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Abecunas C, Fallahi-Sichani M. Multivariate modeling of metabolic state vulnerabilities across diverse cancer contexts reveals synthetically lethal associations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.28.569098. [PMID: 38076921 PMCID: PMC10705426 DOI: 10.1101/2023.11.28.569098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Targeting the distinct metabolic needs of tumor cells has recently emerged as a promising strategy for cancer therapy. The heterogeneous, context-dependent nature of cancer cell metabolism, however, poses challenges in identifying effective therapeutic interventions. Here, we utilize various unsupervised and supervised multivariate modeling approaches to systematically pinpoint recurrent metabolic states within hundreds of cancer cell lines, elucidate their association with tissue lineage and growth environments, and uncover vulnerabilities linked to their metabolic states across diverse genetic and tissue contexts. We validate key findings using data from an independent set of cell lines, pharmacological screens, and via single-cell analysis of patient-derived tumors. Our analysis uncovers new synthetically lethal associations between the tumor metabolic state (e.g., oxidative phosphorylation), driver mutations (e.g., loss of tumor suppressor PTEN), and actionable biological targets (e.g., mitochondrial electron transport chain). Investigating these relationships could inform the development of more precise and context-specific, metabolism-targeted cancer therapies.
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Affiliation(s)
- Cara Abecunas
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109
- Present address: Vindhya Data Science, 20 Bayless Ridge Court, Morrisville, NC 27560
| | - Mohammad Fallahi-Sichani
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908
- UVA Comprehensive Cancer Center, University of Virginia, Charlottesville, VA 22908
- Lead contact
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Antibacterial, Antibiofilm, and Antioxidant Activity of 15 Different Plant-Based Natural Compounds in Comparison with Ciprofloxacin and Gentamicin. Antibiotics (Basel) 2022; 11:antibiotics11081099. [PMID: 36009966 PMCID: PMC9404727 DOI: 10.3390/antibiotics11081099] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/04/2022] [Accepted: 08/10/2022] [Indexed: 11/17/2022] Open
Abstract
Plant-based natural compounds (PBCs) are comparatively explored in this study to identify the most effective and safe antibacterial agent/s against six World Health Organization concern pathogens. Based on a contained systematic review, 11 of the most potent PBCs as antibacterial agents are included in this study. The antibacterial and antibiofilm efficacy of the included PBCs are compared with each other as well as common antibiotics (ciprofloxacin and gentamicin). The whole plants of two different strains of Cannabis sativa are extracted to compare the results with sourced ultrapure components. Out of 15 PBCs, tetrahydrocannabinol, cannabidiol, cinnamaldehyde, and carvacrol show promising antibacterial and antibiofilm efficacy. The most common antibacterial mechanisms are explored, and all of our selected PBCs utilize the same pathway for their antibacterial effects. They mostly target the bacterial cell membrane in the initial step rather than the other mechanisms. Reactive oxygen species production and targeting [Fe-S] centres in the respiratory enzymes are not found to be significant, which could be part of the explanation as to why they are not toxic to eukaryotic cells. Toxicity and antioxidant tests show that they are not only nontoxic but also have antioxidant properties in Caenorhabditis elegans as an animal model.
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Zharova TV, Kozlovsky VS, Grivennikova VG. Interaction of Venturicidin and F o·F 1-ATPase/ATP Synthase of Tightly Coupled Subbacterial Particles of Paracoccus denitrificans in Energized Membranes. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:742-751. [PMID: 36171655 DOI: 10.1134/s0006297922080065] [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: 04/15/2022] [Revised: 05/18/2022] [Accepted: 05/20/2022] [Indexed: 06/16/2023]
Abstract
Proton-translocating Fo×F1-ATPase/synthase that catalyzes synthesis and hydrolysis of ATP is commonly considered to be a reversibly functioning complex. We have previously shown that venturicidin, a specific Fo-directed inhibitor, blocks the synthesis and hydrolysis of ATP with a significant difference in the affinity [Zharova, T. V. and Vinogradov, A. D. (2017) Biochim. Biophys. Acta, 1858, 939-944]. In this paper, we have studied in detail inhibition of Fo×F1-ATPase/synthase by venturicidin in tightly coupled membranes of Paracoccus denitrificans under conditions of membrane potential generation. ATP hydrolysis was followed by the ATP-dependent succinate-supported NAD+ reduction (potential-dependent reverse electron transfer) catalyzed by the respiratory chain complex I. It has been demonstrated that membrane energization did not affect the affinity of Fo×F1-ATPase/synthase for venturicidin. The dependence of the residual ATP synthase activity on the concentration of venturicidin approximated a linear function, whereas the dependence of ATP hydrolysis was sigmoidal: at low inhibitor concentrations venturicidin strongly inhibited ATP synthesis without decrease in the rate of ATP hydrolysis. A model is proposed suggesting that ATP synthesis and ATP hydrolysis are catalyzed by two different forms of Fo×F1.
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Affiliation(s)
- Tatyana V Zharova
- Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
| | - Vladimir S Kozlovsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Vera G Grivennikova
- Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
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4
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Abstract
ATP synthase is an essential enzyme found in all known forms of life, generating the majority of cellular energy via a rotary catalytic mechanism. Here, we describe the in-depth methods for expression, purification, and functional assessment of E. coli ATP synthase.
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5
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Brückner H, Degenkolb T. Sequences of Tolypins, Insecticidal Efrapeptin-Type Peptaibiotics from Species of the Fungal Genus Tolypocladium. Chem Biodivers 2020; 17:e2000276. [PMID: 32573986 DOI: 10.1002/cbdv.202000276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 05/12/2020] [Indexed: 11/09/2022]
Abstract
A peptide mixture named tolypin, originally isolated from species of the fungal genus Tolypocladium, was structurally characterised and sequences compared to those reported for efrapeptins isolated from strains of Tolypocladium inflatum. Chiral amino acid analysis, direct infusion, and online HPLC electrospray ionization tandem mass spectrometry provided composition, molecular weights of peptides, and series of diagnostic fragment ions. Sequences deduced from ESI-MS revealed that tolypins C-G are identical to efrapeptins C-G. The results were corroborated by ESI-MS and HPLC of an authentic efrapeptin sample from Eli Lilly Research Laboratories (USA). Comparison of the HPLC elution profiles of efrapeptin and tolypin indicated a pronounced microheterogeneity of the former. A high-resolution HPLC of authentic efrapeptin has not been published before. Close relationship and partial identity of sequences of tolypins and efrapeptins, which had previously been postulated, were definitely proven. The geographical origin of the two most important T. inflatum strains used for sequencing of efrapeptins/tolypins could unambiguously be clarified. A new minor compound, designated tolypin H1, was sequenced. High proportions of helicogenic Aib (α-aminoisobutyric acid) and l-isovaline, N-terminal acetyl-l-pipecolic acid and the unusual, amide-bound C-terminal residue, named (S)-2-amino-1-(1,5-diazabicyclo[4.3.0]non-5-ene-5-ylium)-4-methylpentane corresponding to 1-[(2S)-2-amino-4-methylpentyl]-2,3,4,6,7,8-hexahydropyrrolo[1,2-a]pyrimidin-1-ium, define these peptides as linear, cationic peptaibiotics.
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Affiliation(s)
- Hans Brückner
- Interdisciplinary Research Centre for BioSystems, Land Use and Nutrition (IFZ), Department of Food Sciences, Institute of Nutritional Science, Justus-Liebig University of Giessen, Heinrich-Buff-Ring 26-32, DE, 35392 Giessen, Germany
| | - Thomas Degenkolb
- Interdisciplinary Research Centre for BioSystems, Land Use and Nutrition (IFZ), Department of Food Sciences, Institute of Nutritional Science, Justus-Liebig University of Giessen, Heinrich-Buff-Ring 26-32, DE, 35392 Giessen, Germany.,Present address: Interdisciplinary Research Centre for BioSystems, Land Use and Nutrition (IFZ), Institute of Insect Biotechnology, Department of Applied Entomology, Justus-Liebig University of Giessen, Heinrich-Buff-Ring 26-32, DE, 35392 Giessen, Germany
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6
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Scapin G, Goulard MC, Dharampuriya PR, Cillis JL, Shah DI. Analysis of Hematopoietic Stem Progenitor Cell Metabolism. J Vis Exp 2019. [PMID: 31762453 DOI: 10.3791/60234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Hematopoietic stem progenitor cells (HSPCs) have distinct metabolic plasticity, which allows them to transition from their quiescent state to a differentiation state to sustain demands of the blood formation. However, it has been difficult to analyze the metabolic status (mitochondrial respiration and glycolysis) of HSPCs due to their limited numbers and lack of optimized protocols for non-adherent, fragile HSPCs. Here, we provide a set of clear, step-by-step instructions to measure metabolic respiration (oxygen consumption rate; OCR) and glycolysis (extracellular acidification rate; ECAR) of murine bone marrow-LineagenegSca1+c-Kit+ (LSK) HSPCs. This protocol provides a higher amount of LSK HSPCs from murine bone marrow, improves the viability of HSPCs during incubation, facilitates extracellular flux analyses of non-adherent HSPCs, and provides optimized injection protocols (concentration and time) for drugs targeting oxidative phosphorylation and glycolytic pathways. This method enables the prediction of the metabolic status and the health of HSPCs during blood development and diseases.
