1
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Köberlin MS, Fan Y, Liu C, Chung M, Pinto AFM, Jackson PK, Saghatelian A, Meyer T. A fast-acting lipid checkpoint in G1 prevents mitotic defects. Nat Commun 2024; 15:2441. [PMID: 38499565 PMCID: PMC10948896 DOI: 10.1038/s41467-024-46696-9] [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: 07/24/2023] [Accepted: 03/06/2024] [Indexed: 03/20/2024] Open
Abstract
Lipid synthesis increases during the cell cycle to ensure sufficient membrane mass, but how insufficient synthesis restricts cell-cycle entry is not understood. Here, we identify a lipid checkpoint in G1 phase of the mammalian cell cycle by using live single-cell imaging, lipidome, and transcriptome analysis of a non-transformed cell. We show that synthesis of fatty acids in G1 not only increases lipid mass but extensively shifts the lipid composition to unsaturated phospholipids and neutral lipids. Strikingly, acute lowering of lipid synthesis rapidly activates the PERK/ATF4 endoplasmic reticulum (ER) stress pathway that blocks cell-cycle entry by increasing p21 levels, decreasing Cyclin D levels, and suppressing Retinoblastoma protein phosphorylation. Together, our study identifies a rapid anticipatory ER lipid checkpoint in G1 that prevents cells from starting the cell cycle as long as lipid synthesis is low, thereby preventing mitotic defects, which are triggered by low lipid synthesis much later in mitosis.
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Affiliation(s)
- Marielle S Köberlin
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Baxter Laboratory, Department of Microbiology & Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
| | - Yilin Fan
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Department of Pathology and Center for Cancer Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - Chad Liu
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Chan Zuckerberg Biohub, San Francisco, CA, 94111, USA
| | - Mingyu Chung
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Antonio F M Pinto
- Clayton Foundation Laboratories for Peptide Biology and Mass Spectrometry Core, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Peter K Jackson
- Baxter Laboratory, Department of Microbiology & Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Alan Saghatelian
- Clayton Foundation Laboratories for Peptide Biology and Mass Spectrometry Core, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Tobias Meyer
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Department of Cell and Developmental Biology, Weill Cornell Medicine, New York, NY, 10065, USA.
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2
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Yan B, Yuan S, Cao J, Fung K, Lai PM, Yin F, Sze KH, Qin Z, Xie Y, Ye ZW, Yuen TTT, Chik KKH, Tsang JOL, Zou Z, Chan CCY, Luo C, Cai JP, Chan KH, Chung TWH, Tam AR, Chu H, Jin DY, Hung IFN, Yuen KY, Kao RYT, Chan JFW. Phosphatidic acid phosphatase 1 impairs SARS-CoV-2 replication by affecting the glycerophospholipid metabolism pathway. Int J Biol Sci 2022; 18:4744-4755. [PMID: 35874954 PMCID: PMC9305268 DOI: 10.7150/ijbs.73057] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 05/27/2022] [Indexed: 11/08/2022] Open
Abstract
Viruses exploit the host lipid metabolism machinery to achieve efficient replication. We herein characterize the lipids profile reprogramming in vitro and in vivo using liquid chromatography-mass spectrometry-based untargeted lipidomics. The lipidome of SARS-CoV-2-infected Caco-2 cells was markedly different from that of mock-infected samples, with most of the changes involving downregulation of ceramides. In COVID-19 patients' plasma samples, a total of 54 lipids belonging to 12 lipid classes that were significantly perturbed compared to non-infected control subjects' plasma samples were identified. Among these 12 lipid classes, ether-linked phosphatidylcholines, ether-linked phosphatidylethanolamines, phosphatidylcholines, and ceramides were the four most perturbed. Pathway analysis revealed that the glycerophospholipid, sphingolipid, and ether lipid metabolisms pathway were the most significantly perturbed host pathways. Phosphatidic acid phosphatases (PAP) were involved in all three pathways and PAP-1 deficiency significantly suppressed SARS-CoV-2 replication. siRNA knockdown of LPIN2 and LPIN3 resulted in significant reduction of SARS-CoV-2 load. In summary, these findings characterized the host lipidomic changes upon SARS-CoV-2 infection and identified PAP-1 as a potential target for intervention for COVID-19.
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Affiliation(s)
- Bingpeng Yan
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Shuofeng Yuan
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Jianli Cao
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Kingchun Fung
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Pok-Man Lai
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Feifei Yin
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, Hainan, China.,Academician Workstation of Hainan Province, Hainan Medical University, Haikou, Hainan, China.,Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.,Department of Pathogen Biology, Hainan Medical University, Haikou, Hainan, China
| | - Kong-Hung Sze
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.,Centre for Virology, Vaccinology and Therapeutics, Hong Kong Science and Technology Park, Hong Kong Special Administrative Region, China
| | - Zhenzhi Qin
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Yubin Xie
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Zi-Wei Ye
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Terrence Tsz-Tai Yuen
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Kenn Ka-Heng Chik
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.,Centre for Virology, Vaccinology and Therapeutics, Hong Kong Science and Technology Park, Hong Kong Special Administrative Region, China
| | - Jessica Oi-Ling Tsang
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.,Centre for Virology, Vaccinology and Therapeutics, Hong Kong Science and Technology Park, Hong Kong Special Administrative Region, China
| | - Zijiao Zou
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Chris Chun-Yiu Chan
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Cuiting Luo
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Jian-Piao Cai
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Kwok-Hung Chan
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.,Centre for Virology, Vaccinology and Therapeutics, Hong Kong Science and Technology Park, Hong Kong Special Administrative Region, China
| | - Tom Wai-Hing Chung
- Department of Microbiology, Queen Mary Hospital, Pokfulam, Hong Kong Special Administrative Region, China
| | - Anthony Raymond Tam
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Hin Chu
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.,Centre for Virology, Vaccinology and Therapeutics, Hong Kong Science and Technology Park, Hong Kong Special Administrative Region, China.,Department of Infectious Disease and Microbiology, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Dong-Yan Jin
- Centre for Virology, Vaccinology and Therapeutics, Hong Kong Science and Technology Park, Hong Kong Special Administrative Region, China.,School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.,Guangzhou Laboratory, Guangdong Province, China
| | - Ivan Fan-Ngai Hung
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.,Department of Infectious Disease and Microbiology, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Kwok-Yung Yuen
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.,Academician Workstation of Hainan Province, Hainan Medical University, Haikou, Hainan, China.,Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.,Centre for Virology, Vaccinology and Therapeutics, Hong Kong Science and Technology Park, Hong Kong Special Administrative Region, China.,Department of Microbiology, Queen Mary Hospital, Pokfulam, Hong Kong Special Administrative Region, China.,Department of Infectious Disease and Microbiology, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China.,Guangzhou Laboratory, Guangdong Province, China
| | - Richard Yi-Tsun Kao
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.,Centre for Virology, Vaccinology and Therapeutics, Hong Kong Science and Technology Park, Hong Kong Special Administrative Region, China
| | - Jasper Fuk-Woo Chan
- State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.,Academician Workstation of Hainan Province, Hainan Medical University, Haikou, Hainan, China.,Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.,Centre for Virology, Vaccinology and Therapeutics, Hong Kong Science and Technology Park, Hong Kong Special Administrative Region, China.,Department of Microbiology, Queen Mary Hospital, Pokfulam, Hong Kong Special Administrative Region, China.,Department of Infectious Disease and Microbiology, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China.,Guangzhou Laboratory, Guangdong Province, China
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3
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Jin T, Lin J, Gong Y, Bi X, Hu S, Lv Q, Chen J, Li X, Chen J, Zhang W, Wang M, Fu G. iPLA 2β Contributes to ER Stress-Induced Apoptosis during Myocardial Ischemia/Reperfusion Injury. Cells 2021; 10:1446. [PMID: 34207793 PMCID: PMC8227999 DOI: 10.3390/cells10061446] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 06/02/2021] [Accepted: 06/07/2021] [Indexed: 01/09/2023] Open
Abstract
Both calcium-independent phospholipase A2 beta (iPLA2β) and endoplasmic reticulum (ER) stress regulate important pathophysiological processes including inflammation, calcium homeostasis and apoptosis. However, their roles in ischemic heart disease are poorly understood. Here, we show that the expression of iPLA2β is increased during myocardial ischemia/reperfusion (I/R) injury, concomitant with the induction of ER stress and the upregulation of cell death. We further show that the levels of iPLA2β in serum collected from acute myocardial infarction (AMI) patients and in samples collected from both in vivo and in vitro I/R injury models are significantly elevated. Further, iPLA2β knockout mice and siRNA mediated iPLA2β knockdown are employed to evaluate the ER stress and cell apoptosis during I/R injury. Additionally, cell surface protein biotinylation and immunofluorescence assays are used to trace and locate iPLA2β. Our data demonstrate the increase of iPLA2β augments ER stress and enhances cardiomyocyte apoptosis during I/R injury in vitro and in vivo. Inhibition of iPLA2β ameliorates ER stress and decreases cell death. Mechanistically, iPLA2β promotes ER stress and apoptosis by translocating to ER upon myocardial I/R injury. Together, our study suggests iPLA2β contributes to ER stress-induced apoptosis during myocardial I/R injury, which may serve as a potential therapeutic target against ischemic heart disease.
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Affiliation(s)
- Tingting Jin
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310020, China; (T.J.); (J.L.); (Y.G.); (X.B.); (S.H.); (Q.L.); (X.L.)
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310027, China; (J.C.); (J.C.)
| | - Jun Lin
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310020, China; (T.J.); (J.L.); (Y.G.); (X.B.); (S.H.); (Q.L.); (X.L.)
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310027, China; (J.C.); (J.C.)
| | - Yingchao Gong
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310020, China; (T.J.); (J.L.); (Y.G.); (X.B.); (S.H.); (Q.L.); (X.L.)
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310027, China; (J.C.); (J.C.)
| | - Xukun Bi
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310020, China; (T.J.); (J.L.); (Y.G.); (X.B.); (S.H.); (Q.L.); (X.L.)
| | - Shasha Hu
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310020, China; (T.J.); (J.L.); (Y.G.); (X.B.); (S.H.); (Q.L.); (X.L.)
| | - Qingbo Lv
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310020, China; (T.J.); (J.L.); (Y.G.); (X.B.); (S.H.); (Q.L.); (X.L.)
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310027, China; (J.C.); (J.C.)
| | - Jiaweng Chen
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310027, China; (J.C.); (J.C.)
| | - Xiaoting Li
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310020, China; (T.J.); (J.L.); (Y.G.); (X.B.); (S.H.); (Q.L.); (X.L.)
| | - Jiaqi Chen
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310027, China; (J.C.); (J.C.)
| | - Wenbin Zhang
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310020, China; (T.J.); (J.L.); (Y.G.); (X.B.); (S.H.); (Q.L.); (X.L.)
| | - Meihui Wang
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310027, China; (J.C.); (J.C.)
| | - Guosheng Fu
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310020, China; (T.J.); (J.L.); (Y.G.); (X.B.); (S.H.); (Q.L.); (X.L.)
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310027, China; (J.C.); (J.C.)
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4
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Imai H, Saijo K, Chikamatsu S, Kawamura Y, Ishioka C. LPIN1 downregulation enhances anticancer activity of the novel HDAC/PI3K dual inhibitor FK-A11. Cancer Sci 2021; 112:792-802. [PMID: 33274548 PMCID: PMC7894020 DOI: 10.1111/cas.14759] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 11/24/2020] [Accepted: 11/25/2020] [Indexed: 12/14/2022] Open
Abstract
Phosphatidylinositol-3 kinase (PI3K) inhibitor and histone deacetylase (HDAC) inhibitor have been developed as potential anticancer drugs. However, the cytotoxicity of PI3K inhibitor or HDAC inhibitor alone is relatively weak. We recently developed a novel HDAC/PI3K dual inhibitor FK-A11 and confirmed its enhanced cytotoxicity when compared to that of PI3K inhibitor or HDAC inhibitor alone on several cancer cell lines. However, the in vivo antitumor activity of FK-A11 was insufficient. We conducted high-throughput RNA interfering screening and identified gene LPIN1 which enhances the cytotoxicity of FK-A11. Downregulation of LPIN1 enhanced simultaneous inhibition of HDAC and PI3K by FK-A11 and enhanced the cytotoxicity of FK-A11. Propranolol, a beta-adrenoreceptor which is also a LPIN1 inhibitor, enhanced the in vitro and in vivo cytotoxicity and antitumor effect of FK-A11. These findings should help in the development of FK-A11 as a novel HDAC/PI3K dual inhibitor.
