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Gwak YS, Chen G, Abdi S, Kim HK. Calcium-independent phospholipase A2 inhibitor produces an analgesic effect in a rat model of neuropathic pain by reducing central sensitization in the dorsal horn. Neurol Res 2021; 43:683-692. [PMID: 33866950 DOI: 10.1080/01616412.2021.1915079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Phospholipase A2 (PLA2) plays an important role in regulating the production of arachidonic acid and various eicosanoids. The aim of our study was to investigate the analgesic mechanisms of calcium-dependent cytosolic phospholipase A2 and calcium-independent PLA2 (iPLA2) inhibitors in the spinal cord in a rat model of neuropathic pain. METHODS Lumbar 5 spinal nerve ligation was performed in male Sprague-Dawley rats to develop a peripheral neuropathic pain model. Paw withdrawal thresholds in response to von Frey filaments, brush, pressure, and pinch were measured. Lumbar wide dynamic range neuronal firing rates and iPLA2 subtype expression were measured by in vivo extracellular recording and double immunofluorescence staining, respectively. RESULTS In our rat models, oral administration of prednisolone, a non-selective PLA2 inhibitor, and intrathecal injection of bromoenolactone, a iPLA2 inhibitor, significantly increased the ipsilateral hindpaw withdrawal thresholds in response to von Frey filament stimulation, but intrathecal injection of arachidonyl trifluoromethyl ketone, a selective cytosolic PLA2 inhibitor, did not show significant changes. In spinal dorsal horn neurons, bromoenolactone reduced neuronal firing rates in response to withdrawal stimulation and spontaneous firing rates in the ipsilateral side of the spinal dorsal horn. In addition, the expression of iPLA2 was co-localized with astrocytes and neurons on the ipsilateral side of the dorsal horn in rats that underwent spinal nerve ligation. DISCUSSION These data suggest that selective iPLA2 inhibitor produce analgesia in neuropathic rats by reducing central sensitization in the dorsal horn.
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Affiliation(s)
- Young Seob Gwak
- Department of Anesthesiology and Perioperative Care, University of California, Irvine, CA, USA
| | - Guanxing Chen
- Department of Pain Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Salahadin Abdi
- Department of Pain Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Hee Kee Kim
- Department of Pain Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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2
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Hua Y, Yang B, Chen Q, Zhang J, Hu J, Fan Y. Activation of α7 Nicotinic Acetylcholine Receptor Protects Against 1-Methyl-4-Phenylpyridinium-Induced Astroglial Apoptosis. Front Cell Neurosci 2019; 13:507. [PMID: 31780901 PMCID: PMC6861188 DOI: 10.3389/fncel.2019.00507] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 10/28/2019] [Indexed: 01/13/2023] Open
Abstract
Astrocytes, as the largest population of glial subtype, play crucial roles in normal brain function and pathological conditions, such as Parkinson's disease (PD). Restoring the functions of astrocyte is a promising new therapeutic target for PD. Astrocytes can express multiple types of neurotransmitter receptors, including functional α7 nicotinic acetylcholine receptor (α7nAChR). Previously, we found that a non-selective α7nAChR agonist nicotine exerted a protective effect against H2O2-induced astrocyte apoptosis via an α7nAChR-dependent pathway. However, the molecular mechanism of the antiapoptotic response of astroglial α7nAChR has not been studied. In the present study, using pharmacological inhibition and genetic knockout of α7nAChR, we assessed the antiapoptotic effects of an α7nAChR agonist PNU-282987 in primary cultured astrocytes treated with 1-methyl-4-phenylpyridinium (MPP+). PNU-282987 promoted the viability of astrocytes, alleviated MPP+ induced apoptosis, and decreased the number of GFAP+/TUNEL+ cells. Meanwhile, PNU-282987 upregulated the expression of the antiapoptotic protein Bcl-2 and downregulated the expression of the apoptotic protein Bax and cleaved-caspase-3. Moreover, the suppression of the JNK-p53-caspase-3 signaling may underlie the neuroprotective property of PNU-282987. Therefore, PNU-282987 ameliorates astroglial apoptosis induced by MPP+ through α7nAChR-JNK-p53 signaling. Our findings suggest that PNU-282987 may be a potential drug for restoring astroglial functions in the treatment of PD.
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Affiliation(s)
- Ye Hua
- Department of Neurology, The Affiliated Wuxi No. 2 People's Hospital of Nanjing Medical University, Wuxi, China
| | - Beibei Yang
- Department of Pharmacology, Neuroprotective Drug Discovery Center, Nanjing Medical University, Nanjing, China
| | - Qiang Chen
- Department of Pharmacology, Neuroprotective Drug Discovery Center, Nanjing Medical University, Nanjing, China
| | - Ji Zhang
- Division of Clinical Pharmacy, Department of Pharmacy, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Jun Hu
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yi Fan
- Department of Pharmacology, Neuroprotective Drug Discovery Center, Nanjing Medical University, Nanjing, China
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Wang ZB, Liu JY, Xu XJ, Mao XY, Zhang W, Zhou HH, Liu ZQ. Neurodegeneration with brain iron accumulation: Insights into the mitochondria dysregulation. Biomed Pharmacother 2019; 118:109068. [PMID: 31404774 DOI: 10.1016/j.biopha.2019.109068] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/31/2019] [Accepted: 05/31/2019] [Indexed: 12/16/2022] Open
Abstract
NBIA (Neurodegeneration with brain iron accumulation) is a group of inherited neurologic disorders characterized by marked genetic heterogeneity, in which iron atypical accumulates in basal ganglia resulting in brain magnetic resonance imaging changes, histopathological abnormalities, and neuropsychiatric clinical symptoms. With the rapid development of high-throughput sequencing technologies, ten candidate genes have been identified, including PANK2, PLA2G6, C19orf12, WDR45, FA2H, ATP13A2, FTL, CP, C2orf37, and COASY. They are involved in seemingly unrelated cellular pathways, such as iron homeostasis (FTL, CP), lipid metabolism (PLA2G6, C19orf12, FA2H), Coenzyme A synthesis (PANK2, COASY), and autophagy (WDR45, ATP13A2). In particular, PANK2, COASY, PLA2G6, and C19orf12 are located on mitochondria, which associate with certain subtypes of NBIA showing mitochondria dysregulation. However, the relationships among those four genes are still unclear. Therefore, this review is specifically focused on dysregulation of mitochondria in NBIA and afore-mentioned four genes, with summaries of both pathological and clinical findings.
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Affiliation(s)
- Zhi-Bin Wang
- Departments of Clinical Pharmacology and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, PR China; Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha 410078, PR China
| | - Jun-Yan Liu
- Department of Orthopaedics, The First Affiliated Hospital of the University of South China, Hengyang 421001, PR China
| | - Xiao-Jing Xu
- Departments of Clinical Pharmacology and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, PR China; Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha 410078, PR China
| | - Xiao-Yuan Mao
- Departments of Clinical Pharmacology and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, PR China; Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha 410078, PR China
| | - Wei Zhang
- Departments of Clinical Pharmacology and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, PR China; Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha 410078, PR China
| | - Hong-Hao Zhou
- Departments of Clinical Pharmacology and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, PR China; Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha 410078, PR China
| | - Zhao-Qian Liu
- Departments of Clinical Pharmacology and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, PR China; Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha 410078, PR China.
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Qasem H, Al-Ayadhi L, Bjørklund G, Chirumbolo S, El-Ansary A. Impaired lipid metabolism markers to assess the risk of neuroinflammation in autism spectrum disorder. Metab Brain Dis 2018; 33:1141-1153. [PMID: 29569150 DOI: 10.1007/s11011-018-0206-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 02/19/2018] [Indexed: 01/19/2023]
Abstract
Autism spectrum disorder (ASD) is a multifactorial disorder caused by an interaction between environmental risk factors and a genetic background. It is characterized by impairment in communication, social interaction, repetitive behavior, and sensory processing. The etiology of ASD is still not fully understood, and the role of neuroinflammation in autism behaviors needs to be further investigated. The aim of the present study was to test the possible association between prostaglandin E2 (PGE2), cyclooxygenase-2 (COX-2), microsomal prostaglandin E synthase-1 (mPGES-1), prostaglandin PGE2 EP2 receptors and nuclear kappa B (NF-κB) and the severity of cognitive disorders, social impairment, and sensory dysfunction. PGE2, COX-2, mPGES-1, PGE2-EP2 receptors and NF-κB as biochemical parameters related to neuroinflammation were determined in the plasma of 47 Saudi male patients with ASD, categorized as mild to moderate and severe as indicated by the Childhood Autism Rating Scale (CARS) or the Social Responsiveness Scale (SRS) or the Short Sensory Profile (SSP) and compared to 46 neurotypical controls. The data indicated that ASD patients have remarkably higher levels of the measured parameters compared to neurotypical controls, except for EP2 receptors that showed an opposite trend. While the measured parameter did not correlate with the severity of social and cognitive dysfunction, PGE2, COX-2, and mPGES-1 were remarkably associated with the dysfunction in sensory processing. NF-κB was significantly increased in relation to age. Based on the discussed data, the positive correlation between PGE2, COX-2, and mPGES-1 confirm the role of PGE2 pathway and neuroinflammation in the etiology of ASD, and the possibility of using PGE2, COX-2 and mPGES-1 as biomarkers of autism severity. NF-κB as inflammatory inducer showed an elevated level in plasma of ASD individuals. Receiver operating characteristic analysis together with predictiveness diagrams proved that the measured parameters could be used as predictive biomarkers of biochemical correlates to ASD.
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Affiliation(s)
- Hanan Qasem
- Biochemistry Department, Science College, King Saud University, Riyadh, Saudi Arabia
| | - Laila Al-Ayadhi
- Autism Research and Treatment Center, Riyadh, Saudi Arabia
- Shaik AL-Amodi Autism Research Chair, King Saud University, Riyadh, Saudi Arabia
- Physiology Department, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Mo i Rana, Norway
| | - Salvatore Chirumbolo
- Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
| | - Afaf El-Ansary
- Autism Research and Treatment Center, Riyadh, Saudi Arabia.
- Shaik AL-Amodi Autism Research Chair, King Saud University, Riyadh, Saudi Arabia.
- Central laboratory, Female Centre for Scientific and Medical Studies, King Saud University, Riyadh, Saudi Arabia.
- Therapeutic Chemistry Department, National Research Center, Dokki, Guiza, Egypt.
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Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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6
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Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 952] [Impact Index Per Article: 158.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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7
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Misslin C, Velasco-Estevez M, Albert M, O’Sullivan SA, Dev KK. Phospholipase A2 is involved in galactosylsphingosine-induced astrocyte toxicity, neuronal damage and demyelination. PLoS One 2017; 12:e0187217. [PMID: 29095858 PMCID: PMC5667767 DOI: 10.1371/journal.pone.0187217] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 10/16/2017] [Indexed: 11/29/2022] Open
Abstract
Krabbe disease is a fatal rare inherited lipid storage disorder affecting 1:100,000 births. This illness is caused by mutations in the galc gene encoding for the enzyme galactosylceramidase (GALC). Dysfunction of GALC has been linked to the toxic build-up of the galactolipid, galactosylsphingosine (psychosine), which induces cell death of oligodendrocytes. Previous studies show that phospholipase A2 (PLA2) may play a role in psychosine induce cell death. Here, we demonstrate that non-selective inhibition of cPLA2/sPLA2 and selective inhibition of cPLA2, but not sPLA2, also attenuates psychosine-induced cell death of human astrocytes. This study shows that extracellular calcium is required for psychosine induced cell death, but intracellular calcium release, reactive oxygen species or release of soluble factors are not involved. These findings suggest a cell autonomous effect, at least in human astrocytes. Supporting a role for PLA2 in psychosine-induced cell death of oligodendrocytes and astrocytes, the results show inhibition of PLA2 attenuates psychosine-induced decrease in the expression of astrocyte marker vimentin as well as myelin basic protein (MBP), myelin oligodendrocyte glycoprotein (MOG) and the neuronal marker SMI-32 in organotypic slice cultures. These findings provide further mechanistic details of psychosine-induced death of glia and suggest a role for PLA2 in the process. This work also supports the proposal that novel drugs for Krabbe disease may require testing on astrocytes as well as oligodendrocytes for more holistic prediction of pre-clinical and clinical efficacy.
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Affiliation(s)
- Cedric Misslin
- Drug Development, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | | | - Marie Albert
- Drug Development, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | | | - Kumlesh K. Dev
- Drug Development, School of Medicine, Trinity College Dublin, Dublin, Ireland
- * E-mail:
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8
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Booth HDE, Hirst WD, Wade-Martins R. The Role of Astrocyte Dysfunction in Parkinson's Disease Pathogenesis. Trends Neurosci 2017; 40:358-370. [PMID: 28527591 PMCID: PMC5462417 DOI: 10.1016/j.tins.2017.04.001] [Citation(s) in RCA: 376] [Impact Index Per Article: 53.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 04/13/2017] [Accepted: 04/14/2017] [Indexed: 02/07/2023]
Abstract
Astrocytes are the most populous glial subtype and are critical for brain function. Despite this, historically there have been few studies into the role that they may have in neurodegenerative diseases, such as Parkinson's disease (PD). Recently, however, several studies have determined that genes known to have a causative role in the development of PD are expressed in astrocytes and have important roles in astrocyte function. Here, we review these recent developments and discuss their impact on our understanding of the pathophysiology of PD, and the implications that this might have for its treatment.
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Affiliation(s)
- Heather D E Booth
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK; Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | | | - Richard Wade-Martins
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK; Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
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Aizawa F, Nishinaka T, Yamashita T, Nakamoto K, Koyama Y, Kasuya F, Tokuyama S. Astrocytes Release Polyunsaturated Fatty Acids by Lipopolysaccharide Stimuli. Biol Pharm Bull 2017; 39:1100-6. [PMID: 27374285 DOI: 10.1248/bpb.b15-01037] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously reported that levels of long-chain fatty acids (FAs) including docosahexaenoic acids (DHA) increase in the hypothalamus of inflammatory pain model mice. However, the precise mechanisms underlying the increment of free fatty acids (FFAs) in the brain during inflammation remains unknown. In this study, we characterized FFAs released by inflammatory stimulation in rat primary cultured astrocytes, and tested the involvement of phospholipase A2 (PLA2) on these mechanisms. Lipopolysaccharide (LPS) stimulation significantly increased the levels of several FAs in the astrocytes. Under these conditions, mRNA expression of cytosolic PLA2 (cPLA2) and calcium-independent PLA2 (iPLA2) in LPS-treated group increased compared with the control group. Furthermore, in the culture media, the levels of DHA and arachidonic acid (ARA) significantly increased by LPS stimuli compared with those of a vehicle-treated control group whereas the levels of saturated FAs (SFAs), namely palmitic acid (PAM) and stearic acid (STA), did not change. In summary, our findings suggest that astrocytes specifically release DHA and ARA by inflammatory conditions. Therefore astrocytes might function as a regulatory factor of DHA and ARA in the brain.
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Affiliation(s)
- Fuka Aizawa
- Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Kobe Gakuin University
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Hashimoto T, Fang YI, Ohata H, Honda K. Change in soluble epoxide hydrolase (sEH) during cisplatin-induced acute renal failure in mice. J Toxicol Sci 2016; 40:451-7. [PMID: 26165641 DOI: 10.2131/jts.40.451] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Cisplatin is one of the most effective chemotherapeutic agents against various types of cancers; however, it is also associated with nephrotoxicity. Recently, it was reported that inflammatory mechanisms play a key role in the development of nephrotoxicity. Epoxyeicosatrienoic acids (EETs) have an anti-inflammatory effect and are metabolized by soluble epoxide hydrolase (sEH: encoded by EPHX2 gene). Here, we determined the change in sEH activity and EPHX2 expression in renal tissue associated with the development of cisplatin-induced nephrotoxicity. Cisplatin administration decreased hydrolase activity accompanied by down-regulation of sEH and EPHX2 expression. The down-regulation occurred prior to the elevation of blood urea nitrogen (BUN) and tumor necrosis factor-α (TNF-α) gene expression or at treatment with low dose cisplatin. In addition, a negative correlation was found between EPHX2 expression and renal thiobarbituric acid reactive substance (TBARS), and edaravone, a radical scavenger, administration did not down-regulate expression of this gene. The results of this study suggest that cisplatin decreased sEH activity through the down-regulation of sEH and EPHX2 expression, and this down-regulation was involved in a negative feedback loop to protect renal tissue from further damage. Thus, sEH is a potential therapeutic target of cisplatin-induced nephrotoxicity.
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Affiliation(s)
- Terumasa Hashimoto
- Division of Pharmacology, Department of Pharmacology, Toxicology & Therapeutics, School of Pharmacy, Showa University
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Verkhratsky A, Matteoli M, Parpura V, Mothet JP, Zorec R. Astrocytes as secretory cells of the central nervous system: idiosyncrasies of vesicular secretion. EMBO J 2016; 35:239-57. [PMID: 26758544 DOI: 10.15252/embj.201592705] [Citation(s) in RCA: 285] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/01/2015] [Indexed: 11/09/2022] Open
Abstract
Astrocytes are housekeepers of the central nervous system (CNS) and are important for CNS development, homeostasis and defence. They communicate with neurones and other glial cells through the release of signalling molecules. Astrocytes secrete a wide array of classic neurotransmitters, neuromodulators and hormones, as well as metabolic, trophic and plastic factors, all of which contribute to the gliocrine system. The release of neuroactive substances from astrocytes occurs through several distinct pathways that include diffusion through plasmalemmal channels, translocation by multiple transporters and regulated exocytosis. As in other eukaryotic cells, exocytotic secretion from astrocytes involves divergent secretory organelles (synaptic-like microvesicles, dense-core vesicles, lysosomes, exosomes and ectosomes), which differ in size, origin, cargo, membrane composition, dynamics and functions. In this review, we summarize the features and functions of secretory organelles in astrocytes. We focus on the biogenesis and trafficking of secretory organelles and on the regulation of the exocytotic secretory system in the context of healthy and diseased astrocytes.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, UK Achucarro Center for Neuroscience, IKERBASQUE Basque Foundation for Science, Bilbao, Spain Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain University of Nizhny Novgorod, Nizhny Novgorod, Russia Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology University of Ljubljana, Ljubljana, Slovenia Celica BIOMEDICAL, Ljubljana, Slovenia
| | - Michela Matteoli
- CNR Institute of Neuroscience, Milano, Italy Humanitas Research Hospital, Rozzano, Italy
| | - Vladimir Parpura
- Department of Neurobiology, Civitan International Research Center and Center for Glial Biology in Medicine, Evelyn F. McKnight Brain Institute, Atomic Force Microscopy & Nanotechnology Laboratories University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jean-Pierre Mothet
- Team Gliotransmission & Synaptopathies, Aix-Marseille University CNRS, CRN2M UMR7286, Marseille, France
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology University of Ljubljana, Ljubljana, Slovenia Celica BIOMEDICAL, Ljubljana, Slovenia
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Klosinski LP, Yao J, Yin F, Fonteh AN, Harrington MG, Christensen TA, Trushina E, Brinton RD. White Matter Lipids as a Ketogenic Fuel Supply in Aging Female Brain: Implications for Alzheimer's Disease. EBioMedicine 2015; 2:1888-904. [PMID: 26844268 PMCID: PMC4703712 DOI: 10.1016/j.ebiom.2015.11.002] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 10/24/2015] [Accepted: 11/02/2015] [Indexed: 01/28/2023] Open
Abstract
White matter degeneration is a pathological hallmark of neurodegenerative diseases including Alzheimer's. Age remains the greatest risk factor for Alzheimer's and the prevalence of age-related late onset Alzheimer's is greatest in females. We investigated mechanisms underlying white matter degeneration in an animal model consistent with the sex at greatest Alzheimer's risk. Results of these analyses demonstrated decline in mitochondrial respiration, increased mitochondrial hydrogen peroxide production and cytosolic-phospholipase-A2 sphingomyelinase pathway activation during female brain aging. Electron microscopic and lipidomic analyses confirmed myelin degeneration. An increase in fatty acids and mitochondrial fatty acid metabolism machinery was coincident with a rise in brain ketone bodies and decline in plasma ketone bodies. This mechanistic pathway and its chronologically phased activation, links mitochondrial dysfunction early in aging with later age development of white matter degeneration. The catabolism of myelin lipids to generate ketone bodies can be viewed as a systems level adaptive response to address brain fuel and energy demand. Elucidation of the initiating factors and the mechanistic pathway leading to white matter catabolism in the aging female brain provides potential therapeutic targets to prevent and treat demyelinating diseases such as Alzheimer's and multiple sclerosis. Targeting stages of disease and associated mechanisms will be critical. Mitochondrial dysfunction activates mechanisms for catabolism of myelin lipids to generate ketone bodies for ATP production. Mechanisms leading to ketone body driven energy production in brain coincide with stages of reproductive aging in females. Sequential activation of myelin catabolism pathway during aging provides multiple therapeutic targets and windows of efficacy.
The mechanisms underlying white matter degeneration, a hallmark of multiple neurodegenerative diseases including Alzheimer's, remain unclear. Herein we provide a mechanistic pathway, spanning multiple transitions of aging, that links mitochondrial dysfunction early in aging with later age white matter degeneration. Catabolism of myelin lipids to generate ketone bodies can be viewed as an adaptive survival response to address brain fuel and energy demand. Women are at greatest risk of late-onset-AD, thus, our analyses in female brain address mechanisms of AD pathology and therapeutic targets to prevent, delay and treat AD in the sex most affected with potential relevance to men.
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Key Words
- ABAD, Aβ-binding alcohol dehydrogenase
- ABAD, Aβ-binding-alcohol-dehydrogenase
- ACER3, alkaline ceramidase
- AD, Alzheimer's disease
- APO-ε4, apolipoprotein ε4
- APP, amyloid precursor protein
- Aging oxidative stress
- Alzheimer's disease
- BACE1, beta-secretase 1
- BBB, blood brain barrier
- CC, corpus callosum
- CMRglu, cerebral glucose metabolic rate
- COX, complex IV cytochrome c oxidase
- CPT1, carnitine palmitoyltransferase 1
- Cldn11, claudin 11
- Cyp2j6, arachidonic acid epoxygenase
- Cytosolic phospholipase A2
- DHA, docosahexaesnoic acid
- Erbb3, Erb-B2 receptor tyrosine kinase 3
- FDG-PET, 2-[18F]fluoro-2-deoxy-d-glucose
- GFAP, glial fibrillary acidic protein
- H2O2, hydrogen peroxide
- HADHA, hydroxyacyl-CoA dehydrogenase
- HK, hexokinase
- Ketone bodies
- LC MS, liquid chromatography mass spectrometer
- MAG, myelin associated glycoprotein
- MBP, myelin basic protein
- MCT1, monocarboxylate transporter 1
- MIB, mitochondrial isolation buffer
- MOG, myelin oligodendrocyte glycoprotein
- MTL, medial temporal lobe
- Mitochondria
- NEFA, nonesterified fatty acids
- Neurodegeneration
- OCR, oxygen consumption rate
- Olig2, oligodendrocyte transcription factor
- PB, phosphate buffer
- PCC, posterior cingulate
- PCR, polymerase chain reaction
- PDH, pyruvate dehydrogenase
- PEI, polyethyleneimine
- RCR, respiratory control ratio
- ROS, reactive oxygen species
- S1P, sphingosine
- TLDA, TaqMan low density array
- WM, white matter
- WT, wild type
- White matter
- cPLA2, cytosolic phospholipase A2
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Affiliation(s)
- Lauren P Klosinski
- Department of Neuroscience, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA, USA
| | - Jia Yao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Fei Yin
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | | | | | | | - Eugenia Trushina
- Department of Neurology, Mayo Clinic Rochester, MN, USA; Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Roberta Diaz Brinton
- Department of Neuroscience, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA, USA; Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA; Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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13
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Chuang DY, Simonyi A, Kotzbauer PT, Gu Z, Sun GY. Cytosolic phospholipase A2 plays a crucial role in ROS/NO signaling during microglial activation through the lipoxygenase pathway. J Neuroinflammation 2015; 12:199. [PMID: 26520095 PMCID: PMC4628268 DOI: 10.1186/s12974-015-0419-0] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 10/21/2015] [Indexed: 11/10/2022] Open
Abstract
Background Oxidative stress and inflammation are important factors contributing to the pathophysiology of numerous neurological disorders, including Alzheimer’s disease, Parkinson’s disease, acute stroke, and infections of the brain. There is well-established evidence that proinflammatory cytokines and glutamate, as well as reactive oxygen species (ROS) and nitric oxide (NO), are produced upon microglia activation, and these are important factors contributing to inflammatory responses and cytotoxic damage to surrounding neurons and neighboring cells. Microglial cells express relatively high levels of cytosolic phospholipase A2 (cPLA2), an enzyme known to regulate membrane phospholipid homeostasis and release of arachidonic acid (AA) for synthesis of eicosanoids. The goal for this study is to elucidate the role of cPLA2IV in mediating the oxidative and inflammatory responses in microglial cells. Methods Experiments involved primary microglia cells isolated from transgenic mice deficient in cPLA2α or iPLA2β, as well as murine immortalized BV-2 microglial cells. Inhibitors of cPLA2/iPLA2/cyclooxygenase (COX)/lipoxygenase (LOX) were used in BV-2 microglial cell line. siRNA transfection was employed to knockdown cPLA2 expression in BV-2 cells. Griess reaction protocol was used to determine NO concentration, and CM-H2DCF-DA was used to detect ROS production in primary microglia and BV-2 cells. WST-1 assay was used to assess cell viability. Western blotting was used to assess protein expression levels. Immunocytochemical staining for phalloidin against F-actin was used to demonstrate cell morphology. Results In both primary and BV-2 microglial cells, stimulation with lipopolysaccharide (LPS) or interferon gamma (IFNγ) resulted in a time-dependent increase in phosphorylation of cPLA2 together with ERK1/2. In BV-2 cells, LPS- and IFNγ-induced ROS and NO production was inhibited by arachidonyl trifluoromethyl ketone (AACOCF3) and pyrrophenone as well as RNA interference, but not BEL, suggesting a link between cPLA2, and not iPLA2, on LPS/IFNγ-induced nitrosative and oxidative stress in microglial cells. Primary microglial cells isolated from cPLA2α-deficient mice generated significantly less NO and ROS as compared with the wild-type mice. Microglia isolated from iPLA2β-deficient mice did not show a decrease in LPS-induced NO and ROS production. LPS/IFNγ induced morphological changes in primary microglia, and these changes were mitigated by AACOCF3. Interestingly, despite that LPS and IFNγ induced an increase in phospho-cPLA2 and prostaglandin E2 (PGE2) release, LPS- and IFNγ-induced NO and ROS production were not altered by the COX-1/2 inhibitor but were suppressed by the LOX-12 and LOX-15 inhibitors instead. Conclusions In summary, the results in this study demonstrated the role of cPLA2 in microglial activation with metabolic links to oxidative and inflammatory responses, and this was in part regulated by the AA metabolic pathways, namely the LOXs. Further studies with targeted inhibition of cPLA2/LOX in microglia during neuroinflammatory conditions can be valuable to investigate the therapeutic potential in ameliorating neurological disease pathology. Electronic supplementary material The online version of this article (doi:10.1186/s12974-015-0419-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Dennis Y Chuang
- Interdisciplinary Neuroscience Program, University of Missouri, Columbia, MO, USA.,Center for Translational Neuroscience, University of Missouri, Columbia, MO, USA.,Center for Botanical Interaction Studies, University of Missouri, Columbia, MO, USA
| | - Agnes Simonyi
- Center for Translational Neuroscience, University of Missouri, Columbia, MO, USA.,Center for Botanical Interaction Studies, University of Missouri, Columbia, MO, USA.,Department of Biochemistry, University of Missouri, Columbia, MO, USA
| | - Paul T Kotzbauer
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Zezong Gu
- Interdisciplinary Neuroscience Program, University of Missouri, Columbia, MO, USA.,Center for Translational Neuroscience, University of Missouri, Columbia, MO, USA.,Center for Botanical Interaction Studies, University of Missouri, Columbia, MO, USA.,Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA
| | - Grace Y Sun
- Interdisciplinary Neuroscience Program, University of Missouri, Columbia, MO, USA. .,Center for Translational Neuroscience, University of Missouri, Columbia, MO, USA. .,Center for Botanical Interaction Studies, University of Missouri, Columbia, MO, USA. .,Department of Biochemistry, University of Missouri, Columbia, MO, USA.
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14
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Du Plessis SS, Agarwal A, Halabi J, Tvrda E. Contemporary evidence on the physiological role of reactive oxygen species in human sperm function. J Assist Reprod Genet 2015; 32:509-20. [PMID: 25646893 PMCID: PMC4380893 DOI: 10.1007/s10815-014-0425-7] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 12/29/2014] [Indexed: 01/01/2023] Open
Abstract
Reactive oxygen species (ROS) play an important role in male fertility. Overproduction of reactive oxygen species (ROS) has been associated with a variety of male fertility complications, including leukocytospermia, varicocele and idiopathic infertility. The subsequent oxidative insult to spermatozoa can manifest as insufficient energy metabolism, lipid peroxidation and DNA damage, leading to loss of motility and viability. However, various studies have demonstrated that physiological amounts of ROS play important roles in the processes of spermatozoa maturation, capacitation, hyperactivation and acrosome reaction. It is therefore crucial to define and understand the delicate oxidative balance in male reproductive cells and tissues for a better understanding of both positive as well as negative impact of ROS production on the fertilizing ability. This review will discuss the specific physiological roles, mechanisms of action and effects that ROS have on the acquisition of structural integrity and physiological activity of spermatozoa.
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Affiliation(s)
- Stefan S. Du Plessis
- />Center for Reproductive Medicine, Cleveland Clinic, 10681 Carnegie Avenue, Mail Code X-11, Cleveland, OH 44195 USA
- />Division of Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, South Africa
| | - Ashok Agarwal
- />Center for Reproductive Medicine, Cleveland Clinic, 10681 Carnegie Avenue, Mail Code X-11, Cleveland, OH 44195 USA
| | - Jacques Halabi
- />Center for Reproductive Medicine, Cleveland Clinic, 10681 Carnegie Avenue, Mail Code X-11, Cleveland, OH 44195 USA
| | - Eva Tvrda
- />Center for Reproductive Medicine, Cleveland Clinic, 10681 Carnegie Avenue, Mail Code X-11, Cleveland, OH 44195 USA
- />Department of Animal Physiology, Slovak University of Agriculture, Nitra, Slovakia
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15
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Yun HM, Choi DY, Oh KW, Hong JT. PRDX6 Exacerbates Dopaminergic Neurodegeneration in a MPTP Mouse Model of Parkinson’s Disease. Mol Neurobiol 2014; 52:422-31. [DOI: 10.1007/s12035-014-8885-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 08/27/2014] [Indexed: 12/25/2022]
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16
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Yun HM, Jin P, Han JY, Lee MS, Han SB, Oh KW, Hong SH, Jung EY, Hong JT. Acceleration of the development of Alzheimer's disease in amyloid beta-infused peroxiredoxin 6 overexpression transgenic mice. Mol Neurobiol 2013; 48:941-51. [PMID: 23771816 DOI: 10.1007/s12035-013-8479-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 05/30/2013] [Indexed: 11/25/2022]
Abstract
The amyloid beta (Aβ) peptide in the brains of patients with Alzheimer's disease (AD) is cytotoxic to neurons and has a central role in the pathogenesis of the disease. Peroxiredoxin 6 (Prdx6) is an antioxidant protein and could act as a cytoprotective protein. However, the role of Prdx6 in neurodegenerative disease has not been studied. Thus, the roles and action mechanisms in the development of AD were examined. Aβ1-42-induced memory impairment in Prdx6 transgenic mice was worse than C57BL/6 mice, and the expression of amyloid precursor protein cleavage, C99, β-site APP-cleaving enzyme 1, inducible nitric oxide synthase, and cyclooxygenase-2 was greatly increased. In addition, the astrocytes and microglia cells of Aβ-infused Prdx6 transgenic mice were more activated, and Aβ also significantly increased lipid peroxidation and protein carbonyl levels, but decreased glutathione levels. Furthermore, we found that translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) to the nucleus was increased in Aβ-infused Prdx6 transgenic mice. These results suggest that the overexpression of Prdx6 could accelerate the development of AD through increased amyloidogenesis through independent PLA2 activation and Nrf2 transcription.
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Affiliation(s)
- Hyung-Mun Yun
- College of Pharmacy and Medical Research Center, Chungbuk National University, 12 Gaesin-dong, Heungduk-gu, Cheongju, Chungbuk, 361-763, South Korea
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17
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Mazerik JN, Mikkilineni H, Kuppusamy VA, Steinhour E, Peltz A, Marsh CB, Kuppusamy P, Parinandi NL. Mercury activates phospholipase a(2) and induces formation of arachidonic Acid metabolites in vascular endothelial cells. Toxicol Mech Methods 2012; 17:541-57. [PMID: 20020881 DOI: 10.1080/15376510701380505] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
ABSTRACT Currently, mercury has been identified as a risk factor in cardiovascular diseases among humans. Here, we tested our hypothesis that mercury modulates the activity of the vascular endothelial cell (EC) lipid signaling enzyme phospholipase A(2) (PLA(2)), which is an important player in the EC barrier functions. Monolayers of bovine pulmonary artery ECs (BPAECs) in culture, following labeling of membrane phospholipids with [(3)H]arachidonic acid (AA), were exposed to the inorganic form of mercury, mercury chloride, and the release of free AA (index of PLA(2) activity) and formation of AA metabolites were determined by liquid scintillation counting and enzyme immunoassay, respectively. Mercury chloride significantly activated PLA(2) in BPAECs in a dose-dependent (0 to 50 muM) and time-dependent (0 to 120 min) fashion. Metal chelators significantly attenuated mercury-induced PLA(2) activation, suggesting that cellular mercury-ligand interaction is required for the enzyme activation and that chelators are suitable blockers for mercury-induced PLA(2) activation in ECs. Sulfhydryl (thiol-protective) agents, calcium chelating agents, and cPLA(2)-specific inhibitor also significantly attenuated the mercury-induced PLA(2), suggesting the role of thiol and calcium in the activation of cPLA(2) in BPAECs. Significant formation of AA metabolites, including the release of total prostaglandins, thromboxane B(2), and 8-isoprostane, were observed in BPAECs following their exposure to mercury chloride. Mercury chloride induced cytotoxicity as observed by the altered cell morphology and enhanced trypan blue uptake, which was attenuated by the cPLA(2) inhibitor AACOCF(3). The results of this study revealed that inorganic mercury-induced PLA(2) activation through the thiol and calcium signaling and the formation of bioactive AA metabolites further demonstrated the association of PLA(2) with the cytotoxicity of mercury in ECs. Overall, the results of the current study underscore the importance of PLA(2) signaling in mercury-induced endothelial dysfunctions.
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Affiliation(s)
- Jessica N Mazerik
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, United States
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18
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Maintenance of synaptic stability requires calcium-independent phospholipase A₂ activity. Neural Plast 2012; 2012:569149. [PMID: 22685677 PMCID: PMC3364014 DOI: 10.1155/2012/569149] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 02/03/2012] [Accepted: 02/07/2012] [Indexed: 12/31/2022] Open
Abstract
Phospholipases A₂ (PLA₂s) represent one of the largest groups of lipid-modifying enzymes. Over the years, significant advances have been made in understanding their potential physiological and pathological functions. Depending on their calcium requirement for activation, PLA₂s are classified into calcium dependent and independent. This paper mainly focuses on brain calcium-independent PLA₂ (iPLA₂) and on the mechanisms by which they influence neuronal function and regulate synaptic plasticity. Particular attention will be given to the iPLA₂γ isoform and its role in the regulation of synaptic glutamate receptors. In particular, the paper discusses the possibility that brain iPLA₂γ deficiencies could destabilise normal synaptic operation and might contribute to the aetiology of some brain disorders. In this line, the paper presents new data indicating that iPLA₂γ deficiencies accentuate AMPA receptor destabilization and tau phosphorylation, which suggests that this iPLA₂ isoform should be considered as a potential target for the treatment of Tau-related disorders.
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19
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Eicosanoid Signaling and Vascular Dysfunction: Methylmercury-Induced Phospholipase D Activation in Vascular Endothelial Cells. Cell Biochem Biophys 2011; 67:317-29. [DOI: 10.1007/s12013-011-9304-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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20
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Shibata N, Kato Y, Inose Y, Hiroi A, Yamamoto T, Morikawa S, Sawada M, Kobayashi M. 4-Hydroxy-2-nonenal upregulates and phosphorylates cytosolic phospholipase A(2) in cultured Ra2 microglial cells via MAPK pathways. Neuropathology 2011; 31:122-8. [PMID: 20667012 DOI: 10.1111/j.1440-1789.2010.01139.x] [Citation(s) in RCA: 203] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Several studies have suggested the involvement of neuroinflammation in the pathomechanism of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). We recently demonstrated increased levels of protein-bound 4-hydroxy-2-nonenal (HNE) as a highly reactive lipid peroxidation product and cytosolic phospholipase A(2) (cPLA(2)) as a proinflammatory enzyme in glial cells as well as motor neurons in the spinal cord of sporadic ALS patients. However, a link between HNE and cPLA(2) in ALS remains to be determined. To address this issue, we investigated effects of HNE stimulation on the state of cPLA(2) expression in cultured microglial cell line (Ra2). Exposure of Ra2 cells to HNE significantly increased expression levels of cPLA(2) and its activated form phosphorylated at amino acid residue S(505) (p-cPLA(2)) on immunoblots. Pretreatment of Ra2 cells with the antioxidant N-acetylcysteine, the extracellular signal-regulated kinase (ERK) inhibitor PD98059 or the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 prevented the HNE-induced increased expression of cPLA(2) and p-cPLA(2). Immunocytochemical analysis revealed that staining for p-cPLA(2) in Ra2 cells was localized in the cytoplasm and more intense in the HNE-stimulated group than in the vehicle group. The present results provide in vitro evidence that HNE upregulates and phosphorylates cPLA(2) in microglia via the ERK and p38 MAPK pathways.
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Affiliation(s)
- Noriyuki Shibata
- Department of Pathology, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan.
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21
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Schaeffer EL, da Silva ER, Novaes BDA, Skaf HD, Gattaz WF. Differential roles of phospholipases A2 in neuronal death and neurogenesis: implications for Alzheimer disease. Prog Neuropsychopharmacol Biol Psychiatry 2010; 34:1381-9. [PMID: 20804810 DOI: 10.1016/j.pnpbp.2010.08.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 08/04/2010] [Accepted: 08/21/2010] [Indexed: 01/06/2023]
Abstract
The involvement of phospholipase A(2) (PLA(2)) in Alzheimer disease (AD) was first investigated nearly 15 years ago. Over the years, several PLA(2) isoforms have been detected in brain tissue: calcium-dependent secreted PLA(2) or sPLA(2) (IIA, IIC, IIE, V, X, and XII), calcium-dependent cytosolic PLA(2) or cPLA(2) (IVA, IVB, and IVC), and calcium-independent PLA(2) or iPLA(2) (VIA and VIB). Additionally, numerous in vivo and in vitro studies have suggested the role of different brain PLA(2) in both physiological and pathological events. This review aimed to summarize the findings in the literature relating the different brain PLA(2) isoforms with alterations found in AD, such as neuronal cell death and impaired neurogenesis process. The review showed that sPLA(2)-IIA, sPLA(2)-V and cPLA(2)-IVA are involved in neuronal death, whereas sPLA(2)-III and sPLA(2)-X are related to the process of neurogenesis, and that the cPLA(2) and iPLA(2) groups can be involved in both neuronal death and neurogenesis. In AD, there are reports of reduced activity of the cPLA(2) and iPLA(2) groups and increased expression of sPLA(2)-IIA and cPLA(2)-IVA. The findings suggest that the inhibition of cPLA(2) and iPLA(2) isoforms (yet to be determined) might contribute to impaired neurogenesis, whereas stimulation of sPLA(2)-IIA and cPLA(2)-IVA might contribute to neurodegeneration in AD.
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Affiliation(s)
- Evelin L Schaeffer
- Laboratory of Neuroscience (LIM-27), Department and Institute of Psychiatry, Faculty of Medicine, University of Sao Paulo, Rua Dr. Ovídio Pires de Campos 785, 05403-010, Sao Paulo, SP, Brazil.
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22
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Galindo MF, Ikuta I, Zhu X, Casadesus G, Jordán J. Mitochondrial biology in Alzheimer's disease pathogenesis. J Neurochem 2010; 114:933-45. [PMID: 20492350 DOI: 10.1111/j.1471-4159.2010.06814.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Despite the increasing knowledge of Alzheimer's disease (AD) management with novel pharmacologic agents, most of them are only transiently fixing symptomatic pathology. Currently there is rapid growth in the field of neuroprotective pharmacology and increasing focus on the involvement of mitochondria in this devastating disease. This review is directed at understanding the role of mitochondria-mediated pathways in AD and integrating basic biology of the mitochondria with knowledge of possible pharmacologic targets for AD treatment in an attempt to elucidate novel mitochondria-driven therapeutic interventions useful to both clinical and basic research.
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Affiliation(s)
- María F Galindo
- Unidad de Neuropsicofarmacología Translacional, Complejo Hospitalario Universitario de Albacete, Albacete, Spain
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23
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Sun GY, Shelat PB, Jensen MB, He Y, Sun AY, Simonyi A. Phospholipases A2 and inflammatory responses in the central nervous system. Neuromolecular Med 2009; 12:133-48. [PMID: 19855947 DOI: 10.1007/s12017-009-8092-z] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Accepted: 09/25/2009] [Indexed: 12/21/2022]
Abstract
Phospholipases A2 (PLA2s) belong to a superfamily of enzymes responsible for hydrolyzing the sn-2 fatty acids of membrane phospholipids. These enzymes are known to play multiple roles for maintenance of membrane phospholipid homeostasis and for production of a variety of lipid mediators. Over 20 different types of PLA2s are present in the mammalian cells, and in snake and bee venom. Despite their common function in hydrolyzing fatty acids of phospholipids, they are diversely encoded by a number of genes and express proteins that are regulated by different mechanisms. Recent studies have focused on the group IV calcium-dependent cytosolic cPLA2, the group VI calcium-independent iPLA2, and the group II small molecule secretory sPLA2. In the central nervous system (CNS), these PLA2s are distributed among neurons and glial cells. Although the physiological role of these PLA2s in regulating neural cell function has not yet been clearly elucidated, there is increasing evidence for their involvement in receptor signaling and transcriptional pathways that link oxidative events to inflammatory responses that underline many neurodegenerative diseases. Recent studies also reveal an important role of cPLA2 in modulating neuronal excitatory functions, sPLA2 in the inflammatory responses, and iPLA2 with childhood neurologic disorders associated with brain iron accumulation. The goal for this review is to better understand the structure and function of these PLA2s and to highlight specific types of PLA2s and their cross-talk mechanisms in these inflammatory responses under physiological and pathological conditions in the CNS.
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Affiliation(s)
- Grace Y Sun
- Department of Biochemistry, University of Missouri, 117 Schweitzer Hall, Columbia, MO 65211, USA.
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24
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NAD(P)H oxidase-mediated reactive oxygen species production alters astrocyte membrane molecular order via phospholipase A2. Biochem J 2009; 421:201-10. [PMID: 19392662 DOI: 10.1042/bj20090356] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
ROS (reactive oxygen species) overproduction is an important underlying factor for the activation of astrocytes in various neuropathological conditions. In the present study, we examined ROS production in astrocytes and downstream effects leading to changes in the signalling cascade, morphology and membrane dynamics using menadione, a redox-active compound capable of inducing intracellular ROS. NAD(P)H oxidase-mediated menadione-induced ROS production, which then stimulated phosphorylation of p38 MAPK (mitogen-activated protein kinase) and ERK1/2 (extracellular-signal-regulated kinase 1/2), and increased actin polymerization and cytoskeletal protrusions. We also showed that astrocyte plasma membranes became more molecularly ordered under oxidative stress, which was abrogated by down-regulating cPLA2 (cytosolic phospholipase A2) either with a pharmacological inhibitor or by RNA interference. In addition, mild disruption of F-actin with cytochalasin D suppressed menadione-enhanced phosphorylation of cPLA2 and membrane alterations. Taken together, these results suggest an important role for ROS derived from NAD(P)H oxidase in activation of astrocytes to elicit biochemical, morphological and biophysical changes reminiscent of reactive astrocytes in pathological conditions.
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25
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Rosa AO, Rapoport SI. Intracellular- and extracellular-derived Ca(2+) influence phospholipase A(2)-mediated fatty acid release from brain phospholipids. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:697-705. [PMID: 19327408 DOI: 10.1016/j.bbalip.2009.03.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 03/01/2009] [Accepted: 03/11/2009] [Indexed: 02/01/2023]
Abstract
Docosahexaenoic acid (DHA) and arachidonic acid (AA) are found in high concentrations in brain cell membranes and are important for brain function and structure. Studies suggest that AA and DHA are hydrolyzed selectively from the sn-2 position of synaptic membrane phospholipids by Ca(2+)-dependent cytosolic phospholipase A(2) (cPLA(2)) and Ca(2+)-independent phospholipase A(2) (iPLA(2)), respectively, resulting in increased levels of the unesterified fatty acids and lysophospholipids. Cell studies also suggest that AA and DHA release depend on increased concentrations of Ca(2+), even though iPLA(2) has been thought to be Ca(2+)-independent. The source of Ca(2+) for activation of cPLA(2) is largely extracellular, whereas Ca(2+) released from the endoplasmic reticulum can activate iPLA(2) by a number of mechanisms. This review focuses on the role of Ca(2+) in modulating cPLA(2) and iPLA(2) activities in different conditions. Furthermore, a model is suggested in which neurotransmitters regulate the activity of these enzymes and thus the balanced and localized release of AA and DHA from phospholipid in the brain, depending on the primary source of the Ca(2+) signal.
