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1.
Food Chem ; 304: 125428, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31476548

RESUMO

To protect allergic patients and guarantee correct food labeling, robust, specific and sensitive detection methods are urgently needed. Mass spectrometry (MS)-based methods could overcome the limitations of current detection techniques. The first step in the development of an MS-based method is the identification of biomarkers, which are, in the case of food allergens, peptides. Here, we implemented a strategy to identify the most salient peptide biomarkers in peanuts. Processed peanut matrices were prepared and analyzed using an untargeted approach via high-resolution MS. More than 300 identified peptides were further filtered using selection criteria to strengthen the analytical performance of a future, routine quantitative method. The resulting 16 peptides are robust to food processing, specific to peanuts, and satisfy sequence-based criteria. The aspect of multiple protein isoforms is also considered in the selection tree, an aspect that is essential for a quantitative method's robustness but seldom, if ever, considered.

2.
Food Chem ; : 125679, 2019 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-31718834

RESUMO

The interest of using LC-MS/MS as a method for detection of allergens in food is growing. In such methods, peptides are used as biomarkers for the detection and quantification of the allergens. The selection of good biomarker peptides is of high importance to develop a specific, universal and sensitive method. Biomarkers should, for example, be robust to food processing. To evaluate robustness, test material incurred with hazelnut having undergone different food processing techniques was produced. Proteins of these materials were extracted, digested and further analyzed using HRMS. After peptide identification, selection was carried out using several criteria such as hazelnut specificity and amino acid composition. Further selection was done by comparing peptide MS intensities in the different food matrices. Only peptides showing processing robustness were retained. Eventually, eight peptides coming from three major hazelnut proteins were selected as the best biomarkers for hazelnut detection in processed foods.

3.
Biochem Pharmacol ; 169: 113621, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31472127

RESUMO

Cell differentiation is a fundamental biological event in which a precursor stem cell is turning into a specialized somatic cell. It is thus crucial for the development, tissue turnover and regeneration in mammals. Among the numerous changes taking place in a cell during a differentiation programme, the biology of mitochondria, the central organelle mainly responsible for energy homeostasis and stress adaptation, is deeply modified. These modifications are now well recognized as taking an active part to the completion of the differentiation programme. Indeed, mitochondrial biogenesis and metabolic shift are observed during cell differentiation, adapting many syntheses, calcium homeostasis, ATP and reactive oxygen species production, to the needs. These mitochondrial functions are substantially regulated by the post-translational modifications of the mitochondrial proteins among which lysine acetylation is essential. This mitoacetylome is then globally controlled by the balance between spontaneous/enzymatically-catalysed protein acetylation and the NAD+-dependent deacetylation mediated by Sirtuin 3. This enzyme is now considered as a major regulator of the function of the organelle. Regarding the requirement of these mitochondrial adaptations, the subsequent growing interest for this enzyme recently extended to the investigation of the mechanisms driving cell differentiation. This review summarizes the currently available information about the significance of SIRT3 in cell differentiation in physio-pathological contexts. We also suggest a control of the differentiation-activated autophagy by SIRT3, a hypothesis supported by recent findings establishing a causal link between SIRT3 and autophagy. Eventually, an update on the present pharmacological modulators of SIRT3 in a context of cell differentiation is discussed.

4.
Cells ; 8(8)2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31366145

RESUMO

Mitochondrial uncoupling can be defined as a dissociation between mitochondrial membrane potential generation and its use for mitochondria-dependent ATP synthesis. Although this process was originally considered a mitochondrial dysfunction, the identification of UCP-1 as an endogenous physiological uncoupling protein suggests that the process could be involved in many other biological processes. In this review, we first compare the mitochondrial uncoupling agents available in term of mechanistic and non-specific effects. Proteins regulating mitochondrial uncoupling, as well as chemical compounds with uncoupling properties are discussed. Second, we summarize the most recent findings linking mitochondrial uncoupling and other cellular or biological processes, such as bulk and specific autophagy, reactive oxygen species production, protein secretion, cell death, physical exercise, metabolic adaptations in adipose tissue, and cell signaling. Finally, we show how mitochondrial uncoupling could be used to treat several human diseases, such as obesity, cardiovascular diseases, or neurological disorders.

