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Salabi F, Jafari H. Whole transcriptome sequencing reveals the activity of the PLA2 family members in Androctonus crassicauda (Scorpionida: Buthidae) venom gland. FASEB J 2024; 38:e23658. [PMID: 38742809 DOI: 10.1096/fj.202400178rr] [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: 01/23/2024] [Revised: 04/21/2024] [Accepted: 04/25/2024] [Indexed: 05/16/2024]
Abstract
Phospholipase A2 is the most abundant venom gland enzyme, whose activity leads to the activation of the inflammatory response by accumulating lipid mediators. This study aimed to identify, classify, and investigate the properties of venom PLA2 isoforms. Then, the present findings were confirmed by chemically measuring the activity of PLA2. The sequences representing PLA2 annotation were extracted from the Androctonus crassicauda transcriptome dataset using BLAS searches against the local PLA2 database. We found several cDNA sequences of PLA2 classified and named by conducting multiple searches as platelet-activating factor acetylhydrolases, calcium-dependent PLA2s, calcium-independent PLA2s, and secreted PLA2s. The largest and smallest isoforms of these proteins range between approximately 70.34 kDa (iPLA2) and 17.75 kDa (cPLA2). Among sPLA2 isoforms, sPLA2GXIIA and sPLA2G3 with ORF encoding 169 and 299 amino acids are the smallest and largest secreted PLA2, respectively. These results collectively suggested that A. crassicauda venom has PLA2 activity, and the members of this protein family may have important biological roles in lipid metabolism. This study also revealed the interaction between members of PLA2s in the PPI network. The results of this study would greatly help with the classification, evolutionary relationships, and interactions between PLA2 family proteins in the gene network.
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Affiliation(s)
- Fatemeh Salabi
- Department of Venomous Animals and Anti-venom Production, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Ahvaz, Iran
| | - Hedieh Jafari
- Department of Venomous Animals and Anti-venom Production, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Ahvaz, Iran
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Classes of Lipid Mediators and Their Effects on Vascular Inflammation in Atherosclerosis. Int J Mol Sci 2023; 24:ijms24021637. [PMID: 36675152 PMCID: PMC9863938 DOI: 10.3390/ijms24021637] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/06/2023] [Accepted: 01/08/2023] [Indexed: 01/18/2023] Open
Abstract
It is commonly believed that the inactivation of inflammation is mainly due to the decay or cessation of inducers. In reality, in connection with the development of atherosclerosis, spontaneous decay of inducers is not observed. It is now known that lipid mediators originating from polyunsaturated fatty acids (PUFAs), which are important constituents of all cell membranes, can act in the inflamed tissue and bring it to resolution. In fact, PUFAs, such as arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), are precursors to both pro-inflammatory and anti-inflammatory compounds. In this review, we describe the lipid mediators of vascular inflammation and resolution, and their biochemical activity. In addition, we highlight data from the literature that often show a worsening of atherosclerotic disease in subjects deficient in lipid mediators of inflammation resolution, and we also report on the anti-proteasic and anti-thrombotic properties of these same lipid mediators. It should be noted that despite promising data observed in both animal and in vitro studies, contradictory clinical results have been observed for omega-3 PUFAs. Many further studies will be required in order to clarify the observed conflicts, although lifestyle habits such as smoking or other biochemical factors may often influence the normal synthesis of lipid mediators of inflammation resolution.
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PLA2G7/PAF-AH as Potential Negative Regulator of the Wnt Signaling Pathway Mediates Protective Effects in BRCA1 Mutant Breast Cancer. Int J Mol Sci 2023; 24:ijms24010882. [PMID: 36614323 PMCID: PMC9821466 DOI: 10.3390/ijms24010882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 12/23/2022] [Accepted: 12/29/2022] [Indexed: 01/05/2023] Open
Abstract
Past studies have confirmed that aberrant activation of the Wnt/β-catenin signaling is associated with tumorigenesis and metastasis in breast cancer, while the role of platelet-activating factor acetylhydrolase (PLA2G7/PAF-AH) in this signaling pathway remains unclear. In this study, we analyze the functional impact of PAF-AH on BRCA1 mutant breast cancer and explore its relationship to the Wnt signaling pathway. By performing immunohistochemistry, PAF-AH expression and β-catenin expression were examined in both BRCA1 WT and BRCA1 mutant breast cancer specimens. The BRCA1 mutant breast cancer cell line HCC1937 was used for in vitro experiments to assess the impact of PAF-AH on cellular functions. The intracellular distribution of β-catenin depending on PLA2G7/PAF-AH expression was investigated by immunocytochemistry. Significantly higher nuclear expression levels of PAF-AH were found in BRCA1 mutant tissue specimens than in BRCA1 WT samples. Cell viability, proliferation, and the motility rate of HCC1937 were significantly enhanced after PLA2G7 silencing, which indicated a protective role of PAF-AH in breast cancer. Nuclear PAF-AH expressed correlatedly with membranous β-catenin. PLA2G7 silencing provoked the β-catenin translocation from the membrane to the nucleus and activated Wnt signaling downstream genes. Our data showed a protective effect of high PAF-AH expression in BRCA1 mutant breast cancer. PAF-AH may achieve its protective effect by negatively regulating the Wnt pathway. In conclusion, our research sheds new light on the regulatory pathways in BRCA1 mutant breast cancer.
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Firdous P, Hassan T, Farooq S, Nissar K. Applications of proteomics in cancer diagnosis. Proteomics 2023. [DOI: 10.1016/b978-0-323-95072-5.00014-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
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Tanigawa K, Kiriya M, Hayashi Y, Shinden Y, Kijima Y, Natsugoe S, Sumimoto T, Morimoto-Kamata R, Yui S, Hama K, Yokoyama K, Nakamura Y, Suzuki K, Nojiri H, Inoue K, Karasawa K. Cathepsin G-induced malignant progression of MCF-7 cells involves suppression of PAF signaling through induced expression of PAFAH1B2. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159164. [PMID: 35462067 DOI: 10.1016/j.bbalip.2022.159164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 04/01/2022] [Accepted: 04/14/2022] [Indexed: 10/18/2022]
Abstract
Breast cancer is primarily classified into ductal and lobular types, as well as into noninvasive and invasive cancer. Invasive cancer involves lymphatic and hematogenous metastasis. In breast cancer patients with distant metastases, a neutrophil-derived serine protease; cathepsin G (Cat G), is highly expressed in breast cancer cells. Cat G induces cell migration and multicellular aggregation of MCF-7 human breast cancer cells; however, the mechanism is not clear. Recently, platelet-activating factor (PAF)-acetylhydrolase (PAF-AH), the enzyme responsible for PAF degradation, was reported to be overexpressed in some tumor types, including pancreatic and breast cancers. In this study, we investigated whether PAF-AH is involved in Cat G-induced aggregation and migration of MCF-7 cells. We first showed that Cat G increased PAF-AH activity and elevated PAFAH1B2 expression in MCF-7 cells. The elevated expression of PAFAH1B2 was also observed in human breast cancer tissue specimens by immunohistochemical analysis. Furthermore, knockdown of PAFAH1B2 in MCF-7 cells suppressed the cell migration and aggregation induced by low concentrations, but not high concentrations, of Cat G. Carbamoyl PAF (cPAF), a nonhydrolyzable PAF analog, completely suppressed Cat G-induced migration of MCF-7 cells. In addition, PAF receptor (PAFR) inhibition induced cell migration of MCF-7 cells even in the absence of Cat G, suggesting that Cat G suppresses the activation of PAFR through enhanced PAF degradation due to elevated expression of PAFAH1B2 and thereby induces malignant phenotypes in MCF-7 cells. Our findings may lead to a novel therapeutic modality for treating breast cancer by modulating the activity of Cat G/PAF signaling.
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Affiliation(s)
- Kazunari Tanigawa
- Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan
| | - Mitsuo Kiriya
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan
| | - Yasuhiro Hayashi
- Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan
| | - Yoshiaki Shinden
- Department of Digestive Surgery, Breast and Thyroid Surgery, Kagoshima University, Kagoshima-shi, Kagoshima 890-8580, Japan
| | - Yuko Kijima
- Department of Digestive Surgery, Breast and Thyroid Surgery, Kagoshima University, Kagoshima-shi, Kagoshima 890-8580, Japan; Department of Breast Surgery, School of Medicine, Fujita Health University, Toyooka-shi, Aichi 470-1192, Japan
| | - Shoji Natsugoe
- Department of Neurosurgery, Kajiki-Onsen Hospital, Aira-shi, Kagoshima 899-5241, Japan
| | - Takahiro Sumimoto
- Department of Clinical Pharmacy, Oita University Hospital, Yufu-shi, Oita 879-5593, Japan
| | - Riyo Morimoto-Kamata
- Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan
| | - Satoru Yui
- Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan
| | - Kotaro Hama
- Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan
| | - Kazuaki Yokoyama
- Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan
| | - Yasuhiro Nakamura
- Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan
| | - Koichi Suzuki
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan
| | - Hisao Nojiri
- Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan
| | - Keizo Inoue
- Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan
| | - Ken Karasawa
- Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan.
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He Y, He Z, Zhang X, Liu S. Platelet-activating factor acetyl hydrolase IB2 dysregulated cell proliferation in ovarian cancer. Cancer Cell Int 2021; 21:697. [PMID: 34930255 PMCID: PMC8690939 DOI: 10.1186/s12935-021-02406-9] [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] [Received: 10/28/2021] [Accepted: 12/09/2021] [Indexed: 11/10/2022] Open
Abstract
Background Ovarian cancer is the leading cause of death from gynaecologic illnessed worldwide. Platelet-activating factor acetyl hydrolase IB2 (PAF-AH IB2) is an intracellular serine esterase that hydrolyzes platelet-activating factor, a G-protein-like trimer with two catalytic subunits and one regulatory subunit. The regulatory role of PAF-AH IB2 in the oncogenesis of ovarian cancer is not well understood. Methods In this study, the TCGA dataset and clinical cancer tissue microarray were utilized to investigate abnormal overexpression of PAF-AH IB2 in ovarian cancer. To investigate the impact on the cell proliferation, migration, and tumorigenicity in vitro, PAF-AH IB2 stable knocking down (KD) ovarian cancer cells were established by ShRNA. The whole transcription profiling, tyrosine kinase profiling and standard cell functional assays were integrated to explore the biological importance and mechanism of PAF-AH IB2 modulated in ovarian cancer. Results PAF-AH IB2 was identified significantly overexpression in four subtypes of ovarian cancer. In vitro, PAF-AH IB2 KD significantly inhibited cancer cell proliferation, migration, and tumorigenicity, activated caspases and caused cell cycle arrest, and made the cells more sensitive to PAF. PAF-AH 1B2 KD cells down-regulated several key regulators of the multiple tyrosine kinases-mediated signaling pathway, suggesting a novel interaction network between the growth factor receptors pathway and PAF-AH 1B2 mediated PAF signalling. Conclusions These findings revealed a previously undiscovered role for PAF-AH IB2 as a potenial therapy target and essential signaling mediators in ovarian cancer pathogenesis, as well as new possible preventive and therapeutic strategies to inhibit this enzyme in clinical treatment for ovarian cancer. Supplementary Information The online version contains supplementary material available at 10.1186/s12935-021-02406-9.
