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Szanda G, Jourdan T, Wisniewski É, Cinar R, Godlewski G, Rajki A, Liu J, Chedester L, Szalai B, Tóth AD, Soltész-Katona E, Hunyady L, Inoue A, Horváth VB, Spät A, Tam J, Kunos G. Cannabinoid receptor type 1 (CB 1R) inhibits hypothalamic leptin signaling via β-arrestin1 in complex with TC-PTP and STAT3. iScience 2023; 26:107207. [PMID: 37534180 PMCID: PMC10392084 DOI: 10.1016/j.isci.2023.107207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 05/20/2023] [Accepted: 06/21/2023] [Indexed: 08/04/2023] Open
Abstract
Molecular interactions between anorexigenic leptin and orexigenic endocannabinoids, although of great metabolic significance, are not well understood. We report here that hypothalamic STAT3 signaling in mice, initiated by physiological elevations of leptin, is diminished by agonists of the cannabinoid receptor 1 (CB1R). Measurement of STAT3 activation by semi-automated confocal microscopy in cultured neurons revealed that this CB1R-mediated inhibition requires both T cell protein tyrosine phosphatase (TC-PTP) and β-arrestin1 but is independent of changes in cAMP. Moreover, β-arrestin1 translocates to the nucleus upon CB1R activation and binds both STAT3 and TC-PTP. Consistently, CB1R activation failed to suppress leptin signaling in β-arrestin1 knockout mice in vivo, and in neural cells deficient in CB1R, β-arrestin1 or TC-PTP. Altogether, CB1R activation engages β-arrestin1 to coordinate the TC-PTP-mediated inhibition of the leptin-evoked neuronal STAT3 response. This mechanism may restrict the anorexigenic effects of leptin when hypothalamic endocannabinoid levels rise, as during fasting or in diet-induced obesity.
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Affiliation(s)
- Gergő Szanda
- Department of Physiology, Semmelweis University Medical School, 1094 Budapest, Hungary
- ELKH-SE Laboratory of Molecular Physiology Research Group, Eötvös Loránd Research Network, 1094 Budapest, Hungary
| | - Tony Jourdan
- INSERM Center Lipids, Nutrition, Cancer LNC U1231, 21000 Dijon, France
| | - Éva Wisniewski
- Department of Physiology, Semmelweis University Medical School, 1094 Budapest, Hungary
| | - Resat Cinar
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Grzegorz Godlewski
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anikó Rajki
- Department of Physiology, Semmelweis University Medical School, 1094 Budapest, Hungary
- ELKH-SE Laboratory of Molecular Physiology Research Group, Eötvös Loránd Research Network, 1094 Budapest, Hungary
| | - Jie Liu
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lee Chedester
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bence Szalai
- Department of Physiology, Semmelweis University Medical School, 1094 Budapest, Hungary
| | - András Dávid Tóth
- Department of Physiology, Semmelweis University Medical School, 1094 Budapest, Hungary
- Department of Internal Medicine and Haematology, Semmelweis University, 1085 Budapest, Hungary
| | - Eszter Soltész-Katona
- Department of Physiology, Semmelweis University Medical School, 1094 Budapest, Hungary
- Institute of Enzymology, Research Centre for Natural Sciences, Centre of Excellence of the Hungarian Academy of Sciences, 1117 Budapest, Hungary
| | - László Hunyady
- Department of Physiology, Semmelweis University Medical School, 1094 Budapest, Hungary
- Institute of Enzymology, Research Centre for Natural Sciences, Centre of Excellence of the Hungarian Academy of Sciences, 1117 Budapest, Hungary
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Viktória Bea Horváth
- Department of Physiology, Semmelweis University Medical School, 1094 Budapest, Hungary
| | - András Spät
- Department of Physiology, Semmelweis University Medical School, 1094 Budapest, Hungary
| | - Joseph Tam
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - George Kunos
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
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Funcke JB, Moepps B, Roos J, von Schnurbein J, Verstraete K, Fröhlich-Reiterer E, Kohlsdorf K, Nunziata A, Brandt S, Tsirigotaki A, Dansercoer A, Suppan E, Haris B, Debatin KM, Savvides SN, Farooqi IS, Hussain K, Gierschik P, Fischer-Posovszky P, Wabitsch M. Rare Antagonistic Leptin Variants and Severe, Early-Onset Obesity. N Engl J Med 2023; 388:2253-2261. [PMID: 37314706 DOI: 10.1056/nejmoa2204041] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Hormone absence or inactivity is common in congenital disease, but hormone antagonism remains controversial. Here, we characterize two novel homozygous leptin variants that yielded antagonistic proteins in two unrelated children with intense hyperphagia, severe obesity, and high circulating levels of leptin. Both variants bind to the leptin receptor but trigger marginal, if any, signaling. In the presence of nonvariant leptin, the variants act as competitive antagonists. Thus, treatment with recombinant leptin was initiated at high doses, which were gradually lowered. Both patients eventually attained near-normal weight. Antidrug antibodies developed in the patients, although they had no apparent effect on efficacy. No severe adverse events were observed. (Funded by the German Research Foundation and others.).
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Affiliation(s)
- Jan-Bernd Funcke
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Barbara Moepps
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Julian Roos
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Julia von Schnurbein
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Kenneth Verstraete
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Elke Fröhlich-Reiterer
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Katja Kohlsdorf
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Adriana Nunziata
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Stephanie Brandt
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Alexandra Tsirigotaki
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Ann Dansercoer
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Elisabeth Suppan
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Basma Haris
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Klaus-Michael Debatin
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Savvas N Savvides
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - I Sadaf Farooqi
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Khalid Hussain
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Peter Gierschik
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Pamela Fischer-Posovszky
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
| | - Martin Wabitsch
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine (J.-B.F., J.R., J.S., K.K., A.N., S.B., P.F.-P., M.W.), the Institute of Experimental and Clinical Pharmacology, Toxicology, and Pharmacology of Natural Products (B.M., P.G.), and the Department of Pediatrics and Adolescent Medicine (K.-M.D.), Ulm University Medical Center, Ulm, Germany; the Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas (J.-B.F.); the Unit for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium (K.V., A.T., A.D., S.N.S.); the Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria (E.F.-R., E.S.); the Division of Endocrinology, Department of Pediatrics, Sidra Medicine, Doha, Qatar (B.H., K.H.); and Wellcome Trust-Medical Research Council Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, United Kingdom (I.S.F.)
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Simien JM, Orellana GE, Phan HTN, Hu Y, Kurth EA, Ruf C, Kricek F, Wang Q, Smrcka AV, Haglund E. A Small Contribution to a Large System: The Leptin Receptor Complex. J Phys Chem B 2023; 127:2457-2465. [PMID: 36912891 DOI: 10.1021/acs.jpcb.3c01090] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Obesity is a classified epidemic, increasing the risk of secondary diseases such as diabetes, inflammation, cardiovascular disease, and cancer. The pleiotropic hormone leptin is the proposed link for the gut-brain axis controlling nutritional status and energy expenditure. Research into leptin signaling provides great promise toward discovering therapeutics for obesity and its related diseases targeting leptin and its cognate leptin receptor (LEP-R). The molecular basis underlying the human leptin receptor complex assembly remains obscure, due to the lack of structural information regarding the biologically active complex. In this work, we investigate the proposed receptor binding sites in human leptin utilizing designed antagonist proteins combined with AlphaFold predictions. Our results show that binding site I has a more intricate role in the active signaling complex than previously described. We hypothesize that the hydrophobic patch in this region engages a third receptor forming a higher-order complex, or a new LEP-R binding site inducing allosteric rearrangement.
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Affiliation(s)
- Jennifer M Simien
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Grace E Orellana
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Hoa T N Phan
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Yao Hu
- Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Emily A Kurth
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Christine Ruf
- NBS-C BioScience & Consulting GmbH, Vienna, 1230, Austria
| | - Franz Kricek
- NBS-C BioScience & Consulting GmbH, Vienna, 1230, Austria
| | - Qian Wang
- Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Alan V Smrcka
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Ellinor Haglund
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
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Lei MM, Dai ZC, Zhu HX, Chen R, Chen Z, Shao CR, Shi ZD. Impairment of testes development in Yangzhou ganders by augmentation of leptin receptor signaling. Theriogenology 2021; 171:94-103. [PMID: 34051590 DOI: 10.1016/j.theriogenology.2021.05.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/11/2021] [Accepted: 05/16/2021] [Indexed: 10/21/2022]
Abstract
The aim of this study was to determine the cellular and molecular mechanisms of leptin (LEP) and the leptin receptor (LEPR) in testicular development of prepubertal ganders. In an in vivo animal experiment, active immunization against LEPR severely depressed prepubertal testicular development by significantly reducing testicular weights at 200 and 227 days of age. The number of elongated spermatids in the seminiferous tubules was also significantly decreased by immunization with LEPR at ages of 200 and 227 days. Inhibition of testicular development by LEPR immunization was associated with decreases in LHR, StAR, 3β-HSD, CYP11A1, CYP17A1, and PRLR mRNA expression levels in testicular tissue, which resulted in a significant decrease in testosterone synthesis. In the in vitro experiments, the addition of LEP combined with anti-LEPR antibodies strengthened LEPR signal transduction, and inhibited significantly testosterone production in cultured Leydig cells isolated from prepubertal gander testes. The mRNA expression of LHR, StAR, 3β-HSD, CYP11A1, CYP17A1 also decreased significantly after treatment with LEP combined with anti-LEPR antibodies in cultured Leydig cells. These results suggest that anti-LEPR antibodies strengthen LEPR signaling transduction in the presence of LEP, and immunization against LEPR inhibited testes development and testosterone secretion in prepubertal ganders.
