Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 222
Filtrar
1.
bioRxiv ; 2024 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-39282299

RESUMO

The yellow fever virus 17D (YFV-17D) live attenuated vaccine is considered one of the successful vaccines ever generated associated with high antiviral immunity, yet the signaling mechanisms that drive the response in infected cells are not understood. Here, we provide a molecular understanding of how metabolic stress and innate immune responses are linked to drive type I IFN expression in response to YFV-17D infection. Comparison of YFV-17D replication with its parental virus, YFV-Asibi, and a related dengue virus revealed that IFN expression requires RIG-I-like Receptor signaling through MAVS, as expected. However, YFV-17D uniquely induces mitochondrial respiration and major metabolic perturbations, including hyperactivation of electron transport to fuel ATP synthase. Mitochondrial hyperactivity generates reactive oxygen species (mROS) and peroxynitrite, blocking of which abrogated IFN expression in non-immune cells without reducing YFV-17D replication. Scavenging ROS in YFV-17D-infected human dendritic cells increased cell viability yet globally prevented expression of IFN signaling pathways. Thus, adaptation of YFV-17D for high growth uniquely imparts mitochondrial hyperactivity generating mROS and peroxynitrite as the critical messengers that convert a blunted IFN response into maximal activation of innate immunity essential for vaccine effectiveness.

2.
Proc Natl Acad Sci U S A ; 121(30): e2321972121, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-39008677

RESUMO

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection inhibits mitochondrial oxidative phosphorylation (OXPHOS) and elevates mitochondrial reactive oxygen species (ROS, mROS) which activates hypoxia-inducible factor-1alpha (HIF-1α), shifting metabolism toward glycolysis to drive viral biogenesis but also causing the release of mitochondrial DNA (mtDNA) and activation of innate immunity. To determine whether mitochondrially targeted antioxidants could mitigate these viral effects, we challenged mice expressing human angiotensin-converting enzyme 2 (ACE2) with SARS-CoV-2 and intervened using transgenic and pharmacological mitochondrially targeted catalytic antioxidants. Transgenic expression of mitochondrially targeted catalase (mCAT) or systemic treatment with EUK8 decreased weight loss, clinical severity, and circulating levels of mtDNA; as well as reduced lung levels of HIF-1α, viral proteins, and inflammatory cytokines. RNA-sequencing of infected lungs revealed that mCAT and Eukarion 8 (EUK8) up-regulated OXPHOS gene expression and down-regulated HIF-1α and its target genes as well as innate immune gene expression. These data demonstrate that SARS-CoV-2 pathology can be mitigated by catalytically reducing mROS, potentially providing a unique host-directed pharmacological therapy for COVID-19 which is not subject to viral mutational resistance.


Assuntos
Antioxidantes , COVID-19 , Camundongos Transgênicos , Mitocôndrias , Fosforilação Oxidativa , SARS-CoV-2 , Animais , Camundongos , COVID-19/virologia , COVID-19/metabolismo , COVID-19/imunologia , COVID-19/patologia , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Mitocôndrias/metabolismo , Mitocôndrias/efeitos dos fármacos , SARS-CoV-2/efeitos dos fármacos , Fosforilação Oxidativa/efeitos dos fármacos , Humanos , Enzima de Conversão de Angiotensina 2/metabolismo , Enzima de Conversão de Angiotensina 2/genética , Pulmão/virologia , Pulmão/patologia , Pulmão/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Catalase/metabolismo , Catalase/genética , Tratamento Farmacológico da COVID-19 , Modelos Animais de Doenças , Imunidade Inata
3.
bioRxiv ; 2024 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-38853873

RESUMO

Mitochondrial function is important for both energetic and anabolic metabolism. Pathogenic mitochondrial DNA (mtDNA) mutations directly impact these functions, resulting in the detrimental consequences seen in human mitochondrial diseases. The role of pathogenic mtDNA mutations in human cancers is less clear; while pathogenic mtDNA mutations are observed in some cancer types, they are almost absent in others. We report here that the proofreading mutant DNA polymerase gamma ( PolG D256A ) induced a high mtDNA mutation burden in non-small-cell lung cancer (NSCLC), and promoted the accumulation of defective mitochondria, which is responsible for decreased tumor cell proliferation and viability and increased cancer survival. In NSCLC cells, pathogenic mtDNA mutations increased glycolysis and caused dependence on glucose. The glucose dependency sustained mitochondrial energetics but at the cost of a decreased NAD+/NADH ratio that inhibited de novo serine synthesis. Insufficient serine synthesis, in turn, impaired the downstream synthesis of GSH and nucleotides, leading to impaired tumor growth that increased cancer survival. Unlike tumors with intact mitochondrial function, NSCLC with pathogenic mtDNA mutations were sensitive to dietary serine and glycine deprivation. Thus, mitochondrial function in NSCLC is required specifically to sustain sufficient serine synthesis for nucleotide production and redox homeostasis to support tumor growth, explaining why these cancers preserve functional mtDNA. In brief: High mtDNA mutation burden in non-small-cell lung cancer (NSCLC) leads to the accumulation of respiration-defective mitochondria and dependency on glucose and glycolytic metabolism. Defective respiratory metabolism causes a massive accumulation of cytosolic nicotinamide adenine dinucleotide + hydrogen (NADH), which impedes serine synthesis and, thereby, glutathione (GSH) and nucleotide synthesis, leading to impaired tumor growth and increased survival. Highlights: Proofreading mutations in Polymerase gamma led to a high burden of mitochondrial DNA mutations, promoting the accumulation of mitochondria with respiratory defects in NSCLC.Defective respiration led to reduced proliferation and viability of NSCLC cells increasing survival to cancer.Defective respiration caused glucose dependency to fuel elevated glycolysis.Altered glucose metabolism is associated with high NADH that limits serine synthesis, leading to impaired GSH and nucleotide production.Mitochondrial respiration defects sensitize NSCLC to dietary serine/glycine starvation, further increasing survival.

4.
Nat Commun ; 15(1): 4825, 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38862542

RESUMO

Our previous research revealed a key microRNA signature that is associated with spaceflight that can be used as a biomarker and to develop countermeasure treatments to mitigate the damage caused by space radiation. Here, we expand on this work to determine the biological factors rescued by the countermeasure treatment. We performed RNA-sequencing and transcriptomic analysis on 3D microvessel cell cultures exposed to simulated deep space radiation (0.5 Gy of Galactic Cosmic Radiation) with and without the antagonists to three microRNAs: miR-16-5p, miR-125b-5p, and let-7a-5p (i.e., antagomirs). Significant reduction of inflammation and DNA double strand breaks (DSBs) activity and rescue of mitochondria functions are observed after antagomir treatment. Using data from astronaut participants in the NASA Twin Study, Inspiration4, and JAXA missions, we reveal the genes and pathways implicated in the action of these antagomirs are altered in humans. Our findings indicate a countermeasure strategy that can potentially be utilized by astronauts in spaceflight missions to mitigate space radiation damage.


Assuntos
Astronautas , Radiação Cósmica , MicroRNAs , Voo Espacial , MicroRNAs/genética , MicroRNAs/metabolismo , Humanos , Radiação Cósmica/efeitos adversos , Quebras de DNA de Cadeia Dupla/efeitos da radiação , Lesões por Radiação/genética , Lesões por Radiação/prevenção & controle , Masculino , Mitocôndrias/efeitos da radiação , Mitocôndrias/metabolismo , Mitocôndrias/genética , Feminino , Adulto
5.
Nat Commun ; 15(1): 4778, 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38862479