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Affiliation(s)
- YingYing He
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, #132 Lanhei Road, Panlong District, Kunming, 650201, Yunnan, People's Republic of China.,School of Chemical Science & Technology, Yunnan University, Kunming, 650091, Yunnan, China
| | - Zhicheng He
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, #132 Lanhei Road, Panlong District, Kunming, 650201, Yunnan, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaoyu Zhang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, #132 Lanhei Road, Panlong District, Kunming, 650201, Yunnan, People's Republic of China
| | - Shubai Liu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, #132 Lanhei Road, Panlong District, Kunming, 650201, Yunnan, People's Republic of China. .,University of Chinese Academy of Sciences, Beijing, 100049, China.
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Platelet-Activating Factor Acetylhydrolase Expression in BRCA1 Mutant Ovarian Cancer as a Protective Factor and Potential Negative Regulator of the Wnt Signaling Pathway. Biomedicines 2021; 9:biomedicines9070706. [PMID: 34206491 PMCID: PMC8301368 DOI: 10.3390/biomedicines9070706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 06/12/2021] [Accepted: 06/17/2021] [Indexed: 11/17/2022] Open
Abstract
Aberrantly activated Wnt/β-catenin signaling pathway, as well as platelet-activating factor (PAF), contribute to cancer progression and metastasis of many cancer entities. Nonetheless, the role of the degradation enzyme named platelet-activating factor acetylhydrolase (PLA2G7/PAF-AH) in ovarian cancer etiology is still unclear. This study investigated the functional impact of platelet-activating factor acetylhydrolase on BRCA1 mutant ovarian cancer biology and its crosstalk with the Wnt signaling pathway. PAF-AH, pGSK3β, and β-catenin expressions were analyzed in 156 ovarian cancer specimens by immunohistochemistry. PAF-AH expression was investigated in ovarian cancer tissue, serum of BRCA1-mutated patients, and in vitro in four ovarian cancer cell lines. Functional assays were performed after PLA2G7 silencing. The association of PAF-AH and β-catenin was examined by immunocytochemistry. In an established ovarian carcinoma collective, we identified PAF-AH as an independent positive prognostic factor for overall survival (median 59.9 vs. 27.4 months; p = 0.016). PAF-AH correlated strongly with the Wnt signaling proteins pGSK3β (Y216; nuclear: cc = 0.494, p < 0.001; cytoplasmic: cc = 0.488, p < 0.001) and β-catenin (nuclear: cc = 0.267, p = 0.001; cytoplasmic: cc = 0.291, p < 0.001). In particular, high levels of PAF-AH were found in tumor tissue and in the serum of BRCA1 mutation carriers. By in vitro expression analysis, a relevant gene and protein expression of PLA2G7/PAF-AH was detected exclusively in the BRCA1-negative ovarian cancer cell line UWB1.289 (p < 0.05). Functional assays showed enhanced viability, proliferation, and motility of UWB1.289 cells when PLA2G7/PAF-AH was downregulated, which underlines its protective character. Interestingly, by siRNA knockdown of PLA2G7/PAF-AH, the immunocytochemistry staining pattern of β-catenin changed from a predominantly membranous expression to a nuclear one, suggesting a negative regulatory role of PAF-AH on the Wnt/β-catenin pathway. Our data provide evidence that PAF-AH is a positive prognostic factor with functional impact, which seems particularly relevant in BRCA1 mutant ovarian cancer. For the first time, we show that its protective character may be mediated by a negative regulation of the Wnt/β-catenin pathway. Further studies need to specify this effect. Potential use of PAF-AH as a biomarker for predicting the disease risk of BRCA1 mutation carriers and for the prognosis of patients with BRCA1-negative ovarian cancer should be explored.
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Dong L, Li Y, Wu H. Platelet activating-factor acetylhydrolase II: A member of phospholipase A2 family that hydrolyzes oxidized phospholipids. Chem Phys Lipids 2021; 239:105103. [PMID: 34116047 DOI: 10.1016/j.chemphyslip.2021.105103] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/09/2021] [Accepted: 06/05/2021] [Indexed: 10/21/2022]
Abstract
Intracellular platelet activating-factor acetylhydrolase type II (PAF-AH II) is a 40-kDa monomeric enzyme. It was originally identified as an enzyme that hydrolyzes the acetyl group of PAF (1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine). As a member of phospholipase A2 super family, PAF-AH II has broad substrate specificity. It can hydrolyze phospholipids with relatively short-length or oxidatively modified sn-2 chains which endows it with various functions such as protection against oxidative stress, transacetylase activity and producing lipid mediators. PAF-AH II has been proven to be involved in several diseases such as allergic diseases, oxidative stress-induced injury and ischemia injury, thus it has drawn more attention from researchers. In this paper, we outline an entire summary of PAF-AH II, including its structure, substrate specificity, activity assay, inhibitors and biological activities.
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Affiliation(s)
- Linyue Dong
- Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yiming Li
- Department of TCM Chemistry, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
| | - Huali Wu
- Department of TCM Chemistry, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
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Russo E, Lauritano C, d'Ippolito G, Fontana A, Sarno D, von Elert E, Ianora A, Carotenuto Y. RNA-Seq and differential gene expression analysis in Temora stylifera copepod females with contrasting non-feeding nauplii survival rates: an environmental transcriptomics study. BMC Genomics 2020; 21:693. [PMID: 33023465 PMCID: PMC7541278 DOI: 10.1186/s12864-020-07112-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 09/29/2020] [Indexed: 12/30/2022] Open
Abstract
Background Copepods are fundamental components of pelagic food webs, but reports on how molecular responses link to reproductive success in natural populations are still scarce. We present a de novo transcriptome assembly and differential expression (DE) analysis in Temora stylifera females collected in the Gulf of Naples, Mediterranean Sea, where this copepod dominates the zooplankton community. High-Throughput RNA-Sequencing and DE analysis were performed from adult females collected on consecutive weeks (May 23rd and 30th 2017), because opposite naupliar survival rates were observed. We aimed at detecting key genes that may have influenced copepod reproductive potential in natural populations and whose expression was potentially affected by phytoplankton-derived oxylipins, lipoxygenase-derived products strongly impacting copepod naupliar survival. Results On the two sampling dates, temperature, salinity, pH and oxygen remained stable, while variations in phytoplankton cell concentration, oxylipin concentration and oxylipin-per-diatom-cell production were observed. T. stylifera naupliar survival was 25% on May 23rd and 93% on May 30th. De novo assembly generated 268,665 transcripts (isoforms) and 120,749 unique ‘Trinity predicted genes’ (unigenes), of which 50% were functionally annotated. Out of the 331 transcript isoforms differentially expressed between the two sampling dates, 119 sequences were functionally annotated (58 up- and 61 down-regulated). Among predicted genes (unigenes), 144 sequences were differentially expressed and 31 (6 up-regulated and 25 down-regulated) were functionally annotated. Most of the significantly down-regulated unigenes and isoforms were A5 Putative Odorant Binding Protein (Obp). Other differentially expressed sequences (isoforms and unigenes) related to developmental metabolic processes, protein ubiquitination, response to stress, oxidation-reduction reactions and hydrolase activities. DE analysis was validated through Real Time-quantitative PCR of 9 unigenes and 3 isoforms. Conclusions Differential expression of sequences involved in signal detection and transduction, cell differentiation and development offered a functional interpretation to the maternally-mediated low naupliar survival rates observed in samples collected on May 23rd. Down-regulation of A5 Obp along with higher quantities of oxylipins-per-litre and oxylipins-per-diatom-cell observed on May 23rd could suggest oxylipin-mediated impairment of naupliar survival in natural populations of T. stylifera. Our results may help identify biomarker genes explaining variations in copepod reproductive responses at a molecular level.
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Affiliation(s)
- Ennio Russo
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.,Consiglio Nazionale delle Ricerche, Institute of Biomolecular Chemistry, Via Campi Flegrei 34, 80078, Pozzuoli, Italy
| | - Chiara Lauritano
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Giuliana d'Ippolito
- Consiglio Nazionale delle Ricerche, Institute of Biomolecular Chemistry, Via Campi Flegrei 34, 80078, Pozzuoli, Italy
| | - Angelo Fontana
- Consiglio Nazionale delle Ricerche, Institute of Biomolecular Chemistry, Via Campi Flegrei 34, 80078, Pozzuoli, Italy
| | - Diana Sarno
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Eric von Elert
- Universität zu Köln, Aquatic Chemical Ecology Group, Zülpicher Straβe 47b, D-50674, Cologne, Germany
| | - Adrianna Ianora
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Ylenia Carotenuto
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
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G994T polymorphism in exon 9 of plasma platelet-activating factor acetylhydrolase gene and lung ultrasound score as prognostic markers in evaluating the outcome of acute respiratory distress syndrome. Exp Ther Med 2019; 17:3174-3180. [PMID: 30906481 DOI: 10.3892/etm.2019.7281] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 11/07/2018] [Indexed: 12/21/2022] Open
Abstract
The present study aimed to discover potential biomarkers for predicting the prognosis of acute respiratory distress syndrome (ARDS) in conjunction with lung ultrasound (LUS). Blood samples from 112 ARDS patients were collected to compare their partial oxygen pressure (PaO2)/fraction of inspired oxygen (FiO2), positive end-expiratory pressure (PEEP), lactic acid, sequential organ failure assessment (SOFA) score, clinical pulmonary infection score (CPIS) and APACHE II score. Kaplan-Meier plots and the log-rank test were performed to analyse the association between the platelet-activating factor acetylhydrolase (PAFAH) G994T polymorphism and the outcome of ARDS regarding mortality. A negative correlation between the LUS score and PaO2/FiO2, PEEP and lactic acid, as well as with the SOFA, CPIS and APACHE II score was confirmed with correlation coefficients of -0.493, -0.548, -0.642, -0.598, -0.566 and -0.567, respectively (all P<0.05). The activity of PAFAH and high-density lipoprotein-PAFAH in the serum collected from subjects of the GG genotype was similar to that in subjects of the GT genotype, but the low-density lipoprotein-PAFAH activity in the serum collected from GG subjects was significantly higher than that in GT subjects. An evident reduction in the PEEP, level of lactic acid, as well as the SOFA, CPIS and APACHE II score was observed in GG subjects, accompanied by a significantly increased PaO2/FiO2. Kaplan-Meier analysis indicated that subjects with a high LUS score had a significantly higher survival rate than those with a low LUS score, and the mortality risk for GG subjects was significantly lower than that for GT subjects. Finally, among all groups (genotype and LUS groups), GG subjects with a high LUS score had the lowest mortality risk, whereas GT subjects with a low LUS score had the highest mortality risk. In addition, the survival rate of GT subjects with a high LUS score was higher than that of GG subjects with a low LUS score. In conclusion, the combination of the LUS score and the G994T polymorphism in exon 9 of the PAFAH gene may be used as a potential prognostic marker for ARDS.
