1
|
Chen Q, Song Q, Yang X, Han H, Zhang X, Liao Y, Zhang W, Ye J, Cheng S, Xu F. Characterization of a novel levopimaradiene synthase gene responsible for the biosynthesis of terpene trilactones in Ginkgo biloba. PLANT SIGNALING & BEHAVIOR 2021; 16:1885906. [PMID: 33570442 PMCID: PMC7971208 DOI: 10.1080/15592324.2021.1885906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/31/2021] [Accepted: 02/01/2021] [Indexed: 06/12/2023]
Abstract
Terpene trilactones (TTLs) are the main medicinal compounds of Ginkgo biloba. Levopimaradiene synthase (LPS) is the crucial enzyme that catalyzes TTLs biosynthesis in G. biloba. In this study, a novel LPS gene (designated as GbLPS2) was cloned from G. biloba leaves. The open reading frame of GbLPS2 gene was 2520 bp in length, encoding a predicted polypeptide of 840 amino acids. Phylogenetic analysis revealed that the GbLPS2 was highly homologous with reported LPS proteins in other plants. On the basis of the genomic DNA (gDNA) template, a 4308 bp gDNA sequence of GbLPS2 and a 913 bp promoter sequence were amplified. Cis-acting elements in promoter analysis indicated that GbLPS2 could be regulated by methyl jasmonate (MeJA) and abscisic acid (ABA). Tissue-specific expression analysis revealed that GbLPS2 was mainly expressed in roots and ovulate strobilus. MeJA treatment could significantly induce the expression level of GbLPS2 and increase the content of TTLs. This study illustrates the structure and the tissue-specific expression pattern of GbLPS2 and demonstrates that exogenous hormones regulated the expression of GbLPS2 and TTL content in G. biloba. Our results provide a target gene for the enhancement of TTL content in G. biloba via genetic engineering.
Collapse
Affiliation(s)
- Qiangwen Chen
- College of Horticulture and Gardening, Yangtze University, Jingzhou, Hubei, China
| | - Qiling Song
- College of Horticulture and Gardening, Yangtze University, Jingzhou, Hubei, China
- Key Laboratory of Cultivation and Protection for Non-Wood Forest Trees of the Ministry of Education and the Key Laboratory of Non-Wood Forest Products of Forestry Ministry, Central South University of Forestry and Technology, Changsha, Hunan, China
| | - Xiaoyan Yang
- College of Horticulture and Gardening, Yangtze University, Jingzhou, Hubei, China
| | - Huan Han
- College of Horticulture and Gardening, Yangtze University, Jingzhou, Hubei, China
| | - Xian Zhang
- College of Horticulture and Gardening, Yangtze University, Jingzhou, Hubei, China
| | - Yongling Liao
- College of Horticulture and Gardening, Yangtze University, Jingzhou, Hubei, China
| | - Weiwei Zhang
- College of Horticulture and Gardening, Yangtze University, Jingzhou, Hubei, China
| | - Jiabao Ye
- College of Horticulture and Gardening, Yangtze University, Jingzhou, Hubei, China
| | - Shuiyuan Cheng
- National R&D for Se-rich Agricultural Products Processing Technology, Wuhan Polytechnic University, Wuhan, China
| | - Feng Xu
- College of Horticulture and Gardening, Yangtze University, Jingzhou, Hubei, China
| |
Collapse
|
2
|
Chen Q, Yan J, Meng X, Xu F, Zhang W, Liao Y, Qu J. Molecular Cloning, Characterization, and Functional Analysis of Acetyl-CoA C-Acetyltransferase and Mevalonate Kinase Genes Involved in Terpene Trilactone Biosynthesis from Ginkgo biloba. Molecules 2017; 22:E74. [PMID: 28045448 PMCID: PMC6155782 DOI: 10.3390/molecules22010074] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 12/20/2016] [Accepted: 12/27/2016] [Indexed: 12/15/2022] Open
Abstract
