1
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Karalis T, Poulogiannis G. The Emerging Role of LPA as an Oncometabolite. Cells 2024; 13:629. [PMID: 38607068 PMCID: PMC11011573 DOI: 10.3390/cells13070629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/25/2024] [Accepted: 04/01/2024] [Indexed: 04/13/2024] Open
Abstract
Lysophosphatidic acid (LPA) is a phospholipid that displays potent signalling activities that are regulated in both an autocrine and paracrine manner. It can be found both extra- and intracellularly, where it interacts with different receptors to activate signalling pathways that regulate a plethora of cellular processes, including mitosis, proliferation and migration. LPA metabolism is complex, and its biosynthesis and catabolism are under tight control to ensure proper LPA levels in the body. In cancer patient specimens, LPA levels are frequently higher compared to those of healthy individuals and often correlate with poor responses and more aggressive disease. Accordingly, LPA, through promoting cancer cell migration and invasion, enhances the metastasis and dissemination of tumour cells. In this review, we summarise the role of LPA in the regulation of critical aspects of tumour biology and further discuss the available pre-clinical and clinical evidence regarding the feasibility and efficacy of targeting LPA metabolism for effective anticancer therapy.
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Affiliation(s)
| | - George Poulogiannis
- Signalling and Cancer Metabolism Laboratory, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK;
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2
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Öling S, Struck E, Noreen-Thorsen M, Zwahlen M, von Feilitzen K, Odeberg J, Pontén F, Lindskog C, Uhlén M, Dusart P, Butler LM. A human stomach cell type transcriptome atlas. BMC Biol 2024; 22:36. [PMID: 38355543 PMCID: PMC10865703 DOI: 10.1186/s12915-024-01812-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 01/02/2024] [Indexed: 02/16/2024] Open
Abstract
BACKGROUND The identification of cell type-specific genes and their modification under different conditions is central to our understanding of human health and disease. The stomach, a hollow organ in the upper gastrointestinal tract, provides an acidic environment that contributes to microbial defence and facilitates the activity of secreted digestive enzymes to process food and nutrients into chyme. In contrast to other sections of the gastrointestinal tract, detailed descriptions of cell type gene enrichment profiles in the stomach are absent from the major single-cell sequencing-based atlases. RESULTS Here, we use an integrative correlation analysis method to predict human stomach cell type transcriptome signatures using unfractionated stomach RNAseq data from 359 individuals. We profile parietal, chief, gastric mucous, gastric enteroendocrine, mitotic, endothelial, fibroblast, macrophage, neutrophil, T-cell, and plasma cells, identifying over 1600 cell type-enriched genes. CONCLUSIONS We uncover the cell type expression profile of several non-coding genes strongly associated with the progression of gastric cancer and, using a sex-based subset analysis, uncover a panel of male-only chief cell-enriched genes. This study provides a roadmap to further understand human stomach biology.
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Affiliation(s)
- S Öling
- Department of Clinical Medicine, Translational Vascular Research, The Arctic University of Norway, 9019, Tromsø, Norway
| | - E Struck
- Department of Clinical Medicine, Translational Vascular Research, The Arctic University of Norway, 9019, Tromsø, Norway
| | - M Noreen-Thorsen
- Department of Clinical Medicine, Translational Vascular Research, The Arctic University of Norway, 9019, Tromsø, Norway
| | - M Zwahlen
- Science for Life Laboratory, Department of Protein Science, Royal Institute of Technology (KTH), 171 21, Stockholm, Sweden
| | - K von Feilitzen
- Science for Life Laboratory, Department of Protein Science, Royal Institute of Technology (KTH), 171 21, Stockholm, Sweden
| | - J Odeberg
- Department of Clinical Medicine, Translational Vascular Research, The Arctic University of Norway, 9019, Tromsø, Norway
- Science for Life Laboratory, Department of Protein Science, Royal Institute of Technology (KTH), 171 21, Stockholm, Sweden
- The University Hospital of North Norway (UNN), 9019, Tromsø, Norway
- Department of Haematology, Coagulation Unit, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - F Pontén
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, 752 37, Uppsala, Sweden
| | - C Lindskog
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, 752 37, Uppsala, Sweden
| | - M Uhlén
- Science for Life Laboratory, Department of Protein Science, Royal Institute of Technology (KTH), 171 21, Stockholm, Sweden
| | - P Dusart
- Science for Life Laboratory, Department of Protein Science, Royal Institute of Technology (KTH), 171 21, Stockholm, Sweden
- Clinical Chemistry and Blood Coagulation Research, Department of Molecular Medicine and Surgery, Karolinska Institute, 171 76, Stockholm, Sweden
- Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - L M Butler
- Department of Clinical Medicine, Translational Vascular Research, The Arctic University of Norway, 9019, Tromsø, Norway.
- Science for Life Laboratory, Department of Protein Science, Royal Institute of Technology (KTH), 171 21, Stockholm, Sweden.
- Clinical Chemistry and Blood Coagulation Research, Department of Molecular Medicine and Surgery, Karolinska Institute, 171 76, Stockholm, Sweden.
- Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, 171 76, Stockholm, Sweden.
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3
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Diet evolution of carnivorous and herbivorous mammals in Laurasiatheria. BMC Ecol Evol 2022; 22:82. [PMID: 35729512 PMCID: PMC9210794 DOI: 10.1186/s12862-022-02033-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 12/09/2021] [Indexed: 11/15/2022] Open
Abstract
Background Laurasiatheria contains taxa with diverse diets, while the molecular basis and evolutionary history underlying their dietary diversification are less clear. Results In this study, we used the recently developed molecular phyloecological approach to examine the adaptive evolution of digestive system-related genes across both carnivorous and herbivorous mammals within Laurasiatheria. Our results show an intensified selection of fat and/or protein utilization across all examined carnivorous lineages, which is consistent with their high-protein and high-fat diets. Intriguingly, for herbivorous lineages (ungulates), which have a high-carbohydrate diet, they show a similar selection pattern as that of carnivorous lineages. Our results suggest that for the ungulates, which have a specialized digestive system, the selection intensity of their digestive system-related genes does not necessarily reflect loads of the nutrient components in their diets but appears to be positively related to the loads of the nutrient components that are capable of being directly utilized by the herbivores themselves. Based on these findings, we reconstructed the dietary evolution within Laurasiatheria, and our results reveal the dominant carnivory during the early diversification of Laurasiatheria. In particular, our results suggest that the ancestral bats and the common ancestor of ruminants and cetaceans may be carnivorous as well. We also found evidence of the convergent evolution of one fat utilization-related gene, APOB, across carnivorous taxa. Conclusions Our molecular phyloecological results suggest that digestive system-related genes can be used to determine the molecular basis of diet differentiations and to reconstruct ancestral diets. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-022-02033-6.
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Kono M, Hoachlander-Hobby LE, Majumder S, Schwartz R, Byrnes C, Zhu H, Proia RL. Identification of two lipid phosphatases that regulate sphingosine-1-phosphate cellular uptake and recycling. J Lipid Res 2022; 63:100225. [PMID: 35568252 PMCID: PMC9213771 DOI: 10.1016/j.jlr.2022.100225] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 05/06/2022] [Accepted: 05/07/2022] [Indexed: 12/29/2022] Open
Abstract
Sphingosine-1-phosphate (S1P) is a sphingolipid metabolite that serves as a potent extracellular signaling molecule. Metabolic regulation of extracellular S1P levels impacts key cellular activities through altered S1P receptor signaling. Although the pathway through which S1P is degraded within the cell and thereby eliminated from reuse has been previously described, the mechanism used for S1P cellular uptake and the subsequent recycling of its sphingoid base into the sphingolipid synthesis pathway is not completely understood. To identify the genes within this S1P uptake and recycling pathway, we performed a genome-wide CRISPR/Cas9 KO screen using a positive-selection scheme with Shiga toxin, which binds a cell-surface glycosphingolipid receptor, globotriaosylceramide (Gb3), and causes lethality upon internalization. The screen was performed in HeLa cells with their sphingolipid de novo pathway disabled so that Gb3 cell-surface expression was dependent on salvage of the sphingoid base of S1P taken up from the medium. The screen identified a suite of genes necessary for S1P uptake and the recycling of its sphingoid base to synthesize Gb3, including two lipid phosphatases, PLPP3 (phospholipid phosphatase 3) and SGPP1 (S1P phosphatase 1). The results delineate a pathway in which plasma membrane–bound PLPP3 dephosphorylates extracellular S1P to sphingosine, which then enters cells and is rephosphorylated to S1P by the sphingosine kinases. This rephosphorylation step is important to regenerate intracellular S1P as a branch-point substrate that can be routed either for dephosphorylation to salvage sphingosine for recycling into complex sphingolipid synthesis or for degradation to remove it from the sphingolipid synthesis pathway.
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Affiliation(s)
- Mari Kono
- Genetics of Development and Disease Section, Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda MD, USA
| | - Lila E Hoachlander-Hobby
- Genetics of Development and Disease Section, Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda MD, USA
| | - Saurav Majumder
- Genetics of Development and Disease Section, Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda MD, USA
| | - Ronit Schwartz
- Genetics of Development and Disease Section, Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda MD, USA
| | - Colleen Byrnes
- Genetics of Development and Disease Section, Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda MD, USA
| | - Hongling Zhu
- Genetics of Development and Disease Section, Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda MD, USA
| | - Richard L Proia
- Genetics of Development and Disease Section, Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda MD, USA
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Su W, Raza A, Gao A, Zeng L, Lv Y, Ding X, Cheng Y, Zou X. Plant lipid phosphate phosphatases: current advances and future outlooks. Crit Rev Biotechnol 2022; 43:384-392. [PMID: 35430946 DOI: 10.1080/07388551.2022.2032588] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Lipids are widely distributed in various tissues of an organism, mainly in plant storage organs (e.g., fruits, seeds, etc.). Lipids are vital biological substances that are involved in: signal transduction, membrane biogenesis, energy storage, and the formation of transmembrane fat-soluble substances. Some lipids and related lipid derivatives could be changed in their: content, location, or physiological activity by the external environment, such as biotic or abiotic stresses. Lipid phosphate phosphatases (LPPs) play important roles in regulating intermediary lipid metabolism and cellular signal response. LPPs can dephosphorylate lipid phosphates containing phosphate monolipid bonds such as: phosphatidic acid, lysophosphatidic acid (LPA), and diacylglycerol pyrophosphate, etc. These processes can change the contents of some important lipid signal mediation such as diacylglycerol and LPA, affecting lipid signal transmission. Here, we summarize the research progress of LPPs in plants, emphasizing the structural and biochemical characteristics of LPPs and their role in spatio-temporal regulation. In the future, more in-depth studies are required to boost our understanding of the key role of plant LPPs and lipid metabolism in: signal regulation, stress tolerance pathway, and plant growth and development.
