Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 89
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nat Chem Biol ; 2021 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-33542532

RESUMO

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 A2ß (iPLA2ß, 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, iPLA2ß 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 iPLA2ß expression and a PD-relevant phenotype. Thus, iPLA2ß is a new ferroptosis regulator, and its mutations may be implicated in PD pathogenesis.

2.
Sci Transl Med ; 12(572)2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-33268511

RESUMO

Tumor recurrence years after seemingly successful treatment of primary tumors is one of the major causes of mortality in patients with cancer. Reactivation of dormant tumor cells is largely responsible for this phenomenon. Using dormancy models of lung and ovarian cancer, we found a specific mechanism, mediated by stress and neutrophils, that may govern this process. Stress hormones cause rapid release of proinflammatory S100A8/A9 proteins by neutrophils. S100A8/A9 induce activation of myeloperoxidase, resulting in accumulation of oxidized lipids in these cells. Upon release from neutrophils, these lipids up-regulate the fibroblast growth factor pathway in tumor cells, causing tumor cell exit from the dormancy and formation of new tumor lesions. Higher serum concentrations of S100A8/A9 were associated with shorter time to recurrence in patients with lung cancer after complete tumor resection. Targeting of S100A8/A9 or ß2-adrenergic receptors abrogated stress-induced reactivation of dormant tumor cells. These observations demonstrate a mechanism linking stress and specific neutrophil activation with early recurrence in cancer.

3.
Redox Biol ; 38: 101744, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-33126055

RESUMO

Hydroperoxy-eicosatetraenoyl-phosphatidylethanolamine (HpETE-PE) is a ferroptotic cell death signal. HpETE-PE is produced by the 15-Lipoxygenase (15LOX)/Phosphatidylethanolamine Binding Protein-1 (PEBP1) complex or via an Fe-catalyzed non-enzymatic radical reaction. Ferrostatin-1 (Fer-1), a common ferroptosis inhibitor, is a lipophilic radical scavenger but a poor 15LOX inhibitor arguing against 15LOX having a role in ferroptosis. In the current work, we demonstrate that Fer-1 does not affect 15LOX alone, however, it effectively inhibits HpETE-PE production by the 15LOX/PEBP1 complex. Computational molecular modeling shows that Fer-1 binds to the 15LOX/PEBP1 complex at three sites and could disrupt the catalytically required allosteric motions of the 15LOX/PEBP1 complex. Using nine ferroptosis cell/tissue models, we show that HpETE-PE is produced by the 15LOX/PEBP1 complex and resolve the long-existing Fer-1 anti-ferroptotic paradox.

4.
Proc Natl Acad Sci U S A ; 117(44): 27319-27328, 2020 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-33087576

RESUMO

The recently identified ferroptotic cell death is characterized by excessive accumulation of hydroperoxy-arachidonoyl (C20:4)- or adrenoyl (C22:4)- phosphatidylethanolamine (Hp-PE). The selenium-dependent glutathione peroxidase 4 (GPX4) inhibits ferroptosis, converting unstable ferroptotic lipid hydroperoxides to nontoxic lipid alcohols in a tissue-specific manner. While placental oxidative stress and lipotoxicity are hallmarks of placental dysfunction, the possible role of ferroptosis in placental dysfunction is largely unknown. We found that spontaneous preterm birth is associated with ferroptosis and that inhibition of GPX4 causes ferroptotic injury in primary human trophoblasts and during mouse pregnancy. Importantly, we uncovered a role for the phospholipase PLA2G6 (PNPLA9, iPLA2beta), known to metabolize Hp-PE to lyso-PE and oxidized fatty acid, in mitigating ferroptosis induced by GPX4 inhibition in vitro or by hypoxia/reoxygenation injury in vivo. Together, we identified ferroptosis signaling in the human and mouse placenta, established a role for PLA2G6 in attenuating trophoblastic ferroptosis, and provided mechanistic insights into the ill-defined placental lipotoxicity that may inspire PLA2G6-targeted therapeutic strategies.