5.
Artigo em Inglês | MEDLINE | ID: mdl-30360050

RESUMO

The number of patients suffering from diseases linked with hormone deficiency (e.g. type 1 diabetes mellitus) has significantly increased in recent years. As organ transplantation presents its limits, the design of novel robust devices for cell encapsulation is of great interest. The current study reports the design of a novel hybrid alginate microcapsule reinforced by titania via a biocompatible synthesis from an aqueous stable titania precursor (TiBALDH) and a cationic polyamine (PDDAC) under mild conditions. The biocompatibility of this one-pot synthesis was confirmed by evaluation of the cytotoxicity of the precursor, additive, product and by-product. The morphology, structure and properties of the obtained hybrid microcapsule were characterized in detail. The microcapsule displayed mesoporous, which was a key parameter to allow the diffusion of nutrients and metabolites and to avoid the entry of immune defenders. The hybrid microcapsule also showed enhanced mechanical stability compared to the pure alginate microcapsule, making it an ideal candidate as a cell reservoir. HepG2 model cells encapsulated in the hybrid microcapsules remained intact for 43 days as highlighted by fluorescent viability probes, their oxygen consumption, and their albumin secretion. The study provides a significant progress in the conception of the robust and biocompatible reservoirs of animal cells for cell therapy.

6.
PLoS One ; 13(5): e0197603, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29772029

RESUMO

BACKGROUND: Prolyl carboxypeptidase (PRCP) is involved in the regulation of body weight, likely by hydrolysing alpha-melanocyte-stimulating hormone and apelin in the hypothalamus and in the periphery. A link between PRCP protein concentrations in plasma and metabolic disorders has been reported. In this study, we investigated the distribution of circulating PRCP activity and assessed its relation with body weight and adipose tissue in obese patients and patients who significantly lost weight. METHODS: PRCP activity was measured using reversed-phase high-performance liquid chromatography in different isolated blood fractions and primary human cells to investigate the distribution of circulating PRCP. PRCP activity was measured in serum of individuals (n = 75) categorized based on their body mass index (BMI < 25.0; 25.0-29.9; 30.0-39.9; ≥ 40.0 kg/m2) and the diagnosis of metabolic syndrome. Differences in serum PRCP activity were determined before and six months after weight loss, either by diet (n = 45) or by bariatric surgery (n = 24). Potential correlations between serum PRCP activity and several metabolic and biochemical parameters were assessed. Additionally, plasma PRCP concentrations were quantified using a sensitive ELISA in the bariatric surgery group. RESULTS: White blood cells and plasma contributed the most to circulating PRCP activity. Serum PRCP activity in lean subjects was 0.83 ± 0.04 U/L and increased significantly with a rising BMI (p<0.001) and decreased upon weight loss (diet, p<0.05; bariatric surgery, p<0.001). The serum PRCP activity alteration reflected body weight changes and was found to be positively correlated with several metabolic parameters, including: total, abdominal and visceral adipose tissue. Plasma PRCP concentration was found to be significantly correlated to serum PRCP activity (0.865; p<0.001). Additionally, a significant decrease (p<0.001) in plasma PRCP protein concentration (mean ± SD) before (18.2 ± 3.7 ng/mL) and 6 months after bariatric surgery (15.7 ± 2.7 ng/mL) was found. CONCLUSION: Our novel findings demonstrate that white blood cells and plasma contributed the most to circulating PRCP activity. Additionally, we have shown that there were significant correlations between serum PRCP activity and various metabolic parameters, and that plasma PRCP concentration was significantly correlated to serum PRCP activity. These novel findings on PRCP activity in serum support further investigation of its in vivo role and involvement in several metabolic diseases.