Ginkgolides and bilobalide, collectively termed terpene trilactones (TTLs), are terpenoids that form the main active substance of Ginkgo biloba. Terpenoids in the mevalonate (MVA) biosynthetic pathway include acetyl-CoA C-acetyltransferase (AACT) and mevalonate kinase (MVK) as core enzymes. In this study, two full-length (cDNAs) encoding AACT (GbAACT, GenBank Accession No. KX904942) and MVK (GbMVK, GenBank Accession No. KX904944) were cloned from G. biloba. The deduced GbAACT and GbMVK proteins contain 404 and 396 amino acids with the corresponding open-reading frame (ORF) sizes of 1215 bp and 1194 bp, respectively. Tissue expression pattern analysis revealed that GbAACT was highly expressed in ginkgo fruits and leaves, and GbMVK was highly expressed in leaves and roots. The functional complementation of GbAACT in AACT-deficient Saccharomyces cerevisiae strain Δerg10 and GbMVK in MVK-deficient strain Δerg12 confirmed that GbAACT mediated the conversion of mevalonate acetyl-CoA to acetoacetyl-CoA and GbMVK mediated the conversion of mevalonate to mevalonate phosphate. This observation indicated that GbAACT and GbMVK are functional genes in the cytosolic mevalonate (MVA) biosynthesis pathway. After G. biloba seedlings were treated with methyl jasmonate and salicylic acid, the expression levels of GbAACT and GbMVK increased, and TTL production was enhanced. The cloning, characterization, expression and functional analysis of GbAACT and GbMVK will be helpful to understand more about the role of these two genes involved in TTL biosynthesis.
Collapse
Affiliation(s)
- Qiangwen Chen
- College of Horticulture and Gardening, Yangtze University, Jingzhou 434025, Hubei, China.
| | - Jiaping Yan
- College of Horticulture and Gardening, Yangtze University, Jingzhou 434025, Hubei, China.
| | - Xiangxiang Meng
- College of Horticulture and Gardening, Yangtze University, Jingzhou 434025, Hubei, China.
| | - Feng Xu
- College of Horticulture and Gardening, Yangtze University, Jingzhou 434025, Hubei, China.
| | - Weiwei Zhang
- College of Horticulture and Gardening, Yangtze University, Jingzhou 434025, Hubei, China.
| | - Yongling Liao
- College of Horticulture and Gardening, Yangtze University, Jingzhou 434025, Hubei, China.
| | - Jinwang Qu
- College of Horticulture and Gardening, Yangtze University, Jingzhou 434025, Hubei, China.
| |
Collapse
|
3
|
Kim JH, Lee KI, Chang YJ, Kim SU. Developmental pattern of Ginkgo biloba levopimaradiene synthase (GbLPS) as probed by promoter analysis in Arabidopsis thaliana. PLANT CELL REPORTS 2012; 31:1119-27. [PMID: 22311479 DOI: 10.1007/s00299-012-1232-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 01/19/2012] [Accepted: 01/24/2012] [Indexed: 05/12/2023]
Abstract
Levopimaradiene synthase (GbLPS) of Ginkgo biloba catalyzes the first committed step in ginkgolide biosynthesis by converting geranylgeranyl diphosphate into levopimaradiene, which subsequently undergoes complex oxidation step and rearrangement of carbon skeleton, leading to formation of ginkgolides. To assess the organ-specificity and developmental characteristics of GbLPS expression, the GbLPS promoter-driven GUS expression in transgenic Arabidopsis was studied. Histological analysis of the transgenic Arabidopsis plant showed that the GUS accumulation was mainly localized in the epidermis of leaves, phloem of the shoots, ovaries and stamens of flowers, and vasculature of roots. These observations correlate with the occurrence of LPS transcripts in roots and male strobili of G. biloba. Treatment of methyl jasmonate on the transformant exhibited significant upregulation of the reporter gene in the roots with little change in leaves and flowers. The present findings support biosynthesis of ginkgolide in the roots of Ginkgo plant and suggest translocation occurs through the phloem.
