101
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Phospholipase A 2 catalysis and lipid mediator lipidomics. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:766-771. [PMID: 30905345 DOI: 10.1016/j.bbalip.2018.08.010] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/10/2018] [Accepted: 08/16/2018] [Indexed: 01/09/2023]
Abstract
Phospholipase A2 (PLA2) enzymes are the upstream regulators of the eicosanoid pathway liberating free arachidonic acid from the sn-2 position of membrane phospholipids. Free intracellular arachidonic acid serves as a substrate for the eicosanoid biosynthetic enzymes including cyclooxygenases, lipoxygenases, and cytochrome P450s that lead to inflammation. The Group IVA cytosolic (cPLA2), Group VIA calcium-independent (iPLA2), and Group V secreted (sPLA2) are three well-characterized human enzymes that have been implicated in eicosanoid formation. In this review, we will introduce and summarize the regulation of catalytic activity and cellular localization, structural characteristics, interfacial activation and kinetics, substrate specificity, inhibitor binding and interactions, and the downstream implications for eicosanoid biosynthesis of these three important PLA2 enzymes.
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102
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Chiu CC, Lu CS, Weng YH, Chen YL, Huang YZ, Chen RS, Cheng YC, Huang YC, Liu YC, Lai SC, Lin KJ, Lin YW, Chen YJ, Chen CL, Yeh TH, Wang HL. PARK14 (D331Y) PLA2G6 Causes Early-Onset Degeneration of Substantia Nigra Dopaminergic Neurons by Inducing Mitochondrial Dysfunction, ER Stress, Mitophagy Impairment and Transcriptional Dysregulation in a Knockin Mouse Model. Mol Neurobiol 2018; 56:3835-3853. [PMID: 30088174 DOI: 10.1007/s12035-018-1118-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 05/11/2018] [Indexed: 12/27/2022]
Abstract
PARK14 patients with homozygous (D331Y) PLA2G6 mutation display motor deficits of pure early-onset Parkinson's disease (PD). The aim of this study is to investigate the pathogenic mechanism of mutant (D331Y) PLA2G6-induced PD. We generated knockin (KI) mouse model of PARK14 harboring homozygous (D331Y) PLA2G6 mutation. Then, we investigated neuropathological and neurological phenotypes of PLA2G6D331Y/D331Y KI mice and molecular pathogenic mechanisms of (D331Y) PLA2G6-induced degeneration of substantia nigra (SN) dopaminergic neurons. Six-or nine-month-old PLA2G6D331Y/D331Y KI mice displayed early-onset cell death of SNpc dopaminergic neurons. Lewy body pathology was found in the SN of PLA2G6D331Y/D331Y mice. Six-or nine-month-old PLA2G6D331Y/D331Y KI mice exhibited early-onset parkinsonism phenotypes. Disrupted cristae of mitochondria were found in SNpc dopaminergic neurons of PLA2G6D331Y/D331Y mice. PLA2G6D331Y/D331Y mice displayed mitochondrial dysfunction and upregulated ROS production, which may lead to activation of apoptotic cascade. Upregulated protein levels of Grp78, IRE1, PERK, and CHOP, which are involved in activation of ER stress, were found in the SN of PLA2G6D331Y/D331Y mice. Protein expression of mitophagic proteins, including parkin and BNIP3, was downregulated in the SN of PLA2G6D331Y/D331Y mice, suggesting that (D331Y) PLA2G6 mutation causes mitophagy dysfunction. In the SN of PLA2G6D331Y/D331Y mice, mRNA levels of eight genes that are involved in neuroprotection/neurogenesis were decreased, while mRNA levels of two genes that promote apoptotic death were increased. Our results suggest that PARK14 (D331Y) PLA2G6 mutation causes degeneration of SNpc dopaminergic neurons by causing mitochondrial dysfunction, elevated ER stress, mitophagy impairment, and transcriptional abnormality.
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Affiliation(s)
- Ching-Chi Chiu
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Linkou, Taoyuan, Taiwan.,Department of Nursing, Chang Gung University of Science and Technology, Taoyuan, Taiwan.,Healthy Aging Research Center, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Chin-Song Lu
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Linkou, Taoyuan, Taiwan.,Healthy Aging Research Center, Chang Gung University College of Medicine, Taoyuan, Taiwan.,Division of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yi-Hsin Weng
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Linkou, Taoyuan, Taiwan.,Healthy Aging Research Center, Chang Gung University College of Medicine, Taoyuan, Taiwan.,Division of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ying-Ling Chen
- Department of Nursing, Chang Gung University of Science and Technology, Taoyuan, Taiwan
| | - Ying-Zu Huang
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Linkou, Taoyuan, Taiwan.,Healthy Aging Research Center, Chang Gung University College of Medicine, Taoyuan, Taiwan.,Division of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
| | - Rou-Shayn Chen
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Linkou, Taoyuan, Taiwan.,Healthy Aging Research Center, Chang Gung University College of Medicine, Taoyuan, Taiwan.,Division of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yi-Chuan Cheng
- Graduate Institute of Biomedical Sciences, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Yin-Cheng Huang
- College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Neurosurgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Yu-Chuan Liu
- Division of Sports Medicine, Taiwan Landseed Hospital, Taoyuan, Taiwan
| | - Szu-Chia Lai
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Linkou, Taoyuan, Taiwan.,Healthy Aging Research Center, Chang Gung University College of Medicine, Taoyuan, Taiwan.,Division of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Kun-Jun Lin
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Linkou, Taoyuan, Taiwan.,Molecular Imaging Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Yan-Wei Lin
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Linkou, Taoyuan, Taiwan.,Division of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Yu-Jie Chen
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Linkou, Taoyuan, Taiwan
| | - Chao-Lang Chen
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Linkou, Taoyuan, Taiwan
| | - Tu-Hsueh Yeh
- Department of Neurology, Taipei Medical University Hospital, No. 252, Wuxing St, Xinyi District, Taipei City, 110, Taiwan. .,School of Medicine, Taipei Medical University, Taipei, Taiwan.
| | - Hung-Li Wang
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Linkou, Taoyuan, Taiwan. .,Healthy Aging Research Center, Chang Gung University College of Medicine, Taoyuan, Taiwan. .,Division of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan. .,Department of Physiology and Pharmacology, Chang Gung University College of Medicine, No. 259, Wen-Hwa 1st Road, Kweishan, Taoyuan, 333, Taiwan.
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103
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Petan T, Jarc E, Jusović M. Lipid Droplets in Cancer: Guardians of Fat in a Stressful World. Molecules 2018; 23:molecules23081941. [PMID: 30081476 PMCID: PMC6222695 DOI: 10.3390/molecules23081941] [Citation(s) in RCA: 217] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 07/31/2018] [Accepted: 08/01/2018] [Indexed: 12/12/2022] Open
Abstract
Cancer cells possess remarkable abilities to adapt to adverse environmental conditions. Their survival during severe nutrient and oxidative stress depends on their capacity to acquire extracellular lipids and the plasticity of their mechanisms for intracellular lipid synthesis, mobilisation, and recycling. Lipid droplets, cytosolic fat storage organelles present in most cells from yeast to men, are emerging as major regulators of lipid metabolism, trafficking, and signalling in various cells and tissues exposed to stress. Their biogenesis is induced by nutrient and oxidative stress and they accumulate in various cancers. Lipid droplets act as switches that coordinate lipid trafficking and consumption for different purposes in the cell, such as energy production, protection against oxidative stress or membrane biogenesis during rapid cell growth. They sequester toxic lipids, such as fatty acids, cholesterol and ceramides, thereby preventing lipotoxic cell damage and engage in a complex relationship with autophagy. Here, we focus on the emerging mechanisms of stress-induced lipid droplet biogenesis; their roles during nutrient, lipotoxic, and oxidative stress; and the relationship between lipid droplets and autophagy. The recently discovered principles of lipid droplet biology can improve our understanding of the mechanisms that govern cancer cell adaptability and resilience to stress.
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Affiliation(s)
- Toni Petan
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia.
| | - Eva Jarc
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia.
- Jožef Stefan International Postgraduate School, Ljubljana SI-1000, Slovenia.
| | - Maida Jusović
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia.
- Jožef Stefan International Postgraduate School, Ljubljana SI-1000, Slovenia.
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104
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Lysosomal phospholipase A2. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:932-940. [PMID: 30077006 DOI: 10.1016/j.bbalip.2018.07.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 07/23/2018] [Accepted: 07/24/2018] [Indexed: 12/31/2022]
Abstract
Lysosomal phospholipase A2 (PLA2G15) is a ubiquitous enzyme uniquely characterized by a subcellular localization to the lysosome and late endosome. PLA2G15 has an acidic pH optimum, is calcium independent, and acts as a transacylase in the presence of N-acetyl-sphingosine as an acceptor. Recent studies aided by the delineation of the crystal structure of PLA2G15 have clarified further the catalytic mechanism, sn-1 versus sn-2 specificity, and the basis whereby cationic amphiphilic drugs inhibit its activity. PLA2G15 has recently been shown to hydrolyze short chain oxidized phospholipids which access the catalytic site directly based on their aqueous solubility. Studies on the PLA2G15 null mouse suggest a role for the enzyme in the catabolism of pulmonary surfactant. PLA2G15 may also have a role in host defense and in the processing of lipid antigens for presentation by CD1 proteins. This article is part of a Special Issue entitled Novel functions of phospholipase A2 Guest Editors: Makoto Murakami and Gerard Lambeau.