7.
Sci Rep ; 8(1): 5173, 2018 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-29581535

RESUMO

Mitochondria are complex organelles that participate in many cellular functions, ranging from ATP production to immune responses against viruses and bacteria. This integration of a plethora of functions within a single organelle makes mitochondria a very attractive target to manipulate for intracellular pathogens. We characterised the crosstalk that exists between Brucella abortus, the causative agent of brucellosis, and the mitochondria of infected cells. Brucella replicates in a compartment derived from the endoplasmic reticulum (ER) and modulates ER functionality by activating the unfolded protein response. However, the impact of Brucella on the mitochondrial population of infected cells still requires a systematic study. We observed physical contacts between Brucella containing vacuoles and mitochondria. We also found that B. abortus replication is independent of mitochondrial oxidative phosphorylation and that mitochondrial reactive oxygen species do not participate to the control of B. abortus infection in vitro. We demonstrated that B. abortus and B. melitensis induce a drastic mitochondrial fragmentation at 48 hours post-infection in different cell types, including myeloid and non-myeloid cells. This fragmentation is DRP1-independent and might be caused by a deficit of mitochondrial fusion. However, mitochondrial fragmentation does not change neither Brucella replication efficiency, nor the susceptibility of infected cells to TNFα-induced apoptosis.

8.
J Cell Physiol ; 233(2): 1247-1265, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28488768

RESUMO

Obesity is characterized by an excessive triacylglycerol accumulation in white adipocytes. Various mechanisms allowing the tight regulation of triacylglycerol storage and mobilization by lipid droplet-associated proteins as well as lipolytic enzymes have been identified. Increasing energy expenditure by inducing a mild uncoupling of mitochondria in adipocytes might represent a putative interesting anti-obesity strategy as it reduces the adipose tissue triacylglycerol content (limiting alterations caused by cell hypertrophy) by stimulating lipolysis through yet unknown mechanisms, limiting the adverse effects of adipocyte hypertrophy. Herein, the molecular mechanisms involved in lipolysis induced by a mild uncoupling of mitochondria in white 3T3-L1 adipocytes were characterized. Mitochondrial uncoupling-induced lipolysis was found to be independent from canonical pathways that involve lipolytic enzymes such as HSL and ATGL. Finally, enhanced lipolysis in response to mitochondrial uncoupling relies on a form of autophagy as lipid droplets are captured by endolysosomal vesicles. This new mechanism of triacylglycerol breakdown in adipocytes exposed to mild uncoupling provides new insights on the biology of adipocytes dealing with mitochondria forced to dissipate energy.


Assuntos
Adipócitos/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Carbonil Cianeto p-Trifluormetoxifenil Hidrazona/farmacologia , Lipase/metabolismo , Lipólise/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Esterol Esterase/metabolismo , Triglicerídeos/metabolismo , Desacopladores/farmacologia , Células 3T3-L1 , Adipócitos/metabolismo , Adipócitos/ultraestrutura , Animais , Proteína 5 Relacionada à Autofagia/genética , Proteína 5 Relacionada à Autofagia/metabolismo , Proteína 7 Relacionada à Autofagia/genética , Proteína 7 Relacionada à Autofagia/metabolismo , Gotículas Lipídicas/metabolismo , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Macrolídeos/farmacologia , Camundongos , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Interferência de RNA , Transfecção
9.
Stem Cells ; 35(10): 2184-2197, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28795454