Collapse
Affiliation(s)
- Jin-Hee Kim
- Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Republic of Korea
| | | | | | | |
Collapse
|
4
|
Liao Z, Chen M, Gong Y, Guo L, Tan Q, Feng X, Sun X, Tan F, Tang K. A New Geranylgeranyl Diphosphate Synthase Gene fromGinkgo biloba, which Intermediates the Biosynthesis of the Key Precursor for Ginkgolides. ACTA ACUST UNITED AC 2009; 15:153-8. [PMID: 15352294 DOI: 10.1080/10425170410001667348] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Geranylgeranyl diphosphate synthase (GGPPS, EC: 2.5.1.29) catalyzes the biosynthesis of geranylgeranyl diphosphate (GGPP), which is a key precursor for ginkgolide biosynthesis. Here we reported for the first time the cloning of a new full-length cDNA encoding GGPPS from the living fossil plant Ginkgo biloba. The full-length cDNA encoding G. biloba GGPPS (designated as GbGGPPS) was 1657bp long and contained a 1176bp open reading frame encoding a 391 amino acid protein. Comparative analysis showed that GbGGPPS possessed a 79 amino acid transit peptide at its N-terminal, which directed GbGGPPS to target to the plastids. Bioinformatic analysis revealed that GbGGPPS was a member of polyprenyltransferases with two highly conserved aspartate-rich motifs like other plant GGPPSs. Phylogenetic tree analysis indicated that plant GGPPSs could be classified into two groups, angiosperm and gymnosperm GGPPSs, while GbGGPPS had closer relationship with gymnosperm plant GGPPSs.
Collapse
Affiliation(s)
- Zhihua Liao
- Institute of Genetics, School of Life Sciences, Morgan-Tan International Center for Life Sciences, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, Fudan University, Shanghai 200433, People's Republic of China
| | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Gao S, Lin J, Liu X, Deng Z, Li Y, Sun X, Tang K. Molecular cloning, characterization and functional analysis of a 2C-methyl- D-erythritol 2, 4-cyclodiphosphate synthase gene from ginkgo biloba. BMB Rep 2006; 39:502-10. [PMID: 17002869 DOI: 10.5483/bmbrep.2006.39.5.502] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
2C-methyl-D-erythritol 2, 4-cyclodiphosphate synthase (MECPS, EC: 4.6.1.12) is the fifth enzyme of the non-mevalonate terpenoid pathway for isopentenyl diphosphate biosynthesis and is involved in the methylerythritol phosphate (MEP) pathway for ginkgolide biosynthesis. The full-length mecps cDNA sequence (designated as Gbmecps) was cloned and characterized for the first time from gymnosperm plant species, Ginkgo biloba, using RACE (rapid amplification of cDNA ends) technique. The full-length cDNA of Gbmecps was 874 bp containing a 720 bp open reading frame (ORF) encoding a peptide of 239 amino acids with a calculated molecular mass of 26.03 kDa and an isoelectric point of 8.83. Comparative and bioinformatic analyses revealed that GbMECPS showed extensive homology with MECPSs from other species and contained conserved residues owned by the MECPS protein family. Phylogenetic analysis indicated that GbMECPS was more ancient than other plant MECPSs. Tissue expression pattern analysis indicated that GbMECPS expressed the highest in roots, followed by in leaves, and the lowest in seeds. The color complementation assay indicated that GbMECPS could accelerate the accumulation of beta-carotene. The cloning, characterization and functional analysis of GbMECPS will be helpful to understand more about the role of MECPS involved in the ginkgolides biosynthesis at the molecular level.