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105
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Selectivity of phospholipid hydrolysis by phospholipase A 2 enzymes in activated cells leading to polyunsaturated fatty acid mobilization. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:772-783. [PMID: 30010011 DOI: 10.1016/j.bbalip.2018.07.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/08/2018] [Accepted: 07/10/2018] [Indexed: 12/14/2022]
Abstract
Phospholipase A2s are enzymes that hydrolyze the fatty acid at the sn-2 position of the glycerol backbone of membrane glycerophospholipids. Given the asymmetric distribution of fatty acids within phospholipids, where saturated fatty acids tend to be present at the sn-1 position, and polyunsaturated fatty acids such as those of the omega-3 and omega-6 series overwhelmingly localize in the sn-2 position, the phospholipase A2 reaction is of utmost importance as a regulatory checkpoint for the mobilization of these fatty acids and the subsequent synthesis of proinflammatory omega-6-derived eicosanoids on one hand, and omega-3-derived specialized pro-resolving mediators on the other. The great variety of phospholipase A2s, their differential substrate selectivity under a variety of pathophysiological conditions, as well as the different compartmentalization of each enzyme and accessibility to substrate, render this class of enzymes also key to membrane phospholipid remodeling reactions, and the generation of specific lipid mediators not related with canonical metabolites of omega-6 or omega-3 fatty acids. This review highlights novel findings regarding the selective hydrolysis of phospholipids by phospholipase A2s and the influence this may have on the ability of these enzymes to generate distinct lipid mediators with essential functions in biological processes. This brings a new understanding of the cellular roles of these enzymes depending upon activation conditions.
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106
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Yang B, Li R, Michael Greenlief C, Fritsche KL, Gu Z, Cui J, Lee JC, Beversdorf DQ, Sun GY. Unveiling anti-oxidative and anti-inflammatory effects of docosahexaenoic acid and its lipid peroxidation product on lipopolysaccharide-stimulated BV-2 microglial cells. J Neuroinflammation 2018; 15:202. [PMID: 29986724 PMCID: PMC6038194 DOI: 10.1186/s12974-018-1232-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 06/20/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Phospholipids in the central nervous system are enriched in n-3 and n-6 polyunsaturated fatty acids (PUFA), especially docosahexaenoic acid (DHA) and arachidonic acid (ARA). These PUFA can undergo enzymatic reactions to produce lipid mediators, as well as reaction with oxygen free radicals to produce 4-hydroxyhexenal (4-HHE) from DHA and 4-hydroxynonenal (4-HNE) from ARA. Recent studies demonstrated pleiotropic properties of these peroxidation products through interaction with oxidative and anti-oxidant response pathways. In this study, BV-2 microglial cells were used to investigate ability for DHA, 4-HHE, and 4-HNE to stimulate the anti-oxidant stress responses involving the nuclear factor erythroid-2-related factor 2 (Nrf2) pathway and synthesis of heme oxygenase (HO-1), as well as to mitigate lipopolysaccharide (LPS)-induced nitric oxide (NO), reactive oxygen species (ROS), and cytosolic phospholipase A2 (cPLA2). In addition, LC-MS/MS analysis was carried out to examine effects of exogenous DHA and LPS stimulation on endogenous 4-HHE and 4-HNE levels in BV-2 microglial cells. METHODS Effects of DHA, 4-HHE, and 4-HNE on LPS-induced NO production was determined using the Griess reagent. LPS-induced ROS production was measured using CM-H2DCFDA. Western blots were used to analyze expression of p-cPLA2, Nrf2, and HO-1. Cell viability and cytotoxicity were measured using the WST-1 assay, and cell protein concentrations were measured using the BCA protein assay kit. An ultra-high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis was used to determine levels of free 4-HHE and 4-HNE in cells. RESULTS DHA (12.5-100 μM), 4-HHE (1.25-10 μM), and 4-HNE (1.25-10 μM) dose dependently suppressed LPS-induced production of NO, ROS, and as p-cPLA2 in BV-2 microglial cells. With the same concentrations, these compounds could enhance Nrf2 and HO-1 expression in these cells. Based on the estimated IC50 values, 4-HHE and 4-HNE were five- to tenfold more potent than DHA in inhibiting LPS-induced NO, ROS, and p-cPLA2. LC-MS/MS analysis indicated ability for DHA (10-50 μM) to increase levels of 4-HHE and attenuate levels of 4-HNE in BV-2 microglial cells. Stimulation of cells with LPS caused an increase in 4-HNE which could be abrogated by cPLA2 inhibitor. In contrast, bromoenol lactone (BEL), a specific inhibitor for the Ca2+-independent phospholipase A2 (iPLA2), could only partially suppress levels of 4-HHE induced by DHA or DHA + LPS. CONCLUSIONS This study demonstrated the ability of DHA and its lipid peroxidation products, namely, 4-HHE and 4-HNE at 1.25-10 μM, to enhance Nrf2/HO-1 and mitigate LPS-induced NO, ROS, and p-cPLA2 in BV-2 microglial cells. In addition, LC-MS/MS analysis of the levels of 4-HHE and 4-HNE in microglial cells demonstrates that increases in production of 4-HHE from DHA and 4-HNE from LPS are mediated by different mechanisms.
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Affiliation(s)
- Bo Yang
- Chemistry Department, University of Missouri, Columbia, MO, USA
| | - Runting Li
- Biochemistry Department, University of Missouri, 117 Schweitzer Hall, Columbia, MO, 65211, USA
| | | | - Kevin L Fritsche
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USA
| | - Zezong Gu
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA
| | - Jiankun Cui
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA
| | - James C Lee
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - David Q Beversdorf
- Departments of Radiology, Neurology and Psychological Sciences, University of Missouri, Columbia, MO, USA
| | - Grace Y Sun
- Biochemistry Department, University of Missouri, 117 Schweitzer Hall, Columbia, MO, 65211, USA. .,Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA.
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107
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Su H, Zhang H, Wei X, Pan D, Jing L, Zhao D, Zhao Y, Qi B. Comparative Proteomic Analysis of Rana chensinensis Oviduct. Molecules 2018; 23:1384. [PMID: 29890619 PMCID: PMC6099995 DOI: 10.3390/molecules23061384] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 05/31/2018] [Accepted: 06/05/2018] [Indexed: 12/31/2022] Open
Abstract
As one of most important traditional Chinese medicine resources, the oviduct of female Rana chensinensis (Chinese brown frog) was widely used in the treatment of asthenia after sickness or delivery, deficiency in vigor, palpitation, and insomnia. Unlike other vertebrates, the oviduct of Rana chensinensis oviduct significantly expands during prehibernation, in contrast to the breeding period. To explain this phenomenon at the molecular level, the protein expression profiles of Rana chensinensis oviduct during the breeding period and prehibernation were observed using isobaric tags for relative and absolute quantitation (iTRAQ) technique. Then, all identified proteins were used to obtain gene ontology (GO) annotation. Ultimately, KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis was performed to predict the pathway on differentially expressed proteins (DEPs). A total of 4479 proteins were identified, and 312 of them presented different expression profiling between prehibernation and breeding period. Compared with prehibernation group, 86 proteins were upregulated, and 226 proteins were downregulated in breeding period. After KEGG enrichment analysis, 163 DEPs were involved in 6 pathways, which were lysosome, RNA transport, glycosaminoglycan degradation, extracellular matrix (ECM)⁻receptor interaction, metabolic pathways and focal adhesion. This is the first report on the protein profiling of Rana chensinensis oviduct during the breeding period and prehibernation. Results show that this distinctive physiological phenomenon of Rana chensinensis oviduct was mainly involved in ECM⁻receptor interaction, metabolic pathways, and focal adhesion.
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Affiliation(s)
- Hang Su
- Practice Innovations Center, Changchun University of Chinese Medicine, Changchun 130117, China.
| | - He Zhang
- School of Clinical Medicine, Changchun University of Chinese Medicine, Changchun 130117, China.
| | - Xinghua Wei
- Jilin Science Service Center, Changchun 130021, China.
| | - Daian Pan
- School of Clinical Medicine, Changchun University of Chinese Medicine, Changchun 130117, China.
| | - Li Jing
- Practice Innovations Center, Changchun University of Chinese Medicine, Changchun 130117, China.
| | - Daqing Zhao
- Jilin Ginseng Academy, Changchun University of Chinese Medicine, Changchun 130117, China.
| | - Yu Zhao
- Jilin Ginseng Academy, Changchun University of Chinese Medicine, Changchun 130117, China.
| | - Bin Qi
- College of Pharmacy, Changchun University of Chinese Medicine, Changchun 130117, China.
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108
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O'Donnell VB, Rossjohn J, Wakelam MJ. Phospholipid signaling in innate immune cells. J Clin Invest 2018; 128:2670-2679. [PMID: 29683435 DOI: 10.1172/jci97944] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Phospholipids comprise a large body of lipids that define cells and organelles by forming membrane structures. Importantly, their complex metabolism represents a highly controlled cellular signaling network that is essential for mounting an effective innate immune response. Phospholipids in innate cells are subject to dynamic regulation by enzymes, whose activities are highly responsive to activation status. Along with their metabolic products, they regulate multiple aspects of innate immune cell biology, including shape change, aggregation, blood clotting, and degranulation. Phospholipid hydrolysis provides substrates for cell-cell communication, enables regulation of hemostasis, immunity, thrombosis, and vascular inflammation, and is centrally important in cardiovascular disease and associated comorbidities. Phospholipids themselves are also recognized by innate-like T cells, which are considered essential for recognition of infection or cancer, as well as self-antigens. This Review describes the major phospholipid metabolic pathways present in innate immune cells and summarizes the formation and metabolism of phospholipids as well as their emerging roles in cell biology and disease.
