1
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Azzi E, Fayyad-Kazan M, Kabrita CS. Characterization of circulating leptin-receptor levels following acute sleep restriction: A pilot study on healthy adult females. Physiol Behav 2024; 279:114543. [PMID: 38565330 DOI: 10.1016/j.physbeh.2024.114543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 03/19/2024] [Accepted: 03/30/2024] [Indexed: 04/04/2024]
Abstract
BACKGROUND Insufficient sleep adversely affects energy homeostasis by decreasing leptin levels. The underlying physiological mechanisms; however, remain unclear. Circulating leptin is well described to be regulated by its soluble receptor (sOB-R). Intriguingly, the impact of short sleep duration on sOB-R levels has never been characterized. AIM In this study, we investigated, for the first time, the variation of sOB-R levels and its temporal relationship with circulating leptin upon acute sleep restriction. METHODS Five adult females were maintained on an 8-hour sleep schedule (bedtime at 00:00) for 1 week before restricting their sleep to 4.5 h (bedtime at 03:30) on 2 consecutive nights. Balanced meals were scheduled to specific hours and sleep was objectively measured. Four-hour blood samples were regularly collected during waking hours between 08:00 and 00:00. RESULTS Sleep restriction resulted in lower leptin (20.9 ± 1.7 vs 25.7 ± 1.7 ng/ml) and higher sOB-R concentrations (24.4 ± 1.2 vs 19.8 ± 1.6 ng/ml). Neither the discordant temporal relationship nor the pattern of leptin and sOB-R were altered in response to sleep restriction. CONCLUSION Our results suggest that sleep restriction may modulate circulating leptin levels and possibly metabolism via upregulating its soluble receptor. This observation may have valuable therapeutic implications when considering sOB-R as a potential target during the management of metabolic disturbances.
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Affiliation(s)
- Elissar Azzi
- Notre Dame University-Louaize (NDU), Faculty of Natural and Applied Sciences, Department of Sciences, Zouk Mosbeh, Lebanon; Institute for Molecular Medicine Finland FIMM, HiLIFE, University of Helsinki, Helsinki, Finland.
| | - Mohammad Fayyad-Kazan
- The American University of Iraq-Baghdad (AUIB), College of Arts and Sciences, Department of Natural and Applied Sciences, Baghdad, Iraq
| | - Colette S Kabrita
- Notre Dame University-Louaize (NDU), Faculty of Natural and Applied Sciences, Department of Sciences, Zouk Mosbeh, Lebanon; The American University of Iraq-Baghdad (AUIB), College of Arts and Sciences, Department of Natural and Applied Sciences, Baghdad, Iraq.
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2
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Berger C, Klöting N. Leptin Receptor Compound Heterozygosity in Humans and Animal Models. Int J Mol Sci 2021; 22:4475. [PMID: 33922961 PMCID: PMC8123313 DOI: 10.3390/ijms22094475] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/14/2021] [Accepted: 04/20/2021] [Indexed: 01/10/2023] Open
Abstract
Leptin and its receptor are essential for regulating food intake, energy expenditure, glucose homeostasis and fertility. Mutations within leptin or the leptin receptor cause early-onset obesity and hyperphagia, as described in human and animal models. The effect of both heterozygous and homozygous variants is much more investigated than compound heterozygous ones. Recently, we discovered a spontaneous compound heterozygous mutation within the leptin receptor, resulting in a considerably more obese phenotype than described for the homozygous leptin receptor deficient mice. Accordingly, we focus on compound heterozygous mutations of the leptin receptor and their effects on health, as well as possible therapy options in human and animal models in this review.
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Affiliation(s)
- Claudia Berger
- Medical Department III, Endocrinology, Nephrology, Rheumatology, CRC1052, University of Leipzig Medical Center, 04103 Leipzig, Germany;
| | - Nora Klöting
- Medical Department III, Endocrinology, Nephrology, Rheumatology, CRC1052, University of Leipzig Medical Center, 04103 Leipzig, Germany;
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at University of Leipzig, 04103 Leipzig, Germany
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3
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Guo Y, Xu C, Wu X, Zhang W, Sun Y, Shrestha A. Leptin regulates OPG and RANKL expression in Gingival Fibroblasts and Tissues of Chronic Periodontitis Patients. Int J Med Sci 2021; 18:2431-2437. [PMID: 33967621 PMCID: PMC8100636 DOI: 10.7150/ijms.56151] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 04/06/2021] [Indexed: 11/05/2022] Open
Abstract
Objective: Chronic periodontitis is a bone-destructive disease affecting periodontal support structures. Although leptin has a protective effect against periodontitis, the underlying mechanism remains unclear. Therefore, this study aimed to investigate the possible role of leptin by examining its relationship with OPG and RANKL in human gingival tissues obtained from patients with chronic periodontitis. Method: Twenty-two patients with chronic periodontitis were enrolled (10 with moderate periodontitis and 12 with severe periodontitis) in the experimental group, and 12 healthy individuals were enrolled in the control group. Gingival tissue samples were collected, and the protein levels and localization of leptin, OPG, and RANKL were studied using immunohistochemistry (IHC). The staining intensities of leptin, OPG, and RANKL were correlated with the periodontal clinical index. Moreover, real-time quantitative PCR (RT-qPCR) was used to determine OPG and RANKL mRNA levels in gingival fibroblasts stimulated with gradient concentrations of leptin protein in vitro. Result: Leptin, OPG, and RANKL were located in the cytoplasm of gingival epithelial cells and the connective tissue. Leptin was widely and significantly expressed in the control group, whereas it was lightly stained in the severe group. RANKL was lightly stained in the control group, whereas it was widely and significantly expressed in the severe group. The control and the moderate groups had similar OPG levels, which were significantly higher than that in the severe group. Leptin was positively correlated with OPG(r = 0.905, p < 0.01) and negatively correlated with RANKL (r = -0.635, p < 0.01). In vitro low concentrations of leptin led to an increased OPG/RANKL mRNA ratio, whereas the opposite effect was observed at high concentrations. Conclusion: Leptin can regulate OPG and RANKL expression in gingival fibroblasts and may thus play a role in the development of chronic periodontitis by modulating the OPG/RANKL ratio.
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Affiliation(s)
- Yiting Guo
- Central of Stomatology, Xiangya Hospital of Central South University, Changsha, China.,Stomatological Hospital of Xiamen Medical College, Xiamen, China
| | - Chunjiao Xu
- Central of Stomatology, Xiangya Hospital of Central South University, Changsha, China
| | - Xiaoshan Wu
- Central of Stomatology, Xiangya Hospital of Central South University, Changsha, China
| | - Wenrui Zhang
- Central of Stomatology, Xiangya Hospital of Central South University, Changsha, China
| | - Yumei Sun
- Central of Stomatology, Xiangya Hospital of Central South University, Changsha, China
| | - Alisha Shrestha
- Central of Stomatology, Xiangya Hospital of Central South University, Changsha, China
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4
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Olea-Flores M, Juárez-Cruz JC, Zuñiga-Eulogio MD, Acosta E, García-Rodríguez E, Zacapala-Gomez AE, Mendoza-Catalán MA, Ortiz-Ortiz J, Ortuño-Pineda C, Navarro-Tito N. New Actors Driving the Epithelial-Mesenchymal Transition in Cancer: The Role of Leptin. Biomolecules 2020; 10:E1676. [PMID: 33334030 PMCID: PMC7765557 DOI: 10.3390/biom10121676] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/12/2020] [Accepted: 12/13/2020] [Indexed: 12/24/2022] Open
Abstract
Leptin is a hormone secreted mainly by adipocytes; physiologically, it participates in the control of appetite and energy expenditure. However, it has also been linked to tumor progression in different epithelial cancers. In this review, we describe the effect of leptin on epithelial-mesenchymal transition (EMT) markers in different study models, including in vitro, in vivo, and patient studies and in various types of cancer, including breast, prostate, lung, and ovarian cancer. The different studies report that leptin promotes the expression of mesenchymal markers and a decrease in epithelial markers, in addition to promoting EMT-related processes such as cell migration and invasion and poor prognosis in patients with cancer. Finally, we report that leptin has the greatest biological relevance in EMT and tumor progression in breast, lung, prostate, esophageal, and ovarian cancer. This relationship could be due to the key role played by the enriched tumor microenvironment in adipose tissue. Together, these findings demonstrate that leptin is a key biomolecule that drives EMT and metastasis in cancer.
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Affiliation(s)
- Monserrat Olea-Flores
- Laboratorio de Biología Celular del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo 39090, Mexico; (M.O.-F.); (J.C.J.-C.); (M.D.Z.-E.); (E.A.); (E.G.-R.)
| | - Juan C. Juárez-Cruz
- Laboratorio de Biología Celular del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo 39090, Mexico; (M.O.-F.); (J.C.J.-C.); (M.D.Z.-E.); (E.A.); (E.G.-R.)
| | - Miriam D. Zuñiga-Eulogio
- Laboratorio de Biología Celular del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo 39090, Mexico; (M.O.-F.); (J.C.J.-C.); (M.D.Z.-E.); (E.A.); (E.G.-R.)
| | - Erika Acosta
- Laboratorio de Biología Celular del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo 39090, Mexico; (M.O.-F.); (J.C.J.-C.); (M.D.Z.-E.); (E.A.); (E.G.-R.)
| | - Eduardo García-Rodríguez
- Laboratorio de Biología Celular del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo 39090, Mexico; (M.O.-F.); (J.C.J.-C.); (M.D.Z.-E.); (E.A.); (E.G.-R.)
| | - Ana E. Zacapala-Gomez
- Laboratorio de Biomedicina Molecular, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo 39090, Mexico; (A.E.Z.-G.); (M.A.M.-C.); (J.O.-O.)
| | - Miguel A. Mendoza-Catalán
- Laboratorio de Biomedicina Molecular, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo 39090, Mexico; (A.E.Z.-G.); (M.A.M.-C.); (J.O.-O.)
| | - Julio Ortiz-Ortiz
- Laboratorio de Biomedicina Molecular, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo 39090, Mexico; (A.E.Z.-G.); (M.A.M.-C.); (J.O.-O.)
| | - Carlos Ortuño-Pineda
- Laboratorio de Ácidos Nucleicos y Proteinas, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo 39090, Mexico;
| | - Napoleón Navarro-Tito
- Laboratorio de Biología Celular del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo 39090, Mexico; (M.O.-F.); (J.C.J.-C.); (M.D.Z.-E.); (E.A.); (E.G.-R.)
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5
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Han H, Zhou W. Leptin and Its Derivatives: A Potential Target for Autoimmune Diseases. Curr Drug Targets 2020; 20:1563-1571. [PMID: 31362672 DOI: 10.2174/1389450120666190729120557] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/16/2019] [Accepted: 07/17/2019] [Indexed: 11/22/2022]
Abstract
Leptin is an adipocyte-derived hormone product of the obese (ob) gene. Leptin plays an important regulatory role as an immunomodulatory factor in the maintenance and homeostasis of immune functions. Indeed, the role of leptin as an immunomodulator in inflammatory and immune responses has attracted increasing attention in recent years. Leptin mostly affects responses through the immunomodulation of monocytes, dendritic cells, neutrophils, NK cells, and dendritic cells in addition to modulating T and B cell development and functions. Leptin is also an important inflammatory regulator, wherein higher expression influences the secretion rates of IL-6, C-reactive proteins, and TNF-α. Moreover, leptin is highly involved in processes related to human metabolism, inflammatory reactions, cellular development, and diseases, including hematopoiesis. Owing to its diverse immunerelated functions, leptin has been explored as a potential target for therapeutic development in the treatment of autoimmune diseases.
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Affiliation(s)
- Han Han
- Department of Biochemistry and Molecular Biology, Shenyang Medical College, No.146 North Huanghe St. Huanggu Dis, Shenyang City, Liaoning Pro 110034, China
| | - Weiqiang Zhou
- Department of Pathogen Biology, Shenyang Medical College, No.146 North Huanghe St. Huanggu Dis. Shenyang City, Liaoning Pro 110034, China
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6
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Kamel HFM, Nassir AM, Al Refai AA. Assessment of expression levels of leptin and leptin receptor as potential biomarkers for risk of prostate cancer development and aggressiveness. Cancer Med 2020; 9:5687-5696. [PMID: 32573960 PMCID: PMC7402836 DOI: 10.1002/cam4.3082] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 04/03/2020] [Accepted: 04/09/2020] [Indexed: 01/06/2023] Open
Abstract
Background Prostate cancer (PCa) is one of the most frequently diagnosed cancers worldwide. Despite the growing evidence associating obesity and adipokines, particularly leptin and its receptors, with cancer development and progression, it is still a debatable matter in PCa. Objectives We aimed to assess the role of leptin and its receptors as potential biomarkers for the risk of PCa development and aggressiveness. Methods In this study, 176 men were included and categorized according to an established histopathological diagnosis into three age‐ and BMI‐matched groups. The PCa group included 56 patients while the BPH group and the control group comprised 60 men each. Serum levels of total PSA (tPSA) were assessed by ELISA and mRNA expression levels of leptin and leptin receptors were assessed by RT‐PCR. Results Leptin and leptin receptor mRNA expression levels were significantly higher in PCa patients relative to BPH and to healthy control men. Both were overexpressed in PCa patients with aggressive and distantly metastasizing tumors compared to patients with confined tumors. Leptin receptor mRNA was an independent predictor of high Gleason score ≥ 7, distant metastasis, LN, and seminal vesicles invasion. Conclusion Leptin and its receptors are suggested to be potential biomarkers for PCa; leptin receptor mRNA might predict risk and aggressiveness of PCa.
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Affiliation(s)
- Hala Fawzy Mohamed Kamel
- Faculty of Medicine, Biochemistry Department, Umm Al-Qura University, Makkah, Saudi Arabia.,Faculty of Medicine, Medical Biochemistry Department, Ain Shams University, Cairo, Egypt
| | - Anmar M Nassir
- Urology Department, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Abeer A Al Refai
- Faculty of Medicine, Biochemistry Department, Umm Al-Qura University, Makkah, Saudi Arabia.,Faculty of Medicine, Medical Biochemistry and Molecular Biology Department, Menoufia University, Shebin Al-Kom, Egypt
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7
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Pakvasa M, Haravu P, Boachie-Mensah M, Jones A, Coalson E, Liao J, Zeng Z, Wu D, Qin K, Wu X, Luo H, Zhang J, Zhang M, He F, Mao Y, Zhang Y, Niu C, Wu M, Zhao X, Wang H, Huang L, Shi D, Liu Q, Ni N, Fu K, Lee MJ, Wolf JM, Athiviraham A, Ho SS, He TC, Hynes K, Strelzow J, El Dafrawy M, Reid RR. Notch signaling: Its essential roles in bone and craniofacial development. Genes Dis 2020; 8:8-24. [PMID: 33569510 PMCID: PMC7859553 DOI: 10.1016/j.gendis.2020.04.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 03/25/2020] [Accepted: 04/03/2020] [Indexed: 02/08/2023] Open
Abstract
Notch is a cell–cell signaling pathway that is involved in a host of activities including development, oncogenesis, skeletal homeostasis, and much more. More specifically, recent research has demonstrated the importance of Notch signaling in osteogenic differentiation, bone healing, and in the development of the skeleton. The craniofacial skeleton is complex and understanding its development has remained an important focus in biology. In this review we briefly summarize what recent research has revealed about Notch signaling and the current understanding of how the skeleton, skull, and face develop. We then discuss the crucial role that Notch plays in both craniofacial development and the skeletal system, and what importance it may play in the future.
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Affiliation(s)
- Mikhail Pakvasa
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Pritzker School of Medicine, University of Chicago, Chicago, IL 60637, USA.,Section of Plastic and Reconstructive Surgery, Department of Surgery, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Pranav Haravu
- Pritzker School of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Michael Boachie-Mensah
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Pritzker School of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Alonzo Jones
- Pritzker School of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Elam Coalson
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Pritzker School of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Junyi Liao
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Departments of Orthopaedic Surgery, Gastrointestinal Surgery, Obstetrics and Gynecology, and Nephrology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, PR China
| | - Zongyue Zeng
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Ministry of Education Key Laboratory of Diagnostic Medicine, and School of Laboratory and Diagnostic Medicine, Chongqing Medical University, Chongqing, 400016, PR China
| | - Di Wu
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Kevin Qin
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Xiaoxing Wu
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Departments of Orthopaedic Surgery, Gastrointestinal Surgery, Obstetrics and Gynecology, and Nephrology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, PR China
| | - Huaxiu Luo
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Department of Burn and Plastic Surgery, West China Hospital of Sichuan University, Chengdu, Sichuan, 610041, PR China
| | - Jing Zhang
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Departments of Orthopaedic Surgery, Gastrointestinal Surgery, Obstetrics and Gynecology, and Nephrology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, PR China
| | - Meng Zhang
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Department of Orthopaedic Surgery, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510405, PR China
| | - Fang He
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Departments of Orthopaedic Surgery, Gastrointestinal Surgery, Obstetrics and Gynecology, and Nephrology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, PR China
| | - Yukun Mao
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Departments of Orthopaedic Surgery and Neurosurgery, The Affiliated Zhongnan Hospital of Wuhan University, Wuhan, Hubei, 430072, PR China
| | - Yongtao Zhang
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Department of Orthopaedic Surgery, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, 266061, PR China
| | - Changchun Niu
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Department of Laboratory Diagnostic Medicine, Chongqing General Hospital, Chongqing, 400021, PR China
| | - Meng Wu
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Institute of Bone and Joint Research, and the Department of Orthopaedic Surgery, The Second Hospitals of Lanzhou University, Gansu, Lanzhou, 730030, PR China
| | - Xia Zhao
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Department of Orthopaedic Surgery, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, 266061, PR China
| | - Hao Wang
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Ministry of Education Key Laboratory of Diagnostic Medicine, and School of Laboratory and Diagnostic Medicine, Chongqing Medical University, Chongqing, 400016, PR China
| | - Linjuan Huang
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Departments of Orthopaedic Surgery, Gastrointestinal Surgery, Obstetrics and Gynecology, and Nephrology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, PR China
| | - Deyao Shi
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430072, PR China
| | - Qing Liu
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Department of Spine Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, PR China
| | - Na Ni
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Ministry of Education Key Laboratory of Diagnostic Medicine, and School of Laboratory and Diagnostic Medicine, Chongqing Medical University, Chongqing, 400016, PR China
| | - Kai Fu
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Departments of Orthopaedic Surgery and Neurosurgery, The Affiliated Zhongnan Hospital of Wuhan University, Wuhan, Hubei, 430072, PR China
| | - Michael J Lee
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Jennifer Moriatis Wolf
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Aravind Athiviraham
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Sherwin S Ho
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Tong-Chuan He
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Kelly Hynes
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Jason Strelzow
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Mostafa El Dafrawy
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Russell R Reid
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA.,Section of Plastic and Reconstructive Surgery, Department of Surgery, The University of Chicago Medical Center, Chicago, IL 60637, USA
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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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Luo J, Qi J, Wang W, Luo Z, Liu L, Zhang G, Zhou Q, Liu J, Peng X. Antiobesity Effect of Flaxseed Polysaccharide via Inducing Satiety due to Leptin Resistance Removal and Promoting Lipid Metabolism through the AMP-Activated Protein Kinase (AMPK) Signaling Pathway. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:7040-7049. [PMID: 31199141 DOI: 10.1021/acs.jafc.9b02434] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Obesity is a metabolic syndrome worldwide that causes many chronic diseases. Recently, we found an antiobesity effect of flaxseed polysaccharide (FP), but the mechanism remains to be elucidated. In this study, rats were first induced to develop obesity by being fed a high-fat diet. The obese rats were then fed a control diet, AIN-93M (group HFD), or a 10% FP diet (group FPD). The body weight, body fat, adipose tissue and liver sections, serous total triglycerides, levels of fasting blood glucose in serum, serous insulin, inflammatory cytokines in serum, and serous proteins within the leptin-neuropeptide Y (NPY) and AMP-activated protein kinase (AMPK) signaling pathway were determined and analyzed. FP intervention significantly reduced body weight and abdominal fat from 530 ± 16 g and 2.15% ± 0.30% in group HFD to 478 ± 10 g and 1.38% ± 0.48% in group FPD, respectively. This effect was achieved by removing leptin resistance possibly by inhibiting inflammation and recovering satiety through the significant downregulation of NPY and the upregulation of glucagon-like peptide 1. Adiponectin was then significantly upregulated probably via the gut-brain axis and further activated the AMPK signaling pathway to improve lipid metabolism including the improvement of lipolysis and fatty acid oxidation and the suppression of lipogenesis. This is the first report of the proposed antiobesity mechanism of FP, thereby providing a comprehensive understanding of nonstarch polysaccharides and obesity.
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Affiliation(s)
- Jianming Luo
- Department of Food Science and Engineering , Jinan University , Guangzhou , 510632 Guangdong , China
| | - Jiamei Qi
- College of Life Science and Technology , Jinan University , Guangzhou , 510632 Guangdong , China
| | - Wenjun Wang
- The Center for Precision Medicine of First Affiliated Hospital, Biomedical Translational Research Institute, School of Pharmacy , Jinan University , Guangzhou , 510632 Guangdong , China
| | - Zhenhuan Luo
- The Center for Precision Medicine of First Affiliated Hospital, Biomedical Translational Research Institute, School of Pharmacy , Jinan University , Guangzhou , 510632 Guangdong , China
| | - Liu Liu
- Department of Food Science and Engineering , Jinan University , Guangzhou , 510632 Guangdong , China
| | - Guangwen Zhang
- Department of Food Science and Engineering , Jinan University , Guangzhou , 510632 Guangdong , China
| | - Qinghua Zhou
- The Center for Precision Medicine of First Affiliated Hospital, Biomedical Translational Research Institute, School of Pharmacy , Jinan University , Guangzhou , 510632 Guangdong , China
| | - Jiesheng Liu
- College of Life Science and Technology , Jinan University , Guangzhou , 510632 Guangdong , China
| | - Xichun Peng
- Department of Food Science and Engineering , Jinan University , Guangzhou , 510632 Guangdong , China
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10
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Insights into leptin signaling and male reproductive health: the missing link between overweight and subfertility? Biochem J 2018; 475:3535-3560. [DOI: 10.1042/bcj20180631] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/28/2018] [Accepted: 10/19/2018] [Indexed: 12/24/2022]
Abstract
Obesity stands as one of the greatest healthcare challenges of the 21st century. Obesity in reproductive-age men is ever more frequent and is reaching upsetting levels. At the same time, fertility has taken an inverse direction and is decreasing, leading to an increased demand for fertility treatments. In half of infertile couples, there is a male factor alone or combined with a female factor. Furthermore, male fertility parameters such as sperm count and concentration went on a downward spiral during the last few decades and are now approaching the minimum levels established to achieve successful fertilization. Hence, the hypothesis that obesity and deleterious effects in male reproductive health, as reflected in deterioration of sperm parameters, are somehow related is tempting. Most often, overweight and obese individuals present leptin levels directly proportional to the increased fat mass. Leptin, besides the well-described central hypothalamic effects, also acts in several peripheral organs, including the testes, thus highlighting a possible regulatory role in male reproductive function. In the last years, research focusing on leptin effects in male reproductive function has unveiled additional roles and molecular mechanisms of action for this hormone at the testicular level. Herein, we summarize the novel molecular signals linking metabolism and male reproductive function with a focus on leptin signaling, mitochondria and relevant pathways for the nutritional support of spermatogenesis.
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11
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Khaki-Khatibi F, Mansouri F, Hajahmadipoorrafsanjani M, Ghojazadeh M, Gholikhani-Darbroud R. Study of rs1137101 polymorphism of leptin receptor gene with serum levels of selenium and copper in the patients of non-ST-segment elevation myocardial infarction (NSTEMI) in an Iranian population. Clin Biochem 2018; 60:64-70. [PMID: 29964004 DOI: 10.1016/j.clinbiochem.2018.06.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/22/2018] [Accepted: 06/24/2018] [Indexed: 01/21/2023]
Abstract
OBJECTIVE NSTEMI is a type of myocardial infarction (MI) causing partial but progressive occlusion of cardiac coronary vessels. The aim of this study was to investigate rs1137101 polymorphism of soluble leptin receptor (sLEPR) as well as circulatory selenium and copper levels in NSTEMI patients and their usefulness in analyzing susceptibility to NSTEMI. METHODS We collected sera and whole blood of 80 NSTEMI patients and 80 healthy individuals using cTnI levels plus electrocardiography as the "gold standard". Polymorphism analysis was done after DNA extraction by high-resolution melt PCR, selenium and copper levels by atomic absorption spectrophotometry, and sLEPR by ELISA. RESULTS AND DISCUTION There was Hardy-Weinberg (HWE) equilibrium for both patient and control loci (χ2 = 0.368434509 and 0.341447368, respectively). The frequencies of A/A, A/G, and G/G genotypes were 18 (22%), 37 (46%), and 25 (31%) for patients, and 30 (38%), 36 (45%), and 14 (18%) for healthy controls, respectively. The frequencies of A and G alleles were 73 (46%) and 87 (54%) for patients and 96 (60%) and 64 (40%) for control groups. There was correlation between allele G and sLEPR level and Body Mass Index (BMI). Selenium levels were lower in patient group than control group (66.307 ± 11.013 against 87.488 ± 11.839 μg/L; p < 0.001) but copper concentrations were higher (1.8105 ± 0.358 against 1.366 ± 0.454 mg/L; p < 0.001). sLEPR levels were also higher in patient than control group (30.568 ± 3.290 against 23.740 ± 5.457 ng/dL; p < .001). Low selenium and high copper concentration had positive diagnostic value for disease. CONCLUSION We find for the first time that there is a significant association between rs1137101 polymorphism and susceptibility to NSTEMI. There is also statistically meaningful association between decrease in serum selenium and increase in serum copper levels with susceptibility to NSTEMI.
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Affiliation(s)
- F Khaki-Khatibi
- Drug Applied Research Center and Department of Clinical Biochemistry, Tabriz University of Medical Sciences, Tabriz, Iran
| | - F Mansouri
- Cellular and Molecular Research Center and Department of Genetics and Immunology, Urmia University of Medical Sciences, Urmia, Iran
| | - M Hajahmadipoorrafsanjani
- Cardiology Department, Seyedoshohada Cardiovascular Medical Hospital, Urmia University of Medical Sciences, Urmia, Iran
| | - M Ghojazadeh
- Iranian Center for Evidence-Based Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - R Gholikhani-Darbroud
- Department of Clinical Biochemistry, Tabriz University of Medical Sciences, Tabriz, Iran.
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12
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Sudhakar M, Silambanan S, Chandran AS, Prabhakaran AA, Ramakrishnan R. C-Reactive Protein (CRP) and Leptin Receptor in Obesity: Binding of Monomeric CRP to Leptin Receptor. Front Immunol 2018; 9:1167. [PMID: 29910808 PMCID: PMC5992430 DOI: 10.3389/fimmu.2018.01167] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 05/09/2018] [Indexed: 02/04/2023] Open
Abstract
While leptin deficiency or dysfunction leads to morbid obesity, obese subjects are characterized paradoxically by hyperleptinemia indicating lack of response to leptin. C-reactive protein (CRP) has been suggested to be a key plasma protein that could bind to leptin. To examine whether CRP interferes with leptin action, mediated through its cell surface receptor, docking studies of CRP with the extracellular domain of the leptin receptor were done employing bioinformatics tools. Monomeric CRP docked with better Z-rank score and more non-bond interactions than pentameric CRP at the CRH2–FNIII domain proximal to the cell membrane, distinct from the leptin-docking site. Interaction of CRP with leptin receptor was validated by solid phase binding assay and co-immunoprecipitation of CRP and soluble leptin receptor (sOb R) from human plasma. Analysis of the serum levels of leptin, CRP, and sOb R by ELISA showed that CRP levels were significantly elevated (p < 0.0001) in non-morbid obese subjects (n = 42) compared to lean subjects (n = 32) and correlated positively with body mass index (BMI) (r = 0.74, p < 0.0001) and leptin (r = 0.8, p < 0.0001); levels of sOb R were significantly low in obese subjects (p < 0.001) and showed a negative correlation with BMI (r = −0.26, p < 0.05) and leptin (r = −0.23, p < 0.05) indicating a minimal role for sOb R in sequestering leptin.
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Affiliation(s)
- Manu Sudhakar
- Department of Biochemistry, Sri Ramachandra Medical College and Research Institute, Chennai, Tamil Nadu, India
| | - Santhi Silambanan
- Department of Biochemistry, Sri Ramachandra Medical College and Research Institute, Chennai, Tamil Nadu, India
| | - Abhinand S Chandran
- Department of Computational Biology and Bioinformatics, University of Kerala, Thiruvananthapuram, Kerala, India
| | - Athira A Prabhakaran
- Department of Computational Biology and Bioinformatics, University of Kerala, Thiruvananthapuram, Kerala, India
| | - Ramya Ramakrishnan
- Department of Surgery, Sri Ramachandra Medical College and Research Institute, Chennai, Tamil Nadu, India
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13
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Lei MM, Wei CK, Chen Z, Yosefi S, Zhu HX, Shi ZD. Anti-leptin receptor antibodies strengthen leptin biofunction in growing chickens. Gen Comp Endocrinol 2018; 259:223-230. [PMID: 29247679 DOI: 10.1016/j.ygcen.2017.12.005] [Citation(s) in RCA: 7] [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: 08/29/2017] [Revised: 12/13/2017] [Accepted: 12/13/2017] [Indexed: 12/11/2022]
Abstract
Antibodies against the extracellular domains of the chicken leptin receptor were used to study the biological function of leptin in growing chickens. Both polyclonal and monoclonal anti-LEPR antibodies were administered intramuscularly to 30-d-old Chinese indigenous Gushi pullets. Both antibody preparations increased feed intake for 6 h after injection and reduced plasma concentrations of glucose, triglycerides, and both high- and low-density lipoproteins. The antibody treatments also upregulated agouti-related peptide and neuropeptide Y in the hypothalamus and downregulated proopiomelanocortin, melanocortin 4 receptor, and leptin receptor. The treatments also upregulated leptin receptor, acetyl CoA carboxylase beta, and acyl-CoA oxidase in the liver, abdominal fat, and breast muscle and downregulated sterol regulatory element-binding protein-1 and fatty acid synthase. Furthermore, even though the anti-leptin receptor antibodies failed to affect leptin receptor signaling transduction when administered alone, they did augment the induction of leptin receptor signaling transduction by leptin. These results demonstrate that antibodies against the extracellular domains of leptin-specific receptor enhance, but do not mimic, the ability of leptin to activate receptors. Furthermore, the enhanced leptin bioactivity observed after the intramuscular injection of anti-LEPR antibodies confirmed the occurrence of de novo leptin in the peripheral tissues and blood of treated chickens.
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Affiliation(s)
- M M Lei
- Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, MOA, Nanjing 210014, China; Laboratory of Animal Breeding and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
| | - C K Wei
- Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, MOA, Nanjing 210014, China; Laboratory of Animal Breeding and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
| | - Z Chen
- Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, MOA, Nanjing 210014, China; Laboratory of Animal Breeding and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
| | - S Yosefi
- Institute of Animal Science, Agricultural Research Organization, Volcani Center, PO Box 6, Bet Dagan 50250, Israel.
| | - H X Zhu
- Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, MOA, Nanjing 210014, China; Laboratory of Animal Breeding and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
| | - Z D Shi
- Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, MOA, Nanjing 210014, China; Laboratory of Animal Breeding and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
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14
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Mandal A, Prabhavalkar KS, Bhatt LK. Gastrointestinal hormones in regulation of memory. Peptides 2018; 102:16-25. [PMID: 29466709 DOI: 10.1016/j.peptides.2018.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 02/13/2018] [Accepted: 02/14/2018] [Indexed: 12/16/2022]
Abstract
The connection between the gastrointestinal hormones and the brain has been established many years ago. This relation is termed the gut-brain axis (GBA). The GBA is a bidirectional communication which not only regulates gastrointestinal homeostasis but is also linked with higher emotional and cognitive functions. Hypothalamus plays a critical role in the regulation of energy metabolism, nutrient partitioning and control of feeding behaviors. Various gut hormones are released inside the gastrointestinal tract on food intake. These hormones act peripherally and influence the different responses of the tissues to the food intake, but do also have effects on the brain. The hypothalamus, in turn, integrates visceral function with limbic system structures such as hippocampus, amygdala, and cerebral cortex. The hippocampus has been known for its involvement in the cognitive function and the modulation of synaptic plasticity. This review aims to establish the role of various gut hormones in learning and memory, through the interaction of various receptors in the hippocampus. Understanding their role in memory can also aid in finding novel therapeutic strategies for the treatment of the neurological disorders associated with memory dysfunctions.
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Affiliation(s)
- Anwesha Mandal
- Department of Pharmacology, SVKM's Dr Bhanuben Nanavati College of Pharmacy, Vile Parle (W), Mumbai, India
| | - Kedar S Prabhavalkar
- Department of Pharmacology, SVKM's Dr Bhanuben Nanavati College of Pharmacy, Vile Parle (W), Mumbai, India.
| | - Lokesh K Bhatt
- Department of Pharmacology, SVKM's Dr Bhanuben Nanavati College of Pharmacy, Vile Parle (W), Mumbai, India
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15
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Wu L, Chen G, Liu W, Yang X, Gao J, Huang L, Guan H, Li Z, Zheng Z, Li M, Gu W, Ge L. Intramuscular injection of exogenous leptin induces adiposity, glucose intolerance and fatty liver by repressing the JAK2-STAT3/PI3K pathway in a rat model. Gen Comp Endocrinol 2017; 252:88-96. [PMID: 28242305 DOI: 10.1016/j.ygcen.2017.02.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 02/20/2017] [Accepted: 02/23/2017] [Indexed: 12/23/2022]
Abstract
Obesity, diabetes and fatty liver disease are extremely common in leptin-resistant patients. Dysfunction of leptin or its receptor is associated with obesity. The present study aimed to assess the effects of intramuscular injection of exogenous leptin or its receptor on fat deposition and leptin-insulin feedback regulation. Forty-five 40-day old female Sprague Dawley (SD) rats were injected thrice with leptin or its receptor intramuscularly. Adiposity and fat deposition were assessed by assessing the Lee's index, body weight, food intake, and total cholesterol, high density lipoprotein, low density lipoprotein, and triglyceride levels, as well as histological properties (liver and adipose tissue). Serum glucose, leptin, and insulin amounts were evaluated, and glucose tolerance assessed to monitor glucose metabolism in SD rats; pancreas specimens were analyzed immunohistochemically. Hypothalamic phosphorylated Janus kinase 2 (p-JAK2), phosphorylated signal transducer and activator of transcription 3 (p-STAT3), and phosphatidylinositol-3-kinase (PI3K) signaling, and hepatic sterol regulatory element binding protein-1 (SREBP-1) were qualified by Western blotting. Leptin receptor immunogen reduced fat deposition, increased appetite, and lowered serum leptin levels, enhancing STAT3 signaling in hypothalamus and down-regulating hepatic SREBP-1. In contrast, SD rats administered leptin immunogen displayed significantly increased body weight and fat deposition, with up-regulated SREBP-1, indicating adiposity occurrence. SD rats administered leptin immunogen also showed glucose intolerance, β- cell reduction in the pancreas, and deregulation of JAK2-STAT3/PI3K signaling, indicating that Lep rats were at risk of diabetes. In conclusion, intramuscular injection of exogenous leptin or its receptor, a novel rat model approach, can be used in obesity pathogenesis and therapeutic studies.
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Affiliation(s)
- Lihong Wu
- Key Laboratory of Oral Medicine, Guangzhou Institure of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China; Center of Emphasis in Infectious Diseases, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905, USA
| | - Guoxiong Chen
- First Department of Orthopedics, The Affiliated Nanhai Hospital of Southern Medical University, Foshan 528200, China
| | - Wen Liu
- Department of Laboratory Animal Center, Southern Medical University, Guangzhou 510515, China
| | - Xuechao Yang
- Key Laboratory of Oral Medicine, Guangzhou Institure of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China
| | - Jie Gao
- Key Laboratory of Oral Medicine, Guangzhou Institure of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China
| | - Liwen Huang
- Key Laboratory of Oral Medicine, Guangzhou Institure of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China
| | - Hongbing Guan
- Key Laboratory of Oral Medicine, Guangzhou Institure of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China
| | - Zhengmao Li
- Key Laboratory of Oral Medicine, Guangzhou Institure of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China
| | - Zhichao Zheng
- Key Laboratory of Oral Medicine, Guangzhou Institure of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China
| | - Meiling Li
- Key Laboratory of Oral Medicine, Guangzhou Institure of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China
| | - Weiwang Gu
- Department of Laboratory Animal Center, Southern Medical University, Guangzhou 510515, China; Department of Laboratory Animal Science, Songshan Lake Pearl Laboratory Animal Sci. & Tech. Co., Ltd., Dongguan 523808, China.
| | - Linhu Ge
- Key Laboratory of Oral Medicine, Guangzhou Institure of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China.
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16
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PTPRJ Inhibits Leptin Signaling, and Induction of PTPRJ in the Hypothalamus Is a Cause of the Development of Leptin Resistance. Sci Rep 2017; 7:11627. [PMID: 28912580 PMCID: PMC5599550 DOI: 10.1038/s41598-017-12070-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 09/04/2017] [Indexed: 12/17/2022] Open
Abstract
Leptin signaling in the hypothalamus plays a crucial role in the regulation of body weight. Leptin resistance, in which leptin signaling is disrupted, is a major obstacle to the improvement of obesity. We herein demonstrated that protein tyrosine phosphatase receptor type J (Ptprj) is expressed in hypothalamic neurons together with leptin receptors, and that PTPRJ negatively regulates leptin signaling by inhibiting the activation of JAK2, the primary tyrosine kinase in leptin signaling, through the dephosphorylation of Y813 and Y868 in JAK2 autophosphorylation sites. Leptin signaling is enhanced in Ptprj-deficient mice, and they exhibit lower weight gain than wild-type mice because of a reduced food intake. Diet-induced obesity and the leptin treatment up-regulated PTPRJ expression in the hypothalamus, while the overexpression of PTPRJ induced leptin resistance. Thus, the induction of PTPRJ is a factor contributing to the development of leptin resistance, and the inhibition of PTPRJ may be a potential strategy for improving obesity.
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17
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Abstract
Obesity, a major risk factor for the development of diabetes mellitus, cardiovascular diseases and certain types of cancer, arises from a chronic positive energy balance that is often due to unlimited access to food and an increasingly sedentary lifestyle on the background of a genetic and epigenetic vulnerability. Our understanding of the humoral and neuronal systems that mediate the control of energy homeostasis has improved dramatically in the past few decades. However, our ability to develop effective strategies to slow the current epidemic of obesity has been hampered, largely owing to the limited knowledge of the mechanisms underlying resistance to the action of metabolic hormones such as leptin and ghrelin. The development of resistance to leptin and ghrelin, hormones that are crucial for the neuroendocrine control of energy homeostasis, is a hallmark of obesity. Intensive research over the past several years has yielded tremendous progress in our understanding of the cellular pathways that disrupt the action of leptin and ghrelin. In this Review, we discuss the molecular mechanisms underpinning resistance to leptin and ghrelin and how they can be exploited as targets for pharmacological management of obesity.
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Affiliation(s)
- Huxing Cui
- Department of Pharmacology, University of Iowa, Iowa City, Iowa 52246, USA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa 52242, USA
| | - Miguel López
- Department of Physiology, Center for Research in Molecular Medicine and Chronic Diseases (CiMUS), University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain
- Centro de Investigación Biomédica en Red-Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela 15706, Spain
| | - Kamal Rahmouni
- Department of Pharmacology, University of Iowa, Iowa City, Iowa 52246, USA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa 52242, USA
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18
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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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19
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Abstract
Leptin is an adipose-derived cytokine that has an important role in bodyweight homeostasis and energy balance. There are a number of studies which have suggested that leptin and its receptors dysregulation play a critical role in the development of malignancies including hematological malignancies, mainly via activation of the JAK/STAT pathway which regulates downstream signaling pathways such as PI3K/AKT signaling and ERK1/2. In this review, current understandings of leptin/leptin receptors mediated pathogenesis in various lymphoid malignancies are described. Blocking of the leptin receptor might be a unique therapeutic approach for many hematological malignancies.
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Affiliation(s)
- Shahab Uddin
- a Translational Research Institute, Academic Health System, Hamad Medical Corporation , Doha , Qatar
| | - Ramzi M Mohammad
- a Translational Research Institute, Academic Health System, Hamad Medical Corporation , Doha , Qatar
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20
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21
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Scotece M, Mobasheri A. Leptin in osteoarthritis: Focus on articular cartilage and chondrocytes. Life Sci 2015; 140:75-8. [PMID: 26094910 DOI: 10.1016/j.lfs.2015.05.025] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 05/18/2015] [Accepted: 05/28/2015] [Indexed: 12/24/2022]
Abstract
Osteoarthritis (OA) is a complex joint disorder with a number of underlying physical, biochemical, biomechanical and genetic causes. Obesity is considered to be one of the major risk factors for the development and progression of OA. It actively contributes to the inflammatory status and to cartilage degradation in the OA joints. Recent data suggests that metabolic factors produced by white adipose tissue, such as leptin, may provide a mechanistic link between obesity and OA, providing an explanation for the high prevalence of OA among obese and over-weight individuals. The unbalanced production of catabolic and anabolic mediators by chondrocytes, the only cell type present in cartilage, determines cartilage degradation, which is the central pathological feature of OA. Evidence is accumulating to support a key role for leptin in the pathogenesis and/or progression of OA. The goal of this focused review is to summarize the current knowledge on the role of leptin in OA with particular emphasis on the effects of this adipokine in cartilage and chondrocyte pathophysiology.
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Affiliation(s)
- Morena Scotece
- SERGAS, Research Laboratory 9 (NEIRID LAB: Neuroendocrine Interactions in Rheumatology and Inflammatory Diseases), Institute of Medical Research (IDIS), Santiago University Clinical Hospital, Santiago de Compostela 15706, Spain; The D-BOARD European Consortium for Biomarker Discovery, Department of Veterinary Preclinical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom.
| | - Ali Mobasheri
- The D-BOARD European Consortium for Biomarker Discovery, Department of Veterinary Preclinical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom; Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, Arthritis Research UK Pain Centre, Medical Research Council and Arthritis Research UK Centre for Musculoskeletal Ageing Research, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom; Center of Excellence in Genomic Medicine Research (CEGMR), King Fahd Medical Research Center (KFMRC), King AbdulAziz University, Jeddah 21589, Saudi Arabia.
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22
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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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23
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Lei MM, Wu SQ, Shao XB, Li XW, Chen Z, Ying SJ, Shi ZD. Creating leptin-like biofunctions by active immunization against chicken leptin receptor in growing chickens. Domest Anim Endocrinol 2015; 50:55-64. [PMID: 25447880 DOI: 10.1016/j.domaniend.2014.09.001] [Citation(s) in RCA: 11] [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: 06/29/2014] [Revised: 09/01/2014] [Accepted: 09/04/2014] [Indexed: 12/19/2022]
Abstract
In this study, immunization against chicken leptin receptor (cLEPR) extracellular domain (ECD) was applied to investigate leptin regulation and LEPR biofunction in growing chicken pullets. A recombinant protein (cLEPR ECD) based on the cLEPR complemenary DNA sequence corresponding to the 582nd to 796th amino acid residues of cLEPR mature peptide was prepared and used as antigen. Immunization against cLEPR ECD in growing chickens increased anti-cLEPR ECD antibody titers in blood, enhanced proportions of phosphorylated janus kinase 2 (JAK2) and served as signal transducer and activator of transcription 3 (STAT3) protein in liver tissue. Chicken live weight gain and abdominal fat mass were significantly decreased (P < 0.05), but feed intake was stimulated by cLEPR ECD immunization (P < 0.05). The treatment also upregulated the gene expression levels of lepR, AMP-activated protein kinase (AMPK), acetyl CoA carboxylase-2 (ACC2), and uncoupling protein 3 (UCP3) in liver, abdominal fat, and breast muscle (P < 0.05) but decreased fasn expression levels (P < 0.01). Apart from that of lepR, the expression of appetite-regulating genes, such as orexigenic genes, agouti-related peptide (AgRP) and neuropeptide Y (NPY), were upregulated (P < 0.01), whereas the anorexigenic gene proopiomelanocortin (POMC) was downregulated in the hypothalamic tissue of cLEPR-immunized pullets (P < 0.01). Blood concentrations of metabolic molecules, such as glucose, triglycerides, and very-low-density lipoprotein, were significantly decreased in cLEPR-immunized pullets but those of cholesterol, high-density lipoprotein, and low-density lipoprotein increased. These results demonstrate that antibodies to membrane proximal cLEPR ECD enhance cLEPR signal transduction, which stimulates metabolism and reduces fat deposition in chickens.
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Affiliation(s)
- M M Lei
- Laboratory of Animal Breed Improvement and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - S Q Wu
- College of Animal Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - X B Shao
- Institute of Guagndong Province Poultry Technology, Guangzhou, 510520, China
| | - X W Li
- College of Animal Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Z Chen
- Laboratory of Animal Breed Improvement and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - S J Ying
- Laboratory of Animal Breed Improvement and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Z D Shi
- Laboratory of Animal Breed Improvement and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.
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Papanikolaou V, Stefanou N, Dubos S, Papathanasiou I, Palianopoulou M, Valiakou V, Tsezou A. Synergy of leptin/STAT3 with HER2 receptor induces tamoxifen resistance in breast cancer cells through regulation of apoptosis-related genes. Cell Oncol (Dordr) 2014; 38:155-64. [PMID: 25539992 DOI: 10.1007/s13402-014-0213-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2014] [Indexed: 01/09/2023] Open
Abstract
PURPOSE Tamoxifen is a major treatment modality for estrogen receptor positive breast cancer, but the occurrence of resistance remains a problem. Recently, obesity-related leptin has been found to interfere with tamoxifen in breast cancer MCF-7 cells. In the present study we investigated the effect of leptin on three tamoxifen-treated breast cancer cell types (i.e., MDA-MB-231, MCF-7 and MCF-7/HER2). METHODS The effect of tamoxifen/leptin treatment was evaluated using a MTT cell viability assay. mRNA expression was assessed by real time PCR and protein expression by Western blotting. WWOX, Survivin and BCL2 gene promoter activities were evaluated by chromatin immunoprecipitation. RESULTS Cell viability assays revealed that estrogen receptor negative MDA-MB-231 cells were resistant, that estrogen receptor positive MCF-7 cells were sensitive and that MCF-7/HER2 cells were relatively resistant to tamoxifen, while leptin co-administration 'rescued' MCF-7 and, especially, MCF-7/HER2 cells from the anti-proliferative effect of tamoxifen. The cell lines also exhibited a different phosphorylation status of STAT3, a transcription factor that is activated by the obesity related leptin receptor b (Ob-Rb). Most importantly, chromatin immunoprecipitation assays revealed differential STAT3 binding to the anti-apoptotic BCL2 and pro-apoptotic WWOX gene promoters in MCF-7 and MCF-7/HER2 cells, leading to concomitant modifications of its mRNA/protein expression levels, thus providing a selective advantage to HER2 over-expressing MCF-7/HER2 cells after treatment with tamoxifen and tamoxifen plus leptin. CONCLUSIONS Our study provides novel evidence indicating that synergy between the leptin/Ob-Rb/STAT3 signalling pathway and the HER2 receptor protects tamoxifen-treated HER2 over-expressing cells from the inhibitory effect of tamoxifen through differential regulation of apoptosis-related genes.
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Affiliation(s)
- Vassilis Papanikolaou
- Department of Biomedical Research and Technology, Institute for Research and Technology-Thessaly (I.RE.TE.TH), Centre for Research and Technology-Hellas (CE.R.T.H.), Larissa, 41222, Greece
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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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Abstract
Hypothalamic leptin action promotes negative energy balance and modulates glucose homeostasis, as well as serving as a permissive signal to the neuroendocrine axes that control growth and reproduction. Since the initial discovery of leptin 20 years ago, we have learned a great deal about the molecular mechanisms of leptin action. An important aspect of this has been the dissection of the cellular mechanisms of leptin signaling, and how specific leptin signals influence physiology. Leptin acts via the long form of the leptin receptor LepRb. LepRb activation and subsequent tyrosine phosphorylation recruits and activates multiple signaling pathways, including STAT transcription factors, SHP2 and ERK signaling, the IRS-protein/PI3Kinase pathway, and SH2B1. Each of these pathways controls specific aspects of leptin action and physiology. Important inhibitory pathways mediated by suppressor of cytokine signaling proteins and protein tyrosine phosphatases also limit physiologic leptin action. This review summarizes the signaling pathways engaged by LepRb and their effects on energy balance, glucose homeostasis, and reproduction. Particular emphasis is given to the multiple mouse models that have been used to elucidate these functions in vivo.
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Affiliation(s)
- Margaret B Allison
- Departments of Internal Medicineand Molecular and Integrative Physiology, University of Michigan, 1000 Wall Street, 6317 Brehm Tower, Ann Arbor, Michigan 48105, USA
| | - Martin G Myers
- Departments of Internal Medicineand Molecular and Integrative Physiology, University of Michigan, 1000 Wall Street, 6317 Brehm Tower, Ann Arbor, Michigan 48105, USA
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Guimond D, Diabira D, Porcher C, Bader F, Ferrand N, Zhu M, Appleyard SM, Wayman GA, Gaiarsa JL. Leptin potentiates GABAergic synaptic transmission in the developing rodent hippocampus. Front Cell Neurosci 2014; 8:235. [PMID: 25177272 PMCID: PMC4133691 DOI: 10.3389/fncel.2014.00235] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 07/26/2014] [Indexed: 12/17/2022] Open
Abstract
It is becoming increasingly clear that leptin is not only a hormone regulating energy homeostasis but also a neurotrophic factor impacting a number of brain regions, including the hippocampus. Although leptin promotes the development of GABAergic transmission in the hypothalamus, little is known about its action on the GABAergic system in the hippocampus. Here we show that leptin modulates GABAergic transmission onto developing CA3 pyramidal cells of newborn rats. Specifically, leptin induces a long-lasting potentiation (LLP-GABAA) of miniature GABAA receptor-mediated postsynaptic current (GABAA-PSC) frequency. Leptin also increases the amplitude of evoked GABAA-PSCs in a subset of neurons along with a decrease in the coefficient of variation and no change in the paired-pulse ratio, pointing to an increased recruitment of functional synapses. Adding pharmacological blockers to the recording pipette showed that the leptin-induced LLP-GABAA requires postsynaptic calcium released from internal stores, as well as postsynaptic MAPK/ERK kinases 1 and/or 2 (MEK1/2), phosphoinositide 3 kinase (PI3K) and calcium-calmodulin kinase kinase (CaMKK). Finally, study of CA3 pyramidal cells in leptin-deficient ob/ob mice revealed a reduction in the basal frequency of miniature GABAA-PSCs compared to wild type littermates. In addition, presynaptic GAD65 immunostaining was reduced in the CA3 stratum pyramidale of mutant animals, both results converging to suggest a decreased number of functional GABAergic synapses in ob/ob mice. Overall, these results show that leptin potentiates and promotes the development of GABAergic synaptic transmission in the developing hippocampus likely via an increase in the number of functional synapses, and provide insights into the intracellular pathways mediating this effect. This study further extends the scope of leptin's neurotrophic action to a key regulator of hippocampal development and function, namely GABAergic transmission.
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Affiliation(s)
- Damien Guimond
- Parc Scientifique de Luminy, Aix-Marseille Université Marseille, France ; Unité 901, Institut National de la Santé et de la Recherche Médicale Marseille, France ; Institut de Neurobiologie de la Méditerranée Marseille, France ; Program in Neuroscience, Department of Integrative Physiology and Neuroscience, Washington State University Pullman, WA, USA
| | - Diabe Diabira
- Parc Scientifique de Luminy, Aix-Marseille Université Marseille, France ; Unité 901, Institut National de la Santé et de la Recherche Médicale Marseille, France ; Institut de Neurobiologie de la Méditerranée Marseille, France
| | - Christophe Porcher
- Parc Scientifique de Luminy, Aix-Marseille Université Marseille, France ; Unité 901, Institut National de la Santé et de la Recherche Médicale Marseille, France ; Institut de Neurobiologie de la Méditerranée Marseille, France
| | - Francesca Bader
- Parc Scientifique de Luminy, Aix-Marseille Université Marseille, France ; Unité 901, Institut National de la Santé et de la Recherche Médicale Marseille, France ; Institut de Neurobiologie de la Méditerranée Marseille, France
| | - Nadine Ferrand
- Parc Scientifique de Luminy, Aix-Marseille Université Marseille, France ; Unité 901, Institut National de la Santé et de la Recherche Médicale Marseille, France ; Institut de Neurobiologie de la Méditerranée Marseille, France
| | - Mingyan Zhu
- Program in Neuroscience, Department of Integrative Physiology and Neuroscience, Washington State University Pullman, WA, USA
| | - Suzanne M Appleyard
- Program in Neuroscience, Department of Integrative Physiology and Neuroscience, Washington State University Pullman, WA, USA
| | - Gary A Wayman
- Program in Neuroscience, Department of Integrative Physiology and Neuroscience, Washington State University Pullman, WA, USA
| | - Jean-Luc Gaiarsa
- Parc Scientifique de Luminy, Aix-Marseille Université Marseille, France ; Unité 901, Institut National de la Santé et de la Recherche Médicale Marseille, France ; Institut de Neurobiologie de la Méditerranée Marseille, France
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The neuroanatomical function of leptin in the hypothalamus. J Chem Neuroanat 2014; 61-62:207-20. [PMID: 25007719 DOI: 10.1016/j.jchemneu.2014.05.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Revised: 05/09/2014] [Accepted: 05/28/2014] [Indexed: 02/07/2023]
Abstract
The anorexigenic hormone leptin plays an important role in the control of food intake and feeding-related behavior, for an important part through its action in the hypothalamus. The adipose-derived hormone modulates a complex network of several intercommunicating orexigenic and anorexigenic neuropeptides in the hypothalamus to reduce food intake and increase energy expenditure. In this review we present an updated overview of the functional role of leptin in respect to feeding and feeding-related behavior per distinct hypothalamic nuclei. In addition to the arcuate nucleus, which is a major leptin sensitive hub, leptin-responsive neurons in other hypothalamic nuclei, including the, dorsomedial-, ventromedial- and paraventricular nucleus and the lateral hypothalamic area, are direct targets of leptin. However, leptin also modulates hypothalamic neurons in an indirect manner, such as via the melanocortin system. The dissection of the complexity of leptin's action on the networks involved in energy balance is subject of recent and future studies. A full understanding of the role of hypothalamic leptin in the regulation of energy balance requires cell-specific manipulation using of conditional deletion and expression of leptin receptors. In addition, optogenetic and pharmacogenetic tools in combination with other pharmacological (such as the recent discovery of a leptin receptor antagonist) and neuronal tracing techniques to map the circuit, will be helpful to understand the role of leptin receptor expressing neurons. Better understanding of these circuits and the involvement of leptin could provide potential sites for therapeutic interventions in obesity and metabolic diseases characterized by dysregulation of energy balance.
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29
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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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30
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Lei MM, Wu SQ, Li XW, Wang CL, Chen Z, Shi ZD. Leptin receptor signaling inhibits ovarian follicle development and egg laying in chicken hens. Reprod Biol Endocrinol 2014; 12:25. [PMID: 24650216 PMCID: PMC3976635 DOI: 10.1186/1477-7827-12-25] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Accepted: 03/12/2014] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Nutrition intake during growth strongly influences ovarian follicle development and egg laying in chicken hens, yet the underlying endocrine regulatory mechanism is still poorly understood. The relevant research progress is hindered by difficulties in detection of leptin gene and its expression in the chicken. However, a functional leptin receptor (LEPR) is present in the chicken which has been implicated to play a regulatory role in ovarian follicle development and egg laying. The present study targeted LEPR by immunizing against its extracellular domain (ECD), and examined the resultant ovarian follicle development and egg-laying rate in chicken hens. METHODS Hens that have been immunized four times with chicken LEPR ECD were assessed for their egg laying rate and feed intake, numbers of ovarian follicles, gene expression profiles, serum lipid parameters, as well as STAT3 signaling pathway. RESULTS Administrations of cLEPR ECD antigen resulted in marked reductions in laying rate that over time eventually recovered to the levels exhibited by the Control hens. Together with the decrease in egg laying rate, cLEPR-immunized hens also exhibited significant reductions in feed intake, plasma concentrations of glucose, triglyceride, high-density lipoprotein, and low-density lipoprotein. Parallelled by reductions in feed intake, mRNA gene expression levels of AgRP, orexin, and NPY were down regulated, but of POMC, MC4R and lepR up-regulated in Immunized hen hypothalamus. cLEPR-immunization also promoted expressions of apoptotic genes such as caspase3 in theca and fas in granulosa layer, but severely depressed IGF-I expression in both theca and granulosa layers. CONCLUSIONS Immunization against cLEPR ECD in egg-laying hens generated antibodies that mimic leptin bioactivity by enhancing leptin receptor transduction. This up-regulated apoptotic gene expression in ovarian follicles, negatively regulated the expression of genes that promote follicular development and hormone secretion, leading to follicle atresia and interruption of egg laying. The inhibition of progesterone secretion due to failure of follicle development also lowered feed intake. These results also demonstrate that immunization against cLEPR ECD may be utilized as a tool for studying bio-functions of cLEPR.
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Affiliation(s)
- Ming M Lei
- Laboratory of Animal Breeding and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Si Q Wu
- College of Animal Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Xiao W Li
- College of Animal Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Cong L Wang
- College of Animal Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Zhe Chen
- Laboratory of Animal Breeding and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Zhen D Shi
- Laboratory of Animal Breeding and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
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31
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Adipokines as drug targets in joint and bone disease. Drug Discov Today 2014; 19:241-58. [DOI: 10.1016/j.drudis.2013.07.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 07/09/2013] [Accepted: 07/18/2013] [Indexed: 02/07/2023]
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32
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Caldefie-Chézet F, Dubois V, Delort L, Rossary A, Vasson MP. [Leptin: Involvement in the pathophysiology of breast cancer]. ANNALES D'ENDOCRINOLOGIE 2013; 74:90-101. [PMID: 23566612 DOI: 10.1016/j.ando.2013.03.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
More than one million new cases of breast cancer are diagnosed each year worldwide and more than 400,000 deaths occur due to this pathology. Obesity is a risk factor for postmenopausal breast cancer and the place held by the adipose tissue and secretions (i.e. adipokines) begins to be recognized. Indeed, firstly, plasma adipokine levels, modulated in obesity situation, could have effects "remotely" on mammary carcinogenesis and, secondly, breast cancer cells are surrounded by adipocyte microenvironment, which is probably more important in the case of obesity, and may be locally influenced by it. In this context, leptin appears to be strongly involved in mammary carcinogenesis and may contribute to the angiogenesis process and local pro-inflammatory mechanisms, especially in obese patients for whom increased metastatic potential and risk of mortality are described.
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Affiliation(s)
- Florence Caldefie-Chézet
- Clermont université, université d'Auvergne, UFR pharmacie, 28, place Henri-Dunant, 63000 Clermont-Ferrand, France.
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Jung CH, Kim MS. Molecular mechanisms of central leptin resistance in obesity. Arch Pharm Res 2013; 36:201-7. [DOI: 10.1007/s12272-013-0020-y] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Accepted: 12/24/2012] [Indexed: 02/06/2023]
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Page-Wilson G, Reitman-Ivashkov E, Meece K, White A, Rosenbaum M, Smiley RM, Wardlaw SL. Cerebrospinal fluid levels of leptin, proopiomelanocortin, and agouti-related protein in human pregnancy: evidence for leptin resistance. J Clin Endocrinol Metab 2013; 98:264-71. [PMID: 23118421 PMCID: PMC3537103 DOI: 10.1210/jc.2012-2309] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Leptin suppresses appetite by modulating the expression of hypothalamic neuropeptides including proopiomelanocortin (POMC) and agouti-related peptide (AgRP). Yet during pregnancy, caloric consumption increases despite elevated plasma leptin levels. DESIGN AND PARTICIPANTS To investigate this paradox, we measured leptin and soluble leptin receptor in plasma and leptin, POMC, and AgRP in cerebrospinal fluid (CSF) from 21 fasting pregnant women before delivery by cesarean section at a university hospital and from 14 fasting nonpregnant women. RESULTS Prepregnancy body mass index was 24.6 ± 1.1 (SE) vs. 31.3 ± 1.3 at term vs. 26.5 ± 1.6 kg/m(2) in controls. Plasma leptin (32.9 ± 4.6 vs. 16.7 ± 3.0 ng/ml) and soluble leptin receptor (30.9 ± 2.3 vs. 22.1 ± 1.4 ng/ml) levels were significantly higher in pregnant women. However, mean CSF leptin did not differ between the two groups (283 ± 34 vs. 311 ± 32 pg/ml), consistent with a relative decrease in leptin transport into CSF during pregnancy. Accordingly, the CSF/plasma leptin percentage was 1.0 ± 0.01% in pregnant subjects vs. 2.1 ± 0.2% in controls (P < 0.0001). Mean CSF AgRP was significantly higher in pregnant subjects (32.3 ± 2.7 vs. 23.5 ± 2.5 pg/ml; P = 0.03). Mean CSF POMC was not significantly different in pregnant subjects (200 ± 13.6 vs. 229 ± 17.3 fmol/ml; P = 0.190). However, the mean AgRP/POMC ratio was significantly higher among pregnant women (P = 0.003), consistent with an overall decrease in melanocortin tone favoring increased food intake during pregnancy. CONCLUSIONS These data demonstrate that despite peripheral hyperleptinemia, positive energy balance is achieved during pregnancy by a relative decrease in central leptin concentrations and resistance to leptin's effects on target neuropeptides that regulate energy balance.
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Tourkantonis I, Kiagia M, Peponi E, Tsagouli S, Syrigos KN. The Role of Leptin in Cancer Pathogenesis. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/jct.2013.42080] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Coppari R, Bjørbæk C. Leptin revisited: its mechanism of action and potential for treating diabetes. Nat Rev Drug Discov 2012; 11:692-708. [PMID: 22935803 PMCID: PMC4019022 DOI: 10.1038/nrd3757] [Citation(s) in RCA: 204] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Since the discovery of leptin in 1994, we now have a better understanding of the cellular and molecular mechanisms underlying its biological effects. In addition to its established anti-obesity effects, leptin exerts antidiabetic actions that are independent of its regulation of body weight and food intake. In particular, leptin can correct diabetes in animal models of type 1 and type 2 diabetes. In addition, long-term leptin replacement therapy improves glycaemic control, insulin sensitivity and plasma triglycerides in patients with severe insulin resistance due to lipodystrophy. These results have spurred enthusiasm for the use of leptin therapy to treat diabetes. Here, we review the current understanding of the glucoregulatory functions of leptin, emphasizing its central mechanisms of action and lessons learned from clinical studies, and discuss possible therapeutic applications of leptin in the treatment of type 1 and type 2 diabetes.
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Affiliation(s)
- Roberto Coppari
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas TX, 75390, USA
- Department of Cellular Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
- The Center for Epigenetics and Metabolism, University of California Irvine, Irvine, CA, 92697, USA
| | - Christian Bjørbæk
- Department of Medicine, Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston MA, 02215, USA
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Carpenter B, Hemsworth GR, Wu Z, Maamra M, Strasburger CJ, Ross RJ, Artymiuk PJ. Structure of the human obesity receptor leptin-binding domain reveals the mechanism of leptin antagonism by a monoclonal antibody. Structure 2012; 20:487-97. [PMID: 22405007 DOI: 10.1016/j.str.2012.01.019] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 01/13/2012] [Accepted: 01/22/2012] [Indexed: 11/16/2022]
Abstract
Leptin regulates energy homeostasis, fertility, and the immune system, making it an important drug target. However, due to a complete lack of structural data for the obesity receptor (ObR), leptin's mechanism of receptor activation remains poorly understood. We have crystallized the Fab fragment of a leptin-blocking monoclonal antibody (9F8), both in its uncomplexed state and bound to the leptin-binding domain (LBD) of human ObR. We describe the structure of the LBD-9F8 Fab complex and the conformational changes in 9F8 associated with LBD binding. A molecular model of the putative leptin-LBD complex reveals that 9F8 Fab blocks leptin binding through only a small (10%) overlap in their binding sites, and that leptin binding is likely to involve an induced fit mechanism. This crystal structure of the leptin-binding domain of the obesity receptor will facilitate the design of therapeutics to modulate leptin signaling.
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Affiliation(s)
- Byron Carpenter
- Academic Unit of Diabetes, Endocrinology and Reproduction, Department of Human Metabolism, University of Sheffield, Sheffield S10 2JF, UK
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Minoia M, Gentilin E, Molè D, Rossi M, Filieri C, Tagliati F, Baroni A, Ambrosio MR, degli Uberti E, Zatelli MC. Growth hormone receptor blockade inhibits growth hormone-induced chemoresistance by restoring cytotoxic-induced apoptosis in breast cancer cells independently of estrogen receptor expression. J Clin Endocrinol Metab 2012; 97:E907-16. [PMID: 22442272 DOI: 10.1210/jc.2011-3340] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT GH and IGF-I play a role in breast cancer (BC) development. We previously demonstrated that GH protects the estrogen receptor (ER) positive BC-derived MCF7 cell line toward the cytotoxic effects of doxorubicin (D), independently of IGF-I. This issue may be important in ER negative BC cells that are more aggressive and more likely to develop chemoresistance. AIM OF THE STUDY The aim of this study was to evaluate whether GH may impact chemoresistance phenotype of ER-negative BC-derived MDA-MB-231 cell line and investigate the possible mechanisms implicated in the protective action of GH toward the cytotoxic effects of D in both ER-positive and ER-negative BC-derived cell lines. RESULTS GH protects ER-negative MDA-MB-231 cells from the cytotoxic effects of D and GH receptor antagonist pegvisomant reduces GH-induced DNA synthesis also in these cells. In both MDA-MB-231 and MCF7 cells, GH does not revert D-induced G2/M accumulation but significantly reduces basal and D-induced apoptosis, an effect blocked by pegvisomant. Glutathione S-transferase activity is not implicated in the protective effects of GH, whereas D-induced apoptosis depends on c-Jun N terminal kinase (JNK) activation. GH reduces both basal and D-stimulated JNK transcriptional activity and phosphorylation. CONCLUSIONS In human BC cell lines, GH directly promotes resistance to apoptosis induced by chemotherapeutic drugs independently of ER expression by modulating JNK, further broadening the concept that GH excess may hamper cytotoxic BC treatment. These findings support the hypothesis that blocking GH receptor may be viewed as a potential new therapeutic approach to overcome chemoresistance, especially in ER-negative BC.
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Affiliation(s)
- Mariella Minoia
- Section of Endocrinology, Department of Biomedical Sciences and Advanced Therapies, University of Ferrara, Via Savonarola 9, 44121 Ferrara, Italy
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Marie CS, Verkerke HP, Paul SN, Mackey AJ, Petri WA. Leptin protects host cells from Entamoeba histolytica cytotoxicity by a STAT3-dependent mechanism. Infect Immun 2012; 80:1934-43. [PMID: 22331430 PMCID: PMC3347425 DOI: 10.1128/iai.06140-11] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 01/29/2012] [Indexed: 11/20/2022] Open
Abstract
The adipocytokine leptin links nutritional status to immune function. Leptin signaling protects from amebiasis, but the molecular mechanism is not understood. We developed an in vitro model of ameba-host cell interaction to test the hypothesis that leptin prevents ameba-induced apoptosis in host epithelial cells. We demonstrated that activation of mammalian leptin signaling increased cellular resistance to amebic cytotoxicity, including caspase-3 activation. Exogenous expression of the leptin receptor conferred resistance in susceptible cells, and leptin stimulation enhanced protection. A series of leptin receptor signaling mutants showed that resistance to amebic cytotoxicity was dependent on activation of STAT3 but not the Src homology-2 domain-containing tyrosine phosphatase (SHP-2) or STAT5. A common polymorphism in the leptin receptor (Q223R) that increases susceptibility to amebiasis in humans and mice was found to increase susceptibility to amebic cytotoxicity in single cells. The Q223R polymorphism also decreased leptin-dependent STAT3 activation by 21% relative to that of the wild-type (WT) receptor (P = 0.035), consistent with a central role of STAT3 signaling in protection. A subset of genes uniquely regulated by STAT3 in response to leptin was identified. Most notable were the TRIB1 and suppressor of cytokine signaling 3 (SOCS3) genes, which have opposing roles in the regulation of apoptosis. Overall apoptotic genes were highly enriched in this gene set (P < 1E-05), supporting the hypothesis that leptin regulation of host apoptotic genes via STAT3 is responsible for protection. This is the first demonstration of a mammalian signaling pathway that restricts amebic pathogenesis and represents an important advance in our mechanistic understanding of how leptin links nutrition and susceptibility to infection.
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Affiliation(s)
- Chelsea S Marie
- Biology Department, Drew University, Madison, New Jersey, USA.
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Biener E, Charlier M, Ramanujan VK, Daniel N, Eisenberg A, Bjørbaek C, Herman B, Gertler A, Djiane J. Quantitative FRET imaging of leptin receptor oligomerization kinetics in single cells. Biol Cell 2012; 97:905-19. [PMID: 15771593 DOI: 10.1042/bc20040511] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND INFORMATION Leptin, an adipocyte-secreted hormone, signals through activation of its membrane-embedded receptor (LEPR). To study the leptin-induced events occurring in short (LEPRa) and long (LEPRb) LEPRs in the cell membrane, by FRET (fluorescence resonance energy transfer) methodology, the respective receptors, tagged at their C-terminal with CFP (cyan fluorescent protein) or YFP (yellow fluorescent protein), were prepared. RESULTS The constructs encoding mLEPRa (mouse LEPRa)-YFP and mLEPRa-CFP, mLEPRb-YFP and mLEPRb-CFP were tested for biological activity in transiently transfected CHO cells (Chinese-hamster ovary cells) and HEK-293T cells (human embryonic kidney 293 T cells) for activation of STAT3 (signal transduction and activators of transcription 3)-mediated LUC (luciferase) activity and binding of radiolabelled leptin. All four constructs were biologically active and were as potent as their untagged counterparts. The localization pattern of the fused protein appeared to be confined almost entirely to the cell membrane. The leptin-dependent interaction between various types of receptors in fixed cells were studied by measuring FRET, using fluorescence lifetime imaging microscopy and acceptor photobleaching methods. CONCLUSIONS Both methods yielded similar results, indicating that (1) leptin receptors expressed in the cell membrane exist mostly as preformed LEPRa/LEPRa or LEPRb/LEPRb homo-oligomers but not as LEPRb/LEPRa hetero-oligomers; (2) the appearance of transient leptin-induced FRET in cells transfected with LEPRb/LEPRb reflects both a conformational change that leads to closer interaction in the cytosolic part and a higher FRET signal, as well as de novo homo-oligomerization; (3) in LEPRa/LEPRa, exposure to leptin does not lead to any increase in FRET signalling as the proximity of CFP and YFP fluorophores in space already gives maximal FRET efficiency of the preoligomerized receptors.
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Affiliation(s)
- Eva Biener
- The 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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Abstract
Leptin is a well-known mediator of obesity. Leptin and its receptor are overexpressed in breast cancer, especially in high-grade tumors. It has an association with progression and poor survival of breast cancer. Leptin can regulate endothelial cell proliferation and promote angiogenesis. There are several other factors such as insulin and HER2 may be involved in the relationship between leptin and breast cancer. Leptin system has emerged as a new and promising therapeutic target for breast cancer. This review article summarizes the current knowledge about the relation of leptin and breast cancer.
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42
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Manzar D, Hussain ME. Leptin rhythmicity and its relationship with other rhythm markers. BIOL RHYTHM RES 2011. [DOI: 10.1080/09291011003759558] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Saukko M, Kesäniemi YA, Ukkola O. Leptin receptor Lys109Arg and Gln223Arg polymorphisms are associated with early atherosclerosis. Metab Syndr Relat Disord 2011; 8:425-30. [PMID: 20874424 DOI: 10.1089/met.2010.0004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Leptin is a hormone expressed by the leptin gene, primarily in adipocytes, controlling food intake and energy expenditure. The effects of leptin are mediated by its receptor (LEPR) located in the central nervous system and other tissues, including adipocytes and endothelial cells. The aim of this study was to characterize two polymorphisms of LEPR, Lys109Arg (rs1137100) and Gln223Arg (rs1137101), as risk factors for early atherosclerosis. This connection has not been studied before. METHODS This study was performed in the randomly selected, middle-aged control subjects (n=526) from our well-defined OPERA (Oulu Project Elucidating Risk of Atherosclerosis) study. Analysis of covariance (ANCOVA) was performed to study the associations between genotypes, intima media thickness (IMT) measurements, and risk factors for atherosclerosis. RESULTS Subjects with the genotype Lys109Arg had the lowest body mass index (BMI) (P = 0.035), whereas Arg109Arg homozygotes had the highest total cholesterol (P=0.021) when adjusted for sex and age. Gln223Arg associated independently with systolic blood pressure (P=0.036). There were no differences in leptin concentrations between the genotypes. The adjusted (sex, age, BMI, smoking status, low-density lipoprotein cholesterol, systolic blood pressure, and fasting blood glucose) means for the IMT measurements were lowest in the Arg109 and Arg223 homozygotes (P=0.042 and P=0.041, ANCOVA, respectively). CONCLUSIONS The variations in the LEPR gene are independently associated with early atherosclerosis and some of its risk factors. These variations could possibly affect leptin signaling and thereby modify the effects of leptin on the atherosclerotic process.
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Affiliation(s)
- Meiju Saukko
- Institute of Clinical Medicine, Department of Internal Medicine and Biocenter Oulu, University of Oulu and Clinical Research Center, Oulu University Hospital, Oulu, Finland
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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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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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Mao X, Zeng X, Wang J, Qiao S. Leucine promotes leptin receptor expression in mouse C2C12 myotubes through the mTOR pathway. Mol Biol Rep 2010; 38:3201-6. [PMID: 20151325 DOI: 10.1007/s11033-010-9992-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 02/03/2010] [Indexed: 11/24/2022]
Abstract
Leptin plays a critical role in regulating muscle protein metabolism by binding with leptin receptors in a 1:1 stoichiometry. However, the role for leucine in the regulation of leptin receptor expression in muscle has not been investigated. The present study was conducted to test the hypothesis that leucine regulates leptin receptor levels in C2C12 myotubes. Cells were cultured in the presence of DMEM/F12 medium containing supplemental 0 or 5 mM L: -leucine. Leptin receptor expression by C2C12 myotubes peaked at 2 h post-supplementation. Additionally, leucine stimulated leptin receptor expression at both mRNA and protein levels in a dose-dependent manner. Furthermore, leucine enhanced the phosphorylation of mammalian target of rapamycin (mTOR). Addition of rapamycin (an inhibitor of mTOR) to culture medium completely suppressed leucine-induced activation of mTOR and inhibited leucine-stimulated leptin receptor production. These results indicate that leucine affects leptin receptor expression in muscle cells via the mTOR signaling pathway.
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Affiliation(s)
- Xiangbing Mao
- State Key Laboratory on Animal Nutrition, China Agricultural University, No. 2. Yuanmingyuan West Road, 100193 Beijing, China
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Abstract
The brain controls energy homeostasis and body weight by integrating various metabolic signals. Leptin, an adipose-derived hormone, conveys critical information about peripheral energy storage and availability to the brain. Leptin decreases body weight by both suppressing appetite and promoting energy expenditure. Leptin directly targets hypothalamic neurons, including AgRP and POMC neurons. These leptin-responsive neurons widely connect to other neurons in the brain, forming a sophisticated neurocircuitry that controls energy intake and expenditure. The anorexigenic actions of leptin are mediated by LEPRb, the long form of the leptin receptor, in the hypothalamus. LEPRb activates both JAK2-dependent and -independent pathways, including the STAT3, PI 3-kinase, MAPK, AMPK, and mTOR pathways. These pathways act coordinately to form a network that fully mediates leptin response. LEPRb signaling is regulated by both positive (e.g., SH2B1) and negative (e.g., SOCS3 and PTP1B) regulators and by endoplasmic reticulum stress. Leptin resistance, a primary risk factor for obesity, likely results from impairment in leptin transport, LEPRb signaling, and/or the neurocircuitry of energy balance.
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Affiliation(s)
- David L Morris
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Mchigan 48109-0622, USA
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Cirillo D, Rachiglio AM, la Montagna R, Giordano A, Normanno N. Leptin signaling in breast cancer: an overview. J Cell Biochem 2009; 105:956-64. [PMID: 18821585 DOI: 10.1002/jcb.21911] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The adipocyte-derived peptide leptin acts through binding to specific membrane receptors, of which six isoforms (obRa-f) have been identified up to now. Binding of leptin to its receptor induces activation of different signaling pathways, including the JAK/STAT, MAPK, IRS1, and SOCS3 signaling pathways. Since the circulating levels of leptin are elevated in obese individuals, and excess body weight has been shown to increase breast cancer risk in postmenopausal women, several studies addressed the role of leptin in breast cancer. Expression of leptin and its receptors has been demonstrated to occur in breast cancer cell lines and in human primary breast carcinoma. Leptin is able to induce the growth of breast cancer cells through activation of the Jak/STAT3, ERK1/2, and/or PI3K pathways, and can mediate angiogenesis by inducing the expression of vascular endothelial growth factor (VEGF). In addition, leptin induces transactivation of ErbB-2, and interacts in triple negative breast cancer cells with insulin like growth factor-1 (IGF-1) to transactivate the epidermal growth factor receptor (EGFR), thus promoting invasion and migration. Leptin can also affect the growth of estrogen receptor (ER)-positive breast cancer cells, by stimulating aromatase expression and thereby increasing estrogen levels through the aromatization of androgens, and by inducing MAPK-dependent activation of ER. Taken together, these findings suggest that the leptin system might play an important role in breast cancer pathogenesis and progression, and that it might represent a novel target for therapeutic intervention in breast cancer.
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Affiliation(s)
- Donatella Cirillo
- Protein Chemistry Laboratory, Centro di Ricerche Oncologiche di Mercogliano-CROM, Mercogliano (AV), Italy
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Procaccini C, Lourenco EV, Matarese G, La Cava A. Leptin signaling: A key pathway in immune responses. ACTA ACUST UNITED AC 2009; 4:22-30. [PMID: 19774101 DOI: 10.2174/157436209787048711] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Leptin is a hormone whose central role is to regulate endocrine functions and to control energy expenditure. After the discovery that leptin can also have pro-inflammatory effects, several studies have tried to address - at the molecular level - the pathways involved in leptin-induced modulation of the immune functions in normal and pathologic conditions. The signaling events influenced by leptin after its binding to the leptin receptor have been under scrutiny in the past few years, and considerable experimental work has elucidated the consequences of leptin effects on immune cells. This review examines the biochemistry, function and regulation of leptin signaling in view of possible intervention on this molecule for a better management and therapy of immune-mediated diseases.
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Affiliation(s)
- Claudio Procaccini
- Department of Medicine, University of California Los Angeles, Los Angeles, California 90095
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