5.
JCI Insight ; 5(15)2020 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-32584791

RESUMO

DCs are a critical component of immune responses in cancer primarily due to their ability to cross-present tumor-associated antigens. Cross-presentation by DCs in cancer is impaired, which may represent one of the obstacles for the success of cancer immunotherapies. Here, we report that polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) blocked cross-presentation by DCs without affecting direct presentation of antigens by these cells. This effect did not require direct cell-cell contact and was associated with transfer of lipids. Neutrophils (PMN) and PMN-MDSC transferred lipid to DCs equally well; however, PMN did not affect DC cross-presentation. PMN-MDSC generate oxidatively truncated lipids previously shown to be involved in impaired cross-presentation by DCs. Accumulation of oxidized lipids in PMN-MDSC was dependent on myeloperoxidase (MPO). MPO-deficient PMN-MDSC did not affect cross-presentation by DCs. Cross-presentation of tumor-associated antigens in vivo by DCs was improved in MDSC-depleted or tumor-bearing MPO-KO mice. Pharmacological inhibition of MPO in combination with checkpoint blockade reduced tumor progression in different tumor models. These data suggest MPO-driven lipid peroxidation in PMN-MDSC as a possible non-cell autonomous mechanism of inhibition of antigen cross-presentation by DCs and propose MPO as potential therapeutic target to enhance the efficacy of current immunotherapies for patients with cancer.

6.
Hepatology ; 2020 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-32438524

RESUMO

BACKGROUND AND AIMS: Iron is essential yet also highly chemically reactive and potentially toxic. The mechanisms that allow cells to use iron safely are not clear; defects in iron management are a causative factor in the cell-death pathway known as ferroptosis. Poly rC binding protein 1 (PCBP1) is a multifunctional protein that serves as a cytosolic iron chaperone, binding and transferring iron to recipient proteins in mammalian cells. Although PCBP1 distributes iron in cells, its role in managing iron in mammalian tissues remains open for study. The liver is highly specialized for iron uptake, utilization, storage, and secretion. APPROACH AND RESULTS: Mice lacking PCBP1 in hepatocytes exhibited defects in liver iron homeostasis with low levels of liver iron, reduced activity of iron enzymes, and misregulation of the cell-autonomous iron regulatory system. These mice spontaneously developed liver disease with hepatic steatosis, inflammation, and degeneration. Transcriptome analysis indicated activation of lipid biosynthetic and oxidative-stress response pathways, including the antiferroptotic mediator, glutathione peroxidase type 4. Although PCBP1-deleted livers were iron deficient, dietary iron supplementation did not prevent steatosis; instead, dietary iron restriction and antioxidant therapy with vitamin E prevented liver disease. PCBP1-deleted hepatocytes exhibited increased labile iron and production of reactive oxygen species (ROS), were hypersensitive to iron and pro-oxidants, and accumulated oxidatively damaged lipids because of the reactivity of unchaperoned iron. CONCLUSIONS: Unchaperoned iron in PCBP1-deleted mouse hepatocytes leads to production of ROS, resulting in lipid peroxidation (LPO) and steatosis in the absence of iron overload. The iron chaperone activity of PCBP1 is therefore critical for limiting the toxicity of cytosolic iron and may be a key factor in preventing the LPO that triggers the ferroptotic cell-death pathway.

7.
Sci Adv ; 6(12): eaay4361, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32219161

RESUMO

Biomaterials composed of extracellular matrix (ECM) provide both mechanical support and a reservoir of constructive signaling molecules that promote functional tissue repair. Recently, matrix-bound nanovesicles (MBVs) have been reported as an integral component of ECM bioscaffolds. Although liquid-phase extracellular vesicles (EVs) have been the subject of intense investigation, their similarity to MBV is limited to size and shape. Liquid chromatography-mass spectrometry (LC-MS)-based lipidomics and redox lipidomics were used to conduct a detailed comparison of liquid-phase EV and MBV phospholipids. Combined with comprehensive RNA sequencing and bioinformatic analysis of the intravesicular cargo, we show that MBVs are a distinct and unique subpopulation of EV and a distinguishing feature of ECM-based biomaterials. The results begin to identify the differential biologic activities mediated by EV that are secreted by tissue-resident cells and deposited within the ECM.


Assuntos
Vesículas Extracelulares , Lipidômica , Nanopartículas , Análise de Sequência de RNA , Células 3T3 , Animais , Materiais Biocompatíveis , Cromatografia Líquida , Matriz Extracelular , Ácidos Graxos/metabolismo , Lipidômica/métodos , Microextração em Fase Líquida , Camundongos , Fosfolipídeos/metabolismo , Frações Subcelulares
8.
Nat Chem Biol ; 16(3): 278-290, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32080625

RESUMO

Ferroptotic death is the penalty for losing control over three processes-iron metabolism, lipid peroxidation and thiol regulation-that are common in the pro-inflammatory environment where professional phagocytes fulfill their functions and yet survive. We hypothesized that redox reprogramming of 15-lipoxygenase (15-LOX) during the generation of pro-ferroptotic signal 15-hydroperoxy-eicosa-tetra-enoyl-phosphatidylethanolamine (15-HpETE-PE) modulates ferroptotic endurance. Here, we have discovered that inducible nitric oxide synthase (iNOS)/NO•-enrichment of activated M1 (but not alternatively activated M2) macrophages/microglia modulates susceptibility to ferroptosis. Genetic or pharmacologic depletion/inactivation of iNOS confers sensitivity on M1 cells, whereas NO• donors empower resistance of M2 cells to ferroptosis. In vivo, M1 phagocytes, in comparison to M2 phagocytes, exert higher resistance to pharmacologically induced ferroptosis. This resistance is diminished in iNOS-deficient cells in the pro-inflammatory conditions of brain trauma or the tumour microenvironment. The nitroxygenation of eicosatetraenoyl (ETE)-PE intermediates and oxidatively truncated species by NO• donors and/or suppression of NO• production by iNOS inhibitors represent a novel redox mechanism of regulation of ferroptosis in pro-inflammatory conditions.


Assuntos
Ferroptose/fisiologia , Macrófagos/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Animais , Araquidonato 15-Lipoxigenase/metabolismo , Araquidonato 15-Lipoxigenase/fisiologia , Morte Celular , Feminino , Ferro/metabolismo , Ferro/fisiologia , Leucotrienos/metabolismo , Peroxidação de Lipídeos/fisiologia , Peróxidos Lipídicos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/metabolismo , Óxido Nítrico Sintase Tipo II/fisiologia , Oxirredução , Espécies Reativas de Oxigênio/metabolismo
9.
J Leukoc Biol ; 106(1): 57-81, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31071242

RESUMO

In addition to the known prominent role of polyunsaturated (phospho)lipids as structural blocks of biomembranes, there is an emerging understanding of another important function of these molecules as a highly diversified signaling language utilized for intra- and extracellular communications. Technological developments in high-resolution mass spectrometry facilitated the development of a new branch of metabolomics, redox lipidomics. Analysis of lipid peroxidation reactions has already identified specific enzymatic mechanisms responsible for the biosynthesis of several unique signals in response to inflammation and regulated cell death programs. Obtaining comprehensive information about millions of signals encoded by oxidized phospholipids, represented by thousands of interactive reactions and pleiotropic (patho)physiological effects, is a daunting task. However, there is still reasonable hope that significant discoveries, of at least some of the important contributors to the overall overwhelmingly complex network of interactions triggered by inflammation, will lead to the discovery of new small molecule regulators and therapeutic modalities. For example, suppression of the production of AA-derived pro-inflammatory mediators, HXA3 and LTB4, by an iPLA2 γ inhibitor, R-BEL, mitigated injury associated with the activation of pro-inflammatory processes in animals exposed to whole-body irradiation. Further, technological developments promise to make redox lipidomics a powerful approach in the arsenal of diagnostic and therapeutic instruments for personalized medicine of inflammatory diseases and conditions.