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Affiliation(s)
- Wei Su
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Wuhan, China
| | - Ali Raza
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Wuhan, China
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Center of Legume Crop Genetics and Systems Biology/College of Agriculture, Oil Crops Research Institute, Fujian Agriculture and Forestry University (FAFU), Fuzhou, China
| | - Ang Gao
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Wuhan, China
| | - Liu Zeng
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Wuhan, China
| | - Yan Lv
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Wuhan, China
| | - Xiaoyu Ding
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Wuhan, China
| | - Yong Cheng
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Wuhan, China
| | - Xiling Zou
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Wuhan, China
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Trombetta D, Sparaneo A, Fabrizio FP, Di Micco CM, Rossi A, Muscarella LA. NRG1 and NRG2 fusions in non-small cell lung cancer (NSCLC): seven years between lights and shadows. Expert Opin Ther Targets 2021; 25:865-875. [PMID: 34706602 DOI: 10.1080/14728222.2021.1999927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Fusions in neuregulin 1 (NRG1) and neuregulin 2 (NRG2) genes are molecular features of non-small cell lung cancer (NSCLC). These rearrangements enhance ectopic expression of the NRG/ErbB receptor-ligand and induce the triggering of downstream pathways. Evidence suggests the involvement of the NRG1/ErbB3 axis deregulation in the progression and treatment resistance of NSCLC cancer (NSCLC) and that NRG1 fusions are prognostic/predictive markers for targeted therapy. AREAS COVERED Biological and prognostic/predictive value of NRG1 and NRG2 fusions in NSCLC and their related cellular pathways are described and discussed. Publications in English language, peer-reviewed, high-quality international journals were identified on PubMed, as well as scientific official sites were used to update the international clinical trials progress. EXPERT OPINION NRG1 and NRG2 fusions should be considered as novel markers for biological therapy targeting ErbB2/ErbB3. There is evidence for the involvement of the NRG1/ErbB3 axis deregulation in cancer stem cell phenotype, tumor progression, and resistance to NSCLC therapy. Neuregulin fusions are very complex, hence many question marks must be tackled before translating these molecular lesions into clinical practice. Biology, and aggressiveness of the NRG1 and NRG2 fusions warrant further investigations.
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Affiliation(s)
- Domenico Trombetta
- Laboratory of Oncology, Fondazione Irccs Casa Sollievo Della Sofferenza Hospital, San Giovanni Rotondo, Italy
| | - Angelo Sparaneo
- Laboratory of Oncology, Fondazione Irccs Casa Sollievo Della Sofferenza Hospital, San Giovanni Rotondo, Italy
| | - Federico Pio Fabrizio
- Laboratory of Oncology, Fondazione Irccs Casa Sollievo Della Sofferenza Hospital, San Giovanni Rotondo, Italy
| | - Concetta Martina Di Micco
- Unit of Oncology, Fondazione Irccs Casa Sollievo Della Sofferenza Hospital, San Giovanni Rotondo, Italy
| | - Antonio Rossi
- Unit of Oncology, Fondazione Irccs Casa Sollievo Della Sofferenza Hospital, San Giovanni Rotondo, Italy
| | - Lucia Anna Muscarella
- Laboratory of Oncology, Fondazione Irccs Casa Sollievo Della Sofferenza Hospital, San Giovanni Rotondo, Italy
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Ou SHI, Xiu J, Nagasaka M, Xia B, Zhang SS, Zhang Q, Swensen JJ, Spetzler D, Korn WM, Zhu VW, Liu SV. Identification of Novel CDH1-NRG2α and F11R-NRG2α Fusions in NSCLC Plus Additional Novel NRG2α Fusions in Other Solid Tumors by Whole Transcriptome Sequencing. JTO Clin Res Rep 2021; 2:100132. [PMID: 34589990 PMCID: PMC8474258 DOI: 10.1016/j.jtocrr.2020.100132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Introduction A novel CD74-NRG2α fusion has recently been identified in NSCLC. We surveyed a large tumor database comprehensively profiled by whole transcriptome sequencing to investigate the incidence and distribution of NRG2 fusions among various solid tumors. Methods Tumor samples submitted for clinical molecular profiling at Caris Life Sciences (Phoenix, AZ) that underwent whole transcriptome sequencing (NovaSeq [Illumina, San Diego, CA]) were retrospectively analyzed for NRG2 fusion events. All NRG2 fusions with sufficient reads (> three junctional reads spanning ≥ seven nucleotides) were identified for manual review, characterization of fusion class, intact functional domains, EGF-like domain isoforms, breakpoints, frame retention, and co-occurring alterations by next-generation sequencing (NextSeq [Illumina, San Diego, CA], 592 genes). Results Seven inframe functional (containing the intact EGF-like domain) NRG2α fusions were identified, namely, the following: (1) NSCLC (two of 9600, 0.02%: CDH1-NRG2α [C11, N2], F11R-NRG2α [F1, N4]); (2) endometrial (two of 3060, 0.065%: CPM-NRG2α [C2, N2], OPA3-NRG2α [O1, N2]); (3) ovarian (one of 5030, 0.02%: SPON1-NRG2α [S6, N2]); (4) prostate (one of 1600, 0.063%: PLPP1-NRG2α [P1, N2]); and (5) carcinoma of unknown origin (one of 1400, 0.07%: CYSTM1-NRG2α [C2, N2]). No NRG2β fusions were identified. Both NSCLC samples contained the reciprocal NRG2 fusions (NRG2-CDH1, NRG2-F11R). Almost all inframe NRG2α fusions have no (N = 6, 85.7%) or low (N = 1, 14.3%) programmed death-ligand 1 expression. No additional known driver mutations were identified in these seven NRG2α fusion-positive tumor samples. Conclusions Similar to NRG1 fusions, NRG2α fusions are recurrent and rare ligand-fusions in NSCLC and other multiple tumor types, especially gynecologic malignancies.
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Affiliation(s)
- Sai-Hong Ignatius Ou
- Department of Medicine, University of California Irvine School of Medicine, Orange, California.,Chao Family Comprehensive Cancer Center, Orange, California
| | | | - Misako Nagasaka
- Department of Medical Oncology, Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan.,Division of Neurology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki, Japan
| | - Bing Xia
- Division of Oncology, Department of Medicine, USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California
| | - Shannon S Zhang
- Department of Medicine, University of California Irvine School of Medicine, Orange, California
| | | | | | | | | | - Viola W Zhu
- Department of Medicine, University of California Irvine School of Medicine, Orange, California.,Chao Family Comprehensive Cancer Center, Orange, California
| | - Stephen V Liu
- Division of Hematology-Oncology, Department of Medicine, Georgetown Lombardi Comprehensive Cancer Center, Georgetown University School of Medicine, Washington, District of Columbia
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8
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Tang X, Brindley DN. Lipid Phosphate Phosphatases and Cancer. Biomolecules 2020; 10:biom10091263. [PMID: 32887262 PMCID: PMC7564803 DOI: 10.3390/biom10091263] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 08/28/2020] [Accepted: 08/30/2020] [Indexed: 12/22/2022] Open
Abstract
Lipid phosphate phosphatases (LPPs) are a group of three enzymes (LPP1–3) that belong to a phospholipid phosphatase (PLPP) family. The LPPs dephosphorylate a wide spectrum of bioactive lipid phosphates, among which lysophosphatidate (LPA) and sphingosine 1-phosphate (S1P) are two important extracellular signaling molecules. The LPPs are integral membrane proteins, which are localized on plasma membranes and intracellular membranes, including the endoplasmic reticulum and Golgi network. LPPs regulate signaling transduction in cancer cells and demonstrate different effects in cancer progression through the breakdown of extracellular LPA and S1P and other intracellular substrates. This review is intended to summarize an up-to-date understanding about the functions of LPPs in cancers.
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Affiliation(s)
- Xiaoyun Tang
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2S2, Canada;
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - David N. Brindley
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2S2, Canada;
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB T6G 2E1, Canada
- Correspondence:
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Laskowski D, Andersson G, Humblot P, Sirard MA, Sjunnesson Y, Ferreira CR, Pirro V, Båge R. Lipid profile of bovine blastocysts exposed to insulin during in vitro oocyte maturation. Reprod Fertil Dev 2019; 30:1253-1266. [PMID: 29655403 DOI: 10.1071/rd17248] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 03/01/2018] [Indexed: 01/22/2023] Open
Abstract
Insulin is a key hormone with important functions in energy metabolism and is involved in the regulation of reproduction. Hyperinsulinaemia is known to impair fertility (for example, in obese mothers); therefore, we aimed to investigate the impact of elevated insulin concentrations during the sensitive period of oocyte maturation on gene expression and lipid profiles of the bovine Day-8 embryo. Two different insulin concentrations were used during in vitro oocyte maturation (INS10=10µgmL-1 and INS0.1=0.1µgmL-1) in order to observe possible dose-dependent effects or thresholds for hyperinsulinaemia in vitro. By investigating gene expression patterns by an mRNA microarray in combination with lipid profile analysis by desorption electrospray ionisation-mass spectrometry (DESI-MS) of embryos derived from insulin-treated oocytes, we gained further insights regarding molecular responses of embryos to insulin provocation during the first days of development. Lipid metabolism appeared to be influenced on multiple levels according to gene expression results but the profiles collected in positive-ion mode by DESI-MS (showing mostly ubiquinone, cholesteryl esters and triacylglycerols) did not differ significantly from controls. There are parallels in follicular development of ruminants and humans that make this bovine model relevant for comparative research on early human embryonic development during hyperinsulinaemia.
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Affiliation(s)
- Denise Laskowski
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, PO Box 7054, SE-750 07 Uppsala, Sweden
| | - Göran Andersson
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, PO Box 7023, SE-750 07 Uppsala, Sweden
| | - Patrice Humblot
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, PO Box 7054, SE-750 07 Uppsala, Sweden
| | - Marc-André Sirard
- Departement des Sciences Animales, Centre de Recherche en Biologie de la Reproduction, Pavillon Des Services, Local 2732, University Laval, Québec G1V 0A6, Canada
| | - Ylva Sjunnesson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, PO Box 7054, SE-750 07 Uppsala, Sweden
| | - Christina R Ferreira
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907-2084, USA
| | - Valentina Pirro
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907-2084, USA
| | - Renée Båge
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, PO Box 7054, SE-750 07 Uppsala, Sweden
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10
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Weber K, Casali C, Gaveglio V, Pasquaré S, Morel Gómez E, Parra L, Erjavec L, Perazzo C, Fernández Tome MC. TAG synthesis and storage under osmotic stress. A requirement for preserving membrane homeostasis in renal cells. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:1108-1120. [DOI: 10.1016/j.bbalip.2018.06.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 05/11/2018] [Accepted: 06/12/2018] [Indexed: 12/14/2022]
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11
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Busnelli M, Manzini S, Parolini C, Escalante-Alcalde D, Chiesa G. Lipid phosphate phosphatase 3 in vascular pathophysiology. Atherosclerosis 2018. [DOI: 10.1016/j.atherosclerosis.2018.02.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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12
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Proteomic Identification of Heat Shock-Induced Danger Signals in a Melanoma Cell Lysate Used in Dendritic Cell-Based Cancer Immunotherapy. J Immunol Res 2018; 2018:3982942. [PMID: 29744371 PMCID: PMC5878886 DOI: 10.1155/2018/3982942] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 11/28/2017] [Accepted: 12/11/2017] [Indexed: 12/17/2022] Open
Abstract
Autologous dendritic cells (DCs) loaded with cancer cell-derived lysates have become a promising tool in cancer immunotherapy. During the last decade, we demonstrated that vaccination of advanced melanoma patients with autologous tumor antigen presenting cells (TAPCells) loaded with an allogeneic heat shock- (HS-) conditioned melanoma cell-derived lysate (called TRIMEL) is able to induce an antitumor immune response associated with a prolonged patient survival. TRIMEL provides not only a broad spectrum of potential melanoma-associated antigens but also danger signals that are crucial in the induction of a committed mature DC phenotype. However, potential changes induced by heat conditioning on the proteome of TRIMEL are still unknown. The identification of newly or differentially expressed proteins under defined stress conditions is relevant for understanding the lysate immunogenicity. Here, we characterized the proteomic profile of TRIMEL in response to HS treatment. A quantitative label-free proteome analysis of over 2800 proteins was performed, with 91 proteins that were found to be regulated by HS treatment: 18 proteins were overexpressed and 73 underexpressed. Additionally, 32 proteins were only identified in the HS-treated TRIMEL and 26 in non HS-conditioned samples. One protein from the overexpressed group and two proteins from the HS-exclusive group were previously described as potential damage-associated molecular patterns (DAMPs). Some of the HS-induced proteins, such as haptoglobin, could be also considered as DAMPs and candidates for further immunological analysis in the establishment of new putative danger signals with immunostimulatory functions.
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Xu Y, Xiao YJ, Baudhuin LM, Schwartz BM. The Role and Clinical Applications of Bioactive Lysolipids in Ovarian Cancer. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/107155760100800101] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Yan Xu
- Department of Cancer Biology Lerner Research Institute and the Department of Gynecology and Obstetrics Cleveland Clinic Foundation; Department of Chemistry, Cleveland State University, Cleveland, Ohio; Department of Cancer Biology, Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, OH 44195
| | | | | | - Benjamin M. Schwartz
- Department of Cancer Biology Lerner Research Institute and the Department of Gynecology and Obstetrics Cleveland Clinic Foundation; Department of Chemistry, Cleveland State University, Cleveland, Ohio
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Bullen HE, Soldati-Favre D. A central role for phosphatidic acid as a lipid mediator of regulated exocytosis in apicomplexa. FEBS Lett 2016; 590:2469-81. [PMID: 27403735 DOI: 10.1002/1873-3468.12296] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 07/10/2016] [Accepted: 07/11/2016] [Indexed: 11/08/2022]
Abstract
Lipids are commonly known for the structural roles they play, however, the specific contribution of different lipid classes to wide-ranging signalling pathways is progressively being unravelled. Signalling lipids and their associated effector proteins are emerging as significant contributors to a vast array of effector functions within cells, including essential processes such as membrane fusion and vesicle exocytosis. Many phospholipids have signalling capacity, however, this review will focus on phosphatidic acid (PA) and the enzymes implicated in its production from diacylglycerol (DAG) and phosphatidylcholine (PC): DGK and PLD respectively. PA is a negatively charged, cone-shaped lipid identified as a key mediator in specific membrane fusion and vesicle exocytosis events in a variety of mammalian cells, and has recently been implicated in specialised secretory organelle exocytosis in apicomplexan parasites. This review summarises the recent work implicating a role for PA regulation in exocytosis in various cell types. We will discuss how these signalling events are linked to pathogenesis in the phylum Apicomplexa.
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Guo A, Cai J, Luo X, Zhang S, Hou J, Li H, Cai X. Cloning and characterization of three Eimeria tenella lipid phosphate phosphatases. PLoS One 2015; 10:e0122736. [PMID: 25861032 PMCID: PMC4393304 DOI: 10.1371/journal.pone.0122736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 02/12/2015] [Indexed: 11/19/2022] Open
Abstract
Although lipid phosphate phosphatases (LPPs) play an important role in cellular signaling in addition to lipid biosynthesis, little is thus far known about parasite LPPs. In this study, we characterized three Eimeria tenella cDNA clones encoding LPP named EtLPP1, EtLPP2 and EtLPP3. Key structural features previously described in LPPs, including the three conserved domains proposed as catalytic sites, a single conserved N-glycosylation site, and putative transmembrane domains were discovered in the three resulting EtLPP amino acid sequences. Expression of His6-tagged EtLPP1, -2, and -3 in HEK293 cells produced immunoreactive proteins with variable molecular sizes, suggesting the presence of multiple forms of each of the three EtLPPs. The two faster-migrating protein bands below each of the three EtLPP proteins were found to be very similar to the porcine 35-kDa LPP enzyme in their molecular size and the extent of their N-glycosylation, suggesting that the three EtLPPs are partially N-glycosylated. Kinetic analyses of the activity of the three enzymes against PA, LPA, C1P and S1P showed that Km values for each of the substrates were (in μM) 284, 46, 28, and 22 for EtLPP1; 369, 179, 237, and 52 for EtLPP2; and 355, 83, and 260 for EtLPP3. However, EtLPP3 showed negligible activity on S1P. These results confirmed that the three EtLPPs have broad substrate specificity. The results also indicated that despite structural similarities, the three EtLPPs may play distinct functions through their different models of substrate preference. Furthermore, particularly high expression levels of the three EtLPP genes were detected in the sporozoite stage of the E. tenella life cycle (p<0.001), suggesting that their encoded proteins might play an important biological function in the sporozoite stage.
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Affiliation(s)
- Aijiang Guo
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease, Yangzhou, Jiangsu, China
- * E-mail:
| | - Jianping Cai
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Xuenong Luo
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease, Yangzhou, Jiangsu, China
| | - Shaohua Zhang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Junling Hou
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Hui Li
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
| | - Xuepeng Cai
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
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Tang X, Benesch MGK, Brindley DN. Lipid phosphate phosphatases and their roles in mammalian physiology and pathology. J Lipid Res 2015; 56:2048-60. [PMID: 25814022 DOI: 10.1194/jlr.r058362] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Indexed: 12/20/2022] Open
Abstract
Lipid phosphate phosphatases (LPPs) are a group of enzymes that belong to a phosphatase/phosphotransferase family. Mammalian LPPs consist of three isoforms: LPP1, LPP2, and LPP3. They share highly conserved catalytic domains and catalyze the dephosphorylation of a variety of lipid phosphates, including phosphatidate, lysophosphatidate (LPA), sphingosine 1-phosphate (S1P), ceramide 1-phosphate, and diacylglycerol pyrophosphate. LPPs are integral membrane proteins, which are localized on plasma membranes with the active site on the outer leaflet. This enables the LPPs to degrade extracellular LPA and S1P, thereby attenuating their effects on the activation of surface receptors. LPP3 also exhibits noncatalytic effects at the cell surface. LPP expression on internal membranes, such as endoplasmic reticulum and Golgi, facilitates the metabolism of internal lipid phosphates, presumably on the luminal surface of these organelles. This action probably explains the signaling effects of the LPPs, which occur downstream of receptor activation. The three isoforms of LPPs show distinct and nonredundant effects in several physiological and pathological processes including embryo development, vascular function, and tumor progression. This review is intended to present an up-to-date understanding of the physiological and pathological consequences of changing the activities of the different LPPs, especially in relation to cell signaling by LPA and S1P.
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Affiliation(s)
- Xiaoyun Tang
- Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta, T6G 2S2, Canada
| | - Matthew G K Benesch
- Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta, T6G 2S2, Canada
| | - David N Brindley
- Signal Transduction Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta, T6G 2S2, Canada
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Villasuso AL, Di Palma MA, Aveldaño M, Pasquaré SJ, Racagni G, Giusto NM, Machado EE. Differences in phosphatidic acid signalling and metabolism between ABA and GA treatments of barley aleurone cells. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2013; 65:1-8. [PMID: 23416490 DOI: 10.1016/j.plaphy.2013.01.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Accepted: 01/07/2013] [Indexed: 06/01/2023]
Abstract
Phosphatidic acid (PA) is the common lipid product in abscisic acid (ABA) and gibberellic acid (GA) response. In this work we investigated the lipid metabolism in response to both hormones. We could detect an in vivo phospholipase D activity (PLD, EC 3.1.4.4). This PLD produced [(32)P]PA (phosphatidic acid) rapidly (minutes) in the presence of ABA, confirming PA involvement in signal transduction, and transiently, indicating rapid PA removal after generation. The presence of PA removal by phosphatidate phosphatase 1 and 2 isoforms (E.C. 3.1.3.4) was verified in isolated aleurone membranes in vitro, the former but not the latter being specifically responsive to the presence of GA or ABA. The in vitro DGPP phosphatase activity was not modified by short time incubation with GA or ABA while the in vitro PA kinase - that allows the production of 18:2-DGPP from 18:2-PA - is stimulated by ABA. The long term effects (24 h) of ABA or GA on lipid and fatty acid composition of aleurone layer cells were then investigated. An increase in PC and, to a lesser extent, in PE levels is the consequence of both hormone treatments. ABA, in aleurone layer cells, specifically activates a PLD whose product, PA, could be the substrate of PAP1 and/or PAK activities. Neither PLD nor PAK activation can be monitored by GA treatment. The increase in PAP1 activity monitored after ABA or GA treatment might participate in the increase in PC level observed after 24 h hormone incubation.
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Affiliation(s)
- Ana Laura Villasuso
- Química Biológica, FCEFQN, Universidad Nacional de Río Cuarto, X5804BYA Río Cuarto, Córdoba, Argentina.
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18
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Gaveglio VL, Pasquaré SJ, Giusto NM. Phosphatidic acid metabolism in rat liver cell nuclei. FEBS Lett 2013; 587:950-6. [DOI: 10.1016/j.febslet.2013.01.074] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 11/22/2012] [Accepted: 01/02/2013] [Indexed: 11/28/2022]
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19
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Lysoglycerophospholipids in chronic inflammatory disorders: The PLA2/LPC and ATX/LPA axes. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:42-60. [DOI: 10.1016/j.bbalip.2012.07.019] [Citation(s) in RCA: 172] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 07/20/2012] [Accepted: 07/24/2012] [Indexed: 02/08/2023]
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20
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Kok BPC, Venkatraman G, Capatos D, Brindley DN. Unlike two peas in a pod: lipid phosphate phosphatases and phosphatidate phosphatases. Chem Rev 2012; 112:5121-46. [PMID: 22742522 DOI: 10.1021/cr200433m] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Bernard P C Kok
- Signal Transduction Research Group, Department of Biochemistry, School of Translational Medicine, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
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21
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Aaltonen N, Lehtonen M, Varonen K, Goterris GA, Laitinen JT. Lipid phosphate phosphatase inhibitors locally amplify lysophosphatidic acid LPA1 receptor signalling in rat brain cryosections without affecting global LPA degradation. BMC Pharmacol 2012; 12:7. [PMID: 22686545 PMCID: PMC3418163 DOI: 10.1186/1471-2210-12-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 06/11/2012] [Indexed: 11/10/2022] Open
Abstract
Background Lysophosphatidic acid (LPA) is a signalling phospholipid with multiple biological functions, mainly mediated through specific G protein-coupled receptors. Aberrant LPA signalling is being increasingly implicated in the pathology of common human diseases, such as arteriosclerosis and cancer. The lifetime of the signalling pool of LPA is controlled by the equilibrium between synthesizing and degradative enzymatic activity. In the current study, we have characterized these enzymatic pathways in rat brain by pharmacologically manipulating the enzymatic machinery required for LPA degradation. Results In rat brain cryosections, the lifetime of bioactive LPA was found to be controlled by Mg2+-independent, N-ethylmaleimide-insensitive phosphatase activity, attributed to lipid phosphate phosphatases (LPPs). Pharmacological inhibition of this LPP activity amplified LPA1 receptor signalling, as revealed using functional autoradiography. Although two LPP inhibitors, sodium orthovanadate and propranolol, locally amplified receptor responses, they did not affect global brain LPA phosphatase activity (also attributed to Mg2+-independent, N-ethylmaleimide-insensitive phosphatases), as confirmed by Pi determination and by LC/MS/MS. Interestingly, the phosphate analog, aluminium fluoride (AlFx-) not only irreversibly inhibited LPP activity thereby potentiating LPA1 receptor responses, but also totally prevented LPA degradation, however this latter effect was not essential in order to observe AlFx--dependent potentiation of receptor signalling. Conclusions We conclude that vanadate- and propranolol-sensitive LPP activity locally guards the signalling pool of LPA whereas the majority of brain LPA phosphatase activity is attributed to LPP-like enzymatic activity which, like LPP activity, is sensitive to AlFx- but resistant to the LPP inhibitors, vanadate and propranolol.
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Affiliation(s)
- Niina Aaltonen
- School of Pharmacy, University of Eastern Finland, P,O, Box 1627, 70211, Kuopio, Finland.
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22
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Hornberger TA. Mechanotransduction and the regulation of mTORC1 signaling in skeletal muscle. Int J Biochem Cell Biol 2011; 43:1267-76. [PMID: 21621634 PMCID: PMC3146557 DOI: 10.1016/j.biocel.2011.05.007] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 05/11/2011] [Accepted: 05/12/2011] [Indexed: 12/20/2022]
Abstract
Mechanical stimuli play a major role in the regulation of skeletal muscle mass, and the maintenance of muscle mass contributes significantly to disease prevention and issues associated with the quality of life. Although the link between mechanical signals and the regulation of muscle mass has been recognized for decades, the mechanisms involved in converting mechanical information into the molecular events that control this process remain poorly defined. Nevertheless, our knowledge of these mechanisms is advancing and recent studies have revealed that signaling through a protein kinase called the mammalian target of rapamycin (mTOR) plays a central role in this event. In this review we will, (1) discuss the evidence which implicates mTOR in the mechanical regulation of skeletal muscle mass, (2) provide an overview of the mechanisms through which signaling by mTOR can be regulated, and (3) summarize our current knowledge of the potential mechanisms involved in the mechanical activation of mTOR signaling.
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Affiliation(s)
- Troy A Hornberger
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, 2015 Linden Drive, Madison, WI 53706, USA.
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23
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Regulation of Phosphatidic Acid Levels in Trypanosoma cruzi. Lipids 2011; 46:969-79. [DOI: 10.1007/s11745-011-3577-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 05/09/2011] [Indexed: 10/18/2022]
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Gaveglio VL, Pasquaré SJ, Giusto NM. Metabolic pathways for the degradation of phosphatidic acid in isolated nuclei from cerebellar cells. Arch Biochem Biophys 2011; 507:271-80. [PMID: 21216221 DOI: 10.1016/j.abb.2011.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 12/29/2010] [Accepted: 01/03/2011] [Indexed: 11/28/2022]
Abstract
The aim of the present research was to analyse the pathways for phosphatidic acid metabolism in purified nuclei from cerebellar cells. Lipid phosphate phosphatase and diacylglyceride lipase activities were detected in nuclei from cerebellar cells. It was observed that DAGL activity makes up 50% of LPP activity and that PtdOH can also be metabolised to lysophosphatidic acid. With a nuclear protein content of approximately 40 μg, the production of diacylglycerol and monoacylglycerol was linear for 30 min and 5 min, respectively, whereas it increased with PtdOH concentrations of up to 250 μM. LysoPtdOH, sphingosine 1-phosphate and ceramide 1-phosphate, which are alternative substrates for LPP, significantly reduced DAG production from PA. DAG and MAG production increased in the presence of Triton X-100 (1 mM) whereas no modifications were observed in the presence of ionic detergent sodium deoxycholate. Ca²+ and Mg²+ stimulated MAG production without affecting DAG formation whereas fluoride and vanadate inhibited the generation of both products. Specific PtdOH-phospholipase A1 and PtdOH-phospholipase A2 were also detected in nuclei. Our findings constitute the first reported evidence of active PtdOH metabolism involving LPP, DAGL and PtdOH-selective PLA activities in purified nuclei prepared from cerebellar cells.
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Affiliation(s)
- Virginia L Gaveglio
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C.C. 857, B8000FWB Bahía Blanca, Argentina
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Pasquaré SJ, Gaveglio VL, Giusto NM. Age-related changes in the metabolization of phosphatidic acid in rat cerebral cortex synaptosomes. Arch Biochem Biophys 2009; 488:121-9. [PMID: 19691145 DOI: 10.1016/j.abb.2009.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In this study, phosphatidic acid (PA) metabolization is found to generate diacylglycerol (DAG), monoacylglycerol (MAG) and glycerol by the sequential action of lipid phosphate phosphatase (LPP), diacylglycerol lipase (DAGL), and monoacylglycerol lipase (MAGL) in cerebral cortex (CC) synaptosomes. It is also demonstrated that PA is metabolized by phospholipases A (PLA)/lysophosphatidic acid phosphohydrolase (LPAPase) in synaptic endings. Age-related changes in the metabolization of PA have been observed in rat cerebral cortex synaptosomes in the presence of the alternative substrates for LPP, namely LPA, sphingosine 1-phosphate (S1P) and ceramide 1-phosphate (C1P). In addition, LPA and C1P up to concentrations of about 50 microM favor the metabolism in the direction of MAG and glycerol in aged and adult synaptosomes, respectively. At equimolecular concentrations with PA, LPA decreases DAG formation in adult and aged synaptosomes, whereas S1P decreases it and C1P increases it only in aged synaptosomes. Sphingosine (50 microM) or ceramide (100 microM) increase PA metabolism by the pathway that involves LPP/DAGL/MAGL action in aged membranes. Using RHC-80267, a DAGL inhibitor, we could observe that 50% and 33% of MAG are produced as a result of DAGL action in adult and aged synaptosomes, respectively. Taken together, our findings indicate that the ageing modifies the different enzymatic pathways involved in PA metabolization.
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Affiliation(s)
- S J Pasquaré
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C.C. 857, B8000FWB Bahía Blanca, Argentina.
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Theofilopoulos S, Lykidis A, Leondaritis G, Mangoura D. Novel function of the human presqualene diphosphate phosphatase as a type II phosphatidate phosphatase in phosphatidylcholine and triacylglyceride biosynthesis pathways. Biochim Biophys Acta Mol Cell Biol Lipids 2008; 1781:731-42. [DOI: 10.1016/j.bbalip.2008.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Revised: 08/29/2008] [Accepted: 09/11/2008] [Indexed: 11/27/2022]
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Racagni G, Villasuso AL, Pasquaré SJ, Giusto NM, Machado E. Diacylglycerol pyrophosphate inhibits the alpha-amylase secretion stimulated by gibberellic acid in barley aleurone. PHYSIOLOGIA PLANTARUM 2008; 134:381-93. [PMID: 18573189 DOI: 10.1111/j.1399-3054.2008.01148.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
ABA plays an important regulatory role in seed germination because it inhibits the response to GA in aleurone, a secretory tissue surrounding the endosperm. Phosphatidic acid (PA) is a well-known intermediary in ABA signaling, but the role of diacylglycerol pyrophosphate (DGPP) in germination processes is not clearly established. In this study, we show that PA produced by phospholipase D (E.C. 3.1.4.4) during the antagonist effect of ABA in GA signaling is rapidly phosphorylated by phosphatidate kinase (PAK) to DGPP. This is a crucial fact for aleurone function because exogenously added dioleoyl-DGPP inhibits secretion of alpha-amylase (E.C. 3.2.1.1). Aleurone treatment with ABA and 1-butanol results in normal secretory activity, and this effect is reversed by addition of dioleoyl-DGPP. We also found that ABA decreased the activity of an Mg2+-independent, N-ethylmaleimide-insensitive form of phosphatidate phosphohydrolase (PAP2) (E.C. 3.1.3.4), leading to reduction of PA dephosphorylation and increased PAK activity. Sequence analysis using Arabidopsis thaliana lipid phosphate phosphatase (LPP) sequences as queries identified two putative molecular homologues, termed HvLPP1 and HvLPP2, encoding putative Lpps with the presence of well-conserved structural Lpp domains. Our results are consistent with a role of DGPP as a regulator of ABA antagonist effect in GA signaling and provide evidence about regulation of PA level by a PAP2 during ABA response in aleurone.
