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Huang L, Liu P, Du Y, Pan D, Lee A, Wolfe SA, Wang YX. A brown fat-enriched adipokine, ASRA, is a leptin receptor antagonist that stimulates appetite. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.12.557454. [PMID: 37745491 PMCID: PMC10515849 DOI: 10.1101/2023.09.12.557454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The endocrine control of food intake remains incompletely understood, and whether the leptin receptor-mediated anorexigenic pathway in the hypothalamus is negatively regulated by a humoral factor is unknown. Here we identify an appetite-stimulating factor - ASRA - that acts as a leptin receptor antagonist. ASRA encodes an 8 kD protein that is abundantly and selectively expressed in adipose tissue and to a lesser extent, in liver, and is upregulated during fasting and cold. ASRA protein associates with autophagosomes and its secretion is induced by energy deficiency. Overexpression of ASRA in mice attenuates leptin receptor signaling leading to elevated blood glucose and development of severe hyperphagic obesity, whereas either adipose- or liver-specific ASRA knockout mice display increased leptin sensitivity, improved glucose homeostasis, reduced food intake, and resistance to high fat diet-induced obesity. Furthermore, ASRA is indispensable for cold-evoked feeding response. Recombinant ASRA (rASRA) protein binds to leptin receptor and suppresses leptin receptor signaling in cultured cells. In vivo, rASRA promotes food intake and increases blood glucose in a leptin receptor signaling-dependent manner. Our studies collectively show that ASRA, acting as a peripheral signal of energy deficit, stimulates appetite and regulates glucose metabolism by antagonizing leptin receptor signaling, thus revealing a previously unknown endocrine mechanism that has important implications for our understanding of leptin resistance.
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Affiliation(s)
- Lei Huang
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- These authors contributed equally to this work: Lei Huang, Pengpeng Liu, and Yong Du
| | - Pengpeng Liu
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Chan Medical School, Worcester, MA, USA
- These authors contributed equally to this work: Lei Huang, Pengpeng Liu, and Yong Du
| | - Yong Du
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- These authors contributed equally to this work: Lei Huang, Pengpeng Liu, and Yong Du
| | - Dongning Pan
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Present address: Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, Fudan University Shanghai Medical College, Shanghai, China
| | - Alexandra Lee
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Scot A. Wolfe
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Yong-Xu Wang
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
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Álvarez-Almazán S, Solís-Domínguez LC, Duperou-Luna P, Fuerte-Gómez T, González-Andrade M, Aranda-Barradas ME, Palacios-Espinosa JF, Pérez-Villanueva J, Matadamas-Martínez F, Miranda-Castro SP, Mercado-Márquez C, Cortés-Benítez F. Anti-Diabetic Activity of Glycyrrhetinic Acid Derivatives FC-114 and FC-122: Scale-Up, In Silico, In Vitro, and In Vivo Studies. Int J Mol Sci 2023; 24:12812. [PMID: 37628991 PMCID: PMC10454726 DOI: 10.3390/ijms241612812] [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: 06/30/2023] [Revised: 08/07/2023] [Accepted: 08/12/2023] [Indexed: 08/27/2023] Open
Abstract
Type 2 diabetes (T2D) is one of the most common diseases and the 8th leading cause of death worldwide. Individuals with T2D are at risk for several health complications that reduce their life expectancy and quality of life. Although several drugs for treating T2D are currently available, many of them have reported side effects ranging from mild to severe. In this work, we present the synthesis in a gram-scale as well as the in silico and in vitro activity of two semisynthetic glycyrrhetinic acid (GA) derivatives (namely FC-114 and FC-122) against Protein Tyrosine Phosphatase 1B (PTP1B) and α-glucosidase enzymes. Furthermore, the in vitro cytotoxicity assay on Human Foreskin fibroblast and the in vivo acute oral toxicity was also conducted. The anti-diabetic activity was determined in streptozotocin-induced diabetic rats after oral administration with FC-114 or FC-122. Results showed that both GA derivatives have potent PTP1B inhibitory activity being FC-122, a dual PTP1B/α-glucosidase inhibitor that could increase insulin sensitivity and reduce intestinal glucose absorption. Molecular docking, molecular dynamics, and enzymatic kinetics studies revealed the inhibition mechanism of FC-122 against α-glucosidase. Both GA derivatives were safe and showed better anti-diabetic activity in vivo than the reference drug acarbose. Moreover, FC-114 improves insulin levels while decreasing LDL and total cholesterol levels without decreasing HDL cholesterol.
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Affiliation(s)
- Samuel Álvarez-Almazán
- Laboratory of Biotechnology, Unidad de Posgrado, Facultad de Estudios Superiores Cuautitlán Campus 1, Universidad Nacional Autónoma de México, Cuautitlán Izcalli 54740, Mexico; (S.Á.-A.); (L.C.S.-D.); (T.F.-G.); (M.E.A.-B.); (S.P.M.-C.)
| | - Luz Cassandra Solís-Domínguez
- Laboratory of Biotechnology, Unidad de Posgrado, Facultad de Estudios Superiores Cuautitlán Campus 1, Universidad Nacional Autónoma de México, Cuautitlán Izcalli 54740, Mexico; (S.Á.-A.); (L.C.S.-D.); (T.F.-G.); (M.E.A.-B.); (S.P.M.-C.)
| | - Paulina Duperou-Luna
- Laboratory of Synthesis and Isolation of Bioactive Substances, Departamento de Sistemas Biológicos, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana–Xochimilco (UAM–X), Mexico City 04960, Mexico; (P.D.-L.); (J.F.P.-E.); (J.P.-V.); (F.M.-M.)
| | - Teresa Fuerte-Gómez
- Laboratory of Biotechnology, Unidad de Posgrado, Facultad de Estudios Superiores Cuautitlán Campus 1, Universidad Nacional Autónoma de México, Cuautitlán Izcalli 54740, Mexico; (S.Á.-A.); (L.C.S.-D.); (T.F.-G.); (M.E.A.-B.); (S.P.M.-C.)
| | - Martin González-Andrade
- Laboratory of Biosensors and Molecular Modelling, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico;
| | - María E. Aranda-Barradas
- Laboratory of Biotechnology, Unidad de Posgrado, Facultad de Estudios Superiores Cuautitlán Campus 1, Universidad Nacional Autónoma de México, Cuautitlán Izcalli 54740, Mexico; (S.Á.-A.); (L.C.S.-D.); (T.F.-G.); (M.E.A.-B.); (S.P.M.-C.)
| | - Juan Francisco Palacios-Espinosa
- Laboratory of Synthesis and Isolation of Bioactive Substances, Departamento de Sistemas Biológicos, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana–Xochimilco (UAM–X), Mexico City 04960, Mexico; (P.D.-L.); (J.F.P.-E.); (J.P.-V.); (F.M.-M.)
| | - Jaime Pérez-Villanueva
- Laboratory of Synthesis and Isolation of Bioactive Substances, Departamento de Sistemas Biológicos, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana–Xochimilco (UAM–X), Mexico City 04960, Mexico; (P.D.-L.); (J.F.P.-E.); (J.P.-V.); (F.M.-M.)
| | - Félix Matadamas-Martínez
- Laboratory of Synthesis and Isolation of Bioactive Substances, Departamento de Sistemas Biológicos, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana–Xochimilco (UAM–X), Mexico City 04960, Mexico; (P.D.-L.); (J.F.P.-E.); (J.P.-V.); (F.M.-M.)
| | - Susana Patricia Miranda-Castro
- Laboratory of Biotechnology, Unidad de Posgrado, Facultad de Estudios Superiores Cuautitlán Campus 1, Universidad Nacional Autónoma de México, Cuautitlán Izcalli 54740, Mexico; (S.Á.-A.); (L.C.S.-D.); (T.F.-G.); (M.E.A.-B.); (S.P.M.-C.)
| | - Crisóforo Mercado-Márquez
- Isolation and Animal Facility Unit, Facultad de Estudios Superiores Cuautitlán 28, Universidad Nacional Autónoma de México, Cuautitlán Izcalli 54714, Mexico;
| | - Francisco Cortés-Benítez
- Laboratory of Synthesis and Isolation of Bioactive Substances, Departamento de Sistemas Biológicos, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana–Xochimilco (UAM–X), Mexico City 04960, Mexico; (P.D.-L.); (J.F.P.-E.); (J.P.-V.); (F.M.-M.)
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3
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Shaik Mohamed Sayed UF, Moshawih S, Goh HP, Kifli N, Gupta G, Singh SK, Chellappan DK, Dua K, Hermansyah A, Ser HL, Ming LC, Goh BH. Natural products as novel anti-obesity agents: insights into mechanisms of action and potential for therapeutic management. Front Pharmacol 2023; 14:1182937. [PMID: 37408757 PMCID: PMC10318930 DOI: 10.3389/fphar.2023.1182937] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 06/06/2023] [Indexed: 07/07/2023] Open
Abstract
Obesity affects more than 10% of the adult population globally. Despite the introduction of diverse medications aimed at combating fat accumulation and obesity, a significant number of these pharmaceutical interventions are linked to substantial occurrences of severe adverse events, occasionally leading to their withdrawal from the market. Natural products serve as attractive sources for anti-obesity agents as many of them can alter the host metabolic processes and maintain glucose homeostasis via metabolic and thermogenic stimulation, appetite regulation, pancreatic lipase and amylase inhibition, insulin sensitivity enhancing, adipogenesis inhibition and adipocyte apoptosis induction. In this review, we shed light on the biological processes that control energy balance and thermogenesis as well as metabolic pathways in white adipose tissue browning, we also highlight the anti-obesity potential of natural products with their mechanism of action. Based on previous findings, the crucial proteins and molecular pathways involved in adipose tissue browning and lipolysis induction are uncoupling protein-1, PR domain containing 16, and peroxisome proliferator-activated receptor-γ in addition to Sirtuin-1 and AMP-activated protein kinase pathway. Given that some phytochemicals can also lower proinflammatory substances like TNF-α, IL-6, and IL-1 secreted from adipose tissue and change the production of adipokines like leptin and adiponectin, which are important regulators of body weight, natural products represent a treasure trove for anti-obesity agents. In conclusion, conducting comprehensive research on natural products holds the potential to accelerate the development of an improved obesity management strategy characterized by heightened efficacy and reduced incidence of side effects.
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Affiliation(s)
| | - Said Moshawih
- PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Gadong, Brunei
| | - Hui Poh Goh
- PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Gadong, Brunei
| | - Nurolaini Kifli
- PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Gadong, Brunei
| | - Gaurav Gupta
- School of Pharmacy, Suresh Gyan Vihar University, Jaipur, India
- Department of Pharmacology, Saveetha Institute of Medical and Technical Sciences, Saveetha Dental College and Hospitals, Saveetha University, Chennai, India
| | - Sachin Kumar Singh
- Faculty of Health, Australian Research Centre in Complementary and Integrative Medicine, University of Technology Sydney, Ultimo, NSW, Australia
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, India
| | - Dinesh Kumar Chellappan
- Department of Life Sciences, School of Pharmacy, International Medical University, Kuala Lumpur, Malaysia
| | - Kamal Dua
- Faculty of Health, Australian Research Centre in Complementary and Integrative Medicine, University of Technology Sydney, Ultimo, NSW, Australia
- Discipline of Pharmacy, Graduate School of Health, University of Technology Sydney, Ultimo, NSW, Australia
- Uttaranchal Institute of Pharmaceutical Sciences, Uttaranchal University, Dehradun, India
| | - Andi Hermansyah
- Department of Pharmacy Practice, Faculty of Pharmacy, Universitas AirlanggaSurabaya, Indonesia
| | - Hooi Leng Ser
- School of Medical and Life Sciences, Sunway University, Sunway, Malaysia
| | - Long Chiau Ming
- PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Gadong, Brunei
- Department of Pharmacy Practice, Faculty of Pharmacy, Universitas AirlanggaSurabaya, Indonesia
- School of Medical and Life Sciences, Sunway University, Sunway, Malaysia
| | - Bey Hing Goh
- Biofunctional Molecule Exploratory Research Group, School of Pharmacy, Monash University Malaysia, Bandar Sunway, Malaysia
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
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4
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Plakkot B, Di Agostino A, Subramanian M. Implications of Hypothalamic Neural Stem Cells on Aging and Obesity-Associated Cardiovascular Diseases. Cells 2023; 12:cells12050769. [PMID: 36899905 PMCID: PMC10000584 DOI: 10.3390/cells12050769] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/14/2023] [Accepted: 02/25/2023] [Indexed: 03/06/2023] Open
Abstract
The hypothalamus, one of the major regulatory centers in the brain, controls various homeostatic processes, and hypothalamic neural stem cells (htNSCs) have been observed to interfere with hypothalamic mechanisms regulating aging. NSCs play a pivotal role in the repair and regeneration of brain cells during neurodegenerative diseases and rejuvenate the brain tissue microenvironment. The hypothalamus was recently observed to be involved in neuroinflammation mediated by cellular senescence. Cellular senescence, or systemic aging, is characterized by a progressive irreversible state of cell cycle arrest that causes physiological dysregulation in the body and it is evident in many neuroinflammatory conditions, including obesity. Upregulation of neuroinflammation and oxidative stress due to senescence has the potential to alter the functioning of NSCs. Various studies have substantiated the chances of obesity inducing accelerated aging. Therefore, it is essential to explore the potential effects of htNSC dysregulation in obesity and underlying pathways to develop strategies to address obesity-induced comorbidities associated with brain aging. This review will summarize hypothalamic neurogenesis associated with obesity and prospective NSC-based regenerative therapy for the treatment of obesity-induced cardiovascular conditions.