Assuntos
Apoptose , Inflamação/metabolismo , Lipidômica , Transdução de Sinais/fisiologia , Animais , Ácidos Graxos Insaturados/metabolismo , Humanos , Inflamação/etiologia , Ferro/metabolismo , Peroxidação de Lipídeos , Oxirredução , Irradiação Corporal Total
10.
Nature ; 569(7754): 73-78, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30996346

RESUMO

Polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) are pathologically activated neutrophils that are crucial for the regulation of immune responses in cancer. These cells contribute to the failure of cancer therapies and are associated with poor clinical outcomes. Despite recent advances in the understanding of PMN-MDSC biology, the mechanisms responsible for the pathological activation of neutrophils are not well defined, and this limits the selective targeting of these cells. Here we report that mouse and human PMN-MDSCs exclusively upregulate fatty acid transport protein 2 (FATP2). Overexpression of FATP2 in PMN-MDSCs was controlled by granulocyte-macrophage colony-stimulating factor, through the activation of the STAT5 transcription factor. Deletion of FATP2 abrogated the suppressive activity of PMN-MDSCs. The main mechanism of FATP2-mediated suppressive activity involved the uptake of arachidonic acid and the synthesis of prostaglandin E2. The selective pharmacological inhibition of FATP2 abrogated the activity of PMN-MDSCs and substantially delayed tumour progression. In combination with checkpoint inhibitors, FATP2 inhibition blocked tumour progression in mice. Thus, FATP2 mediates the acquisition of immunosuppressive activity by PMN-MDSCs and represents a target to inhibit the functions of PMN-MDSCs selectively and to improve the efficiency of cancer therapy.


Assuntos
Proteínas de Transporte de Ácido Graxo/metabolismo , Ácidos Graxos/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , Neutrófilos/metabolismo , Idoso , Animais , Ácido Araquidônico/metabolismo , Dinoprostona/metabolismo , Proteínas de Transporte de Ácido Graxo/antagonistas & inibidores , Feminino , Humanos , Metabolismo dos Lipídeos , Lipídeos , Masculino , Camundongos , Pessoa de Meia-Idade , Neutrófilos/patologia , Fator de Transcrição STAT5/metabolismo
11.
Chem Phys Lipids ; 221: 93-107, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30928338

RESUMO

Aerobic life is based on numerous metabolic oxidation reactions as well as biosynthesis of oxygenated signaling compounds. Among the latter are the myriads of oxygenated lipids including a well-studied group of polyunsaturated fatty acids (PUFA) - octadecanoids, eicosanoids, and docosanoids. During the last two decades, remarkable progress in liquid-chromatography-mass spectrometry has led to significant progress in the characterization of oxygenated PUFA-containing phospholipids, thus designating the emergence of a new field of lipidomics, redox lipidomics. Although non-enzymatic free radical reactions of lipid peroxidation have been mostly associated with the aberrant metabolism typical of acute injury or chronic degenerative processes, newly accumulated evidence suggests that enzymatically catalyzed (phospho)lipid oxygenation reactions are essential mechanisms of many physiological pathways. In this review, we discuss a variety of contemporary protocols applicable for identification and quantitative characterization of different classes of peroxidized (phospho)lipids. We describe applications of different types of LCMS for analysis of peroxidized (phospho)lipids, particularly cardiolipins and phosphatidylethanolalmines, in two important types of programmed cell death - apoptosis and ferroptosis. We discuss the role of peroxidized phosphatidylserines in phagocytotic signaling. We exemplify the participation of peroxidized neutral lipids, particularly tri-acylglycerides, in immuno-suppressive signaling in cancer. We also consider new approaches to exploring the spatial distribution of phospholipids in the context of their oxidizability by MS imaging, including the latest achievements in high resolution imaging techniques. We present innovative approaches to the interpretation of LC-MS data, including audio-representation analysis. Overall, we emphasize the role of redox lipidomics as a communication language, unprecedented in diversity and richness, through the analysis of peroxidized (phospho)lipids.


Assuntos
Lipidômica , Fosfolipídeos/química , Cromatografia Líquida , Humanos , Espectrometria de Massas , Oxirredução
12.
Structure ; 27(5): 806-815.e4, 2019 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-30879887

RESUMO

The peroxidation of cardiolipins by reactive oxygen species, which is regulated and enhanced by cytochrome c (cyt c), is a critical signaling event in mitochondrial apoptosis. We probe the molecular underpinnings of this mitochondrial death signal through structural and functional studies of horse heart cyt c binding to mixed-lipid membranes containing cardiolipin with mono- and polyunsaturated acyl chains. Lipidomics reveal the selective oxidation of polyunsaturated fatty acid (PUFA) cardiolipin (CL), while multidimensional solid-state NMR probes the structure and dynamics of the membrane and the peripherally bound protein. The hydrophilic milieu at the membrane interface stabilizes a native-like fold, but also leads to localized flexibility at the membrane-interacting protein face. PUFA CL acts as both a preferred substrate and a dynamic regulator by affecting the dynamics of the cyt c N70-I85 Ω loop, which covers the heme cavity.


Assuntos
Apoptose , Cardiolipinas/metabolismo , Lipidômica , Peroxidases/metabolismo , Animais , Membrana Celular/metabolismo , Citocromos c/metabolismo , Ácidos Graxos Insaturados/química , Heme/química , Cavalos , Espectroscopia de Ressonância Magnética , Miocárdio/metabolismo , Nanotecnologia , Oxigênio/química , Conformação Proteica , Domínios Proteicos , Dobramento de Proteína
13.
J Am Chem Soc ; 140(51): 17835-17839, 2018 12 26.
Artigo em Inglês | MEDLINE | ID: mdl-30525572

RESUMO

sn2-15-Hydroperoxy-eicasotetraenoyl-phosphatidylethanolamines ( sn2-15-HpETE-PE) generated by mammalian 15-lipoxygenase/phosphatidylethanolamine binding protein-1 (15-LO/PEBP1) complex is a death signal in a recently identified type of programmed cell demise, ferroptosis. How the enzymatic complex selects sn2-ETE-PE as the substrate among 1 of ∼100 total oxidizable membrane PUFA phospholipids is a central, yet unresolved question. To unearth the highly selective and specific mechanisms of catalytic competence, we used a combination of redox lipidomics, mutational and computational structural analysis to show they stem from (i) reactivity toward readily accessible hexagonally organized membrane sn2-ETE-PEs, (ii) relative preponderance of sn2-ETE-PE species vs other sn2-ETE-PLs, and (iii) allosteric modification of the enzyme in the complex with PEBP1. This emphasizes the role of enzymatic vs random stochastic free radical reactions in ferroptotic death signaling.


Assuntos
Araquidonato 15-Lipoxigenase/metabolismo , Morte Celular/fisiologia , Fosfatidiletanolaminas/metabolismo , Animais , Araquidonato 15-Lipoxigenase/química , Catálise , Linhagem Celular , Camundongos , Mutação , Oxirredução , Proteína de Ligação a Fosfatidiletanolamina/genética , Proteína de Ligação a Fosfatidiletanolamina/metabolismo , Fosfatidiletanolaminas/química , Especificidade por Substrato
14.
J Clin Invest ; 128(10): 4639-4653, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30198910

RESUMO

Ferroptosis is a death program executed via selective oxidation of arachidonic acid-phosphatidylethanolamines (AA-PE) by 15-lipoxygenases. In mammalian cells and tissues, ferroptosis has been pathogenically associated with brain, kidney, and liver injury/diseases. We discovered that a prokaryotic bacterium, Pseudomonas aeruginosa, that does not contain AA-PE can express lipoxygenase (pLoxA), oxidize host AA-PE to 15-hydroperoxy-AA-PE (15-HOO-AA-PE), and trigger ferroptosis in human bronchial epithelial cells. Induction of ferroptosis by clinical P. aeruginosa isolates from patients with persistent lower respiratory tract infections was dependent on the level and enzymatic activity of pLoxA. Redox phospholipidomics revealed elevated levels of oxidized AA-PE in airway tissues from patients with cystic fibrosis (CF) but not with emphysema or CF without P. aeruginosa. We believe that the evolutionarily conserved mechanism of pLoxA-driven ferroptosis may represent a potential therapeutic target against P. aeruginosa-associated diseases such as CF and persistent lower respiratory tract infections.