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Affiliation(s)
- Valerie B O'Donnell
- Systems Immunity Research Institute and Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Jamie Rossjohn
- Systems Immunity Research Institute and Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom.,Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, and.,ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria, Australia
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109
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Jabůrek M, Ježek J, Ježek P. Cytoprotective activity of mitochondrial uncoupling protein-2 in lung and spleen. FEBS Open Bio 2018; 8:692-701. [PMID: 29632821 PMCID: PMC5881546 DOI: 10.1002/2211-5463.12410] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 02/06/2018] [Accepted: 02/12/2018] [Indexed: 01/14/2023] Open
Abstract
Mitochondrial uncoupling protein‐2 (UCP2) mediates free fatty acid (FA)‐dependent H+ translocation across the inner mitochondrial membrane (IMM), which leads to acceleration of respiration and suppression of mitochondrial superoxide formation. Redox‐activated mitochondrial phospholipase A2 (mt‐iPLA2γ) cleaves FAs from the IMM and has been shown to acts in synergy with UCP2. Here, we tested the mechanism of mt‐iPLA2γ‐dependent UCP2‐mediated antioxidant protection using lipopolysaccharide (LPS)‐induced pro‐inflammatory and pro‐oxidative responses and their acute influence on the overall oxidative stress reflected by protein carbonylation in murine lung and spleen mitochondria and tissue homogenates. We provided challenges either by blocking the mt‐iPLA2γ function by the selective inhibitor R‐bromoenol lactone (R‐BEL) or by removing UCP2 by genetic ablation. We found that the basal levels of protein carbonyls in lung and spleen tissues and isolated mitochondria were higher in UCP2‐knockout mice relative to the wild‐type (wt) controls. The administration of R‐BEL increased protein carbonyl levels in wt but not in UCP2‐knockout (UCP2‐KO) mice. LPS further increased the protein carbonyl levels in UCP2‐KO mice, which correlated with protein carbonyl levels determined in wt mice treated with R‐BEL. These results are consistent with the UCP2/mt‐iPLA2γ antioxidant mechanisms in these tissues and support the existence of UCP2‐synergic mt‐iPLA2γ‐dependent cytoprotective mechanism in vivo.
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Affiliation(s)
- Martin Jabůrek
- Department of Mitochondrial Physiology Institute of Physiology Academy of Sciences Prague Czech Republic
| | - Jan Ježek
- Department of Mitochondrial Physiology Institute of Physiology Academy of Sciences Prague Czech Republic
| | - Petr Ježek
- Department of Mitochondrial Physiology Institute of Physiology Academy of Sciences Prague Czech Republic
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110
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Faccio AT, Ruperez FJ, Singh NS, Angulo S, Tavares MFM, Bernier M, Barbas C, Wainer IW. Stereochemical and structural effects of (2R,6R)-hydroxynorketamine on the mitochondrial metabolome in PC-12 cells. Biochim Biophys Acta Gen Subj 2018. [PMID: 29526507 DOI: 10.1016/j.bbagen.2018.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Impairment in mitochondrial biogenesis and function plays a key role in depression and anxiety, both of which being associated with changes in fatty acid and phospholipid metabolism. The antidepressant effects of (R,S)-ketamine have been linked to its conversion into (2S,6S;2R,6R)-hydroxynorketamine (HNK); however, the connection between structure and stereochemistry of ketamine and HNK in the mitochondrial homeostatic response has not yet been fully elucidated at a metabolic level. METHODS We used a multi-platform, non-targeted metabolomics approach to study the change in mitochondrial metabolome of PC-12 cells treated with ketamine and HNK enantiomers. The identified metabolites were grouped into pathways in order to assess global responses. RESULTS Treatment with (2R,6R)-HNK elicited the significant change in 49 metabolites and associated pathways implicated in fundamental mitochondrial functions such as TCA cycle, branched-chain amino acid biosynthetic pathway, glycoxylate metabolic pathway, and fatty acid β-oxidation. The affected metabolites included glycerate, citrate, leucine, N,N-dimethylglycine, 3-hexenedioic acid, and carnitine and attenuated signals associated with 9 fatty acids and elaidic acid. Important metabolites involved in the purine and pyrimidine pathways were also affected by (2R-6R)-HNK. This global metabolic profile was not as strongly impacted by treatment with (2S,6S)-HNK, (R)- and (S)-ketamine and in some instances opposite effects were observed. CONCLUSIONS The present data provide an overall view of the metabolic changes in mitochondrial function produced by (2R,6R)-HNK and related ketamine compounds and offer an insight into the source of the observed variance in antidepressant response elicited by the compounds.
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Affiliation(s)
- Andréa T Faccio
- CEMBIO (Centre for Metabolomics and Bioanalysis), Faculty of Pharmacy, Universidad San Pablo CEU, Campus Monteprincipe, Boadilla del Monte, 28668 Madrid, Spain; Institute of Chemistry, University of São Paulo (USP), 05513-970 São Paulo, SP, Brazil
| | - Francisco J Ruperez
- CEMBIO (Centre for Metabolomics and Bioanalysis), Faculty of Pharmacy, Universidad San Pablo CEU, Campus Monteprincipe, Boadilla del Monte, 28668 Madrid, Spain
| | - Nagendra S Singh
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Santiago Angulo
- CEMBIO (Centre for Metabolomics and Bioanalysis), Faculty of Pharmacy, Universidad San Pablo CEU, Campus Monteprincipe, Boadilla del Monte, 28668 Madrid, Spain
| | - Marina F M Tavares
- Institute of Chemistry, University of São Paulo (USP), 05513-970 São Paulo, SP, Brazil
| | - Michel Bernier
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Coral Barbas
- CEMBIO (Centre for Metabolomics and Bioanalysis), Faculty of Pharmacy, Universidad San Pablo CEU, Campus Monteprincipe, Boadilla del Monte, 28668 Madrid, Spain
| | - Irving W Wainer
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA; Mitchell Woods Pharmaceuticals, Shelton, CT 06484, USA.
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111
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Malley KR, Koroleva O, Miller I, Sanishvili R, Jenkins CM, Gross RW, Korolev S. The structure of iPLA 2β reveals dimeric active sites and suggests mechanisms of regulation and localization. Nat Commun 2018; 9:765. [PMID: 29472584 PMCID: PMC5823874 DOI: 10.1038/s41467-018-03193-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 01/26/2018] [Indexed: 11/17/2022] Open
Abstract
Calcium-independent phospholipase A2β (iPLA2β) regulates important physiological processes including inflammation, calcium homeostasis and apoptosis. It is genetically linked to neurodegenerative disorders including Parkinson’s disease. Despite its known enzymatic activity, the mechanisms underlying iPLA2β-induced pathologic phenotypes remain poorly understood. Here, we present a crystal structure of iPLA2β that significantly revises existing mechanistic models. The catalytic domains form a tight dimer. They are surrounded by ankyrin repeat domains that adopt an outwardly flared orientation, poised to interact with membrane proteins. The closely integrated active sites are positioned for cooperative activation and internal transacylation. The structure and additional solution studies suggest that both catalytic domains can be bound and allosterically inhibited by a single calmodulin. These features suggest mechanisms of iPLA2β cellular localization and activity regulation, providing a basis for inhibitor development. Furthermore, the structure provides a framework to investigate the role of neurodegenerative mutations and the function of iPLA2β in the brain. Calcium-independent phospholipase A2β (iPLA2β) is involved in many physiological and pathological processes but the underlying mechanisms are largely unknown. Here, the authors present the structure of dimeric iPLA2β, providing insights into the regulation of its activity and cellular localization.
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Affiliation(s)
- Konstantin R Malley
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Olga Koroleva
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Ian Miller
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Ruslan Sanishvili
- GM/CA@APS, Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Christopher M Jenkins
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8020, Saint Louis, MO, 63110, USA
| | - Richard W Gross
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8020, Saint Louis, MO, 63110, USA.,Department of Developmental Biology, Washington University School of Medicine, Saint Louis, MO, 63110, USA.,Department of Medicine, Center for Cardiovascular Research, Washington University School of Medicine, Saint Louis, MO, 63110, USA.,Department of Chemistry, Washington University, Saint Louis, MO, 63130, USA
| | - Sergey Korolev
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA.
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112
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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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113
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Tamura S, Wang Y, Veeneman B, Hovelson D, Bankhead A, Broses LJ, Lorenzatti Hiles G, Liebert M, Rubin JR, Day KC, Hussain M, Neamati N, Tomlins S, Palmbos PL, Grivas P, Day ML. Molecular Correlates of In Vitro Responses to Dacomitinib and Afatinib in Bladder Cancer. Bladder Cancer 2018; 4:77-90. [PMID: 29430509 PMCID: PMC5798519 DOI: 10.3233/blc-170144] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Background: The HER family of proteins (EGFR, HER2, HER3 and HER4) have long been thought to be therapeutic targets for bladder cancer, but previous clinical trials targeting these proteins have been disappointing. Second generation agents may be more effective. Objective: The aim of this study was to evaluate responses to two second-generation irreversible tyrosine kinase inhibitors, dacomitinib and afatinib, in bladder cancer cell lines. Methods: Cell lines were characterized by targeted next generation DNA sequencing, RNA sequencing, western blotting and flow cytometry. Cell survival responses to dacomitinib or afatinib were determined using (3-[4,5-dimethylthioazol-2-yl]-2,5-diphenyl tetrazolium bromide) (MTT) or [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) and phenazine methosylfate (PMS) cell survival assays. Results: Only two cell lines of 12 tested were sensitive to afatinib. Sensitivity to afatinib was significantly associated with mutation in either HER2 or HER3 (p < 0.05). The two cell lines sensitive to afatinib were also responsive to dacomitinib ralong with an additional 4 other cell lines out of 16 tested. No characteristic was associated with dacomitinib sensitivity. Molecular profiling demonstrated that only two genes were high in both afatinib and dacomitinib sensitive cells. Further rhigher expression of RAS pathway genes was noted for dacomitinib responsive cells. Conclusions: This study confirms that cell line screening can be useful in pre-clinical evaluation of targeted small molecule inhibitors and suggests that compounds with similar structure(s) and target(s) may have distinct sensitivity profiles. Further rcombinational targeting of additional molecularly relevant pathways may be important in enhancing responses to HER targeted agents in bladder cancer.