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Kono N, Arai H. Platelet-activating factor acetylhydrolases: An overview and update. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:922-931. [PMID: 30055287 DOI: 10.1016/j.bbalip.2018.07.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 07/19/2018] [Accepted: 07/23/2018] [Indexed: 01/22/2023]
Abstract
Platelet-activating factor acetylhydrolases (PAF-AHs) are unique members of the phospholipase A2 family that can hydrolyze the acetyl group of PAF, a signaling phospholipid that has roles in diverse (patho)physiological processes. Three types of PAF-AH have been identified in mammals, one plasma type and two intracellular types [PAF-AH (I) and PAF-AH (II)]. Plasma PAF-AH and PAF-AH (II) are monomeric enzymes that are structurally similar, while PAF-AH (I) is a multimeric enzyme with no homology to other PAF-AHs. PAF-AH (I) shows a strong preference for an acetyl group, whereas plasma PAF-AH and PAF-AH (II) also hydrolyze phospholipids with oxidatively modified fatty acids. Plasma PAF-AH has been implicated in several diseases including cardiovascular disease. PAF-AH (I) is required for spermatogenesis and is increasingly recognized as an oncogenic factor. PAF-AH (II) was recently shown to act as a bioactive lipid-producing enzyme in mast cells and thus could be a drug target for allergic diseases. This article is part of a Special Issue entitled Novel functions of phospholipase A2 Guest Editors: Makoto Murakami and Gerard Lambeau.
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Affiliation(s)
- Nozomu Kono
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; PRIME, Japan Agency for Medical Research and Development, 1-7-1 Otemachi, Chiyodaku, Tokyo 100-0004, Japan.
| | - Hiroyuki Arai
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; AMED-CREST, Japan Agency for Medical Research and Development, 1-7-1 Otemachi, Chiyodaku, Tokyo 100-0004, Japan
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12
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Ma C, Guo Y, Zhang Y, Duo A, Jia Y, Liu C, Li B. PAFAH1B2 is a HIF1a target gene and promotes metastasis in pancreatic cancer. Biochem Biophys Res Commun 2018; 501:654-660. [PMID: 29758199 DOI: 10.1016/j.bbrc.2018.05.039] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 05/06/2018] [Indexed: 12/31/2022]
Abstract
Platelet-activating factor acetylhydrolase IB subunit beta (PAFAH1B2) plays important roles in inflammation and anaphylaxis. However, its primary function in pancreatic cancer remains unclear. In the current study, we report that PAFAH1B2 is overexpressed in pancreatic ductal adenocarcinoma (PDAC) and correlated inversely with patient survival. PAFAH1B2 overexpression induced epithelial-mesenchymal transition (EMT), migration and invasion in vitro and metastasis in vivo. Conversely, silencing PAFAH1B2 inhibited these aggressive phenotypes. Moreover, PAFAH1B2 overexpression in PDAC cells was directly mediated by HIF1a. PAFAH1B2 expression in PDAC clinical specimens correlated positively with HIF1a expression. Overall, our results defined PAFAH1B2 as a target gene of HIF1a and a critical driver of PDAC metastatic behaviors.
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Affiliation(s)
- Can Ma
- Department of General Surgery, Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Yan Guo
- Department of Oncology, The First Hospital of Shijiazhuang, Shijiazhuang, Hebei, China
| | - Yan Zhang
- Department of General Surgery, Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Aixia Duo
- Department of General Surgery, Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Yitao Jia
- Department of General Surgery, Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Ci Liu
- Department of General Surgery, Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Binghui Li
- Department of General Surgery, Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, Hebei, China.
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Li ZY, Chung YH, Shin EJ, Dang DK, Jeong JH, Ko SK, Nah SY, Baik TG, Jhoo JH, Ong WY, Nabeshima T, Kim HC. YY-1224, a terpene trilactone-strengthened Ginkgo biloba, attenuates neurodegenerative changes induced by β-amyloid (1-42) or double transgenic overexpression of APP and PS1 via inhibition of cyclooxygenase-2. J Neuroinflammation 2017; 14:94. [PMID: 28449688 PMCID: PMC5408406 DOI: 10.1186/s12974-017-0866-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 04/18/2017] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Ginkgo biloba has been reported to possess free radical-scavenging antioxidant activity and anti-inflammatory properties. In our pilot study, YY-1224, a terpene trilactone-strengthened extract of G. biloba, showed anti-inflammatory, neurotrophic, and antioxidant effects. RESULTS We investigated the pharmacological potential of YY-1224 in β-amyloid (Aβ) (1-42)-induced memory impairment using cyclooxygenase-2 (COX-2) knockout (-/-) and APPswe/PS1dE9 transgenic (APP/PS1 Tg) mice. Repeated treatment with YY-1224 significantly attenuated Aβ (1-42)-induced memory impairment in COX-2 (+/+) mice, but not in COX-2 (-/-) mice. YY-1224 significantly attenuated Aβ (1-42)-induced upregulation of platelet-activating factor (PAF) receptor gene expression, reactive oxygen species, and pro-inflammatory factors. In addition, YY-1224 significantly inhibited Aβ (1-42)-induced downregulation of PAF-acetylhydrolase-1 (PAF-AH-1) and peroxisome proliferator-activated receptor γ (PPARγ) gene expression. These changes were more pronounced in COX-2 (+/+) mice than in COX-2 (-/-) mice. YY-1224 significantly attenuated learning impairment, Aβ deposition, and pro-inflammatory microglial activation in APP/PS1 Tg mice, whereas it significantly enhanced PAF-AH and PPARγ expression. A preferential COX-2 inhibitor, meloxicam, did not affect the pharmacological activity by YY-1224, suggesting that the COX-2 gene is a critical mediator of the neuroprotective effects of YY-1224. The protective activity of YY-1224 appeared to be more efficacious than a standard G. biloba extract (Gb) against Aβ insult. CONCLUSIONS Our results suggest that the protective effects of YY-1224 against Aβ toxicity may be associated with its PAF antagonistic- and PPARγ agonistic-potential as well as inhibition of the Aβ-mediated pro-inflammatory switch of microglia phenotypes through suppression of COX-2 expression.
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Affiliation(s)
- Zheng-Yi Li
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341 Republic of Korea
| | - Yoon Hee Chung
- Department of Anatomy, College of Medicine, Chung-Ang University, Seoul, 06974 Republic of Korea
| | - Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341 Republic of Korea
| | - Duy-Khanh Dang
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341 Republic of Korea
| | - Ji Hoon Jeong
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, 06974 Republic of Korea
| | - Sung Kwon Ko
- Department of Oriental Medical Food and Nutrition, Semyung University, Jecheon, 27136 Republic of Korea
| | - Seung-Yeol Nah
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine and Bio/Molecular Informatics Center, Konkuk University, Seoul, 05029 Republic of Korea
| | - Tae Gon Baik
- R&D Center, Yuyu Pharma, Seoul, 04598 Republic of Korea
| | - Jin Hyeong Jhoo
- Department of Psychiatry, Medical School, Kangwon National University, Chunchon, 24341 Republic of Korea
| | - Wei-Yi Ong
- Department of Anatomy, National University of Singapore, Singapore, 119260 Singapore
| | - Toshitaka Nabeshima
- Nabeshima Laboratory, Graduate School of Pharmaceutical Sciences, Meijo University, Nagoya, 468-8503 Japan
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, 24341 Republic of Korea
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Crawford GL, Boldison J, Copland DA, Adamson P, Gale D, Brandt M, Nicholson LB, Dick AD. The role of lipoprotein-associated phospholipase A2 in a murine model of experimental autoimmune uveoretinitis. PLoS One 2015; 10:e0122093. [PMID: 25874928 PMCID: PMC4398387 DOI: 10.1371/journal.pone.0122093] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Accepted: 02/21/2015] [Indexed: 12/22/2022] Open
Abstract
Macrophage activation is, in part, regulated via hydrolysis of oxidised low density lipoproteins by Lipoprotein-Associated phospholipase A2 (Lp-PLA2), resulting in increased macrophage migration, pro-inflammatory cytokine release and chemokine expression. In uveitis, tissue damage is mediated as a result of macrophage activation; hence inhibition of Lp-PLA2 may limit macrophage activation and protect the tissue. Utilising Lp-PLA2 gene-deficient (KO) mice and a pharmacological inhibitor of Lp-PLA2 (SB-435495) we aimed to determine the effect of Lp-PLA2 suppression in mediating retinal protection in a model of autoimmune retinal inflammation, experimental autoimmune uveoretinitis (EAU). Following immunisation with RBP-3 (IRBP) 1–20 or 161–180 peptides, clinical disease was monitored and severity assessed, infiltrating leukocytes were enumerated by flow cytometry and tissue destruction quantified by histology. Despite ablation of Lp-PLA2 enzyme activity in Lp-PLA2 KO mice or wild-type mice treated with SB-435495, the number of infiltrating CD45+ cells in the retina was equivalent to control EAU animals, and there was no reduction in disease severity. Thus, despite the reported beneficial effects of therapeutic Lp-PLA2 depletion in a variety of vascular inflammatory conditions, we were unable to attenuate disease, show delayed disease onset or prevent progression of EAU in Lp-PLA2 KO mice. Although EAU exhibits inflammatory vasculopathy there is no overt defect in lipid metabolism and given the lack of effect following Lp-PLA2 suppression, these data support the hypothesis that sub-acute autoimmune inflammatory disease progresses independently of Lp-PLA2 activity.