Collapse
Affiliation(s)
- Shi Gao
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Morgan-Tan International Center for Life Sciences, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, Fudan University, Shanghai 200433, China
| | | | | | | | | | | | | |
Collapse
|
6
|
Gong Y, Liao Z, Chen M, Zuo K, Guo L, Tan Q, Huang Z, Kai G, Sun X, Tan F, Tang K. Molecular cloning and characterization of a 1-deoxy-D-xylulose 5-phosphate reductoisomerase gene from Ginkgo biloba. ACTA ACUST UNITED AC 2006; 16:111-20. [PMID: 16147862 DOI: 10.1080/10425170500058869] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
1-deoxy-D-xylulose 5-phosphate (DXP) reductoisomerase (DXR, EC: 1.1.1.267) is the second enzyme of the non-mevalonate terpenoid pathway for isopentenyl diphosphate biosynthesis and actually catalyzes a committed step of the methylerythritol phosphate (MEP) pathway for ginkgolide biosynthesis. The full-length DXR cDNA sequence (GenBank accession number: AY443101) was cloned and characterized for the first time from gymnosperm plant species, Ginkgo biloba, using rapid amplification of cDNA ends (RACE) technique. The full-length cDNA of GbDXR was 1720 bp containing a 1431 bp open reading frame (ORF) encoding a peptide of 477 amino acids with a calculated molecular mass of 52 kDa and an isoelectric point of 6.58. Comparative and bioinformatic analyses revealed that GbDXR showed extensive homology with DXRs from other plant species and contained a conserved transit peptide for plastids, an extended Pro-rich region and a highly conserved NADPH binding motif in its N-terminal region owned by all plant DXRs. Phylogenetic analysis indicated that GbDXR was more ancient than other plant DXRs. Tissue expression pattern analysis indicated that GbDXR expressed in all tissues including roots, stems, leaves, pericarps and seeds and lower transcription level was observed in leaves of G. biloba than that of other tissues. The cloning and characterization of GbDXR will be helpful to understand more about the role of DXR involved in the ginkgolides biosynthesis at the molecular level.
Collapse
Affiliation(s)
- Yifu Gong
- Plant Biotechnology Research Center, School of Agriculture and Biology, School of Life Science and Technology, Shanghai Jiao Tong University, Shanghai 200030, People's Republic of China
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Hua L, Guangji W, Hao L, Minwen H, Haitang X, Chenrong H, Jianguo S, Tian L. Sensitive and selective liquid chromatography–electrospray ionization mass spectrometry analysis of ginkgolide B in dog plasma. J Pharm Biomed Anal 2006; 40:88-94. [PMID: 16023818 DOI: 10.1016/j.jpba.2005.06.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2005] [Revised: 05/26/2005] [Accepted: 06/02/2005] [Indexed: 10/25/2022]
Abstract
As an important active constituent of Ginkgo biloba extract, ginkoglide B is a highly selective and competitive PAF receptor antagonist which has been widely used in clinical applications. A novel high-performance liquid chromatography-electrospray ionization mass spectromentry (LC-ESI-MS) method was developed for the determination of ginkgolide B in dog plasma. After liquid/liquid extraction with ether and high-performance liquid chromatography (HPLC) gradient separation with 0.01% of ammonia water (v/v)-methanol as the mobile phase, the deprotonized anions [M-H](-1) at m/z 423 of ginkoglide B, and [M-H](-1) at m/z 492 of internal standard (IS) glibenclamide were analyzed by LC-ESI-MS in selected ion monitoring (SIM) mode. Chromatographic separation was achieved in less than 9 min and calibration curve was linear over a concentration range of 0.1-20 ng/ml. The described assay method was successfully applied to the pre-clinical pharmacokinetic study of ginkoglide B. After intragastric administration of ginkgolide B to beagle dogs, C(max) and T(max) of ginkgolide B were 43.8 +/- 6.24 ng/ml and 0.5 h, respectively, and the elimination half-life (t(1/2)) was 2.85 +/- 0.54 h.