RESUMO

Increasing evidence supports that modifications in the mitochondrial content, oxidative phosphorylation (OXPHOS) activity, and cell metabolism influence the fate of stem cells. However, the regulators involved in the crosstalk between mitochondria and stem cell fate remains poorly characterized. Here, we identified a transcriptional regulatory axis, composed of transcription factor 7-like 2 (TCF7L2) (a downstream effector of the Wnt/ß-catenin pathway, repressed during differentiation) and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) (the master regulator of mitochondrial biogenesis, induced during differentiation), coupling the loss of pluripotency and early commitment to differentiation, to the initiation of mitochondrial biogenesis and metabolic shift toward OXPHOS. PGC-1α induction during differentiation is required for both mitochondrial biogenesis and commitment to the hepatocytic lineage, and TCF7L2 repression is sufficient to increase PGC-1α expression, mitochondrial biogenesis and OXPHOS activity. We further demonstrate that OXPHOS activity is required for the differentiation toward the hepatocytic lineage, thus providing evidence that bi-directional interactions control stem cell differentiation and mitochondrial abundance and activity. Stem Cells 2017;35:2184-2197.


Assuntos
Fígado/citologia , Fígado/metabolismo , Mitocôndrias Hepáticas/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Proteína 2 Semelhante ao Fator 7 de Transcrição/metabolismo , Diferenciação Celular/fisiologia , Células Cultivadas , Hepatócitos/citologia , Hepatócitos/metabolismo , Humanos , Fígado/crescimento & desenvolvimento , Biogênese de Organelas , Fosforilação Oxidativa , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/biossíntese , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Transdução de Sinais , Proteína 2 Semelhante ao Fator 7 de Transcrição/genética , Transfecção , beta Catenina/metabolismo
10.
J AOAC Int ; 100(4): 1126-1130, 2017 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-28330529

RESUMO

Food laboratories have developed methods for testing allergens in foods. The efficiency of qualitative and quantitative methods is of prime importance in protecting allergic populations. Unfortunately, food laboratories encounter barriers to developing efficient methods. Bottlenecks include the lack of regulatory thresholds, delays in the emergence of reference materials and guidelines, and the need to detect processed allergens. In this study, ultra-HPLC coupled to tandem MS was used to illustrate difficulties encountered in determining method performances. We measured the major influences of both processing and matrix effects on the detection of egg, milk, soy, and peanut allergens in foodstuffs. The main goals of this work were to identify difficulties that food laboratories still encounter in detecting and quantifying allergens and to sensitize researchers to them.


Assuntos
Alérgenos/análise , Análise de Alimentos/métodos , Espectrometria de Massas em Tandem , Animais , Cromatografia Líquida de Alta Pressão , Hipersensibilidade Alimentar , Humanos
11.
J Cell Physiol ; 231(9): 1913-31, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26680008

RESUMO

Endoplasmic reticulum (ER) and mitochondria are not discrete intracellular organelles but establish close physical and functional interactions involved in several biological processes including mitochondrial bioenergetics, calcium homeostasis, lipid synthesis, and the regulation of apoptotic cell death pathways. As many cell types might face a transient and sublethal ER stress during their lifetime, it is thus likely that the adaptive UPR response might affect the mitochondrial population. The aim of this work was to study the putative effects of a non-lethal and transient endoplasmic reticulum stress on the mitochondrial population in HepG2 cells. The results show that thapsigargin and brefeldin A, used to induce a transient and sublethal ER stress, rapidly lead to the fragmentation of the mitochondrial network associated with a decrease in mitochondrial membrane potential, O2 (•-) production and less efficient respiration. These changes in mitochondrial function are transient and preceded by the phosphorylation of JNK. Inhibition of JNK activation by SP600125 prevents the decrease in O2 (•-) production and the mitochondrial network fragmentation observed in cells exposed to the ER stress but has no impact on the reduction of the mitochondrial membrane potential. In conclusion, our data show that a non-lethal and transient ER stress triggers a rapid activation of JNK without inducing apoptosis, leading to the fragmentation of the mitochondrial network and a reduction of O2 (•-) production. J. Cell. Physiol. 231: 1913-1931, 2016. © 2015 Wiley Periodicals, Inc.


