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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.
Cell Death Dis ; 11(10): 922, 2020 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-33110056

RESUMO

Lipid peroxidation (LPO) drives ferroptosis execution. However, LPO has been shown to contribute also to other modes of regulated cell death (RCD). To clarify the role of LPO in different modes of RCD, we studied in a comprehensive approach the differential involvement of reactive oxygen species (ROS), phospholipid peroxidation products, and lipid ROS flux in the major prototype modes of RCD viz. apoptosis, necroptosis, ferroptosis, and pyroptosis. LC-MS oxidative lipidomics revealed robust peroxidation of three classes of phospholipids during ferroptosis with quantitative predominance of phosphatidylethanolamine species. Incomparably lower amounts of phospholipid peroxidation products were found in any of the other modes of RCD. Nonetheless, a strong increase in lipid ROS levels was detected in non-canonical pyroptosis, but only during cell membrane rupture. In contrast to ferroptosis, lipid ROS apparently was not involved in non-canonical pyroptosis execution nor in the release of IL-1ß and IL-18, while clear dependency on CASP11 and GSDMD was observed. Our data demonstrate that ferroptosis is the only mode of RCD that depends on excessive phospholipid peroxidation for its cytotoxicity. In addition, our results also highlight the importance of performing kinetics and using different methods to monitor the occurrence of LPO. This should open the discussion on the implication of particular LPO events in relation to different modes of RCD.

6.
J Clin Invest ; 2020 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-32941182

RESUMO

Macrophages are main effectors of heme metabolism, increasing transiently in the liver during heightened disposal of damaged or senescent red blood cells (sRBC). Macrophages are also essential in defense against microbial threats, but pathologic states of heme excess may be immunosuppressive. Herein, we uncovered a mechanism whereby an acute rise in sRBC disposal by macrophages led to an immunosuppressive phenotype following intrapulmonary Klebsiella pneumoniae infection characterized by increased extrapulmonary bacterial proliferation and reduced survival from sepsis in mice. The impaired immunity to K. pneumoniae during heightened sRBC disposal was independent of iron acquisition by bacterial siderophores, as K. pneumoniae mutant lacking siderophore function recapitulated findings observed with wildtype strain. Rather, sRBC disposal induced a liver transcriptomic profile notable for suppression of Stat1 and interferon-related responses during K. pneumoniae sepsis. Excess heme handling by macrophages recapitulated STAT1 suppression during infection that required synergistic NRF1 and NRF2 activation but was independent of heme oxygenase-1 induction. Whereas iron was dispensable, the porphyrin moiety of heme was sufficient to mediate suppression of STAT1-dependent responses in human and mouse macrophages and promoted liver dissemination of K. pneumoniae in vivo. Thus, cellular heme metabolism dysfunction negatively regulates the STAT1 pathway with implications in severe infection.

7.
J Biol Chem ; 295(38): 13393-13406, 2020 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-32732285

RESUMO

Lysocardiolipin acyltransferase (LYCAT), a cardiolipin (CL)-remodeling enzyme, is crucial for maintaining normal mitochondrial function and vascular development. Despite the well-characterized role for LYCAT in the regulation of mitochondrial dynamics, its involvement in lung cancer, if any, remains incompletely understood. In this study, in silico analysis of TCGA lung cancer data sets revealed a significant increase in LYCAT expression, which was later corroborated in human lung cancer tissues and immortalized lung cancer cell lines via indirect immunofluorescence and immunoblotting, respectively. Stable knockdown of LYCAT in NSCLC cell lines not only reduced CL and increased monolyso-CL levels but also reduced in vivo tumor growth, as determined by xenograft studies in athymic nude mice. Furthermore, blocking LYCAT activity using a LYCAT mimetic peptide attenuated cell migration, suggesting a novel role for LYCAT activity in promoting NSCLC. Mechanistically, the pro-proliferative effects of LYCAT were mediated by an increase in mitochondrial fusion and a G1/S cell cycle transition, both of which are linked to increased cell proliferation. Taken together, these results demonstrate a novel role for LYCAT in promoting NSCLC and suggest that targeting LYCAT expression or activity in NSCLC may provide new avenues for the therapeutic treatment of lung cancer.