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Affiliation(s)
- G. L. Crawford
- Academic unit of Ophthalmology, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - J. Boldison
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - D. A. Copland
- Academic unit of Ophthalmology, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - P. Adamson
- Ophthiris Discovery Performance Unit, GlaxoSmithKline, Stevenage, United Kingdom
| | - D. Gale
- Ophthiris Discovery Performance Unit, GlaxoSmithKline, King of Prussia, Pennsylvania, United States of America
| | - M. Brandt
- Platform Technology Sciences, King of Prussia, Pennsylvania, United States of America
| | - L. B. Nicholson
- Academic unit of Ophthalmology, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - A. D. Dick
- Academic unit of Ophthalmology, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
- * E-mail:
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Monillas ES, Caplan JL, Thévenin AF, Bahnson BJ. Oligomeric state regulated trafficking of human platelet-activating factor acetylhydrolase type-II. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:469-75. [PMID: 25707358 DOI: 10.1016/j.bbapap.2015.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/06/2015] [Accepted: 02/12/2015] [Indexed: 01/19/2023]
Abstract
The intracellular enzyme platelet-activating factor acetylhydrolase type-II (PAFAH-II) hydrolyzes platelet-activating factor and oxidatively fragmented phospholipids. PAFAH-II in its resting state is mainly cytoplasmic, and it responds to oxidative stress by becoming increasingly bound to endoplasmic reticulum and Golgi membranes. Numerous studies have indicated that this enzyme is essential for protecting cells from oxidative stress induced apoptosis. However, the regulatory mechanism of the oxidative stress response by PAFAH-II has not been fully resolved. Here, changes to the oligomeric state of human PAFAH-II were investigated as a potential regulatory mechanism toward enzyme trafficking. Native PAGE analysis in vitro and photon counting histogram within live cells showed that PAFAH-II is both monomeric and dimeric. A Gly-2-Ala site-directed mutation of PAFAH-II demonstrated that the N-terminal myristoyl group is required for homodimerization. Additionally, the distribution of oligomeric PAFAH-II is distinct within the cell; homodimers of PAFAH-II were localized to the cytoplasm while monomers were associated to the membranes of the endoplasmic reticulum and Golgi. We propose that the oligomeric state of PAFAH-II drives functional protein trafficking. PAFAH-II localization to the membrane is critical for substrate acquisition and effective oxidative stress protection. It is hypothesized that the balance between monomer and dimer serves as a regulatory mechanism of a PAFAH-II oxidative stress response.
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Affiliation(s)
- Elizabeth S Monillas
- Department of Chemistry & Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Jeffrey L Caplan
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Anastasia F Thévenin
- Department of Chemistry & Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Brian J Bahnson
- Department of Chemistry & Biochemistry, University of Delaware, Newark, DE 19716, USA.
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Klems MM, Bahnson BJ. Trafficking and Oligomeric Regulation of Platelet-Activating Factor Acetylhydrolase Type II. PLATELET-ACTIVATING FACTOR ACETYLHYDROLASES (PAF-AH) 2015; 38:55-69. [DOI: 10.1016/bs.enz.2015.09.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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17
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Kono N, Arai H. Intracellular Platelet-Activating Factor Acetylhydrolase, Type II. PLATELET-ACTIVATING FACTOR ACETYLHYDROLASES (PAF-AH) 2015; 38:43-54. [DOI: 10.1016/bs.enz.2015.09.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Nitoda E, Koutsilieris M, Brouzas D, Koutsandrea C, Philippou A, Ladas D, Moschos MM. Correlation of platelet activating factor and age-related macular degeneration. Expert Opin Ther Targets 2014; 18:987-97. [PMID: 25077601 DOI: 10.1517/14728222.2014.930439] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE To investigate the role of Platelet Activating Factor (PAF) in the pathogenesis and development of Age-Related Macular Degeneration (ARMD). RESEARCH DESIGN AND METHODS Fifty six patients with ARMD (24 patients with dry ARMD and 32 patients with wet ARMD) and 25 age-matched control participants underwent ophthalmological examination, including visual acuity measurement and evaluation of the retina. The participants were classified into three groups according to their retinal status, based on indirect fundoscopy, Optical Coherence Tomography and fluorescein angiography findings. In order to evaluate the concentrations of PAF in serum, blood samples were collected from all participants and were analyzed with ELISA technique. RESULTS The concentrations of PAF differed significantly according to macular lesions and were found to be lower in patients with ARMD than control participants. CONCLUSIONS PAF levels are decreased along with the severity of ARMD. Understanding the role of PAF in pathogenesis of ARMD could be the impetus for the development of new therapies field of treatment of ARMD or even other retinal diseases.
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Affiliation(s)
- Eirini Nitoda
- National and Kapodistrian University of Athens, 1st Department of Ophthalmology, Medical School , Athens , Greece +306944887319 ; +302104122319 ;
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Feng L, Zhao Y, Feng G, Chen Y. Clinical application of elevated platelet-activating factor acetylhydrolase in patients with hepatitis B. Lipids Health Dis 2014; 13:105. [PMID: 24973921 PMCID: PMC4096520 DOI: 10.1186/1476-511x-13-105] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 06/26/2014] [Indexed: 01/30/2023] Open
Abstract
Background The aim of this study was to investigate the variation of platelet-activating factor acetylhydrolase (PAF-AH) in patients with various stages of hepatitis B infection and evaluate the association between PAF-AH activity and chronic severe hepatitis B (CSHB) and mortality in patients with hepatitis B. Methods Serum PAF-AH activity was measured in 216 patients with hepatitis B and in 152 healthy controls using an automatic biochemical analysis system. Spearman correlation was used to investigate the correlation between PAF-AH activity and other biochemical indicators. The receiver operating characteristic (ROC) curve and multivariable logistic regression analysis were used to evaluate the ability of PAF-AH activity to predict CSHB and mortality in patients with hepatitis B. Results The PAF-AH activities in patients with CSHB (1320 ± 481 U/L) were significantly higher than those in healthy controls and in other hepatitis B groups (all P < 0.01). In patients with hepatitis B, PAF-AH activity correlated with total bilirubin (r = 0.633), total bile acid (r = 0.559), aspartate aminotransferase (r = 0.332), apolipoprotein B (r = 0.348), high-density lipoprotein cholesterol (r = −0.493), and apolipoprotein AI (r = −0.530). The areas under the ROC curves for the ability of PAF-AH activity to predict CSHB and mortality in patients with hepatitis B were 0.881 (95% confidence interval (CI): 0.824–0.937, P < 0.001) and 0.757 (95% CI: 0.677–0.837, P < 0.001), respectively. Multivariate logistic regression analysis showed PAF-AH activity to be an independent factor predicting CSHB with an odds ratio of 1.003 (95% CI: 1.002–1.005, P < 0.001). Conclusion Elevated PAF-AH in patients with hepatitis B was significantly associated with liver damage. Thus, serum PAF-AH could be used as a novel indicator for predicting CSHB and mortality in patients with hepatitis B. Further, PAF-AH activity was an independent factor predicting CSHB.
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Affiliation(s)
| | | | | | - Yu Chen
- Department of Laboratory Medicine, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China.
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Tarui M, Shindou H, Kumagai K, Morimoto R, Harayama T, Hashidate T, Kojima H, Okabe T, Nagano T, Nagase T, Shimizu T. Selective inhibitors of a PAF biosynthetic enzyme lysophosphatidylcholine acyltransferase 2. J Lipid Res 2014; 55:1386-96. [PMID: 24850807 PMCID: PMC4076079 DOI: 10.1194/jlr.m049205] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Indexed: 01/09/2023] Open
Abstract
Platelet-activating factor (PAF) is a potent pro-inflammatory phospholipid mediator. In response to extracellular stimuli, PAF is rapidly biosynthesized by lyso-PAF acetyltransferase (lyso-PAFAT). Previously, we identified two types of lyso-PAFATs: lysophosphatidylcholine acyltransferase (LPCAT)1, mostly expressed in the lungs where it produces PAF and dipalmitoyl-phosphatidylcholine essential for respiration, and LPCAT2, which biosynthesizes PAF and phosphatidylcholine (PC) in the inflammatory cells. Under inflammatory conditions, LPCAT2, but not LPCAT1, is activated and upregulated to produce PAF. Thus, it is important to develop inhibitors specific for LPCAT2 in order to ameliorate PAF-related inflammatory diseases. Here, we report the first identification of LPCAT2-specific inhibitors, N-phenylmaleimide derivatives, selected from a 174,000-compound library using fluorescence-based high-throughput screening followed by the evaluation of the effects on LPCAT1 and LPCAT2 activities, cell viability, and cellular PAF production. Selected compounds competed with acetyl-CoA for the inhibition of LPCAT2 lyso-PAFAT activity and suppressed PAF biosynthesis in mouse peritoneal macrophages stimulated with a calcium ionophore. These compounds had low inhibitory effects on LPCAT1 activity, indicating that adverse effects on respiratory functions may be avoided. The identified compounds and their derivatives will contribute to the development of novel drugs for PAF-related diseases and facilitate the analysis of LPCAT2 functions in phospholipid metabolism in vivo.
