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Maniscalchi A, Benzi Juncos ON, Conde MA, Funk MI, Fermento ME, Facchinetti MM, Curino AC, Uranga RM, Alza NP, Salvador GA. New insights on neurodegeneration triggered by iron accumulation: Intersections with neutral lipid metabolism, ferroptosis, and motor impairment. Redox Biol 2024; 71:103074. [PMID: 38367511 PMCID: PMC10879836 DOI: 10.1016/j.redox.2024.103074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/28/2023] [Accepted: 02/03/2024] [Indexed: 02/19/2024] Open
Abstract
Brain iron accumulation constitutes a pathognomonic indicator in several neurodegenerative disorders. Metal accumulation associated with dopaminergic neuronal death has been documented in Parkinson's disease. Through the use of in vivo and in vitro models, we demonstrated that lipid dysregulation manifests as a neuronal and glial response during iron overload. In this study, we show that cholesterol content and triacylglycerol (TAG) hydrolysis were strongly elevated in mice midbrain. Lipid cacostasis was concomitant with the loss of dopaminergic neurons, astrogliosis and elevated expression of α-synuclein. Exacerbated lipid peroxidation and markers of ferroptosis were evident in the midbrain from mice challenged with iron overload. An imbalance in the activity of lipolytic and acylation enzymes was identified, favoring neutral lipid hydrolysis, and consequently reducing TAG and cholesteryl ester levels. Notably, these observed alterations were accompanied by motor impairment in iron-treated mice. In addition, neuronal and glial cultures along with their secretomes were used to gain further insight into the mechanism underlying TAG hydrolysis and cholesterol accumulation as cellular responses to iron accumulation. We demonstrated that TAG hydrolysis in neurons is triggered by astrocyte secretomes. Moreover, we found that the ferroptosis inhibitor, ferrostatin-1, effectively prevents cholesterol accumulation both in neurons and astrocytes. Taken together, these results indicate that lipid disturbances occur in iron-overloaded mice as a consequence of iron-induced oxidative stress and depend on neuron-glia crosstalk. Our findings suggest that developing therapies aimed at restoring lipid homeostasis may lead to specific treatment for neurodegeneration associated with ferroptosis and brain iron accumulation.
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Affiliation(s)
- Athina Maniscalchi
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km7 B8000FWB, Bahía Blanca, Argentina
| | - Oriana N Benzi Juncos
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km7 B8000FWB, Bahía Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Melisa A Conde
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km7 B8000FWB, Bahía Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Melania I Funk
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km7 B8000FWB, Bahía Blanca, Argentina
| | - María E Fermento
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km7 B8000FWB, Bahía Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - María M Facchinetti
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km7 B8000FWB, Bahía Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Alejandro C Curino
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km7 B8000FWB, Bahía Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Romina M Uranga
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km7 B8000FWB, Bahía Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Natalia P Alza
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km7 B8000FWB, Bahía Blanca, Argentina; Departamento de Química - UNS, Bahía Blanca, Argentina
| | - Gabriela A Salvador
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km7 B8000FWB, Bahía Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina.
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Wang K, Zhong Y, Yang F, Hu C, Liu X, Zhu Y, Yao K. Causal Effects of N-6 Polyunsaturated Fatty Acids on Age-related Macular Degeneration: A Mendelian Randomization Study. J Clin Endocrinol Metab 2021; 106:e3565-e3572. [PMID: 33982092 DOI: 10.1210/clinem/dgab338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Indexed: 12/23/2022]
Abstract
CONTEXT Although the role of n-6 polyunsaturated fatty acids (PUFAs) in age-related macular degeneration (AMD) has been studied in previous observational studies, the precise manner in which 1 or more n-6 PUFAs account for this relationship remains unclear. OBJECTIVE Using genetic instruments for n-6 PUFAs traits implemented through mendelian randomization (MR), we aimed to study possible causal associations between n-6 PUFAs and AMD. METHODS The 2-sample MR method was used to obtain unconfounded causal estimates. We selected genetic variants strongly associated (P < 5 × 10-8) with circulating linoleic acid (LA) and arachidonic acid (AA) from a study involving 8 631 individuals and applied to an AMD case-control study (33 526 participants and 16 144 cases). The weighted median and MR Egger methods were used for the sensitivity analysis. RESULTS Our MR analysis suggested that circulating LA was a causal protective factor for AMD, with an odds ratio (OR) estimate of 0.967 (95% CI 0.945 to 0.990; P = .005) per percentage in total fatty acid increase in LA. In contrast, higher genetically predicted circulating AA causally increased the AMD risk (OR = 1.034; 95% CI 1.012 to 1.056; P = .002). Sensitivity analysis provided no indication of unknown pleiotropy. The findings from different single-nucleotide polymorphism selections and analytic methods were consistent, suggesting the robustness of the causal associations. CONCLUSION Our study provided genetic evidence that circulating LA accounted for protective effects of n-6 PUFAs against the risk of AMD, whereas AA was responsible for deleterious effects on higher AMD risk.