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Affiliation(s)
- Angelo O Rosa
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
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26
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Xu ZY, Liu HD, Lau LT, Yingge Z, Zhao R, Tong GL, Chan PH, Yu ACH. Responses of astrocyte to simultaneous glutamate and arachidonic acid treatment. Neurochem Int 2009; 55:143-50. [DOI: 10.1016/j.neuint.2009.02.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 02/17/2009] [Accepted: 02/25/2009] [Indexed: 10/21/2022]
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González A, Salido GM. Ethanol alters the physiology of neuron-glia communication. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2009; 88:167-98. [PMID: 19897078 DOI: 10.1016/s0074-7742(09)88007-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In the central nervous system (CNS), both neurones and astrocytes play crucial roles. On a cellular level, brain activity involves continuous interactions within complex cellular circuits established between neural cells and glia. Although it was initially considered that neurones were the major cell type in cerebral function, nowadays astrocytes are considered to contribute to cerebral function too. Astrocytes support normal neuronal activity, including synaptic function, by regulating the extracellular environment with respect to ions and neurotransmitters. There is a plethora of noxious agents which can lead to the development of alterations in organs and functional systems, and that will end in a chronic prognosis. Among the potentially harmful external agents we can find ethanol consumption, whose consequences have been recognized as a major public health concern. Deregulation of cell cycle has devastating effects on the integrity of cells, and has been closely associated with the development of pathologies which can lead to dysfunction and cell death. An alteration of normal neuronal-glial physiology could represent the basis of neurodegenerative processes. In this review we will pay attention on to the recent findings in astrocyte function and their role toward neurons under ethanol consumption.
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Affiliation(s)
- Antonio González
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10071, Cáceres, Spain
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Steinhour E, Sherwani SI, Mazerik JN, Ciapala V, Butler EO, Cruff JP, Magalang U, Parthasarathy S, Sen CK, Marsh CB, Kuppusamy P, Parinandi NL. Redox-active antioxidant modulation of lipid signaling in vascular endothelial cells: vitamin C induces activation of phospholipase D through phospholipase A2, lipoxygenase, and cyclooxygenase. Mol Cell Biochem 2008; 315:97-112. [PMID: 18496733 PMCID: PMC5067108 DOI: 10.1007/s11010-008-9793-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Accepted: 05/06/2008] [Indexed: 10/22/2022]
Abstract
We have earlier reported that the redox-active antioxidant, vitamin C (ascorbic acid), activates the lipid signaling enzyme, phospholipase D (PLD), at pharmacological doses (mM) in the bovine lung microvascular endothelial cells (BLMVECs). However, the activation of phospholipase A(2) (PLA(2)), another signaling phospholipase, and the modulation of PLD activation by PLA(2) in the ECs treated with vitamin C at pharmacological doses have not been reported to date. Therefore, this study aimed at the regulation of PLD activation by PLA(2) in the cultured BLMVECs exposed to vitamin C at pharmacological concentrations. The results revealed that vitamin C (3-10 mM) significantly activated PLA(2) starting at 30 min; however, the activation of PLD resulted only at 120 min of treatment of cells under identical conditions. Further studies were conducted utilizing specific pharmacological agents to understand the mechanism(s) of activation of PLA(2) and PLD in BLMVECs treated with vitamin C (5 mM) for 120 min. Antioxidants, calcium chelators, iron chelators, and PLA(2) inhibitors offered attenuation of the vitamin C-induced activation of both PLA(2) and PLD in the cells. Vitamin C was also observed to significantly induce the formation and release of the cyclooxygenase (COX)- and lipoxygenase (LOX)-catalyzed arachidonic acid (AA) metabolites and to activate the AA LOX in BLMVECs. The inhibitors of PLA(2), COX, and LOX were observed to effectively and significantly attenuate the vitamin C-induced PLD activation in BLMVECs. For the first time, the results of the present study revealed that the vitamin C-induced activation of PLD in vascular ECs was regulated by the upstream activation of PLA(2), COX, and LOX through the formation of AA metabolites involving oxidative stress, calcium, and iron.
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Affiliation(s)
- Emily Steinhour
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Shariq I. Sherwani
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Jessica N. Mazerik
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Valorie Ciapala
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Elizabeth O’Connor Butler
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Jason P. Cruff
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Ulysses Magalang
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Sampath Parthasarathy
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Chandan K. Sen
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Clay B. Marsh
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Periannan Kuppusamy
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Narasimham L. Parinandi
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA. Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, The Ohio State University, 473 W. 12th Avenue, Columbus, OH 43210, USA
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Kurusu S, Matsui K, Watanabe T, Tsunou T, Kawaminami M. The cytotoxic effect of bromoenol lactone, a calcium-independent phospholipase A2 inhibitor, on rat cortical neurons in culture. Cell Mol Neurobiol 2008; 28:1109-18. [PMID: 18528752 DOI: 10.1007/s10571-008-9287-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Accepted: 05/20/2008] [Indexed: 12/30/2022]
Abstract
This study characterized the phospholipase A(2) (PLA(2)) activity in cerebral cortex of fetal rat brain and investigated effects of chemical inhibition of Ca(2+)-independent PLA(2) (iPLA(2)) on neurite outgrowth and cell development of cortical neurons in vitro. The PLA(2) activity in fetal brain was insensitive to a Ca(2+)-chelator EGTA and was significantly impaired by an iPLA(2) inhibitor, bromoenol lactone (BEL). Following treatment with BEL, cortical neurons showed acute loss of neurites and impaired cell body, which were clearly dose- and time-dependent. Nuclear staining revealed nuclear regression (shrinkage), but not fragmentation, in BEL-treated cells. The cytotoxic effect of BEL was additive with arachidonic acid (AA) and AA alone also induced neurite demise. BEL treatment resulted in increased production of prostaglandin E(2). Overall data suggest that iPLA(2), a primary PLA(2) isoform in cerebral cortex, displays a housekeeping role in development and neurite outgrowth in cortical neurons in vitro probably via maintaining phospholipid membrane remodeling rather than generating free fatty acids and lysophospholipids.
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Affiliation(s)
- Shiro Kurusu
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine, Towada, Aomori 034-8628, Japan.
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Peterson B, Stovall K, Monian P, Franklin JL, Cummings BS. Alterations in phospholipid and fatty acid lipid profiles in primary neocortical cells during oxidant-induced cell injury. Chem Biol Interact 2008; 174:163-76. [PMID: 18602625 DOI: 10.1016/j.cbi.2008.05.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Revised: 05/19/2008] [Accepted: 05/22/2008] [Indexed: 10/22/2022]
Abstract
Specific phospholipids and fatty acids altered during oxidant-induced neuronal cell injury were determined using electrospray ionization mass spectrometry (ESI-MS) and ion trapping. The oxidants hydrogen peroxide (H(2)O(2), 0-1000 microM) and tert-butylhydroperoxide (TBHP, 0-400 microM) induced time- and concentration-dependent increases in reactive oxygen species in primary cultures of mouse neocortical cells as determined by 2',7'-dichlorofluorescein diacetate staining and thiobarbituric acid formation. ESI-MS analysis of 26 m/z values, representing 42 different phospholipids, demonstrated that H(2)O(2) and TBHP increased the abundance of phospholipids containing polyunsaturated fatty acids, but had minimal affect on those containing mono- or di-unsaturated fatty acids. These increases correlated to time-dependent increase in 16:1-20:4, 16:0-20:4, 18:1-20:4 and 18:0-20:4 phosphatidylcholine. Oxidant exposure also increased mystric (14:0), palmitic (16:0), and stearic (18:0) acid twofold, oleic acid (18:1) two- to threefold, and arachidonic acid (20:4) fourfold, compared to controls. Increases in arachidonic acid levels occurred prior to increases in the phospholipids, but after increases in ROS, and correlated to increases in oxidized arachidonic acid species, specifically [20:4-OOH]-H(2)O-, 20:4-OH-, and Tri-OH-20:4-arachidonic acid. Treatment of cells with methyl arachidonyl flourophosphonate an inhibitor of Group IV and VI PLA(2), decreased oxidant-induced arachidonic acid release, while bromoenol lactone, an inhibitor of Group VI PLA(2), did not. Collectively, these data identify phospholipids and fatty acids altered during oxidant treatment of neurons and suggest differential roles for Group IV and VI PLA(2) in oxidant-induced neural cell injury.
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Affiliation(s)
- Brianna Peterson
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, GA 30602-2352, United States
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Umannová L, Neča J, Andrysík Z, Vondráček J, Upham B, Trosko J, Hofmanová J, Kozubík A, Machala M. Non-dioxin-like polychlorinated biphenyls induce a release of arachidonic acid in liver epithelial cells: a partial role of cytosolic phospholipase A(2) and extracellular signal-regulated kinases 1/2 signalling. Toxicology 2008; 247:55-60. [PMID: 18367304 PMCID: PMC2577785 DOI: 10.1016/j.tox.2008.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 02/06/2008] [Accepted: 02/06/2008] [Indexed: 01/07/2023]
Abstract
Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) have been shown to act as tumor promoters in liver; however, the exact mechanisms of their action are still only partially understood. One of the interesting effects of NDL-PCBs is the acute inhibition of gap junctional intercellular communication (GJIC), an effect, which has been often found to be associated with tumor promotion. As previous studies have suggested that NDL-PCB-induced disruption of lipid signalling pathways might correspond with GJIC inhibition, we investigated effects of PCBs on the release of arachidonic acid (AA) in the rat liver epithelial WB-F344 cell line, a well-established model of liver progenitor cells. We found that both 2,2',4,4'-tetrachlorobiphenyl (PCB 47) and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153), but not the dioxin-like, non-ortho-substituted, 3,3',4,4',5-pentachlorobiphenyl (PCB 126), induce a massive release of AA. The AA release, induced by PCB 153, was partially inhibited by extracellular signal-regulated kinases 1/2 (ERK1/2) signalling inhibitor, U0126, and by cytosolic phospholipase A(2) (cPLA(2)) inhibitor, AACOCF(3). Although PCB 153 induced both ERK1/2 and p38 activation, the specific p38 kinase inhibitor, SB203580, had no effect on AA release. Inhibitors of other phospholipases, including phosphatidylcholine-specific phospholipase C or phosphatidylinositol-specific phospholipase C, were also without effect. Taken together, our findings suggest that the AA release, induced by non-dioxin-like PCBs in liver progenitor cell line, is partially mediated by cytosolic PLA(2) and regulated by ERK1/2 kinases. Our results suggest that more attention should be paid to cell signalling pathways regulated by AA or eicosanoids after PCB exposure, which might be involved in their toxic effects.
