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1.
EMBO J ; 29(7): 1272-84, 2010 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-20186124

RESUMO

Tetraploidy can constitute a metastable intermediate between normal diploidy and oncogenic aneuploidy. Here, we show that the absence of p53 is not only permissive for the survival but also for multipolar asymmetric divisions of tetraploid cells, which lead to the generation of aneuploid cells with a near-to-diploid chromosome content. Multipolar mitoses (which reduce the tetraploid genome to a sub-tetraploid state) are more frequent when p53 is downregulated and the product of the Mos oncogene is upregulated. Mos inhibits the coalescence of supernumerary centrosomes that allow for normal bipolar mitoses of tetraploid cells. In the absence of p53, Mos knockdown prevents multipolar mitoses and exerts genome-stabilizing effects. These results elucidate the mechanisms through which asymmetric cell division drives chromosomal instability in tetraploid cells.


Assuntos
Carcinoma/metabolismo , Neoplasias do Colo/metabolismo , Genes mos , Mitose , Poliploidia , Proteína Supressora de Tumor p53/metabolismo , Aneuploidia , Animais , Carcinoma/genética , Linhagem Celular Tumoral , Centrossomo/metabolismo , Instabilidade Cromossômica , Neoplasias do Colo/genética , Feminino , Deleção de Genes , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos , Camundongos Nus , Proteína Supressora de Tumor p53/genética
2.
JOP ; 15(4): 308-9, 2014 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-25076328

RESUMO

Pancreatic adenocarcinoma is a highly aggressive cancer, with a median patient survival of less than one year. Clinically useful biomarkers capable of accurately assessing prognosis, as well as response to therapy, are urgently needed. At the 2014 ASCO Annual Meeting, Maus et al. (Abstract #e15199) and Neuzillet et al. (Abstract #e15200) present data on use of c-met as a prognostic biomarker, and Shultz et al. (Abstract #4133) use a multiplex antibody panel to identify predictive markers of response to gemcitabine and erlotinib.


Assuntos
Adenocarcinoma/metabolismo , Biomarcadores Tumorais/metabolismo , Neoplasias Pancreáticas/metabolismo , Adenocarcinoma/sangue , Adenocarcinoma/genética , Biomarcadores Tumorais/sangue , Biomarcadores Tumorais/genética , Antígeno Carcinoembrionário/sangue , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/sangue , Neoplasias Pancreáticas/sangue , Neoplasias Pancreáticas/genética , Prognóstico , Proteínas Proto-Oncogênicas c-met/genética , Proteínas Proto-Oncogênicas c-met/metabolismo , Análise de Sobrevida
3.
EMBO J ; 28(5): 578-90, 2009 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-19165151

RESUMO

Dying tumour cells can elicit a potent anticancer immune response by exposing the calreticulin (CRT)/ERp57 complex on the cell surface before the cells manifest any signs of apoptosis. Here, we enumerate elements of the pathway that mediates pre-apoptotic CRT/ERp57 exposure in response to several immunogenic anticancer agents. Early activation of the endoplasmic reticulum (ER)-sessile kinase PERK leads to phosphorylation of the translation initiation factor eIF2alpha, followed by partial activation of caspase-8 (but not caspase-3), caspase-8-mediated cleavage of the ER protein BAP31 and conformational activation of Bax and Bak. Finally, a pool of CRT that has transited the Golgi apparatus is secreted by SNARE-dependent exocytosis. Knock-in mutation of eIF2alpha (to make it non-phosphorylatable) or BAP31 (to render it uncleavable), depletion of PERK, caspase-8, BAP31, Bax, Bak or SNAREs abolished CRT/ERp57 exposure induced by anthracyclines, oxaliplatin and ultraviolet C light. Depletion of PERK, caspase-8 or SNAREs had no effect on cell death induced by anthracyclines, yet abolished the immunogenicity of cell death, which could be restored by absorbing recombinant CRT to the cell surface.


