Tanya M Khan
- Departments of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter FL33458, USA
| | - Scott J Novick
- Departments of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter FL33458, USA
| | - HaJeung Park
- Departments of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter FL33458, USA
| | - Douglas J Kojetin
- Departments of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter FL33458, USA
| | - Donald G Phinney
- Departments of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter FL33458, USA
| | - John B Bruning
- School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Theodore M Kamenecka
- Departments of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter FL33458, USA
| | - Patrick R Griffin
- Departments of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter FL33458, USA
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50
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Evaluation of the synuclein-γ (SNCG) gene as a PPARγ target in murine adipocytes, dorsal root ganglia somatosensory neurons, and human adipose tissue. PLoS One 2015; 10:e0115830. [PMID: 25756178 PMCID: PMC4355072 DOI: 10.1371/journal.pone.0115830] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 12/02/2014] [Indexed: 11/19/2022] Open
Abstract
Recent evidence in adipocytes points to a role for synuclein-γ in metabolism and lipid droplet dynamics, but interestingly this factor is also robustly expressed in peripheral neurons. Specific regulation of the synuclein-γ gene (Sncg) by PPARγ requires further evaluation, especially in peripheral neurons, prompting us to test if Sncg is a bona fide PPARγ target in murine adipocytes and peripheral somatosensory neurons derived from the dorsal root ganglia (DRG). Sncg mRNA was decreased in 3T3-L1 adipocytes (~68%) by rosiglitazone, and this effect was diminished by the PPARγ antagonist T0070907. Chromatin immunoprecipitation experiments confirmed PPARγ protein binding at two promoter sequences of Sncg during 3T3-L1 adipogenesis. Rosiglitazone did not affect Sncg mRNA expression in murine cultured DRG neurons. In subcutaneous human WAT samples from two cohorts treated with pioglitazone (>11 wks), SNCG mRNA expression was reduced, albeit highly variable and most evident in type 2 diabetes. Leptin (Lep) expression, thought to be coordinately-regulated with Sncg based on correlations in human adipose tissue, was also reduced in 3T3-L1 adipocytes by rosiglitazone. However, Lep was unaffected by PPARγ antagonist, and the LXR agonist T0901317 significantly reduced Lep expression (~64%) while not impacting Sncg. The results support the concept that synuclein-γ shares some, but not all, gene regulators with leptin and is a PPARγ target in adipocytes but not DRG neurons. Regulation of synuclein-γ by cues such as PPARγ agonism in adipocytes is logical based on recent evidence for an important role for synuclein-γ in the maintenance and dynamics of adipocyte lipid droplets.
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