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1.
Int J Mol Sci ; 21(19)2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33019591

RESUMO

Tom70 is a versatile adaptor protein of 70 kDa anchored in the outer membrane of mitochondria in metazoa, fungi and amoeba. The tertiary structure was resolved for the Tom70 of yeast, showing 26 α-helices, most of them participating in the formation of 11 tetratricopeptide repeat (TPR) motifs. Tom70 serves as a docking site for cytosolic chaperone proteins and co-chaperones and is thereby involved in the uptake of newly synthesized chaperone-bound proteins in mitochondrial biogenesis. In yeast, Tom70 additionally mediates ER-mitochondria contacts via binding to sterol transporter Lam6/Ltc1. In mammalian cells, TOM70 promotes endoplasmic reticulum (ER) to mitochondria Ca2+ transfer by association with the inositol-1,4,5-triphosphate receptor type 3 (IP3R3). TOM70 is specifically targeted by the Bcl-2-related protein MCL-1 that acts as an anti-apoptotic protein in macrophages infected by intracellular pathogens, but also in many cancer cells. By participating in the recruitment of PINK1 and the E3 ubiquitin ligase Parkin, TOM70 can be implicated in the development of Parkinson's disease. TOM70 acts as receptor of the mitochondrial antiviral-signaling protein (MAVS) and thereby participates in the corresponding system of innate immunity against viral infections. The protein encoded by Orf9b in the genome of SARS-CoV-2 binds to TOM70, probably compromising the synthesis of type I interferons.


Assuntos
Imunidade Inata , Proteínas de Transporte da Membrana Mitocondrial/química , Animais , Betacoronavirus/genética , Sítios de Ligação , Humanos , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Fases de Leitura Aberta , Ligação Proteica , Transporte Proteico
2.
Proc Natl Acad Sci U S A ; 117(36): 22204-22213, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32848060

RESUMO

The peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) is a transcriptional coactivator that controls expression of metabolic/energetic genes, programming cellular responses to nutrient and environmental adaptations such as fasting, cold, or exercise. Unlike other coactivators, PGC-1α contains protein domains involved in RNA regulation such as serine/arginine (SR) and RNA recognition motifs (RRMs). However, the RNA targets of PGC-1α and how they pertain to metabolism are unknown. To address this, we performed enhanced ultraviolet (UV) cross-linking and immunoprecipitation followed by sequencing (eCLIP-seq) in primary hepatocytes induced with glucagon. A large fraction of RNAs bound to PGC-1α were intronic sequences of genes involved in transcriptional, signaling, or metabolic function linked to glucagon and fasting responses, but were not the canonical direct transcriptional PGC-1α targets such as OXPHOS or gluconeogenic genes. Among the top-scoring RNA sequences bound to PGC-1α were Foxo1, Camk1δ, Per1, Klf15, Pln4, Cluh, Trpc5, Gfra1, and Slc25a25 PGC-1α depletion decreased a fraction of these glucagon-induced messenger RNA (mRNA) transcript levels. Importantly, knockdown of several of these genes affected glucagon-dependent glucose production, a PGC-1α-regulated metabolic pathway. These studies show that PGC-1α binds to intronic RNA sequences, some of them controlling transcript levels associated with glucagon action.


Assuntos
Glucagon/metabolismo , Glucagon/farmacologia , Hepatócitos/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Células Cultivadas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/fisiologia , Gluconeogênese/fisiologia , Glucose/metabolismo , Guanosina Trifosfato/metabolismo , Fígado/metabolismo , Masculino , Metabolômica , Camundongos , Camundongos Endogâmicos C57BL , Proteínas de Transporte da Membrana Mitocondrial/genética , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Ligação Proteica , Transcriptoma
3.
Proc Natl Acad Sci U S A ; 117(35): 21731-21739, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32801213

RESUMO

Ca2+ uptake by mitochondria regulates bioenergetics, apoptosis, and Ca2+ signaling. The primary pathway for mitochondrial Ca2+ uptake is the mitochondrial calcium uniporter (MCU), a Ca2+-selective ion channel in the inner mitochondrial membrane. MCU-mediated Ca2+ uptake is driven by the sizable inner-membrane potential generated by the electron-transport chain. Despite the large thermodynamic driving force, mitochondrial Ca2+ uptake is tightly regulated to maintain low matrix [Ca2+] and prevent opening of the permeability transition pore and cell death, while meeting dynamic cellular energy demands. How this is accomplished is controversial. Here we define a regulatory mechanism of MCU-channel activity in which cytoplasmic Ca2+ regulation of intermembrane space-localized MICU1/2 is controlled by Ca2+-regulatory mechanisms localized across the membrane in the mitochondrial matrix. Ca2+ that permeates through the channel pore regulates Ca2+ affinities of coupled inhibitory and activating sensors in the matrix. Ca2+ binding to the inhibitory sensor within the MCU amino terminus closes the channel despite Ca2+ binding to MICU1/2. Conversely, disruption of the interaction of MICU1/2 with the MCU complex disables matrix Ca2+ regulation of channel activity. Our results demonstrate how Ca2+ influx into mitochondria is tuned by coupled Ca2+-regulatory mechanisms on both sides of the inner mitochondrial membrane.