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Suh SB, Lee N, Kim J, Kim S, Jang S, Park JK, Lee K, Choi SY, Kwon HJ, Lee CH. Metformin ameliorates olanzapine-induced obesity and glucose intolerance by regulating hypothalamic inflammation and microglial activation in female mice. Front Pharmacol 2022; 13:906717. [PMID: 36313357 PMCID: PMC9596779 DOI: 10.3389/fphar.2022.906717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 09/26/2022] [Indexed: 11/16/2022] Open
Abstract
Olanzapine (OLZ), a widely used second-generation antipsychotic drug, is known to cause metabolic side effects, including diabetes and obesity. Interestingly, OLZ-induced metabolic side effects have been demonstrated to be more profound in females in human studies and animal models. Metformin (MET) is often used as a medication for the metabolic side effects of OLZ. However, the mechanisms underlying OLZ-induced metabolic disturbances and their treatment remain unclear. Recent evidence has suggested that hypothalamic inflammation is a key component of the pathophysiology of metabolic disorders. On this background, we conducted this study with the following three objectives: 1) to investigate whether OLZ can independently induce hypothalamic microgliosis; 2) to examine whether there are sex-dependent differences in OLZ-induced hypothalamic microgliosis; and 3) to examine whether MET affects hypothalamic microgliosis. We found that administration of OLZ for 5 days induced systemic glucose intolerance and hypothalamic microgliosis and inflammation. Of note, both hypothalamic microglial activation and systemic glucose intolerance were far more evident in female mice than in male mice. The administration of MET attenuated hypothalamic microglial activation and prevented OLZ-induced systemic glucose intolerance and hypothalamic leptin resistance. Minocycline, a tetracycline derivative that prevents microgliosis, showed similar results when centrally injected. Our findings reveal that OLZ induces metabolic disorders by causing hypothalamic inflammation and that this inflammation is alleviated by MET administration.
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Affiliation(s)
- Sang Bum Suh
- University of Ulsan College of Medicine, Seoul, South Korea
| | - Nayoung Lee
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Jaedeok Kim
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Saeha Kim
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Sooyeon Jang
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Jong Kook Park
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Keunwook Lee
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Soo Young Choi
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Hyung-Joo Kwon
- Department of Microbiology, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Chan Hee Lee
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
- Program of Material Science for Medicine and Pharmaceutics, Hallym University, Chuncheon, South Korea
- *Correspondence: Chan Hee Lee,
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6
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Kim J, Lee N, Suh SB, Jang S, Kim S, Kim DG, Park JK, Lee KW, Choi SY, Lee CH. Metformin ameliorates olanzapine-induced disturbances in POMC neuron number, axonal projection, and hypothalamic leptin resistance. BMB Rep 2022. [PMID: 35651327 PMCID: PMC9252891 DOI: 10.5483/bmbrep.2022.55.6.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Antipsychotics have been widely accepted as a treatment of choice for psychiatric illnesses such as schizophrenia. While atypical antipsychotics such as aripiprazole are not associated with obesity and diabetes, olanzapine is still widely used based on the anticipation that it is more effective in treating severe schizophrenia than aripiprazole, despite its metabolic side effects. To address metabolic problems, metformin is widely prescribed. Hypothalamic proopiomelanocortin (POMC) neurons have been identified as the main regulator of metabolism and energy expenditure. Although the relation between POMC neurons and metabolic disorders is well established, little is known about the effects of olanzapine and metformin on hypothalamic POMC neurons. In the present study, we investigated the effect of olanzapine and metformin on the hypothalamic POMC neurons in female mice. Olanzapine administration for 5 days significantly decreased Pomc mRNA expression, POMC neuron numbers, POMC projections, and induced leptin resistance before the onset of obesity. It was also observed that coadministration of metformin with olanzapine not only increased POMC neuron numbers and projections but also improved the leptin response of POMC neurons in the olanzapine-treated female mice. These findings suggest that olanzapine-induced hypothalamic POMC neuron abnormality and leptin resistance, which can be ameliorated by metformin administration, are the possible causes of subsequent hyperphagia.
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Affiliation(s)
- Jaedeok Kim
- Department of Biomedical Science, Hallym University, Chuncheon 24252, Korea
| | - Nayoung Lee
- Department of Biomedical Science, Hallym University, Chuncheon 24252, Korea
| | - Sang Bum Suh
- University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Sooyeon Jang
- Department of Biomedical Science, Hallym University, Chuncheon 24252, Korea
| | - Saeha Kim
- Department of Biomedical Science, Hallym University, Chuncheon 24252, Korea
| | - Dong-Gyu Kim
- Department of Biomedical Science, Hallym University, Chuncheon 24252, Korea
| | - Jong Kook Park
- Department of Biomedical Science, Hallym University, Chuncheon 24252, Korea
| | - Keun-Wook Lee
- Department of Biomedical Science, Hallym University, Chuncheon 24252, Korea
| | - Soo Young Choi
- Department of Biomedical Science, Hallym University, Chuncheon 24252, Korea
| | - Chan Hee Lee
- Department of Biomedical Science, Hallym University, Chuncheon 24252, Korea
- Program of Material Science for Medicine and Pharmaceutics, Hallym University, Chuncheon 24252, Korea
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7
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Vohra MS, Benchoula K, Serpell CJ, Hwa WE. AgRP/NPY and POMC neurons in the arcuate nucleus and their potential role in treatment of obesity. Eur J Pharmacol 2022; 915:174611. [PMID: 34798121 DOI: 10.1016/j.ejphar.2021.174611] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 10/27/2021] [Accepted: 10/27/2021] [Indexed: 02/08/2023]
Abstract
Obesity is a major health crisis affecting over a third of the global population. This multifactorial disease is regulated via interoceptive neural circuits in the brain, whose alteration results in excessive body weight. Certain central neuronal populations in the brain are recognised as crucial nodes in energy homeostasis; in particular, the hypothalamic arcuate nucleus (ARC) region contains two peptide microcircuits that control energy balance with antagonistic functions: agouti-related peptide/neuropeptide-Y (AgRP/NPY) signals hunger and stimulates food intake; and pro-opiomelanocortin (POMC) signals satiety and reduces food intake. These neuronal peptides levels react to energy status and integrate signals from peripheral ghrelin, leptin, and insulin to regulate feeding and energy expenditure. To manage obesity comprehensively, it is crucial to understand cellular and molecular mechanisms of information processing in ARC neurons, since these regulate energy homeostasis. Importantly, a specific strategy focusing on ARC circuits needs to be devised to assist in treating obese patients and maintaining weight loss with minimal or no side effects. The aim of this review is to elucidate the recent developments in the study of AgRP-, NPY- and POMC-producing neurons, specific to their role in controlling metabolism. The impact of ghrelin, leptin, and insulin signalling via action of these neurons is also surveyed, since they also impact energy balance through this route. Lastly, we present key proteins, targeted genes, compounds, drugs, and therapies that actively work via these neurons and could potentially be used as therapeutic targets for treating obesity conditions.
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Affiliation(s)
- Muhammad Sufyan Vohra
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Khaled Benchoula
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Christopher J Serpell
- School of Physical Sciences, Ingram Building, University of Kent, Canterbury, Kent, CT2 7NH, United Kingdom
| | - Wong Eng Hwa
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia.
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8
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Teimouri M, Hosseini H, ArabSadeghabadi Z, Babaei-Khorzoughi R, Gorgani-Firuzjaee S, Meshkani R. The role of protein tyrosine phosphatase 1B (PTP1B) in the pathogenesis of type 2 diabetes mellitus and its complications. J Physiol Biochem 2022; 78:307-322. [PMID: 34988903 DOI: 10.1007/s13105-021-00860-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 11/16/2021] [Indexed: 01/16/2023]
Abstract
Insulin resistance, the most important characteristic of the type 2 diabetes mellitus (T2DM), is mostly caused by impairment in the insulin receptor (IR) signal transduction pathway. Protein tyrosine phosphatase 1B (PTP1B), one of the main negative regulators of the IR signaling pathway, is broadly expressed in various cells and tissues. PTP1B decreases the phosphorylation of the IR resulting in insulin resistance in various tissues. The evidence for the physiological role of PTP1B in regulation of metabolic pathways came from whole-body PTP1B-knockout mice. Whole-body and tissue-specific PTP1B-knockout mice showed improvement in adiposity, insulin resistance, and glucose tolerance. In addition, the key role of PTP1B in the pathogenesis of T2DM and its complications was further investigated in mice models of PTP1B deficient/overexpression. In recent years, targeting PTP1B using PTP1B inhibitors is being considered an attractive target to treat T2DM. PTP1B inhibitors improve the sensitivity of the insulin receptor and have the ability to cure insulin resistance-related diseases. We herein summarized the biological functions of PTP1B in different tissues in vivo and in vitro. We also describe the effectiveness of potent PTP1B inhibitors as pharmaceutical agents to treat T2DM.
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Affiliation(s)
- Maryam Teimouri
- Department of Clinical Biochemistry, School of Allied Medical Sciences, Shahroud University of Medical Sciences, Shahroud, Iran
| | - Hossein Hosseini
- Department of Clinical Biochemistry, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Zahra ArabSadeghabadi
- Department of Clinical Sciences, Faculty of Veterinary Science, Bu-Ali Sina University, Hamedan, Iran
| | - Reyhaneh Babaei-Khorzoughi
- Department of Clinical Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Sattar Gorgani-Firuzjaee
- Department of Medical Laboratory Sciences, School of Allied Health Medicine, AJA University of Medical Sciences, Tehran, Iran
| | - Reza Meshkani
- Department of Clinical Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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9
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Lockridge A, Hanover JA. A nexus of lipid and O-Glcnac metabolism in physiology and disease. Front Endocrinol (Lausanne) 2022; 13:943576. [PMID: 36111295 PMCID: PMC9468787 DOI: 10.3389/fendo.2022.943576] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 07/27/2022] [Indexed: 11/13/2022] Open
Abstract
Although traditionally considered a glucose metabolism-associated modification, the O-linked β-N-Acetylglucosamine (O-GlcNAc) regulatory system interacts extensively with lipids and is required to maintain lipid homeostasis. The enzymes of O-GlcNAc cycling have molecular properties consistent with those expected of broad-spectrum environmental sensors. By direct protein-protein interactions and catalytic modification, O-GlcNAc cycling enzymes may provide both acute and long-term adaptation to stress and other environmental stimuli such as nutrient availability. Depending on the cell type, hyperlipidemia potentiates or depresses O-GlcNAc levels, sometimes biphasically, through a diversity of unique mechanisms that target UDP-GlcNAc synthesis and the availability, activity and substrate selectivity of the glycosylation enzymes, O-GlcNAc Transferase (OGT) and O-GlcNAcase (OGA). At the same time, OGT activity in multiple tissues has been implicated in the homeostatic regulation of systemic lipid uptake, storage and release. Hyperlipidemic patterns of O-GlcNAcylation in these cells are consistent with both transient physiological adaptation and feedback uninhibited obesogenic and metabolic dysregulation. In this review, we summarize the numerous interconnections between lipid and O-GlcNAc metabolism. These links provide insights into how the O-GlcNAc regulatory system may contribute to lipid-associated diseases including obesity and metabolic syndrome.