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Affiliation(s)
- Megumi Tarui
- Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan Department of Respiratory Medicine, Faculty of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hideo Shindou
- Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Kazuo Kumagai
- Open Innovation Center for Drug Discovery, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ryo Morimoto
- Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takeshi Harayama
- Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan
| | - Tomomi Hashidate
- Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan
| | - Hirotatsu Kojima
- Open Innovation Center for Drug Discovery, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takayoshi Okabe
- Open Innovation Center for Drug Discovery, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tetsuo Nagano
- Open Innovation Center for Drug Discovery, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takahide Nagase
- Department of Respiratory Medicine, Faculty of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takao Shimizu
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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Feng LM, Feng GF, Chen Y. Evaluation of lipoprotein-associated phospholipase A2 in healthy Chinese Han adult serum. Lipids Health Dis 2014; 13:6. [PMID: 24393260 PMCID: PMC3895822 DOI: 10.1186/1476-511x-13-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 01/03/2014] [Indexed: 12/13/2022] Open
Abstract
Objective The aim of this study is to establish lipoprotein-associated phospholipase A2 (Lp-PLA2) reference intervals (RIs) in healthy Chinese Han adults as a clinical diagnostic indicator according to the Clinical and Laboratory Standards Institute (CLSI) C28-A3 guidelines. Design and methods Lp-PLA2 levels in 763 healthy Chinese Han subjects (392 males and 371 females) were determined by colorimetric analysis and the central 95th percentile RIs were determined using non-parametric statistical methods. The correlations between serum Lp-PLA2 and blood markers were analyzed by Spearman correlation analyses. Results The Lp-PLA2 levels showed a Gaussian distribution with a statistically significant difference between females and males (t = 4.866, P < 0.001). The RIs of serum Lp-PLA2 were 194–640 U/L (18–49 years) and 208–698 U/L (50–88 years) for females, and 230–728 U/L for males. There was a positive correlation between Lp-PLA2 levels and age, Body Mass Index (BMI), as well as with levels of alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), total bilirubin (TBIL), triglyceride (TG), total cholesterol (Tch), low density lipoprotein cholesterol (LDL-c), apolipoprotein B (apoB), glucose (Glu), high sensitivity C reactive protein (Hs-CRP), white blood cell (WBC), hemoglobin (HGB) and red blood cell (RBC) (P < 0.05). A negative correlation was found with high density lipoprotein cholesterol (HDL-c) and Apolipoprotein AI (apoAI), and no correlation was found with platelet (Plt) levels. Conclusion Our results establish the RIs of serum Lp-PLA2 in healthy Chinese Han adults and demonstrate correlations between serum Lp-PLA2 and age, BMI, ALT, GGT, TBIL, TG, Tch, HDL-c, LDL-c, apoAI, apoB, Glu, Hs-CRP, WBC, RBC, and HGB levels.
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Affiliation(s)
| | | | - Yu Chen
- Department of Laboratory Medicine, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, P,R, China.
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Age-Related Macular Degeneration: Pathogenesis, Genetic Background, and the Role of Nutritional Supplements. J CHEM-NY 2014. [DOI: 10.1155/2014/317536] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Age-related macular degeneration (ARMD) is the leading cause of severe vision loss and blindness worldwide, mainly affecting people over 65 years old. Dry and wet ARDM are the main types of the disease, which seem to have a multifactorial background. The aim of this review is to summarize the mechanisms of ARMD pathogenesis and exhibit the role of diet and nutritional supplements in the onset and progression of the disease. Environmental factors, such as smoking, alcohol, and, diet appear to interact with mutations in nuclear and mitochondrial DNA, contributing to the pathogenesis of ARMD. Inflammatory mediators and oxidative stress, induced by the daily exposure of retina to high pressure of oxygen and light radiation, have been also associated with ARMD lesions. Other than medical and surgical therapies, nutritional supplements hold a significant role in the prevention and treatment of ARMD, eliminating the progression of macular degeneration.
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Tokuoka SM, Kita Y, Shindou H, Shimizu T. Alkylglycerol monooxygenase as a potential modulator for PAF synthesis in macrophages. Biochem Biophys Res Commun 2013; 436:306-12. [DOI: 10.1016/j.bbrc.2013.05.099] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 05/23/2013] [Indexed: 10/26/2022]
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Stafforini DM, McIntyre TM. Determination of phospholipase activity of PAF acetylhydrolase. Free Radic Biol Med 2013; 59:100-7. [PMID: 22659315 PMCID: PMC3444653 DOI: 10.1016/j.freeradbiomed.2012.05.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 05/17/2012] [Accepted: 05/18/2012] [Indexed: 02/07/2023]
Abstract
This article presents a radiometric assay to determine the enzymatic activity of platelet-activating factor (PAF) acetylhydrolase (PAF-AH), also known as lipoprotein-associated phospholipase A2 and phospholipase A2 group 7A. The method is based on the release of radioactively labeled acetate from sn-2-labeled PAF and separation of substrate and product using reversed-phase column chromatography on octadecyl silica gel cartridges. The assay is fast, convenient, reproducible, sensitive, and inexpensive. The instrumentation required includes standard laboratory equipment and a liquid scintillation counter. The assay is also useful to determine the activity of intracellular PAF-AH (PAF-AH II), provided that a few modifications are included. The enzymatic activity determined using PAF as the substrate is a direct indication of the ability of plasma samples, purified preparations, and cellular and tissue lysates to hydrolyze short- and medium-chain phospholipids that may or may not harbor oxidized functionalities. In addition, the assay can be used to test the suitability of other phospholipids, including species containing oxidized, long-chain sn-2 fatty acyl groups, as PAF-AH substrates. This versatile assay can be used to accurately determine PAF-AH activity in biological samples and preliminarily assess affinity and efficiency of the hydrolysis of potential substrates present in complex mixtures.
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Affiliation(s)
- Diana M. Stafforini
- Huntsman Cancer Institute and Department of Internal Medicine, University of Utah, Salt Lake City, Utah 84112, USA
- To whom correspondence should be addressed: Huntsman Cancer Institute, University of Utah, 2000 Circle of Hope (Suite 3364), Salt Lake City, UT 84112-5550, Tel.: 801-585-3402, Fax: 801-585-0101,
| | - Thomas M. McIntyre
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio 44195, USA
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Sirangelo I, Irace G, Balestrieri ML. Amyloid toxicity and platelet-activating factor signaling. J Cell Physiol 2013; 228:1143-8. [DOI: 10.1002/jcp.24284] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 11/07/2012] [Indexed: 01/08/2023]
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Hirashima Y, Doshi M, Hayashi N, Endo S, Akazawa Y, Shichiri M, Yoshida Y. Plasma platelet-activating factor-acetyl hydrolase activity and the levels of free forms of biomarker of lipid peroxidation in cerebrospinal fluid of patients with aneurysmal subarachnoid hemorrhage. Neurosurgery 2012; 70:602-9. [PMID: 21866060 DOI: 10.1227/neu.0b013e3182333c69] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Free radicals and lipid peroxidation are thought to be related to the vasospasm generation after subarachnoid hemorrhage (SAH). Plasma platelet-activating factor-acetyl hydrolase (PAF-AH) degrades phospholipids with an oxidatively modified fatty acyl chain. OBJECTIVE To compare plasma PAF-AH activity and free forms of biomarker of lipid peroxidation in cerebrospinal fluid (CSF) between patients with and without symptomatic vasospasm (SVS) after SAH. METHODS The identification of PAF-AH in CSF was performed by Western blotting. The genotype at position 279 of the plasma PAF-AH gene was determined. The activities of PAF-AH and the levels of free 8-iso-prostaglandin F2α (free isoPs), free hydroxyoctadecadienoic acid (free HODE), and free hydroxyeicosatetraenoic acid (free HETE) in CSF were measured. RESULTS The PAF-AH in CSF was confirmed to be only the plasma type. The genotype of the plasma PAF-AH was not different between patients with and without SVS. Free isoPs, free HODE, and free HETE showed higher values in patients without SVS in 0 to 4 days and 5 to 9 days after SAH. The PAF-AH activity also was higher in patients without SVS in 0 to 4 days and 5 to 9 days after SAH. The associations between PAF-AH activity and free isoPs, and between PAF-AH activity and free HODE were significant. CONCLUSION Oxidized lipids of lipoproteins and blood cell membranes produced by reactive oxygen species in CSF when SAH occurs may be the main source of lipid peroxidation. Plasma PAF-AH can hydrolyze oxidized phospholipids, and may attenuate the spreading of lipid peroxidation and participate in defense mechanisms against vasospasm after SAH.
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Affiliation(s)
- Yutaka Hirashima
- Physiological Chemistry, Faculty of Pharmaceutical Sciences, Teikyo University, Midori-ku, Sagamihara-shi, Kanagawa, Japan.
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Nitoda E, Moschos MM, Mavragani CP, Koutsilieris M. Ocular actions of platelet-activating factor: clinical implications. Expert Opin Ther Targets 2012; 16:1027-39. [DOI: 10.1517/14728222.2012.712961] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Zheng GH, Xiong SQ, Mei LJ, Chen HY, Wang T, Chu JF. Elevated Plasma Platelet Activating Factor, Platelet Activating Factor Acetylhydrolase Levels and Risk of Coronary Heart Disease or Blood Stasis Syndrome of Coronary Heart Disease in Chinese: A Case Control Study. Inflammation 2012; 35:1419-28. [DOI: 10.1007/s10753-012-9455-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Abstract
Phospholipids are present in all living organisms. They are a major component of all biological membranes, along with glycolipids and cholesterol. Enzymes aimed at cleaving the various bonds in phospholipids, namely phospholipases, are consequently widespread in nature, playing very diverse roles from aggression in snake venom to signal transduction, lipid mediators production, and digestion in humans. Although all phospholipases target phospholipids as substrates, they vary in the site of action on the phospholipids molecules, physiological function, mode of action, and their regulation. Significant studies on phospholipases characterization, physiological role, and industrial potential have been conducted worldwide. Some of them have been directed for biotechnological advances, such as gene discovery and functional enhancement by protein engineering. Others reported phospholipases as virulence factors and major causes of pathophysiological effects. In this introductory chapter, we provide brief details of different phospholipases.
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Affiliation(s)
- Ahmed Aloulou
- National School of Engineers of Sfax, University of Sfax, Sfax, Tunisia.
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Silva IT, Mello APQ, Damasceno NRT. Antioxidant and inflammatory aspects of lipoprotein-associated phospholipase A₂ (Lp-PLA₂): a review. Lipids Health Dis 2011; 10:170. [PMID: 21955667 PMCID: PMC3204246 DOI: 10.1186/1476-511x-10-170] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 09/28/2011] [Indexed: 12/11/2022] Open
Abstract
The association of cardiovascular events with Lp-PLA2 has been studied continuously today. The enzyme has been strongly associated with several cardiovascular risk markers and events. Its discovery was directly related to the hydrolysis of the platelet-activating factor and oxidized phospholipids, which are considered protective functions. However, the hydrolysis of bioactive lipids generates lysophospholipids, compounds that have a pro-inflammatory function. Therefore, the evaluation of the distribution of Lp-PLA2 in the lipid fractions emphasized the dual role of the enzyme in the inflammatory process, since the HDL-Lp-PLA2 enzyme contributes to the reduction of atherosclerosis, while LDL-Lp-PLA2 stimulates this process. Recently, it has been verified that diet components and drugs can influence the enzyme activity and concentration. Thus, the effects of these treatments on Lp-PLA2 may represent a new kind of prevention of cardiovascular disease. Therefore, the association of the enzyme with the traditional assessment of cardiovascular risk may help to predict more accurately these diseases.