Assuntos
Apoptose/efeitos dos fármacos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/efeitos dos fármacos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Tapsigargina/farmacologia , Retículo Endoplasmático/metabolismo , Metabolismo Energético/efeitos dos fármacos , Células Hep G2 , Humanos , Mitocôndrias/metabolismo
12.
Int J Mol Sci ; 16(8): 18224-51, 2015 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-26258774

RESUMO

Mitochondrial unfolded protein response is a form of retrograde signaling that contributes to ensuring the maintenance of quality control of mitochondria, allowing functional integrity of the mitochondrial proteome. When misfolded proteins or unassembled complexes accumulate beyond the folding capacity, it leads to alteration of proteostasis, damages, and organelle/cell dysfunction. Extensively studied for the ER, it was recently reported that this kind of signaling for mitochondrion would also be able to communicate with the nucleus in response to impaired proteostasis. The mitochondrial unfolded protein response (UPR(mt)) is activated in response to different types and levels of stress, especially in conditions where unfolded or misfolded mitochondrial proteins accumulate and aggregate. A specific UPR(mt) could thus be initiated to boost folding and degradation capacity in response to unfolded and aggregated protein accumulation. Although first described in mammals, the UPR(mt) was mainly studied in Caenorhabditis elegans, and accumulating evidence suggests that mechanisms triggered in response to a UPR(mt) might be different in C. elegans and mammals. In this review, we discuss and integrate recent data from the literature to address whether the UPR(mt) is relevant to mitochondrial homeostasis in mammals and to analyze the putative role of integrated stress response (ISR) activation in response to the inhibition of mtDNA expression and/or accumulation of mitochondrial mis/unfolded proteins.


Assuntos
DNA Mitocondrial/genética , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Resposta a Proteínas não Dobradas , Animais , DNA Mitocondrial/metabolismo , Regulação da Expressão Gênica , Homeostase , Humanos , Mitocôndrias/genética , Proteínas Mitocondriais/genética , Transdução de Sinais , Estresse Fisiológico
13.
Stem Cells Dev ; 24(17): 1957-71, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-26134242

RESUMO

As sites of cellular respiration and energy production, mitochondria play a central role in cell metabolism. Cell differentiation is associated with an increase in mitochondrial content and activity and with a metabolic shift toward increased oxidative phosphorylation activity. The opposite occurs during reprogramming of somatic cells into induced pluripotent stem cells. Studies have provided evidence of mitochondrial and metabolic changes during the differentiation of both embryonic and somatic (or adult) stem cells (SSCs), such as hematopoietic stem cells, mesenchymal stem cells, and tissue-specific progenitor cells. We thus propose to consider those mitochondrial and metabolic changes as hallmarks of differentiation processes. We review how mitochondrial biogenesis, dynamics, and function are directly involved in embryonic and SSC differentiation and how metabolic and sensing pathways connect mitochondria and metabolism with cell fate and pluripotency. Understanding the basis of the crosstalk between mitochondria and cell fate is of critical importance, given the promising application of stem cells in regenerative medicine. In addition to the development of novel strategies to improve the in vitro lineage-directed differentiation of stem cells, understanding the molecular basis of this interplay could lead to the identification of novel targets to improve the treatment of degenerative diseases.


Assuntos
Células-Tronco Adultas/citologia , Diferenciação Celular/fisiologia , Metabolismo Energético/fisiologia , Mitocôndrias/metabolismo , Células-Tronco Pluripotentes/citologia , Animais , Proliferação de Células/fisiologia , Humanos
14.
Mol Cancer ; 14: 79, 2015 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-25889892