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Affiliation(s)
- Kai Wang
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Yueyang Zhong
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Fangkun Yang
- Department of Cardiology of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Chenyang Hu
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Xin Liu
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Yanan Zhu
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China
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Phospholipase iPLA 2β averts ferroptosis by eliminating a redox lipid death signal. Nat Chem Biol 2021; 17:465-476. [PMID: 33542532 PMCID: PMC8152680 DOI: 10.1038/s41589-020-00734-x] [Citation(s) in RCA: 166] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 12/23/2020] [Indexed: 12/17/2022]
Abstract
Ferroptosis, triggered by discoordination of iron, thiols and lipids, leads to the accumulation of 15-hydroperoxy (Hp)-arachidonoyl-phosphatidylethanolamine (15-HpETE-PE), generated by complexes of 15-lipoxygenase (15-LOX) and a scaffold protein, phosphatidylethanolamine (PE)-binding protein (PEBP)1. As the Ca2+-independent phospholipase A2β (iPLA2β, PLA2G6 or PNPLA9 gene) can preferentially hydrolyze peroxidized phospholipids, it may eliminate the ferroptotic 15-HpETE-PE death signal. Here, we demonstrate that by hydrolyzing 15-HpETE-PE, iPLA2β averts ferroptosis, whereas its genetic or pharmacological inactivation sensitizes cells to ferroptosis. Given that PLA2G6 mutations relate to neurodegeneration, we examined fibroblasts from a patient with a Parkinson's disease (PD)-associated mutation (fPDR747W) and found selectively decreased 15-HpETE-PE-hydrolyzing activity, 15-HpETE-PE accumulation and elevated sensitivity to ferroptosis. CRISPR-Cas9-engineered Pnpla9R748W/R748W mice exhibited progressive parkinsonian motor deficits and 15-HpETE-PE accumulation. Elevated 15-HpETE-PE levels were also detected in midbrains of rotenone-infused parkinsonian rats and α-synuclein-mutant SncaA53T mice, with decreased iPLA2β expression and a PD-relevant phenotype. Thus, iPLA2β is a new ferroptosis regulator, and its mutations may be implicated in PD pathogenesis.
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Iglesias González PA, Conde MA, González-Pardo V, Uranga RM, Salvador GA. In vitro 6-hydroxydopamine-induced neurotoxicity: New insights on NFκB modulation. Toxicol In Vitro 2019; 60:400-411. [DOI: 10.1016/j.tiv.2019.06.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/21/2019] [Accepted: 06/23/2019] [Indexed: 10/26/2022]
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Tenconi PE, Bermúdez V, Oresti GM, Giusto NM, Salvador GA, Mateos MV. High glucose-induced phospholipase D activity in retinal pigment epithelium cells: New insights into the molecular mechanisms of diabetic retinopathy. Exp Eye Res 2019; 184:243-257. [PMID: 31059692 DOI: 10.1016/j.exer.2019.04.028] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 04/05/2019] [Accepted: 04/30/2019] [Indexed: 02/02/2023]
Abstract
Chronic hyperglycemia, oxidative stress and inflammation are key players in the pathogenesis of diabetic retinopathy (DR). In this work we study the role of phospholipase D (PLD) pathway in an in vitro model of high glucose (HG)-induced damage. To this end, we exposed human retinal pigment epithelium (RPE) cell lines (ARPE-19 and D407) to HG concentrations (16.5 or 33 mM) or to normal glucose concentration (NG, 5.5 mM) for 4, 24 or 72 h. Exposure to HG increased reactive oxygen species levels and caspase-3 cleavage and reduced cell viability after 72 h of incubation. In addition, short term HG exposure (4 h) induced the activation of early events, that involve PLD and ERK1/2 signaling, nuclear factor kappa B (NFκB) nuclear translocation and IκB phosphorylation. The increment in pro-inflammatory interleukins (IL-6 and IL-8) and cyclooxygenase-2 (COX-2) mRNA levels was observed after 24 h of HG exposure. The effect of selective pharmacological PLD1 (VU0359595) and PLD2 (VU0285655-1) inhibitors demonstrated that ERK1/2 and NFκB activation were downstream events of both PLD isoforms. The increment in IL-6 and COX-2 mRNA levels induced by HG was reduced to control levels in cells pre-incubated with both PLD inhibitors. Furthermore, the inhibition of PLD1, PLD2 and MEK/ERK pathway prevented the loss of cell viability and the activation of caspase-3 induced by HG. In conclusion, our findings demonstrate that PLD1 and PLD2 mediate the inflammatory response triggered by HG in RPE cells, pointing to their potential use as a therapeutic target for DR treatment.
