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Han Y, Wu J, Ji R, Tan H, Tian S, Yin J, Xu J, Chen X, Liu W, Cui H. Preoperative sarcopenia combined with prognostic nutritional index predicts long-term prognosis of radical gastrectomy with advanced gastric cancer: a comprehensive analysis of two-center study. BMC Cancer 2023; 23:751. [PMID: 37580693 PMCID: PMC10424379 DOI: 10.1186/s12885-023-11251-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 08/03/2023] [Indexed: 08/16/2023] Open
Abstract
PURPOSE This study aims to investigate the predictive value of the combined index smni(skeletal muscle index (SMI)-prognostic nutrition index(PNI)) for the postoperative survival of patients with advanced gastric cancer(AGC). METHODS 650 patients with AGC from two centers (290 cases from the First Affiliated Hospital of Dalian University and 360 points from the Fujian Medical University Union Hospital) were selected as the study subjects based on unified screening criteria. Clinical data, preoperative abdominal CT images, results of hematology-related examinations, tumor-related characteristics, and surgical and follow-up data of the patients were collected and organized. The L3 vertebral level muscle area was measured using computer-assisted measurement techniques, and the skeletal muscle index(SMI) was calculated based on this measurement. The prognostic nutrition index (PNI) was calculated based on serum albumin and lymphocyte count indicators. The Kaplan-Meier survival analysis of data from the First Affiliated Hospital was used to determine that SMI and PNI are significantly correlated with the postoperative survival rate of patients with advanced gastric cancer. Based on this, a novel combined index smni was fitted and stratified for risk. Cox proportional hazards regression analysis was used to determine that the index smni is an independent prognostic risk factor for patients with AGC after surgery. The ROC curve was used to describe the predictive ability of the new combined index and its importance and predictive power in predicting postoperative survival of patients with AGC, which was verified in the data of Fujian Medical University Union Hospital. RESULT The Kaplan-Meier curve analysis of the combined indicator smni Is clearly associated with long-term survival(3-year OS (P < 0.001) and DSS (P < 0.001)), univariate analysis and multivariate analysis showed that smni was an independent prognostic risk factor, The ROC curve for the first center 3-year OS(AUC = 0.678), DSS(AUC = 0.662) show good predictive ability and were validated in the second center. CONCLUSION The combined index smni has a good predictive ability for the postoperative survival rate of patients with AGC and is expected to provide a new reference basis and more accurate and scientific guidance for the postoperative management and treatment of patients with AGC.
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Affiliation(s)
- Yubo Han
- Department of General Surgery, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Ju Wu
- Fujian Medical University Union Hospital, Department of Gastric Surgery, Fuzhou, China
| | - Rui Ji
- Department of General Surgery, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Hao Tan
- Department of General Surgery, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Simiao Tian
- Department of Medical Record and Statistics, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Jiajun Yin
- Department of General Surgery, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Jian Xu
- Department of General Surgery, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Xi Chen
- Department of General Surgery, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Wenfei Liu
- Department of Radiology, Affiliated Zhongshan Hospital of Dalian University, Dalian, China.
| | - Hongzhang Cui
- Department of General Surgery, Affiliated Zhongshan Hospital of Dalian University, Dalian, China.
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The Patient's Physiological Status at the Start Determines the Success of the Inpatient Cardiovascular Rehabilitation Program. J Clin Med 2023; 12:jcm12051735. [PMID: 36902521 PMCID: PMC10003145 DOI: 10.3390/jcm12051735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/11/2023] [Accepted: 02/13/2023] [Indexed: 02/24/2023] Open
Abstract
Multidisciplinary inpatient rehabilitation plays an important role in the recovery of patients with cardiovascular diseases (CVDs). Lifestyle changes, achieved by exercise, diet, weight loss and patient education programs, are the first steps to a healthier life. Advanced glycation end products (AGEs) and their receptor (RAGE) are known to be involved in CVDs. Clarification on whether initial AGE levels can influence the rehabilitation outcome is important. Serum samples were collected at the beginning and end of the inpatient rehabilitation stay and analyzed for parameters: lipid metabolism, glucose status, oxidative stress, inflammation and AGE/RAGE-axis. As result, a 5% increase in the soluble isoform RAGE (sRAGE) (T0: 891.82 ± 44.97 pg/mL, T1: 937.17 ± 43.29 pg/mL) accompanied by a 7% decrease in AGEs (T0: 10.93 ± 0.65 µg/mL, T1: 10.21 ± 0.61 µg/mL) was shown. Depending on the initial AGE level, a significant reduction of 12.2% of the AGE activity (quotient AGE/sRAGE) was observed. We found that almost all measured factors improved. Summarizing, CVD-specific multidisciplinary rehabilitation positively influences disease-associated parameters, and thus provides an optimal starting point for subsequent disease-modifying lifestyle changes. Considering our observations, the initial physiological situations of patients at the beginning of their rehabilitation stay seem to play a decisive role regarding the assessment of rehabilitation success.
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Ratajczyk K, Konieczny A, Czekaj A, Piotrów P, Fiutowski M, Krakowska K, Kowal P, Witkiewicz W, Marek-Bukowiec K. The Clinical Significance of Urinary Retinol-Binding Protein 4: A Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:9878. [PMID: 36011513 PMCID: PMC9408023 DOI: 10.3390/ijerph19169878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/07/2022] [Accepted: 08/08/2022] [Indexed: 06/15/2023]
Abstract
Effective biomarkers for early diagnosis, prognostication, and monitoring in renal diseases (in general) comprise an unmet need. Urinary retinol-binding protein 4, which is the most sensitive indicator of renal tubular damage, holds great promise as a universal biomarker for renal pathologies, in which tubular injury is the driving force. Here, we summarize the most important existing data on the associations between urinary retinol-binding protein 4 and renal diseases and highlight the untapped potential of retinol-binding protein 4 in clinical use.
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Affiliation(s)
- Krzysztof Ratajczyk
- Department of Urology, Regional Specialist Hospital in Wroclaw, Kamienskiego 73a, 51-124 Wroclaw, Poland
| | - Andrzej Konieczny
- Department of Nephrology and Transplantation Medicine, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw, Poland
| | - Adrian Czekaj
- Department of Urology, Regional Specialist Hospital in Wroclaw, Kamienskiego 73a, 51-124 Wroclaw, Poland
| | - Paweł Piotrów
- Department of Urology, Regional Specialist Hospital in Wroclaw, Kamienskiego 73a, 51-124 Wroclaw, Poland
| | - Marek Fiutowski
- Department of Urology, Regional Specialist Hospital in Wroclaw, Kamienskiego 73a, 51-124 Wroclaw, Poland
| | - Kornelia Krakowska
- Department of Nephrology and Transplantation Medicine, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw, Poland
| | - Paweł Kowal
- Department of Urology, Regional Specialist Hospital in Wroclaw, Kamienskiego 73a, 51-124 Wroclaw, Poland
| | - Wojciech Witkiewicz
- Research and Development Center, Regional Specialist Hospital in Wroclaw, Kamienskiego 73a, 51-124 Wroclaw, Poland
| | - Karolina Marek-Bukowiec
- Research and Development Center, Regional Specialist Hospital in Wroclaw, Kamienskiego 73a, 51-124 Wroclaw, Poland
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Abstract
Nonalcoholic fatty liver disease (NAFLD) is becoming increasingly common as the global economy grows and living standards improve. Timely and effective preventions and treatments for NAFLD are urgently needed. Retinol-binding protein-4 (RBP4), the protein that transports retinol through the circulation, was found to be positively related to diabetes, obesity, cardiovascular disease, and other metabolic diseases. Observational studies on the association between serum RBP4 level and the prevalence of NAFLD found contradictory results. Some of the underlying mechanisms responsible for this association have been revealed, and the possible clinical implications of treating NAFLD by targeting RBP4 have been demonstrated. Future studies should focus on the predictive value of RBP4 on NAFLD development and its potential as a therapeutic target in NAFLD.
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Deng Q, Chen J. Potential Therapeutic Effect of All-Trans Retinoic Acid on Atherosclerosis. Biomolecules 2022; 12:biom12070869. [PMID: 35883425 PMCID: PMC9312697 DOI: 10.3390/biom12070869] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 06/08/2022] [Accepted: 06/22/2022] [Indexed: 11/16/2022] Open
Abstract
Atherosclerosis is a major risk factor for myocardial infarction and ischemic stroke, which are the leading cause of death worldwide. All-trans retinoic acid (ATRA) is a natural derivative of essential vitamin A. Numerous studies have shown that ATRA plays an important role in cell proliferation, cell apoptosis, cell differentiation, and embryonic development. All-trans retinoic acid (ATRA) is a ligand of retinoic acid receptors that regulates various biological processes by activating retinoic acid signals. In this paper, the metabolic processes of ATRA were reviewed, with emphasis on the effects of ATRA on inflammatory cells involved in the process of atherosclerosis.
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Nono Nankam PA, Blüher M. Retinol-binding protein 4 in obesity and metabolic dysfunctions. Mol Cell Endocrinol 2021; 531:111312. [PMID: 33957191 DOI: 10.1016/j.mce.2021.111312] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/28/2021] [Accepted: 04/29/2021] [Indexed: 12/11/2022]
Abstract
Excessive increased adipose tissue mass in obesity is associated with numerous co-morbid disorders including increased risk of type 2 diabetes, fatty liver disease, hypertension, dyslipidemia, cardiovascular diseases, dementia, airway disease and some cancers. The causal mechanisms explaining these associations are not fully understood. Adipose tissue is an active endocrine organ that secretes many adipokines, cytokines and releases metabolites. These biomolecules referred to as adipocytokines play a significant role in the regulation of whole-body energy homeostasis and metabolism by influencing and altering target tissues function. Understanding the mechanisms of adipocytokine actions represents a hot topic in obesity research. Among several secreted bioactive signalling molecules from adipose tissue and liver, retinol-binding protein 4 (RBP4) has been associated with systemic insulin resistance, dyslipidemia, type 2 diabetes and other metabolic diseases. Here, we aim to review and discuss the current knowledge on RBP4 with a focus on its role in the pathogenesis of obesity comorbid diseases.
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Affiliation(s)
- Pamela A Nono Nankam
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Germany.
| | - Matthias Blüher
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Germany; Medical Department III - Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Germany
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Abstract
Much evidence has accumulated in the literature over the last fifteen years that indicates vitamin A has a role in metabolic disease prevention and causation. This literature proposes that vitamin A can affect obesity development and the development of obesity-related diseases including insulin resistance, type 2 diabetes, hepatic steatosis and steatohepatitis, and cardiovascular disease. Retinoic acid, the transcriptionally active form of vitamin A, accounts for many of the reported associations. However, a number of proteins involved in vitamin A metabolism, including retinol-binding protein 4 (RBP4) and aldehyde dehydrogenase 1A1 (ALDH1A1, alternatively known as retinaldehyde dehydrogenase 1 or RALDH1), have also been identified as being associated with metabolic disease. Some of the reported effects of these vitamin A-related proteins are proposed to be independent of their roles in assuring normal retinoic acid homeostasis. This review will consider both human observational data as well as published data from molecular studies undertaken in rodent models and in cells in culture. The primary focus of the review will be on the effects that vitamin A per se and proteins involved in vitamin A metabolism have on adipocytes, adipose tissue biology, and adipose-related disease, as well as on early stage liver disease, including non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH).
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Affiliation(s)
- William S Blaner
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, New York 10032.
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Zachariah JP, Quiroz R, Nelson KP, Teng Z, Keaney JF, Sullivan LM, Vasan RS. Prospective Relation of Circulating Adipokines to Incident Metabolic Syndrome: The Framingham Heart Study. J Am Heart Assoc 2017; 6:JAHA.116.004974. [PMID: 28713076 PMCID: PMC5586264 DOI: 10.1161/jaha.116.004974] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Background Adipokines are elaborated by adipose tissue and are associated with glycemic, lipid, and vascular traits. We hypothesized that in a cross‐sectional analysis circulating adipokines are altered among subsets of obesity stratified by presence versus absence of metabolic syndrome (MetS) and prospectively predict the incidence of MetS. Methods and Results Participants in the community‐based Framingham Third Generation Cohort who attended examination cycle 1 were included in the study (2002–2005; N=3777, mean age, 40 years; 59% women). Circulating adiponectin, leptin, leptin receptor, fetuin‐A, fatty acid–binding protein 4, and retinol binding protein 4 were assayed and related to incident MetS in follow‐up (mean 6 years). The adipokines were compared among individuals with excess body weight (body mass index ≥25 kg/m2) and prevalent MetS, excess body weight without MetS (metabolically healthy obese), and normal‐weight with MetS (metabolically obese, normal‐weight) with normal‐weight participants without MetS as a referent. Metabolically healthy obese individuals (n=1467) had higher circulating levels of fetuin‐A and fatty acid–binding protein 4 but lower levels of leptin, leptin receptor, and adiponectin (P<0.001 for all). The adipokine panel was associated with incident MetS (263 new‐onset cases; P=0.002). Higher circulating concentrations of retinol‐binding protein 4 and fetuin‐A were associated with incidence of MetS (odds ratio per 1‐SD increment log marker, 1.21; 95% CI, 1.03–1.41 [P=0.02] and 1.17; 95% CI, 1.01–1.34 [P=0.03], respectively). Conclusions In our community‐based sample of young to middle‐aged adults, metabolically healthy obese individuals demonstrated an adverse adipokine profile. Higher circulating levels of retinol‐binding protein 4 and fetuin‐A marked future cardiometabolic risk.
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Affiliation(s)
- Justin P Zachariah
- Section of Pediatric Cardiology, Department of Pediatrics, Texas Children's Hospital, Baylor College of Medicine, Houston, TX
| | - Rene Quiroz
- Cardiology Section, Boston University, Boston, MA
| | - Kerrie P Nelson
- Department of Biostatistics, Boston University School of Public Health, Boston, MA
| | - Zhaoyang Teng
- Department of Biostatistics, Boston University School of Public Health, Boston, MA
| | - John F Keaney
- Division of Cardiovascular Medicine, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Lisa M Sullivan
- Department of Biostatistics, Boston University School of Public Health, Boston, MA
| | - Ramachandran S Vasan
- Cardiology Section, Boston University, Boston, MA.,Preventive Medicine Section, Boston University, Boston, MA.,Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA.,Boston University's and the National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA
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9
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Jiao C, Cui L, Ma A, Li N, Si H. Elevated Serum Levels of Retinol-Binding Protein 4 Are Associated with Breast Cancer Risk: A Case-Control Study. PLoS One 2016; 11:e0167498. [PMID: 28002423 PMCID: PMC5176270 DOI: 10.1371/journal.pone.0167498] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 11/15/2016] [Indexed: 12/14/2022] Open
Abstract
Background Retinol binding protein 4 (RBP4) is a recently identified adipokine that is elevated in patients with obesity or type 2 diabetes. A growing body of research has shown that RBP4 is associated with several types of cancer. However, no studies have investigated the relationship between serum RBP4 levels and breast cancer risk. We performed a case-control study to evaluate the association between serum RBP4 levels and the risk of breast cancer. Methods From August 2012 to December 2013, four-hundred subjects including 200 patients diagnosed with primary breast cancer and 200 matched healthy women were consecutively enrolled from Affiliated Hospital of Qingdao University Medical College. Blood samples were collected from healthy controls and breast cancer patients before commencement of treatment. Enzyme-linked immunosorbent assay was used to evaluate the serum RBP4 levels in separated serum samples. Meanwhile, the characteristics of breast cancer cases and controls were collected from medical records and pathological data. Results The serum levels of RBP4 were significantly higher in patients with breast cancer than that in the healthy control group (33.77±9.92 vs. 28.77±6.47μg/ml, P < 0.05). Compared to the subjects in the lowest quartile of serum RBP4 level, the adjusted ORs (95% CIs) is 2.16(1.01–4.61) and 2.07 (1.07–4.00) for women in the second and highest RBP4 tertile, respectively. For breast cancer patients, patients with PR or ER negative displayed significantly higher serum RBP4 levels than those with PR or ER positive. Conclusion Our results for the first time suggested serum RBP4 levels could be associated with the risk of breast cancer. However, further prospective studies are essential to confirm these observed results.
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Affiliation(s)
- Congcong Jiao
- Department of Public Health, Medical College of Qingdao University, Qingdao, Shandong Province, China
| | - Lianhua Cui
- Department of Public Health, Medical College of Qingdao University, Qingdao, Shandong Province, China
- * E-mail:
| | - Aiguo Ma
- Department of Public Health, Medical College of Qingdao University, Qingdao, Shandong Province, China
| | - Na Li
- Department of Public Health, Medical College of Qingdao University, Qingdao, Shandong Province, China
| | - Hongzong Si
- Department of Public Health, Medical College of Qingdao University, Qingdao, Shandong Province, China
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Chang X, Yan H, Bian H, Xia M, Zhang L, Gao J, Gao X. Serum retinol binding protein 4 is associated with visceral fat in human with nonalcoholic fatty liver disease without known diabetes: a cross-sectional study. Lipids Health Dis 2015; 14:28. [PMID: 25890223 PMCID: PMC4419494 DOI: 10.1186/s12944-015-0033-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 04/08/2015] [Indexed: 12/30/2022] Open
Abstract
Background High serum Retinol Binding Protein 4 (RBP4) levels were associated with insulin-resistant states in humans. To determine which fat compartments are associated with elevated RBP4 levels in humans, we measured serum RBP4 and hepatic fat content (HFC), visceral (VFA) and subcutaneous abdominal fat area (SFA) in 106 subjects with non-alcoholic fatty liver disease (NAFLD) without known diabetes. Methods 106 patients with NAFLD (M/F: 61/45, aged 47.44 ± 14.16 years) were enrolled. Subjects with known diabetes, chronic virus hepatitis, and those with alcohol consumption ≥30 g/d in man and ≥20 g/d in woman were excluded. Anthropometrics and laboratory tests, including lipid profile, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and γ-glutamyltransferase (γ-GT) were conducted. HFC, VFA and SFA were determined by CT scan. Serum RBP4 was detected by an enzyme immunoassay kit and validated by quantitative Western blotting. Results Circulating RBP4 was negatively associated with high-density lipoprotein cholesterol (HDL-c) (r = −0.392, p < 0.001), but positively with waist-to-hip ratio (WHR) (r = 0.343, p = 0.001), triglyceride (r = 0.330, p = 0.002), VFA (r = 0.298, p = 0.027), systolic blood pressure (r = 0.247, p = 0.020), diastolic blood pressure (r = 0.241, p = 0.023), γ-GT (r = 0.239, p = 0.034), waist circumference (r = 0.218, p = 0.040). Differently, serum RBP4 levels were not associated with HFC (r = 0.199, p = 0.071), SFA, age, BMI, total cholesterol, low-density lipoprotein cholesterol (LDL-c), ALT or AST (all p > 0.05). Multiple linear regression analysis revealed that RBP4 correlated independently with VFA (Standard β = 0.357, p = 0.019) and HDL-c (Standard β = −0.345, p = 0.023) in all subjects, HDL-c (Standard β = −0.315, p = 0.040) in men, VFA/SFA in women (Standard β = 0.471, p = 0.049), not with HFC. However, serum RBP4 was positively correlated with HFC when HFC below 6.34% (r = 0.574, p = 0.001). Conclusions RBP4 could be a marker of abdominal obesity, however, the role of RBP4 in the pathogenesis of NAFLD is not sufficiently elucidated.
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Affiliation(s)
- Xinxia Chang
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
| | - Hongmei Yan
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
| | - Hua Bian
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
| | - Mingfeng Xia
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
| | - Linshan Zhang
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
| | - Jian Gao
- Department of clinical nutrition, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
| | - Xin Gao
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
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12
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Maresca F, Palma VD, Bevilacqua M, Uccello G, Taglialatela V, Giaquinto A, Esposito G, Trimarco B, Cirillo P. Adipokines, Vascular Wall, and Cardiovascular Disease. Angiology 2015; 66:8-24. [DOI: 10.1177/0003319713520463] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/29/2023]
Abstract
Epidemiological evidence has shown that abdominal obesity is closely associated with the development of cardiovascular (CV) disease, suggesting that it might be considered as an independent CV risk factor. However, the pathophysiological mechanisms responsible for the association between these 2 clinical entities remain largely unknown. Adipocytes are considered able to produce and secrete chemical mediators known as “adipokines” that may exert several biological actions, including those on heart and vessels. Of interest, a different adipokine profile can be observed in the plasma of patients with obesity or metabolic syndrome compared with healthy controls. We consider the main adipokines, focusing on their effects on the vascular wall and analyzing their role in CV pathophysiology.
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Affiliation(s)
- Fabio Maresca
- Department of Advanced Biomedical Sciences, Division of Cardiology, University of Naples, Naples, Italy
| | - Vito Di Palma
- Department of Advanced Biomedical Sciences, Division of Cardiology, University of Naples, Naples, Italy
| | - Michele Bevilacqua
- Department of Advanced Biomedical Sciences, Division of Cardiology, University of Naples, Naples, Italy
| | - Giuseppe Uccello
- Department of Advanced Biomedical Sciences, Division of Cardiology, University of Naples, Naples, Italy
| | - Vittorio Taglialatela
- Department of Advanced Biomedical Sciences, Division of Cardiology, University of Naples, Naples, Italy
| | - Alessandro Giaquinto
- Department of Advanced Biomedical Sciences, Division of Cardiology, University of Naples, Naples, Italy
| | - Giovanni Esposito
- Department of Advanced Biomedical Sciences, Division of Cardiology, University of Naples, Naples, Italy
| | - Bruno Trimarco
- Department of Advanced Biomedical Sciences, Division of Cardiology, University of Naples, Naples, Italy
| | - Plinio Cirillo
- Department of Advanced Biomedical Sciences, Division of Cardiology, University of Naples, Naples, Italy
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O'Byrne SM, Blaner WS. Retinol and retinyl esters: biochemistry and physiology. J Lipid Res 2013; 54:1731-43. [PMID: 23625372 PMCID: PMC3679378 DOI: 10.1194/jlr.r037648] [Citation(s) in RCA: 232] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 04/24/2013] [Indexed: 12/23/2022] Open
Abstract
By definition, a vitamin is a substance that must be obtained regularly from the diet. Vitamin A must be acquired from the diet, but unlike most vitamins, it can also be stored within the body in relatively high levels. For humans living in developed nations or animals living in present-day vivariums, stored vitamin A concentrations can become relatively high, reaching levels that can protect against the adverse effects of insufficient vitamin A dietary intake for six months, or even much longer. The ability to accumulate vitamin A stores lessens the need for routinely consuming vitamin A in the diet, and this provides a selective advantage to the organism. The molecular processes that underlie this selective advantage include efficient mechanisms to acquire vitamin A from the diet, efficient and overlapping mechanisms for the transport of vitamin A in the circulation, a specific mechanism allowing for vitamin A storage, and a mechanism for mobilizing vitamin A from these stores in response to tissue needs. These processes are considered in this review.
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Affiliation(s)
- Sheila M. O'Byrne
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - William S. Blaner
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY 10032
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Morikawa K, Hanada H, Hirota K, Nonaka M, Ikeda C. All-trans retinoic acid displays multiple effects on the growth, lipogenesis and adipokine gene expression of AML-I preadipocyte cell line. Cell Biol Int 2012; 37:36-46. [PMID: 23319320 DOI: 10.1002/cbin.10005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 09/05/2012] [Indexed: 01/09/2023]
Abstract
Adipose tissue is a potential site of retinoic acid (RA) action, but its physiological significance remains to be clarified. We have examined the effect of all-trans retinoic acid (ATRA) on growth and differentiation of preadipocytes, and on adipokine gene expression in mature adipocytes using human preadipocyte cell model, AML-I. Both ATRA and 9-cis RA induced growth arrest in AML-I preadipocyte at between 50 and 100 µM, which was accompanied by apoptosis. Western blotting showed a loss of NF-κB, Bcl-2 and p-Akt, and the accumulation of Bad and Akt in cytoplasm of ATRA-treated AML-I preadipocytes. Exposure of AML-I to ATRA or 9-cis RA increased intracellular lipid accumulation in a time-dependent manner compared to vehicle-treated cells. Expression of fatty acid synthase (FAS) and peroxisome proliferator-activated receptor-γ (PPAR-γ) proteins was increased in ATRA-treated cells. Thus, both ATRA and 9-cis RA promoted differentiation, inhibited proliferation and induced apoptosis in AML-I preadipocytes. ATRA also modulated adipokine expression by increasing the mRNA level of adipocytokines (adiponectin, leptin and LPL), and by inhibiting PAI-1 mRNA expression in mature AML-I adipocytes. The data suggest that ATRA exerts a wide range of effects--growth arrest, apoptosis, lipogenesis and modulation of adipokine gene expression--during the maturation of preadipocytes into adipocytes.
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Affiliation(s)
- Keiko Morikawa
- Division of Clinical Nutrition, Department of Nutritional Science, Sagami Women's University, 2-1-1 Bunkyo, Sagamihara, Kanagawa 228-8533, Japan.
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Abstract
Obesity has been associated with low-grade systemic inflammation and with micronutrient deficiencies. Obese individuals have been found to have lower vitamin A levels and lower vitamin A intake compared with normal-weight individuals. Vitamin A plays a major role in the immune function, including innate immunity, cell-mediated immunity and humoral antibody immunity. It has also been recognised recently that vitamin A has important regulatory functions. Vitamin A status has an important effect on the chronic inflammatory response. Vitamin A deficiency increases a T-helper type 1 (Th1) response, elevates levels of pro-inflammatory cytokines, increases the expression of leptin, resistin and uncoupling proteins (UCP) and promotes adipogenesis. The effect of vitamin A deficiency on obesity might be increasing the risk of fat deposition and also the risk of chronic inflammation associated with obesity. Supplementation with vitamin A in vitro and in animal models has been found to reduce concentrations of adipocytokines, such as leptin and resistin. In conclusion, vitamin A deficiency increases a Th1 response in the presence of obesity and thus, increases the inflammatory process involved in chronic inflammation and fat deposition. The metabolism of leptin and other adipocytokines may play a critical role in the effect of vitamin A deficiency in the inflammatory response observed in obesity.
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Lobo GP, Amengual J, Palczewski G, Babino D, von Lintig J. Mammalian carotenoid-oxygenases: key players for carotenoid function and homeostasis. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1821:78-87. [PMID: 21569862 PMCID: PMC3162997 DOI: 10.1016/j.bbalip.2011.04.010] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 04/19/2011] [Accepted: 04/26/2011] [Indexed: 12/31/2022]
Abstract
Humans depend on a dietary intake of lipids to maintain optimal health. Among various classes of dietary lipids, the physiological importance of carotenoids is still controversially discussed. On one hand, it is well established that carotenoids, such as β,β-carotene, are a major source for vitamin A that plays critical roles for vision and many aspects of cell physiology. On the other hand, large clinical trials have failed to show clear health benefits of carotenoids supplementation and even suggest adverse health effects in individuals at risk of disease. In recent years, key molecular players for carotenoid metabolism have been identified, including an evolutionarily well conserved family of carotenoid-oxygenases. Studies in knockout mouse models for these enzymes revealed that carotenoid metabolism is a highly regulated process and that this regulation already takes place at the level of intestinal absorption. These studies also provided evidence that β,β-carotene conversion can influence retinoid-dependent processes in the mouse embryo and in adult tissues. Moreover, these analyses provide an explanation for adverse health effects of carotenoids by showing that a pathological accumulation of these compounds can induce oxidative stress in mitochondria and cell signaling pathways related to disease. Advancing knowledge about carotenoid metabolism will contribute to a better understanding of the biochemical and physiological roles of these important micronutrients in health and disease. This article is part of a Special Issue entitled Retinoid and Lipid Metabolism.
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Affiliation(s)
- Glenn P. Lobo
- Case Western Reserve University, School of Medicine, Department of Pharmacology, Cleveland, OH 44106, USA
| | - Jaume Amengual
- Case Western Reserve University, School of Medicine, Department of Pharmacology, Cleveland, OH 44106, USA
| | - Grzegorz Palczewski
- Case Western Reserve University, School of Medicine, Department of Pharmacology, Cleveland, OH 44106, USA
| | - Darwin Babino
- Case Western Reserve University, School of Medicine, Department of Pharmacology, Cleveland, OH 44106, USA
| | - Johannes von Lintig
- Case Western Reserve University, School of Medicine, Department of Pharmacology, Cleveland, OH 44106, USA
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Abstract
Adipose tissue is an endocrine organ secreting biologically active factors called adipokines that act on both local and distant tissues. Adipokines have an important role in the development of obesity-related comorbidities not only in adults but also in children and adolescents. Retinol binding protein 4 (RBP4) is a recently identified adipokine suggested to link obesity with its comorbidities, especially insulin resistance, type 2 diabetes (T2D), and certain components of the metabolic syndrome. However, data, especially resulting from the clinical studies, are conflicting. In this review, we summarize up-to-date knowledge on RBP4's role in obesity, development of insulin resistance, and T2D. Special attention is given to studies on children and adolescents. We also discuss the role of possible confounding factors that should be taken into account when critically evaluating published studies or planning new studies on this exciting adipokine.
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Affiliation(s)
- Primoz Kotnik
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, University of Ulm, Ulm, Germany
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Bouchal P, Jarkovsky J, Hrazdilova K, Dvorakova M, Struharova I, Hernychova L, Damborsky J, Sova P, Vojtesek B. The new platinum-based anticancer agent LA-12 induces retinol binding protein 4 in vivo. Proteome Sci 2011; 9:68. [PMID: 22040120 PMCID: PMC3221626 DOI: 10.1186/1477-5956-9-68] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 10/31/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The initial pharmacokinetic study of a new anticancer agent (OC-6-43)-bis(acetato)(1-adamantylamine)amminedichloroplatinum (IV) (LA-12) was complemented by proteomic screening of rat plasma. The objective of the study was to identify new LA-12 target proteins that serve as markers of LA-12 treatment, response and therapy monitoring. METHODS Proteomic profiles were measured by surface-enhanced laser desorption-ionization time-of-flight mass spectrometry (SELDI-TOF MS) in 72 samples of rat plasma randomized according to LA-12 dose and time from administration. Correlation of 92 peak clusters with platinum concentration was evaluated using Spearman correlation analysis. RESULTS We identified Retinol-binding protein 4 (RBP4) whose level correlated with LA-12 level in treated rats. Similar results were observed in randomly selected patients involved in Phase I clinical trials. CONCLUSIONS RBP4 induction is in agreement with known RBP4 regulation by amantadine and cisplatin. Since retinol metabolism is disrupted in many cancers and inversely associates with malignancy, these data identify a potential novel mechanism for the action of LA-12 and other similar anti-cancer drugs.
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Affiliation(s)
- Pavel Bouchal
- Masaryk Memorial Cancer Institute, Regional Centre for Applied Molecular Oncology, Zluty kopec 7, 656 53 Brno, Czech Republic.
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Schreiber R, Taschler U, Preiss-Landl K, Wongsiriroj N, Zimmermann R, Lass A. Retinyl ester hydrolases and their roles in vitamin A homeostasis. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:113-23. [PMID: 21586336 PMCID: PMC3242165 DOI: 10.1016/j.bbalip.2011.05.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 04/28/2011] [Accepted: 05/02/2011] [Indexed: 12/16/2022]
Abstract
In mammals, dietary vitamin A intake is essential for the maintenance of adequate retinoid (vitamin A and metabolites) supply of tissues and organs. Retinoids are taken up from animal or plant sources and subsequently stored in form of hydrophobic, biologically inactive retinyl esters (REs). Accessibility of these REs in the intestine, the circulation, and their mobilization from intracellular lipid droplets depends on the hydrolytic action of RE hydrolases (REHs). In particular, the mobilization of hepatic RE stores requires REHs to maintain steady plasma retinol levels thereby assuring constant vitamin A supply in times of food deprivation or inadequate vitamin A intake. In this review, we focus on the roles of extracellular and intracellular REHs in vitamin A metabolism. Furthermore, we will discuss the tissue-specific function of REHs and highlight major gaps in the understanding of RE catabolism. This article is part of a Special Issue entitled Retinoid and Lipid Metabolism.
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20
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Lobo GP, Amengual J, Li HNM, Golczak M, Bonet ML, Palczewski K, von Lintig J. Beta,beta-carotene decreases peroxisome proliferator receptor gamma activity and reduces lipid storage capacity of adipocytes in a beta,beta-carotene oxygenase 1-dependent manner. J Biol Chem 2010; 285:27891-9. [PMID: 20573961 DOI: 10.1074/jbc.m110.132571] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Increasing evidence has been provided for a connection between retinoid metabolism and the activity of peroxisome proliferator receptors (Ppars) in the control of body fat reserves. Two different precursors for retinoids exist in the diet as preformed vitamin A (all-trans-retinol) and provitamin A (beta,beta-carotene). For retinoid production, beta,beta-carotene is converted to retinaldehyde by beta,beta-carotene monooxygenase 1 (Bcmo1). Previous analysis showed that Bcmo1 knock-out mice develop dyslipidemia and are more susceptible to diet-induced obesity. However, the role of Bcmo1 for adipocyte retinoid metabolism has yet not been well defined. Here, we showed that Bcmo1 mRNA and protein expression are induced during adipogenesis in NIH 3T3-L1 cells. In mature adipocytes, beta,beta-carotene but not all-trans-retinol was metabolized to retinoic acid (RA). RA decreased the expression of Ppar gamma and CCAAT/enhancer-binding protein alpha, key lipogenic transcription factors, and reduced the lipid content of mature adipocytes. This process was inhibited by the retinoic acid receptor antagonist LE450, showing that it involves canonical retinoid signaling. Accordingly, gavage of beta,beta-carotene but not all-trans-retinol induced retinoid signaling and decreased Ppar gamma expression in white adipose tissue of vitamin A-deficient mice. Our study identifies beta,beta-carotene as a critical physiological precursor for RA production in adipocytes and implicates provitamin A as a dietary regulator of body fat reserves.
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Affiliation(s)
- Glenn P Lobo
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, USA
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21
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Karastergiou K, Mohamed-Ali V. The autocrine and paracrine roles of adipokines. Mol Cell Endocrinol 2010; 318:69-78. [PMID: 19948207 DOI: 10.1016/j.mce.2009.11.011] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 11/16/2009] [Accepted: 11/23/2009] [Indexed: 12/23/2022]
Abstract
Obesity, defined by an excess of adipose tissue, is often associated with the development of various metabolic diseases. The increased and inappropriate deposition of this tissue contributes to hyperglycemia, hyperlipidemia, insulin resistance, endothelial dysfunction and chronic inflammation. Recent evidence suggests that factors expressed and secreted by the adipose tissue, adipokines, may contribute to the development of these abnormalities by mechanisms including inhibition of adipogenesis, adipocyte hypertrophy and death, immune cell infiltration and disruption of tissue metabolism. The presence of adipokine receptors in adipocytes renders these cells available to autocrine and paracrine effects of adipokines. In this review the reported local effects of adipokines on adipose tissue structure, inflammation and regulation of metabolic functions, in the face of over-nutrition and consequent obesity, are outlined. Elucidating the local regulation of white adipocyte development and function could help in the design of effective, tissue-specific therapies for obesity-associated diseases.
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Affiliation(s)
- Kalypso Karastergiou
- Adipokines and Metabolism Research Group, Centre for Clinical Pharmacology, Division of Medicine, University College London, 5 University Street, London WC1E 6JJ, UK
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22
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Ström K, Gundersen TE, Hansson O, Lucas S, Fernandez C, Blomhoff R, Holm C. Hormone-sensitive lipase (HSL) is also a retinyl ester hydrolase: evidence from mice lacking HSL. FASEB J 2009; 23:2307-16. [PMID: 19246492 DOI: 10.1096/fj.08-120923] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Here, we investigated the importance of hormone-sensitive lipase (HSL) as a retinyl ester hydrolase (REH). REH activity was measured in vitro using recombinant HSL and retinyl palmitate. The expression of retinoic acid (RA)-regulated genes and retinoid metabolites were measured in high-fat diet fed HSL-null mice using real-time quantitative PCR and triple-stage liquid chromatography/tandem mass spectrometry, respectively. Age- and gender-matched wild-type littermates were used as controls. The REH activity of rat HSL was found to be higher than that against the hitherto best known HSL substrate, i.e., diacylglycerols. REH activity in white adipose tissue (WAT) of HSL-null mice was completely blunted and accompanied by increased levels of retinyl esters and decreased levels of retinol, retinaldehyde and all-trans RA. Accordingly, genes known to be positively regulated by RA were down-regulated in HSL-null mice, including pRb and RIP140, key factors promoting differentiation into the white over the brown adipocyte lineage. Dietary RA supplementation partly restored WAT mass and the expression of RA-regulated genes in WAT of HSL-null mice. These findings demonstrate the importance of HSL as an REH of adipose tissue and suggest that HSL via this action provides RA and other retinoids for signaling events that are crucial for adipocyte differentiation and lineage commitment.
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Affiliation(s)
- Kristoffer Ström
- Division of Diabetes, Metabolism and Endocrinology, Department of Experimental Medical Science, Lund University, BMC C11, SE-221 84 Lund, Sweden.
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23
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Hassink S, Balagopal PB. RBP4: from retinol transporter to biomarker? J Pediatr 2009; 154:5-7. [PMID: 19187729 DOI: 10.1016/j.jpeds.2008.08.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Accepted: 08/13/2008] [Indexed: 10/21/2022]
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Affiliation(s)
- Sheila M O'Byrne
- a Division of Preventive Medicine and Nutrition, Department of Medicine, College of Physicians and Surgeons, Columbia University, 650 West 168th Street, New York, NY 10032, USA.
| | - William S Blaner
- b Division of Preventive Medicine and Nutrition, Department of Medicine, College of Physicians and Surgeons, Columbia University, 650 West 168th Street, New York, NY 10032, USA.
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25
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von Eynatten M, Humpert PM. Retinol-binding protein-4 in experimental and clinical metabolic disease. Expert Rev Mol Diagn 2008; 8:289-99. [PMID: 18598108 DOI: 10.1586/14737159.8.3.289] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Retinol-binding protein-4 (RBP4), a 21-kDa protein synthesized in the liver and adipose tissue, has recently been described as a murine adipokine involved in the development of insulin resistance. The expression of the gene encoding RBP4 was increased in the adipose tissue, but not in the liver, of insulin-resistant adipose GLUT4(-/-) mice and five other mouse models of obesity and insulin resistance. In addition, intraperitoneal injection or transgenic overexpression of RBP4 in mice induced insulin resistance. While experimental clinical approaches (mostly applying clamp techniques) in humans confirmed correlations of RBP4 with insulin resistance, studies in larger groups out of clinical routine failed to demonstrate a connection with alternative measures of insulin sensitivity. Yet, significant associations of RBP4 with atherogenic lipids were found and a focus of future studies should be the influence on atherosclerosis and related complications. Based on current data, the function of RBP4 as an adipokine exerting metabolic effects in glucose metabolism in humans remains uncertain and might be restricted to rodent models.
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26
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Arana A, Mendizabal JA, Alzón M, Soret B, Purroy A. The effect of vitamin A supplementation on postnatal adipose tissue development of lambs. J Anim Sci 2008; 86:3393-400. [PMID: 18676724 DOI: 10.2527/jas.2008-0889] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Vitamin A (retinoic acid) is known to be an adipogenic factor influencing both in vitro and in vivo cell development. This study aimed to determine its effect on lamb adipose tissue development during the early phase of postnatal development until 100 d of age. Male lambs (n = 24) of the Rasa Aragonesa breed were used. At birth, lambs were assigned to 1 of 2 experimental groups: 1) the control (C) group, which received feed without vitamin A supplementation, and 2) the vitamin A (V) group, which received a supplement of 500,000 IU/animal twice per week from birth to slaughter. The effect of vitamin A supplementation was studied at 16.8 +/- 0.35 kg of BW (58 +/- 0.7 d of age) and at 27.8 +/- 0.78 kg of BW (101 +/- 6.5 d of age). The variables of lamb growth, carcass, LM area, and lipid content were analyzed. To study adipose tissue development, the amount of adipose tissue accumulated, the size and number of adipocytes, and lipogenic enzyme activities (glycerol 3-phosphate dehydrogenase, fatty acid synthase, and glucose 6-phosphate dehydrogenase) of the omental, perirenal, and s.c. depots were quantified. Results showed that vitamin A supplementation had no influence on growth, carcass variables, LM area, and lipid content during lamb growth but that the number of adipocytes in the perirenal depot was 30% greater in lambs of the V group (P < 0.05) and that these lambs had smaller adipocytes in the omental and perirenal depots (P = 0.06) at 28 kg of BW (101 d of age). These results suggest that the intake of this level of vitamin A during the whole period of growth of the lambs influenced the processes of hyperplasia and hypertrophy in the different adipose depots, depending on their degree of maturity.
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Affiliation(s)
- A Arana
- Escuela Técnica Superior de Ingenieros Agrónomos, Universidad Pública Navarra, Campus de Arrosadía, 31006 Pamplona, Spain
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Wongsiriroj N, Piantedosi R, Palczewski K, Goldberg IJ, Johnston TP, Li E, Blaner WS. The molecular basis of retinoid absorption: a genetic dissection. J Biol Chem 2008; 283:13510-9. [PMID: 18348983 PMCID: PMC2376245 DOI: 10.1074/jbc.m800777200] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 03/13/2008] [Indexed: 11/06/2022] Open
Abstract
The intestine and other tissues are able to synthesize retinyl esters in an acyl-CoA-dependent manner involving an acyl-CoA:retinol acyltransferase (ARAT). However, the molecular identity of this ARAT has not been established. Recent studies of lecithin:retinol acyltransferase (LRAT)-deficient mice indicate that LRAT is responsible for the preponderance of retinyl ester synthesis in the body, aside from in the intestine and adipose tissue. Our present studies, employing a number of mutant mouse models, identify diacylglycerol acyltransferase 1 (DGAT1) as an important intestinal ARAT in vivo. The contribution that DGAT1 makes to intestinal retinyl ester synthesis becomes greater when a large pharmacologic dose of retinol is administered by gavage to mice. Moreover, when large retinol doses are administered another intestinal enzyme(s) with ARAT activity becomes apparent. Surprisingly, although DGAT1 is expressed in adipose tissue, DGAT1 does not catalyze retinyl ester synthesis in adipose tissue in vivo. Our data also establish that cellular retinol-binding protein, type II (CRBPII), which is expressed solely in the adult intestine, in vivo channels retinol to LRAT for retinyl ester synthesis. Contrary to what has been proposed in the literature based on in vitro studies, CRBPII does not directly prevent retinol from being acted upon by DGAT1 or other intestinal ARATs in vivo.
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Affiliation(s)
- Nuttaporn Wongsiriroj
- Institute of Human Nutrition and Department of Medicine, Columbia University, New York, New York 10032, USA
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28
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Shea J, Randell E, Vasdev S, Wang PP, Roebothan B, Sun G. Serum retinol-binding protein 4 concentrations in response to short-term overfeeding in normal-weight, overweight, and obese men. Am J Clin Nutr 2007; 86:1310-5. [PMID: 17991640 DOI: 10.1093/ajcn/86.5.1310] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Retinol-binding protein 4 (RBP4) is a novel adipokine that induces insulin resistance in mice. Studies in humans have shown a correlation between serum RBP4 and insulin resistance in obese subjects and in subjects with type 2 diabetes. Few data are available regarding the nutritional regulation of RBP4. OBJECTIVE The study investigated the relation of RBP4 with phenotypes of glucose and lipid metabolism at baseline and in response to a 7-d overfeeding protocol in young men. DESIGN Sixty-five men participated in the study. Subjects were classified on the basis of body mass index (BMI; kg/m(2)) as normal-weight (</=24.9) or as overweight or obese (>/=25.0). Serum RBP4, interleukin-6, visfatin, glucose, insulin, total cholesterol, HDL cholesterol, and LDL cholesterol (calculated), and triacylglycerols were measured. Insulin resistance and beta cell function were assessed by using the homeostasis model. Percentage body fat was measured by using dual-energy X-ray absorptiometry. RESULTS No significant differences were found in serum RBP4 between the 2 groups at baseline. Likewise, no significant differences were observed in fasting serum RBP4 in response to overfeeding. Baseline RBP4 was negatively correlated with the change in insulin resistance in normal-weight subjects, independent of age and BMI. No significant correlation was found between serum RBP4 and visfatin, interleukin-6, or any other variables measured. CONCLUSIONS Short-term overfeeding did not induce significant changes in RBP4. Baseline RBP4 concentrations may predict insulin resistance when exposed to a positive energy challenge in normal-weight men.
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Affiliation(s)
- Jennifer Shea
- Discipline of Genetics and Medicine, Faculty of Medicine, Memorial University of Newfoundland, St John's, Canada
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29
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Broch M, Vendrell J, Ricart W, Richart C, Fernández-Real JM. Circulating retinol-binding protein-4, insulin sensitivity, insulin secretion, and insulin disposition index in obese and nonobese subjects. Diabetes Care 2007; 30:1802-6. [PMID: 17416795 DOI: 10.2337/dc06-2034] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Recent investigations disclosed an upregulation of retinol-binding protein-4 (RBP4) in the adipose tissue of several insulin-resistant mouse models and increased serum RBP4 concentration in subjects with obesity and type 2 diabetes in association with insulin resistance. There is some experimental evidence that RBP4 also could been linked to insulin secretion. RESEARCH DESIGN AND METHODS We aimed to evaluate insulin secretion, insulin sensitivity, insulin disposition index (minimal model analysis), and circulating RBP4 (enzyme-linked immunosorbent assay) in nondiabetic men with a wide range of obesity (n = 107). RESULTS Serum RBP4 concentration was nonsignificantly different among lean, overweight, and obese subjects. Circulating RBP4 was not associated with age, BMI, waist-to-hip ratio, or metabolic parameters, including insulin sensitivity (r = -0.03, P = 0.6). On the contrary, circulating RBP4 was negatively associated with insulin secretion, especially in obese subjects (r = -0.48, P = 0.007), in whom RBP4 also was linked to insulin disposition index (r = -0.44, P = 0.01). On multiple regression analyses to predict insulin secretion (acute insulin response [AIR(g)]), insulin sensitivity was the only factor that contributed to 17% of AIR(g) variance in nonobese subjects. In obese subjects, however, RBP4 emerged as an independent factor that contributed independently to AIR(g) variance (23%). CONCLUSIONS Our results suggest that oversecretion of RBP4 may negatively affect beta-cell function directly or by preventing the binding of transthyretin to its receptor. These mechanisms could be behind the association between increased circulating RBP4 and type 2 diabetes. RBP4 could be one signal from insulin-resistant tissues that impacts on beta-cell secretion.
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Affiliation(s)
- Montserrat Broch
- Reseach Unit, Pere Virgili Institute for Biomedical Research, Tarragona, Spain
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30
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Stefan N, Hennige AM, Staiger H, Machann J, Schick F, Schleicher E, Fritsche A, Häring HU. High circulating retinol-binding protein 4 is associated with elevated liver fat but not with total, subcutaneous, visceral, or intramyocellular fat in humans. Diabetes Care 2007; 30:1173-8. [PMID: 17259477 DOI: 10.2337/dc06-2342] [Citation(s) in RCA: 173] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Retinol-binding protein 4 (RBP4) is an adipokine that induced insulin resistance in mice, and high plasma RBP4 levels were associated with insulin-resistant states in humans. To determine which fat compartments are associated with elevated RBP4 levels in humans, we measured circulating RBP4 in 75 healthy subjects and used state-of-the-art measurements of body fat distribution. RESEARCH DESIGN AND METHODS Total body, visceral, and subcutaneous abdominal fat were determined by magnetic resonance tomography and liver fat and intramyocellular fat by localized proton magnetic resonance spectroscopy. Insulin sensitivity was measured by the euglycemic-hyperinsulinemic clamp and, together with insulin clearance, estimated from the oral glucose tolerance test (OGTT). RESULTS Adjusted circulating RBP4 correlated negatively with insulin sensitivity (clamp: r = -0.33, P = 0.005; OGTT: r = -0.36, P = 0.002) and positively with parameters in the fasting state as insulin levels (r = 0.35, P = 0.003) and homeostasis model assessment of insulin resistance (r = 0.34, P = 0.004). In addition, circulating RBP4 correlated negatively with hepatic insulin clearance (r = -0.25, P = 0.04). Circulating RBP4 was not associated with total body, visceral, or subcutaneous abdominal fat (all P > or = 0.29). Plasma RBP4 levels were also not associated with intramyocellular fat or circulating adiponectin or leptin. In contrast, plasma RBP4 levels correlated positively with liver fat in cross-sectional (r = 0.27, P = 0.03) and longitudinal (r = 0.37, P = 0.04) analyses. CONCLUSIONS Circulating RBP4 is not associated with the amount of fat in the classical depots or in the ectopic depots in muscle. However, it correlates positively with liver fat. Furthermore, metabolic parameters support the close relationship between circulating RBP4 with liver fat and, presumably, hepatic insulin resistance.
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Affiliation(s)
- Norbert Stefan
- Division of Endocrinology, Diabetology, Nephrology, Vascular Disease, and Clinical Chemistry, Department of Internal Medicine, University of Tübingen, D-72076 Tübingen, Germany.
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31
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Moise AR, Noy N, Palczewski K, Blaner WS. Delivery of retinoid-based therapies to target tissues. Biochemistry 2007; 46:4449-58. [PMID: 17378589 PMCID: PMC2562735 DOI: 10.1021/bi7003069] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Through its various metabolites, vitamin A controls essential physiological functions. Both naturally occurring metabolites and novel retinoid analogues have shown effectiveness in many clinical settings that include skin diseases and cancer, and in animal models of human conditions affecting vision. In this review, we analyze several potential retinoid-based therapies from the point of view of drug metabolism and transport to target tissues. We focus on the endogenous factors that affect the absorption, transport, and metabolism of retinoids by taking into account data obtained from the analysis of animal models that lack the enzymes or proteins involved in the storage and absorption of retinoids. We also discuss findings of toxicity associated with retinoids in an effort to improve the outcome of retinoid-based therapies. In this context, we review evidence that esterification of retinol and retinol-based drugs within target tissues provides one of the most efficient means to improve the absorption and to reduce the toxicity associated with pharmacological doses of retinoids. Future retinoid-based therapeutic strategies could involve targeted delivery mechanisms leading to lower toxicity and improved effectiveness of retinoids.
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Affiliation(s)
- Alexander R Moise
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965, USA.
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32
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Janke J, Engeli S, Boschmann M, Adams F, Böhnke J, Luft FC, Sharma AM, Jordan J. Retinol-binding protein 4 in human obesity. Diabetes 2006; 55:2805-10. [PMID: 17003346 DOI: 10.2337/db06-0616] [Citation(s) in RCA: 253] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Studies in mice suggest that adipocytes serve as glucose sensors and regulate systemic glucose metabolism through release of serum retinol-binding protein 4 (RBP4). This model has not been validated in humans. RBP4 was highly expressed in isolated mature human adipocytes and secreted by differentiating human adipocytes. In contrast to the animal data, RBP4 mRNA was downregulated in subcutaneous adipose tissue of obese women, and circulating RBP4 concentrations were similar in normal weight, overweight, and obese women (n = 74). RBP4 was positively correlated with GLUT4 expression in adipose tissue, independent of any obesity-associated variable. Five percent weight loss slightly decreased adipose RBP4 expression but did not influence circulating RBP4. In another set of experiments, we stratified patients (n = 14) by low or high basal fasting interstitial glucose concentrations, as determined by the microdialysis technique. Venous glucose concentrations were similar throughout oral glucose tolerance testing, and basal RBP4 expression in adipose tissue and serum RBP4 concentrations were similar in the groups with higher and lower interstitial glucose levels. Our findings point to profound differences between rodents and humans in the regulation of adipose or circulating RBP4 and challenge the notion that glucose uptake by adipocytes has a dominant role in the regulation of RBP4.
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Affiliation(s)
- Jürgen Janke
- Franz Volhard Clinical Research Center (Haus 129), Charité Campus Buch, Wiltbergstr. 50, 13125 Berlin, Germany
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O’Byrne SM, Wongsiriroj N, Libien J, Vogel S, Goldberg IJ, Baehr W, Palczewski K, Blaner WS. Retinoid absorption and storage is impaired in mice lacking lecithin:retinol acyltransferase (LRAT). J Biol Chem 2005; 280:35647-57. [PMID: 16115871 PMCID: PMC1352312 DOI: 10.1074/jbc.m507924200] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lecithin:retinol acyltransferase (LRAT) is believed to be the predominant if not the sole enzyme in the body responsible for the physiologic esterification of retinol. We have studied Lrat-deficient (Lrat-/-) mice to gain a better understanding of how these mice take up and store dietary retinoids and to determine whether other enzymes may be responsible for retinol esterification in the body. Although the Lrat-/- mice possess only trace amounts of retinyl esters in liver, lung, and kidney, they possess elevated (by 2-3-fold) concentrations of retinyl esters in adipose tissue compared with wild type mice. These adipose retinyl ester depots are mobilized in times of dietary retinoid insufficiency. We further observed an up-regulation (3-4-fold) in the level of cytosolic retinol-binding protein type III (CRBPIII) in adipose tissue of Lrat-/- mice. Examination by electron microscopy reveals a striking total absence of large lipid-containing droplets that normally store hepatic retinoid within the hepatic stellate cells of Lrat-/- mice. Despite the absence of significant retinyl ester stores and stellate cell lipid droplets, the livers of Lrat-/- mice upon histologic analysis appear normal and show no histological signs of liver fibrosis. Lrat-/- mice absorb dietary retinol primarily as free retinol in chylomicrons; however, retinyl esters are also present within the chylomicron fraction obtained from Lrat-/- mice. The fatty acyl composition of these (chylomicron) retinyl esters suggests that they are synthesized via an acyl-CoA-dependent process suggesting the existence of a physiologically significant acyl-CoA:retinol acyltransferase.
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Affiliation(s)
- Sheila M. O’Byrne
- From the Institute of Human Nutrition and
- Medicine, College of Physicians and Surgeons, Columbia University, New York, New York 10032, the
| | - Nuttaporn Wongsiriroj
- From the Institute of Human Nutrition and
- Medicine, College of Physicians and Surgeons, Columbia University, New York, New York 10032, the
| | | | - Silke Vogel
- Medicine, College of Physicians and Surgeons, Columbia University, New York, New York 10032, the
| | - Ira J. Goldberg
- From the Institute of Human Nutrition and
- Medicine, College of Physicians and Surgeons, Columbia University, New York, New York 10032, the
| | - Wolfgang Baehr
- Department of Ophthalmology, the University of Utah Health Sciences Center, Salt Lake City, Utah 84112, and the
| | - Krzysztof Palczewski
- Departments of Ophthalmology, Pharmacology and Chemistry, the University of Washington, Seattle, Washington 98185
| | - William S. Blaner
- From the Institute of Human Nutrition and
- Medicine, College of Physicians and Surgeons, Columbia University, New York, New York 10032, the
- To whom correspondence should be addressed: Dept. of Medicine, Columbia University, 701 W. 168th St., New York, NY 10032. Tel.: 212-305-5429; Fax: 212-305-2801; E-mail:
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Yang Q, Graham TE, Mody N, Preitner F, Peroni OD, Zabolotny JM, Kotani K, Quadro L, Kahn BB. Serum retinol binding protein 4 contributes to insulin resistance in obesity and type 2 diabetes. Nature 2005; 436:356-62. [PMID: 16034410 DOI: 10.1038/nature03711] [Citation(s) in RCA: 1481] [Impact Index Per Article: 77.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Accepted: 05/03/2005] [Indexed: 01/08/2023]
Abstract
In obesity and type 2 diabetes, expression of the GLUT4 glucose transporter is decreased selectively in adipocytes. Adipose-specific Glut4 (also known as Slc2a4) knockout (adipose-Glut4(-/-)) mice show insulin resistance secondarily in muscle and liver. Here we show, using DNA arrays, that expression of retinol binding protein-4 (RBP4) is elevated in adipose tissue of adipose-Glut4(-/-) mice. We show that serum RBP4 levels are elevated in insulin-resistant mice and humans with obesity and type 2 diabetes. RBP4 levels are normalized by rosiglitazone, an insulin-sensitizing drug. Transgenic overexpression of human RBP4 or injection of recombinant RBP4 in normal mice causes insulin resistance. Conversely, genetic deletion of Rbp4 enhances insulin sensitivity. Fenretinide, a synthetic retinoid that increases urinary excretion of RBP4, normalizes serum RBP4 levels and improves insulin resistance and glucose intolerance in mice with obesity induced by a high-fat diet. Increasing serum RBP4 induces hepatic expression of the gluconeogenic enzyme phosphoenolpyruvate carboxykinase (PEPCK) and impairs insulin signalling in muscle. Thus, RBP4 is an adipocyte-derived 'signal' that may contribute to the pathogenesis of type 2 diabetes. Lowering RBP4 could be a new strategy for treating type 2 diabetes.
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Affiliation(s)
- Qin Yang
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA
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35
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Kindblom JM, Gevers EF, Skrtic SM, Lindberg MK, Göthe S, Törnell J, Vennström B, Ohlsson C. Increased adipogenesis in bone marrow but decreased bone mineral density in mice devoid of thyroid hormone receptors. Bone 2005; 36:607-16. [PMID: 15780976 DOI: 10.1016/j.bone.2005.01.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2004] [Revised: 12/06/2004] [Accepted: 01/11/2005] [Indexed: 01/02/2023]
Abstract
Mice deficient for all known thyroid hormone receptors, TRalpha1-/-beta-/- mice, display a clear skeletal phenotype characterized by growth retardation, delayed maturation of long bones and decreased trabecular and total bone mineral density (BMD; -14.6 +/- 2.8%, -14.4 +/- 1.5%). The aim of the present study was to investigate the molecular mechanisms behind the skeletal phenotype in TRalpha1-/-beta-/- mice. Global gene expression analysis was performed on total vertebrae from wild-type (WT) and TRalpha1-/-beta-/- mice using DNA microarray and the results were verified by real-time PCR. The mRNA levels of six genes (AdipoQ, Adipsin, Fat-Specific Protein 27 (FSP 27), lipoprotein lipase (LPL), retinol-binding protein (RBP) and phosphoenolpyruvate carboxykinase (PEPCK)) expressed by mature adipocytes were increased in TRalpha1-/-beta-/- compared with WT mice. An increased amount of fat (225% over WT) due to an increased number but unchanged mean size of adipocytes in the bone marrow of TRalpha1-/-beta-/- mice was revealed. Interestingly, the mRNA levels of the key regulator of osteoclastogenesis, receptor activator of NF-varkappab ligand (RANKL), were dramatically decreased in TRalpha1-/-beta-/- mice. In conclusion, TRalpha1-/-beta-/- mice demonstrated increased expression of adipocyte specific genes and an increased amount of bone marrow fat. Thus, these mice have increased adipogenesis in bone marrow associated with decreased trabecular bone mineral density (BMD). One may speculate that these effects either could be caused by an imbalance in the differentiation of the osteoblast and the adipocyte lineages at the expense of osteoblastogenesis, or by independent effects on the regulation of both osteoblastogenesis and adipogenesis.
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Affiliation(s)
- Jenny M Kindblom
- Center for Bone Research at the Sahlgrenska Academy, RCEM, Department of Internal Medicine, The Sahlgrenska Academy at Gothenburg University, Sweden.
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Lapshina EA, Belyaeva OV, Chumakova OV, Kedishvili NY. Differential recognition of the free versus bound retinol by human microsomal retinol/sterol dehydrogenases: characterization of the holo-CRBP dehydrogenase activity of RoDH-4. Biochemistry 2003; 42:776-84. [PMID: 12534290 DOI: 10.1021/bi026836r] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
All-trans-retinol is the precursor for all-trans-retinoic acid, the activating ligand for nuclear transcription factors retinoic acid receptors. In the cytosol of various cells, most retinol exists in a bound form, complexed with cellular retinol binding protein type I (holo-CRBP). Whether retinoic acid is produced from the free or bound form of retinol is not yet clear. Here, we present evidence that holo-CRBP is recognized as substrate by human microsomal short-chain dehydrogenase/reductase (SDR) RoDH-4 with the K(m) value close to the liver concentration of holo-CRBP. The ability to utilize holo-CRBP differentiates RoDH-4 from a related enzyme, RoDH-like 3alpha-hydroxysteroid dehydrogenase (3alpha-HSD), which is 3-fold more active with free retinol than RoDH-4 but is 15-fold less active toward holo-CRBP. Recognition of the cytosolic holo-CRBP as substrate is consistent with RoDH-4 orientation in the membrane. As established by immunoprecipitation and glycosylation scanning, RoDH-4 faces the cytosolic side of the membrane. Purified RoDH-4, stabilized by reconstitution into proteoliposomes, exhibits the apparent K(m) values for substrates and NAD(+) similar to those of the microsomal enzyme and oxidizes holo-CRBP with the catalytic efficiency (k(cat)/K(m)) of 59 min(-1) mM(-1). Apo-CRBP acts as a strong competitive inhibitor of holo-CRBP oxidation with an apparent K(i) value of 0.2 microM. The results of this study suggest that the human retinol-active SDRs are not functionally equivalent and that, in contrast to RoDH-like 3alpha-HSD, RoDH-4 can access the bound form of retinol for retinoic acid production and is regulated by the apo-/holo-CRBP ratio.
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Affiliation(s)
- Elena A Lapshina
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, Missouri 64110, USA
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37
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Redonnet A, Bonilla S, Noël-Suberville C, Pallet V, Dabadie H, Gin H, Higueret P. Relationship between peroxisome proliferator-activated receptor gamma and retinoic acid receptor alpha gene expression in obese human adipose tissue. Int J Obes (Lond) 2002; 26:920-7. [PMID: 12080444 DOI: 10.1038/sj.ijo.0802025] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2001] [Revised: 02/11/2002] [Accepted: 02/14/2002] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To investigate in human adipose tissue a possible relationship between per oxisome proliferator-activated receptor gamma (PPARgamma) and retinoic acid receptor alpha (RARalpha) gene expression, two genes involved in the control of adipocyte differentiation. SUBJECTS Ten lean control women (age 31-60 y, body mass index (BMI) 18-24.7 kg/m(2)) and an obese group of 15 women (age 27-62 y, BMI 30-57.5 kg/m(2)), of whom 10 subjects were in weight-gain phase and five were in weight-loss phase. MEASUREMENTS We assessed the relative PPARgamma and RARalpha mRNA levels in subcutaneous abdominal adipose tissue using a real-time PCR method. RESULTS PPARgamma mRNA level were significantly increased (+91%; P<0.01) in obese women compared to lean control women. In the obese group, we observed a PPARgamma mRNA level 42% lower in weight-loss obese than in weight-gain obese subjects. We obtained a positive correlation (r=0.56; P<0.01) between PPARgamma mRNA level and the BMI of all subjects. Relative mRNA abundance level of RARalpha in subcutaneous adipose tissue of obese subjects is significantly lower than in control subjects (-56%, P<0.01), and a negative correlation was found between PPARgamma and RARalpha mRNA levels in subcutaneous adipose tissue of subjects study (r=-0.75; P<0.01). CONCLUSION Our findings suggest that obesity is associated with an inverse relationship between PPARgamma and RARalpha expressions in human subcutaneous adipose tissue. Modulations of nuclear receptor profile could be an important event in the body's early adaptive mechanisms promoting adipose tissue plasticity and leading to the onset of obesity.
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Affiliation(s)
- A Redonnet
- Laboratoire de Nutrition et Signalisation Cellulaire (USC-INRA), ISTAB, Université Bordeaux I, Talence, France
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38
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Trayhurn P, Beattie JH. Physiological role of adipose tissue: white adipose tissue as an endocrine and secretory organ. Proc Nutr Soc 2001; 60:329-39. [PMID: 11681807 DOI: 10.1079/pns200194] [Citation(s) in RCA: 760] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The traditional role attributed to white adipose tissue is energy storage, fatty acids being released when fuel is required. The metabolic role of white fat is, however, complex. For example, the tissue is needed for normal glucose homeostasis and a role in inflammatory processes has been proposed. A radical change in perspective followed the discovery of leptin; this critical hormone in energy balance is produced principally by white fat, giving the tissue an endocrine function. Leptin is one of a number of proteins secreted from white adipocytes, which include angiotensinogen, adipsin, acylation-stimulating protein, adiponectin, retinol-binding protein, tumour neorosis factor a, interleukin 6, plasminogen activator inhibitor-1 and tissue factor. Some of these proteins are inflammatory cytokines, some play a role in lipid metabolism, while others are involved in vascular haemostasis or the complement system. The effects of specific proteins maybe autocrine or paracrine, or the site of action maybe distant from adipose tissue. The most recently described adipocyte secretory proteins are fasting-induced adipose factor, a fibrinogen-angiopoietin-related protein, metallothionein and resistin. Resistin is an adipose tissue-specific factor which is reported to induce insulin resistance, linking diabetes to obesity. Metallothionein is a metal-binding and stress-response protein which may have an antioxidant role. The key challenges in establishing the secretory functions of white fat are to identify the complement of secreted proteins, to establish the role of each secreted protein, and to assess the pathophysiological consequences of changes in adipocyte protein production with alterations in adiposity (obesity, fasting, cachexia). There is already considerable evidence of links between increased production of some adipocyte factors and the metabolic and cardiovascular complications of obesity. In essence, white adipose tissue is a major secretory and endocrine organ involved in a range of functions beyond simple fat storage.
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Affiliation(s)
- P Trayhurn
- Institute for Nutrition Research, University of Oslo, Blindern, Norway.
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Garcia, Lacasa, Agli, Giudicelli, Castelli. Antiadipogenic properties of retinol in primary cultured differentiating human adipocyte precursor cells. Int J Cosmet Sci 2000; 22:95-103. [DOI: 10.1046/j.1467-2494.2000.00018.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Scantlebury T, Maslowska M, Cianflone K. Chylomicron-specific enhancement of acylation stimulating protein and precursor protein C3 production in differentiated human adipocytes. J Biol Chem 1998; 273:20903-9. [PMID: 9694837 DOI: 10.1074/jbc.273.33.20903] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acylation stimulating protein (ASP) is a potent stimulator of adipocyte triacylglycerol storage. In vivo studies have shown that ASP production by adipocytes increases locally after a fat meal. Initial in vitro studies demonstrated increased production of ASP in the presence of chylomicrons (CHYLO). The present aim was to define the CHYLO component responsible. None of the apoproteins tested (AI, AII, AIV, CI, CII, CIII, and E) were capable of stimulating C3 (the precursor protein) or ASP production. Rather, the active component is a nonlipid, loosely associated, trypsin-sensitive molecule. High pressure liquid chromatography fractionation of the CHYLO infranate proteins identified the critical protein as transthyretin (TTR), which binds retinol-binding protein and complexes thyroxine and retinol. Addition of TTR alone, with lipid emulsion, or with respun CHYLO to human differentiated adipocytes had little effect on C3 and ASP production. By contrast, when transthyretin was added to CHYLO, C3 and ASP production were substantially enhanced up to 75- and 7. 5-fold respectively, compared with the effect of native CHYLO alone. Finally, a polyclonal antibody against TTR could inhibit stimulation of C3 and ASP production by CHYLO (by 98 and 100%, respectively) and by CHYLO infranate proteins (by 99 and 94%, respectively). We hypothesize that TTR mediates the transfer of the active components from CHYLO to adipocytes, which then stimulates increased C3 and ASP production. Thus the CHYLO provides the physiologic trigger of the ASP pathway.
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Affiliation(s)
- T Scantlebury
- Mike Rosenbloom Laboratory for Cardiovascular Research, McGill University Health Center, McGill University, Montreal, Quebec H3A 1A1, Canada
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41
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Villarroya F. Differential effects of retinoic acid on white and brown adipose tissues. An unexpected role for vitamin A derivatives on energy balance. Ann N Y Acad Sci 1998; 839:190-5. [PMID: 9629149 DOI: 10.1111/j.1749-6632.1998.tb10757.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- F Villarroya
- Department of Biochemistry and Molecular Biology, University of Barcelona, Spain
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Abstract
Adipose tissue is second only to liver as a retinol depot. Retinol is stored there is part as retinyl esters. In cultured mouse adipocytes, a hormone-sensitive lipase hydrolyzes these esters upon cAMP stimulation, with free retinol being released into the medium.
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Affiliation(s)
- G Wolf
- Department of Nutritional Sciences, University of California, Berkeley 94720-3104, USA
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43
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Wei S, Lai K, Patel S, Piantedosi R, Shen H, Colantuoni V, Kraemer FB, Blaner WS. Retinyl ester hydrolysis and retinol efflux from BFC-1beta adipocytes. J Biol Chem 1997; 272:14159-65. [PMID: 9162045 DOI: 10.1074/jbc.272.22.14159] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Adipose tissue is an important storage depot for retinol, but there are no data regarding retinol mobilization from adipose stores. To address this, dibutyryl cAMP was provided to murine BFC-1beta adipocytes and its effects on retinol efflux assessed. High performance liquid chromatography analysis of retinol and retinyl esters in adipocytes and media indicated that cAMP stimulated, in a time- and dose-dependent manner, retinol accumulation in the culture media and decreased cellular retinyl ester concentrations. Study of adipocyte retinol-binding protein synthesis and secretion indicated that cAMP-stimulated retinol efflux into the media did not result from increased retinol-retinol-binding protein secretion but was dependent on the presence of fetal bovine serum in the culture media. Since our data suggested that retinyl esters can be hydrolyzed by a cAMP-dependent enzyme like hormone-sensitive lipase (HSL), in separate studies, we purified a HSL-containing fraction from BFC-1beta adipocytes and demonstrated that it catalyzed retinyl palmitate hydrolysis. Homogenates of Chinese hamster ovary cells overexpressing HSL catalyzed retinyl palmitate hydrolysis in a time-, protein-, and substrate-dependent manner, with an apparent Km for retinyl palmitate of 161 microM, whereas homogenates from control Chinese hamster ovary cells did not.
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Affiliation(s)
- S Wei
- Institute of Human Nutrition, Columbia University, New York, New York 10032, USA
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44
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Kurlandsky SB, Gamble MV, Ramakrishnan R, Blaner WS. Plasma delivery of retinoic acid to tissues in the rat. J Biol Chem 1995; 270:17850-7. [PMID: 7629087 DOI: 10.1074/jbc.270.30.17850] [Citation(s) in RCA: 174] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
All-trans-retinoic acid (RA) activates ligand-dependent transcription factors that regulate retinoid-responsive gene expression. It is assumed that all-trans-RA is formed within cells through in situ oxidation of retinol derived from the circulation. However, the circulation contains low levels of all-trans-RA (approximately 0.2-0.7% of that of plasma retinol). Our studies investigated the extent to which plasma all-trans-RA contributes to tissue pools of this retinoid and explored factors responsible for regulating its uptake by tissues and cells. Rats were continuously infused, to steady state, with all-trans-[3H]RA. From measures of specific activities of all-trans-[3H]RA at steady state, we determined that the preponderance of all-trans-RA in brain and liver was derived from the circulation. For six other tissues, approximately 10-30% of the retinoid was derived from the circulation, but pancreas and testis derived very little from the circulating pool. In other studies, we showed that retinoid nutritional status influences clearance of a bolus dose of all-trans-RA and that neither the rate of cellular all-trans-RA uptake nor its intracellular half-life is influenced by cellular lipid levels. Taken together, our data indicate that plasma all-trans-RA contributes to tissue pools of this retinoid and that specific and physiologically responsive cellular processes mediate its uptake.
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Affiliation(s)
- S B Kurlandsky
- Institute of Human Nutrition, Columbia University, New York, New York 10032, USA
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45
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Okuno M, Caraveo VE, Goodman DS, Blaner WS. Regulation of adipocyte gene expression by retinoic acid and hormones: effects on the gene encoding cellular retinol-binding protein. J Lipid Res 1995. [DOI: 10.1016/s0022-2275(20)39762-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Safonova I, Darimont C, Amri EZ, Grimaldi P, Ailhaud G, Reichert U, Shroot B. Retinoids are positive effectors of adipose cell differentiation. Mol Cell Endocrinol 1994; 104:201-11. [PMID: 7988747 DOI: 10.1016/0303-7207(94)90123-6] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Retinoids, especially all-trans retinoic acid (t-RA), have been reported in the last decade to inhibit the differentiation of preadipose cells. In those studies, however, the concentrations of t-RA were supraphysiological (0.1-10 microM range). In contrast we show that, when present at concentrations below or close to the Kd values of retinoic acid receptors, retinoids behave as potent adipogenic hormones (1 pM to 10 nM range). As shown by the use of specific ligands for each RAR subtype, these positive effects on adipose differentiation involve in particular the RAR alpha subtype, and have been observed in Ob17 cells exposed to serum-supplemented or serum-free medium, and in rat preadipocytes exposed to serum-free medium. Among the two classes of retinoid acid receptors (RARs) and retinoid X receptors (RXRs), RAR alpha, RAR gamma, RXR alpha and RXR beta mRNAs could be detected in growing adipoblasts and were found to be increased in committed preadipocytes and differentiated cells upon retinoid treatment. Like other adipogenic hormones, retinoids were only effective in the terminal differentiation process leading from preadipocytes to adipocytes.
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Affiliation(s)
- I Safonova
- Centre de Biochimie (UMR 134 CNRS), Université de Nice-Sophia Antipolis, Faculté des Sciences, France
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47
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Blaner W, Obunike J, Kurlandsky S, al-Haideri M, Piantedosi R, Deckelbaum R, Goldberg I. Lipoprotein lipase hydrolysis of retinyl ester. Possible implications for retinoid uptake by cells. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(19)89425-5] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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48
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Kamei Y, Kawada T, Mizukami J, Sugimoto E. The prevention of adipose differentiation of 3T3-L1 cells caused by retinoic acid is elicited through retinoic acid receptor alpha. Life Sci 1994; 55:PL307-12. [PMID: 7934625 DOI: 10.1016/0024-3205(94)90073-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Retinoids, especially all-trans retinoic acid (RA), have been shown to inhibit the differentiation of preadipose cells. It is important to human health, especially to obesity, that the regulatory system for the differentiation of adipocytes is well defined. Previously, we have shown that retinoic acid receptor (RAR) gamma 2 gene expression is up-regulated by RA in 3T3-L1 preadipose cells. In this study, the RAR system was dissected and the RA-regulated function in 3T3-L1 cells was assigned to one given receptor. We used three synthetic retinoids; (1) Ro 41-5253, a selective RAR alpha antagonist, (2) Ch 55, an RAR alpha, beta and gamma agonist, and (3) Am 80, an RAR alpha and beta agonist, which has less affinity to RAR gamma. Ro 41-5253 reverted RA-induced inhibition of the differentiation of 3T3-L1 cells. However, there was no significant reversion in RA-induced RAR gamma mRNA level by treatment with Ro 41-5253. In the case of RAR agonists, both Am 80 and Ch 55 strongly inhibited the differentiation of 3T3-L1 cells. However, Am 80 weakly increased RAR gamma mRNA content less than did Ch 55. These findings suggest, that RAR alpha is involved in the prevention of adipose differentiation by RA in 3T3-L1 cells. Moreover, there seems no causal relationship between the prevention of adipose differentiation by RA and the up-regulation of RAR gamma 2 gene expression by RA in 3T3-L1 cells. We have shown the functional heterogeneity of RA action through different RARs in 3T3-L1 cells.
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Affiliation(s)
- Y Kamei
- Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, Japan
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49
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Sasaki A, Sivaram P, Goldberg IJ. Lipoprotein lipase binding to adipocytes: evidence for the presence of a heparin-sensitive binding protein. THE AMERICAN JOURNAL OF PHYSIOLOGY 1993; 265:E880-8. [PMID: 8279543 DOI: 10.1152/ajpendo.1993.265.6.e880] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Lipoprotein lipase (LPL) is synthesized by adipocytes, associated with the cell surface, and released from the cells when they are treated with heparin. Release of LPL from the adipocyte is required for LPL to migrate to its physiological site of action on the luminal surface of capillary endothelial cells. To better understand this process, we studied the interaction of LPL with adipocyte cell membrane proteins. With the use of a ligand blot method, LPL specifically bound to a heparin-releasable, 116-kDa protein on mouse-derived brown fat adipose cell (BFC-1 beta) and rat adipocyte membranes. A 116-kDa cell surface protein was metabolically labeled with [35S]methionine and bound to LPL-Sepharose. This suggested that the LPL-binding protein was synthesized by the cells. When BFC-1 beta were treated with heparin to eliminate heparin-sensitive cell surface binding sites, LPL binding to the cells decreased and release of newly synthesized LPL activity increased. 125I-labeled LPL binding to control cells was reduced (> 70%) by a 50-fold excess of unlabeled LPL. The residual LPL binding to heparin-treated cells was, however, not decreased by the addition of unlabeled LPL. These data imply that specific adipocyte surface LPL binding involves heparin-sensitive sites. We hypothesize that the heparin-releasable, 116-kDa LPL-binding protein mediates specific LPL binding to adipocytes and that LPL activity within adipose tissue is regulated, in part, by the interaction of LPL with this binding protein.
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Affiliation(s)
- A Sasaki
- Department of Medicine and Specialized Center of Research in Arteriosclerosis, Columbia University College of Physicians and Surgeons, New York, New York 10032
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Hernandez A, Garcia-Jimenez C, Santisteban P, Obregon MJ. Regulation of malic-enzyme-gene expression by cAMP and retinoic acid in differentiating brown adipocytes. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 215:285-90. [PMID: 8393790 DOI: 10.1111/j.1432-1033.1993.tb18033.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Brown adipose tissue (BAT) is composed of highly specialized cells, whose main function is to produce heat under adrenergic stimulation, uncoupling oxidative phosphorylation. For this function, lipogenesis must be accurately regulated. Malic enzyme has a central role in lipogenesis and is strongly expressed in brown adipocytes. In this work, we study the modulation by adrenergic stimuli, cAMP effectors and retinoic acid on the induction produced by insulin and 3,5,3'-triiodothyronine on malic-enzyme-gene expression. Primary cultures of differentiating brown adipocytes have been used. The results obtained demonstrate that physiological doses of norepinephrine do not modify malic-enzyme mRNA levels when acting alone, but considerably reduce the induction produced by insulin, 3,5,3'-triiodothyronine or both together. Other cAMP inducers such as glucagon, forskolin or 8-bromo-cAMP, greatly inhibit both, basal and 3,5,3'-triiodothyronine-induced malic-enzyme-gene gene expression. Retinoic acid abolishes basal and also inhibits 3,5,3'-triiodothyronine-induced malic-enzyme-gene expression.
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Affiliation(s)
- A Hernandez
- Instituto de Investigaciones Biomédicas, C. S. I. C., Madrid, Spain
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