Assuntos
Canais de Cálcio/metabolismo , Cálcio/metabolismo , Mitocôndrias/metabolismo , Apoptose , Transporte Biológico , Cálcio/fisiologia , Canais de Cálcio/fisiologia , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/fisiologia , Proteínas de Transporte de Cátions/metabolismo , Proteínas de Transporte de Cátions/fisiologia , Citoplasma/metabolismo , Citosol/metabolismo , Células HEK293 , Células HeLa , Humanos , Potencial da Membrana Mitocondrial/fisiologia , Mitocôndrias/fisiologia , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/fisiologia , Membranas Mitocondriais/metabolismo , Membranas Mitocondriais/fisiologia , Oxirredução , Multimerização Proteica , Transdução de Sinais
4.
Nat Commun ; 11(1): 3347, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620768

RESUMO

A sharp increase in mitochondrial Ca2+ marks the activation of brown adipose tissue (BAT) thermogenesis, yet the mechanisms preventing Ca2+ deleterious effects are poorly understood. Here, we show that adrenergic stimulation of BAT activates a PKA-dependent mitochondrial Ca2+ extrusion via the mitochondrial Na+/Ca2+ exchanger, NCLX. Adrenergic stimulation of NCLX-null brown adipocytes (BA) induces a profound mitochondrial Ca2+ overload and impaired uncoupled respiration. Core body temperature, PET imaging of glucose uptake and VO2 measurements confirm a thermogenic defect in NCLX-null mice. We show that Ca2+ overload induced by adrenergic stimulation of NCLX-null BAT, triggers the mitochondrial permeability transition pore (mPTP) opening, leading to a remarkable mitochondrial swelling and cell death. Treatment with mPTP inhibitors rescue mitochondrial function and thermogenesis in NCLX-null BAT, while calcium overload persists. Our findings identify a key pathway through which BA evade apoptosis during adrenergic stimulation of uncoupling. NCLX deletion transforms the adrenergic pathway responsible for thermogenesis activation into a death pathway.


Assuntos
Adipócitos Marrons/patologia , Tecido Adiposo Marrom/metabolismo , Norepinefrina/metabolismo , Trocador de Sódio e Cálcio/metabolismo , Termogênese/fisiologia , Adipócitos Marrons/citologia , Adipócitos Marrons/efeitos dos fármacos , Tecido Adiposo Marrom/citologia , Adrenérgicos/farmacologia , Animais , Apoptose/efeitos dos fármacos , Cálcio/metabolismo , Células Cultivadas , Temperatura Baixa/efeitos adversos , Ciclosporina/farmacologia , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/fisiologia , Feminino , Microscopia Intravital , Masculino , Camundongos , Camundongos Knockout , Microscopia de Fluorescência , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/antagonistas & inibidores , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Cultura Primária de Células , Transdução de Sinais , Trocador de Sódio e Cálcio/genética , Termogênese/efeitos dos fármacos
5.
Nat Commun ; 11(1): 3290, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620929

RESUMO

In mitochondria, ß-barrel outer membrane proteins mediate protein import, metabolite transport, lipid transport, and biogenesis. The Sorting and Assembly Machinery (SAM) complex consists of three proteins that assemble as a 1:1:1 complex to fold ß-barrel proteins and insert them into the mitochondrial outer membrane. We report cryoEM structures of the SAM complex from Myceliophthora thermophila, which show that Sam50 forms a 16-stranded transmembrane ß-barrel with a single polypeptide-transport-associated (POTRA) domain extending into the intermembrane space. Sam35 and Sam37 are located on the cytosolic side of the outer membrane, with Sam35 capping Sam50, and Sam37 interacting extensively with Sam35. Sam35 and Sam37 each adopt a GST-like fold, with no functional, structural, or sequence similarity to their bacterial counterparts. Structural analysis shows how the Sam50 ß-barrel opens a lateral gate to accommodate its substrates.


Assuntos
Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Membranas Mitocondriais/metabolismo , Biossíntese de Proteínas , Saccharomyces cerevisiae/metabolismo , Sequência de Aminoácidos , Microscopia Crioeletrônica , Detergentes/química , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Mitocôndrias/genética , Mitocôndrias/ultraestrutura , Proteínas de Transporte da Membrana Mitocondrial/química , Proteínas de Transporte da Membrana Mitocondrial/genética , Complexos Multiproteicos/química , Complexos Multiproteicos/metabolismo , Complexos Multiproteicos/ultraestrutura , Conformação Proteica , Dobramento de Proteína , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Homologia de Sequência de Aminoácidos , Sordariales/genética , Sordariales/metabolismo
6.
Anim Sci J ; 91(1): e13430, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32677174

RESUMO

Mitochondria are necessary for the transition from oocyte to embryo and for early embryonic development. Mitofusin 1 is the main mediator of mitochondrial fusion and homeostasis. We investigated Mitofusin 1 expression levels in porcine somatic cell nuclear transfer (SCNT) embryos. The rate of blastocyst formation in SCNT embryos was reduced significantly compared with that of parthenogenetic activation embryos. SCNT embryos showed significantly decreased Mitofusin 1 expression and mitochondrial membrane potential, while exhibiting increased reactive oxygen species and apoptosis. Mitochondrial functional changes were observed in the SCNT embryos and may be correlated with low levels of Mitofusin 1 to negatively affect development.


Assuntos
Apoptose/genética , Blastocisto , Embrião de Mamíferos/metabolismo , Desenvolvimento Embrionário/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Expressão Gênica/genética , Estudos de Associação Genética/veterinária , Potencial da Membrana Mitocondrial/genética , Proteínas de Transporte da Membrana Mitocondrial/genética , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Partenogênese/genética , Suínos/genética , Suínos/fisiologia , Animais , Células Cultivadas , Técnicas de Cultura Embrionária/veterinária , Fertilização In Vitro/veterinária , Técnicas de Transferência Nuclear/veterinária , Espécies Reativas de Oxigênio/metabolismo
8.
Biochim Biophys Acta Bioenerg ; 1861(10): 148250, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32569663

RESUMO

Duchenne muscular dystrophy (DMD) is a progressive skeletal muscle disease that is associated with severe cardiac complications in the late stages. Significant mitochondrial dysfunction is reportedly responsible for the development of cardiomyopathy with age. At the same time, adaptive changes in mitochondrial metabolism in cardiomyocytes were identified in the early stages of DMD. In this work, we evaluate the functioning of calcium transport systems (MCU and NCLX), and MPT pore in the heart mitochondria of young dystrophin-deficient mice. As compared to wild-type animals, heart mitochondria of mdx mice have been found to be more efficient both in respect to Ca2+ uniport and Na+-dependent Ca2+ efflux. The data obtained indicate that the increased rate of Ca2+ uptake by heart mitochondria of mdx mice may be due to an increase in the ratio of MCU and MCUb subunits. In turn, an increase in the rate of Ca2+ efflux from organelles in DMD may be the result of a significant increase in the level of NCLX. Moreover, the heart mitochondria of mdx mice were more resistant to MPT pore opening, which may be due to an increase in the microviscosity of mitochondrial membranes of DMD mice. At the same time, the level of putative MPT pore proteins did not change. The paper discusses the effect of rearrangements of the mitochondrial proteome involved in the transport and accumulation of calcium on the adaptation of this organ to DMD.


Assuntos
Cálcio/metabolismo , Mitocôndrias Cardíacas/metabolismo , Distrofia Muscular de Duchenne/metabolismo , Distrofia Muscular de Duchenne/patologia , Animais , Transporte Biológico , Regulação da Expressão Gênica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias Cardíacas/ultraestrutura , Proteínas de Transporte da Membrana Mitocondrial/química , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Miocárdio/patologia , Permeabilidade , Conformação Proteica , Trocador de Sódio e Cálcio/metabolismo
9.
Gene ; 754: 144854, 2020 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-32525045

RESUMO

Alzheimer's disease (AD) is one of the most common forms of neurodegenerative diseases. Aggregation of Aß42 and hyperphosphorylated tau are two major hallmarks of AD. Whether different forms of tau (soluble or hyperphosphorylated) or Aß are the main culprit in the events observed in AD is still under investigation. Here, we examined the effect of wild-type, prone to hyperphosphorylation and hyperphosphorylated tau, and also Aß42 peptide on the brain antioxidant defense system and two mitochondrial genes, Marf (homologous to human MFN2) and Drp1 involved in mitochondrial dynamics in transgenic Drosophila melanogaster. AD is an age associated disease. Therefore, the activity of antioxidant agents, CAT, SOD, and GSH levels and the mRNA levels of Marf and Drp1 were assessed in different time points of the flies lifespan. Reduction in cognitive function and antioxidant activity was observed in all transgenic flies at any time point. The most and the least effect on the eye phenotype was exerted by hyperphosphorylated tau and Aß42, respectively. In addition, the most remarkable alteration in Marf and Drp1 mRNA levels was observed in transgenic flies expressing hyperphosphorylated tau when pan neuronal expression of transgenes was applied. However, when the disease causing gene expression was confined to the mushroom body, Marf and Drp1 mRNA levels alteration was more prominent in tauWT and tauE14 transgenic flies, respectively. In conclusion, in spite of antioxidant deficiency caused by different types of tau and Aß42, it seems that tau exerts more toxic effect on the eye phenotype and mitochondrial genes regulation (Marf and Drp1). Moreover, different mechanisms seem to be involved in mitochondrial genes dysregulation when Aß or various forms of tau are expressed.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Animais Geneticamente Modificados/metabolismo , Drosophila melanogaster/metabolismo , Dinaminas/metabolismo , GTP Fosfo-Hidrolases/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , RNA Mensageiro/metabolismo , Proteínas tau/metabolismo , Animais , Animais Geneticamente Modificados/genética , Encéfalo/metabolismo , Drosophila melanogaster/genética , Dinaminas/genética , GTP Fosfo-Hidrolases/genética , Regulação da Expressão Gênica , Transtornos da Memória/metabolismo , Transtornos da Memória/patologia , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/genética , Fosforilação , RNA Mensageiro/genética , Proteínas tau/genética
10.
PLoS One ; 15(6): e0234653, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32579577

RESUMO

We previously demonstrated that hexokinase II (HK2) dissociation from mitochondria during cardiac ischemia correlates with cytochrome c (cyt-c) loss, oxidative stress and subsequent reperfusion injury. However, whether HK2 release is the primary signal mediating this ischemia-induced mitochondrial dysfunction was not established. To investigate this, we studied the effects of dissociating HK2 from isolated heart mitochondria. Mitochondria isolated from Langendorff-perfused rat hearts before and after 30 min global ischemia ± ischemic preconditioning (IPC) were subject to in vitro dissociation of HK2 by incubation with glucose-6-phosphate at pH 6.3. Prior HK2 dissociation from pre- or end-ischemic heart mitochondria had no effect on their cyt-c release, respiration (± ADP) or mitochondrial permeability transition pore (mPTP) opening. Inner mitochondrial membrane morphology was assessed indirectly by monitoring changes in light scattering (LS) and confirmed by transmission electron microscopy. Although no major ultrastructure differences were detected between pre- and end-ischemia mitochondria, the amplitude of changes in LS was reduced in the latter. This was prevented by IPC but not mimicked in vitro by HK2 dissociation. We also observed more Drp1, a mitochondrial fission protein, in end-ischemia mitochondria. IPC failed to prevent this increase but did decrease mitochondrial-associated dynamin 2. In vitro HK2 dissociation alone cannot replicate ischemia-induced effects on mitochondrial function implying that in vivo dissociation of HK2 modulates end-ischemia mitochondrial function indirectly perhaps involving interaction with mitochondrial fission proteins. The resulting changes in mitochondrial morphology and cristae structure would destabilize outer / inner membrane interactions, increase cyt-c release and enhance mPTP sensitivity to [Ca2+].


Assuntos
Hexoquinase/metabolismo , Mitocôndrias Cardíacas/enzimologia , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Isquemia Miocárdica/enzimologia , Animais , Respiração Celular/efeitos dos fármacos , Dinaminas/metabolismo , Glucose-6-Fosfato/farmacologia , Hemodinâmica/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Precondicionamento Isquêmico , Ligantes , Masculino , Mitocôndrias Cardíacas/efeitos dos fármacos , Mitocôndrias Cardíacas/ultraestrutura , Dinâmica Mitocondrial/efeitos dos fármacos , Membranas Mitocondriais/efeitos dos fármacos , Membranas Mitocondriais/metabolismo , Isquemia Miocárdica/patologia , Ligação Proteica/efeitos dos fármacos , Ratos Wistar
11.
J Med Chem ; 63(13): 7033-7051, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32506913

RESUMO

Mutations in the mitochondrial fusion protein mitofusin (MFN) 2 cause the chronic neurodegenerative condition Charcot-Marie-Tooth disease type 2A (CMT2A), for which there is currently no treatment. Small-molecule activators of MFN1 and MFN2 enhance mitochondrial fusion and offer promise as therapy for this condition, but prototype compounds have poor pharmacokinetic properties. Herein, we describe a rational design of a series of 6-phenylhexanamide derivatives whose pharmacokinetic optimization yielded a 4-hydroxycyclohexyl analogue, 13, with the potency, selectivity, and oral bioavailability of a preclinical candidate. Studies of 13 cis- and trans-4-hydroxycyclohexyl isostereomers unexpectedly revealed functionality and protein engagement exclusively for the trans form, 13B. Preclinical absorption, distribution, metabolism, and excretion (ADME) and in vivo target engagement studies of 13B support further development of 6-phenylhexanamide derivatives as therapeutic agents for human CMT2A.