Assuntos
Apoptose , Fibrose Cística/metabolismo , Fosfatidiletanolaminas/metabolismo , Infecções por Pseudomonas/metabolismo , Pseudomonas aeruginosa/metabolismo , Mucosa Respiratória/metabolismo , Infecções Respiratórias/metabolismo , Linhagem Celular , Fibrose Cística/microbiologia , Fibrose Cística/patologia , Células Epiteliais/metabolismo , Células Epiteliais/microbiologia , Células Epiteliais/patologia , Humanos , Infecções por Pseudomonas/patologia , Pseudomonas aeruginosa/patogenicidade , Mucosa Respiratória/microbiologia , Mucosa Respiratória/fisiologia , Infecções Respiratórias/microbiologia , Infecções Respiratórias/patologia
15.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1863(10): 1354-1368, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29935382

RESUMO

Cardiolipin (CL) is a unique phospholipid localized almost exclusively within the mitochondrial membranes where it is synthesized. Newly synthesized CL undergoes acyl remodeling to produce CL species enriched with unsaturated acyl groups. Cld1 is the only identified CL-specific phospholipase in yeast and is required to initiate the CL remodeling pathway. In higher eukaryotes, peroxidation of CL, yielding CLOX, has been implicated in the cellular signaling events that initiate apoptosis. CLOX can undergo enzymatic hydrolysis, resulting in the release of lipid mediators with signaling properties. Our previous findings suggested that CLD1 expression is upregulated in response to oxidative stress, and that one of the physiological roles of CL remodeling is to remove peroxidized CL. To exploit the powerful yeast model to study functions of CLD1 in CL peroxidation, we expressed the H. brasiliensis Δ12-desaturase gene in yeast, which then synthesized poly unsaturated fatty acids(PUFAs) that are incorporated into CL species. Using LC-MS based redox phospholipidomics, we identified and quantified the molecular species of CL and other phospholipids in cld1Δ vs. WT cells. Loss of CLD1 led to a dramatic decrease in chronological lifespan, mitochondrial membrane potential, and respiratory capacity; it also resulted in increased levels of mono-hydroperoxy-CLs, particularly among the highly unsaturated CL species, including tetralinoleoyl-CL. In addition, purified Cld1 exhibited a higher affinity for CLOX, and treatment of cells with H2O2 increased CLD1 expression in the logarithmic growth phase. These data suggest that CLD1 expression is required to mitigate oxidative stress. The findings from this study contribute to our overall understanding of CL remodeling and its role in mitigating oxidative stress.


Assuntos
Cardiolipinas/metabolismo , Ácidos Graxos Dessaturases/genética , Ácidos Graxos Insaturados/metabolismo , Engenharia Genética/métodos , Fosfolipases/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Cardiolipinas/química , Cromatografia Líquida , Hevea/enzimologia , Hevea/genética , Hidrólise , Peroxidação de Lipídeos , Espectrometria de Massas , Estresse Oxidativo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo
16.
Antioxid Redox Signal ; 29(13): 1333-1358, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-28835115

RESUMO

SIGNIFICANCE: Oxygenated polyunsaturated lipids are known to play multi-functional roles as essential signals coordinating metabolism and physiology. Among them are well-studied eicosanoids and docosanoids that are generated via phospholipase A2 hydrolysis of membrane phospholipids and subsequent oxygenation of free polyunsaturated fatty acids (PUFA) by cyclooxygenases and lipoxygenases. Recent Advances: There is an emerging understanding that oxygenated PUFA-phospholipids also represent a rich signaling language with yet-to-be-deciphered details of the execution machinery-oxygenating enzymes, regulators, and receptors. Both free and esterified oxygenated PUFA signals are generated in cells, and their cross-talk and inter-conversion through the de-acylation/re-acylation reactions is not sufficiently explored. CRITICAL ISSUES: Here, we review recent data related to oxygenated phospholipids as important damage signals that trigger programmed cell death pathways to eliminate irreparably injured cells and preserve the health of multicellular environments. We discuss the mechanisms underlying the trans-membrane redistribution and generation of oxygenated cardiolipins in mitochondria by cytochrome c as pro-apoptotic signals. We also consider the role of oxygenated phosphatidylethanolamines as proximate pro-ferroptotic signals. FUTURE DIRECTIONS: We highlight the importance of sequential processes of phospholipid oxygenation and signaling in disease contexts as opportunities to use their regulatory mechanisms for the identification of new therapeutic targets.


Assuntos
Oxigênio/metabolismo , Fosfolipídeos/metabolismo , Transdução de Sinais , Animais , Diferenciação Celular , Humanos , Oxirredução
17.
Nat Commun ; 8(1): 2122, 2017 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-29242535

RESUMO

Cross-presentation is a critical function of dendritic cells (DCs) required for induction of antitumor immune responses and success of cancer immunotherapy. It is established that tumor-associated DCs are defective in their ability to cross-present antigens. However, the mechanisms driving these defects are still unknown. We find that impaired cross-presentation in DCs is largely associated with defect in trafficking of peptide-MHC class I (pMHC) complexes to the cell surface. DCs in tumor-bearing hosts accumulate lipid bodies (LB) containing electrophilic oxidatively truncated (ox-tr) lipids. These ox-tr-LB, but not LB present in control DCs, covalently bind to chaperone heat shock protein 70. This interaction prevents the translocation of pMHC to cell surface by causing the accumulation of pMHC inside late endosomes/lysosomes. As a result, tumor-associated DCs are no longer able to stimulate adequate CD8 T cells responses. In conclusion, this study demonstrates a mechanism regulating cross-presentation in cancer and suggests potential therapeutic avenues.


Assuntos
Antígenos/imunologia , Apresentação Cruzada/imunologia , Células Dendríticas/imunologia , Gotículas Lipídicas/imunologia , Lipídeos/imunologia , Neoplasias/imunologia , Animais , Apresentação do Antígeno/imunologia , Linhagem Celular Tumoral , Células Dendríticas/metabolismo , Endossomos/imunologia , Endossomos/metabolismo , Feminino , Proteínas de Choque Térmico HSP70/imunologia , Proteínas de Choque Térmico HSP70/metabolismo , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Gotículas Lipídicas/metabolismo , Lisossomos/imunologia , Lisossomos/metabolismo , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neoplasias/metabolismo , Neoplasias/patologia , Ligação Proteica
18.
Cell ; 171(3): 628-641.e26, 2017 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-29053969

RESUMO

Ferroptosis is a form of programmed cell death that is pathogenic to several acute and chronic diseases and executed via oxygenation of polyunsaturated phosphatidylethanolamines (PE) by 15-lipoxygenases (15-LO) that normally use free polyunsaturated fatty acids as substrates. Mechanisms of the altered 15-LO substrate specificity are enigmatic. We sought a common ferroptosis regulator for 15LO. We discovered that PEBP1, a scaffold protein inhibitor of protein kinase cascades, complexes with two 15LO isoforms, 15LO1 and 15LO2, and changes their substrate competence to generate hydroperoxy-PE. Inadequate reduction of hydroperoxy-PE due to insufficiency or dysfunction of a selenoperoxidase, GPX4, leads to ferroptosis. We demonstrated the importance of PEBP1-dependent regulatory mechanisms of ferroptotic death in airway epithelial cells in asthma, kidney epithelial cells in renal failure, and cortical and hippocampal neurons in brain trauma. As master regulators of ferroptotic cell death with profound implications for human disease, PEBP1/15LO complexes represent a new target for drug discovery.