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Affiliation(s)
- Giorgia Scapin
- Nationwide Children's Hospital; The Ohio State University College of Medicine; The Ohio State University Comprehensive Cancer Center
| | - Marie C Goulard
- Nationwide Children's Hospital; The Ohio State University College of Medicine; The Ohio State University Comprehensive Cancer Center
| | - Priyanka R Dharampuriya
- Nationwide Children's Hospital; The Ohio State University College of Medicine; The Ohio State University Comprehensive Cancer Center
| | - Jennifer L Cillis
- Nationwide Children's Hospital; The Ohio State University College of Medicine; The Ohio State University Comprehensive Cancer Center
| | - Dhvanit I Shah
- Nationwide Children's Hospital; The Ohio State University College of Medicine; The Ohio State University Comprehensive Cancer Center;
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Narang R, Kumar R, Kalra S, Nayak SK, Khatik GL, Kumar GN, Sudhakar K, Singh SK. Recent advancements in mechanistic studies and structure activity relationship of FoF1 ATP synthase inhibitor as antimicrobial agent. Eur J Med Chem 2019; 182:111644. [DOI: 10.1016/j.ejmech.2019.111644] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 08/22/2019] [Accepted: 08/23/2019] [Indexed: 12/17/2022]
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8
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Forouzesh A, Samadi Foroushani S, Forouzesh F, Zand E. Reliable Target Prediction of Bioactive Molecules Based on Chemical Similarity Without Employing Statistical Methods. Front Pharmacol 2019; 10:835. [PMID: 31404334 PMCID: PMC6676798 DOI: 10.3389/fphar.2019.00835] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 07/01/2019] [Indexed: 12/11/2022] Open
Abstract
The prediction of biological targets of bioactive molecules from machine-readable materials can be routinely performed by computational target prediction tools (CTPTs). However, the prediction of biological targets of bioactive molecules from non-digital materials (e.g., printed or handwritten documents) has not been possible due to the complex nature of bioactive molecules and impossibility of employing computations. Improving the target prediction accuracy is the most important challenge for computational target prediction. A minimum structure is identified for each group of neighbor molecules in the proposed method. Each group of neighbor molecules represents a distinct structural class of molecules with the same function in relation to the target. The minimum structure is employed as a query to search for molecules that perfectly satisfy the minimum structure of what is guessed crucial for the targeted activity. The proposed method is based on chemical similarity, but only molecules that perfectly satisfy the minimum structure are considered. Structurally related bioactive molecules found with the same minimum structure were considered as neighbor molecules of the query molecule. The known target of the neighbor molecule is used as a reference for predicting the target of the neighbor molecule with an unknown target. A lot of information is needed to identify the minimum structure, because it is necessary to know which part(s) of the bioactive molecule determines the precise target or targets responsible for the observed phenotype. Therefore, the predicted target based on the minimum structure without employing the statistical significance is considered as a reliable prediction. Since only molecules that perfectly (and not partly) satisfy the minimum structure are considered, the minimum structure can be used without similarity calculations in non-digital materials and with similarity calculations (perfect similarity) in machine-readable materials. Nine tools (PASS online, PPB, SEA, TargetHunter, PharmMapper, ChemProt, HitPick, SuperPred, and SPiDER), which can be used for computational target prediction, are compared with the proposed method for 550 target predictions. The proposed method, SEA, PPB, and PASS online, showed the best quality and quantity for the accurate predictions.
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Affiliation(s)
- Abed Forouzesh
- Iranian Research Institute of Plant Protection, Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran
| | - Sadegh Samadi Foroushani
- Iranian Research Institute of Plant Protection, Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran
| | - Fatemeh Forouzesh
- Department of Medicine, Tehran Medical Branch, Islamic Azad University, Tehran, Iran
| | - Eskandar Zand
- Iranian Research Institute of Plant Protection, Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran
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Dutta Gupta S, Bommaka MK, Banerjee A. Inhibiting protein-protein interactions of Hsp90 as a novel approach for targeting cancer. Eur J Med Chem 2019; 178:48-63. [PMID: 31176095 DOI: 10.1016/j.ejmech.2019.05.073] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 05/17/2019] [Accepted: 05/27/2019] [Indexed: 12/26/2022]
Abstract
The ninety kilo Dalton molecular weight heat shock protein (Hsp90) is an attractive target for the discovery of novel anticancer agents. Several strategies have been employed for the development of inhibitors against this polypeptide. The most successful strategy is targeting the N-terminal ATP binding region of the chaperone. However, till date not a single molecule reached Phase-IV of clinical trials from this class of Hsp90 inhibitors. The other approach is to target the Cterminal region of the protein. The success with this approach has been limited due to lack of well-defined ligand binding pocket in this terminal. The other promising strategy is to prevent the interaction of client proteins/co-chaperones with Hsp90 protein, i.e., protein-protein interaction inhibitors of Hsp90. The review focuses on advantage of this approach along with the recent advances in the discovery of inhibitors by following this strategy. Additionally, the biology of the client protein/co-chaperone binding site of Hsp90 is also discussed.
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Affiliation(s)
- Sayan Dutta Gupta
- Department of Pharmaceutical Chemistry, Gokaraju Rangaraju College of Pharmacy, Osmania University, Hyderabad, India.
| | - Manish Kumar Bommaka
- Department of Pharmaceutical Chemistry, Gokaraju Rangaraju College of Pharmacy, Osmania University, Hyderabad, India; School of Chemistry, University of Hyderabad, Hyderabad, India
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10
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Zahreddine HA, Culjkovic-Kraljacic B, Gasiorek J, Duchaine J, Borden KLB. GLI1-Inducible Glucuronidation Targets a Broad Spectrum of Drugs. ACS Chem Biol 2019; 14:348-355. [PMID: 30763062 DOI: 10.1021/acschembio.8b01118] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cancer therapies are plagued by resistance. Previously, we discovered a novel form of cancer drug resistance where the Glioma-associated protein 1 (GLI1) elevates UGT1A glucuronidation enzymes, thereby glucuronidating cytarabine and ribavirin, leading to resistance in leukemia patients. Here, we demonstrate that GLI1 imparts resistance to ∼40 compounds, including FDA-approved drugs with disparate chemotypes ( e.g., methotrexate and venetoclax). GLI1 indirectly elevates UGT1As via the chaperone calreticulin, which is required for resistance. Further, we demonstrate that resistant cells are more sensitive to ATP inhibitors, suggesting an Achilles' heel, which could be exploited in the future. In all, we identify GLI1-inducible glucuronidation as a broad-spectrum multidrug resistance pathway.
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Affiliation(s)
- Hiba Ahmad Zahreddine
- Institute for Research in Immunology and Cancer and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Quebec, Canada
| | - Biljana Culjkovic-Kraljacic
- Institute for Research in Immunology and Cancer and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Quebec, Canada
| | - Jadwiga Gasiorek
- Institute for Research in Immunology and Cancer and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Quebec, Canada
| | - Jean Duchaine
- Institute for Research in Immunology and Cancer and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Quebec, Canada
| | - Katherine L. B. Borden
- Institute for Research in Immunology and Cancer and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Quebec, Canada
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Ding W, Yousefi K, Shehadeh LA. Isolation, Characterization, And High Throughput Extracellular Flux Analysis of Mouse Primary Renal Tubular Epithelial Cells. J Vis Exp 2018. [PMID: 29985358 PMCID: PMC6101965 DOI: 10.3791/57718] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mitochondrial dysfunction in the renal tubular epithelial cells (TECs) can lead to renal fibrosis, a major cause of chronic kidney disease (CKD). Therefore, assessing mitochondrial function in primary TECs may provide valuable insight into the bioenergetic status of the cells, providing insight into the pathophysiology of CKD. While there are a number of complex protocols available for the isolation and purification of proximal tubules in different species, the field lacks a cost-effective method optimized for tubular cell isolation without the need for purification. Here, we provide an isolation protocol that allows for studies focusing on both primary mouse proximal and distal renal TECs. In addition to cost-effective reagents and minimal animal procedures required in this protocol, the isolated cells maintain high energy levels after isolation and can be sub-cultured up to four passages, allowing for continuous studies. Furthermore, using a high throughput extracellular flux analyzer, we assess the mitochondrial respiration directly in the isolated TECs in a 96-well plate for which we provide recommendations for the optimization of cell density and compound concentration. These observations suggest that this protocol can be used for renal tubular ex vivo studies with a consistent, well-standardized production of renal TECs. This protocol may have broader future applications to study mitochondrial dysfunction associated with renal disorders for drug discovery or drug characterization purposes.
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Affiliation(s)
- Wen Ding
- Department of Molecular and Cellular Pharmacology, University of Miami Leonard M. Miller School of Medicine; Interdisciplinary Stem Cell Institute, University of Miami Leonard M. Miller School of Medicine
| | - Keyvan Yousefi
- Department of Molecular and Cellular Pharmacology, University of Miami Leonard M. Miller School of Medicine; Interdisciplinary Stem Cell Institute, University of Miami Leonard M. Miller School of Medicine
| | - Lina A Shehadeh
- Interdisciplinary Stem Cell Institute, University of Miami Leonard M. Miller School of Medicine; Department of Medicine, Division of Cardiology, University of Miami Leonard M. Miller School of Medicine; Vascular Biology Institute, University of Miami Leonard M. Miller School of Medicine; Peggy and Harold Katz Family Drug Discovery Center, University of Miami Leonard M. Miller School of Medicine;
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12
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Ahmad Z, Hassan SS, Azim S. A Therapeutic Connection between Dietary Phytochemicals and ATP Synthase. Curr Med Chem 2017; 24:3894-3906. [PMID: 28831918 PMCID: PMC5738703 DOI: 10.2174/0929867324666170823125330] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 01/01/1970] [Accepted: 08/18/2017] [Indexed: 12/25/2022]
Abstract
For centuries, phytochemicals have been used to prevent and cure multiple health ailments. Phytochemicals have been reported to have antioxidant, antidiabetic, antitussive, antiparasitic, anticancer, and antimicrobial properties. Generally, the therapeutic use of phy-tochemicals is based on tradition or word of mouth with few evidence-based studies. Moreo-ver, molecular level interactions or molecular targets for the majority of phytochemicals are unknown. In recent years, antibiotic resistance by microbes has become a major healthcare concern. As such, the use of phytochemicals with antimicrobial properties has become perti-nent. Natural compounds from plants, vegetables, herbs, and spices with strong antimicrobial properties present an excellent opportunity for preventing and combating antibiotic resistant microbial infections. ATP synthase is the fundamental means of cellular energy. Inhibition of ATP synthase may deprive cells of required energy leading to cell death, and a variety of die-tary phytochemicals are known to inhibit ATP synthase. Structural modifications of phyto-chemicals have been shown to increase the inhibitory potency and extent of inhibition. Site-directed mutagenic analysis has elucidated the binding site(s) for some phytochemicals on ATP synthase. Amino acid variations in and around the phytochemical binding sites can re-sult in selective binding and inhibition of microbial ATP synthase. In this review, the therapeu-tic connection between dietary phytochemicals and ATP synthase is summarized based on the inhibition of ATP synthase by dietary phytochemicals. Research suggests selective target-ing of ATP synthase is a valuable alternative molecular level approach to combat antibiotic resistant microbial infections.
