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Papadopoulos V, Aghazadeh Y, Fan J, Campioli E, Zirkin B, Midzak A. Translocator protein-mediated pharmacology of cholesterol transport and steroidogenesis. Mol Cell Endocrinol 2015; 408:90-8. [PMID: 25818881 PMCID: PMC4417383 DOI: 10.1016/j.mce.2015.03.014] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 03/16/2015] [Accepted: 03/17/2015] [Indexed: 12/17/2022]
Abstract
Steroidogenesis begins with cholesterol transfer into mitochondria through the transduceosome, a complex composed of cytosolic proteins that include steroidogenesis acute regulatory protein (STAR), 14-3-3 adaptor proteins, and the outer mitochondrial membrane proteins Translocator Protein (TSPO) and Voltage-Dependent Anion Channel (VDAC). TSPO is a drug- and cholesterol-binding protein found at particularly high levels in steroid synthesizing cells. Its aberrant expression has been linked to cancer, neurodegeneration, neuropsychiatric disorders and primary hypogonadism. Brain steroids serve as local regulators of neural development and excitability. Reduced levels of these steroids have been linked to depression, anxiety and neurodegeneration. Reduced serum testosterone is common among subfertile young men and aging men, and is associated with depression, metabolic syndrome and reduced sexual function. Although testosterone-replacement therapy is available, there are undesired side-effects. TSPO drug ligands have been proposed as therapeutic agents to regulate steroid levels in the brain and testis.
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Affiliation(s)
- Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada; Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada; Departments of Biochemistry, McGill University, Montreal, Quebec, Canada.
| | - Yasaman Aghazadeh
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Jinjiang Fan
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Enrico Campioli
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Barry Zirkin
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Andrew Midzak
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Departments of Biochemistry, McGill University, Montreal, Quebec, Canada
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Chung JY, Chen H, Midzak A, Burnett AL, Papadopoulos V, Zirkin BR. Drug ligand-induced activation of translocator protein (TSPO) stimulates steroid production by aged brown Norway rat Leydig cells. Endocrinology 2013; 154:2156-65. [PMID: 23525219 PMCID: PMC3740486 DOI: 10.1210/en.2012-2226] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Translocator protein (TSPO; 18 kDA) is a high-affinity cholesterol-binding protein that is integrally involved in cholesterol transfer from intracellular stores into mitochondria, the rate-determining step in steroid formation. Previous studies have shown that TSPO drug ligands are able to activate steroid production by MA-10 mouse Leydig tumor cells and by mitochondria isolated from steroidogenic cells. We hypothesized herein that the direct, pharmacological activation of TSPO might induce aged Leydig cells, which are characterized by reduced T production, to produce significantly higher levels of T both in vitro and in vivo. To test this, we first examined the in vitro effects of the TSPO selective and structurally distinct drug ligands N,N-dihexyl-2-(4-fluorophenyl)indole-3-acetamide (FGIN-1-27) and benzodiazepine 4'-chlorodiazepam (Ro5-4864) on steroidogenesis by Leydig cells isolated from aged (21-24 months old) and young adult (3-6 months old) Brown Norway rats. The ligands stimulated Leydig cell T production significantly, and equivalently, in cells of both ages, an effect that was significantly inhibited by the specific TSPO inhibitor 5-androsten-3,17,19-triol (19-Atriol). Additionally, we examined the in vivo effects of administering FGIN-1-27 to young and aged rats. In both cases, serum T levels increased significantly, consistent with the in vitro results. Indeed, serum T levels in aged rats administered FGIN-1-27 were equivalent to T levels in the serum of control young rats. Taken together, these results indicate that although there are reduced amounts of TSPO in aged Leydig cells, its direct activation is able to increase T production. We suggest that this approach might serve as a therapeutic means to increase steroid levels in vivo in cases of primary hypogonadism.
