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Characterization of the part of N-terminal PIP2 binding site of the TRPM1 channel. Biophys Chem 2015; 207:135-42. [DOI: 10.1016/j.bpc.2015.10.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 10/23/2015] [Accepted: 10/25/2015] [Indexed: 11/19/2022]
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Wang JM, Chu Y, Li W, Wang XY, Guo JH, Yan LL, Ma XH, Ma YL, Yin QH, Liu CX. Simultaneous determination of creatine phosphate, creatine and 12 nucleotides in rat heart by LC-MS/MS. J Chromatogr B Analyt Technol Biomed Life Sci 2014; 958:96-101. [PMID: 24705537 DOI: 10.1016/j.jchromb.2014.03.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 01/27/2014] [Accepted: 03/05/2014] [Indexed: 11/18/2022]
Abstract
A simple, rapid and sensitive LC-MS/MS method was developed and validated for simultaneous determination of creatine phosphate (CP), creatine (Cr) and 12 nucleotides in rat heart. The analytes, ATP, ADP, AMP, GTP, GDP, GMP, CTP, CDP, CMP, UTP, UDP, UMP, CP, Cr, were extracted from heart tissue with pre-cooled (0°C) methanol/water (1:1, v/v) and separated on a Hypersil Gold AQ C18 column (150mm×4.6mm, 3μm) using an isocratic elution with a mobile phase consisting of 2mmol/L ammonium acetate in water (pH 10.0, adjusted with ammonia). The detection was performed by negative ion electrospray ionization in selective reaction monitoring mode (SRM). In the assay, all the analytes showed good linearity over the investigated concentration range (r>0.99). The accuracy was between 80.7% and 120.6% and the precision expressed in RSD was less than 15.6%. This method was successfully applied to measure the concentrations of the 12 nucleotides, creatine phosphate and creatine in rat heart for the first time.
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Affiliation(s)
- Jun-mei Wang
- Department of Pharmacology and Toxicology, Tasly R&D Institute, Tianjin Tasly Group Co., Ltd, Tianjin 300410, China; Heilongjiang University of Traditional Chinese Medicine, Harbin 150040, China
| | - Yang Chu
- Department of Pharmacology and Toxicology, Tasly R&D Institute, Tianjin Tasly Group Co., Ltd, Tianjin 300410, China
| | - Wei Li
- Department of Pharmacology and Toxicology, Tasly R&D Institute, Tianjin Tasly Group Co., Ltd, Tianjin 300410, China.
| | - Xiang-yang Wang
- Department of Pharmacology and Toxicology, Tasly R&D Institute, Tianjin Tasly Group Co., Ltd, Tianjin 300410, China
| | - Jia-hua Guo
- Department of Pharmacology and Toxicology, Tasly R&D Institute, Tianjin Tasly Group Co., Ltd, Tianjin 300410, China
| | - Lu-lu Yan
- Department of Pharmacology and Toxicology, Tasly R&D Institute, Tianjin Tasly Group Co., Ltd, Tianjin 300410, China
| | - Xiao-hui Ma
- Department of Pharmacology and Toxicology, Tasly R&D Institute, Tianjin Tasly Group Co., Ltd, Tianjin 300410, China
| | - Ying-li Ma
- Heilongjiang University of Traditional Chinese Medicine, Harbin 150040, China
| | - Qi-hui Yin
- Department of Pharmacology and Toxicology, Tasly R&D Institute, Tianjin Tasly Group Co., Ltd, Tianjin 300410, China; Heilongjiang University of Traditional Chinese Medicine, Harbin 150040, China
| | - Chang-xiao Liu
- Tianjin State Key Laboratory of Pharmacokinetics and Pharmacodynamics, Tianjin Institute of Pharmaceutical Research, Tianjin 300193, China
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Abstract
The advancement of both LC and MS has contributed significantly to phospholipid analysis. Two major trends of developments have emerged in the past decade: application of dedicated online (or offline) LC–MS techniques including 2D and sophisticated chromatographic separations, and the development of so-called shotgun lipidomics represented by multidimensional MS-based techniques. However, neither of these techniques have been shown to be a universal solution for the increasing demand on the comprehensive information of lipid metabolomics in lipidomics studies. This is partially due to the intrinsic complexity of naturally occurring phospholipids in practice. It is evident that either chromatography or MS has to go multidimensional in order to fulfil this goal. This review focuses on recent developments of multidimensional MS, LC–MS and chromatographic approaches for lipidomics analysis. The perspectives and retrospectives of chromatography and MS in these aspects will be reviewed and discussed.