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Affiliation(s)
- Zulfiqar Ahmad
- Department of Biochemistry, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, Missouri 63501, USA
| | - Sherif S Hassan
- Department of Medical Education, California University of Sciences and Medicine, School of Medicine (Cal Med-SOM), Colton, California 92324, USA
| | - Sofiya Azim
- Department of Biochemistry, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, Missouri 63501, USA
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Zhou T, Li Z, Kang OH, Mun SH, Seo YS, Kong R, Shin DW, Liu XQ, Kwon DY. Antimicrobial activity and synergism of ursolic acid 3-O-α-L-arabinopyranoside with oxacillin against methicillin-resistant Staphylococcus aureus. Int J Mol Med 2017; 40:1285-1293. [PMID: 28848992 DOI: 10.3892/ijmm.2017.3099] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 07/28/2017] [Indexed: 11/06/2022] Open
Abstract
The objective of the present study was to investigate the antibacterial activity of a single constituent, ursolic acid 3-O-α-L-arabinopyranoside (URS), isolated from the leaves of Acanthopanax henryi (Oliv.) Harms, alone and in combination with oxacillin (OXA) against methicillin-resistant Staphylococcus aureus (MRSA). A broth microdilution assay was used to determine the minimal inhibitory concentration (MIC). The synergistic effects of URS and OXA were determined using a checkerboard dilution test and time-kill curve assay. The mechanism of action of URS against MRSA was analyzed using a viability assay in the presence of a detergent and an ATPase inhibitor. Morphological changes in the URS-treated MRSA strains were evaluated via transmission electron microscopy (TEM). In addition, the producing penicillin-binding protein 2a (PBP2a) protein level was analyzed using western blotting. The MIC value of URS against MRSA was found to be 6.25 µg/ml and there was a partial synergistic effect between OXA and URS. The time-kill growth curves were suppressed by OXA combined with URS at a sub-inhibitory level. Compared to the optical density at 600 nm (OD600) value of URS alone (0.09 µg/ml), the OD600 values of the suspension in the presence of 0.09 µg/ml URS and 0.00001% Triton X-100 or 250 µg/ml N,N'-dicyclohexylcarbodiimide reduced by 56.6 and 85.9%, respectively. The TEM images of MRSA indicated damage to the cell wall, broken cell membranes and cell lysis following treatment with URS and OXA. Finally, an inhibitory effect on the expression of PBP2a protein was observed when cells were treated with URS and OXA compared with untreated controls. The present study suggested that URS was significantly active against MRSA infections and revealed the potential of URS as an effective natural antibiotic.
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Affiliation(s)
- Tian Zhou
- Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Zhi Li
- School of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan 410-208, P.R. China
| | - Ok-Hwa Kang
- Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Su-Hyun Mun
- Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Yun-Soo Seo
- Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Ryong Kong
- Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Dong-Won Shin
- Department of Oriental Medicine Resources, College of Bio Industry Science, Sunchon National University, Sunchon, Jeonnam 540-742, Republic of Korea
| | - Xiang-Qian Liu
- School of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan 410-208, P.R. China
| | - Dong-Yeul Kwon
- Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
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Zharova TV, Vinogradov AD. Functional heterogeneity of F o·F 1H +-ATPase/synthase in coupled Paracoccus denitrificans plasma membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:939-944. [PMID: 28803911 DOI: 10.1016/j.bbabio.2017.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/10/2017] [Accepted: 08/09/2017] [Indexed: 11/16/2022]
Abstract
Fo·F1H+-ATPase/synthase in coupled plasma membrane vesicles of Paracoccus denitrificans catalyzes ATP hydrolysis and/or ATP synthesis with comparable enzyme turnover. Significant difference in pH-profile of these alternative activities is seen: decreasing pH from 8.0 to 7.0 results in reversible inhibition of hydrolytic activity, whereas ATP synthesis activity is not changed. The inhibition of ATPase activity upon acidification results from neither change in ADP(Mg2+)-induced deactivation nor the energy-dependent enzyme activation. Vmax, not apparent KmATP is affected by lowering the pH. Venturicidin noncompetitively inhibits ATP synthesis and coupled ATP hydrolysis, showing significant difference in the affinity to its inhibitory site depending on the direction of the catalysis. This difference cannot be attributed to variations of the substrate-enzyme intermediates for steady-state forward and back reactions or to possible equilibrium between ATP hydrolase and ATP synthase Fo·F1 modes of the opposite directions of catalysis. The data are interpreted as to suggest that distinct non-equilibrated molecular isoforms of Fo·F1 ATP synthase and ATP hydrolase exist in coupled energy-transducing membranes.
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Affiliation(s)
- Tatyana V Zharova
- Department of Biochemistry, School of Biology, Moscow State University, Moscow 119234, Russian Federation
| | - Andrei D Vinogradov
- Department of Biochemistry, School of Biology, Moscow State University, Moscow 119234, Russian Federation.
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15
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Traba J, Miozzo P, Akkaya B, Pierce SK, Akkaya M. An Optimized Protocol to Analyze Glycolysis and Mitochondrial Respiration in Lymphocytes. J Vis Exp 2016. [PMID: 27911401 PMCID: PMC5226256 DOI: 10.3791/54918] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Lymphocytes respond to a variety of stimuli by activating intracellular signaling pathways, which in turn leads to rapid cellular proliferation, migration and differentiation, and cytokine production. All of these events are tightly linked to the energy status of the cell, and therefore studying the energy-producing pathways may give clues about the overall functionality of these cells. The extracellular flux analyzer is a commonly used device for evaluating the performance of glycolysis and mitochondrial respiration in many cell types. This system has been used to study immune cells in a few published reports, yet a comprehensive protocol optimized particularly for lymphocytes is lacking. Lymphocytes are fragile cells that survive poorly in ex vivo conditions. Oftentimes lymphocyte subsets are rare, and working with low cell numbers is inevitable. Thus, an experimental strategy that addresses these difficulties is required. Here, we provide a protocol that allows for rapid isolation of viable lymphocytes from lymphoid tissues, and for the analysis of their metabolic states in the extracellular flux analyzer. Furthermore, we provide results of experiments in which the metabolic activities of several lymphocyte subtypes at different cell densities were compared. These observations suggest that our protocol can be used to achieve consistent, well-standardized results even at low cell concentrations, and thus it may have broad applications in future studies focusing on the characterization of metabolic events in immune cells.
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Affiliation(s)
- Javier Traba
- Laboratory of Mitochondrial Biology and Metabolism, National Heart, Lung, and Blood Institute, National Institutes of Health
| | - Pietro Miozzo
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health
| | - Billur Akkaya
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health
| | - Susan K Pierce
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health
| | - Munir Akkaya
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health;
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16
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Joung DK, Mun SH, Choi SH, Kang OH, Kim SB, Lee YS, Zhou T, Kong R, Choi JG, Shin DW, Kim YC, Lee DS, Kwon DY. Antibacterial activity of oxyresveratrol against methicillin-resistant Staphylococcus aureus and its mechanism. Exp Ther Med 2016; 12:1579-1584. [PMID: 27588079 DOI: 10.3892/etm.2016.3486] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 10/22/2015] [Indexed: 11/06/2022] Open
Abstract
Oxyresveratrol (ORV) is a naturally occurring compound found in mulberries that exhibits a wide spectrum of biological activities. However, the underlying mechanism of the action of ORV against the methicillin-resistant S. aureus (MRSA) pathogen has not yet been reported. MRSA is multidrug-resistant, causing skin and other types of infections. The aim of the present study was to examine the antimicrobial activity of ORV and the underlying mechanism of its action on MRSA. The antibacterial activity of ORV was evaluated using a minimum inhibitory concentration (MIC) assay, and the mechanism of its antibacterial action on S. aureus was investigated using a combination of ORV with detergent, ATPase inhibitors and peptidoglycan (PGN). In addition, the survival characteristics and changes in MRSA morphology were monitored using transmission electron microscopy (TEM). The MIC value of ORV against all S. aureus strains was found to be 125 µg/ml. The optical density at 600 nm of each suspension treated using a combination of ORV with Triton X-100, N,N'-dicyclohexylcarbodiimide or sodium azide was reduced by 68.9-89.8% compared with the value upon treatment with ORV alone. In the ORV and PGN combination assay, direct binding of ORV with PGN from S. aureus was evident. Furthermore, TEM examination of MRSA treated with ORV showed alterations in septa formation. In conclusion, these results showed that ORV has a strong antibacterial effect against S. aureus, mainly by increasing membrane permeability and inhibiting ATPase when combined with other drugs.
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Affiliation(s)
- Dae-Ki Joung
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Su-Hyun Mun
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Sung-Hoon Choi
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Ok-Hwa Kang
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Sung-Bae Kim
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Young-Seob Lee
- Department of Herbal Crop Research, National Institute of Horticultural and Herbal Science, Rural Development Administration, Eumsung, Chungbuk 369-873, Republic of Korea
| | - Tian Zhou
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Ryong Kong
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Jang-Gi Choi
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Dong-Won Shin
- Department of Oriental Medicine Resources, Sunchon National University, Suncheon, Jeonnam 540-742, Republic of Korea
| | - Youn-Chul Kim
- Standardized Material Bank for New Botanical Drugs, College of Pharmacy, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Dong-Sung Lee
- Standardized Material Bank for New Botanical Drugs, College of Pharmacy, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
| | - Dong-Yeul Kwon
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
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17
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A Dual-Ligand Liposomal System Composed of a Cell-Penetrating Peptide and a Mitochondrial RNA Aptamer Synergistically Facilitates Cellular Uptake and Mitochondrial Targeting. J Pharm Sci 2016; 105:1705-1713. [PMID: 27056631 DOI: 10.1016/j.xphs.2016.03.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 02/08/2016] [Accepted: 03/01/2016] [Indexed: 01/22/2023]
Abstract
It has been reported that the use of mitochondrial RNA aptamers including RNase P (RP) results in the selective mitochondrial delivery of endogenous and exogenous RNAs. The issue of whether these aptamers would be useful ligands for the mitochondrial targeting of a nanoparticle has not been demonstrated to date because nanocarriers modified with these RNA aptamers are insufficiently internalized by cells. We report here on the development of a dual-ligand liposomal system composed of octaarginine (R8), a device that enhances cellular uptake, and an RP aptamer for mitochondrial targeting to permit a nanocarrier to be efficiently delivered to mitochondria. Surprisingly, the cellular uptake of the R8-modified nanocarrier was facilitated by modification with an RP aptamer. The optimal composition of a nanocarrier needed for efficient cellular uptake and mitochondrial targeting was determined. In a confocal laser scanning microscopy analysis, the dual-ligand-modified nanocarrier was found to result in effective mitochondrial targeting through an ATP-dependent pathway and was much more effective than a single-ligand R8-modified nanocarrier. This is the first report of the regulation of intracellular trafficking by a mitochondrial RNA aptamer-modified nanocarrier system.
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18
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Calzia D, Oneto M, Caicci F, Bianchini P, Ravera S, Bartolucci M, Diaspro A, Degan P, Manni L, Traverso CE, Panfoli I. Effect of polyphenolic phytochemicals on ectopic oxidative phosphorylation in rod outer segments of bovine retina. Br J Pharmacol 2015; 172:3890-903. [PMID: 25917043 DOI: 10.1111/bph.13173] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 03/24/2015] [Accepted: 04/20/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE The rod outer segments (OS) of the retina are specialized organelles where phototransduction takes place. The mitochondrial electron transport complexes I-IV, cytochrome c and Fo F1 -ATP synthase are functionally expressed in the OS disks. Here, we have studied the effect of some polyphenolic compounds acting as inhibitors of mitochondrial ATPase/synthase activity on the OS ectopic Fo F1 - ATP synthase. The mechanism of apoptosis in the OS was also investigated studying the expression of cytochrome c, caspase 9 and 3 and Apaf-1. EXPERIMENTAL APPROACH We prepared OS from fresh bovine retinae. Semi-quantitative Western blotting, confocal and electron microscopy, and cytofluorimetry were used along with biochemical analyses such as oximetry, ATP synthesis and hydrolysis. KEY RESULTS Resveratrol and curcumin plus piperine inhibited ATP synthesis and oxygen consumption in the OS. Epigallocatechin gallate and quercetin inhibited ATP hydrolysis and oxygen consumption in the OS. Malondialdehyde and hydrogen peroxide were produced in respiring OS in the presence of substrates. Cytochrome c was located inside the disk membranes. Procaspase 9 and 3, as well as Apaf-1 were expressed in the OS. CONCLUSIONS AND IMPLICATIONS These polyphenolic phytochemicals modulated the Fo F1 -ATP synthase activity of the the OS reducing production of reactive oxygen intermediates by the OS ectopic electron transport chain. Polyphenols decrease membrane peroxidation and cytochrome c release from disks, preventing the induction of caspase-dependent apoptosis in the OS Such effects are relevant in the design of protection against functional impairment of the OS following oxidative stress from exposure to intense illumination.
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Affiliation(s)
- Daniela Calzia
- Department of Pharmacy-DIFAR, Biochemistry and Physiology Laboratory, University of Genoa, Genova, Italy
| | - Michele Oneto
- Department of Pharmacy-DIFAR, Biochemistry and Physiology Laboratory, University of Genoa, Genova, Italy
| | | | - Paolo Bianchini
- Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy
| | - Silvia Ravera
- Department of Pharmacy-DIFAR, Biochemistry and Physiology Laboratory, University of Genoa, Genova, Italy
| | - Martina Bartolucci
- Department of Pharmacy-DIFAR, Biochemistry and Physiology Laboratory, University of Genoa, Genova, Italy
| | - Alberto Diaspro
- Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy
| | - Paolo Degan
- UOC Mutagenesi, IRCCS Azienda Ospedaliera Universitaria San Martino - Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy
| | - Lucia Manni
- Department of Biology, Università di Padova, Padova, Italy
| | - Carlo Enrico Traverso
- Clinica Oculistica, Di.N.O.G.M.I., University of Genoa, IRCCS Azienda Ospedaliera Universitaria San Martino - Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy
| | - Isabella Panfoli
- Department of Pharmacy-DIFAR, Biochemistry and Physiology Laboratory, University of Genoa, Genova, Italy
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19
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Lee HI, Lee SK, Kwon YM, Song YS. Antibacterial Effect of Haedokgeumhwa-san against Methicillin-Resistant Staphylococcus aureus. ACTA ACUST UNITED AC 2015. [DOI: 10.18325/jkmr.2015.25.2.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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20
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Mun SH, Kim SB, Kong R, Choi JG, Kim YC, Shin DW, Kang OH, Kwon DY. Curcumin reverse methicillin resistance in Staphylococcus aureus. Molecules 2014; 19:18283-95. [PMID: 25389660 PMCID: PMC6271166 DOI: 10.3390/molecules191118283] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 09/25/2014] [Accepted: 10/11/2014] [Indexed: 11/24/2022] Open
Abstract
Curcumin, a natural polyphenolic flavonoid extracted from the rhizome of Curcuma longa L., was shown to possess superior potency to resensitize methicillin-resistant Staphylococcus aureus (MRSA) to antibiotics. Previous studies have shown the synergistic activity of curcumin with β-lactam and quinolone antibiotics. Further, to understand the anti-MRSA mechanism of curcumin, we investigated the potentiated effect of curcumin by its interaction in diverse conditions. The mechanism of anti-MRSA action of curcumin was analyzed by the viability assay in the presence of detergents, ATPase inhibitors and peptidoglycan (PGN) from S. aureus, and the PBP2a protein level was analyzed by western blotting. The morphological changes in the curcumin-treated MRSA strains were investigated by transmission electron microscopy (TEM). We analyzed increased susceptibility to MRSA isolates in the presence of curcumin. The optical densities at 600 nm (OD600) of the suspensions treated with the combinations of curcumin with triton X-100 and Tris were reduced to 63% and 59%, respectively, compared to curcumin without treatment. N,N'-dicyclohexylcarbodiimide (DCCD) and sodium azide (NaN3) were reduced to 94% and 55%, respectively. When peptidoglycan (PGN) from S. aureus was combined with curcumin, PGN (0–125 μg/mL) gradually blocked the antibacterial activity of curcumin (125 μg/mL); however, at a concentration of 125 µg/mL PGN, it did not completely block curcumin. Curcumin has a significant effect on the protein level of PBP2a. The TEM images of MRSA showed damage of the cell wall, disruption of the cytoplasmic contents, broken cell membrane and cell lysis after the treatment of curcumin. These data indicate a remarkable antibacterial effect of curcumin, with membrane permeability enhancers and ATPase inhibitors, and curcumin did not directly bind to PGN on the cell wall. Further, the antimicrobial action of curcumin involved in the PBP2a-mediated resistance mechanism was investigated.
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Affiliation(s)
- Su-Hyun Mun
- BK21 Plus Team, Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, Korea
| | - Sung-Bae Kim
- BK21 Plus Team, Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, Korea
| | - Ryong Kong
- BK21 Plus Team, Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, Korea
| | - Jang-Gi Choi
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Korea
| | - Youn-Chul Kim
- Standardized Material Bank for New Botanical Drugs, College of Pharmacy, Wonkwang University, Iksan, Jeonbuk 570-749, Korea
| | - Dong-Won Shin
- Department of Oriental Medicine Resources, College of Bio Industry Science, Sunchon National University, Sunchon, Jeonnam 540-742, Korea
| | - Ok-Hwa Kang
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Korea
| | - Dong-Yeul Kwon
- BK21 Plus Team, Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, Korea.
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21
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Mun SH, Joung DK, Kim SB, Park SJ, Seo YS, Gong R, Choi JG, Shin DW, Rho JR, Kang OH, Kwon DY. The mechanism of antimicrobial activity of sophoraflavanone B against methicillin-resistant Staphylococcus aureus. Foodborne Pathog Dis 2014; 11:234-9. [PMID: 24601672 DOI: 10.1089/fpd.2013.1627] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sophoraflavanone B (SPF-B), a prenylated flavonoid, can be isolated from the roots of Desmodium caudatum. The aim of this study was to determine the mechanism of SPF-B's antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA). MRSA is a multidrug-resistant pathogen and the main cause of hospital- and community-acquired infections. The minimum inhibitory concentration (MIC) of SPF-B was assessed using the broth microdilution method. The mechanism of action of SPF-B on S. aureus was analyzed in combination assays incorporating detergents, ATPase inhibitors, and peptidoglycan (PGN) derived from S. aureus. Furthermore, morphological changes in the SPF-B-treated MRSA strains were investigated using transmission electron microscopy. The MIC of SPF-B for MRSA was in the range of 15.6-31.25 μg/mL. The mechanism of action of SPF-B on MRSA was investigated using combination assays with detergent and ATPase inhibitors. The optical density at 600 nm of MRSA suspensions treated with a combination of detergent and SPF-B reduced the MRSA by 63%-73%. In the SPF-B and PGN combination assay, direct binding of SPF-B with PGN from S. aureus was evident. These data may be validated for the development of new antibacterial drugs for low MRSA resistance.
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Affiliation(s)
- Su-Hyun Mun
- 1 BK21 Plus Team, Professional Graduate School of Oriental Medicine, Wonkwang University , Iksan, Jeonbuk, Korea
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22
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Bonifaz LC, Cervantes-Silva MP, Ontiveros-Dotor E, López-Villegas EO, Sánchez-García FJ. A Role For Mitochondria In Antigen Processing And Presentation. Immunology 2014; 144:461-471. [PMID: 25251370 PMCID: PMC4557683 DOI: 10.1111/imm.12392] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 09/18/2014] [Accepted: 09/19/2014] [Indexed: 12/15/2022] Open
Abstract
Immune synapse formation is critical for T lymphocyte activation, and mitochondria have a role in this process, by localizing close to the immune synapse, regulating intracellular calcium concentration, and providing locally required ATP. The interaction between antigen presenting cells (APCs) and T lymphocytes is a two-way signaling process. However, the role of mitochondria in antigen presenting cells during this process remains unknown. For APCs to be able to activate T lymphocytes, they must first engage in an antigen-uptake, -processing, and -presentation process. Here we show that HEL-loaded B lymphocytes, as a type of APCs, undergo a small but significant mitochondrial depolarization by 1-2 h following antigen exposure thus suggesting an increase in their metabolic demands. Inhibition of ATP synthase (oligomycin) or mitochondrial Ca2+ uniporter (MCU) (Ruthenium red) had no effect on antigen uptake. Therefore, antigen processing and antigen presentation were further analyzed. Oligomycin treatment reduced the amount of specific MHC-peptide complexes but not total MHC II on the cell membrane of B lymphocytes which correlated with a decrease in antigen presentation. However, oligomycin also reduced antigen presentation by B lymphocytes that endogenously express HEL and by B lymphocytes loaded with the HEL48-62 peptide, although to a lesser extent. ATP synthase inhibition and MCU inhibition had a clear inhibitory effect on antigen processing (DQ-OVA). Taking together these results suggest that ATP synthase and MCU are relevant for antigen processing and presentation. Finally, APCs mitochondria were found to re-organize towards the APC-T immune synapse. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Laura C Bonifaz
- Unidad de Investigación Médica en Inmunoquímica, Hospital de especialidades, Instituto Mexicano del Seguro SocialMéxico, D.F., México
| | - Mariana P Cervantes-Silva
- Unidad de Investigación Médica en Inmunoquímica, Hospital de especialidades, Instituto Mexicano del Seguro SocialMéxico, D.F., México
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico NacionalMéxico, D.F., México
| | - Elizabeth Ontiveros-Dotor
- Unidad de Investigación Médica en Inmunoquímica, Hospital de especialidades, Instituto Mexicano del Seguro SocialMéxico, D.F., México
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico NacionalMéxico, D.F., México
| | - Edgar O López-Villegas
- Central de Microscopía, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico NacionalMéxico, D.F., México
| | - F Javier Sánchez-García
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico NacionalMéxico, D.F., México
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23
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Choi JG, Mun SH, Chahar HS, Bharaj P, Kang OH, Kim SG, Shin DW, Kwon DY. Methyl gallate from Galla rhois successfully controls clinical isolates of Salmonella infection in both in vitro and in vivo systems. PLoS One 2014; 9:e102697. [PMID: 25048362 PMCID: PMC4105534 DOI: 10.1371/journal.pone.0102697] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 06/22/2014] [Indexed: 12/03/2022] Open
Abstract
Galla rhois is a commonly used traditional medicine for the treatment of pathogenic bacteria in Korea as well as in other parts of Asia. Methyl gallate (MG), a major component of Galla Rhois, exhibits strong antibacterial activity, but its mechanism of action against Salmonella spp. is unclear. In the present study, we investigated the antibacterial actions of MG against Salmonella. The antibacterial activity determined by broth dilution method indicated that the antibacterial activity of MG against Salmonella strains ranged from 3.9 to 125 µg/ml. In vitro bacterial viability test indicated that MG significantly decreased the viability of Salmonella over 40% when combined with ATPase inhibitors. The time-kill curves showed that a combined MG and ATPase inhibitors (DCCD and NaN3) treatment reduced the bacterial counts dramatically after 24 h. Oral administration of MG showed a strong anti-bacterial activity against WS-5 infected BALB/c mice. In contrast to the untreated Salmonella infected control animals, MG treated groups showed no clinical symptoms of the disease, such as lethargy and liver damage. It was observed that MG treatment significantly increased the survival of animals from Salmonella infection, while in untreated groups all animal succumbed to disease by the sixth day post infection. Thus, the present study demonstrates the therapeutic ability of MG against Salmonella infections.