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Affiliation(s)
- L. Umannová
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
- Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - J. Neča
- Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - Z. Andrysík
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
| | - J. Vondráček
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
- Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - B.L. Upham
- National Food Safety & Toxicology Center, Michigan State University, East Lansing MI 48824, USA
| | - J.E. Trosko
- National Food Safety & Toxicology Center, Michigan State University, East Lansing MI 48824, USA
| | - J. Hofmanová
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
- Institute of Experimental Biology, Faculty of Science, Masaryk University, 611 37 Brno, Czech Republic
| | - A. Kozubík
- Department of Cytokinetics, Institute of Biophysics ASCR, 612 65 Brno, Czech Republic
- Institute of Experimental Biology, Faculty of Science, Masaryk University, 611 37 Brno, Czech Republic
| | - M. Machala
- Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
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Cholinergic and glutamatergic alterations beginning at the early stages of Alzheimer disease: participation of the phospholipase A2 enzyme. Psychopharmacology (Berl) 2008; 198:1-27. [PMID: 18392810 DOI: 10.1007/s00213-008-1092-0] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Accepted: 01/28/2008] [Indexed: 12/14/2022]
Abstract
RATIONALE Alzheimer disease (AD), a progressive neurodegenerative disorder, is the leading cause of dementia in the elderly. A combination of cholinergic and glutamatergic dysfunction appears to underlie the symptomatology of AD, and thus, treatment strategies should address impairments in both systems. Evidence suggests the involvement of phospholipase A(2) (PLA(2)) enzyme in memory impairment and neurodegeneration in AD via actions on both cholinergic and glutamatergic systems. OBJECTIVES To review cholinergic and glutamatergic alterations underlying cognitive impairment and neuropathology in AD and attempt to link PLA(2) with such alterations. METHODS Medline databases were searched (no date restrictions) for published articles with links among the terms Alzheimer disease (mild, moderate, severe), mild cognitive impairment, choline acetyltransferase, acetylcholinesterase, NGF, NGF receptor, muscarinic receptor, nicotinic receptor, NMDA, AMPA, metabotropic glutamate receptor, atrophy, glucose metabolism, phospholipid metabolism, sphingolipid, membrane fluidity, phospholipase A(2), arachidonic acid, attention, memory, long-term potentiation, beta-amyloid, tau, inflammation, and reactive species. Reference lists of the identified articles were checked to identify additional studies of interest. RESULTS Overall, results suggest the hypothesis that persistent inhibition of cPLA(2) and iPLA(2) isoforms at early stages of AD may play a central role in memory deficits and beta-amyloid production through down-regulation of cholinergic and glutamate receptors. As the disease progresses, beta-amyloid induced up-regulation of cPLA(2) and sPLA(2) isoforms may play critical roles in inflammation and oxidative stress, thus participating in the neurodegenerative process. CONCLUSION Activation and inhibition of specific PLA(2) isoforms at different stages of AD could be of therapeutic importance and delay cognitive dysfunction and neurodegeneration.
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Mazerik JN, Hagele T, Sherwani S, Ciapala V, Butler S, Kuppusamy ML, Hunter M, Kuppusamy P, Marsh CB, Parinandi NL. Phospholipase A2 activation regulates cytotoxicity of methylmercury in vascular endothelial cells. Int J Toxicol 2008; 26:553-69. [PMID: 18066971 DOI: 10.1080/10915810701707759] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Mercury has been identified as a risk factor for cardiovascular disease among humans. Through diet, mainly fish consumption, humans are exposed to methylmercury, the biomethylated organic form of environmental mercury. As the endothelium is an important player in homeostasis of the cardiovascular system, here, the authors tested their hypothesis that methylmercury activates the lipid signaling enzyme phospholipase A(2) (PLA(2)) in vascular endothelial cells (ECs), causing upstream regulation of cytotoxicity. To test this hypothesis, the authors used bovine pulmonary artery ECs (BPAECs) cultured in monolayers, following labeling of their membrane phospholipids with [(3)H]arachidonic acid (AA). The cells were exposed to methylmercury chloride (MMC) and then the release of free AA (index of PLA(2) activity) and lactate dehydrogenase (LDH; index of cytotoxicity) were determined by liquid scintillation counting and spectrophotometry, respectively. MMC significantly activated PLA(2) in a dose-dependent (5 to 15 microM) and time-dependent (0 to 60 min) fashion. Sulfhydryl (thiol-protective) agents, calcium chelators, antioxidants, and PLA(2)-specific inhibitors attenuated the MMC-induced PLA(2) activation, suggesting the role of thiols, reactive oxygen species (ROS), and calcium in the activation of PLA(2) in BPAECs. MMC also induced the loss of thiols and increase of lipid peroxidation in BPAECs. MMC induced cytotoxicity in BPAECs as observed by the altered cell morphology and LDH leak, which was significantly attenuated by PLA(2) inhibitors. This study established that PLA(2) activation through thiols, calcium, and oxidative stress was associated with the cytotoxicity of MMC in BPAECs, drawing attention to the involvement of PLA(2) signaling in the methylmercury-induced vascular endothelial dysfunctions.
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Affiliation(s)
- Jessica N Mazerik
- Lipid Signaling and Lipidomics Laboratory, Division of Pulmonary, Allergy, Critical Care, The Ohio State University College of Medicine, Columbus, Ohio, USA
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González A, Pariente JA, Salido GM. Ethanol stimulates ROS generation by mitochondria through Ca2+ mobilization and increases GFAP content in rat hippocampal astrocytes. Brain Res 2007; 1178:28-37. [PMID: 17888892 DOI: 10.1016/j.brainres.2007.08.040] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 06/29/2007] [Accepted: 08/12/2007] [Indexed: 01/04/2023]
Abstract
We have employed rat hippocampal astrocytes in culture to investigate the effect of ethanol on reactive oxygen species (ROS) production as well as its effect on [Ca2+]c and GFAP expression. Cells were loaded with the fluorescent probes fura-2 and H2DCFDA for the determination of changes in [Ca2+]c and ROS production respectively, employing spectrofluorimetry. GFAP content was determined by immunocytochemistry and confocal scanning microscopy. Our results show ROS production in response to 50 mM ethanol, that was reduced in Ca2+-free medium (containing 0.5 mM EGTA) and in the presence of the intracellular Ca2+ chelator BAPTA (10 microM). The effect of ethanol on ROS production was significantly reduced in the presence of the alcohol dehydrogenase inhibitor 4-methylpyrazole (1 mM), and the antioxidants resveratrol (100 microM) or catalase (300 U/ml). Preincubation of astrocytes in the presence of 10 microM antimycin plus 10 microM oligomycin to inhibit mitochondria completely blocked ethanol-evoked ROS production. In addition, ethanol led to a sustained increase in [Ca2+]c that reached a constant level over the prestimulation values. Finally, incubation of astrocytes in the presence of ethanol increased the content of GFAP that was significantly reduced in the absence of extracellular Ca2+ and by resveratrol and catalase pretreatment. The data obtained in the present study suggest that astrocytes are able to metabolize ethanol, which induces two effects on intracellular homeostasis: an immediate response (Ca2+ release and ROS generation) and later changes involving GFAP expression. Both effects may underline various signaling pathways which are important for cell proliferation, differentiation and function.
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Affiliation(s)
- Antonio González
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, Cáceres, Spain.
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Sun GY, Horrocks LA, Farooqui AA. The roles of NADPH oxidase and phospholipases A2 in oxidative and inflammatory responses in neurodegenerative diseases. J Neurochem 2007; 103:1-16. [PMID: 17561938 DOI: 10.1111/j.1471-4159.2007.04670.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Reactive oxygen species (ROS) are produced in mammalian cells through enzymic and non-enzymic mechanisms. Although some ROS production pathways are needed for specific physiological functions, excessive production is detrimental and is regarded as the basis of numerous neurodegenerative diseases. Among enzymes producing superoxide anions, NADPH oxidase is widespread in mammalian cells and is an important source of ROS in mediating physiological and pathological processes in the cardiovascular and the CNS. ROS production is linked to the alteration of intracellular calcium homeostasis, activation of Ca(2+)-dependent enzymes, alteration of cytoskeletal proteins, and degradation of membrane glycerophospholipids. There is evolving evidence that ROS produced by NADPH oxidase regulate neuronal functions and degrade membrane phospholipids through activation of phospholipases A(2) (PLA(2)). This review is intended to cover recent studies describing ROS generation from NADPH oxidase in the CNS and its downstream activation of PLA(2), namely, the group IV cytosolic cPLA(2) and the group II secretory sPLA(2). A major focus is to elaborate the dual role of NADPH oxidase and PLA(2) in mediating the oxidative and inflammatory responses in neurodegenerative diseases, including cerebral ischemia and Alzheimer's disease. Elucidation of the signaling pathways linking NADPH oxidase with the multiple forms of PLA(2) will be important in understanding the oxidative and degradative mechanisms that underline neuronal damage and glial activation and will facilitate development of therapeutic intervention for prevention and treatment of these and other neurodegenerative diseases.
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Affiliation(s)
- Grace Y Sun
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA.
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Scherz-Shouval R, Shvets E, Fass E, Shorer H, Gil L, Elazar Z. Reactive oxygen species are essential for autophagy and specifically regulate the activity of Atg4. EMBO J 2007; 26:1749-60. [PMID: 17347651 PMCID: PMC1847657 DOI: 10.1038/sj.emboj.7601623] [Citation(s) in RCA: 1576] [Impact Index Per Article: 92.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Accepted: 01/24/2007] [Indexed: 02/06/2023] Open
Abstract
Autophagy is a major catabolic pathway by which eukaryotic cells degrade and recycle macromolecules and organelles. This pathway is activated under environmental stress conditions, during development and in various pathological situations. In this study, we describe the role of reactive oxygen species (ROS) as signaling molecules in starvation-induced autophagy. We show that starvation stimulates formation of ROS, specifically H(2)O(2). These oxidative conditions are essential for autophagy, as treatment with antioxidative agents abolished the formation of autophagosomes and the consequent degradation of proteins. Furthermore, we identify the cysteine protease HsAtg4 as a direct target for oxidation by H(2)O(2), and specify a cysteine residue located near the HsAtg4 catalytic site as a critical for this regulation. Expression of this regulatory mutant prevented the formation of autophagosomes in cells, thus providing a molecular mechanism for redox regulation of the autophagic process.
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Affiliation(s)
- Ruth Scherz-Shouval
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Elena Shvets
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Ephraim Fass
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Hagai Shorer
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Lidor Gil
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Zvulun Elazar
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, 76100 Israel. Tel.: +972 8 9343682; Fax: +972 8 9344112; E-mail:
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Song C, Li X, Kang Z, Kadotomi Y. Omega-3 fatty acid ethyl-eicosapentaenoate attenuates IL-1beta-induced changes in dopamine and metabolites in the shell of the nucleus accumbens: involved with PLA2 activity and corticosterone secretion. Neuropsychopharmacology 2007; 32:736-44. [PMID: 16794572 DOI: 10.1038/sj.npp.1301117] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Previously, we have reported that interleukin-1 beta (IL-1) induces changes in dopaminergic (DA) and serotonergic systems in the core of the [corrected] nucleus accumbens (NAc). We have also demonstrated that n-3 fatty acid ethyl-eicosapentaenoate (EPA) can significantly reduce stress and anxiety-like behaviors, corticosterone concentrations [corrected] and peripheral inflammatory response induced by IL-1 administration. Compared to the core, the shell is involved more in emotion, stress and psychiatric diseases. However, the relationship between inflammation and the functions of DA system in the shell has not been studied. Since phospholipase (PL) A2 is a key enzyme in the [corrected] arachidonic acid-eicosanoids-prostaglandin [corrected] (PG)E2 pathway, and the change in NAc DA [corrected] system has been associated with glucocorticoid stimulation; [corrected] therefore, the hypotheses of this study are (1) that IL-1 induced changes in DA neurotransmission in the shell may be through PLA2-PGE2-corticosterone pathway; (2) EPA may attenuate IL-1 effects via inhibiting PLA2 activities, which blocks PGE2 stimulation of corticosterone. Using an in vivo microdialysis method, the present study showed that IL-1 administration significantly increased extracellular levels of DA, and its metabolites 3,4-dihydroxyphenylacetic acid, [corrected] and homovanillic acid [corrected] in the shell of the NAc. IL-1 also increased blood concentration of corticosterone and PGE2, and increased the activities of cytosolic and secretory [corrected] PLA2. IL-1-induced changes were significantly attenuated by EPA treatment. Furthermore, glucocorticoid [corrected] receptor antagonist mifepristone (RU486) pretreatment significantly blocked IL-1-induced changes in DA and metabolites. Quinacrine, [corrected] a PLA2 antagonist significantly blocked IL-1-induced [corrected] increase in PGE2 and corticosterone concentrations. These results demonstrated the hypotheses that IL-1 effects may be via PLA2-PGE2-corticosterone pathway and EPA attenuated IL-1 effects may be through the suppression of PLA2 expression, which then reduced PGE2 synthesis and corticosterone secretion.
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Affiliation(s)
- Cai Song
- Department of Biomedical Sciences, AVC, University of Prince Edward Island, Charlottetown, PE, Canada.
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Obajimi O, Black KD, Glen I, Ross BM. Antioxidant modulation of oxidant-stimulated uptake and release of arachidonic acid in eicosapentaenoic acid-supplemented human lymphoma U937 cells. Prostaglandins Leukot Essent Fatty Acids 2007; 76:65-71. [PMID: 17198751 DOI: 10.1016/j.plefa.2006.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 09/14/2006] [Accepted: 11/07/2006] [Indexed: 10/23/2022]
Abstract
Omega-3 polyunsaturated fatty acids (PUFA) are increasingly finding use as treatments for a variety of medical conditions. PUFA supplementation can, however, result in increased oxidative stress causing elevated turnover rate of membrane phospholipids, impairment of membrane integrity and increased formation of inflammatory mediators. The aim of this study was to determine which antioxidant compounds were most effective in ameliorating the stimulation of phospholipid turnover by oxidative stress. U937 cells were supplemented with eicosapentaenoic acid and either ascorbic acid, alpha-tocopherol, beta-carotene or astaxanthin prior to being challenged with oxidant. Although all antioxidants were found to be effective in decreasing oxidant-stimulated peroxide formation, only alpha-tocopherol significantly decreased oxidant-stimulated release of 3H-labeled arachidonic acid (AA), while ascorbic acid markedly increased release. All antioxidants except alpha-tocopherol decreased oxidant-stimulated 3H-AA uptake. Our data suggest that antioxidants are not equally effective in combating the effects of oxidative stress upon membrane phospholipid turnover, and that optimal protection will require mixtures of antioxidants.
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Affiliation(s)
- Oluwakemi Obajimi
- Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Oban, Scotland
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Zhu D, Lai Y, Shelat PB, Hu C, Sun GY, Lee JCM. Phospholipases A2 mediate amyloid-beta peptide-induced mitochondrial dysfunction. J Neurosci 2006; 26:11111-9. [PMID: 17065451 PMCID: PMC6674660 DOI: 10.1523/jneurosci.3505-06.2006] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Mitochondrial dysfunction has been implicated in the pathophysiology of Alzheimer's disease (AD) brains. To unravel the mechanism(s) underlying this dysfunction, we demonstrate that phospholipases A2 (PLA2s), namely the cytosolic and the calcium-independent PLA2s (cPLA2 and iPLA2), are key enzymes mediating oligomeric amyloid-beta peptide (Abeta(1-42))-induced loss of mitochondrial membrane potential and increase in production of reactive oxygen species from mitochondria in astrocytes. Whereas the action of iPLA2 is immediate, the action of cPLA2 requires a lag time of approximately 12-15 min, probably the time needed for initiating signaling pathways for the phosphorylation and translocation of cPLA2 to mitochondria. Western blot analysis indicated the ability of oligomeric Abeta(1-42) to increase phosphorylation of cPLA2 in astrocytes through the NADPH oxidase and mitogen-activated protein kinase pathways. The involvement of PLA2 in Abeta(1-42)-mediated perturbations of mitochondrial function provides new insights to the decline in mitochondrial function, leading to impairment in ATP production and increase in oxidative stress in AD brains.
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Affiliation(s)
| | - Yinzhi Lai
- Departments of Biological Engineering and
| | | | - Chunhua Hu
- Biochemistry, University of Missouri, Columbia, Missouri 65211
| | - Grace Y. Sun
- Biochemistry, University of Missouri, Columbia, Missouri 65211
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41
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Farooqui AA, Ong WY, Horrocks LA. Inhibitors of brain phospholipase A2 activity: their neuropharmacological effects and therapeutic importance for the treatment of neurologic disorders. Pharmacol Rev 2006; 58:591-620. [PMID: 16968951 DOI: 10.1124/pr.58.3.7] [Citation(s) in RCA: 236] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The phospholipase A(2) family includes secretory phospholipase A(2), cytosolic phospholipase A(2), plasmalogen-selective phospholipase A(2), and calcium-independent phospholipase A(2). It is generally thought that the release of arachidonic acid by cytosolic phospholipase A(2) is the rate-limiting step in the generation of eicosanoids and platelet activating factor. These lipid mediators play critical roles in the initiation and modulation of inflammation and oxidative stress. Neurological disorders, such as ischemia, spinal cord injury, Alzheimer's disease, multiple sclerosis, prion diseases, and epilepsy are characterized by inflammatory reactions, oxidative stress, altered phospholipid metabolism, accumulation of lipid peroxides, and increased phospholipase A(2) activity. Increased activities of phospholipases A(2) and generation of lipid mediators may be involved in oxidative stress and neuroinflammation associated with the above neurological disorders. Several phospholipase A(2) inhibitors have been recently discovered and used for the treatment of ischemia and other neurological diseases in cell culture and animal models. At this time very little is known about in vivo neurochemical effects, mechanism of action, or toxicity of phospholipase A(2) inhibitors in human or animal models of neurological disorders. In kainic acid-mediated neurotoxicity, the activities of phospholipase A(2) isoforms and their immunoreactivities are markedly increased and phospholipase A(2) inhibitors, quinacrine and chloroquine, arachidonyl trifluoromethyl ketone, bromoenol lactone, cytidine 5-diphosphoamines, and vitamin E, not only inhibit phospholipase A(2) activity and immunoreactivity but also prevent neurodegeneration, suggesting that phospholipase A(2) is involved in the neurodegenerative process. This also suggests that phospholipase A(2) inhibitors can be used as neuroprotectants and anti-inflammatory agents against neurodegenerative processes in neurodegenerative diseases.
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Affiliation(s)
- Akhlaq A Farooqui
- Department of Molecular and Cellular Biochemistry, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
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42
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González A, Granados MP, Pariente JA, Salido GM. H2O2 mobilizes Ca2+ from agonist- and thapsigargin-sensitive and insensitive intracellular stores and stimulates glutamate secretion in rat hippocampal astrocytes. Neurochem Res 2006; 31:741-50. [PMID: 16794860 DOI: 10.1007/s11064-006-9078-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2006] [Indexed: 11/26/2022]
Abstract
The effect of hydrogen peroxide (H2O2) on cytosolic free calcium concentration ([Ca2+]c) as well as its effect on glutamate secretion in rat hippocampal astrocytes have been the aim of the present research. Our results show that 100 microM H2O2 induces an increase in [Ca2+]c, that remains at an elevated level while the oxidant is present in the perfusion medium, due to its release from intracellular stores as it was observed in the absence of extracellular Ca2+, followed by a significant increase in glutamate secretion. Ca2+-mobilization in response to the oxidant could only be reduced by thapsigargin plus FCCP, indicating that the Ca2+-mobilizable pool by H2O2 includes both endoplasmic reticulum and mitochondria. We conclude that ROS in hippocampal astrocytes might contribute to an elevation of resting [Ca2+]c which, in turn, could lead to a maintained secretion of the excitatory neurotransmitter glutamate, which has been considered a situation potentially leading to neurotoxicity in the hippocampus.
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Affiliation(s)
- Antonio González
- Department of Physiology, University of Extremadura, Avenida Universidad s/n, E-10071 Cáceres, Spain.
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43
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Wang Q, Yu S, Simonyi A, Sun GY, Sun AY. Kainic acid-mediated excitotoxicity as a model for neurodegeneration. Mol Neurobiol 2006; 31:3-16. [PMID: 15953808 DOI: 10.1385/mn:31:1-3:003] [Citation(s) in RCA: 268] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2004] [Accepted: 11/15/2004] [Indexed: 02/06/2023]
Abstract
Neuronal excitation involving the excitatory glutamate receptors is recognized as an important underlying mechanism in neurodegenerative disorders. Excitation resulting from stimulation of the ionotropic glutamate receptors is known to cause the increase in intracellular calcium and trigger calcium-dependent pathways that lead to neuronal apoptosis. Kainic acid (KA) is an agonist for a subtype of ionotropic glutamate receptor, and administration of KA has been shown to increase production of reactive oxygen species, mitochondrial dysfunction, and apoptosis in neurons in many regions of the brain, particularly in the hippocampal subregions of CA1 and CA3, and in the hilus of dentate gyrus (DG). Systemic injection of KA to rats also results in activation of glial cells and inflammatory responses typically found in neurodegenerative diseases. KA-induced selective vulnerability in the hippocampal neurons is related to the distribution and selective susceptibility of the AMPA/kainate receptors in the brain. Recent studies have demonstrated ability of KA to alter a number of intracellular activities, including accumulation of lipofuscin-like substances, induction of complement proteins, processing of amyloid precursor protein, and alteration of tau protein expression. These studies suggest that KA-induced excitotoxicity can be used as a model for elucidating mechanisms underlying oxidative stress and inflammation in neurodegenerative diseases. The focus of this review is to summarize studies demonstrating KA-induced excitotoxicity in the central nervous system and possible intervention by anti-oxidants.
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Affiliation(s)
- Qun Wang
- Department of Medical Pharmacology, University of Missouri School of Medicine, Columbia, MO, USA
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Strokin M, Chechneva O, Reymann KG, Reiser G. Neuroprotection of rat hippocampal slices exposed to oxygen–glucose deprivation by enrichment with docosahexaenoic acid and by inhibition of hydrolysis of docosahexaenoic acid-containing phospholipids by calcium independent phospholipase A2. Neuroscience 2006; 140:547-53. [PMID: 16563639 DOI: 10.1016/j.neuroscience.2006.02.026] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2005] [Revised: 02/10/2006] [Accepted: 02/10/2006] [Indexed: 11/25/2022]
Abstract
Polyunsaturated fatty acids play an important role in the development of pathological states in brain after hypoxia/ischemia. Here, we investigated the role of docosahexaenoic acid (22:6n-3) in brain phospholipids for neuronal survival. We used organotypic cultures of rat brain hippocampal slices exposed to 40 min of oxygen-glucose deprivation, to study the consequences of experimental ischemia. In [14C]docosahexaenoic acid-labeled cultures, oxygen-glucose deprivation induced significant release of radioactive docosahexaenoic acid. This release could be blocked by the selective inhibitor of the Ca2+-independent phospholipase A2, 4-bromoenol lactone (10 microM), when it was added 30 min prior to oxygen-glucose deprivation. Addition of 4-bromoenol lactone at 30 min prior to oxygen-glucose deprivation markedly decreased the neuronal damage induced by oxygen-glucose deprivation. The protective effect was substantially higher in dentate gyrus than in CA1 and CA3 areas. Enrichment of the hippocampal tissue with docosahexaenoic acid by incubation with 10 microM docosahexaenoic acid for 24 h exerted the same neuroprotective effect, which was observed after treatment with 4-bromoenol lactone. In contrast to the 24 h-preincubation, simultaneous addition of docosahexaenoic acid with the onset of oxygen-glucose deprivation had no protective effect. This suggests that incorporation of docosahexaenoic acid into phospholipids is required for the protective effect observed. Then the possible involvement of arachidonic acid metabolism in docosahexaenoic acid-induced neuroprotection was tested. Inhibition of prostaglandin production by ibuprofen produced no change in neuroprotection after 24-h incubation of the hippocampal slices with docosahexaenoic acid. Simultaneous inhibition of Ca2+-independent and Ca2+-dependent phospholipases A2 by treatment with the general phospholipase A2 inhibitor methyl arachidonyl fluorophosphonate (3 microM, 30 min prior to oxygen-glucose deprivation) resulted in significant enhancement of the neuroprotective effect in the dentate gyrus, but not in the CA1 and CA3 areas. In summary, the results reported here indicate that docosahexaenoic acid and docosahexaenoic acid-containing phospholipids provide potent protection against neurodegeneration after hypoxia/hypoglycemia. Furthermore, our data suggest that Ca2+-independent phospholipase A2, the isoform, which has been largely ignored so far, is a possible target for treatment of ischemia-related pathologies in brain.