Assuntos
Antineoplásicos/farmacologia , Calreticulina/fisiologia , Morte Celular/imunologia , Retículo Endoplasmático/metabolismo , Antraciclinas/imunologia , Antraciclinas/farmacologia , Antineoplásicos/imunologia , Apoptose , Caspase 3/metabolismo , Caspase 8/metabolismo , Linhagem Celular , Fator de Iniciação 2 em Eucariotos/metabolismo , Exocitose , Complexo de Golgi/metabolismo , Humanos , Proteínas de Membrana/metabolismo , Compostos Organoplatínicos/imunologia , Compostos Organoplatínicos/farmacologia , Oxaliplatina , Fosforilação , Proteínas SNARE/metabolismo , Raios Ultravioleta , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteína X Associada a bcl-2/metabolismo , eIF-2 Quinase/metabolismo
4.
Hum Mol Genet ; 19(6): 987-1000, 2010 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-20026556

RESUMO

Human Wolf-Hirschhorn syndrome (WHS) is a multigenic disorder resulting from a hemizygous deletion on chromosome 4. LETM1 is the best candidate gene for seizures, the strongest haploinsufficiency phenotype of WHS patients. Here, we identify the Drosophila gene CG4589 as the ortholog of LETM1 and name the gene DmLETM1. Using RNA interference approaches in both Drosophila melanogaster cultured cells and the adult fly, we have assayed the effects of down-regulating the LETM1 gene on mitochondrial function. We also show that DmLETM1 complements growth and mitochondrial K(+)/H(+) exchange (KHE) activity in yeast deficient for LETM1. Genetic studies allowing the conditional inactivation of LETM1 function in specific tissues demonstrate that the depletion of DmLETM1 results in roughening of the adult eye, mitochondrial swelling and developmental lethality in third-instar larvae, possibly the result of deregulated mitophagy. Neuronal specific down-regulation of DmLETM1 results in impairment of locomotor behavior in the fly and reduced synaptic neurotransmitter release. Taken together our results demonstrate the function of DmLETM1 as a mitochondrial osmoregulator through its KHE activity and uncover a pathophysiological WHS phenotype in the model organism D. melanogaster.


Assuntos
Antiporters/genética , Proteínas de Ligação ao Cálcio/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Mutação/genética , Convulsões/complicações , Convulsões/genética , Síndrome de Wolf-Hirschhorn/complicações , Síndrome de Wolf-Hirschhorn/genética , Sequência de Aminoácidos , Animais , Antiporters/química , Antiporters/metabolismo , Proteínas de Ligação ao Cálcio/química , Proteínas de Ligação ao Cálcio/metabolismo , Regulação para Baixo , Proteínas de Drosophila/química , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/ultraestrutura , Olho/patologia , Olho/ultraestrutura , Técnicas de Silenciamento de Genes , Teste de Complementação Genética , Humanos , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Proteínas Mitocondriais/química , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Dados de Sequência Molecular , Atividade Motora/fisiologia , Sistema Nervoso/patologia , Sistema Nervoso/fisiopatologia , Sistema Nervoso/ultraestrutura , Neurotransmissores/metabolismo , Especificidade de Órgãos , Interferência de RNA , Saccharomyces cerevisiae/metabolismo , Homologia de Sequência de Aminoácidos , Sinapses/metabolismo , Sinapses/ultraestrutura
5.
Curr Opin Immunol ; 20(5): 504-11, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18573340

RESUMO

Physiological cell death, which occurs as a continuous byproduct of cellular turnover, is non-immunogenic or even tolerogenic, thereby avoiding autoimmunity. By contrast, cancer cell death elicited by radiotherapy and some chemotherapeutic agents such as anthracyclines is immunogenic. Recent data suggest that innate and cognate immune responses elicited by such anti-cancer agents are required for an optimal therapeutic outcome, underscoring the clinical relevance of immunogenic cell death. Here we discuss the concept that immunogenic death involves changes in the composition of the cell surface, as well as the release of soluble immunogenic signals that occur in a defined temporal sequence. This 'key' then operates on a series of receptors expressed by dendritic cells (DC, the 'lock') to allow for the presentation of tumor antigens to T cells and for the initiation of a productive immune response. Immunogenic cell death is characterized by the early cell surface exposure of chaperones including calreticulin and/or heat shock proteins, which determine the uptake of tumor antigens and/or affect DC maturation. Moreover, the late release of High mobility group box 1 (HMGB1), which acts on toll-like receptor 4 (TLR4), is required for optimal presentation of antigens from dying tumor cells. Nonetheless, numerous details on the molecular events that define immunogenicity remain to be defined, both at the level of the dying cancer cells and at the level of the responding innate effectors.