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Affiliation(s)
- Shuzo Tamura
- Department of Medicinal Chemistry, School of Pharmacy, University of Michigan, Ann Arbor, MI, USA.,Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Current address: Yokohama City University, Yokohama City, Japan
| | - Yin Wang
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Brendan Veeneman
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Department of Pathology, University of Michigan, Ann Arbor, MI, USA.,Current Address: Pfizer, Pearl River, NY, USA
| | - Daniel Hovelson
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Armand Bankhead
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - Luke J Broses
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Department of Urology, University of Michigan, Ann Arbor, MI, USA
| | - Guadalupe Lorenzatti Hiles
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Department of Urology, University of Michigan, Ann Arbor, MI, USA
| | - Monica Liebert
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Department of Urology, University of Michigan, Ann Arbor, MI, USA
| | - John R Rubin
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Department of Urology, University of Michigan, Ann Arbor, MI, USA
| | - Kathleen C Day
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Department of Urology, University of Michigan, Ann Arbor, MI, USA
| | - Maha Hussain
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA.,Department of Urology, University of Michigan, Ann Arbor, MI, USA.,Current Address: Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL, USA
| | - Nouri Neamati
- Department of Medicinal Chemistry, School of Pharmacy, University of Michigan, Ann Arbor, MI, USA.,Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | - Scott Tomlins
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Philip L Palmbos
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Petros Grivas
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA.,Current address: University of Washington, Seattle, WA, USA
| | - Mark L Day
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.,Department of Urology, University of Michigan, Ann Arbor, MI, USA
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Abstract
Phospholipases are lipolytic enzymes that hydrolyze phospholipid substrates at specific ester bonds. Phospholipases are widespread in nature and play very diverse roles from aggression in snake venom to signal transduction, lipid mediator production, and metabolite digestion in humans. Phospholipases vary considerably in structure, function, regulation, and mode of action. Tremendous advances in understanding the structure and function of phospholipases have occurred in the last decades. This introductory chapter is aimed at providing a general framework of the current understanding of phospholipases and a discussion of their mechanisms of action and emerging biological functions.
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115
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Gao K, Zhao H, Gao J, Wen B, Jia C, Wang Z, Zhang F, Wang J, Xie H, Wang J, Wang W, Chen J. Mechanism of Chinese Medicine Herbs Effects on Chronic Heart Failure Based on Metabolic Profiling. Front Pharmacol 2017; 8:864. [PMID: 29213243 PMCID: PMC5702651 DOI: 10.3389/fphar.2017.00864] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/09/2017] [Indexed: 12/13/2022] Open
Abstract
Chronic heart failure (CHF) is a major public health problem in huge population worldwide. The detailed understanding of CHF mechanism is still limited. Zheng (syndrome) is the criterion of diagnosis and therapeutic in Traditional Chinese Medicine (TCM). Syndrome prediction may be a better approach for understanding of CHF mechanism basis and its treatment. The authors studied disturbed metabolic biomarkers to construct a predicting mode to assess the diagnostic value of different syndrome of CHF and explore the Chinese herbal medicine (CHM) efficacy on CHF patients. A cohort of 110 patients from 11 independent centers was studied and all patients were divided into 3 groups according to TCM syndrome differentiation: group of Qi deficiency syndrome, group of Qi deficiency and Blood stasis syndrome, and group of Qi deficiency and Blood stasis and Water retention syndrome. Plasma metabolomic profiles were determined by UPLC-TOF/MS and analyzed by multivariate statistics. About 6 representative metabolites were highly possible to be associated with CHF, 4, 7, and 5 metabolites with Qi deficiency syndrome, Qi deficiency and Blood stasis syndrome, and Qi deficiency and Blood stasis and Water retention syndrome (VIP > 1, p < 0.05). The diagnostic model was further constructed based on the metabolites to diagnose other CHF patients with satisfying sensitivity and specificity (sensitivity and specificity are 97.1 and 80.6% for CHF group vs. NH group; 97.1 and 80.0% for QD group vs. NH group; 97.1 and 79.5% for QB group vs. NH group; 97.1 and 88.9% for QBW group vs. NH group), validating the robustness of plasma metabolic profiling to diagnostic strategy. By comparison of the metabolic profiles, 9 biomarkers, 2-arachidonoylglycerophosphocholine, LysoPE 16:0, PS 21:0, LysoPE 20:4, LysoPE 18:0, linoleic acid, LysoPE 18:2, 4-hydroxybenzenesulfonic acid, and LysoPE 22:6, may be especially for the effect of CHM granules. A predicting model was attempted to construct and predict patient based on the related symptoms of CHF and the potential biomarkers regulated by CHM were explored. This trial was registered with NCT01939236 (https://clinicaltrials.gov/).
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Affiliation(s)
- Kuo Gao
- School of Preclinical Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Huihui Zhao
- School of Preclinical Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Jian Gao
- School of Preclinical Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Binyu Wen
- Beijing University of Chinese Medicine, Dongfang Hospital, Beijing, China
| | - Caixia Jia
- School of Preclinical Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Zhiyong Wang
- FengNing Chinese Medicine Hospital, FengNing, China
| | - Feilong Zhang
- School of Preclinical Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Jinping Wang
- School of Preclinical Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Hua Xie
- School of Preclinical Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Juan Wang
- School of Preclinical Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Wei Wang
- School of Preclinical Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Jianxin Chen
- School of Preclinical Medicine, Beijing University of Chinese Medicine, Beijing, China
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116
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PARK14 PLA2G6 mutants are defective in preventing rotenone-induced mitochondrial dysfunction, ROS generation and activation of mitochondrial apoptotic pathway. Oncotarget 2017; 8:79046-79060. [PMID: 29108286 PMCID: PMC5668019 DOI: 10.18632/oncotarget.20893] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 08/17/2017] [Indexed: 11/25/2022] Open
Abstract
Mutations in the gene encoding Ca2+-independent phospholipase A2 group 6 (PLA2G6) cause the recessive familial type 14 of Parkinson’s disease (PARK14). Mitochondrial dysfunction is involved in the pathogenesis of Parkinson’s disease (PD). PLA2G6 is believed to be required for maintaining mitochondrial function. In the present study, rotenone-induced cellular model of PD was used to investigate possible molecular pathogenic mechanism of PARK14 mutant PLA2G6-induced PD. Overexpression of wild-type (WT) PLA2G6 ameliorated rotenone-induced apoptotic death of SH-SY5Y dopaminergic cells. PARK14 mutant (D331Y), (G517C), (T572I), (R632W), (N659S) or (R741Q) PLA2G6 failed to prevent rotenone-induced activation of mitochondrial apoptotic pathway and exert a neuroprotective effect. WT PLA2G6, but not PARK14 mutant PLA2G6, prevented rotenone-induced mitophagy impairment. In contrast to WT PLA2G6, PARK14 mutant PLA2G6 was ineffective in attenuating rotenone-induced decrease in mitochondrial membrane potential and increase in the level of mitochondrial superoxide. WT PLA2G6, but not PARK14 PLA2G6 mutants, restored enzyme activity of mitochondrial complex I and cellular ATP content in rotenone-treated SH-SY5Y dopaminergic cells. In contrast to WT PLA2G6, PARK14 mutant PLA2G6 failed to prevent rotenone-induced mitochondrial lipid peroxidation and cytochrome c release. These results suggest that PARK14 PLA2G6 mutants lose their ability to maintain mitochondrial function and are defective inpreventing mitochondrial dysfunction, ROS production and activation of mitochondrial apoptotic pathway in rotenone-induced cellular model of PD.
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Chemokines (CCL3, CCL4, and CCL5) Inhibit ATP-Induced Release of IL-1 β by Monocytic Cells. Mediators Inflamm 2017; 2017:1434872. [PMID: 28757683 PMCID: PMC5516742 DOI: 10.1155/2017/1434872] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 03/31/2017] [Accepted: 04/20/2017] [Indexed: 01/07/2023] Open
Abstract
Chemokines and ATP are among the mediators of inflammatory sites that can enter the circulation via damaged blood vessels. The main function of chemokines is leukocyte mobilization, and ATP typically triggers inflammasome assembly. IL-1β, a potent inflammasome-dependent cytokine of innate immunity, is essential for pathogen defense. However, excessive IL-1β may cause life-threatening systemic inflammation. Here, we hypothesize that chemokines control ATP-dependent secretion of monocytic IL-1β. Lipopolysaccharide-primed human monocytic U937 cells were stimulated with the P2X7 agonist BzATP for 30 min to induce IL-1β release. CCL3, CCL4, and CCL5 dose dependently inhibited BzATP-stimulated release of IL-1β, whereas CXCL16 was ineffective. The effect of CCL3 was confirmed for primary mononuclear leukocytes. It was blunted after silencing CCR1 or calcium-independent phospholipase A2 (iPLA2) by siRNA and was sensitive to antagonists of nicotinic acetylcholine receptors containing subunits α7 and α9. U937 cells secreted small factors in response to CCL3 that mediated the inhibition of IL-1β release. We suggest that CCL chemokines inhibit ATP-induced release of IL-1β from U937 cells by a triple-membrane-passing mechanism involving CCR, iPLA2, release of small mediators, and nicotinic acetylcholine receptor subunits α7 and α9. We speculate that whenever chemokines and ATP enter the circulation concomitantly, systemic release of IL-1β is minimized.
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118
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Macrophages and Phospholipases at the Intersection between Inflammation and the Pathogenesis of HIV-1 Infection. Int J Mol Sci 2017; 18:ijms18071390. [PMID: 28661459 PMCID: PMC5535883 DOI: 10.3390/ijms18071390] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 06/22/2017] [Accepted: 06/26/2017] [Indexed: 12/12/2022] Open
Abstract
Persistent low grade immune activation and chronic inflammation are nowadays considered main driving forces of the progressive immunologic failure in effective antiretroviral therapy treated HIV-1 infected individuals. Among the factors contributing to this phenomenon, microbial translocation has emerged as a key driver of persistent immune activation. Indeed, the rapid depletion of gastrointestinal CD4+ T lymphocytes occurring during the early phases of infection leads to a deterioration of the gut epithelium followed by the translocation of microbial products into the systemic circulation and the subsequent activation of innate immunity. In this context, monocytes/macrophages are increasingly recognized as an important source of inflammation, linked to HIV-1 disease progression and to non-AIDS complications, such as cardiovascular disease and neurocognitive decline, which are currently main challenges in treated patients. Lipid signaling plays a central role in modulating monocyte/macrophage activation, immune functions and inflammatory responses. Phospholipase-mediated phospholipid hydrolysis leads to the production of lipid mediators or second messengers that affect signal transduction, thus regulating a variety of physiologic and pathophysiologic processes. In this review, we discuss the contribution of phospholipases to monocyte/macrophage activation in the context of HIV-1 infection, focusing on their involvement in virus-associated chronic inflammation and co-morbidities.
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119
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RIBEYE(B)-domain binds to lipid components of synaptic vesicles in an NAD(H)-dependent, redox-sensitive manner. Biochem J 2017; 474:1205-1220. [PMID: 28202712 DOI: 10.1042/bcj20160886] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 02/14/2017] [Accepted: 02/14/2017] [Indexed: 12/26/2022]
Abstract
Synaptic ribbons are needed for fast and continuous exocytosis in ribbon synapses. RIBEYE is a main protein component of synaptic ribbons and is necessary to build the synaptic ribbon. RIBEYE consists of a unique A-domain and a carboxyterminal B-domain, which binds NAD(H). Within the presynaptic terminal, the synaptic ribbons are in physical contact with large numbers of synaptic vesicle (SV)s. How this physical contact between ribbons and synaptic vesicles is established at a molecular level is not well understood. In the present study, we demonstrate that the RIBEYE(B)-domain can directly interact with lipid components of SVs using two different sedimentation assays with liposomes of defined chemical composition. Similar binding results were obtained with a SV-containing membrane fraction. The binding of liposomes to RIBEYE(B) depends upon the presence of a small amount of lysophospholipids present in the liposomes. Interestingly, binding of liposomes to RIBEYE(B) depends on NAD(H) in a redox-sensitive manner. The binding is enhanced by NADH, the reduced form, and is inhibited by NAD+, the oxidized form. Lipid-mediated attachment of vesicles is probably part of a multi-step process that also involves additional, protein-dependent processes.
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120
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The Molecular Basis of Toxins' Interactions with Intracellular Signaling via Discrete Portals. Toxins (Basel) 2017; 9:toxins9030107. [PMID: 28300784 PMCID: PMC5371862 DOI: 10.3390/toxins9030107] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/02/2017] [Accepted: 03/04/2017] [Indexed: 12/20/2022] Open
Abstract
An understanding of the molecular mechanisms by which microbial, plant or animal-secreted toxins exert their action provides the most important element for assessment of human health risks and opens new insights into therapies addressing a plethora of pathologies, ranging from neurological disorders to cancer, using toxinomimetic agents. Recently, molecular and cellular biology dissecting tools have provided a wealth of information on the action of these diverse toxins, yet, an integrated framework to explain their selective toxicity is still lacking. In this review, specific examples of different toxins are emphasized to illustrate the fundamental mechanisms of toxicity at different biochemical, molecular and cellular- levels with particular consideration for the nervous system. The target of primary action has been highlighted and operationally classified into 13 sub-categories. Selected examples of toxins were assigned to each target category, denominated as portal, and the modulation of the different portal’s signaling was featured. The first portal encompasses the plasma membrane lipid domains, which give rise to pores when challenged for example with pardaxin, a fish toxin, or is subject to degradation when enzymes of lipid metabolism such as phospholipases A2 (PLA2) or phospholipase C (PLC) act upon it. Several major portals consist of ion channels, pumps, transporters and ligand gated ionotropic receptors which many toxins act on, disturbing the intracellular ion homeostasis. Another group of portals consists of G-protein-coupled and tyrosine kinase receptors that, upon interaction with discrete toxins, alter second messengers towards pathological levels. Lastly, subcellular organelles such as mitochondria, nucleus, protein- and RNA-synthesis machineries, cytoskeletal networks and exocytic vesicles are also portals targeted and deregulated by other diverse group of toxins. A fundamental concept can be drawn from these seemingly different toxins with respect to the site of action and the secondary messengers and signaling cascades they trigger in the host. While the interaction with the initial portal is largely determined by the chemical nature of the toxin, once inside the cell, several ubiquitous second messengers and protein kinases/ phosphatases pathways are impaired, to attain toxicity. Therefore, toxins represent one of the most promising natural molecules for developing novel therapeutics that selectively target the major cellular portals involved in human physiology and diseases.
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121
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Lambie SC, Kretschmer M, Croll D, Haslam TM, Kunst L, Klose J, Kronstad JW. The putative phospholipase Lip2 counteracts oxidative damage and influences the virulence of Ustilago maydis. MOLECULAR PLANT PATHOLOGY 2017; 18:210-221. [PMID: 26950180 PMCID: PMC6638309 DOI: 10.1111/mpp.12391] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/29/2016] [Accepted: 03/02/2016] [Indexed: 06/05/2023]
Abstract
Ustilago maydis is an obligate biotrophic fungal pathogen which causes common smut disease of corn. To proliferate in host tissue, U. maydis must gain access to nutrients and overcome plant defence responses, such as the production of reactive oxygen species. The elucidation of the mechanisms by which U. maydis meets these challenges is critical for the development of strategies to combat smut disease. In this study, we focused on the contributions of phospholipases (PLs) to the pathogenesis of corn smut disease. We identified 11 genes encoding putative PLs and characterized the transcript levels for these genes in the fungus grown in culture and during infection of corn tissue. To assess the contributions of specific PLs, we focused on two genes, lip1 and lip2, which encode putative phospholipase A2 (PLA2 ) enzymes with similarity to platelet-activating factor acetylhydrolases. PLA2 enzymes are known to counteract oxidative damage to lipids in other organisms. Consistent with a role in the mitigation of oxidative damage, lip2 mutants were sensitive to oxidative stress provoked by hydrogen peroxide and by increased production of reactive oxygen species caused by inhibitors of mitochondrial functions. Importantly, mutants defective in lip2, but not lip1, were attenuated for virulence in corn seedlings. Finally, a comparative analysis of fatty acid and cardiolipin profiles in the wild-type strain and a lip2 mutant revealed differences consistent with a protective role for Lip2 in maintaining lipid homeostasis and mitochondrial health during proliferation in the hostile host environment.
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Affiliation(s)
- Scott C. Lambie
- Department of Microbiology and ImmunologyUniversity of British ColumbiaVancouver V6T 1Z3BCCanada
- The Michael Smith Laboratories, University of British ColumbiaVancouver V6T 1Z4BCCanada
| | - Matthias Kretschmer
- The Michael Smith Laboratories, University of British ColumbiaVancouver V6T 1Z4BCCanada
| | - Daniel Croll
- The Michael Smith Laboratories, University of British ColumbiaVancouver V6T 1Z4BCCanada
- Present address:
Institute of Integrative Biology, ETH Zürich8092 ZürichSwitzerland
| | - Tegan M. Haslam
- Department of BotanyUniversity of British ColumbiaVancouver V6T 1Z4BCCanada
| | - Ljerka Kunst
- Department of BotanyUniversity of British ColumbiaVancouver V6T 1Z4BCCanada
| | - Jana Klose
- Department of Microbiology and ImmunologyUniversity of British ColumbiaVancouver V6T 1Z3BCCanada
- The Michael Smith Laboratories, University of British ColumbiaVancouver V6T 1Z4BCCanada
| | - James W. Kronstad
- Department of Microbiology and ImmunologyUniversity of British ColumbiaVancouver V6T 1Z3BCCanada
- The Michael Smith Laboratories, University of British ColumbiaVancouver V6T 1Z4BCCanada
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122
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Chen TL, Yang HC, Hung CY, Ou MH, Pan YY, Cheng ML, Stern A, Lo SJ, Chiu DTY. Impaired embryonic development in glucose-6-phosphate dehydrogenase-deficient Caenorhabditis elegans due to abnormal redox homeostasis induced activation of calcium-independent phospholipase and alteration of glycerophospholipid metabolism. Cell Death Dis 2017; 8:e2545. [PMID: 28079896 PMCID: PMC5386372 DOI: 10.1038/cddis.2016.463] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/05/2016] [Accepted: 12/06/2016] [Indexed: 01/20/2023]
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a commonly pervasive inherited disease in many parts of the world. The complete lack of G6PD activity in a mouse model causes embryonic lethality. The G6PD-deficient Caenorhabditis elegans model also shows embryonic death as indicated by a severe hatching defect. Although increased oxidative stress has been implicated in both cases as the underlying cause, the exact mechanism has not been clearly delineated. In this study with C. elegans, membrane-associated defects, including enhanced permeability, defective polarity and cytokinesis, were found in G6PD-deficient embryos. The membrane-associated abnormalities were accompanied by impaired eggshell structure as evidenced by a transmission electron microscopic study. Such loss of membrane structural integrity was associated with abnormal lipid composition as lipidomic analysis revealed that lysoglycerophospholipids were significantly increased in G6PD-deficient embryos. Abnormal glycerophospholipid metabolism leading to defective embryonic development could be attributed to the increased activity of calcium-independent phospholipase A2 (iPLA) in G6PD-deficient embryos. This notion is further supported by the fact that the suppression of multiple iPLAs by genetic manipulation partially rescued the embryonic defects in G6PD-deficient embryos. In addition, G6PD deficiency induced disruption of redox balance as manifested by diminished NADPH and elevated lipid peroxidation in embryos. Taken together, disrupted lipid metabolism due to abnormal redox homeostasis is a major factor contributing to abnormal embryonic development in G6PD-deficient C. elegans.