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Affiliation(s)
- Jang-Gi Choi
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang University, Wonkwang Oriental Medicines Research Institute, Institute of Biotechnology, Jeonbuk, Korea
- Center of Excellence in Infectious Disease Research, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, United States of America
| | - Su-Hyun Mun
- BK21 Plus Team, Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk, Republic of Korea
| | - Harendra S. Chahar
- Center of Excellence in Infectious Disease Research, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, United States of America
| | - Preeti Bharaj
- Center of Excellence in Infectious Disease Research, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, United States of America
| | - Ok-Hwa Kang
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang University, Wonkwang Oriental Medicines Research Institute, Institute of Biotechnology, Jeonbuk, Korea
| | - Se-Gun Kim
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang University, Wonkwang Oriental Medicines Research Institute, Institute of Biotechnology, Jeonbuk, Korea
| | - Dong-Won Shin
- Department of Oriental Medicine Resources, Sunchon National University, Jeonnam, Republic of Korea
| | - Dong-Yeul Kwon
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang University, Wonkwang Oriental Medicines Research Institute, Institute of Biotechnology, Jeonbuk, Korea
- * E-mail:
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24
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The Antibacterial Assay of Tectorigenin with Detergents or ATPase Inhibitors against Methicillin-Resistant Staphylococcus aureus. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:716509. [PMID: 24987433 PMCID: PMC4058531 DOI: 10.1155/2014/716509] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 04/22/2014] [Accepted: 04/29/2014] [Indexed: 11/23/2022]
Abstract
Tectorigenin (TTR) is an O-methylated isoflavone derived from the rhizome of Belamacanda chinensis (L.) DC. It is known to perform a wide spectrum of biological activities such as antioxidant, anti-inflammatory, anti-tumor. The aim of this study is to examine the mechanism of antibacterial activity of TTR against methicillin-resistant Staphylococcus aureus (MRSA). The anti-MRSA activity of TTR was analyzed in combination assays with detergent, ATPase inhibitors, and peptidoglycan (PGN) derived from S. aureus. Transmission electron microscopy (TEM) was used to monitor survival characteristics and changes in S. aureus morphology. The MIC values of TTR against all the tested strains were 125 μg/mL. The OD(600) of each suspension treated with a combination of Triton X-100, DCCD, and NaN3 with TTR (1/10 × MIC) had been reduced from 68% to 80%, compared to the TTR alone. At a concentration of 125 μg/mL, PGN blocked antibacterial activity of TTR. This study indicates that anti-MRSA action of TTR is closely related to cytoplasmic membrane permeability and ABC transporter, and PGN at 125 μg/mL directly bind to and inhibit TTR at 62.5 μg/mL. These results can be important indication in study on antimicrobial activity mechanism against multidrug resistant strains.
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25
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Dutt Konar A, Vass E, Hollósi M, Majer Z, Grüber G, Frese K, Sewald N. Conformational properties of secondary amino acids: replacement of pipecolic acid by N-methyl-l-alanine in efrapeptin C. Chem Biodivers 2013; 10:942-51. [PMID: 23681735 DOI: 10.1002/cbdv.201300086] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Indexed: 11/08/2022]
Abstract
The efrapeptins, a family of naturally occurring peptides with inhibitory activities against ATPases, contain several α,α-disubstituted α-amino acids such as α-aminoisobutyric acid (Aib) or isovaline (Iva) besides pipecolic acid (Pip), β-Ala, Leu, Gly, and a C-terminal heterocyclic residue. Secondary α-amino acids such as proline are known to stabilize discrete conformations in peptides. A similar influence is ascribed to N-alkyl α-amino acids. We synthesized two efrapeptin C analogs with replacement of Pip by N-methyl-L-alanine (MeAla) using a combination of solid- and solution-phase techniques in a fragment-condensation strategy to compare the conformational bias of both secondary amino acids. The solution conformation was investigated by vibrational circular dichroism (VCD) to probe whether the analogs adopt a 310 -helical conformation. The MeAla-containing analogs [MeAla(1,3) ]efrapeptin C and [MeAla(1,3,11) ]efrapeptin C inhibit ATP hydrolysis by the A3 B3 complex of A1 A0 -ATP synthase from Methanosarcina mazei Gö1.
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26
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Beauvieux MC, Stephant A, Gin H, Serhan N, Couzigou P, Gallis JL. Resveratrol mainly stimulates the glycolytic ATP synthesis flux and not the mitochondrial one: a saturation transfer NMR study in perfused and isolated rat liver. Pharmacol Res 2013; 78:11-7. [PMID: 24090928 DOI: 10.1016/j.phrs.2013.09.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 09/08/2013] [Accepted: 09/15/2013] [Indexed: 12/19/2022]
Abstract
Our aim was to monitor the effects of resveratrol (RSV) on the respective contribution of glycolysis and oxidative phosphorylation on the unidirectional flux of ATP synthesis in whole isolated rat liver perfused with Krebs-Henseleit Buffer (KHB). The rate of tissular ATP supply was measured directly by monitoring the chemical exchange Pi toward ATP with saturation transfer (ST) (31)P nuclear magnetic resonance, a method applied for the first time for studying the effects of RSV. ST allows the measurement of the total cellular Pi→ATP chemical exchange; after specific inhibition of glycolysis with iodacetate, ST could provide the Pi→ATP flux issued from mitochondria. This latter was compared to mitochondrial ATP turn-over evaluated after chemical ischemia (CI), performed with specific inhibition (KCN) of oxidative phosphorylation, and measured by standard (31)P NMR spectroscopy. In controls (KHB alone), the apparent time constant (ks) of Pi exchange toward ATP as measured by ST was 0.48±0.04s(-1) leading to a total ATP synthesis rate of 37±3.9μmolmin(-1)g(-1). KHB+RSV perfusion increased ks (+52%; p=0.0009 vs. KHB) leading to an enhanced rate of total ATP synthesis (+52%; p=0.01 vs. KHB). When glycolysis was previously inhibited in KHB, both ks and ATP synthesis flux dramatically decreased (-87% and -86%, respectively, p<0.0001 vs. KHB without inhibition), evidencing a collapse of Pi-to-ATP exchange. However, glycolysis inhibition in KHB+RSV reduced to less extent ks (-41%, p=0.0005 vs. KHB+RSV without inhibition) and ATP synthesis flux (-18%). Using the CI method in KHB and KHB+RSV, KCN addition after glycolysis inhibition induced a rapid fall to zero of the ATP content. The mitochondrial ATP turnover R(t0) and its time constant kd mito were similar in KHB (1.18±0.19μmolmin(-1)g(-1) and 0.91±0.13min(-1)) and KHB+RSV (1.36±0.26μmolmin(-1)g(-1) and 0.77±0.18min(-1)). Since mitochondrial ATP turnover was not increased by RSV, the stimulation of Pi-to-ATP exchange by RSV mainly reflected an increase in glycolytic ATP synthesis flux. Moreover, the maintenance by RSV of a high level of Pi-to-ATP exchange after glycolysis inhibition evidenced a protective effect of the polyphenol, in agreement with our previous hypothesis of a stimulation of substrate flux throughout the glycolysis 3-carbon step.
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Affiliation(s)
- Marie-Christine Beauvieux
- Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS-Université, Bordeaux Segalen, LabEx TRAIL-IBIO, 146 rue Léo Saignat, F-33076 Bordeaux Cedex, France.
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Yim HK, Lim MN, Lee SE, Lim J, Lee Y, Hwang YS. Hexokinase-mediated sugar signaling controls expression of the calcineurin B-like interacting protein kinase 15 gene and is perturbed by oxidative phosphorylation inhibition. JOURNAL OF PLANT PHYSIOLOGY 2012; 169:1551-8. [PMID: 22796010 DOI: 10.1016/j.jplph.2012.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 06/14/2012] [Accepted: 06/15/2012] [Indexed: 05/08/2023]
Abstract
Calcineurin B-like (CBL) interacting protein kinase 15 (CIPK15) is a newly identified positive regulator which is critical to directing the O(2) deficiency signal to the sugar signaling cascade as part of Amy3D (representative Amy3 gene) regulation in rice. It is located upstream and probably contributes to reserve mobilization under anoxia. In isolated starving embryos, the temporal pattern of accumulation of CIPK15 transcripts and leaky suppression of this gene suggests that factors other than CIPK15 may also be involved in the regulation of Amy3D expression. Probing of a variety of sugars and sugar analogs has shown that hexokinase mediates the sugar regulation of CIPK15. For example, hexokinase substrates, such as mannose, 2-deoxyglucose, and other metabolizable sugars, repressed CIPK15 expression, whereas 3-O-methylglucose and 6-deoxyglucose did not. By using glucosamine, a hexokinase inhibitor, to release glucose-dependent CIPK15 suppression, we confirmed that hexokinase mediates regulation of this gene. Chemical inhibitors of mitochondrial electron transfer, proton separation or ATP synthase also effectively abolished sugar-induced repression of CIPK15. This type of interference, the release from glucose-induced repression of gene expression by inhibition of oxidative phosphorylation, was previously identified for the Amy3D gene, which suggests that hexokinase-mediated sugar signaling may be coordinated with the cellular energy status. Analysis of a transgenic rice cell line harboring the GUS reporter gene under the control of the CIPK15 promoter, and transient expression assay for 3' UTR of the CIPK15 gene indicate that sugar regulation of the rice CIPK15 gene is likely mediated by 2548-bp 5'-flanking region, with no additional post-transcriptional control.
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Affiliation(s)
- Hui-Kyeong Yim
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, Republic of Korea
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Hwang IS, Hwang JH, Choi H, Kim KJ, Lee DG. Synergistic effects between silver nanoparticles and antibiotics and the mechanisms involved. J Med Microbiol 2012; 61:1719-1726. [PMID: 22956753 DOI: 10.1099/jmm.0.047100-0] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Silver nanoparticles (nano-Ags), which have well-known antimicrobial properties, are used extensively in various medical and general applications. In this study, the combination effects between nano-Ags and the conventional antibiotics ampicillin, chloramphenicol and kanamycin against various pathogenic bacteria were investigated. The MIC and fractional inhibitory concentration index (FICI) were determined to confirm antibacterial susceptibility and synergistic effects. The results showed that nano-Ags possessed antibacterial effects and synergistic activities. The antibiofilm activities of nano-Ags alone or in combination with antibiotics were also investigated. Formation of biofilm is associated with resistance to antimicrobial agents and chronic bacterial infections. The results indicated that nano-Ags also had antibiofilm activities. To understand these effects of nano-Ags, an ATPase inhibitor assay, permeability assay and hydroxyl radical assay were conducted. The antibacterial activity of nano-Ags was influenced by ATP-associated metabolism rather than by the permeability of the outer membrane. Additionally, nano-Ags generated hydroxyl radicals, a highly reactive oxygen species induced by bactericidal agents. It was concluded that nano-Ags have potential as a combination therapeutic agent for the treatment of infectious diseases by bacteria.
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Affiliation(s)
- In-Sok Hwang
- School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Daehak-ro 80 Buk-gu Daegu, 702-701, Republic of Korea
| | - Ji Hong Hwang
- School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Daehak-ro 80 Buk-gu Daegu, 702-701, Republic of Korea
| | - Hyemin Choi
- School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Daehak-ro 80 Buk-gu Daegu, 702-701, Republic of Korea
| | - Keuk-Jun Kim
- Department of Clinical Pathology, Tae Kyeung College, 24, Danbuk-ri, Jain-myeon, Gyeongsan-si, Gyeongsangbuk-do, 712-719, Republic of Korea
| | - Dong Gun Lee
- School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Daehak-ro 80 Buk-gu Daegu, 702-701, Republic of Korea
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Lee YS, Han SH, Lee SH, Kim YG, Park CB, Kang OH, Keum JH, Kim SB, Mun SH, Seo YS, Myung NY, Kwon DY. The mechanism of antibacterial activity of tetrandrine against Staphylococcus aureus. Foodborne Pathog Dis 2012; 9:686-91. [PMID: 22845553 DOI: 10.1089/fpd.2011.1119] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Tetrandrine (TET) is a bis-benzylisoquinoline alkaloid derived from the radix of Stephania tetrandra S. Moore. TET performs a wide spectrum of biological activities. The radix of S. tetrandrae has been used traditionally in Asia, including Korea, to treat congestive circulatory disorders and inflammatory diseases. The aim of this study was to examine the mechanism of antibacterial activity of tetrandrine against Staphylococcus aureus. The mechanism was investigated by studying the effects of TET in combination with detergent or membrane potential un-couplers. In addition, the direct involvement of peptidoglycan (PGN) was assessed in titration assays. TET activity against S. aureus was 125-250 μg/mL, and the minimum inhibitory concentration (MIC) of the two reference strains was 250 μg/mL. The OD(600) of each suspension treated with a combination of ethylenediaminetetraacetic acid (EDTA), tris(hydroxymethyl) aminomethane (TRIS), and Triton X-100 (TX) with TET (0.25×MIC) had been reduced from 43% to 96%. Additional structure-function studies on the antibacterial activity of TET in combination with other agents may lead to the discovery of more effective antibacterial agents.
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Affiliation(s)
- Young-Seob Lee
- Department of Herbal Crop Research, National Institute of Horticultural & Herbal Science, Rural Development Administration, Eumsung, Chungbuk, Republic of Korea
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Subba Reddy B, Narasimhulu G, Vikram Reddy Y, Chakravarthy P, Yadav J, Sridhar B. Sc(OTf)3/TsOH: a highly efficient catalytic system for the synthesis of 2,6-dioxabicyclo[3,2,1]octane derivatives. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.04.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Weigelt S, Huber T, Hofmann F, Jost M, Ritzefeld M, Luy B, Freudenberger C, Majer Z, Vass E, Greie JC, Panella L, Kaptein B, Broxterman QB, Kessler H, Altendorf K, Hollósi M, Sewald N. Synthesis and Conformational Analysis of Efrapeptins. Chemistry 2011; 18:478-87. [DOI: 10.1002/chem.201102134] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Indexed: 11/11/2022]
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Synthetic studies of venturicidins: stereoselective synthesis of the C15–C27 segment based on two types of stereospecific epoxide opening reactions. Tetrahedron Lett 2011. [DOI: 10.1016/j.tetlet.2011.10.073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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McMillan DGG, Ferguson SA, Dey D, Schröder K, Aung HL, Carbone V, Attwood GT, Ronimus RS, Meier T, Janssen PH, Cook GM. A1Ao-ATP synthase of Methanobrevibacter ruminantium couples sodium ions for ATP synthesis under physiological conditions. J Biol Chem 2011; 286:39882-92. [PMID: 21953465 DOI: 10.1074/jbc.m111.281675] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An unresolved question in the bioenergetics of methanogenic archaea is how the generation of proton-motive and sodium-motive forces during methane production is used to synthesize ATP by the membrane-bound A(1)A(o)-ATP synthase, with both proton- and sodium-coupled enzymes being reported in methanogens. To address this question, we investigated the biochemical characteristics of the A(1)A(o)-ATP synthase (MbbrA(1)A(o)) of Methanobrevibacter ruminantium M1, a predominant methanogen in the rumen. Growth of M. ruminantium M1 was inhibited by protonophores and sodium ionophores, demonstrating that both ion gradients were essential for growth. To study the role of these ions in ATP synthesis, the ahaHIKECFABD operon encoding the MbbrA(1)A(o) was expressed in Escherichia coli strain DK8 (Δatp) and purified yielding a 9-subunit protein with an SDS-stable c oligomer. Analysis of the c subunit amino acid sequence revealed that it consisted of four transmembrane helices, and each hairpin displayed a complete Na(+)-binding signature made up of identical amino acid residues. The purified MbbrA(1)A(o) was stimulated by sodium ions, and Na(+) provided pH-dependent protection against inhibition by dicyclohexylcarbodiimide but not tributyltin chloride. ATP synthesis in inverted membrane vesicles lacking sodium ions was driven by a membrane potential that was sensitive to cyanide m-chlorophenylhydrazone but not to monensin. ATP synthesis could not be driven by a chemical gradient of sodium ions unless a membrane potential was imposed. ATP synthesis under these conditions was sensitive to monensin but not cyanide m-chlorophenylhydrazone. These data suggest that the M. ruminantium M1 A(1)A(o)-ATP synthase exhibits all the properties of a sodium-coupled enzyme, but it is also able to use protons to drive ATP synthesis under conditions that favor proton coupling, such as low pH and low levels of sodium ions.
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Affiliation(s)
- Duncan G G McMillan
- Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago, Dunedin 9054, New Zealand
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Mesbah NM, Wiegel J. The Na(+)-translocating F₁F₀-ATPase from the halophilic, alkalithermophile Natranaerobius thermophilus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:1133-42. [PMID: 21600188 DOI: 10.1016/j.bbabio.2011.05.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Revised: 04/30/2011] [Accepted: 05/03/2011] [Indexed: 11/18/2022]
Abstract
Natranaerobius thermophilus is an unusual anaerobic extremophile, it is halophilic and alkalithermophilic; growing optimally at 3.3-3.9M Na(+), pH(50°C) 9.5 and 53°C. The ATPase of N. thermophilus was characterized at the biochemical level to ascertain its role in life under hypersaline, alkaline, thermal conditions. The partially purified enzyme (10-fold purification) displayed the typical subunit pattern for F-type ATPases, with a 5-subunit F(1) portion and 3-subunit-F(O) portion. ATP hydrolysis by the purified ATPase was stimulated almost 4-fold by low concentrations of Na(+) (5mM); hydrolysis activity was inhibited by higher Na(+) concentrations. Partially purified ATPase was alkaliphilic and thermophilic, showing maximal hydrolysis at 47°C and the alkaline pH(50°C) of 9.3. ATP hydrolysis was sensitive to the F-type ATPase inhibitor N,N'-dicylohexylcarbodiimide and exhibited inhibition by both free Mg(2+) and free ATP. ATP synthesis by inverted membrane vesicles proceeded slowly and was driven by a Na(+)-ion gradient that was sensitive to the Na(+)-ionophore monensin. Analysis of the atp operon showed the presence of the Na(+)-binding motif in the c subunit (Q(33), E(66), T(67), T(68), Y(71)), and a complete, untruncated ε subunit; suggesting that ATP hydrolysis by the enzyme is regulated. Based on these properties, the F(1)F(O)-ATPase of N. thermophilus is a Na(+)-translocating ATPase used primarily for expelling cytoplasmic Na(+) that accumulates inside cells of N. thermophilus during alkaline stress. In support of this theory are the presence of the c subunit Na(+)-binding motif and the low rates of ATP synthesis observed. The complete ε subunit is hypothesized to control excessive ATP hydrolysis and preserve intracellular Na(+) needed by electrogenic cation/proton antiporters crucial for cytoplasmic acidification in the obligately alkaliphilic N. thermophilus.
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Affiliation(s)
- Noha M Mesbah
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA.
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W Obiang-Obounou B, Kang OH, Choi JG, Keum JH, Kim SB, Mun SH, Shin DW, Woo Kim K, Park CB, Kim YG, Han SH, Kwon DY. The mechanism of action of sanguinarine against methicillin-resistant Staphylococcus aureus. J Toxicol Sci 2011; 36:277-83. [DOI: 10.2131/jts.36.277] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Brice W Obiang-Obounou
- Wonkwang University, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute
| | - Ok-Hwa Kang
- Wonkwang University, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute
- Kunsan National university, Department of Oceangraphy
| | - Jang-Gi Choi
- Wonkwang University, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute
| | - Joon-Ho Keum
- Wonkwang University, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute
| | - Sung-Bae Kim
- Wonkwang University, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute
| | - Su-Hyun Mun
- Wonkwang University, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute
| | - Dong-Won Shin
- Sunchon National University, Department of Oriental Medicine Resources
| | - Ki Woo Kim
- Kyungpook National University, School of Ecological and Environmental System
| | - Chung-Berm Park
- National Institute of Horticultural & Herbal Science, RDA, Department of Herbal Crop Research
| | - Young-Guk Kim
- National Institute of Horticultural & Herbal Science, RDA, Department of Herbal Crop Research
| | - Sin-Hee Han
- National Institute of Horticultural & Herbal Science, RDA, Department of Herbal Crop Research
| | - Dong-Yeul Kwon
- Wonkwang University, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute
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Soontharapirakkul K, Incharoensakdi A. Na+-stimulated ATPase of alkaliphilic halotolerant cyanobacterium Aphanothece halophytica translocates Na+ into proteoliposomes via Na+ uniport mechanism. BMC BIOCHEMISTRY 2010; 11:30. [PMID: 20691102 PMCID: PMC2928168 DOI: 10.1186/1471-2091-11-30] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 08/07/2010] [Indexed: 11/10/2022]
Abstract
Background When cells are exposed to high salinity conditions, they develop a mechanism to extrude excess Na+ from cells to maintain the cytoplasmic Na+ concentration. Until now, the ATPase involved in Na+ transport in cyanobacteria has not been characterized. Here, the characterization of ATPase and its role in Na+ transport of alkaliphilic halotolerant Aphanothece halophytica were investigated to understand the survival mechanism of A. halophytica under high salinity conditions. Results The purified enzyme catalyzed the hydrolysis of ATP in the presence of Na+ but not K+, Li+ and Ca2+. The apparent Km values for Na+ and ATP were 2.0 and 1.2 mM, respectively. The enzyme is likely the F1F0-ATPase based on the usual subunit pattern and the protection against N,N'-dicyclohexylcarbodiimide inhibition of ATPase activity by Na+ in a pH-dependent manner. Proteoliposomes reconstituted with the purified enzyme could take up Na+ upon the addition of ATP. The apparent Km values for this uptake were 3.3 and 0.5 mM for Na+ and ATP, respectively. The mechanism of Na+ transport mediated by Na+-stimulated ATPase in A. halophytica was revealed. Using acridine orange as a probe, alkalization of the lumen of proteoliposomes reconstituted with Na+-stimulated ATPase was observed upon the addition of ATP with Na+ but not with K+, Li+ and Ca2+. The Na+- and ATP-dependent alkalization of the proteoliposome lumen was stimulated by carbonyl cyanide m - chlorophenylhydrazone (CCCP) but was inhibited by a permeant anion nitrate. The proteoliposomes showed both ATPase activity and ATP-dependent Na+ uptake activity. The uptake of Na+ was enhanced by CCCP and nitrate. On the other hand, both CCCP and nitrate were shown to dissipate the preformed electric potential generated by Na+-stimulated ATPase of the proteoliposomes. Conclusion The data demonstrate that Na+-stimulated ATPase from A. halophytica, a likely member of F-type ATPase, functions as an electrogenic Na+ pump which transports only Na+ upon hydrolysis of ATP. A secondary event, Na+- and ATP-dependent H+ efflux from proteoliposomes, is driven by the electric potential generated by Na+-stimulated ATPase.
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Sen SS, Bhuyan NR, Lakshman K, Roy AK, Chakraborty B, Bera T. Membrane bound pyrophosphatase and P-type adenosine triphosphatase of Leishmania donovani as possible chemotherapeutic targets: similarities and differences in inhibitor sensitivities. BIOCHEMISTRY. BIOKHIMIIA 2009; 74:1382-7. [PMID: 19961421 DOI: 10.1134/s000629790912013x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The activities of inorganic pyrophosphatase (PPase) and adenosine triphosphatase (ATPase) were studied in the plasma membrane of Leishmania donovani promastigotes and amastigotes. It was shown that the specific activity of PPase was greater than that of ATPase in the promastigote plasma membrane. We characterized H+-PPase present in the plasma membrane of L. donovani and investigated its possible role in the survival of promastigote and amastigote. PPase activity was stimulated by K+ and sodium orthovanadate and inhibited by pyrophosphate analogs (imidodiphosphate and alendronate), KF, N,N'-dicyclohexylcarbodiimide (DCCD), thiol reagents (p-chloromercuribenzenesulfonate (PCMBS), N-ethylmaleimide (NEM), and phenylarsine oxide (PAO)), the ABC superfamily transport modulator verapamil, and also by the F(1)F(o)-ATPase inhibitor quercetin. ATPase activity was stimulated by K+ and verapamil, inhibited by DCCD, PCMBS, NEM, sodium azide, sodium orthovanadate, and quercetin, and was unaffected by PAO. We conclude that there are significant differences within promastigote, amastigote, and mammalian host in cytosolic pH homeostasis to merit the inclusion of PPase transporter as a putative target for rational drug design.
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Affiliation(s)
- S S Sen
- Division of Medicinal Biochemistry, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, 7000032, India
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Johnson KM, Swenson L, Opipari AW, Reuter R, Zarrabi N, Fierke CA, Börsch M, Glick GD. Mechanistic basis for differential inhibition of the F1Fo-ATPase by aurovertin. Biopolymers 2009; 91:830-40. [PMID: 19462418 DOI: 10.1002/bip.21262] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The mitochondrial F(1)F(o)-ATPase performs the terminal step of oxidative phosphorylation. Small molecules that modulate this enzyme have been invaluable in helping decipher F(1)F(o)-ATPase structure, function, and mechanism. Aurovertin is an antibiotic that binds to the beta subunits in the F(1) domain and inhibits F(1)F(o)-ATPase-catalyzed ATP synthesis in preference to ATP hydrolysis. Despite extensive study and the existence of crystallographic data, the molecular basis of the differential inhibition and kinetic mechanism of inhibition of ATP synthesis by aurovertin has not been resolved. To address these questions, we conducted a series of experiments in both bovine heart mitochondria and E. coli membrane F(1)F(o)-ATPase. Aurovertin is a mixed, noncompetitive inhibitor of both ATP hydrolysis and synthesis with lower K(i) values for synthesis. At low substrate concentrations, inhibition is cooperative suggesting a stoichiometry of two aurovertin per F(1)F(o)-ATPase. Furthermore, aurovertin does not completely inhibit the ATP hydrolytic activity at saturating concentrations. Single-molecule experiments provide evidence that the residual rate of ATP hydrolysis seen in the presence of saturating concentrations of aurovertin results from a decrease in the binding change mechanism by hindering catalytic site interactions. The results from these studies should further the understanding of how the F(1)F(o)-ATPase catalyzes ATP synthesis and hydrolysis.
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Affiliation(s)
- Kathryn M Johnson
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
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Zhou ZY, Liu R, Jiang MY, Zhang L, Niu Y, Zhu YC, Dong ZJ, Liu JK. Two New Cleistanthane Diterpenes and a New Isocoumarine from Cultures of the Basidiomycete Albatrellus confluens. Chem Pharm Bull (Tokyo) 2009; 57:975-8. [PMID: 19721259 DOI: 10.1248/cpb.57.975] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Zhong-Yu Zhou
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences
- Graduate School of the Chinese Academy of Sciences
| | - Rong Liu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences
- Graduate School of the Chinese Academy of Sciences
| | - Meng-Yuan Jiang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences
- Graduate School of the Chinese Academy of Sciences
| | - Ling Zhang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences
- Graduate School of the Chinese Academy of Sciences
| | - Yun Niu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences
- Graduate School of the Chinese Academy of Sciences
| | - Ying-Cheng Zhu
- Anhui Key Laboratory of Modernized Chinese Materia Medica, Anhui College of Traditional Chinese Medicine
| | - Ze-Jun Dong
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences
| | - Ji-Kai Liu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences
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Hong S, Pedersen PL. ATP synthase and the actions of inhibitors utilized to study its roles in human health, disease, and other scientific areas. Microbiol Mol Biol Rev 2008; 72:590-641, Table of Contents. [PMID: 19052322 PMCID: PMC2593570 DOI: 10.1128/mmbr.00016-08] [Citation(s) in RCA: 236] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
ATP synthase, a double-motor enzyme, plays various roles in the cell, participating not only in ATP synthesis but in ATP hydrolysis-dependent processes and in the regulation of a proton gradient across some membrane-dependent systems. Recent studies of ATP synthase as a potential molecular target for the treatment of some human diseases have displayed promising results, and this enzyme is now emerging as an attractive molecular target for the development of new therapies for a variety of diseases. Significantly, ATP synthase, because of its complex structure, is inhibited by a number of different inhibitors and provides diverse possibilities in the development of new ATP synthase-directed agents. In this review, we classify over 250 natural and synthetic inhibitors of ATP synthase reported to date and present their inhibitory sites and their known or proposed modes of action. The rich source of ATP synthase inhibitors and their known or purported sites of action presented in this review should provide valuable insights into their applications as potential scaffolds for new therapeutics for human and animal diseases as well as for the discovery of new pesticides and herbicides to help protect the world's food supply. Finally, as ATP synthase is now known to consist of two unique nanomotors involved in making ATP from ADP and P(i), the information provided in this review may greatly assist those investigators entering the emerging field of nanotechnology.
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Affiliation(s)
- Sangjin Hong
- Department of Biological Chemistry, Johns Hopkins University, School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205-2185, USA
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Jung HJ, Lee DG. Synergistic antibacterial effect between silybin and N,N'-dicyclohexylcarbodiimide in clinical Pseudomonas aeruginosa isolates. J Microbiol 2008; 46:462-7. [PMID: 18758739 DOI: 10.1007/s12275-008-0138-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Accepted: 06/24/2008] [Indexed: 12/01/2022]
Abstract
Silybin is a composition of the silymarin group as a hepatoprotective agent, and it exhibits various biological activities, including an antibacterial activity. In this study, the effects of a combination of silybin with N,N'-dicyclohexylcarbodiimide (DCCD) against clinical isolates of Pseudomonas aeruginosa were investigated. In the results of susceptibility assay, silybin showed more potent antibacterial activity in methicillin-resistant Staphylococcus aureus (MRSA) than in P. aeruginosa, but DCCD significantly increased the antibacterial activity of silybin in P. aeruginosa. The antibacterial activity of silybin was affected by the strong action of multidrug-resistant pumps rather than by a permeable disruption of lipopolysaccharide and silybin showed a remarkable synergistic activity in combination with some antibiotic agents against drug-resistant bacteria. Therefore, silybin has a potential as a combination therapeutic agent for treatment of infectious diseases by multidrug-resistant bacteria.
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Affiliation(s)
- Hyun Jun Jung
- Department of Microbiology, College of Natural Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea
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43
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Ulanovskaya OA, Janjic J, Suzuki M, Sabharwal SS, Schumacker PT, Kron SJ, Kozmin SA. Synthesis enables identification of the cellular target of leucascandrolide A and neopeltolide. Nat Chem Biol 2008; 4:418-24. [PMID: 18516048 PMCID: PMC2673112 DOI: 10.1038/nchembio.94] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Accepted: 05/12/2008] [Indexed: 11/09/2022]
Abstract
Leucascandrolide A and neopeltolide are structurally homologous marine natural products that elicit potent antiproliferative profiles in mammalian cells and yeast. The scarcity of naturally available material has been a significant barrier to their biochemical and pharmacological evaluation. We developed practical synthetic access to this class of natural products that enabled the determination of their mechanism of action. We demonstrated effective cellular growth inhibition in yeast, which was substantially enhanced by substituting glucose with galactose or glycerol. These results, along with genetic analysis of determinants of drug sensitivity, suggested that leucascandrolide A and neopeltolide may inhibit mitochondrial ATP synthesis. Evaluation of the activity of the four mitochondrial electron transport chain complexes in yeast and mammalian cells revealed cytochrome bc(1) complex as the principal cellular target. This result provided the molecular basis for the potent antiproliferative activity of this class of marine macrolides, thus identifying them as new biochemical tools for investigation of eukaryotic energy metabolism.
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Affiliation(s)
- Olesya A Ulanovskaya
- Department of Chemistry, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA
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44
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Mammalian mitochondria have the innate ability to import tRNAs by a mechanism distinct from protein import. Proc Natl Acad Sci U S A 2008; 105:9186-91. [PMID: 18587046 DOI: 10.1073/pnas.0804283105] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial genomes generally encode a minimal set of tRNAs necessary for protein synthesis. However, a number of eukaryotes import tRNAs from the cytoplasm into their mitochondria. For instance, Saccharomyces cerevisiae imports cytoplasmic tRNA(Gln) into the mitochondrion without any added protein factors. Here, we examine the existence of a similar active tRNA import system in mammalian mitochondria. We have used subcellular RNA fractions from rat liver and human cells to perform RT-PCR with oligonucleotide primers specific for nucleus-encoded tRNA(CUG)(Gln) and tRNA(UUG)(Gln) species, and we show that these tRNAs are present in rat and human mitochondria in vivo. Import of in vitro transcribed tRNAs, but not of heterologous RNAs, into isolated mitochondria also demonstrates that this process is tRNA-specific and does not require the addition of cytosolic factors. Although this in vitro system requires ATP, it is resistant to inhibitors of the mitochondrial electrochemical gradient, a key component of protein import. tRNA(Gln) import into mammalian mitochondria proceeds by a mechanism distinct from protein import. We also show that both tRNA(Gln) species and a bacterial pre-tRNA(Asp) can be imported in vitro into mitochondria isolated from myoclonic epilepsy with ragged-red fiber cells if provided with sufficient ATP (2 mM). This work suggests that tRNA import is more widespread than previously thought and may be a universal trait of mitochondria. Mutations in mitochondrial tRNA genes have been associated with human disease; the tRNA import system described here could possibly be exploited for the manipulation of defective mitochondria.
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45
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Ling YH, Lin R, Perez-Soler R. RETRACTION: Erlotinib Induces Mitochondrial-Mediated Apoptosis in Human H3255 Non-Small-Cell Lung Cancer Cells with Epidermal Growth Factor ReceptorL858R Mutation through Mitochondrial Oxidative Phosphorylation-Dependent Activation of BAX and BAK. Mol Pharmacol 2008; 74:793-806. [DOI: 10.1124/mol.107.044396] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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46
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McLoughlin A, Vallom J. The influence of ionic gradients on flocculation ofBrevibacteriumsp. ACTA ACUST UNITED AC 2008. [DOI: 10.1111/j.1365-2672.1984.tb01414.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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47
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Feniouk BA, Rebecchi A, Giovannini D, Anefors S, Mulkidjanian AY, Junge W, Turina P, Melandri BA. Met23Lys mutation in subunit gamma of F(O)F(1)-ATP synthase from Rhodobacter capsulatus impairs the activation of ATP hydrolysis by protonmotive force. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:1319-30. [PMID: 17904517 DOI: 10.1016/j.bbabio.2007.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 07/18/2007] [Accepted: 07/19/2007] [Indexed: 11/26/2022]
Abstract
H(+)-F(O)F(1)-ATP synthase couples proton flow through its membrane portion, F(O), to the synthesis of ATP in its headpiece, F(1). Upon reversal of the reaction the enzyme functions as a proton pumping ATPase. Even in the simplest bacterial enzyme the ATPase activity is regulated by several mechanisms, involving inhibition by MgADP, conformational transitions of the epsilon subunit, and activation by protonmotive force. Here we report that the Met23Lys mutation in the gamma subunit of the Rhodobacter capsulatus ATP synthase significantly impaired the activation of ATP hydrolysis by protonmotive force. The impairment in the mutant was due to faster enzyme deactivation that was particularly evident at low ATP/ADP ratio. We suggest that the electrostatic interaction of the introduced gammaLys23 with the DELSEED region of subunit beta stabilized the ADP-inhibited state of the enzyme by hindering the rotation of subunit gamma rotation which is necessary for the activation.
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Affiliation(s)
- Boris A Feniouk
- Division of Biophysics, School of Biology/Chemistry, University of Osnabrück, D-49069, Osnabrück, Germany.
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48
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Soares SS, Gutiérrez-Merino C, Aureliano M. Mitochondria as a target for decavanadate toxicity in Sparus aurata heart. AQUATIC TOXICOLOGY 2007; 83:1-9. [PMID: 17420061 DOI: 10.1016/j.aquatox.2007.03.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 03/07/2007] [Accepted: 03/08/2007] [Indexed: 02/07/2023]
Abstract
In a previous in vivo study we have reported that vanadium distribution, antioxidant enzymes activity and lipid peroxidation in Sparus aurata heart are strongly dependent on the oligomeric vanadate species being administered. Moreover, it was suggested that vanadium is accumulated in mitochondria, in particular when V10 was intravenously injected. In this work we have done a comparative study of the effects of V10 and monomeric vanadate (V1) on cardiac mitochondria from S. aurata. V10 inhibits mitochondrial oxygen consumption with an IC(50) of 400 nM, while the IC(50) for V1 is 23 microM. V10 also induced mitochondrial depolarization at very low concentrations, with an IC(50) of 196 nM, and 55 microM of V1 was required to induce the same effect. Additionally, up to 5 microM V10 did inhibit neither F(0)F(1)-ATPase activity nor NADH levels and it did not affect respiratory complexes I and II, but it induced changes in the redox steady-state of complex III. It is concluded that V10 inhibits mitochondrial oxygen consumption and induces membrane depolarization more strongly than V1, pointing out that mitochondria is a toxicological target for V10 and the importance to take into account the contribution of V10 to the vanadate toxic effects.
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Affiliation(s)
- Sandra S Soares
- Faculty of Sciences and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
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49
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McCallum JR, McCarty RE. Proton flux through the chloroplast ATP synthase is altered by cleavage of its gamma subunit. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:974-9. [PMID: 17559799 DOI: 10.1016/j.bbabio.2007.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 04/02/2007] [Accepted: 04/23/2007] [Indexed: 11/21/2022]
Abstract
Electron transport, the proton gradient and ATP synthesis were determined in thylakoids that had been briefly exposed to a low concentration of trypsin during illumination. This treatment cleaves the gamma subunit of the ATP synthase into two large fragments that remain associated with the enzyme. Higher rates of electron transport are required to generate a given value of the proton gradient in the trypsin-treated membranes than in control membranes, indicating that the treated membranes are proton leaky. Since venturicidin restores electron transport and the proton gradient to control levels, the proton leak is through the ATP synthase. Remarkably, the synthesis of ATP by the trypsin-treated membranes at saturating light intensities is only slightly inhibited even though the proton gradient is significantly lower in the treated thylakoids. ATP synthesis and the proton gradient were determined as a function of light intensity in control and trypsin-treated thylakoids. The trypsin-treated membranes synthesized ATP at lower values of the proton gradient than the control membranes. Cleavage of the gamma subunit abrogates inhibition of the activity of the chloroplast ATP synthase by the epsilon subunit. Our results suggest that overcoming inhibition by the epsilon subunit costs energy.
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Affiliation(s)
- Jeremy R McCallum
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, USA
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50
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Fabre ACS, Vantourout P, Champagne E, Tercé F, Rolland C, Perret B, Collet X, Barbaras R, Martinez LO. Cell surface adenylate kinase activity regulates the F(1)-ATPase/P2Y (13)-mediated HDL endocytosis pathway on human hepatocytes. Cell Mol Life Sci 2006; 63:2829-37. [PMID: 17103109 PMCID: PMC2020515 DOI: 10.1007/s00018-006-6325-y] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
We have previously demonstrated on human hepatocytes that apolipoprotein A-I binding to an ecto-F(1)-ATPase stimulates the production of extracellular ADP that activates a P2Y(13)-mediated high-density lipoprotein (HDL) endocytosis pathway. Therefore, we investigated the mechanisms controlling the extracellular ATP/ADP level in hepatic cell lines and primary cultures to determine their impact on HDL endocytosis. Here we show that addition of ADP to the cell culture medium induced extracellular ATP production that was due to adenylate kinase [see text] and nucleoside diphosphokinase [see text] activities, but not to ATP synthase activity. We further observed that in vitro modulation of both ecto-NDPK and AK activities could regulate the ADP-dependent HDL endocytosis. But interestingly, only AK appeared to naturally participate in the pathway by consuming the ADP generated by the ecto-F(1)-ATPase. Thus controlling the extracellular ADP level is a potential target for reverse cholesterol transport regulation.
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Affiliation(s)
- A. C. S. Fabre
- INSERM U563, Département LML Bat. C, Hôpital Purpan, BP 3048, 31024 Toulouse cedex 03, France
| | - P. Vantourout
- INSERM U563, Département LML Bat. C, Hôpital Purpan, BP 3048, 31024 Toulouse cedex 03, France
| | - E. Champagne
- INSERM U563, Département LML Bat. C, Hôpital Purpan, BP 3048, 31024 Toulouse cedex 03, France
| | - F. Tercé
- INSERM U563, Département LML Bat. C, Hôpital Purpan, BP 3048, 31024 Toulouse cedex 03, France
| | - C. Rolland
- INSERM U563, Département LML Bat. C, Hôpital Purpan, BP 3048, 31024 Toulouse cedex 03, France
| | - B. Perret
- INSERM U563, Département LML Bat. C, Hôpital Purpan, BP 3048, 31024 Toulouse cedex 03, France
| | - X. Collet
- INSERM U563, Département LML Bat. C, Hôpital Purpan, BP 3048, 31024 Toulouse cedex 03, France
| | - R. Barbaras
- INSERM U563, Département LML Bat. C, Hôpital Purpan, BP 3048, 31024 Toulouse cedex 03, France
| | - L. O. Martinez
- INSERM U563, Département LML Bat. C, Hôpital Purpan, BP 3048, 31024 Toulouse cedex 03, France
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