Assuntos
Lesão Renal Aguda/patologia , Asma/patologia , Lesões Encefálicas Traumáticas/patologia , Morte Celular , Proteína de Ligação a Fosfatidiletanolamina/metabolismo , Lesão Renal Aguda/metabolismo , Animais , Apoptose , Asma/metabolismo , Lesões Encefálicas Traumáticas/metabolismo , Morte Celular/efeitos dos fármacos , Linhagem Celular , Humanos , Isoenzimas/metabolismo , Lipoxigenase/química , Lipoxigenase/metabolismo , Camundongos , Modelos Moleculares , Oxazolidinonas/farmacologia , Oxirredução , Proteína de Ligação a Fosfatidiletanolamina/química
19.
ACS Chem Biol ; 12(1): 265-281, 2017 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-27982579

RESUMO

Cardioipins (CLs) are unique tetra-acylated phospholipids of mitochondria and define the bioenergetics and regulatory functions of these organelles. An unresolved paradox is the high uniformity of CL molecular species (tetra-linoleoyl-CL) in the heart, liver, and skeletal muscles-in contrast to their high diversification in the brain. Here, we combined liquid chromatography-mass-spectrometry-based phospholipidomics with genetic and nutritional manipulations to explore CLs' biosynthetic vs postsynthetic remodeling processes in S. cerevisiae yeast cells. By applying the differential phospholipidomics analysis, we evaluated the contribution of Cld1 (CL-specific phospholipase A) and Taz1 (acyl-transferase) as the major regulatory mechanisms of the remodeling process. We further established that nutritional "pressure" by high levels of free fatty acids triggered a massive synthesis of homoacylated molecular species in all classes of phospholipids, resulting in the preponderance of the respective homoacylated CLs. We found that changes in molecular speciation of CLs induced by exogenous C18-fatty acids (C18:1 and C18:2) in wild-type (wt) cells did not occur in any of the remodeling mutant cells, including cld1Δ, taz1Δ, and cld1Δtaz1Δ. Interestingly, molecular speciation of CLs in wt and double mutant cells cld1Δtaz1Δ was markedly different. Given that the bioenergetics functions are preserved in the double mutant, this suggests that the accumulated MLCL-rather than the changed CL speciation-are the likely major contributors to the mitochondrial dysfunction in taz1Δ mutant cells (also characteristic of Barth syndrome). Biochemical studies of Cld1 specificity and computer modeling confirmed the hydrolytic selectivity of the enzyme toward C16-CL substrates and the preservation of C18:1-containing CL species.


Assuntos
Cardiolipinas/metabolismo , Saccharomyces cerevisiae/metabolismo , Acilação , Aciltransferases/metabolismo , Cardiolipinas/biossíntese , Ácidos Graxos/metabolismo , Hidrolases/química , Mitocôndrias/metabolismo , Simulação de Acoplamento Molecular , Estrutura Molecular , Mycobacterium tuberculosis , Fosfolipases/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Especificidade por Substrato
20.
Nat Chem Biol ; 13(1): 81-90, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27842066

RESUMO

Enigmatic lipid peroxidation products have been claimed as the proximate executioners of ferroptosis-a specialized death program triggered by insufficiency of glutathione peroxidase 4 (GPX4). Using quantitative redox lipidomics, reverse genetics, bioinformatics and systems biology, we discovered that ferroptosis involves a highly organized oxygenation center, wherein oxidation in endoplasmic-reticulum-associated compartments occurs on only one class of phospholipids (phosphatidylethanolamines (PEs)) and is specific toward two fatty acyls-arachidonoyl (AA) and adrenoyl (AdA). Suppression of AA or AdA esterification into PE by genetic or pharmacological inhibition of acyl-CoA synthase 4 (ACSL4) acts as a specific antiferroptotic rescue pathway. Lipoxygenase (LOX) generates doubly and triply-oxygenated (15-hydroperoxy)-diacylated PE species, which act as death signals, and tocopherols and tocotrienols (vitamin E) suppress LOX and protect against ferroptosis, suggesting a homeostatic physiological role for vitamin E. This oxidative PE death pathway may also represent a target for drug discovery.


Assuntos
Ácido Araquidônico/metabolismo , Ácidos Graxos Insaturados/metabolismo , Fosfolipídeos/metabolismo , Animais , Ácido Araquidônico/antagonistas & inibidores , Morte Celular/efeitos dos fármacos , Linhagem Celular , Coenzima A Ligases/antagonistas & inibidores , Coenzima A Ligases/deficiência , Coenzima A Ligases/metabolismo , Ácidos Graxos Insaturados/antagonistas & inibidores , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA