RESUMO
We measure the thermal conductivity of solid and molten tungsten using steady state temperature differential radiometry. We demonstrate that the thermal conductivity can be well described by application of Wiedemann-Franz law to electrical resistivity data, thus suggesting the validity of Wiedemann-Franz law to capture the electronic thermal conductivity of metals in their molten phase. We further support this conclusion using ab initio molecular dynamics simulations with a machine-learned potential. Our results show that at these high temperatures, the vibrational contribution to thermal conductivity is negligible compared to the electronic component.
RESUMO
Paclitaxel is widely used in the treatment of patients with metastatic breast cancer (MBC). Formulations of paclitaxel contain surfactants and solvents or albumin derived from human blood. The use of co-solvents such as polyoxyethylated castor oil is thought to contribute to toxicity profile and hypersensitivity reactions as well as leaching of plasticizers from polyvinyl chloride bags and infusion sets. Currently, nab-paclitaxel, an albumin-bound paclitaxel in nanometer range continues to be the preferred taxane formulation used in clinic. This study (CTRI/2010/091/001116) investigated the efficacy and tolerability of a polyoxyethylated castor oil- and albumin-free formulation of paclitaxel [paclitaxel injection concentrate for nanodispersion (PICN)] compared with nab-paclitaxel in women with refractory MBC. The current study was a multicenter, open-label, parallel-group, randomized, comparative phase II/III trial evaluating the efficacy and safety of PICN (260 mg/m(2) [n = 64] and 295 mg/m(2) [n = 58] every 3 weeks) compared with nab-paclitaxel (260 mg/m(2) every 3 weeks [n = 58]) in women 18 and 70 years old with confirmed MBC. Overall response rate (ORR) was assessed with imaging every 2 cycles. An independent analysis of radiologic data was performed for evaluable patients. Progression-free survival (PFS) was a secondary efficacy measure. Independent radiologist-assessed ORRs in the evaluable population of women aged ≥70 years were 35, 49, and 43 % in the PICN 260 mg/m(2), PICN 295 mg/m(2), and nab-paclitaxel 260 mg/m(2) arms, respectively. Median PFS in the evaluable population was 23, 35, and 34 weeks in the PICN 260 mg/m(2), PICN 295 mg/m(2), and nab-paclitaxel 260 mg/m(2) arms, respectively. Adverse events occurred in similar proportions of patients across treatment arms. Hypersensitivity reactions were not frequently observed with the clinical use of PICN across the treatment cohorts. In women with metastatic breast cancer, PICN at 260 and 295 mg/m(2) every 3 weeks was effective and well tolerated and showed similar tolerability compared with nab-paclitaxel 260 mg/m(2) every 3 weeks. Statistically, significant differences were not observed in the PICN and nab-paclitaxel treatment arms for radiologist-assessed ORR or median PFS. The novel paclitaxel formulation, PICN, offers apart from efficacy, potential safety advantage of decreased use of corticosteroid pretreatment and the absence of the risk of transmission of blood product-borne disease.
Assuntos
Albuminas/administração & dosagem , Antineoplásicos/administração & dosagem , Neoplasias da Mama/tratamento farmacológico , Paclitaxel/administração & dosagem , Adulto , Idoso , Albuminas/uso terapêutico , Antineoplásicos/uso terapêutico , Feminino , Humanos , Injeções , Pessoa de Meia-Idade , Metástase Neoplásica , Paclitaxel/uso terapêutico , Análise de Sobrevida , Resultado do Tratamento , Adulto JovemRESUMO
Context Oxidative stress induces apoptosis within Islets of Langerhans in diabetes mellitus (DM). Enicostemma littorale blume, herb of the Gentianaceae family is used as an anti-diabetic agent across rural India. Objective This report demonstrates potent anti-apoptotic and cyto-protective activity of Enicostemma littorale MeOH extract (EL MeOH ext.) against 50 µM H2O2 in isolated rat Islets. Materials and methods In this study, the whole plant methanolic extract of EL with doses 0.25-4 mg/mL each for the preincubation duration of 0.5-4 h against 50 µM H2O2 were tested for optimum protective dose and time by Trypan blue dye exclusion assay. Islet intracellular reactive oxygen species (ROS) was quantified by DCFDA staining and cell death using PS/PI & FDA/PI staining. Further, comet assay, biochemical assessment of caspase-3 and antioxidant enzyme activities along with immunoblotting of PARP-1, caspase-3, TNF-α activation and p-P38 MapK (stress kinase) induction was performed. Results The optimized dose of EL MeOH ext. 2 mg/mL for 2 h was used throughout the study, which significantly decreased total Intracellular ROS and cell death. Further, caspase-3 activity, PARP-1 cleavage, p-P38 MapK (stress kinase) activation and TNF-α levels, which had been significantly elevated, were normalized. Antioxidant enzymes like catalase, superoxide dismutase, reduced glutathione and glutathione peroxidase, along with Comet assay, demonstrated that pretreatment with EL MeOH ext. can augment antioxidant enzyme activities and protect from DNA damage. Discussion and conclusions Significant anti-apoptotic and cyto-protective effects were mediated by EL with Islets of Langerhans subjected to oxidative stress-induced cell death.
Assuntos
Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Gentianaceae , Ilhotas Pancreáticas/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/farmacologia , Animais , Antioxidantes/isolamento & purificação , Proteínas Reguladoras de Apoptose/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Citoproteção , Dano ao DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Gentianaceae/química , Peróxido de Hidrogênio/toxicidade , Ilhotas Pancreáticas/enzimologia , Ilhotas Pancreáticas/patologia , Masculino , Metanol/química , Fitoterapia , Extratos Vegetais/isolamento & purificação , Plantas Medicinais , Ratos , Espécies Reativas de Oxigênio/metabolismo , Solventes/química , Fatores de Tempo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Hearts from type 2 diabetic (T2DM) subjects are chronically subjected to hyperglycemia and hyperlipidemia, both thought to contribute to oxidizing conditions and contractile dysfunction. How redox alterations and contractility interrelate, ultimately diminishing T2DM heart function, remains poorly understood. Herein we tested whether the fatty acid palmitate (Palm), in addition to its energetic contribution, rescues function by improving redox [glutathione (GSH), NAD(P)H, less oxidative stress] in T2DM rat heart trabeculae subjected to high glucose. Using cardiac trabeculae from Zucker Diabetic Fatty (ZDF) rats, we assessed the impact of low glucose (EG) and high glucose (HG), in absence or presence of Palm or insulin, on force development, energetics, and redox responses. We found that in EG ZDF and lean trabeculae displayed similar contractile work, yield of contractile work (Ycw), representing the ratio of force time integral over rate of O2 consumption. Conversely, HG had a negative impact on Ycw, whereas Palm, but not insulin, completely prevented contractile loss. This effect was associated with higher GSH, less oxidative stress, and augmented matrix GSH/thioredoxin (Trx) in ZDF mitochondria. Restoration of myocardial redox with GSH ethyl ester also rescued ZDF contractile function in HG, independently from Palm. These results support the idea that maintained redox balance, via increased GSH and Trx antioxidant activities to resist oxidative stress, is an essential protective response of the diabetic heart to keep contractile function.
Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Cardiomiopatias Diabéticas/metabolismo , Contração Miocárdica , Miocárdio/metabolismo , Estresse Oxidativo , Animais , Diabetes Mellitus Tipo 2/fisiopatologia , Cardiomiopatias Diabéticas/fisiopatologia , Glutationa/metabolismo , Coração/efeitos dos fármacos , Coração/fisiopatologia , Insulina/sangue , Mitocôndrias Cardíacas/efeitos dos fármacos , Mitocôndrias Cardíacas/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Oxirredução , Consumo de Oxigênio , Palmitatos/sangue , Palmitatos/farmacologia , Ratos , Ratos Zucker , Tiorredoxinas/metabolismoRESUMO
The effect of inhalational anesthetics on myocardial contraction and energetics in type 2 diabetes mellitus is unknown. We investigated the effect of isoflurane (ISO) on force and intracellular Ca(2+) transient (iCa), myocardial oxygen consumption (MVo(2)), and energetics/redox behavior in trabecular muscles from Zucker diabetic fatty (ZDF) rats. At baseline, force and corresponding iCa were lower in ZDF trabeculae than in controls. ISO decreased force in both groups in a dose-dependent manner. ISO did not affect iCa amplitude in controls, but ISO > 1.5% significantly reduced iCa amplitude in ZDF trabeculae. ISO-induced force depression fully recovered as a result of increased iCa when external Ca(2+) was raised in controls. However, both force and iCa remained low in ZDF muscle at elevated external Ca(2+). In controls, force, iCa, and MVo(2) increased when stimulation frequency was increased from 0.5 to 1.5 Hz. ZDF muscles, however, exhibited blunted responses in force and iCa and decreased MVo(2). Oxidative stress levels were unchanged in control muscles but increased significantly in ZDF muscles after exposure to ISO. Finally, the depressive effect of ISO was prevented by 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (Tempol) in ZDF muscles. These findings suggest that ISO dose-dependently attenuates force in control and ZDF muscles with differential effect on iCa. The mechanism of force depression by ISO in controls is mainly decreased myofilament Ca(2+) sensitivity, whereas in ZDF muscles the ISO-induced decrease in contraction is due to worsening oxidative stress, which inhibits iCa and force development.
Assuntos
Anestésicos Inalatórios/efeitos adversos , Diabetes Mellitus Experimental/metabolismo , Metabolismo Energético/efeitos dos fármacos , Isoflurano/efeitos adversos , Miocárdio/metabolismo , Obesidade/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Anestésicos Inalatórios/administração & dosagem , Animais , Cálcio/metabolismo , Diabetes Mellitus Experimental/complicações , Relação Dose-Resposta a Droga , Isoflurano/administração & dosagem , Obesidade/complicações , Consumo de Oxigênio/efeitos dos fármacos , Ratos , Ratos ZuckerRESUMO
Hidden genetic variations have the potential to lead to the evolution of new traits. Molecular chaperones, which assist protein folding, may conceal genetic variations in protein-coding regions. Here we investigate whether the chemical milieu of cells has the potential to alleviate intracellular protein folding, a possibility that could implicate osmolytes in concealing genetic variations. We found that the model osmolyte trimethylamine N-oxide (TMAO) can buffer mutations that impose kinetic traps in the folding pathways of two model proteins. Using this information, we rationally designed TMAO-dependent mutants in vivo, starting from a TMAO-independent protein. We show that different osmolytes buffer a unique spectrum of mutations. Consequently, the chemical milieu of cells may alter the folding pathways of unique mutant variants in polymorphic populations and lead to unanticipated spectra of genetic buffering.
Assuntos
Proteínas Ligantes de Maltose/química , Proteínas Ligantes de Maltose/genética , Metilaminas/farmacologia , Mutação/genética , Dobramento de Proteína/efeitos dos fármacos , Cinética , Proteínas Ligantes de Maltose/isolamento & purificação , Proteínas Ligantes de Maltose/metabolismo , Reação em Cadeia da PolimeraseRESUMO
INTRODUCTION: To evaluate the efficacy, safety, pharmacokinetics (PK), and immunogenicity of ZRC-3277 (pertuzumab biosimilar) with Perjeta® (pertuzumab) in previously untreated patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC). PATIENTS AND METHODS: This phase III, multicenter, double-blind study across 38 sites in India randomized (1:1) patients with HER2-positive MBC in either the ZRC-3277 or Perjeta® group. Both groups also received trastuzumab and docetaxel. Of 268 enrolled patients, mITT population had 243 patients (119 and 124 in the ZRC-3277 and Perjeta® groups, respectively). The primary objective was to compare the between-group objective response rate (ORR) after 6 cycles of treatment. ORR was determined by evaluating scans of computed tomography or magnetic resonance imaging following Response Evaluation Criteria in Solid Tumor (RECIST 1.1). Two-sided 95% confidence interval (95% CI) for the difference in ORR was determined to evaluate the noninferiority of ZRC-3277 to Perjeta®. The secondary outcomes included the assessment of PK, immunogenicity, and safety between the 2 groups. RESULTS: In the mITT population, 104 (87.39%) and 114 (91.94%) participants achieved the ORR in the ZRC-3277 and Perjeta® groups, respectively. For predefined -15% noninferiority margin, obtained 2-sided 95% CIs (-12.19%, 3.11%) for the difference in ORR (-4.55%) between the 2 groups demonstrated the noninferiority of ZRC-3277 to Perjeta®. PK, immunogenicity, and safety were not significantly different between the 2 groups. CONCLUSION: Efficacy, PK, immunogenicity, and safety profiles of ZRC-3277 was found to be similar to those of Perjeta®.