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Affiliation(s)
- Hiroo Imai
- Department of Clinical OncologyInstitute for Development, Aging and CancerTohoku UniversitySendaiJapan
| | - Ken Saijo
- Department of Clinical OncologyInstitute for Development, Aging and CancerTohoku UniversitySendaiJapan
| | - Sonoko Chikamatsu
- Department of Clinical OncologyInstitute for Development, Aging and CancerTohoku UniversitySendaiJapan
| | - Yoshifumi Kawamura
- Department of Clinical OncologyInstitute for Development, Aging and CancerTohoku UniversitySendaiJapan
| | - Chikashi Ishioka
- Department of Clinical OncologyInstitute for Development, Aging and CancerTohoku UniversitySendaiJapan
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5
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Monge P, Garrido A, Rubio JM, Magrioti V, Kokotos G, Balboa MA, Balsinde J. The Contribution of Cytosolic Group IVA and Calcium-Independent Group VIA Phospholipase A 2s to Adrenic Acid Mobilization in Murine Macrophages. Biomolecules 2020; 10:biom10040542. [PMID: 32260121 PMCID: PMC7226511 DOI: 10.3390/biom10040542] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 12/11/2022] Open
Abstract
Adrenic acid (AA), the 2-carbon elongation product of arachidonic acid, is present at significant levels in membrane phospholipids of mouse peritoneal macrophages. Despite its abundance and structural similarity to arachidonic acid, very little is known about the molecular mechanisms governing adrenic acid mobilization in cells of the innate immune system. This contrasts with the wide availability of data on arachidonic acid mobilization. In this work, we used mass-spectrometry-based lipidomic procedures to define the profiles of macrophage phospholipids that contain adrenic acid and their behavior during receptor activation. We identified the phospholipid sources from which adrenic acid is mobilized, and compared the data with arachidonic acid mobilization. Taking advantage of the use of selective inhibitors, we also showed that cytosolic group IVA phospholipase A2 is involved in the release of both adrenic and arachidonic acids. Importantly, calcium independent group VIA phospholipase A2 spared arachidonate-containing phospholipids and hydrolyzed only those that contain adrenic acid. These results identify separate mechanisms for regulating the utilization of adrenic and arachidonic acids, and suggest that the two fatty acids may serve non-redundant functions in cells.
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Affiliation(s)
- Patricia Monge
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Valladolid, 47003 Valladolid, Spain; (P.M.); (A.G.); (J.M.R.); (M.A.B.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain
| | - Alvaro Garrido
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Valladolid, 47003 Valladolid, Spain; (P.M.); (A.G.); (J.M.R.); (M.A.B.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain
| | - Julio M. Rubio
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Valladolid, 47003 Valladolid, Spain; (P.M.); (A.G.); (J.M.R.); (M.A.B.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain
| | - Victoria Magrioti
- Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, 15771 Athens, Greece; (V.M.); (G.K.)
| | - George Kokotos
- Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, 15771 Athens, Greece; (V.M.); (G.K.)
| | - María A. Balboa
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Valladolid, 47003 Valladolid, Spain; (P.M.); (A.G.); (J.M.R.); (M.A.B.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain
| | - Jesús Balsinde
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Valladolid, 47003 Valladolid, Spain; (P.M.); (A.G.); (J.M.R.); (M.A.B.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain
- Correspondence: ; Tel.: +34-983-423-062
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6
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Fernandes ACS, Soares DC, Neves RFC, Koeller CM, Heise N, Adade CM, Frases S, Meyer-Fernandes JR, Saraiva EM, Souto-Padrón T. Endocytosis and Exocytosis in Leishmania amazonensis Are Modulated by Bromoenol Lactone. Front Cell Infect Microbiol 2020; 10:39. [PMID: 32117812 PMCID: PMC7020749 DOI: 10.3389/fcimb.2020.00039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 01/21/2020] [Indexed: 12/15/2022] Open
Abstract
In the protozoan pathogen Leishmania, endocytosis, and exocytosis occur mainly in the small area of the flagellar pocket membrane, which makes this parasite an interesting model of strikingly polarized internalization and secretion. Moreover, little is known about vesicle recognition and fusion mechanisms, which are essential for both endo/exocytosis in this parasite. In other cell types, vesicle fusion events require the activity of phospholipase A2 (PLA2), including Ca2+-independent iPLA2 and soluble, Ca2+-dependent sPLA2. Here, we studied the role of bromoenol lactone (BEL) inhibition of endo/exocytosis in promastigotes of Leishmania amazonensis. PLA2 activities were assayed in intact parasites, in whole conditioned media, and in soluble and extracellular vesicles (EVs) conditioned media fractions. BEL did not affect the viability of promastigotes, but reduced the differentiation into metacyclic forms. Intact parasites and EVs had BEL-sensitive iPLA2 activity. BEL treatment reduced total EVs secretion, as evidenced by reduced total protein concentration, as well as its size distribution and vesicles in the flagellar pocket of treated parasites as observed by TEM. Membrane proteins, such as acid phosphatases and GP63, became concentrated in the cytoplasm, mainly in multivesicular tubules of the endocytic pathway. BEL also prevented the endocytosis of BSA, transferrin and ConA, with the accumulation of these markers in the flagellar pocket. These results suggested that the activity inhibited by BEL, which is one of the irreversible inhibitors of iPLA2, is required for both endocytosis and exocytosis in promastigotes of L. amazonensis.
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Affiliation(s)
- Anne C S Fernandes
- Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Deivid C Soares
- Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Roberta F C Neves
- Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carolina M Koeller
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Norton Heise
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Camila M Adade
- Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Susana Frases
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - José R Meyer-Fernandes
- Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil.,Centro de Ciências da Saúde, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Elvira M Saraiva
- Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Thaïs Souto-Padrón
- Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
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7
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Amplification of the COX/TXS/TP receptor pathway enhances uridine diphosphate-induced contraction by advanced glycation end products in rat carotid arteries. Pflugers Arch 2019; 471:1505-1517. [PMID: 31736003 DOI: 10.1007/s00424-019-02330-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 11/07/2019] [Accepted: 11/08/2019] [Indexed: 12/18/2022]
Abstract
Advanced glycation end products (AGEs) play a pivotal role in vascular functions under various pathophysiological conditions. Although uridine diphosphate (UDP) is an important extracellular nucleotide, the relationship between AGEs and UDP regarding their effect on vascular functions remains unclear. Therefore, we investigated the effects of AGE-bovine serum albumin (AGE-BSA) on UDP-mediated responses in rat thoracic aorta and carotid arteries. In rat thoracic aorta, UDP-induced relaxation was observed and this relaxation was similar between control (1.0 v/v% PBS) and AGE-BSA-treated (0.1 mg/mL for 60 min) groups. In contrast, contraction but not relaxation was obtained following UDP application to carotid arteries with and without endothelia; contraction was greater in the AGE-BSA-treated group than in the control group. The difference in UDP-induced contraction between the two groups was not abolished by the use of a nitric oxide synthase (NOS) inhibitor, whereas it was abolished by the use of cyclooxygenase (COX), thromboxane synthase (TXS), and thromboxane-prostanoid (TP) receptor antagonist. Further, the difference in UDP-induced contraction was not abolished by the use of a cPLA2 inhibitor, whereas it was abolished by the use of an iPLA2 inhibitor. UDP increased TXA2 release in both groups, and its level was similar in both groups. Moreover, the release of PGE2, PGF2α, and PGI2 was similar among the groups. Under NOS inhibition, TP receptor agonist-induced contraction increased in the AGE-BSA-treated group (vs. control group). In conclusion, the increase in UDP-induced carotid arterial contraction by AGE-BSA can be attributed to an increase in the COX/TXS/TP receptor pathway, particularly, TP receptor signaling.
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8
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Cellular Plasmalogen Content Does Not Influence Arachidonic Acid Levels or Distribution in Macrophages: A Role for Cytosolic Phospholipase A 2γ in Phospholipid Remodeling. Cells 2019; 8:cells8080799. [PMID: 31370188 PMCID: PMC6721556 DOI: 10.3390/cells8080799] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 07/26/2019] [Accepted: 07/30/2019] [Indexed: 12/12/2022] Open
Abstract
Availability of free arachidonic acid (AA) constitutes a rate limiting factor for cellular eicosanoid synthesis. AA distributes differentially across membrane phospholipids, which is largely due to the action of coenzyme A-independent transacylase (CoA-IT), an enzyme that moves the fatty acid primarily from diacyl phospholipid species to ether-containing species, particularly the ethanolamine plasmalogens. In this work, we examined the dependence of AA remodeling on plasmalogen content using the murine macrophage cell line RAW264.7 and its plasmalogen-deficient variants RAW.12 and RAW.108. All three strains remodeled AA between phospholipids with similar magnitude and kinetics, thus demonstrating that cellular plasmalogen content does not influence the process. Cell stimulation with yeast-derived zymosan also had no effect on AA remodeling, but incubating the cells in AA-rich media markedly slowed down the process. Further, knockdown of cytosolic-group IVC phospholipase A2γ (cPLA2γ) by RNA silencing significantly reduced AA remodeling, while inhibition of other major phospholipase A2 forms such as cytosolic phospholipase A2α, calcium-independent phospholipase A2β, or secreted phospholipase A2 had no effect. These results uncover new regulatory features of CoA-IT-mediated transacylation reactions in cellular AA homeostasis and suggest a hitherto unrecognized role for cPLA2γ in maintaining membrane phospholipid composition via regulation of AA remodeling.
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9
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Christerson U, Keita ÅV, Winberg ME, Söderholm JD, Gustafson-Svärd C. Possible Involvement of Intracellular Calcium-Independent Phospholipase A 2 in the Release of Secretory Phospholipases from Mast Cells-Increased Expression in Ileal Mast Cells of Crohn's Disease. Cells 2019; 8:cells8070672. [PMID: 31277247 PMCID: PMC6678282 DOI: 10.3390/cells8070672] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 06/27/2019] [Accepted: 07/01/2019] [Indexed: 12/24/2022] Open
Abstract
Increased activity of secretory phospholipases A2 (sPLA2) type-II was previously observed in ileum of Crohn’s disease (CD). Our aims were to explore the involvement of calcium-independent (i)PLA2β in the release of sPLA2s from the human mast cell (MC) line (HMC-1) and investigate expressions of cytosolic (c)PLA2α, iPLA2β, sPLA2-IIA and sPLA2-V in MCs of CD ileum. The release of sPLA2 was investigated in HMC-1 by immunocytochemistry and ELISA. The expression intensities of PLA2s in mucosal MCs, and the proportion of PLA2-positive MCs, were investigated in normal ileum and in ileum from patients with CD by immunohistochemistry. The calcium ionophore-stimulated release of sPLA2-IIA and sPLA2-V from HMC-1 was reduced by the iPLA2-inhibitor bromoenol lactone. All four PLA2s were detectable in mucosal MCs, both in normal ileum and in CD, but the proportion of iPLA2β-containing mucosal MCs and the expression intensity of sPLA2-IIA was increased in CD. Results indicate that iPLA2β is involved in the secretion of sPLA2s from HMC-1, and suggest that iPLA2β-mediated release of sPLA2 from intestinal MCs may contribute to CD pathophysiology. Ex vivo studies on isolated mucosal mast cells are however needed to clarify the precise role of MC PLA2s in the inflammatory processes of CD.
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Affiliation(s)
- Ulrika Christerson
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Sciences, Linnaeus University, 391 82 Kalmar, Sweden
| | - Åsa V Keita
- Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics & Oncology, Linköping University, 581 85 Linköping, Sweden
| | - Martin E Winberg
- Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics & Oncology, Linköping University, 581 85 Linköping, Sweden
| | - Johan D Söderholm
- Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics & Oncology, Linköping University, 581 85 Linköping, Sweden
- Department of Surgery, County Council of Östergötland, 581 85 Linköping, Sweden
| | - Christina Gustafson-Svärd
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Sciences, Linnaeus University, 391 82 Kalmar, Sweden
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10
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Zoeller RA, Geoghegan-Barek K. A cell-based high-throughput screen identifies tyrphostin AG 879 as an inhibitor of animal cell phospholipid and fatty acid biosynthesis. Biochem Biophys Rep 2019; 18:100621. [PMID: 30899803 PMCID: PMC6406593 DOI: 10.1016/j.bbrep.2019.100621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 02/18/2019] [Indexed: 01/02/2023] Open
Abstract
Inhibition of animal cell phospholipid biosynthesis has been proposed for anticancer and antiviral therapies. Using CHO—K1 derived cell lines, we have developed and used a cell-based high-throughput procedure to screen a 1280 compound, small molecule library for inhibitors of phospholipid biosynthesis. We identified tyrphostin AG 879 (AG879), which inhibited phospholipid biosynthesis by 85–90% at a concentration of 10 μM, displaying an IC50 of 1–3 μM. The synthesis of all phospholipid head group classes was heavily affected. Fatty acid biosynthesis was also dramatically inhibited (90%). AG879 inhibited phospholipid biosynthesis in all additional cell lines tested, including MDCK, HUH7, Vero, and HeLa cell lines. In CHO cells, AG879 was cytostatic; cells survived for at least four days during exposure and were able to divide following its removal. AG879 is an inhibitor of receptor tyrosine kinases (RTK) and inhibitors of signaling pathways known to be activated by RTK's also inhibited phospholipid biosynthesis. We speculate that inhibition of RTK by AG879 results in an inhibition of fatty acid biosynthesis with a resulting decrease in phospholipid biosynthesis and that AG879's effect on fatty acid synthesis and/or phospholipid biosynthesis may contribute to its known capacity as an effective antiviral/anticancer agent.