RESUMO

BACKGROUND: Tumor hypoxia is one of the features of tumor microenvironment that contributes to chemoresistance. miRNAs have recently been shown to play important roles in tumorigenesis and drug resistance. Moreover, hypoxia also regulates the expression of a series of miRNAs. However, the interaction between chemoresistance, hypoxia and miRNAs has not been explored yet. The aim of this study is to understand the mechanisms activated/inhibited by miRNAs under hypoxia that induce resistance to chemotherapy-induced apoptosis. METHODS: TaqMan low-density array was used to identify changes in miRNA expression when cells were exposed to etoposide under hypoxia or normoxia. The effects of miR-196b overexpression on apoptosis and cell proliferation were studied in HepG2 cells. miR-196b target mRNAs were identified by proteomic analysis, luciferase activity assay, RT-qPCR and western blot analysis. RESULTS: Results showed that hypoxia down-regulated miR-196b expression that was induced by etoposide. miR-196b overexpression increased the etoposide-induced apoptosis and reversed the protection of cell death observed under hypoxia. By a proteomic approach combined with bioinformatics analyses, we identified IGF2BP1 as a potential target of miR-196b. Indeed, miR-196b overexpression decreased IGF2BP1 RNA expression and protein level. The IGF2BP1 down-regulation by either miR-196b or IGF2BP1 siRNA led to an increase in apoptosis and a decrease in cell viability and proliferation in normal culture conditions. However, IGF2BP1 silencing did not modify the chemoresistance induced by hypoxia, probably because it is not the only target of miR-196b involved in the regulation of apoptosis. CONCLUSIONS: In conclusion, for the first time, we identified IGF2BP1 as a direct and functional target of miR-196b and showed that miR-196b overexpression reverses the chemoresistance induced by hypoxia. These results emphasize that the chemoresistance induced by hypoxia is a complex mechanism.


Assuntos
Apoptose/genética , Proliferação de Células/genética , MicroRNAs/genética , Proteínas de Ligação a RNA/genética , Apoptose/efeitos dos fármacos , Hipóxia Celular/efeitos dos fármacos , Hipóxia Celular/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/genética , Resistencia a Medicamentos Antineoplásicos/genética , Etoposídeo/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/genética , Células Hep G2 , Humanos , Proteômica/métodos
15.
Oncotarget ; 6(13): 11264-80, 2015 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-25834103

RESUMO

Lipogenesis inhibition was reported to induce apoptosis and repress proliferation of cancer cells while barely affecting normal cells. Lipins exhibit dual function as enzymes catalyzing the dephosphorylation of phosphatidic acid to diacylglycerol and as co-transcriptional regulators. Thus, they are able to regulate lipid homeostasis at several nodal points. Here, we show that lipin-1 is up-regulated in several cancer cell lines and overexpressed in 50 % of high grade prostate cancers. The proliferation of prostate and breast cancer cells, but not of non-tumorigenic cells, was repressed upon lipin-1 knock-down. Lipin-1 depletion also decreased cancer cell migration through RhoA activation. Lipin-1 silencing did not significantly affect global lipid synthesis but enhanced the cellular concentration of phosphatidic acid. In parallel, autophagy was induced while AKT and ribosomal protein S6 phosphorylation were repressed. We also observed a compensatory regulation between lipin-1 and lipin-2 and demonstrated that their co-silencing aggravates the phenotype induced by lipin-1 silencing alone. Most interestingly, lipin-1 depletion or lipins inhibition with propranolol sensitized cancer cells to rapamycin. These data indicate that lipin-1 controls main cellular processes involved in cancer progression and that its targeting, alone or in combination with other treatments, could open new avenues in anticancer therapy.