Assuntos
Antígenos de Neoplasias/imunologia , Apoptose/imunologia , Células Dendríticas/imunologia , Neoplasias/imunologia , Linfócitos T/imunologia , Receptor 4 Toll-Like/metabolismo , Animais , Antígenos de Neoplasias/metabolismo , Calreticulina/imunologia , Calreticulina/metabolismo , Células Dendríticas/metabolismo , Proteína HMGB1/imunologia , Proteína HMGB1/metabolismo , Proteínas de Choque Térmico/imunologia , Proteínas de Choque Térmico/metabolismo , Humanos , Ativação Linfocitária/imunologia , Camundongos , Neoplasias/patologia , Linfócitos T/metabolismo , Receptor 4 Toll-Like/imunologia
6.
Nat Cell Biol ; 6(3): 215-26, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15039780

RESUMO

During the development of multicellular organisms, concerted actions of molecular signalling networks determine whether cells undergo proliferation, differentiation, death or ageing. Here we show that genetic inactivation of the stress signalling kinase, MKK7, a direct activator of JNKs in mice, results in embryonic lethality and impaired proliferation of hepatocytes. Beginning at passage 4-5, mkk7(-/-) mouse embryonic fibroblasts (MEFs) display impaired proliferation, premature senescence and G2/M cell cycle arrest. Similarly, loss of c-Jun or expression of a c-JunAA mutant in which the JNK phosphorylation sites were replaced with alanine results in a G2/M cell-cycle block. The G2/M cell-cycle kinase CDC2 was identified as a target for the MKK7-JNK-c-Jun pathway. These data show that the MKK7-JNK-c-Jun signalling pathway couples developmental and environmental cues to CDC2 expression, G2/M cell cycle progression and cellular senescence in fibroblasts.


Assuntos
Senescência Celular/genética , Fase G2/genética , Hepatócitos/enzimologia , Quinases de Proteína Quinase Ativadas por Mitógeno/deficiência , Mitose/genética , Estresse Fisiológico/enzimologia , Animais , Proteína Quinase CDC2/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Células Cultivadas , Feto , Fibroblastos/citologia , Fibroblastos/enzimologia , Genes Letais/genética , Hepatócitos/citologia , Proteínas Quinases JNK Ativadas por Mitógeno , Fígado/anormalidades , Fígado/patologia , MAP Quinase Quinase 7 , Sistema de Sinalização das MAP Quinases/genética , Camundongos , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mutação/genética , Fosforilação , Proteínas Proto-Oncogênicas c-jun/deficiência , Proteínas Proto-Oncogênicas c-jun/genética , Estresse Fisiológico/genética
7.
Neuron ; 43(5): 715-28, 2004 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-15339652

RESUMO

Circadian rhythms of physiology and behavior are generated by biological clocks that are synchronized to the cyclic environment by photic or nonphotic cues. The interactions and integration of various entrainment pathways to the clock are poorly understood. Here, we show that the Ras-like G protein Dexras1 is a critical modulator of the responsiveness of the master clock to photic and nonphotic inputs. Genetic deletion of Dexras1 reduces photic entrainment by eliminating a pertussis-sensitive circadian response to NMDA. Mechanistically, Dexras1 couples NMDA and light input to Gi/o and ERK activation. In addition, the mutation greatly potentiates nonphotic responses to neuropeptide Y and unmasks a nonphotic response to arousal. Thus, Dexras1 modulates the responses of the master clock to photic and nonphotic stimuli in opposite directions. These results identify a signaling molecule that serves as a differential modulator of the gated photic and nonphotic input pathways to the circadian timekeeping system.


Assuntos
Relógios Biológicos/genética , Ritmo Circadiano/genética , Proteínas de Ligação ao GTP/fisiologia , Células Ganglionares da Retina/metabolismo , Núcleo Supraquiasmático/metabolismo , Vias Visuais/metabolismo , Proteínas ras/fisiologia , Animais , Relógios Biológicos/efeitos da radiação , Ritmo Circadiano/efeitos da radiação , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/metabolismo , Proteínas de Ligação ao GTP/genética , Ácido Glutâmico/metabolismo , Luz , Transdução de Sinal Luminoso/efeitos dos fármacos , Transdução de Sinal Luminoso/genética , Camundongos , Camundongos Knockout , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mutação/genética , Neuropeptídeo Y/metabolismo , Toxina Pertussis/farmacologia , Estimulação Luminosa , Receptores de N-Metil-D-Aspartato/metabolismo , Células Ganglionares da Retina/citologia , Células Ganglionares da Retina/efeitos da radiação , Núcleo Supraquiasmático/citologia , Núcleo Supraquiasmático/efeitos da radiação , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/genética , Vias Visuais/citologia , Vias Visuais/efeitos da radiação , Proteínas ras/genética
8.
Mol Cell Biol ; 25(23): 10261-72, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16287843