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Affiliation(s)
- Isis T Silva
- Departamento de Nutrição, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil
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31
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Thévenin AF, Monillas ES, Winget JM, Czymmek K, Bahnson BJ. Trafficking of platelet-activating factor acetylhydrolase type II in response to oxidative stress. Biochemistry 2011; 50:8417-26. [PMID: 21882811 DOI: 10.1021/bi200802w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Platelet-activating factor acetylhydrolase type II (PAFAH-II) is an intracellular phospholipase A(2) enzyme that hydrolyzes platelet-activating factor and oxidatively fragmented phospholipids. This N-terminally myristoylated protein becomes associated with cytoplasm-facing cell membranes under oxidative stress. The structural requirements for binding of PAFAH-II to membranes in response to oxidative stress are unknown. To begin elucidating the mechanism of trafficking and stress response, we constructed a homology model of PAFAH-II. From the predicted membrane orientation of PAFAH-II, the N-terminal myristoyl group and a hydrophobic patch are hypothesized to be involved in membrane binding. Localization studies of human PAFAH-II in HEK293 cells indicated that an unmyristoylated mutant remained cytoplasmic under stressed and unstressed conditions. The myristoylated wild-type enzyme was partially localized to the cytoplasmic membranes prior to stress and became more localized to these membranes upon stress. A triple mutation of three hydrophobic patch residues of the membrane binding region likewise did not localize to membranes following stress. These results indicate that both the myristoyl group and the hydrophobic patch are essential for proper trafficking of the enzyme to the membranes following oxidative stress. Additionally, colocalization studies using organelle-specific proteins demonstrate that PAFAH-II is transported to the membranes of both the endoplasmic reticulum and Golgi apparatus.
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Affiliation(s)
- Anastasia F Thévenin
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
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The Role of Proteomics in the Diagnosis and Treatment of Women's Cancers: Current Trends in Technology and Future Opportunities. INTERNATIONAL JOURNAL OF PROTEOMICS 2011; 2011. [PMID: 21886869 PMCID: PMC3163496 DOI: 10.1155/2011/373584] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Technological and scientific innovations over the last decade have greatly contributed to improved diagnostics, predictive models, and prognosis among cancers affecting women. In fact, an explosion of information in these areas has almost assured future generations that outcomes in cancer will continue to improve. Herein we discuss the current status of breast, cervical, and ovarian cancers as it relates to screening, disease diagnosis, and treatment options. Among the differences in these cancers, it is striking that breast cancer has multiple predictive tests based upon tumor biomarkers and sophisticated, individualized options for prescription therapeutics while ovarian cancer lacks these tools. In addition, cervical cancer leads the way in innovative, cancer-preventative vaccines and multiple screening options to prevent disease progression. For each of these malignancies, emerging proteomic technologies based upon mass spectrometry, stable isotope labeling with amino acids, high-throughput ELISA, tissue or protein microarray techniques, and click chemistry in the pursuit of activity-based profiling can pioneer the next generation of discovery. We will discuss six of the latest techniques to understand proteomics in cancer and highlight research utilizing these techniques with the goal of improvement in the management of women's cancers.
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Fang HY, Chen SB, Guo DJ, Pan SY, Yu ZL. Proteomic identification of differentially expressed proteins in curcumin-treated MCF-7 cells. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2011; 18:697-703. [PMID: 21239154 DOI: 10.1016/j.phymed.2010.11.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 09/22/2010] [Accepted: 11/22/2010] [Indexed: 05/30/2023]
Abstract
Curcumin (CM), a well-known dietary pigment derived from Curcuma longa L., possess anticancer activities against a variety of tumors including human breast carcinoma. In combination with docetaxel, CM has been used in breast cancer management in the clinic. In order to explore the possible mechanism of anticancer activity of CM, in the present study, we aimed to identify proteins involved in the anticancer activity of CM in human breast cancer cell line MCF-7 using the two-dimensional electrophoresis (2-DE)-based proteomic analysis. MCF-7 cells were cultured at 37°C in an atmosphere of 5.0% CO(2). All the following experiments were repeated three times. Cell viability assay showed that after a 48-h incubation CM dose-dependently inhibited cell growth with an IC(50) value of 47.42 μM. Treatment of CM at 47.42 μM for 48 h induced apoptosis as determined by nuclear morphologic changes of Hoechst stained cells and flow cytometric analysis of Annexin V-FITC/PI stained cells. Proteomic analysis identified 12 differentially expressed proteins which contributed to multiple functional activities such as DNA transcription, mRNA splicing and translation, amino acid synthesis, protein synthesis, folding and degradation, lipid metabolism, glycolysis, and cell motility. Among them 7 proteins were up-regulated and 5 down-regulated. The up-regulated ones were verified by quantitative real-time PCR. The down-regulated proteins, TDP-43, SF2/ASF and eIF3i, as well as up-regulated ones, 3-PGDH, ERP29, and platelet-activating factor acetylhydrolase IB subunit beta positively contribute to the anticancer activity of CM in MCF-7 cells. These molecules are implicated in the bioactivities of CM for the first time. The findings of this study would shed new insights for systematically understanding the mechanisms of CM in breast cancer intervention.
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Affiliation(s)
- H Y Fang
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Bechler ME, Doody AM, Ha KD, Judson BL, Chen I, Brown WJ. The phospholipase A₂ enzyme complex PAFAH Ib mediates endosomal membrane tubule formation and trafficking. Mol Biol Cell 2011; 22:2348-59. [PMID: 21593204 PMCID: PMC3128536 DOI: 10.1091/mbc.e09-12-1064] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
For the first time, a cytoplasmic phospholipase A2 enzyme, platelet-activating factor acetylhydrolase (I)b, is described that is directly involved in the formation of membrane
tubules from endosomes and trafficking through the endocytic recycling pathway. Previous studies have shown that membrane tubule–mediated export from endosomal compartments requires a cytoplasmic phospholipase A2 (PLA2) activity. Here we report that the cytoplasmic PLA2 enzyme complex platelet-activating factor acetylhydrolase (PAFAH) Ib, which consists of α1, α2, and LIS1 subunits, regulates the distribution and function of endosomes. The catalytic subunits α1 and α2 are located on early-sorting endosomes and the central endocytic recycling compartment (ERC) and their overexpression, but not overexpression of their catalytically inactive counterparts, induced endosome membrane tubules. In addition, overexpression α1 and α2 altered normal endocytic trafficking; transferrin was recycled back to the plasma membrane directly from peripheral early-sorting endosomes instead of making an intermediate stop in the ERC. Consistent with these results, small interfering RNA–mediated knockdown of α1 and α2 significantly inhibited the formation of endosome membrane tubules and delayed the recycling of transferrin. In addition, the results agree with previous reports that PAFAH Ib α1 and α2 expression levels affect the distribution of endosomes within the cell through interactions with the dynein regulator LIS1. These studies show that PAFAH Ib regulates endocytic membrane trafficking through novel mechanisms involving both PLA2 activity and LIS1-dependent dynein function.
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Affiliation(s)
- Marie E Bechler
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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35
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Affiliation(s)
- Makoto MURAKAMI
- Biomembrane Signaling Project, The Tokyo Metropolitan Institute of Medical Science
- Department of Health Chemistry, School of Pharmaceutical Science, Showa University
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36
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Murakami M, Taketomi Y, Miki Y, Sato H, Hirabayashi T, Yamamoto K. Recent progress in phospholipase A₂ research: from cells to animals to humans. Prog Lipid Res 2010; 50:152-92. [PMID: 21185866 DOI: 10.1016/j.plipres.2010.12.001] [Citation(s) in RCA: 368] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mammalian genomes encode genes for more than 30 phospholipase A₂s (PLA₂s) or related enzymes, which are subdivided into several classes including low-molecular-weight secreted PLA₂s (sPLA₂s), Ca²+-dependent cytosolic PLA₂s (cPLA₂s), Ca²+-independent PLA₂s (iPLA₂s), platelet-activating factor acetylhydrolases (PAF-AHs), lysosomal PLA₂s, and a recently identified adipose-specific PLA. Of these, the intracellular cPLA₂ and iPLA₂ families and the extracellular sPLA₂ family are recognized as the "big three". From a general viewpoint, cPLA₂α (the prototypic cPLA₂ plays a major role in the initiation of arachidonic acid metabolism, the iPLA₂ family contributes to membrane homeostasis and energy metabolism, and the sPLA₂ family affects various biological events by modulating the extracellular phospholipid milieus. The cPLA₂ family evolved along with eicosanoid receptors when vertebrates first appeared, whereas the diverse branching of the iPLA₂ and sPLA₂ families during earlier eukaryote development suggests that they play fundamental roles in life-related processes. During the past decade, data concerning the unexplored roles of various PLA₂ enzymes in pathophysiology have emerged on the basis of studies using knockout and transgenic mice, the use of specific inhibitors, and information obtained from analysis of human diseases caused by mutations in PLA₂ genes. This review focuses on current understanding of the emerging biological functions of PLA₂s and related enzymes.
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Affiliation(s)
- Makoto Murakami
- Lipid Metabolism Project, The Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
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Lu J, Pierce M, Franklin A, Jilling T, Stafforini DM, Caplan M. Dual roles of endogenous platelet-activating factor acetylhydrolase in a murine model of necrotizing enterocolitis. Pediatr Res 2010; 68:225-30. [PMID: 20531249 PMCID: PMC2921952 DOI: 10.1203/pdr.0b013e3181eb2efe] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Human preterm infants with necrotizing enterocolitis (NEC) have increased circulating and luminal levels of platelet-activating factor (PAF) and decreased serum PAF-acetylhydrolase (PAF-AH), the enzyme that inactivates PAF. Formula supplemented with recombinant PAF-AH decreases NEC in a neonatal rat model. We hypothesized that endogenous PAF-AH contributes to neonatal intestinal homeostasis and therefore developed PAF-AH mice using standard approaches to study the role of this enzyme in the neonatal NEC model. After exposure to a well-established NEC model, intestinal tissues were evaluated for histology, proinflammatory cytokine mRNA synthesis, and death using standard techniques. We found that mortality rates were significantly lower in PAF-AH pups compared with wild-type controls before 24 h of life but surviving PAF-AH animals were more susceptible to NEC development compared with wild-type controls. Increased NEC incidence was associated with prominent inflammation characterized by elevated intestinal mRNA expression of sPLA2, inducible NOS, and CXCL1. In conclusion, the data support a protective role for endogenous PAF-AH in the development of NEC, and because preterm neonates have endogenous PAF-AH deficiency, this may place them at increased risk for disease.