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Affiliation(s)
- Tzu-Ling Chen
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Medical Biotechnology and Laboratory Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Hung-Chi Yang
- Department of Medical Biotechnology and Laboratory Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan
| | - Cheng-Yu Hung
- Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan
| | - Meng-Hsin Ou
- Department of Medical Biotechnology and Laboratory Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yi-Yun Pan
- Department of Medical Biotechnology and Laboratory Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Mei-Ling Cheng
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan.,Metabolomics Core Laboratory, Chang Gung University, Taoyuan, Taiwan.,Clinical Phenome Center, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Graduate Institute of Medical Biotechnology and Laboratory Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Arnold Stern
- New York University School of Medicine, New York,NY, USA
| | - Szecheng J Lo
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Daniel Tsun-Yee Chiu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Medical Biotechnology and Laboratory Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan.,Graduate Institute of Medical Biotechnology and Laboratory Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Pediatric Hematology/Oncology, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
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Smyrniotou A, Kokotou MG, Mouchlis VD, Barbayianni E, Kokotos G, Dennis EA, Constantinou-Kokotou V. 2-Oxoamides based on dipeptides as selective calcium-independent phospholipase A 2 inhibitors. Bioorg Med Chem 2016; 25:926-940. [PMID: 28034646 DOI: 10.1016/j.bmc.2016.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 12/04/2016] [Accepted: 12/05/2016] [Indexed: 11/18/2022]
Abstract
Calcium-independent phospholipase A2 (GVIA iPLA2) has recently attracted interest as a medicinal target. The number of known GVIA iPLA2 inhibitors is limited to a handful of synthetic compounds (bromoenol lactone and polyfluoroketones). To expand the chemical diversity, a variety of 2-oxoamides based on dipeptides and ether dipeptides were synthesized and studied for their in vitro inhibitory activity on human GVIA iPLA2 and their selectivity over the other major intracellular GIVA cPLA2 and the secreted GV sPLA2. Structure-activity relationship studies revealed the first 2-oxoamide derivative (GK317), which presents potent inhibition of GVIA iPLA2 (XI(50) value of 0.007) and at the same time significant selectivity over GIVA cPLA2 and GV sPLA2.
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Affiliation(s)
- Anneta Smyrniotou
- Chemical Laboratories, Agricultural University of Athens, Iera Odos 75, Athens 11855, Greece
| | - Maroula G Kokotou
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15771, Greece; Department of Pharmacology and Department of Chemistry and Biochemistry, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0601, USA
| | - Varnavas D Mouchlis
- Department of Pharmacology and Department of Chemistry and Biochemistry, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0601, USA
| | - Efrosini Barbayianni
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15771, Greece
| | - George Kokotos
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15771, Greece
| | - Edward A Dennis
- Department of Pharmacology and Department of Chemistry and Biochemistry, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0601, USA.
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124
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Rahmanian N, Hosseinimehr SJ, Khalaj A. The paradox role of caspase cascade in ionizing radiation therapy. J Biomed Sci 2016; 23:88. [PMID: 27923354 PMCID: PMC5142153 DOI: 10.1186/s12929-016-0306-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 11/30/2016] [Indexed: 12/19/2022] Open
Abstract
Radiotherapy alone or in combination with chemotherapy/surgery is widely used for treatment of cancers. It reduces tumor growth and prevents metastasis. While ionizing radiation activates caspase cascade resulted in apoptosis in cancer cells, it also stimulates tumor cell re-population that leads to reduce the effectiveness of the radiation therapy. This review describes the mechanisms for paradox role of caspase cascade in cancer therapy and discusses the logical and practical strategies for improvement the therapeutic index of radiotherapy through enhancement of radiosensitivity and decreasing the rate of tumor recurrence.
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Affiliation(s)
- Najmeh Rahmanian
- Department of Radiopharmacy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
- Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Seyed Jalal Hosseinimehr
- Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ali Khalaj
- Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
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125
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Translationally Controlled Tumor Protein Stimulates Dopamine Release from PC12 Cells via Ca 2+-Independent Phospholipase A₂ Pathways. Int J Mol Sci 2016; 17:ijms17101774. [PMID: 27783042 PMCID: PMC5085798 DOI: 10.3390/ijms17101774] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 10/05/2016] [Accepted: 10/10/2016] [Indexed: 11/17/2022] Open
Abstract
The translationally controlled tumor protein (TCTP), initially identified as a tumor- and growth-related protein, is also known as a histamine-releasing factor (HRF). TCTP is widely distributed in the neuronal systems, but its function is largely uncharacterized. Here, we report a novel function of TCTP in the neurotransmitter release from a neurosecretory, pheochromocytoma (PC12) cells. Treatment with recombinant TCTP (rTCTP) enhanced both basal and depolarization (50 mM KCl)-evoked [³H]dopamine release in concentration- and time-dependent manners. Interestingly, even though rTCTP induced the increase in intracellular calcium levels ([Ca2+]i), the rTCTP-driven effect on dopamine release was mediated by a Ca2+-independent pathway, as evidenced by the fact that Ca2+-modulating agents such as Ca2+ chelators and a voltage-gated L-type Ca2+-channel blocker did not produce any changes in rTCTP-evoked dopamine release. In a study to investigate the involvement of phospholipase A₂ (PLA₂) in rTCTP-induced dopamine release, the inhibitor for Ca2+-independent PLA₂ (iPLA₂) produced a significant inhibitory effect on rTCTP-induced dopamine release, whereas this release was not significantly inhibited by Ca2+-dependent cytosolic PLA₂ (cPLA₂) and secretory PLA₂ (sPLA₂) inhibitors. We found that rTCTP-induced dopamine release from neuronal PC12 cells was modulated by a Ca2+-independent mechanism that involved PLA₂ in the process, suggesting the regulatory role of TCTP in the neuronal functions.
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126
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Kokotou MG, Limnios D, Nikolaou A, Psarra A, Kokotos G. Inhibitors of phospholipase A2 and their therapeutic potential: an update on patents (2012-2016). Expert Opin Ther Pat 2016; 27:217-225. [DOI: 10.1080/13543776.2017.1246540] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Maroula G. Kokotou
- Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Dimitris Limnios
- Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Aikaterini Nikolaou
- Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Anastasia Psarra
- Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - George Kokotos
- Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
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127
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SREBP-2/PNPLA8 axis improves non-alcoholic fatty liver disease through activation of autophagy. Sci Rep 2016; 6:35732. [PMID: 27767079 PMCID: PMC5073315 DOI: 10.1038/srep35732] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 10/03/2016] [Indexed: 01/04/2023] Open
Abstract
Dysregulated autophagy is associated with steatosis and non-alcoholic fatty liver disease (NAFLD), however the mechanisms connecting them remain poorly understand. Here, we show that co-administration of lovastatin and ezetimibe (L/E) significantly reverses hepatic triglyceride accumulation concomitant with an increase in SREBP-2 driven autophagy in mice fed a high-fat diet (HFD). We further show that the statin mediated increase in SREBP-2 directly activates expression of patatin-like phospholipase domain-containing enzyme 8 (PNPLA8) gene, and PNPLA8 associates with autophagosomes and is associated with a decrease in cellular triglyceride. Moreover, we show that over-expression of PNPLA8 dramatically decreases hepatic steatosis through increased autophagy in hepatocytes of HFD-fed mice. Live-cell imaging analyses also reveal that PNPLA8 dynamically interacts with LC3 and we suggest that the SREBP-2/PNPLA8 axis represents a novel regulatory mechanism for lipid homeostasis. These data provide a possible mechanism for the reported beneficial effects of statins for decreasing hepatic triglyceride levels in NAFLD patients.
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128
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Barbour SE, Ramanadham S. Analyses of Calcium-Independent Phospholipase A 2beta (iPLA 2β) in Biological Systems. Methods Enzymol 2016; 583:119-141. [PMID: 28063488 DOI: 10.1016/bs.mie.2016.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
The Ca2+-independent phospholipases A2 (iPLA2s) are part of a diverse family of PLA2s, manifest activity in the absence of Ca2+, are ubiquitous, and participate in a variety of biological processes. Among the iPLA2s, the cytosolic iPLA2β has received considerable attention and ongoing studies from various laboratories suggest that dysregulation of iPLA2β can have a profound impact on the onset and/or progression of many diseases (e.g., cardiovascular, neurological, metabolic, autoimmune). Therefore, appropriate approaches are warranted to gain a better understanding of the role of iPLA2β in vivo and its contribution to pathophysiology. Given that iPLA2β is very labile, its basal expression is low in a number of cell systems, and that crystal structure of iPLA2β is not yet available, careful and efficient protocols are needed to appropriately assess iPLA2β biochemistry, dynamics, and membrane association. Here, step-by-step details are provided to (a) measure iPLA2β-specific activity in cell lines or tissue preparations (using a simple radiolabel-based assay) and assess the impact of stimuli and inhibitors on resting- and disease-state iPLA2β activity, (b) purify the iPLA2β to near homogeneity (via sequential chromatography) from cell line or tissue preparations, enabling concentration of the enzyme for subsequent analyses (e.g., proteomics), and (c) employ hydrogen/deuterium exchange mass spectrometry analyses to probe both the structure of iPLA2β and dynamics of its association with the membranes, substrates, and inhibitors.
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Affiliation(s)
- S E Barbour
- University of Georgia at Athens, Athens, GA, United States
| | - S Ramanadham
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, United States.
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129
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Hermansson M, Hänninen S, Hokynar K, Somerharju P. The PNPLA-family phospholipases involved in glycerophospholipid homeostasis of HeLa cells. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1058-1065. [DOI: 10.1016/j.bbalip.2016.06.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 05/25/2016] [Accepted: 06/10/2016] [Indexed: 12/17/2022]
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130
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Vasilakaki S, Barbayianni E, Magrioti V, Pastukhov O, Constantinou-Kokotou V, Huwiler A, Kokotos G. Inhibitors of secreted phospholipase A2 suppress the release of PGE2 in renal mesangial cells. Bioorg Med Chem 2016; 24:3029-3034. [PMID: 27234891 DOI: 10.1016/j.bmc.2016.05.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 05/11/2016] [Indexed: 01/15/2023]
Abstract
The upregulation of PGE2 by mesangial cells has been observed under chronic inflammation condition. In the present work, renal mesangial cells were stimulated to trigger a huge increase of PGE2 synthesis and were treated in the absence or presence of known PLA2 inhibitors. A variety of synthetic inhibitors, mainly developed in our labs, which are known to selectively inhibit each of GIVA cPLA2, GVIA iPLA2, and GIIA/GV sPLA2, were used as tools in this study. Synthetic sPLA2 inhibitors, such as GK115 (an amide derivative based on the non-natural amino acid (R)-γ-norleucine) as well as GK126 and GK241 (2-oxoamides based on the natural (S)-α-amino acid leucine and valine, respectively) presented an interesting effect on the suppression of PGE2 formation.
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Affiliation(s)
- Sofia Vasilakaki
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15771, Greece
| | - Efrosini Barbayianni
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15771, Greece
| | - Victoria Magrioti
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15771, Greece
| | | | | | - Andrea Huwiler
- Institute of Pharmacology, University of Bern, Bern 3010, Switzerland
| | - George Kokotos
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15771, Greece.
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131
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Elimam H, Papillon J, Kaufman DR, Guillemette J, Aoudjit L, Gross RW, Takano T, Cybulsky AV. Genetic Ablation of Calcium-independent Phospholipase A2γ Induces Glomerular Injury in Mice. J Biol Chem 2016; 291:14468-82. [PMID: 27226532 DOI: 10.1074/jbc.m115.696781] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Indexed: 12/15/2022] Open
Abstract
Glomerular visceral epithelial cells (podocytes) play a critical role in the maintenance of glomerular permselectivity. Podocyte injury, manifesting as proteinuria, is the cause of many glomerular diseases. We reported previously that calcium-independent phospholipase A2γ (iPLA2γ) is cytoprotective against complement-mediated glomerular epithelial cell injury. Studies in iPLA2γ KO mice have demonstrated an important role for iPLA2γ in mitochondrial lipid turnover, membrane structure, and metabolism. The aim of the present study was to employ iPLA2γ KO mice to better understand the role of iPLA2γ in normal glomerular and podocyte function as well as in glomerular injury. We show that deletion of iPLA2γ did not cause detectable albuminuria; however, it resulted in mitochondrial structural abnormalities and enhanced autophagy in podocytes as well as loss of podocytes in aging KO mice. Moreover, after induction of anti-glomerular basement membrane nephritis in young mice, iPLA2γ KO mice exhibited significantly increased levels of albuminuria, podocyte injury, and loss of podocytes compared with wild type. Thus, iPLA2γ has a protective functional role in the normal glomerulus and in glomerulonephritis. Understanding the role of iPLA2γ in glomerular pathophysiology provides opportunities for the development of novel therapeutic approaches to glomerular injury and proteinuria.
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Affiliation(s)
- Hanan Elimam
- From the Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec H4A 3J1, Canada and
| | - Joan Papillon
- From the Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec H4A 3J1, Canada and
| | - Daniel R Kaufman
- From the Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec H4A 3J1, Canada and
| | - Julie Guillemette
- From the Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec H4A 3J1, Canada and
| | - Lamine Aoudjit
- From the Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec H4A 3J1, Canada and
| | - Richard W Gross
- the Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Tomoko Takano
- From the Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec H4A 3J1, Canada and
| | - Andrey V Cybulsky
- From the Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec H4A 3J1, Canada and
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132
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Tejero J, Kapralov AA, Baumgartner MP, Sparacino-Watkins CE, Anthonymutu TS, Vlasova II, Camacho CJ, Gladwin MT, Bayir H, Kagan VE. Peroxidase activation of cytoglobin by anionic phospholipids: Mechanisms and consequences. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1861:391-401. [PMID: 26928591 PMCID: PMC4821708 DOI: 10.1016/j.bbalip.2016.02.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 02/02/2016] [Accepted: 02/24/2016] [Indexed: 10/22/2022]
Abstract
Cytoglobin (Cygb) is a hexa-coordinated hemoprotein with yet to be defined physiological functions. The iron coordination and spin state of the Cygb heme group are sensitive to oxidation of two cysteine residues (Cys38/Cys83) and/or the binding of free fatty acids. However, the roles of redox vs lipid regulators of Cygb's structural rearrangements in the context of the protein peroxidase competence are not known. Searching for physiologically relevant lipid regulators of Cygb, here we report that anionic phospholipids, particularly phosphatidylinositolphosphates, affect structural organization of the protein and modulate its iron state and peroxidase activity both conjointly and/or independently of cysteine oxidation. Thus, different anionic lipids can operate in cysteine-dependent and cysteine-independent ways as inducers of the peroxidase activity. We establish that Cygb's peroxidase activity can be utilized for the catalysis of peroxidation of anionic phospholipids (including phosphatidylinositolphosphates) yielding mono-oxygenated molecular species. Combined with the computational simulations we propose a bipartite lipid binding model that rationalizes the modes of interactions with phospholipids, the effects on structural re-arrangements and the peroxidase activity of the hemoprotein.
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Affiliation(s)
- Jesús Tejero
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA; Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA.
| | - Alexandr A Kapralov
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA; Center for Free Radical and Antioxidant Health and Center for Medical Countermeasures against Radiation, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Matthew P Baumgartner
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Courtney E Sparacino-Watkins
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA; Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Tamil S Anthonymutu
- Center for Free Radical and Antioxidant Health and Center for Medical Countermeasures against Radiation, University of Pittsburgh, Pittsburgh, PA 15219, USA; Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Irina I Vlasova
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA; Center for Free Radical and Antioxidant Health and Center for Medical Countermeasures against Radiation, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Carlos J Camacho
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Mark T Gladwin
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA; Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Hülya Bayir
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA; Center for Free Radical and Antioxidant Health and Center for Medical Countermeasures against Radiation, University of Pittsburgh, Pittsburgh, PA 15219, USA; Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA 15219, USA.
| | - Valerian E Kagan
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA; Center for Free Radical and Antioxidant Health and Center for Medical Countermeasures against Radiation, University of Pittsburgh, Pittsburgh, PA 15219, USA; Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15219, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15219, USA; Department of Radiation Oncology, University of Pittsburgh, Pittsburgh, PA 15219, USA.
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133
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Mouchlis VD, Limnios D, Kokotou MG, Barbayianni E, Kokotos G, McCammon JA, Dennis EA. Development of Potent and Selective Inhibitors for Group VIA Calcium-Independent Phospholipase A2 Guided by Molecular Dynamics and Structure-Activity Relationships. J Med Chem 2016; 59:4403-14. [PMID: 27087127 DOI: 10.1021/acs.jmedchem.6b00377] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The development of inhibitors for phospholipase A2 (PLA2) is important in elucidating the enzymes implication in various biological pathways. PLA2 enzymes are an important pharmacological target implicated in various inflammatory diseases. Computational chemistry, organic synthesis, and in vitro assays were employed to develop potent and selective inhibitors for group VIA calcium-independent PLA2. A set of fluoroketone inhibitors was studied for their binding mode with two human cytosolic PLA2 enzymes: group IVA cPLA2 and group VIA iPLA2. New compounds were synthesized and assayed toward three major PLA2s. This study led to the development of four potent and selective thioether fluoroketone inhibitors as well as a thioether keto-1,2,4-oxadiazole inhibitor for GVIA iPLA2, which will serve as lead compounds for future development and studies. The keto-1,2,4-oxadiazole functionality with a thioether is a novel structure, and it will be used as a lead to develop inhibitors with higher potency and selectivity toward GVIA iPLA2.
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Affiliation(s)
- Varnavas D Mouchlis
- Department of Pharmacology and Department of Chemistry and Biochemistry, School of Medicine, University of California, San Diego , La Jolla, California 92093-0601, United States
| | - Dimitris Limnios
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens , Panepistimiopolis, Athens 15771, Greece
| | - Maroula G Kokotou
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens , Panepistimiopolis, Athens 15771, Greece
| | - Efrosini Barbayianni
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens , Panepistimiopolis, Athens 15771, Greece
| | - George Kokotos
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens , Panepistimiopolis, Athens 15771, Greece
| | - J Andrew McCammon
- Department of Pharmacology and Department of Chemistry and Biochemistry, School of Medicine, University of California, San Diego , La Jolla, California 92093-0601, United States
| | - Edward A Dennis
- Department of Pharmacology and Department of Chemistry and Biochemistry, School of Medicine, University of California, San Diego , La Jolla, California 92093-0601, United States
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134
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Pearson GL, Mellett N, Chu KY, Boslem E, Meikle PJ, Biden TJ. A comprehensive lipidomic screen of pancreatic β-cells using mass spectroscopy defines novel features of glucose-stimulated turnover of neutral lipids, sphingolipids and plasmalogens. Mol Metab 2016; 5:404-414. [PMID: 27257600 PMCID: PMC4877660 DOI: 10.1016/j.molmet.2016.04.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/05/2016] [Accepted: 04/07/2016] [Indexed: 01/05/2023] Open
Abstract
Objective Glucose promotes lipid remodelling in pancreatic β-cells, and this is thought to contribute to the regulation of insulin secretion, but the metabolic pathways and potential signalling intermediates have not been fully elaborated. Methods Using mass spectrometry (MS) we quantified changes in approximately 300 lipid metabolites in MIN6 β-cells and isolated mouse islets following 1 h stimulation with glucose. Flux through sphingolipid pathways was also assessed in 3H-sphinganine-labelled cells using TLC. Results Glucose specifically activates the conversion of triacylglycerol (TAG) to diacylglycerol (DAG). This leads indirectly to the formation of 18:1 monoacylglycerol (MAG), via degradation of saturated/monounsaturated DAG species, such as 16:0_18:1 DAG, which are the most abundant, immediate products of glucose-stimulated TAG hydrolysis. However, 16:0-containing, di-saturated DAG species are a better direct marker of TAG hydrolysis since, unlike the 18:1-containing DAGs, they are predominately formed via this route. Using multiple reaction monitoring, we confirmed that in islets under basal conditions, 18:1 MAG is the most abundant species. We further demonstrated a novel site of glucose to enhance the conversion of ceramide to sphingomyelin (SM) and galactosylceramide (GalCer). Flux and product:precursor analyses suggest regulation of the enzyme SM synthase, which would constitute a separate mechanism for localized generation of DAG in response to glucose. Phosphatidylcholine (PC) plasmalogen (P) species, specifically those containing 20:4, 22:5 and 22:6 side chains, were also diminished in the presence of glucose, whereas the more abundant phosphatidylethanolamine plasmalogens were unchanged. Conclusion Our results highlight 18:1 MAG, GalCer, PC(P) and DAG/SM as potential contributors to metabolic stimulus-secretion coupling. Using mass spectroscopy lipidomics we have defined new aspects of glucose simulated lipid turnover in pancreatic beta cells. Glucose directly stimulates triacylglycerol hydrolysis, of which di-saturated diacylglycerol species are excellent markers. C18:1 is the most abundant monacylglycerol, and the one most obviously increased by glucose. Phosphatidylcholine plasmalogens with poly-unsaturated side chains are preferentially decreased by glucose. Glucose specifically enhances the conversion of ceramide to both sphingomyelin and galactosylceramide.
