RESUMEN
In metazoans mitochondrial DNA (mtDNA) or retrotransposon cDNA released to cytoplasm are degraded by nucleases to prevent sterile inflammation. It remains unknown whether degradation of these DNA also prevents nuclear genome instability. We used an amplicon sequencing-based method in yeast enabling analysis of millions of DSB repair products. In non-dividing stationary phase cells, Pol4-mediated non-homologous end-joining increases, resulting in frequent insertions of 1-3 nucleotides, and insertions of mtDNA (NUMTs) or retrotransposon cDNA. Yeast EndoG (Nuc1) nuclease limits insertion of cDNA and transfer of very long mtDNA ( >10 kb) to the nucleus, where it forms unstable circles, while promoting the formation of short NUMTs (~45-200 bp). Nuc1 also regulates transfer of extranuclear DNA to nucleus in aging or meiosis. We propose that Nuc1 preserves genome stability by degrading retrotransposon cDNA and long mtDNA, while short NUMTs originate from incompletely degraded mtDNA. This work suggests that nucleases eliminating extranuclear DNA preserve genome stability.
Asunto(s)
ADN Mitocondrial , Inestabilidad Genómica , Retroelementos , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Retroelementos/genética , Núcleo Celular/metabolismo , Núcleo Celular/genética , Reparación del ADN por Unión de Extremidades , Roturas del ADN de Doble Cadena , Meiosis/genética , Endodesoxirribonucleasas/metabolismo , Endodesoxirribonucleasas/genéticaRESUMEN
Metabolic syndrome is a growing concern in developed societies and due to its polygenic nature, the genetic component is only slowly being elucidated. Common mitochondrial DNA sequence variants have been associated with symptoms of metabolic syndrome and may, therefore, be relevant players in the genetics of metabolic syndrome. We investigate the effect of mitochondrial sequence variation on the metabolic phenotype in conplastic rat strains with identical nuclear but unique mitochondrial genomes, challenged by high-fat diet. We find that the variation in mitochondrial rRNA sequence represents risk factor in the insulin resistance development, which is associated with diacylglycerols accumulation, induced by tissue-specific reduction of the oxidative capacity. These metabolic perturbations stem from the 12S rRNA sequence variation affecting mitochondrial ribosome assembly and translation. Our work demonstrates that physiological variation in mitochondrial rRNA might represent a relevant underlying factor in the progression of metabolic syndrome.
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Haplotipos , Síndrome Metabólico , ARN Ribosómico , Síndrome Metabólico/genética , Síndrome Metabólico/metabolismo , Animales , ARN Ribosómico/genética , ARN Ribosómico/metabolismo , Ratas , Masculino , ARN Mitocondrial/genética , ARN Mitocondrial/metabolismo , Predisposición Genética a la Enfermedad , Resistencia a la Insulina/genética , Dieta Alta en Grasa/efectos adversos , Mitocondrias/metabolismo , Mitocondrias/genética , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismoRESUMEN
High mitochondrial DNA (mtDNA) amount has been reported to be beneficial for resistance and recovery of metabolic stress, while increased mtDNA synthesis activity can drive aging signs. The intriguing contrast of these two mtDNA boosting outcomes prompted us to jointly elevate mtDNA amount and frequency of replication in mice. We report that high activity of mtDNA synthesis inhibits perinatal metabolic maturation of the heart. The offspring of the asymptomatic parental lines are born healthy but manifest dilated cardiomyopathy and cardiac collapse during the first days of life. The pathogenesis, further enhanced by mtDNA mutagenesis, involves prenatal upregulation of mitochondrial integrated stress response and the ferroptosis-inducer MESH1, leading to cardiac fibrosis and cardiomyocyte death after birth. Our evidence indicates that the tight control of mtDNA replication is critical for early cardiac homeostasis. Importantly, ferroptosis sensitivity is a potential targetable mechanism for infantile-onset cardiomyopathy, a common manifestation of mitochondrial diseases.
Asunto(s)
Replicación del ADN , ADN Mitocondrial , Miocitos Cardíacos , Animales , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Ratones , Miocitos Cardíacos/metabolismo , Femenino , Masculino , Cardiomiopatía Dilatada/genética , Cardiomiopatía Dilatada/metabolismo , Cardiomiopatía Dilatada/patología , Ferroptosis/genética , Miocardio/metabolismo , Miocardio/patología , Mitocondrias Cardíacas/metabolismo , Mitocondrias Cardíacas/genética , Ratones Endogámicos C57BL , Animales Recién Nacidos , Humanos , Corazón/fisiopatología , FibrosisRESUMEN
Cellular oxidative stress mediated by intrinsic and/or extrinsic reactive oxygen species (ROS) is associated with disease pathogenesis. Oxidative DNA damage can naturally be substituted by mitochondrial DNA (mtDNA), leading to base lesion/strand break formation, copy number changes, and mutations. In this study, we devised a single test for the sensitive quantification of acute mtDNA damage, repair, and copy number changes using supercoiling-sensitive quantitative PCR (ss-qPCR) and examined how oxidative stress-related mtDNA damage responses occur in oral cancer cells. We observed that exogenous hydrogen peroxide (H2O2) induced dynamic mtDNA damage responses, as reflected by early structural DNA damage, followed by DNA repair if damage did not exceed a particular threshold. However, high oxidative stress levels induced persistent mtDNA damage and caused a 5-30-fold depletion in mtDNA copy numbers over late responses. This dramatic depletion was associated with significant growth arrest and apoptosis, suggesting persistent functional consequences. Moreover, oral cancer cells responded differentially to oxidative injury when compared with normal cells, and different ROS species triggered different biological consequences under stress conditions. In conclusion, we developed a new method for the sensitive detection of mtDNA damage and copy number changes, with exogenous H2O2 inducing dynamic mtDNA damage responses associated with functional changes in stressed cancer cells. Finally, our method can help characterize oxidative DNA damage in cancer and other human diseases.
Asunto(s)
Daño del ADN , ADN Mitocondrial , Peróxido de Hidrógeno , Neoplasias de la Boca , Estrés Oxidativo , Especies Reactivas de Oxígeno , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Estrés Oxidativo/efectos de los fármacos , Humanos , Neoplasias de la Boca/genética , Neoplasias de la Boca/patología , Neoplasias de la Boca/metabolismo , Peróxido de Hidrógeno/farmacología , Línea Celular Tumoral , Especies Reactivas de Oxígeno/metabolismo , Reparación del ADN , Apoptosis/efectos de los fármacos , Variaciones en el Número de Copia de ADNRESUMEN
Immune checkpoint blockade (ICB) has emerged as a promising therapeutic option for hepatocellular carcinoma (HCC), but resistance to ICB occurs and patient responses vary. Here, we uncover protein arginine methyltransferase 3 (PRMT3) as a driver for immunotherapy resistance in HCC. We show that PRMT3 expression is induced by ICB-activated T cells via an interferon-gamma (IFNγ)-STAT1 signaling pathway, and higher PRMT3 expression levels correlate with reduced numbers of tumor-infiltrating CD8+ T cells and poorer response to ICB. Genetic depletion or pharmacological inhibition of PRMT3 elicits an influx of T cells into tumors and reduces tumor size in HCC mouse models. Mechanistically, PRMT3 methylates HSP60 at R446 to induce HSP60 oligomerization and maintain mitochondrial homeostasis. Targeting PRMT3-dependent HSP60 methylation disrupts mitochondrial integrity and increases mitochondrial DNA (mtDNA) leakage, which results in cGAS/STING-mediated anti-tumor immunity. Lastly, blocking PRMT3 functions synergize with PD-1 blockade in HCC mouse models. Our study thus identifies PRMT3 as a potential biomarker and therapeutic target to overcome immunotherapy resistance in HCC.
Asunto(s)
Carcinoma Hepatocelular , Chaperonina 60 , Neoplasias Hepáticas , Proteínas de la Membrana , Nucleotidiltransferasas , Proteína-Arginina N-Metiltransferasas , Transducción de Señal , Animales , Proteína-Arginina N-Metiltransferasas/metabolismo , Proteína-Arginina N-Metiltransferasas/genética , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Humanos , Ratones , Carcinoma Hepatocelular/inmunología , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patología , Neoplasias Hepáticas/inmunología , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Chaperonina 60/metabolismo , Chaperonina 60/genética , Línea Celular Tumoral , Metilación , Inhibidores de Puntos de Control Inmunológico/farmacología , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Mitocondrias/metabolismo , Ratones Endogámicos C57BL , ADN Mitocondrial/genética , ADN Mitocondrial/inmunología , ADN Mitocondrial/metabolismo , Interferón gamma/metabolismo , Interferón gamma/inmunología , MasculinoRESUMEN
Mitochondria play pivotal roles in sustaining various biological functions including energy metabolism, cellular signaling transduction, and innate immune responses. Viruses exploit cellular metabolic synthesis to facilitate viral replication, potentially disrupting mitochondrial functions and subsequently eliciting a cascade of proinflammatory responses in host cells. Additionally, the disruption of mitochondrial membranes is involved in immune regulation. During viral infections, mitochondria orchestrate innate immune responses through the generation of reactive oxygen species (ROS) and the release of mitochondrial DNA, which serves as an effective defense mechanism against virus invasion. The targeting of mitochondrial damage may represent a novel approach to antiviral intervention. This review summarizes the regulatory mechanism underlying proinflammatory response induced by mitochondrial damage during viral infections, providing new insights for antiviral strategies.
Asunto(s)
Inmunidad Innata , Mitocondrias , Especies Reactivas de Oxígeno , Virosis , Humanos , Mitocondrias/metabolismo , Virosis/inmunología , Virosis/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Animales , Inflamación/metabolismo , Inflamación/inmunología , ADN Mitocondrial/metabolismo , Transducción de SeñalRESUMEN
One of the therapeutic approaches to age-related diseases is modulation of body cell metabolism through certain diets or their pharmacological mimetics. The ketogenic diet significantly affects cell energy metabolism and functioning of mitochondria, which has been actively studied in various age-related pathologies. Here, we investigated the effect of the ketogenic diet mimetic beta-hydroxybutyrate (BHB) on the expression of genes regulating mitochondrial biogenesis (Ppargc1a, Nrf1, Tfam), quality control (Sqstm1), functioning of the antioxidant system (Nfe2l2, Gpx1, Gpx3, Srxn1, Txnrd2, Slc6a9, Slc7a11), and inflammatory response (Il1b, Tnf, Ptgs2, Gfap) in the brain, lungs, heart, liver, kidneys, and muscles of young and old rats. We also analyzed mitochondrial DNA (mtDNA) copy number, accumulation of mtDNA damage, and levels of oxidative stress based on the concentration of reduced glutathione and thiobarbituric acid-reactive substances (TBARS). In some organs, aging disrupted mitochondrial biogenesis and functioning of cell antioxidant system, which was accompanied by the increased oxidative stress and inflammation. Administration of BHB for 2 weeks had different effects on the organs of young and old rats. In particular, BHB upregulated expression of genes coding for proteins associated with the mitochondrial biogenesis and antioxidant system, especially in the liver and muscles of young (but not old) rats. At the same time, BHB contributed to the reduction of TBARS in the kidneys of old rats. Therefore, our study has shown that administration of ketone bodies significantly affected gene expression in organs, especially in young rats, by promoting mitochondrial biogenesis, improving the functioning of the antioxidant defense system, and partially reducing the level of oxidative stress. However, these changes were much less pronounced in old animals.
Asunto(s)
Ácido 3-Hidroxibutírico , Envejecimiento , Inflamación , Biogénesis de Organelos , Estrés Oxidativo , Ratas Wistar , Animales , Estrés Oxidativo/efectos de los fármacos , Ratas , Ácido 3-Hidroxibutírico/farmacología , Masculino , Inflamación/metabolismo , Envejecimiento/metabolismo , Biomarcadores/metabolismo , ADN Mitocondrial/metabolismo , Mitocondrias/metabolismo , Mitocondrias/efectos de los fármacosRESUMEN
Protein import and genome replication are essential processes for mitochondrial biogenesis and propagation. The J-domain proteins Pam16 and Pam18 regulate the presequence translocase of the mitochondrial inner membrane. In the protozoan Trypanosoma brucei, their counterparts are TbPam16 and TbPam18, which are essential for the procyclic form (PCF) of the parasite, though not involved in mitochondrial protein import. Here, we show that during evolution, the 2 proteins have been repurposed to regulate the replication of maxicircles within the intricate kDNA network, the most complex mitochondrial genome known. TbPam18 and TbPam16 have inactive J-domains suggesting a function independent of heat shock proteins. However, their single transmembrane domain is essential for function. Pulldown of TbPam16 identifies a putative client protein, termed MaRF11, the depletion of which causes the selective loss of maxicircles, akin to the effects observed for TbPam18 and TbPam16. Moreover, depletion of the mitochondrial proteasome results in increased levels of MaRF11. Thus, we have discovered a protein complex comprising TbPam18, TbPam16, and MaRF11, that controls maxicircle replication. We propose a working model in which the matrix protein MaRF11 functions downstream of the 2 integral inner membrane proteins TbPam18 and TbPam16. Moreover, we suggest that the levels of MaRF11 are controlled by the mitochondrial proteasome.
Asunto(s)
Replicación del ADN , ADN Mitocondrial , Proteínas Protozoarias , Trypanosoma brucei brucei , Trypanosoma brucei brucei/metabolismo , Trypanosoma brucei brucei/genética , Proteínas Protozoarias/metabolismo , Proteínas Protozoarias/genética , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Proteínas Mitocondriales/metabolismo , Proteínas Mitocondriales/genética , Mitocondrias/metabolismo , Mitocondrias/genética , Evolución MolecularRESUMEN
The double-stranded DNA (dsDNA) sensor STING has been increasingly implicated in responses to "sterile" endogenous threats and pathogens without nominal DNA or cyclic di-nucleotide stimuli. Previous work showed an endoplasmic reticulum (ER) stress response, known as the unfolded protein response (UPR), activates STING. Herein, we sought to determine if ER stress generated a STING ligand, and to identify the UPR pathways involved. Induction of IFN-ß expression following stimulation with the UPR inducer thapsigargin (TPG) or oxygen glucose deprivation required both STING and the dsDNA-sensing cyclic GMP-AMP synthase (cGAS). Furthermore, TPG increased cytosolic mitochondrial DNA, and immunofluorescence visualized dsDNA punctae in murine and human cells, providing a cGAS stimulus. N-acetylcysteine decreased IFN-ß induction by TPG, implicating reactive oxygen species (ROS). However, mitoTEMPO, a mitochondrial oxidative stress inhibitor did not impact TPG-induced IFN. On the other hand, inhibiting the inositol requiring enzyme 1 (IRE1) ER stress sensor and its target transcription factor XBP1 decreased the generation of cytosolic dsDNA. iNOS upregulation was XBP1-dependent, and an iNOS inhibitor decreased cytosolic dsDNA and IFN-ß, implicating ROS downstream of the IRE1-XBP1 pathway. Inhibition of the PKR-like ER kinase (PERK) pathway also attenuated cytoplasmic dsDNA release. The PERK-regulated apoptotic factor Bim was required for both dsDNA release and IFN-ß mRNA induction. Finally, XBP1 and PERK pathways contributed to cytosolic dsDNA release and IFN-induction by the RNA virus, Vesicular Stomatitis Virus (VSV). Together, our findings suggest that ER stressors, including viral pathogens without nominal STING or cGAS ligands such as RNA viruses, trigger multiple canonical UPR pathways that cooperate to activate STING and downstream IFN-ß via mitochondrial dsDNA release.
Asunto(s)
Citosol , Estrés del Retículo Endoplásmico , Interferón beta , Proteínas de la Membrana , Nucleotidiltransferasas , Respuesta de Proteína Desplegada , Humanos , Animales , Ratones , Nucleotidiltransferasas/metabolismo , Citosol/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Interferón beta/metabolismo , ADN/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Transducción de Señal , eIF-2 Quinasa/metabolismo , Endorribonucleasas/metabolismo , Proteína 1 de Unión a la X-Box/metabolismo , Proteína 1 de Unión a la X-Box/genética , Tapsigargina/farmacología , Especies Reactivas de Oxígeno/metabolismo , Activación Transcripcional , ADN Mitocondrial/metabolismoRESUMEN
Astrocytes display context-specific diversity in their functions and respond to noxious stimuli between brain regions. Astrocytic mitochondria have emerged as key players in governing astrocytic functional heterogeneity, given their ability to dynamically adapt their morphology to regional demands on ATP generation and Ca2+ buffering functions. Although there is reciprocal regulation between mitochondrial dynamics and mitochondrial Ca2+ signaling in astrocytes, the extent of this regulation in astrocytes from different brain regions remains unexplored. Brain-wide, experimentally induced mitochondrial DNA (mtDNA) loss in astrocytes showed that mtDNA integrity is critical for astrocyte function, however, possible diverse responses to this noxious stimulus between brain areas were not reported in these experiments. To selectively damage mtDNA in astrocytes in a brain-region-specific manner, we developed a novel adeno-associated virus (AAV)-based tool, Mito-PstI expressing the restriction enzyme PstI, specifically in astrocytic mitochondria. Here, we applied Mito-PstI to two brain regions, the dorsolateral striatum and dentate gyrus, and we show that Mito-PstI induces astrocytic mtDNA loss in vivo, but with remarkable brain-region-dependent differences on mitochondrial dynamics, Ca2+ fluxes, and astrocytic and microglial reactivity. Thus, AAV-Mito-PstI is a novel tool to explore the relationship between astrocytic mitochondrial network dynamics and astrocytic mitochondrial Ca2+ signaling in a brain-region-selective manner.
Asunto(s)
Astrocitos , Daño del ADN , ADN Mitocondrial , Mitocondrias , Astrocitos/metabolismo , Animales , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Ratones , Mitocondrias/metabolismo , Dependovirus/genética , Calcio/metabolismo , Encéfalo/metabolismo , Masculino , Señalización del Calcio , Ratones Endogámicos C57BL , Dinámicas Mitocondriales , Giro Dentado/metabolismoRESUMEN
There is a large body of evidence that cellular metabolism governs inflammation, and that inflammation contributes to the progression of atherosclerosis. However, whether mitochondrial DNA synthesis affects macrophage function and atherosclerosis pathology is not fully understood. Here we show, by transcriptomic analyzes of plaque macrophages, spatial single cell transcriptomics of atherosclerotic plaques, and functional experiments, that mitochondrial DNA (mtDNA) synthesis in atherosclerotic plaque macrophages are triggered by vascular cell adhesion molecule 1 (VCAM-1) under inflammatory conditions in both humans and mice. Mechanistically, VCAM-1 activates C/EBPα, which binds to the promoters of key mitochondrial biogenesis genes - Cmpk2 and Pgc1a. Increased CMPK2 and PGC-1α expression triggers mtDNA synthesis, which activates STING-mediated inflammation. Consistently, atherosclerosis and inflammation are less severe in Apoe-/- mice lacking Vcam1 in macrophages. Downregulation of macrophage-specific VCAM-1 in vivo leads to decreased expression of LYZ1 and FCOR, involved in STING signalling. Finally, VCAM-1 expression in human carotid plaque macrophages correlates with necrotic core area, mitochondrial volume, and oxidative damage to DNA. Collectively, our study highlights the importance of macrophage VCAM-1 in inflammation and atherogenesis pathology and proposes a self-acerbating pathway involving increased mtDNA synthesis.
Asunto(s)
Aterosclerosis , ADN Mitocondrial , Inflamación , Macrófagos , Proteínas de la Membrana , Placa Aterosclerótica , Molécula 1 de Adhesión Celular Vascular , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Animales , Molécula 1 de Adhesión Celular Vascular/metabolismo , Molécula 1 de Adhesión Celular Vascular/genética , Aterosclerosis/metabolismo , Aterosclerosis/patología , Aterosclerosis/genética , Macrófagos/metabolismo , Humanos , Inflamación/metabolismo , Inflamación/patología , Inflamación/genética , Ratones , Placa Aterosclerótica/patología , Placa Aterosclerótica/metabolismo , Placa Aterosclerótica/genética , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Masculino , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/genética , Ratones Endogámicos C57BL , Mitocondrias/metabolismo , Mitocondrias/patología , Ratones Noqueados para ApoE , Transducción de Señal , Femenino , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismoRESUMEN
This study aimed to comprehensively assess the metabolic, mitochondrial, and inflammatory effects of first-line efavirenz, emtricitabine, and tenofovir disoproxil fumarate (EFV/FTC/TDF) single-tablet regimen (STR) relative to untreated asymptomatic HIV infection. To this end, we analyzed 29 people with HIV (PWH) treated for at least one year with this regimen vs. 33 antiretroviral-naïve PWH. Excellent therapeutic activity was accompanied by significant alterations in metabolic parameters. The treatment group showed increased plasmatic levels of glucose, total cholesterol and its fractions (LDL and HDL), triglycerides, and hepatic enzymes (GGT, ALP); conversely, bilirubin levels (total and indirect fraction) decreased in the treated cohort. Mitochondrial performance was preserved overall and treatment administration even promoted the recovery of mitochondrial DNA (mtDNA) content depleted by the virus, although this was not accompanied by the recovery in some of their encoded proteins (since cytochrome c oxidase II was significantly decreased). Inflammatory profile (TNFα, IL-6), ameliorated after treatment in accordance with viral reduction and the recovery of TNFα levels correlated to mtDNA cell restoration. Thus, although this regimen causes subclinical metabolic alterations, its antiviral and anti-inflammatory properties may be associated with partial improvement in mitochondrial function.
Asunto(s)
Alquinos , Fármacos Anti-VIH , Benzoxazinas , Ciclopropanos , ADN Mitocondrial , Emtricitabina , Infecciones por VIH , Mitocondrias , Tenofovir , Humanos , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/metabolismo , Masculino , Femenino , Adulto , Mitocondrias/metabolismo , Mitocondrias/efectos de los fármacos , Benzoxazinas/uso terapéutico , Benzoxazinas/farmacología , Fármacos Anti-VIH/uso terapéutico , Fármacos Anti-VIH/efectos adversos , Ciclopropanos/uso terapéutico , Tenofovir/uso terapéutico , Persona de Mediana Edad , Emtricitabina/uso terapéutico , ADN Mitocondrial/metabolismo , InflamaciónRESUMEN
Mitochondrial DNA (mtDNA) is pivotal for mitochondrial morphology and function. Upon mtDNA damage, mitochondria undergo quality control mechanisms, including fusion, fission, and mitophagy. Real-time monitoring of mtDNA enables a deeper understanding of its effect on mitochondrial function and morphology. Controllable induction and real-time tracking of mtDNA dynamics and behavior are of paramount significance for studying mitochondrial function and morphology, facilitating a deeper understanding of mitochondria-related diseases. In this work, a fluorescent platinum complex was designed and developed that not only induces mitochondrial DNA (mtDNA) aggregation but also triggers mitochondrial autophagy (mitophagy) through the MDV pathway for damaged mtDNA clearance in living cells. Additionally, this complex allows for the real-time monitoring of these processes. This complex may serve as a valuable tool for studying mitochondrial microautophagy and holds promise for broader applications in cellular imaging and disease research.
Asunto(s)
ADN Mitocondrial , Colorantes Fluorescentes , Mitofagia , ADN Mitocondrial/metabolismo , Humanos , Colorantes Fluorescentes/química , Mitocondrias/metabolismo , Platino (Metal)/química , Células HeLaRESUMEN
Across eukaryotes, most genes required for mitochondrial function have been transferred to, or otherwise acquired by, the nucleus. Encoding genes in the nucleus has many advantages. So why do mitochondria retain any genes at all? Why does the set of mtDNA genes vary so much across different species? And how do species maintain functionality in the mtDNA genes they do retain? In this review, we will discuss some possible answers to these questions, attempting a broad perspective across eukaryotes. We hope to cover some interesting features which may be less familiar from the perspective of particular species, including the ubiquity of recombination outside bilaterian animals, encrypted chainmail-like mtDNA, single genes split over multiple mtDNA chromosomes, triparental inheritance, gene transfer by grafting, gain of mtDNA recombination factors, social networks of mitochondria, and the role of mtDNA dysfunction in feeding the world. We will discuss a unifying picture where organismal ecology and gene-specific features together influence whether organism X retains mtDNA gene Y, and where ecology and development together determine which strategies, importantly including recombination, are used to maintain the mtDNA genes that are retained.
Asunto(s)
ADN Mitocondrial , Evolución Molecular , Animales , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Eucariontes/genética , Humanos , Recombinación Genética , Mitocondrias/genética , Mitocondrias/metabolismo , Genes MitocondrialesRESUMEN
Gut microbe dysbiosis increases repetitive inflammatory responses, leading to an increase in the incidence of colorectal cancer. Recent studies have revealed that specific microbial species directly instigate mutations in the host nucleus DNA, thereby accelerating the progression of colorectal cancer. Given the well-established role of mitochondrial dysfunction in promoting colorectal cancer, it is reasonable to postulate that gut microbes may induce mitochondrial gene mutations, thereby inducing mitochondrial dysfunction. In this review, we focus on gut microbial genotoxins and their known and potential targets in mitochondrial genes. Consequently, we propose that targeted disruption of genotoxin transport pathways may effectively reduce the rate of mitochondrial gene mutations and yield substantial benefits for the prevention of colorectal carcinogenesis.
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Carcinogénesis , Neoplasias Colorrectales , Microbioma Gastrointestinal , Mitocondrias , Mutágenos , Mutación , Humanos , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/microbiología , Mitocondrias/metabolismo , Mitocondrias/genética , Microbioma Gastrointestinal/genética , Mutágenos/toxicidad , Carcinogénesis/genética , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Disbiosis/genética , AnimalesRESUMEN
In an aging society, unveiling new anti-aging strategies to prevent and combat aging-related diseases is of utmost importance. Mitochondria are the primary ATP production sites and key regulators of programmed cell death. Consequently, these highly dynamic organelles play a central role in maintaining tissue function, and mitochondrial dysfunction is a pivotal factor in the progressive age-related decline in cellular homeostasis and organ function. The current review examines recent advances in understanding the interplay between mitochondrial dysfunction and organ-specific aging. Thereby, we dissect molecular mechanisms underlying mitochondrial impairment associated with the deterioration of organ function, exploring the role of mitochondrial DNA, reactive oxygen species homeostasis, metabolic activity, damage-associated molecular patterns, biogenesis, turnover, and dynamics. We also highlight emerging therapeutic strategies in preclinical and clinical tests that are supposed to rejuvenate mitochondrial function, such as antioxidants, mitochondrial biogenesis stimulators, and modulators of mitochondrial turnover and dynamics. Furthermore, we discuss potential benefits and challenges associated with the use of these interventions, emphasizing the need for organ-specific approaches given the unique mitochondrial characteristics of different tissues. In conclusion, this review highlights the therapeutic potential of addressing mitochondrial dysfunction to mitigate organ-specific aging, focusing on the skin, liver, lung, brain, skeletal muscle, and lung, as well as on the reproductive, immune, and cardiovascular systems. Based on a comprehensive understanding of the multifaceted roles of mitochondria, innovative therapeutic strategies may be developed and optimized to combat biological aging and promote healthy aging across diverse organ systems.
Asunto(s)
Envejecimiento , Mitocondrias , Humanos , Envejecimiento/metabolismo , Envejecimiento/fisiología , Animales , Mitocondrias/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Especificidad de Órganos , ADN Mitocondrial/metabolismo , Antioxidantes/farmacologíaRESUMEN
Disrupting mitochondrial function in malignant cells is a promising strategy to enhance anticancer immunity. We have recently demonstrated that depriving colorectal cancer cells of serine results in mitochondrial dysfunction coupled with the cytosolic accumulation of mitochondrial DNA and consequent activation of CGAS- and STING-dependent tumor-targeting immune responses.
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ADN Mitocondrial , Mitocondrias , Animales , Humanos , Neoplasias Colorrectales/inmunología , Neoplasias Colorrectales/patología , ADN Mitocondrial/metabolismo , ADN Mitocondrial/genética , Proteínas de la Membrana/genética , Proteínas de la Membrana/inmunología , Proteínas de la Membrana/metabolismo , Mitocondrias/metabolismo , Nucleotidiltransferasas/genética , Nucleotidiltransferasas/inmunología , Nucleotidiltransferasas/metabolismoRESUMEN
DNA damage has been implicated in the stimulation of the type 1 interferon (T1IFN) response. Here, we show that downregulation of the DNA repair protein, polynucleotide kinase/phosphatase (PNKP), in a variety of cell lines causes robust phosphorylation of STAT1, upregulation of interferon-stimulated genes and persistent accumulation of cytosolic DNA, all of which are indicators for the activation of the T1IFN response. Furthermore, this did not require damage induction by ionizing radiation. Instead, our data revealed that production of reactive oxygen species (ROS) synergises with PNKP loss to potentiate the T1IFN response, and that loss of PNKP significantly compromises mitochondrial DNA (mtDNA) integrity. Depletion of mtDNA or treatment of PNKP-depleted cells with ROS scavengers abrogated the T1IFN response, implicating mtDNA as a significant source of the cytosolic DNA required to potentiate the T1IFN response. The STING signalling pathway is responsible for the observed increase in the pro-inflammatory gene signature in PNKP-depleted cells. While the response was dependent on ZBP1, cGAS only contributed to the response in some cell lines. Our data have implications for cancer therapy, since PNKP inhibitors would have the potential to stimulate the immune response, and also to the neurological disorders associated with PNKP mutation.
Asunto(s)
Enzimas Reparadoras del ADN , ADN Mitocondrial , Interferón Tipo I , Fosfotransferasas (Aceptor de Grupo Alcohol) , Radiación Ionizante , Especies Reactivas de Oxígeno , Humanos , Interferón Tipo I/metabolismo , Interferón Tipo I/genética , Fosfotransferasas (Aceptor de Grupo Alcohol)/genética , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Enzimas Reparadoras del ADN/metabolismo , Enzimas Reparadoras del ADN/genética , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Reparación del ADN , Factor de Transcripción STAT1/metabolismo , Factor de Transcripción STAT1/genética , Daño del ADN , Línea Celular , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Transducción de Señal , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Fosforilación , Citosol/metabolismo , Línea Celular Tumoral , Proteínas de Unión al ARN/metabolismo , Proteínas de Unión al ARN/genéticaRESUMEN
Immune checkpoint inhibitor (ICI)-induced myocarditis involves intensive immune/inflammation activation; however, its molecular basis is unclear. Here, we show that gasdermin-E (GSDME), a gasdermin family member, drives ICI-induced myocarditis. Pyroptosis mediated by GSDME, but not the canonical GSDMD, is activated in myocardial tissue of mice and cancer patients with ICI-induced myocarditis. Deficiency of GSDME in male mice alleviates ICI-induced cardiac infiltration of T cells, macrophages, and monocytes, as well as mitochondrial damage and inflammation. Restoration of GSDME expression specifically in cardiomyocytes, rather than myeloid cells, in GSDME-deficient mice reproduces ICI-induced myocarditis. Mechanistically, quantitative proteomics reveal that GSDME-dependent pyroptosis promotes cell death and mitochondrial DNA release, which in turn activates cGAS-STING signaling, triggering a robust interferon response and myocardial immune/inflammation activation. Pharmacological blockade of GSDME attenuates ICI-induced myocarditis and improves long-term survival in mice. Our findings may advance the understanding of ICI-induced myocarditis and suggest that targeting the GSDME-cGAS-STING-interferon axis may help prevent and manage ICI-associated myocarditis.