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10
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Indole- and Pyrazole-Glycyrrhetinic Acid Derivatives as PTP1B Inhibitors: Synthesis, In Vitro and In Silico Studies. Molecules 2021; 26:molecules26144375. [PMID: 34299651 PMCID: PMC8308021 DOI: 10.3390/molecules26144375] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 07/13/2021] [Accepted: 07/18/2021] [Indexed: 11/17/2022] Open
Abstract
Regulating insulin and leptin levels using a protein tyrosine phosphatase 1B (PTP1B) inhibitor is an attractive strategy to treat diabetes and obesity. Glycyrrhetinic acid (GA), a triterpenoid, may weakly inhibit this enzyme. Nonetheless, semisynthetic derivatives of GA have not been developed as PTP1B inhibitors to date. Herein we describe the synthesis and evaluation of two series of indole- and N-phenylpyrazole-GA derivatives (4a-f and 5a-f). We measured their inhibitory activity and enzyme kinetics against PTP1B using p-nitrophenylphosphate (pNPP) assay. GA derivatives bearing substituted indoles or N-phenylpyrazoles fused to their A-ring showed a 50% inhibitory concentration for PTP1B in a range from 2.5 to 10.1 µM. The trifluoromethyl derivative of indole-GA (4f) exhibited non-competitive inhibition of PTP1B as well as higher potency (IC50 = 2.5 µM) than that of positive controls ursolic acid (IC50 = 5.6 µM), claramine (IC50 = 13.7 µM) and suramin (IC50 = 4.1 µM). Finally, docking and molecular dynamics simulations provided the theoretical basis for the favorable activity of the designed compounds.
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11
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Beddows CA, Dodd GT. Insulin on the brain: The role of central insulin signalling in energy and glucose homeostasis. J Neuroendocrinol 2021; 33:e12947. [PMID: 33687120 DOI: 10.1111/jne.12947] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/26/2021] [Accepted: 01/28/2021] [Indexed: 12/26/2022]
Abstract
Insulin signals to the brain where it coordinates multiple physiological processes underlying energy and glucose homeostasis. This review explores where and how insulin interacts within the brain parenchyma, how brain insulin signalling functions to coordinate energy and glucose homeostasis and how this contributes to the pathogenesis of metabolic disease.
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Affiliation(s)
- Cait A Beddows
- Department of Anatomy and Physiology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Garron T Dodd
- Department of Anatomy and Physiology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC, Australia
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12
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Sergi D, Williams LM. Potential relationship between dietary long-chain saturated fatty acids and hypothalamic dysfunction in obesity. Nutr Rev 2020; 78:261-277. [PMID: 31532491 DOI: 10.1093/nutrit/nuz056] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Diet-induced hypothalamic inflammation, which leads to hypothalamic dysfunction and a loss of regulation of energy balance, is emerging as a potential driver of obesity. Excessive intake of long-chain saturated fatty acids is held to be the causative dietary component in hypothalamic inflammation. This review summarizes current evidence on the role of long-chain saturated fatty acids in promoting hypothalamic inflammation and the related induction of central insulin and leptin insensitivity. Particularly, the present review focuses on the molecular mechanisms linking long-chain saturated fatty acids and hypothalamic inflammation, emphasizing the metabolic fate of fatty acids and the resulting lipotoxicity, which is a key driver of hypothalamic dysfunction. In conclusion, long-chain saturated fatty acids are key nutrients that promote hypothalamic inflammation and dysfunction by fostering the build-up of lipotoxic lipid species, such as ceramide. Furthermore, when long-chain saturated fatty acids are consumed in combination with high levels of refined carbohydrates, the proinflammatory effects are exacerbated via a mechanism that relies on the formation of advanced glycation end products.
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Affiliation(s)
- Domenico Sergi
- Nutrition and Health Substantiation Group, Nutrition and Health Program, Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Adelaide, South Australia, Australia
| | - Lynda M Williams
- Rowett Institute, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
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13
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Abstract
Tau protein which was discovered in 1975 [310] became of great interest when it was identified as the main component of neurofibrillary tangles (NFT), a pathological feature in the brain of patients with Alzheimer's disease (AD) [39, 110, 232]. Tau protein is expressed mainly in the brain as six isoforms generated by alternative splicing [46, 97]. Tau is a microtubule associated proteins (MAPs) and plays a role in microtubules assembly and stability, as well as diverse cellular processes such as cell morphogenesis, cell division, and intracellular trafficking [49]. Additionally, Tau is involved in much larger neuronal functions particularly at the level of synapses and nuclei [11, 133, 280]. Tau is also physiologically released by neurons [233] even if the natural function of extracellular Tau remains to be uncovered (see other chapters of the present book).
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14
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Lee CH, Kim HJ, Lee YS, Kang GM, Lim HS, Lee SH, Song DK, Kwon O, Hwang I, Son M, Byun K, Sung YH, Kim S, Kim JB, Choi EY, Kim YB, Kim K, Kweon MN, Sohn JW, Kim MS. Hypothalamic Macrophage Inducible Nitric Oxide Synthase Mediates Obesity-Associated Hypothalamic Inflammation. Cell Rep 2019; 25:934-946.e5. [PMID: 30355499 PMCID: PMC6284237 DOI: 10.1016/j.celrep.2018.09.070] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 06/13/2018] [Accepted: 09/21/2018] [Indexed: 02/08/2023] Open
Abstract
Obesity-associated metabolic alterations are closely linked to low-grade
inflammation in peripheral organs, in which macrophages play a central role.
Using genetic labeling of myeloid lineage cells, we show that hypothalamic
macrophages normally reside in the perivascular area and circumventricular organ
median eminence. Chronic consumption of a high-fat diet (HFD) induces expansion
of the monocyte-derived macrophage pool in the hypothalamic arcuate nucleus
(ARC), which is significantly attributed to enhanced proliferation of
macrophages. Notably, inducible nitric oxide synthase (iNOS) is robustly
activated in ARC macrophages of HFD-fed obese mice. Hypothalamic macrophage iNOS
inhibition completely abrogates macrophage accumulation and activation,
proinflammatory cytokine overproduction, reactive astrogliosis,
blood-brain-barrier permeability, and lipid accumulation in the ARC of obese
mice. Moreover, central iNOS inhibition improves obesity-induced alterations in
systemic glucose metabolism without affecting adiposity. Our findings suggest a
critical role for hypothalamic macrophage-expressed iNOS in hypothalamic
inflammation and abnormal glucose metabolism in cases of overnutrition-induced
obesity. Lee et al. demonstrate in mice that, upon prolonged high-fat diet
feeding, hypothalamic macrophages proliferate, expand their pool, and sustain
hypothalamic inflammation. Moreover, they show that hypothalamic macrophage iNOS
inhibition diminishes macrophage activation, astrogliosis, blood-brain-barrier
permeability, and impaired glucose metabolism in diet-induced obese mice.
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Affiliation(s)
- Chan Hee Lee
- Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Hyo Jin Kim
- Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul 05505, Korea; Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Yong-Soo Lee
- Department of Convergence Medicine, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Gil Myoung Kang
- Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Hyo Sun Lim
- Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul 05505, Korea; Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Seung-Hwan Lee
- Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Do Kyeong Song
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Obin Kwon
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Injae Hwang
- National Creative Research Initiatives Center for Adipose Tissue Remodeling, School of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, Korea
| | - Myeongjoo Son
- Department of Anatomy and Cell Biology, Gachon University College of Medicine, Incheon 21565, Korea
| | - Kyunghee Byun
- Department of Anatomy and Cell Biology, Gachon University College of Medicine, Incheon 21565, Korea
| | - Young Hoon Sung
- Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul 05505, Korea; Department of Convergence Medicine, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Seyun Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Jae Bum Kim
- National Creative Research Initiatives Center for Adipose Tissue Remodeling, School of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, Korea
| | - Eun Young Choi
- Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Young-Bum Kim
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Keetae Kim
- Department of New Biology, DGIST, Daegu 42988, Korea
| | - Mi-Na Kweon
- Department of Convergence Medicine, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Jong-Woo Sohn
- Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Min-Seon Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Ulsan College of Medicine, Seoul 05505, Korea.
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Goto N, Tsujimoto M, Nagai H, Masaki T, Ito S, Wakamatsu K, Nishigori C. 4-(4-Hydroxyphenyl)-2-butanol (rhododendrol)-induced melanocyte cytotoxicity is enhanced by UVB exposure through generation of oxidative stress. Exp Dermatol 2019; 27:754-762. [PMID: 29630780 DOI: 10.1111/exd.13555] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2018] [Indexed: 02/06/2023]
Abstract
4-(4-Hydroxyphenyl)-2-butanol (rhododendrol, RD), a skin-whitening agent, was reported to cause skin depigmentation in some users, which is attributed to its cytotoxicity to melanocyte. It was reported that cytotoxicity to melanocyte is possibly mediated by oxidative stress in a tyrosinase activity-dependent manner. We examined the effect of UV radiation (UVR) on RD-induced melanocyte cytotoxicity as an additional aggravating factor. UVR enhanced RD-induced cytotoxicity in normal human epidermal melanocytes (NHEMs) via the induction of endoplasmic reticulum (ER) stress. Increased generation of intracellular reactive oxygen species (ROS) was detected. Pretreatment with N-acetyl cysteine (NAC), antioxidant and precursor of glutathione significantly attenuated ER stress-induced cytotoxicity in NHEMs treated with RD and UVR. Increase in cysteinyl-RD-catechol and RD-pheomelanin in NHEMs treated with RD and UVR suggested that, after UVR excitation, RD or RD metabolites are potent ROS-generating substances and that the tendency to produce RD-pheomelanin during melanogenesis amplifies ROS generation in melanocytes. Our results help to elucidate the development mechanisms of RD-induced leukoderma and provide information for innovation of safe skin-whitening compounds.
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Affiliation(s)
- Noriko Goto
- Department of Dermatology, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Mariko Tsujimoto
- Department of Dermatology, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Hiroshi Nagai
- Department of Dermatology, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Taro Masaki
- Department of Dermatology, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Shosuke Ito
- Department of Chemistry, Fujita Health University School of Health Sciences, Toyake, Aichi, Japan
| | - Kazumasa Wakamatsu
- Department of Chemistry, Fujita Health University School of Health Sciences, Toyake, Aichi, Japan
| | - Chikako Nishigori
- Department of Dermatology, Graduate School of Medicine, Kobe University, Kobe, Japan
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16
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Molecular Mechanisms of Hypothalamic Insulin Resistance. Int J Mol Sci 2019; 20:ijms20061317. [PMID: 30875909 PMCID: PMC6471380 DOI: 10.3390/ijms20061317] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/07/2019] [Accepted: 03/13/2019] [Indexed: 02/06/2023] Open
Abstract
Insulin exists in the central nervous system, where it executes two important functions in the hypothalamus: the suppression of food intake and the improvement of glucose metabolism. Recent studies have shown that both are exerted robustly in rodents and humans. If intact, these functions exert beneficial effects on obesity and diabetes, respectively. Disruption of both occurs due to a condition known as hypothalamic insulin resistance, which is caused by obesity and the overconsumption of saturated fat. An enormous volume of literature addresses the molecular mechanisms of hypothalamic insulin resistance. IKKβ and JNK are major players in the inflammation pathway, which is activated by saturated fatty acids that induce hypothalamic insulin resistance. Two major tyrosine phosphatases, PTP-1B and TCPTP, are upregulated in chronic overeating. They dephosphorylate the insulin receptor and insulin receptor substrate proteins, resulting in hypothalamic insulin resistance. Prolonged hyperinsulinemia with excessive nutrition activates the mTOR/S6 kinase pathway, thereby enhancing IRS-1 serine phosphorylation to induce hypothalamic insulin resistance. Other mechanisms associated with this condition include hypothalamic gliosis and disturbed insulin transport into the central nervous system. Unveiling the precise molecular mechanisms involved in hypothalamic insulin resistance is important for developing new ways of treating obesity and type 2 diabetes.
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17
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DiNicolantonio JJ, McCarty M, OKeefe J. Does elevated bilirubin aid weight control by preventing development of hypothalamic leptin resistance? Open Heart 2019; 6:e000897. [PMID: 30997121 PMCID: PMC6443125 DOI: 10.1136/openhrt-2018-000897] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/04/2019] [Indexed: 12/16/2022] Open
Affiliation(s)
| | | | - James OKeefe
- Preventive Cardiology, Mid America Heart Institute, Kansas City, Missouri, USA
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18
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Yagi M, Nakatsuji Y, Maeda A, Ota H, Kamikubo R, Miyoshi N, Nakamura Y, Akagawa M. Phenethyl isothiocyanate activates leptin signaling and decreases food intake. PLoS One 2018; 13:e0206748. [PMID: 30383868 PMCID: PMC6211728 DOI: 10.1371/journal.pone.0206748] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 10/18/2018] [Indexed: 12/31/2022] Open
Abstract
Obesity, a principal risk factor for the development of diabetes mellitus, heart disease, and hypertension, is a growing and serious health problem all over the world. Leptin is a weight-reducing hormone produced by adipose tissue, which decreases food intake via hypothalamic leptin receptors (Ob-Rb) and the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway. Protein tyrosine phosphatase 1B (PTP1B) negatively regulates leptin signaling by dephosphorylating JAK2, and the increased activity of PTP1B is implicated in the pathogenesis of obesity. Hence, inhibition of PTP1B may help prevent and reduce obesity. In this study, we revealed that phenethyl isothiocyanate (PEITC), a naturally occurring isothiocyanate in certain cruciferous vegetables, potently inhibits recombinant PTP1B by binding to the reactive cysteinyl thiol. Moreover, we found that PEITC causes the ligand-independent phosphorylation of Ob-Rb, JAK2, and STAT3 by inhibiting cellular PTP1B in differentiated human SH-SY5Y neuronal cells. PEITC treatment also induced nuclear accumulation of phosphorylated STAT3, resulting in enhanced anorexigenic POMC expression and suppressed orexigenic NPY/AGRP expression. We demonstrated that oral administration of PEITC to mice significantly reduces food intake, and stimulates hypothalamic leptin signaling. Our results suggest that PEITC might help prevent and improve obesity.
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Affiliation(s)
- Miho Yagi
- Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Yukiko Nakatsuji
- Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Ayumi Maeda
- Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Hiroki Ota
- Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Ryosuke Kamikubo
- Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Noriyuki Miyoshi
- Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
| | - Yoshimasa Nakamura
- Graduate School of Environmental and Life Science, Okayama University, Okayama, Japan
| | - Mitsugu Akagawa
- Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
- * E-mail:
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19
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Perakakis N, Ghaly W, Peradze N, Boutari C, Batirel S, Douglas VP, Mantzoros CS. Research advances in metabolism 2017. Metabolism 2018; 83:280-289. [PMID: 29378200 DOI: 10.1016/j.metabol.2018.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 01/19/2018] [Indexed: 11/19/2022]
Affiliation(s)
- Nikolaos Perakakis
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
| | - Wael Ghaly
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA; Department of Physiology, Fayoum University, Fayoum, Egypt
| | - Natia Peradze
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Chrysoula Boutari
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Saime Batirel
- Department of Medical Biochemistry, Faculty of Medicine, Marmara University, Istanbul 34854, Turkey; Genetic and Metabolic Diseases Research Center (GEMHAM), Marmara University, Istanbul 34854, Turkey
| | - Vivian Paraskevi Douglas
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Christos S Mantzoros
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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20
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Dodd GT, Tiganis T. Insulin action in the brain: Roles in energy and glucose homeostasis. J Neuroendocrinol 2017; 29. [PMID: 28758251 DOI: 10.1111/jne.12513] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 07/05/2017] [Accepted: 07/26/2017] [Indexed: 12/14/2022]
Abstract
A growing body of evidence from research in rodents and humans has identified insulin as an important neuoregulatory peptide in the brain, where it coordinates diverse aspects of energy balance and peripheral glucose homeostasis. This review discusses where and how insulin interacts within the brain and evaluates the physiological and pathophysiological consequences of central insulin signalling in metabolism, obesity and type 2 diabetes.
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Affiliation(s)
- G T Dodd
- Metabolic Disease and Obesity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, Australia
| | - T Tiganis
- Metabolic Disease and Obesity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, Australia
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21
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Liu JY, Mu S, Zhang SP, Guo W, Li QF, Xiao XQ, Zhang J, Wang ZH. Roux-en-Y gastric bypass surgery suppresses hypothalamic PTP1B protein level and alleviates leptin resistance in obese rats. Exp Ther Med 2017; 14:2536-2542. [PMID: 28947917 PMCID: PMC5609316 DOI: 10.3892/etm.2017.4801] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 02/13/2017] [Indexed: 12/20/2022] Open
Abstract
The present study aimed to explore the effect of Roux-en-Y gastric bypass (RYGB) surgery on protein tyrosine phosphatase 1B (PTP1B) expression levels and leptin activity in hypothalami of obese rats. Obese rats induced by a high-fat diet (HFD) that underwent RYGB (n=11) or sham operation (SO, n=9), as well as an obese control cohort (Obese, n=10) and an additional normal-diet group (ND, n=10) were used. Food efficiency was measured at 8 weeks post-operation. Plasma leptin levels were evaluated and hypothalamic protein tyrosine phosphatase 1B (PTP1B) levels and leptin signaling activity were examined at the genetic and protein levels. The results indicated that food efficiency was typically lower in RYGB rats compared with that in the Obese and SO rats. In the RYGB group, leptin receptor expression and proopiomelanocortin was significantly higher, while Neuropeptide Y levels were lower than those in the Obese and SO groups. Furthermore, the gene and protein expression levels of PTP1B in the RYGB group were lower, while levels of phosphorylated signal transducer and activator of transcription 3 protein were much higher compared with those in the Obese and SO groups. In conclusion, RYGB surgery significantly suppressed hypothalamic PTP1B protein expression. PTP1B regulation may partially alleviate leptin resistance.
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Affiliation(s)
- Jia-Yu Liu
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Song Mu
- Department of General Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Shu-Ping Zhang
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Wei Guo
- Department of General Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Qi-Fu Li
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Xiao-Qiu Xiao
- Laboratory of Lipid and Glucose Metabolism, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Jun Zhang
- Department of General Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Zhi-Hong Wang
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
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22
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Sugiyama M, Banno R, Mizoguchi A, Tominaga T, Tsunekawa T, Onoue T, Hagiwara D, Ito Y, Morishita Y, Iwama S, Goto M, Suga H, Arima H. PTP1B deficiency improves hypothalamic insulin sensitivity resulting in the attenuation of AgRP mRNA expression under high-fat diet conditions. Biochem Biophys Res Commun 2017; 488:116-121. [PMID: 28479249 DOI: 10.1016/j.bbrc.2017.05.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 05/03/2017] [Indexed: 11/19/2022]
Abstract
Hypothalamic insulin receptor signaling regulates energy balance and glucose homeostasis via agouti-related protein (AgRP). While protein tyrosine phosphatase 1B (PTP1B) is classically known to be a negative regulator of peripheral insulin signaling by dephosphorylating both insulin receptor β (IRβ) and insulin receptor substrate, the role of PTP1B in hypothalamic insulin signaling remains to be fully elucidated. In the present study, we investigated the role of PTP1B in hypothalamic insulin signaling using PTP1B deficient (KO) mice in vivo and ex vivo. For the in vivo study, hypothalamic insulin resistance induced by a high-fat diet (HFD) improved in KO mice compared to wild-type (WT) mice. Hypothalamic AgRP mRNA expression levels were also significantly decreased in KO mice independent of body weight changes. In an ex vivo study using hypothalamic organotypic cultures, insulin treatment significantly increased the phosphorylation of both IRβ and Akt in the hypothalamus of KO mice compared to WT mice, and also significantly decreased AgRP mRNA expression levels in KO mice. While incubation with inhibitors of phosphatidylinositol-3 kinase (PI3K) had no effect on basal levels of Akt phosphorylation, these suppressed insulin induction of Akt phosphorylation to almost basal levels in WT and KO mice. The inhibition of the PI3K-Akt pathway blocked the downregulation of AgRP mRNA expression in KO mice treated with insulin. These data suggest that PTP1B acts on the hypothalamic insulin signaling via the PI3K-Akt pathway. Together, our results suggest a deficiency of PTP1B improves hypothalamic insulin sensitivity resulting in the attenuation of AgRP mRNA expression under HFD conditions.
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Affiliation(s)
- Mariko Sugiyama
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Ryoichi Banno
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Akira Mizoguchi
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Takashi Tominaga
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Taku Tsunekawa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Takeshi Onoue
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Daisuke Hagiwara
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Yoshihiro Ito
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Yoshiaki Morishita
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Shintaro Iwama
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan; Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya 464-8601, Japan
| | - Motomitsu Goto
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Hidetaka Suga
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Hiroshi Arima
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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Mendes NF, Castro G, Guadagnini D, Tobar N, Cognuck SQ, Elias LLK, Boer PA, Prada PO. Knocking down amygdalar PTP1B in diet-induced obese rats improves insulin signaling/action, decreases adiposity and may alter anxiety behavior. Metabolism 2017; 70:1-11. [PMID: 28403933 DOI: 10.1016/j.metabol.2017.01.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 01/03/2017] [Accepted: 01/27/2017] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Protein tyrosine phosphatase 1B (PTP1B) has been extensively implicated in the regulation of body weight, food intake, and energy expenditure. The role of PTP1B appears to be cell and brain region dependent. RESULTS Herein, we demonstrated that chronic high-fat feeding enhanced PTP1B expression in the central nucleus of the amygdala (CeA) of rats compared to rats on chow. Knocking down PTP1B with oligonucleotide antisense (ASO) decreased its expression and was sufficient to improve the anorexigenic effect of insulin through IR/Akt signaling in the CeA. ASO treatment reduces body weight, fat mass, serum leptin levels, and food intake and also increases energy expenditure, without altering ambulatory activity. These changes were explained, at least in part, by the improvement of insulin sensitivity in the CeA, decreasing NPY and enhancing oxytocin expression. There was a slight decline in fasting blood glucose and serum insulin levels possibly due to leanness in rats treated with ASO. Surprisingly, the elevated plus maze test revealed an anxiolytic behavior after reduction of PTP1B in the CeA. CONCLUSIONS Thus, the present study highlights the deleterious role that the amygdalar PTP1B has on energy homeostasis in obesity states. The reduction of PTP1B in the CeA may be a strategy for the treatment of obesity, insulin resistance and anxiety disorders.
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Affiliation(s)
| | - Gisele Castro
- Department of Internal Medicine, State University of Campinas, UNICAMP, Brazil
| | - Dioze Guadagnini
- Department of Internal Medicine, State University of Campinas, UNICAMP, Brazil
| | - Natalia Tobar
- Department of Internal Medicine, State University of Campinas, UNICAMP, Brazil
| | - Susana Quiros Cognuck
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, USP, Brazil
| | | | - Patricia Aline Boer
- Department of Internal Medicine, State University of Campinas, UNICAMP, Brazil
| | - Patricia Oliveira Prada
- School of Applied Sciences, State University of Campinas, UNICAMP, Brazil; Department of Internal Medicine, State University of Campinas, UNICAMP, Brazil.
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Abstract
The aim of this study was to investigate whether neonatal maternal separation (MS) - chronic stress experience in early life - affects the anorectic efficacy of leptin in the offspring at adolescence. Sprague-Dawley pups were separated from the dam daily for 3 h during postnatal day 1-14 or left undisturbed as non-handled controls (NH). NH and MS male pups received an intraperitoneal leptin (100 μg/kg) or saline on postnatal day (PND) 28, and then food intake and body weight gain were recorded. The hypothalamic levels of leptin-signalling-related genes, phosphorylated signal transducer and activator of transcription-3 (pSTAT3) and protein-tyrosine phosphatase 1B (PTP1B) were examined at 40 min after a single injection of leptin on PND 39 by immunohistochemistry and Western blot analysis. Leptin-induced suppressions in food intake and weight gain was observed in NH pups, but not in MS. Leptin increased pSTAT3 in the hypothalamic arcuate nucleus of NH pups, but not of MS. Interestingly, basal levels of the hypothalamic PTP1B and pSTAT3 were increased in MS pups compared with NH controls. The results suggest that neonatal MS experience may blunt the anorectic efficacy of leptin later in life, possibly in relation with increased expressions of PTP1B and/or pSTAT3 in the hypothalamus.
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Tsunekawa T, Banno R, Mizoguchi A, Sugiyama M, Tominaga T, Onoue T, Hagiwara D, Ito Y, Iwama S, Goto M, Suga H, Sugimura Y, Arima H. Deficiency of PTP1B Attenuates Hypothalamic Inflammation via Activation of the JAK2-STAT3 Pathway in Microglia. EBioMedicine 2017; 16:172-183. [PMID: 28094236 PMCID: PMC5474442 DOI: 10.1016/j.ebiom.2017.01.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/05/2017] [Accepted: 01/05/2017] [Indexed: 02/06/2023] Open
Abstract
Protein tyrosine phosphatase 1B (PTP1B) regulates leptin signaling in hypothalamic neurons via the JAK2-STAT3 pathway. PTP1B has also been implicated in the regulation of inflammation in the periphery. However, the role of PTP1B in hypothalamic inflammation, which is induced by a high-fat diet (HFD), remains to be elucidated. Here, we showed that STAT3 phosphorylation (p-STAT3) was increased in microglia in the hypothalamic arcuate nucleus of PTP1B knock-out mice (KO) on a HFD, accompanied by decreased Tnf and increased Il10 mRNA expression in the hypothalamus compared to wild-type mice (WT). In hypothalamic organotypic cultures, incubation with TNFα led to increased p-STAT3, accompanied by decreased Tnf and increased Il10 mRNA expression, in KO compared to WT. Incubation with p-STAT3 inhibitors or microglial depletion eliminated the differences in inflammation between genotypes. These data indicate an important role of JAK2-STAT3 signaling negatively regulated by PTP1B in microglia, which attenuates hypothalamic inflammation under HFD conditions.
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Affiliation(s)
- Taku Tsunekawa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Ryoichi Banno
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Akira Mizoguchi
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Mariko Sugiyama
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Takashi Tominaga
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Takeshi Onoue
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Daisuke Hagiwara
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Yoshihiro Ito
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Shintaro Iwama
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan; Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya 464-8601, Japan.
| | - Motomitsu Goto
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Hidetaka Suga
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Yoshihisa Sugimura
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Hiroshi Arima
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
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Athauda D, Foltynie T. Insulin resistance and Parkinson's disease: A new target for disease modification? Prog Neurobiol 2016; 145-146:98-120. [PMID: 27713036 DOI: 10.1016/j.pneurobio.2016.10.001] [Citation(s) in RCA: 200] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 09/28/2016] [Accepted: 10/02/2016] [Indexed: 12/12/2022]
Abstract
There is growing evidence that patients with Type 2 diabetes have an increased risk of developing Parkinson's disease and share similar dysregulated pathways suggesting common underlying pathological mechanisms. Historically insulin was thought solely to be a peripherally acting hormone responsible for glucose homeostasis and energy metabolism. However accumulating evidence indicates insulin can cross the blood-brain-barrier and influence a multitude of processes in the brain including regulating neuronal survival and growth, dopaminergic transmission, maintenance of synapses and pathways involved in cognition. In conjunction, there is growing evidence that a process analogous to peripheral insulin resistance occurs in the brains of Parkinson's disease patients, even in those without diabetes. This raises the possibility that defective insulin signalling pathways may contribute to the development of the pathological features of Parkinson's disease, and thereby suggests that the insulin signalling pathway may potentially be a novel target for disease modification. Given these growing links between PD and Type 2 diabetes it is perhaps not unsurprising that drugs used the treatment of T2DM are amongst the most promising treatments currently being prioritised for repositioning as possible novel treatments for PD and several clinical trials are under way. In this review, we will examine the underlying cellular links between insulin resistance and the pathogenesis of PD and then we will assess current and future pharmacological strategies being developed to restore neuronal insulin signalling as a potential strategy for slowing neurodegeneration in Parkinson's disease.
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Affiliation(s)
- D Athauda
- Sobell Department of Motor Neuroscience, UCL Institute of Neurology & The National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG, United Kingdom.
| | - T Foltynie
- Sobell Department of Motor Neuroscience, UCL Institute of Neurology & The National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG, United Kingdom.
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27
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Santos EW, de Oliveira DC, Hastreiter A, Beltran JSDO, Rogero MM, Fock RA, Borelli P. High-fat diet or low-protein diet changes peritoneal macrophages function in mice. ACTA ACUST UNITED AC 2016. [DOI: 10.1186/s41110-016-0006-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Zhang ZY, Dodd GT, Tiganis T. Protein Tyrosine Phosphatases in Hypothalamic Insulin and Leptin Signaling. Trends Pharmacol Sci 2016; 36:661-674. [PMID: 26435211 DOI: 10.1016/j.tips.2015.07.003] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 07/01/2015] [Accepted: 07/10/2015] [Indexed: 12/22/2022]
Abstract
The hypothalamus is critical to the coordination of energy balance and glucose homeostasis. It responds to peripheral factors, such as insulin and leptin, that convey to the brain the degree of adiposity and the metabolic status of the organism. The development of leptin and insulin resistance in hypothalamic neurons appears to have a key role in the exacerbation of diet-induced obesity. In rodents, this has been attributed partly to the increased expression of the tyrosine phosphatases Protein Tyrosine Phosphatase 1B (PTP1B) and T cell protein tyrosine phosphatase (TCPTP), which attenuate leptin and insulin signaling. Deficiencies in PTP1B and TCPTP in the brain, or specific neurons, promote insulin and leptin signaling and prevent diet-induced obesity, type 2 diabetes mellitus (T2DM), and fatty liver disease. Although targeting phosphatases and hypothalamic circuits remains challenging, recent advances indicate that such hurdles might be overcome. Here, we focus on the roles of PTP1B and TCPTP in insulin and leptin signaling and explore their potential as therapeutic targets.
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Affiliation(s)
- Zhong-Yin Zhang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202-5126, USA
| | - Garron T Dodd
- Department of Biochemistry and Molecular Biology, Monash University, VIC 3800, Australia
| | - Tony Tiganis
- Department of Biochemistry and Molecular Biology, Monash University, VIC 3800, Australia.
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29
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Kwon O, Kim KW, Kim MS. Leptin signalling pathways in hypothalamic neurons. Cell Mol Life Sci 2016; 73:1457-77. [PMID: 26786898 PMCID: PMC11108307 DOI: 10.1007/s00018-016-2133-1] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/20/2015] [Accepted: 01/07/2016] [Indexed: 12/25/2022]
Abstract
Leptin is the most critical hormone in the homeostatic regulation of energy balance among those so far discovered. Leptin primarily acts on the neurons of the mediobasal part of hypothalamus to regulate food intake, thermogenesis, and the blood glucose level. In the hypothalamic neurons, leptin binding to the long form leptin receptors on the plasma membrane initiates multiple signaling cascades. The signaling pathways known to mediate the actions of leptin include JAK-STAT signaling, PI3K-Akt-FoxO1 signaling, SHP2-ERK signaling, AMPK signaling, and mTOR-S6K signaling. Recent evidence suggests that leptin signaling in hypothalamic neurons is also linked to primary cilia function. On the other hand, signaling molecules/pathways mitigating leptin actions in hypothalamic neurons have been extensively investigated in an effort to treat leptin resistance observed in obesity. These include SOCS3, tyrosine phosphatase PTP1B, and inflammatory signaling pathways such as IKK-NFκB and JNK signaling, and ER stress-mitochondrial signaling. In this review, we discuss leptin signaling pathways in the hypothalamus, with a particular focus on the most recently discovered pathways.
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Affiliation(s)
- Obin Kwon
- Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea
- Appetite Regulation Laboratory, Asan Institute for Life Science, Seoul, 05505, Korea
| | - Ki Woo Kim
- Department of Pharmacology, Yonsei University Wonju College of Medicine, Wonju, 26426, Korea
- Department of Global Medical Science, Yonsei University Wonju College of Medicine, Wonju, 26426, Korea
| | - Min-Seon Kim
- Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea.
- Appetite Regulation Laboratory, Asan Institute for Life Science, Seoul, 05505, Korea.
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30
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Imbalanced insulin action in chronic over nutrition: Clinical harm, molecular mechanisms, and a way forward. Atherosclerosis 2016; 247:225-82. [PMID: 26967715 DOI: 10.1016/j.atherosclerosis.2016.02.004] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/31/2015] [Accepted: 02/02/2016] [Indexed: 02/08/2023]
Abstract
The growing worldwide prevalence of overnutrition and underexertion threatens the gains that we have made against atherosclerotic cardiovascular disease and other maladies. Chronic overnutrition causes the atherometabolic syndrome, which is a cluster of seemingly unrelated health problems characterized by increased abdominal girth and body-mass index, high fasting and postprandial concentrations of cholesterol- and triglyceride-rich apoB-lipoproteins (C-TRLs), low plasma HDL levels, impaired regulation of plasma glucose concentrations, hypertension, and a significant risk of developing overt type 2 diabetes mellitus (T2DM). In addition, individuals with this syndrome exhibit fatty liver, hypercoagulability, sympathetic overactivity, a gradually rising set-point for body adiposity, a substantially increased risk of atherosclerotic cardiovascular morbidity and mortality, and--crucially--hyperinsulinemia. Many lines of evidence indicate that each component of the atherometabolic syndrome arises, or is worsened by, pathway-selective insulin resistance and responsiveness (SEIRR). Individuals with SEIRR require compensatory hyperinsulinemia to control plasma glucose levels. The result is overdrive of those pathways that remain insulin-responsive, particularly ERK activation and hepatic de-novo lipogenesis (DNL), while carbohydrate regulation deteriorates. The effects are easily summarized: if hyperinsulinemia does something bad in a tissue or organ, that effect remains responsive in the atherometabolic syndrome and T2DM; and if hyperinsulinemia might do something good, that effect becomes resistant. It is a deadly imbalance in insulin action. From the standpoint of human health, it is the worst possible combination of effects. In this review, we discuss the origins of the atherometabolic syndrome in our historically unprecedented environment that only recently has become full of poorly satiating calories and incessant enticements to sit. Data are examined that indicate the magnitude of daily caloric imbalance that causes obesity. We also cover key aspects of healthy, balanced insulin action in liver, endothelium, brain, and elsewhere. Recent insights into the molecular basis and pathophysiologic harm from SEIRR in these organs are discussed. Importantly, a newly discovered oxide transport chain functions as the master regulator of the balance amongst different limbs of the insulin signaling cascade. This oxide transport chain--abbreviated 'NSAPP' after its five major proteins--fails to function properly during chronic overnutrition, resulting in this harmful pattern of SEIRR. We also review the origins of widespread, chronic overnutrition. Despite its apparent complexity, one factor stands out. A sophisticated junk food industry, aided by subsidies from willing governments, has devoted years of careful effort to promote overeating through the creation of a new class of food and drink that is low- or no-cost to the consumer, convenient, savory, calorically dense, yet weakly satiating. It is past time for the rest of us to overcome these foes of good health and solve this man-made epidemic.