Assuntos
Anticorpos Monoclonais Humanizados , Medicamentos Biossimilares , Neoplasias da Mama , Receptor ErbB-2 , Humanos , Feminino , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Neoplasias da Mama/metabolismo , Receptor ErbB-2/metabolismo , Pessoa de Meia-Idade , Método Duplo-Cego , Índia , Medicamentos Biossimilares/uso terapêutico , Medicamentos Biossimilares/administração & dosagem , Medicamentos Biossimilares/efeitos adversos , Adulto , Anticorpos Monoclonais Humanizados/uso terapêutico , Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Monoclonais Humanizados/farmacocinética , Anticorpos Monoclonais Humanizados/efeitos adversos , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Antineoplásicos Imunológicos/uso terapêutico , Antineoplásicos Imunológicos/efeitos adversos , Antineoplásicos Imunológicos/farmacocinética , Resultado do Tratamento , Trastuzumab/uso terapêutico , Trastuzumab/administração & dosagem , Docetaxel/uso terapêutico , Docetaxel/administração & dosagemRESUMO
The coupled interactions among the fundamental carriers of charge, heat, and electromagnetic fields at interfaces and boundaries give rise to energetic processes that enable a wide array of technologies. The energy transduction among these coupled carriers results in thermal dissipation at these surfaces, often quantified by the thermal boundary resistance, thus driving the functionalities of the modern nanotechnologies that are continuing to provide transformational benefits in computing, communication, health care, clean energy, power recycling, sensing, and manufacturing, to name a few. It is the purpose of this Review to summarize recent works that have been reported on ultrafast and nanoscale energy transduction and heat transfer mechanisms across interfaces when different thermal carriers couple near or across interfaces. We review coupled heat transfer mechanisms at interfaces of solids, liquids, gasses, and plasmas that drive the resulting interfacial heat transfer and temperature gradients due to energy and momentum coupling among various combinations of electrons, vibrons, photons, polaritons (plasmon polaritons and phonon polaritons), and molecules. These interfacial thermal transport processes with coupled energy carriers involve relatively recent research, and thus, several opportunities exist to further develop these nascent fields, which we comment on throughout the course of this Review.
RESUMO
PURPOSE: Very few studies have demonstrated the rituximab biosimilarity in terms of efficacy, safety, pharmacokinetics, pharmacodynamics, and immunogenicity in patients with diffuse large B-cell lymphoma (DLBCL) in India. Therefore, we compared the efficacy, safety, pharmacokinetic, pharmacodynamic, and immunogenicity of our biosimilar rituximab with the reference rituximab (Ristova, Roche products [India] Pvt. Ltd) in patients with DLBCL in India. METHODS: A phase 3, randomized, assessor-blind, parallel-group, two-arm study was conducted across 28 sites in India. A total of 153 newly diagnosed DLBCL patients were randomized to receive either biosimilar rituximab or reference rituximab. The study drugs were administered at a dose of 375 mg/m2 by intravenous infusion every 3 weeks for six cycles. The primary end point was objective response rate (ORR) at the end of Cycle 6. Secondary end points included: pharmacokinetic, pharmacodynamics, immunogenicity, and safety assessment. RESULTS: The ORR at the end of Cycle 6 was 82.14% in the biosimilar rituximab and 85.71% in the reference rituximab group. The risk difference (90% CIs) was - 3.57 (- 14.80, 7.66). It met the non-inferiority margin of - 20%. The pharmacokinetic and pharmacodynamic parameters were comparable between the two treatment groups. The incidence rate of immunogenicity was very low and similar in both the treatment groups. The safety profile of both the treatments was comparable with no major difference in terms of nature, frequency and severity of TEAEs. CONCLUSION: The study demonstrated the biosimilarity between the biosimilar rituximab and the reference rituximab. Our biosimilar rituximab could add to the cost-effective treatment alternatives for patients with DLBCL in India.
Assuntos
Medicamentos Biossimilares , Linfoma Difuso de Grandes Células B , Humanos , Rituximab/efeitos adversos , Medicamentos Biossimilares/efeitos adversos , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/patologia , Infusões Intravenosas , Índia , Resultado do TratamentoRESUMO
We investigated the protective effects of Enicostemma littorale Blume (EL) extract on hypertension and insulin resistance along with its associated cardiovascular complications in high fructose (HF) fed rats. For this, rats were divided among 4 groups: (i) control, fed laboratory chow; (ii) fed with a high level of fructose; (iii) fed with a high level of fructose plus E. littorale extract; and (iv) fed with a high level of fructose plus rosiglitazone (Rg). EL and Rg treatments were given simultaneously with HF diet. The results show that untreated HF-fed rats showed altered oral glucose tolerance, increased fasting insulin, and increased fasting glucose. These rats also exhibited hypertriglyceridemia, moderate hypertension, platelet hyperaggregability, decreased prothrombin time, activated partial thromboplastin time, altered vascular reactivity, and increased serum levels of enzymes (creatine kinase, type muscle-brain (CK-MB), aspartate aminotransferase (SGOT), lactate dehydrogenase (LDH), and alanine aminotransferase (SGPT). This is the first demonstration of platelet hyperaggregation and prothrombotic alteration in HF-fed rats. HF-fed rats treated with EL showed improved insulin resistance, along with reduced hypertriglyceridemia, hypertension, platelet aggregability, blood coagulation, serum enzymes (CK-MB, SGOT, LDH and SGPT), and vascular reactivity. These effects of EL in HF-induced hypertensive rats might be associated with the suppression of hyperinsulinemia and hypertriglyceridemia, along with its antiatherogenic and antithrombogenic potential. These data indicate that the aqueous extract of EL has great therapeutic potential for the prevention and (or) management of insulin resistance and the associated hypertension.
Assuntos
Gentianaceae , Hipertensão/tratamento farmacológico , Fitoterapia/métodos , Extratos Vegetais/uso terapêutico , Animais , Anti-Hipertensivos/uso terapêutico , Biomarcadores/sangue , Coagulação Sanguínea/efeitos dos fármacos , Cardiotônicos/uso terapêutico , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/complicações , Doenças Cardiovasculares/tratamento farmacológico , Modelos Animais de Doenças , Frutose , Hipertensão/sangue , Hipertensão/complicações , Resistência à Insulina , Masculino , Agregação Plaquetária/efeitos dos fármacos , Contagem de Plaquetas/métodos , Ratos , Ratos EndogâmicosRESUMO
Biological sex is thought to influence mitochondrial bioenergetic function. Previous respiration measurements examining brain mitochondrial sex differences were made at atmospheric oxygen using isolated brain mitochondria. Oxygen is 160 mm Hg (21%) in the atmosphere, while the oxygen tension in the brain generally ranges from â¼5 to 45 mm Hg (â¼1-6% O2). This study tested the hypothesis that sex and/or brain physiological oxygen tension influence the mitochondrial bioenergetic properties of primary rat cortical astrocytes and microglia. Oxygen consumption was measured with a Seahorse XF24 cell respirometer in an oxygen-controlled environmental chamber. Strikingly, male astrocytes had a higher maximal respiration than female astrocytes when cultured and assayed at 3% O2. Three percent O2 yielded a low physiological dissolved O2 level of â¼1.2% (9.1 mm Hg) at the cell monolayer during culture and 1.2-3.0% O2 during assays. No differences in bioenergetic parameters were observed between male and female astrocytes at 21% O2 (dissolved O2 of â¼19.7%, 150 mm Hg during culture) or between either of these cell populations and female astrocytes at 3% O2. In contrast to astrocytes, microglia showed no sex differences in mitochondrial bioenergetic parameters at either oxygen level, regardless of whether they were non-stimulated or activated to a proinflammatory state. There were also no O2- or sex-dependent differences in proinflammatory TNF-α or IL-1ß cytokine secretion measured at 18 h activation. Overall, results reveal an intriguing sex variance in astrocytic maximal respiration that requires additional investigation. Findings also demonstrate that sex differences can be masked by conducting experiments at non-physiological O2.