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Affiliation(s)
- M Strokin
- Otto-von-Guericke-Universität Magdeburg, Medizinische Fakultät, Institut für Neurobiochemie, Leipziger Strasse 44, D-39120, Magdeburg, Germany
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45
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Takano T, Tian GF, Peng W, Lou N, Libionka W, Han X, Nedergaard M. Astrocyte-mediated control of cerebral blood flow. Nat Neurosci 2005; 9:260-7. [PMID: 16388306 DOI: 10.1038/nn1623] [Citation(s) in RCA: 813] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2005] [Accepted: 12/02/2005] [Indexed: 12/12/2022]
Abstract
Local increase in blood flow during neural activity forms the basis for functional brain imaging, but its mechanism remains poorly defined. Here we show that cortical astrocytes in vivo possess a powerful mechanism for rapid vasodilation. We imaged the activity of astrocytes labeled with the calcium (Ca(2+))-sensitive indicator rhod-2 in somatosensory cortex of adult mice. Photolysis of caged Ca(2+) in astrocytic endfeet ensheathing the vessel wall was associated with an 18% increase in arterial cross-section area that corresponded to a 37% increase in blood flow. Vasodilation occurred with a latency of only 1-2 s, and both indomethacin and the cyclooxygenase-1 inhibitor SC-560 blocked the photolysis-induced hyperemia. These observations implicate astrocytes in the control of local microcirculation and suggest that one of their physiological roles is to mediate vasodilation in response to increased neural activity.
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Affiliation(s)
- Takahiro Takano
- Center for Aging and Developmental Biology, Department of Neurosurgery, University of Rochester Medical School, 601 Elmwood Avenue, Rochester, New York 14642, USA.
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46
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Chalimoniuk M, Głowacka J, Zabielna A, Eckert A, Strosznajder JB. Nitric oxide alters arachidonic acid turnover in brain cortex synaptoneurosomes. Neurochem Int 2005; 48:1-8. [PMID: 16216387 DOI: 10.1016/j.neuint.2005.08.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Accepted: 08/24/2005] [Indexed: 10/25/2022]
Abstract
Nitric oxide (NO) and arachidonic acid (AA) and also its metabolites are very important inter- and intracellular second messengers. They are involved in mechanisms of learning and memory. However, liberated in excessive amount in brain ischemia, Parkinson and Alzheimer diseases they are responsible for cell degeneration and death. Previously, we could show that Alzheimer disease's amyloid-beta protein enhanced nitric oxide liberation. The role of NO in AA metabolism is till now not well understood. Therefore, the aim of the present study was to investigate the mechanisms of NO-evoked activation of AA release and inhibition of AA incorporation into phospholipids of cortical rat brain synaptoneurosomes. The studies were carried out using NO donors, butyryl-cGMP (b-cGMP) and H2O2. All these compounds enhanced AA liberation from phosphatydilinositol (PI) and phosphatidylcholine (PC). Protein kinase ERK1/2, protein kinase C (PKC), cGMP-dependent protein kinase G (PKG) were involved in basal and NO-induced cytosolic phospholipase A2 (cPLA2) activation. Moreover, NO donors, b-cGMP and hydrogen peroxide (H2O2) exerted inhibitory effect on AA incorporation into PI and PC influencing arachidonyl-CoA transferase (AA-CoA-T) activity. AA-CoA synthase (AA-CoA-S) activity did not change. Specific inhibitors of protein kinase ERK1/2 (UO126), PKC (GF109203X), PKG (KT5823) had no effect on NO-mediated lowering of AA incorporation into PI and PC but inhibited the basal AA-CoA-S activity. Our data indicated that AA (10 microM) itself markedly decreased AA incorporation by about 50% into phospholipids of synaptoneurosomes membranes. Increasing release of AA and its metabolites causes the lowering of AA incorporation evoked by NO, b-cGMP and H2O2. Antioxidant, Resveratrol (100 microM) prevented NO- and cGMP-evoked inhibition of AA incorporation. These results suggest that NO affects the intracellular level of AA through alteration of cPLA2 and AA-CoA acyltransferase activities and may have an important implication in alterations of nerve endings properties and function.
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Affiliation(s)
- Małgorzata Chalimoniuk
- Department of Cellular Signaling, Medical Research Centre, Polish Academy of Sciences, Pawińskiego Street 5, 02-106 Warsaw, Poland.
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47
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Chlopicki S, Olszanecki R, Janiszewski M, Laurindo FRM, Panz T, Miedzobrodzki J. Functional role of NADPH oxidase in activation of platelets. Antioxid Redox Signal 2004; 6:691-8. [PMID: 15242549 DOI: 10.1089/1523086041361640] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Involvement of phagocyte NADPH oxidase in host defense response is well established. In contrast, little is known about the functional role of NADPH oxidase in platelets. In this study, we analyzed involvement of platelet NADPH oxidase in aggregation of human platelets and in amplification of production of reactive oxygen species (ROS) by activated human neutrophils. Apocynin, a known NADPH oxidase inhibitor, as well as superoxide dismutase mimetic Mn(III)tetrakis(1-methyl-1-pyridyl)porphyrin, inhibited ROS generation by collagen-activated platelets, collagen-induced aggregation of platelets, as well as collagen-induced release of thromboxane B2. These data suggest the key role of intracellular ROS derived from NADPH oxidase in the control of thromboxane A2 (TXA2) production in platelets stimulated by collagen. Apocynin also inhibited thrombin-induced ROS production and thrombin-induced platelet aggregation. Activation of neutrophils with latex resulted in an outburst of ROS that was inhibited by apocynin. ROS production by latex-stimulated platelets was modest and also inhibited by apocynin. However, when a mixture of platelets and neutrophils was stimulated with latex, ROS production was three to six times higher in comparison with activation of neutrophils alone. Platelet-dependent augmentation of neutrophil ROS production was abrogated by TXA2 synthase inhibitor (furegrelate, 1 microM) or by aspirin (300 microM). In summary, NADPH oxidase in platelets seems to play a major role as an intracellular signaling mechanism in the activation of platelets. However, in host defense response involving neutrophils and platelets, platelets enhance ROS production by neutrophils and possibly their cytotoxic potential via the release of TXA2, which in turn in platelets is not affected by the extracellular release of free radicals.
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Affiliation(s)
- Stefan Chlopicki
- Department of Experimental Pharmacology, Jagiellonian University Medical College, Krakow, Poland.
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48
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Abstract
Phospholipase A2 (PLA2) belongs to a family of enzymes that catalyze the cleavage of fatty acids from the sn-2 position of phospholipids. There are more than 19 different isoforms of PLA2 in the mammalian system, but recent studies have focused on three major groups, namely, the group IV cytosolic PLA2, the group II secretory PLA2 (sPLA2), and the group VI Ca(2+)-independent PLA2. These PLA2s are involved in a complex network of signaling pathways that link receptor agonists, oxidative agents, and proinflammatory cytokines to the release of arachidonic acid (AA) and the synthesis of eicosanoids. PLA2s acting on membrane phospholipids have been implicated in intracellular membrane trafficking, differentiation, proliferation, and apoptotic processes. All major groups of PLA2 are present in the central nervous system (CNS). Therefore, this review is focused on PLA2 and AA release in neural cells, especially in astrocytes and neurons. In addition, because many neurodegenerative diseases are associated with increased oxidative and inflammatory responses, an attempt was made to include studies on PLA2 in cerebral ischemia, Alzheimer's disease, and neuronal injury due to excitotoxic agents. Information from these studies has provided clear evidence for the important role of PLA2 in regulating physiological and pathological functions in the CNS.
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Affiliation(s)
- Grace Y Sun
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA.
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49
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Abstract
The catalytic activity of calcium-independent phospholipase A2 (iPLA2), which is classified as a group VI PLA2, is regulated by protein kinase C, calmodulin, and others such as reactive oxygen species. Numerous findings have shown that iPLA2 is involved in stimulus-induced arachidonic acid release and lysophospholipid generation, although the participation is dependent upon the cell type and stimulus. The catalytic action of iPLA2 is known to be responsible for phospholipid remodeling as a housekeeping function. However, it has been widely accepted that arachidonic acid and lysophospholipid generated by iPLA2 act as a signaling molecule in cellular functions. Those include eicosanoid production, glucose-induced insulin secretion, Fas-induced apoptosis, cellular proliferation, membrane traffic in fusion, contribution to myocardial ischemia, and others. In this review, the functional role of iPLA2 in cellular responses upon stimulation is the focus.
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Affiliation(s)
- Satoshi Akiba
- Department of Pathological Biochemistry, Kyoto Pharmaceutical University, Kyoto, Japan
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50
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Bazan NG. Synaptic lipid signaling: significance of polyunsaturated fatty acids and platelet-activating factor. J Lipid Res 2003; 44:2221-33. [PMID: 13130128 DOI: 10.1194/jlr.r300013-jlr200] [Citation(s) in RCA: 205] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Neuronal cellular and intracellular membranes are rich in specialized phospholipids that are reservoirs of lipid messengers released by specific phospholipases and stimulated by neurotransmitters, neurotrophic factors, cytokines, membrane depolarization, ion channel activation, etc. Secretory phospholipases A2 may be both intercellular messengers and generators of lipid messengers. The highly networked nervous system includes cells (e.g., astrocytes, oligodendrocytes, microglial cells, endothelial microvascular cells) that extensively interact with neurons; several lipid messengers participate in these interactions. This review highlights modulation of postsynaptic membrane excitability and long-term synaptic plasticity by cyclooxygenase-2-generated prostaglandin E2, arachidonoyldiacylcylglycerol, and arachidonic acid-containing endocannabinoids. The peroxidation of docosahexaenoic acid (DHA), a critical component of excitable membranes in brain and retina, is promoted by oxidative stress. DHA is also the precursor of enzyme-derived, neuroprotective docosanoids. The phospholipid platelet-activating factor is a retrograde messenger of long-term potentiation, a modulator of glutamate release, and an upregulator of memory formation. Lipid messengers modulate signaling cascades and contribute to cellular differentiation, function, protection, and repair in the nervous system. Lipidomic neurobiology will advance our knowledge of the brain, spinal cord, retina, and peripheral nerve function and diseases that affect them, and new discoveries on networks of signaling in health and disease will likely lead to novel therapeutic interventions.
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Affiliation(s)
- Nicolas G Bazan
- Louisiana State University Neuroscience Center of Excellence and Department of Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, LA, USA.
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