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Key Words
- 32Pi, [32P]orthophosphate
- AFU, Arbitrary fluorescence units
- AG879, Tyrphostin AG 879
- Anticancer
- Antiviral
- CE, Cholesterol ester
- CL, Cardiolipin
- Drug screening
- EGFR, Epidermal growth factor receptor
- Fatty acid biosynthesis
- HER2, Human epidermal growth factor receptor 2
- HTS, High-throughput screen
- P12, 12-(1′-pyrene) dodecanoic acid
- PA, Phosphatidic acid
- PC, Phosphatidylcholine
- PE, Phosphatidylethanolamine
- PI, Phosphatidylinositol
- PL, Phospholipid
- Phospholipid biosynthesis
- RTK, Receptor tyrosine kinase
- TG, Triacylglycerol
- Tyrphostin AG 879
- trkA, Tropomyosin analogue receptor kinase
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Affiliation(s)
- Raphael A Zoeller
- Department of Physiology & Biophysics, Boston University School of Medicine, 700 Albany Street, Room W302, Boston, MA, 02118, USA
| | - Kathleen Geoghegan-Barek
- Department of Physiology & Biophysics, Boston University School of Medicine, 700 Albany Street, Room W302, Boston, MA, 02118, USA
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11
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Guo YP, Tang BS, Liu HL, Huang JJ, Xu Q, Sun QY, Yan XX, Guo JF. Impaired iPLA 2β activity affects iron uptake and storage without iron accumulation: An in vitro study excluding decreased iPLA 2β activity as the cause of iron deposition in PLAN. Brain Res 2019; 1712:25-33. [PMID: 30707893 DOI: 10.1016/j.brainres.2019.01.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/13/2019] [Accepted: 01/27/2019] [Indexed: 01/12/2023]
Abstract
PLA2G6-associated neurodegeneration (PLAN, NBIA2) is the second most common type of neurodegeneration with brain iron accumulation (NBIA), caused by recessive mutations of PLA2G6 gene, which encodes Ca2+-independent phospholipase A2β (iPLA2β). In most PLAN cases, decreased iPLA2β activity and iron deposition was observed meanwhile, and researchers also identified a PLA2G6 mutation family without iron deposition shown by MRI images. This brought us the question of whether decreased iPLA2β activity was the cause of iron deposition in PLAN. In this study, we used S-BEL as the antagonist of iPLA2β to block its activity and used SH-SY5Y cells as the expression system. We incubated SH-SY5Y cells with different concentrations of S-BEL. The results showed that decreased iPLA2β activity led no obvious iron accumulation, while changes of cells state and activation of apoptosis were observed. To further investigate the cause of unchanged iron level, we examined the cellular iron regulatory proteins involved in iron uptake, storage and export. The results were as follows: TfR1 (iron uptake protein) expression was decreased, the expression of ferritin heavy chain and light chain (iron storage protein) was increased. There was no alteration of the expression of DMT1 (iron uptake protein) and FPN1 (iron export protein). Under the condition of decreased iPLA2β activity, there was no obvious iron accumulation but iron uptake activity decreased and iron storage activity increased. Therefore, we speculate that the decreased iPLA2β activity may not be the main reason for iron deposition in PLAN.
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Affiliation(s)
- Yu-Pei Guo
- Center for Brain Disorders Research, Capital Medical University and Beijing Institute of Brain Disorders, Beijing 100069, People's Republic of China; Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China
| | - Bei-Sha Tang
- Center for Brain Disorders Research, Capital Medical University and Beijing Institute of Brain Disorders, Beijing 100069, People's Republic of China; Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China; National Clinical Research Center for Geriatric Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China; Center for Medical Genetics, Central South University, Changsha 410008, Hunan, People's Republic of China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China
| | - Hong-Li Liu
- Center for Brain Disorders Research, Capital Medical University and Beijing Institute of Brain Disorders, Beijing 100069, People's Republic of China; Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China
| | - Juan-Juan Huang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China
| | - Qian Xu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China; National Clinical Research Center for Geriatric Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China
| | - Qi-Ying Sun
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China; National Clinical Research Center for Geriatric Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China
| | - Xin-Xiang Yan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China
| | - Ji-Feng Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China; National Clinical Research Center for Geriatric Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China; Center for Medical Genetics, Central South University, Changsha 410008, Hunan, People's Republic of China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China.
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12
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Lowered iPLA2γ activity causes increased mitochondrial lipid peroxidation and mitochondrial dysfunction in a rotenone-induced model of Parkinson's disease. Exp Neurol 2018; 300:74-86. [DOI: 10.1016/j.expneurol.2017.10.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/26/2017] [Accepted: 10/30/2017] [Indexed: 12/25/2022]
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13
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PEDF Inhibits the Activation of NLRP3 Inflammasome in Hypoxia Cardiomyocytes through PEDF Receptor/Phospholipase A2. Int J Mol Sci 2016; 17:ijms17122064. [PMID: 27973457 PMCID: PMC5187864 DOI: 10.3390/ijms17122064] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/26/2016] [Accepted: 12/02/2016] [Indexed: 12/23/2022] Open
Abstract
The nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome has been linked to sterile inflammation, which is involved in ischemic injury in myocardial cells. Pigment epithelium-derived factor (PEDF) is a multifunctional secreted glycoprotein with many biological activities, such as anti-inflammatory, antioxidant and anti-angiogenic properties. However, it is not known whether and how PEDF acts to regulate the activation of the NLRP3 inflammasome in cardiomyocytes. In the present study, we used the neonatal cardiomyocytes models of ischemia-like conditions to evaluate the mitochondrial fission and the activation of the NLRP3 inflammasome. We also determined the mechanism by which PEDF inhibits hypoxia-induced activation of the NLRP3 inflammasome. We found that PEDF decreased the activation of the NLRP3 inflammasome in neonatal cardiomyocytes through pigment epithelial-derived factor receptor/calcium-independent phospholipase A2 (PEDFR/iPLA2). Meanwhile, PEDF reduced Drp1-induced mitochondrial fission and mitochondrial fission-induced mitochondrial DNA (mtDNA), as well as mitochondrial reactive oxygen species (mtROS) release into cytosol through PEDFR/iPLA2. We also found that PEDF inhibited mitochondrial fission-induced NLRP3 inflammasome activation. Furthermore, previous research has found that endogenous cytosolic mtDNA and mtROS can serve as activators of NLRP3 inflammasome activity. Therefore, we hypothesized that PEDF can protect against hypoxia-induced activation of the NLRP3 inflammasome by inhibiting mitochondrial fission though PEDFR/iPLA2.
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14
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Brohée L, Demine S, Willems J, Arnould T, Colige AC, Deroanne CF. Lipin-1 regulates cancer cell phenotype and is a potential target to potentiate rapamycin treatment. Oncotarget 2016; 6:11264-80. [PMID: 25834103 PMCID: PMC4484455 DOI: 10.18632/oncotarget.3595] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 02/20/2015] [Indexed: 01/30/2023] Open
Abstract
Lipogenesis inhibition was reported to induce apoptosis and repress proliferation of cancer cells while barely affecting normal cells. Lipins exhibit dual function as enzymes catalyzing the dephosphorylation of phosphatidic acid to diacylglycerol and as co-transcriptional regulators. Thus, they are able to regulate lipid homeostasis at several nodal points. Here, we show that lipin-1 is up-regulated in several cancer cell lines and overexpressed in 50 % of high grade prostate cancers. The proliferation of prostate and breast cancer cells, but not of non-tumorigenic cells, was repressed upon lipin-1 knock-down. Lipin-1 depletion also decreased cancer cell migration through RhoA activation. Lipin-1 silencing did not significantly affect global lipid synthesis but enhanced the cellular concentration of phosphatidic acid. In parallel, autophagy was induced while AKT and ribosomal protein S6 phosphorylation were repressed. We also observed a compensatory regulation between lipin-1 and lipin-2 and demonstrated that their co-silencing aggravates the phenotype induced by lipin-1 silencing alone. Most interestingly, lipin-1 depletion or lipins inhibition with propranolol sensitized cancer cells to rapamycin. These data indicate that lipin-1 controls main cellular processes involved in cancer progression and that its targeting, alone or in combination with other treatments, could open new avenues in anticancer therapy.
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Affiliation(s)
- Laura Brohée
- Laboratory of Connective Tissues Biology, GIGA-Cancer, University of Liège, Tour de Pathologie, Sart-Tilman, Belgium
| | - Stéphane Demine
- Laboratory of Biochemistry and Cell Biology (URBC), NARILIS (Namur Research Institute for Life Sciences), University of Namur (UNamur), Namur, Belgium
| | - Jérome Willems
- Laboratory of Connective Tissues Biology, GIGA-Cancer, University of Liège, Tour de Pathologie, Sart-Tilman, Belgium
| | - Thierry Arnould
- Laboratory of Biochemistry and Cell Biology (URBC), NARILIS (Namur Research Institute for Life Sciences), University of Namur (UNamur), Namur, Belgium
| | - Alain C Colige
- Laboratory of Connective Tissues Biology, GIGA-Cancer, University of Liège, Tour de Pathologie, Sart-Tilman, Belgium
| | - Christophe F Deroanne
- Laboratory of Connective Tissues Biology, GIGA-Cancer, University of Liège, Tour de Pathologie, Sart-Tilman, Belgium
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15
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Ramanadham S, Ali T, Ashley JW, Bone RN, Hancock WD, Lei X. Calcium-independent phospholipases A2 and their roles in biological processes and diseases. J Lipid Res 2015; 56:1643-68. [PMID: 26023050 DOI: 10.1194/jlr.r058701] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Indexed: 12/24/2022] Open
Abstract
Among the family of phospholipases A2 (PLA2s) are the Ca(2+)-independent PLA2s (iPLA2s) and they are designated group VI iPLA2s. In relation to secretory and cytosolic PLA2s, the iPLA2s are more recently described and details of their expression and roles in biological functions are rapidly emerging. The iPLA2s or patatin-like phospholipases (PNPLAs) are intracellular enzymes that do not require Ca(2+) for activity, and contain lipase (GXSXG) and nucleotide-binding (GXGXXG) consensus sequences. Though nine PNPLAs have been recognized, PNPLA8 (membrane-associated iPLA2γ) and PNPLA9 (cytosol-associated iPLA2β) are the most widely studied and understood. The iPLA2s manifest a variety of activities in addition to phospholipase, are ubiquitously expressed, and participate in a multitude of biological processes, including fat catabolism, cell differentiation, maintenance of mitochondrial integrity, phospholipid remodeling, cell proliferation, signal transduction, and cell death. As might be expected, increased or decreased expression of iPLA2s can have profound effects on the metabolic state, CNS function, cardiovascular performance, and cell survival; therefore, dysregulation of iPLA2s can be a critical factor in the development of many diseases. This review is aimed at providing a general framework of the current understanding of the iPLA2s and discussion of the potential mechanisms of action of the iPLA2s and related involved lipid mediators.
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Affiliation(s)
- Sasanka Ramanadham
- Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294 Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Tomader Ali
- Undergraduate Research Office, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Jason W Ashley
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA 19104
| | - Robert N Bone
- Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294 Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - William D Hancock
- Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294 Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Xiaoyong Lei
- Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294 Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
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16
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Bone RN, Gai Y, Magrioti V, Kokotou MG, Ali T, Lei X, Tse HM, Kokotos G, Ramanadham S. Inhibition of Ca2+-independent phospholipase A2β (iPLA2β) ameliorates islet infiltration and incidence of diabetes in NOD mice. Diabetes 2015; 64:541-54. [PMID: 25213337 PMCID: PMC4303959 DOI: 10.2337/db14-0097] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 09/02/2014] [Indexed: 12/14/2022]
Abstract
Autoimmune β-cell death leads to type 1 diabetes, and with findings that Ca(2+)-independent phospholipase A2β (iPLA2β) activation contributes to β-cell death, we assessed the effects of iPLA2β inhibition on diabetes development. Administration of FKGK18, a reversible iPLA2β inhibitor, to NOD female mice significantly reduced diabetes incidence in association with 1) reduced insulitis, reflected by reductions in CD4(+) T cells and B cells; 2) improved glucose homeostasis; 3) higher circulating insulin; and 4) β-cell preservation. Furthermore, FKGK18 inhibited production of tumor necrosis factor-α (TNF-α) from CD4(+) T cells and antibodies from B cells, suggesting modulation of immune cell responses by iPLA2β-derived products. Consistent with this, 1) adoptive transfer of diabetes by CD4(+) T cells to immunodeficient and diabetes-resistant NOD.scid mice was mitigated by FKGK18 pretreatment and 2) TNF-α production from CD4(+) T cells was reduced by inhibitors of cyclooxygenase and 12-lipoxygenase, which metabolize arachidonic acid to generate bioactive inflammatory eicosanoids. However, adoptive transfer of diabetes was not prevented when mice were administered FKGK18-pretreated T cells or when FKGK18 administration was initiated with T-cell transfer. The present observations suggest that iPLA2β-derived lipid signals modulate immune cell responses, raising the possibility that early inhibition of iPLA2β may be beneficial in ameliorating autoimmune destruction of β-cells and mitigating type 1 diabetes development.
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Affiliation(s)
- Robert N Bone
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL
| | - Ying Gai
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL
| | - Victoria Magrioti
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Athens, Greece
| | - Maroula G Kokotou
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Athens, Greece
| | - Tomader Ali
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL
| | - Xiaoyong Lei
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL
| | - Hubert M Tse
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL
| | - George Kokotos
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Athens, Greece
| | - Sasanka Ramanadham
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL
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17
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Shalini SM, Chew WS, Rajkumar R, Dawe GS, Ong WY. Role of constitutive calcium-independent phospholipase A2 beta in hippocampo-prefrontal cortical long term potentiation and spatial working memory. Neurochem Int 2014; 78:96-104. [PMID: 25180675 DOI: 10.1016/j.neuint.2014.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Revised: 08/04/2014] [Accepted: 08/22/2014] [Indexed: 01/29/2023]
Abstract
Calcium independent phospholipase A2 (iPLA2) is an 85 kDa protein that catalyzes the hydrolysis of the sn-2 acyl ester bond of glycerophospholipids to liberate free fatty acids and lysophospholipids. In this study, we determined the role of constitutive iPLA2β in long term potentiation (LTP) of the hippocampo-prefrontal cortical pathway in vivo. We also examined the effect of iPLA2β knockdown using the rewarded alternation in T-maze task, a test of spatial working memory which is dependent on this pathway. Intracortical injection of an inhibitor to iPLA2, bromoenol lactone (BEL) or antisense oligonucleotide to iPLA2β in the prefrontal cortex abolished induction of hippocampo-prefrontal cortical LTP. Moreover, iPLA2 inhibition and antisense knockdown resulted in increased errors in the rewarded alternation in T-maze task, indicating negative effects on spatial working memory. BEL or antisense injection did not produce DNA fragmentation in the cortex as demonstrated by TUNEL assay. Results confirm a role of constitutive iPLA2β in hippocampo-prefrontal cortical synaptic plasticity in vivo, and add to previous observations of a role of iPLA2 in hippocampal LTP in vitro, and long-term memory retrieval. They may be relevant in Alzheimer's disease, and other neurodegenerative conditions that are associated with changes in iPLA2.
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Affiliation(s)
- Suku-Maran Shalini
- Department of Anatomy, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore
| | - Wee-Siong Chew
- Department of Anatomy, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore
| | - Ramamoorthy Rajkumar
- Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore; Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
| | - Gavin S Dawe
- Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore; Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
| | - Wei-Yi Ong
- Department of Anatomy, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore.
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18
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Shaughnessy R, Retamal C, Oyanadel C, Norambuena A, López A, Bravo-Zehnder M, Montecino FJ, Metz C, Soza A, González A. Epidermal growth factor receptor endocytic traffic perturbation by phosphatidate phosphohydrolase inhibition: new strategy against cancer. FEBS J 2014; 281:2172-89. [PMID: 24597955 DOI: 10.1111/febs.12770] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 02/02/2014] [Accepted: 02/26/2014] [Indexed: 01/11/2023]
Abstract
Epidermal growth factor receptor (EGFR) exaggerated (oncogenic) function is currently targeted in cancer treatment with drugs that block receptor ligand binding or tyrosine kinase activity. Because endocytic trafficking is a crucial regulator of EGFR function, its pharmacological perturbation might provide a new anti-tumoral strategy. Inhibition of phosphatidic acid (PA) phosphohydrolase (PAP) activity has been shown to trigger PA signaling towards type 4 phosphodiesterase (PDE4) activation and protein kinase A inhibition, leading to internalization of empty/inactive EGFR. Here, we used propranolol, its l- and d- isomers and desipramine as PAP inhibitors to further explore the effects of PAP inhibition on EGFR endocytic trafficking and its consequences on EGFR-dependent cancer cell line models. PAP inhibition not only made EGFR inaccessible to stimuli but also prolonged the signaling lifetime of ligand-activated EGFR in recycling endosomes. Strikingly, such endocytic perturbations applied in acute/intermittent PAP inhibitor treatments selectively impaired cell proliferation/viability sustained by an exaggerated EGFR function. Phospholipase D inhibition with FIPI (5-fluoro-2-indolyl des-chlorohalopemide) and PDE4 inhibition with rolipram abrogated both the anti-tumoral and endocytic effects of PAP inhibition. Prolonged treatments with a low concentration of PAP inhibitors, although without detectable endocytic effects, still counteracted cell proliferation, induced apoptosis and decreased anchorage-independent growth of cells bearing EGFR oncogenic influences. Overall, our results show that PAP inhibitors can counteract EGFR oncogenic traits, including receptor overexpression or activating mutations resistant to current tyrosine kinase inhibitors, perturbing EGFR endocytic trafficking and perhaps other as yet unknown processes, depending on treatment conditions. This puts PAP activity forward as a new suitable target against EGFR-driven malignancy.
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Affiliation(s)
- Ronan Shaughnessy
- Departamento de Inmunología Clínica y Reumatología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile; Centro de Envejecimiento y Regeneración, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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19
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Ali T, Kokotos G, Magrioti V, Bone RN, Mobley JA, Hancock W, Ramanadham S. Characterization of FKGK18 as inhibitor of group VIA Ca2+-independent phospholipase A2 (iPLA2β): candidate drug for preventing beta-cell apoptosis and diabetes. PLoS One 2013; 8:e71748. [PMID: 23977134 PMCID: PMC3748103 DOI: 10.1371/journal.pone.0071748] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 06/30/2013] [Indexed: 01/27/2023] Open
Abstract
Ongoing studies suggest an important role for iPLA2β in a multitude of biological processes and it has been implicated in neurodegenerative, skeletal and vascular smooth muscle disorders, bone formation, and cardiac arrhythmias. Thus, identifying an iPLA2βinhibitor that can be reliably and safely used in vivo is warranted. Currently, the mechanism-based inhibitor bromoenol lactone (BEL) is the most widely used to discern the role of iPLA2β in biological processes. While BEL is recognized as a more potent inhibitor of iPLA2 than of cPLA2 or sPLA2, leading to its designation as a "specific" inhibitor of iPLA2, it has been shown to also inhibit non-PLA2 enzymes. A potential complication of its use is that while the S and R enantiomers of BEL exhibit preference for cytosol-associated iPLA2β and membrane-associated iPLA2γ, respectively, the selectivity is only 10-fold for both. In addition, BEL is unstable in solution, promotes irreversible inhibition, and may be cytotoxic, making BEL not amenable for in vivo use. Recently, a fluoroketone (FK)-based compound (FKGK18) was described as a potent inhibitor of iPLA2β. Here we characterized its inhibitory profile in beta-cells and find that FKGK18: (a) inhibits iPLA2β with a greater potency (100-fold) than iPLA2γ, (b) inhibition of iPLA2β is reversible, (c) is an ineffective inhibitor of α-chymotrypsin, and (d) inhibits previously described outcomes of iPLA2β activation including (i) glucose-stimulated insulin secretion, (ii) arachidonic acid hydrolysis; as reflected by PGE2 release from human islets, (iii) ER stress-induced neutral sphingomyelinase 2 expression, and (iv) ER stress-induced beta-cell apoptosis. These findings suggest that FKGK18 is similar to BEL in its ability to inhibit iPLA2β. Because, in contrast to BEL, it is reversible and not a non-specific inhibitor of proteases, it is suggested that FKGK18 is more ideal for ex vivo and in vivo assessments of iPLA2β role in biological functions.
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Affiliation(s)
- Tomader Ali
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
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20
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Moon SH, Jenkins CM, Kiebish MA, Sims HF, Mancuso DJ, Gross RW. Genetic ablation of calcium-independent phospholipase A(2)γ (iPLA(2)γ) attenuates calcium-induced opening of the mitochondrial permeability transition pore and resultant cytochrome c release. J Biol Chem 2012; 287:29837-50. [PMID: 22778252 DOI: 10.1074/jbc.m112.373654] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Herein, we demonstrate that calcium-independent phospholipase A(2)γ (iPLA(2)γ) is a critical mechanistic participant in the calcium-induced opening of the mitochondrial permeability transition pore (mPTP). Liver mitochondria from iPLA(2)γ(-/-) mice were markedly resistant to calcium-induced swelling in the presence or absence of phosphate in comparison with wild-type littermates. Furthermore, the iPLA(2)γ enantioselective inhibitor (R)-(E)-6-(bromomethylene)-3-(1-naphthalenyl)-2H-tetrahydropyran-2-one ((R)-BEL) was markedly more potent than (S)-BEL in inhibiting mPTP opening in mitochondria from wild-type liver in comparison with hepatic mitochondria from iPLA(2)γ(-/-) mice. Intriguingly, low micromolar concentrations of long chain fatty acyl-CoAs and the non-hydrolyzable thioether analog of palmitoyl-CoA markedly accelerated Ca(2+)-induced mPTP opening in liver mitochondria from wild-type mice. The addition of l-carnitine enabled the metabolic channeling of acyl-CoA through carnitine palmitoyltransferases (CPT-1/2) and attenuated the palmitoyl-CoA-mediated amplification of calcium-induced mPTP opening. In contrast, mitochondria from iPLA(2)γ(-/-) mice were insensitive to fatty acyl-CoA-mediated augmentation of calcium-induced mPTP opening. Moreover, mitochondria from iPLA(2)γ(-/-) mouse liver were resistant to Ca(2+)/t-butyl hydroperoxide-induced mPTP opening in comparison with wild-type littermates. In support of these findings, cytochrome c release from iPLA(2)γ(-/-) mitochondria was dramatically decreased in response to calcium in the presence or absence of either t-butyl hydroperoxide or phenylarsine oxide in comparison with wild-type littermates. Collectively, these results identify iPLA(2)γ as an important mechanistic component of the mPTP, define its downstream products as potent regulators of mPTP opening, and demonstrate the integrated roles of mitochondrial bioenergetics and lipidomic flux in modulating mPTP opening promoting the activation of necrotic and necroapoptotic pathways of cell death.
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Affiliation(s)
- Sung Ho Moon
- Department of Medicine, Division of Bioorganic Chemistry and Molecular Pharmacology, Washington University School of Medicine, St. Louis, MO 63110, USA
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21
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Paliege A, Roeschel T, Neymeyer H, Seidel S, Kahl T, Daigeler AL, Mutig K, Mrowka R, Ferreri NR, Wilson BS, Himmerkus N, Bleich M, Bachmann S. Group VIA phospholipase A2 is a target for vasopressin signaling in the thick ascending limb. Am J Physiol Renal Physiol 2012; 302:F865-74. [DOI: 10.1152/ajprenal.00222.2011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Na+-K+-2Cl− cotransporter (NKCC2)-mediated NaCl reabsorption in the thick ascending limb (TAL) is stimulated by AVP via V2 receptor/PKA/cAMP signaling. This process is antagonized by locally produced eicosanoids such as 20-HETE or prostaglandin E2, which are synthesized in a phospholipase A2-dependent reaction cascade. Using microarray-based gene expression analysis, we found evidence for an AVP-dependent downregulation of the calcium-independent isoform of PLA2, iPLA2β, in the outer medulla of rats. In the present study, we therefore examined the contribution of iPLA2β to NKCC2 regulation. Immunoreactive iPLA2β protein was detected in cultured mTAL cells as well as in the entire TAL of rodents and humans with the exception of the macula densa. Administration of the V2 receptor-selective agonist desmopressin (5 ng/h; 3 days) to AVP-deficient diabetes insipidus rats increased outer medullary phosphorylated NKCC2 (pNKCC2) levels more than twofold in association with a marked reduction in iPLA2β abundance (−65%; P < 0.05), thus confirming microarray results. Inhibition of iPLA2β in Sprague-Dawley rats with FKGK 11 (0.5 μM) or in mTAL cells with FKGK 11 (10 μM) or ( S)-bromoenol lactone (5 μM) for 1 h markedly increased pNKCC2 levels without affecting total NKCC2 expression. Collectively, these data indicate that iPLA2β acts as an inhibitory modulator of NKCC2 activity and suggest that downregulation of iPLA2β may be a relevant step in AVP-mediated urine concentration.
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Affiliation(s)
- A. Paliege
- Department of Anatomy, Charité Universitätsmedizin-Berlin, Berlin
| | - T. Roeschel
- Department of Anatomy, Charité Universitätsmedizin-Berlin, Berlin
| | - H. Neymeyer
- Department of Anatomy, Charité Universitätsmedizin-Berlin, Berlin
| | - S. Seidel
- Department of Anatomy, Charité Universitätsmedizin-Berlin, Berlin
| | - T. Kahl
- Department of Anatomy, Charité Universitätsmedizin-Berlin, Berlin
| | - A. L. Daigeler
- Department of Anatomy, Charité Universitätsmedizin-Berlin, Berlin
| | - K. Mutig
- Department of Anatomy, Charité Universitätsmedizin-Berlin, Berlin
| | - R. Mrowka
- KIM3-Experimentelle Nephrologie, Universitätsklinikum Jena, Jena
| | - N. R. Ferreri
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - B. S. Wilson
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico; and
| | - N. Himmerkus
- Department of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - M. Bleich
- Department of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - S. Bachmann
- Department of Anatomy, Charité Universitätsmedizin-Berlin, Berlin
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22
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Moon SH, Jenkins CM, Liu X, Guan S, Mancuso DJ, Gross RW. Activation of mitochondrial calcium-independent phospholipase A2γ (iPLA2γ) by divalent cations mediating arachidonate release and production of downstream eicosanoids. J Biol Chem 2012; 287:14880-95. [PMID: 22389508 DOI: 10.1074/jbc.m111.336776] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Calcium-independent phospholipase A(2)γ (iPLA(2)γ) (PNPLA8) is the predominant phospholipase activity in mammalian mitochondria. However, the chemical mechanisms that regulate its activity are unknown. Here, we utilize iPLA(2)γ gain of function and loss of function genetic models to demonstrate the robust activation of iPLA(2)γ in murine myocardial mitochondria by Ca(2+) or Mg(2+) ions. Calcium ion stimulated the production of 2-arachidonoyl-lysophosphatidylcholine (2-AA-LPC) from 1-palmitoyl-2-[(14)C]arachidonoyl-sn-glycero-3-phosphocholine during incubations with wild-type heart mitochondrial homogenates. Furthermore, incubation of mitochondrial homogenates from transgenic myocardium expressing iPLA(2)γ resulted in 13- and 25-fold increases in the initial rate of radiolabeled 2-AA-LPC and arachidonic acid (AA) production, respectively, in the presence of calcium ion. Mass spectrometric analysis of the products of calcium-activated hydrolysis of endogenous mitochondrial phospholipids in transgenic iPLA(2)γ mitochondria revealed the robust production of AA, 2-AA-LPC, and 2-docosahexaenoyl-LPC that was over 10-fold greater than wild-type mitochondria. The mechanism-based inhibitor (R)-(E)-6-(bromomethylene)-3-(1-naphthalenyl)-2H-tetrahydropyran-2-one (BEL) (iPLA(2)γ selective), but not its enantiomer, (S)-BEL (iPLA(2)β selective) or pyrrolidine (cytosolic PLA(2)α selective), markedly attenuated Ca(2+)-dependent fatty acid release and polyunsaturated LPC production. Moreover, Ca(2+)-induced iPLA(2)γ activation was accompanied by the production of downstream eicosanoid metabolites that were nearly completely ablated by (R)-BEL or by genetic ablation of iPLA(2)γ. Intriguingly, Ca(2+)-induced iPLA(2)γ activation was completely inhibited by long-chain acyl-CoA (IC(50) ∼20 μm) as well as by a nonhydrolyzable acyl-CoA thioether analog. Collectively, these results demonstrate that mitochondrial iPLA(2)γ is activated by divalent cations and inhibited by acyl-CoA modulating the generation of biologically active metabolites that regulate mitochondrial bioenergetic and signaling functions.
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Affiliation(s)
- Sung Ho Moon
- Department of Medicine, Division of Bioorganic Chemistry and Molecular Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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23
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Ueno N, Taketomi Y, Yamamoto K, Hirabayashi T, Kamei D, Kita Y, Shimizu T, Shinzawa K, Tsujimoto Y, Ikeda K, Taguchi R, Murakami M. Analysis of two major intracellular phospholipases A(2) (PLA(2)) in mast cells reveals crucial contribution of cytosolic PLA(2)α, not Ca(2+)-independent PLA(2)β, to lipid mobilization in proximal mast cells and distal fibroblasts. J Biol Chem 2011; 286:37249-63. [PMID: 21880721 DOI: 10.1074/jbc.m111.290312] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mast cells release a variety of mediators, including arachidonic acid (AA) metabolites, to regulate allergy, inflammation, and host defense, and their differentiation and maturation within extravascular microenvironments depend on the stromal cytokine stem cell factor. Mouse mast cells express two major intracellular phospholipases A(2) (PLA(2)s), namely group IVA cytosolic PLA(2) (cPLA(2)α) and group VIA Ca(2+)-independent PLA(2) (iPLA(2)β), and the role of cPLA(2)α in eicosanoid synthesis by mast cells has been well documented. Lipidomic analyses of mouse bone marrow-derived mast cells (BMMCs) lacking cPLA(2)α (Pla2g4a(-/-)) or iPLA(2)β (Pla2g6(-/-)) revealed that phospholipids with AA were selectively hydrolyzed by cPLA(2)α, not by iPLA(2)β, during FcεRI-mediated activation and even during fibroblast-dependent maturation. Neither FcεRI-dependent effector functions nor maturation-driven phospholipid remodeling was impaired in Pla2g6(-/-) BMMCs. Although BMMCs did not produce prostaglandin E(2) (PGE(2)), the AA released by cPLA(2)α from BMMCs during maturation was converted to PGE(2) by microsomal PGE synthase-1 (mPGES-1) in cocultured fibroblasts, and accordingly, Pla2g4a(-/-) BMMCs promoted microenvironmental PGE(2) synthesis less efficiently than wild-type BMMCs both in vitro and in vivo. Mice deficient in mPGES-1 (Ptges(-/-)) had an augmented local anaphylactic response. These results suggest that cPLA(2)α in mast cells is functionally coupled, through the AA transfer mechanism, with stromal mPGES-1 to provide anti-anaphylactic PGE(2). Although iPLA(2)β is partially responsible for PGE(2) production by macrophages and dendritic cells, it is dispensable for mast cell maturation and function.
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Affiliation(s)
- Noriko Ueno
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 256-8506, Japan
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24
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Fakas S, Qiu Y, Dixon JL, Han GS, Ruggles KV, Garbarino J, Sturley SL, Carman GM. Phosphatidate phosphatase activity plays key role in protection against fatty acid-induced toxicity in yeast. J Biol Chem 2011; 286:29074-29085. [PMID: 21708942 DOI: 10.1074/jbc.m111.258798] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The PAH1-encoded phosphatidate (PA) phosphatase in Saccharomyces cerevisiae is a pivotal enzyme that produces diacylglycerol for the synthesis of triacylglycerol (TAG) and simultaneously controls the level of PA used for phospholipid synthesis. Quantitative lipid analysis showed that the pah1Δ mutation caused a reduction in TAG mass and an elevation in the mass of phospholipids and free fatty acids, changes that were more pronounced in the stationary phase. The levels of unsaturated fatty acids in the pah1Δ mutant were unaltered, although the ratio of palmitoleic acid to oleic acid was increased with a similar change in the fatty acid composition of phospholipids. The pah1Δ mutant exhibited classic hallmarks of apoptosis in stationary phase and a marked reduction in the quantity of cytoplasmic lipid droplets. Cells lacking PA phosphatase were sensitive to exogenous fatty acids in the order of toxicity palmitoleic acid > oleic acid > palmitic acid. In contrast, the growth of wild type cells was not inhibited by fatty acid supplementation. In addition, wild type cells supplemented with palmitoleic acid exhibited an induction in PA phosphatase activity and an increase in TAG synthesis. Deletion of the DGK1-encoded diacylglycerol kinase, which counteracts PA phosphatase in controlling PA content, suppressed the defect in lipid droplet formation in the pah1Δ mutant. However, the sensitivity of the pah1Δ mutant to palmitoleic acid was not rescued by the dgk1Δ mutation. Overall, these findings indicate a key role of PA phosphatase in TAG synthesis for protection against fatty acid-induced toxicity.
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Affiliation(s)
- Stylianos Fakas
- Department of Food Science, Rutgers University, New Brunswick, New Jersey 08901; Department of Rutgers Center for Lipid Research, Rutgers University, New Brunswick, New Jersey 08901 and
| | - Yixuan Qiu
- Department of Food Science, Rutgers University, New Brunswick, New Jersey 08901; Department of Rutgers Center for Lipid Research, Rutgers University, New Brunswick, New Jersey 08901 and
| | - Joseph L Dixon
- Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey 08901; Department of Rutgers Center for Lipid Research, Rutgers University, New Brunswick, New Jersey 08901 and
| | - Gil-Soo Han
- Department of Food Science, Rutgers University, New Brunswick, New Jersey 08901; Department of Rutgers Center for Lipid Research, Rutgers University, New Brunswick, New Jersey 08901 and
| | - Kelly V Ruggles
- Department of Pediatrics and Institute of Human Nutrition, Columbia University Medical Center, New York, New York 10032
| | - Jeanne Garbarino
- Department of Pediatrics and Institute of Human Nutrition, Columbia University Medical Center, New York, New York 10032
| | - Stephen L Sturley
- Department of Pediatrics and Institute of Human Nutrition, Columbia University Medical Center, New York, New York 10032
| | - George M Carman
- Department of Food Science, Rutgers University, New Brunswick, New Jersey 08901; Department of Rutgers Center for Lipid Research, Rutgers University, New Brunswick, New Jersey 08901 and.
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25
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Valdearcos M, Esquinas E, Meana C, Gil-de-Gómez L, Guijas C, Balsinde J, Balboa MA. Subcellular localization and role of lipin-1 in human macrophages. THE JOURNAL OF IMMUNOLOGY 2011; 186:6004-13. [PMID: 21478406 DOI: 10.4049/jimmunol.1003279] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The lipins have been described as metabolic enzymes that regulate lipid biosynthesis and also signaling processes by controlling the cellular concentration of bioactive lipids, phosphatidic acid, and diacylgycerol. In the present work we have studied the subcellular localization and role of lipin-1 in human monocyte-derived macrophages. Human macrophages express lipin-1 isoforms α and β. A transfected lipin-1α-enhanced GFP construct associates with membranes of cellular organelles that can be stained with Nile Red. Colocalization experiments with lipid droplet (LD)-specific proteins such as adipophilin/adipose differentiation-related protein/perilipin 2 or TIP47/perilipin 3 show that both proteins colocalize with lipin-1α in the same cellular structures. Reduction of the expression levels of lipin-1 by small interfering RNA technology does not impair triacylglycerol biosynthesis but reduces the size of LDs formed in response to oleic acid. In agreement with these data, peritoneal macrophages from animals that carry a mutation in the Lpin-1 gene (fld animals) also produce less and smaller LDs in response to oleic acid. Mass spectrometry determinations demonstrate that the fatty acid composition of triacylglycerol in isolated LDs from lipin-1-deficient cells differs from that of control cells. Moreover, activation of cytosolic group IVA phospholipase A(2)α, a proinflammatory enzyme that is also involved in LD biogenesis, is also compromised in lipin-1-deficient cells. Collectively, these data suggest that lipin-1 associates with LDs and regulates the activation of cytosolic group IVA phospholipase A(2)α in human monocyte-derived macrophages.
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Affiliation(s)
- Martín Valdearcos
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, 47003 Valladolid, Spain
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26
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Astudillo AM, Pérez-Chacón G, Balgoma D, Gil-de-Gómez L, Ruipérez V, Guijas C, Balboa MA, Balsinde J. Influence of cellular arachidonic acid levels on phospholipid remodeling and CoA-independent transacylase activity in human monocytes and U937 cells. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1811:97-103. [PMID: 21145415 DOI: 10.1016/j.bbalip.2010.11.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 11/15/2010] [Accepted: 11/19/2010] [Indexed: 01/15/2023]
Abstract
The availability of free arachidonic acid (AA) constitutes a limiting step in the synthesis of biologically active eicosanoids. Free AA levels in cells are regulated by a deacylation/reacylation cycle of membrane phospholipids, the so-called Lands cycle, as well as by further remodeling reactions catalyzed by CoA-independent transacylase. In this work, we have comparatively investigated the process of AA incorporation into and remodeling between the various phospholipid classes of human monocytes and monocyte-like U937 cells. AA incorporation into phospholipids was similar in both cell types, but a marked difference in the rate of remodeling was appreciated. U937 cells remodeled AA at a much faster rate than human monocytes. This difference was found not to be related to the differentiation state of the U937 cells, but rather to the low levels of esterified arachidonate found in U937 cells compared to human monocytes. Incubating the U937 cells in AA-rich media increased the cellular content of this fatty acid and led to a substantial decrease of the rate of phospholipid AA remodeling, which was due to reduced CoA-independent transacylase activity. Collectively, these findings provide the first evidence that cellular AA levels determine the amount of CoA-independent transacylase activity expressed by cells and provide support to the notion that CoA-IT is a major regulator of AA metabolism in human monocytes.
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Affiliation(s)
- Alma M Astudillo
- Instituto de Biologia y Genetica Molecular, Consejo Superior de Investigaciones Cientificas, Valladolid, Spain
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27
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Franchi L, Chen G, Marina-Garcia N, Abe A, Qu Y, Bao S, Shayman JA, Turk J, Dubyak GR, Núñez G. Calcium-independent phospholipase A2 beta is dispensable in inflammasome activation and its inhibition by bromoenol lactone. J Innate Immun 2010; 1:607-17. [PMID: 20160900 DOI: 10.1159/000227263] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Calcium-independent phospholipase A2 (iPLA2) has been suggested to play an important role in the activation of caspase-1 induced by lipopolysaccharides (LPS). Here, we used pharmacological and genetic approaches to study the role of iPLA 2 in the activation of caspase-1. Bromoenol lactone (BEL), an inhibitor that was originally used to support a role for iPLA2 in the secretion of IL-1 beta, prevented caspase-1 activation induced by LPS and ATP as described, and also activation triggered by Salmonella infection and cytosolic flagellin, which rely on the Nlrc4 inflammasome. Analysis of BEL enantiomers showed that the S-BEL form was more effective than R-BEL in inhibiting the inflammasome, suggesting a role for iPLA2 . However, caspase-1 activation and IL-1 beta secretion and their inhibition by BEL were unimpaired in macrophages deficient in iPLA2 beta. BEL was originally identified as an inhibitor of serine proteases. Consistent with the latter, the serine proteases inhibitors TPCK, TLCK and AAF-cmk prevented the activation of the Nlrc4 and Nlrp3 inflammasomes while pan-cathepsin inhibitors were ineffective. These results indicate that iPLA2 beta is not critical for caspase-1 activation as currently proposed. Instead, the results suggest that serine protease(s) targeted by BEL may play a critical role in the activation of the inflammasome triggered by microbial stimuli.
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Affiliation(s)
- Luigi Franchi
- Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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28
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Balgoma D, Astudillo AM, Pérez-Chacón G, Montero O, Balboa MA, Balsinde J. Markers of monocyte activation revealed by lipidomic profiling of arachidonic acid-containing phospholipids. THE JOURNAL OF IMMUNOLOGY 2010; 184:3857-65. [PMID: 20181887 DOI: 10.4049/jimmunol.0902883] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Stimulated human monocytes undergo an intense trafficking of arachidonic acid (AA) among glycerophospholipidclasses. Using HPLC coupled to electrospray ionization mass spectrometry, we have characterized changes in the levels of AA-containing phospholipid species in human monocytes. In resting cells, AA was found esterified into various molecular species of phosphatidylinositol (PI), choline glycerophospholipids (PCs), and ethanolamine glycerophospholipids (PEs). All major AA-containing PC and PI molecular species decreased in zymosan-stimulated cells; however, no PE molecular species was found to decrease. In contrast, the levels of three AA-containing species increased in zymosan-activated cells compared with resting cells: 1,2-diarachidonyl-glycero-3-phosphoinositol [PI(20:4/20:4)]; 1,2-diarachidonyl-glycero-3-phosphocholine [PC(20:4/20:4)]; and 1-palmitoleoyl-2-arachidonyl-glycero-3-phosphoethanolamine [PE(16:1/20:4)]. PI(20:4/20:4) and PC(20:4/20:4), but not PE(16:1/20:4), also significantly increased when platelet-activating factor or PMA were used instead of zymosan to stimulate the monocytes. Analysis of the pathways involved in the synthesis of these three lipids suggest that PI(20:4/20:4) and PC(20:4/20:4) were produced in a deacylation/reacylation pathway via acyl-CoA synthetase-dependent reactions, whereas PE(16:1/20:4) was generated via a CoA-independent transacylation reaction. Collectively, our results define the increases in PI(20:4/20:4) and PC(20:4/20:4) as lipid metabolic markers of human monocyte activation and establish lipidomics as a powerful tool for cell typing under various experimental conditions.
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Affiliation(s)
- David Balgoma
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Valladolid, Spain
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Xie Z, Gong MC, Su W, Xie D, Turk J, Guo Z. Role of calcium-independent phospholipase A2beta in high glucose-induced activation of RhoA, Rho kinase, and CPI-17 in cultured vascular smooth muscle cells and vascular smooth muscle hypercontractility in diabetic animals. J Biol Chem 2010; 285:8628-38. [PMID: 20086008 DOI: 10.1074/jbc.m109.057711] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Previous studies suggest that high glucose-induced RhoA/Rho kinase/CPI-17 activation is involved in diabetes-associated vascular smooth muscle hypercontractility. However, the upstream signaling that links high glucose and RhoA/Rho kinase/CPI-17 activation is unknown. Here we report that calcium-independent phospholipase A(2)beta (iPLA(2)beta) is required for high glucose-induced RhoA/Rho kinase/CPI-17 activation and thereby contributes to diabetes-associated vascular smooth muscle hypercontractility. We demonstrate that high glucose increases iPLA(2)beta mRNA, protein, and iPLA(2) activity in a time-dependent manner. Protein kinase C is involved in high glucose-induced iPLA(2)beta protein up-regulation. Inhibiting iPLA(2)beta activity with bromoenol lactone or preventing its expression by genetic deletion abolishes high glucose-induced RhoA/Rho kinase/CPI-17 activation, and restoring expression of iPLA(2)beta in iPLA(2)beta-deficient cells also restores high glucose-induced CPI-17 phosphorylation. Pharmacological and genetic inhibition of 12/15-lipoxygenases has effects on high glucose-induced CPI-17 phosphorylation similar to iPLA(2)beta inhibition. Moreover, increases in iPLA(2) activity and iPLA(2)beta protein expression are also observed in both type 1 and type 2 diabetic vasculature. Pharmacological and genetic inhibition of iPLA(2)beta, but not iPLA(2)gamma, diminishes diabetes-associated vascular smooth muscle hypercontractility. In summary, our results reveal a novel mechanism by which high glucose-induced, protein kinase C-mediated iPLA(2)beta up-regulation activates the RhoA/Rho kinase/CPI-17 via 12/15-lipoxygenases and thereby contributes to diabetes-associated vascular smooth muscle hypercontractility.
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Affiliation(s)
- Zhongwen Xie
- Department of Physiology, University of Kentucky School of Medicine, Lexington, Kentucky 40536, USA
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Lei X, Barbour SE, Ramanadham S. Group VIA Ca2+-independent phospholipase A2 (iPLA2beta) and its role in beta-cell programmed cell death. Biochimie 2010; 92:627-37. [PMID: 20083151 DOI: 10.1016/j.biochi.2010.01.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Accepted: 01/11/2010] [Indexed: 01/09/2023]
Abstract
Activation of phospholipases A(2) (PLA(2)s) leads to the generation of biologically active lipid mediators that can affect numerous cellular events. The Group VIA Ca(2+)-independent PLA(2), designated iPLA(2)beta, is active in the absence of Ca(2+), activated by ATP, and inhibited by the bromoenol lactone suicide inhibitor (BEL). Over the past 10-15 years, studies using BEL have demonstrated that iPLA(2)beta participates in various biological processes and the recent availability of mice in which iPLA(2)beta expression levels have been genetically-modified are extending these findings. Work in our laboratory suggests that iPLA(2)beta activates a unique signaling cascade that promotes beta-cell apoptosis. This pathway involves iPLA(2)beta dependent induction of neutral sphingomyelinase, production of ceramide, and activation of the intrinsic pathway of apoptosis. There is a growing body of literature supporting beta-cell apoptosis as a major contributor to the loss of beta-cell mass associated with the onset and progression of Type 1 and Type 2 diabetes mellitus. This underscores a need to gain a better understanding of the molecular mechanisms underlying beta-cell apoptosis so that improved treatments can be developed to prevent or delay the onset and progression of diabetes mellitus. Herein, we offer a general review of Group VIA Ca(2+)-independent PLA(2) (iPLA(2)beta) followed by a more focused discussion of its participation in beta-cell apoptosis. We suggest that iPLA(2)beta-derived products trigger pathways which can lead to beta-cell apoptosis during the development of diabetes.
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Affiliation(s)
- Xiaoyong Lei
- Department of Medicine, Mass Spectrometry Resource and Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, MO 63110, USA
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Ayilavarapu S, Kantarci A, Fredman G, Turkoglu O, Omori K, Liu H, Iwata T, Yagi M, Hasturk H, Van Dyke TE. Diabetes-induced oxidative stress is mediated by Ca2+-independent phospholipase A2 in neutrophils. THE JOURNAL OF IMMUNOLOGY 2010; 184:1507-15. [PMID: 20053941 DOI: 10.4049/jimmunol.0901219] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Neutrophils from people with poorly controlled diabetes present a primed phenotype and secrete excessive superoxide. Phospholipase A(2) (PLA(2))-derived arachidonic acid (AA) activates the assembly of NADPH oxidase to generate superoxide anion. There is a gap in the current literature regarding which PLA(2) isoform regulates NADPH oxidase activation. The aim of this study was to identify the PLA(2) isoform involved in the regulation of superoxide generation in neutrophils and investigate if PLA(2) mediates priming in response to pathologic hyperglycemia. Neutrophils were isolated from people with diabetes mellitus and healthy controls, and HL60 neutrophil-like cells were grown in hyperglycemic conditions. Incubating neutrophils with the Ca(2+)-independent PLA(2) (iPLA(2)) inhibitor bromoenol lactone (BEL) completely suppressed fMLP-induced generation of superoxide. The nonspecific actions of BEL on phosphatidic acid phosphohydrolase-1, p47(phox) phosphorylation, and apoptosis were ruled out by specific assays. Small interfering RNA knockdown of iPLA(2) inhibited superoxide generation by neutrophils. Neutrophils from people with poorly controlled diabetes and in vitro incubation of neutrophils with high glucose and the receptor for advanced glycation end products ligand S100B greatly enhanced superoxide generation compared with controls, and this was significantly inhibited by BEL. A modified iPLA(2) assay, Western blotting, and PCR confirmed that there was increased iPLA(2) activity and expression in neutrophils from people with diabetes. AA (10 microM) partly rescued the inhibition of superoxide generation mediated by BEL, confirming that NADPH oxidase activity is, in part, regulated by AA. This study provides evidence for the role of iPLA(2) in enhanced superoxide generation in neutrophils from people with diabetes mellitus and presents an alternate pathway independent of protein kinase C and phosphatidic acid phosphohydrolase-1 hydrolase signaling.
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Affiliation(s)
- Srinivas Ayilavarapu
- Department of Periodontology and Oral Biology, Goldman School of Dental Medicine, Boston University, Boston, MA 02118, USA
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De-Paula VJ, Schaeffer EL, Talib LL, Gattaz WF, Forlenza OV. Inhibition of phospholipase A2 increases tau phosphorylation at Ser214 in embryonic rat hippocampal neurons. Prostaglandins Leukot Essent Fatty Acids 2010; 82:57-60. [PMID: 19726172 DOI: 10.1016/j.plefa.2009.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 07/30/2009] [Accepted: 07/31/2009] [Indexed: 11/21/2022]
Abstract
BACKGROUND Arachidonic acid is released from cellular membranes by the action of phospholipase A(2) (PLA(2)) and is implicated in microtubule-associated protein Tau phosphorylation. Tau hyperphosphorylation affects its ability to stabilize microtubules. OBJECTIVE To determine the effect of PLA(2) inhibition on the phosphorylation state of Tau phosphoepitopes in primary cultures of hippocampal neurons. METHODS 4 DIC neurons were incubated at different concentrations of methyl-arachidonylfluorophosphonate (MAFP), an irreversible inhibitor of cPLA(2) and iPLA(2). Changes on Tau phosphorylation were determined by Western blotting with a panel of anti-Tau antibodies (C-terminal, Ser199/202, Ser202/205, Ser396 and Ser214). RESULTS The Ser214 site was hyperphosphorylated upon MAFP treatment. Significant differences were observed with 10 microM (p=0.01), 50 microM (p=0.01) and 100 microM (p=0.05) of MAFP. Less-intense changes were found in other phosphoepitopes. CONCLUSION The present findings indicate that the phosphorylation of Ser214 is regulated by c- and/or iPLA(2), whereas other phosphoepitopes primarily regulated by GKS3b were not affected.