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Pesek JJ, Matyska MT, Hearn MTW, Boysen RI. Aqueous normal-phase retention of nucleotides on silica hydride columns. J Chromatogr A 2008; 1216:1140-6. [PMID: 19135674 DOI: 10.1016/j.chroma.2008.12.046] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Revised: 12/15/2008] [Accepted: 12/17/2008] [Indexed: 10/21/2022]
Abstract
The use of silica hydride-based stationary phases for the retention and analysis of nucleotides has been investigated. Both reversed-phase columns with a hydride surface underneath as well as those with an unmodified or a minimally modified hydride material were tested. With these systems, an aqueous normal-phase mode was used with high organic content mobile phases in combination with an additive to control pH for the retention of the hydrophilic nucleotides. Isocratic and gradient elution formats have been used to optimize separations for mixtures containing up to seven components. All conditions developed are suitable for methods that utilize mass spectrometry detection.
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Affiliation(s)
- Joseph J Pesek
- Department of Chemistry, San Jose State University, San Jose, CA 95112, USA.
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Klawitter J, Schmitz V, Klawitter J, Leibfritz D, Christians U. Development and validation of an assay for the quantification of 11 nucleotides using LC/LC-electrospray ionization-MS. Anal Biochem 2007; 365:230-9. [PMID: 17475198 DOI: 10.1016/j.ab.2007.03.018] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2006] [Revised: 01/09/2007] [Accepted: 03/17/2007] [Indexed: 11/22/2022]
Abstract
A unique quantitative high-performance liquid chromatography-mass spectrometry (HPLC-MS) method to investigate the energy state in cells and tissues was developed and validated using a chromatographic method designed to (i) separate and quantify more than 11 nucleotides without the use of phosphate buffer and (ii) minimize the potential ion suppression common to other nucleotide methods. Several commonly used extraction methods were compared based on absolute recoveries and reproducibilities. Perchloric acid (PCA) extraction yielded the highest recoveries (75-86%) and showed the best reproducibility (coefficient of variation=2.5-9.5%). Our assay, which included PCA extraction, online desalting, separation of the high-energy phosphates on a C18 reversed-phase column using a methanol/dibutylammonium formate gradient, and detection of negative ions in the single ion mode, met all predefined acceptance criteria for the quantification of AMP, ADP, ATP, CDP, CTP, FAD, GDP, GTP, UDP, and UTP. Detection limits ranged from 0.25 pmol on-column (FAD) to 4 pmol (NAD+). Assay development also included validation of tissue sample collection procedures. ATP/ADP concentrations and the resulting energy charge in kidney tissues are very sensitive to hypoxia, with significant decreases occurring within seconds. Avoidance of hypoxia during tissue retrieval is critical, and in vivo freeze clamping compares favorably with other tissue collection techniques.
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Affiliation(s)
- Jost Klawitter
- Clinical Research and Development, Department of Anesthesiology, University of Colorado at Denver and Health Sciences Center, Denver, CO 80262, USA.
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Han X, Gross RW. Shotgun lipidomics: electrospray ionization mass spectrometric analysis and quantitation of cellular lipidomes directly from crude extracts of biological samples. MASS SPECTROMETRY REVIEWS 2005; 24:367-412. [PMID: 15389848 DOI: 10.1002/mas.20023] [Citation(s) in RCA: 876] [Impact Index Per Article: 46.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Lipidomics, after genomics and proteomics, is a newly and rapidly expanding research field that studies cellular lipidomes and the organizational hierarchy of lipid and protein constituents mediating life processes. Lipidomics is greatly facilitated by recent advances in, and novel applications of, electrospray ionization mass spectrometry (ESI/MS). In this review, we will focus on the advances in ESI/MS, which have facilitated the development of shotgun lipidomics and the utility of intrasource separation as an enabling strategy for utilization of 2D mass spectrometry in shotgun lipidomics of biological samples. The principles and experimental details of the intrasource separation approach will be extensively discussed. Other ESI/MS approaches towards the quantitative analyses of global cellular lipidomes directly from crude lipid extracts of biological samples will also be reviewed and compared. Multiple examples of lipidomic analyses from crude lipid extracts employing these approaches will be given to show the power of ESI/MS techniques in lipidomics. Currently, modern society is plagued by the sequelae of lipid-related diseases. It is our hope that the integration of these advances in multiple disciplines will catalyze the development of lipidomics, and such development will lead to improvements in diagnostics and therapeutics, which will ultimately result in the extended longevity and an improved quality of life for humankind.