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Affiliation(s)
- Paula E Tenconi
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 8000, Bahía, Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia (DBByF), Universidad Nacional del Sur (UNS), 8000, Bahía, Blanca, Argentina
| | - Vicente Bermúdez
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 8000, Bahía, Blanca, Argentina
| | - Gerardo M Oresti
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 8000, Bahía, Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia (DBByF), Universidad Nacional del Sur (UNS), 8000, Bahía, Blanca, Argentina
| | - Norma M Giusto
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 8000, Bahía, Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia (DBByF), Universidad Nacional del Sur (UNS), 8000, Bahía, Blanca, Argentina
| | - Gabriela A Salvador
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 8000, Bahía, Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia (DBByF), Universidad Nacional del Sur (UNS), 8000, Bahía, Blanca, Argentina
| | - Melina V Mateos
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 8000, Bahía, Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia (DBByF), Universidad Nacional del Sur (UNS), 8000, Bahía, Blanca, Argentina.
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Unraveling the Burden of Iron in Neurodegeneration: Intersections with Amyloid Beta Peptide Pathology. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:2850341. [PMID: 29581821 PMCID: PMC5831758 DOI: 10.1155/2018/2850341] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 12/17/2017] [Indexed: 12/14/2022]
Abstract
Iron overload is a hallmark of many neurodegenerative processes such as Alzheimer's, Parkinson's, and Huntington's diseases. Unbound iron accumulated as a consequence of brain aging is highly reactive with water and oxygen and produces reactive oxygen species (ROS) or free radicals. ROS are toxic compounds able to damage cell membranes, DNA, and mitochondria. Which are the mechanisms involved in neuronal iron homeostasis and in neuronal response to iron-induced oxidative stress constitutes a cutting-edge topic in metalloneurobiology. Increasing our knowledge about the underlying mechanisms that operate in iron accumulation and their consequences would shed light on the comprehension of the molecular events that participate in the pathophysiology of the abovementioned neurodegenerative diseases. In this review, current evidences about iron accumulation in the brain, the signaling mechanisms triggered by metal overload, as well as the interaction between amyloid β (Aβ) and iron, will be summarized.
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Sánchez Campos S, Rodríguez Diez G, Oresti GM, Salvador GA. Dopaminergic Neurons Respond to Iron-Induced Oxidative Stress by Modulating Lipid Acylation and Deacylation Cycles. PLoS One 2015; 10:e0130726. [PMID: 26076361 PMCID: PMC4468124 DOI: 10.1371/journal.pone.0130726] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 05/22/2015] [Indexed: 12/12/2022] Open
Abstract
Metal-imbalance has been reported as a contributor factor for the degeneration of dopaminergic neurons in Parkinson Disease (PD). Specifically, iron (Fe)-overload and copper (Cu) mis-compartmentalization have been reported to be involved in the injury of dopaminergic neurons in this pathology. The aim of this work was to characterize the mechanisms of membrane repair by studying lipid acylation and deacylation reactions and their role in oxidative injury in N27 dopaminergic neurons exposed to Fe-overload and Cu-supplementation. N27 dopaminergic neurons incubated with Fe (1mM) for 24 hs displayed increased levels of reactive oxygen species (ROS), lipid peroxidation and elevated plasma membrane permeability. Cu-supplemented neurons (10, 50 μM) showed no evidence of oxidative stress markers. A different lipid acylation profile was observed in N27 neurons pre-labeled with [3H] arachidonic acid (AA) or [3H] oleic acid (OA). In Fe-exposed neurons, AA uptake was increased in triacylglycerols (TAG) whereas its incorporation into the phospholipid (PL) fraction was diminished. TAG content was 40% higher in Fe-exposed neurons than in controls. This increase was accompanied by the appearance of Nile red positive lipid bodies. Contrariwise, OA incorporation increased in the PL fractions and showed no changes in TAG. Lipid acylation profile in Cu-supplemented neurons showed AA accumulation into phosphatidylserine and no changes in TAG. The inhibition of deacylation/acylation reactions prompted an increase in oxidative stress markers and mitochondrial dysfunction in Fe-overloaded neurons. These findings provide evidence about the participation of lipid acylation mechanisms against Fe-induced oxidative injury and postulate that dopaminergic neurons cleverly preserve AA in TAG in response to oxidative stress.
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Affiliation(s)
- Sofía Sánchez Campos
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Universidad Nacional del Sur (UNS) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Guadalupe Rodríguez Diez
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Universidad Nacional del Sur (UNS) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Gerardo Martín Oresti
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Universidad Nacional del Sur (UNS) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Gabriela Alejandra Salvador
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Universidad Nacional del Sur (UNS) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
- * E-mail:
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Mateos MV, Kamerbeek CB, Giusto NM, Salvador GA. The phospholipase D pathway mediates the inflammatory response of the retinal pigment epithelium. Int J Biochem Cell Biol 2014; 55:119-28. [DOI: 10.1016/j.biocel.2014.08.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 08/12/2014] [Accepted: 08/18/2014] [Indexed: 12/25/2022]
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Minhas G, Modgil S, Anand A. Role of iron in ischemia-induced neurodegeneration: mechanisms and insights. Metab Brain Dis 2014; 29:583-91. [PMID: 24615430 DOI: 10.1007/s11011-014-9522-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 02/26/2014] [Indexed: 12/31/2022]
Abstract
Iron is an important micronutrient for neuronal function and survival. It plays an essential role in DNA and protein synthesis, neurotransmission and electron transport chain due to its dual redox states. On the contrary, iron also catalyses the production of free radicals and hence, causes oxidative stress. Therefore, maintenance of iron homeostasis is very crucial and it involves a number of proteins in iron metabolism and transport that maintain the balance. In ischemic conditions large amount of iron is released and this free iron catalyzes production of more free radicals and hence, causing more damage. In this review we have focused on the iron transport and maintenance of iron homeostasis at large and also the effect of imbalance in iron homeostasis on retinal and brain tissue under ischemic conditions. The understanding of the proteins involved in the homeostasis imbalance will help in developing therapeutic strategies for cerebral as well retinal ischemia.
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Affiliation(s)
- Gillipsie Minhas
- Neuroscience Research Laboratory, Department of Neurology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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Rodríguez Diez G, Sánchez Campos S, Giusto N, Salvador G. Specific roles for Group V secretory PLA2 in retinal iron-induced oxidative stress. Implications for age-related macular degeneration. Exp Eye Res 2013; 113:172-81. [DOI: 10.1016/j.exer.2013.05.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 05/14/2013] [Accepted: 05/21/2013] [Indexed: 11/15/2022]
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Uranga RM, Katz S, Salvador GA. Enhanced phosphatidylinositol 3-kinase (PI3K)/Akt signaling has pleiotropic targets in hippocampal neurons exposed to iron-induced oxidative stress. J Biol Chem 2013; 288:19773-84. [PMID: 23687303 DOI: 10.1074/jbc.m113.457622] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The PI3K/Akt pathway is a key component in synaptic plasticity and neuronal survival. The aim of this work was to investigate the participation of the PI3K/Akt pathway and its outcome on different molecular targets such as glycogen synthase kinase 3β (GSK3β) and Forkhead box-O (FoxO) transcription factors during mild oxidative stress triggered by iron overload. The exposure of mouse hippocampal neurons (HT22) to different concentrations of Fe(2+) (25-200 μm) for 24 h led us to define a mild oxidative injury status (50 μm Fe(2+)) in which cell morphology showed changes typical of neuronal damage with increased lipid peroxidation and cellular oxidant levels but no alteration of cellular viability. There was a simultaneous increase in both Akt and GSK3β phosphorylation. Levels of phospho-FoxO3a (inactive form) increased in the cytosolic fraction of cells treated with iron in a PI3K-dependent manner. Moreover, PI3K and Akt translocated to the nucleus in response to oxidative stress. Iron-overloaded cells harboring a constitutively active form of Akt showed decreased oxidants levels. Indeed, GSH synthesis under oxidative stress conditions was regulated by activated Akt. Our results show that activation of the PI3K/Akt pathway during iron-induced neurotoxicity regulates multiple targets such as GSK3β, FoxO transcriptional activity, and glutathione metabolism, thus modulating the neuronal response to oxidative stress.
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Affiliation(s)
- Romina María Uranga
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur, 8000 Bahía Blanca, Argentina
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