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Affiliation(s)
- M M Lei
- Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, 210014, China
| | - Z C Dai
- Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, 210014, China
| | - H X Zhu
- Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, 210014, China
| | - R Chen
- Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, 210014, China
| | - Z Chen
- Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, 210014, China
| | - C R Shao
- Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, 210014, China
| | - Z D Shi
- Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, 210014, China.
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Maekawa T, Nyu T, Mondarte EAQ, Tahara H, Suthiwanich K, Hayashi T. Visualization of molecular binding sites at the nanoscale in the lift-up mode by amplitude-modulation atomic force microscopy. NANOSCALE 2021; 13:4213-4220. [PMID: 33586723 DOI: 10.1039/d0nr06125e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We report a new approach to visualize the local distribution of molecular recognition sites with nanoscale resolution by amplitude-modulation atomic force microscopy. By integrating chemical modification of probes, photothermal excitation to drive a cantilever, and lift-up scanning over surface topography, we successfully visualized binding sites provided by streptavidin on a solid surface for biotin attached on an AFM probe. The optimization of measurement conditions was discussed in detail, and the application of the technique was verified with a different ligand-receptor system.
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Affiliation(s)
- Tatsuhiro Maekawa
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan.
| | - Takashi Nyu
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan.
| | - Evan Angelo Quimada Mondarte
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan.
| | - Hiroyuki Tahara
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan.
| | - Kasinan Suthiwanich
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan.
| | - Tomohiro Hayashi
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan. and JST-PRESTO, 4-1-8 Hon-cho, Kawaguchi, Saitama 332-0012, Japan
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6
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Cecon E, Lhomme T, Maurice T, Luka M, Chen M, Silva A, Wauman J, Zabeau L, Tavernier J, Prévot V, Dam J, Jockers R. Amyloid Beta Peptide Is an Endogenous Negative Allosteric Modulator of Leptin Receptor. Neuroendocrinology 2021; 111:370-387. [PMID: 32335558 DOI: 10.1159/000508105] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/23/2020] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Metabolic dysfunction is now recognized as a pivotal component of Alzheimer's disease (AD), the most common dementia worldwide. However, the precise molecular mechanisms linking metabolic dysfunction to AD remain elusive. OBJECTIVE Here, we investigated the direct impact of soluble oligomeric amyloid beta (Aβ) peptides, the main molecular hallmark of AD, on the leptin system, a major component of central energy metabolism regulation. METHODS We developed a new time-resolved fluorescence resonance energy transfer-based Aβ binding assay for the leptin receptor (LepR) and studied the effect of Aβ on LepR function in several in vitro assays. The in vivo effect of Aβ on LepR function was studied in an Aβ-specific AD mouse model and in pro-opiomelanocortin (POMC) neurons of the hypothalamic arcuate nucleus. RESULTS We revealed specific and high-affinity (Ki = 0.1 nM) binding of Aβ to LepR. Pharmacological characterization of this interaction showed that Aβ binds allosterically to the extracellular domain of LepR and negatively affects receptor function. Negative allosteric modulation of LepR by Aβ was detected at the level of signaling pathways (STAT-3, AKT, and ERK) in vitroand in vivo. Importantly, the leptin-induced response of POMC neurons, key players in the regulation of metabolic function, was completely abolished in the presence of Aβ. CONCLUSION Our data indicate that Aβ is a negative allosteric modulator of LepR, resulting in impaired leptin action, and qualify LepR as a new and direct target of Aβ oligomers. Preventing the interaction of Aβ with LepR might improve both the metabolic and cognitive dysfunctions in AD condition.
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Affiliation(s)
- Erika Cecon
- Institut Cochin, Université de Paris, CNRS, INSERM, Paris, France
| | - Tori Lhomme
- Univ. Lille, Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, EGID, DistAlz, Lille Neuroscience & Cognition, UMR-S 1172, Lille, France
| | - Tangui Maurice
- MMDN, University of Montpellier, EPHE, INSERM, UMR_S1198, Montpellier, France
| | - Marine Luka
- Institut Cochin, Université de Paris, CNRS, INSERM, Paris, France
| | - Min Chen
- Institut Cochin, Université de Paris, CNRS, INSERM, Paris, France
| | - Anisia Silva
- Institut Cochin, Université de Paris, CNRS, INSERM, Paris, France
| | - Joris Wauman
- VIB Center for Medical Biotechnology, Department of Biomolecular Medicine, University of Ghent, Ghent, Belgium
| | - Lennart Zabeau
- VIB Center for Medical Biotechnology, Department of Biomolecular Medicine, University of Ghent, Ghent, Belgium
| | - Jan Tavernier
- VIB Center for Medical Biotechnology, Department of Biomolecular Medicine, University of Ghent, Ghent, Belgium
| | - Vincent Prévot
- Univ. Lille, Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, EGID, DistAlz, Lille Neuroscience & Cognition, UMR-S 1172, Lille, France
| | - Julie Dam
- Institut Cochin, Université de Paris, CNRS, INSERM, Paris, France
| | - Ralf Jockers
- Institut Cochin, Université de Paris, CNRS, INSERM, Paris, France,
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7
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McGuckin MM, Giesy SL, Davis AN, Abyeta MA, Horst EA, Saed Samii S, Zang Y, Butler WR, Baumgard LH, McFadden JW, Boisclair YR. The acute phase protein orosomucoid 1 is upregulated in early lactation but does not trigger appetite-suppressing STAT3 signaling via the leptin receptor. J Dairy Sci 2020; 103:4765-4776. [PMID: 32229118 DOI: 10.3168/jds.2019-18094] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 01/09/2020] [Indexed: 12/13/2022]
Abstract
Dairy cows consume inadequate amounts of feed in early lactation and during conditions and diseases such as excessive fatness, heat stress, and infectious diseases. Affected cows often experience increases in plasma concentrations of acute phase proteins consistent with the negative effect of inflammation on appetite. The acute phase protein orosomucoid 1 (ORM1), also known as alpha-1-acid glycoprotein, was recently reported to reduce appetite in the mouse through its ability to bind the full-length leptin receptor (Ob-Rb) and activate appetite-suppressing signal transducer and activator of transcription 3 (STAT3) signaling. These observations raise the possibility that ORM1 exerts appetite-suppressing effects in dairy cattle during periods of increased inflammatory tone. The applicability of this model was assessed in 2 ways. First, we asked whether ORM1 is regulated during periods of inadequate appetite such as the transition from late pregnancy to early lactation and periods of increased inflammatory tone. Plasma ORM1 was invariant in late pregnancy but increased 2.5-fold between parturition and d 7 of lactation. Gene expression studies showed that liver was the major source of this elevation with little contribution by adipose tissue or mammary gland. Additional studies showed that plasma ORM1 was not increased further by excessive fatness or by reproductive dysfunction in early lactation and was completely unresponsive to inflammatory stimuli such as heat stress or intravascular administration of the endotoxin lipopolysaccharide during established lactation. Second, we tested the ability of ORM1 to trigger STAT3 signaling through Ob-Rb using Chinese hamster ovary K1 (CHO-K1) cells transfected with a STAT3 expression plasmid. In this configuration, CHO-K1 cells did not express Ob-Rb and were incapable of leptin-induced STAT3 phosphorylation. Leptin responsiveness was conferred by co-transfecting with bovine Ob-Rb, with leptin causing increases of 5.7-fold in STAT3 phosphorylation and 2.1-fold in the expression of the STAT3-dependent gene, SOCS3. In contrast, neither bovine or human ORM1 triggered STAT3 phosphorylation irrespective of dose and period of incubation tested. In summary, bovine ORM1 is not increased during periods of increased inflammatory tone except in early lactation and is incapable of Ob-Rb-dependent STAT3 signaling. Overall, these data are inconsistent with ORM1 mediating the appetite-suppressing effects of inflammation in cattle through Ob-Rb.
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Affiliation(s)
- M M McGuckin
- Department of Animal Science, Cornell University, Ithaca, NY 14853
| | - S L Giesy
- Department of Animal Science, Cornell University, Ithaca, NY 14853
| | - A N Davis
- Department of Animal Science, Cornell University, Ithaca, NY 14853
| | - M A Abyeta
- Department of Animal Science, Iowa State University, Ames 50011
| | - E A Horst
- Department of Animal Science, Iowa State University, Ames 50011
| | - S Saed Samii
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown 26505
| | - Y Zang
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown 26505
| | - W R Butler
- Department of Animal Science, Cornell University, Ithaca, NY 14853
| | - L H Baumgard
- Department of Animal Science, Iowa State University, Ames 50011
| | - J W McFadden
- Department of Animal Science, Cornell University, Ithaca, NY 14853
| | - Y R Boisclair
- Department of Animal Science, Cornell University, Ithaca, NY 14853.
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8
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Abstract
Leptin is a hormone that plays a major role as mediator of long-term regulation of energy balance, suppressing food intake, and stimulating weight loss. More recently, important physiological roles other than controlling appetite and energy expenditure have been suggested for leptin, including neuroendocrine, reparative, reproductive, and immune functions. These emerging peripheral roles let hypothesize that leptin can modulate also cancer progression. Indeed, many studies have demonstrated that elevated chronic serum concentrations of leptin, frequently seen in obese subjects, represent a stimulatory signal for tumor growth. Current knowledge indicates that also different non-tumoral cells resident in tumor microenvironment may respond to leptin creating a favorable soil for cancer cells. In addition, leptin is produced also within the tumor microenvironment creating the possibility for paracrine and autocrine action. In this review, we describe the main mechanisms that regulate peripheral leptin availability and how leptin can shape tumor microenvironment.
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9
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Zabeau L, Wauman J, Dam J, Van Lint S, Burg E, De Geest J, Rogge E, Silva A, Jockers R, Tavernier J. A novel leptin receptor antagonist uncouples leptin's metabolic and immune functions. Cell Mol Life Sci 2019; 76:1201-1214. [PMID: 30659329 PMCID: PMC11105424 DOI: 10.1007/s00018-019-03004-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 12/28/2018] [Accepted: 01/02/2019] [Indexed: 12/19/2022]
Abstract
Leptin links body energy stores to high energy demanding processes like reproduction and immunity. Based on leptin's role in autoimmune diseases and cancer, several leptin and leptin receptor (LR) antagonists have been developed, but these intrinsically lead to unwanted weight gain. Here, we report on the uncoupling of leptin's metabolic and immune functions based on the cross talk with the epidermal growth factor receptor (EGFR). We show that both receptors spontaneously interact and, remarkably, that this complex can partially overrule the lack of LR activation by a leptin antagonistic mutein. Moreover, this leptin mutant induces EGFR phosphorylation comparable to wild-type leptin. Exploiting this non-canonical leptin signalling pathway, we identified a camelid single-domain antibody that selectively inhibits this LR-EGFR cross talk without interfering with homotypic LR signalling. Administration in vivo showed that this single-domain antibody did not interfere with leptin's metabolic functions, but could reverse the leptin-driven protection against starvation-induced thymic and splenic atrophy. These findings offer new opportunities for the design and clinical application of selective leptin and LR antagonists that avoid unwanted metabolic side effects.
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Affiliation(s)
- Lennart Zabeau
- Faculty of Medicine and Health Sciences, VIB-UGent Center for Medical Biotechnology, Flanders Institute for Biotechnology, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium
| | - Joris Wauman
- Faculty of Medicine and Health Sciences, VIB-UGent Center for Medical Biotechnology, Flanders Institute for Biotechnology, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium
| | - Julie Dam
- Inserm U1016, CNRS UMR 8104, Univ. Paris Descartes, Sorbonne Paris Cité, Institut Cochin, 22 rue Méchain, 75014, Paris, France
| | - Sandra Van Lint
- Faculty of Medicine and Health Sciences, VIB-UGent Center for Medical Biotechnology, Flanders Institute for Biotechnology, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium
| | - Elianne Burg
- Faculty of Medicine and Health Sciences, VIB-UGent Center for Medical Biotechnology, Flanders Institute for Biotechnology, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium
| | - Jennifer De Geest
- Faculty of Medicine and Health Sciences, VIB-UGent Center for Medical Biotechnology, Flanders Institute for Biotechnology, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium
| | - Elke Rogge
- Faculty of Medicine and Health Sciences, VIB-UGent Center for Medical Biotechnology, Flanders Institute for Biotechnology, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium
| | - Anisia Silva
- Inserm U1016, CNRS UMR 8104, Univ. Paris Descartes, Sorbonne Paris Cité, Institut Cochin, 22 rue Méchain, 75014, Paris, France
| | - Ralf Jockers
- Inserm U1016, CNRS UMR 8104, Univ. Paris Descartes, Sorbonne Paris Cité, Institut Cochin, 22 rue Méchain, 75014, Paris, France
| | - Jan Tavernier
- Faculty of Medicine and Health Sciences, VIB-UGent Center for Medical Biotechnology, Flanders Institute for Biotechnology, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium.
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10
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Roujeau C, Jockers R, Dam J. Endospanin 1 Determines the Balance of Leptin-Regulated Hypothalamic Functions. Neuroendocrinology 2019; 108:132-141. [PMID: 30326479 DOI: 10.1159/000494557] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 10/16/2018] [Indexed: 11/19/2022]
Abstract
Endospanin 1 (Endo1), a protein encoded in humans by the same gene than the leptin receptor (ObR), and increased by diet-induced obesity, is an important regulator of ObR trafficking and cell surface exposure, determining leptin signaling strength. Defective intracellular trafficking of the leptin receptor to the neuronal plasma membrane has been proposed as a mechanism underlying the development of leptin resistance observed in human obesity. More recently, Endo1 has emerged as a mediator of "selective leptin resistance." The underlying mechanisms of the latter are not completely understood, but the possibility of differential activation of leptin signaling pathways was suggested among others. In this respect, the expression level of Endo1 is crucial for the appropriate balance between different leptin signaling pathways and leptin functions in the hypothalamus and is likely participating in selective leptin resistance for the control of energy and glucose homeostasis.
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Affiliation(s)
- Clara Roujeau
- Inserm U1016, CNRS UMR 8104, Institut Cochin, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Ralf Jockers
- Inserm U1016, CNRS UMR 8104, Institut Cochin, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Julie Dam
- Inserm U1016, CNRS UMR 8104, Institut Cochin, Université Paris Descartes, Sorbonne Paris Cité, Paris,
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11
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Dam J. [Traffic and signalisation of the leptin receptor]. Biol Aujourdhui 2018; 212:35-43. [PMID: 30362454 DOI: 10.1051/jbio/2018020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Indexed: 11/14/2022]
Abstract
Receptors are the master regulators conveying the information provided by the hormone from the extracellular environment to the intracellular milieu. As a result, the level of receptors at the cell surface can determine the signaling strength. Regulation of receptor trafficking to the cell surface or receptor retention processes in intracellular compartments are key mechanisms for leptin receptor (ObR) activity. An alteration of these mechanisms leads to the development of obesity. However, the canonical mechanism of plasma membrane receptors activation is challenged by the discovery that intracellular receptors also have their own signaling activity inside specific intracellular compartments. These intracellular receptors can trigger signaling that regulates a particular function, different from, or in continuity with, surface receptor signaling. We will address both these aspects by focusing particularly on the case of the leptin receptor (ObR), i.e., i) the regulation of its level of exposure to the cell surface and its impact on the development of obesity, and ii) the discovery of its location and signaling in some intracellular compartments.
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Affiliation(s)
- Julie Dam
- Institut Cochin, Inserm U1016, CNRS UMR 8104, Université Paris Descartes, Sorbonne Paris Cité, 22 Rue Méchain, 75014 Paris, France
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12
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Amphetamine Reverses Escalated Cocaine Intake via Restoration of Dopamine Transporter Conformation. J Neurosci 2017; 38:484-497. [PMID: 29175958 DOI: 10.1523/jneurosci.2604-17.2017] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/14/2017] [Accepted: 11/17/2017] [Indexed: 12/27/2022] Open
Abstract
Cocaine abuse disrupts dopamine system function, and reduces cocaine inhibition of the dopamine transporter (DAT), which results in tolerance. Although tolerance is a hallmark of cocaine addiction and a DSM-V criterion for substance abuse disorders, the molecular adaptations producing tolerance are unknown, and testing the impact of DAT changes on drug taking behaviors has proven difficult. In regard to treatment, amphetamine has shown efficacy in reducing cocaine intake; however, the mechanisms underlying these effects have not been explored. The goals of this study were twofold; we sought to (1) identify the molecular mechanisms by which cocaine exposure produces tolerance and (2) determine whether amphetamine-induced reductions in cocaine intake are connected to these mechanisms. Using cocaine self-administration and fast-scan cyclic voltammetry in male rats, we show that low-dose, continuous amphetamine treatment, during self-administration or abstinence, completely reversed cocaine tolerance. Amphetamine treatment also reversed escalated cocaine intake and decreased motivation to obtain cocaine as measured in a behavioral economics task, thereby linking tolerance to multiple facets of cocaine use. Finally, using fluorescence resonance energy transfer imaging, we found that cocaine tolerance is associated with the formation of DAT-DAT complexes, and that amphetamine disperses these complexes. In addition to extending our basic understanding of DATs and their role in cocaine reinforcement, we serendipitously identified a novel therapeutic target: DAT oligomer complexes. We show that dispersion of oligomers is concomitant with reduced cocaine intake, and propose that pharmacotherapeutics aimed at these complexes may have potential for cocaine addiction treatment.SIGNIFICANCE STATEMENT Tolerance to cocaine's subjective effects is a cardinal symptom of cocaine addiction and a DSM-V criterion for substance abuse disorders. However, elucidating the molecular adaptions that produce tolerance and determining its behavioral impact have proven difficult. Using cocaine self-administration in rats, we link tolerance to cocaine effects at the dopamine transporter (DAT) with aberrant cocaine-taking behaviors. Further, tolerance was associated with multi-DAT complexes, which formed after cocaine exposure. Treatment with amphetamine deconstructed DAT complexes, reversed tolerance, and decreased cocaine seeking. These data describe the behavioral consequence of cocaine tolerance, provide a putative mechanism for its development, and suggest that compounds that disperse DAT complexes may be efficacious treatments for cocaine addiction.
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13
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Camborde L, Jauneau A, Brière C, Deslandes L, Dumas B, Gaulin E. Detection of nucleic acid-protein interactions in plant leaves using fluorescence lifetime imaging microscopy. Nat Protoc 2017; 12:1933-1950. [PMID: 28837131 DOI: 10.1038/nprot.2017.076] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
DNA-binding proteins (DNA-BPs) and RNA-binding proteins (RNA-BPs) have critical roles in living cells in all kingdoms of life. Various experimental approaches exist for the study of nucleic acid-protein interactions in vitro and in vivo, but the detection of such interactions at the subcellular level remains challenging. Here we describe how to detect nucleic acid-protein interactions in plant leaves by using a fluorescence resonance energy transfer (FRET) approach coupled to fluorescence lifetime imaging microscopy (FLIM). Proteins of interest (POI) are tagged with a GFP and transiently expressed in plant cells to serve as donor fluorophore. After sample fixation and cell wall permeabilization, leaves are treated with Sytox Orange, a nucleic acid dye that can function as a FRET acceptor. Upon close association of the GFP-tagged POI with Sytox-Orange-stained nucleic acids, a substantial decrease of the GFP lifetime due to FRET between the donor and the acceptor can be monitored. Treatment with RNase before FRET-FLIM measurements allows determination of whether the POI associates with DNA and/or RNA. A step-by-step protocol is provided for sample preparation, data acquisition and analysis. We describe how to calibrate the equipment and include a tutorial explaining the use of the FLIM software. To illustrate our approach, we provide experimental procedures to detect the interaction between plant DNA and two proteins (the AeCRN13 effector from the oomycete Aphanomyces euteiches and the AtWRKY22 defensive transcription factor from Arabidopsis). This protocol allows the detection of protein-nucleic acid interactions in plant cells and can be completed in <2 d.
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Affiliation(s)
- Laurent Camborde
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS-Université Toulouse, Castanet-Tolosan, France
| | - Alain Jauneau
- CNRS, Plateforme Imagerie-Microscopie, Fédération de Recherche FR3450, Castanet-Tolosan, France
| | - Christian Brière
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS-Université Toulouse, Castanet-Tolosan, France
| | - Laurent Deslandes
- LIPM, Université de Toulouse, INRA, CNRS-Université Toulouse, Castanet-Tolosan, France
| | - Bernard Dumas
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS-Université Toulouse, Castanet-Tolosan, France
| | - Elodie Gaulin
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS-Université Toulouse, Castanet-Tolosan, France
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14
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Lao J, He H, Wang X, Wang Z, Song Y, Yang B, Ullahkhan N, Ge B, Huang F. Single-Molecule Imaging Demonstrates Ligand Regulation of the Oligomeric Status of CXCR4 in Living Cells. J Phys Chem B 2017; 121:1466-1474. [PMID: 28118546 DOI: 10.1021/acs.jpcb.6b10969] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The role of dimerization and oligomerization of G-protein-coupled receptors in their signal transduction is highly controversial. Delineating this issue can greatly facilitate rational drug design. With single-molecule imaging, we show that chemokine receptor CXCR4 exists mainly as a monomer in normal mammalian living cells and forms dimers and higher-order oligomers at a high expression level, such as in cancer cells. Chemotaxis tests demonstrate that the signal transduction activity of CXCR4 does not depend only on its expression level, indicating a close relation with the oligomeric status of CXCR4. Moreover, binding ligands can effectively upregulate or downregulate the oligomeric level of CXCR4, which suggests that binding ligands may realize their pivotal roles by regulating the oligomeric status of CXCR4 rather than by simply inducing conformational changes.
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Affiliation(s)
- Jun Lao
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China) , Qingdao 266580, P. R. China
| | - Hua He
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China) , Qingdao 266580, P. R. China
| | - Xiaojuan Wang
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China) , Qingdao 266580, P. R. China
| | - Zhencai Wang
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China) , Qingdao 266580, P. R. China
| | - Yanzhuo Song
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China) , Qingdao 266580, P. R. China
| | - Bin Yang
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China) , Qingdao 266580, P. R. China
| | - Naseer Ullahkhan
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China) , Qingdao 266580, P. R. China
| | - Baosheng Ge
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China) , Qingdao 266580, P. R. China
| | - Fang Huang
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China) , Qingdao 266580, P. R. China
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15
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Wauman J, Zabeau L, Tavernier J. The Leptin Receptor Complex: Heavier Than Expected? Front Endocrinol (Lausanne) 2017; 8:30. [PMID: 28270795 PMCID: PMC5318964 DOI: 10.3389/fendo.2017.00030] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 02/01/2017] [Indexed: 12/31/2022] Open
Abstract
Under normal physiological conditions, leptin and the leptin receptor (ObR) regulate the body weight by balancing food intake and energy expenditure. However, this adipocyte-derived hormone also directs peripheral processes, including immunity, reproduction, and bone metabolism. Leptin, therefore, can act as a metabolic switch connecting the body's nutritional status to high energy consuming processes. We provide an extensive overview of current structural insights on the leptin-ObR interface and ObR activation, coupling to signaling pathways and their negative regulation, and leptin functioning under normal and pathophysiological conditions (obesity, autoimmunity, cancer, … ). We also discuss possible cross-talk with other receptor systems on the receptor (extracellular) and signaling cascade (intracellular) levels.
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Affiliation(s)
- Joris Wauman
- Cytokine Receptor Laboratory, Faculty of Medicine and Health Sciences, Department of Biochemistry, Ghent University, Ghent, Belgium
- VIB Medical Biotechnology Center, VIB, Ghent, Belgium
| | - Lennart Zabeau
- Cytokine Receptor Laboratory, Faculty of Medicine and Health Sciences, Department of Biochemistry, Ghent University, Ghent, Belgium
- VIB Medical Biotechnology Center, VIB, Ghent, Belgium
| | - Jan Tavernier
- Cytokine Receptor Laboratory, Faculty of Medicine and Health Sciences, Department of Biochemistry, Ghent University, Ghent, Belgium
- VIB Medical Biotechnology Center, VIB, Ghent, Belgium
- *Correspondence: Jan Tavernier,
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16
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Maruyama IN. Activation of transmembrane cell-surface receptors via a common mechanism? The "rotation model". Bioessays 2015; 37:959-67. [PMID: 26241732 PMCID: PMC5054922 DOI: 10.1002/bies.201500041] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
It has long been thought that transmembrane cell-surface receptors, such as receptor tyrosine kinases and cytokine receptors, among others, are activated by ligand binding through ligand-induced dimerization of the receptors. However, there is growing evidence that prior to ligand binding, various transmembrane receptors have a preformed, yet inactive, dimeric structure on the cell surface. Various studies also demonstrate that during transmembrane signaling, ligand binding to the extracellular domain of receptor dimers induces a rotation of transmembrane domains, followed by rearrangement and/or activation of intracellular domains. The paper here describes transmembrane cell-surface receptors that are known or proposed to exist in dimeric form prior to ligand binding, and discusses how these preformed dimers are activated by ligand binding.
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Affiliation(s)
- Ichiro N Maruyama
- Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
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17
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Leptin: From structural insights to the design of antagonists. Life Sci 2015; 140:49-56. [PMID: 25998027 DOI: 10.1016/j.lfs.2015.04.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/28/2015] [Accepted: 04/29/2015] [Indexed: 12/20/2022]
Abstract
After its discovery in 1994, it soon became clear that leptin acts as an adipocyte-derived hormone with a central role in the control of body weight and energy homeostasis. However, a growing body of evidence has revealed that leptin is a pleiotropic cytokine with activities on many peripheral cell types. Inappropriate leptin signaling can promote autoimmunity, certain cardiovascular diseases, elevated blood pressure and cancer, which makes leptin and the leptin receptor interesting targets for antagonism. Profound insights in the leptin receptor (LR) activation mechanisms are a prerequisite for the rational design of these antagonists. In this review, we focus on the molecular mechanisms underlying leptin receptor activation and signaling. We also discuss the current strategies to interfere with leptin signaling and their therapeutic potential.
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18
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Sun Y, Periasamy A. Localizing protein-protein interactions in living cells using fluorescence lifetime imaging microscopy. Methods Mol Biol 2015; 1251:83-107. [PMID: 25391796 DOI: 10.1007/978-1-4939-2080-8_6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In the past decade, advances in fluorescence lifetime imaging have extensively applied in the life sciences, from fundamental biological investigations to advanced clinical diagnosis. Fluorescence lifetime imaging microscopy (FLIM) is now routinely used in the biological sciences to monitor dynamic signaling events inside living cells, e.g., Protein-Protein interactions. In this chapter, we describe the calibration of both time-correlated single-photon counting (TCSPC) and frequency domain (FD) FLIM systems and the acquisition and analysis of FLIM-FRET data for investigating Protein-Protein interactions in living cells.
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Affiliation(s)
- Yuansheng Sun
- W.M. Keck Center for Cellular Imaging, Biology, University of Virginia, B005 Physical and Life Sciences Building, White Head Road, Charlottesville, VA, 22904, USA
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19
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Peelman F, Zabeau L, Moharana K, Savvides SN, Tavernier J. 20 years of leptin: insights into signaling assemblies of the leptin receptor. J Endocrinol 2014; 223:T9-23. [PMID: 25063754 DOI: 10.1530/joe-14-0264] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Leptin plays a central role in the control of body weight and energy homeostasis, but is a pleiotropic cytokine with activities on many peripheral cell types. In this review, we discuss the interaction of leptin with its receptor, and focus on the structural and mechanistic aspects of the extracellular aspects of leptin receptor (LR) activation. We provide an extensive overview of all structural information that has been obtained for leptin and its receptor via X-ray crystallography, electron microscopy, small-angle X-ray scattering, homology modeling, and mutagenesis studies. The available knowledge is integrated into putative models toward a recapitulation of the LR activation mechanism.
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Affiliation(s)
- Frank Peelman
- Department of Medical Protein ResearchFaculty of Medicine and Health Sciences, Flanders Institute for Biotechnology (VIB), Ghent University, A. Baertsoenkaai 3, 9000 Ghent, BelgiumUnit for Structural BiologyLaboratory for Protein Biochemistry and Biomolecular Engineering (L-ProBE), Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Lennart Zabeau
- Department of Medical Protein ResearchFaculty of Medicine and Health Sciences, Flanders Institute for Biotechnology (VIB), Ghent University, A. Baertsoenkaai 3, 9000 Ghent, BelgiumUnit for Structural BiologyLaboratory for Protein Biochemistry and Biomolecular Engineering (L-ProBE), Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Kedar Moharana
- Department of Medical Protein ResearchFaculty of Medicine and Health Sciences, Flanders Institute for Biotechnology (VIB), Ghent University, A. Baertsoenkaai 3, 9000 Ghent, BelgiumUnit for Structural BiologyLaboratory for Protein Biochemistry and Biomolecular Engineering (L-ProBE), Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Savvas N Savvides
- Department of Medical Protein ResearchFaculty of Medicine and Health Sciences, Flanders Institute for Biotechnology (VIB), Ghent University, A. Baertsoenkaai 3, 9000 Ghent, BelgiumUnit for Structural BiologyLaboratory for Protein Biochemistry and Biomolecular Engineering (L-ProBE), Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Jan Tavernier
- Department of Medical Protein ResearchFaculty of Medicine and Health Sciences, Flanders Institute for Biotechnology (VIB), Ghent University, A. Baertsoenkaai 3, 9000 Ghent, BelgiumUnit for Structural BiologyLaboratory for Protein Biochemistry and Biomolecular Engineering (L-ProBE), Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
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20
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Moharana K, Zabeau L, Peelman F, Ringler P, Stahlberg H, Tavernier J, Savvides S. Structural and Mechanistic Paradigm of Leptin Receptor Activation Revealed by Complexes with Wild-Type and Antagonist Leptins. Structure 2014; 22:866-77. [DOI: 10.1016/j.str.2014.04.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 04/17/2014] [Accepted: 04/24/2014] [Indexed: 12/18/2022]
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21
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Klepárník K, Foret F. Recent advances in the development of single cell analysis--a review. Anal Chim Acta 2013; 800:12-21. [PMID: 24120162 DOI: 10.1016/j.aca.2013.09.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 08/23/2013] [Accepted: 09/05/2013] [Indexed: 01/12/2023]
Abstract
Development of techniques for the analysis of the content of individual cells represents an important direction in modern bioanalytical chemistry. While the analysis of chromosomes, organelles, or location of selected proteins has been traditionally the domain of microscopic techniques, the advances in miniaturized analytical systems bring new possibilities for separations and detections of molecules inside the individual cells including smaller molecules such as hormones or metabolites. It should be stressed that the field of single cell analysis is very broad, covering advanced optical, electrochemical and mass spectrometry instrumentation, sensor technology and separation techniques. The number of papers published on single cell analysis has reached several hundred in recent years. Thus a complete literature coverage is beyond the limits of a journal article. The following text provides a critical overview of some of the latest developments with the main focus on mass spectrometry, microseparation methods, electrophoresis in capillaries and microfluidic devices and respective detection techniques for performing single cell analyses.
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Affiliation(s)
- Karel Klepárník
- Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic, Brno, Czech Republic.
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22
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Shehzad A, Khan S, Sup Lee Y. Curcumin molecular targets in obesity and obesity-related cancers. Future Oncol 2012; 8:179-90. [DOI: 10.2217/fon.11.145] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Obesity is characterized as an increased BMI, which is associated with the increased risk of several common cancers, including colorectal, breast, endometrial, renal, esophageal, gallbladder, melanoma, multiple myeloma, leukemia, lymphoma and prostate cancer. The increased risk of obesity-related cancers could be mediated by insulin resistance, adipokines, obesity-related inflammatory cytokines, sex hormones, transcription factors and oxidative stress, which disrupt the balance between cell proliferation and apoptosis. The yellowish compound, curcumin (diferuloylmethane), is known to possess multifaceted pharmacological effects. The molecular mechanisms linking obesity to cancer risk, and how curcumin mediates anticancer and obesity activities, have not yet been publicized. Curcumin modulates multiple molecular targets and reverses insulin resistance as well as other symptoms that are associated with obesity-related cancers. In this study, we show that ample evidence exists to support recommendations that curcumin mediates multiple molecular pathways, and is considered to be of therapeutic value in the treatment and prevention of obesity-related cancers.
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Affiliation(s)
- Adeeb Shehzad
- School of life Sciences, College of Natural Sciences, Kyungpook National University, 1370 Sangeok-dong, Buk-ku, Daegu 702–701, Korea
| | - Salman Khan
- Department of Pharmacy, Seoul National University, Gwanak-gu, Seoul 151–015, Korea
| | - Young Sup Lee
- School of life Sciences, College of Natural Sciences, Kyungpook National University, 1370 Sangeok-dong, Buk-ku, Daegu 702–701, Korea
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23
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Sun Y, Day RN, Periasamy A. Investigating protein-protein interactions in living cells using fluorescence lifetime imaging microscopy. Nat Protoc 2011; 6:1324-40. [PMID: 21886099 PMCID: PMC3169422 DOI: 10.1038/nprot.2011.364] [Citation(s) in RCA: 175] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Fluorescence lifetime imaging microscopy (FLIM) is now routinely used for dynamic measurements of signaling events inside living cells, including detection of protein-protein interactions. An understanding of the basic physics of fluorescence lifetime measurements is required to use this technique. In this protocol, we describe both the time-correlated single photon counting and the frequency-domain methods for FLIM data acquisition and analysis. We describe calibration of both FLIM systems, and demonstrate how they are used to measure the quenched donor fluorescence lifetime that results from Förster resonance energy transfer (FRET). We then show how the FLIM-FRET methods are used to detect the dimerization of the transcription factor CCAAT/enhancer binding protein-α in live mouse pituitary cell nuclei. Notably, the factors required for accurate determination and reproducibility of lifetime measurements are described. With either method, the entire protocol including specimen preparation, imaging and data analysis takes ∼2 d.
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Affiliation(s)
- Yuansheng Sun
- W.M. Keck Center for Cellular Imaging, Department of Biology, University of Virginia, Charlottesville, Virginia, USA
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24
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Sun Y, Wallrabe H, Seo SA, Periasamy A. FRET microscopy in 2010: the legacy of Theodor Förster on the 100th anniversary of his birth. Chemphyschem 2011; 12:462-74. [PMID: 21344587 PMCID: PMC3422661 DOI: 10.1002/cphc.201000664] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Indexed: 11/09/2022]
Abstract
Theodor Förster would have been 100 years old this year, and he would have been astounded to see the impact of his scientific achievement, which is still evolving. Combining his quantitative approach of (Förster) resonance energy transfer (FRET) with state-of-the-art digital imaging techniques allows scientists to breach the resolution limits of light (ca. 200 nm) in light microscopy. The ability to deduce molecular or particle distances within a range of 1-10 nm in real time and to prove or disprove interactions between two or more components is of vital interest to researchers in many branches of science. While Förster's groundbreaking theory was published in the 1940s, the availability of suitable fluorophores, instruments, and analytical tools spawned numerous experiments in the last 20 years, as demonstrated by the exponential increase in publications. These cover basic investigation of cellular processes and the ability to investigate them when they go awry in pathological states, the dynamics involved in genetics, and following events in environmental sciences and methods in drug screening. This review covers the essentials of Theodor Förster's theory, describes the elements for successful implementation of FRET microscopy, the challenges and how to overcome them, and a leading-edge example of how Förster's scientific impact is still evolving in many directions. While this review cannot possibly do justice to the burgeoning field of FRET microscopy, a few interesting applications such as threecolor FRET, which greatly expands the opportunities for investigating interactions of cellular components compared with the traditional two-color method, are described, and an extensive list of references is provided for the interested reader to access.
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Affiliation(s)
- Yuansheng Sun
- W.M. Keck Center for Cellular Imaging, Departments of Biology and Biomedical Engineering, University of Virginia, Charlottesville, VA 22904
| | - Horst Wallrabe
- W.M. Keck Center for Cellular Imaging, Departments of Biology and Biomedical Engineering, University of Virginia, Charlottesville, VA 22904
| | - Soo-Ah Seo
- W.M. Keck Center for Cellular Imaging, Departments of Biology and Biomedical Engineering, University of Virginia, Charlottesville, VA 22904
| | - Ammasi Periasamy
- W.M. Keck Center for Cellular Imaging, Departments of Biology and Biomedical Engineering, University of Virginia, Charlottesville, VA 22904
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Kapur S, Amoui M, Kesavan C, Wang X, Mohan S, Baylink DJ, Lau KHW. Leptin receptor (Lepr) is a negative modulator of bone mechanosensitivity and genetic variations in Lepr may contribute to the differential osteogenic response to mechanical stimulation in the C57BL/6J and C3H/HeJ pair of mouse strains. J Biol Chem 2010; 285:37607-18. [PMID: 20851886 PMCID: PMC2988366 DOI: 10.1074/jbc.m110.169714] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This study investigated the role of leptin receptor (Lepr) signaling in determining the bone mechanosensitivity and also evaluated whether differences in the Lepr signaling may contribute to the differential osteogenic response of the C57BL/6J (B6) and C3H/HeJ (C3H) pair of mouse strains to mechanical stimuli. This study shows that a loading strain of ∼2,500 με, which was insufficient to produce a bone formation response in B6 mice, significantly increased bone formation parameters in leptin-deficient ob(-)/ob(-) mice and that a loading strain of ∼3,000 με also yielded greater osteogenic responses in Lepr-deficient db(-)/db(-) mice than in wild-type littermates. In vitro, a 30-min steady shear stress increased [(3)H]thymidine incorporation and Erk1/2 phosphorylation in ob(-)/ob(-) osteoblasts and db(-)/db(-) osteoblasts much greater than those in corresponding wild-type osteoblasts. The siRNA-mediated suppression of Lepr expression in B6 osteoblasts enhanced (but in osteoblasts of C3H (the mouse strain with poor bone mechanosensitivity) restored) their anabolic responses to shear stress. The Lepr signaling (leptin-induced Jak2/Stat3 phosphorylation) in C3H osteoblasts was higher than that in B6 osteoblasts. One of the three single nucleotide polymorphisms in the C3H Lepr coding region yielded an I359V substitution near the leptin binding region, suggesting that genetic variation of Lepr may contribute to a dysfunctional Lepr signaling in C3H osteoblasts. In conclusion, Lepr signaling is a negative modulator of bone mechanosensitivity. Genetic variations in Lepr, which result in a dysfunctional Lepr signaling in C3H mice, may contribute to the poor osteogenic response to loading in C3H mice.
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Affiliation(s)
- Sonia Kapur
- Musculoskeletal Disease Center, Jerry L Pettis Memorial Veterans Affairs Medical Center, Loma Linda, California 92357, USA
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26
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Oligomeric sensor kinase DcuS in the membrane of Escherichia coli and in proteoliposomes: chemical cross-linking and FRET spectroscopy. J Bacteriol 2010; 192:3474-83. [PMID: 20453099 DOI: 10.1128/jb.00082-10] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
DcuS is the membrane-integral sensor histidine kinase of the DcuSR two-component system in Escherichia coli that responds to extracellular C(4)-dicarboxylates. The oligomeric state of full-length DcuS was investigated in vitro and in living cells by chemical cross-linking and by fluorescence resonance energy transfer (FRET) spectroscopy. The FRET results were quantified by an improved method using background-free spectra of living cells for determining FRET efficiency (E) and donor fraction {f(D) = (donor)/[(donor) + (acceptor)]}. Functional fusions of cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) variants of green fluorescent protein to DcuS were used for in vivo FRET measurements. Based on noninteracting membrane proteins and perfectly interacting proteins (a CFP-YFP fusion), the results of FRET of cells coexpressing DcuS-CFP and DcuS-YFP were quantitatively evaluated. In living cells and after reconstitution of purified recombinant DcuS in proteoliposomes, DcuS was found as a dimer or higher oligomer, independent of the presence of an effector. Chemical cross-linking with disuccinimidyl suberate showed tetrameric, in addition to dimeric, DcuS in proteoliposomes and in membranes of bacteria, whereas purified DcuS in nondenaturing detergent was mainly monomeric. The presence and amount of tetrameric DcuS in vivo and in proteoliposomes was not dependent on the concentration of DcuS. Only membrane-embedded DcuS (present in the oligomeric state) is active in (auto)phosphorylation. Overall, the FRET and cross-linking data demonstrate the presence in living cells, in bacterial membranes, and in proteoliposomes of full-length DcuS protein in an oligomeric state, including a tetramer.
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27
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Bacart J, Leloire A, Levoye A, Froguel P, Jockers R, Couturier C. Evidence for leptin receptor isoforms heteromerization at the cell surface. FEBS Lett 2010; 584:2213-7. [DOI: 10.1016/j.febslet.2010.03.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 03/10/2010] [Accepted: 03/18/2010] [Indexed: 11/16/2022]
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28
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Bernoux M, Timmers T, Jauneau A, Brière C, de Wit PJGM, Marco Y, Deslandes L. RD19, an Arabidopsis cysteine protease required for RRS1-R-mediated resistance, is relocalized to the nucleus by the Ralstonia solanacearum PopP2 effector. THE PLANT CELL 2008; 20:2252-64. [PMID: 18708476 PMCID: PMC2553607 DOI: 10.1105/tpc.108.058685] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Revised: 07/18/2008] [Accepted: 07/31/2008] [Indexed: 05/18/2023]
Abstract
Bacterial wilt, a disease impacting cultivated crops worldwide, is caused by the pathogenic bacterium Ralstonia solanacearum. PopP2 (for Pseudomonas outer protein P2) is an R. solanacearum type III effector that belongs to the YopJ/AvrRxv protein family and interacts with the Arabidopsis thaliana RESISTANT TO RALSTONIA SOLANACEARUM 1-R (RRS1-R) resistance protein. RRS1-R contains the Toll/Interleukin1 receptor-nucleotide binding site-Leu-rich repeat domains found in several cytoplasmic R proteins and a C-terminal WRKY DNA binding domain. In this study, we identified the Arabidopsis Cys protease RESPONSIVE TO DEHYDRATION19 (RD19) as being a PopP2-interacting protein whose expression is induced during infection by R. solanacearum. An Arabidopsis rd19 mutant in an RRS1-R genetic background is compromised in resistance to the bacterium, indicating that RD19 is required for RRS1-R-mediated resistance. RD19 normally localizes in mobile vacuole-associated compartments and, upon coexpression with PopP2, is specifically relocalized to the plant nucleus, where the two proteins physically interact. No direct physical interaction between RRS1-R and RD19 in the presence of PopP2 was detected in the nucleus as determined by Förster resonance energy transfer. We propose that RD19 associates with PopP2 to form a nuclear complex that is required for activation of the RRS1-R-mediated resistance response.
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Affiliation(s)
- Maud Bernoux
- Laboratoire des Interactions Plantes Microorganismes, Unité Mixte de Recherche, Centre National de la Recherche Scientifique-Institut National de la Recherche Agronomique 2594/441, F-31320 Castanet-Tolosan, France
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29
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Liu P, Ahmed S, Wohland T. The F-techniques: advances in receptor protein studies. Trends Endocrinol Metab 2008; 19:181-90. [PMID: 18387308 DOI: 10.1016/j.tem.2008.02.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 02/13/2008] [Accepted: 02/22/2008] [Indexed: 11/20/2022]
Abstract
Recent developments in advanced microscopy techniques, the so-called F-techniques, including Förster resonance energy transfer, fluorescence correlation spectroscopy and fluorescence lifetime imaging, have led to a wide range of novel applications in biology. The F-techniques provide quantitative information on biomolecules and their interactions and give high spatial and temporal resolution. In particular, their application to receptor protein studies has led to new insights into receptor localization, oligomerization, activation and function in vivo. This review focuses on the application of the F-techniques to the study of receptor molecules and mechanisms in the last three years and provides information on new modalities that will further improve their applicability and widen the range of biological questions that can be addressed.
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Affiliation(s)
- Ping Liu
- Department of Chemistry, National University of Singapore, Singapore
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30
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Rieckmann T, Kotevic I, Trueb B. The cell surface receptor FGFRL1 forms constitutive dimers that promote cell adhesion. Exp Cell Res 2008; 314:1071-81. [DOI: 10.1016/j.yexcr.2007.10.029] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Revised: 10/29/2007] [Accepted: 10/29/2007] [Indexed: 12/11/2022]
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31
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Yacobovitz M, Solomon G, Gusakovsky EE, Levavi-Sivan B, Gertler A. Purification and characterization of recombinant pufferfish (Takifugu rubripes) leptin. Gen Comp Endocrinol 2008; 156:83-90. [PMID: 18191858 DOI: 10.1016/j.ygcen.2007.11.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2007] [Revised: 11/11/2007] [Accepted: 11/23/2007] [Indexed: 10/22/2022]
Abstract
Synthetic cDNA encoding pufferfish (Takifugu rubripes) leptin (pfLEP) was prepared according to the published sequence. The pfLEP, transformed into Escherichia coli and expressed upon induction with nalidixic acid, was found almost entirely in the insoluble inclusion bodies (IBs). The proteins were solubilized, refolded and purified to homogeneity by anion-exchange chromatography and gel-filtration. The respective yield of dimers and monomers was 50-100mg from 5L of fermentation culture. Circular dichroism analyses revealed similarity of the purified pfLEP secondary structure to that of mammalian leptins. The purified monomers and dimers showed a single band of approximately 15 kDa following SDS-PAGE in the presence of reducing agent, whereas the dimer showed one band of approximately 30 kDa in the absence of reducing agent, indicating its formation by S-S bonds. The purified product also showed a single peak following gel-filtration under nondenaturating conditions and reverse-phase chromatography. Monomeric and dimeric pfLEPs were stable for at least 6 months in sterile solution frozen at -20 degrees C or as lyophilized powder. Both pfLEPs were biologically active in promoting proliferation of BAF/3 cells stably transfected with the long form of human leptin (hLEP) receptor, but their activity was four to five orders of magnitude lower than that of hLEP. The specificity of this activity was further evidenced by its complete inhibition by hLEP antagonist. In contrast to mammalian leptins, neither form of pfLEP bound to or formed 1:1 complex with chicken leptin-binding domain, likely due to low affinity. No specific binding of either ovine or pufferfish leptins to tilapia liver membranes was detected. This work is the first report on the purification of leptin from any fish species.
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Affiliation(s)
- M Yacobovitz
- Institute of Biochemistry, Food Science and Nutrition, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel
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Wu X, Currall B, Yamashita T, Parker LL, Hallworth R, Zuo J. Prestin-prestin and prestin-GLUT5 interactions in HEK293T cells. Dev Neurobiol 2007; 67:483-97. [PMID: 17443803 DOI: 10.1002/dneu.20357] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The remarkable hearing sensitivity and frequency selectivity in mammals is attributed to cochlear amplifier in the outer hair cells (OHCs). Prestin, a membrane protein in the lateral wall of OHC plasma membrane, is required for OHC electromotility and cochlear amplifier. In addition, GLUT5, a fructose transporter, is reported to be abundant in the plasma membrane of the OHC lateral wall and has been originally proposed as the OHC motor protein. Here we provide evidence of interactions between prestin/prestin and prestin/GLUT5 in transiently transfected HEK293T cells. We used a combination of techniques: (1) membrane colocalization by confocal microscopy, (2) fluorescence resonance energy transfer (FRET) by fluorescence activated cell sorting (FACS), (3) FRET by acceptor photobleaching, (4) FRET by fluorescence lifetime imaging (FRET-FLIM), and (5) coimmunoprecipitation. Our results suggest that homomeric and heteromeric prestin interactions occur in native OHCs to facilitate its electromotile function and that GLUT5 interacts with prestin for its elusive function.
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Affiliation(s)
- Xudong Wu
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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Biener-Ramanujan E, Ramanujan VK, Herman B, Gertler A. Spatio-temporal kinetics of growth hormone receptor signaling in single cells using FRET microscopy. Growth Horm IGF Res 2006; 16:247-257. [PMID: 16950496 DOI: 10.1016/j.ghir.2006.06.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Revised: 06/13/2006] [Accepted: 06/14/2006] [Indexed: 10/24/2022]
Abstract
The growth hormone (GH) receptor (R)-mediated JAK2 (Janus kinase-2)-STAT5 (signaling transducer and activator of transcription-5) pathway involves a cascade of protein-protein interactions and tyrosine phosphorylations that occur in a spatially and temporally sensitive manner in cells. To study GHR dimerization or GH-induced conformational change of predimerized GHRs and STAT5 activation kinetics in intact cells, fluorescence resonance energy transfer (FRET) and live-cell imaging methods were employed. FRET measurements at the membrane of HEK-293T cells co-expressing GHRs tagged at the C-terminus with cyan (C) and yellow (Y) fluorescent proteins (FPs) revealed transient GHR dimerization lasting 2-3 min, with a maximum at 3 min after GH stimulation, which was sufficient to induce STAT5 activation. The transient nature of the dimerization or GH-induced conformational change of predimerized GHRs kinetics was not a result of GHR internalization, as neither potassium- nor cholesterol-depletion treatments prolonged the FRET signal. YFP-tagged STAT5 recruitment to the membrane, binding to GHR-CFP, and phosphorylation, occurred within minutes of GH stimulation. Activated STAT5a-YFP did not show nuclear accumulation, despite nuclear pSTAT5 increase, suggesting high turnover of STAT5 nuclear shuttling. Although GHR dimerization and STAT5 activation have been reported previously, this is the first spatially resolved demonstration of GHR-signaling kinetics in intact cells.
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Affiliation(s)
- Eva Biener-Ramanujan
- The Institute of Biochemistry, Food Science, and Nutrition, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot, Israel
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Zhang Y, Vogel WK, McCullar JS, Greenwood JA, Filtz TM. Phospholipase C-β3 and -β1 Form Homodimers, but Not Heterodimers, through Catalytic and Carboxyl-Terminal Domains. Mol Pharmacol 2006; 70:860-8. [PMID: 16763092 DOI: 10.1124/mol.105.021923] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Phospholipase C-beta (PLC-beta) isoenzymes are key effectors in G protein-coupled signaling pathways. Prior research suggests that some isoforms of PLC-beta may exist and function as dimers. Using coimmunoprecipitation assays of differentially tagged PLC-beta constructs and size-exclusion chromatography of native PLC-beta, we observed homodimerization of PLC-beta3 and PLC-beta1 isoenzymes but failed to detect heterodimerization of these isoenzymes. Size-exclusion chromatography data suggest that PLC-beta3 and PLC-beta1 form higher affinity homodimers than PLC-beta2. Evidence supportive of limited PLC-beta monomer-homodimer equilibrium appears at < or =100 nM. Further assessment of homodimerization status by coimmunoprecipitation assays with differentially tagged PLC-beta3 fragments demonstrated that at least two subdomains of PLC-beta3 are involved in dimer formation, one in the catalytic X and Y domains and the other in the G protein-regulated carboxyl-terminal domain. In addition, we provide evidence consistent with the existence of PLC-beta homodimers in a whole-cell context, using fluorescent protein-tagged constructs and microscopic fluorescence resonance energy transfer assays.
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Affiliation(s)
- Yong Zhang
- Molecular and Cellular Biology Program, 203 Pharmacy Building, Oregon State University, Corvallis, OR 97331-3507, USA
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Peelman F, Couturier C, Dam J, Zabeau L, Tavernier J, Jockers R. Techniques: new pharmacological perspectives for the leptin receptor. Trends Pharmacol Sci 2006; 27:218-25. [PMID: 16537093 DOI: 10.1016/j.tips.2006.02.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Revised: 01/04/2006] [Accepted: 02/23/2006] [Indexed: 11/28/2022]
Abstract
The function of leptin, initially confined to its role in energy homeostasis and obesity, has now expanded to the regulation of reproduction, glucose homeostasis, bone formation, wound healing and the immune system. Both stimulation and inhibition of the molecular target of leptin, the leptin receptor (LR), might find applications in disease treatment. Recent advances in the understanding of LR activation mechanisms have led to the design of LR antagonists. Several assays have been developed for the screening and evaluation of LR ligands. Both the extracellular and the intracellular domains of the LR are potential drug targets. The bioluminescence resonance energy transfer technique can be used to screen for compounds that target the extracellular part of the LR, and we propose that the novel reverse mammalian protein-protein interaction trap technique can be used to screen compounds that affect intracellular aspects of LR signalling. These assays can be easily adapted to other pharmacologically relevant receptors.
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Affiliation(s)
- Frank Peelman
- Flanders Interuniversity Institute for Biotechnology, VIB09, Department of Medical Protein Research, Faculty of Medicine and Health Sciences, Ghent University, Albert Baertsonenkaai 3, B-9000 Ghent, Belgium
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Breusegem SY, Levi M, Barry NP. Fluorescence Correlation Spectroscopy and Fluorescence Lifetime Imaging Microscopy. ACTA ACUST UNITED AC 2006; 103:e41-9. [PMID: 16543763 DOI: 10.1159/000090615] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
With few and commercially available add-ons, both confocal and full-field fluorescence microscopes can be adapted to provide more information on the biological sample of interest. In this review we discuss the possibilities offered by two additional functionalities to fluorescence microscopes, fluorescence correlation spectroscopy (FCS) and fluorescence lifetime imaging mi croscopy (FLIM). FCS measurements at a single point in a sample allow kinetic and diffusion properties of fluorescently labeled molecules to be determined, as well as their concentration and aggregation state. Data from multiple points of the sample can be acquired using scanning-FCS, image correlation spectroscopy, and raster image correlation spectroscopy. These techniques cover phenomena with characteristic durations from sub-microsecond to second time scales. The power of FLIM lies in the fact that the measured fluorescent lifetime of a fluorophore is sensitive to the molecular environment of that fluorophore. FLIM is a robust means to quantify Forster resonance energy transfer and thus determine protein-protein interactions or protein conformational changes. In addition, FLIM is very valuable for functional imaging of ion concentrations in cells and tissues as it can be applied in heterogeneously labeled samples. In summary, FCS and FLIM allow information to be gathered beyond localization, including diffusional mobility, protein clustering and interactions, and molecular environment.
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Affiliation(s)
- Sophia Y Breusegem
- Department of Medicine, Division of Renal Diseases and Hypertension, University of Colorado Health Sciences Center, Denver, Colo 80262, USA
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Niv-Spector L, Gonen-Berger D, Gourdou I, Biener E, Gussakovsky E, Benomar Y, Ramanujan K, Taouis M, Herman B, Callebaut I, Djiane J, Gertler A. Identification of the hydrophobic strand in the A-B loop of leptin as major binding site III: implications for large-scale preparation of potent recombinant human and ovine leptin antagonists. Biochem J 2005; 391:221-30. [PMID: 15952938 PMCID: PMC1276919 DOI: 10.1042/bj20050457] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Revised: 05/16/2005] [Accepted: 06/14/2005] [Indexed: 01/29/2023]
Abstract
Interaction of leptin with its receptors resembles that of interleukin-6 and granulocyte colony-stimulating factor, which interact with their receptors through binding sites I-III. Site III plays a pivotal role in receptors' dimerization or tetramerization and subsequent activation. Leptin's site III also mediates the formation of an active multimeric complex through its interaction with the IGD (immunoglobulin-like domain) of LEPRs (leptin receptors). Using a sensitive hydrophobic cluster analysis of leptin's and LEPR's sequences, we identified hydrophobic stretches in leptin's A-B loop (amino acids 39-42) and in the N-terminal end of LEPR's IGD (amino acids 325-328) that are predicted to participate in site III and to interact with each other in a beta-sheet-like configuration. To verify this hypothesis, we prepared and purified to homogeneity (as verified by SDS/PAGE, gel filtration and reverse-phase chromatography) several alanine muteins of amino acids 39-42 in human and ovine leptins. CD analyses revealed that those mutations hardly affect the secondary structure. All muteins acted as true antagonists, i.e. they bound LEPR with an affinity similar to the wild-type hormone, had no agonistic activity and specifically inhibited leptin action in several leptin-responsive in vitro bioassays. Alanine mutagenesis of LEPR's IGD (amino acids 325-328) drastically reduced its biological but not binding activity, indicating the importance of this region for interaction with leptin's site III. FRET (fluorescence resonance energy transfer) microscopy experiments have documented that the transient FRET signalling occurring upon exposure to leptin results not from binding of the ligand, but from ligand-induced oligomerization of LEPRs mediated by leptin's site III.
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Key Words
- a–b loop of leptin
- antagonists
- fluorescence resonance energy transfer (fret)
- hydrophobic strand
- immunoglobulin-like domain (igd)
- site-directed mutagenesis
- apb, acceptor photobleaching
- cfp, cyan fluorescent protein
- ch, chicken
- cho, chinese-hamster ovary
- crh, cytokine receptor homology domain
- erk, extracellular-signal-regulated kinase
- g-csf, granulocyte colony-stimulating factor
- h, human
- hca, hydrophobic cluster analysis
- hek-293t cells, human embryonic kidney 293t cells
- ibs, inclusion bodies
- il-6, interleukin-6
- igd, immunoglobulin-like domain
- lbd, leptin-binding domain
- lepr, leptin receptor
- m, mouse
- mapk, mitogen-activated protein kinase
- mtt, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2h-tetrazolium bromide
- spr, surface plasmon resonance, stat3, signal transducer and activator of transcription 3
- tfa, trifluoroacetic acid
- v, viral
- wt, wild-type
- yfp, yellow fluorescent protein
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Affiliation(s)
- Leonora Niv-Spector
- *Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University, Rehovot 76100, Israel
| | - Dana Gonen-Berger
- *Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University, Rehovot 76100, Israel
| | - Isabelle Gourdou
- †Institut National de la Recherche Agronomique, Neuroendocrinologie Moleculaire de la Prise Alimentaire, 78352 Jouy-en-Josas Cedex, France
| | - Eva Biener
- *Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University, Rehovot 76100, Israel
| | - Eugene E. Gussakovsky
- ‡Department of Life Sciences, Bar Ilan University, Ramat Gan 52900, Israel
- §Institute of Horticulture, The Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel
| | - Yackir Benomar
- ∥Laboratoire d'Endocrinologie, University of Paris XI, Orsay 91405, France
| | - Krishnan V. Ramanujan
- ¶Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, U.S.A
| | - Mohammed Taouis
- ∥Laboratoire d'Endocrinologie, University of Paris XI, Orsay 91405, France
| | - Brian Herman
- ¶Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, U.S.A
| | - Isabelle Callebaut
- **Institut de Mineralogie et de Physique des Milieux Condenses, CNRS UMR7590, Universities Paris 6 & Paris 7, Paris Cedex 05, France
| | - Jean Djiane
- †Institut National de la Recherche Agronomique, Neuroendocrinologie Moleculaire de la Prise Alimentaire, 78352 Jouy-en-Josas Cedex, France
| | - Arieh Gertler
- *Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University, Rehovot 76100, Israel
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