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Gogiraju R, Witzler C, Shahneh F, Hubert A, Renner L, Bochenek ML, Zifkos K, Becker C, Thati M, Schäfer K. Deletion of endothelial leptin receptors in mice promotes diet-induced obesity. Sci Rep 2023; 13:8276. [PMID: 37217565 DOI: 10.1038/s41598-023-35281-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 05/16/2023] [Indexed: 05/24/2023] Open
Abstract
Obesity promotes endothelial dysfunction. Endothelial cells not only respond, but possibly actively promote the development of obesity and metabolic dysfunction. Our aim was to characterize the role of endothelial leptin receptors (LepR) for endothelial and whole body metabolism and diet-induced obesity. Mice with tamoxifen-inducible, Tie2.Cre-ERT2-mediated deletion of LepR in endothelial cells (End.LepR knockout, KO) were fed high-fat diet (HFD) for 16 weeks. Body weight gain, serum leptin levels, visceral adiposity and adipose tissue inflammation were more pronounced in obese End.LepR-KO mice, whereas fasting serum glucose and insulin levels or the extent of hepatic steatosis did not differ. Reduced brain endothelial transcytosis of exogenous leptin, increased food intake and total energy balance were observed in End.LepR-KO mice and accompanied by brain perivascular macrophage accumulation, whereas physical activity, energy expenditure and respiratory exchange rates did not differ. Metabolic flux analysis revealed no changes in the bioenergetic profile of endothelial cells from brain or visceral adipose tissue, but higher glycolysis and mitochondrial respiration rates in those isolated from lungs. Our findings support a role for endothelial LepRs in the transport of leptin into the brain and neuronal control of food intake, and also suggest organ-specific changes in endothelial cell, but not whole-body metabolism.
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Affiliation(s)
- Rajinikanth Gogiraju
- Department of Cardiology, Cardiology I, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Claudius Witzler
- Center for Thrombosis and Hemostasis, University Medical Center Mainz, Mainz, Germany
| | - Fatemeh Shahneh
- Center for Thrombosis and Hemostasis, University Medical Center Mainz, Mainz, Germany
| | - Astrid Hubert
- Department of Cardiology, Cardiology I, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Luisa Renner
- Department of Cardiology, Cardiology I, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Magdalena L Bochenek
- Department of Cardiology, Cardiology I, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
- Center for Thrombosis and Hemostasis, University Medical Center Mainz, Mainz, Germany
| | - Konstantinos Zifkos
- Center for Thrombosis and Hemostasis, University Medical Center Mainz, Mainz, Germany
| | - Christian Becker
- Center for Thrombosis and Hemostasis, University Medical Center Mainz, Mainz, Germany
- Clinic of Dermatology, University Clinic Münster, Münster, Germany
| | - Madhusudhan Thati
- Center for Thrombosis and Hemostasis, University Medical Center Mainz, Mainz, Germany
| | - Katrin Schäfer
- Department of Cardiology, Cardiology I, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.
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2
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Tsirigotaki A, Dansercoer A, Verschueren KHG, Marković I, Pollmann C, Hafer M, Felix J, Birck C, Van Putte W, Catteeuw D, Tavernier J, Fernando Bazan J, Piehler J, Savvides SN, Verstraete K. Mechanism of receptor assembly via the pleiotropic adipokine Leptin. Nat Struct Mol Biol 2023; 30:551-563. [PMID: 36959263 DOI: 10.1038/s41594-023-00941-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/06/2023] [Indexed: 03/25/2023]
Abstract
The adipokine Leptin activates its receptor LEP-R in the hypothalamus to regulate body weight and exerts additional pleiotropic functions in immunity, fertility and cancer. However, the structure and mechanism of Leptin-mediated LEP-R assemblies has remained unclear. Intriguingly, the signaling-competent isoform of LEP-R is only lowly abundant amid several inactive short LEP-R isoforms contributing to a mechanistic conundrum. Here we show by X-ray crystallography and cryo-EM that, in contrast to long-standing paradigms, Leptin induces type I cytokine receptor assemblies featuring 3:3 stoichiometry and demonstrate such Leptin-induced trimerization of LEP-R on living cells via single-molecule microscopy. In mediating these assemblies, Leptin undergoes drastic restructuring that activates its site III for binding to the Ig domain of an adjacent LEP-R. These interactions are abolished by mutations linked to obesity. Collectively, our study provides the structural and mechanistic framework for how evolutionarily conserved Leptin:LEP-R assemblies with 3:3 stoichiometry can engage distinct LEP-R isoforms to achieve signaling.
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Affiliation(s)
- Alexandra Tsirigotaki
- Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
- Unit for Structural Biology, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Ann Dansercoer
- Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
- Unit for Structural Biology, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Koen H G Verschueren
- Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
- Unit for Structural Biology, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Iva Marković
- Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
- Unit for Structural Biology, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Christoph Pollmann
- Department of Biology/Chemistry and Center for Cellular Nanoanalytics, Osnabrück University, Osnabrück, Germany
| | - Maximillian Hafer
- Department of Biology/Chemistry and Center for Cellular Nanoanalytics, Osnabrück University, Osnabrück, Germany
| | - Jan Felix
- Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
- Unit for Structural Biology, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Catherine Birck
- Integrated Structural Biology Platform, Centre for Integrative Biology (CBI), Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS UMR 7104, INSERM U1258, University of Strasbourg, Illkirch, France
| | | | - Dominiek Catteeuw
- VIB-UGent Center for Medical Biotechnology, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Jan Tavernier
- VIB-UGent Center for Medical Biotechnology, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- Orionis Biosciences, Ghent, Belgium
| | - J Fernando Bazan
- Unit for Structural Biology, VIB-UGent Center for Inflammation Research, Ghent, Belgium
- ħ Bioconsulting llc, Stillwater, MN, USA
| | - Jacob Piehler
- Department of Biology/Chemistry and Center for Cellular Nanoanalytics, Osnabrück University, Osnabrück, Germany
| | - Savvas N Savvides
- Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium.
- Unit for Structural Biology, VIB-UGent Center for Inflammation Research, Ghent, Belgium.
| | - Kenneth Verstraete
- Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium.
- Unit for Structural Biology, VIB-UGent Center for Inflammation Research, Ghent, Belgium.
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3
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Atis M, Akcan U, Altunsu D, Ayvaz E, Uğur Yılmaz C, Sarıkaya D, Temizyürek A, Ahıshalı B, Girouard H, Kaya M. Targeting the blood-brain barrier disruption in hypertension by ALK5/TGF-Β type I receptor inhibitor SB-431542 and dynamin inhibitor dynasore. Brain Res 2022; 1794:148071. [PMID: 36058283 DOI: 10.1016/j.brainres.2022.148071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/17/2022] [Accepted: 08/29/2022] [Indexed: 11/02/2022]
Abstract
INTRODUCTION In this study, we aimed to target two molecules, transforming growth factor-beta (TGF-β) and dynamin to explore their roles in blood-brain barrier (BBB) disruption in hypertension. METHODS For this purpose, angiotensin (ANG) II-induced hypertensive mice were treated with SB-431542, an inhibitor of the ALK5/TGF-β type I receptor, and dynasore, an inhibitor of dynamin. Albumin-Alexa fluor 594 was used to assess BBB permeability. The alterations in the expression of claudin-5, caveolin (Cav)-1, glucose transporter (Glut)-1, and SMAD4 in the cerebral cortex and the hippocampus were evaluated by quantification of immunofluorescence staining intensity. RESULTS ANG II infusion increased BBB permeability to albumin-Alexa fluor 594 which was reduced by SB-431542 (P < 0.01), but not by dynasore. In hypertensive animals treated with dynasore, claudin-5 immunofluorescence intensity increased in the cerebral cortex and hippocampus while it decreased in the cerebral cortex of SB-431542 treated hypertensive mice (P < 0.01). Both dynasore and SB-431542 prevented the increased Cav-1 immunofluorescence intensity in the cerebral cortex and hippocampus of hypertensive animals (P < 0.01). SB-431542 and dynasore decreased Glut-1 immunofluorescence intensity in the cerebral cortex and hippocampus of mice receiving ANG II (P < 0.01). SB-431542 increased SMAD4 immunofluorescence intensity in the cerebral cortex of hypertensive animals, while in the hippocampus a significant decrease was noted by both SB-431542 and dynasore (P < 0.01). CONCLUSION Our data suggest that inhibition of the TGFβ type I receptor prevents BBB disruption under hypertensive conditions. These results emphasize the therapeutic potential of targeting TGFβ signaling as a novel treatment modality to protect the brain of hypertensive patients.
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Affiliation(s)
- Muge Atis
- Graduate School of Health Sciences, Koç University, 34450 Istanbul, Turkey
| | - Uğur Akcan
- Graduate School of Health Sciences, Koç University, 34450 Istanbul, Turkey
| | - Deniz Altunsu
- Graduate School of Health Sciences, Koç University, 34450 Istanbul, Turkey
| | - Ecem Ayvaz
- Graduate School of Health Sciences, Koç University, 34450 Istanbul, Turkey
| | - Canan Uğur Yılmaz
- Department of Pharmaceutical Bioscience, Biomedical Centrum, Uppsala University, Sweden
| | - Deniz Sarıkaya
- Department of Physiology, Koç University School of Medicine, 34450 Istanbul, Turkey
| | - Arzu Temizyürek
- Koç University Research Center for Translational Medicine, 34450 Istanbul, Turkey
| | - Bülent Ahıshalı
- Department of Histology and Embryology, Koç University School of Medicine, 34450, Istanbul, Turkey
| | - Hélène Girouard
- Department of Pharmacology and Physiology, Faculty of Medicine, Montreal University, Montreal, QC, Canada
| | - Mehmet Kaya
- Department of Physiology, Koç University School of Medicine, 34450 Istanbul, Turkey; Koç University Research Center for Translational Medicine, 34450 Istanbul, Turkey.
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Sandin ES, Folberth J, Müller-Fielitz H, Pietrzik CU, Herold E, Willnow TE, Pfluger PT, Nogueiras R, Prevot V, Krey T, Schwaninger M. Is LRP2 Involved in Leptin Transport over the Blood-Brain Barrier and Development of Obesity? Int J Mol Sci 2021; 22:ijms22094998. [PMID: 34066779 PMCID: PMC8125945 DOI: 10.3390/ijms22094998] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/28/2021] [Accepted: 04/30/2021] [Indexed: 12/13/2022] Open
Abstract
The mechanisms underlying the transport of leptin into the brain are still largely unclear. While the leptin receptor has been implicated in the transport process, recent evidence has suggested an additional role of LRP2 (megalin). To evaluate the function of LRP2 for leptin transport across the blood-brain barrier (BBB), we developed a novel leptin-luciferase fusion protein (pLG), which stimulated leptin signaling and was transported in an in vitro BBB model based on porcine endothelial cells. The LRP inhibitor RAP did not affect leptin transport, arguing against a role of LRP2. In line with this, the selective deletion of LRP2 in brain endothelial cells and epithelial cells of the choroid plexus did not influence bodyweight, body composition, food intake, or energy expenditure of mice. These findings suggest that LRP2 at the BBB is not involved in the transport of leptin into the brain, nor in the development of obesity as has previously been described.
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Affiliation(s)
- Elvira S. Sandin
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism, University of Lübeck, 23562 Lübeck, Germany; (E.S.S.); (J.F.); (H.M.-F.)
| | - Julica Folberth
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism, University of Lübeck, 23562 Lübeck, Germany; (E.S.S.); (J.F.); (H.M.-F.)
| | - Helge Müller-Fielitz
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism, University of Lübeck, 23562 Lübeck, Germany; (E.S.S.); (J.F.); (H.M.-F.)
| | - Claus U. Pietrzik
- Institute for Pathobiochemistry, University Medical Center of Johannes Gutenberg University Mainz, 55099 Mainz, Germany;
| | - Elisabeth Herold
- Institute of Biochemistry, Center of Structural and Cell Biology in Medicine, University of Lübeck, 23562 Lübeck, Germany; (E.H.); (T.K.)
| | - Thomas E. Willnow
- Molecular Cardiovascular Research, Max-Delbrueck-Center for Molecular Medicine, 13092 Berlin, Germany;
| | - Paul T. Pfluger
- Research Unit Neurobiology of Diabetes, Helmholtz Zentrum München and Technical University Munich, 85764 Neuherberg, Germany;
| | - Ruben Nogueiras
- CIMUS, Universidade de Santiago de Compostela-Instituto de Investigación Sanitaria, 15782 Santiago de Compostela, Spain;
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15782 Santiago de Compostela, Spain
| | - Vincent Prevot
- Lille Neuroscience & Cognition, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Inserm, CHU Lille, University Lille, UMR-S1172, EGID, DISTALZ, F-59000 Lille, France;
| | - Thomas Krey
- Institute of Biochemistry, Center of Structural and Cell Biology in Medicine, University of Lübeck, 23562 Lübeck, Germany; (E.H.); (T.K.)
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, 22607 Hamburg, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, 30625 Hannover, Germany
- Centre for Structural Systems Biology (CSSB), 22607 Hamburg, Germany
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany
| | - Markus Schwaninger
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism, University of Lübeck, 23562 Lübeck, Germany; (E.S.S.); (J.F.); (H.M.-F.)
- Correspondence: ; Tel.: +49-451-3101-7200
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5
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Pereira S, Cline DL, Glavas MM, Covey SD, Kieffer TJ. Tissue-Specific Effects of Leptin on Glucose and Lipid Metabolism. Endocr Rev 2021; 42:1-28. [PMID: 33150398 PMCID: PMC7846142 DOI: 10.1210/endrev/bnaa027] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Indexed: 12/18/2022]
Abstract
The discovery of leptin was intrinsically associated with its ability to regulate body weight. However, the effects of leptin are more far-reaching and include profound glucose-lowering and anti-lipogenic effects, independent of leptin's regulation of body weight. Regulation of glucose metabolism by leptin is mediated both centrally and via peripheral tissues and is influenced by the activation status of insulin signaling pathways. Ectopic fat accumulation is diminished by both central and peripheral leptin, an effect that is beneficial in obesity-associated disorders. The magnitude of leptin action depends upon the tissue, sex, and context being examined. Peripheral tissues that are of particular relevance include the endocrine pancreas, liver, skeletal muscle, adipose tissues, immune cells, and the cardiovascular system. As a result of its potent metabolic activity, leptin is used to control hyperglycemia in patients with lipodystrophy and is being explored as an adjunct to insulin in patients with type 1 diabetes. To fully understand the role of leptin in physiology and to maximize its therapeutic potential, the mechanisms of leptin action in these tissues needs to be further explored.
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Affiliation(s)
- Sandra Pereira
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Daemon L Cline
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Maria M Glavas
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Scott D Covey
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Timothy J Kieffer
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada.,Department of Surgery, University of British Columbia, Vancouver, Canada.,School of Biomedical Engineering, University of British Columbia, Vancouver, Canada
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6
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Bae SH, Goh TS, Kim DS, Lee JS. Leptin in adolescent idiopathic scoliosis – A meta-analysis. J Clin Neurosci 2020; 71:124-128. [DOI: 10.1016/j.jocn.2019.08.106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 08/24/2019] [Indexed: 12/23/2022]
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7
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Leptin Signaling in the Control of Metabolism and Appetite: Lessons from Animal Models. J Mol Neurosci 2018; 66:390-402. [DOI: 10.1007/s12031-018-1185-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 09/24/2018] [Indexed: 12/15/2022]
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8
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Masschaele D, Wauman J, Vandemoortele G, De Sutter D, De Ceuninck L, Eyckerman S, Tavernier J. High-Confidence Interactome for RNF41 Built on Multiple Orthogonal Assays. J Proteome Res 2018; 17:1348-1360. [PMID: 29560723 DOI: 10.1021/acs.jproteome.7b00704] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Ring finger protein 41 (RNF41) is an E3 ubiquitin ligase involved in the ubiquitination and degradation of many proteins including ErbB3 receptors, BIRC6, and parkin. Next to this, RNF41 regulates the intracellular trafficking of certain JAK2-associated cytokine receptors by ubiquitinating and suppressing USP8, which, in turn, destabilizes the ESCRT-0 complex. To further elucidate the function of RNF41 we used different orthogonal approaches to reveal the RNF41 protein complex: affinity purification-mass spectrometry, BioID, and Virotrap. We combined these results with known data sets for RNF41 obtained with microarray MAPPIT and Y2H screens. This way, we establish a comprehensive high-resolution interactome network comprising 175 candidate protein partners. To remove potential methodological artifacts from this network, we distilled the data into a high-confidence interactome map by retaining a total of 19 protein hits identified in two or more of the orthogonal methods. AP2S1, a novel RNF41 interaction partner, was selected from this high-confidence interactome for further functional validation. We reveal a role for AP2S1 in leptin and LIF receptor signaling and show that RNF41 stabilizes and relocates AP2S1.