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Affiliation(s)
- Xianlin Han
- Division of Bioorganic Chemistry and Molecular Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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Martins EF, Miyasaka CK, Newsholme P, Curi R, Carpinelli AR. Changes of fatty acid composition in incubated rat pancreatic islets. DIABETES & METABOLISM 2004; 30:21-7. [PMID: 15029094 DOI: 10.1016/s1262-3636(07)70085-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The hypothesis that changes in fatty acId composition of pancreatic islets occur during incubation was investigated. METHODS The content and composition of fatty acIds (FA) from rat pancreatic islets and culture medium after incubation for 1 and 3 hours in the absence or in the presence of 5.6, 8.3, or 16.7 mM glucose were determined by HPLC analysis. RESULTS The FA content of pancreatic islets was reduced after 1 hour incubation in the absence of glucose. However, the total FA content was restored by incubating in the presence of 5.6 mM glucose and exceeded by incubating in the presence of 8.3 mM or 16.7 mM glucose. Saturated FA contributed a substantially greater proportion of the total FA increase in comparison to unsaturated FA, being palmitic and stearic acIds the most important. The total lipId content of pancreatic islets was not increased if the period of incubation in the presence of glucose was extended to 3 hours. A substantial amount of FA was found in the medium after 1 hour incubation in the absence of glucose: 141 ng per 80 islets for saturated and 75 ng per 80 islets for unsaturated. The release of FA from islets is increased in the presence of glucose. CONCLUSION The release of FA from islets is a novel finding and may be related to modulation of B-cell function.
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Affiliation(s)
- E F Martins
- Center of Biological Sciences and Health, University of Cruzeiro do Sul, São Paulo, SP, Brazil.
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Fujino T, Asaba H, Kang MJ, Ikeda Y, Sone H, Takada S, Kim DH, Ioka RX, Ono M, Tomoyori H, Okubo M, Murase T, Kamataki A, Yamamoto J, Magoori K, Takahashi S, Miyamoto Y, Oishi H, Nose M, Okazaki M, Usui S, Imaizumi K, Yanagisawa M, Sakai J, Yamamoto TT. Low-density lipoprotein receptor-related protein 5 (LRP5) is essential for normal cholesterol metabolism and glucose-induced insulin secretion. Proc Natl Acad Sci U S A 2003; 100:229-34. [PMID: 12509515 PMCID: PMC140935 DOI: 10.1073/pnas.0133792100] [Citation(s) in RCA: 299] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
A Wnt coreceptor low-density lipoprotein receptor-related protein 5 (LRP5) plays an essential role in bone accrual and eye development. Here, we show that LRP5 is also required for normal cholesterol and glucose metabolism. The production of mice lacking LRP5 revealed that LRP5 deficiency led to increased plasma cholesterol levels in mice fed a high-fat diet, because of the decreased hepatic clearance of chylomicron remnants. In addition, when fed a normal diet, LRP5-deficient mice showed a markedly impaired glucose tolerance. The LRP5-deficient islets had a marked reduction in the levels of intracellular ATP and Ca(2+) in response to glucose, and thereby glucose-induced insulin secretion was decreased. The intracellular inositol 1,4,5-trisphosphate (IP3) production in response to glucose was also reduced in LRP5-- islets. Real-time PCR analysis revealed a marked reduction of various transcripts for genes involved in glucose sensing in LRP5-- islets. Furthermore, exposure of LRP5++ islets to Wnt-3a and Wnt-5a stimulates glucose-induced insulin secretion and this stimulation was blocked by the addition of a soluble form of Wnt receptor, secreted Frizzled-related protein-1. In contrast, LRP5-deficient islets lacked the Wnt-3a-stimulated insulin secretion. These data suggest that WntLRP5 signaling contributes to the glucose-induced insulin secretion in the islets.
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Affiliation(s)
- Takahiro Fujino
- Gene Research Center and Division of Nephrology, Endocrinology, and Vascular Medicine, Department of Medicine, Tohoku University, Sendai 980-8574, Japan
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Martelli AM, Bortul R, Tabellini G, Aluigi M, Peruzzi D, Bareggi R, Narducci P, Cocco L. Re-examination of the mechanisms regulating nuclear inositol lipid metabolism. FEBS Lett 2001; 505:1-6. [PMID: 11557031 DOI: 10.1016/s0014-5793(01)02752-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Although inositol lipids constitute only a very minor proportion of total cellular lipids, they have received immense attention by scientists since it was discovered that they play key roles in a wide range of important cellular processes. In the late 1980s, it was suggested that these lipids are also present within the cell nucleus. Albeit the early reports about the intranuclear localization of phosphoinositides were met by skepticism and disbelief, compelling evidence has subsequently been accumulated convincingly showing that a phosphoinositide cycle is present at the nuclear level and may be activated in response to stimuli that do not activate the inositol lipid metabolism localized at the plasma membrane. Very recently, intriguing new data have highlighted that some of the mechanisms regulating nuclear inositol lipid metabolism differ in a substantial way from those operating at the cell periphery. Here, we provide an overview of recent findings regarding the regulation of both nuclear phosphatidylinositol 3-kinase and phosphoinositide-specific phospholipase C-beta1.
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Affiliation(s)
- A M Martelli
- Dipartmento di Scienze Anatomiche Umane e Fisiopatologia dell'Apparto Locomotore, Sezione di Anatomia, Università di Bologna, Italy.
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Hsu FF, Turk J. Characterization of phosphatidylinositol, phosphatidylinositol-4-phosphate, and phosphatidylinositol-4,5-bisphosphate by electrospray ionization tandem mass spectrometry: a mechanistic study. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2000; 11:986-999. [PMID: 11073262 DOI: 10.1016/s1044-0305(00)00172-0] [Citation(s) in RCA: 176] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Structural characterization of phosphatidylinositol (PI), phosphatidylinositol-4-phosphate (PI-4P), and phosphatidylinositol-4,5-bisphosphate (PI-4,5-P2) by collisionally activated dissociation (CAD) tandem mass spectrometry with electrospray ionization is described. In negative ion mode, the major fragmentation pathways under low energy CAD for PI arise from neutral loss of free fatty acid substituents ([M - H - RxCO2H]-) and neutral loss of the corresponding ketenes ([M - H - R'xCH=C=O]-), followed by consecutive loss of the inositol head group. The intensities of the ions arising from neutral loss of the sn-2 substituent as a free fatty acid ([M - H - R2CO2H]-) or as a ketene ([M - H - R'2CH=C=O] ) are greater than those of ions reflecting corresponding losses of the sn-1 substutient. This is consistent with our recent finding that ions reflecting those losses arise from charge-driven processes that occur preferentially at the sn-2 position. These features permit assignment of the position of the fatty acid substituents on the glycerol backbone. Nucleophilic attack of the anionic phosphate onto the C-1 or the C-2 of the glycerol to which the fatty acids attached expels sn-1 (R1CO2-) or sn-2 (R2CO2-) carboxylate anion, respectively. This pathway is sterically more favorable at sn-2 than at sn-1. However, further dissociations of [M - H - RxCO2H - inositol] , [M - H - RxCO2H]-, and [M - H - RxCH=C=O]- precursor ions also yield RxCO2- ions, whose abundance are affected by the collision energy applied. Therefore, relative intensities of the RxCO2- ions in the spectrum do not reflect their positions on the glycerol backbone and determination of their regiospecificities based on their ion intensities is not reliable. The spectra also contain specific ions at m/z 315, 279, 259, 241, and 223, reflecting the inositol head group. The last three ions are also observed in the tandem spectra of the [M - H]- ions of phosphatidylinositol monophosphate (PI-P) and phosphatidylinositol bisphosphate (PI-P2), in addition to the ions at m/z 321 and 303, reflecting the doubly phosphorylated inositol ions. The PI-P2 also contains unique ions at m/z 401 and 383 that reflect the triply phosphorylated inositol ions. The [M - H]- ions of PI-P and PI-P2 undergo fragmentation pathways similar to that of PI upon CAD. However, the doubly charged ([M - 2H]2-) molecular ions undergo fragmentation pathways that are typical of the [M - H]- ions of glycerophosphoethanolamine, which are basic. These results suggest that the further deprotonated gaseous [M - 2H]2 ions of PI-P and PI-P2 are basic precursors.
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Affiliation(s)
- F F Hsu
- Department of Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA.
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Abstract
Fructose-2,6-bisphosphate is an important intracellular biofactor in the control of carbohydrate metabolic fluxes in eukaryotes. It is generated from ATP and fructose-6-phosphate by 6-phosphofructo-2-kinase and degraded to fructose-6-phosphate and phosphate ion by fructose-2,6-bisphosphatase. In most organisms these enzymatic activities are contained in a single polypeptide. The reciprocal modulation of the kinase and bisphosphatase activities by post-translational modifications places the level of the biofactor under the control of extra-cellular signals. In general, these signals are generated in response to changing nutritional states, therefore, fructose-2,6-bisphosphate plays a role in the adaptation of organisms, and the tissues within them, to changes in environmental and metabolic states. Although the specific mechanism of fructose-2,6-bisphosphate action varies between species and between tissues, most involve the allosteric activation of 6-phosphofructo-1-kinase and inhibition of fructose-1,6-bisphosphatase. These highly conserved enzymes regulate the fructose-6-phosphate/fructose-1,6-bisphosphate cycle, and thereby, determine the carbon flux. It is by reciprocal modulation of these activities that fructose-2,6-bisphosphate plays a fundamental role in eukaryotic carbohydrate metabolism.
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Affiliation(s)
- D A Okar
- University of Minnesota, Medical School, Department of Biochemistry, Molecular Biology, and Biophysics, Minneapolis 55455, USA
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