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Affiliation(s)
- Jing Lu
- Department of Pediatrics, Pritzker School of Medicine, University of Chicago, Evanston, IL 60201, USA
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38
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Murakami M, Taketomi Y, Girard C, Yamamoto K, Lambeau G. Emerging roles of secreted phospholipase A2 enzymes: Lessons from transgenic and knockout mice. Biochimie 2010; 92:561-82. [PMID: 20347923 DOI: 10.1016/j.biochi.2010.03.015] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 03/18/2010] [Indexed: 11/15/2022]
Abstract
Among the emerging phospholipase A(2) (PLA(2)) superfamily, the secreted PLA(2) (sPLA(2)) family consists of low-molecular-mass, Ca(2+)-requiring extracellular enzymes with a His-Asp catalytic dyad. To date, more than 10 sPLA(2) enzymes have been identified in mammals. Individual sPLA(2)s exhibit unique tissue and cellular localizations and enzymatic properties, suggesting their distinct pathophysiological roles. Despite numerous enzymatic and cell biological studies on this enzyme family in the past two decades, their precise in vivo functions still remain largely obscure. Recent studies using transgenic and knockout mice for several sPLA(2) enzymes, in combination with lipidomics approaches, have opened new insights into their distinct contributions to various biological events such as food digestion, host defense, inflammation, asthma and atherosclerosis. In this article, we overview the latest understanding of the pathophysiological functions of individual sPLA(2) isoforms fueled by studies employing transgenic and knockout mice for several sPLA(2)s.
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Affiliation(s)
- Makoto Murakami
- Biomembrane Signaling Project, The Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
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39
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Pietro ES, Capestrano M, Polishchuk EV, DiPentima A, Trucco A, Zizza P, Mariggiò S, Pulvirenti T, Sallese M, Tete S, Mironov AA, Leslie CC, Corda D, Luini A, Polishchuk RS. Group IV phospholipase A(2)alpha controls the formation of inter-cisternal continuities involved in intra-Golgi transport. PLoS Biol 2009; 7:e1000194. [PMID: 19753100 PMCID: PMC2732982 DOI: 10.1371/journal.pbio.1000194] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Accepted: 07/31/2009] [Indexed: 11/18/2022] Open
Abstract
The organization of intra-Golgi trafficking and the nature of the transport intermediates involved (e.g., vesicles, tubules, or tubular continuities) remain incompletely understood. It was recently shown that successive cisternae in the Golgi stack are interconnected by membrane tubules that form during the arrival of transport carriers from the endoplasmic reticulum. Here, we examine the mechanisms of generation and the function of these tubules. In principle, tubule formation might depend on several protein- and/or lipid-based mechanisms. Among the latter, we have studied the phospholipase A(2) (PLA(2))-mediated generation of wedge-shaped lysolipids, with the resulting local positive membrane curvature. We show that the arrival of cargo at the Golgi complex induces the recruitment of Group IVA Ca(2+)-dependent, cytosolic PLA(2) (cPLA(2)alpha) onto the Golgi complex itself, and that this cPLA(2)alpha is required for the formation of the traffic-dependent intercisternal tubules and for intra-Golgi transport. In contrast, silencing of cPLA(2)alpha has no inhibitory effects on peri-Golgi vesicles. These findings identify cPLA(2)alpha as the first component of the machinery that is responsible for the formation of intercisternal tubular continuities and support a role for these continuities in transport through the Golgi complex.
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Affiliation(s)
- Enrica San Pietro
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Chieti, Italy
| | | | - Elena V. Polishchuk
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Chieti, Italy
| | - Alessio DiPentima
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Chieti, Italy
| | - Alvar Trucco
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Chieti, Italy
| | - Pasquale Zizza
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Chieti, Italy
| | - Stefania Mariggiò
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Chieti, Italy
| | - Teodoro Pulvirenti
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Chieti, Italy
| | - Michele Sallese
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Chieti, Italy
| | - Stefano Tete
- Department of Oral Sciences, University “G. D'Annunzio”, Chieti, Italy
| | - Alexander A. Mironov
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Chieti, Italy
| | - Christina C. Leslie
- Department of Pediatrics, National Jewish Medical and Research Center, Denver, Colorado, United States of America
| | - Daniela Corda
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Chieti, Italy
| | - Alberto Luini
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Chieti, Italy
- Telethon Institute of Genetics and Medicine, Naples, Italy
- * E-mail: (AL); (RSP)
| | - Roman S. Polishchuk
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Chieti, Italy
- Telethon Institute of Genetics and Medicine, Naples, Italy
- * E-mail: (AL); (RSP)
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Kitsiouli E, Nakos G, Lekka ME. Phospholipase A2 subclasses in acute respiratory distress syndrome. Biochim Biophys Acta Mol Basis Dis 2009; 1792:941-53. [PMID: 19577642 DOI: 10.1016/j.bbadis.2009.06.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 06/25/2009] [Accepted: 06/25/2009] [Indexed: 01/12/2023]
Abstract
Phospholipases A2 (PLA2) catalyse the cleavage of fatty acids esterified at the sn-2 position of glycerophospholipids. In acute lung injury-acute respiratory distress syndrome (ALI-ARDS) several distinct isoenzymes appear in lung cells and fluid. Some are capable to trigger molecular events leading to enhanced inflammation and lung damage and others have a role in lung surfactant recycling preserving lung function: Secreted forms (groups sPLA2-IIA, -V, -X) can directly hydrolyze surfactant phospholipids. Cytosolic PLA2 (cPLA2-IVA) requiring Ca2+ has a preference for arachidonate, the precursor of eicosanoids which participate in the inflammatory response in the lung. Ca(2+)-independent intracellular PLA2s (iPLA2) take part in surfactant phospholipids turnover within alveolar cells. Acidic Ca(2+)-independent PLA2 (aiPLA2), of lysosomal origin, has additionally antioxidant properties, (peroxiredoxin VI activity), and participates in the formation of dipalmitoyl-phosphatidylcholine in lung surfactant. PAF-AH degrades PAF, a potent mediator of inflammation, and oxidatively fragmented phospholipids but also leads to toxic metabolites. Therefore, the regulation of PLA2 isoforms could be a valuable approach for ARDS treatment.
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Affiliation(s)
- Eirini Kitsiouli
- Department of Biological Applications and Technologies, School of Sciences and Technologies, University of Ioannina, Greece
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41
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Epstein TM, Samanta U, Kirby SD, Cerasoli DM, Bahnson BJ. Crystal structures of brain group-VIII phospholipase A2 in nonaged complexes with the organophosphorus nerve agents soman and sarin. Biochemistry 2009; 48:3425-35. [PMID: 19271773 DOI: 10.1021/bi8023527] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Insecticide and nerve agent organophosphorus (OP) compounds are potent inhibitors of the serine hydrolase superfamily of enzymes. Nerve agents, such as sarin, soman, tabun, and VX exert their toxicity by inhibiting human acetycholinesterase at nerve synapses. Following the initial phosphonylation of the active site serine, the enzyme may reactivate spontaneously or through reaction with an appropriate nucleophilic oxime. Alternatively, the enzyme-nerve agent complex can undergo a secondary process, called "aging", which dealkylates the nerve agent adduct and results in a product that is highly resistant to reactivation by any known means. Here we report the structures of paraoxon, soman, and sarin complexes of group-VIII phospholipase A2 from bovine brain. In each case, the crystal structures indicate a nonaged adduct; a stereoselective preference for binding of the P(S)C(S) isomer of soman and the P(S) isomer of sarin was also noted. The stability of the nonaged complexes was corroborated by trypsin digest and electrospray ionization mass spectrometry, which indicates nonaged complexes are formed with diisopropylfluorophosphate, soman, and sarin. The P(S) stereoselectivity for reaction with sarin was confirmed by reaction of racemic sarin, followed by gas chromatography/mass spectrometry using a chiral column to separate and quantitate each stereoisomer. The P(S) stereoisomers of soman and sarin are known to be the more toxic stereoisomers, as they react preferentially to inhibit human acetylcholinesterase. The results obtained for nonaged complexes of group-VIII phospholipase A2 are compared to those obtained for other serine hydrolases and discussed to partly explain determinants of OP aging. Furthermore, structural insights can now be exploited to engineer variant versions of this enzyme with enhanced nerve agent binding and hydrolysis functions.
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Affiliation(s)
- Todd M Epstein
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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42
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Samanta U, Wilder C, Bahnson BJ. Crystallization and preliminary X-ray crystallographic analysis of human plasma platelet activating factor acetylhydrolase. Protein Pept Lett 2009; 16:97-100. [PMID: 19149681 DOI: 10.2174/092986609787049321] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The plasma form of the human enzyme platelet activating factor acetylhydrolase (PAF-AH) has been crystallized, and X-ray diffraction data were collected at a synchrotron source to a resolution of 1.47 A. The crystals belong to space group C2, with unit cell parameters of a = 116.18, b = 83.06, c = 96.71 A, and beta= 115.09 degrees and two molecules in the asymmetric unit. PAF-AH functions as a general anti-inflammatory scavenger by reducing the levels of the signaling molecule PAF. Additionally, the LDL bound enzyme has been linked to atherosclerosis due to its hydrolytic activities of pro-inflammatory agents, such as sn-2 oxidatively fragmented phospholipids.