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Hosoi T, Ozawa K. Possible Pharmacological Approach Targeting Endoplasmic Reticulum Stress to Ameliorate Leptin Resistance in Obesity. Front Endocrinol (Lausanne) 2016; 7:59. [PMID: 27375555 PMCID: PMC4896911 DOI: 10.3389/fendo.2016.00059] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/25/2016] [Indexed: 11/29/2022] Open
Abstract
Obesity is associated with metabolic syndrome, such as diabetes, hypertension, and hyperlipidemia. Therefore, drug development for the treatment of obesity is needed. Leptin is an anti-obesity hormone that inhibits food intake and increases energy metabolism, and, as such, treatments involving leptin were expected to be beneficial for obesity; however, since most obese patients are in a state of leptin resistance, these treatments may not be useful. Therefore, the amelioration of leptin resistance has recently been attracting interest as a treatment for obesity. The mechanisms underlying the development of leptin resistance need to be elucidated in more detail. Endoplasmic reticulum (ER) stress was recently suggested to be involved in the pathogenesis of leptin resistance. The molecular mechanisms responsible for leptin resistance and possible pharmacological treatments for obesity have been discussed herein, with a focus on ER stress.
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Affiliation(s)
- Toru Hosoi
- Department of Pharmacotherapy, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
- *Correspondence: Toru Hosoi, ; Koichiro Ozawa,
| | - Koichiro Ozawa
- Department of Pharmacotherapy, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
- *Correspondence: Toru Hosoi, ; Koichiro Ozawa,
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32
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The role of type 2 diabetes in neurodegeneration. Neurobiol Dis 2015; 84:22-38. [PMID: 25926349 DOI: 10.1016/j.nbd.2015.04.008] [Citation(s) in RCA: 185] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 04/18/2015] [Accepted: 04/21/2015] [Indexed: 02/07/2023] Open
Abstract
A growing body of evidence links type-2 diabetes (T2D) with dementia and neurodegenerative diseases such as Alzheimer's disease (AD). AD is the most common form of dementia and is characterised neuropathologically by the accumulation of extracellular beta amyloid (Aβ) peptide aggregates and intracellular hyper-phosphorylated tau protein, which are thought to drive and/or accelerate inflammatory and oxidative stress processes leading to neurodegeneration. Although the precise mechanism remains unclear, T2D can exacerbate these neurodegenerative processes. Brain atrophy, reduced cerebral glucose metabolism and CNS insulin resistance are features of both AD and T2D. Cell culture and animal studies have indicated that the early accumulation of Aβ may play a role in CNS insulin resistance and impaired insulin signalling. From the viewpoint of insulin resistance and impaired insulin signalling in the brain, these are also believed to initiate other aspects of brain injury, including inflammatory and oxidative stress processes. Here we review the clinical and experimental pieces of evidence that link these two chronic diseases of ageing, and discuss underlying mechanisms. The evaluation of treatments for the management of diabetes in preclinical, and clinical studies and trials for AD will also be discussed.
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Rojas JM, Bruinstroop E, Printz RL, Alijagic-Boers A, Foppen E, Turney MK, George L, Beck-Sickinger AG, Kalsbeek A, Niswender KD. Central nervous system neuropeptide Y regulates mediators of hepatic phospholipid remodeling and very low-density lipoprotein triglyceride secretion via sympathetic innervation. Mol Metab 2015; 4:210-21. [PMID: 25737956 PMCID: PMC4338317 DOI: 10.1016/j.molmet.2015.01.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 12/29/2014] [Accepted: 01/09/2015] [Indexed: 12/26/2022] Open
Abstract
OBJECTIVE Elevated very low-density lipoprotein (VLDL)-triglyceride (TG) secretion from the liver contributes to an atherogenic dyslipidemia that is associated with obesity, diabetes and the metabolic syndrome. Numerous models of obesity and diabetes are characterized by increased central nervous system (CNS) neuropeptide Y (NPY); in fact, a single intracerebroventricular (icv) administration of NPY in lean fasted rats elevates hepatic VLDL-TG secretion and does so, in large part, via signaling through the CNS NPY Y1 receptor. Thus, our overarching hypothesis is that elevated CNS NPY action contributes to dyslipidemia by activating central circuits that modulate liver lipid metabolism. METHODS Chow-fed Zucker fatty (ZF) rats were pair-fed by matching their caloric intake to that of lean controls and effects on body weight, plasma TG, and liver content of TG and phospholipid (PL) were compared to ad-libitum (ad-lib) fed ZF rats. Additionally, lean 4-h fasted rats with intact or disrupted hepatic sympathetic innervation were treated with icv NPY or NPY Y1 receptor agonist to identify novel hepatic mechanisms by which NPY promotes VLDL particle maturation and secretion. RESULTS Manipulation of plasma TG levels in obese ZF rats, through pair-feeding had no effect on liver TG content; however, hepatic PL content was substantially reduced and was tightly correlated with plasma TG levels. Treatment with icv NPY or a selective NPY Y1 receptor agonist in lean fasted rats robustly activated key hepatic regulatory proteins, stearoyl-CoA desaturase-1 (SCD-1), ADP-ribosylation factor-1 (ARF-1), and lipin-1, known to be involved in remodeling liver PL into TG for VLDL maturation and secretion. Lastly, we show that the effects of CNS NPY on key liporegulatory proteins are attenuated by hepatic sympathetic denervation. CONCLUSIONS These data support a model in which CNS NPY modulates mediators of hepatic PL remodeling and VLDL maturation to stimulate VLDL-TG secretion that is dependent on the Y1 receptor and sympathetic signaling to the liver.
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Key Words
- AGPAT, 1-acyl-glycerol-3-phosphate acyltransferase
- ARF-1, ADP-ribosylation factor-1
- ApoB, apolipoprotein B
- CNS, central nervous system
- Cyto, cytoplasmic
- DAG, diacylglycerol
- DGAT, diacylglycerol acyltransferase
- ER, endoplasmic reticulum
- FFA(s), free fatty acid(s)
- GAPDH, glyceraldehyde 3-phosphate dehydrogenase
- HDAC-1, histone deacetylase-1
- Lipin-1
- NE, norepinephrine
- NPY Y1 receptor
- NPY, neuropeptide Y
- Nuc, nuclear
- PA, phosphatidic acid
- PAP-1, phosphatidic acid phosphatase-1
- PF, pair-fed
- PL, phospholipid
- PLD, phospholipase D
- POMC, proopiomelanocortin
- Phospholipid
- RPL13A, ribosomal protein L13a
- RT-PCR, real-time PCR
- SCD-1, stearoyl-CoA desaturase-1
- SNS, sympathetic nervous system
- Sham, sham-denervation
- Sx, sympathetic denervation
- Sympathetic denervation
- TG, triglyceride
- Triglyceride
- VLDL
- VLDL, very low-density lipoprotein
- Veh, vehicle
- ZF, Zucker fatty
- ad-lib, ad-libitum
- icv, intracerebroventricular
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Affiliation(s)
- Jennifer M. Rojas
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Eveline Bruinstroop
- Department of Endocrinology and Metabolism, Laboratory of Endocrinology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Richard L. Printz
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Aldijana Alijagic-Boers
- Department of Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Science, Amsterdam, The Netherlands
| | - Ewout Foppen
- Department of Endocrinology and Metabolism, Laboratory of Endocrinology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Maxine K. Turney
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Leena George
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Annette G. Beck-Sickinger
- Institute of Biochemistry, Faculty of Bioscience, Pharmacy and Psychology, Leipzig University, Leipzig, Germany
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Laboratory of Endocrinology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Department of Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Science, Amsterdam, The Netherlands
| | - Kevin D. Niswender
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, United States
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, United States
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Tian JY, Tao RY, Zhang XL, Liu Q, He YB, Su YL, Ji TF, Ye F. Effect of Hypericum perforatum L. extract on insulin resistance and lipid metabolic disorder in high-fat-diet induced obese mice. Phytother Res 2014; 29:86-92. [PMID: 25266458 PMCID: PMC4303982 DOI: 10.1002/ptr.5230] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Revised: 08/07/2014] [Accepted: 08/30/2014] [Indexed: 11/17/2022]
Abstract
Natural product Hypericum perforatum L. has been used in folk medicine to improve mental performance. However, the effect of H. perforatum L. on metabolism is still unknown. In order to test whether H. perforatum L. extract (EHP) has an effect on metabolic syndrome, we treated diet induced obese (DIO) C57BL/6J mice with the extract. The chemical characters of EHP were investigated with thin-layer chromatography, ultraviolet, high-performance liquid chromatography (HPLC), and HPLC-mass spectrometry fingerprint analysis. Oral glucose tolerance test (OGTT), insulin tolerance test (ITT), and the glucose infusion rate (GIR) in hyperinsulinemic–euglycemic clamp test were performed to evaluate the glucose metabolism and insulin sensitivity. Skeletal muscle was examined for lipid metabolism. The results suggest that EHP can significantly improve the glucose and lipid metabolism in DIO mice. In vitro, EHP inhibited the catalytic activity of recombinant human protein tyrosine phosphatase 1B (PTP1B) and reduced the protein and mRNA levels of PTP1B in the skeletal muscle. Moreover, expressions of genes related to fatty acid uptake and oxidation were changed by EHP in the skeletal muscle. These results suggest that EHP may improve insulin resistance and lipid metabolism in DIO mice. © 2014 The Authors. Phytotherapy Research published by John Wiley & Sons Ltd.
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Affiliation(s)
- Jin-ying Tian
- Beijing Key Laboratory of New Drug Mechanisms and Pharmacological Evaluation Study, Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing, 100050, China
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Silva VRR, Micheletti TO, Pimentel GD, Katashima CK, Lenhare L, Morari J, Mendes MCS, Razolli DS, Rocha GZ, de Souza CT, Ryu D, Prada PO, Velloso LA, Carvalheira JBC, Pauli JR, Cintra DE, Ropelle ER. Hypothalamic S1P/S1PR1 axis controls energy homeostasis. Nat Commun 2014; 5:4859. [PMID: 25255053 DOI: 10.1038/ncomms5859] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 07/31/2014] [Indexed: 02/07/2023] Open
Abstract
Sphingosine 1-phosphate receptor 1 (S1PR1) is a G-protein-coupled receptor for sphingosine-1-phosphate (S1P) that has a role in many physiological and pathophysiological processes. Here we show that the S1P/S1PR1 signalling pathway in hypothalamic neurons regulates energy homeostasis in rodents. We demonstrate that S1PR1 protein is highly enriched in hypothalamic POMC neurons of rats. Intracerebroventricular injections of the bioactive lipid, S1P, reduce food consumption and increase rat energy expenditure through persistent activation of STAT3 and the melanocortin system. Similarly, the selective disruption of hypothalamic S1PR1 increases food intake and reduces the respiratory exchange ratio. We further show that STAT3 controls S1PR1 expression in neurons via a positive feedback mechanism. Interestingly, several models of obesity and cancer anorexia display an imbalance of hypothalamic S1P/S1PR1/STAT3 axis, whereas pharmacological intervention ameliorates these phenotypes. Taken together, our data demonstrate that the neuronal S1P/S1PR1/STAT3 signalling axis plays a critical role in the control of energy homeostasis in rats.
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Affiliation(s)
- Vagner R R Silva
- Laboratory of Molecular Biology of Exercise (LaBMEx). School of Applied Science, University of Campinas (UNICAMP), Rua Pedro Zaccarias, 1300, CEP 13484-350 Limeira, São Paulo, Brazil
| | - Thayana O Micheletti
- Faculty of Medical Sciences, Department of Internal Medicine, University of Campinas (UNICAMP), CEP 13083-887 Campinas, São Paulo, Brazil
| | - Gustavo D Pimentel
- Faculty of Medical Sciences, Department of Internal Medicine, University of Campinas (UNICAMP), CEP 13083-887 Campinas, São Paulo, Brazil
| | - Carlos K Katashima
- Faculty of Medical Sciences, Department of Internal Medicine, University of Campinas (UNICAMP), CEP 13083-887 Campinas, São Paulo, Brazil
| | - Luciene Lenhare
- Faculty of Medical Sciences, Department of Internal Medicine, University of Campinas (UNICAMP), CEP 13083-887 Campinas, São Paulo, Brazil
| | - Joseane Morari
- Laboratory of Cell Signalling, Faculty of Medical Sciences, University of Campinas (UNICAMP), CEP 13083-887 Campinas, São Paulo, Brazil
| | - Maria Carolina S Mendes
- Faculty of Medical Sciences, Department of Internal Medicine, University of Campinas (UNICAMP), CEP 13083-887 Campinas, São Paulo, Brazil
| | - Daniela S Razolli
- Laboratory of Cell Signalling, Faculty of Medical Sciences, University of Campinas (UNICAMP), CEP 13083-887 Campinas, São Paulo, Brazil
| | - Guilherme Z Rocha
- Faculty of Medical Sciences, Department of Internal Medicine, University of Campinas (UNICAMP), CEP 13083-887 Campinas, São Paulo, Brazil
| | - Claudio T de Souza
- Laboratory of Exercise Biochemistry and Physiology, Health Sciences Unit, University of Southern Santa Catarina, CEP 88806-000 Criciúma, Santa Catarina, Brazil
| | - Dongryeol Ryu
- Laboratory of Integrative and Systems Physiology, School of Life Sciences, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Patrícia O Prada
- Faculty of Medical Sciences, Department of Internal Medicine, University of Campinas (UNICAMP), CEP 13083-887 Campinas, São Paulo, Brazil
| | - Lício A Velloso
- Laboratory of Cell Signalling, Faculty of Medical Sciences, University of Campinas (UNICAMP), CEP 13083-887 Campinas, São Paulo, Brazil
| | - José B C Carvalheira
- Faculty of Medical Sciences, Department of Internal Medicine, University of Campinas (UNICAMP), CEP 13083-887 Campinas, São Paulo, Brazil
| | - José Rodrigo Pauli
- Laboratory of Molecular Biology of Exercise (LaBMEx). School of Applied Science, University of Campinas (UNICAMP), Rua Pedro Zaccarias, 1300, CEP 13484-350 Limeira, São Paulo, Brazil
| | - Dennys E Cintra
- 1] Laboratory of Molecular Biology of Exercise (LaBMEx). School of Applied Science, University of Campinas (UNICAMP), Rua Pedro Zaccarias, 1300, CEP 13484-350 Limeira, São Paulo, Brazil [2] Faculty of Medical Sciences, Department of Internal Medicine, University of Campinas (UNICAMP), CEP 13083-887 Campinas, São Paulo, Brazil [3] Laboratory of Cell Signalling, Faculty of Medical Sciences, University of Campinas (UNICAMP), CEP 13083-887 Campinas, São Paulo, Brazil
| | - Eduardo R Ropelle
- 1] Laboratory of Molecular Biology of Exercise (LaBMEx). School of Applied Science, University of Campinas (UNICAMP), Rua Pedro Zaccarias, 1300, CEP 13484-350 Limeira, São Paulo, Brazil [2] Faculty of Medical Sciences, Department of Internal Medicine, University of Campinas (UNICAMP), CEP 13083-887 Campinas, São Paulo, Brazil
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Chiappini F, Catalano KJ, Lee J, Peroni OD, Lynch J, Dhaneshwar AS, Wellenstein K, Sontheimer A, Neel BG, Kahn BB. Ventromedial hypothalamus-specific Ptpn1 deletion exacerbates diet-induced obesity in female mice. J Clin Invest 2014; 124:3781-92. [PMID: 25083988 DOI: 10.1172/jci68585] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 06/19/2014] [Indexed: 01/05/2023] Open
Abstract
Protein-tyrosine phosphatase 1B (PTP1B) regulates food intake (FI) and energy expenditure (EE) by inhibiting leptin signaling in the hypothalamus. In peripheral tissues, PTP1B regulates insulin signaling, but its effects on CNS insulin action are largely unknown. Mice harboring a whole-brain deletion of the gene encoding PTP1B (Ptpn1) are lean, leptin-hypersensitive, and resistant to high fat diet-induced (HFD-induced) obesity. Arcuate proopiomelanocortin (POMC) neuron-specific deletion of Ptpn1 causes a similar, but much milder, phenotype, suggesting that PTP1B also acts in other neurons to regulate metabolism. Steroidogenic factor-1-expressing (SF-1-expressing) neurons in the ventromedial hypothalamus (VMH) play an important role in regulating body weight, FI, and EE. Surprisingly, Ptpn1 deletion in SF-1 neurons caused an age-dependent increase in adiposity in HFD-fed female mice. Although leptin sensitivity was increased and FI was reduced in these mice, they had impaired sympathetic output and decreased EE. Immunohistochemical analysis showed enhanced leptin and insulin signaling in VMH neurons from mice lacking PTP1B in SF-1 neurons. Thus, in the VMH, leptin negatively regulates FI, promoting weight loss, whereas insulin suppresses EE, leading to weight gain. Our results establish a novel role for PTP1B in regulating insulin action in the VMH and suggest that increased insulin responsiveness in SF-1 neurons can overcome leptin hypersensitivity and enhance adiposity.
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Valsamakis G, Lois K, Kumar S, Mastorakos G. New molecular targets in the pathophysiology of obesity and available treatment options under investigation. Clin Obes 2014; 4:209-19. [PMID: 25826792 DOI: 10.1111/cob.12064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 05/12/2014] [Accepted: 05/14/2014] [Indexed: 12/22/2022]
Abstract
The pharmacotherapy of obesity has historically recorded an overall poor safety and efficacy profile largely because of the complex mechanisms involved in the pathophysiology of obesity. It is hoped that a better understanding of the regulation of body weight will lead us to the development of effective and safer drugs. Recent advances in our understanding of the regulation of energy homeostasis has allowed the design of novel anti-obesity drugs targeting specific molecules crucial for the modulation of energy balance, including drugs that induce satiety, modulate nutrient absorption or influence metabolism or lipogenesis. Almost a decade after the Food and Drug Administration approved the first weight loss medication, it recently approved two novel anti-obesity drugs Belviq (lorcaserin) and Qsymia (topiramate and phentermine), thus signalling the beginning of a new era in the pharmacotherapy of obesity. It is believed that the next generation of weight-loss drugs will be based on combination treatments with gut hormones in a manner that mimics the changes underlying surgically induced weight loss thus introducing the so called 'bariatric pharmacotherapy'. An in-depth understanding of the interrelated physiological and behavioural effects of these new molecules together with the development of new treatment paradigms is needed so that future disappointments in the field of obesity pharmacotherapy may be avoided.
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Affiliation(s)
- G Valsamakis
- Endocrine Unit, 2nd Department of Obs and Gynae, Areteeion University Hospital, Athens Medical School National and Kapodistrian University of Athens, Athens, Greece; WISDEM Centre for Diabetes, Endocrinology and Metabolism, Warwick Medical School, University of Warwick, Coventry, UK
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Abstract
A growing body of clinical and epidemiological research suggests that two of the most common diseases of aging, type 2 diabetes (T2DM) and Alzheimer disease (AD), are linked. The nature of the association is not known, but this observation has led to the notion that drugs developed for the treatment of T2DM may be beneficial in modifying the pathophysiology of AD and maintaining cognitive function. Recent advances in the understanding of the biology of T2DM have resulted in a growing number of therapies that are approved or in clinical development for this disease. This review summarizes the evidence that T2DM and AD are linked, with a focus on the cellular and molecular mechanisms in common, and then assesses the various clinical-stage diabetes drugs for their potential activity in AD. At a time when existing therapies for AD offer only limited symptomatic benefit for some patients, additional clinical trials of diabetes drugs are needed to at least advance the care of T2DM patients at risk for or with comorbid AD and also to determine their value for AD in general.
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Affiliation(s)
- Mark Yarchoan
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
| | - Steven E Arnold
- Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PADepartment of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
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39
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Pandey NR, Zhou X, Zaman T, Cruz SA, Qin Z, Lu M, Keyhanian K, Brunel JM, Stewart AF, Chen HH. LMO4 is required to maintain hypothalamic insulin signaling. Biochem Biophys Res Commun 2014; 450:666-72. [DOI: 10.1016/j.bbrc.2014.06.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 06/06/2014] [Indexed: 01/09/2023]
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Park SY, Gifford JR, Andtbacka RHI, Trinity JD, Hyngstrom JR, Garten RS, Diakos NA, Ives SJ, Dela F, Larsen S, Drakos S, Richardson RS. Cardiac, skeletal, and smooth muscle mitochondrial respiration: are all mitochondria created equal? Am J Physiol Heart Circ Physiol 2014; 307:H346-52. [PMID: 24906913 DOI: 10.1152/ajpheart.00227.2014] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Unlike cardiac and skeletal muscle, little is known about vascular smooth muscle mitochondrial respiration. Therefore, the present study examined mitochondrial respiratory rates in smooth muscle of healthy human feed arteries and compared with that of healthy cardiac and skeletal muscles. Cardiac, skeletal, and smooth muscles were harvested from a total of 22 subjects (53 ± 6 yr), and mitochondrial respiration was assessed in permeabilized fibers. Complex I + II, state 3 respiration, an index of oxidative phosphorylation capacity, fell progressively from cardiac to skeletal to smooth muscles (54 ± 1, 39 ± 4, and 15 ± 1 pmol·s(-1)·mg(-1), P < 0.05, respectively). Citrate synthase (CS) activity, an index of mitochondrial density, also fell progressively from cardiac to skeletal to smooth muscles (222 ± 13, 115 ± 2, and 48 ± 2 μmol·g(-1)·min(-1), P < 0.05, respectively). Thus, when respiration rates were normalized by CS (respiration per mitochondrial content), oxidative phosphorylation capacity was no longer different between the three muscle types. Interestingly, complex I state 2 normalized for CS activity, an index of nonphosphorylating respiration per mitochondrial content, increased progressively from cardiac to skeletal to smooth muscles, such that the respiratory control ratio, state 3/state 2 respiration, fell progressively from cardiac to skeletal to smooth muscles (5.3 ± 0.7, 3.2 ± 0.4, and 1.6 ± 0.3 pmol·s(-1)·mg(-1), P < 0.05, respectively). Thus, although oxidative phosphorylation capacity per mitochondrial content in cardiac, skeletal, and smooth muscles suggest all mitochondria are created equal, the contrasting respiratory control ratio and nonphosphorylating respiration highlight the existence of intrinsic functional differences between these muscle mitochondria. This likely influences the efficiency of oxidative phosphorylation and could potentially alter ROS production.
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Affiliation(s)
- Song-Young Park
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Jayson R Gifford
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Robert H I Andtbacka
- Department of Surgery, Huntsman Cancer Hospital, University of Utah, Salt Lake City, Utah
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah
| | - John R Hyngstrom
- Department of Surgery, Huntsman Cancer Hospital, University of Utah, Salt Lake City, Utah
| | - Ryan S Garten
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah
| | - Nikolaos A Diakos
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Utah, Salt Lake City, Utah
| | - Stephen J Ives
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; Health and Exercise Sciences Department, Skidmore College, Saratoga Springs, New York
| | - Flemming Dela
- Department of Biomedical Sciences, Copenhagen University, Copenhagen, Denmark; and
| | - Steen Larsen
- Department of Biomedical Sciences, Copenhagen University, Copenhagen, Denmark; and
| | - Stavros Drakos
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Utah, Salt Lake City, Utah
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah;
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41
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Pan H, Guo J, Su Z. Advances in understanding the interrelations between leptin resistance and obesity. Physiol Behav 2014; 130:157-69. [PMID: 24726399 DOI: 10.1016/j.physbeh.2014.04.003] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 03/07/2014] [Accepted: 04/02/2014] [Indexed: 02/09/2023]
Abstract
Obesity, which has developed into a global epidemic, is a risk factor in most chronic diseases and some forms of malignancy. The discovery of leptin in 1994 has opened a new field in obesity research. Currently, we know that leptin is the primary signal from energy stores and exerts negative feedback effects on energy intake. However, most individuals with diet-induced obesity (DIO) develop leptin resistance, which is characterized by elevated circulating leptin levels and decreased leptin sensitivity. To date, though various mechanisms have been proposed to explain leptin resistance, the exact mechanisms of leptin resistance in obesity are poorly understood. Consequently, it's an important issue worth discussing regarding what the exact interrelations between leptin resistance and obesity are. Here, we review the latest advancements in the molecular mechanisms of leptin resistance and the exact interrelations between leptin resistance, obesity, and obesity-related diseases, in order to supply new ideas for the study of obesity.
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Affiliation(s)
- Haitao Pan
- Key Research Center of Liver Regulation for Hyperlipidemia SATCM/Class III Laboratory of Metabolism SATCM, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou, Guangdong, China
| | - Jiao Guo
- Key Research Center of Liver Regulation for Hyperlipidemia SATCM/Class III Laboratory of Metabolism SATCM, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou, Guangdong, China.
| | - Zhengquan Su
- Key Research Center of Liver Regulation for Hyperlipidemia SATCM/Class III Laboratory of Metabolism SATCM, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou, Guangdong, China.
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Abstract
The insulin receptor (IR) is an important hub in insulin signaling and its activation is tightly regulated. Upon insulin stimulation, IR is activated through autophosphorylation, and consequently phosphorylates several insulin receptor substrate (IRS) proteins, including IRS1-6, Shc and Gab1. Certain adipokines have also been found to activate IR. On the contrary, PTP, Grb and SOCS proteins, which are responsible for the negative regulation of IR, are characterized as IR inhibitors. Additionally, many other proteins have been identified as IR substrates and participate in the insulin signaling pathway. To provide a more comprehensive understanding of the signals mediated through IR, we reviewed the upstream and downstream signal molecules of IR, summarized the positive and negative modulators of IR, and discussed the IR substrates and interacting adaptor proteins. We propose that the molecular events associated with IR should be integrated to obtain a better understanding of the insulin signaling pathway and diabetes.
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Affiliation(s)
- Yipeng Du
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
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43
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Crosstalk Between Insulin and Toll-like Receptor Signaling Pathways in the Central Nervous system. Mol Neurobiol 2014; 50:797-810. [DOI: 10.1007/s12035-013-8631-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 12/25/2013] [Indexed: 01/04/2023]
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Tsou RC, Rak KS, Zimmer DJ, Bence KK. Improved metabolic phenotype of hypothalamic PTP1B-deficiency is dependent upon the leptin receptor. Mol Metab 2014; 3:301-12. [PMID: 24749060 PMCID: PMC3986631 DOI: 10.1016/j.molmet.2014.01.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/05/2014] [Accepted: 01/11/2014] [Indexed: 12/14/2022] Open
Abstract
Protein tyrosine phosphatase 1B (PTP1B) is a known regulator of central metabolic signaling, and mice with whole brain-, leptin receptor (LepRb) expressing cell-, or proopiomelanocortin neuron-specific PTP1B-deficiency are lean, leptin hypersensitive, and display improved glucose homeostasis. However, whether the metabolic effects of central PTP1B-deficiency are due to action within the hypothalamus remains unclear. Moreover, whether or not these effects are exclusively due to enhanced leptin signaling is unknown. Here we report that mice with hypothalamic PTP1B-deficiency (Nkx2.1-PTP1B(-/-)) display decreased body weight and adiposity on high-fat diet with no associated improvements in glucose tolerance. Consistent with previous reports, we find that hypothalamic deletion of the LepRb in mice (Nkx2.1-LepRb(-/-)) results in extreme hyperphagia and obesity. Interestingly, deletion of hypothalamic PTP1B and LepRb (Nkx2.1-PTP1B(-/-):LepRb(-/-)) does not rescue the hyperphagia or obesity of Nkx2.1-LepRb(-/-) mice, suggesting that hypothalamic PTP1B contributes to the central control of energy balance through a leptin receptor-dependent pathway.
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Key Words
- BAT, Brown adipose tissue
- CNTF, Ciliary neurotrophic factor
- Cre, Cre recombinase
- GTT, Glucose tolerance test
- HFD, High-fat diet
- HPA, hypothalamus–pituitary–adrenal
- Hypothalamus
- IL-6, Interleukin-6
- ITT, Insulin tolerance test
- JAK2, Janus kinase 2
- LepRb, Leptin receptor long form
- Leptin
- Nkx2.1, NK2 homeobox 1 protein or thyroid transcription factor-1
- Obesity
- PI3K, Phosphatidylinositol 3-kinase
- POMC, Proopiomelanocortin
- PTP1B, Protein tyrosine phosphatase 1B
- PTPs, Protein tyrosine phosphatases
- Phosphatase
- Prdm16, PR domain containing 16
- SHP2, Src homology 2 domain-containing protein tyrosine phosphatase
- STAT3, Signal transducer and activator of transcription 3
- UCP1, Uncoupling protein 1
- WAT, White adipose tissue
- db/db, Leptin receptor-deficient mice
- ob/ob, leptin-deficient mice
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Affiliation(s)
- Ryan C Tsou
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kimberly S Rak
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Derek J Zimmer
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kendra K Bence
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Kubo M, Fukui M, Ito Y, Kitao T, Shirahase H, Hinoi E, Yoneda Y. Insulin Sensitization by a Novel Partial Peroxisome Proliferator-Activated Receptor γ Agonist With Protein Tyrosine Phosphatase 1B Inhibitory Activity in Experimental Osteoporotic Rats. J Pharmacol Sci 2014; 124:276-85. [DOI: 10.1254/jphs.13236fp] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Prada PO, Saad MJ. Tyrosine kinase inhibitors as novel drugs for the treatment of diabetes. Expert Opin Investig Drugs 2013; 22:751-63. [PMID: 23705634 DOI: 10.1517/13543784.2013.802768] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Some inhibitors of tyrosine kinase, as imatinib, erlotinib and sunitinib have antihyperglycemic effects but the mechanisms are not totally clear. AREAS COVERED It is well established that insulin resistance and beta-cell failure are hallmarks of type 2 diabetes mellitus (DM2). The present review will discuss the molecular mechanisms that account for insulin resistance and beta-cell failure in DM2, and also the effect of tyrosine kinase inhibitors in these processes. EXPERT OPINION A better understanding of how these drugs improve the two most important mechanisms of DM2 associated with suggestions of clinical studies will lead to improve the treatment of this disease.
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Affiliation(s)
- Patricia O Prada
- University of Campinas - UNICAMP, School of Applied Sciences, Limeira, SP, 13484-350, Brazil.
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The LIM domain only 4 protein is a metabolic responsive inhibitor of protein tyrosine phosphatase 1B that controls hypothalamic leptin signaling. J Neurosci 2013; 33:12647-55. [PMID: 23904601 DOI: 10.1523/jneurosci.0746-13.2013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Protein tyrosine phosphatase 1B (PTP1B) counteracts leptin signaling and is a therapeutic target for obesity and diabetes. Here we found that LIM domain only 4 (LMO4) inhibits PTP1B activity by increasing the oxidized inactive form of PTP1B. Mice with neuronal ablation of LMO4 have elevated PTP1B activity and impaired hypothalamic leptin signaling, and a PTP1B inhibitor normalized PTP1B activity and restored leptin control of circulating insulin levels. LMO4 is palmitoylated at its C-terminal cysteine, and deletion of this residue prevented palmitoylation and retention of LMO4 at the endoplasmic reticulum and abolished its inhibitory effect on PTP1B. Importantly, LMO4 palmitoylation is sensitive to metabolic stress; mice challenged with a brief high-fat diet or acute intracerebroventricular infusion of saturated fatty acid had less palmitoylated LMO4, less oxidized PTP1B, and increased PTP1B activity in the hypothalamus. Thus, unleashed PTP1B activity attributable to loss of LMO4 palmitoylation may account for rapid loss of central leptin signaling after acute exposure to saturated fat.
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48
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Ren H, Plum-Morschel L, Gutierrez-Juarez R, Lu TY, Kim-Muller JY, Heinrich G, Wardlaw SL, Silver R, Accili D. Blunted refeeding response and increased locomotor activity in mice lacking FoxO1 in synapsin-Cre-expressing neurons. Diabetes 2013; 62:3373-83. [PMID: 23835335 PMCID: PMC3781468 DOI: 10.2337/db13-0597] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Successful development of antiobesity agents requires detailed knowledge of neural pathways controlling body weight, eating behavior, and peripheral metabolism. Genetic ablation of FoxO1 in selected hypothalamic neurons decreases food intake, increases energy expenditure, and improves glucose homeostasis, highlighting the role of this gene in insulin and leptin signaling. However, little is known about potential effects of FoxO1 in other neurons. To address this question, we executed a broad-based neuronal ablation of FoxO1 using Synapsin promoter-driven Cre to delete floxed Foxo1 alleles. Lineage-tracing experiments showed that NPY/AgRP and POMC neurons were minimally affected by the knockout. Nonetheless, Syn-Cre-Foxo1 knockouts demonstrated a catabolic energy homeostatic phenotype with a blunted refeeding response, increased sensitivity to leptin and amino acid signaling, and increased locomotor activity, likely attributable to increased melanocortinergic tone. We confirmed these data in mice lacking the three Foxo genes. The effects on locomotor activity could be reversed by direct delivery of constitutively active FoxO1 to the mediobasal hypothalamus, but not to the suprachiasmatic nucleus. The data reveal that the integrative function of FoxO1 extends beyond the arcuate nucleus, suggesting that central nervous system inhibition of FoxO1 function can be leveraged to promote hormone sensitivity and prevent a positive energy balance.
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Chiarreotto-Ropelle EC, Pauli LSS, Katashima CK, Pimentel GD, Picardi PK, Silva VRR, de Souza CT, Prada PO, Cintra DE, Carvalheira JBC, Ropelle ER, Pauli JR. Acute exercise suppresses hypothalamic PTP1B protein level and improves insulin and leptin signaling in obese rats. Am J Physiol Endocrinol Metab 2013; 305:E649-59. [PMID: 23880311 DOI: 10.1152/ajpendo.00272.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hypothalamic inflammation is associated with insulin and leptin resistance, hyperphagia, and obesity. In this scenario, hypothalamic protein tyrosine phosphatase 1B (PTP1B) has emerged as the key phosphatase induced by inflammation that is responsible for the central insulin and leptin resistance. Here, we demonstrated that acute exercise reduced inflammation and PTP1B protein level/activity in the hypothalamus of obese rodents. Exercise disrupted the interaction between PTP1B with proteins involved in the early steps of insulin (IRβ and IRS-1) and leptin (JAK2) signaling, increased the tyrosine phosphorylation of these molecules, and restored the anorexigenic effects of insulin and leptin in obese rats. Interestingly, the anti-inflammatory action and the reduction of PTP1B activity mediated by exercise occurred in an interleukin-6 (IL-6)-dependent manner because exercise failed to reduce inflammation and PTP1B protein level after the disruption of hypothalamic-specific IL-6 action in obese rats. Conversely, intracerebroventricular administration of recombinant IL-6 reproduced the effects of exercise, improving hypothalamic insulin and leptin action by reducing the inflammatory signaling and PTP1B activity in obese rats at rest. Taken together, our study reports that physical exercise restores insulin and leptin signaling, at least in part, by reducing hypothalamic PTP1B protein level through the central anti-inflammatory response.
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50
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Pomytkin IA. H2O2 Signalling Pathway: A Possible Bridge between Insulin Receptor and Mitochondria. Curr Neuropharmacol 2013; 10:311-20. [PMID: 23730255 PMCID: PMC3520041 DOI: 10.2174/157015912804143559] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 06/07/2012] [Accepted: 06/24/2012] [Indexed: 01/20/2023] Open
Abstract
This review is focused on the mechanistic aspects of the insulin-induced H2O2 signalling pathway in neurons and the molecules affecting it, which act as risk factors for developing central insulin resistance. Insulin-induced H2O2 promotes insulin receptor activation and the mitochondria act as the insulin-sensitive H2O2 source, providing a direct molecular link between mitochondrial dysfunction and irregular insulin receptor activation. In this view, the accumulation of dysfunctional mitochondria during chronological ageing and Alzheimer's disease (AD) is a risk factor that may contribute to the development of dysfunctional cerebral insulin receptor signalling and insulin resistance. Due to the high significance of insulin-induced H2O2 for insulin receptor activation, oxidative stress-induced upregulation of antioxidant enzymes, e.g., in AD brains, may represent another risk factor contributing to the development of insulin resistance. As insulin-induced H2O2 signalling requires fully functional mitochondria, pharmacological strategies based on activating mitochondria biogenesis in the brain are central to the treatment of diseases associated with dysfunctional insulin receptor signalling in this organ.
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