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Affiliation(s)
- Graciela Racagni
- Química Biológica, FCEFQN, Universidad Nacional de Río Cuarto, X5804BYA Río Cuarto, Córdoba, Argentina
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Diacylglyceride lipase activity in rod outer segments depends on the illumination state of the retina. Neurochem Int 2008; 53:382-8. [PMID: 18926868 DOI: 10.1016/j.neuint.2008.09.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Revised: 08/14/2008] [Accepted: 09/15/2008] [Indexed: 11/20/2022]
Abstract
We have demonstrated that the competition between phosphatidic acid (PA) and lysophosphatidic acid (LPA), sphingosine 1-phosphate (S1P) and ceramide 1-phosphate (C1P) for lipid phosphate phosphatases (LPP) generates different levels of diacylglycerol (DAG) depending on the illumination state of the retina. The aim of the present research was to determine the diacylglyceride lipase (DAGL) activity in purified rod outer segments (ROS) obtained from dark-adapted retinas (DROS) or light-adapted retinas (BLROS) as well as in ROS membrane preparations depleted of soluble and peripheral proteins. [2-(3)H]monoacylglycerol (MAG), the product of DAGL, was evaluated from [2-(3)H]DAG generated by LPP action on [2-(3)H]PA in the presence of either LPA, S1P or C1P. MAG production was inhibited by 55% in BLROS and by 25% when the enzymatic assay was carried out in ROS obtained from dark-adapted retinas and incubated under room light (LROS). The most important events occurred in DROS where co-incubation of [2-(3)H]PA with LPA, S1P or C1P diminished MAG production. A higher level of DAGL activity was observed in LROS than in BLROS, though this difference was not apparent in the presence of LPA, S1P or C1P. DAGL activity in depleted DROS was diminished with respect to that in entire DROS. LPA, S1P and C1P produced a similar decrease in MAG production in depleted DROS whereas only C1P significantly diminished MAG generation in depleted BLROS. Sphingosine and ceramide inhibited MAG production in entire DROS and stimulated its generation in BLROS. Sphingosine and ceramide stimulated MAG generation in both depleted DROS and BLROS. Under our experimental conditions the degree of MAG production depended on the illumination state of the retina. We therefore suggest that proteins related to phototransduction phenomena are involved in the effects observed in the presence of S1P/sphingosine or C1P/ceramide.
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Pasquaré SJ, Salvador GA, Giusto NM. Involvement of Lysophosphatidic Acid, Sphingosine 1-Phosphate and Ceramide 1-Phosphate in the Metabolization of Phosphatidic Acid by Lipid Phosphate Phosphatases in Bovine Rod Outer Segments. Neurochem Res 2008; 33:1205-15. [DOI: 10.1007/s11064-007-9569-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Accepted: 12/12/2007] [Indexed: 12/29/2022]
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Kai M, Sakane F, Jia YJ, Imai SI, Yasuda S, Kanoh H. Lipid Phosphate Phosphatases 1 and 3 Are Localized in Distinct Lipid Rafts. ACTA ACUST UNITED AC 2006; 140:677-86. [PMID: 17005594 DOI: 10.1093/jb/mvj195] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Lipid phosphate phosphatases (LPPs), integral membrane proteins with six transmembrane domains, dephosphorylate a variety of extracellular lipid phosphates. Although LPP3 is already known to bind to Triton X-100-insoluble rafts, we here report that LPP1 is also associated with lipid rafts distinct from those harboring LPP3. We found that LPP1 was Triton X-100-soluble, but CHAPS-insoluble in LNCaP cells endogenously expressing LPP1 and several LPP1 cDNA-transfected cells including NIH3T3 fibroblasts. In addition to the non-ionic detergent insolubility, LPP1 further possessed several properties formulated for raft-localizing proteins as follows: first, the CHAPS-insolubility was resistant to the actin-disrupting drug cytochalasin D; second, the CHAPS-insoluble LPP1 floated in an Optiprep density gradient; third, the CHAPS insolubility of LPP1 was lost by cholesterol depletion; and finally, the subcellular distribution pattern of LPP1 exclusively overlapped with that of a raft marker, cholera toxin B subunit. Interestingly, confocal microscopic analysis showed that LPP1 was distributed to membrane compartments distinct from those of LPP3. Analysis using various LPP1/LPP3 chimeras revealed that their first extracellular regions determine the different Triton X-100 solubilities. These results indicate that LPP1 and LPP3 are distributed in distinct lipid rafts that may provide unique microenvironments defining their non-redundant physiological functions.
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Affiliation(s)
- Masahiro Kai
- Department of Biochemistry, Sapporo Medical University School of Medicine, West-17, South-1, Sapporo 060-8556
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31
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Pasquaré SJ, Salvador GA, Giusto NM. Age-associated changes of insulin action on the hydrolysis of diacylglycerol generated from phosphatidic acid. Comp Biochem Physiol B Biochem Mol Biol 2006; 144:311-8. [PMID: 16651016 DOI: 10.1016/j.cbpb.2006.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 03/10/2006] [Accepted: 03/11/2006] [Indexed: 11/16/2022]
Abstract
Age-related changes in insulin action on diacylglycerol (DAG) degradation was studied in rat cerebral cortex synaptosomes. The generation of monoacylglycerol (MAG) and water soluble products (WSP, glycerol plus glycerol-3-phosphate) from DAG was studied in cerebral cortex (CC) synaptosomes from adult (4-month-old) and aged (28-month-old) rats. Additionally, the effect of porcine insulin and tyrosine phosphorylation was evaluated in the same group of animals. In this study we demonstrate that the age-related increase in WSP generation was accompanied by unmodified MAG levels. In the presence of diacylglycerol lipase (DAG lipase) inhibitor, RHC-80267, a lower inhibitory effect on MAG production was observed in CC synaptosomes from aged rats with respect to that in adult membranes. Under these experimental conditions, WSP formation was only diminished in aged membranes. Insulin stimulated MAG and WSP formation at long incubation times (30 min) in adult animals, while it had an inhibitory effect in aged animals. Insulin plus vanadate (as tyrosine-phosphatase inhibitor) inhibited MAG production at short incubation times whereas the same effect was observed in aged animals at long times of incubation. WSP formation was stimulated by insulin plus vanadate both in adult and aged animals at 30 min of incubation. Our results show that insulin differentially modulates MAG and WSP production from exogenous PA in CC synaptosomes from aged rats compared with adult rats.
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Affiliation(s)
- S J Pasquaré
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, B8000FWB Bahía Blanca, Argentina
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Garcia-Murillas I, Pettitt T, Macdonald E, Okkenhaug H, Georgiev P, Trivedi D, Hassan B, Wakelam M, Raghu P. lazaro encodes a lipid phosphate phosphohydrolase that regulates phosphatidylinositol turnover during Drosophila phototransduction. Neuron 2006; 49:533-46. [PMID: 16476663 DOI: 10.1016/j.neuron.2006.02.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2005] [Revised: 11/30/2005] [Accepted: 02/01/2006] [Indexed: 10/25/2022]
Abstract
An essential step in Drosophila phototransduction is the hydrolysis of phosphatidylinositol 4,5 bisphosphate PI(4,5)P2 by phospholipase Cbeta (PLCbeta) to generate a second messenger that opens the light-activated channels TRP and TRPL. Although the identity of this messenger remains unknown, recent evidence has implicated diacylglycerol kinase (DGK), encoded by rdgA, as a key enzyme that regulates its levels, mediating both amplification and response termination. In this study, we demonstrate that lazaro (laza) encodes a lipid phosphate phosphohydrolase (LPP) that functions during phototransduction. We demonstrate that the synergistic activity of laza and rdgA regulates response termination during phototransduction. Analysis of retinal phospholipids revealed a reduction in phosphatidic acid (PA) levels and an associated reduction in phosphatidylinositol (PI) levels. Together our results demonstrate the contribution of PI depletion to the rdgA phenotype and provide evidence that depletion of PI and its metabolites might be a key signal for TRP channel activation in vivo.
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Affiliation(s)
- Isaac Garcia-Murillas
- Inositide Laboratory, Babraham Institute, Babraham Research Campus, Cambridge CB2 4AT, United Kingdom
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Sun L, Gu S, Sun Y, Zheng D, Wu Q, Li X, Dai J, Dai J, Ji C, Xie Y, Mao Y. Cloning and characterization of a novel human phosphatidic acid phosphatase type 2, PAP2d, with two different transcripts PAP2d_v1 and PAP2d_v2. Mol Cell Biochem 2005; 272:91-6. [PMID: 16010976 DOI: 10.1007/s11010-005-7640-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study reports the cloning and characterization of a novel human phosphatidic acid phosphatase type 2 isoform cDNAs (PAP2d) from the foetal brain cDNA library. The PAP2d gene is localized on chromosome 1p21.3. It contains six exons and spans 112 kb of the genomic DNA. By large-scale cDNA sequencing we found two splice variants of PAP2d, PAP2d_v1 and PAP2d_v2. The PAP2d_v1 cDNA is 1722 bp in length and spans an open reading frame from nucleotide 56 to 1021, encoding a 321aa protein. The PAP2d_v2 cDNA is 1707 bp in length encoding a 316aa protein from nucleotide 56-1006. The PAP2d_v1 cDNA is 15 bp longer than the PAP2d_v2 cDNA in the terminal of the fifth exon and it creates different ORF. Both of the proteins contain a well-conserved PAP2 motif. The PAP2d_v1 is mainly expressed in human brain, lung, kidney, testis and colon, while PAP2d_v2 is restricted to human placenta, skeletal muscle, and kidney. The two splice variants are co-expressed only in kidney.
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Affiliation(s)
- Liyun Sun
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, People's Republic of China
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Sigal Y, McDERMOTT M, Morris A. Integral membrane lipid phosphatases/phosphotransferases: common structure and diverse functions. Biochem J 2005; 387:281-93. [PMID: 15801912 PMCID: PMC1134956 DOI: 10.1042/bj20041771] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Phospholipids and sphingolipids play critical roles in signal transduction, intracellular membrane trafficking, and control of cell growth and survival. We discuss recent progress in the identification and characterization of a family of integral membrane proteins with central roles in bioactive lipid metabolism and signalling. These five groups of homologous proteins, which we collectively term LPTs (lipid phosphatases/phosphotransferases), are characterized by a core domain containing six transmembrane-spanning alpha-helices connected by extramembrane loops, two of which interact to form the catalytic site. LPT family members are localized to all major membrane compartments of the cell. The transmembrane topology of these proteins places their active site facing the lumen of endomembrane compartments or the extracellular face of the plasma membrane. Sequence conservation between the active site of the LPPs (lipid phosphate phosphatases), SPPs (sphingosine phosphate phosphatases) and the recently identified SMSs (sphingomyelin synthases) with vanadium-dependent fungal oxidases provides a framework for understanding their common catalytic mechanism. LPPs hydrolyse LPA (lysophosphatidic acid), S1P (sphingosine 1-phosphate) and structurally-related substrates. Although LPPs can dephosphorylate intracellularly generated substrates to control intracellular lipid metabolism and signalling, their best understood function is to regulate cell surface receptor-mediated signalling by LPA and S1P by inactivating these lipids at the plasma membrane or in the extracellular space. SPPs are intracellularly localized S1P-selective phosphatases, with key roles in the pathways of sphingolipid metabolism linked to control of cell growth and survival. The SMS enzymes catalyse the interconversion of phosphatidylcholine and ceramide with sphingomyelin and diacylglycerol, suggesting a pivotal role in both housekeeping lipid synthesis and regulation of bioactive lipid mediators. The remaining members of the LPT family, the LPR/PRGs (lipid phosphatase-related proteins/plasticity-related genes) and CSS2s (type 2 candidate sphingomyelin synthases), are presently much less well studied. These two groups include proteins that lack critical amino acids within the catalytic site, and could therefore not use the conserved LPT reaction mechanism to catalyse lipid phosphatase or phosphotransferase reactions. In this review, we discuss recent ideas about their possible biological activities and functions, which appear to involve regulation of cellular morphology and, possibly, lipid metabolism and signalling in the nuclear envelope.
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Affiliation(s)
- Yury J. Sigal
- Department of Cell and Developmental Biology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090, U.S.A
| | - Mark I. McDERMOTT
- Department of Cell and Developmental Biology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090, U.S.A
| | - Andrew J. Morris
- Department of Cell and Developmental Biology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090, U.S.A
- To whom correspondence should be addressed (email )
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Zhao Y, Usatyuk P, Cummings R, Saatian B, He D, Watkins T, Morris A, Spannhake E, Brindley D, Natarajan V. Lipid phosphate phosphatase-1 regulates lysophosphatidic acid-induced calcium release, NF-kappaB activation and interleukin-8 secretion in human bronchial epithelial cells. Biochem J 2005; 385:493-502. [PMID: 15461590 PMCID: PMC1134721 DOI: 10.1042/bj20041160] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
LPA (lysophosphatidic acid), a potent bioactive phospholipid, elicits diverse cellular responses through activation of the G-protein-coupled receptors LPA1-LPA4. LPA-mediated signalling is partially regulated by LPPs (lipid phosphate phosphatases; LPP-1, -2 and -3) that belong to the phosphatase superfamily. This study addresses the role of LPPs in regulating LPA-mediated cell signalling and IL-8 (interleukin-8) secretion in HBEpCs (human bronchial epithelial cells). Reverse transcription-PCR and Western blotting revealed the presence and expression of LPP-1-3 in HBEpCs. Exogenous [3H]oleoyl LPA was hydrolysed to [3H]-mono-oleoylglycerol. Infection of HBEpCs with an adenoviral construct of human LPP-1 for 48 h enhanced the dephosphorylation of exogenous LPA by 2-3-fold compared with vector controls. Furthermore, overexpression of LPP-1 partially attenuated LPA-induced increases in the intracellular Ca2+ concentration, phosphorylation of IkappaB (inhibitory kappaB) and translocation of NF-kappaB (nuclear factor-kappaB) to the nucleus, and almost completely prevented IL-8 secretion. Infection of cells with an adenoviral construct of the mouse LPP-1 (R217K) mutant partially attenuated LPA-induced IL-8 secretion without altering LPA-induced changes in intracellular Ca2+ concentration, phosphorylation of IkappaB, NF-kappaB activation or IL-8 gene expression. Our results identify LPP-1 as a key regulator of LPA signalling and IL-8 secretion in HBEpCs. Thus LPPs could represent potential targets in regulating leucocyte infiltration and airway inflammation.
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Affiliation(s)
- Yutong Zhao
- *Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21222, U.S.A
| | - Peter V. Usatyuk
- *Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21222, U.S.A
| | - Rhett Cummings
- *Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21222, U.S.A
| | - Bahman Saatian
- *Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21222, U.S.A
| | - Donghong He
- *Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21222, U.S.A
| | - Tonya Watkins
- *Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21222, U.S.A
| | - Andrew Morris
- †Department of Cell Biology, University of North Carolina, Chapel Hill, NC, U.S.A
| | - Ernst Wm. Spannhake
- ‡Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, U.S.A
| | - David N. Brindley
- §Department of Biochemistry and Signal Transduction Research Group, University of Alberta, Edmonton, Canada
| | - Viswanathan Natarajan
- *Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21222, U.S.A
- To whom correspondence should be addressed: Division of Pulmonary and Critical Care, Johns Hopkins University Medical School, Mason F. Lord Building, Center Tower, 675, 5200 Eastern Avenue, Baltimore, MD, U.S.A. (email )
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Heasley BH, Jarosz R, Carter KM, Van SJ, Lynch KR, Macdonald TL. A novel series of 2-pyridyl-containing compounds as lysophosphatidic acid receptor antagonists: development of a nonhydrolyzable LPA3 receptor-selective antagonist. Bioorg Med Chem Lett 2005; 14:4069-74. [PMID: 15225728 DOI: 10.1016/j.bmcl.2004.05.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2004] [Revised: 05/11/2004] [Accepted: 05/12/2004] [Indexed: 11/22/2022]
Abstract
A recently reported dual LPA(1)/LPA(3) receptor antagonist (1) has been modified so as to modulate the basicity, sterics, and dipole moment of the 2-pyridyl moiety. Additionally, the implications of installing nonhydrolyzable phosphate head group isosteres with regard to antagonist potency and selectivity at LPA receptors is described. This study has resulted in the development of the first nonhydrolyzable and presumably phosphatase-resistant LPA(3)-selective antagonist reported to date.
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Affiliation(s)
- Brian H Heasley
- Department of Chemistry, University of Virginia, PO Box 400319, McCormick Road, Charlottesville, VA 22904, USA.
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Abstract
Lysophosphatidic acid (LPA) elicits diverse cellular responses through cell surface LPA receptors in nervous system-derived cells and cell lines. The developing nervous system is one of the major loci for LPA receptor expression. Recent studies have also revealed that metabolic pathways of LPA are present in the nervous system. A growing body of literature suggests a crucial role for LPA in neuronal development processes, including neurogenesis, neuronal migration, neuritogenesis, and myelination.
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Affiliation(s)
- Nobuyuki Fukushima
- Department of Biochemistry, Hokkaido University Graduate School of Medicine, N15W7, Kita-ku, Sapporo 060-8638, Japan
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38
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Miyamoto S, Hirata M, Yamazaki A, Kageyama T, Hasuwa H, Mizushima H, Tanaka Y, Yagi H, Sonoda K, Kai M, Kanoh H, Nakano H, Mekada E. Heparin-binding EGF-like growth factor is a promising target for ovarian cancer therapy. Cancer Res 2004; 64:5720-7. [PMID: 15313912 DOI: 10.1158/0008-5472.can-04-0811] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ovarian cancer is the most frequent cause of cancer death among all gynecologic cancers. We demonstrate here that lysophosphatidic acid (LPA)-induced ectodomain shedding of heparin-binding EGF-like growth factor (HB-EGF) is a critical to tumor formation in ovarian cancer. We found that among the epidermal growth factor receptor (EGFR) family of growth factors, HB-EGF gene expression in cancerous tissues and HB-EGF protein levels in patients' ascites fluid were significantly elevated. The human ovarian cancer cell lines SKOV3 and RMG-1 form tumors in nude mice. Tumor formation of these cells was enhanced by exogenous expression of pro-HB-EGF and completely blocked by pro-HB-EGF gene RNA interference or by CRM197, a specific HB-EGF inhibitor. Transfection with mutant forms of HB-EGF indicated that the release of soluble HB-EGF is essential for tumor formation. LPA, which is constitutively produced by ovarian cancer cells, induced HB-EGF ectodomain shedding in SKOV3 and RMG-1 cells, resulting in the transactivation of EGFR and the downstream kinase extracellular signal-regulated kinase/mitogen-activated protein kinase. LPA-induced transactivation was abrogated by HB-EGF gene RNA interference or by CRM197. Introduction of lipid phosphate phosphohydrolase, which hydrolyzes LPA, decreased the constitutive shedding of HB-EGF, EGFR transactivation, and the tumorigenic potential of SKOV3 and RMG-1 cells. These results indicate that HB-EGF is the primary member of the EGFR family of growth factors expressed in ovarian cancer and that LPA-induced ectodomain shedding of this growth factor is a critical step in tumor formation, making HB-EGF a novel therapeutic target for ovarian cancer.
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Affiliation(s)
- Shingo Miyamoto
- Department of Obstetrics and Gynecology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Pasquaré SJ, Salvador GA, Giusto NM. Phospholipase D and phosphatidate phosphohydrolase activities in rat cerebellum during aging. Lipids 2004; 39:553-60. [PMID: 15554154 DOI: 10.1007/s11745-004-1262-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Aging is a process that affects different organs, of which the brain is particularly susceptible. PA and DAG are central intermediates in the phosphoglyceride as well as in the neutral lipid biosynthetic pathway, and they have also been implicated in signal transduction. Phospholipase D (PLD) and phosphatidate phosphohydrolase (PAP) are the enzymes that generate PA and DAG. The latter can be transformed into MAG by diacylglycerol lipase (DGL). In the present study, we examine how aging modulates the PLD, PAP, and DGL isoforms in cerebellar subcellular fractions from 4- (adult), 28-, and 33-mon-old (aged) rats. PI-4,5-bisphosphonate (PIP2)-dependent PLD, PAP1, and DGL1 were distributed in different percentages in all cerebellum subcellular fractions. On the other hand, PAP2 and DGL2 activities were observed in all subcellular fractions except in the cytosolic fraction. Aging modified the enzyme distribution pattern. In addition, aging decreased nuclear (45%), mitochondrial-synaptosomal (55%), and cytosolic (71%) PAP1 activity and increased (28%) microsomal PAP1 activity. DGL1 activity was decreased in nuclear (85%) and mitochondrial-synaptosomal (63%) fractions by aging. On the other hand, PIP2-dependent PLD activities were increased in the mitochondrial-synaptosomal fraction. PAP2 and DGL2 were increased in the microsomal fraction by 87 and 114%, respectively, and they were decreased in the nuclear fraction. The changes observed in cerebellum PAP1 and DGL1 activities from aged rats with respect to adult rats could be related to modifications in lipid metabolism. Differential PA metabolization during aging through PIP2-dependent PLD/PAP2/DGL2 activities could be related to alterations in the neural signal transduction mechanisms.
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Affiliation(s)
- S J Pasquaré
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), B8000FWB Bahía Blanca, Argentina
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40
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Jia YJ, Kai M, Wada I, Sakane F, Kanoh H. Differential localization of lipid phosphate phosphatases 1 and 3 to cell surface subdomains in polarized MDCK cells. FEBS Lett 2003; 552:240-6. [PMID: 14527693 DOI: 10.1016/s0014-5793(03)00931-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Lipid phosphate phosphatases (LPPs) are integral membrane proteins with six transmembrane domains that act as ecto-enzymes dephosphorylating a variety of extracellular lipid phosphates. Using polarized MDCK cells stably expressing human LPP1 and LPP3, we found that LPP1 was located exclusively at the apical surface whereas LPP3 was distributed mostly in the basolateral subdomain. We identified a novel apical sorting signal at the N-terminus of LPP1 composed of F(2)DKTRL(7). In the case of LPP3, a dityrosine motif present in the second cytoplasmic portion was identified as basolateral targeting signal. Our work shows that LPP1 and LPP3 are equipped with distinct sorting signals that cause them to differentially localize to the apical vs. the basolateral subdomain, respectively.
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Affiliation(s)
- Yan-Jun Jia
- Department of Biochemistry, Sapporo Medical University School of Medicine, South-1, West-17, 060-8556 Sapporo, Japan
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Smyth SS, Sciorra VA, Sigal YJ, Pamuklar Z, Wang Z, Xu Y, Prestwich GD, Morris AJ. Lipid phosphate phosphatases regulate lysophosphatidic acid production and signaling in platelets: studies using chemical inhibitors of lipid phosphate phosphatase activity. J Biol Chem 2003; 278:43214-23. [PMID: 12909631 DOI: 10.1074/jbc.m306709200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Blood platelets play an essential role in ischemic heart disease and stroke contributing to acute thrombotic events by release of potent inflammatory agents within the vasculature. Lysophosphatidic acid (LPA) is a bioactive lipid mediator produced by platelets and found in the blood and atherosclerotic plaques. LPA receptors on platelets, leukocytes, endothelial cells, and smooth muscle cells regulate growth, differentiation, survival, motility, and contractile activity. Definition of the opposing pathways of synthesis and degradation that control extracellular LPA levels is critical to understanding how LPA bioactivity is regulated. We show that intact platelets and platelet membranes actively dephosphorylate LPA and identify the major enzyme responsible as lipid phosphate phosphatase 1 (LPP1). Localization of LPP1 to the platelet surface is increased by exposure to LPA. A novel receptor-inactive sn-3-substituted difluoromethylenephosphonate analog of phosphatidic acid that is a potent competitive inhibitor of LPP1 activity potentiates platelet aggregation and shape change responses to LPA and amplifies LPA production by agonist-stimulated platelets. Our results identify LPP1 as a pivotal regulator of LPA signaling in the cardiovascular system. These findings are consistent with genetic and cell biological evidence implicating LPPs as negative regulators of lysophospholipid signaling and suggest that the mechanisms involve both attenuation of lysophospholipid actions at cell surface receptors and opposition of lysophospholipid production.
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Affiliation(s)
- Susan S Smyth
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, California 92093-0668, USA
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42
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Hasegawa Y, Erickson JR, Goddard GJ, Yu S, Liu S, Cheng KW, Eder A, Bandoh K, Aoki J, Jarosz R, Schrier AD, Lynch KR, Mills GB, Fang X. Identification of a phosphothionate analogue of lysophosphatidic acid (LPA) as a selective agonist of the LPA3 receptor. J Biol Chem 2003; 278:11962-9. [PMID: 12554733 DOI: 10.1074/jbc.m209168200] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lysophosphatidic acid (LPA) is a bioactive lysophospholipid mediator that acts through G protein-coupled receptors. Most cell lines in culture express one or more LPA receptors, making it difficult to assign a response to specific LPA receptors. Dissection of the signaling properties of LPA has been hampered by lack of LPA receptor subtype-specific agonists and antagonists. The present study characterizes an ester-linked thiophosphate derivative (1-oleoyl-2-O-methyl-rac-glycerophosphothionate, OMPT) of LPA. OMPT is a functional LPA analogue with potent mitogenic activity in fibroblasts. In contrast to LPA, OMPT does not couple to the pheromone response through the LPA(1) receptor in yeast cells. OMPT induces intracellular calcium increases efficiently in LPA(3) receptor-expressing Sf9 cells but poorly in LPA(2) receptor-expressing cells. Guanosine 5'-O-(3-[(35)S]thio)triphosphate binding assays in mammalian cells showed that LPA exhibits agonistic activity on all three LPA receptor subtypes, whereas OMPT has a potent agonistic effect only on the LPA(3) receptor. In transiently transfected HEK293 cells, OMPT stimulates mitogen-activated protein kinases through the LPA(3) but not the LPA(1) or LPA(2) receptors. Furthermore, OMPT-induced intracellular calcium mobilization in mammalian cells is efficiently inhibited by the LPA(1)/LPA(3) receptor-selective antagonist VPC12249. These results establish that OMPT is an LPA(3)-selective agonist. OMPT binding to the LPA(3) receptor in mammalian cells is sufficient to elicit multiple responses, including activation of G proteins, calcium mobilization, and activation of mitogen-activated protein kinases. Thus OMPT offers a powerful probe for the dissection of LPA signaling events in complex mammalian systems.
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Nanjundan M, Possmayer F. Pulmonary phosphatidic acid phosphatase and lipid phosphate phosphohydrolase. Am J Physiol Lung Cell Mol Physiol 2003; 284:L1-23. [PMID: 12471011 DOI: 10.1152/ajplung.00029.2002] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The lung contains two distinct forms of phosphatidic acid phosphatase (PAP). PAP1 is a cytosolic enzyme that is activated through fatty acid-induced translocation to the endoplasmic reticulum, where it converts phosphatidic acid (PA) to diacylglycerol (DAG) for the biosynthesis of phospholipids and neutral lipids. PAP1 is Mg(2+) dependent and sulfhydryl reagent sensitive. PAP2 is a six-transmembrane-domain integral protein localized to the plasma membrane. Because PAP2 degrades sphingosine-1-phosphate (S1P) and ceramide-1-phosphate in addition to PA and lyso-PA, it has been renamed lipid phosphate phosphohydrolase (LPP). LPP is Mg(2+) independent and sulfhydryl reagent insensitive. This review describes LPP isoforms found in the lung and their location in signaling platforms (rafts/caveolae). Pulmonary LPPs likely function in the phospholipase D pathway, thereby controlling surfactant secretion. Through lowering the levels of lyso-PA and S1P, which serve as agonists for endothelial differentiation gene receptors, LPPs regulate cell division, differentiation, apoptosis, and mobility. LPP activity could also influence transdifferentiation of alveolar type II to type I cells. It is considered likely that these lipid phosphohydrolases have critical roles in lung morphogenesis and in acute lung injury and repair.
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Affiliation(s)
- Meera Nanjundan
- Department of Obstetrics and Gynaecology, Canadian Institutes of Health Research Group in Fetal and Neonatal Health and Development, The University of Western Ontario, 339 Windermere Road, London, Ontario, Canada N6A 5A5
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44
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Giusto NM, Salvador GA, Castagnet PI, Pasquaré SJ, Ilincheta de Boschero MG. Age-associated changes in central nervous system glycerolipid composition and metabolism. Neurochem Res 2002; 27:1513-23. [PMID: 12512956 DOI: 10.1023/a:1021604623208] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In this review, changes in brain lipid composition and metabolism due to aging are outlined. The most striking changes in cerebral cortex and cerebellum lipid composition involve an increase in acidic phospholipid synthesis. The most important changes with respect to fatty acyl composition involve a decreased content in polyunsaturated fatty acids (20:4n-6, 22:4n-6, 22:6n-3) and an increased content in monounsaturated fatty acids (18:1n-9 and 20:1n-9), mainly in ethanolamine and serineglycerophospholipids. Changes in the activity of the enzymes modifying the phospholipid headgroup occur during aging. Serine incorporation into phosphatidylserine through base-exchange reactions and phosphatidylcholine synthesis through phosphatidylethanolamine methylation increases in the aged brain. Phosphatidate phosphohydrolase and phospholipase D activities are also altered in the aged brain thus producing changes in the lipid second messengers diacylglycerol and phosphatidic acid.
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Affiliation(s)
- N M Giusto
- Instituto de Investigaciones Bioquímicas, Universidad Nacional del Sur y Consejo Nacional de Investigaciones Cientificas y Técnicas, B8000FWB Bahía Blanca, Argentina.
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45
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Simon MF, Rey A, Castan-Laurel I, Grés S, Sibrac D, Valet P, Saulnier-Blache JS. Expression of ectolipid phosphate phosphohydrolases in 3T3F442A preadipocytes and adipocytes. Involvement in the control of lysophosphatidic acid production. J Biol Chem 2002; 277:23131-6. [PMID: 11956205 PMCID: PMC2000479 DOI: 10.1074/jbc.m201530200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Because of its production by adipocytes and its ability to increase preadipocyte proliferation, lysophosphatidic acid (LPA) could participate in the paracrine control of adipose tissue development. The aim of the present study was to determine which enzyme activities are involved in exogenous LPA hydrolysis by preadipocytes and adipocytes. Using a quantitative method, we observed that extracellular LPA rapidly disappeared from the culture medium of 3T3F442A preadipocytes. This disappearance was strongly slowed down in the presence of the phosphatase inhibitors, sodium vanadate and sodium pervanadate. By using [(33)P]LPA on intact 3T3F442A preadipocytes, we found that 90% of LPA hydrolysis resulted from LPA phosphatase activity biochemically related to previously described ectolipid phosphate phosphohydrolases (LPPs). Quantitative real time reverse transcriptase-PCR revealed that 3T3F442A preadipocytes expressed mRNAs of three known Lpp gene subtypes (1, 2, and 3), with a predominant expression of Lpp1 and Lpp3. Differentiation of 3T3F442A preadipocytes into adipocytes led to an 80% reduction in ecto-LPA phosphatase activity, with a concomitant down-regulation in Lpp1, Lpp2, and Lpp3 mRNA expression. Despite this regulation, treatment of 3T3F442A adipocytes with sodium vanadate increased LPA production in the culture medium, suggesting the involvement of ecto-LPA phosphatase activity in the control of extracellular production of LPA by adipocytes. In conclusion, these data demonstrate that hydrolysis of extracellular LPA by preadipocytes and adipocytes mainly results from a dephosphorylation activity. This activity (i) occurs at the extracellular face of cell membrane, (ii) exhibits biochemical characteristics similar to those of the LPP, (iii) is negatively regulated during adipocyte differentiation, and (iv) plays an important role in the control of extracellular LPA production by adipocytes. Ecto-LPA phosphatase activity represents a potential target to control adipose tissue development.