Assuntos
Astrócitos/metabolismo , Encéfalo/metabolismo , Metabolismo Energético/fisiologia , Microglia/metabolismo , Mitocôndrias/metabolismo , Consumo de Oxigênio/fisiologia , Caracteres Sexuais , Animais , Animais Recém-Nascidos , Células Cultivadas , Feminino , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
Biallelic mutations in ATM result in the neurodegenerative syndrome Ataxia-Telangiectasia, while ATM haploinsufficiency increases the risk of cancer and other diseases. Previous studies revealed low reprogramming efficiency from A-T and carrier fibroblasts, a barrier to iPS cell-based modeling and regeneration. Here, we tested the feasibility of employing circulating erythroid cells, a compartment no or minimally affected in A-T, for the generation of A-T and carrier iPS cells. Our results indicate that episomal expression of Yamanaka factors plus BCL-xL in erythroid cells results in highly efficient iPS cell production in feeder-free, xeno-free conditions. Moreover, A-T iPS cells generated with this protocol maintain long-term replicative potential, stable karyotypes, re-elongated telomeres and capability to differentiate along the neural lineage in vitro and to form teratomas in vivo. Finally, we find that haploinsufficiency for ATM does not limit reprogramming from human erythroid cells or in vivo teratoma formation in the mouse.
Assuntos
Ataxia Telangiectasia/patologia , Reprogramação Celular , Células Eritroides/citologia , Células-Tronco Pluripotentes Induzidas/citologia , Adolescente , Animais , Ataxia Telangiectasia/genética , Ataxia Telangiectasia/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia/genética , Sequência de Bases , Diferenciação Celular , Linhagem Celular , Linhagem da Célula , Análise Mutacional de DNA , Células Eritroides/metabolismo , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/transplante , Cariótipo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Telômero/metabolismo , Encurtamento do Telômero , Teratoma/metabolismo , Teratoma/patologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Peripheral blood was obtained from a 12-year old male carrying bialleleic inactivating mutations at the ATM locus, causing Ataxia-Telangiectasia (A-T). Blood erythroid cells were briefly expanded in vitro and induced pluripotent stem cells (iPSCs) were generated via transfection with episomal vectors carrying hOCT4, hSOX2, hKLF4, hMYC and hBCL2L1. SF-003 iPSCs were free of genomically integrated reprogramming genes, had the specific compound heterozygous mutations, stable karyotype, expressed pluripotency markers and formed teratomas in immunodeficient (NOD scid gamma; NGS) mice. The SF-003 iPSC line may be a useful resource for in vitro modeling of A-T.
Assuntos
Ataxia Telangiectasia/patologia , Reprogramação Celular , Eritroblastos/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Animais , Ataxia Telangiectasia/genética , Ataxia Telangiectasia/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia/genética , Sequência de Bases , Diferenciação Celular , Linhagem Celular , Criança , Análise Mutacional de DNA , Eritroblastos/metabolismo , Éxons , Deleção de Genes , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/transplante , Cariótipo , Masculino , Camundongos , Camundongos Endogâmicos NOD , Teratoma/patologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transplante HeterólogoRESUMO
Reductive stress leads to the loss of disulfide bond formation and induces the unfolded protein response of the endoplasmic reticulum (UPR(ER)), necessary to regain proteostasis in the compartment. Here we show that peroxide accumulation during reductive stress attenuates UPR(ER) amplitude by altering translation without any discernible effect on transcription. Through a comprehensive genetic screen in Saccharomyces cerevisiae, we identify modulators of reductive stress-induced UPR(ER) and demonstrate that oxidative quality control (OQC) genes modulate this cellular response in the presence of chronic but not acute reductive stress. Using a combination of microarray and relative quantitative proteomics, we uncover a non-canonical translation attenuation mechanism that acts in a bipartite manner to selectively downregulate highly expressed proteins, decoupling the cell's transcriptional and translational response during reductive ER stress. Finally, we demonstrate that PERK, a canonical translation attenuator in higher eukaryotes, helps in bypassing a ROS-dependent, non-canonical mode of translation attenuation.