Assuntos
Amidas/química , Amidas/farmacologia , Desenho de Fármacos , GTP Fosfo-Hidrolases/metabolismo , Doenças Mitocondriais/tratamento farmacológico , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Proteínas Mitocondriais/metabolismo , Amidas/farmacocinética , Amidas/uso terapêutico , Animais , Camundongos , Estereoisomerismo , Especificidade por Substrato , Distribuição Tecidual
12.
Nat Commun ; 11(1): 2592, 2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32444642

RESUMO

Mitochondrial aging, which results in mitochondrial dysfunction, is strongly linked to many age-related diseases. Aging is associated with mitochondrial enlargement and transport of cytosolic proteins into mitochondria. The underlying homeostatic mechanisms that regulate mitochondrial morphology and function, and their breakdown during aging, remain unclear. Here, we identify a mitochondrial protein trafficking pathway in Drosophila melanogaster involving the mitochondria-associated protein Dosmit. Dosmit induces mitochondrial enlargement and the formation of double-membraned vesicles containing cytosolic protein within mitochondria. The rate of vesicle formation increases with age. Vesicles originate from the outer mitochondrial membrane as observed by tracking Tom20 localization, and the process is mediated by the mitochondria-associated Rab32 protein. Dosmit expression level is closely linked to the rate of ubiquitinated protein aggregation, which are themselves associated with age-related diseases. The mitochondrial protein trafficking route mediated by Dosmit offers a promising target for future age-related mitochondrial disease therapies.


Assuntos
Citoplasma/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Proteínas com Ferro-Enxofre/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Proteínas Mitocondriais/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Fatores Etários , Animais , Animais Geneticamente Modificados , Proteínas do Citoesqueleto/metabolismo , Drosophila melanogaster/fisiologia , Proteínas de Ligação ao GTP/metabolismo , Regulação da Expressão Gênica , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Longevidade , Camundongos , Mitocôndrias/genética , Mitocôndrias/patologia , Domínios Proteicos , Transporte Proteico , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Vesículas Transportadoras/metabolismo , Proteínas Ubiquitinadas/metabolismo
13.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 28(2): 377-384, 2020 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-32319366

RESUMO

OBJECTIVE: To investigate the clinical and prognostic value of SLC25A12 in patients with acute myeloid leukemia (AML). METHODS: The expression levels of SLC25A12 in bone marrow or peripheral blood cells of AML patients and healthy people in two independent cohorts (n=46, n=290, respectively) were compared. Then it was assessed that the prognostic value of SLC25A12 expression in two independent AML study cohorts (n=163, n=329, respectively) by mean of integrated analysis of genomic, transcriptome, clinical and prognosis information. RESULTS: The expression of SLC25A12 in AML patients significantly increased as compared with that of healthy people (P=0.0001, P=0.0238, respectively). Univariate and multivariate analyze showed that high SLC25A12 expression was significantly associated with shorter event-free survival (EFS)(HR=1.605, P=0.018) and overall survival (OS)(HR=1.818, P=0.002) of patients. In favorable-risk and intermediate-risk subgroups, patients with high SLC25A12 expression showed shorter EFS and OS than patients with low SLC25A12 expression. CONCLUSION: High SLC25A12 expression significantly associated with poor prognosis of AML patients, which suggests that SLC25A12 aberrant expression can be used as a potential molecular marker for prognosis evaluation of AML patients.


Assuntos
Leucemia Mieloide Aguda , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Medula Óssea , Intervalo Livre de Doença , Humanos , Prognóstico , Transcriptoma
14.
Nature ; 580(7804): 542-547, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32322059

RESUMO

Prolonged mitosis often results in apoptosis1. Shortened mitosis causes tumorigenic aneuploidy, but it is unclear whether it also activates the apoptotic machinery2. Separase, a cysteine protease and trigger of all eukaryotic anaphases, has a caspase-like catalytic domain but has not previously been associated with cell death3,4. Here we show that human cells that enter mitosis with already active separase rapidly undergo death in mitosis owing to direct cleavage of anti-apoptotic MCL1 and BCL-XL by separase. Cleavage not only prevents MCL1 and BCL-XL from sequestering pro-apoptotic BAK, but also converts them into active promoters of death in mitosis. Our data strongly suggest that the deadliest cleavage fragment, the C-terminal half of MCL1, forms BAK/BAX-like pores in the mitochondrial outer membrane. MCL1 and BCL-XL are turned into separase substrates only upon phosphorylation by NEK2A. Early mitotic degradation of this kinase is therefore crucial for preventing apoptosis upon scheduled activation of separase in metaphase. Speeding up mitosis by abrogation of the spindle assembly checkpoint results in a temporal overlap of the enzymatic activities of NEK2A and separase and consequently in cell death. We propose that NEK2A and separase jointly check on spindle assembly checkpoint integrity and eliminate cells that are prone to chromosome missegregation owing to accelerated progression through early mitosis.


Assuntos
Apoptose , Mitose , Separase/metabolismo , Animais , Linhagem Celular , Sobrevivência Celular , Segregação de Cromossomos , Humanos , Pontos de Checagem da Fase M do Ciclo Celular , Camundongos , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/química , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Quinases Relacionadas a NIMA/metabolismo , Fosforilação , Especificidade por Substrato , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteína bcl-X/metabolismo
15.
Am J Chin Med ; 48(3): 679-702, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32329644

RESUMO

Autophagy is a process of active programmed cell death, where a dying cell induces autophagosomes and subsequently regulated by degradative machinery. The aim of this study was to investigate the mechanism behind induction of autophagic cell death by Naringin flavonoid in AGS cancer cells. Growth inhibition of AGS cells showed downregulation of PI3K/Akt/mTOR signaling by Naringin treatment. Transmission electron microscopy observation showed swollen mitochondria and lysosome near peri-nuclear zone fused with autophagic vacuoles. Rapamycin pre-treatment with Naringin showed significant decrease in mTOR phosphorylation and increase in LC3B activation in AGS cells. Decrease in mTOR phosphorylation is associated with lysosomal function activation was observed by time-dependent treatment of Naringin. Induction of lysosomal membrane permeabilization (LMP) was observed by LAMP1 activation leading lysosomal cell death by releasing Cathepsin D from lysosomal lumen to cytosol. Naringin treated AGS cells showed up-regulating BH3 domain Bad, down-regulating Bcl-xL, and Bad phosphorylation and significant mitochondrial fluorescence intensity expression. Significant localization of mitochondria and LC3B activation was examined by person coefficient correlation. Activation of ERK1/2-p38 MAPKs and production of intracellular ROS has been observed over Naringin treatment. It has also been elucidated that pre-treatment with NAC inhibited mitochondria-LC3B colocalization, where ROS acted as upstream of ERK1/2-p38 MAPKs activation. Lysosomal cell death involvement has been evaluated by BAF A1 pre-treatment, inhibiting LAMP1, Cathepsin D, ROS, and blocking autophagolysosome in AGS cell death. Taken together, these findings show that, Naringin induced autophagy cell death involves LMP mediated lysosomal damage and BH3 protein Bad activation in AGS cancer cells.


Assuntos
Autofagia/efeitos dos fármacos , Flavanonas/farmacologia , Lisossomos/patologia , Neoplasias Gástricas/patologia , Permeabilidade da Membrana Celular/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Humanos , Lisossomos/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo , Células Tumorais Cultivadas
16.
Cardiovasc Drugs Ther ; 34(3): 303-310, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32236860

RESUMO

PURPOSE: The melatonin receptor (MT) agonist ramelteon has a higher affinity to MT1 than for MT2 receptors and induces cardioprotection by involvement of mitochondrial potassium channels. Activation of mitochondrial potassium channels leads to release of free radicals. We investigated whether (1) ramelteon-induced cardioprotection is MT2 receptor specific and (2) if free radicals are involved in ramelteon-induced cardioprotection. METHODS: Hearts of male Wistar rats were randomized, placed on a Langendorff system, and perfused with Krebs-Henseleit buffer at a constant pressure of 80 mmHg. All hearts were subjected to 33 min of global ischemia and 60 min of reperfusion. Before ischemia hearts were perfused with ramelteon (Ram) with or without the MT2 receptor inhibitor 4-phenyl-2-propionamidotetralin (4P-PDOT+Ram, 4P-PDOT). In subsequent experiments, ramelteon was administered together with the radical oxygen species (ROS) scavenger N-2-mercaptopropionylglycine (MPG+Ram). To determine whether the blockade of ramelteon-induced cardioprotection can be restored, we combined ramelteon and MPG with mitochondrial permeability transition pore (mPTP) inhibitor cyclosporine A (CsA) at different time points. Infarct size was determined by triphenyltetrazolium chloride (TTC) staining. RESULTS: Ramelteon-induced infarct size reduction was completely blocked by 4P-PDOT and MPG. Ramelteon and MPG combined with CsA before ischemia were not cardioprotective but CsA at the onset of reperfusion could restore infarct size reduction. CONCLUSIONS: This study shows for the first time that despite the higher affinity to MT1 receptors, (1) ramelteon-induced cardioprotection involves MT2 receptors, (2) cardioprotection requires ROS release, and (3) inhibition of the mPTP can restore infarct size reduction.


Assuntos
Fármacos Cardiovasculares/farmacologia , Indenos/farmacologia , Mitocôndrias Cardíacas/efeitos dos fármacos , Infarto do Miocárdio/prevenção & controle , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Miócitos Cardíacos/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Receptor MT2 de Melatonina/agonistas , Animais , Modelos Animais de Doenças , Preparação de Coração Isolado , Masculino , Mitocôndrias Cardíacas/metabolismo , Mitocôndrias Cardíacas/patologia , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Infarto do Miocárdio/fisiopatologia , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Ratos Wistar , Receptor MT2 de Melatonina/metabolismo , Transdução de Sinais , Função Ventricular Esquerda/efeitos dos fármacos
17.
J Mol Biol ; 432(10): 3326-3337, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32277989

RESUMO

In the intermembrane space (IMS) of mitochondria, the receptor domain of Tim23 has an essential role during translocation of hundreds of different proteins from the cytosol via the TOM and TIM23 complexes in the outer and inner membranes, respectively. This intrinsically disordered domain, which can even extend into the cytosol, was shown, mostly in vitro, to interact with several subunits of the TOM and TIM23 complexes. To obtain molecular understanding of this organizational hub in the IMS, we dissected the IMS domain of Tim23 in vivo. We show that the interaction surface of Tim23 with Tim50 is larger than previously thought and reveal an unexpected interaction of Tim23 with Pam17 in the IMS, impairment of which influences their interaction in the matrix. Furthermore, mutations of two conserved negatively charged residues of Tim23, close to the inner membrane, prevented dimerization of Tim23. The same mutations increased exposure of Tim23 on the mitochondrial surface, whereas dissipation of membrane potential decreased it. Our results reveal an intricate network of Tim23 interactions in the IMS, whose influence is transduced across two mitochondrial membranes, ensuring efficient translocation of proteins into mitochondria.


Assuntos
Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/química , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Mutação , Sítios de Ligação , Proteínas de Transporte da Membrana Mitocondrial/genética , Modelos Moleculares , Ligação Proteica , Domínios Proteicos , Transporte Proteico , Desdobramento de Proteína
18.
Med Sci Monit ; 26: e918216, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32129321

RESUMO

BACKGROUND Chemoresistance is a primary hindrance for current cancer treatments. The influence of abnormal mitochondria in chemotherapy resistance is not well known. To explore the correlation between mitochondria and acquired chemoresistance, this work studied alterations in mitochondrial dynamics, biogenesis, and functions for paclitaxel-resistant cancer cell line A549/Taxol and its parental line A549. MATERIAL AND METHODS Mitochondrial morphology was observed by transmission electron microscopy and confocal microscopy. We measured the mitochondrial mass and mitochondrial membrane potential using fluorescent dyes. The glucose metabolic profile and ATP (adenosine triphosphate) content were determined by bioluminescent cell assays. Seahorse bio-energy analyzer XF24 was used to detect the mitochondrial respiratory function. The expressions of mitochondrial dynamics and biogenesis related genes were quantified using real-time polymerase chain reaction. RESULTS We observed fusion morphology of the mitochondrial network in A549/Taxol cells, with upregulation of fusion genes (Mfn1 and Mfn2) and downregulation of fission gene Fis1. In A549/Taxol cells, mitochondrial mass showed a significant decrease, while the mitochondrial biogenesis pathway was strongly activated. Despite the decreased mitochondrial membrane potential, the capability for mitochondrial respiration was not impaired in A549/Taxol cells. CONCLUSIONS Our study revealed a series changes of mitochondrial characteristics in paclitaxel-resistant cells. Mfn1 and Mfn2 and PGC-1alpha increased, while Fis1 expression and mitochondrial oxidative phosphorylation decreased in A549/Taxol cell lines. These changes to mitochondrial fusion, fission, and biological function contributed to the occurrence of paclitaxel resistance in tumor cells which induced paclitaxel resistance.


Assuntos
Resistencia a Medicamentos Antineoplásicos , Dinâmica Mitocondrial , Biogênese de Organelas , Paclitaxel/farmacologia , Células A549 , GTP Fosfo-Hidrolases/metabolismo , Humanos , Potencial da Membrana Mitocondrial , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Mitocôndrias/ultraestrutura , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Proteínas Mitocondriais/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo
19.
Oxid Med Cell Longev ; 2020: 6431517, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32215175

RESUMO

Diabetic kidney disease (DKD) has become the leading cause of end-stage renal disease worldwide. Renal tubular epithelial cell apoptosis and tubular atrophy have been recognized as indicators of the severity and progression of DKD, while the mechanism remains elusive. Tumor necrosis factor receptor-associated protein 1 (TRAP1) plays critical roles in apoptosis. The aim of this study was to investigate the protective role TRAP1 plays in DKD and to study the potential underlying mechanisms. TRAP1 expression was decreased, and mitochondria were injured in NRK-52e cells under high-glucose (HG) conditions. The overexpression of TRAP1 ameliorated HG-induced apoptosis, increased cell viability, maintained mitochondrial morphology, adenosine triphosphate (ATP) levels, and mitochondrial membrane potential (MMP), and buffered oxidative stress, whereas TRAP1 knockdown aggravated these effects. The protective effects of TRAP1 may be exerted via the inhibition of mitochondrial permeability transition pore (mPTP) opening, and the damage caused by TRAP1 knockdown can be partially reversed by treatment with the mPTP opening inhibitor cyclosporin A (CsA). In vivo, TRAP1 expression upregulation by AAV2/9 injection prevented renal dysfunction, ameliorated histopathological changes, maintained mitochondrial morphology and function, and reduced apoptosis and reactive oxygen species (ROS) in STZ-treated DKD rats. Thus, our results suggest that TRAP1 ameliorates diabetes-induced renal injury by preventing abnormal mPTP opening and maintaining mitochondrial structure and function, which may be treated as a potential target for DKD treatment.


Assuntos
Nefropatias Diabéticas/prevenção & controle , Glucose/efeitos adversos , Proteínas de Choque Térmico HSP90/metabolismo , Mitocôndrias/patologia , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Apoptose , Linhagem Celular , Sobrevivência Celular , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Expressão Gênica , Glucose/metabolismo , Proteínas de Choque Térmico HSP90/genética , Masculino , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Ratos , Ratos Sprague-Dawley
20.
Cell Physiol Biochem ; 54(2): 211-229, 2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-32100973

RESUMO

BACKGROUND/AIMS: Mitochondrial ATP synthase, in addition to being involved in ATP synthesis, is involved in permeability transition pore (PTP) formation, which precedes apoptosis in mammalian cells and programmed cell death in yeast. Mutations in genes encoding ATP synthase subunits cause neuromuscular disorders and have been identified in cancer samples. PTP is also involved in pathology. We previously found that in Saccharomyces cerevisiae, two mutations in ATP synthase subunit a (atp6-P163S and atp6-K90E, equivalent to those detected in prostate and thyroid cancer samples, respectively) in the OM45-GFP background affected ROS and calcium homeostasis and delayed yeast PTP (yPTP) induction upon calcium treatment by modulating the dynamics of ATP synthase dimer/oligomer formation. The Om45 protein is a component of the porin complex, which is equivalent to mammalian VDAC. We aimed to investigate yPTP function in atp6-P163S and atp6-K90E mutants lacking the e and g dimerization subunits of ATP synthase. METHODS: Triple mutants with the atp6-P163S or atp6-K90E mutation, the OM45-GFP gene and deletion of the TIM11 gene encoding subunit e were constructed by crossing and tetrad dissection. In spores capable of growing, the original atp6 mutations reverted to wild type, and two compensatory mutations, namely, atp6-C33S-T215C, were selected. The effects of these mutations on cellular physiology, mitochondrial morphology, bioenergetics and permeability transition (PT) were analyzed by fluorescence and electron microscopy, mitochondrial respiration, ATP synthase activity, calcium retention capacity and swelling assays. RESULTS: The atp6-C33S-T215C mutations in the OM45-GFP background led to delayed growth at elevated temperature on both fermentative and respiratory media and increased sensitivity to high calcium ions concentration or hydrogen peroxide in the medium. The ATP synthase activity was reduced by approximately 50% and mitochondrial network was hyperfused in these cells grown at elevated temperature. The atp6-C33S-T215C stabilized ATP synthase dimers and restored the yPTP properties in Tim11∆ cells. In OM45-GFP cells, in which Tim11 is present, these mutations increased the fraction of swollen mitochondria by up to 85% vs 60% in the wild type, although the time required for calcium release doubled. CONCLUSION: ATP synthase subunit e is essential in the S. cerevisiae atp6-P163S and atp6-K90E mutants. In addition to subunits e and g, subunit a is critical for yPTP induction and conduction. The increased yPTP conduction decrease the S. cerevisiae cell fitness.


Assuntos
Proteínas de Transporte da Membrana Mitocondrial/metabolismo , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Cálcio/metabolismo , Cobre/farmacologia , DNA Mitocondrial/metabolismo , Dimerização , Peróxido de Hidrogênio/farmacologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/efeitos dos fármacos , ATPases Mitocondriais Próton-Translocadoras/química , ATPases Mitocondriais Próton-Translocadoras/genética , Mutagênese , Estrutura Quaternária de Proteína , Subunidades Proteicas/química , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Temperatura
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