RESUMO

Cardiac and skeletal muscle critically depend on mitochondrial energy metabolism for their normal function. Recently, we showed that apoptosis-inducing factor (AIF), a mitochondrial protein implicated in programmed cell death, plays a role in mitochondrial respiration. However, the in vivo consequences of AIF-regulated mitochondrial respiration resulting from a loss-of-function mutation in Aif are not known. Here, we report tissue-specific deletion of Aif in the mouse. Mice in which Aif has been inactivated specifically in cardiac and skeletal muscle exhibit impaired activity and protein expression of respiratory chain complex I. Mutant animals develop severe dilated cardiomyopathy, heart failure, and skeletal muscle atrophy accompanied by lactic acidemia consistent with defects in the mitochondrial respiratory chain. Isolated hearts from mutant animals exhibit poor contractile performance in response to a respiratory chain-dependent energy substrate, but not in response to glucose, supporting the notion that impaired heart function in mutant animals results from defective mitochondrial energy metabolism. These data provide genetic proof that the previously defined cell death promoter AIF has a second essential function in mitochondrial respiration and aerobic energy metabolism required for normal heart function and skeletal muscle homeostasis.


Assuntos
Fator de Indução de Apoptose/deficiência , Fator de Indução de Apoptose/metabolismo , Cardiomiopatia Dilatada/patologia , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Atrofia Muscular/patologia , Animais , Fator de Indução de Apoptose/genética , Biomarcadores , Cardiomiopatia Dilatada/embriologia , Cardiomiopatia Dilatada/genética , Cardiomiopatia Dilatada/metabolismo , Embrião de Mamíferos/embriologia , Embrião de Mamíferos/metabolismo , Embrião de Mamíferos/patologia , Glucose/metabolismo , Camundongos , Camundongos Transgênicos , Atrofia Muscular/embriologia , Atrofia Muscular/genética , Atrofia Muscular/metabolismo , Mutação/genética , Estresse Oxidativo
9.
Trends Genet ; 18(3): 142-9, 2002 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11858838

RESUMO

Programmed cell death is used by multicellular organisms to eliminate excess, damaged or harmful cells. This process of cell suicide, defined in morphological terms as apoptosis, is crucial for developmental morphogenesis, tissue homeostasis and defense against pathogens. Over the past decade, our understanding of the genetic basis of the cell death machinery has grown exponentially using genetically modified organisms. In particular, inactivation of genes involved in cell death using homologous recombination in mice has provided an invaluable tool to understand the mechanisms, as well as the structural and functional consequences, of programmed cell death in mammals. This review discusses recent insights into the cellular death program as revealed by these mutant animals.


Assuntos
Apoptose/genética , Animais , Humanos , Camundongos , Camundongos Knockout , Neurônios/fisiologia , Receptores do Fator de Necrose Tumoral/fisiologia , Transdução de Sinais/fisiologia
10.
Ann N Y Acad Sci ; 1171: 2-11, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19723031

RESUMO

Since its discovery nearly a decade ago, apoptosis-inducing factor (AIF) has had anything but a staid and uneventful existence. AIF was originally described as a mitochondrial intermembrane protein that, after apoptosis induction, can translocate to the nucleus and trigger chromatin condensation and DNA fragmentation. Over the years, an AIF-mediated caspase-independent cell death pathway has been defined. Rather than functioning as a general component of the cell death machinery, AIF is required for specific cell death pathways, including lethal responses to excitotoxins such as N-methyl-D-aspartate and glutamate, the DNA-alkylating agent N-methyl-N'-nitro-N-nitroso-guanidine, hypoxia-ischemia, or growth factor deprivation. Also, important roles of AIF in mitochondrial metabolism and redox control, and more recently in obesity and diabetes, have been discovered. Much of our knowledge has come from studies of AIF orthologs in model organisms, Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, and mice, which have also highlighted the importance of AIF in animal physiology and human pathology. Here, we discuss the manifold nature of AIF in cell life and death, with particular emphasis of its roles in vivo.


Assuntos
Fator de Indução de Apoptose/metabolismo , Apoptose/fisiologia , Núcleo Celular/metabolismo , Mitocôndrias/metabolismo , Transdução de Sinais/fisiologia , Animais , Apoptose/genética , Fator de Indução de Apoptose/genética , Humanos , Modelos Biológicos , Mutação , Transporte Proteico , Transdução de Sinais/genética
11.
Cell Cycle ; 8(9): 1380-5, 2009 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-19342895

RESUMO

Tetraploidy may constitute a metastable state leading to numeric and structural chromosome abnormalities that are associated with cancer. Here, we show that cultured primary p53(-/-) (but not wild type, WT) mouse mammary epithelial cells (MMECs) accumulate a tetraploid sub-population in vitro. This occurs spontaneously, yet can be exacerbated by the addition of microtubule inhibitors as well as of inhibitors of cytokinesis. As compared to WT cells, tetraploid p53(-/-) MMECs contain supernumerary centrosomes and exhibit a reduced propensity to initiate the mitochondrial pathway of apoptosis. Moreover, tetraploid p53(-/-) MMECs are more resistant against anthracyclin-induced cell killing than their diploid counterparts. Altogether, these data indicate that p53 normally suppresses the generation of tetraploid cells, presumably by activating the intrinsic pathway of apoptosis. In the absence of p53, tetraploid cells accumulate as a result of inhibited apoptosis, which contributes to the acquisition of chemotherapy resistance.


Assuntos
Apoptose , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Glândulas Mamárias Animais/citologia , Poliploidia , Proteína Supressora de Tumor p53/metabolismo , Animais , Morte Celular , Linhagem da Célula , Células Cultivadas , Centrossomo/metabolismo , Camundongos , Camundongos Endogâmicos C57BL
12.
Biochem Soc Trans ; 36(Pt 5): 786-90, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18793137

RESUMO

Macroautophagy, often referred to as autophagy, designates the process by which portions of the cytoplasm, intracellular organelles and long-lived proteins are engulfed in double-membraned vacuoles (autophagosomes) and sent for lysosomal degradation. Basal levels of autophagy contribute to the maintenance of intracellular homoeostasis by ensuring the turnover of supernumerary, aged and/or damaged components. Under conditions of starvation, the autophagic pathway operates to supply cells with metabolic substrates, and hence represents an important pro-survival mechanism. Moreover, autophagy is required for normal development and for the protective response to intracellular pathogens. Conversely, uncontrolled autophagy is associated with a particular type of cell death (termed autophagic, or type II) that is characterized by the massive accumulation of autophagosomes. Regulators of apoptosis (e.g. Bcl-2 family members) also modulate autophagy, suggesting an intimate cross-talk between these two degradative pathways. It is still unclear whether autophagic vacuolization has a causative role in cell death or whether it represents the ultimate attempt of cells to cope with lethal stress. For a multicellular organism, autophagic cell death might well represent a pro-survival mechanism, by providing metabolic supplies during whole-body nutrient deprivation. Alternatively, type II cell death might contribute to the disposal of cell corpses when heterophagy is deficient. Here, we briefly review the roles of autophagy in cell death and its avoidance.


Assuntos
Autofagia/fisiologia , Morte Celular/fisiologia , Animais , Sobrevivência Celular , Humanos
13.
Cell ; 131(3): 476-91, 2007 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-17981116

RESUMO

Type-2 diabetes results from the development of insulin resistance and a concomitant impairment of insulin secretion. Recent studies place altered mitochondrial oxidative phosphorylation (OxPhos) as an underlying genetic element of insulin resistance. However, the causative or compensatory nature of these OxPhos changes has yet to be proven. Here, we show that muscle- and liver-specific AIF ablation in mice initiates a pattern of OxPhos deficiency closely mimicking that of human insulin resistance, and contrary to current expectations, results in increased glucose tolerance, reduced fat mass, and increased insulin sensitivity. These results are maintained upon high-fat feeding and in both genetic mosaic and ubiquitous OxPhos-deficient mutants. Importantly, the effects of AIF on glucose metabolism are acutely inducible and reversible. These findings establish that tissue-specific as well as global OxPhos defects in mice can counteract the development of insulin resistance, diabetes, and obesity.


Assuntos
Fator de Indução de Apoptose/deficiência , Diabetes Mellitus/prevenção & controle , Deleção de Genes , Marcação de Genes , Mitocôndrias/metabolismo , Obesidade/prevenção & controle , Fosforilação Oxidativa , Animais , Fator de Indução de Apoptose/genética , Respiração Celular/efeitos dos fármacos , Diabetes Mellitus/genética , Diabetes Mellitus/metabolismo , Dieta/efeitos adversos , Glucose/metabolismo , Insulina/farmacologia , Fígado/citologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Camundongos , Camundongos Knockout , Mitocôndrias/efeitos dos fármacos , Mosaicismo/efeitos dos fármacos , Músculos/citologia , Músculos/efeitos dos fármacos , Músculos/metabolismo , Obesidade/genética , Obesidade/metabolismo , Especificidade de Órgãos/efeitos dos fármacos , Fosforilação Oxidativa/efeitos dos fármacos , Fenótipo , Especificidade por Substrato/efeitos dos fármacos
14.
Proc Natl Acad Sci U S A ; 103(26): 9918-23, 2006 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-16788063

RESUMO

Apoptosis-inducing factor (AIF) is an evolutionarily conserved, ubiquitously expressed flavoprotein with NADH oxidase activity that is normally confined to mitochondria. In mammalian cells, AIF is released from mitochondria in response to apoptotic stimuli and translocates to the nucleus where it is thought to bind DNA and contribute to chromatinolysis and cell death in a caspase-independent manner. Here we describe the consequences of inactivating Aif in the early mouse embryo. Unexpectedly, we found that both the apoptosis-dependent process of cavitation in embryoid bodies and apoptosis associated with embryonic neural tube closure occur in the absence of AIF, indicating that Aif function is not required for apoptotic cell death in early mouse embryos. By embryonic day 9 (E9), loss of Aif function causes abnormal cell death, presumably because of reduced mitochondrial respiratory chain complex I activity. Because of this cell death, Aif null embryos fail to increase significantly in size after E9. Remarkably, patterning processes continue on an essentially normal schedule, such that E10 Aif null embryos with only approximately 1/10 the normal number of cells have the same somite number as their wild-type littermates. These observations show that pattern formation in the mouse can occur independent of embryo size and cell number.


Assuntos
Fator de Indução de Apoptose/fisiologia , Padronização Corporal , Complexo I de Transporte de Elétrons/metabolismo , Desenvolvimento Embrionário , Genes Letais , Animais , Fator de Indução de Apoptose/genética , Padronização Corporal/genética , Contagem de Células , Embrião de Mamíferos/enzimologia , Embrião de Mamíferos/ultraestrutura , Desenvolvimento Embrionário/genética , Feminino , Camundongos , Camundongos Endogâmicos , Mitocôndrias/enzimologia , Mutação
15.
EMBO J ; 25(17): 4061-73, 2006 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-16917506

RESUMO

The mitochondrial protein apoptosis-inducing factor (AIF) translocates to the nucleus and induces apoptosis. Recent studies, however, have indicated the importance of AIF for survival in mitochondria. In the absence of a means to dissociate these two functions, the precise roles of AIF remain unclear. Here, we dissociate these dual roles using mitochondrially anchored AIF that cannot be released during apoptosis. Forebrain-specific AIF null (tel. AifDelta) mice have defective cortical development and reduced neuronal survival due to defects in mitochondrial respiration. Mitochondria in AIF deficient neurons are fragmented with aberrant cristae, indicating a novel role of AIF in controlling mitochondrial structure. While tel. AifDelta Apaf1(-/-) neurons remain sensitive to DNA damage, mitochondrially anchored AIF expression in these cells significantly enhanced survival. AIF mutants that cannot translocate into nucleus failed to induce cell death. These results indicate that the proapoptotic role of AIF can be uncoupled from its physiological function. Cell death induced by AIF is through its proapoptotic activity once it is translocated to the nucleus, not due to the loss of AIF from the mitochondria.