Assuntos
Estresse do Retículo Endoplasmático/genética , Retículo Endoplasmático/genética , Homeostase/genética , Biossíntese de Proteínas/genética , Animais , Caenorhabditis elegans/genética , Regulação para Baixo/genética , Eucariotos/genética , Peróxidos/metabolismo , Proteômica/métodos , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/fisiologia , Transcrição Gênica/genética , Resposta a Proteínas não Dobradas/genética , eIF-2 Quinase/genéticaRESUMO
SIGNIFICANCE: The heart depends on continuous mitochondrial ATP supply and maintained redox balance to properly develop force, particularly under increased workload. During diabetes, however, myocardial energetic-redox balance is perturbed, contributing to the systolic and diastolic dysfunction known as diabetic cardiomyopathy (DC). CRITICAL ISSUES: How these energetic and redox alterations intertwine to influence the DC progression is still poorly understood. Excessive bioavailability of both glucose and fatty acids (FAs) play a central role, leading, among other effects, to mitochondrial dysfunction. However, where and how this nutrient excess affects mitochondrial and cytoplasmic energetic/redox crossroads remains to be defined in greater detail. RECENT ADVANCES: We review how high glucose alters cellular redox balance and affects mitochondrial DNA. Next, we address how lipid excess, either stored in lipid droplets or utilized by mitochondria, affects performance in diabetic hearts by influencing cardiac energetic and redox assets. Finally, we examine how the reciprocal energetic/redox influence between mitochondrial and cytoplasmic compartments shapes myocardial mechanical activity during the course of DC, focusing especially on the glutathione and thioredoxin systems. FUTURE DIRECTIONS: Protecting mitochondria from losing their ability to generate energy, and to control their own reactive oxygen species emission is essential to prevent the onset and/or to slow down DC progression. We highlight mechanisms enforced by the diabetic heart to counteract glucose/FAs surplus-induced damage, such as lipid storage, enhanced mitochondria-lipid droplet interaction, and upregulation of key antioxidant enzymes. Learning more on the nature and location of mechanisms sheltering mitochondrial functions would certainly help in further optimizing therapies for human DC.
Assuntos
Diabetes Mellitus/metabolismo , Mitocôndrias Cardíacas/metabolismo , Miocárdio/metabolismo , Animais , DNA Mitocondrial/metabolismo , Cardiomiopatias Diabéticas/metabolismo , Ácidos Graxos/metabolismo , Glucose/metabolismo , Humanos , OxirreduçãoRESUMO
Current scientific debates center on the impact of lipids and mitochondrial function on diverse aspects of human health, nutrition and disease, among them the association of lipotoxicity with the onset of insulin resistance in skeletal muscle, and with heart dysfunction in obesity and diabetes. Mitochondria play a fundamental role in aging and in prevalent acute or chronic diseases. Lipids are main mitochondrial fuels however these molecules can also behave as uncouplers and inhibitors of oxidative phosphorylation. Knowledge about the functional composition of these contradictory effects and their impact on mitochondrial-cellular energetics/redox status is incomplete. Cells store fatty acids (FAs) as triacylglycerol and package them into cytoplasmic lipid droplets (LDs). New emerging data shows the LD as a highly dynamic storage pool of FAs that can be used for energy reserve. Lipid excess packaging into LDs can be seen as an adaptive response to fulfilling energy supply without hindering mitochondrial or cellular redox status and keeping low concentration of lipotoxic intermediates. Herein we review the mechanisms of action and utilization of lipids by mitochondria reported in liver, heart and skeletal muscle under relevant physiological situations, e.g., exercise. We report on perilipins, a family of proteins that associate with LDs in response to loading of cells with lipids. Evidence showing that in addition to physical contact, mitochondria and LDs exhibit metabolic interactions is presented and discussed. A hypothetical model of channeled lipid utilization by mitochondria is proposed. Direct delivery and channeled processing of lipids in mitochondria could represent a reliable and efficient way to maintain reactive oxygen species (ROS) within levels compatible with signaling while ensuring robust and reliable energy supply.
RESUMO
Persistent mullerian duct syndrome (PMDS) is a rare form of male pseudohermaphroditism in which mullerian duct derivatives are present in an otherwise normally differentiated 46 XY male. We report a case of a 33-year-old male with PMDS operated for postchemotherapy seminoma. A diagnosis of PMDS was made on subsequent histopathological evaluation.