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Affiliation(s)
- Vanessa J De-Paula
- Laboratory of Neuroscience LIM-27, Department and Institute of Psychiatry, Faculty of Medicine, University of Sao Paulo, Brazil
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Pérez-Chacón G, Astudillo AM, Ruipérez V, Balboa MA, Balsinde J. Signaling role for lysophosphatidylcholine acyltransferase 3 in receptor-regulated arachidonic acid reacylation reactions in human monocytes. THE JOURNAL OF IMMUNOLOGY 2009; 184:1071-8. [PMID: 20018618 DOI: 10.4049/jimmunol.0902257] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cellular availability of free arachidonic acid (AA) is an important step in the production of pro- and anti-inflammatory eicosanoids. Control of free AA levels in cells is carried out by the action of phospholipase A2s and lysophospholipid acyltransferases, which are responsible for the reactions of deacylation and incorporation of AA from and into the sn-2 position of phospholipids, respectively. In this work, we have examined the pathways for AA incorporation into phospholipids in human monocytes stimulated by zymosan. Our data show that stimulated cells exhibit an enhanced incorporation of AA into phospholipids that is not secondary to an increased availability of lysophospholipid acceptors due to phospholipase A2 activation but rather reflects the receptor-regulated nature of the AA reacylation pathway. In vitro activity measurements indicate that the receptor-sensitive step of the AA reacylation pathway is the acyltransferase using lysophosphatidylcholine (lysoPC) as acceptor, and inhibition of the enzyme lysoPC acyltransferase 3 by specific small interfering RNA results in inhibition of the stimulated incorporation of AA into phospholipids. Collectively, these results define lysoPC acyltransferase 3 as a novel-signal-regulated enzyme that is centrally implicated in limiting free AA levels in activated cells.
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Affiliation(s)
- Gema Pérez-Chacón
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Valladolid, Spain
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Pérez-Chacón G, Astudillo AM, Balgoma D, Balboa MA, Balsinde J. Control of free arachidonic acid levels by phospholipases A2 and lysophospholipid acyltransferases. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:1103-13. [DOI: 10.1016/j.bbalip.2009.08.007] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 08/17/2009] [Accepted: 08/18/2009] [Indexed: 12/11/2022]
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Grkovich A, Dennis EA. Phosphatidic acid phosphohydrolase in the regulation of inflammatory signaling. ACTA ACUST UNITED AC 2009; 49:114-20. [PMID: 19534028 DOI: 10.1016/j.advenzreg.2009.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Andrej Grkovich
- Department of Chemistry and Biochemistry and Department of Pharmacology, School of Medicine, University of California at San Diego, La Jolla, CA 92093-0601, USA
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36
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Zachman DK, Chicco AJ, McCune SA, Murphy RC, Moore RL, Sparagna GC. The role of calcium-independent phospholipase A2 in cardiolipin remodeling in the spontaneously hypertensive heart failure rat heart. J Lipid Res 2009; 51:525-34. [PMID: 19741254 DOI: 10.1194/jlr.m000646] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Cardiolipin (CL) is an essential phospholipid component of the inner mitochondrial membrane. In the mammalian heart, the functional form of CL is tetralinoleoyl CL [(18:2)(4)CL]. A decrease in (18:2)(4)CL content, which is believed to negatively impact mitochondrial energetics, occurs in heart failure (HF) and other mitochondrial diseases. Presumably, (18:2)(4)CL is generated by remodeling nascent CL in a series of deacylation-reacylation cycles; however, our overall understanding of CL remodeling is not yet complete. Herein, we present a novel cell culture method for investigating CL remodeling in myocytes isolated from Spontaneously Hypertensive HF rat hearts. Further, we use this method to examine the role of calcium-independent phospholipase A(2) (iPLA(2)) in CL remodeling in both HF and nonHF cardiomyocytes. Our results show that 18:2 incorporation into (18:2)(4)CL is: a) performed singly with respect to each fatty acyl moiety, b) attenuated in HF relative to nonHF, and c) partially sensitive to iPLA(2) inhibition by bromoenol lactone. These results suggest that CL remodeling occurs in a step-wise manner, that compromised 18:2 incorporation contributes to a reduction in (18:2)(4)CL in the failing rat heart, and that mitochondrial iPLA(2) plays a role in the remodeling of CL's acyl composition.
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Affiliation(s)
- Derek K Zachman
- Department of Integrative Physiology, University of Colorado Cardiovascular Institute, University of Colorado at Boulder, Boulder, CO 80309-0354, USA
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McElroy SP, Drummond RM, Gurney AM. Regulation of store-operated Ca2+ entry in pulmonary artery smooth muscle cells. Cell Calcium 2009; 46:99-106. [DOI: 10.1016/j.ceca.2009.05.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 05/05/2009] [Accepted: 05/31/2009] [Indexed: 11/25/2022]
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Singaravelu K, Lohr C, Deitmer JW. Calcium-independent phospholipase A2 mediates store-operated calcium entry in rat cerebellar granule cells. THE CEREBELLUM 2009; 7:467-81. [PMID: 18784973 DOI: 10.1007/s12311-008-0050-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Store-operated Ca(2+) entry (SOCE) has been extensively studied in non-neuronal cells, such as glial cells and smooth muscle cells, in which Ca(2+)-independent phospholipase A(2) (iPLA(2)) has been shown to play a key role in the regulation of SOCE channels. In the present study, we have investigated the role of iPLA(2) for store-operated Ca(2+) entry in rat cerebellar granule neurons in acute brain slices using confocal Ca(2+) imaging. Depletion of Ca(2+) stores by cyclopiazonic acid (CPA) induced a Ca(2+) influx, which could be inhibited by SOCE channel blockers 2-aminoethoxy-diphenylborate (2-APB) and 3,5-bistrifluoromethyl pyrazole derivative (BTP2), but not by the voltage-operated Ca(2+) channel blocker diltiazem and by the Na+ channel blocker tetrodotoxin. The inhibitors of iPLA(2), bromoenol lactone (BEL) and 1,1,1-trifluoro-2-heptadecanone, and the selective suppression of iPLA(2) expression by antisense oligodeoxynucleotides, inhibited CPA-induced Ca(2+) influx. Calmidazolium, which relieves the block of inhibitory calmodulin from iPLA(2), elicited a Ca(2+) influx similar to CPA-induced Ca(2+) entry. The product of iPLA(2), lysophosphatidylinositol, elicited a 2-APB- and BTP2-sensitive, but BEL-insensitive, Ca(2+) influx. Spontaneous Ca(2+) oscillations in granule cells in acute brain slices were reduced after inhibiting iPLA(2) activity or by blocking SOCE channels. The results suggest that depletion of Ca(2+) stores activates iPLA(2) to trigger Ca(2+) influx by the formation of lysophospholipids in these neurons.
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Ruipérez V, Astudillo AM, Balboa MA, Balsinde J. Coordinate regulation of TLR-mediated arachidonic acid mobilization in macrophages by group IVA and group V phospholipase A2s. THE JOURNAL OF IMMUNOLOGY 2009; 182:3877-83. [PMID: 19265167 DOI: 10.4049/jimmunol.0804003] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Macrophages can be activated through TLRs for a variety of innate immune responses. In contrast with the wealth of data existing on TLR-dependent gene expression and resultant cytokine production, very little is known on the mechanisms governing TLR-mediated arachidonic acid (AA) mobilization and subsequent eicosanoid production. We have previously reported the involvement of both cytosolic group IVA phospholipase A(2) (cPLA(2)) and secreted group V phospholipase A(2) (sPLA(2)-V) in regulating the AA mobilization response of macrophages exposed to bacterial LPS, a TLR4 agonist. In the present study, we have used multiple TLR agonists to define the role of various PLA(2)s in macrophage AA release via TLRs. Activation of P388D(1) and RAW2647.1 macrophage-like cells via TLR1/2, TLR2, TLR3, TLR4, TLR6/2, and TLR7, but not TLR5 or TLR9, resulted in AA mobilization that appears to involve the activation of both cPLA(2) and sPLA(2) but not of calcium-independent phospholipase A(2). Furthermore, inhibition of sPLA(2)-V by RNA interference or by two cell-permeable compounds, namely scalaradial and manoalide, resulted in a marked reduction of the phosphorylation of ERK1/2 and cPLA(2) via TLR1/2, TLR2, TLR3, and TLR4, leading to attenuated AA mobilization. Collectively, the results suggest a model whereby sPLA(2)-V contributes to the macrophage AA mobilization response via various TLRs by amplifying cPLA(2) activation through the ERK1/2 phosphorylation cascade.
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Affiliation(s)
- Violeta Ruipérez
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Valladolid, Spain
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Andersen AD, Poulsen KA, Lambert IH, Pedersen SF. HL-1 mouse cardiomyocyte injury and death after simulated ischemia and reperfusion: roles of pH, Ca2+-independent phospholipase A2, and Na+/H+ exchange. Am J Physiol Cell Physiol 2009; 296:C1227-42. [PMID: 19261908 DOI: 10.1152/ajpcell.00370.2008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The Ca(2+)-independent phospholipase A(2) VI (iPLA(2)-VI) and the Na(+)/H(+) exchanger isoform 1 (NHE1) are highly pH-sensitive proteins that exert both protective and detrimental effects in cardiac ischemia-reperfusion. Here, we investigated the role of extracellular pH (pH(o)) in ischemia-reperfusion injury and death and in regulation and function of iPLA(2)-VI and NHE1 under these conditions. HL-1 cardiomyocytes were exposed to simulated ischemia (SI; 0.5% O(2), 8 mM K(+), and 20 mM lactate) at pH(o) 6.0 and 7.4, with or without 4 or 8 h of reperfusion (SI/R). Cytochrome c release and caspase-3 activation were reduced after acidic compared with neutral SI, whereas necrotic death, estimated as glucose-6-phosphate dehydrogenase release, was similar in the two conditions. Inhibition of iPLA(2)-VI activity by bromoenol lactone (BEL) elicited cardiomyocyte necrosis during normoxia and after acidic, yet not after neutral, SI. The isoform-selective enantiomers R- and S-BEL both mimicked the effect of racemic BEL after acidic SI. In contrast, inhibition of NHE activity by EIPA had no significant effect on necrosis after SI. Both neutral and acidic SI were associated with a reversible loss of F-actin and cortactin integrity. Inhibition of iPLA(2)-VI disrupted F-actin, cortactin, and mitochondrial integrity, whereas inhibition of NHE slightly reduced stress fiber content. iPLA(2)-VIA and NHE1 mRNA levels were reduced during SI and upregulated in a pH(o)-dependent manner during SI/R. This also affected the subcellular localization of iPLA(2)-VIA. Thus, the mode of cell death and the roles and regulation of iPLA(2)-VI and NHE1 are at least in part determined by the pH(o) during SI. In addition to having clinically relevant implications, these findings can in part explain the contradictory results obtained from previous studies of iPLA(2)-VIA and NHE1 during cardiac I/R.
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Affiliation(s)
- Ann-Dorit Andersen
- Department of Biology, Univesity of Copenhagen, DK-2100 Copenhagen, Denmark
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41
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Herrero AB, Astudillo AM, Balboa MA, Cuevas C, Balsinde J, Moreno S. Levels of SCS7/FA2H-mediated fatty acid 2-hydroxylation determine the sensitivity of cells to antitumor PM02734. Cancer Res 2009; 68:9779-87. [PMID: 19047157 DOI: 10.1158/0008-5472.can-08-1981] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PM02734 is a novel synthetic antitumor drug that is currently in phase I clinical trials. To gain some insight into its mode of action, we used the yeast Saccharomyces cerevisiae as a model system. Treatment of S. cerevisiae with PM02734 rapidly induced necrosis-like cell death, as also found for mammalian cells treated with its close analogue kahalalide F. We have screened the complete set of 4,848 viable S. cerevisiae haploid deletion mutants to identify genes involved in sensitivity or resistance to PM02734. Forty-five percent of the 40 most sensitive strains identified had a role in intracellular vesicle trafficking, indicating that the drug severely affects this process. A mutant strain lacking the sphingolipid fatty acyl 2-hydroxylase Scs7 was found to be the most resistant to PM02734, whereas overexpression of Scs7 rendered the cells hypersensitive to PM02734. To validate these findings in human cells, we did small interfering RNA experiments and also overexpressed the Scs7 human homologue FA2H in human cancer cell lines. As in yeast, FA2H silencing turned the cells resistant to the drug, whereas FA2H overexpression led to an increased sensitivity. Moreover, exogenous addition of the 2-hydroxylated fatty acid 2-hydroxy palmitic acid to different human cell lines increased their sensitivity to the cytotoxic compound. Taken together, these results suggest that the cell membrane and, in particular, 2-hydroxy fatty acid-containing ceramides are important for PM02734 activity. These findings may have important implications in the development of PM02734 because tumor cells with high FA2H expression are expected to be particularly sensitive to this drug.
