RESUMO
Phosphatidic acid (PA) and reactive oxygen species (ROS) are crucial cellular messengers mediating diverse signaling processes in metazoans and plants. How PA homeostasis is tightly regulated and intertwined with ROS signaling upon immune elicitation remains elusive. We report here that Arabidopsis diacylglycerol kinase 5 (DGK5) regulates plant pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). The pattern recognition receptor (PRR)-associated kinase BIK1 phosphorylates DGK5 at Ser-506, leading to a rapid PA burst and activation of plant immunity, whereas PRR-activated intracellular MPK4 phosphorylates DGK5 at Thr-446, which subsequently suppresses DGK5 activity and PA production, resulting in attenuated plant immunity. PA binds and stabilizes the NADPH oxidase RESPIRATORY BURST OXIDASE HOMOLOG D (RBOHD), regulating ROS production in plant PTI and ETI, and their potentiation. Our data indicate that distinct phosphorylation of DGK5 by PRR-activated BIK1 and MPK4 balances the homeostasis of cellular PA burst that regulates ROS generation in coordinating two branches of plant immunity.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Diacilglicerol Quinase , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Diacilglicerol Quinase/metabolismo , NADPH Oxidases/metabolismo , Ácidos Fosfatídicos/metabolismo , Fosforilação , Imunidade Vegetal , Proteínas Serina-Treonina Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Receptores de Reconhecimento de Padrão/metabolismoRESUMO
NLRs constitute a large, highly conserved family of cytosolic pattern recognition receptors that are central to health and disease, making them key therapeutic targets. NLRC5 is an enigmatic NLR with mutations associated with inflammatory and infectious diseases, but little is known about its function as an innate immune sensor and cell death regulator. Therefore, we screened for NLRC5's role in response to infections, PAMPs, DAMPs, and cytokines. We identified that NLRC5 acts as an innate immune sensor to drive inflammatory cell death, PANoptosis, in response to specific ligands, including PAMP/heme and heme/cytokine combinations. NLRC5 interacted with NLRP12 and PANoptosome components to form a cell death complex, suggesting an NLR network forms similar to those in plants. Mechanistically, TLR signaling and NAD+ levels regulated NLRC5 expression and ROS production to control cell death. Furthermore, NLRC5-deficient mice were protected in hemolytic and inflammatory models, suggesting that NLRC5 could be a potential therapeutic target.
Assuntos
Inflamação , Peptídeos e Proteínas de Sinalização Intracelular , NAD , Animais , Camundongos , Inflamação/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , NAD/metabolismo , Humanos , Imunidade Inata , Camundongos Endogâmicos C57BL , Espécies Reativas de Oxigênio/metabolismo , Camundongos Knockout , Transdução de Sinais , Células HEK293 , Inflamassomos/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas Reguladoras de Apoptose/genética , Receptores Toll-Like/metabolismo , Masculino , Citocinas/metabolismo , Proteínas de Ligação ao CálcioRESUMO
Multiple anticancer drugs have been proposed to cause cell death, in part, by increasing the steady-state levels of cellular reactive oxygen species (ROS). However, for most of these drugs, exactly how the resultant ROS function and are sensed is poorly understood. It remains unclear which proteins the ROS modify and their roles in drug sensitivity/resistance. To answer these questions, we examined 11 anticancer drugs with an integrated proteogenomic approach identifying not only many unique targets but also shared ones-including ribosomal components, suggesting common mechanisms by which drugs regulate translation. We focus on CHK1 that we find is a nuclear H2O2 sensor that launches a cellular program to dampen ROS. CHK1 phosphorylates the mitochondrial DNA-binding protein SSBP1 to prevent its mitochondrial localization, which in turn decreases nuclear H2O2. Our results reveal a druggable nucleus-to-mitochondria ROS-sensing pathway-required to resolve nuclear H2O2 accumulation and mediate resistance to platinum-based agents in ovarian cancers.