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Salvador GA, Pasquaré SJ, Ilincheta de Boschero MG, Giusto NM. Differential modulation of phospholipase D and phosphatidate phosphohydrolase during aging in rat cerebral cortex synaptosomes. Exp Gerontol 2002; 37:543-52. [PMID: 11830357 DOI: 10.1016/s0531-5565(01)00214-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Phosphatidylcholine (PC) hydrolysis generates two important second messengers: phosphatidic acid (PA) and diacylglycerol (DAG). Phospholipase D (PLD) and phosphatidate phosphohydrolase (PAPase) are involved in their generation and therefore are key enzymes in signal transduction. Specific isoforms of these enzymes are activated by receptor occupancy in brain. Phosphatidylinositol 4,5-bisphosphate-dependent PLD (PIP2-PLD) and N-ethylmaleimide-insensitive PAPase (PAP2) have been suggested to act in series to generate the biologically active lipids PA and DAG. In the present study we examine age-induced changes mainly in PIP2-PLD and PAP2 activities in cerebrocortical synaptosomes from adult (4 months) and aged (28 months) Wistar rats. Aging increases the activity of both enzymes. Guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) and cytosol (from cerebral cortex) stimulate PLD activity in adult and senescent synaptosomal membranes, the effect being greater in the latter. Under the same experimental conditions PAP2 activity was stimulated in aged membranes whereas in adult membranes GTPgammaS had no effect and cytosol showed a slight inhibitory effect. Diacylglycerol lipase (DGL) activity differs from that of PAP2 in aged rats and it was 21% inhibited with respect to synaptosomal membranes from adult rats. Increased sinaptosomal PLD activity in aged membranes appears to be independent of G protein regulation, whereas PAP2 activity is differentially regulated by GTPgammaS in aged membranes with respect to adult membranes. Our results suggest that under G-protein activation conditions, DAG production by the serial activation of PLD and PAP2 activities is increased in synaptosomal membranes from aged brain. The present paper demonstrates that PA generation (PLD activity) and degradation (PAPase activity) are differentially modulated during the aging process.
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Affiliation(s)
- G A Salvador
- Instituto de Investigaciones Bioquímicas, Universidad Nacional del Sur y Consejo Nacional de Investigaciones Científicas y Técnicas, C.C. 857, B8000FWB, Bahía Blanca, Argentina
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Nanjundan M, Possmayer F. Molecular cloning and expression of pulmonary lipid phosphate phosphohydrolases. Am J Physiol Lung Cell Mol Physiol 2001; 281:L1484-93. [PMID: 11704545 DOI: 10.1152/ajplung.2001.281.6.l1484] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pulmonary lipid phosphate phosphohydrolase (LPP) was shown previously to hydrolyze phosphatidic acid and lysophosphatidic acid in purified rat lung plasma membranes. To better investigate the nature of pulmonary LPP isoforms and their role in the lung, LPPs were cloned by RT-PCR from both adult rat lung and type II cell RNA. The RT-PCR generated LPP1 (849 bp), up to three LPP1 variants, and LPP3 (936 bp) cDNAs. The three LPP1 variants include LPP1a (852 bp) and two novel isoforms, LPP1b (697 bp) and LPP1c (1004 bp). The pulmonary LPP1 and LPP3 isoforms are essentially identical to the previously cloned rat liver and intestinal LPPs, respectively, and the LPP1a isoform has 80% sequence identity to the human homolog. The LPP2 isoform was not detected in lung by RT-PCR. Northern analyses revealed that the mRNAs for LPP1 and LPP3 increase in fetal rat lung in late gestation to day 1 after birth. These mRNAs decrease somewhat during the neonatal period but increase slightly during postnatal development. Expression of LPP1, LPP1a, and LPP3 cDNAs in HEK 293 cells established that they encode functional LPP. In contrast, the novel isoforms LPP1b and LPP1c contain frameshifts that would result in premature termination, producing putative catalytically inactive polypeptides of 30 and 76 amino acids, respectively. Further investigation of the LPP1b isoform revealed that it was present across a variety of tissues, although at lower levels than LPP1/1a. Transient mammalian expression of LPP1b failed to increase phosphatidate phosphohydrolase activity in HEK 293 cells.
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Affiliation(s)
- M Nanjundan
- Medical Research Council Group in Fetal and Neonatal Health and Development, Department of Biochemistry, University of Western Ontario, London, Ontario, Canada N6A 5A5
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Pasquaré SJ, Ilincheta de Boschero MG, Giusto NM. Aging promotes a different phosphatidic acid utilization in cytosolic and microsomal fractions from brain and liver. Exp Gerontol 2001; 36:1387-401. [PMID: 11602212 DOI: 10.1016/s0531-5565(01)00106-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Among the morphological and biochemical changes taking place in the membranes of aged tissues, we reported in previous studies on alterations in phospholipid synthesis and phospholipid-specific fatty acid composition. Phosphatidic acid (PA) and diacylglycerol (DAG) are central intermediates in phosphoglyceride and neutral lipid biosynthetic pathways and have also recently been implicated in signal transduction. The present paper shows the effect of aging on phosphatidate phosphohydrolase (PAPase) activiy, which operates on phosphatidic acid to synthesize diacylglycerol. Two forms of mammalian PAPase can be indentified on the basis of subcellular localization and enzyme properties, one involved predominantly in lipid synthesis (PAP 1) and the other in signal transduction (PAP 2). Microsomal and cytosolic fractions of brain and liver from 3.5-month-old (adult) and 28.5-month-old (aged) rats were used. PAPase isoform activities were differentiated on the basis of N-ethylmaleimide (NEM) sensitivity and Mg(2+)-dependency. Our results demonstrate that aging caused PAP 2 to increase in brain microsomal fractions but did not affect PAP 1, whereas in brain cytosolic fractions, it caused a strong decrease in PAP 1 (57%). The distribution of enzymes between microsomes and cytosol changed in aged rats with respect to adult rats, showing a translocation of PAP 1 from cytosol to microsomes. In addition, an increase in the production of monoacylglycerol (MAG) was observed in microsomes from aged brain. PAP 2 activity in liver microsomal fractions from aged rats showed no changes with respect to adult rats whereas PAP 1 activity increased 228% in microsomal fractions and 76% in cytosolic fractions in this tissue. The distribution of PAP 1 activity between microsomal and cytosolic fractions in liver tissue was also affected in aged rats, indicating a translocation of this form of the enzyme from cytosolic to microsomal fractions. The production of monoacylglycerol in liver microsomes also increased, whereas there was a decrease in MAG formation from cytosolic fraction. The changes observed in the two PAPase forms in brain and liver of aged rats with respect to adult rats suggest that PA is differently utilized by the PAPase isoforms, probably generating aging-related DAGs different to those present in adults and required for specific cellular functions. The changes observed in liver PAP 1 from aged with respect to adult rats suggest that such changes could be related with modifications in lipid homeostasis induced by age-altered hormonal balance. However, PA-modified utilization during aging through PAP 2 activity could be related to alterations in neural signal transduction mechanisms.
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Affiliation(s)
- S J Pasquaré
- Instituto de Investigaciones Bioquímicas, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas, CC 857, B8000FWB Bahía Blanca, Argentina
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Alderton F, Darroch P, Sambi B, McKie A, Ahmed IS, Pyne N, Pyne S. G-protein-coupled receptor stimulation of the p42/p44 mitogen-activated protein kinase pathway is attenuated by lipid phosphate phosphatases 1, 1a, and 2 in human embryonic kidney 293 cells. J Biol Chem 2001; 276:13452-60. [PMID: 11278307 DOI: 10.1074/jbc.m006582200] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sphingosine 1-phosphate, lysophosphatidic acid, and phosphatidic acid bind to G-protein-coupled receptors to stimulate intracellular signaling in mammalian cells. Lipid phosphate phosphatases (1, 1a, 2, and 3) are a group of enzymes that catalyze de-phosphorylation of these lipid agonists. It has been proposed that the lipid phosphate phosphatases exhibit ecto activity that may function to limit bioavailability of these lipid agonists at their receptors. In this study, we show that the stimulation of the p42/p44 mitogen-activated protein kinase pathway by sphingosine 1-phosphate, lysophosphatidic acid, and phosphatidic acid, all of which bind to G(i/o)-coupled receptors, is substantially reduced in human embyronic kidney 293 cells transfected with lipid phosphate phosphatases 1, 1a, and 2 but not 3. This was correlated with reduced basal intracellular phosphatidic acid and not ecto lipid phosphate phosphatase activity. These findings were supported by results showing that lipid phosphate phosphatases 1, 1a, and 2 also abrogate the stimulation of p42/p44 mitogen-activated protein kinase by thrombin, a peptide G(i/o)-coupled receptor agonist whose bioavailability at its receptor is not subject to regulation by the phosphatases. Furthermore, the lipid phosphate phosphatases have no effect on the stimulation of p42/p44 mitogen-activated protein kinase by other agents that do not use G-proteins to signal, such as serum factors and phorbol ester. Therefore, these findings show that the lipid phosphate phosphatases 1, 1a, and 2 may function to perturb G-protein-coupled receptor signaling per se rather than limiting bioavailability of lipid agonists at their respective receptors.
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Affiliation(s)
- F Alderton
- Department of Physiology and Pharmacology, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, 27 Taylor St., Glasgow, G4 0NR, United Kingdom
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Lynch KR, Macdonald TL. Structure activity relationships of lysophospholipid mediators. Prostaglandins Other Lipid Mediat 2001; 64:33-45. [PMID: 11324706 DOI: 10.1016/s0090-6980(01)00106-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- K R Lynch
- Department of Pharmacology, University of Virginia, Charlottesville, USA.
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