Collapse
Affiliation(s)
- Lv Hua
- Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Schepmann HG, Pang J, Matsuda SP. Cloning and characterization of Ginkgo biloba levopimaradiene synthase which catalyzes the first committed step in ginkgolide biosynthesis. Arch Biochem Biophys 2001; 392:263-9. [PMID: 11488601 DOI: 10.1006/abbi.2001.2438] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Levopimaradiene synthase, which catalyzes the initial cyclization step in ginkgolide biosynthesis, was cloned and functionally characterized. A Ginkgo biloba cDNA library was prepared from seedling roots and a probe was amplified using primers corresponding to conserved gymnosperm terpene synthase sequences. Colony hybridization and rapid amplification of cDNA ends yielded a full-length clone encoding a predicted protein (873 amino acids, 100,289 Da) similar to known gymnosperm diterpene synthases. The sequence includes a putative N-terminal plastid transit peptide and three aspartate-rich regions. The full-length protein expressed in Escherichia coli cyclized geranylgeranyl diphosphate to levopimaradiene, which was identical to a synthetic standard by GC/MS analysis. Removing 60 or 79 N-terminal residues increased levopimaradiene production, but a 128-residue N-terminal deletion lacked detectable activity. This is the first cloned ginkgolide biosynthetic gene and the first in vitro observation of an isolated ginkgolide biosynthetic enzyme.
Collapse
Affiliation(s)
- H G Schepmann
- Department of Chemistry, Rice University, Houston, Texas 77005, USA
| | | | | |
Collapse
|
9
|
Liras A, Catalán RE, Martínez AM. Synergistic effect of endothelin-1 and serotonin in rabbit platelets: effect on tyrosine phosphorylation. Thromb Res 2000; 100:325-31. [PMID: 11113276 DOI: 10.1016/s0049-3848(00)00328-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- A Liras
- Departamento de Biología Molecular/Centro de Biología Molecular, Severo Ochoa (CSIC/UAM) Universidad Autónoma de Madrid, ES-28049, Madrid, Spain
| | | | | |
Collapse
|
10
|
Abstract
Platelet-activating factor (PAF) is a phospholipid synthesized in a variety of cells throughout the body. Platelet-activating factor has been identified in the CNS and has a number of diverse physiological and pathological functions. It has been shown to be a modulator of many CNS processes, ranging from long-term potentiation (LTP) to neuronal differentiation. Excessive levels of PAF appear to play an important role in neuronal cell injury, such as that resulting from ischaemia, inflammation, human immunodeficiency syndrome (HIV) and meningitis. The beneficial effects of PAF receptor antagonists are many and give rise to possible therapeutic strategies for neurotrauma.
Collapse
Affiliation(s)
- K M Maclennan
- Department of Pharmacology, School of Medical Sciences, University of Otago Medical School, Dunedin, New Zealand
| | | | | |
Collapse
|
11
|
Hershkowitz M, Adunsky A. Binding of platelet-activating factor to platelets of Alzheimer's disease and multiinfarct dementia patients. Neurobiol Aging 1996; 17:865-8. [PMID: 9363797 DOI: 10.1016/s0197-4580(96)00073-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The binding of 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine (platelet-activating factor, PAF) to platelets was studied in 22 patients with probable Alzheimer's disease (AD), 11 with multi-infarct dementia (MID), 22 age-matched normal old controls, and 20 young subjects. The results showed a significantly lower degree of PAF binding to platelets of AD and MID patients than in those of the old controls and young subjects (133.3 +/- 8.5, and 123.4 +/- 16.5 vs. 202.3 +/- 11.6 and 206.7 +/- 17.3 receptors/cell, respectively; p < 0.01). These differences were due to reduced Bmax, while Kd remained unchanged. No significant difference was observed between the PAF binding to platelets of AD and MID patients nor between that of old and young controls. No correlation was found between age and binding in the various elderly groups. However, a significant correlation was found between PAF binding and degree of cognitive impairment in the AD patients. This is the first evidence to support a possible involvement of PAF in dementing disorders.
Collapse
Affiliation(s)
- M Hershkowitz
- The Dementia Clinic, Department of Geriatric Rehabilitation, Chaim Sheba Medical Center, Tel-Hashomer, Israel
| | | |
Collapse
|
12
|
Balsa D, Merlos M, Giral M, Ferrando R, García-Rafanell J, Forn J. Characterization of [3H]apafant binding to PAF receptor on rabbit platelet membranes: a comparison of a microplate filtration system and a standard method. J Pharmacol Toxicol Methods 1996; 36:53-62. [PMID: 8872920 DOI: 10.1016/1056-8719(96)00074-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This article describes the application of a Microplate Filtration System (MFS) to a binding assay, with the results being compared to those obtained with a conventional 24-Well Filtration Manifold (24WFM). The data reported here characterize the PAF receptor on rabbit platelet membranes using [3H]apafant. The results showed that [3H]apafant labelled a homogenous population of high-affinity binding sites in a concentration-dependent manner. Binding was very specific, saturable, reversible, and proportional to receptor concentration. [3H]Apafant interacted with membranes in an apparently competitive manner, with pseudo-Hill coefficients not significantly different from unity, thus indicating that apafant did not interact cooperatively at these binding sites. A number of PAF antagonists (apafant, lexipafant, BN-52021, SCH-37370, SR-27417, UR-12670) inhibited [3H]apafant binding with slopes near unity and with a rank order of potency in good agreement with their ability to inhibit PAF-induced rabbit platelet aggregation, suggesting that the sites labelled are functional PAF receptors. C18-PAF also competed with [3H]apafant for the receptor, but yielded biphasic inhibition curves which could be resolved into high- and low-affinity components. No significant differences were found either in the equilibrium binding parameters or in the PAF antagonists affinities obtained with the 24WFM and the MFS. The use of the latter system improved sample handling efficiency and shortened overall labor time, thus representing a more suitable way to perform receptor binding assays.
Collapse
Affiliation(s)
- D Balsa
- Department of Pharmacology, J. Uriach & Cía., Barcelona, Spain
| | | | | | | | | | | |
Collapse
|
13
|
Giral M, Balsa D, Ferrando R, Merlos M, Garcia-Rafanell J, Forn J. Effects of UR-12633, a new antagonist of platelet-activating factor, in rodent models of endotoxic shock. Br J Pharmacol 1996; 118:1223-31. [PMID: 8818347 PMCID: PMC1909590 DOI: 10.1111/j.1476-5381.1996.tb15527.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
1. The effects of the selective and potent novel platelet-activating factor (PAF) antagonist, UR-12633 (1-(3,3-diphenylpropionyl)-4-(3-pyridylcyanomethyl)piperidin e) on several markers of endotoxic shock syndrome were evaluated in rats and mice. 2. UR-12633, administered 60 min after E. coli lipopolysaccharide (LPS), reversed the LPS-induced sustained hypotension in rats at doses of 0.01 to 1 mg kg-1, i.v. The reference compound WEB-2086 (1 mg kg-1) also reversed the LPS-induced hypotension. UR-12633 (1 mg kg-1), administered 10 min before LPS, almost fully inhibited sustained hypotension. The immediate hypotension (within 1 min) caused by LPS was not prevented by either UR-12633 or WEB-2086. 3. Pretreatment with 10 mg kg-1, i.v. of either UR-12633 or WEB-2086 inhibited the increase in disseminated intravascular coagulation markers, such as activated partial thromboplastin time (55 and 74% inhibition, respectively), and prothrombin time (22 and 72% inhibition) and prevented the decrease in plasma fibrinogen content (100 and 29% inhibition). 4. Increases in acid phosphatase (ACP) plasma activity, a marker of lysosomal activation, and in lactate dehydrogenase (LDH), a marker of tissue damage, were inhibited by pretreatment with 10 mg kg-1, i.v. of either UR-12633 or WEB-2086 (100% and 69% inhibition, ACP; 62 and 48% inhibition, LDH). Hyperglycaemia (71 and 46%) and hyperlactacidaemia (92 and 56%) were also inhibited. 5. UR-12633, but not WEB-2086, inhibited the LPS-induced increase in vascular permeability in rats, as shown by prevention of haemoconcentration and, to a lesser degree, the increase in Evans blue dye extravasation. 6. In a series of nine reference compounds and UR-12633, we found a high correlation (P < 0.001) between PAF antagonist activity, measured as the inhibition of PAF-induced rabbit platelet aggregation or PAF-induced mortality in mice and the inhibition of LPS-induced mortality. 7. In spite of the multifactorial nature of endotoxic shock, in which many mediators may be involved, the new potent PAF antagonist, UR-12633, proved effective in protecting against changes in most shock markers. These data strongly suggest a key role for PAF in the pathogenesis of endotoxic shock in rodents.