Assuntos
Antineoplásicos , Espécies Reativas de Oxigênio , Antineoplásicos/farmacologia , Antineoplásicos/metabolismo , Peróxido de Hidrogênio/metabolismo , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Núcleo Celular/metabolismo , HumanosRESUMO
Ferroptosis, a form of cell death driven by iron-dependent lipid peroxidation, was identified as a distinct phenomenon and named a decade ago. Ferroptosis has been implicated in a broad set of biological contexts, from development to aging, immunity, and cancer. This review describes key regulators of this form of cell death within a framework of metabolism, ROS biology, and iron biology. Key concepts and major unanswered questions in the ferroptosis field are highlighted. The next decade promises to yield further breakthroughs in the mechanisms governing ferroptosis and additional ways of harnessing ferroptosis for therapeutic benefit.
Assuntos
Ferroptose , Morte Celular , Ferro/metabolismo , Peroxidação de Lipídeos , Espécies Reativas de Oxigênio/metabolismoRESUMO
Although mutations in mitochondrial-associated genes are linked to inflammation and susceptibility to infection, their mechanistic contributions to immune outcomes remain ill-defined. We discovered that the disease-associated gain-of-function allele Lrrk2G2019S (leucine-rich repeat kinase 2) perturbs mitochondrial homeostasis and reprograms cell death pathways in macrophages. When the inflammasome is activated in Lrrk2G2019S macrophages, elevated mitochondrial ROS (mtROS) directs association of the pore-forming protein gasdermin D (GSDMD) to mitochondrial membranes. Mitochondrial GSDMD pore formation then releases mtROS, promoting a switch to RIPK1/RIPK3/MLKL-dependent necroptosis. Consistent with enhanced necroptosis, infection of Lrrk2G2019S mice with Mycobacterium tuberculosis elicits hyperinflammation and severe immunopathology. Our findings suggest a pivotal role for GSDMD as an executer of multiple cell death pathways and demonstrate that mitochondrial dysfunction can direct immune outcomes via cell death modality switching. This work provides insights into how LRRK2 mutations manifest or exacerbate human diseases and identifies GSDMD-dependent necroptosis as a potential target to limit Lrrk2G2019S-mediated immunopathology.
Assuntos
Mitocôndrias , Necroptose , Proteínas de Ligação a Fosfato/metabolismo , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Animais , Humanos , Inflamassomos , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina , Macrófagos , Camundongos , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismoRESUMO
Metabolic programming is important for B cell fate, but the bioenergetic requirement for regulatory B (Breg) cell differentiation and function is unknown. Here we show that Breg cell differentiation, unlike non-Breg cells, relies on mitochondrial electron transport and homeostatic levels of reactive oxygen species (ROS). Single-cell RNA sequencing analysis revealed that TXN, encoding the metabolic redox protein thioredoxin (Trx), is highly expressed by Breg cells, unlike Trx inhibitor TXNIP which was downregulated. Pharmacological inhibition or gene silencing of TXN resulted in mitochondrial membrane depolarization and increased ROS levels, selectively suppressing Breg cell differentiation and function while favoring pro-inflammatory B cell differentiation. Patients with systemic lupus erythematosus (SLE), characterized by Breg cell deficiencies, present with B cell mitochondrial membrane depolarization, elevated ROS and fewer Trx+ B cells. Exogenous Trx stimulation restored Breg cells and mitochondrial membrane polarization in SLE B cells to healthy B cell levels, indicating Trx insufficiency underlies Breg cell impairment in patients with SLE.