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Key Words
- (O), ether lipid
- (P), plasmalogen
- ATGL, adipose tissue glycerolipase
- CE, cholesterol ester
- COH, free cholesterol
- Ceramide
- DAG, diacylglycerol
- Diacylglycerol
- FA, fatty acid
- GSIS, glucose-stimulated insulin secretion
- GalCer, galactosylceramide
- GluCer, glucosylceramide
- HSL, hormone sensitive lipase
- Insulin secretion
- KRHB, Krebs Ringer Hepes Buffer
- MAG, monacylglycerol
- MHC, monohexosylceramide
- MS, mass spectrometry
- Monacylglycerol
- PC, phosphatidylcholine
- PE, phosphatidylethanolamine
- PI, phosphatidylinositol
- PKD, protein kinase D
- PLA2, phospholipase A2
- Pancreatic β-cell
- Plasmalogen
- SM, sphingomyelin
- TAG, triacylglycerol
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Affiliation(s)
- Gemma L Pearson
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW, 2010, Australia; St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Australia
| | - Natalie Mellett
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Kwan Yi Chu
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW, 2010, Australia
| | - Ebru Boslem
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW, 2010, Australia; St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Australia
| | - Peter J Meikle
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia.
| | - Trevor J Biden
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW, 2010, Australia; St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Australia.
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135
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Deng X, Wang J, Jiao L, Utaipan T, Tuma-Kellner S, Schmitz G, Liebisch G, Stremmel W, Chamulitrat W. iPLA2β deficiency attenuates obesity and hepatic steatosis in ob/ob mice through hepatic fatty-acyl phospholipid remodeling. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:449-61. [PMID: 26873633 DOI: 10.1016/j.bbalip.2016.02.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 02/01/2016] [Accepted: 02/06/2016] [Indexed: 01/12/2023]
Abstract
PLA2G6 or GVIA calcium-independent PLA2 (iPLA2β) is identified as one of the NAFLD modifier genes in humans, and thought to be a target for NAFLD therapy. iPLA2β is known to play a house-keeping role in phospholipid metabolism and remodeling. However, its role in NAFLD pathogenesis has not been supported by results obtained from high-fat feeding of iPLA2β-null (PKO) mice. Unlike livers of human NAFLD and genetically obese rodents, fatty liver induced by high-fat diet is not associated with depletion of hepatic phospholipids. We therefore tested whether iPLA2β could regulate obesity and hepatic steatosis in leptin-deficient mice by cross-breeding PKO with ob/ob mice to generate ob/ob-PKO mice. Here we observed an improvement in ob/ob-PKO mice with significant reduction in serum enzymes, lipids, glucose, insulin as well as improved glucose tolerance, and reduction in islet hyperplasia. The improvement in hepatic steatosis measured by liver triglycerides, fatty acids and cholesterol esters was associated with decreased expression of PPARγ and de novo lipogenesis genes, and the reversal of β-oxidation gene expression. Notably, ob/ob livers contained depleted levels of lysophospholipids and phospholipids, and iPLA2β deficiency in ob/ob-PKO livers lowers the former, but replenished the latter particularly phosphatidylethanolamine (PE) and phosphatidylcholine (PC) that contained arachidonic (AA) and docosahexaenoic (DHA) acids. Compared with WT livers, PKO livers also contained increased PE and PC containing AA and DHA. Thus, iPLA2β deficiency protected against obesity and ob/ob fatty liver which was associated with hepatic fatty-acyl phospholipid remodeling. Our results support the deleterious role of iPLA2β in severe obesity associated NAFLD.
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Affiliation(s)
- Xiuling Deng
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022 Wuhan, China
| | - Jiliang Wang
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Li Jiao
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Tanyarath Utaipan
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Sabine Tuma-Kellner
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Gerd Schmitz
- Institute of Clinical Chemistry and Laboratory Medicine, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Gerhard Liebisch
- Institute of Clinical Chemistry and Laboratory Medicine, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Wolfgang Stremmel
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Walee Chamulitrat
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany.
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King MA, Clanton TL, Laitano O. Hyperthermia, dehydration, and osmotic stress: unconventional sources of exercise-induced reactive oxygen species. Am J Physiol Regul Integr Comp Physiol 2016; 310:R105-14. [DOI: 10.1152/ajpregu.00395.2015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 11/10/2015] [Indexed: 12/17/2022]
Abstract
Evidence of increased reactive oxygen species (ROS) production is observed in the circulation during exercise in humans. This is exacerbated at elevated body temperatures and attenuated when normal exercise-induced body temperature elevations are suppressed. Why ROS production during exercise is temperature dependent is entirely unknown. This review covers the human exercise studies to date that provide evidence that oxidant and antioxidant changes observed in the blood during exercise are dependent on temperature and fluid balance. We then address possible mechanisms linking exercise with these variables that include shear stress, effects of hemoconcentration, and signaling pathways involving muscle osmoregulation. Since pathways of muscle osmoregulation are rarely discussed in this context, we provide a brief review of what is currently known and unknown about muscle osmoregulation and how it may be linked to oxidant production in exercise and hyperthermia. Both the circulation and the exercising muscle fibers become concentrated with osmolytes during exercise in the heat, resulting in a competition for available water across the muscle sarcolemma and other tissues. We conclude that though multiple mechanisms may be responsible for the changes in oxidant/antioxidant balance in the blood during exercise, a strong case can be made that a significant component of ROS produced during some forms of exercise reflect requirements of adapting to osmotic challenges, hyperthermia challenges, and loss of circulating fluid volume.
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Affiliation(s)
| | | | - Orlando Laitano
- University of Florida, Applied Physiology and Kinesiology, and
- Universidade Federal do Vale do São Francisco, Colegiado de Educação Física, Brazil
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Inhoffen J, Tuma-Kellner S, Straub B, Stremmel W, Chamulitrat W. Deficiency of iPLA₂β Primes Immune Cells for Proinflammation: Potential Involvement in Age-Related Mesenteric Lymph Node Lymphoma. Cancers (Basel) 2015; 7:2427-42. [PMID: 26690222 PMCID: PMC4695901 DOI: 10.3390/cancers7040901] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 11/26/2015] [Accepted: 12/01/2015] [Indexed: 12/12/2022] Open
Abstract
Proinflammation can predispose the body to autoimmunity and cancer. We have reported that iPLA2β−/− mice are susceptible to autoimmune hepatitis and colitis. Here we determined whether cytokine release by immune cells could be affected by iPLA2β deficiency alone or combined with CD95/FasL-antibody treatment in vivo. We also determined whether cancer risk could be increased in aged mutant mice. Immune cells were isolated from 3-month old male WT and iPLA2β−/− mice, and some were injected with anti-CD95/FasL antibody for 6 h. Kupffer cells (KC) or splenocytes and liver lymphocytes were stimulated in vitro by lipopolysaccharide or concanavalinA, respectively. Whole-body iPLA2β deficiency caused increased apoptosis in liver, spleen, and mesenteric lymph node (MLN). KC from mutant mice showed suppressed release of TNFα and IL-6, while their splenocytes secreted increased levels of IFNγ and IL-17a. Upon CD95/FasL activation, the mutant KC in turn showed exaggerated cytokine release, this was accompanied by an increased release of IFNγ and IL-17a by liver lymphocytes. Aged iPLA2β−/− mice did not show follicular MLN lymphoma commonly seen in aged C57/BL6 mice. Thus, iPLA2β deficiency renders M1- and Th1/Th17-proinflammation potentially leading to a reduction in age-related MLN lymphoma during aging.
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Affiliation(s)
- Johannes Inhoffen
- Department of Internal Medicine IV, University Heidelberg Hospital, 69120 Heidelberg, Germany.
| | - Sabine Tuma-Kellner
- Department of Internal Medicine IV, University Heidelberg Hospital, 69120 Heidelberg, Germany.
| | - Beate Straub
- Pathology Institute of Medical Faculty Heidelberg, 69120 Heidelberg, Germany.
| | - Wolfgang Stremmel
- Department of Internal Medicine IV, University Heidelberg Hospital, 69120 Heidelberg, Germany.
| | - Walee Chamulitrat
- Department of Internal Medicine IV, University Heidelberg Hospital, 69120 Heidelberg, Germany.
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Petan T, Križaj I. Is iPLA2β a Novel Target for the Development of New Strategies to Alleviate Inflammatory Bowel Disease? Dig Dis Sci 2015; 60:3504-6. [PMID: 26391270 DOI: 10.1007/s10620-015-3874-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Affiliation(s)
- Toni Petan
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia.
| | - Igor Križaj
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia. .,Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000, Ljubljana, Slovenia.
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Dennis EA. Introduction to Thematic Review Series: Phospholipases: Central Role in Lipid Signaling and Disease. J Lipid Res 2015; 56:1245-7. [PMID: 26031662 PMCID: PMC4479329 DOI: 10.1194/jlr.e061101] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Edward A. Dennis
- Department of Chemistry and Biochemistry and Department of Pharmacology, School of Medicine, University of California at San Diego, La Jolla, CA 92093-0601
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