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Affiliation(s)
- J Y Chung
- Department of Biochemistry and Molecular Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21205, USA
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Ude C, Schubert-Zsilavecz M, Wurglics M. Ginkgo biloba Extracts: A Review of the Pharmacokinetics of the Active Ingredients. Clin Pharmacokinet 2013; 52:727-49. [DOI: 10.1007/s40262-013-0074-5] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Lau AJ, Yang G, Rajaraman G, Baucom CC, Chang TKH. Evaluation of Ginkgo biloba extract as an activator of human glucocorticoid receptor. JOURNAL OF ETHNOPHARMACOLOGY 2013; 145:670-675. [PMID: 23220176 DOI: 10.1016/j.jep.2012.11.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 09/26/2012] [Accepted: 11/24/2012] [Indexed: 06/01/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Ginkgo biloba, which is one of the most frequently used herbal medicines, is commonly used in the management of several conditions, including memory impairment. Previously, it was reported to decrease the expression of peripheral benzodiazepine receptor and the biosynthesis of glucocorticoids, thereby regulating glucocorticoid levels. However, it is not known whether Ginkgo biloba extract regulates the function of the glucocorticoid receptor. AIM OF THE STUDY We determined whether Ginkgo biloba extract and several of its chemical constituents affect the activity of human glucocorticoid receptor (hGR). MATERIALS AND METHODS A hGR-dependent reporter gene assay was conducted in HepG2 human hepatocellular carcinoma cells and hGR target gene expression assays were performed in primary cultures of human hepatocytes. RESULTS Multiple lots and concentrations of the extract and several of its chemical constituents (ginkgolide A, ginkgolide B, ginkgolide C, ginkgolide J, and bilobalide) did not increase hGR activity, as assessed by a cell-based luciferase reporter gene assay. The extract did not influence the expression of hGR target genes, including tyrosine aminotransferase (hTAT), constitutive androstane receptor (hCAR), or pregnane X receptor (hPXR), in primary cultures of human hepatocytes. Moreover, hGR antagonism by mifepristone (also known as RU486) did not attenuate the extent of induction of hCAR- and hPXR-regulated target genes CYP2B6 and CYP3A4 by Ginkgo biloba extract. CONCLUSION Ginkgo biloba extract, ginkgolide A, ginkgolide B, ginkgolide C, ginkgolide J, and bilobalide are not activators of hGR. Furthermore, the extract does not influence the hGR-hCAR or the hGR-hPXR signaling pathway in primary cultures of human hepatocytes.
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Affiliation(s)
- Aik Jiang Lau
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
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Ma L, Wang S, Tai F, Yuan G, Wu R, Liu X, Wei B, Yang X. Effects of bilobalide on anxiety, spatial learning, memory and levels of hippocampal glucocorticoid receptors in male Kunming mice. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2012; 20:89-96. [PMID: 23083816 DOI: 10.1016/j.phymed.2012.09.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 08/03/2012] [Accepted: 09/15/2012] [Indexed: 06/01/2023]
Abstract
With various constituents in ginkgo biloba extract, the detailed internal mechanism underlying a reduction in anxiety and improvements to learning and memory from GBE is not well understood. The present study investigated whether bilobalide, an important constituent in GBE, could affect anxiety, spatial learning and memory in male mice and whether hippocampal glucocorticoid receptor expression is associated with alteration in these behaviors. Mice were treated orally either with sesame seed oil or one of three dosages of bilobalide (2.5, 5.0 and 10.0 mg/kg) daily until testing. A series of behavioral tests showed that repeated bilobalide treatment decreased levels of anxiety-like behavior and increased locomotor activity in open field and elevated plus maze tests. Treatment with bilobalide also shortened the time taken to find the platform in a Morris water-maze test. Mice exposed to bilobalide showed higher and dose-dependent levels of glucocorticoid receptor expression in the hippocampus. These results suggest that bilobalide reduces anxiety levels and enhances spatial learning and memory, possibly through an increase in hippocampal glucocorticoid receptor expression. This finding sheds light on the mechanisms underlying the effect of ginkgo biloba extract on behavior and also provides an important candidate drug in treatment of anxiety, depression, hypomnesia and amnesia.
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Affiliation(s)
- Leige Ma
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China
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Batarseh A, Papadopoulos V. Regulation of translocator protein 18 kDa (TSPO) expression in health and disease states. Mol Cell Endocrinol 2010; 327:1-12. [PMID: 20600583 PMCID: PMC2922062 DOI: 10.1016/j.mce.2010.06.013] [Citation(s) in RCA: 215] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 06/17/2010] [Indexed: 01/12/2023]
Abstract
Translocator protein (TSPO) is an 18 kDa high affinity cholesterol- and drug-binding protein found primarily in the outer mitochondrial membrane. Although TSPO is found in many tissue types, it is expressed at the highest levels under normal conditions in tissues that synthesize steroids. TSPO has been associated with cholesterol import into mitochondria, a key function in steroidogenesis, and directly or indirectly with multiple other cellular functions including apoptosis, cell proliferation, differentiation, anion transport, porphyrin transport, heme synthesis, and regulation of mitochondrial function. Aberrant expression of TSPO has been linked to multiple diseases, including cancer, brain injury, neurodegeneration, and ischemia-reperfusion injury. There has been an effort during the last decade to understand the mechanisms regulating tissue- and disease-specific TSPO expression and to identify pharmacological means to control its expression. This review focuses on the current knowledge regarding the chemicals, hormones, and molecular mechanisms regulating Tspo gene expression under physiological conditions in a tissue- and disease-specific manner. The results described here provide evidence that the PKCepsilon-ERK1/2-AP-1/STAT3 signal transduction pathway is the primary regulator of Tspo gene expression in normal and pathological tissues expressing high levels of TSPO.
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Affiliation(s)
- Amani Batarseh
- Department of Biochemistry and Molecular and Cell Biology, Georgetown University Medical Center, Washington, D.C. 20057, USA
- The Research Institute of the McGill University Health Centre and the Department of Medicine, Biochemistry, McGill University, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Canada
| | - Vassilios Papadopoulos
- Department of Biochemistry and Molecular and Cell Biology, Georgetown University Medical Center, Washington, D.C. 20057, USA
- The Research Institute of the McGill University Health Centre and the Department of Medicine, Biochemistry, McGill University, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Canada
- Department of Pharmacology and Therapeutics, McGill University, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Canada
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Batarseh A, Li J, Papadopoulos V. Protein kinase C epsilon regulation of translocator protein (18 kDa) Tspo gene expression is mediated through a MAPK pathway targeting STAT3 and c-Jun transcription factors. Biochemistry 2010; 49:4766-78. [PMID: 20469933 DOI: 10.1021/bi100020e] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Translocator protein TSPO is an 18 kDa protein implicated in numerous cell functions and is highly expressed in secretory and glandular tissues, especially in steroidogenic cells. TSPO expression is altered in pathological conditions such as certain cancers and neurological diseases. In search of the factors regulating Tspo expression, we recently showed that high levels of TSPO in steroidogenic cells may be due to high constitutive expression of protein kinase Cepsilon (PKCepsilon), while phorbol 12-myristate 13-acetate (PMA) activation of PKCepsilon drives inducible TSPO expression in nonsteroidogenic cells, likely through activator protein 1 (AP1). In this study, we aimed to identify the signal transduction pathway through which PKCepsilon regulates Tspo gene expression. The MEK1/2 specific inhibitor U0126, but not NFkappaB inhibitors, reduced basal Tspo promoter activity in TSPO-rich steroidogenic cells (MA-10 Leydig), as well as basal and PMA-induced Tspo promoter levels in TSPO-poor nonsteroidogenic cells (NIH-3T3 fibroblasts). AP1 and signal transducer and activation of transcription 3 (STAT3) have binding sites in the Tspo promoter and are downstream targets of PKCepsilon and MAPK (Raf-1-ERK1/2) pathways. PKCepsilon overexpression induced STAT3 phosphorylation in NIH-3T3 cells, while PKCepsilon knockdown reduced STAT3 and c-Jun phosphorylation in Leydig cells. MEK1/2, ERK2, c-Jun, and STAT3 knockdown reduced Tspo mRNA and protein levels in Leydig cells. Additionally, Raf-1 reduced Tspo mRNA levels in the same cells. MEK1/2, c-Jun, and STAT3 knockdown also reduced basal as well as PMA-induced Tspo mRNA levels in NIH-3T3 cells. Together, these results demonstrate that PKCepsilon regulates Tspo gene expression through a MAPK (Raf-1-MEK1/2-ERK1/2) signal transduction pathway, acting at least in part through c-Jun and STAT3 transcription factors.
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Affiliation(s)
- Amani Batarseh
- Department of Biochemistry and Molecular and Cell Biology, Georgetown University Medical Center, Washington, DC 20057, USA
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Ginkgo biloba extract in Alzheimer's disease: from action mechanisms to medical practice. Int J Mol Sci 2010; 11:107-23. [PMID: 20162004 PMCID: PMC2820992 DOI: 10.3390/ijms11010107] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Revised: 12/31/2009] [Accepted: 01/01/2010] [Indexed: 12/15/2022] Open
Abstract
Standardized extract from the leaves of the Ginkgo biloba tree, labeled EGb761, is one of the most popular herbal supplements. Numerous preclinical studies have shown the neuroprotective effects of EGb761 and support the notion that it may be effective in the treatment and prevention of neurodegenerative disorders such as Alzheimer’s disease (AD). Despite the preclinical promise, the clinical efficacy of this drug remains elusive. In this review, possible mechanisms underlying neuroprotective actions of EGb761 are described in detail, together with a brief discussion of the problem of studying this herb clinically to verify its efficacy in the treatment and prevention of AD. Moreover, various parameters e.g., the dosage and the permeability of the blood brain barrier (BBB), impacting the outcome of the clinical effectiveness of the extract are also discussed. Overall, the findings summarized in this review suggest that, a better understanding of the neuroprotective mechanisms of EGb761 may contribute to better understanding of the effectiveness and complexity of this herb and may also be helpful for design of therapeutic strategies in future clinical practice. Therefore, in future clinical studies, different factors that could interfere with the effect of EGb761 should be considered.
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Gingkoselect alleviates chronic corticosterone-induced spatial memory deficits in rats. Fitoterapia 2009; 81:25-9. [PMID: 19619621 DOI: 10.1016/j.fitote.2009.06.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Accepted: 06/29/2009] [Indexed: 11/21/2022]
Abstract
The preventive effects of Gingkoselect (100 mg/kg/day, orally, 21 days) on spatial memory deficits induced by a chronic restraint stress (2 h daily, 21 days) or chronic corticosterone treatment (5 mg/kg, subcutaneously, 21 days) were investigated using the Barnes maze. Chronic corticosterone, but not chronic stress, impaired spatial memory, as shown by increased latency to finding escape tunnel in the maze. Gingkoselect normalized cognitive deficits in rats chronically treated with corticosterone, and improved memory above the control levels in the chronically stressed rats.
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Shi C, Zhao L, Zhu B, Li Q, Yew DT, Yao Z, Xu J. Dosage effects of EGb761 on hydrogen peroxide-induced cell death in SH-SY5Y cells. Chem Biol Interact 2009; 180:389-97. [PMID: 19414004 DOI: 10.1016/j.cbi.2009.04.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Revised: 04/24/2009] [Accepted: 04/27/2009] [Indexed: 01/03/2023]
Abstract
Standardized extract from the leaves of the Ginkgo biloba tree, labeled EGb761, is one of the most popular herbal supplements, taken for its multivalent properties. In this study, dosage effects of EGb761 on hydrogen peroxide (H(2)O(2))-induced apoptosis of human neuroblastoma SH-SY5Y cells were investigated. It was found that H(2)O(2)-induced apoptotic cell death in SH-SY5Y cells, which was revealed in DNA fragmentation, mitochondrial membrane potential depolarization, and activation of Akt, c-Jun N-terminal kinases (JNK) and caspase 3. Low doses of EGb761 (50-100 microg/ml) inhibited H(2)O(2)-induced cell apoptosis via inactivation of Akt, JNK and caspase 3 while high doses of EGb761 (250-500 microg/ml) enhanced H(2)O(2) toxicities via inactivation of Akt and enhancement of activation of JNK and caspase 3. Additional experiments revealed that H(2)O(2) decreased intracellular GSH content, which was also inhibited by low concentrations of EGb761 but enhanced after high concentrations of EGb761 treatment. This further suggests to us that dosage effects of EGb761 on apoptotic signaling proteins may be correlated with regulation of cell redox state. Therefore, treatment dosage may be one of the vital factors that determine the specific action of EGb761 on oxidative stress-induced cell apoptosis. To understand the mechanisms of dosage effects of EGb761 may have important clinical implications.
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Affiliation(s)
- Chun Shi
- Department of Anatomy, Zhongshan School of Medicine, Sun Yat-Sen University Guangzhou, Guangdong 510080, China
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Batarseh A, Giatzakis C, Papadopoulos V. Phorbol-12-myristate 13-acetate acting through protein kinase Cepsilon induces translocator protein (18-kDa) TSPO gene expression. Biochemistry 2009; 47:12886-99. [PMID: 18975922 DOI: 10.1021/bi8012643] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Translocator protein (TSPO) is an 18-kDa cholesterol-binding protein that is expressed at high levels in steroid synthesizing and several cancer cells where it is involved in steroidogenesis and cell proliferation, respectively. The factors regulating Tspo expression are unknown. We analyzed Tspo transcriptional responses to the tumor promoter, phorbol-12-myristate 13-acetate (PMA), in cells with varying TSPO levels. PMA induced Tspo promoter activity and Tspo mRNA levels in TSPO-poor nonsteroidogenic cells (NIH-3T3 fibroblasts and COS-7 kidney) but not in TSPO-rich steroidogenic cells (MA-10 Leydig) with high basal Tspo transcriptional activity. The stimulatory effect of PMA was mediated by an 805-515-bp region upstream of the transcription start site. Electrophoretic mobility shift assay (EMSA) revealed that PMA induced binding of c-jun and GA-binding protein transcription factor (GABP-alpha) to their respective activator protein 1 (AP1) and v-ets erythroblastosis virus E26 oncogene homologue (Ets) sites in this region. Protein kinase C (PKC)-specific inhibitors blocked PMA induction of Tspo promoter activity with an inhibition profile suggestive of involvement of PKCepsilon. PKCepsilon expression correlated with TSPO content in the three cell lines. In NIH-3T3 cells, PKCepsilon overexpression induced Tspo promoter activity and mRNA levels and enhanced PMA-induced up regulation of c-jun and TSPO. In MA-10 cells, a PKCepsilon-specific translocation inhibitor peptide reduced basal Tspo promoter activity. PKCepsilon siRNA pool reduced PKCepsilon and TSPO levels in MA-10 cells indicating a role for PKCepsilon in regulating TSPO expression. Taken together, these data suggest that elevated TSPO expression in steroidogenic cells may be due to high constitutive expression of PKCepsilon that renders them unresponsive to further induction while PMA activation of PKCepsilon drives inducible TSPO expression in nonsteroidogenic cells, likely through AP1 and Ets.
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Affiliation(s)
- Amani Batarseh
- Department of Biochemistry & Molecular and Cell Biology, Georgetown University Medical Center, Washington, DC 20057, USA
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Walesiuk A, Braszko JJ. Preventive action of Ginkgo biloba in stress- and corticosterone-induced impairment of spatial memory in rats. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2009; 16:40-6. [PMID: 17482446 DOI: 10.1016/j.phymed.2007.04.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Accepted: 03/16/2007] [Indexed: 05/15/2023]
Abstract
In this study, we tested preventive effects of a natural medicine the extract of Ginkgo biloba (EGB 761) on post-stress cognitive dysfunction. Exposure to chronic restraint stress in rats and psychosocial stress in humans has been shown to alter cognitive functions such as learning and memory and have been linked to the pathophysiology of mood and anxiety disorders. Our findings indicate that chronic restraint stress impaired egocentric spatial memory as observed in the eight-arm radial maze but it did not alter the allocentric spatial memory in the Morris water maze. In control rats EGB 761 (100mg/kg, orally) improved spatial memory in these two tests. Also, EGB 761 normalized cognitive deficits seen in rats chronically stressed or treated with an 'equivalent' dose of exogenous corticosterone (5mg/kg, subcutaneously). We conclude that, in rats, repeated administration of EGB 761 prevents stress- and corticosterone-induced impairments of spatial memory.
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Affiliation(s)
- Anna Walesiuk
- Department of Clinical Pharmacology, Medical University of Bialystok, Bialystok, Poland
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Chen C, Xia SH, Chen H, Li XH. Therapy for acute pancreatitis with platelet-activating factor receptor antagonists. World J Gastroenterol 2008; 14:4735-8. [PMID: 18720532 PMCID: PMC2739333 DOI: 10.3748/wjg.14.4735] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Acute pancreatitis (AP) causes release of platelet-activating factor (PAF), which induces systemic effects that contribute to circulatory disturbances and multiple organ failure. PAF is a cell surface secretion of bioactive lipid, which could produce physiological and pathological effects by binding to its cell surface receptor called platelet-activating factor receptor (PAF-R). Studies showed that PAF participates in the occurrence and development of AP and administration of platelet-activating factor receptor antagonists (PAF-RAs) could significantly reduce local and systemic events after AP. PAF has also been implicated as a key mediator in the progression of severe AP, which can lead to complications and unacceptably high mortality rates. Several classes of PAF-RA show PAF-RAs significant local and systemic effects on reducing inflammatory changes. As a preventive treatment, PAF-RA could block a series of PAF-mediated inflammatory injury and thus improve the prognosis of AP. This review introduces the important role of PAF-RA in the treatment of AP.
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Hamer M, Owen G, Kloek J. The role of functional foods in the psychobiology of health and disease. Nutr Res Rev 2007; 18:77-88. [DOI: 10.1079/nrr2005103] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AbstractThe effect of psychological stress on health is becoming a serious concern, with figures from the World Health Organization showing that stress-related disorders affect nearly 450 million individuals worldwide. Heightened physiological stress responses and psychosocial factors have been linked to disease pathways such as hypertension and CVD. This has prompted significant interest within the scientific community, public health bodies and industry to employ interventions to control and reduce the impact of stress on health. There is now strong potential for functional foods to offer stress management benefits. Various physiological pathways have been targeted by specific dietary supplements for stress reduction, including the hypothalamic–pituitary–adrenal axis and sympathetic nervous system. Presently there are a number of ingredients, which include vitamin C, milk proteins, a number of herbal extracts (ginkgo biloba, ginseng, kava, valerian and lemon balm), andn-3 fatty acids, that have demonstrated potential stress reactivity-lowering and mood-enhancing effects, although further work is required to substantiate the efficacy in human subjects. Dietary supplements that can alleviate excessive stress responses may play an increasingly important role for the maintenance of health in a stressful environment. However, future research should employ a greater range of measures that will provide stronger evidence to substantiate functional food claims for stress relief.
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Markowitz JS, DeVane CL, Lewis JG, Chavin KD, Wang JS, Donovan JL. Effect ofGinkgo bilobaExtract on Plasma Steroid Concentrations in Healthy Volunteers: A Pilot Study. Pharmacotherapy 2005; 25:1337-40. [PMID: 16185177 DOI: 10.1592/phco.2005.25.10.1337] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
STUDY OBJECTIVE To determine if a standardized ginkgo supplement significantly alters concentrations of circulating androgenic steroids in humans. DESIGN Open-label, fixed-treatment order, crossover study. SETTING University general clinical research center. SUBJECTS Eleven healthy volunteers (six men, five women). INTERVENTION Volunteers received ginkgo biloba 240 mg/day for 14 days. MEASUREMENTS AND MAIN RESULTS Plasma concentrations of cortisol, 11-deoxycortisol, 17alpha-hydroxyprogesterone, testosterone, dihydrotestosterone, dehydroepiandrosterone sulfate, sex hormone-binding globulin, androstenedione, and free testosterone, as well as free androgen index and combined concentrations of androsterone sulfate and epiandrosterone sulfate, were analyzed in all subjects before and after their 14-day course of ginkgo biloba. Ginkgo biloba did not significantly alter endogenous steroid levels compared with baseline values (p < 0.05). CONCLUSION A 14-day oral administration of a widely used, standardized ginkgo extract at a generally advocated dosage of 240 mg/day did not significantly alter concentrations of major circulating steroids in men and women.
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Affiliation(s)
- John S Markowitz
- Department of Pharmaceutical Sciences, Medical University of South Carolina, Children's Research Institute, Charleston, South Carolina 29425, USA.
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Yao ZX, Han Z, Drieu K, Papadopoulos V. Ginkgo biloba extract (Egb 761) inhibits beta-amyloid production by lowering free cholesterol levels. J Nutr Biochem 2005; 15:749-56. [PMID: 15607648 DOI: 10.1016/j.jnutbio.2004.06.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2003] [Revised: 05/15/2004] [Accepted: 06/15/2004] [Indexed: 12/20/2022]
Abstract
Ginkgo biloba extract (EGb 761) can improve cognitive function in patients with Alzheimer's disease, but the molecular mechanisms underlying this effect remain undefined. Because free cholesterol may be involved in the production of beta-amyloid precursor protein and amyloid beta-peptide, key events in the development of Alzheimer's disease, we examined EGb 761 in relation to cholesterol and amyloidogenesis. In aging rats, EGb 761 treatment lowered circulating free cholesterol and inhibited the production of brain beta-amyloid precursor protein and amyloid beta-peptide. Exposure of PC12 cells to EGb 761 decreased the processing of beta-amyloid precursor protein and abolished cholesterol-induced overproduction of this protein. Exposure of human NT2 cells to EGb 761 decreased free cholesterol influx and increased free cholesterol efflux. Our findings indicate that free circulating and intracellular cholesterol levels affect the processing of beta-amyloid precursor protein and amyloidogenesis. Our findings also provide the first demonstration that EGb 761 can influence these mechanisms.
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Affiliation(s)
- Zhi-Xing Yao
- Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, 3900 Reservoir Road, NW, Washington, DC 20057, USA
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Billottet L, Martel S, Culcasi M, Drieu K, Carrupt PA, Pietri S. Influence of lipophilicity and stereochemistry at the C7 position on the cardioprotective and antioxidant effect of ginkgolides during rat heart ischemia and reperfusion. Drug Dev Res 2005. [DOI: 10.1002/ddr.10424] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Rai D, Bhatia G, Sen T, Palit G. Anti-stress effects of Ginkgo biloba and Panax ginseng: a comparative study. J Pharmacol Sci 2004; 93:458-64. [PMID: 14737017 DOI: 10.1254/jphs.93.458] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Stress is a global menace fortified by the advancement of industrialization. Failure of stress management is due to lack of proper evaluation of anti-stress products. We explored the anti-stress potential of the Ginkgo biloba (G. biloba, 30 mg/kg, p.o.) and compared it with that of Panax ginseng (P. ginseng, 100 mg/kg, p.o.) against acute stress (AS) and chronic stress (CS) models in rats. Immediately after AS and CS, the rats were sacrificed, and adrenal glands and stomach were dissected out for weight determination and scoring of the ulcer index (UI), respectively, as well as changes in biochemical parameters like plasma glucose (GL), triglycerides (TG), cholesterol (CL), creatine kinase (CK), and serum corticosterone (CORT) were also estimated. AS significantly increased UI, adrenal gland weight (AGW), GL, CK activity, and CORT, whereas G. biloba significantly reduced them. P. ginseng significantly reverted GL and CK activity. In CS, a significant increase was found in the UI, AGW, CK activity, and CORT with a decrease in the level of CL and TG. G. biloba did not produce any significant effect on CS-induced alterations. P. ginseng reduced the UI, AGW, plasma GL, TG, CK activity, and CORT level significantly. From the above study, G. biloba is more effective in AS, whereas for CS, P. ginseng will be a better option. Hence these extracts possess significant anti-stress properties and can be used for the treatment of stress-induced disorders.
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Affiliation(s)
- Deepak Rai
- Division of Pharmacology, Central Drug Research Institute, Lucknow, India
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Giatzakis C, Papadopoulos V. Differential utilization of the promoter of peripheral-type benzodiazepine receptor by steroidogenic versus nonsteroidogenic cell lines and the role of Sp1 and Sp3 in the regulation of basal activity. Endocrinology 2004; 145:1113-23. [PMID: 14630713 DOI: 10.1210/en.2003-1330] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The peripheral-type benzodiazepine receptor (PBR) is involved in many cellular functions, including steroidogenesis, oxidative processes, cellular proliferation, and apoptosis. Secretory and glandular tissues, especially steroid hormone-producing cells, are particularly rich in PBR. To understand the mechanisms of PBR expression and regulation, we established an mRNA expression profile in mouse tissues and cell lines and subsequently mapped the transcription start site and characterized the promoter of the gene. Our findings indicate that PBR tissue mRNA levels are relatively high in kidney, spleen, muscle, lung, adrenal gland, thymus, and stomach; are intermediate in pancreas, uterus, prostate, heart, and testis; and are low in brain and liver. Relatively high levels of PBR mRNA were also observed in the steroid-synthesizing MA-10 mouse Leydig tumor cells compared with adrenocortical Y1 mouse cells and nonsteroidogenic NIH-3T3 mouse fibroblasts, although PBR protein levels were much higher in both steroidogenic cells compared with fibroblasts. Transcription was initiated primarily at an adenine nucleotide 61 nucleotides upstream of the translation start site, but internal initiation was also observed. A 2.7-kb fragment of the mouse PBR promoter was cloned and sequenced. Sequence analysis revealed the absence of TATA or CCAAT boxes, but the presence of many putative transcription factor-binding sites, including Sp1/Sp3, AP2, Ik2, AP1, SOX, GATA, and SRY. Functional characterization revealed that two Sp1/Sp3 sites in the proximal promoter are important for basal activity in all cell lines tested and that the steroidogenic MA-10 and Y1 cells use different areas of the promoter compared with nonsteroidogenic NIH-3T3 cells.
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Affiliation(s)
- Christoforos Giatzakis
- Department of Cell Biology, Georgetown University Medical Center, Washington, DC 20057, USA
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