Assuntos
Fator de Indução de Apoptose/fisiologia , Apoptose , Mitocôndrias/fisiologia , Trifosfato de Adenosina/metabolismo , Animais , Fator de Indução de Apoptose/genética , Sobrevivência Celular , Células Cultivadas , Dano ao DNA , Potenciais da Membrana/fisiologia , Camundongos , Camundongos Knockout , Microscopia Eletrônica de Transmissão , Mitocôndrias/ultraestrutura , Membranas Mitocondriais/metabolismo , Membranas Mitocondriais/ultraestrutura , Neurônios/fisiologia , Neurônios/ultraestrutura , Consumo de Oxigênio , Prosencéfalo/embriologia , Prosencéfalo/metabolismo , Transporte Proteico
16.
EMBO J ; 23(23): 4679-89, 2004 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-15526035

RESUMO

Apoptosis-inducing factor (AIF) is a mitochondrial flavoprotein that, after apoptosis induction, translocates to the nucleus where it participates in apoptotic chromatinolysis. Here, we show that human or mouse cells lacking AIF as a result of homologous recombination or small interfering RNA exhibit high lactate production and enhanced dependency on glycolytic ATP generation, due to severe reduction of respiratory chain complex I activity. Although AIF itself is not a part of complex I, AIF-deficient cells exhibit a reduced content of complex I and of its components, pointing to a role of AIF in the biogenesis and/or maintenance of this polyprotein complex. Harlequin mice with reduced AIF expression due to a retroviral insertion into the AIF gene also manifest a reduced oxidative phosphorylation (OXPHOS) in the retina and in the brain, correlating with reduced expression of complex I subunits, retinal degeneration, and neuronal defects. Altogether, these data point to a role of AIF in OXPHOS and emphasize the dual role of AIF in life and death.


Assuntos
Proteínas de Membrana/deficiência , Trifosfato de Adenosina/biossíntese , Animais , Apoptose , Fator de Indução de Apoptose , Encéfalo/metabolismo , Células Cultivadas , Complexo I de Transporte de Elétrons/biossíntese , Complexo III da Cadeia de Transporte de Elétrons/biossíntese , Flavoproteínas/genética , Flavoproteínas/metabolismo , Glucose/metabolismo , Humanos , Ácido Láctico/biossíntese , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Transgênicos , Mitocôndrias/metabolismo , Miocárdio/metabolismo , Especificidade de Órgãos , Fosforilação Oxidativa , Filogenia , RNA Interferente Pequeno/metabolismo , Retina/metabolismo , Leveduras/genética , Leveduras/crescimento & desenvolvimento , Leveduras/metabolismo
17.
Cell ; 108(1): 31-43, 2002 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-11792319

RESUMO

Control and treatment of chronic pain remain major clinical challenges. Progress may be facilitated by a greater understanding of the mechanisms underlying pain processing. Here we show that the calcium-sensing protein DREAM is a transcriptional repressor involved in modulating pain. dream(-/-) mice displayed markedly reduced responses in models of acute thermal, mechanical, and visceral pain. dream(-/-) mice also exhibited reduced pain behaviors in models of chronic neuropathic and inflammatory pain. However, dream(-/-) mice showed no major defects in motor function or learning and memory. Mice lacking DREAM had elevated levels of prodynorphin mRNA and dynorphin A peptides in the spinal cord, and the reduction of pain behaviors in dream(-/-) mice was mediated through dynorphin-selective kappa (kappa)-opiate receptors. Thus, DREAM appears to be a critical transcriptional repressor in pain processing.


Assuntos
Proteínas de Ligação ao Cálcio , Neuralgia/fisiopatologia , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Transcrição Gênica/fisiologia , Animais , Sequência de Bases , Comportamento Animal/fisiologia , Células Cultivadas , Sequência Consenso , Regulação para Baixo/fisiologia , Encefalinas/genética , Encefalinas/metabolismo , Coração/fisiologia , Hiperalgesia/fisiopatologia , Inflamação/fisiopatologia , Proteínas Interatuantes com Canais de Kv , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neuralgia/imunologia , Neurônios/citologia , Neurônios/fisiologia , Estimulação Física , Presenilina-1 , Presenilina-2 , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo , Proteínas Proto-Oncogênicas c-fos/genética , Proteínas Proto-Oncogênicas c-fos/metabolismo , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores Opioides kappa/metabolismo , Medula Espinal/citologia , Estimulação Química
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