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Affiliation(s)
- Delphine Masschaele
- Department of Biochemistry, Faculty of Medicine and Health Sciences , Ghent University , Albert Baertsoenkaai 3 , B-9000 Ghent , Belgium.,Center for Medical Biotechnology, VIB , Albert Baertsoenkaai 3 , B-9000 Ghent , Belgium
| | - Joris Wauman
- Department of Biochemistry, Faculty of Medicine and Health Sciences , Ghent University , Albert Baertsoenkaai 3 , B-9000 Ghent , Belgium.,Center for Medical Biotechnology, VIB , Albert Baertsoenkaai 3 , B-9000 Ghent , Belgium
| | - Giel Vandemoortele
- Department of Biochemistry, Faculty of Medicine and Health Sciences , Ghent University , Albert Baertsoenkaai 3 , B-9000 Ghent , Belgium.,Center for Medical Biotechnology, VIB , Albert Baertsoenkaai 3 , B-9000 Ghent , Belgium
| | - Delphine De Sutter
- Department of Biochemistry, Faculty of Medicine and Health Sciences , Ghent University , Albert Baertsoenkaai 3 , B-9000 Ghent , Belgium.,Center for Medical Biotechnology, VIB , Albert Baertsoenkaai 3 , B-9000 Ghent , Belgium
| | - Leentje De Ceuninck
- Department of Biochemistry, Faculty of Medicine and Health Sciences , Ghent University , Albert Baertsoenkaai 3 , B-9000 Ghent , Belgium.,Center for Medical Biotechnology, VIB , Albert Baertsoenkaai 3 , B-9000 Ghent , Belgium
| | - Sven Eyckerman
- Department of Biochemistry, Faculty of Medicine and Health Sciences , Ghent University , Albert Baertsoenkaai 3 , B-9000 Ghent , Belgium.,Center for Medical Biotechnology, VIB , Albert Baertsoenkaai 3 , B-9000 Ghent , Belgium
| | - Jan Tavernier
- Department of Biochemistry, Faculty of Medicine and Health Sciences , Ghent University , Albert Baertsoenkaai 3 , B-9000 Ghent , Belgium.,Center for Medical Biotechnology, VIB , Albert Baertsoenkaai 3 , B-9000 Ghent , Belgium
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Bharadwaj VN, Nguyen DT, Kodibagkar VD, Stabenfeldt SE. Nanoparticle-Based Therapeutics for Brain Injury. Adv Healthc Mater 2018; 7:10.1002/adhm.201700668. [PMID: 29034608 PMCID: PMC5903677 DOI: 10.1002/adhm.201700668] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/06/2017] [Indexed: 12/18/2022]
Abstract
Brain injuries affect a large patient population with major physical and emotional suffering for patients and their relatives; at a significant cost to the society. Effective diagnostic and therapeutic options available for brain injuries are limited by the complex brain injury pathology involving blood-brain barrier (BBB). Brain injuries, including ischemic stroke and brain trauma, initiate BBB opening for a short period of time, which is followed by a second reopening for an extended time. The leaky BBB and/or the alterations in the receptor expression on BBB may provide opportunities for therapeutic delivery via nanoparticles (NPs). The approaches for therapeutic interventions via NP delivery are aimed at salvaging the pericontusional/penumbra area for possible neuroprotection and neurovascular unit preservation. The focus of this progress report is to provide a survey of NP strategies employed in cerebral ischemia and brain trauma and finally provide insights for improved NP-based diagnostic/treatment approaches.
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Affiliation(s)
- Vimala N. Bharadwaj
- School of Biological and Health Systems Engineering, Arizona State University, PO Box 879709, Tempe, AZ 85287, United States
| | - Duong T. Nguyen
- School of Biological and Health Systems Engineering, Arizona State University, PO Box 879709, Tempe, AZ 85287, United States
| | - Vikram D. Kodibagkar
- School of Biological and Health Systems Engineering, Arizona State University, PO Box 879709, Tempe, AZ 85287, United States
| | - Sarah E. Stabenfeldt
- School of Biological and Health Systems Engineering, Arizona State University, PO Box 879709, Tempe, AZ 85287, United States
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10
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Nanoparticles for Targeting Intratumoral Hypoxia: Exploiting a Potential Weakness of Glioblastoma. Pharm Res 2016; 33:2059-77. [DOI: 10.1007/s11095-016-1947-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 05/12/2016] [Indexed: 02/07/2023]
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11
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Collin A, Noacco A, Talvas J, Caldefie-Chézet F, Vasson MP, Farges MC. Enhancement of Lytic Activity by Leptin Is Independent From Lipid Rafts in Murine Primary Splenocytes. J Cell Physiol 2016; 232:101-9. [PMID: 27028718 DOI: 10.1002/jcp.25394] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 03/25/2016] [Indexed: 12/13/2022]
Abstract
Leptin, a pleiotropic adipokine, is known as a regulator of food intake, but it is also involved in inflammation, immunity, cell proliferation, and survival. Leptin receptor is integrated inside cholesterol-rich microdomains called lipid rafts, which, if disrupted or destroyed, could lead to a perturbation of lytic mechanism. Previous studies also reported that leptin could induce membrane remodeling. In this context, we studied the effect of membrane remodeling in lytic activity modulation induced by leptin. Thus, primary mouse splenocytes were incubated with methyl-β-cyclodextrin (β-MCD), a lipid rafts disrupting agent, cholesterol, a major component of cell membranes, or ursodeoxycholic acid (UDCA), a membrane stabilizer agent for 1 h. These treatments were followed by splenocyte incubation with leptin (absence, 10 and 100 ng/ml). Unlike β-MCD or cholesterol, UDCA was able to block leptin lytic induction. This result suggests that leptin increased the lytic activity of primary spleen cells against syngenic EO771 mammary cancer cells independently from lipid rafts but may involve membrane fluidity. Furthermore, natural killer cells were shown to be involved in the splenocyte lytic activity. To our knowledge it is the first publication in primary culture that provides the link between leptin lytic modulation and membrane remodeling. J. Cell. Physiol. 232: 101-109, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Aurore Collin
- Clermont Université, Université d'Auvergne, UFR Pharmacie, UMR 1019, Unité de Nutrition Humaine, Equipe ECREIN, CLARA, Clermont-Ferrand, France. .,INRA, UMR 1019, Unité de Nutrition Humaine, CRNH Auvergne, Clermont-Ferrand, France.
| | - Audrey Noacco
- Clermont Université, Université d'Auvergne, UFR Pharmacie, UMR 1019, Unité de Nutrition Humaine, Equipe ECREIN, CLARA, Clermont-Ferrand, France.,INRA, UMR 1019, Unité de Nutrition Humaine, CRNH Auvergne, Clermont-Ferrand, France
| | - Jérémie Talvas
- Clermont Université, Université d'Auvergne, UFR Pharmacie, UMR 1019, Unité de Nutrition Humaine, Equipe ECREIN, CLARA, Clermont-Ferrand, France.,INRA, UMR 1019, Unité de Nutrition Humaine, CRNH Auvergne, Clermont-Ferrand, France
| | - Florence Caldefie-Chézet
- Clermont Université, Université d'Auvergne, UFR Pharmacie, UMR 1019, Unité de Nutrition Humaine, Equipe ECREIN, CLARA, Clermont-Ferrand, France.,INRA, UMR 1019, Unité de Nutrition Humaine, CRNH Auvergne, Clermont-Ferrand, France
| | - Marie-Paule Vasson
- Clermont Université, Université d'Auvergne, UFR Pharmacie, UMR 1019, Unité de Nutrition Humaine, Equipe ECREIN, CLARA, Clermont-Ferrand, France.,INRA, UMR 1019, Unité de Nutrition Humaine, CRNH Auvergne, Clermont-Ferrand, France.,Centre Jean-Perrin, CHU Gabriel-Montpied, Unité de Nutrition, Clermont-Ferrand, France
| | - Marie-Chantal Farges
- Clermont Université, Université d'Auvergne, UFR Pharmacie, UMR 1019, Unité de Nutrition Humaine, Equipe ECREIN, CLARA, Clermont-Ferrand, France.,INRA, UMR 1019, Unité de Nutrition Humaine, CRNH Auvergne, Clermont-Ferrand, France
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De Bock M, Van Haver V, Vandenbroucke RE, Decrock E, Wang N, Leybaert L. Into rather unexplored terrain-transcellular transport across the blood-brain barrier. Glia 2016; 64:1097-123. [DOI: 10.1002/glia.22960] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 11/16/2015] [Accepted: 12/03/2015] [Indexed: 01/22/2023]
Affiliation(s)
- Marijke De Bock
- Physiology Group, Department of Basic Medical Sciences; Ghent University; Ghent Belgium
| | - Valérie Van Haver
- Physiology Group, Department of Basic Medical Sciences; Ghent University; Ghent Belgium
| | - Roosmarijn E. Vandenbroucke
- Inflammation Research Center, VIB; Ghent Belgium
- Department of Biomedical Molecular Biology; Ghent University; Ghent Belgium
| | - Elke Decrock
- Physiology Group, Department of Basic Medical Sciences; Ghent University; Ghent Belgium
| | - Nan Wang
- Physiology Group, Department of Basic Medical Sciences; Ghent University; Ghent Belgium
| | - Luc Leybaert
- Physiology Group, Department of Basic Medical Sciences; Ghent University; Ghent Belgium
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13
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Promising approaches to circumvent the blood-brain barrier: progress, pitfalls and clinical prospects in brain cancer. Ther Deliv 2015; 6:989-1016. [PMID: 26488496 DOI: 10.4155/tde.15.48] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Brain drug delivery is a major challenge for therapy of central nervous system (CNS) diseases. Biochemical modifications of drugs or drug nanocarriers, methods of local delivery, and blood-brain barrier (BBB) disruption with focused ultrasound and microbubbles are promising approaches which enhance transport or bypass the BBB. These approaches are discussed in the context of brain cancer as an example in CNS drug development. Targeting to receptors enabling transport across the BBB offers noninvasive delivery of small molecule and biological cancer therapeutics. Local delivery methods enable high dose delivery while avoiding systemic exposure. BBB disruption with focused ultrasound and microbubbles offers local and noninvasive treatment. Clinical trials show the prospects of these technologies and point to challenges for the future.
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Role of Astrocytes in Leptin Signaling. J Mol Neurosci 2015; 56:829-839. [PMID: 25687329 DOI: 10.1007/s12031-015-0518-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Accepted: 02/04/2015] [Indexed: 12/11/2022]
Abstract
To test the hypothesis that astrocytic leptin signaling induces an overall potentiation of the neuronal response to leptin, we generated a new line of astrocyte-specific leptin receptor knockout (ALKO-Δ1) mice in which no leptin receptor is expressed in astrocytes. Corresponding to cell-specific Cre recombinase expression in hypothalamic astrocytes but not neurons, this new strain of ALKO mice had attenuated pSTAT3 signaling in the arcuate nucleus of the hypothalamus 30 min after intracerebroventricular delivery of leptin. In response to high-fat diet for 2 months, the ALKO mice showed a greater increase of percent fat and blood leptin concentration. This coincided with a mild reactive gliosis in the hypothalamus. Overall, the absence of leptin receptors in astrocytes attenuated hypothalamic pSTAT3 signaling, induced a mild reactive morphology, and promoted the development of diet-induced obesity. We conclude that leptin signaling in astrocytes is essential for the homeostasis of neuroendocrine regulation in obesity.
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15
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Hsuchou H, Jayaram B, Kastin AJ, Wang Y, Ouyang S, Pan W. Endothelial cell leptin receptor mutant mice have hyperleptinemia and reduced tissue uptake. J Cell Physiol 2013; 228:1610-6. [PMID: 23359322 DOI: 10.1002/jcp.24325] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 01/14/2013] [Indexed: 11/10/2022]
Abstract
Hyperleptinemia is usually associated with obesity and leptin resistance. Endothelial cell leptin receptor knockout (ELKO) mice without a signaling membrane-bound leptin receptor in endothelia, however, have profound hyperleptinemia without signs of leptin resistance. Leptin mRNA in adipose tissue was unchanged. To test the hypothesis that the ELKO mutation results in delayed degradation and slowed excretion, we determined the kinetics of leptin transfer in groups of ELKO and wildtype mice after intravenous bolus injection of (125) I-leptin and the reference substance (131) I-albumin. The degradation pattern of (125) I-leptin in serum and brain homogenates at different time points between 10 and 60 min was measured by HPLC and acid precipitation. Although ELKO mice had reduced uptake of (125) I-leptin uptake by the brain and several peripheral organs, leptin was more stable in blood and tissue. There was no change in the rate of renal excretion. ELISA showed that serum soluble leptin receptor, known to antagonize leptin transport, had a 400-fold increase, probably contributing to the hyperleptinemia and reduced tissue uptake. Thus, the ELKO mutation unexpectedly increased the stability of leptin but suppressed its tissue uptake. These changes probably contribute to the known partial resistance of the ELKO mice to diet-induced obesity.
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Affiliation(s)
- Hung Hsuchou
- Blood-Brain Barrier Group, Pennington Biomedical Research Center, Baton Rouge, Louisiana 70808, USA
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16
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Hsuchou H, Mishra PK, Kastin AJ, Wu X, Wang Y, Ouyang S, Pan W. Saturable leptin transport across the BBB persists in EAE mice. J Mol Neurosci 2013; 51:364-70. [PMID: 23504255 DOI: 10.1007/s12031-013-9993-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 03/03/2013] [Indexed: 02/03/2023]
Abstract
We have shown that mice with experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis, have upregulated leptin receptor expression in reactive astrocytes of the hippocampus, a region involved in sickness behavior. Leptin can exacerbate EAE when its serum concentration is high. Although leptin receptors in astrocytes modulate leptin transport across cultured endothelial cell monolayers, it is not known how leptin transport in EAE mice is regulated. Here, we determined brain and cervical spinal cord uptake of leptin in early and recovery stages of EAE, after either intravenous delivery or in situ brain perfusion of (125)I-leptin and the vascular marker (131)I-albumin. While increased vascular space and general blood-brain barrier (BBB) permeability after EAE were expected, the specific saturable transport system for leptin crossing the BBB also persisted. Moreover, there was upregulation of leptin transport in hippocampus and cervical spinal cord in the early stage of EAE, shown by higher leptin uptake in these regions and by competitive inhibition with coadministered excess unlabeled leptin. We conclude that EAE induced a time- and region-specific increase of leptin transport. The results provide a link between circulating leptin and enhanced leptin signaling that may play a crucial role in disease progression.
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Affiliation(s)
- Hung Hsuchou
- Blood-Brain Barrier Group, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA
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17
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Pan W, Stone KP, Hsuchou H, Manda VK, Zhang Y, Kastin AJ. Cytokine signaling modulates blood-brain barrier function. Curr Pharm Des 2013; 17:3729-40. [PMID: 21834767 DOI: 10.2174/138161211798220918] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/30/2011] [Accepted: 09/26/2011] [Indexed: 02/06/2023]
Abstract
The blood-brain barrier (BBB) provides a vast interface for cytokines to affect CNS function. The BBB is a target for therapeutic intervention. It is essential, therefore, to understand how cytokines interact with each other at the level of the BBB and how secondary signals modulate CNS functions beyond the BBB. The interactions between cytokines and lipids, however, have not been fully addressed at the level of the BBB. Here, we summarize current understanding of the localization of cytokine receptors and transporters in specific membrane microdomains, particularly lipid rafts, on the luminal (apical) surface of the microvascular endothelial cells composing the BBB. We then illustrate the clinical context of cytokine effects on the BBB by neuroendocrine regulation and amplification of inflammatory signals. Two unusual aspects discussed are signaling crosstalk by different classes of cytokines and genetic regulation of drug efflux transporters. We also introduce a novel area of focus on how cytokines may act through nuclear hormone receptors to modulate efflux transporters and other targets. A specific example discussed is the ATP-binding cassette transporter-1 (ABCA-1) that regulates lipid metabolism. Overall, cytokine signaling at the level of the BBB is a crucial feature of the dynamic regulation that can rapidly change BBB function and affect brain health and disease.
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Affiliation(s)
- Weihong Pan
- Blood-Brain Barrier Group, Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA
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18
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Jayaram B, Khan RS, Kastin AJ, Hsuchou H, Wu X, Pan W. Protective role of astrocytic leptin signaling against excitotoxicity. J Mol Neurosci 2012. [PMID: 23180096 DOI: 10.1007/s12031-012-9924-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Both proconvulsive and anticonvulsive roles of leptin have been reported, suggesting cell-specific actions of leptin in different models of seizure and epilepsy. The goal of our study was to determine the regulation and function of astrocytic leptin receptors in a mouse model of epilepsy and glutamate-induced cytotoxicity. We show that in pilocarpine-challenged mice developing epilepsy with recurrent seizures after a latent period of 2 weeks, hippocampal leptin receptor (ObR) immunofluorescence was increased at 6 weeks. This was more pronounced in astrocytes than in neurons. In cultured astrocytes, glutamate increased ObRa and ObRb expression, whereas leptin pretreatment attenuated glial cytotoxicity by excess glutamate, reflected by better preserved adenosine triphosphate production. The protective role of astrocytic leptin signaling is further supported by the higher lethality of the astrocyte-specific leptin receptor knockout mice in the initial phase of seizure production. Thus, leptin signaling in astrocytes plays a protective role against seizure, and the effects are at least partially mediated by attenuation of glutamate toxicity. Astrocytic leptin signaling, therefore, may be a novel therapeutic target.
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Affiliation(s)
- Bhavaani Jayaram
- Blood-Brain Barrier Group, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
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19
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Walduck AK, Becher D. Leptin, CD4(+) T(reg) and the prospects for vaccination against H. pylori infection. Front Immunol 2012; 3:316. [PMID: 23087691 PMCID: PMC3470998 DOI: 10.3389/fimmu.2012.00316] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 09/24/2012] [Indexed: 12/15/2022] Open
Abstract
Helicobacter pylori infection induces chronic inflammation which is characterized not only by infiltrations of inflammatory cells such as neutrophils and CD4+ T cells, but also significant populations of regulatory T cells (Treg). These cells are important for disease pathogenesis because they are believed to contribute to the persistence of the infection. Despite encouraging results in animal models, the prospects for an effective H. pylori vaccine are currently poor because of generally disappointing results in preclinical and phase 1 trials. As a result, a current major focus of basic research on vaccination is to better understand the mechanisms regulating the inflammatory response with the view it can inform future vaccine design. Our studies in this area have focused on gastric CD4+ Treg in vaccinated mice, and raised the hypothesis that adipokines in particular leptin are involved the establishment of a protective gastric immune response. Here we discuss the hypothesis that vaccination deregulates Treg responses in the gastric mucosa, and that this process is mediated by leptin. We propose that reduced suppression permits a protective sub population of H. pylori-specific CD4+ T cells to exert protective effects, presumably via the gastric epithelium. Evidence from the literature and experimental approaches will be discussed.
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Affiliation(s)
- Anna K Walduck
- Department of Microbiology and Immunology, University of Melbourne Parkville, VIC, Australia
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20
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Hsuchou H, Kastin AJ, Mishra PK, Pan W. C-reactive protein increases BBB permeability: implications for obesity and neuroinflammation. Cell Physiol Biochem 2012; 30:1109-19. [PMID: 23018453 DOI: 10.1159/000343302] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/14/2012] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND/AIMS Acute phase C-reactive protein (CRP), elevated in obesity and inflammation, is a major binding protein for leptin. It is thought that CRP contributes to leptin resistance by preventing leptin from crossing the blood-brain barrier (BBB). Here we determined how CRP interacts with the BBB and whether it deters leptin from reaching CNS targets. METHODS BBB permeability, compartmental distribution, tracer stability, and expression of tight junction protein and inflammatory marker were determined. RESULTS CRP was stable in blood, but did not permeate the BBB in trace amounts. However, it increased paracellular permeability at a higher dose. Agouti viable (A(vy)) mice with adult-onset obesity show higher CRP entry into the brain. CRP did not permeate hCMEC/D3 cells nor change zona occludin-1 or cyclooxygenase-2 expression. An intermediate dose of CRP had no effect on leptin transport across the BBB after co-treatment. Thus, acute interactions between CRP and leptin at the BBB level were negligible and did not explain the leptin resistance seen in obesity. CONCLUSIONS The interactions of CRP and the BBB are a two-phase process, with increased paracellular permeability at a high dose that enables its entry into the CNS and serves to induce reactive gliosis and impair CNS function.
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Affiliation(s)
- Hung Hsuchou
- Blood-Brain Barrier Group, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
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21
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Abstract
Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disorder affecting motoneurons. Mutations in angiogenin, encoding a member of the pancreatic RNase A superfamily, segregate with ALS. We previously demonstrated that angiogenin administration shows promise as a neuroprotective therapeutic in studies using transgenic ALS mice and primary motoneuron cultures. Its mechanism of action and target cells in the spinal cord, however, are largely unknown. Using mixed motoneuron cultures, motoneuron-like NSC34 cells, and primary astroglia cultures as model systems, we here demonstrate that angiogenin is a neuronally secreted factor that is endocytosed by astroglia and mediates neuroprotection in paracrine. We show that wild-type angiogenin acts unidirectionally to induce RNA cleavage in astroglia, while the ALS-associated K40I mutant is also secreted and endocytosed, but fails to induce RNA cleavage. Angiogenin uptake into astroglia requires heparan sulfate proteoglycans, and engages clathrin-mediated endocytosis. We show that this uptake mechanism exists for mouse and human angiogenin, and delivers a functional RNase output. Moreover, we identify syndecan 4 as the angiogenin receptor mediating the selective uptake of angiogenin into astroglia. Our data provide new insights into the paracrine activities of angiogenin in the nervous system, and further highlight the critical role of non-neuronal cells in the pathogenesis of ALS.
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22
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Wu X, Hsuchou H, Kastin AJ, Mishra PK, Pan W. Upregulation of astrocytic leptin receptor in mice with experimental autoimmune encephalomyelitis. J Mol Neurosci 2012; 49:446-56. [PMID: 22684620 DOI: 10.1007/s12031-012-9825-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 05/28/2012] [Indexed: 01/02/2023]
Abstract
The detrimental role of leptin in experimental autoimmune encephalomyelitis (EAE) is opposite to its neuroprotective role in other neuropathologies. We hypothesize that a shifted cellular distribution of leptin receptors underlies the differential effects of leptin. A robust increase of ObR immunoreactivity was seen along glial fibrillary acidic protein (GFAP)(+) intermediate filaments in reactive astrocytes in the hippocampus and hypothalamus of mice with EAE. Although astrocyte-specific GFAP mRNA and protein were both increased, ObRa mRNA was elevated only after resolution of EAE symptoms, and ObRb mRNA was even decreased at the peak time of symptoms of EAE. A cell type-specific action of leptin may underlie its differential effects.
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Affiliation(s)
- Xiaojun Wu
- Blood-Brain Barrier Group, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
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23
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Pan W, Hsuchou H, Cornelissen-Guillaume GG, Jayaram B, Wang Y, Tu H, Halberg F, Wu X, Chua SC, Kastin AJ. Endothelial leptin receptor mutation provides partial resistance to diet-induced obesity. J Appl Physiol (1985) 2012; 112:1410-8. [PMID: 22323652 DOI: 10.1152/japplphysiol.00590.2011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Leptin, a polypeptide hormone produced mainly by adipocytes, has diverse effects in both the brain and peripheral organs, including suppression of feeding. Other than mediating leptin transport across the blood-brain barrier, the role of the endothelial leptin receptor remains unclear. We recently generated a mutant mouse strain lacking endothelial leptin receptor signaling, and showed that there is an increased uptake of leptin by brain parenchyma after its delivery by in situ brain perfusion. Here, we tested the hypothesis that endothelial leptin receptor mutation confers partial resistance to diet-induced obesity. These ELKO mice had similar body weight and percent fat as their wild-type littermates when fed with rodent chow, but blood concentrations of leptin were significantly elevated. In response to a high-fat diet, wild-type mice had a greater gain of body weight and fat than ELKO mice. As shown by metabolic chamber measurement, the ELKO mice had higher oxygen consumption, carbon dioxide production, and heat dissipation, although food intake was similar to that of the wild-type mice and locomotor activity was even reduced. This indicates that the partial resistance to diet-induced obesity was mediated by higher metabolic activity in the ELKO mice. Since neuronal leptin receptor knockout mice show obesity and diabetes, the results suggest that endothelial leptin signaling shows opposite effects from that of neuronal leptin signaling, with a facilitatory role in diet-induced obesity.
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Affiliation(s)
- Weihong Pan
- Blood-Brain Barrier Group, Pennington Biomedical Research Center, 6400 Perkins Rd., Baton Rouge, LA 70808, USA.
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Perni S, Calzuola I, Gianfranceschi GL, Giavarini F, Lucci P, Pacetti D, Frega NG, Marsili V. Biochemical and mass spectrometry recognition of phospholipid-peptide complexes in wheat sprouts extract. J Pept Sci 2011; 17:744-50. [DOI: 10.1002/psc.1397] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 06/14/2011] [Accepted: 06/23/2011] [Indexed: 11/06/2022]
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Cao YB, Xue JL, Wu LY, Jiang W, Hu PN, Zhu J. The detection of 3 leptin receptor isoforms in crucian carp gill and the influence of fasting and hypoxia on their expression. Domest Anim Endocrinol 2011; 41:74-80. [PMID: 21741575 DOI: 10.1016/j.domaniend.2011.04.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2011] [Revised: 03/30/2011] [Accepted: 04/27/2011] [Indexed: 12/31/2022]
Abstract
To understand leptin signaling pathway in the crucian carp (Carassius carassius), we cloned 3 leptin receptor isoform complementary DNAs (ie, the long form [cclpr-L], the short form [cclpr-s1], and the secreted form [cclpr-s2]). Variant cclpr-L had a 3,255-bp open reading frame and a complete intracellular domain with box 1 and box 2 consensus sequences. By contrast, cclpr-s1 contained only 4 amino acids in its intracellular domain, without the "box 1" motif, which is conserved among membrane-bound leptin receptor short isoforms in mammals. Variant cclpr-s2 had no transmembrane domain, suggesting that it is a soluble form of the receptor, and alternative splicing of cclpr-s2 mRNA employs a different mechanism for the generation of soluble leptin receptor by intron retention. The fasting-treated fish showed significantly lower cclpr-L mRNA levels in gill tissue than the control group, whereas cclpr-s2 mRNA levels did not vary significantly among the groups. Treatment with hypoxia significantly increased mRNA levels of both cclpr-L and cclpr-s2 in gill tissue. To our knowledge, this is the first study of leptin receptor isoforms expression in teleosts.
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Affiliation(s)
- Y-B Cao
- College of Chemistry and Life Science, Zhejiang Normal University, Jinhua Zhejiang, China.
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26
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Hsuchou H, Kastin AJ, Tu H, Markadakis EN, Stone KP, Wang Y, Heymsfield SB, Chua SS, Obici S, Magrisso IJ, Pan W. Effects of cell-type specific leptin receptor mutation on leptin transport across the BBB. Peptides 2011; 32:1392-9. [PMID: 21616110 PMCID: PMC3137692 DOI: 10.1016/j.peptides.2011.05.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 05/09/2011] [Accepted: 05/09/2011] [Indexed: 11/19/2022]
Abstract
The functions of leptin receptors (LRs) are cell-type specific. At the blood-brain barrier, LRs mediate leptin transport that is essential for its CNS actions, and both endothelial and astrocytic LRs may be involved. To test this, we generated endothelia specific LR knockout (ELKO) and astrocyte specific LR knockout (ALKO) mice. ELKO mice were derived from a cross of Tie2-cre recombinase mice with LR-floxed mice, whereas ALKO mice were generated by a cross of GFAP-cre with LR-floxed mice, yielding mutant transmembrane LRs without signaling functions in endothelial cells and astrocytes, respectively. The ELKO mutation did not affect leptin half-life in blood or apparent influx rate to the brain and spinal cord, though there was an increase of brain parenchymal uptake of leptin after in situ brain perfusion. Similarly, the ALKO mutation did not affect blood-brain barrier permeation of leptin or its degradation in blood and brain. The results support our observation from cellular studies that membrane-bound truncated LRs are fully efficient in transporting leptin, and that basal levels of astrocytic LRs do not affect leptin transport across the endothelial monolayer. Nonetheless, the absence of leptin signaling at the BBB appears to enhance the availability of leptin to CNS parenchyma. The ELKO and ALKO mice provide new models to determine the dynamic regulation of leptin transport in metabolic and inflammatory disorders where cellular distribution of LRs is shifted.
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Affiliation(s)
- Hung Hsuchou
- Pennington Biomedical Research Center, Baton Rouge, LA 70808
| | - Abba J. Kastin
- Pennington Biomedical Research Center, Baton Rouge, LA 70808
| | - Hong Tu
- Pennington Biomedical Research Center, Baton Rouge, LA 70808
| | | | | | - Yuping Wang
- Pennington Biomedical Research Center, Baton Rouge, LA 70808
| | | | | | - Silvana Obici
- Obesity Research Center, University of Cincinnati, Cincinnati, Ohio 45237
| | - I. Jack Magrisso
- Obesity Research Center, University of Cincinnati, Cincinnati, Ohio 45237
| | - Weihong Pan
- Pennington Biomedical Research Center, Baton Rouge, LA 70808
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27
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Pan W, Hsuchou H, Xu C, Wu X, Bouret SG, Kastin AJ. Astrocytes modulate distribution and neuronal signaling of leptin in the hypothalamus of obese A vy mice. J Mol Neurosci 2010; 43:478-84. [PMID: 21086065 DOI: 10.1007/s12031-010-9470-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2010] [Accepted: 10/28/2010] [Indexed: 02/07/2023]
Abstract
We tested the hypothesis that astrocytic activity modulates neuronal uptake and signaling of leptin in the adult-onset obese agouti viable yellow (A vy) mouse. In the immunohistochemical study, A vy mice were pretreated with the astrocyte metabolic inhibitor fluorocitrate or phosphate-buffered saline (PBS) vehicle intracerebroventricularly (icv) followed 1 h later by Alexa568-leptin. Confocal microscopy showed that fluorocitrate pretreatment reduced astrocytic uptake of Alexa568-leptin 30 min after icv while increasing neuronal uptake in the arcuate nucleus and dorsomedial hypothalamus. Fluorocitrate also induced mild astrogliosis and moderately increased pSTAT3 immunopositive neurons in response to Alexa568-leptin in the dorsomedial hypothalamus. In the Western blotting study, A vy mice were pretreated with either PBS or fluorocitrate, and received PBS or leptin 1 h later followed by determination of pSTAT3 and GFAP expression an additional 30 min afterward. The results show that fluorocitrate induced a mild pSTAT3 activation but attenuated leptin-induced pSTAT3 activation and decreased GFAP expression independently of leptin treatment. We conclude that inhibition of astrocytic activity resulted in enhanced neuronal leptin uptake and signaling. This suggests opposite roles of astrocytes and neurons in leptin's actions in the A vy mouse with adult-onset obesity.
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Affiliation(s)
- Weihong Pan
- Blood-Brain Barrier Group, Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
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