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Affiliation(s)
- Ana B Herrero
- Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
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Gubern A, Barceló-Torns M, Casas J, Barneda D, Masgrau R, Picatoste F, Balsinde J, Balboa MA, Claro E. Lipid droplet biogenesis induced by stress involves triacylglycerol synthesis that depends on group VIA phospholipase A2. J Biol Chem 2008; 284:5697-708. [PMID: 19117952 DOI: 10.1074/jbc.m806173200] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
This work investigates the metabolic origin of triacylglycerol (TAG) formed during lipid droplet (LD) biogenesis induced by stress. Cytotoxic inhibitors of fatty acid synthase induced TAG synthesis and LD biogenesis in CHO-K1 cells, in the absence of external sources of fatty acids. TAG synthesis was required for LD biogenesis and was sensitive to inhibition and down-regulation of the expression of group VIA phospholipase A(2) (iPLA(2)-VIA). Induction of stress with acidic pH, C(2)-ceramide, tunicamycin, or deprivation of glucose also stimulated TAG synthesis and LD formation in a manner dependent on iPLA(2)-VIA. Overexpression of the enzyme enhanced TAG synthesis from endogenous fatty acids and LD occurrence. During stress, LD biogenesis but not TAG synthesis required phosphorylation and activation of group IVA PLA(2) (cPLA(2)alpha). The results demonstrate that iPLA(2)-VIA provides fatty acids for TAG synthesis while cPLA(2)alpha allows LD biogenesis. LD biogenesis during stress may be a survival strategy, recycling structural phospholipids into energy-generating substrates.
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Affiliation(s)
- Albert Gubern
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona (UAB), Edifici M2, Campus de la UAB, Barcelona E-08193, Spain
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Balgoma D, Montero O, Balboa MA, Balsinde J. Calcium-independent phospholipase A2-mediated formation of 1,2-diarachidonoyl-glycerophosphoinositol in monocytes. FEBS J 2008; 275:6180-91. [PMID: 19016853 DOI: 10.1111/j.1742-4658.2008.06742.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phagocytic cells exposed to exogenous arachidonic acid (AA) incorporate large quantities of this fatty acid into choline and ethanolamine glycerophospholipids, and into phosphatidylinositol (PtdIns). Utilizing liquid chromatography coupled to MS, we have characterized the incorporation of exogenous deuterated AA ([(2)H]AA) into specific PtdIns molecular species in human monocyte cells. A PtdIns species containing two exogenous [(2)H]AA molecules (1-[(2)H]AA-2-[(2)H]AA-glycero-3-phosphoinositol) was readily detected when human U937 monocyte-like cells and peripheral blood monocytes were exposed to [(2)H]AA concentrations as low as 160 nm to 1 mum. Bromoenol lactone, an inhibitor of Ca(2+)-independent phospholipase A(2) (iPLA(2)), diminished lyso-PtdIns levels, and almost completely inhibited the appearance of 1-[(2)H]AA-2-[(2)H]AA-glycero-3-phosphoinositol, suggesting the involvement of deacylation reactions in the synthesis of this phospholipid. De novo synthesis did not appear to be involved, as no other diarachidonoyl phospholipid or neutral lipid was detected under these conditions. Measurement of the metabolic fate of 1-[(2)H]AA-2-[(2)H]AA-glycero-3-phosphoinositol after pulse-labeling of the cells with [(2)H]AA showed a time-dependent, exponential decrease in the level of this phospholipid. These results identify 1-[(2)H]AA-2-[(2)H]AA-glycero-3-phosphoinositol as a novel, short-lived species for the initial incorporation of AA into the PtdIns class of cellular phospholipids in human monocytes.
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Affiliation(s)
- David Balgoma
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Valladolid, Spain
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Theofilopoulos S, Lykidis A, Leondaritis G, Mangoura D. Novel function of the human presqualene diphosphate phosphatase as a type II phosphatidate phosphatase in phosphatidylcholine and triacylglyceride biosynthesis pathways. Biochim Biophys Acta Mol Cell Biol Lipids 2008; 1781:731-42. [DOI: 10.1016/j.bbalip.2008.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Revised: 08/29/2008] [Accepted: 09/11/2008] [Indexed: 11/27/2022]
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45
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Moon SH, Jenkins CM, Mancuso DJ, Turk J, Gross RW. Smooth muscle cell arachidonic acid release, migration, and proliferation are markedly attenuated in mice null for calcium-independent phospholipase A2beta. J Biol Chem 2008; 283:33975-87. [PMID: 18927078 DOI: 10.1074/jbc.m805817200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pharmacologic evidence suggests that the lipid products generated by one or more calcium-independent phospholipases A(2) (iPLA(2)s) participate in the regulation of vascular tone through smooth muscle cell (SMC) Ca(2+) signaling and the release of arachidonic acid. However, the recent identification of new members of the iPLA(2) family, each inhibitable by (E)-6-(bromomethylene)-3-(1-naphthalenyl)-2H-tetrahydropyran-2-one, has rendered definitive identification of the specific enzyme(s) mediating these processes difficult. Accordingly, we used iPLA(2)beta(-/-) mice to demonstrate that iPLA(2)beta is responsible for the majority of thapsigargin and ionophore (A23187)-induced arachidonic acid release from SMCs. Both thapsigargin and A23187 stimulated robust [(3)H]arachidonate (AA) release from wild-type aortic SMCs that was dramatically attenuated in iPLA(2)beta(-/-) mice (>80% reduction at 5 min; p < 0.01). Moreover, iPLA(2)beta(-/-) mice displayed defects in SMC Ca(2+) homeostasis and decreased SMC migration and proliferation in a model of vascular injury. Ca(2+)-store depletion resulted in the rapid entry of external Ca(2+) into wild-type aortic SMCs that was significantly slower in iPLA(2)beta-null cells (p < 0.01). Furthermore, SMCs from iPLA(2)beta-null mesenteric arterial explants demonstrated decreased proliferation and migration. The defects in migration and proliferation in iPLA(2)beta-null SMCs were restored by 2 mum AA. Remarkably, the cyclooxygenase-2-specific inhibitor, NS-398, prevented AA-induced rescue of SMC migration and proliferation in iPLA(2)beta(-/-) mice. Moreover, PGE(2) alone rescued proliferation and migration in iPLA(2)beta(-/-) mice. We conclude that iPLA(2)beta is an important mediator of AA release and prostaglandin E(2) production in SMCs, modulating vascular tone, cellular signaling, proliferation, and migration.
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Affiliation(s)
- Sung Ho Moon
- Division of Bioorganic Chemistry and Molecular Pharmacology, Endocrinology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Kurusu S, Matsui K, Watanabe T, Tsunou T, Kawaminami M. The cytotoxic effect of bromoenol lactone, a calcium-independent phospholipase A2 inhibitor, on rat cortical neurons in culture. Cell Mol Neurobiol 2008; 28:1109-18. [PMID: 18528752 DOI: 10.1007/s10571-008-9287-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Accepted: 05/20/2008] [Indexed: 12/30/2022]
Abstract
This study characterized the phospholipase A(2) (PLA(2)) activity in cerebral cortex of fetal rat brain and investigated effects of chemical inhibition of Ca(2+)-independent PLA(2) (iPLA(2)) on neurite outgrowth and cell development of cortical neurons in vitro. The PLA(2) activity in fetal brain was insensitive to a Ca(2+)-chelator EGTA and was significantly impaired by an iPLA(2) inhibitor, bromoenol lactone (BEL). Following treatment with BEL, cortical neurons showed acute loss of neurites and impaired cell body, which were clearly dose- and time-dependent. Nuclear staining revealed nuclear regression (shrinkage), but not fragmentation, in BEL-treated cells. The cytotoxic effect of BEL was additive with arachidonic acid (AA) and AA alone also induced neurite demise. BEL treatment resulted in increased production of prostaglandin E(2). Overall data suggest that iPLA(2), a primary PLA(2) isoform in cerebral cortex, displays a housekeeping role in development and neurite outgrowth in cortical neurons in vitro probably via maintaining phospholipid membrane remodeling rather than generating free fatty acids and lysophospholipids.
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Affiliation(s)
- Shiro Kurusu
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine, Towada, Aomori 034-8628, Japan.
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Sun B, Zhang X, Talathi S, Cummings BS. Inhibition of Ca2+-Independent Phospholipase A2 Decreases Prostate Cancer Cell Growth by p53-Dependent and Independent Mechanisms. J Pharmacol Exp Ther 2008; 326:59-68. [DOI: 10.1124/jpet.108.138958] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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Balboa MA, Pérez R, Balsinde J. Calcium-independent phospholipase A2 mediates proliferation of human promonocytic U937 cells. FEBS J 2008; 275:1915-24. [DOI: 10.1111/j.1742-4658.2008.06350.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Shimizu M, Matsumoto Y, Kurosawa T, Azuma C, Enomoto M, Nakamura H, Hirabayashi T, Kaneko M, Okuma Y, Murayama T. Release of arachidonic acid induced by tumor necrosis factor-alpha in the presence of caspase inhibition: evidence for a cytosolic phospholipase A2alpha-independent pathway. Biochem Pharmacol 2007; 75:1358-69. [PMID: 18191813 DOI: 10.1016/j.bcp.2007.11.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Revised: 11/16/2007] [Accepted: 11/29/2007] [Indexed: 01/17/2023]
Abstract
Stimulation of L929 cells with tumor necrosis factor-alpha (TNFalpha) caused cell death accompanied by a release of arachidonic acid (AA). Although the inhibition of caspases has been shown to cause necrosis in TNFalpha-treated L929 cells, its role in the TNFalpha-induced release of AA has not been elucidated. The release of AA is tightly regulated by phospholipase A(2) (PLA(2)). To find out the mechanisms underlying the TNFalpha-induced release of AA, we investigated the relationship between TNFalpha stimulation and PLA(2) regulation with and without zVAD, an inhibitor of caspases. In the present study, we found that treatment with TNFalpha and zVAD stimulated release of AA and cell death in C12 cells (a variant of L929 cells lacking alpha type of cytosolic PLA(2) (cPLA(2)alpha)). Stimulation with TNFalpha/zVAD also caused the release of AA from L929-cPLA(2)alpha-siRNA cells. Treatment with pyrrophenone (a selective inhibitor of cPLA(2)alpha) completely inhibited the TNFalpha-induced release of AA, but only partially inhibited the TNFalpha/zVAD-induced response in L929 cells. The TNFalpha/zVAD-induced release of AA from C12 and L929-cPLA(2)alpha-siRNA cells was pyrrophenone-insensitive, but inhibited by treatment with butylated hydroxyanisole (BHA, an antioxidant). Treatment with dithiothreitol, which inactivates secretory PLA(2) activity, decreased the amount of AA released by TNFalpha/zVAD. TNFalpha/zVAD appears to stimulate release of AA from C12 cells in a cPLA(2)alpha-independent, BHA-sensitive manner. The possible roles of secretory PLA(2) and reactive oxygen species from different pools in the release of AA and cell death were discussed.
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Affiliation(s)
- Masaya Shimizu
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675, Japan
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Pindado J, Balsinde J, Balboa MA. TLR3-dependent induction of nitric oxide synthase in RAW 264.7 macrophage-like cells via a cytosolic phospholipase A2/cyclooxygenase-2 pathway. THE JOURNAL OF IMMUNOLOGY 2007; 179:4821-8. [PMID: 17878381 DOI: 10.4049/jimmunol.179.7.4821] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
dsRNA is a by-product of viral replication capable of inducing an inflammatory response when recognized by phagocyte cells. In this study, we identify group IVA cytosolic phospholipase A2 (cPLA2alpha) as an effector of the antiviral response. Treatment of RAW 264.7 murine macrophage-like cells with the dsRNA analog polyinosinic:polycytidylic acid (poly-IC) promotes the release of free arachidonic acid that is subsequently converted into PGE2 by the de novo-synthesized cyclooxygenase-2 (COX-2) enzyme. These processes are blocked by the selective cPLA2alpha inhibitor pyrrophenone, pointing out to cPLA2alpha as the effector involved. In keeping with this observation, the cPLA2alpha phosphorylation state increases after cellular treatment with poly-IC. Inhibition of cPLA2alpha expression and activity by either small interfering RNA (siRNA) or pyrrophenone leads to inhibition of the expression of the inducible NO synthase (iNOS) gene. Moreover, COX-2-derived PGE2 production appears to participate in iNOS expression, because siRNA inhibition of COX-2 also leads to inhibition of iNOS, the latter of which is restored by exogenous addition of PGE2. Finally, cellular depletion of TLR3 by siRNA inhibits COX-2 expression, PGE2 generation, and iNOS induction by poly-IC. Collectively, these findings suggest a model for macrophage activation in response to dsRNA, whereby engagement of TLR3 leads to cPLA2alpha-mediated arachidonic acid mobilization and COX-2-mediated PGE2 production, which cooperate to induce the expression of iNOS.
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Affiliation(s)
- José Pindado
- Institute of Molecular Biology and Genetics, Spanish National Research Council and University of Valladolid School of Medicine, Valladolid, Spain
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