RESUMO

Impairment of the central nervous system (CNS) poses a significant health risk for astronauts during long-duration space missions. In this study, we employed an innovative approach by integrating single-cell multiomics (transcriptomics and chromatin accessibility) with spatial transcriptomics to elucidate the impact of spaceflight on the mouse brain in female mice. Our comparative analysis between ground control and spaceflight-exposed animals revealed significant alterations in essential brain processes including neurogenesis, synaptogenesis and synaptic transmission, particularly affecting the cortex, hippocampus, striatum and neuroendocrine structures. Additionally, we observed astrocyte activation and signs of immune dysfunction. At the pathway level, some spaceflight-induced changes in the brain exhibit similarities with neurodegenerative disorders, marked by oxidative stress and protein misfolding. Our integrated spatial multiomics approach serves as a stepping stone towards understanding spaceflight-induced CNS impairments at the level of individual brain regions and cell types, and provides a basis for comparison in future spaceflight studies. For broader scientific impact, all datasets from this study are available through an interactive data portal, as well as the National Aeronautics and Space Administration (NASA) Open Science Data Repository (OSDR).


Assuntos
Encéfalo , Neurônios , Voo Espacial , Animais , Camundongos , Feminino , Encéfalo/metabolismo , Encéfalo/patologia , Neurônios/metabolismo , Transcriptoma , Neurogênese , Análise de Célula Única , Camundongos Endogâmicos C57BL , Transmissão Sináptica , Ausência de Peso/efeitos adversos , Astrócitos/metabolismo , Estresse Oxidativo , Perfilação da Expressão Gênica , Multiômica
6.
bioRxiv ; 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38712254

RESUMO

Splicing factor mutations are common in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), but how they alter cellular functions is unclear. We show that the pathogenic SRSF2P95H/+ mutation disrupts the splicing of mitochondrial mRNAs, impairs mitochondrial complex I function, and robustly increases mitophagy. We also identified a mitochondrial surveillance mechanism by which mitochondrial dysfunction modifies splicing of the mitophagy activator PINK1 to remove a poison intron, increasing the stability and abundance of PINK1 mRNA and protein. SRSF2P95H-induced mitochondrial dysfunction increased PINK1 expression through this mechanism, which is essential for survival of SRSF2P95H/+ cells. Inhibition of splicing with a glycogen synthase kinase 3 inhibitor promoted retention of the poison intron, impairing mitophagy and activating apoptosis in SRSF2P95H/+ cells. These data reveal a homeostatic mechanism for sensing mitochondrial stress through PINK1 splicing and identify increased mitophagy as a disease marker and a therapeutic vulnerability in SRSF2P95H mutant MDS and AML.

7.
J Clin Invest ; 134(12)2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38713535

RESUMO

Splicing factor mutations are common in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), but how they alter cellular functions is unclear. We show that the pathogenic SRSF2P95H/+ mutation disrupts the splicing of mitochondrial mRNAs, impairs mitochondrial complex I function, and robustly increases mitophagy. We also identified a mitochondrial surveillance mechanism by which mitochondrial dysfunction modifies splicing of the mitophagy activator PINK1 to remove a poison intron, increasing the stability and abundance of PINK1 mRNA and protein. SRSF2P95H-induced mitochondrial dysfunction increased PINK1 expression through this mechanism, which is essential for survival of SRSF2P95H/+ cells. Inhibition of splicing with a glycogen synthase kinase 3 inhibitor promoted retention of the poison intron, impairing mitophagy and activating apoptosis in SRSF2P95H/+ cells. These data reveal a homeostatic mechanism for sensing mitochondrial stress through PINK1 splicing and identify increased mitophagy as a disease marker and a therapeutic vulnerability in SRSF2P95H mutant MDS and AML.


Assuntos
Leucemia Mieloide Aguda , Mitocôndrias , Mitofagia , Proteínas Quinases , Fatores de Processamento de Serina-Arginina , Animais , Humanos , Camundongos , Substituição de Aminoácidos , Linhagem Celular Tumoral , Neoplasias Hematológicas/genética , Neoplasias Hematológicas/patologia , Neoplasias Hematológicas/metabolismo , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Leucemia Mieloide Aguda/metabolismo , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Mitofagia/genética , Mutação de Sentido Incorreto , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/patologia , Síndromes Mielodisplásicas/metabolismo , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Splicing de RNA , Fatores de Processamento de Serina-Arginina/genética , Fatores de Processamento de Serina-Arginina/metabolismo
8.
Pharmacol Res ; 204: 107170, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38614374

RESUMO

To determine the effects of SARS-CoV-2 infection on cellular metabolism, we conducted an exhaustive survey of the cellular metabolic pathways modulated by SARS-CoV-2 infection and confirmed their importance for SARS-CoV-2 propagation by cataloging the effects of specific pathway inhibitors. This revealed that SARS-CoV-2 strongly inhibits mitochondrial oxidative phosphorylation (OXPHOS) resulting in increased mitochondrial reactive oxygen species (mROS) production. The elevated mROS stabilizes HIF-1α which redirects carbon molecules from mitochondrial oxidation through glycolysis and the pentose phosphate pathway (PPP) to provide substrates for viral biogenesis. mROS also induces the release of mitochondrial DNA (mtDNA) which activates innate immunity. The restructuring of cellular energy metabolism is mediated in part by SARS-CoV-2 Orf8 and Orf10 whose expression restructures nuclear DNA (nDNA) and mtDNA OXPHOS gene expression. These viral proteins likely alter the epigenome, either by directly altering histone modifications or by modulating mitochondrial metabolite substrates of epigenome modification enzymes, potentially silencing OXPHOS gene expression and contributing to long-COVID.


Assuntos
COVID-19 , Mitocôndrias , Fosforilação Oxidativa , SARS-CoV-2 , Humanos , COVID-19/metabolismo , COVID-19/genética , COVID-19/virologia , Mitocôndrias/metabolismo , Mitocôndrias/genética , Espécies Reativas de Oxigênio/metabolismo , Epigênese Genética , Metabolismo Energético , Epigenômica , Animais
9.
Commun Biol ; 7(1): 428, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38594590

RESUMO

NADH autofluorescence imaging is a promising approach for visualizing energy metabolism at the single-cell level. However, it is sensitive to the redox ratio and the total NAD(H) amount, which can change independently from each other, for example with aging. Here, we evaluate the potential of fluorescence lifetime imaging microscopy (FLIM) of NADH to differentiate between these modalities.We perform targeted modifications of the NAD(H) pool size and ratio in cells and mice and assess the impact on NADH FLIM. We show that NADH FLIM is sensitive to NAD(H) pool size, mimicking the effect of redox alterations. However, individual components of the fluorescence lifetime are differently impacted by redox versus pool size changes, allowing us to distinguish both modalities using only FLIM. Our results emphasize NADH FLIM's potential for evaluating cellular metabolism and relative NAD(H) levels with high spatial resolution, providing a crucial tool for our understanding of aging and metabolism.


Assuntos
Metabolismo Energético , NAD , Camundongos , Animais , NAD/metabolismo , Microscopia de Fluorescência , Oxirredução , Envelhecimento
10.
Sci Immunol ; 9(93): eadj7238, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38489349

RESUMO

Adaptive immunity requires the expansion of high-affinity lymphocytes from a heterogeneous pool. Whereas current models explain this through signal transduction, we hypothesized that antigen affinity tunes discrete metabolic pathways to license clonal lymphocyte dynamics. Here, we identify nicotinamide adenine dinucleotide (NAD) biosynthesis as a biochemical hub for the T cell receptor affinity-dependent metabolome. Through this central anabolic role, we found that NAD biosynthesis governs a quiescence exit checkpoint, thereby pacing proliferation. Normalizing cellular NAD(H) likewise normalizes proliferation across affinities, and enhancing NAD biosynthesis permits the expansion of lower affinity clones. Furthermore, single-cell differences in NAD(H) could predict division potential for both T and B cells, before the first division, unmixing proliferative heterogeneity. We believe that this supports a broader paradigm in which complex signaling networks converge on metabolic pathways to control single-cell behavior.


Assuntos
Linfócitos , NAD , Linfócitos/metabolismo , Metaboloma , Transdução de Sinais
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA