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Abstract
MicroRNAs (miRNAs) regulate osteogenic differentiation and influence osteoporosis (OP). The aim of this study was to determine the potential role of miR-874-3p in OP. The expression levels of miR-874-3p and leptin (LEP) in the femoral neck trabeculae of 35 patients with or without OP were measured by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The effects of miR-874-3p or LEP on the cell proliferation and alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), and osterix (OSX) levels were observed by upregulating miR-874-3p in human bone marrow mesenchymal stem cells (hBMSCs). Additionally, calcium deposition levels were evaluated using alizarin red staining (ARS). Molecular mechanisms of miR-874-3p and LEP underlying the osteogenic differentiation of hBMSCs were also evaluated using bioinformatics analysis, luciferase reporter assays, and RNA pull-down assays. The miR-874-3p levels were significantly lower in the femoral neck trabeculae of patients with OP than those of the control group, while the opposite was observed regarding the levels of LEP. Expression levels of miR-874-3p in hBMSCs were upregulated during osteogenic differentiation, while those of LEP were downregulated. Moreover, miR-874-3p upregulation promoted ALP, RUNX2, OCN, and OSX mRNA expression, cell proliferation, and calcium deposition in hBMSCs. LEP was found to be a target gene of miR-874-3p. Overexpression of LEP inhibited the expression of osteoblast markers and reversed the effect of osteogenic differentiation induced by the upregulation of miR-874-3p. In conclusion, miR-874-3p promoted the proliferation and differentiation of hBMSCs by downregulating the expression of LEP, thus inhibiting OP. Abbreviations : miRNAs: microRNAs; OP: osteoporosis; hBMSCs: human Bone Marrow Mesenchymal stem cells; LEP: leptin; DEGs: differentially expressed genes
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Affiliation(s)
- Ling Mei
- Department of Orthopedic, Wuhan Hospital of Traditional Chinese Medicine, Wuhan, Hubei, China
| | - Min Li
- Department of Cardiovascular, Wuhan Hospital of Traditional Chinese Medicine, Wuhan, Hubei, China
| | - Tao Zhang
- The First Clinical Medical College, Hubei University of Chinese Medicines, Wuhan, Hubei, China
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Feng H, Zhang Q, Zhao Y, Zhao L, Shan B. Leptin acts on mesenchymal stem cells to promote chemoresistance in osteosarcoma cells. Aging (Albany NY) 2020; 12:6340-6351. [PMID: 32289750 PMCID: PMC7185129 DOI: 10.18632/aging.103027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 02/27/2020] [Indexed: 04/17/2023]
Abstract
Leptin signaling influences osteoblastogenesis and modulates the fate of mesenchymal stem cells (MSCs) during bone and cartilage regeneration. Although MSCs abound in the osteosarcoma (OS) microenvironment, and leptin exhibits pro-tumorigenic properties, leptin's influence on OS progression and chemoresistant signaling in MSCs remains unclear. Using cell viability and apoptosis assays, we showed that medium conditioned by leptin-treated human MSCs promotes cisplatin resistance in cultured human OS cells. Moreover, GFP-LC3 expression and chloroquine treatment experiments showed that this effect is mediated by stimulation of autophagy in OS cells. TGF-β expression in MSCs was upregulated by leptin and suppressed by leptin receptor knockdown. Silencing TGF-β in MSCs also abolished OS cell chemoresistance induced by leptin-conditioned medium. Cisplatin resistance was also induced when leptin-conditioned MSCs were co-injected with MG-63 OS cells to generate subcutaneous xenografts in nude mice. Finally, we observed a significant correlation between autophagy-associated gene expression in OS clinical samples and patient prognosis. We conclude that leptin upregulates TGF-β in MSCs, which promotes autophagy-mediated chemoresistance in OS cells.
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Affiliation(s)
- Helin Feng
- Department of Orthopedics, The Fourth Hospital of Hebei Medical University, Shijiazhuang 050011, Hebei, China
- Postdoctoral Mobile Station, Hebei Medical University, Shijiazhuang 050017, Hebei, China
- Hebei Province Xingtai People’s Hospital Postdoctoral Workstation, Xingtai 054031, Hebei, China
| | - Qianqian Zhang
- Department of Gynecology, Hebei Medical University Second Affiliated Hospital, Shijiazhuang 050000, Hebei, China
| | - Yi Zhao
- Department of Orthopedics, The Fourth Hospital of Hebei Medical University, Shijiazhuang 050011, Hebei, China
| | - Lili Zhao
- Hebei Province Xingtai People’s Hospital Postdoctoral Workstation, Xingtai 054031, Hebei, China
| | - Baoen Shan
- Postdoctoral Mobile Station, Hebei Medical University, Shijiazhuang 050017, Hebei, China
- Research Centre, The Fourth Hospital of Hebei Medical University, Shijiazhuang 050011, Hebei, China
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Al-Shibli SM, Harun N, Ashour AE, Mohd Kasmuri MHB, Mizan S. Expression of leptin and leptin receptors in colorectal cancer-an immunohistochemical study. PeerJ 2019; 7:e7624. [PMID: 31592340 PMCID: PMC6778430 DOI: 10.7717/peerj.7624] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 08/06/2019] [Indexed: 01/22/2023] Open
Abstract
Obesity is demonstrated to be a risk factor in the development of cancers of various organs, such as colon, prostate, pancreas and so on. Leptine (LEP) is the most renowned of the adipokines. As a hormone, it mediates its effect through leptin receptor (LEPR), which is widely expressed in various tissues including colon mucosa. In this study, we have investigated the degree of expression of LEP and LEPR in colorectal cancer (CRC). We collected 44 surgically resected colon cancer tissues along with normal adjacent colon tissue (NACT) from a sample of CRC patients from the Malaysian population and looked for leptin and leptin receptors using immunohistochemistry (IHC). All the samples showed low presence of both LEP and LEPR in NACT, while both LEP and LEPR were present at high intensity in the cancerous tissues with 100% and 97.7% prevalence, respectively. Both were sparsed in the cytoplasm and were concentrated beneath the cell membrane. However, we did not find any significant correlation between their expression and pathological parameters like grade, tumor size, and lymph node involvement. Our study further emphasizes the possible causal role of LEP and LEPR with CRC, and also the prospect of using LEPR as a possible therapeutic target.
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Affiliation(s)
- Saad M Al-Shibli
- Department of Basic Medical Sciences, International Islamic University, Kuantan, Pahang, Malaysia
| | - Norra Harun
- Pathology Department, Hospital Tengku Ampuan Afzan, Kuantan, Pahang, Malaysia
| | - Abdelkader E Ashour
- Department of Basic Medical Sciences, International Islamic University, Kuantan, Pahang, Malaysia
| | - Mohd Hanif B Mohd Kasmuri
- Department of Pathology & Laboratory Medicine, International Islamic University, Kuantan, Pahang, Malaysia
| | - Shaikh Mizan
- Department of Basic Medical Sciences, International Islamic University, Kuantan, Pahang, Malaysia
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Giovannone D, Paul S, Schindler S, Arata C, Farmer DT, Patel P, Smeeton J, Crump JG. Programmed conversion of hypertrophic chondrocytes into osteoblasts and marrow adipocytes within zebrafish bones. eLife 2019; 8:42736. [PMID: 30785394 PMCID: PMC6398980 DOI: 10.7554/elife.42736] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 02/13/2019] [Indexed: 01/10/2023] Open
Abstract
Much of the vertebrate skeleton develops from cartilage templates that are progressively remodeled into bone. Lineage tracing studies in mouse suggest that chondrocytes within these templates persist and become osteoblasts, yet the underlying mechanisms of this process and whether chondrocytes can generate other derivatives remain unclear. We find that zebrafish cartilages undergo extensive remodeling and vascularization during juvenile stages to generate fat-filled bones. Growth plate chondrocytes marked by sox10 and col2a1a contribute to osteoblasts, marrow adipocytes, and mesenchymal cells within adult bones. At the edge of the hypertrophic zone, chondrocytes re-enter the cell cycle and express leptin receptor (lepr), suggesting conversion into progenitors. Further, mutation of matrix metalloproteinase 9 (mmp9) results in delayed growth plate remodeling and fewer marrow adipocytes. Our data support Mmp9-dependent growth plate remodeling and conversion of chondrocytes into osteoblasts and marrow adipocytes as conserved features of bony vertebrates. Our adult bones are made of a fatty tissue, called marrow, wrapped inside a hard outer layer produced by bone cells. They may appear stiff and unyielding, but our bones are actually dynamic structures. Early in life, most bones start as small ‘templates’ made of another, flexible tissue called cartilage. As the templates grow into adult bones, the cartilage is gradually replaced by bone and fat, but this process is still poorly understood. For example, it is not clear whether cartilage cells simply die and make way for new cells, or instead if they turn into bone and fat cells. To investigate this question, Giovannone, Paul et al. set out to follow the fate of early cartilage cells in zebrafish, and to compare this with what happens in mammals. Zebrafish were chosen because their skeleton and ours develop in similar ways; yet, these animals are much easier to study, in particular because their embryos are transparent. Young cartilage cells were ‘tagged’ with a long-lasting fluorescent protein in genetically engineered zebrafish embryos, and then followed over time. As the embryos started to form bones, the cartilage cells gave rise to bone cells, fat cells, and also potentially adult stem cells within the marrow, which can become other types of cells. This process required a protein called Mmp9, which also helps shape bone development in other organisms, including humans. Defects in how early cartilage templates morph into bone and fat may contribute to dwarfism and other severe conditions. Fully grasping the molecular mechanisms that preside over this complex transition may one day help design drugs to treat skeletal disorders.
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Affiliation(s)
- Dion Giovannone
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, United States
| | - Sandeep Paul
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, United States
| | - Simone Schindler
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, United States
| | - Claire Arata
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, United States
| | - D'Juan T Farmer
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, United States
| | - Punam Patel
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, United States
| | - Joanna Smeeton
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, United States
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Abstract
Leptin originates in adipocytes, including those in bone marrow, and circulates in concentrations 20 to 90 times higher than those in the cerebrospinal fluid. It has direct anabolic effects on osteoblasts and chondrocytes, but it also influences bone indirectly, via the hypothalamus and sympathetic nervous system, via changes in body weight, and via effects on the production of other hormones (e.g., pituitary). Leptin's role in bone physiology is determined by the balance of these conflicting effects. Reflecting this inconsistency, the leptin-deficient mouse has reduced length and bone mineral content of long bones but increased vertebral trabecular bone. A consistent bone phenotype in human leptin deficiency has not been established. Systemic leptin administration in animals and humans usually exerts a positive effect on bone mass, and leptin administration into the cerebral ventricles usually normalizes the bone phenotype in leptin-deficient mice. Reflecting the role of the sympathetic nervous system in mediating the central catabolic effects of leptin on the skeleton, β-adrenergic agonists and antagonists have major effects on bone in mice, but this is not consistently seen in humans. The balance of the central and peripheral effects of leptin on bone remains an area of substantial controversy and might vary between species and according to other factors such as body weight, baseline circulating leptin levels, and the presence of specific pathologies. In humans, leptin is likely to contribute to the positive relationship observed between adiposity and bone density, which allows the skeleton to respond appropriately to changes in soft tissue mass.
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Affiliation(s)
- Ian R Reid
- University of Auckland, Auckland, New Zealand.,Department of Endocrinology, Auckland District Health Board, Auckland, New Zealand
| | - Paul A Baldock
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
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Wu Z, Shao P, Dass CR, Wei Y. Systemic leptin administration alters callus VEGF levels and enhances bone fracture healing in wildtype and ob/ob mice. Injury 2018; 49:1739-1745. [PMID: 30244701 DOI: 10.1016/j.injury.2018.06.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 05/05/2018] [Accepted: 06/30/2018] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Leptin's role in bone formation has been reported, however, its mechanism of affecting bone metabolism is remaining unclear. In this study, we aimed to test whether leptin has a positive effect on fracture healing through the possible mechanism of increasing vascular endothelial growth factor (VEGF) expression in callus tissue. METHODS Standardized femur fractures were created in leptin-deficient ob/ob and wildtype C57BL/6J mice, and recombinant mouse leptin or its vehicle (physiological saline) was administered intraperitoneally during the study. Body weight, radiological, histologic and immunoblotting analyses were performed at different stages of fracture healing. KEY FINDINGS The results showed that leptin treatment led to lower rate of body weight change in both mice genotypes. Radiological and histological analyses showed that the experimental groups had better fracture healing at 14, 21 and 28 days compared to the control groups. Leptin-treated groups had significantly higher VEGF expression in callus compared with the control groups at 2 and 3 weeks post-fracture except normal mice at 2 weeks, and leptin-deficient mice had higher VEGF levels in calluses than normal mice at the same timepoint. CONCLUSION Low-dose systemically-administered leptin has a positive effect on promoting fracture healing during the latter stages in a clinically-relevant mouse bone fracture model, and increase callus VEGF levels.
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Affiliation(s)
- Zhisheng Wu
- Department of Orthopedics, The First Affiliated Hospital with Nanjing Medical University, Nanjing, China
| | - Peng Shao
- Department of Orthopedics, The First Affiliated Hospital with Nanjing Medical University, Nanjing, China; Department of General Surgery, Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, Nanjing Medical University Affiliated Cancer Hospital, Nanjing, China
| | - Crispin R Dass
- School of Pharmacy, Curtin University, Bentley, Australia
| | - Yongzhong Wei
- Department of Orthopedics, The First Affiliated Hospital with Nanjing Medical University, Nanjing, China.
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Erbasan F, Alikanoğlu AS, Yazısız V, Karasu U, Balkarlı A, Sezer C, Terzioğlu ME. Leptin and leptin receptors in salivary glands of primary Sjögren’s syndrome. Pathol Res Pract 2016; 212:1010-1014. [DOI: 10.1016/j.prp.2016.08.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 08/17/2016] [Accepted: 08/29/2016] [Indexed: 02/07/2023]
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Liu K, Liu P, Liu R, Wu X, Cai M. Relationship between serum leptin levels and bone mineral density: a systematic review and meta-analysis. Clin Chim Acta 2015; 444:260-3. [PMID: 25748037 DOI: 10.1016/j.cca.2015.02.040] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 02/22/2015] [Accepted: 02/23/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND The association between leptin and bone mineral density (BMD) is controversial because of conflicting findings from previous studies. METHODS This meta-analysis aimed to provide an overview of the serum leptin levels and BMD in a healthy population. We reviewed the PubMed, Embase, and Cochrane Library databases until July 2014 for research on the association between leptin levels and BMD in healthy people. RESULTS We included and analyzed 45 studies in this systematic review and meta-analysis. The pooled correlations between leptin and BMD were analyzed by using the method of the inverse of the variance. Leptin was positively associated with BMD and the bone mineral content (BMC), especially in postmenopausal women (pooled r: 0.13-0.49). Overall, high serum leptin levels were associated with higher BMD levels. CONCLUSIONS This meta-analysis suggests that serum leptin levels are positively associated with BMD and BMC, especially in postmenopausal women.
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Affiliation(s)
- Kuan Liu
- Department of Orthopedics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Pengcheng Liu
- Department of Orthopedics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Run Liu
- Department of Orthopedics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xing Wu
- Department of Orthopedics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.
| | - Ming Cai
- Department of Orthopedics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.
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Nejati-Koshki K, Akbarzadeh A, Pourhasan-Moghaddam M, Abhari A, Dariushnejad H. Inhibition of leptin and leptin receptor gene expression by silibinin-curcumin combination. Asian Pac J Cancer Prev 2015; 14:6595-9. [PMID: 24377502 DOI: 10.7314/apjcp.2013.14.11.6595] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Leptin and its receptor are involved in breast carcinogenesis as mitogenic factors. Therefore, they could be considered as targets for breast cancer therapy. Expression of the leptin receptor gene could be modulated by leptin secretion. Silibinin and curcumin are herbal compounds with anti-cancer activity against breast cancer. The aim of this study was to assess their potential to inhibit of expression of the leptin gene and its receptor and leptin secretion. Cytotoxic effects of the two agents on combination on T47D breast cancer cells was investigated by MTT assay test after 24h treatment. With different concentrations the levels of leptin, leptin receptor genes expression were measured by reverse-transcription real-time PCR. Amount of secreted leptin in the culture medium was determined by ELISA. Data were statistically analyzed by one-way ANOVA test. The silibinin and curcumin combination inhibited growth of T47D cells in a dose dependent manner. There were also significant difference between control and treated cells in leptin expression and the quantity of secreted leptin with a relative decrease in leptin receptor expression. In conclusion, these herbal compounds inhibit the expression and secretion of leptin and it could probably be used as drug candidates for breast cancer therapy through leptin targeting in the future.
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Affiliation(s)
- Kazem Nejati-Koshki
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran E-mail : ,
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Polyzos SA, Mantzoros CS. Leptin in health and disease: facts and expectations at its twentieth anniversary. Metabolism 2015; 64:5-12. [PMID: 25467841 DOI: 10.1016/j.metabol.2014.10.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 10/20/2014] [Accepted: 10/20/2014] [Indexed: 02/07/2023]
Affiliation(s)
- Stergios A Polyzos
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Christos S Mantzoros
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Boston VA Healthcare system and Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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Nejati-Koshki K, Akbarzadeh A, Pourhassan-Moghaddam M. Curcumin inhibits leptin gene expression and secretion in breast cancer cells by estrogen receptors. Cancer Cell Int 2014; 14:66. [PMID: 25866478 PMCID: PMC4392783 DOI: 10.1186/1475-2867-14-66] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 04/28/2014] [Indexed: 01/09/2023] Open
Abstract
Background Recent studies suggested that leptin as a mitogenic factor might play an important role in the process of initiation and progression of human cancer. Therefore, it could be considered as a target for breast cancer therapy. A previous study has showed that expression of leptin gene could be modulated by activation of estrogen receptors. Curcumin is a diferuloylmethane that has been shown to interfere with multiple cell signaling pathways and extensive research over the last 50 years has indicated this polyphenol can both prevent and treat cancer. Based on the fact that targeting of leptin could be considered as a novel strategy for breast cancer therapy, the aim of this study is the investigation of potentiality of curcumin for inhibition of leptin gene expression and secretion, and also, its link with expression of estrogen receptors. Methods Cytotoxic effect of curcumin on T47D breast cancer cells was investigated by MTT assay test after 24 and 48 treatments. Thereafter, the cells treated with different concentrations of curcumin. The levels of leptin, estrogen receptor α and estrogen receptor β genes expression was measured in the treated and control cells by Reverse-transcription real-time PCR. Amount of secreted leptin in the culture medium was also determined by ELISA in both treated and untreated cells. Finally data were statistically analyzed by one-way ANOVA test. Results Analysis of MTT assay data showed that curcumin inhibits growth of T47D cells with dose dependent manner. There were also significant difference between control and treated cells in the levels of leptin, estrogen receptor α expression levels and the quantity of secreted leptin that both were decreased in the treated cells compared with control cells. Conclusion Based on the results, curcumin inhibits the expression and secretion of leptin and it could probably be used as a drug candidate for the breast cancer therapy through the leptin targeting in the future.
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Affiliation(s)
- Kazem Nejati-Koshki
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Abolfazl Akbarzadeh
- Department of Medical Nanotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Pourhassan-Moghaddam
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran ; Department of Clinical Biochemistry, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
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Scotece M, Conde J, Abella V, López V, Pino J, Lago F, Gómez-Reino JJ, Gualillo O. Bone metabolism and adipokines: are there perspectives for bone diseases drug discovery? Expert Opin Drug Discov 2014; 9:945-57. [PMID: 24857197 DOI: 10.1517/17460441.2014.922539] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Over the past 20 years, the idea that white adipose tissue (WAT) is simply an energy depot organ has been radically changed. Indeed, present understanding suggests WAT to be an endocrine organ capable of producing and secreting a wide variety of proteins termed adipokines. These adipokines appear to be relevant factors involved in a number of different functions, including metabolism, immune response, inflammation and bone metabolism. AREAS COVERED In this review, the authors focus on the effects of several adipose tissue-derived factors in bone pathophysiology. They also consider how the modification of the adipokine network could potentially lead to promising treatment options for bone diseases. EXPERT OPINION There are currently substantial developments being made in the understanding of the interplay between bone metabolism and the metabolic system. These insights could potentially lead to the development of new treatment strategies and interventions with the aim of successful outcomes in many people affected by bone disorders. Specifically, future research should look into the intimate mechanisms regulating peripheral and central activity of adipokines as it has potential for novel drug discovery.
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Affiliation(s)
- Morena Scotece
- Santiago University Clinical Hospital, SERGAS, Division of Rheumatology, Research Laboratory 9 , Santiago de Compostela, 15706 , Spain
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Scotece M, Conde J, Vuolteenaho K, Koskinen A, López V, Gómez-reino J, Lago F, Moilanen E, Gualillo O. 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] [What about the content of this article? (0)] [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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Vuolteenaho K, Koskinen A, Moilanen E. Leptin - A Link between Obesity and Osteoarthritis. Applications for Prevention and Treatment. Basic Clin Pharmacol Toxicol 2013; 114:103-8. [DOI: 10.1111/bcpt.12160] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 10/14/2013] [Indexed: 01/24/2023]
Affiliation(s)
- Katriina Vuolteenaho
- The Immunopharmacology Research Group; University of Tampere School of Medicine and Tampere University Hospital; Tampere Finland
| | - Anna Koskinen
- The Immunopharmacology Research Group; University of Tampere School of Medicine and Tampere University Hospital; Tampere Finland
| | - Eeva Moilanen
- The Immunopharmacology Research Group; University of Tampere School of Medicine and Tampere University Hospital; Tampere Finland
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Khan SN, DuRaine G, Virk SS, Fung J, Rowland DJ, Reddi AH, Lee MA. The temporal role of leptin within fracture healing and the effect of local application of recombinant leptin on fracture healing. J Orthop Trauma 2013; 27:656-62. [PMID: 23287761 DOI: 10.1097/BOT.0b013e3182847968] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE We hypothesized that leptin is expressed in a specific time sequence during fracture healing, and its deficiency leads to impaired healing. METHODS Control (C57BL/6) mice and leptin -/- obese (ob/ob) mice were used. ARM 1:: Fracture callus was harvested at 1, 3, 5, 7, 10, 14, and 21 days (n = 8/time point) after closed middiaphyseal femur fractures were created in 56 C57BL/6 mice, and reverse transcriptase polymerase chain reaction analysis was then performed. Levels of leptin were tracked at each time point listed. ARM 2:: Forty-two C57BL/6 controls and 42 ob/ob mice underwent open stabilized middiaphyseal femur fractures, and tissues were harvested at 14, 21, and 42 days and radiographic, histologic, and quantitative computerized tomography analyses were performed. ARM 3:: Murine recombinant leptin was applied directly at the newly created fracture site in 2 separate groups (10 or 100 μg of leptin) of 42 ob/ob mice. Two-factor analysis of variance and the Student t-test were used for statistical analysis. RESULTS The time course of Leptin mRNA expression within a fracture callus was detected. Delay in callus maturation was demonstrated radiographically and histologically in the ob/ob mice. ob/ob fractures had an increase in total callus volume by quantitative computerized tomography (P < 0.05). Application of local leptin at both doses reversed the delay in healing. CONCLUSIONS Leptin is expressed in a unique time course during fracture healing and leptin deficiency leads to impaired fracture healing that reverses by local application of leptin.
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Pacifico L, Bezzi M, Lombardo CV, Romaggioli S, Ferraro F, Bascetta S, Chiesa C. Adipokines and C-reactive protein in relation to bone mineralization in pediatric nonalcoholic fatty liver disease. World J Gastroenterol 2013; 19:4007-4014. [PMID: 23840146 PMCID: PMC3703188 DOI: 10.3748/wjg.v19.i25.4007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 04/02/2013] [Accepted: 04/19/2013] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate bone mineral density (BMD) in obese children with and without nonalcoholic fatty liver disease (NAFLD); and the association between BMD and serum adipokines, and high-sensitivity C-reactive protein (HSCRP).
METHODS: A case-control study was performed. Cases were 44 obese children with NAFLD. The diagnosis of NAFLD was based on magnetic resonance imaging (MRI) with high hepatic fat fraction (≥ 5%). Other causes of chronic liver disease were ruled out. Controls were selected from obese children with normal levels of aminotransferases, and without MRI evidence of fatty liver as well as of other causes of chronic liver diseases. Controls were matched (1- to 1-basis) with the cases on age, gender, pubertal stage and as closely as possible on body mass index-SD score. All participants underwent clinical examination, laboratory tests, and whole body (WB) and lumbar spine (LS) BMD by dual energy X-ray absorptiometry. BMD Z-scores were calculated using race and gender specific LMS curves.
RESULTS: Obese children with NAFLD had a significantly lower LS BMD Z-score than those without NAFLD [mean, 0.55 (95%CI: 0.23-0.86) vs 1.29 (95%CI: 0.95-1.63); P < 0.01]. WB BMD Z-score was also decreased in obese children with NAFLD compared to obese children with no NAFLD, though borderline significance was observed [1.55 (95%CI: 1.23-1.87) vs 1.95 (95%CI: 1.67-2.10); P = 0.06]. Children with NAFLD had significantly higher HSCRP, lower adiponectin, but similar leptin levels. Thirty five of the 44 children with MRI-diagnosed NAFLD underwent liver biopsy. Among the children with biopsy-proven NAFLD, 20 (57%) had nonalcoholic steatohepatitis (NASH), while 15 (43%) no NASH. Compared to children without NASH, those with NASH had a significantly lower LS BMD Z-score [mean, 0.27 (95%CI: -0.17-0.71) vs 0.75 (95%CI: 0.13-1.39); P < 0.05] as well as a significantly lower WB BMD Z-score [1.38 (95%CI: 0.89-1.17) vs 1.93 (95%CI: 1.32-2.36); P < 0.05]. In multiple regression analysis, NASH (standardized β coefficient, -0.272; P < 0.01) and HSCRP (standardized β coefficient, -0.192; P < 0.05) were significantly and independently associated with LS BMD Z-score. Similar results were obtained when NAFLD (instead of NASH) was included in the model. WB BMD Z-scores were significantly and independently associated with NASH (standardized β coefficient, -0.248; P < 0.05) and fat mass (standardized β coefficient, -0.224; P < 0.05).
CONCLUSION: This study reveals that NAFLD is associated with low BMD in obese children, and that systemic, low-grade inflammation may accelerate loss of bone mass in patients with NAFLD.
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Nejati-Koshki K, Zarghami N, Pourhassan-Moghaddam M, Rahmati-Yamchi M, Mollazade M, Nasiri M, Esfahlan RJ, Barkhordari A, Tayefi-Nasrabadi H. Inhibition of leptin gene expression and secretion by silibinin: possible role of estrogen receptors. Cytotechnology 2012; 64:719-26. [PMID: 22526491 DOI: 10.1007/s10616-012-9452-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Accepted: 03/31/2012] [Indexed: 02/06/2023] Open
Abstract
Leptin plays the role of mitogenic factor in the breast carcinogenesis. Therefore, it could be considered as a target for breast cancer therapy. Leptin gene expression could be modulated by activation of estrogen receptors. Silibinin is an herbal compound with anti-cancer activity on prostate and colorectal cancers. Based on the fact that targeting of leptin can be considered as a novel strategy for breast cancer therapy, the aim of this study was the investigation of potentiality of silibinin for inhibition of leptin gene expression and secretion, and its link with expression of estrogen receptors. Cytotoxic effect of silibinin on T47D breast cancer cells was investigated by MTT assay test after 24, 48 and 72 h treatments with different concentrations of silibinin. The levels of leptin, estrogen receptor α and estrogen receptor β genes expression was measured by reverse-transcription real-time PCR. The amount of secreted leptin in the culture medium was determined by ELISA. Data were statistically analyzed by one-way ANOVA test. Silibinin inhibits growth of T47D cells in a time and dose dependent manner. There was significant difference between control and treated cells in the levels of leptin, estrogen receptor β expression levels and the quantity of secreted leptin was decreased in the treated cells in comparison to control cells. In conclusion, silibinin inhibits the expression and the secretion of leptin and in the future it might probably be a drug candidate for breast cancer therapy through leptin targeting.
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Affiliation(s)
- Kazem Nejati-Koshki
- Tuberculosis and Lung Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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Vitali A, Murano I, Zingaretti MC, Frontini A, Ricquier D, Cinti S. The adipose organ of obesity-prone C57BL/6J mice is composed of mixed white and brown adipocytes. J Lipid Res 2012; 53:619-29. [PMID: 22271685 DOI: 10.1194/jlr.m018846] [Citation(s) in RCA: 340] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
White and brown adipocytes are believed to occupy different sites in the body. We studied the anatomical features and quantitative histology of the fat depots in obesity and type 2 diabetes-prone C57BL/6J mice acclimated to warm or cold temperatures. Most of the fat tissue was contained in depots with discrete anatomical features, and most depots contained both white and brown adipocytes. Quantitative analysis showed that cold acclimation induced an increase in brown adipocytes and an almost equal reduction in white adipocytes; however, there were no significant differences in total adipocyte count or any signs of apoptosis or mitosis, in line with the hypothesis of the direct transformation of white into brown adipocytes. The brown adipocyte increase was accompanied by enhanced density of noradrenergic parenchymal nerve fibers, with a significant correlation between the density of these fibers and the number of brown adipocytes. Comparison with data from obesity-resistant Sv129 mice disclosed a significantly different brown adipocyte content in C57BL/6J mice, suggesting that this feature could underpin the propensity of the latter strain to develop obesity. However, the greater C57BL/6J browning capacity can hopefully be harnessed to curb obesity and type 2 diabetes in patients with constitutively low amounts of brown adipose tissue.
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Affiliation(s)
- A Vitali
- Department of Experimental and Clinical Medicine, University of Ancona, (Politecnica delle Marche), 60020 Ancona, Italy
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Williams GA, Callon KE, Watson M, Costa JL, Ding Y, Dickinson M, Wang Y, Naot D, Reid IR, Cornish J. Skeletal phenotype of the leptin receptor-deficient db/db mouse. J Bone Miner Res 2011; 26:1698-709. [PMID: 21328476 DOI: 10.1002/jbmr.367] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Leptin, a major hormonal product of the adipocyte, regulates appetite and reproductive function through its hypothalamic receptors. The leptin receptor is present in osteoblasts and chondrocytes, and previously we have shown leptin to be an anabolic bone factor in vitro, stimulating osteoblast proliferation and inhibiting osteoclastogenesis. Leptin increases bone mass and reduces bone fragility when administered peripherally but also can indirectly reduce bone mass when administered into the central nervous system. However, data from animal models deficient in either leptin (ob/ob) or its receptor (db/db) remain contradictory. We compared the bone phenotype of leptin receptor-deficient (db/db) and wild-type mice using micro-computed tomographic (µCT) analysis of the proximal tibias and vertebrae. In the tibia, db/db mice had reduced percent trabecular bone volume (13.0 ± 1.62% in wild-type versus 6.01 ± 0.601% in db/db mice, p = .002) and cortical bone volume (411 ± 21.5 µm(3) versus 316 ± 3.53 µm(3), p = .0014), trabecular thickness (48.4 ± 001.07 µm versus 45.1 ± 0.929 µm, p = .041) and trabecular number (2.68 ± 0.319 mm(-1) versus 1.34 ± 0.148 mm(-1), p = .0034). In the fifth lumbar vertebral body, the trabecular thickness and cortical thickness were decreased in the db/db versus wild-type mice (0.053 ± 0.0011 mm versus 0.047 ± 0.0013 mm, p = .0002 and 0.062 ± 0.00054 mm versus 0.056 ± 0.0009 mm, p = .0001), respectively, whereas the trabecular and cortical percent bone volume and trabecular number did not reach significance. The total (endosteal and periosteal) cortical perimeter (12.2 ± 0.19 mm versus 13.2 ± 0.30 mm, p = .01) was increased. The serum osteocalcin levels were reduced in the db/db mice, suggesting that bone formation rates are decreased. The material properties of db/db femurs were determined by three-point bending and nanoindentation, showing decreased bone strength (13.3 ± 0.280 N versus 7.99 ± 0.984 N, p = .0074) and material stiffness (28.5 ± 0.280 GPa versus 25.8 ± 0.281 GPa, p < .0001). These results demonstrate that bone mass and strength are reduced in the absence of leptin signaling, indicating that leptin acts in vivo as an anabolic bone factor. This concurs with results of in vitro studies and of peripheral leptin administration in vivo and suggests that leptin's direct effects on bone cells are likely to override its actions via the central nervous system.
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Affiliation(s)
- Garry A Williams
- Department of Medicine, University of Auckland, Auckland, New Zealand.
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Ohba S, Lanigan TM, Roessler BJ. Leptin receptor JAK2/STAT3 signaling modulates expression of Frizzled receptors in articular chondrocytes. Osteoarthritis Cartilage 2010; 18:1620-9. [PMID: 20868760 PMCID: PMC2997121 DOI: 10.1016/j.joca.2010.09.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 09/13/2010] [Accepted: 09/14/2010] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Differentiated articular chondrocytes express a functional bisoform of the leptin receptor (LRb); however, leptin-LRb signaling in these cells is poorly understood. We hypothesized that leptin-LRb signaling in articular chondrocytes functions to modulate canonical Wnt signaling events by altering the expression of Frizzled (FZD) receptors. METHODS Human chondrocyte cell lines and primary articular chondrocytes were grown in serum containing growth media for 24h, followed by a media change to Dulbecco's modified Eagle's medium (DMEM) containing 1% Nutridoma-SP to obtain a serum-deficient environment for 24h before treatment. Treatments included recombinant human leptin (10-100nM), recombinant human IL-6 (0.3-3nM), or recombinant human erythropoietin (Epo) (10mU/ml). Cells were harvested 30min-48h after treatment and whole cell lysates were analyzed using immunoblots or luciferase assays. RESULTS Treatment of cells with leptin resulted in activation of Janus kinase 2 (JAK2) and subsequent phosphorylation of specific tyrosine residues on LRb, followed by dose- and time-dependent increases in the expression of Frizzled-1 (FZD1) and Frizzled-7 (FZD7). Leptin-mediated increases in the expression of FZD1 were blocked by pre-treatment with the protein synthesis inhibitor cycloheximide or the JAK2 inhibitor AG490. Experiments using a series of hybrid Epo extracellular domain-leptin intracellular domain receptors (ELR) harboring mutations of specific tyrosine residues in the cytoplasmic tail showed that increases in the expression of FZD1 were dependent on LRb-mediated phosphorylation of STAT3, but not ERK1/2 or STAT5. Leptin pre-treatment of chondrocytes prior to Wnt3a stimulation resulted in an increased magnitude of canonical Wnt signaling. CONCLUSION These experiments show that leptin-LRb signaling in articular chondrocytes modulates expression of canonical Wnt signaling receptors and suggests that direct cross-talk between these pathways is important in determining chondrocyte homeostasis.
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Affiliation(s)
- Seigo Ohba
- Division of Rheumatology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109-5688
| | - Thomas M. Lanigan
- Division of Rheumatology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109-5688
| | - Blake J. Roessler
- Division of Rheumatology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109-5688
- To whom correspondence should be addressed: 3560 MSRB2, 1150 W. Medical Center Dr., Ann Arbor, MI 48109-5688, Tel.: 734-763-7949, Fax: 734-764-3596,
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Stannus OP, Jones G, Quinn SJ, Cicuttini FM, Dore D, Ding C. The association between leptin, interleukin-6, and hip radiographic osteoarthritis in older people: a cross-sectional study. Arthritis Res Ther 2010; 12:R95. [PMID: 20482813 PMCID: PMC2911879 DOI: 10.1186/ar3022] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 12/12/2010] [Accepted: 05/19/2010] [Indexed: 12/15/2022] Open
Abstract
Introduction The associations between leptin, interleukin (IL)-6, and hip radiographic osteoarthritis (OA) have not been reported, and their roles in obesity-related hip OA are unclear. The aim of this study was to describe the associations between leptin, IL-6, and hip radiographic osteoarthritis (ROA) in older adults. Methods A cross-sectional sample of 193 randomly selected subjects (mean age, 63 years; range, 52 to 78 years; 48% female subjects) were studied. Hip ROA, including joint-space narrowing (JSN) and osteophytes, was determined by anteroposterior radiograph. Serum levels of leptin and interleukin (IL)-6 were measured with radioimmunoassay. Fat mass was measured with dual-energy x-ray absorptiometry (DXA). Body mass index (BMI) and waist-to-hip ratio (WHR) were calculated. Results In multivariable analysis, hip JSN was associated with serum levels of leptin in the whole sample (β = 0.046 per μg/L, P = 0.024 for superior; β = 0.068 per μg/L, P = 0.004 for axial compartment) and IL-6 only in females (β = 0.241 per pg/ml, P = 0.002 for superior; β = 0.239 per pg/ml, P = 0.001 for axial compartment). The positive associations between body-composition measures (BMI, WHR, percentage total fat mass, and percentage trunk fat mass) and hip JSN in women became nonsignificant after adjustment for leptin but not for IL-6. No significant associations were found between leptin, IL-6, and the presence or severity of osteophytes. Conclusions This study suggests that metabolic and inflammatory mechanisms may play a role in the etiology of hip OA and that the associations between body composition and hip JSN are mediated by leptin, particularly in women.
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Affiliation(s)
- Oliver P Stannus
- Menzies Research Institute, University of Tasmania, Private Bag 23, Hobart, Tasmania 7000, Australia
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Abstract
Osteoarthritis (OA) is a most common multifactorial degenerative joint disease in elderly individuals. OA is affecting severely the quality of life of patients, while the causes of OA are not completely understood. Age, obesity, the female sex, and previous injury are considered as significant risk factors. Recently, increased levels of adipokines which are mainly produced by adipocytes have been detected in patients with osteoarthritis. Moreover, studies on different adipokines all reveal that they have played proinflammatory and catabolic/anabolic roles during the pathophysiology of OA. In the present review, we summarize current data on the effect of the adipose tissue-derived hormones leptin, adiponectin, resistin and visfatin on initiation and progression of OA.
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Affiliation(s)
- Peng-fei Hu
- Zhejiang University College of Medicine, Hangzhou, People's Republic of China
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Bertoni L, Ferretti M, Cavani F, Zavatti M, Resca E, Benelli A, Palumbo C. Leptin increases growth of primary ossification centers in fetal mice. J Anat 2009; 215:577-83. [DOI: 10.1111/j.1469-7580.2009.01134.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Zhao CQ, Liu D, Li H, Jiang LS, Dai LY. Expression of leptin and its functional receptor on disc cells: contribution to cell proliferation. Spine (Phila Pa 1976) 2008; 33:E858-64. [PMID: 18978578 DOI: 10.1097/BRS.0b013e31818338e5] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Human herniated disc tissues and rat nucleus pulposus (NP) cells were used following approval by the authors' institutional Human Ethics Review Committee and Animal Care and Use Committee. OBJECTIVE To determine the expression of leptin and its functional receptor in herniated disc tissues, and to elucidate whether leptin can stimulate rat NP cells to proliferate in vitro. SUMMARY OF BACKGROUND DATA There is evidence showing that chondrocytes express leptin and functional leptin receptor, and leptin stimulates chondrocyte proliferation in vitro and may play a role in the pathogenesis of osteoarthritis by contributing to osteophyte formation. Intervertebral disc degeneration, similar to osteoarthritis, is also a complicated process in which increased cell proliferation is involved. However, little attention has been paid to the causes of the increased cell proliferation during disc degeneration. METHODS Forty-five herniated discs were harvested and immunostained to determine the distribution and type of leptin/functional leptin receptor-expressing cells. The proliferating activity of rat NP cells stimulated with leptin was also evaluated by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and by immunostaining for proliferation cell nuclear antigen (PCNA). RESULTS Immunohistochemical results from 45 herniated discs showed that leptin/functional leptin receptor-positive cells are commonly seen in cell clusters and proliferating fibrocartilaginous areas, and that the percentage of leptin/functional leptin receptor-positive cells correlates with the age of the patients. Leptin administration led to increased proliferation of rat NP cells in a dose-dependent manner, as shown by MTT assay and by counting the percentage of PCNA-positive cells. CONCLUSION Our results suggested that disc cells can express leptin and its functional receptor, that leptin can stimulate proliferation of disc cells in vitro, and therefore that leptin may play a role in the process of intervertebral disc degeneration by contributing to the formation of cell cluster and proliferating fibrocartilaginous tissue.
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Abstract
Leptin and its actions in bone came to prominence in 2000, with the publication of two landmark articles identifying a novel interaction between energy and bone homeostasis, as well as a novel hypothalamic circuit to the skeleton. However, they also revealed the dichotomous nature of leptin's effect on the skeleton. Subsequent research has increased understanding of the factors critical to interpretation of the leptin-bone signaling. These include opposing effects in cortical and cancellous bone, central and peripheral effects, involvement of other neural and endocrine factors, and leptin receptor polymorphisms in human populations. It is clear that leptin can markedly influence the regulation of bone mass, and that study of this pathway continues to increase our knowledge of the biology of skeletal tissue and its interactions with other tissues. However, this relationship is complex and requires careful interpretation.
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Affiliation(s)
- Nicola J Lee
- Neuroscience Research Program, Garvan Institute of Medical Research, St. Vincent's Hospital, 384 Victoria Street, Darlinghurst, Sydney, NSW 2010, Australia
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Abstract
The past few years of research on leptin have provided important information on the link between metabolism and immune homeostasis. Adipocytes influence not only the endocrine system but also the immune response through several cytokine-like mediators known as adipokines, which include leptin. It is widely accepted that leptin can directly link nutritional status and pro-inflammatory T helper 1 immune responses, and that a decrease of leptin plasma concentration during food deprivation can lead to an impaired immune function. Additionally, several studies have implicated leptin in the pathogenesis of chronic inflammation, and the elevated circulating leptin levels in obesity appear to contribute to the low-grade inflammatory background which makes obese individuals more susceptible to increased risk of developing cardiovascular diseases, type II diabetes, or degenerative disease including autoimmunity and cancer. Conversely, reduced levels of leptin such as those found in malnourished individuals have been linked to increased risk of infection and reduced cell-mediated immune responses. We discuss here the functional influences of leptin in the physiopathology of inflammation, and the effects of leptin in the modulation of such responses.
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Affiliation(s)
- Noriko Iikuni
- Department of Medicine, University of California Los Angeles, USA
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Abstract
Body weight impacts both bone turnover and bone density, making it, therefore, an important risk factor for vertebral and hip fractures and ranking it alongside age in importance. The effect of body weight is probably contributed to by both fat mass and lean mass, though in postmenopausal women, fat mass has been more consistently demonstrated to be important. A number of mechanisms for the fat-bone relationship exist and include the effect of soft tissue mass on skeletal loading, the association of fat mass with the secretion of bone active hormones from the pancreatic beta cell (including insulin, amylin, and preptin), and the secretion of bone active hormones (e.g., estrogens and leptin) from the adipocyte. These factors alone probably do not fully explain the observed clinical associations, and study of the actions on bone of novel hormones related to nutrition is an important area of further research. An understanding of this aspect of bone biology may open the way for new treatments of osteoporosis. More immediately, the role of weight maintenance in the prevention of osteoporosis is an important public health message that needs to be more widely appreciated.
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Affiliation(s)
- I R Reid
- University of Auckland, Auckland, New Zealand.
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Gruber HE, Ingram JA, Hoelscher GL, Hanley EN. Leptin expression by annulus cells in the human intervertebral disc. Spine J 2007; 7:437-43. [PMID: 17433782 DOI: 10.1016/j.spinee.2006.08.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2006] [Revised: 08/11/2006] [Accepted: 08/21/2006] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT It is now known that leptin acts not only as a metabolic signal related to energy homeostasis but also as an endocrine hormone regulating traditional endocrine systems and neuroendocrine function in various cells. It participates in bone remodeling and acts as a growth factor stimulating proliferation. Expression of leptin and the presence of leptin receptors have not been explored in disc tissue. PURPOSE To determine (1) whether leptin is produced by cells in the human annulus in vivo, (2) whether annulus cells have leptin receptors in vivo and in vitro, and (3) whether measurable amounts of leptin are produced during three-dimensional culture of human annulus cells. STUDY DESIGN/SETTING Studies were approved by the human subjects Institutional Review Board. Surgical and donor disc tissue was obtained and assessed by using immunocytochemistry of paraffin-embedded disc tissue. Annulus cells were also cultured from disc specimens and conditioned media assessed for the production of leptin during three-dimensional culture. PATIENT SAMPLE Disc tissue was examined from 7 young subjects and 29 adult subjects. OUTCOME MEASURES Immunodetection of leptin and leptin receptors in cells of the human annulus; conditioned media was analyzed for production of leptin in vitro by human disc cells. METHODS Human annulus tissue and cultured cells were examined by using immunohistochemical methods to identify the presence of leptin and leptin receptors. Human disc cells were assayed for leptin production in three-dimensional culture. RESULTS Immunocytochemistry showed the presence of intracellular leptin and the presence of leptin receptors in some (but not all) annulus cells in the human disc. Production of leptin by annulus cells was further confirmed by assays of conditioned media from three-dimensional annulus cell culture. CONCLUSIONS These novel studies identify the presence of a heretofore unrecognized cytokine/hormone and its receptor in human annulus cells. Because of the mitogenic role of leptin in other tissues, the present work points to the importance of future studies to explore whether leptin has a mitogenic function in maintaining disc cell numbers.
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Affiliation(s)
- Helen E Gruber
- Department of Orthopaedic Surgery, Carolinas Medical Center, Charlotte, NC 28232, USA.
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Abstract
Reviews on the inflammatory role of adipose tissue outside the field of metabolism are rare. There is increasing evidence provided by numerous basic research studies from nearly all internal medicine subspecializations that adipocytes and adipocytokines are involved in primary inflammatory processes and diseases. Therefore, it is the aim of the present review to discuss and to summarize the current knowledge on the inflammatory role of adipocytokines and special types of regional adipocytes such as retroorbital, synovial, visceral, subdermal, peritoneal, and bone marrow adipocytes in internal medicine diseases. Future clinical and therapeutic implications are discussed.
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Affiliation(s)
- A Schäffler
- Department of Internal Medicine I, University of Regensburg, Germany.
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Affiliation(s)
- Ian R Reid
- Department of Medicine, University of Auckland, Auckland, New Zealand.
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Abstract
Leptin influences satiety, adiposity, and metabolism and is associated with mechanisms regulating puberty onset, fertility, and pregnancy in various species. Maternal hyperleptinemia is a hallmark of mammalian pregnancy, although both the roles of leptin and the mechanisms regulating its synthesis appear to be taxa specific. In pregnant humans and nonhuman primates, leptin is produced by both maternal and fetal adipose tissues, as well as by the placental trophoblast. Specific receptors in the uterine endometrium, trophoblast, and fetus facilitate direct effects of the polypeptide on implantation, placental endocrine function, and conceptus development. A soluble isoform of the receptor may be responsible for inducing maternal leptin resistance during pregnancy and/or may facilitate the transplacental passage of leptin for the purpose of directly regulating fetal development. The steroid hormones are linked to the regulation of leptin and the leptin receptor and probably interact with other pregnancy-specific, serum-borne factors to regulate leptin dynamics during pregnancy. In addition to its effects on normal conceptus development, leptin is linked to mechanisms affecting a diverse array of pregnancy-specific pathologies that include preeclampsia, gestational diabetes, and intrauterine growth restriction. Association with these anomalies and with mechanisms pointing to a fetal origin for a range of conditions affecting the individual's health in adult life, such as obesity, diabetes mellitus, and cardiovascular disease, reiterate the need for continued research dedicated to elucidating leptin's roles and regulation throughout gestation.
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Affiliation(s)
- Michael C Henson
- Department of Obstetrics and Gynecology, Tulane University Health Sciences Center, New Orleans, Louisiana 70112-2699, USA.
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Abstract
Adipocytes anatomically associated with lymph nodes (and omental milky spots) have many special properties including fatty acid composition and the control of lipolysis that equip them to interact locally with lymphoid cells. Lymph node lymphocytes and tissue dendritic cells acquire their fatty acids from the contiguous adipocytes. Lymph node-derived dendritic cells suppress lipolysis in perinodal adipocytes but those that permeate the adipose tissue stimulate lipolysis, especially after minor, local immune stimulation. Inflammation alters the composition of fatty acids incorporated into dendritic cells, and that of node-containing adipose tissue, counteracting the effects of dietary lipids. Thus these specialised adipocytes partially emancipate the immune system from fluctuations in the abundance and composition of dietary lipids. Prolonged, low-level immune stimulation induces the local formation of more adipocytes, especially adjacent to the inflamed lymph node. This mechanism may contribute to hypertrophy of the mesentery and omentum in chronic inflammatory diseases such as HIV-infection, and in smokers. Paracrine interactions between adipose and lymphoid tissues are enhanced by diets rich in n-6 fatty acids and attentuated by fish oils. The latter improve immune function and body conformation in animals and people. The partitioning of adipose tissue in many depots, some specialised for local, paracrine interactions with other tissues, is a fundamental feature of mammals.
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Affiliation(s)
- Caroline M Pond
- Department of Biological Sciences, The Open University, Milton Keynes MK7 6AA, UK.
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