Assuntos
Proteínas de Transporte , Diferenciação Celular , Lúpus Eritematoso Sistêmico , Mitocôndrias , Espécies Reativas de Oxigênio , Tiorredoxinas , Tiorredoxinas/metabolismo , Tiorredoxinas/genética , Humanos , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Mitocôndrias/metabolismo , Feminino , Animais , Camundongos , Potencial da Membrana Mitocondrial , Masculino , Adulto , OxirreduçãoRESUMO
Plant immunity is activated upon pathogen perception and often affects growth and yield when it is constitutively active. How plants fine-tune immune homeostasis in their natural habitats remains elusive. Here, we discover a conserved immune suppression network in cereals that orchestrates immune homeostasis, centering on a Ca2+-sensor, RESISTANCE OF RICE TO DISEASES1 (ROD1). ROD1 promotes reactive oxygen species (ROS) scavenging by stimulating catalase activity, and its protein stability is regulated by ubiquitination. ROD1 disruption confers resistance to multiple pathogens, whereas a natural ROD1 allele prevalent in indica rice with agroecology-specific distribution enhances resistance without yield penalty. The fungal effector AvrPiz-t structurally mimics ROD1 and activates the same ROS-scavenging cascade to suppress host immunity and promote virulence. We thus reveal a molecular framework adopted by both host and pathogen that integrates Ca2+ sensing and ROS homeostasis to suppress plant immunity, suggesting a principle for breeding disease-resistant, high-yield crops.
Assuntos
Cálcio/metabolismo , Sequestradores de Radicais Livres/metabolismo , Proteínas Fúngicas/metabolismo , Oryza/imunologia , Imunidade Vegetal , Proteínas de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Sistemas CRISPR-Cas/genética , Membrana Celular/metabolismo , Resistência à Doença/genética , Modelos Biológicos , Oryza/genética , Doenças das Plantas/imunologia , Proteínas de Plantas/genética , Ligação Proteica , Estabilidade Proteica , Reprodução , Especificidade da Espécie , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação , Zea mays/imunologiaRESUMO
Nucleotide-binding, leucine-rich repeat receptors (NLRs) are major immune receptors in plants and animals. Upon activation, the Arabidopsis NLR protein ZAR1 forms a pentameric resistosome in vitro and triggers immune responses and cell death in plants. In this study, we employed single-molecule imaging to show that the activated ZAR1 protein can form pentameric complexes in the plasma membrane. The ZAR1 resistosome displayed ion channel activity in Xenopus oocytes in a manner dependent on a conserved acidic residue Glu11 situated in the channel pore. Pre-assembled ZAR1 resistosome was readily incorporated into planar lipid-bilayers and displayed calcium-permeable cation-selective channel activity. Furthermore, we show that activation of ZAR1 in the plant cell led to Glu11-dependent Ca2+ influx, perturbation of subcellular structures, production of reactive oxygen species, and cell death. The results thus support that the ZAR1 resistosome acts as a calcium-permeable cation channel to trigger immunity and cell death.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/imunologia , Arabidopsis/metabolismo , Cálcio/metabolismo , Proteínas de Transporte/metabolismo , Resistência à Doença/imunologia , Imunidade Vegetal , Transdução de Sinais , Animais , Morte Celular , Membrana Celular/metabolismo , Permeabilidade da Membrana Celular , Ácido Glutâmico/metabolismo , Bicamadas Lipídicas/metabolismo , Oócitos/metabolismo , Células Vegetais/metabolismo , Multimerização Proteica , Protoplastos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Imagem Individual de Molécula , Vacúolos/metabolismo , XenopusRESUMO
Microglia are the CNS resident immune cells that react to misfolded proteins through pattern recognition receptor ligation and activation of inflammatory pathways. Here, we studied how microglia handle and cope with α-synuclein (α-syn) fibrils and their clearance. We found that microglia exposed to α-syn establish a cellular network through the formation of F-actin-dependent intercellular connections, which transfer α-syn from overloaded microglia to neighboring naive microglia where the α-syn cargo got rapidly and effectively degraded. Lowering the α-syn burden attenuated the inflammatory profile of microglia and improved their survival. This degradation strategy was compromised in cells carrying the LRRK2 G2019S mutation. We confirmed the intercellular transfer of α-syn assemblies in microglia using organotypic slice cultures, 2-photon microscopy, and neuropathology of patients. Together, these data identify a mechanism by which microglia create an "on-demand" functional network in order to improve pathogenic α-syn clearance.
Assuntos
Estruturas da Membrana Celular/metabolismo , Microglia/metabolismo , Proteólise , alfa-Sinucleína/metabolismo , Actinas/metabolismo , Idoso , Idoso de 80 Anos ou mais , Animais , Apoptose , Citoesqueleto/metabolismo , Regulação para Baixo , Feminino , Humanos , Inflamação/genética , Inflamação/patologia , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Microglia/patologia , Microglia/ultraestrutura , Mitocôndrias/metabolismo , Nanotubos , Agregados Proteicos , Espécies Reativas de Oxigênio/metabolismo , Transcriptoma/genéticaRESUMO
Although oxidative phosphorylation is best known for producing ATP, it also yields reactive oxygen species (ROS) as invariant byproducts. Depletion of ROS below their physiological levels, a phenomenon known as reductive stress, impedes cellular signaling and has been linked to cancer, diabetes, and cardiomyopathy. Cells alleviate reductive stress by ubiquitylating and degrading the mitochondrial gatekeeper FNIP1, yet it is unknown how the responsible E3 ligase CUL2FEM1B can bind its target based on redox state and how this is adjusted to changing cellular environments. Here, we show that CUL2FEM1B relies on zinc as a molecular glue to selectively recruit reduced FNIP1 during reductive stress. FNIP1 ubiquitylation is gated by pseudosubstrate inhibitors of the BEX family, which prevent premature FNIP1 degradation to protect cells from unwarranted ROS accumulation. FEM1B gain-of-function mutation and BEX deletion elicit similar developmental syndromes, showing that the zinc-dependent reductive stress response must be tightly regulated to maintain cellular and organismal homeostasis.
Assuntos
Estresse Fisiológico , Aminoácidos/química , Animais , Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Feminino , Humanos , Íons , Camundongos , Proteínas Mutantes/metabolismo , Mutação/genética , Ligação Proteica/efeitos dos fármacos , Estabilidade Proteica/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Relação Estrutura-Atividade , Especificidade por Substrato/efeitos dos fármacos , Complexos Ubiquitina-Proteína Ligase/química , Complexos Ubiquitina-Proteína Ligase/metabolismo , Ubiquitinação/efeitos dos fármacos , Zinco/farmacologiaRESUMO
The process of pyroptosis is mediated by inflammasomes and a downstream effector known as gasdermin D (GSDMD). Upon cleavage by inflammasome-associated caspases, the N-terminal domain of GSDMD forms membrane pores that promote cytolysis. Numerous proteins promote GSDMD cleavage, but none are known to be required for pore formation after GSDMD cleavage. Herein, we report a forward genetic screen that identified the Ragulator-Rag complex as being necessary for GSDMD pore formation and pyroptosis in macrophages. Mechanistic analysis revealed that Ragulator-Rag is not required for GSDMD cleavage upon inflammasome activation but rather promotes GSDMD oligomerization in the plasma membrane. Defects in GSDMD oligomerization and pore formation can be rescued by mitochondrial poisons that stimulate reactive oxygen species (ROS) production, and ROS modulation impacts the ability of inflammasome pathways to promote pore formation downstream of GSDMD cleavage. These findings reveal an unexpected link between key regulators of immunity (inflammasome-GSDMD) and metabolism (Ragulator-Rag).