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Affiliation(s)
- Uttamkumar Samanta
- Department of Chemistry & Biochemistry, University of Delaware, Newark, DE 19716, USA
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43
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Ali M, Madjid M. Lipoprotein-associated phospholipase A2: a cardiovascular risk predictor and a potential therapeutic target. Future Cardiol 2009; 5:159-73. [DOI: 10.2217/14796678.5.2.159] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Lipoprotein-associated phospholipase A2 (Lp-PLA2), present in the circulation and in atherosclerotic plaque, is an inflammatory marker with potential use as a predictor of cardiovascular risk and as a therapeutic target. Although Lp-PLA2 is associated with both LDL and HDL, it is important to determine whether Lp-PLA2 has a predominantly pro- or anti-atherogenic effect. Increasing evidence suggests a proatherogenic role for Lp-PLA2. ©iEpidemiologic and clinical evidence suggests Lp-PLA2 is an independent predictor of risk and may be superior to other inflammatory markers owing to its specificity and minimal biovariation. Lp-PLA2 inhibitors currently being investigated in clinical trials are promising novel anti-inflammatory agents with a specificity for the vascular bed and a potential for decreasing plaque vulnerability.
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Affiliation(s)
- Muzammil Ali
- Texas Heart Institute, 6770 Bertner Ave, MC 2-255, Houston, TX 77030, USA
| | - Mohammad Madjid
- Texas Heart Institute at St Luke’s Episcopal Hospital, The University of Texas Health Science Center at Houston, Houston, TX, USA
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44
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Samanta U, Bahnson BJ. Crystal structure of human plasma platelet-activating factor acetylhydrolase: structural implication to lipoprotein binding and catalysis. J Biol Chem 2008; 283:31617-24. [PMID: 18784071 PMCID: PMC2581546 DOI: 10.1074/jbc.m804750200] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 08/28/2008] [Indexed: 12/15/2022] Open
Abstract
Human plasma platelet-activating factor (PAF) acetylhydrolase functions by reducing PAF levels as a general anti-inflammatory scavenger and is linked to anaphylactic shock, asthma, and allergic reactions. The enzyme has also been implicated in hydrolytic activities of other pro-inflammatory agents, such as sn-2 oxidatively fragmented phospholipids. This plasma enzyme is tightly bound to low and high density lipoprotein particles and is also referred to as lipoprotein-associated phospholipase A2. The crystal structure of this enzyme has been solved from x-ray diffraction data collected to a resolution of 1.5 angstroms. It has a classic lipase alpha/beta-hydrolase fold, and it contains a catalytic triad of Ser273, His351, and Asp296. Two clusters of hydrophobic residues define the probable interface-binding region, and a prediction is given of how the enzyme is bound to lipoproteins. Additionally, an acidic patch of 10 carboxylate residues and a neighboring basic patch of three residues are suggested to play a role in high density lipoprotein/low density lipoprotein partitioning. A crystal structure is also presented of PAF acetylhydrolase reacted with the organophosphate compound paraoxon via its active site Ser273. The resulting diethyl phosphoryl complex was used to model the tetrahedral intermediate of the substrate PAF to the active site. The model of interface binding begins to explain the known specificity of lipoprotein-bound substrates and how the active site can be both close to the hydrophobic-hydrophilic interface and at the same time be accessible to the aqueous phase.
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Affiliation(s)
- Uttamkumar Samanta
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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Stafforini DM. Biology of platelet-activating factor acetylhydrolase (PAF-AH, lipoprotein associated phospholipase A2). Cardiovasc Drugs Ther 2008; 23:73-83. [PMID: 18949548 DOI: 10.1007/s10557-008-6133-8] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Accepted: 08/06/2008] [Indexed: 12/26/2022]
Abstract
INTRODUCTION This article is focused on platelet-activating factor acetylhydrolase (PAF-AH), a lipoprotein bound, calcium-independent phospholipase A(2) activity also referred to as lipoprotein-associated phospholipase A(2) or PLA(2)G7. PAF-AH catalyzes the removal of the acyl group at the sn-2 position of PAF and truncated phospholipids generated in settings of inflammation and oxidant stress. DISCUSSION Here, I discuss current knowledge related to the structural features of this enzyme, including the molecular basis for association with lipoproteins and susceptibility to oxidative inactivation. The circulating form of PAF-AH is constitutively active and its expression is upregulated by mediators of inflammation at the transcriptional level. This mechanism is likely responsible for the observed up-regulation of PAF-AH during atherosclerosis and suggests that increased expression of this enzyme is a physiological response to inflammatory stimuli. Administration of recombinant forms of PAF-AH attenuate inflammation in a variety of experimental models. Conversely, genetic deficiency of PAF-AH in defined human populations increases the severity of atherosclerosis and other syndromes. Recent advances pointing to an interplay among oxidized phospholipid substrates, Lp(a), and PAF-AH could hold the key to a number of unanswered questions.
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Affiliation(s)
- Diana M Stafforini
- Huntsman Cancer Institute and Department of Internal Medicine, University of Utah, 2000 Circle of Hope, Suite 3364, Salt Lake City, UT 84112-5550, USA.
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Multiple roles of phospholipase A2 during lung infection and inflammation. Infect Immun 2008; 76:2259-72. [PMID: 18411286 DOI: 10.1128/iai.00059-08] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Scott BT, Olson N, Long GL, Bovill EG. Novel isoforms of intracellular platelet activating factor acetylhydrolase (PAFAH1b2) in human testis; encoded by alternatively spliced mRNAs. Prostaglandins Other Lipid Mediat 2007; 85:69-80. [PMID: 18155631 DOI: 10.1016/j.prostaglandins.2007.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Revised: 08/29/2007] [Accepted: 10/26/2007] [Indexed: 11/19/2022]
Abstract
Platelet activating factor acetylhydrolase (paf-ah), a potent regulator of platelet activating factor activity, plays an important role in various physiological and pathophysiological functions including development, reproduction, inflammation, hemostasis, and apoptosis. Intracellular paf-ah (paf-ah-Ib) is composed of a regulatory subunit, Pafah1b1, and two highly conserved but non-identical catalytic subunits, Pafah1b2 and Pafah1b3. The present study identifies new splice variants of the Pafah1b2 gene transcript. The splice variants retain exons 1-5 and replace exon 6 with alternative exons derived from genomic sequence 3' to exon 6. Splice variants encode two proteins with different novel carboxy termini. One of the isoforms is expressed exclusively in testis. These new isoforms of pafah1b2 retain the ability to form higher order complexes while replacing known key catalytic residues, which raises the possibility that they may alter the subunit composition and catalytic function of paf-ah-Ib.
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Affiliation(s)
- Bruce T Scott
- Department of Pathology, University of Vermont, Burlington, VT, USA
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Role of platelet activating factor in pathogenesis of acute respiratory distress syndrome. Chin Med J (Engl) 2007. [DOI: 10.1097/00029330-200710020-00022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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Shindou H, Hishikawa D, Nakanishi H, Harayama T, Ishii S, Taguchi R, Shimizu T. A Single Enzyme Catalyzes Both Platelet-activating Factor Production and Membrane Biogenesis of Inflammatory Cells. J Biol Chem 2007; 282:6532-9. [PMID: 17182612 DOI: 10.1074/jbc.m609641200] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Platelet-activating factor (PAF) is a potent proinflammatory lipid mediator eliciting a variety of cellular functions. Lipid mediators, including PAF are produced from membrane phospholipids by enzymatic cascades. Although a G protein-coupled PAF receptor and degradation enzymes have been cloned and characterized, the PAF biosynthetic enzyme, aceyl-CoA:lyso-PAF acetyltransferase, has not been identified. Here, we cloned lyso-PAF acetyltransferase, which is critical in stimulus-dependent formation of PAF. The enzyme is a 60-kDa microsomal protein with three putative membrane-spanning domains. The enzyme was induced by bacterial endotoxin (lipopolysaccharide), which was suppressed by dexamethasone treatment. Surprisingly, the enzyme catalyzed not only biosynthesis of PAF from lyso-PAF but also incorporation of arachidonoyl-CoA to produce PAF precursor membrane glycerophospholipids (lysophosphatidylcholine acyltransferase activity). Under resting conditions, the enzyme prefers arachidonoyl-CoA and contributes to membrane biogenesis. Upon acute inflammatory stimulation with lipopolysaccharide, the activated enzyme utilizes acetyl-CoA more efficiently and produces PAF. Thus, our findings provide a novel concept that a single enzyme catalyzes membrane biogenesis of inflammatory cells while producing a prophlogistic mediator in response to external stimuli.
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Affiliation(s)
- Hideo Shindou
- Department of Biochemistry and Molecular Biology, University of Tokyo, Hongo, Tokyo, Japan
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Phillis JW, Horrocks LA, Farooqui AA. Cyclooxygenases, lipoxygenases, and epoxygenases in CNS: Their role and involvement in neurological disorders. ACTA ACUST UNITED AC 2006; 52:201-43. [PMID: 16647138 DOI: 10.1016/j.brainresrev.2006.02.002] [Citation(s) in RCA: 266] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Revised: 02/23/2006] [Accepted: 02/24/2006] [Indexed: 01/01/2023]
Abstract
Three enzyme systems, cyclooxygenases that generate prostaglandins, lipoxygenases that form hydroxy derivatives and leukotrienes, and epoxygenases that give rise to epoxyeicosatrienoic products, metabolize arachidonic acid after its release from neural membrane phospholipids by the action of phospholipase A(2). Lysophospholipids, the other products of phospholipase A(2) reactions, are either reacylated or metabolized to platelet-activating factor. Under normal conditions, these metabolites play important roles in synaptic function, cerebral blood flow regulation, apoptosis, angiogenesis, and gene expression. Increased activities of cyclooxygenases, lipoxygenases, and epoxygenases under pathological situations such as ischemia, epilepsy, Alzheimer's disease, Parkinson disease, amyotrophic lateral sclerosis, and Creutzfeldt-Jakob disease produce neuroinflammation involving vasodilation and vasoconstriction, platelet aggregation, leukocyte chemotaxis and release of cytokines, and oxidative stress. These are closely associated with the neural cell injury which occurs in these neurological conditions. The metabolic products of docosahexaenoic acid, through these enzymes, generate a new class of lipid mediators, namely docosatrienes and resolvins. These metabolites antagonize the effect of metabolites derived from arachidonic acid. Recent studies provide insight into how these arachidonic acid metabolites interact with each other and other bioactive mediators such as platelet-activating factor, endocannabinoids, and docosatrienes under normal and pathological conditions. Here, we review present knowledge of the functions of cyclooxygenases, lipoxygenases, and epoxygenases in brain and their association with neurodegenerative diseases.
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Affiliation(s)
- John W Phillis
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA.
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