8.
Proc Natl Acad Sci U S A ; 117(25): 14376-14385, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32513718

RESUMO

Temporally harmonized elimination of damaged or unnecessary organelles and cells is a prerequisite of health. Under Type 2 inflammatory conditions, human airway epithelial cells (HAECs) generate proferroptotic hydroperoxy-arachidonoyl-phosphatidylethanolamines (HpETE-PEs) as proximate death signals. Production of 15-HpETE-PE depends on activation of 15-lipoxygenase-1 (15LO1) in complex with PE-binding protein-1 (PEBP1). We hypothesized that cellular membrane damage induced by these proferroptotic phospholipids triggers compensatory prosurvival pathways, and in particular autophagic pathways, to prevent cell elimination through programmed death. We discovered that PEBP1 is pivotal to driving dynamic interactions with both proferroptotic 15LO1 and the autophagic protein microtubule-associated light chain-3 (LC3). Further, the 15LO1-PEBP1-generated ferroptotic phospholipid, 15-HpETE-PE, promoted LC3-I lipidation to stimulate autophagy. This concurrent activation of autophagy protects cells from ferroptotic death and release of mitochondrial DNA. Similar findings are observed in Type 2 Hi asthma, where high levels of both 15LO1-PEBP1 and LC3-II are seen in HAECs, in association with low bronchoalveolar lavage fluid mitochondrial DNA and more severe disease. The concomitant activation of ferroptosis and autophagy by 15LO1-PEBP1 complexes and their hydroperoxy-phospholipids reveals a pathobiologic pathway relevant to asthma and amenable to therapeutic targeting.


Assuntos
Araquidonato 15-Lipoxigenase/metabolismo , Asma/imunologia , Autofagia/imunologia , Células Epiteliais/patologia , Ferroptose/imunologia , Proteína de Ligação a Fosfatidiletanolamina/metabolismo , Adulto , Animais , Asma/diagnóstico , Asma/patologia , Líquido da Lavagem Broncoalveolar/citologia , Linhagem Celular , Sobrevivência Celular/imunologia , Células Epiteliais/imunologia , Feminino , Técnicas de Inativação de Genes , Humanos , Ácidos Hidroxieicosatetraenoicos/imunologia , Ácidos Hidroxieicosatetraenoicos/metabolismo , Interleucina-13/imunologia , Interleucina-13/metabolismo , Masculino , Camundongos , Proteínas Associadas aos Microtúbulos/metabolismo , Simulação de Dinâmica Molecular , Proteína de Ligação a Fosfatidiletanolamina/genética , Fosfatidiletanolaminas/imunologia , Fosfatidiletanolaminas/metabolismo , Cultura Primária de Células , Ligação Proteica/imunologia , Índice de Gravidade de Doença
9.
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.

10.
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.

11.
Cell Chem Biol ; 27(4): 387-408, 2020 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-32275865

RESUMO

Redox balance is essential for normal brain, hence dis-coordinated oxidative reactions leading to neuronal death, including programs of regulated death, are commonly viewed as an inevitable pathogenic penalty for acute neuro-injury and neurodegenerative diseases. Ferroptosis is one of these programs triggered by dyshomeostasis of three metabolic pillars: iron, thiols, and polyunsaturated phospholipids. This review focuses on: (1) lipid peroxidation (LPO) as the major instrument of cell demise, (2) iron as its catalytic mechanism, and (3) thiols as regulators of pro-ferroptotic signals, hydroperoxy lipids. Given the central role of LPO, we discuss the engagement of selective and specific enzymatic pathways versus random free radical chemical reactions in the context of the phospholipid substrates, their biosynthesis, intracellular location, and related oxygenating machinery as participants in ferroptotic cascades. These concepts are discussed in the light of emerging neuro-therapeutic approaches controlling intracellular production of pro-ferroptotic phospholipid signals and their non-cell-autonomous spreading, leading to ferroptosis-associated necroinflammation.

12.
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
13.
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
14.
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
15.
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
16.
J Clin Invest ; 129(6): 2293-2304, 2019 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-30830879

RESUMO

Non-apoptotic forms of cell death can trigger sterile inflammation through the release of danger-associated molecular patterns, which are recognized by innate immune receptors. However, despite years of investigation the mechanisms which initiate inflammatory responses after heart transplantation remain elusive. Here, we demonstrate that ferrostatin-1 (Fer-1), a specific inhibitor of ferroptosis, decreases the level of pro-ferroptotic hydroperoxy-arachidonoyl-phosphatidylethanolamine, reduces cardiomyocyte cell death and blocks neutrophil recruitment following heart transplantation. Inhibition of necroptosis had no effect on neutrophil trafficking in cardiac grafts. We extend these observations to a model of coronary artery ligation-induced myocardial ischemia reperfusion injury where inhibition of ferroptosis resulted in reduced infarct size, improved left ventricular systolic function, and reduced left ventricular remodeling. Using intravital imaging of cardiac transplants, we uncover that ferroptosis orchestrates neutrophil recruitment to injured myocardium by promoting adhesion of neutrophils to coronary vascular endothelial cells through a TLR4/TRIF/type I IFN signaling pathway. Thus, we have discovered that inflammatory responses after cardiac transplantation are initiated through ferroptotic cell death and TLR4/Trif-dependent signaling in graft endothelial cells. These findings provide a platform for the development of therapeutic strategies for heart transplant recipients and patients, who are vulnerable to ischemia reperfusion injury following restoration of coronary blood flow.


Assuntos
Proteínas Adaptadoras de Transporte Vesicular/imunologia , Ferroptose/imunologia , Transplante de Coração , Traumatismo por Reperfusão Miocárdica/imunologia , Miocárdio/imunologia , Infiltração de Neutrófilos , Neutrófilos/imunologia , Transdução de Sinais/imunologia , Receptor 4 Toll-Like/imunologia , Proteínas Adaptadoras de Transporte Vesicular/genética , Animais , Cicloexilaminas/farmacologia , Ferroptose/efeitos dos fármacos , Ferroptose/genética , Inflamação/tratamento farmacológico , Inflamação/genética , Inflamação/imunologia , Inflamação/patologia , Camundongos , Camundongos Knockout , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Traumatismo por Reperfusão Miocárdica/genética , Traumatismo por Reperfusão Miocárdica/patologia , Miocárdio/patologia , Neutrófilos/patologia , Fenilenodiaminas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Receptor 4 Toll-Like/genética , Função Ventricular Esquerda/efeitos dos fármacos , Função Ventricular Esquerda/genética , Função Ventricular Esquerda/imunologia
17.
Proc Natl Acad Sci U S A ; 116(2): 650-659, 2019 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-30584104

RESUMO

Neuritic retraction in the absence of overt neuronal death is a shared feature of normal aging and neurodegenerative disorders, but the intracellular mechanisms modulating this process are not understood. We propose that cumulative distal mitochondrial protein damage results in impaired protein import, leading to mitochondrial dysfunction and focal activation of the canonical apoptosis pathway in neurites. This is a controlled process that may not lead to neuronal death and, thus, we term this phenomenon "neuritosis." Consistent with our hypothesis, we show that in primary cerebrocortical neurons, mitochondrial distance from the soma correlates with increased mitochondrial protein damage, PINK1 accumulation, reactive oxygen species production, and decreased mitochondrial membrane potential and depolarization threshold. Furthermore, we demonstrate that the distance-dependent mitochondrial membrane potential gradient exists in vivo in mice. We demonstrate that impaired distal mitochondria have a lower threshold for focal/nonlethal neuritic caspase-3 activation in normal neurons that is exacerbated in aging, stress, and neurodegenerative conditions, thus delineating a fundamental mechanistic underpinning for synaptic vulnerability.


Assuntos
Apoptose , Potencial da Membrana Mitocondrial , Mitocôndrias/metabolismo , Neuritos/metabolismo , Doenças Neurodegenerativas/metabolismo , Animais , Caspase 3/genética , Caspase 3/metabolismo , Camundongos , Camundongos Transgênicos , Mitocôndrias/genética , Mitocôndrias/patologia , Neuritos/patologia , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/patologia , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo
18.
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
19.
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
20.
Biochim Biophys Acta Mol Basis Dis ; 1864(10): 3353-3367, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30055293

RESUMO

Cardiolipin (CL) is a key mitochondrial phospholipid essential for mitochondrial energy production. CL is remodeled from monolysocardiolipin (MLCL) by the enzyme tafazzin (TAZ). Loss-of-function mutations in the gene which encodes TAZ results in a rare X-linked disorder called Barth Syndrome (BTHS). The mutated TAZ is unable to maintain the physiological CL:MLCL ratio, thus reducing CL levels and affecting mitochondrial function. BTHS is best known as a cardiac disease, but has been acknowledged as a multi-syndrome disorder, including cognitive deficits. Since reduced CL levels has also been reported in numerous neurodegenerative disorders, we examined how TAZ-deficiency impacts cognitive abilities, brain mitochondrial respiration and the function of hippocampal neurons and glia in TAZ knockdown (TAZ kd) mice. We have identified for the first time the profile of changes that occur in brain phospholipid content and composition of TAZ kd mice. The brain of TAZ kd mice exhibited reduced TAZ protein expression, reduced total CL levels and a 19-fold accumulation of MLCL compared to wild-type littermate controls. TAZ kd brain exhibited a markedly distinct profile of CL and MLCL molecular species. In mitochondria, the activity of complex I was significantly elevated in the monomeric and supercomplex forms with TAZ-deficiency. This corresponded with elevated mitochondrial state I respiration and attenuated spare capacity. Furthermore, the production of reactive oxygen species was significantly elevated in TAZ kd brain mitochondria. While motor function remained normal in TAZ kd mice, they showed significant memory deficiency based on novel object recognition test. These results correlated with reduced synaptophysin protein levels and derangement of the neuronal CA1 layer in hippocampus. Finally, TAZ kd mice had elevated activation of brain immune cells, microglia compared to littermate controls. Collectively, our findings demonstrate that TAZ-mediated remodeling of CL contributes significantly to the expansive distribution of CL molecular species in the brain, plays a key role in mitochondria respiratory activity, maintains normal cognitive function, and identifies the hippocampus as a potential therapeutic target for BTHS.


Assuntos
Cardiolipinas/metabolismo , Disfunção Cognitiva/genética , Hipocampo/metabolismo , Fatores de Transcrição/genética , Animais , Disfunção Cognitiva/metabolismo , Modelos Animais de Doenças , Técnicas de Silenciamento de Genes , Lisofosfolipídeos , Camundongos , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Sinaptofisina/metabolismo , Fatores de Transcrição/metabolismo
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