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Proteínas de Ligação a Fosfato/metabolismo , Multimerização Proteica , Piroptose , Transdução de Sinais , Aminoácidos/metabolismo , Animais , Moléculas de Adesão Celular Neuronais/metabolismo , Linhagem Celular , Testes Genéticos , Humanos , Inflamassomos/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/química , Macrófagos/metabolismo , Alvo Mecanístico do Complexo 2 de Rapamicina/metabolismo , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Fatores de Crescimento Neural/metabolismo , Proteínas de Ligação a Fosfato/química , Domínios Proteicos , RNA Guia de Cinetoplastídeos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Serina-Treonina Quinases TOR/metabolismoRESUMO
Mitochondrial diseases are clinically heterogeneous disorders caused by a wide spectrum of mutations in genes encoded by either the nuclear or the mitochondrial genome. Treatments for mitochondrial diseases are currently focused on symptomatic management rather than improving the biochemical defect caused by a particular mutation. This review focuses on the latest advances in the development of treatments for mitochondrial disease, both small molecules and gene therapies, as well as methods to prevent transmission of mitochondrial disease through the germline.
Assuntos
Mitocôndrias/genética , Doenças Mitocondriais/terapia , Animais , DNA Mitocondrial/genética , Terapia Genética , Genoma Mitocondrial/genética , Humanos , Mitocôndrias/patologia , Doenças Mitocondriais/genética , Mutação , NAD/metabolismo , Espécies Reativas de Oxigênio/metabolismoRESUMO
The view that sleep is essential for survival is supported by the ubiquity of this behavior, the apparent existence of sleep-like states in the earliest animals, and the fact that severe sleep loss can be lethal. The cause of this lethality is unknown. Here we show, using flies and mice, that sleep deprivation leads to accumulation of reactive oxygen species (ROS) and consequent oxidative stress, specifically in the gut. ROS are not just correlates of sleep deprivation but drivers of death: their neutralization prevents oxidative stress and allows flies to have a normal lifespan with little to no sleep. The rescue can be achieved with oral antioxidant compounds or with gut-targeted transgenic expression of antioxidant enzymes. We conclude that death upon severe sleep restriction can be caused by oxidative stress, that the gut is central in this process, and that survival without sleep is possible when ROS accumulation is prevented. VIDEO ABSTRACT.
Assuntos
Trato Gastrointestinal/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Privação do Sono/metabolismo , Sono/fisiologia , Animais , Antioxidantes/metabolismo , Drosophila , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Estresse Oxidativo/fisiologiaRESUMO
Metazoan organisms rely on conserved stress response pathways to alleviate adverse conditions and preserve cellular integrity. Stress responses are particularly important in stem cells that provide lifetime support for tissue formation and repair, but how these protective systems are integrated into developmental programs is poorly understood. Here we used myoblast differentiation to identify the E3 ligase CUL2FEM1B and its substrate FNIP1 as core components of the reductive stress response. Reductive stress, as caused by prolonged antioxidant signaling or mitochondrial inactivity, reverts the oxidation of invariant Cys residues in FNIP1 and allows CUL2FEM1B to recognize its target. The ensuing proteasomal degradation of FNIP1 restores mitochondrial activity to preserve redox homeostasis and stem cell integrity. The reductive stress response is therefore built around a ubiquitin-dependent rheostat that tunes mitochondrial activity to redox needs and implicates metabolic control in coordination of stress and developmental signaling.
Assuntos
Proteínas de Transporte/metabolismo , Estresse Oxidativo/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Antioxidantes/metabolismo , Proteínas de Transporte/genética , Diferenciação Celular , Células HEK293 , Homeostase , Humanos , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Mitocôndrias , Desenvolvimento Muscular/fisiologia , Mioblastos/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Transdução de Sinais , Ubiquitina-Proteína Ligases/metabolismo , UbiquitinaçãoRESUMO
Molecular mechanisms of ovarian aging and female age-related fertility decline remain unclear. We surveyed the single-cell transcriptomic landscape of ovaries from young and aged non-human primates (NHPs) and identified seven ovarian cell types with distinct gene-expression signatures, including oocyte and six types of ovarian somatic cells. In-depth dissection of gene-expression dynamics of oocytes revealed four subtypes at sequential and stepwise developmental stages. Further analysis of cell-type-specific aging-associated transcriptional changes uncovered the disturbance of antioxidant signaling specific to early-stage oocytes and granulosa cells, indicative of oxidative damage as a crucial factor in ovarian functional decline with age. Additionally, inactivated antioxidative pathways, increased reactive oxygen species, and apoptosis were observed in granulosa cells from aged women. This study provides a comprehensive understanding of the cell-type-specific mechanisms underlying primate ovarian aging at single-cell resolution, revealing new diagnostic biomarkers and potential therapeutic targets for age-related human ovarian disorders.
Assuntos
Envelhecimento/genética , Ovário/fisiologia , Análise de Célula Única/métodos , Transcriptoma , Idoso , Animais , Antioxidantes/metabolismo , Apoptose/fisiologia , Atlas como Assunto , Biomarcadores , Linhagem Celular Tumoral , Feminino , Células da Granulosa/metabolismo , Humanos , Macaca fascicularis , Oócitos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/fisiologiaRESUMO
Human cells are able to sense and adapt to variations in oxygen levels. Historically, much research in this field has focused on hypoxia-inducible factor (HIF) signaling and reactive oxygen species (ROS). Here, we perform genome-wide CRISPR growth screens at 21%, 5%, and 1% oxygen to systematically identify gene knockouts with relative fitness defects in high oxygen (213 genes) or low oxygen (109 genes), most without known connection to HIF or ROS. Knockouts of many mitochondrial pathways thought to be essential, including complex I and enzymes in Fe-S biosynthesis, grow relatively well at low oxygen and thus are buffered by hypoxia. In contrast, in certain cell types, knockout of lipid biosynthetic and peroxisomal genes causes fitness defects only in low oxygen. Our resource nominates genetic diseases whose severity may be modulated by oxygen and links hundreds of genes to oxygen homeostasis.
Assuntos
Metabolismo dos Lipídeos/genética , Mitocôndrias/genética , Oxigênio/metabolismo , Transcriptoma/genética , Hipóxia Celular , Testes Genéticos/métodos , Estudo de Associação Genômica Ampla/métodos , Células HEK293 , Humanos , Hipóxia/metabolismo , Células K562 , Metabolismo dos Lipídeos/fisiologia , Lipídeos/genética , Lipídeos/fisiologia , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/fisiologiaRESUMO
Cardiomyocytes are subjected to the intense mechanical stress and metabolic demands of the beating heart. It is unclear whether these cells, which are long-lived and rarely renew, manage to preserve homeostasis on their own. While analyzing macrophages lodged within the healthy myocardium, we discovered that they actively took up material, including mitochondria, derived from cardiomyocytes. Cardiomyocytes ejected dysfunctional mitochondria and other cargo in dedicated membranous particles reminiscent of neural exophers, through a process driven by the cardiomyocyte's autophagy machinery that was enhanced during cardiac stress. Depletion of cardiac macrophages or deficiency in the phagocytic receptor Mertk resulted in defective elimination of mitochondria from the myocardial tissue, activation of the inflammasome, impaired autophagy, accumulation of anomalous mitochondria in cardiomyocytes, metabolic alterations, and ventricular dysfunction. Thus, we identify an immune-parenchymal pair in the murine heart that enables transfer of unfit material to preserve metabolic stability and organ function. VIDEO ABSTRACT.
Assuntos
Macrófagos/metabolismo , Mitocôndrias/metabolismo , Miócitos Cardíacos/metabolismo , Idoso , Animais , Apoptose , Autofagia , Feminino , Coração/fisiologia , Homeostase , Humanos , Macrófagos/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Mitocôndrias/fisiologia , Infarto do Miocárdio/metabolismo , Miocárdio/metabolismo , Miócitos Cardíacos/fisiologia , Fagocitose/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , c-Mer Tirosina Quinase/metabolismoRESUMO
Metabolic reprogramming is a key feature of many cancers, but how and when it contributes to tumorigenesis remains unclear. Here we demonstrate that metabolic reprogramming induced by mitochondrial fusion can be rate-limiting for immortalization of tumor-initiating cells (TICs) and trigger their irreversible dedication to tumorigenesis. Using single-cell transcriptomics, we find that Drosophila brain tumors contain a rapidly dividing stem cell population defined by upregulation of oxidative phosphorylation (OxPhos). We combine targeted metabolomics and in vivo genetic screening to demonstrate that OxPhos is required for tumor cell immortalization but dispensable in neural stem cells (NSCs) giving rise to tumors. Employing an in vivo NADH/NAD+ sensor, we show that NSCs precisely increase OxPhos during immortalization. Blocking OxPhos or mitochondrial fusion stalls TICs in quiescence and prevents tumorigenesis through impaired NAD+ regeneration. Our work establishes a unique connection between cellular metabolism and immortalization of tumor-initiating cells.
Assuntos
Neoplasias Encefálicas/metabolismo , Carcinogênese/metabolismo , Transformação Celular Neoplásica/metabolismo , Dinâmica Mitocondrial , NAD/metabolismo , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neurais/metabolismo , Fosforilação Oxidativa , Animais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/patologia , Carcinogênese/genética , Carcinogênese/patologia , Transformação Celular Neoplásica/patologia , Ciclo do Ácido Cítrico/genética , Biologia Computacional , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Drosophila , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Glicólise/genética , Espectrometria de Massas , Metabolômica , Microscopia Eletrônica de Transmissão , Família Multigênica , Células-Tronco Neurais/patologia , Consumo de Oxigênio/genética , Interferência de RNA , Espécies Reativas de Oxigênio/metabolismo , Análise de Célula Única , Transcriptoma/genéticaRESUMO
The NLRP3 inflammasome is linked to sterile and pathogen-dependent inflammation, and its dysregulation underlies many chronic diseases. Mitochondria have been implicated as regulators of the NLRP3 inflammasome through several mechanisms including generation of mitochondrial reactive oxygen species (ROS). Here, we report that mitochondrial electron transport chain (ETC) complex I, II, III and V inhibitors all prevent NLRP3 inflammasome activation. Ectopic expression of Saccharomyces cerevisiae NADH dehydrogenase (NDI1) or Ciona intestinalis alternative oxidase, which can complement the functional loss of mitochondrial complex I or III, respectively, without generation of ROS, rescued NLRP3 inflammasome activation in the absence of endogenous mitochondrial complex I or complex III function. Metabolomics revealed phosphocreatine (PCr), which can sustain ATP levels, as a common metabolite that is diminished by mitochondrial ETC inhibitors. PCr depletion decreased ATP levels and NLRP3 inflammasome activation. Thus, the mitochondrial ETC sustains NLRP3 inflammasome activation through PCr-dependent generation of ATP, but via a ROS-independent mechanism.
Assuntos
Inflamassomos , Proteína 3 que Contém Domínio de Pirina da Família NLR , Trifosfato de Adenosina/metabolismo , Transporte de Elétrons , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Espécies Reativas de Oxigênio/metabolismoRESUMO
Reactive oxygen species (ROS) are key signalling molecules that enable cells to rapidly respond to different stimuli. In plants, ROS play a crucial role in abiotic and biotic stress sensing, integration of different environmental signals and activation of stress-response networks, thus contributing to the establishment of defence mechanisms and plant resilience. Recent advances in the study of ROS signalling in plants include the identification of ROS receptors and key regulatory hubs that connect ROS signalling with other important stress-response signal transduction pathways and hormones, as well as new roles for ROS in organelle-to-organelle and cell-to-cell signalling. Our understanding of how ROS are regulated in cells by balancing production, scavenging and transport has also increased. In this Review, we discuss these promising developments and how they might be used to increase plant resilience to environmental stress.