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Iyer DR, Venkatraman J, Tanguy E, Vitale N, Mahapatra NR. Chromogranin A and its derived peptides: potential regulators of cholesterol homeostasis. Cell Mol Life Sci 2023; 80:271. [PMID: 37642733 PMCID: PMC11072126 DOI: 10.1007/s00018-023-04908-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 08/02/2023] [Accepted: 08/03/2023] [Indexed: 08/31/2023]
Abstract
Chromogranin A (CHGA), a member of the granin family of proteins, has been an attractive therapeutic target and candidate biomarker for several cardiovascular, neurological, and inflammatory disorders. The prominence of CHGA stems from the pleiotropic roles of several bioactive peptides (e.g., catestatin, pancreastatin, vasostatins) generated by its proteolytic cleavage and by their wide anatomical distribution. These peptides are emerging as novel modulators of cardiometabolic diseases that are often linked to high blood cholesterol levels. However, their impact on cholesterol homeostasis is poorly understood. The dynamic nature of cholesterol and its multitudinous roles in almost every aspect of normal body function makes it an integral component of metabolic physiology. A tightly regulated coordination of cholesterol homeostasis is imperative for proper functioning of cellular and metabolic processes. The deregulation of cholesterol levels can result in several pathophysiological states. Although studies till date suggest regulatory roles for CHGA and its derived peptides on cholesterol levels, the mechanisms by which this is achieved still remain unclear. This review aims to aggregate and consolidate the available evidence linking CHGA with cholesterol homeostasis in health and disease. In addition, we also look at common molecular regulatory factors (viz., transcription factors and microRNAs) which could govern the expression of CHGA and genes involved in cholesterol homeostasis under basal and pathological conditions. In order to gain further insights into the pathways mediating cholesterol regulation by CHGA/its derived peptides, a few prospective signaling pathways are explored, which could act as primers for future studies.
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Affiliation(s)
- Dhanya R Iyer
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Janani Venkatraman
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Emeline Tanguy
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, 5 Rue Blaise Pascal, 67000, Strasbourg, France
| | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, 5 Rue Blaise Pascal, 67000, Strasbourg, France.
| | - Nitish R Mahapatra
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600036, India.
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Okuno Y, Fukuhara A, Otsuki M, Shimomura I. ARMC5-CUL3 E3 ligase targets full-length SREBF in adrenocortical tumor. JCI Insight 2022; 7:151390. [PMID: 35862218 PMCID: PMC9462479 DOI: 10.1172/jci.insight.151390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 07/18/2022] [Indexed: 11/23/2022] Open
Abstract
Inactivating mutations of ARMC5 are responsible for the development of bilateral macronodular adrenal hyperplasia (BMAH). Although ARMC5 inhibits adrenocortical tumor growth and is considered a tumor-suppressor gene, its molecular function is poorly understood. In this study, through biochemical purification using SREBF (SREBP) as bait, we identified the interaction between SREBF and ARMC5 through its Armadillo repeat. We also found that ARMC5 interacted with CUL3 through its BTB domain and underwent self-ubiquitination. ARMC5 colocalized with SREBF1 in the cytosol and induced proteasome-dependent degradation of full-length SREBF through ubiquitination. Introduction of missense mutations in Armadillo repeat of ARMC5 attenuated the interaction between SREBF, and introduction of mutations found in BMAH completely abolished its ability to degrade full-length SREBF. In H295R adrenocortical cells, silencing of ARMC5 increased full-length SREBFs and upregulated SREBF2 target genes. siARMC5-mediated cell growth was abrogated by simultaneous knockdown of SREBF2 in H295R cells. Our results demonstrate that ARMC5 was a substrate adaptor protein between full-length SREBF and CUL3-based E3 ligase, and they suggest the involvement of the SREBF pathway in the development of BMAH.
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Affiliation(s)
- Yosuke Okuno
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Atsunori Fukuhara
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Michio Otsuki
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Iichiro Shimomura
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine, Suita, Japan
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3
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Karimi N, Karami Tehrani FS. Expression of SR-B1 receptor in breast cancer cell lines, MDAMB-468 and MCF-7: Effect on cell proliferation and apoptosis. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2021; 24:1069-1077. [PMID: 34804424 PMCID: PMC8591767 DOI: 10.22038/ijbms.2021.56752.12674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 07/12/2021] [Indexed: 12/21/2022]
Abstract
OBJECTIVES High-density lipoprotein (HDL) is necessary for proliferation of several cells. The growth of many kinds of cells, such as breast cancer cells (BCC) is motivated by HDL. Cellular uptake of cholesterol from HDL which increases cell growth is facilitated by scavenger receptors of the B class (SR-BI). The proliferative effect of HDL might be mediated by this receptor. It is also believed that HDL has an anti-apoptotic effect on various cell types and promotes cell growth. This study was designed to investigate SR-BI expression, proliferation and apoptotic effect of HDL on human BCC lines, MCF-7 and MDA-MB-468. MATERIALS AND METHODS Real-time-PCR method was used to evaluate expression of SR-BI, and cholesterol concentration was measured using a cholesterol assay kits (Pars AZ moon, Karaj, Iran). Cell viability was assessed using the MTT test. To identify cell apoptosis, the annexin V-FITC staining test and caspase-9 activity assay were applied. RESULTS Treatment of both cell lines (MCF-7, MDA-MB-468) with HDL results in augmentation of SR-BI mRNA expression and also elevation of the intracellular cholesterol (P<0.01). HDL induced cell proliferation, cell cycle progression, and prevented activation of caspase-9 (P<0.05). We also demonstrated that inhibition of SR-B1 by BLT-1 could reduce cell proliferation, and induction of SR-B1 receptor by quercetin increased HDL-induced proliferation in both cell lines (P<0.05). CONCLUSION It can be concluded that alteration in HDL levels by SR-B1 activator (Quercetin) or inhibitor (BLT-1) may affect BCC growth and apoptosis induction.
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Affiliation(s)
- Neamat Karimi
- Department of Clinical Biochemistry, Cancer Research Laboratory, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Fatemeh Soghra Karami Tehrani
- Department of Clinical Biochemistry, Cancer Research Laboratory, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
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Revilla G, Cedó L, Tondo M, Moral A, Pérez JI, Corcoy R, Lerma E, Fuste V, Reddy ST, Blanco-Vaca F, Mato E, Escolà-Gil JC. LDL, HDL and endocrine-related cancer: From pathogenic mechanisms to therapies. Semin Cancer Biol 2020; 73:134-157. [PMID: 33249202 DOI: 10.1016/j.semcancer.2020.11.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 10/19/2020] [Accepted: 11/16/2020] [Indexed: 02/07/2023]
Abstract
Cholesterol is essential for a variety of functions in endocrine-related cells, including hormone and steroid production. We have reviewed the progress to date in research on the role of the main cholesterol-containing lipoproteins; low-density lipoprotein (LDL) and high-density lipoprotein (HDL), and their impact on intracellular cholesterol homeostasis and carcinogenic pathways in endocrine-related cancers. Neither LDL-cholesterol (LDL-C) nor HDL-cholesterol (HDL-C) was consistently associated with endocrine-related cancer risk. However, preclinical studies showed that LDL receptor plays a critical role in endocrine-related tumor cells, mainly by enhancing circulating LDL-C uptake and modulating tumorigenic signaling pathways. Although scavenger receptor type BI-mediated uptake of HDL could enhance cell proliferation in breast, prostate, and ovarian cancer, these effects may be counteracted by the antioxidant and anti-inflammatory properties of HDL. Moreover, 27-hydroxycholesterol a metabolite of cholesterol promotes tumorigenic processes in breast and epithelial thyroid cancer. Furthermore, statins have been reported to reduce the incidence of breast, prostate, pancreatic, and ovarian cancer in large clinical trials, in part because of their ability to lower cholesterol synthesis. Overall, cholesterol homeostasis deregulation in endocrine-related cancers offers new therapeutic opportunities, but more mechanistic studies are needed to translate the preclinical findings into clinical therapies.
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Affiliation(s)
- Giovanna Revilla
- Institut de Recerca de l'Hospital de la Santa Creu i Sant Pau, Institut d'Investigacions Biomèdiques (IIB) Sant Pau, C/ Sant Quintí 77, 08041 Barcelona Spain; Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, C/ Antoni M. Claret 167, 08025 Barcelona, Spain
| | - Lídia Cedó
- Institut de Recerca de l'Hospital de la Santa Creu i Sant Pau, Institut d'Investigacions Biomèdiques (IIB) Sant Pau, C/ Sant Quintí 77, 08041 Barcelona Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), C/ Monforte de Lemos 3-5, 28029 Madrid, Spain
| | - Mireia Tondo
- Institut de Recerca de l'Hospital de la Santa Creu i Sant Pau, Institut d'Investigacions Biomèdiques (IIB) Sant Pau, C/ Sant Quintí 77, 08041 Barcelona Spain; Servei de Bioquímica, Hospital de la Santa Creu i Sant Pau, C/ Sant Quintí 89, 08041 Barcelona, Spain
| | - Antonio Moral
- Department of General Surgery, Hospital de la Santa Creu i Sant Pau, C/ Sant Quintí 89, 08041 Barcelona, Spain; Departament de Medicina, Universitat Autònoma de Barcelona, C/ Antoni M. Claret 167, 08025 Barcelona, Spain
| | - José Ignacio Pérez
- Department of General Surgery, Hospital de la Santa Creu i Sant Pau, C/ Sant Quintí 89, 08041 Barcelona, Spain
| | - Rosa Corcoy
- Departament de Medicina, Universitat Autònoma de Barcelona, C/ Antoni M. Claret 167, 08025 Barcelona, Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/ Monforte de Lemos 3-5, 28029 Madrid, Spain; Department of Endocrinology and Nutrition, Hospital de la Santa Creu i Sant Pau, C/ Sant Quintí 89, 08041 Barcelona, Spain
| | - Enrique Lerma
- Institut de Recerca de l'Hospital de la Santa Creu i Sant Pau, Institut d'Investigacions Biomèdiques (IIB) Sant Pau, C/ Sant Quintí 77, 08041 Barcelona Spain; Department of Anatomic Pathology, Hospital de la Santa Creu i Sant Pau, C/ Sant Quintí 89, 08041 Barcelona, Spain
| | - Victoria Fuste
- Institut de Recerca de l'Hospital de la Santa Creu i Sant Pau, Institut d'Investigacions Biomèdiques (IIB) Sant Pau, C/ Sant Quintí 77, 08041 Barcelona Spain; Department of Anatomic Pathology, Hospital de la Santa Creu i Sant Pau, C/ Sant Quintí 89, 08041 Barcelona, Spain
| | - Srivinasa T Reddy
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095-1736, USA
| | - Francisco Blanco-Vaca
- Institut de Recerca de l'Hospital de la Santa Creu i Sant Pau, Institut d'Investigacions Biomèdiques (IIB) Sant Pau, C/ Sant Quintí 77, 08041 Barcelona Spain; Servei de Bioquímica, Hospital de la Santa Creu i Sant Pau, C/ Sant Quintí 89, 08041 Barcelona, Spain.
| | - Eugènia Mato
- Institut de Recerca de l'Hospital de la Santa Creu i Sant Pau, Institut d'Investigacions Biomèdiques (IIB) Sant Pau, C/ Sant Quintí 77, 08041 Barcelona Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/ Monforte de Lemos 3-5, 28029 Madrid, Spain.
| | - Joan Carles Escolà-Gil
- Institut de Recerca de l'Hospital de la Santa Creu i Sant Pau, Institut d'Investigacions Biomèdiques (IIB) Sant Pau, C/ Sant Quintí 77, 08041 Barcelona Spain.
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Prenatal caffeine ingestion induces long-term alterations in scavenger receptor class B type I expression and glucocorticoid synthesis in adult male offspring rat adrenals. Food Chem Toxicol 2018; 120:24-31. [PMID: 29958987 DOI: 10.1016/j.fct.2018.06.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 06/07/2018] [Accepted: 06/25/2018] [Indexed: 11/21/2022]
Abstract
Caffeine is contained within many drinks and food that are consumed daily. Prenatal caffeine ingestion (PCI) is a risk factor for intrauterine growth retardation (IUGR). We previously observed that PCI inhibits scavenger receptor class B type I (SR-BI)-mediated cholesterol uptake in fetal adrenals, subsequently decreasing glucocorticoid synthesis and inducing IUGR. In the present study, we aimed to investigate the long-term effects of PCI on adrenal glucocorticoid synthesis in adult male offspring rats. After establishing the PCI-induced IUGR, adult male offspring was injected intraperitoneally with 5 mg/kg·d lipopolysaccharide (LPS) for 2 days to induce acute stress. We observed persistent inhibition of SR-BI expression in PCI adrenals before and after stress. Compared with the controls, the PCI offspring had higher corticosterone concentrations after stress. The serum cholesterol concentration was stable without intergroup differences before and after stress. The cholesterol concentration in PCI adrenals showed a higher decrease rate than that of the control after stress. In summary, PCI induced long-term alterations in SR-BI expression and glucocorticoid synthesis in adult male offspring rat adrenals. Cholesterol has to be over-consumed in PCI adrenals against acute stress. This study provides an experimental basis to explain the susceptibility of IUGR offspring to metabolic diseases in adults.
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Shen WJ, Azhar S, Kraemer FB. SR-B1: A Unique Multifunctional Receptor for Cholesterol Influx and Efflux. Annu Rev Physiol 2017; 80:95-116. [PMID: 29125794 DOI: 10.1146/annurev-physiol-021317-121550] [Citation(s) in RCA: 221] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The scavenger receptor, class B type 1 (SR-B1), is a multiligand membrane receptor protein that functions as a physiologically relevant high-density lipoprotein (HDL) receptor whose primary role is to mediate selective uptake or influx of HDL-derived cholesteryl esters into cells and tissues. SR-B1 also facilitates the efflux of cholesterol from peripheral tissues, including macrophages, back to liver. As a regulator of plasma membrane cholesterol content, SR-B1 promotes the uptake of lipid soluble vitamins as well as viral entry into host cells. These collective functions of SR-B1 ultimately affect programmed cell death, female fertility, platelet function, vasculature inflammation, and diet-induced atherosclerosis and myocardial infarction. SR-B1 has also been identified as a potential marker for cancer diagnosis and prognosis. Finally, the SR-B1-linked selective HDL-cholesteryl ester uptake pathway is now being evaluated as a gateway for the delivery of therapeutic and diagnostic agents. In this review, we focus on the regulation and functional significance of SR-B1 in mediating cholesterol movement into and out of cells.
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Affiliation(s)
- Wen-Jun Shen
- Division of Endocrinology, Gerontology and Metabolism, Stanford University School of Medicine, Stanford, California 94305; .,VA Palo Alto Health Care System, Palo Alto, California 94304
| | - Salman Azhar
- Division of Endocrinology, Gerontology and Metabolism, Stanford University School of Medicine, Stanford, California 94305; .,VA Palo Alto Health Care System, Palo Alto, California 94304
| | - Fredric B Kraemer
- Division of Endocrinology, Gerontology and Metabolism, Stanford University School of Medicine, Stanford, California 94305; .,VA Palo Alto Health Care System, Palo Alto, California 94304
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Mooberry LK, Sabnis NA, Panchoo M, Nagarajan B, Lacko AG. Targeting the SR-B1 Receptor as a Gateway for Cancer Therapy and Imaging. Front Pharmacol 2016; 7:466. [PMID: 28018216 PMCID: PMC5156841 DOI: 10.3389/fphar.2016.00466] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 11/16/2016] [Indexed: 01/25/2023] Open
Abstract
Malignant tumors display remarkable heterogeneity to the extent that even at the same tissue site different types of cells with varying genetic background may be found. In contrast, a relatively consistent marker the scavenger receptor type B1 (SR-B1) has been found to be consistently overexpressed by most tumor cells. Scavenger Receptor Class B Type I (SR-BI) is a high density lipoprotein (HDL) receptor that facilitates the uptake of cholesterol esters from circulating lipoproteins. Additional findings suggest a critical role for SR-BI in cholesterol metabolism, signaling, motility, and proliferation of cancer cells and thus a potential major impact in carcinogenesis and metastasis. Recent findings indicate that the level of SR-BI expression correlate with aggressiveness and poor survival in breast and prostate cancer. Moreover, genomic data show that depending on the type of cancer, high or low SR-BI expression may promote poor survival. This review discusses the importance of SR-BI as a diagnostic as well as prognostic indicator of cancer to help elucidate the contributions of this protein to cancer development, progression, and survival. In addition, the SR-B1 receptor has been shown to serve as a potential gateway for the delivery of therapeutic agents when reconstituted high density lipoprotein nanoparticles are used for their transport to cancer cells and tumors. Opportunities for the development of new technologies, particularly in the areas of cancer therapy and tumor imaging are discussed.
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Affiliation(s)
- Linda K. Mooberry
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort WorthTX, USA
| | - Nirupama A. Sabnis
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort WorthTX, USA
| | - Marlyn Panchoo
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort WorthTX, USA
| | - Bhavani Nagarajan
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort WorthTX, USA
| | - Andras G. Lacko
- Institute for Cardiovascular and Metabolic Disease, University of North Texas Health Science Center, Fort WorthTX, USA
- Department of Pediatrics, University of North Texas Health Science Center, Fort WorthTX, USA
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Kim CO, Oh ES, Choi C, Kim Y, Lee S, Kim S, Park MS. Pharmacokinetics, pharmacodynamics and safety of CKD-519, a CETP inhibitor, in healthy subjects. Drug Des Devel Ther 2016; 10:3763-3770. [PMID: 27895466 PMCID: PMC5117885 DOI: 10.2147/dddt.s120387] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
CKD-519 is a selective and potent cholesteryl ester transfer protein (CETP) inhibitor being developed for the treatment of dyslipidemia to raise high-density lipoprotein cholesterol. We investigated the safety, tolerability, pharmacokinetics, and pharmacodynamics of single doses of CKD-519 in healthy adult subjects. A randomized, double-blinded, placebo-controlled, single ascending dose study was performed. Eight healthy subjects were enrolled in each CKD-519 dose group (25, 50, 100, 200, or 400 mg) and randomized to CKD-519 (n=6) or matching placebo (n=2). CKD-519 reached the maximum plasma concentration (Cmax) at 5–6 h post-dose, and had a long terminal half-life ranging between 40–70 h. The area under the plasma concentration–time curve (AUC) and Cmax increased with the dose, however, Cmax and AUC normalized by dose decreased with each incremental dose. CETP activity decreased with dose, and the maximum decrease (63%–83%) was observed at 6–8 h post-dose. A sigmoid Emax model best described the relationship between CKD-519 plasma concentrations and CETP activity with an EC50 of 17.3 ng/mL. Overall, 11 adverse events (AEs) were observed. All AEs were mild or moderate in intensity, and resolved without any complications. There were no clinically significant effects on blood pressure. In conclusion, single doses of CKD-519 up to 400 mg were well tolerated and showed potent inhibition of CETP activity.
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Affiliation(s)
- Choon Ok Kim
- Department of Clinical Pharmacology, Severance Hospital, Yonsei University College of Medicine, Seoul
| | - Eun Sil Oh
- Department of Pharmaceutical Medicines and Regulatory Science, Colleges of Medicine and Pharmacy, Yonsei University, Incheon
| | - Chungam Choi
- Department of Clinical Pharmacology, Severance Hospital, Yonsei University College of Medicine, Seoul
| | - Yeonjoo Kim
- Chong Kun Dang Clinical Research, Chong Kun Dang Pharmaceutical Corp
| | - Sera Lee
- Chong Kun Dang Research Institute, Chong Kun Dang Pharmaceutical Corp
| | - Semi Kim
- Chong Kun Dang Research Institute, Chong Kun Dang Pharmaceutical Corp
| | - Min Soo Park
- Department of Clinical Pharmacology, Severance Hospital, Yonsei University College of Medicine, Seoul; Department of Pediatrics, Yonsei University College of Medicine, Seoul, Republic of Korea
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Hu Z, Li J, Kuang Z, Wang M, Azhar S, Guo Z. Cell-Specific Polymorphism and Hormonal Regulation of DNA Methylation in Scavenger Receptor Class B, Type I. DNA Cell Biol 2016; 35:280-9. [PMID: 26981684 DOI: 10.1089/dna.2015.3185] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The scavenger receptor class B, type I (SR-BI), is a cell-surface glycoprotein that mediates selective uptake of high density lipoprotein (HDL)-derived cholesteryl ester. SR-BI plays an important role in cellular delivery of cholesterol. Both human and rodent SR-BI are expressed most abundantly in the liver parenchymal cells and steroidogenic cells of the adrenal gland and gonads, where the selective pathway exhibits its highest activity. In steroidogenic cells, the expression of SR-BI is regulated by trophic hormones (adrenocorticotropic hormone or gonadotropins luteinizing hormone or follicle-stimulating hormone) in concert with the regulation of steroid hormone production. DNA methylation has been implicated in a large number of biological processes mainly by regulating gene expression. The SR-BI promoter contains one CpG island (CGI) in its promoter and seven CGIs in its intronic regions. Here, we studied the DNA methylation status of SR-BI gene and provide evidence that the DNA methylation is cell specific in this gene promoter as well as in intronic regions. The DNA methylation in the SR-BI promoter is subject to N(6), 2'-O-dibutyryladenosine3':5'-cyclic monophosphate regulation in mouse adrenal Y1 cells and mouse Leydig tumor cells (MLTCs). The seven intron CGIs are methylated differentially in Y1 cells, MLTCs, ovarian granulosa cells, and mouse liver hepa 1-6 cells. Our experiments raised the possibility that DNA methylation participates in hormonal regulation of SR-BI expression in a tissue-specific manner. We further suggest that the cell-specific DNA methylation in SR-BI intronic regions may be associated with specific biological function(s) of these regions, including regulation of gene expression.
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Affiliation(s)
- Zhigang Hu
- 1 Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University , Nanjing, China
| | - Jiaxin Li
- 1 Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University , Nanjing, China
| | - Zhihui Kuang
- 1 Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University , Nanjing, China
| | - Meina Wang
- 1 Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University , Nanjing, China
| | - Salman Azhar
- 2 Geriatric Research, Education and Clinical Center, VA Palo Alto Health Care System, and Stanford University School of Medicine , Palo Alto, California
| | - Zhigang Guo
- 1 Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University , Nanjing, China
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Kroiss M, Plonné D, Kendl S, Schirmer D, Ronchi CL, Schirbel A, Zink M, Lapa C, Klinker H, Fassnacht M, Heinz W, Sbiera S. Association of mitotane with chylomicrons and serum lipoproteins: practical implications for treatment of adrenocortical carcinoma. Eur J Endocrinol 2016; 174:343-53. [PMID: 26671975 DOI: 10.1530/eje-15-0946] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 12/15/2015] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Oral mitotane (o,p'-DDD) is a cornerstone of medical treatment for adrenocortical carcinoma (ACC). AIM Serum mitotane concentrations >14 mg/l are targeted for improved efficacy but not achieved in about half of patients. Here we aimed at a better understanding of intestinal absorption and lipoprotein association of mitotane and metabolites o,p'-dichlorodiphenylacetic acid (o,p'-DDA) and o,p'-dichlorodiphenyldichloroethane (o,p'-DDE). DESIGN Lipoproteins were isolated by ultracentrifugation from the chyle of a 29-year-old patient and serum from additional 14 ACC patients treated with mitotane. HPLC was applied for quantification of mitotane and metabolites. We assessed NCI-H295 cell viability, cortisol production, and expression of endoplasmic reticulum (ER) stress marker genes to study the functional consequences of mitotane binding to lipoproteins. RESULTS Chyle of the index patient contained 197 mg/ml mitotane, 53 mg/ml o,p'-DDA, and 51 mg/l o,p'-DDE. Of the total mitotane in serum, lipoprotein fractions contained 21.7±21.4% (VLDL), 1.9±0.8% (IDL), 8.9±5.5% (LDL1), 18.9±9.6% (LDL2), 10.1±4.0% (LDL3), and 26.3±13.0% (HDL2). Only 12.3±5.5% were in the lipoprotein-depleted fraction. DISCUSSION Mitotane content of lipoproteins directly correlated with their triglyceride and cholesterol content. O,p'-DDE was similarly distributed, but 87.9±4.2% of o,p'-DDA found in the HDL2 and lipoprotein-depleted fractions. Binding of mitotane to human lipoproteins blunted its anti-proliferative and anti-hormonal effects on NCI-H295 cells and reduced ER stress marker gene expression. CONCLUSION Mitotane absorption involves chylomicron binding. High concentrations of o,p'-DDA and o,p'-DDE in chyle suggest intestinal mitotane metabolism. In serum, the majority of mitotane is bound to lipoproteins. In vitro, lipoprotein binding inhibits activity of mitotane suggesting that lipoprotein-free mitotane is the therapeutically active fraction.
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Affiliation(s)
- Matthias Kroiss
- Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany
| | - Dietmar Plonné
- Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany
| | - Sabine Kendl
- Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany
| | - Diana Schirmer
- Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany
| | - Cristina L Ronchi
- Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany
| | - Andreas Schirbel
- Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany
| | - Martina Zink
- Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany
| | - Constantin Lapa
- Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany
| | - Hartwig Klinker
- Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany
| | - Martin Fassnacht
- Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany
| | - Werner Heinz
- Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany
| | - Silviu Sbiera
- Endocrine and Diabetes UnitDepartment of Internal Medicine IInfectiology UnitDepartment of Internal Medicine II, University Hospital Würzburg, Oberdürrbacher Street 6, 97080 Würzburg, GermanyComprehensive Cancer Center MainfrankenUniversity of Würzburg, Würzburg, GermanyDivision of Laboratory MedicineMedical Care Centre of Human Genetics Ulm, Ulm, GermanyDepartment of Nuclear MedicineUniversity Hospital Würzburg, Würzburg, GermanyClinical Chemistry and Laboratory MedicineUniversity Hospital Würzburg, Würzburg, Germany
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11
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Abstract
The adrenal gland is one of the prominent sites for steroid hormone synthesis. Lipoprotein-derived cholesterol esters (CEs) delivered via SR-B1 constitute the dominant source of cholesterol for steroidogenesis, particularly in rodents. Adrenocorticotropic hormone (ACTH) stimulates steroidogenesis through downstream actions on multiple components involved in steroidogenesis. Both acute and chronic ACTH treatments can modulate SR-B1 function, including its transcription, posttranscriptional stability, phosphorylation and dimerization status, as well as the interaction with other protein partners, all of which result in changes in the ability of SR-B1 to mediate HDL-CE uptake and the supply of cholesterol for conversion to steroids. Here, we provide a review of the recent findings on the regulation of adrenal SR-B1 function by ACTH.
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Affiliation(s)
- Wen-Jun Shen
- The Division of Endocrinology, Stanford University, Stanford, CA, USA
- Geriatric Research, Education and Clinical Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Salman Azhar
- The Division of Endocrinology, Stanford University, Stanford, CA, USA
- Geriatric Research, Education and Clinical Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Fredric B. Kraemer
- The Division of Endocrinology, Stanford University, Stanford, CA, USA
- Geriatric Research, Education and Clinical Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
- *Correspondence: Fredric B. Kraemer,
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12
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Wu DM, He Z, Ma LP, Wang LL, Ping J, Wang H. Increased DNA methylation of scavenger receptor class B type I contributes to inhibitory effects of prenatal caffeine ingestion on cholesterol uptake and steroidogenesis in fetal adrenals. Toxicol Appl Pharmacol 2015; 285:89-97. [PMID: 25868845 DOI: 10.1016/j.taap.2015.03.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 03/19/2015] [Accepted: 03/31/2015] [Indexed: 11/18/2022]
Abstract
Steroid hormones synthesized from cholesterol in the fetal adrenal are crucial for fetal development. We have observed the inhibited fetal adrenal corticosterone synthesis and increased intrauterine growth retardation (IUGR) rate in rats under prenatal caffeine ingestion. The aim of this study is to evaluate the effects of prenatal caffeine ingestion on cholesterol supply in fetal adrenal steroidogenesis in rats and explore the underlying epigenetic mechanisms. Pregnant Wistar rats were treated with 60 mg/kg · d caffeine from gestational day (GD) 7 to GD17. Histological changes of fetal adrenals and increased IUGR rates were observed in the caffeine group. There were significantly decreased steroid hormone contents and cholesterol supply in caffeine-treated fetal adrenals. Data from the gene expression array suggested that prenatal caffeine ingestion caused increased expression of genes related to DNA methylation and decreased expression of genes related to cholesterol uptake. The following conjoint analysis of DNA methylation array with these differentially expressed genes suggested that scavenger receptor class B type I (SR-BI) may play an important role in caffeine-induced cholesterol supply deficiency. Moreover, real-time RT-PCR and immunohistochemical detection certified the inhibitory effects of caffeine on both mRNA expression and protein expression of SR-BI in the fetal adrenal. And the increased DNA methylation frequency in the proximal promoter of SR-BI was confirmed by bisulfite-sequencing PCR. In conclusion, prenatal caffeine ingestion can induce DNA hypermethylation of the SR-BI promoter in the rat fetal adrenal. These effects may lead to decreased SR-BI expression and cholesterol uptake, which inhibits steroidogenesis in the fetal adrenal.
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Affiliation(s)
- Dong-Mei Wu
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Zheng He
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Liang-Peng Ma
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Lin-Long Wang
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Jie Ping
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China; Hubei Provincial Key Laboratory of Developmentally Originated Diseases, Wuhan 430071, China; Research Center of Food and Drug Evaluation, Wuhan University, Wuhan 430071, China.
| | - Hui Wang
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China; Hubei Provincial Key Laboratory of Developmentally Originated Diseases, Wuhan 430071, China; Research Center of Food and Drug Evaluation, Wuhan University, Wuhan 430071, China
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13
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Zhao Y, Hoekstra M, Korporaal SJA, Van Berkel TJC, Van Eck M. HDL Receptor Scavenger Receptor BI. Atherosclerosis 2015. [DOI: 10.1002/9781118828533.ch25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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14
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Abstract
The purpose of this article is to review fundamentals in adrenal gland histophysiology. Key findings regarding the important signaling pathways involved in the regulation of steroidogenesis and adrenal growth are summarized. We illustrate how adrenal gland morphology and function are deeply interconnected in which novel signaling pathways (Wnt, Sonic hedgehog, Notch, β-catenin) or ionic channels are required for their integrity. Emphasis is given to exploring the mechanisms and challenges underlying the regulation of proliferation, growth, and functionality. Also addressed is the fact that while it is now well-accepted that steroidogenesis results from an enzymatic shuttle between mitochondria and endoplasmic reticulum, key questions still remain on the various aspects related to cellular uptake and delivery of free cholesterol. The significant progress achieved over the past decade regarding the precise molecular mechanisms by which the two main regulators of adrenal cortex, adrenocorticotropin hormone (ACTH) and angiotensin II act on their receptors is reviewed, including structure-activity relationships and their potential applications. Particular attention has been given to crucial second messengers and how various kinases, phosphatases, and cytoskeleton-associated proteins interact to ensure homeostasis and/or meet physiological demands. References to animal studies are also made in an attempt to unravel associated clinical conditions. Many of the aspects addressed in this article still represent a challenge for future studies, their outcome aimed at providing evidence that the adrenal gland, through its steroid hormones, occupies a central position in many situations where homeostasis is disrupted, thus highlighting the relevance of exploring and understanding how this key organ is regulated. © 2014 American Physiological Society. Compr Physiol 4:889-964, 2014.
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Affiliation(s)
- Nicole Gallo-Payet
- Division of Endocrinology, Department of Medicine, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, and Centre de Recherche Clinique Étienne-Le Bel of the Centre Hospitalier Universitaire de Sherbrooke (CHUS), Sherbrooke, Quebec, Canada
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15
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Niesor EJ. Will Lipidation of ApoA1 through Interaction with ABCA1 at the Intestinal Level Affect the Protective Functions of HDL? BIOLOGY 2015; 4:17-38. [PMID: 25569858 PMCID: PMC4381214 DOI: 10.3390/biology4010017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 12/18/2014] [Indexed: 11/16/2022]
Abstract
The relationship between levels of high-density lipoprotein cholesterol (HDL-C) and cardiovascular (CV) risk is well recognized; however, in recent years, large-scale phase III studies with HDL-C-raising or -mimicking agents have failed to demonstrate a clinical benefit on CV outcomes associated with raising HDL-C, casting doubt on the "HDL hypothesis." This article reviews potential reasons for the observed negative findings with these pharmaceutical compounds, focusing on the paucity of translational models and relevant biomarkers related to HDL metabolism that may have confounded understanding of in vivo mechanisms. A unique function of HDL is its ability to interact with the ATP-binding cassette transporter (ABC) A1 via apolipoprotein (Apo) A1. Only recently, studies have shown that this process may be involved in the intestinal uptake of dietary sterols and antioxidants (vitamin E, lutein and zeaxanthin) at the basolateral surface of enterocytes. This parameter should be assessed for HDL-raising drugs in addition to the more documented reverse cholesterol transport (RCT) from peripheral tissues to the liver. Indeed, a single mechanism involving the same interaction between ApoA1 and ABCA1 may encompass two HDL functions previously considered as separate: antioxidant through the intestinal uptake of antioxidants and RCT through cholesterol efflux from loaded cells such as macrophages.
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Affiliation(s)
- Eric J Niesor
- F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland.
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16
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Out C, Dikkers A, Laskewitz A, Boverhof R, van der Ley C, Kema IP, Wolters H, Havinga R, Verkade HJ, Kuipers F, Tietge UJF, Groen AK. Prednisolone increases enterohepatic cycling of bile acids by induction of Asbt and promotes reverse cholesterol transport. J Hepatol 2014; 61:351-7. [PMID: 24681341 DOI: 10.1016/j.jhep.2014.03.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 02/21/2014] [Accepted: 03/19/2014] [Indexed: 12/04/2022]
Abstract
BACKGROUND & AIMS Glucocorticoids, produced by the adrenal gland under control of the hypothalamic-pituitary-adrenal axis, exert their metabolic actions largely via activation of the glucocorticoid receptor (GR). Synthetic glucocorticoids are widely used as anti-inflammatory and immunosuppressive drugs but their application is hampered by adverse metabolic effects. Recently, it has been shown that GR may regulate several genes involved in murine bile acid (BA) and cholesterol metabolism, yet the physiological relevance hereof is controversial. The aim of this study is to provide a mechanistic basis for effects of prednisolone on BA and cholesterol homeostasis in mice. METHODS Male BALB/c mice were treated with prednisolone (12.5mg/kg/day) for 7days by subcutaneous implantation of slow-release pellets, followed by extensive metabolic profiling. RESULTS Sustained prednisolone treatment induced the expression of the apical sodium-dependent bile acid transporter (Asbt) in the ileum, which stimulated BA absorption. This resulted in elevated plasma BA levels and enhanced biliary BA secretion. Concomitantly, both biliary cholesterol and phospholipid secretion rates were increased. Enhanced BA reabsorption suppressed hepatic BA synthesis, as evident from hepatic gene expression, reduced plasma C4 levels and reduced fecal BA loss. Plasma HDL cholesterol levels were elevated in prednisolone-treated mice, which likely contributed to the stimulated flux of cholesterol from intraperitoneally injected macrophage foam cells into feces. CONCLUSIONS Sustained prednisolone treatment increases enterohepatic recycling of BA, leading to elevated plasma levels and reduced synthesis in the absence of cholestasis. Under these conditions, prednisolone promotes macrophage-derived reverse cholesterol transport.
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Affiliation(s)
- Carolien Out
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands.
| | - Arne Dikkers
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands
| | - Anke Laskewitz
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands
| | - Renze Boverhof
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands
| | | | - Ido P Kema
- Department of Laboratory Medicine, Groningen, The Netherlands
| | - Henk Wolters
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands
| | - Rick Havinga
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands
| | - Henkjan J Verkade
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands
| | - Folkert Kuipers
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands; Department of Laboratory Medicine, Groningen, The Netherlands
| | - Uwe J F Tietge
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands
| | - Albert K Groen
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands; Department of Laboratory Medicine, Groningen, The Netherlands
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17
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Swierczynska MM, Lamounier-Zepter V, Bornstein SR, Eaton S. Lipoproteins and Hedgehog signalling--possible implications for the adrenal gland function. Eur J Clin Invest 2013; 43:1178-83. [PMID: 23992253 DOI: 10.1111/eci.12145] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 07/27/2013] [Indexed: 12/20/2022]
Abstract
BACKGROUND Metabolic syndrome is a common metabolic disorder that is associated with an increased risk of type 2 diabetes and cardiovascular diseases. Disturbances in adrenal steroid hormone production significantly contribute to the development of this disorder. Therefore, it is extremely important to fully understand the mechanisms governing adrenal gland function, both in physiological and pathological conditions. RESULTS Recently, Sonic hedgehog has emerged as an important regulator of adrenal development, with a possible role in adult gland homeostasis. Recent work of our group shows that lipoproteins are important regulators of Hedgehog signaling; they act as carriers for the spread of Hedgehog proteins, but also contain lipid(s) that inhibit the pathway. CONCLUSIONS We propose that lipoproteins may affect Sonic hedgehog signaling in the adult adrenal gland at multiple levels. Understanding the interplay between lipoprotein metabolism and adrenal Hedgehog signaling may improve our understanding of how adrenal gland disorders contribute to the metabolic syndrome.
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Affiliation(s)
- Marta M Swierczynska
- Department of Internal Medicine III, University Hospital Carl Gustav Carus, Dresden, Germany; Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
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18
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Mechanistic profiling of the cAMP-dependent steroidogenic pathway in the H295R endocrine disrupter screening system: new endpoints for toxicity testing. Toxicol Lett 2011; 208:174-84. [PMID: 22079614 DOI: 10.1016/j.toxlet.2011.10.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 10/12/2011] [Accepted: 10/13/2011] [Indexed: 01/26/2023]
Abstract
The need for implementation of effects on steroid synthesis and hormone processing in screening batteries of endocrine disruptive compounds is widely acknowledged. In this perspective, hormone profiling in the H295R adrenocortical cell system is extensively examined and recently OECD validated (TG 456) as a replacement of the minced testis assay. To further elucidate the complete mechanisms and endocrine responsiveness of this cell system, microarray-based gene expression profiling of the cAMP response pathway, one of the major pathways in steroidogenesis regulation, was examined in H295R cells. Next to the steroid synthesis pathway, a broader lipid metabolic pathway, including cholesterol uptake/biosynthesis, hormone metabolization and many hormone and nuclear receptors, are sensitive towards cAMP stimulation in this cell system. Moreover, these pathways were clearly dose and time responsive, indicating early regulation (10 h) of cholesterol uptake and mobilization genes and later expression (24-48 h) of cholesterol biosynthesis and steroid synthesis. Transcription network analysis suggested several important transcription factors that could be involved in regulation of the steroid hormone pathway, of which HNF4α, a broader lipid metabolism related transcription factor, might indicate some new transcription regulation patterns in this cell line. Overall we can conclude that the time dependent gene expression patterns of the strongly coordinated cholesterol supply and steroidogenesis pathways in the H295R cell system seem to reflect well the in vivo ACTH/cAMP signalling cascade in adrenal cells. Moreover, the completeness of the steroidogenic related pathways in terms of gene expression sensitivity, indicates the H295R cell line as a promising cell line in omics-based endocrine disruption screening.
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19
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Nieland TJ, Xu S, Penman M, Krieger M. Negatively cooperative binding of high-density lipoprotein to the HDL receptor SR-BI. Biochemistry 2011; 50:1818-30. [PMID: 21254782 PMCID: PMC3065119 DOI: 10.1021/bi101657j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Scavenger receptor class B, type I (SR-BI), is a high-density lipoprotein (HDL) receptor, which also binds low-density lipoprotein (LDL), and mediates the cellular selective uptake of cholesteryl esters from lipoproteins. SR-BI also is a coreceptor for hepatitis C virus and a signaling receptor that regulates cell metabolism. Many investigators have reported that lipoproteins bind to SR-BI via a single class of independent (not interacting), high-affinity binding sites (one site model). We have reinvestigated the ligand concentration dependence of (125)I-HDL binding to SR-BI and SR-BI-mediated specific uptake of [(3)H]CE from [(3)H]CE-HDL using an expanded range of ligand concentrations (<1 μg of protein/mL, lower than previously reported). Scatchard and nonlinear least-squares model fitting analyses of the binding and uptake data were both inconsistent with a single class of independent binding sites binding univalent lipoprotein ligands. The data are best fit by models in which SR-BI has either two independent classes of binding sites or one class of sites exhibiting negative cooperativity due to either classic allostery or ensemble effects ("lattice model"). Similar results were observed for LDL. Application of the "infinite dilution" dissociation rate method established that the binding of (125)I-HDL to SR-BI at 4 °C exhibits negative cooperativity. The unexpected complexity of the interactions of lipoproteins with SR-BI should be taken into account when interpreting the results of experiments that explore the mechanism(s) by which SR-BI mediates ligand binding, lipid transport, and cell signaling.
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Affiliation(s)
- Thomas J.F. Nieland
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, MA 02139
- Broad Institute of Harvard and MIT, 7 Cambridge Center, Cambridge, MA 02142
| | - Shangzhe Xu
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, MA 02139
| | - Marsha Penman
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, MA 02139
| | - Monty Krieger
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, MA 02139
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20
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Nieland TJF, Xu S, Penman M, Krieger M. Negatively cooperative binding of high-density lipoprotein to the HDL receptor SR-BI. Biochemistry 2011. [PMID: 21254782 DOI: 10.1021/bi1011657j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Scavenger receptor class B, type I (SR-BI), is a high-density lipoprotein (HDL) receptor, which also binds low-density lipoprotein (LDL), and mediates the cellular selective uptake of cholesteryl esters from lipoproteins. SR-BI also is a coreceptor for hepatitis C virus and a signaling receptor that regulates cell metabolism. Many investigators have reported that lipoproteins bind to SR-BI via a single class of independent (not interacting), high-affinity binding sites (one site model). We have reinvestigated the ligand concentration dependence of (125)I-HDL binding to SR-BI and SR-BI-mediated specific uptake of [(3)H]CE from [(3)H]CE-HDL using an expanded range of ligand concentrations (<1 μg of protein/mL, lower than previously reported). Scatchard and nonlinear least-squares model fitting analyses of the binding and uptake data were both inconsistent with a single class of independent binding sites binding univalent lipoprotein ligands. The data are best fit by models in which SR-BI has either two independent classes of binding sites or one class of sites exhibiting negative cooperativity due to either classic allostery or ensemble effects ("lattice model"). Similar results were observed for LDL. Application of the "infinite dilution" dissociation rate method established that the binding of (125)I-HDL to SR-BI at 4 °C exhibits negative cooperativity. The unexpected complexity of the interactions of lipoproteins with SR-BI should be taken into account when interpreting the results of experiments that explore the mechanism(s) by which SR-BI mediates ligand binding, lipid transport, and cell signaling.
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Affiliation(s)
- Thomas J F Nieland
- Department of Biology, Massachusetts Institute of Technology, Room 68-483, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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21
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Pharmacokinetic, pharmacodynamic, and safety profile of a new cholesteryl ester transfer protein inhibitor in healthy human subjects. Clin Pharmacol Ther 2009; 86:430-7. [PMID: 19587642 DOI: 10.1038/clpt.2009.120] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A new cholesteryl ester (CE) transfer protein (CETP) inhibitor (CP-800,569) was evaluated. Doses of 30-1,800 mg were administered once daily to healthy subjects for 14 days. Serum CP-800,569 levels increased, and CETP activity decreased, in a dose-related manner. Serum levels of high-density lipoprotein (HDL) increased (by a maximum of 156%), and those of low-density lipoprotein (LDL) decreased (by a maximum of 47%). CP-800,569 also had the effect of lowering postprandial triglyceride levels. Trough concentrations of apolipoprotein E (apoE) increased: the maximum increases were 89% for total plasma apoE and 280% for HDL apoE. By contrast, the postprandial increases in total plasma levels of apoE and non HDL apoE were either diminished by CP-800,569 or reversed to decreases. CP-800,569 was very well tolerated, with some nonserious gastrointestinal adverse events seen only with the 1,800-mg dose. No changes in blood pressure (BP) were observed. The possible effects of higher CP-800,569 doses on aldosterone and cortisol levels could not be excluded. The results of this study may be useful in CP-800,569 dose selection.
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22
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Hoekstra M, Ye D, Hildebrand RB, Zhao Y, Lammers B, Stitzinger M, Kuiper J, Van Berkel TJC, Van Eck M. Scavenger receptor class B type I-mediated uptake of serum cholesterol is essential for optimal adrenal glucocorticoid production. J Lipid Res 2009; 50:1039-46. [PMID: 19179307 DOI: 10.1194/jlr.m800410-jlr200] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Impaired scavenger receptor class B type I (SR-BI)-mediated uptake of HDL-cholesterol esters (HDL-CE) induces adrenal insufficiency in mice. Humans contain an alternative route of HDL-CE clearance, namely through the transfer by cholesteryl ester transfer protein (CETP) to apolipoprotein B lipoproteins for subsequent uptake via the LDL receptor. In this study, we determined whether CETP can compensate for loss of adrenal SR-BI. Transgenic expression of human CETP (CETP Tg) in SR-BI knockout (KO) mice increased adrenal HDL-CE clearance from 33-58% of the control value. SR-BI KO/CETP Tg and SR-BI KO mice displayed adrenal hypertrophy due to equally high plasma adrenocorticotropic hormone levels. Adrenal cholesterol levels and plasma corticosterone levels were 38-52% decreased in SR-BI KO mice with and without CETP expression. SR-BI KO/CETP Tg mice also failed to increase their corticosterone level after lipopolysaccharide challenge, leading to an identical >4-fold increased tumor necrosis factor-alpha response compared with controls. These data indicate that uptake of CE via other routes than SR-BI is not sufficient to generate the cholesterol pool needed for optimal adrenal steroidogenesis. In conclusion, we have shown that CETP-mediated transfer of HDL-CE is not able to reverse adrenal insufficiency in SR-BI knockout mice. Thus, SR-BI-mediated uptake of serum cholesterol is essential for optimal adrenal function.
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Affiliation(s)
- Menno Hoekstra
- Division of Biopharmaceutics, Leiden/Amsterdam Center for Drug Research, Gorlaeus Laboratories, 2300RA Leiden, The Netherlands.
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23
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Kopprasch S, Pietzsch J, Ansurudeen I, Graessler J, Krug AW, Ehrhart-Bornstein M, Bornstein SR. Prediabetic and diabetic in vivo modification of circulating low-density lipoprotein attenuates its stimulatory effect on adrenal aldosterone and cortisol secretion. J Endocrinol 2009; 200:45-52. [PMID: 18835979 DOI: 10.1677/joe-08-0293] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Modification of low-density lipoprotein (LDL) and abnormal aldosterone and cortisol metabolism have been implicated in the pathogenesis of type 2 diabetes (DM2) and diabetic vascular disease. Since LDL serves as a major cholesterol source for adrenal steroidogenesis, we investigated whether LDL modification in prediabetic and diabetic subjects influences adrenocortical aldosterone and cortisol release. LDL was isolated from 30 subjects with normal glucose tolerance (NGT-LDL), 30 subjects with impaired glucose tolerance (IGT-LDL), and 26 patients with DM2 (DM2-LDL). Oxidation and glycoxidation characteristics of LDL apolipoprotein B100 of each individual was assessed by gas chromatography-mass spectrometry analysis. Human adrenocortical cells (NCI-H295R) were incubated for 24 h with 100 microg/ml LDL and after removal of supernatants stimulated for a further 24 h with angiotensin II (AngII). In supernatants, aldosterone and cortisol secretion was measured. IGT-LDL and DM2-LDL were substantially more modified than NGT-LDL. Each of the five measured oxidation/glycoxidation markers was significantly positively associated with glycemic control, measured as HbA(1c). LDL from all subjects stimulated both the basal and AngII-induced aldosterone and cortisol release from adrenocortical cells. However, hormone secretion was significantly inversely related to the degree of LDL oxidation/glycoxidation. We conclude that LDL modifications in IGT and DM2 subjects may have significant clinical benefits by counteracting prediabetic and diabetic overactivity of the renin-angiotensin-aldosterone system and enhanced cortisol generation.
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Affiliation(s)
- Steffi Kopprasch
- Department of Internal Medicine 3, Pathological Biochemistry, Carl Gustav Carus Medical School, University of Technology Dresden, Dresden, Germany.
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24
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Bultel S, Helin L, Clavey V, Chinetti-Gbaguidi G, Rigamonti E, Colin M, Fruchart JC, Staels B, Lestavel S. Liver X Receptor Activation Induces the Uptake of Cholesteryl Esters From High Density Lipoproteins in Primary Human Macrophages. Arterioscler Thromb Vasc Biol 2008; 28:2288-95. [DOI: 10.1161/atvbaha.108.175042] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective—
Liver X receptors (LXRs) are oxysterol-activated nuclear receptors regulating reverse cholesterol transport, in part by modulating cholesterol efflux from macrophages to apoAI and HDL via the ABCA1 and ABCG1/ABCG4 pathways. Moreover, LXR activation increases intracellular cholesterol trafficking via the induction of NPC1 and NPC2 expression. However, implication of LXRs in the selective uptake of cholesteryl esters from lipoproteins in human macrophages has never been reported.
Methods and Results—
Our results show that (1) selective CE uptake from HDL
3
is highly efficient in human monocyte-derived macrophages; (2) surprisingly, HDL
3
-CE uptake is strongly increased by LXR activation despite antiatherogenic effects of LXRs; (3) HDL
3
-CE uptake increase is not linked to SR-BI expression modulation but it is dependent of proteoglycan interactions; (4) HDL
3
-CE uptake increase is associated with increased expression and secretion of apoE and LPL, two proteins interacting with proteoglycans; (5) HDL
3
-CE uptake increase depends on the integrity of raft domains and is associated with an increased caveolin-1 expression.
Conclusions—
Our study identifies a new role for LXRs in the control of cholesterol homeostasis in human macrophages. LXR activation results in enhanced dynamic intracellular cholesterol fluxes through an increased CE uptake from HDL and leads to an increased cholesterol availability to efflux to apoAI and HDL.
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Affiliation(s)
- Stephanie Bultel
- From the Institut Pasteur de Lille, Inserm, U545, and Université de Lille 2, Faculté de Pharmacie et de Médecine Lille (S.B., L.H., V.C., G.C.-G., E.R., J.-C.F., B.S., S.L.), France; and Inserm, U837 Centre de Recherche Jean-Pierre Aubert, Université de Lille 2, Faculté de Médecine, Institut de Médecine Prédictive et Recherche Thérapeutique (M.C.), Place de Verdun Lille, France
| | - Lionel Helin
- From the Institut Pasteur de Lille, Inserm, U545, and Université de Lille 2, Faculté de Pharmacie et de Médecine Lille (S.B., L.H., V.C., G.C.-G., E.R., J.-C.F., B.S., S.L.), France; and Inserm, U837 Centre de Recherche Jean-Pierre Aubert, Université de Lille 2, Faculté de Médecine, Institut de Médecine Prédictive et Recherche Thérapeutique (M.C.), Place de Verdun Lille, France
| | - Veronique Clavey
- From the Institut Pasteur de Lille, Inserm, U545, and Université de Lille 2, Faculté de Pharmacie et de Médecine Lille (S.B., L.H., V.C., G.C.-G., E.R., J.-C.F., B.S., S.L.), France; and Inserm, U837 Centre de Recherche Jean-Pierre Aubert, Université de Lille 2, Faculté de Médecine, Institut de Médecine Prédictive et Recherche Thérapeutique (M.C.), Place de Verdun Lille, France
| | - Giulia Chinetti-Gbaguidi
- From the Institut Pasteur de Lille, Inserm, U545, and Université de Lille 2, Faculté de Pharmacie et de Médecine Lille (S.B., L.H., V.C., G.C.-G., E.R., J.-C.F., B.S., S.L.), France; and Inserm, U837 Centre de Recherche Jean-Pierre Aubert, Université de Lille 2, Faculté de Médecine, Institut de Médecine Prédictive et Recherche Thérapeutique (M.C.), Place de Verdun Lille, France
| | - Elena Rigamonti
- From the Institut Pasteur de Lille, Inserm, U545, and Université de Lille 2, Faculté de Pharmacie et de Médecine Lille (S.B., L.H., V.C., G.C.-G., E.R., J.-C.F., B.S., S.L.), France; and Inserm, U837 Centre de Recherche Jean-Pierre Aubert, Université de Lille 2, Faculté de Médecine, Institut de Médecine Prédictive et Recherche Thérapeutique (M.C.), Place de Verdun Lille, France
| | - Morvane Colin
- From the Institut Pasteur de Lille, Inserm, U545, and Université de Lille 2, Faculté de Pharmacie et de Médecine Lille (S.B., L.H., V.C., G.C.-G., E.R., J.-C.F., B.S., S.L.), France; and Inserm, U837 Centre de Recherche Jean-Pierre Aubert, Université de Lille 2, Faculté de Médecine, Institut de Médecine Prédictive et Recherche Thérapeutique (M.C.), Place de Verdun Lille, France
| | - Jean-Charles Fruchart
- From the Institut Pasteur de Lille, Inserm, U545, and Université de Lille 2, Faculté de Pharmacie et de Médecine Lille (S.B., L.H., V.C., G.C.-G., E.R., J.-C.F., B.S., S.L.), France; and Inserm, U837 Centre de Recherche Jean-Pierre Aubert, Université de Lille 2, Faculté de Médecine, Institut de Médecine Prédictive et Recherche Thérapeutique (M.C.), Place de Verdun Lille, France
| | - Bart Staels
- From the Institut Pasteur de Lille, Inserm, U545, and Université de Lille 2, Faculté de Pharmacie et de Médecine Lille (S.B., L.H., V.C., G.C.-G., E.R., J.-C.F., B.S., S.L.), France; and Inserm, U837 Centre de Recherche Jean-Pierre Aubert, Université de Lille 2, Faculté de Médecine, Institut de Médecine Prédictive et Recherche Thérapeutique (M.C.), Place de Verdun Lille, France
| | - Sophie Lestavel
- From the Institut Pasteur de Lille, Inserm, U545, and Université de Lille 2, Faculté de Pharmacie et de Médecine Lille (S.B., L.H., V.C., G.C.-G., E.R., J.-C.F., B.S., S.L.), France; and Inserm, U837 Centre de Recherche Jean-Pierre Aubert, Université de Lille 2, Faculté de Médecine, Institut de Médecine Prédictive et Recherche Thérapeutique (M.C.), Place de Verdun Lille, France
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25
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Depke M, Fusch G, Domanska G, Geffers R, Völker U, Schuett C, Kiank C. Hypermetabolic syndrome as a consequence of repeated psychological stress in mice. Endocrinology 2008; 149:2714-23. [PMID: 18325986 DOI: 10.1210/en.2008-0038] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Stress is a powerful modulator of neuroendocrine, behavioral, and immunological functions. After 4.5-d repeated combined acoustic and restraint stress as a murine model of chronic psychological stress, severe metabolic dysregulations became detectable in female BALB/c mice. Stress-induced alterations of metabolic processes that were found in a hepatic mRNA expression profiling were verified by in vivo analyses. Repeatedly stressed mice developed a hypermetabolic syndrome with the severe loss of lean body mass, hyperglycemia, dyslipidemia, increased amino acid turnover, and acidosis. This was associated with hypercortisolism, hyperleptinemia, insulin resistance, and hypothyroidism. In contrast, after a single acute stress exposure, changes in expression of metabolic genes were much less pronounced and predominantly confined to gluconeogenesis, probably indicating that metabolic disturbances might be initiated already early but will only manifest in repeatedly stressed mice. Thus, in our murine model, repeated stress caused severe metabolic dysregulations, leading to a drastic reduction of the individual's energy reserves. Under such circumstances stress may further reduce the ability to cope with new stressors such as infection or cancer.
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Affiliation(s)
- Maren Depke
- Ernst-Moritz-Arndt-University, Interfaculty Institute of Genetics and Functional Genomics, 17487 Greifswald, Germany
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26
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Botma GJ, Heuveling M, Lamers JMJ, Jansen H, Verhoeven AJM. Cloning, expression, and promoter analysis of hepatic lipase derived from human hyperplastic adrenals. Cell Biochem Biophys 2007; 47:149-58. [PMID: 17406067 DOI: 10.1385/cbb:47:1:149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/11/2022]
Abstract
Human adrenals contain hepatic lipase (HL) activity, which is thought to facilitate the uptake of plasma cholesterol used in steroidogenesis. We show here that full-length HL mRNA is expressed in hyperplastic adrenals of patients with Cushing's disease. In addition, a splice variant that lacks exon-3 was detected in the human adrenals and hepatoma (HepG2) cells, but not in liver. In CAT-reporter assays using human NCI-H295R adrenocortical cells, the HL(-685/+13) promoter region was transcriptionally active, and its activity was enhanced twofold by cAMP. In rat adrenals, the HL gene is exclusively transcribed from an alternative promoter within intron-2, resulting in a variant mRNA that lacks exons 1 and 2. By reverse-transcription PCR, we found no evidence for expression of such a variant mRNA in human adrenals, liver, or HepG2 cells. The presence of both full length mRNA and enzyme activity in human adrenals suggests that part of the HL activity is locally synthesized.
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Affiliation(s)
- Gert-Jan Botma
- Department of Biochemistry, Cardiovascular Research School COEUR, Erasmus MC, Rotterdam, The Netherlands
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27
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Krey T, Moussay E, Thiel HJ, Rümenapf T. Role of the low-density lipoprotein receptor in entry of bovine viral diarrhea virus. J Virol 2006; 80:10862-7. [PMID: 16928760 PMCID: PMC1641791 DOI: 10.1128/jvi.01589-06] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Accepted: 08/15/2006] [Indexed: 12/16/2022] Open
Abstract
Among several proposed cellular receptors for bovine viral diarrhea virus (BVDV), the low-density lipoprotein (LDL) receptor is of special interest because it is also considered a receptor for the related hepatitis C virus. It has been reported that an anti-LDL receptor monoclonal antibody blocked the infection of bovine cells by BVDV and that the resistance of bovine CRIB cells (cells resistant to infection with BVDV) (E. F. Flores and R. O. Donis, Virology 208:565-575, 1995) to BVDV infection was due to a lack of the LDL receptor (V. Agnello et al., Proc. Natl. Acad. Sci. USA 96:12766-12771, 1999). In connection with our studies on BVDV entry, we reevaluated the putative role of the LDL receptor as a cellular receptor for BVDV. It was first clearly demonstrated that neither of two monoclonal antibodies against the LDL receptor inhibited BVDV infection of two bovine cell lines. Furthermore, the LDL receptor was detected on the surface of CRIB cells. The functionality of the LDL receptor on CRIB cells was demonstrated by the internalization of fluorescently labeled LDL. In conclusion, at present no experimental evidence supports an involvement of the LDL receptor in BVDV invasion.
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Affiliation(s)
- Thomas Krey
- Institut für Virologie, Frankfurter Str. 107, D-35392 Giessen, Germany
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28
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Nilsson M, Stulnig TM, Lin CY, Yeo AL, Nowotny P, Liu ET, Steffensen KR. Liver X receptors regulate adrenal steroidogenesis and hypothalamic-pituitary-adrenal feedback. Mol Endocrinol 2006; 21:126-37. [PMID: 16973760 DOI: 10.1210/me.2006-0187] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The nuclear hormone receptors liver X receptor alpha (LXRalpha) (NR1H3) and LXRbeta (NR1H2) are established regulators of cholesterol, lipid, and glucose metabolism and are attractive drug targets for the treatment of diabetes and cardiovascular disease. Adrenal steroid hormones including glucocorticoids and mineralocorticoids are known to interfere with glucose metabolism, insulin signaling, and blood pressure regulation. Here we present genome-wide expression profiles of LXR-responsive genes in both the adrenal and the pituitary gland. LXR activation in cultured adrenal cells inhibited expression of multiple steroidogenic genes and consequently decreased adrenal steroid hormone production. In addition, LXR agonist treatment elevated ACTH mRNA expression and hormone secretion from pituitary cells both in vitro and in vivo. Reduced expression of the glucocortioid-activating enzyme 11beta-hydroxysteroid dehydrogenase 1 in pituitary cells upon LXR activation suggests blunting of the negative feedback of glucocorticoids by LXRs. In conclusion, LXRs independently interfere with the hypothalamic-pituitary-adrenal axis regulation at the level of the pituitary and the adrenal gland.
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Affiliation(s)
- Maria Nilsson
- Department of Biosciences and Nutrition, Karolinska Institutet, S-14157 Huddinge, Sweden
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29
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Murao K, Imachi H, Cao W, Yu X, Li J, Yoshida K, Ahmed RAM, Matsumoto K, Nishiuchi T, Wong NCW, Ishida T. High-density lipoprotein is a potential growth factor for adrenocortical cells. Biochem Biophys Res Commun 2006; 344:226-32. [PMID: 16600185 DOI: 10.1016/j.bbrc.2006.03.131] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Accepted: 03/20/2006] [Indexed: 01/02/2023]
Abstract
The entry of cholesterol contained within high-density lipoprotein (HDL) into adrenocortical cells is mediated by a human homologue of SR-BI, CD36, and LIMPII Analogous-1 (CLA-1) and thus augmenting their growth. To address the role of CLA-1, we created a mutant mCLA that lacked the C-terminal tail. HDL CE selective uptake by cells carrying the mCLA-1 receptor was fully active and equivalent to those transfected with full-length CLA-1 (fCLA-1). Expression of mCLA inhibited the proliferation of an adrenocortical cell line and the incorporation of [(3)H]thymidine into the cells. This effect was sensitive to wortmannin, an inhibitor of phosphoinositide 3-kinase (PI3K). Our transcriptional studies revealed that the inhibitory action of mCLA required the transcriptional factor AP-1 and the effect of HDL on AP-1 activation was also abrogated by wortmannin. These findings raise the possibility that the inhibitors of the effects of HDL may be of therapeutic value for adrenocortical tumor.
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Affiliation(s)
- Koji Murao
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe Miki-cho, Kita-gun, Kagawa, Japan.
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30
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Lopez D, McLean MP. Estrogen regulation of the scavenger receptor class B gene: Anti-atherogenic or steroidogenic, is there a priority? Mol Cell Endocrinol 2006; 247:22-33. [PMID: 16297529 DOI: 10.1016/j.mce.2005.10.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Revised: 10/13/2005] [Accepted: 10/13/2005] [Indexed: 02/06/2023]
Abstract
High density lipoprotein (HDL) participates in reverse cholesterol transport and in the delivery of cholesterol to the liver and steroidogenic tissues by a mechanism called "selective lipid uptake" which is mediated by the HDL receptor, scavenger receptor B type I (SR-BI). Overexpression of SR-BI suppresses atherosclerosis by increasing reverse cholesterol transport. In contrast, genetic ablation of SR-BI has a negative effect on cardiovascular physiology in both males and females and a gender specific negative impact on female fertility. Cholesterol is essential for mammalian embryonic development as a necessary component of cell membranes and as a substrate for steroidogenesis. The SR-BI receptor is highly expressed in the human placenta allowing the growing fetus to obtain a considerable portion of cholesterol from maternal lipoproteins. Estrogen, which plays an important role in maintaining pregnancy, has been shown to enhance plasma HDL levels and promote reverse cholesterol transport. Since SR-BI is the major determinant of serum HDL levels, direct regulation of the SR-BI gene by estrogen is theorized. The objective of this manuscript is to summarize the current information related to estrogen regulation of the gene that codes for the SR-BI receptor.
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Affiliation(s)
- Dayami Lopez
- Department of Obstetrics & Gynecology, University of South Florida, College of Medicine, 12901 Bruce B Downs Boulevard, MDC 37, Tampa, FL 33612, USA
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31
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Tosi MR, Tugnoli V. Cholesteryl esters in malignancy. Clin Chim Acta 2005; 359:27-45. [PMID: 15939411 DOI: 10.1016/j.cccn.2005.04.003] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Revised: 03/31/2005] [Accepted: 04/04/2005] [Indexed: 01/23/2023]
Abstract
Cholesteryl esters, formed by the esterification of cholesterol with long-chain fatty acids, on one hand, are the means by which cholesterol is transported through the blood by lipoproteins, on the other, the way cholesterol itself can be accumulated in the cells. Therefore, these important molecules play an active part in metabolic pathways that form the basis of cholesterol trafficking and homeostasis. The role of different regulatory mechanisms in cholesterol homeostasis in physiologic and neoplastic conditions with emphasis on intracellular content of cholesteryl esters is here reviewed. Numerous studies carried out on tumor cell lines, experimental tumors, and human tumors have shown an abnormal cholesterol metabolism that is reflected by an increase in intracellular cholesteryl esters due to an alteration in all the mechanisms that form the basis of regulation, in particular: cholesterol de novo biosynthesis; uptake of exogenous cholesterol LDL receptor mediated; cholesterol esterification mediated by the ACAT activity; cholesterol efflux HDL receptor mediated. The most recent analytic-spectroscopic applications that permit cholesteryl ester determination on tumor lipidic extracts and directly in vivo are also reported. This review gives an overview of cholesterol homeostasis in physiological and pathological conditions where cholesteryl esters are over-expressed.
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Affiliation(s)
- Maria R Tosi
- ITOI-CNR, presso IOR, via di Barbiano 1/10, 40136, Bologna, Italy.
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32
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Gonçalves RP, Rodrigues DG, Maranhão RC. Uptake of high density lipoprotein (HDL) cholesteryl esters by human acute leukemia cells. Leuk Res 2005; 29:955-9. [PMID: 15978947 DOI: 10.1016/j.leukres.2005.01.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2004] [Revised: 01/27/2005] [Accepted: 01/31/2005] [Indexed: 10/25/2022]
Abstract
Hypocholesterolemia is a common finding in patients with acute leukemia (AL). The aim of this study is to investigate if blast myeloid and lynfoid cells take up more high density lipoprotein (HDL) cholesteryl esters than normal cells of the same origin. The HDL-cholesteryl ester uptake followed a kinetic saturation process. Higher maximal velocity rates were found in lymphoblasts and myeloblasts compared to normal cells (Vmax=3.51+/-0.30/3.61+/-0.16 and 2.54+/-0.12/2.28+/-0.12 microg/mg, respectively). High density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and total cholesterol were significantly lower in AL patients (p<0.05); no differences were observed in triglyceride or VLDL-C levels. In conclusion, low HDL-C levels observed in AL may be related to an overexpression of a selective HDL-cholesteryl ester putative site.
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Affiliation(s)
- Romelia Pinheiro Gonçalves
- The Heart Institute (InCor) of the São Paulo University Medical School Hospital, Laboratório de Metabolismo de Lípides. Av. Dr. Enéas de Carvalho Aguiar, 44, 1 ss, São Paulo 05403-000, Brazil
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33
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Rhainds D, Brissette L. The role of scavenger receptor class B type I (SR-BI) in lipid trafficking. defining the rules for lipid traders. Int J Biochem Cell Biol 2004; 36:39-77. [PMID: 14592533 DOI: 10.1016/s1357-2725(03)00173-0] [Citation(s) in RCA: 158] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The scavenger receptor class B type I (SR-BI) is a 509-amino acid, 82 kDa glycoprotein, with two cytoplasmic C- and N-terminal domains separated by a large extracellular domain. The aim of this review is to define the role of SR-BI as a lipoprotein receptor responsible for selective uptake of cholesteryl esters (CE) from high density lipoprotein (HDL) and low density lipoprotein (LDL) and free cholesterol (FC) efflux to lipoprotein acceptors. These activities depend on lipoprotein binding to its extracellular domain and subsequent lipid exchange at the plasma membrane. CE selective uptake supplies cholesterol to liver and steroidogenic tissues, for biliary cholesterol secretion and steroid hormone synthesis. Genetically modified mice have confirmed SR-BI's major role in tissue cholesterol uptake and in reverse cholesterol transport, i.e. cholesterol turnover. Accordingly, cellular cholesterol level, estrogens and trophic hormones regulate SR-BI expression by both transcriptional and post-transcriptional mechanisms. Importantly, mouse SR-BI overexpression has both corrective and preventive effects on atherosclerosis. Human SR-BI has very similar tissue distribution, binding properties and lipid transfer activities compared to rodent SR-BI. However, human plasma has most of its cholesterol in LDL. Thus, there is considerable interest to develop anti-atherogenic strategies involving human SR-BI-mediated increases in reverse cholesterol transport through HDL and/or LDL.
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MESH Headings
- Amino Acid Sequence
- Animals
- Biological Transport, Active
- CD36 Antigens
- Cell Membrane/chemistry
- Cell Membrane/genetics
- Cell Membrane/metabolism
- Cell Membrane/physiology
- Humans
- Lipid Metabolism
- Lipoproteins/metabolism
- Models, Biological
- Promoter Regions, Genetic
- Protein Structure, Tertiary
- Receptors, Immunologic/chemistry
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Receptors, Immunologic/physiology
- Receptors, Scavenger
- Scavenger Receptors, Class B
- Tissue Distribution
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Affiliation(s)
- David Rhainds
- Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succ. Centre-Ville, Montreal, Que., Canada H3C 3P8.
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34
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Abstract
In the adrenal glomerulosa cell, aldosterone is synthesized from cholesterol, which is supplied to the cell and stored under the form of cholesterol esters, then hydrolyzed to be transferred to the mitochondrial outer membrane and finally transported to the inner membrane where the P450 side-chain cleavage enzyme will convert it to pregnenolone. Angiotensin II (AngII), one of the major physiological regulators of mineralocorticoid synthesis, appears to affect most of the steps along this cascade and thus to exert a powerful control over the use of cholesterol for aldosterone production.
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Affiliation(s)
- Alessandro M Capponi
- Division of Endocrinology, Diabetology and Nutrition, Faculty of Medicine, University Hospital, 24 rue Micheli-du-Crest, CH-1211 Geneva 14, Switzerland.
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35
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Rigotti A, Miettinen HE, Krieger M. The role of the high-density lipoprotein receptor SR-BI in the lipid metabolism of endocrine and other tissues. Endocr Rev 2003; 24:357-87. [PMID: 12788804 DOI: 10.1210/er.2001-0037] [Citation(s) in RCA: 312] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Because cholesterol is a precursor for the synthesis of steroid hormones, steroidogenic tissues have evolved multiple pathways to ensure adequate supplies of cholesterol. These include synthesis, storage as cholesteryl esters, and import from lipoproteins. In addition to endocytosis via members of the low-density lipoprotein receptor superfamily, steroidogenic cells acquire cholesterol from lipoproteins by selective lipid uptake. This pathway, which does not involve lysosomal degradation of the lipoprotein, is mediated by the scavenger receptor class B type I (SR-BI). SR-BI is highly expressed in steroidogenic cells, where its expression is regulated by various trophic hormones, as well as in the liver. Studies of genetically manipulated strains of mice have established that SR-BI plays a key role in regulating lipoprotein metabolism and cholesterol transport to steroidogenic tissues and to the liver for biliary secretion. In addition, analysis of SR-BI-deficient mice has shown that SR-BI expression is important for alpha-tocopherol and nitric oxide metabolism, as well as normal red blood cell maturation and female fertility. These mouse models have also revealed that SR-BI can protect against atherosclerosis. If SR-BI plays similar physiological and pathophysiological roles in humans, it may be an attractive target for therapeutic intervention in cardiovascular and reproductive diseases.
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Affiliation(s)
- Attilio Rigotti
- Departamento de Gastroenterología, Facultad de Medicina, Pontificia Universidad Católica, Santiago, Chile
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36
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Pilon A, Martin G, Bultel-Brienne S, Junquero D, Delhon A, Fruchart JC, Staels B, Clavey V. Regulation of the scavenger receptor BI and the LDL receptor by activators of aldosterone production, angiotensin II and PMA, in the human NCI-H295R adrenocortical cell line. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1631:218-28. [PMID: 12668173 DOI: 10.1016/s1388-1981(03)00020-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In human adrenal cells, cholesterol for steroidogenesis is derived from both high-density lipoproteins (HDL) via the Scavenger Receptor Class B Type I (SR-BI) and low-density lipoproteins (LDL) via the LDL receptor pathway. We have previously shown that, in the human adrenocortical carcinoma cell line, NCI-H295R, SR-BI and LDL receptor expression and steroidogenesis are coordinately regulated by activators of protein kinase A (PKA) leading to glucocorticoid synthesis. In the present study, we studied whether SR-BI and LDL receptor expression are regulated by activators of the protein kinase C (PKC) signaling pathway, such as angiotensin II, which stimulate mineralocorticoid synthesis. First, it is shown that, in NCI-H295R cells, aldosterone synthesis is stimulated by a phorbol ester (phorbol-12-myristate-13 acetate, PMA), a potent PKC activator. Northern blot analysis indicated that both angiotensin II and PMA stimulated SR-BI expression in a time-dependent manner. LDL receptor expression is slightly stimulated by PMA. The induction of SR-BI gene expression occurs at the transcriptional level, via an activation of the human SR-BI promoter, as shown by transient transfection experiments. Finally, SR-BI protein level was increased in angiotensin II- and PMA-stimulated cells, resulting in higher lipoprotein binding and specific cholesteryl ester (CE) uptake from HDL, as well from LDL after angiotensin II and PMA stimulation.
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MESH Headings
- Adrenal Cortex/drug effects
- Adrenal Cortex/metabolism
- Aldosterone/biosynthesis
- Aldosterone/metabolism
- Angiotensin II/pharmacology
- CD36 Antigens
- Cholesterol Esters/metabolism
- Cholesterol, HDL/metabolism
- Cholesterol, LDL/metabolism
- Gene Expression Regulation/drug effects
- Humans
- Membrane Proteins
- RNA, Messenger/biosynthesis
- Receptors, Immunologic/biosynthesis
- Receptors, Immunologic/metabolism
- Receptors, LDL/biosynthesis
- Receptors, LDL/metabolism
- Receptors, Lipoprotein
- Receptors, Scavenger
- Scavenger Receptors, Class B
- Tetradecanoylphorbol Acetate/pharmacology
- Tumor Cells, Cultured
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Affiliation(s)
- Antoine Pilon
- INSERM U545, Institut Pasteur de Lille and Faculté de Pharmacie, Université de Lille 2, 59019, Lille, France
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37
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Wadsack C, Hirschmugl B, Hammer A, Levak-Frank S, Kozarsky KF, Sattler W, Malle E. Scavenger receptor class B, type I on non-malignant and malignant human epithelial cells mediates cholesteryl ester-uptake from high density lipoproteins. Int J Biochem Cell Biol 2003; 35:441-54. [PMID: 12565706 DOI: 10.1016/s1357-2725(02)00272-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Hepatoma cell lines serve as a suitable model to study hepatic clearance of lipoprotein-associated cholesteryl esters (CEs). The present study aimed at investigating holoparticle-association of and selective CE-uptake from human high density lipoprotein subclass 3 (HDL3) by non-malignant adult (Chang-liver) and non-malignant fetal (WRL-68) epithelial cell lines as well as a hepatocellular carcinoma (HUH-7) cell line. Binding properties of 125I-HDL3 at 4 and 37 degrees C were similar for all three cell lines while degradation rates were highest for Chang-liver cells. Calculating the selective uptake of HDL3-associated CEs as the difference between [3H]CE- and 125I-HDL3 cell-association revealed that the selective lipid uptake and holoparticle-association was similar in Chang-liver while in WRL-68 and HUH-7 cells pronounced capacity for lipid tracer uptake in excess of holoparticle uptake was measured. Using RT-PCR, Northern and Western blot analysis, as well as immunocytochemical technique pronounced expression of scavenger receptor class B, type I (SR-BI) but not SR-BII (a splice variant of SR-BI less efficient for selective CE-uptake than SR-BI) could be identified in HUH-7 and WRL-68 cells. A polyclonal antiserum raised against SR-BI significantly decreased cell-association of [3H]CE-HDL3 in HUH-7 and WRL-68. The present findings suggest that the capacity for selective cholesteryl ester-uptake from high density lipoprotein by malignant and normal epithelial cells from the liver depends on expression of the scavenger receptor class B, type I.
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Affiliation(s)
- Christian Wadsack
- Institute of Medical Biochemistry and Molecular Biology, Karl-Franzens University Graz, Harrachgasse 21, A-8010, Graz, Austria
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38
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Briand O, Lestavel S, Pilon A, Torpier G, Fruchart JC, Clavey V. SR-BI does not require raft/caveola localisation for cholesteryl ester selective uptake in the human adrenal cell line NCI-H295R. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1631:42-50. [PMID: 12573448 DOI: 10.1016/s1388-1981(02)00354-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Class B type I scavenger receptor (SR-BI) mediates the selective uptake of high-density lipoprotein (HDL)-derived cholesteryl esters (HDL-CE) in steroidogenic cells and hepatocytes. SR-BI is enriched in the caveolae of some cell types, genetically modified or not, and these domains have already been shown to constitute primary acceptors for HDL-CE. Nevertheless, the fate of caveola-free cell types has not yet been discussed.NCI-H295R, a human adrenal cell line, highly active in HDL-CE uptake via SR-BI, does not display any morphologically defined caveolae and expresses caveolin at a very low level. Using two different fractionation protocols, we have shown, in this cell type, that SR-BI is homogeneously distributed along the plasma membrane and consists principally of a non-raft membrane-associated pool. Raft destabilisation and caveolin-1 displacement from plasma membrane did not modify the SR-BI-mediated HDL-CE selective uptake. Moreover, the induction of SR-BI expression that is associated with increased CE selective uptake was not associated with any modification in caveolin-1 expression or any raft-targeting mechanism of SR-BI in NCI-H295R. In conclusion, we provide evidence that SR-BI does not require raft/caveola localisation to be implicated in CE selective uptake either in basal or in induced conditions.
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Affiliation(s)
- Olivier Briand
- Inserm UR545, Institut Pasteur de Lille and Faculté des Sciences Pharmaceutiques et Biologiques, Université de Lille 2, 1 rue du Professeur Calmette BP245, 59019, Lille, France
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39
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Santini SA, Carrozza C, Lulli P, Zuppi C, CarloTonolo G, Musumeci S. Atorvastatin Treatment Does Not Affect Gonadal and Adrenal Hormones in Type 2 Diabetes Patients with Mild to Moderate Hypercholesterolemia. J Atheroscler Thromb 2003; 10:160-4. [PMID: 14564085 DOI: 10.5551/jat.10.160] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Atorvastatin, a second generation synthetic 3-hydroxy 3-methylglutaryl-coenzyme-A (HMG-CoA) reductase inhibitor used in the treatment of hypercholesterolemia, reduces both intracellular cholesterol synthesis and serum cholesterol levels, and this could have a potential negative impact on gonadal and adrenal steroidogenesis. Hypercholesterolemia in type 2 diabetes, even when mild, must be treated in an aggressive way, due to the more strict therapeutic goals than in the non diabetic population. Since the wide use of 3-hydroxy 3-methylglutaryl-coenzyme-A (HMG-CoA) reductase inhibitor (statins) in type 2 diabetes, the main aim of our study was to evaluate the effects of "therapeutic" doses of atorvastatin on gonadal and adrenal hormones in 24 type 2 diabetic patients (16 males and 8 postmenopausal females), with mild to moderate hypercholesterolemia (LDL-cholesterol = 150.1 +/- 32.0 and 189.9 +/- 32.9 mg/dl, respectively) studied before and after a 3 months treatment with atorvastatin (20 mg/day). In all patients, lipids and serum cortisol, dehydroepiandrosterone sulphate (DHEA-S), androstendione and sex hormone binding globulin (SHBG) were measured, with the addition, only in males, of testosterone and free testosterone index. After atorvastatin treatment a significant decrease in total and LDL cholesterol was observed (p < 0.05), while HDL-cholesterol did not significantly change ( p = N.S.), as no significant difference was found between steroid hormones measured before and after atorvastatin either in male and females. In conclusion, our data suggest that, in type 2 diabetic patients, the use of atorvastatin has no clinically important effects on either gonadal or adrenal steroid hormones.
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Affiliation(s)
- Stefano A Santini
- Institute of Biochemistry and Clinical Biochemistry, Catholic University School of Medicine, Rome, Italy
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40
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Azhar S, Reaven E. Scavenger receptor class BI and selective cholesteryl ester uptake: partners in the regulation of steroidogenesis. Mol Cell Endocrinol 2002; 195:1-26. [PMID: 12354669 DOI: 10.1016/s0303-7207(02)00222-8] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The steroidogenic tissues have a special requirement for cholesterol, which is used as a substrate for steroid hormone biosynthesis. In many species this cholesterol is obtained from plasma lipoproteins by a unique pathway in which circulating lipoproteins bind to the surface of the steroidogenic cells and contribute their cholesteryl esters to the cells by a 'selective' process in which the whole lipoprotein particle does not enter the cell. This review describes the lipoprotein selective cholesteryl ester uptake process and its specific partnership with the HDL receptor, scavenger receptor class BI (SR-BI). It describes the characteristics of the selective pathway, and the molecular properties, localization, regulation, anchoring sites and potential mechanisms of action of SR-BI in facilitating cholesteryl ester uptake by steroidogenic cells.
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Affiliation(s)
- Salman Azhar
- Geriatric Research, Education and Clinical Center, GRECC-182B, VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, CA 94304, USA.
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41
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Abstract
In addition to intracellular cholesterol synthesis, plasma low- and high-density lipoproteins (LDL and HDL, respectively) are the major potential sources of a cholesterol precursor for steroid synthesis in all steroidogenic tissues. LDL- and HDL-cholesterol are taken up by cells through entirely distinct mechanisms. In the case of aldosterone production in the zona glomerulosa of the adrenal cortex, it has been assumed in the past that LDL is the major supplier of cholesterol. However, recent developments, in particular the discovery of the scavenger receptor class B type I for HDL and the characterization of its properties, have questioned this view. In fact, the nature of the challenging factor (angiotensin II or adrenocorticotropic hormone) appears to determine which pool of cholesterol is preferentially mobilized and which pathway (LDL receptor endocytosis or selective uptake through the HDL receptor) is regulated.
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Affiliation(s)
- Alessandro M Capponi
- Division of Endocrinology and Diabetology, University Hospital, 24, rue Micheli-du-Crest, CH-1211 Geneva 14, Switzerland.
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42
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Cherradi N, Bideau M, Arnaudeau S, Demaurex N, James RW, Azhar S, Capponi AM. Angiotensin II promotes selective uptake of high density lipoprotein cholesterol esters in bovine adrenal glomerulosa and human adrenocortical carcinoma cells through induction of scavenger receptor class B type I. Endocrinology 2001; 142:4540-9. [PMID: 11564720 DOI: 10.1210/endo.142.10.8412] [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] [Indexed: 11/19/2022]
Abstract
Angiotensin II is one of the main physiological regulators of aldosterone biosynthesis in the zona glomerulosa of the adrenal cortex. The hormone stimulates intracellular cholesterol mobilization to the mitochondrion for steroid biosynthesis. Here we have examined whether angiotensin II also modulates exogenous lipoprotein cholesterol ester supply to the steroidogenic machinery and whether this control is exerted on the selective transport of high density lipoprotein-derived cholesterol ester to intracellular lipid droplets through the scavenger receptor class B type I. In bovine adrenal glomerulosa and human NCI H295R adrenocortical carcinoma cells, high density lipoprotein stimulated steroid production. Angiotensin II pretreatment for 24 h potentiated this response. Fluorescence microscopy of cellular uptake of reconstituted high density lipoprotein containing a fluorescent cholesterol ester revealed an initial, time-dependent narrow labeling of the cell membrane followed by an intense accumulation of the fluorescent cholesterol ester within lipid droplets. At all time points, labeling was more pronounced in cells that had been treated for 24 h with angiotensin II. Fluorescence incorporation into cells was prevented by a monoclonal antibody directed against apolipoprotein A-I. Upon quantitative fluorometric determination, cholesterol ester uptake in angiotensin II-treated bovine cells was increased to 175 +/- 15% of controls after 2 h and to 260 +/- 10% after 4 h of exposure to fluorescent high density lipoprotein. The amount of scavenger receptor class B type I protein detected in cells treated with angiotensin II for 24 h reached 203 +/- 12% of that measured in control cells (n = 3, P < 0.01). In contrast, low density lipoprotein receptors were only minimally affected by angiotensin II treatment. This increase in scavenger receptor class B type I protein was associated with a 3-fold induction of scavenger receptor class B type I mRNA, which could be prevented by actinomycin D but not by cycloheximide. Similar results were obtained in the human adenocarcinoma cell line H295R. These observations show that angiotensin II regulates the scavenger receptor class B type I-mediated selective transport of lipoprotein cholesterol ester across the cell membrane as a major source of precursor for mineralocorticoid biosynthesis in both human and bovine adrenal cells.
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Affiliation(s)
- N Cherradi
- Division of Endocrinology and Diabetology, Faculty of Medicine, University Hospital, CH-1211 Geneva, Switzerland
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43
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Junquero D, Pilon A, Carilla-Durand E, Patoiseau JF, Tarayre JP, Torpier G, Staels B, Fruchart JC, Colpaert FC, Clavey V, Delhon A. Lack of toxic effects of F 12511, a novel potent inhibitor of acyl-coenzyme A: cholesterol O-acyltransferase, on human adrenocortical cells in culture. Biochem Pharmacol 2001; 61:387-98. [PMID: 11226372 DOI: 10.1016/s0006-2952(00)00555-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Inhibition of acyl-coenzyme A: cholesterol O-acyltransferase (EC 2.3.1.26; ACAT) reduces intracellular cholesteryl esters that are substrates for steroidogenesis in adrenal cells. The adrenal side effects of ACAT inhibitors remain a key point for their development as antiatherosclerotic agents. The aim of this study was to characterize the effects of a novel and powerful ACAT inhibitor, F 12511 (S)-2',3',5'-trimethyl-4'-hydroxy-alpha-dodecylthio-phenylacetanilide, on the NCI-H295R cell line, which has functional properties comparable to those of normal human adrenal cells. F 12511 incubated with cultured cells for 4-72 hr strongly inhibited cholesteryl oleate formation. The concentrations required to produce 50% inhibition (IC50) values) ranged from 20 to 50 nM; in the presence of low-density lipoproteins (LDL), this effect was paralleled by a decrease in cholesteryl ester mass and an increase in intracellular free cholesterol. At concentrations 100-fold larger than the IC(50) value for up to 48 hr, F 12511 reduced neither the basal release of cortisol and aldosterone nor the production of cortisol stimulated by forskolin. F 12511 did not modify the mRNA levels of the steroidogenic enzyme genes cytochrome P450 cholesterol side-chain cleavage (P450scc), cytochrome P450 17alpha-hydroxylase (P450c17), or cytochrome P450 21-hydroxylase (P450c21) or those of the LDL receptor and high-density lipoprotein scavenger receptor class B, type I (SR-BI) genes, either in the presence or absence of adenosine 3',5'-cyclic monophosphate stimulation for 24 hr. Exposure to F 12511 at up to 3 microM for 24 or 48 hr did not result in significant change in morphological and ultrastructural characteristics; the cytoplasm contained large numbers of mitochondria with intact crystae, and the same typical features of secretory activity were observed in NCI-H295R control cells. Exposure to 3 microM of F 12511 for 96 hr also did not affect cell viability. These data demonstrate that reduction of the substrate for steroidogenesis by the ACAT inhibitor F 12511 impairs neither steroid production nor transcription of genes involved in steroidogenesis and lipoprotein uptake in the pluripotent human adrenal cell line NCI-H295R.
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Affiliation(s)
- D Junquero
- Centre de Recherche Pierre Fabre, 17 Avenue Jean Moulin, F-81106 Castres Cédex, France.
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44
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Williams DL, Temel RE, Connelly MA. Roles of scavenger receptor BI and APO A-I in selective uptake of HDL cholesterol by adrenal cells. Endocr Res 2000; 26:639-51. [PMID: 11196441 DOI: 10.3109/07435800009048584] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Adrenal cells obtain cholesterol for steroid production via the selective uptake of cholesteryl ester (CE) from HDL particles, a process in which CE is transferred to the plasma membrane without degradation of the HDL particle. Although this process has been studied for two decades, only recently have the receptor and the HDL ligand been identified. Scavenger class B, type I, (SR-BI) is regulated by ACTH in adrenocortical cells in parallel with steroid production. Antibody to SR-BI blocks the uptake and utilization of HDL CE for steroid production in Y1-BS1 adrenal cells. The adrenal glands of SR-BI knockout mice are depleted in cholesterol providing complementary evidence that SR-BI is responsible for HDL CE accumulation in adrenal cells. SR-BI-mediated HDL CE selective uptake is a two-step process in which SR-BI first interacts with multiple sites in apoA-I with the amphipathic inverted alpha-helical repeat units of apoA-I serving as recognition motifs. This is followed by efficient CE transfer down its concentration gradient to the plasma membrane, a process requiring the extracellular domain of SR-BI. Other scavenger receptors bind HDL but do not afford the CE transfer step. Adrenal glands from apoA-I knockout mice lack CE stores, indicating that apoAI is essential for HDL selective uptake in vivo. ApoA-I knockout HDL particles bind normally to SR-BI but do not permit efficient CE transfer to the cell. These findings suggest that apoA-I has an important role in the transfer of HDL CE that goes beyond its function as a ligand for interaction with SR-BI.
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Affiliation(s)
- D L Williams
- Department of Pharmacological Sciences, University Medical Center, State University of New York at Stony Brook, 11794, USA
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Chinetti G, Gbaguidi FG, Griglio S, Mallat Z, Antonucci M, Poulain P, Chapman J, Fruchart JC, Tedgui A, Najib-Fruchart J, Staels B. CLA-1/SR-BI is expressed in atherosclerotic lesion macrophages and regulated by activators of peroxisome proliferator-activated receptors. Circulation 2000; 101:2411-7. [PMID: 10821819 DOI: 10.1161/01.cir.101.20.2411] [Citation(s) in RCA: 319] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The scavenger receptors are cell-surface receptors for native and modified lipoproteins that play a critical role in the accumulation of lipids by macrophages. CLA-1/SR-BI binds HDL with high affinity and is involved in the cholesterol reverse-transport pathway. Peroxisome proliferator-activated receptors (PPARs) are transcription factors regulating the expression of genes implicated in lipid metabolism, cellular differentiation, and inflammation. Here, we investigated the expression of CLA-1/SR-BI in macrophages and its regulation by PPARs. METHODS AND RESULTS CLA-1 is undetectable in human monocytes and is induced upon differentiation into macrophages. Immunohistological analysis on human atherosclerotic lesions showed high expression of CLA-1 in macrophages of the lipid core colocalizing with PPARalpha and PPARgamma staining. Activation of PPARalpha and PPARgamma resulted in the induction of CLA-1 protein expression in monocytes and in differentiated macrophages. Finally, SR-BI expression is increased in atherosclerotic lesions of apoE-null mice treated with either PPARgamma or PPARalpha ligands. CONCLUSIONS Our data demonstrate that CLA-1/SR-BI is expressed in atherosclerotic lesion macrophages and induced by PPAR activation, identifying a potential role for PPARs in cholesterol homeostasis in atherosclerotic lesion macrophages.
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Affiliation(s)
- G Chinetti
- U.325 INSERM, Département d'Athérosclerose, Institut Pasteur de Lille, France
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46
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Abstract
The HDL receptor scavenger receptor class B type I (SR-BI), which mediates selective HDL cholesterol uptake, plays a role in murine HDL metabolism, reverse cholesterol transport and whole-body cholesterol homeostasis. SR-BI is found in the liver, where its expression is regulated by estrogen, dietary cholesterol and fat, and controls murine plasma HDL cholesterol levels and bile cholesterol secretion. SR-BI is also highly expressed in rodent steroidogenic cells, where it facilitates cholesterol uptake for storage or steroid hormone synthesis and where its expression is regulated by trophic hormones. The detailed mechanism(s) underlying SR-BI-mediated selective cholesterol uptake have not yet been elucidated. Further analysis of the molecular and cellular bases of SR-BI regulation and function should provide new insights into the physiology and pathophysiology of cholesterol metabolism.
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Affiliation(s)
- B Trigatti
- Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA
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Resink TJ, Kuzmenko YS, Kern F, Stambolsky D, Bochkov VN, Tkachuk VA, Erne P, Niermann T. LDL binds to surface-expressed human T-cadherin in transfected HEK293 cells and influences homophilic adhesive interactions. FEBS Lett 1999; 463:29-34. [PMID: 10601632 DOI: 10.1016/s0014-5793(99)01594-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
T-cadherin (T-cad) is an unusual glycosylphosphatidylinositol-anchored member of the cadherin family of cell adhesion molecules. Binding of low density lipoproteins (LDLs) to T-cad can be demonstrated on Western blots of smooth muscle cell lysates, membranes and purified proteins. Using HEK293 cells transfected with human T-cad cDNA (T-cad+), we have investigated the adhesion properties of expressed mature and precursor proteins and examined the postulate that LDL represents a physiologically relevant ligand for T-cad. T-cad+ exhibits an increased Ca(2+)-dependent aggregation (vs. control) that was reduced by selective proteolytic cleavage of precursor T-cad and abolished after either proteolytic or phosphatidylinositol-specific phospholipase C (PI-PLC) cleavage of both mature and precursor proteins, indicating that both proteins function in intercellular adhesion. T-cad+ exhibited a significantly increased specific cell surface-binding of [(125)I]-LDL that was sensitive to PI-PLC pre-treatment of cells. Ca(2+)-dependent intercellular adhesion of T-cad+ was significantly inhibited by LDL. Our results support the suggestion that LDL is a physiologically relevant ligand for T-cad.
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Affiliation(s)
- T J Resink
- Laboratory for Cardiovascular Research, Department of Research, Basel University Hospital, CH 4031, Basel, Switzerland.
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48
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Abstract
The scavenger receptor class B, type I (SR-BI) is an HDL receptor that mediates selective cholesterol uptake from HDL to cells. In rodents, SR-BI has a critical influence on plasma HDL-cholesterol concentration and structure, the delivery of cholesterol to steroidogenic tissues, female fertility, and biliary cholesterol concentration. SR-BI can also serve as a receptor for non-HDL lipoproteins and appears to play an important role in reverse cholesterol transport. Recent studies involving the manipulation of SR-BI expression in mice, either using adenovirus-mediated or transgenic hepatic overexpression or using homologous recombination for complete functional ablation, indicate that the expression of SR-BI protects against atherosclerosis. If SR-BI has a similar activity in humans, it may become an attractive target for therapeutic intervention.
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Affiliation(s)
- M Krieger
- Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA.
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49
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Sun Y, Wang N, Tall AR. Regulation of adrenal scavenger receptor-BI expression by ACTH and cellular cholesterol pools. J Lipid Res 1999. [DOI: 10.1016/s0022-2275(20)34896-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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