1
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Smith KR, Wang W, Miller MR, Boucher M, Reynold JE, Daurio NA, Li D, Hirenallur-Shanthappa D, Ahn Y, Beebe DA, Kelly KL, Ross TT, Bence KK, Wan M. GPAT1 Deficiency in Mice Modulates NASH Progression in a Model-Dependent Manner. Cell Mol Gastroenterol Hepatol 2023; 17:279-291. [PMID: 37844795 PMCID: PMC10829521 DOI: 10.1016/j.jcmgh.2023.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/11/2023] [Accepted: 10/11/2023] [Indexed: 10/18/2023]
Abstract
BACKGROUND & AIMS Nonalcoholic fatty liver disease (NAFLD), and its more severe form, nonalcoholic steatohepatitis (NASH), is the leading cause for liver failure and liver cancer. Although the etiology is likely multifactorial, genes involved in regulating lipid metabolism are enriched in human NAFLD genome-wide association studies (GWAS), pointing to dysregulated lipid metabolism as a major pathogenic factor. Glycerol-3-phosphate acyltransferase 1 (GPAT1), encoded by GPAM, converts acyl-CoAs and glycerol-3-phosphate into lysophosphatidic acid and has been shown to regulate lipid accumulation in the liver. However, its role in mediating the progression from NAFLD to NASH has not been explored. METHODS GPAT1-deficient mice were generated and challenged with diets inducing hepatic steatosis and NASH. Effects of GPAT1 deficiency on lipid and systemic metabolic end points were evaluated. RESULTS Ablating GPAT1 globally or specifically in mouse hepatocytes reduced hepatic steatosis in the context of diet-induced or genetic obesity. Interestingly, blunting of progression from NAFLD to NASH in global GPAT1 knockout (KO) mice was model dependent. GPAT1 KO mice were protected from choline deficient, amino acid defined high-fat diet-induced NASH development, but not from the high fat, high carbohydrate, and high cholesterol diet-induced NASH. CONCLUSIONS Our preclinical data support the notion that lipid metabolism pathways regulated by GPAT1 in hepatocytes play an essential role in NASH progression, albeit in a model-dependent manner.
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Affiliation(s)
- Kathleen R Smith
- WRDM Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts
| | - Wenshan Wang
- WRDM Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts
| | - Melissa R Miller
- WRDM Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts
| | - Magalie Boucher
- WRDM Drug Safety, Research and Development, Pfizer Inc, Groton, Connecticut
| | - Jessica E Reynold
- WRDM Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts
| | - Natalie A Daurio
- WRDM Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts
| | - Dongmei Li
- WRDM Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts
| | | | - Youngwook Ahn
- WRDM Target Sciences, Pfizer Inc, Cambridge, Massachusetts
| | - David A Beebe
- WRDM Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts
| | - Kenneth L Kelly
- WRDM Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts
| | - Trenton T Ross
- WRDM Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts
| | - Kendra K Bence
- WRDM Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts
| | - Min Wan
- WRDM Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts.
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2
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Gart E, van Duyvenvoorde W, Snabel JM, de Ruiter C, Attema J, Caspers MPM, Lek S, van Heuven BJ, Speksnijder AGCL, Giera M, Menke A, Salic K, Bence KK, Tesz GJ, Keijer J, Kleemann R, Morrison MC. Translational characterization of the temporal dynamics of metabolic dysfunctions in liver, adipose tissue and the gut during diet-induced NASH development in Ldlr-/-.Leiden mice. Heliyon 2023; 9:e13985. [PMID: 36915476 PMCID: PMC10006542 DOI: 10.1016/j.heliyon.2023.e13985] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/17/2023] [Accepted: 02/17/2023] [Indexed: 03/06/2023] Open
Abstract
Background NAFLD progression, from steatosis to inflammation and fibrosis, results from an interplay of intra- and extrahepatic mechanisms. Disease drivers likely include signals from white adipose tissue (WAT) and gut. However, the temporal dynamics of disease development remain poorly understood. Methods High-fat-diet (HFD)-fed Ldlr-/-.Leiden mice were compared to chow-fed controls. At t = 0, 8, 16, 28 and 38w mice were euthanized, and liver, WAT depots and gut were analyzed biochemically, histologically and by lipidomics and transcriptomics together with circulating factors to investigate the sequence of pathogenic events and organ cross-talk during NAFLD development. Results HFD-induced obesity was associated with an increase in visceral fat, plasma lipids and hyperinsulinemia at t = 8w, along with increased liver steatosis and circulating liver damage biomarkers. In parallel, upstream regulator analysis predicted that lipid catabolism regulators were deactivated and lipid synthesis regulators were activated. Subsequently, hepatocyte hypertrophy, oxidative stress and hepatic inflammation developed. Hepatic collagen accumulated from t = 16 w and became pronounced at t = 28-38 w. Epididymal WAT was maximally hypertrophic from t = 8 w, which coincided with inflammation development. Mesenteric and subcutaneous WAT hypertrophy developed slower and did not appear to reach a maximum, with minimal inflammation. In gut, HFD significantly increased permeability, induced a shift in microbiota composition from t = 8 w and changed circulating gut-derived metabolites. Conclusion HFD-fed Ldlr-/-.Leiden mice develop obesity, dyslipidemia and insulin resistance, essentially as observed in obese NAFLD patients, underlining their translational value. We demonstrate that marked epididymal-WAT inflammation, and gut permeability and dysbiosis precede the development of NAFLD stressing the importance of a multiple-organ approach in the prevention and treatment of NAFLD.
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Affiliation(s)
- Eveline Gart
- Department of Metabolic Health Research, The Netherlands Organization for Applied Scientific Research (TNO), 2333 CK Leiden, the Netherlands.,Human and Animal Physiology, Wageningen University, 6708 WD Wageningen, the Netherlands
| | - Wim van Duyvenvoorde
- Department of Metabolic Health Research, The Netherlands Organization for Applied Scientific Research (TNO), 2333 CK Leiden, the Netherlands
| | - Jessica M Snabel
- Department of Metabolic Health Research, The Netherlands Organization for Applied Scientific Research (TNO), 2333 CK Leiden, the Netherlands
| | - Christa de Ruiter
- Department of Metabolic Health Research, The Netherlands Organization for Applied Scientific Research (TNO), 2333 CK Leiden, the Netherlands
| | - Joline Attema
- Department of Metabolic Health Research, The Netherlands Organization for Applied Scientific Research (TNO), 2333 CK Leiden, the Netherlands
| | - Martien P M Caspers
- Department of Microbiology and Systems Biology, The Netherlands Organization for Applied Scientific Research (TNO), Zeist, the Netherlands
| | - Serene Lek
- Clinnovate Health UK Ltd, Glasgow, United Kingdom
| | | | | | - Martin Giera
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, the Netherlands
| | - Aswin Menke
- Department of Metabolic Health Research, The Netherlands Organization for Applied Scientific Research (TNO), 2333 CK Leiden, the Netherlands
| | - Kanita Salic
- Department of Metabolic Health Research, The Netherlands Organization for Applied Scientific Research (TNO), 2333 CK Leiden, the Netherlands
| | - Kendra K Bence
- Pfizer Worldwide Research, Development & Medical, Internal Medicine Research Unit, Cambridge, MA, USA
| | - Gregory J Tesz
- Pfizer Worldwide Research, Development & Medical, Internal Medicine Research Unit, Cambridge, MA, USA
| | - Jaap Keijer
- Human and Animal Physiology, Wageningen University, 6708 WD Wageningen, the Netherlands
| | - Robert Kleemann
- Department of Metabolic Health Research, The Netherlands Organization for Applied Scientific Research (TNO), 2333 CK Leiden, the Netherlands
| | - Martine C Morrison
- Department of Metabolic Health Research, The Netherlands Organization for Applied Scientific Research (TNO), 2333 CK Leiden, the Netherlands
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3
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Loh K, Fukushima A, Zhang X, Galic S, Briggs D, Enriori PJ, Simonds S, Wiede F, Reichenbach A, Hauser C, Sims NA, Bence KK, Zhang S, Zhang ZY, Kahn BB, Neel BG, Andrews ZB, Cowley MA, Tiganis T. Elevated Hypothalamic TCPTP in Obesity Contributes to Cellular Leptin Resistance. Cell Metab 2022; 34:1892. [PMID: 36323237 PMCID: PMC9719734 DOI: 10.1016/j.cmet.2022.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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4
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Wang S, Zhu Q, Liang G, Franks T, Boucher M, Bence KK, Lu M, Castorena CM, Zhao S, Elmquist JK, Scherer PE, Horton JD. Response to Kunos et al. and Lotersztajn and Mallat. J Clin Invest 2022; 132:e156247. [PMID: 34981782 PMCID: PMC8718155 DOI: 10.1172/jci156247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
| | | | - Guosheng Liang
- Department of Internal Medicine and
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Tania Franks
- Drug Safety Research and Development, Pfizer Inc., Groton, Connecticut, and Cambridge, Massachusetts, USA
| | - Magalie Boucher
- Drug Safety Research and Development, Pfizer Inc., Groton, Connecticut, and Cambridge, Massachusetts, USA
| | - Kendra K. Bence
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts, USA
| | - Mingjian Lu
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts, USA
| | | | | | | | | | - Jay D. Horton
- Department of Internal Medicine and
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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5
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Wang S, Zhu Q, Liang G, Franks T, Boucher M, Bence KK, Lu M, Castorena CM, Zhao S, Elmquist JK, Scherer PE, Horton JD. Cannabinoid receptor-1 signaling in hepatocytes and stellate cells does not contribute to NAFLD. J Clin Invest 2021; 131:e152242. [PMID: 34499619 DOI: 10.1172/jci152242] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/31/2021] [Indexed: 11/17/2022] Open
Abstract
The endocannabinoid system regulates appetite and energy expenditure and inhibitors of the cannabinoid receptor-1 (CB-1) induce weight loss with improvement in components of the metabolic syndrome. While CB-1 blockage in brain is responsible for weight loss, many of the metabolic benefits associated with CB-1 blockade have been attributed to inhibition of CB-1 signaling in the periphery. As a result, there has been interest in developing a peripherally restricted CB-1 inhibitor for the treatment of nonalcoholic fatty liver disease (NAFLD) that would lack the unwanted centrally mediated side effects. Here, we produced mice that lacked CB-1 receptors in hepatocytes or stellate cells to determine if CB-1 signaling contributes to the development of NAFLD or liver fibrosis. Deletion of CB-1 receptors in hepatocytes did not alter the development of NAFLD in mice fed a high sucrose high fat diet or high fat diet (HFD). Similarly, deletion of CB-1 deletion specifically in stellate cells also did not prevent the development of NAFLD in mice fed the HFD nor did it protect mice for carbon tetrachloride (CCl4)-induced fibrosis. Combined, these studies do not support a direct role for hepatocyte or stellate cell CB-1 signaling in the development of NAFLD or liver fibrosis.
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Affiliation(s)
- Simeng Wang
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States of America
| | - Qingzhang Zhu
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States of America
| | - Guosheng Liang
- Department of Molecular Genetics, University of Texas Southwestern Medical Center at Dallas, Dallas, United States of America
| | - Tania Franks
- Drug Safety Research and Development, Pfizer Inc, Cambridge, United States of America
| | - Magalie Boucher
- Drug Safety Research and Development, Pfizer Inc, Cambridge, United States of America
| | - Kendra K Bence
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, United States of America
| | - Mingjian Lu
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, United States of America
| | - Carlos M Castorena
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States of America
| | - Shangang Zhao
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States of America
| | - Joel K Elmquist
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States of America
| | - Philipp E Scherer
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States of America
| | - Jay D Horton
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States of America
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6
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Abstract
BACKGROUND The incidence of non-alcoholic fatty liver disease (NAFLD) is rapidly increasing worldwide parallel to the global obesity epidemic. NAFLD encompasses a range of liver pathologies and most often originates from metabolically driven accumulation of fat in the liver, or non-alcoholic fatty liver (NAFL). In a subset of NAFL patients, the disease can progress to non-alcoholic steatohepatitis (NASH), which is a more severe form of liver disease characterized by hepatocyte injury, inflammation, and fibrosis. Significant progress has been made over the past decade in our understanding of NASH pathogenesis, but gaps remain in our mechanistic knowledge of the precise metabolic triggers for disease worsening. SCOPE OF REVIEW The transition from NAFL to NASH likely involves a complex constellation of multiple factors intrinsic and extrinsic to the liver. This review focuses on early metabolic events in the establishment of NAFL and initial stages of NASH. We discuss the association of NAFL with obesity as well as the role of adipose tissue in disease progression and highlight early metabolic drivers implicated in the pathological transition from hepatic fat accumulation to steatohepatitis. MAJOR CONCLUSIONS The close association of NAFL with features of metabolic syndrome highlight plausible mechanistic roles for adipose tissue health and the release of lipotoxic lipids, hepatic de novo lipogenesis (DNL), and disruption of the intestinal barrier in not only the initial establishment of hepatic steatosis, but also in mediating disease progression. Human genetic variants linked to NASH risk to date are heavily biased toward genes involved in the regulation of lipid metabolism, providing compelling support for the hypothesis that NASH is fundamentally a metabolic disease.
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Affiliation(s)
- Kendra K Bence
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA, USA.
| | - Morris J Birnbaum
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA, USA
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7
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Gutierrez JA, Liu W, Perez S, Xing G, Sonnenberg G, Kou K, Blatnik M, Allen R, Weng Y, Vera NB, Chidsey K, Bergman A, Somayaji V, Crowley C, Clasquin MF, Nigam A, Fulham MA, Erion DM, Ross TT, Esler WP, Magee TV, Pfefferkorn JA, Bence KK, Birnbaum MJ, Tesz GJ. Pharmacologic inhibition of ketohexokinase prevents fructose-induced metabolic dysfunction. Mol Metab 2021; 48:101196. [PMID: 33667726 PMCID: PMC8050029 DOI: 10.1016/j.molmet.2021.101196] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/21/2021] [Accepted: 02/23/2021] [Indexed: 02/07/2023] Open
Abstract
Objective Recent studies suggest that excess dietary fructose contributes to metabolic dysfunction by promoting insulin resistance, de novo lipogenesis (DNL), and hepatic steatosis, thereby increasing the risk of obesity, type 2 diabetes (T2D), non-alcoholic steatohepatitis (NASH), and related comorbidities. Whether this metabolic dysfunction is driven by the excess dietary calories contained in fructose or whether fructose catabolism itself is uniquely pathogenic remains controversial. We sought to test whether a small molecule inhibitor of the primary fructose metabolizing enzyme ketohexokinase (KHK) can ameliorate the metabolic effects of fructose. Methods The KHK inhibitor PF-06835919 was used to block fructose metabolism in primary hepatocytes and Sprague Dawley rats fed either a high-fructose diet (30% fructose kcal/g) or a diet reflecting the average macronutrient dietary content of an American diet (AD) (7.5% fructose kcal/g). The effects of fructose consumption and KHK inhibition on hepatic steatosis, insulin resistance, and hyperlipidemia were evaluated, along with the activation of DNL and the enzymes that regulate lipid synthesis. A metabolomic analysis was performed to confirm KHK inhibition and understand metabolite changes in response to fructose metabolism in vitro and in vivo. Additionally, the effects of administering a single ascending dose of PF-06835919 on fructose metabolism markers in healthy human study participants were assessed in a randomized placebo-controlled phase 1 study. Results Inhibition of KHK in rats prevented hyperinsulinemia and hypertriglyceridemia from fructose feeding. Supraphysiologic levels of dietary fructose were not necessary to cause metabolic dysfunction as rats fed the American diet developed hyperinsulinemia, hypertriglyceridemia, and hepatic steatosis, which were all reversed by KHK inhibition. Reversal of the metabolic effects of fructose coincided with reductions in DNL and inactivation of the lipogenic transcription factor carbohydrate response element-binding protein (ChREBP). We report that administering single oral doses of PF-06835919 was safe and well tolerated in healthy study participants and dose-dependently increased plasma fructose indicative of KHK inhibition. Conclusions Fructose consumption in rats promoted features of metabolic dysfunction seen in metabolic diseases such as T2D and NASH, including insulin resistance, hypertriglyceridemia, and hepatic steatosis, which were reversed by KHK inhibition. PF-06835919 is a potent inhibitor of fructose metabolism in rats and humans. Rats fed fructose at levels consistent with the typical American diet develop hyperinsulinemia, hyperlipidemia and steatosis. KHK inhibition reverses fructose-induced metabolic dysfunction by blocking ChREBP activation. Due to the global dietary prevalence of fructose, KHK inhibition is a potential pharmacotherapy for metabolic diseases.
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Affiliation(s)
- Jemy A Gutierrez
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Wei Liu
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Sylvie Perez
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Gang Xing
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Gabriele Sonnenberg
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Kou Kou
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Matt Blatnik
- Early Clinical Development, Pfizer Worldwide Research, Development, and Medical, Groton, CT 06340 USA
| | - Richard Allen
- Quantitative Systems Pharmacology, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Yan Weng
- Clinical Pharmacology, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Nicholas B Vera
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Kristin Chidsey
- Early Clinical Development, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Arthur Bergman
- Clinical Pharmacology, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Veena Somayaji
- Early Clinical Development, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Collin Crowley
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Michelle F Clasquin
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Anu Nigam
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Melissa A Fulham
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Derek M Erion
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Trenton T Ross
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - William P Esler
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Thomas V Magee
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Jeffrey A Pfefferkorn
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Kendra K Bence
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Morris J Birnbaum
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA
| | - Gregory J Tesz
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA 02139 USA.
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8
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Abstract
The abundance of dietary sweeteners and overconsumption of fructose are widely thought to promote metabolic disease. In this issue of Cell Metabolism, Andres-Hernando et al. (2020) identify the liver as the major site of fructose metabolism-mediated metabolic dysfunction and identify a surprising role for intestinal fructose metabolism in driving fructose intake.
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Affiliation(s)
- Gregory J Tesz
- Internal Medicine Research Unit, Pfizer Worldwide Research, Discovery and Medical, Cambridge, MA, USA
| | - Kendra K Bence
- Internal Medicine Research Unit, Pfizer Worldwide Research, Discovery and Medical, Cambridge, MA, USA.
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9
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Ross TT, Crowley C, Kelly KL, Rinaldi A, Beebe DA, Lech MP, Martinez RV, Carvajal-Gonzalez S, Boucher M, Hirenallur-Shanthappa D, Morin J, Opsahl AC, Vargas SR, Bence KK, Pfefferkorn JA, Esler WP. Acetyl-CoA Carboxylase Inhibition Improves Multiple Dimensions of NASH Pathogenesis in Model Systems. Cell Mol Gastroenterol Hepatol 2020; 10:829-851. [PMID: 32526482 PMCID: PMC7509217 DOI: 10.1016/j.jcmgh.2020.06.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 06/01/2020] [Accepted: 06/02/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Disordered metabolism, steatosis, hepatic inflammation, and fibrosis contribute to the pathogenesis of nonalcoholic steatohepatitis (NASH). Acetyl-CoA carboxylase (ACC) catalyzes the first committed step in de novo lipogenesis (DNL) and modulates mitochondrial fatty acid oxidation. Increased hepatic DNL flux and reduced fatty acid oxidation are hypothesized to contribute to steatosis. Some proinflammatory cells also show increased dependency on DNL, suggesting that ACC may regulate aspects of the inflammatory response in NASH. PF-05221304 is an orally bioavailable, liver-directed ACC1/2 inhibitor. The present studies sought to evaluate the effects of PF-05221304 on NASH pathogenic factors in experimental model systems. METHODS The effects of PF-05221304 on lipid metabolism, steatosis, inflammation, and fibrogenesis were investigated in both primary human-derived in vitro systems and in vivo rodent models. RESULTS PF-05221304 inhibited DNL, stimulated fatty acid oxidation, and reduced triglyceride accumulation in primary human hepatocytes, and reduced DNL and steatosis in Western diet-fed rats in vivo, showing the potential to reduce hepatic lipid accumulation and potentially lipotoxicity. PF-05221304 blocked polarization of human T cells to proinflammatory but not anti-inflammatory T cells, and suppressed activation of primary human stellate cells to myofibroblasts in vitro, showing direct effects on inflammation and fibrogenesis. Consistent with these observations, PF-05221304 also reduced markers of inflammation and fibrosis in the diethylnitrosamine chemical-induced liver injury model and the choline-deficient, high-fat-fed rat model. CONCLUSIONS The liver-directed dual ACC1/ACC2 inhibitor directly improved multiple nonalcoholic fatty liver disease/NASH pathogenic factors including steatosis, inflammation, and fibrosis in both human-derived in vitro systems and rat models.
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Affiliation(s)
- Trenton T. Ross
- Internal Medicine Research Unit, Pfizer Worldwide Research and Development, Cambridge Massachusetts
| | - Collin Crowley
- Internal Medicine Research Unit, Pfizer Worldwide Research and Development, Cambridge Massachusetts
| | - Kenneth L. Kelly
- Internal Medicine Research Unit, Pfizer Worldwide Research and Development, Cambridge Massachusetts
| | - Anthony Rinaldi
- Internal Medicine Research Unit, Pfizer Worldwide Research and Development, Cambridge Massachusetts
| | - David A. Beebe
- Internal Medicine Research Unit, Pfizer Worldwide Research and Development, Cambridge Massachusetts
| | - Matthew P. Lech
- Inflammation and Immunology Research Unit, Pfizer Worldwide Research and Development, Cambridge Massachusetts
| | - Robert V. Martinez
- Inflammation and Immunology Research Unit, Pfizer Worldwide Research and Development, Cambridge Massachusetts
| | | | - Magalie Boucher
- Drug Safety Research and Development, Pfizer Worldwide Research and Development, Cambridge Massachusetts
| | | | - Jeffrey Morin
- Comparative Medicine, Pfizer Worldwide Research and Development, Cambridge Massachusetts
| | - Alan C. Opsahl
- Drug Safety Research and Development, Pfizer Worldwide Research and Development, Cambridge Massachusetts
| | - Sarah R. Vargas
- Drug Safety Research and Development, Pfizer Worldwide Research and Development, Cambridge Massachusetts
| | - Kendra K. Bence
- Internal Medicine Research Unit, Pfizer Worldwide Research and Development, Cambridge Massachusetts
| | - Jeffrey A. Pfefferkorn
- Internal Medicine Research Unit, Pfizer Worldwide Research and Development, Cambridge Massachusetts
| | - William P. Esler
- Internal Medicine Research Unit, Pfizer Worldwide Research and Development, Cambridge Massachusetts,Correspondence Address correspondence to: William P. Esler, PhD, Internal Medicine Research Unit, Pfizer, Inc, 1 Portland Street, Cambridge, Massachusetts 02139.
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10
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Abstract
The prevalence and diagnosis of nonalcoholic fatty liver disease (NAFLD) is on the rise worldwide and currently has no FDA-approved pharmacotherapy. The increase in disease burden of NAFLD and a more severe form of this progressive liver disease, nonalcoholic steatohepatitis (NASH), largely mirrors the increase in obesity and type 2 diabetes (T2D) and reflects the hepatic manifestation of an altered metabolic state. Indeed, metabolic syndrome, defined as a constellation of obesity, insulin resistance, hyperglycemia, dyslipidemia and hypertension, is the major risk factor predisposing the NAFLD and NASH. There are multiple potential pharmacologic strategies to rebalance aspects of disordered metabolism in NAFLD. These include therapies aimed at reducing hepatic steatosis by directly modulating lipid metabolism within the liver, inhibiting fructose metabolism, altering delivery of free fatty acids from the adipose to the liver by targeting insulin resistance and/or adipose metabolism, modulating glycemia, and altering pleiotropic metabolic pathways simultaneously. Emerging data from human genetics also supports a role for metabolic drivers in NAFLD and risk for progression to NASH. In this review, we highlight the prominent metabolic drivers of NAFLD pathogenesis and discuss the major metabolic targets of NASH pharmacotherapy.
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Key Words
- acc, acetyl-coa carboxylase
- alt, alanine aminotransferase
- aso, anti-sense oligonucleotide
- ast, aspartate aminotransferase
- chrebp, carbohydrate response element binding protein
- ci, confidence interval
- dgat, diacylglycerol o-acyltransferase
- dnl, de novo lipogenesis
- fas, fatty acid synthase
- ffa, free fatty acid
- fgf, fibroblast growth factor
- fxr, farnesoid x receptor
- glp-1, glucagon-like peptide-1
- hdl, high-density lipoprotein
- homa-ir, homeostatic model assessment of insulin resistance
- ldl, low-density lipoprotein
- nafld, nonalcoholic fatty liver disease
- nas, nonalcoholic fatty liver disease activity score
- nash, nonalcoholic steatohepatitis
- or, odds ratio
- pdff, proton density fat fraction
- ppar, peroxisome proliferator-activated receptor
- sglt2, sodium glucose co-transporter 2
- srebp-1c, sterol regulatory element binding protein-1c
- t2d, type 2 diabetes
- t2dm, type 2 diabetes mellitus
- tg, triglyceride
- th, thyroid hormone
- thr, thyroid hormone receptor
- treg, regulatory t cells
- tzd, thiazolidinedione
- vldl, very low-density lipoprotein
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Affiliation(s)
- William P Esler
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts
| | - Kendra K Bence
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts.
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Le Sommer S, Morrice N, Pesaresi M, Thompson D, Vickers MA, Murray GI, Mody N, Neel BG, Bence KK, Wilson HM, Delibegović M. Deficiency in Protein Tyrosine Phosphatase PTP1B Shortens Lifespan and Leads to Development of Acute Leukemia. Cancer Res 2017; 78:75-87. [PMID: 29122767 DOI: 10.1158/0008-5472.can-17-0946] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/29/2017] [Accepted: 10/25/2017] [Indexed: 01/05/2023]
Abstract
Protein tyrosine phosphatase PTP1B is a critical regulator of signaling pathways controlling metabolic homeostasis, cell proliferation, and immunity. In this study, we report that global or myeloid-specific deficiency of PTP1B in mice decreases lifespan. We demonstrate that myeloid-specific deficiency of PTP1B is sufficient to promote the development of acute myeloid leukemia. LysM-PTP1B-/- mice lacking PTP1B in the innate myeloid cell lineage displayed a dysregulation of bone marrow cells with a rapid decline in population at midlife and a concomitant increase in peripheral blood blast cells. This phenotype manifested further with extramedullary tumors, hepatic macrophage infiltration, and metabolic reprogramming, suggesting increased hepatic lipid metabolism prior to overt tumor development. Mechanistic investigations revealed an increase in anti-inflammatory M2 macrophage responses in liver and spleen, as associated with increased expression of arginase I and the cytokines IL10 and IL4. We also documented STAT3 hypersphosphorylation and signaling along with JAK-dependent upregulation of antiapoptotic proteins Bcl2 and BclXL. Our results establish a tumor suppressor role for PTP1B in the myeloid lineage cells, with evidence that its genetic inactivation in mice is sufficient to drive acute myeloid leukemia.Significance: This study defines a tumor suppressor function for the protein tyrosine phosphatase PTP1B in myeloid lineage cells, with evidence that its genetic inactivation in mice is sufficient to drive acute myeloid leukemia. Cancer Res; 78(1); 75-87. ©2017 AACR.
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Affiliation(s)
| | - Nicola Morrice
- Institute of Medical Sciences, University of Aberdeen, United Kingdom
| | - Martina Pesaresi
- Institute of Medical Sciences, University of Aberdeen, United Kingdom
| | - Dawn Thompson
- Institute of Medical Sciences, University of Aberdeen, United Kingdom
| | - Mark A Vickers
- Institute of Medical Sciences, University of Aberdeen, United Kingdom
| | - Graeme I Murray
- Institute of Medical Sciences, University of Aberdeen, United Kingdom
| | - Nimesh Mody
- Institute of Medical Sciences, University of Aberdeen, United Kingdom
| | - Benjamin G Neel
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Medical Center, New York University, New York, New York
| | - Kendra K Bence
- Department of Biomedical Sciences, University of Pennsylvania School of Veterinary Medicine, Philadelphia
| | - Heather M Wilson
- Institute of Medical Sciences, University of Aberdeen, United Kingdom.
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Jobe F, Patel B, Kuzmanovic T, Makishima H, Yang Y, Przychodzen B, Hutchison RE, Bence KK, Maciejewski JP, Mohi G. Deletion of Ptpn1 induces myeloproliferative neoplasm. Leukemia 2017; 31:1229-1234. [PMID: 28111468 DOI: 10.1038/leu.2017.31] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- F Jobe
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - B Patel
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - T Kuzmanovic
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - H Makishima
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Y Yang
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - B Przychodzen
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - R E Hutchison
- Department of Pathology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - K K Bence
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - J P Maciejewski
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - G Mohi
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY, USA
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Hayes MR, Skibicka KP, Leichner TM, Guarnieri DJ, DiLeone RJ, Bence KK, Grill HJ. Endogenous Leptin Signaling in the Caudal Nucleus Tractus Solitarius and Area Postrema Is Required for Energy Balance Regulation. Cell Metab 2016; 23:744. [PMID: 27076082 DOI: 10.1016/j.cmet.2016.02.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Hayes MR, Leichner TM, Zhao S, Lee GS, Chowansky A, Zimmer D, De Jonghe BC, Kanoski SE, Grill HJ, Bence KK. Intracellular Signals Mediating the Food Intake-Suppressive Effects of Hindbrain Glucagon-like Peptide-1 Receptor Activation. Cell Metab 2016; 23:745. [PMID: 27076083 DOI: 10.1016/j.cmet.2016.02.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Bruder-Nascimento T, Butler BR, Herren DJ, Brands MW, Bence KK, Belin de Chantemèle EJ. Deletion of protein tyrosine phosphatase 1b in proopiomelanocortin neurons reduces neurogenic control of blood pressure and protects mice from leptin- and sympatho-mediated hypertension. Pharmacol Res 2015; 102:235-44. [PMID: 26523876 DOI: 10.1016/j.phrs.2015.10.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 10/14/2015] [Accepted: 10/14/2015] [Indexed: 12/15/2022]
Abstract
Protein tyrosine phosphatase 1b (Ptp1b), which represses leptin signaling, is a promising therapeutic target for obesity. Genome wide deletion of Ptp1b, increases leptin sensitivity, protects mice from obesity and diabetes, but alters cardiovascular function by increasing blood pressure (BP). Leptin-control of metabolism is centrally mediated and involves proopiomelanocortin (POMC) neurons. Whether these neurons contribute to leptin-mediated increases in BP remain unclear. We hypothesized that increasing leptin signaling in POMC neurons with Ptp1b deletion will sensitize the cardiovascular system to leptin and enhance neurogenic control of BP. We analyzed the cardiovascular phenotype of Ptp1b+/+ and POMC-Ptp1b-/- mice, at baseline and after 7 days of leptin infusion or sympatho-activation with phenylephrine. POMCPtp1b deletion did not alter baseline cardiovascular hemodynamics (BP, heart rate) but reduced BP response to ganglionic blockade and plasma catecholamine levels that suggests a decreased neurogenic control of BP. In contrast, POMC-Ptp1b deletion increased vascular adrenergic reactivity and aortic α-adrenergic receptors expression. Chronic leptin treatment reduced vascular adrenergic reactivity and blunted diastolic and mean BP increases in POMC-Ptp1b-/- mice only. Similarly POMC-Ptp1b-/- mice exhibited a blunted increased in diastolic and mean BP accompanied by a gradual reduction in adrenergic reactivity in response to chronic vascular sympatho-activation with phenylephrine. Together these data rule out our hypothesis but suggest that deletion of Ptp1b in POMC neurons protects from leptin- and sympatho-mediated increases in BP. Vascular adrenergic desensitization appears as a protective mechanism against hypertension, and POMC-Ptp1b as a key therapeutic target for the treatment of metabolic and cardiovascular dysfunctions associated with obesity.
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Affiliation(s)
- Thiago Bruder-Nascimento
- Department of Physiology, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States
| | - Benjamin R Butler
- Department of Physiology, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States
| | - David J Herren
- Department of Physiology, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States
| | - Michael W Brands
- Department of Physiology, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States
| | - Kendra K Bence
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Eric J Belin de Chantemèle
- Department of Physiology, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States.
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16
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Ozek C, Zimmer DJ, De Jonghe BC, Kalb RG, Bence KK. Ablation of intact hypothalamic and/or hindbrain TrkB signaling leads to perturbations in energy balance. Mol Metab 2015; 4:867-80. [PMID: 26629410 PMCID: PMC4632115 DOI: 10.1016/j.molmet.2015.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 08/10/2015] [Accepted: 08/11/2015] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE Brain-derived neurotrophic factor (BDNF) and its receptor, tropomyosin receptor kinase B (TrkB), play a paramount role in the central regulation of energy balance. Despite the substantial body of genetic evidence implicating BDNF- or TrkB-deficiency in human obesity, the critical brain region(s) contributing to the endogenous role of BDNF/TrkB signaling in metabolic control remain unknown. METHODS We assessed the importance of intact hypothalamic or hindbrain TrkB signaling in central regulation of energy balance by generating Nkx2.1-Ntrk2-/- and Phox2b-Ntrk2+/- mice, respectively, and comparing metabolic parameters (body weight, adiposity, food intake, energy expenditure and glucose homeostasis) under high-fat diet or chow fed conditions. RESULTS Our data show that when fed a high-fat diet, male and female Nkx2.1-Ntrk2-/- mice have significantly increased body weight and adiposity that is likely driven by reduced locomotor activity and core body temperature. When maintained on a chow diet, female Nkx2.1-Ntrk2-/- mice exhibit an increased body weight and adiposity phenotype more robust than in males, which is accompanied by hyperphagia that precedes the onset of a body weight difference. In addition, under both diet conditions, Nkx2.1-Ntrk2-/- mice show increased blood glucose, serum insulin and leptin levels. Mice with complete hindbrain TrkB-deficiency (Phox2b-Ntrk2-/-) are perinatal lethal, potentially indicating a vital role for TrkB in visceral motor neurons that control cardiovascular, respiratory, and digestive functions during development. Phox2b-Ntrk2+/- heterozygous mice are similar in body weight, adiposity and glucose homeostasis parameters compared to wild type littermate controls when maintained on a high-fat or chow diet. Interestingly, despite the absence of a body weight difference, Phox2b-Ntrk2+/- heterozygous mice exhibit pronounced hyperphagia. CONCLUSION Taken together, our findings suggest that the hypothalamus is a key brain region involved in endogenous BDNF/TrkB signaling and central metabolic control and that endogenous hindbrain TrkB likely plays a role in modulating food intake and survival of mice. Our findings also show that female mice lacking TrkB in the hypothalamus have a more robust metabolic phenotype.
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Key Words
- Agrp, agouti-related peptide
- BAT, brown adipose tissue
- BDNF
- BDNF, brain-derived neurotrophic factor
- Cidea, cell death-inducing DFFA-like effector a
- Cre, Cre recombinase
- DVC, dorsal vagal complex
- Elovl3, elongation of very long fatty acids-like 3
- GTT, glucose tolerance test
- HFD, high-fat diet
- HPA axis, hypothalamic-pituitary-adrenal axis
- Hindbrain
- Hypothalamus
- LepR, leptin receptor
- Mc4R, melanocortin 4 receptor
- NTS, nucleus of the solitary tract
- Nkx2.1, Nk2 homeobox 1 protein
- Npy, neuropeptide Y
- Obesity
- PVH, paraventricular nucleus of the hypothalamus
- Pgc1α, peroxisome proliferator-activated receptor gamma coactivator 1 alpha
- Phox2b, paired-like homeobox 2b protein
- Pomc, pro-opiomelanocortin
- Pparγ, peroxisome proliferator-activated receptor gamma
- Prdm16, PR domain containing 16
- TrkB
- TrkB, tropomyosin receptor kinase B
- Ucp1, uncoupling protein 1
- VMH, ventromedial nucleus of the hypothalamus
- eWAT, epididymal white adipose tissue
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Affiliation(s)
- Ceren Ozek
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Derek J Zimmer
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Bart C De Jonghe
- Department of Biobehavioral Health Sciences, School of Nursing, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Robert G Kalb
- Department of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Kendra K Bence
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
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17
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Dodd GT, Decherf S, Loh K, Simonds SE, Wiede F, Balland E, Merry TL, Münzberg H, Zhang ZY, Kahn BB, Neel BG, Bence KK, Andrews ZB, Cowley MA, Tiganis T. Leptin and insulin act on POMC neurons to promote the browning of white fat. Cell 2015; 160:88-104. [PMID: 25594176 DOI: 10.1016/j.cell.2014.12.022] [Citation(s) in RCA: 266] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 10/14/2014] [Accepted: 12/10/2014] [Indexed: 01/06/2023]
Abstract
The primary task of white adipose tissue (WAT) is the storage of lipids. However, "beige" adipocytes also exist in WAT. Beige adipocytes burn fat and dissipate the energy as heat, but their abundance is diminished in obesity. Stimulating beige adipocyte development, or WAT browning, increases energy expenditure and holds potential for combating metabolic disease and obesity. Here, we report that insulin and leptin act together on hypothalamic neurons to promote WAT browning and weight loss. Deletion of the phosphatases PTP1B and TCPTP enhanced insulin and leptin signaling in proopiomelanocortin neurons and prevented diet-induced obesity by increasing WAT browning and energy expenditure. The coinfusion of insulin plus leptin into the CNS or the activation of proopiomelanocortin neurons also increased WAT browning and decreased adiposity. Our findings identify a homeostatic mechanism for coordinating the status of energy stores, as relayed by insulin and leptin, with the central control of WAT browning.
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Affiliation(s)
- Garron T Dodd
- Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Stephanie Decherf
- Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Kim Loh
- Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | | | - Florian Wiede
- Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Eglantine Balland
- Department of Physiology, Monash University, Victoria 3800, Australia
| | - Troy L Merry
- Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Heike Münzberg
- Pennington Biomedical Research Center, LSU Systems, Baton Rouge, LA 70808, USA
| | - Zhong-Yin Zhang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Barbara B Kahn
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Benjamin G Neel
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Hospital and Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 2M9, Canada
| | - Kendra K Bence
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Zane B Andrews
- Department of Physiology, Monash University, Victoria 3800, Australia
| | - Michael A Cowley
- Department of Physiology, Monash University, Victoria 3800, Australia
| | - Tony Tiganis
- Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia.
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Ozek C, Kanoski SE, Zhang ZY, Grill HJ, Bence KK. Protein-tyrosine phosphatase 1B (PTP1B) is a novel regulator of central brain-derived neurotrophic factor and tropomyosin receptor kinase B (TrkB) signaling. J Biol Chem 2014; 289:31682-31692. [PMID: 25288805 DOI: 10.1074/jbc.m114.603621] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Neuronal protein-tyrosine phosphatase 1B (PTP1B) deficiency in mice results in enhanced leptin signaling and protection from diet-induced obesity; however, whether additional signaling pathways in the brain contribute to the metabolic effects of PTP1B deficiency remains unclear. Here, we show that the tropomyosin receptor kinase B (TrkB) receptor is a direct PTP1B substrate and implicate PTP1B in the regulation of the central brain-derived neurotrophic factor (BDNF) signaling. PTP1B interacts with activated TrkB receptor in mouse brain and human SH-SY5Y neuroblastoma cells. PTP1B overexpression reduces TrkB phosphorylation and activation of downstream signaling pathways, whereas PTP1B inhibition augments TrkB signaling. Notably, brains of Ptpn1(-/-) mice exhibit enhanced TrkB phosphorylation, and Ptpn1(-/-) mice are hypersensitive to central BDNF-induced increase in core temperature. Taken together, our findings demonstrate that PTP1B is a novel physiological regulator of TrkB and that enhanced BDNF/TrkB signaling may contribute to the beneficial metabolic effects of PTP1B deficiency.
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Affiliation(s)
- Ceren Ozek
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Scott E Kanoski
- Department of Biological Sciences, Human and Evolutionary Biology Section, University of Southern California, Los Angeles, California 90089, and
| | - Zhong-Yin Zhang
- Department of Biochemistry and Molecular Biology, School of Medicine, Indiana University, Indianapolis, Indiana 46202
| | - Harvey J Grill
- Department of Psychology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Kendra K Bence
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104,.
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Lim MA, Bence KK, Sandesara I, Andreux P, Auwerx J, Ishibashi J, Seale P, Kalb RG. Genetically altering organismal metabolism by leptin-deficiency benefits a mouse model of amyotrophic lateral sclerosis. Hum Mol Genet 2014; 23:4995-5008. [PMID: 24833719 DOI: 10.1093/hmg/ddu214] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal, neurodegenerative disease that causes death of motor neurons. ALS patients and mouse models of familial ALS display organismal level metabolic dysfunction, which includes increased energy expenditure despite decreased lean mass. The pathophysiological relevance of abnormal energy homeostasis to motor neuron disease remains unclear. Leptin is an adipocyte-derived hormone that regulates whole-animal energy expenditure. Here, we report that placing mutant superoxide dismutase 1 (SOD1) mice in a leptin-deficient background improves energy homeostasis and slows disease progression. Leptin-deficient mutant SOD1 mice possess increased bodyweight and fat mass, as well as decreased energy expenditure. These observations coincide with enhanced survival, improved strength and decreased motor neuron loss. These results suggest that altering whole-body energy metabolism in mutant SOD1 mice can mitigate disease progression. We propose that manipulations that increase fat mass and reduce energy expenditure will be beneficial in the setting of motor neuron disease.
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Affiliation(s)
- Maria A Lim
- Division of Neurology, Department of Pediatrics, Research Institute, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA, Neuroscience Graduate Group
| | - Kendra K Bence
- Neuroscience Graduate Group, Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ishani Sandesara
- Division of Neurology, Department of Pediatrics, Research Institute, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Pénélope Andreux
- Laboratory for Integrative and Systems Physiology, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Johan Auwerx
- Laboratory for Integrative and Systems Physiology, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Jeff Ishibashi
- Institute for Diabetes, Obesity and Metabolism, Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Patrick Seale
- Institute for Diabetes, Obesity and Metabolism, Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert G Kalb
- Division of Neurology, Department of Pediatrics, Research Institute, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA, Neuroscience Graduate Group, Department of Neurology and
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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] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 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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Owen C, Lees EK, Grant L, Zimmer DJ, Mody N, Bence KK, Delibegović M. Inducible liver-specific knockdown of protein tyrosine phosphatase 1B improves glucose and lipid homeostasis in adult mice. Diabetologia 2013; 56:2286-96. [PMID: 23832083 DOI: 10.1007/s00125-013-2992-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 06/14/2013] [Indexed: 12/19/2022]
Abstract
AIMS/HYPOTHESIS Protein tyrosine phosphatase 1B (PTP1B) is a key negative regulator of insulin signalling. Hepatic PTP1B deficiency, using the Alb-Cre promoter to drive Ptp1b deletion from birth in mice, improves glucose homeostasis, insulin sensitivity and lipid metabolism. The aim of this study was to investigate the therapeutic potential of decreasing liver PTP1B levels in obese and insulin-resistant adult mice. METHODS Inducible Ptp1b liver-specific knockout mice were generated using SA-Cre-ER(T2) mice crossed with Ptp1b floxed (Ptp1b(fl/fl)) mice. Mice were fed a high-fat diet (HFD) for 12 weeks to induce obesity and insulin resistance. Tamoxifen was administered in the HFD to induce liver-specific deletion of Ptp1b (SA-Ptp1b(-/-) mice). Body weight, glucose homeostasis, lipid homeostasis, serum adipokines, insulin signalling and endoplasmic reticulum (ER) stress were examined. RESULTS Despite no significant change in body weight relative to HFD-fed Ptp1b(fl/fl) control mice, HFD-fed SA-Ptp1b(-/-) mice exhibited a reversal of glucose intolerance as determined by improved glucose and pyruvate tolerance tests, decreased fed and fasting blood glucose and insulin levels, lower HOMA of insulin resistance, circulating leptin, serum and liver triacylglycerols, serum NEFA and decreased HFD-induced ER stress. This was associated with decreased glycogen synthase, eukaryotic translation initiation factor-2α kinase 3, eukaryotic initiation factor 2α and c-Jun NH2-terminal kinase 2 phosphorylation, and decreased expression of Pepck. CONCLUSIONS/INTERPRETATION Inducible liver-specific PTP1B knockdown reverses glucose intolerance and improves lipid homeostasis in HFD-fed obese and insulin-resistant adult mice. This suggests that knockdown of liver PTP1B in individuals who are already obese/insulin resistant may have relatively rapid, beneficial therapeutic effects.
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Affiliation(s)
- C Owen
- Institute of Medical Sciences, School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
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22
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Abstract
Protein tyrosine phosphatases (PTPs) are important regulators of intracellular signaling pathways via the dephosphorylation of phosphotyrosyl residues on various receptor and non-receptor substrates. The phosphorylation state of central nervous system (CNS) signaling components underlies the molecular mechanisms of a variety of physiological functions including the control of energy balance and glucose homeostasis. In this review, we summarize the current evidence implicating PTPs as central regulators of metabolism, specifically highlighting their interactions with the neuronal leptin and insulin signaling pathways. We discuss the role of a number of PTPs (PTP1B, SHP2, TCPTP, RPTPe, and PTEN), reviewing the findings from genetic mouse models and in vitro studies which highlight these phosphatases as key central regulators of energy homeostasis.
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Affiliation(s)
- Ryan C Tsou
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania Philadelphia, PA, USA
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Belin de Chantemele EJ, Bence KK, Hill LK. Abstract 23: Increasing Leptin Sensitivity in Proopiomelanocortin Neurons Does not Sensitize the Cardiovascular System to Leptin. Hypertension 2012. [DOI: 10.1161/hyp.60.suppl_1.a23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Leptin-mediated control of metabolic function requires activation of the proopiomelanocortin (POMC) neurons in the hypothalamus. Whether POMC neurons also control the cardiovascular effects of leptin still remain to be determined. In order to test the hypothesis that POMC neurons regulate leptin-mediated cardiovascular control, protein tyrosine phosphatase 1B (PTP1B), the molecular restrain of the leptin signaling pathway was deleted in the whole animal (PTP1BKO/WT) or specifically in POMC neurons (PTP1BPOMC/flox) of mice on the C57Bl/6 background using the Cre-Lox technique. PTP1B deletion in POMC neurons recapitulates the protective effects of the total KO on the control of body weight and insulin sensitivity. Conscious blood pressure (BP) measurements (telemetry) revealed that neither baseline (PTP1BWT: 103±4 vs. PTP1BKO: 104±7, PTP1Bflox: 112±3 vs. PTP1BPOMC: 117±6 mmHg) nor BP response to chronic leptin infusion (PTP1BWT: 105±6 vs. PTP1BKO: 107±5, PTP1Bflox: 119±3 vs. PTP1BPOMC: 118±3 mmHg) or cage switch stress were affected by the deletion of PTP1B in PTP1BKO and PTP1BPOMC. Sympathetic tone, assessed by measuring the drop in BP in response to ganglionic blockade was increased in PTP1BKO but not in PTP1BPOMC. Vascular adrenergic tone, an index of chronic sympatho-activation inversely correlated to the level of sympathetic activity was measured in isolated aortic rings via wire myography. Aortic rings from PTP1BKO mice exhibited a reduced adrenergic tone (PTP1BWT: 95±7 vs. PTP1BKO: 46±6% of KCl, p<0.05), whereas PTP1BPOMC presented an increased vascular constriction (PTP1Bflox: 85±79 vs. PTP1BPOMC: 112±13% of KCl, p<0.05) non-specific to the adrenergic response. However, the reduction in vascular adrenergic tone induced by chronic leptin infusion was preserved in PTP1BPOMC mice. These data suggest that POMC neurons do not regulate basal sympathetic tone towards the vasculature. These data also highlight the key role of POMC neurons in the control of metabolic function but minimalize their role in the regulation of cardiovascular effects of leptin.
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Abstract
Protein tyrosine phosphatase 1B (PTP1B) is a ubiquitously expressed tyrosine phosphatase implicated in the negative regulation of leptin and insulin receptor signaling. PTP1B(-/-) mice possess a lean metabolic phenotype attributed at least partially to improved hypothalamic leptin sensitivity. Interestingly, mice lacking both leptin and PTP1B (ob/ob:PTP1B(-/-)) have reduced body weight compared with mice lacking leptin only, suggesting that PTP1B may have important leptin-independent metabolic effects. We generated mice with PTP1B deficiency specifically in leptin receptor (LepRb)-expressing neurons (LepRb-PTP1B(-/-)) and compared them with LepRb-Cre-only wild-type (WT) controls and global PTP1B(-/-) mice. Consistent with PTP1B's role as a negative regulator of leptin signaling, our results show that LepRb-PTP1B(-/-) mice are leptin hypersensitive and have significantly reduced body weight when maintained on chow or high-fat diet (HFD) compared with WT controls. LepRb-PTP1B(-/-) mice have a significant decrease in adiposity on HFD compared with controls. Notably, the extent of attenuated body weight gain on HFD, as well as the extent of leptin hypersensitivity, is similar between LepRb-PTP1B(-/-) mice and global PTP1B(-/-) mice. Overall, these results demonstrate that PTP1B deficiency in LepRb-expressing neurons results in reduced body weight and adiposity compared with WT controls and likely underlies the improved metabolic phenotype of global and brain-specific PTP1B-deficient models. Subtle phenotypic differences between LepRb-PTP1B(-/-) and global PTP1B(-/-) mice, however, suggest that PTP1B independent of leptin signaling may also contribute to energy balance in mice.
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Affiliation(s)
- Ryan C Tsou
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6046, USA
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25
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De Jonghe BC, Hayes MR, Zimmer DJ, Kanoski SE, Grill HJ, Bence KK. Food intake reductions and increases in energetic responses by hindbrain leptin and melanotan II are enhanced in mice with POMC-specific PTP1B deficiency. Am J Physiol Endocrinol Metab 2012; 303:E644-51. [PMID: 22761160 PMCID: PMC3468506 DOI: 10.1152/ajpendo.00009.2012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Leptin regulates energy balance through central circuits that control food intake and energy expenditure, including proopiomelanocortin (POMC) neurons. POMC neuron-specific deletion of protein tyrosine phosphatase 1B (PTP1B) (Ptpn1(loxP/loxP) POMC-Cre), a negative regulator of CNS leptin signaling, results in resistance to diet-induced obesity and improved peripheral leptin sensitivity in mice, thus establishing PTP1B as an important component of POMC neuron regulation of energy balance. POMC neurons are expressed in the pituitary, the arcuate nucleus of the hypothalamus (ARH), and the nucleus of the solitary tract (NTS) in the hindbrain, and it is unknown how each population might contribute to the phenotype of POMC-Ptp1b(-/-) mice. It is also unknown whether improved leptin sensitivity in POMC-Ptp1b(-/-) mice involves altered melanocortin receptor signaling. Therefore, we examined the effects of hindbrain administration (4th ventricle) of leptin (1.5, 3, and 6 μg) or the melanocortin 3/4R agonist melanotan II (0.1 and 0.2 nmol) in POMC-Ptp1b(-/-) (KO) and control PTP1B(fl/fl) (WT) mice on food intake, body weight, spontaneous physical activity (SPA), and core temperature (T(C)). The results show that KO mice were hypersensitive to hindbrain leptin- and MTII-induced food intake and body weight suppression and SPA compared with WT mice. Greater increases in leptin- but not MTII-induced T(C) were also observed in KO vs. WT animals. In addition, KO mice displayed elevated hindbrain and hypothalamic MC4R mRNA expression. These studies are the first to show that hindbrain administration of leptin or a melanocortin receptor agonist alters energy balance in mice likely via participation of hindbrain POMC neurons.
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MESH Headings
- Animals
- Appetite Depressants/administration & dosage
- Appetite Depressants/pharmacology
- Appetite Regulation/drug effects
- Dose-Response Relationship, Drug
- Energy Metabolism/drug effects
- Female
- Gene Expression Regulation/drug effects
- Injections, Intraventricular
- Leptin/administration & dosage
- Leptin/metabolism
- Male
- Mice
- Mice, Knockout
- Nerve Tissue Proteins/agonists
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Neurons/drug effects
- Neurons/metabolism
- Organ Specificity
- Peptides, Cyclic/administration & dosage
- Peptides, Cyclic/pharmacology
- Pro-Opiomelanocortin/metabolism
- Protein Tyrosine Phosphatase, Non-Receptor Type 1/deficiency
- Protein Tyrosine Phosphatase, Non-Receptor Type 1/genetics
- Protein Tyrosine Phosphatase, Non-Receptor Type 1/metabolism
- RNA, Messenger/metabolism
- Receptor, Melanocortin, Type 3/agonists
- Receptor, Melanocortin, Type 4/agonists
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Rhombencephalon/drug effects
- Rhombencephalon/metabolism
- alpha-MSH/administration & dosage
- alpha-MSH/analogs & derivatives
- alpha-MSH/pharmacology
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Affiliation(s)
- Bart C De Jonghe
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia PA, USA
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26
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Kanoski SE, Zhao S, Guarnieri DJ, DiLeone RJ, Yan J, De Jonghe BC, Bence KK, Hayes MR, Grill HJ. Endogenous leptin receptor signaling in the medial nucleus tractus solitarius affects meal size and potentiates intestinal satiation signals. Am J Physiol Endocrinol Metab 2012; 303:E496-503. [PMID: 22693203 PMCID: PMC3423098 DOI: 10.1152/ajpendo.00205.2012] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Leptin receptor (LepRb) signaling in the hindbrain is required for energy balance control. Yet the specific hindbrain neurons and the behavioral processes mediating energy balance control by hindbrain leptin signaling are unknown. Studies here employ genetic [adeno-associated virally mediated RNA interference (AAV-RNAi)] and pharmacological methodologies to specify the neurons and the mechanisms through which hindbrain LepRb signaling contributes to the control of food intake. Results show that AAV-RNAi-mediated LepRb knockdown targeting a region encompassing the mNTS and area postrema (AP) (mNTS/AP LepRbKD) increases overall cumulative food intake by increasing the size of spontaneous meals. Other results show that pharmacological hindbrain leptin delivery and RNAi-mediated mNTS/AP LepRb knockdown increased and decreased the intake-suppressive effects of intraduodenal nutrient infusion, respectively. These meal size and intestinally derived signal amplification effects are likely mediated by LepRb signaling in the mNTS and not the AP, since 4th icv and mNTS parenchymal leptin (0.5 μg) administration reduced food intake, whereas this dose did not influence food intake when injected into the AP. Overall, these findings deepen the understanding of the distributed neuronal systems and behavioral mechanisms that mediate the effects of leptin receptor signaling on the control of food intake.
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Affiliation(s)
- Scott E Kanoski
- Dept. of Psychology, School of Arts and Sciences, Univ. of Pennsylvania, 3720 Walnut St., Philadelphia, PA 19104, USA
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27
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Fuentes F, Zimmer D, Atienza M, Schottenfeld J, Penkala I, Bale T, Bence KK, Arregui CO. Protein tyrosine phosphatase PTP1B is involved in hippocampal synapse formation and learning. PLoS One 2012; 7:e41536. [PMID: 22844492 PMCID: PMC3402386 DOI: 10.1371/journal.pone.0041536] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 06/22/2012] [Indexed: 01/01/2023] Open
Abstract
ER-bound PTP1B is expressed in hippocampal neurons, and accumulates among neurite contacts. PTP1B dephosphorylates ß-catenin in N-cadherin complexes ensuring cell-cell adhesion. Here we show that endogenous PTP1B, as well as expressed GFP-PTP1B, are present in dendritic spines of hippocampal neurons in culture. GFP-PTP1B overexpression does not affect filopodial density or length. In contrast, impairment of PTP1B function or genetic PTP1B-deficiency leads to increased filopodia-like dendritic spines and a reduction in mushroom-like spines, while spine density is unaffected. These morphological alterations are accompanied by a disorganization of pre- and post-synapses, as judged by decreased clustering of synapsin-1 and PSD-95, and suggest a dynamic synaptic phenotype. Notably, levels of ß-catenin-Tyr-654 phosphorylation increased ∼5-fold in the hippocampus of adult PTP1B−/− (KO) mice compared to wild type (WT) mice and this was accompanied by a reduction in the amount of ß-catenin associated with N-cadherin. To determine whether PTP1B-deficiency alters learning and memory, we generated mice lacking PTP1B in the hippocampus and cortex (PTP1Bfl/fl–Emx1-Cre). PTP1Bfl/fl–Emx1-Cre mice displayed improved performance in the Barnes maze (decreased time to find and enter target hole), utilized a more efficient strategy (cued), and had better recall compared to WT controls. Our results implicate PTP1B in structural plasticity within the hippocampus, likely through modulation of N-cadherin function by ensuring dephosphorylation of ß-catenin on Tyr-654. Disruption of hippocampal PTP1B function or expression leads to elongation of dendritic filopodia and improved learning and memory, demonstrating an exciting novel role for this phosphatase.
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Affiliation(s)
- Federico Fuentes
- Instituto de Investigaciones Biotecnológicas, Universidad de San Martín/CONICET, San Martín, Buenos Aires, Argentina
| | - Derek Zimmer
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Marybless Atienza
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jamie Schottenfeld
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Ian Penkala
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Tracy Bale
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Kendra K. Bence
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (COA); (KKB)
| | - Carlos O. Arregui
- Instituto de Investigaciones Biotecnológicas, Universidad de San Martín/CONICET, San Martín, Buenos Aires, Argentina
- * E-mail: (COA); (KKB)
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28
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Owen C, Czopek A, Agouni A, Grant L, Judson R, Lees EK, Mcilroy GD, Göransson O, Welch A, Bence KK, Kahn BB, Neel BG, Mody N, Delibegović M. Adipocyte-specific protein tyrosine phosphatase 1B deletion increases lipogenesis, adipocyte cell size and is a minor regulator of glucose homeostasis. PLoS One 2012; 7:e32700. [PMID: 22389718 PMCID: PMC3289674 DOI: 10.1371/journal.pone.0032700] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 01/30/2012] [Indexed: 12/16/2022] Open
Abstract
Protein tyrosine phosphatase 1B (PTP1B), a key negative regulator of leptin and insulin signaling, is positively correlated with adiposity and contributes to insulin resistance. Global PTP1B deletion improves diet-induced obesity and glucose homeostasis via enhanced leptin signaling in the brain and increased insulin signaling in liver and muscle. However, the role of PTP1B in adipocytes is unclear, with studies demonstrating beneficial, detrimental or no effect(s) of adipose-PTP1B-deficiency on body mass and insulin resistance. To definitively establish the role of adipocyte-PTP1B in body mass regulation and glucose homeostasis, adipocyte-specific-PTP1B knockout mice (adip-crePTP1B−/−) were generated using the adiponectin-promoter to drive Cre-recombinase expression. Chow-fed adip-crePTP1B−/− mice display enlarged adipocytes, despite having similar body weight/adiposity and glucose homeostasis compared to controls. High-fat diet (HFD)-fed adip-crePTP1B−/− mice display no differences in body weight/adiposity but exhibit larger adipocytes, increased circulating glucose and leptin levels, reduced leptin sensitivity and increased basal lipogenesis compared to controls. This is associated with decreased insulin receptor (IR) and Akt/PKB phosphorylation, increased lipogenic gene expression and increased hypoxia-induced factor-1-alpha (Hif-1α) expression. Adipocyte-specific PTP1B deletion does not beneficially manipulate signaling pathways regulating glucose homeostasis, lipid metabolism or adipokine secretion in adipocytes. Moreover, PTP1B does not appear to be the major negative regulator of the IR in adipocytes.
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Affiliation(s)
- Carl Owen
- Integrative Physiology, University of Aberdeen, Aberdeen, United Kingdom
| | - Alicja Czopek
- Integrative Physiology, University of Aberdeen, Aberdeen, United Kingdom
| | - Abdelali Agouni
- Integrative Physiology, University of Aberdeen, Aberdeen, United Kingdom
| | - Louise Grant
- Integrative Physiology, University of Aberdeen, Aberdeen, United Kingdom
| | - Robert Judson
- School of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Emma K. Lees
- Integrative Physiology, University of Aberdeen, Aberdeen, United Kingdom
| | - George D. Mcilroy
- Integrative Physiology, University of Aberdeen, Aberdeen, United Kingdom
| | - Olga Göransson
- Department of Experimental Medical Science, Protein Phosphorylation Unit, Lund University, Lund, Sweden
| | - Andy Welch
- School of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Kendra K. Bence
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, United States of America
| | - Barbara B. Kahn
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Centre, Boston, United States of America
| | - Benjamin G. Neel
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Hospital, University of Toronto, Toronto, Canada
| | - Nimesh Mody
- Integrative Physiology, University of Aberdeen, Aberdeen, United Kingdom
| | - Mirela Delibegović
- Integrative Physiology, University of Aberdeen, Aberdeen, United Kingdom
- * E-mail:
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29
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Tsou RC, Bence KK. The Genetics of PTPN1 and Obesity: Insights from Mouse Models of Tissue-Specific PTP1B Deficiency. J Obes 2012; 2012:926857. [PMID: 22811891 PMCID: PMC3395189 DOI: 10.1155/2012/926857] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 04/18/2012] [Accepted: 04/18/2012] [Indexed: 02/05/2023] Open
Abstract
The protein tyrosine phosphatase PTP1B is a negative regulator of both insulin and leptin signaling and is involved in the control of glucose homeostasis and energy expenditure. Due to its prominent role in regulating metabolism, PTP1B is a promising therapeutic target for the treatment of human obesity and type 2 diabetes. The PTP1B protein is encoded by the PTPN1 gene on human chromosome 20q13, a region that shows linkage with insulin resistance, type 2 diabetes, and obesity in human populations. In this paper, we summarize the genetics of the PTPN1 locus and associations with metabolic disease. In addition, we discuss the tissue-specific functions of PTP1B as gleaned from genetic mouse models.
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Affiliation(s)
- Ryan C. Tsou
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Vet 223E, Philadelphia, PA 19104, USA
| | - Kendra K. Bence
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Vet 223E, Philadelphia, PA 19104, USA
- *Kendra K. Bence:
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30
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Loh K, Fukushima A, Zhang X, Galic S, Briggs D, Enriori PJ, Simonds S, Wiede F, Reichenbach A, Hauser C, Sims NA, Bence KK, Zhang S, Zhang ZY, Kahn BB, Neel BG, Andrews ZB, Cowley MA, Tiganis T. Elevated hypothalamic TCPTP in obesity contributes to cellular leptin resistance. Cell Metab 2011; 14:684-99. [PMID: 22000926 PMCID: PMC3263335 DOI: 10.1016/j.cmet.2011.09.011] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 08/20/2011] [Accepted: 09/21/2011] [Indexed: 01/03/2023]
Abstract
In obesity, anorectic responses to leptin are diminished, giving rise to the concept of "leptin resistance." Increased expression of protein tyrosine phosphatase 1B (PTP1B) has been associated with the attenuation of leptin signaling and development of cellular leptin resistance. Here we report that hypothalamic levels of the tyrosine phosphatase TCPTP are also elevated in obesity to attenuate the leptin response. We show that mice that lack TCPTP in neuronal cells have enhanced leptin sensitivity and are resistant to high-fat-diet-induced weight gain and the development of leptin resistance. Also, intracerebroventricular administration of a TCPTP inhibitor enhances leptin signaling and responses in mice. Moreover, the combined deletion of TCPTP and PTP1B in neuronal cells has additive effects in the prevention of diet-induced obesity. Our results identify TCPTP as a critical negative regulator of hypothalamic leptin signaling and causally link elevated TCPTP to the development of cellular leptin resistance in obesity.
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Affiliation(s)
- Kim Loh
- Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
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31
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Balavenkatraman KK, Aceto N, Britschgi A, Mueller U, Bence KK, Neel BG, Bentires-Alj M. Epithelial protein-tyrosine phosphatase 1B contributes to the induction of mammary tumors by HER2/Neu but is not essential for tumor maintenance. Mol Cancer Res 2011; 9:1377-84. [PMID: 21849469 DOI: 10.1158/1541-7786.mcr-11-0198] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Protein-tyrosine phosphatase 1B (PTP1B), a well-established metabolic regulator, plays an important role in breast cancer. Using whole-body PTP1B knockout mice, recent studies have shown that PTP1B ablation delays HER2/Neu-induced mammary cancer. Whether PTP1B plays a cell-autonomous or a noncell-autonomous role in HER2/Neu-evoked tumorigenesis and whether it is involved in tumor maintenance was unknown. We generated mice expressing HER2/Neu and lacking PTP1B specifically in the mammary epithelium. We found that mammary-specific deletion of PTP1B delays the onset of HER2/Neu-evoked mammary tumors, establishing a cell autonomous role for PTP1B in such neoplasms. We also deleted PTP1B in established mouse mammary tumors or depleted PTP1B in human breast cancer cell lines grown as xenografts. PTP1B inhibition did not affect tumor growth in either model showing that neither epithelial nor stromal PTP1B is necessary for tumor maintenance. Taken together, our data show that despite the PTP1B contribution to tumor onset, it is not essential for tumor maintenance. This suggests that PTP1B inhibition could be effective in breast tumor prevention.
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32
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De Jonghe BC, Hayes MR, Bence KK. Melanocortin control of energy balance: evidence from rodent models. Cell Mol Life Sci 2011; 68:2569-88. [PMID: 21553232 PMCID: PMC3135719 DOI: 10.1007/s00018-011-0707-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 04/19/2011] [Accepted: 04/20/2011] [Indexed: 01/18/2023]
Abstract
Regulation of energy balance is extremely complex, and involves multiple systems of hormones, neurotransmitters, receptors, and intracellular signals. As data have accumulated over the last two decades, the CNS melanocortin system is now identified as a prominent integrative network of energy balance controls in the mammalian brain. Here, we will review findings from rat and mouse models, which have provided an important framework in which to study melanocortin function. Perhaps most importantly, this review attempts for the first time to summarize recent advances in our understanding of the intracellular signaling pathways thought to mediate the action of melanocortin neurons and peptides in control of longterm energy balance. Special attention will be paid to the roles of MC4R/MC3R, as well as downstream neurotransmitters within forebrain and hindbrain structures that illustrate the distributed control of melanocortin signaling in energy balance. In addition, distinctions and controversy between rodent species will be discussed.
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Affiliation(s)
- Bart C. De Jonghe
- Dept. of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - Matthew R. Hayes
- Dept. of Psychiatry, School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - Kendra K. Bence
- Dept. of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104
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33
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De Jonghe BC, Hayes MR, Banno R, Skibicka KP, Zimmer DJ, Bowen KA, Leichner TM, Alhadeff AL, Kanoski SE, Cyr NE, Nillni EA, Grill HJ, Bence KK. Deficiency of PTP1B in POMC neurons leads to alterations in energy balance and homeostatic response to cold exposure. Am J Physiol Endocrinol Metab 2011; 300:E1002-11. [PMID: 21406615 PMCID: PMC3118594 DOI: 10.1152/ajpendo.00639.2010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The adipose tissue-derived hormone leptin regulates energy balance through catabolic effects on central circuits, including proopiomelanocortin (POMC) neurons. Leptin activation of POMC neurons increases thermogenesis and locomotor activity. Protein tyrosine phosphatase 1B (PTP1B) is an important negative regulator of leptin signaling. POMC neuron-specific deletion of PTP1B in mice results in reduced high-fat diet-induced body weight and adiposity gain due to increased energy expenditure and greater leptin sensitivity. Mice lacking the leptin gene (ob/ob mice) are hypothermic and cold intolerant, whereas leptin delivery to ob/ob mice induces thermogenesis via increased sympathetic activity to brown adipose tissue (BAT). Here, we examined whether POMC PTP1B mediates the thermoregulatory response of CNS leptin signaling by evaluating food intake, body weight, core temperature (T(C)), and spontaneous physical activity (SPA) in response to either exogenous leptin or 4-day cold exposure (4°C) in male POMC-Ptp1b-deficient mice compared with wild-type controls. POMC-Ptp1b(-/-) mice were hypersensitive to leptin-induced food intake and body weight suppression compared with wild types, yet they displayed similar leptin-induced increases in T(C). Interestingly, POMC-Ptp1b(-/-) mice had increased BAT weight and elevated plasma triiodothyronine (T(3)) levels in response to a 4-day cold challenge, as well as reduced SPA 24 h after cold exposure, relative to controls. These data show that PTP1B in POMC neurons plays a role in short-term cold-induced reduction of SPA and may influence cold-induced thermogenesis via enhanced activation of the thyroid axis.
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Affiliation(s)
- Bart C De Jonghe
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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34
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Hayes MR, Leichner TM, Zhao S, Lee GS, Chowansky A, Zimmer D, De Jonghe BC, Kanoski SE, Grill HJ, Bence KK. Intracellular signals mediating the food intake-suppressive effects of hindbrain glucagon-like peptide-1 receptor activation. Cell Metab 2011; 13:320-30. [PMID: 21356521 PMCID: PMC3108145 DOI: 10.1016/j.cmet.2011.02.001] [Citation(s) in RCA: 167] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 11/23/2010] [Accepted: 01/28/2011] [Indexed: 12/12/2022]
Abstract
Glucagon-like peptide-1 receptor (GLP-1R) activation within the nucleus tractus solitarius (NTS) suppresses food intake and body weight (BW), but the intracellular signals mediating these effects are unknown. Here, hindbrain (fourth i.c.v.) GLP-1R activation by Exendin-4 (Ex-4) increased PKA and MAPK activity and decreased phosphorylation of AMPK in NTS. PKA and MAPK signaling contribute to food intake and BW suppression by Ex-4, as inhibitors RpcAMP and U0126 (fourth i.c.v.), respectively, attenuated Ex-4's effects. Hindbrain GLP-1R activation inhibited feeding by reducing meal number, not meal size. This effect was attenuated with stimulation of AMPK activity by AICAR (fourth i.c.v.). The PKA, MAPK, and AMPK signaling responses by Ex-4 were present in immortalized GLP-1R-expressing neurons (GT1-7). In conclusion, hindbrain GLP-1R activation suppresses food intake and BW through coordinated PKA-mediated suppression of AMPK and activation of MAPK. Pharmacotherapies targeting these signaling pathways, which mediate intake-suppressive effects of CNS GLP-1R activation, may prove efficacious in treating obesity.
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Affiliation(s)
- Matthew R. Hayes
- Department of Psychology, School of Arts and Sciences, University of Pennsylvania, 3720 Walnut St, Philadelphia PA 19104
- Department of Psychiatry, School of Medicine, University of Pennsylvania, 3720 Walnut St, Philadelphia PA 19104
| | - Theresa M. Leichner
- Department of Psychology, School of Arts and Sciences, University of Pennsylvania, 3720 Walnut St, Philadelphia PA 19104
| | - Shiru Zhao
- Department of Psychology, School of Arts and Sciences, University of Pennsylvania, 3720 Walnut St, Philadelphia PA 19104
| | - Grace S. Lee
- Department of Psychology, School of Arts and Sciences, University of Pennsylvania, 3720 Walnut St, Philadelphia PA 19104
| | - Amy Chowansky
- Department of Psychology, School of Arts and Sciences, University of Pennsylvania, 3720 Walnut St, Philadelphia PA 19104
| | - Derek Zimmer
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 3720 Walnut St, Philadelphia PA 19104
| | - Bart C. De Jonghe
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 3720 Walnut St, Philadelphia PA 19104
| | - Scott E. Kanoski
- Department of Psychology, School of Arts and Sciences, University of Pennsylvania, 3720 Walnut St, Philadelphia PA 19104
| | - Harvey J. Grill
- Department of Psychology, School of Arts and Sciences, University of Pennsylvania, 3720 Walnut St, Philadelphia PA 19104
| | - Kendra K. Bence
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 3720 Walnut St, Philadelphia PA 19104
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Bence KK. Hepatic PTP1B Deficiency: The Promise of a Treatment for Metabolic Syndrome? J Clin Metab Diabetes 2010; 1:27-33. [PMID: 21533018 PMCID: PMC3083115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Metabolic syndrome and type 2 diabetes are complex disorders that are associated with obesity, aging, and genetic predisposition. The increasing prevalence of metabolic abnormalities worldwide presents a serious public health problem, with rates of obesity and diabetes reaching unprecedented levels. A common feature of these disorders is the development of insulin resistance, resulting in decreased insulin-stimulated glucose uptake, failure to suppress hepatic glucose production, and accumulation of hepatic lipid. Recent studies in mice have shown that deficiency of the non-receptor protein tyrosine phosphatase, PTP1B, in liver leads to a host of improvements in metabolic parameters, including improved hepatic insulin sensitivity, reduced liver triglycerides, lower serum and hepatic cholesterol levels, and protection against high-fat diet-induced endoplasmic reticulum (ER) stress. Based on these promising studies, PTP1B inhibitors may prove to be a valuable therapeutic tool in the fight against metabolic syndrome and its associated comorbidities. In this review, the role of PTP1B in hepatic insulin sensitivity, hepatic lipid accumulation, and ER stress are discussed.
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Affiliation(s)
- Kendra K Bence
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Banno R, Zimmer D, De Jonghe BC, Atienza M, Rak K, Yang W, Bence KK. PTP1B and SHP2 in POMC neurons reciprocally regulate energy balance in mice. J Clin Invest 2010; 120:720-34. [PMID: 20160350 DOI: 10.1172/jci39620] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Accepted: 12/16/2009] [Indexed: 12/13/2022] Open
Abstract
Protein tyrosine phosphatase 1B (PTP1B) and SH2 domain-containing protein tyrosine phosphatase-2 (SHP2) have been shown in mice to regulate metabolism via the central nervous system, but the specific neurons mediating these effects are unknown. Here, we have shown that proopiomelanocortin (POMC) neuron-specific deficiency in PTP1B or SHP2 in mice results in reciprocal effects on weight gain, adiposity, and energy balance induced by high-fat diet. Mice with POMC neuron-specific deletion of the gene encoding PTP1B (referred to herein as POMC-Ptp1b-/- mice) had reduced adiposity, improved leptin sensitivity, and increased energy expenditure compared with wild-type mice, whereas mice with POMC neuron-specific deletion of the gene encoding SHP2 (referred to herein as POMC-Shp2-/- mice) had elevated adiposity, decreased leptin sensitivity, and reduced energy expenditure. POMC-Ptp1b-/- mice showed substantially improved glucose homeostasis on a high-fat diet, and hyperinsulinemic-euglycemic clamp studies revealed that insulin sensitivity in these mice was improved on a standard chow diet in the absence of any weight difference. In contrast, POMC-Shp2-/- mice displayed impaired glucose tolerance only secondary to their increased weight gain. Interestingly, hypothalamic Pomc mRNA and alpha-melanocyte-stimulating hormone (alphaMSH) peptide levels were markedly reduced in POMC-Shp2-/- mice. These studies implicate PTP1B and SHP2 as important components of POMC neuron regulation of energy balance and point to what we believe to be a novel role for SHP2 in the normal function of the melanocortin system.
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Affiliation(s)
- Ryoichi Banno
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104-6046, USA
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Bence KK, Delibegovic M, Xue B, Gorgun CZ, Hotamisligil GS, Neel BG, Kahn BB. Addendum: Neuronal PTP1B regulates body weight, adiposity and leptin action. Nat Med 2010. [DOI: 10.1038/nm0210-237b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Hayes MR, Skibicka KP, Leichner TM, Guarnieri DJ, DiLeone RJ, Bence KK, Grill HJ. Endogenous leptin signaling in the caudal nucleus tractus solitarius and area postrema is required for energy balance regulation. Cell Metab 2010; 11:77-83. [PMID: 20074530 PMCID: PMC2807619 DOI: 10.1016/j.cmet.2009.10.009] [Citation(s) in RCA: 164] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 09/04/2009] [Accepted: 10/27/2009] [Indexed: 01/02/2023]
Abstract
Medial nucleus tractus solitarius (mNTS) neurons express leptin receptors (LepRs), and intra-mNTS delivery of leptin reduces food intake and body weight. Here, the contribution of endogenous LepR signaling in mNTS neurons to energy balance control was examined. Knockdown of LepR in mNTS and area postrema (AP) neurons of rats (LepRKD) via adeno-associated virus short hairpin RNA-interference (AAV-shRNAi) resulted in significant hyperphagia for chow, high-fat, and sucrose diets, yielding increased body weight and adiposity. The chronic hyperphagia of mNTS/AP LepRKD rats is likely mediated by a reduction in leptin potentiation of gastrointestinal satiation signaling, as LepRKD rats showed decreased sensitivity to the intake-reducing effects of cholecystokinin. LepRKD rats showed increased basal AMP-kinase activity in mNTS/AP micropunches, and pharmacological data suggest that this increase provides a likely mechanism for their chronic hyperphagia. Overall these findings demonstrate that LepRs in mNTS and AP neurons are required for normal energy balance control.
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Abstract
The fuel-sensing enzyme AMP-activated protein kinase (AMPK) has been implicated in central nervous system control of energy balance. Hypothalamic AMPK activity is increased by food deprivation, and this elevation is inhibited by refeeding or by leptin treatment. The contribution of extrahypothalamic AMPK activity in energy balance control has not been addressed. Here, we investigate the effects of physiological state on the AMPK activity in hindbrain nucleus tractus solitarius (NTS) neurons because treatments that reduce energy availability in these neurons trigger behavioral, endocrine, and autonomic responses to restore energy balance. Food-deprived rats showed significantly increased AMPK activity in both NTS- and hypothalamus-enriched lysates compared with those that were ad libitum fed. Pharmacological inhibition of AMPK activity in medial NTS neurons, by intraparenchymal injection of compound C, suppressed food intake and body weight gain compared with vehicle. Fourth ventricle (4th i.c.v.) compound C delivery increased heart rate and spontaneous activity in free-moving rats. Suppression of AMPK activity has been implicated in leptin's anorectic action in the hypothalamus. Given the role of leptin signaling in food intake inhibition within the medial NTS, we also examined whether stimulation of hindbrain AMPK by 4th i.c.v. administration of 5-aminoimidazole-4-carboxamide-riboside (AICAR), an AMP-mimicking promoter of AMPK activity, could attenuate the inhibition of food intake by 4th i.c.v. leptin. The intake-suppressive effects of leptin (at 2 and 4 h) were completely reversed by AICAR. We conclude that 1) hindbrain AMPK activity contributes to energy balance control through regulation of food intake and energy expenditure, 2) leptin's intake-reducing effects in the NTS are mediated by AMPK, and 3) central nervous system AMPK controls whole-body homeostasis at anatomically distributed sites across the neuraxis.
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Affiliation(s)
- Matthew R Hayes
- Graduate Group of Psychology, University of Pennsylvania, 3720 Walnut Street, Philadelphia, Pennsylvania 19104, USA.
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Delibegovic M, Zimmer D, Kauffman C, Rak K, Hong EG, Cho YR, Kim JK, Kahn BB, Neel BG, Bence KK. Liver-specific deletion of protein-tyrosine phosphatase 1B (PTP1B) improves metabolic syndrome and attenuates diet-induced endoplasmic reticulum stress. Diabetes 2009; 58:590-9. [PMID: 19074988 PMCID: PMC2646057 DOI: 10.2337/db08-0913] [Citation(s) in RCA: 210] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE The protein tyrosine phosphatase PTP1B is a negative regulator of insulin signaling; consequently, mice deficient in PTP1B are hypersensitive to insulin. Because PTP1B(-/-) mice have diminished fat stores, the extent to which PTP1B directly regulates glucose homeostasis is unclear. Previously, we showed that brain-specific PTP1B(-/-) mice are protected against high-fat diet-induced obesity and glucose intolerance, whereas muscle-specific PTP1B(-/-) mice have increased insulin sensitivity independent of changes in adiposity. Here we studied the role of liver PTP1B in glucose homeostasis and lipid metabolism. RESEARCH DESIGN AND METHODS We analyzed body mass/adiposity, insulin sensitivity, glucose tolerance, and lipid metabolism in liver-specific PTP1B(-/-) and PTP1Bfl/fl control mice, fed a chow or high-fat diet. RESULTS Compared with normal littermates, liver-specific PTP1B(-/-) mice exhibit improved glucose homeostasis and lipid profiles, independent of changes in adiposity. Liver-specific PTP1B(-/-) mice have increased hepatic insulin signaling, decreased expression of gluconeogenic genes PEPCK and G-6-Pase, enhanced insulin-induced suppression of hepatic glucose production, and improved glucose tolerance. Liver-specific PTP1B(-/-) mice exhibit decreased triglyceride and cholesterol levels and diminished expression of lipogenic genes SREBPs, FAS, and ACC. Liver-specific PTP1B deletion also protects against high-fat diet-induced endoplasmic reticulum stress response in vivo, as evidenced by decreased phosphorylation of p38MAPK, JNK, PERK, and eIF2alpha and lower expression of the transcription factors C/EBP homologous protein and spliced X box-binding protein 1. CONCLUSIONS Liver PTP1B plays an important role in glucose and lipid metabolism, independent of alterations in adiposity. Inhibition of PTP1B in peripheral tissues may be useful for the treatment of metabolic syndrome and reduction of cardiovascular risk in addition to diabetes.
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Affiliation(s)
- Mirela Delibegovic
- Cancer Biology Program, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
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Kontaridis MI, Yang W, Bence KK, Cullen D, Wang B, Bodyak N, Ke Q, Hinek A, Kang PM, Liao R, Neel BG. Deletion of Ptpn11 (Shp2) in cardiomyocytes causes dilated cardiomyopathy via effects on the extracellular signal-regulated kinase/mitogen-activated protein kinase and RhoA signaling pathways. Circulation 2008; 117:1423-35. [PMID: 18316486 DOI: 10.1161/circulationaha.107.728865] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Heart failure is the leading cause of death in the United States. By delineating the pathways that regulate cardiomyocyte function, we can better understand the pathogenesis of cardiac disease. Many cardiomyocyte signaling pathways activate protein tyrosine kinases. However, the role of specific protein tyrosine phosphatases (PTPs) in these pathways is unknown. METHODS AND RESULTS Here, we show that mice with muscle-specific deletion of Ptpn11, the gene encoding the SH2 domain-containing PTP Shp2, rapidly develop a compensated dilated cardiomyopathy without an intervening hypertrophic phase, with signs of cardiac dysfunction appearing by the second postnatal month. Shp2-deficient primary cardiomyocytes are defective in extracellular signal-regulated kinase/mitogen-activated protein kinase (Erk/MAPK) activation in response to a variety of soluble agonists and pressure overload but show hyperactivation of the RhoA signaling pathway. Treatment of primary cardiomyocytes with Erk1/2- and RhoA pathway-specific inhibitors suggests that both abnormal Erk/MAPK and RhoA activities contribute to the dilated phenotype of Shp2-deficient hearts. CONCLUSIONS Our results identify Shp2 as the first PTP with a critical role in adult cardiac function, indicate that in the absence of Shp2 cardiac hypertrophy does not occur in response to pressure overload, and demonstrate that the cardioprotective role of Shp2 is mediated via control of both the Erk/MAPK and RhoA signaling pathways.
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Affiliation(s)
- Maria I Kontaridis
- Cancer Biology Program, Department of Medicine, Beth Israel Deaconess Medical Center, NRB, Room 1036, 77 Ave Louis Pasteur, Boston, MA 02115, USA.
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Delibegovic M, Bence KK, Mody N, Hong EG, Ko HJ, Kim JK, Kahn BB, Neel BG. Improved glucose homeostasis in mice with muscle-specific deletion of protein-tyrosine phosphatase 1B. Mol Cell Biol 2007; 27:7727-34. [PMID: 17724080 PMCID: PMC2169063 DOI: 10.1128/mcb.00959-07] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Obesity and type 2 diabetes are characterized by insulin resistance. Mice lacking the protein-tyrosine phosphatase PTP1B in all tissues are hypersensitive to insulin but also have diminished fat stores. Because adiposity affects insulin sensitivity, the extent to which PTP1B directly regulates glucose homeostasis has been unclear. We report that mice lacking PTP1B only in muscle have body weight and adiposity comparable to those of controls on either chow or a high-fat diet (HFD). Muscle triglycerides and serum adipokines are also affected similarly by HFD in both groups. Nevertheless, muscle-specific PTP1B(-/-) mice exhibit increased muscle glucose uptake, improved systemic insulin sensitivity, and enhanced glucose tolerance. These findings correlate with and are most likely caused by increased phosphorylation of the insulin receptor and its downstream signaling components. Thus, muscle PTP1B plays a major role in regulating insulin action and glucose homeostasis, independent of adiposity. In addition, rosiglitazone treatment of HFD-fed control and muscle-specific PTP1B(-/-) mice revealed that rosiglitazone acts additively with PTP1B deletion. Therefore, combining PTP1B inhibition with thiazolidinediones should be more effective than either alone for treating insulin-resistant states.
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Affiliation(s)
- Mirela Delibegovic
- Cancer Biology Program, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
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Bence KK, Delibegovic M, Xue B, Gorgun CZ, Hotamisligil GS, Neel BG, Kahn BB. Neuronal PTP1B regulates body weight, adiposity and leptin action. Nat Med 2006; 12:917-24. [PMID: 16845389 DOI: 10.1038/nm1435] [Citation(s) in RCA: 474] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Accepted: 05/16/2006] [Indexed: 11/08/2022]
Abstract
Obesity is a major health problem and a risk factor for type 2 diabetes. Leptin, an adipocyte-secreted hormone, acts on the hypothalamus to inhibit food intake and increase energy expenditure. Most obese individuals develop hyperleptinemia and leptin resistance, limiting the therapeutic efficacy of exogenously administered leptin. Mice lacking the tyrosine phosphatase PTP1B are protected from diet-induced obesity and are hypersensitive to leptin, but the site and mechanism for these effects remain controversial. We generated tissue-specific PTP1B knockout (Ptpn1(-/-)) mice. Neuronal Ptpn1(-/-) mice have reduced weight and adiposity, and increased activity and energy expenditure. In contrast, adipose PTP1B deficiency increases body weight, whereas PTP1B deletion in muscle or liver does not affect weight. Neuronal Ptpn1(-/-) mice are hypersensitive to leptin, despite paradoxically elevated leptin levels, and show improved glucose homeostasis. Thus, PTP1B regulates body mass and adiposity primarily through actions in the brain. Furthermore, neuronal PTP1B regulates adipocyte leptin production and probably is essential for the development of leptin resistance.
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Affiliation(s)
- Kendra K Bence
- Cancer Biology Program, Division of Hematology/Oncology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, NRB 1030, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA
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Affiliation(s)
- L A Blair
- Brown University, Providence, Rhode Island 02912, USA
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