Assuntos
Antibióticos Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Lipogênese , Fosfatidato Fosfatase/metabolismo , Neoplasias da Próstata/tratamento farmacológico , Sirolimo/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Neoplasias da Mama/enzimologia , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Terapia de Alvo Molecular , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Fosfatidato Fosfatase/antagonistas & inibidores , Fosfatidato Fosfatase/genética , Fosforilação , Propranolol/farmacologia , Neoplasias da Próstata/enzimologia , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Interferência de RNA , Proteína S6 Ribossômica/metabolismo , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/metabolismo , Fatores de Tempo , Transfecção , Proteína rhoA de Ligação ao GTP/genética , Proteína rhoA de Ligação ao GTP/metabolismo
16.
PLoS One ; 10(3): e0115831, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25794149

RESUMO

Cancer is still one of the leading causes of death worldwide, and finding new treatments remains a major challenge. Previous studies showed that modified forms of pectin, a complex polysaccharide present in the primary plant cell wall, possess anticancer properties. Nevertheless, the mechanism of action of modified pectin and the pathways involved are unclear. Here, we show that citrus pectin modified by heat treatment induced cell death in HepG2 and A549 cells. The induced cell death differs from classical apoptosis because no DNA cleavage was observed. In addition, Z-VAD-fmk, a pan-caspase inhibitor, did not influence the observed cell death in HepG2 cells but appeared to be partly protective in A549 cells, indicating that heat-modified citrus pectin might induce caspase-independent cell death. An increase in the abundance of the phosphatidylethanolamine-conjugated Light Chain 3 (LC3) protein and a decrease in p62 protein abundance were observed in both cell types when incubated in the presence of heat-modified citrus pectin. These results indicate the activation of autophagy. To our knowledge, this is the first time that autophagy has been revealed in cells incubated in the presence of a modified form of pectin. This autophagy activation appears to be protective, at least for A549 cells, because its inhibition with 3-methyladenine increased the observed modified pectin-induced cytotoxicity. This study confirms the potential of modified pectin to improve chemotherapeutic cancer treatments.


Assuntos
Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Temperatura Alta , Pectinas/farmacologia , Adenina/análogos & derivados , Adenina/farmacologia , Proteínas de Transporte/metabolismo , Inibidores de Caspase/farmacologia , Caspases/metabolismo , Linhagem Celular Tumoral , Células Hep G2 , Humanos , Macrolídeos/farmacologia , Proteínas dos Microfilamentos/metabolismo , Ubiquitinação/efeitos dos fármacos
17.
Int J Biochem Cell Biol ; 62: 1-14, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25724736

RESUMO

Understanding the mechanisms responsible for the resistance against chemotherapy-induced cell death is still of great interest since the number of patients with cancer increases and relapse is commonly observed. Indeed, the development of hypoxic regions as well as UPR (unfolded protein response) activation is known to promote cancer cell adaptive responses to the stressful tumor microenvironment and resistance against anticancer therapies. Therefore, the impact of UPR combined to hypoxia on autophagy and apoptosis activation during taxol exposure was investigated in MDA-MB-231 and T47D breast cancer cells. The results showed that taxol rapidly induced UPR activation and that hypoxia modulated taxol-induced UPR activation differently according to the different UPR pathways (PERK, ATF6, and IRE1α). The putative involvement of these signaling pathways in autophagy or in apoptosis regulation in response to taxol exposure was investigated. However, while no link between the activation of these three ER stress sensors and autophagy or apoptosis regulation could be evidenced, results showed that ATF4 activation, which occurs independently of UPR activation, was involved in taxol-induced autophagy completion. In addition, an ATF4-dependent mechanism leading to cancer cell adaptation and resistance against taxol-induced cell death was evidenced. Finally, our results demonstrate that expression of ATF4, in association with hypoxia-induced genes, can be used as a biomarker of a poor prognosis for human breast cancer patients supporting the conclusion that ATF4 might play an important role in adaptation and resistance of breast cancer cells to chemotherapy in hypoxic tumors.


Assuntos
Fator 4 Ativador da Transcrição/genética , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Paclitaxel/farmacologia , Resposta a Proteínas não Dobradas/efeitos dos fármacos , Fator 4 Ativador da Transcrição/metabolismo , Apoptose/genética , Autofagia/genética , Neoplasias da Mama/patologia , Hipóxia Celular/efeitos dos fármacos , Hipóxia Celular/genética , Regulação para Baixo/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Ativação Transcricional/efeitos dos fármacos , Células Tumorais Cultivadas
18.
Biochem Pharmacol ; 94(3): 173-85, 2015 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-25707982

RESUMO

Eukaryotic cells developed strategies to detect and eradicate infections. The innate immune system, which is the first line of defence against invading pathogens, relies on the recognition of molecular patterns conserved among pathogens. Pathogen associated molecular pattern binding to pattern recognition receptor triggers the activation of several signalling pathways leading to the establishment of a pro-inflammatory state required to control the infection. In addition, pathogens evolved to subvert those responses (with passive and active strategies) allowing their entry and persistence in the host cells and tissues. Indeed, several bacteria actively manipulate immune system or interfere with the cell fate for their own benefit. One can imagine that bacterial effectors can potentially manipulate every single organelle in the cell. However, the multiple functions fulfilled by mitochondria especially their involvement in the regulation of innate immune response, make mitochondria a target of choice for bacterial pathogens as they are not only a key component of the central metabolism through ATP production and synthesis of various biomolecules but they also take part to cell signalling through ROS production and control of calcium homeostasis as well as the control of cell survival/programmed cell death. Furthermore, considering that mitochondria derived from an ancestral bacterial endosymbiosis, it is not surprising that a special connection does exist between this organelle and bacteria. In this review, we will discuss different mitochondrial functions that are affected during bacterial infection as well as different strategies developed by bacterial pathogens to subvert functions related to calcium homeostasis, maintenance of redox status and mitochondrial morphology.


Assuntos
Fenômenos Fisiológicos Bacterianos , Mitocôndrias/microbiologia , Metabolismo Energético , Mitocôndrias/fisiologia , Transdução de Sinais
19.
Mitochondrion ; 21: 58-68, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25643991

RESUMO

Mitochondria-to-nucleus communication, known as retrograde signaling, is important to adjust the nuclear gene expression in response to organelle dysfunction. Among the transcription factors described to respond to mitochondrial stress, CHOP-10 is activated by respiratory chain inhibition, mitochondrial accumulation of unfolded proteins and mtDNA mutations. In this study, we show that altered/impaired expression of mtDNA induces CHOP-10 expression in a signaling pathway that depends on the eIF2α/ATF4 axis of the integrated stress response rather than on the mitochondrial unfolded protein response.


Assuntos
Expressão Gênica , Genoma Mitocondrial , Transdução de Sinais , Estresse Fisiológico , Fator de Transcrição CHOP/metabolismo , Fator 4 Ativador da Transcrição/metabolismo , Linhagem Celular , Fator de Iniciação 2 em Eucariotos/metabolismo , Humanos , Resposta a Proteínas não Dobradas
20.
Metabolites ; 4(3): 831-78, 2014 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-25257998

RESUMO

Mitochondrial dysfunction(s) (MDs) can be defined as alterations in the mitochondria, including mitochondrial uncoupling, mitochondrial depolarization, inhibition of the mitochondrial respiratory chain, mitochondrial network fragmentation, mitochondrial or nuclear DNA mutations and the mitochondrial accumulation of protein aggregates. All these MDs are known to alter the capacity of ATP production and are observed in several pathological states/diseases, including cancer, obesity, muscle and neurological disorders. The induction of MDs can also alter the secretion of several metabolites, reactive oxygen species production and modify several cell-signalling pathways to resolve the mitochondrial dysfunction or ultimately trigger cell death. Many metabolites, such as fatty acids and derived compounds, could be secreted into the blood stream by cells suffering from mitochondrial alterations. In this review, we summarize how a mitochondrial uncoupling can modify metabolites, the signalling pathways and transcription factors involved in this process. We describe how to identify the causes or consequences of mitochondrial dysfunction using metabolomics (liquid and gas chromatography associated with mass spectrometry analysis, NMR spectroscopy) in the obesity and insulin resistance thematic.

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