Collapse
Affiliation(s)
- M Giral
- Research Center, J. Uriach & Cía, Barcelona, Spain
| | | | | | | | | | | |
Collapse
|
14
|
Silva CL, Cruz HN, Violante FA, Cordeiro RS, Martins MA, Noël F. Formation of a highly stable complex between BN 50730 [tetrahydro-4,7,8,10 methyl-1(chloro-2 phenyl)-6 (methoxy-4 phenyl-carbamoyl)-9 pyrido [4',3'-4,5] thieno [3,2-f] triazolo-1,2,4 [4,3-a] diazepine-1,4] and the platelet-activating factor receptor in rabbit platelet membranes. Biochem Pharmacol 1996; 51:193-6. [PMID: 8615889 DOI: 10.1016/0006-2952(95)02158-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BN 50730 [tetrahydro-4,7,8,10 methyl-1(chloro-2 phenyl)-6 (methoxy-4 phenyl-carbamoyl)-9 pyrido [4',3'-4,5] thieno [3,2-f] triazolo-1,2,4 [4,3-alpha] diazepine-1,4], a novel platelet-activating factor (PAF) receptor antagonist with a hetrazepine structure, decreased the maximal number of binding sites (Bmax) of [3H]PAF in rabbit platelet membranes without altering its dissociation constant. Platelet aggregation induced by 1 microM PAF was prevented by preincubation with 1 microM BN 50730. The washing of the platelets preincubated with BN 50730 failed to revert its inhibitory effects. We conclude that BN 50730 acts as a non-competitive antagonist of the PAF receptor, due to the formation of a highly stable drug-receptor complex.
Collapse
Affiliation(s)
- C L Silva
- Departamento de Farmacologia Basica e Clínica, Universidade Federal do Rio de Janeiro, Brazil
| | | | | | | | | | | |
Collapse
|
15
|
Prehn JH, Krieglstein J. Platelet-activating factor antagonists reduce excitotoxic damage in cultured neurons from embryonic chick telencephalon and protect the rat hippocampus and neocortex from ischemic injury in vivo. J Neurosci Res 1993; 34:179-88. [PMID: 8095559 DOI: 10.1002/jnr.490340205] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The neuroprotective effects of the platelet-activating factor (PAF) antagonists BN 52020 and BN 52021 were determined in a temperature-controlled model of transient forebrain ischemia in the rat (occlusion of both common carotid arteries combined with lowering of the mean arterial blood pressure to 40 mm Hg for 10 min). After 7 days of recirculation, the ischemic neuronal damage was evaluated histologically within the hippocampus and neocortex. Combined pre- and post-treatment with the PAF antagonists (2 x 25 mg/kg, s.c.) significantly reduced the resulting neuronal damage of the CA1 and CA3 hippocampal subfields and of the occipital and parietal cerebral cortex. The two PAF antagonists were also tested for their neuroprotective activity in primary neuronal cultures isolated from embryonic chick telencephalon. Since an excessive activation of excitatory amino acid receptors is discussed to be of importance for the ischemic brain damage, the cultured neurons were exposed to the excitatory amino acid L-glutamate (1 mM) for a period of 60 min. Twenty hours after the excitotoxic insult, BN 52020- and BN 52021-treated cultures (1-100 microM) showed both a better preserved morphology, as well as a dose-dependent increase in cell viability and protein content compared to the control cultures. Our results demonstrate that the PAF antagonists BN 52020 and BN 52021 have the capacity to protect brain tissue against ischemic neuronal damage independent of hypothermic effects and are also capable of reducing excitotoxic damage of telencephalic neurons from chick embryos cultured in the absence of glial or endothelial cells. We thus propose that PAF plays an important role in the pathophysiology of ischemic/excitotoxic neuronal injury via a direct action on neurons.
Collapse
Affiliation(s)
- J H Prehn
- Institut für Pharmakologie und Toxikologie, Philipps-Universität, Marburg, Germany
| | | |
Collapse
|