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1.
Nature ; 558(7711): 605-609, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29925953

RESUMEN

Reprogramming of mRNA translation has a key role in cancer development and drug resistance 1 . However, the molecular mechanisms that are involved in this process remain poorly understood. Wobble tRNA modifications are required for specific codon decoding during translation2,3. Here we show, in humans, that the enzymes that catalyse modifications of wobble uridine 34 (U34) tRNA (U34 enzymes) are key players of the protein synthesis rewiring that is induced by the transformation driven by the BRAF V600E oncogene and by resistance to targeted therapy in melanoma. We show that BRAF V600E -expressing melanoma cells are dependent on U34 enzymes for survival, and that concurrent inhibition of MAPK signalling and ELP3 or CTU1 and/or CTU2 synergizes to kill melanoma cells. Activation of the PI3K signalling pathway, one of the most common mechanisms of acquired resistance to MAPK therapeutic agents, markedly increases the expression of U34 enzymes. Mechanistically, U34 enzymes promote glycolysis in melanoma cells through the direct, codon-dependent, regulation of the translation of HIF1A mRNA and the maintenance of high levels of HIF1α protein. Therefore, the acquired resistance to anti-BRAF therapy is associated with high levels of U34 enzymes and HIF1α. Together, these results demonstrate that U34 enzymes promote the survival and resistance to therapy of melanoma cells by regulating specific mRNA translation.


Asunto(s)
Codón/genética , Resistencia a Antineoplásicos/efectos de los fármacos , Resistencia a Antineoplásicos/genética , Melanoma/tratamiento farmacológico , Melanoma/genética , Biosíntesis de Proteínas , Animales , Proteínas Portadoras/química , Proteínas Portadoras/metabolismo , Línea Celular Tumoral , Codón/efectos de los fármacos , Femenino , Humanos , Masculino , Diana Mecanicista del Complejo 2 de la Rapamicina/metabolismo , Melanoma/patología , Melanoma Experimental/tratamiento farmacológico , Melanoma Experimental/genética , Melanoma Experimental/patología , Ratones , Ratones Endogámicos NOD , Ratones SCID , Fosforilación , Biosíntesis de Proteínas/efectos de los fármacos , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Proteínas Proto-Oncogénicas B-raf/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN de Transferencia/química , ARN de Transferencia/genética , ARN de Transferencia/metabolismo , Transducción de Señal , Factores de Elongación Transcripcional , Uridina/química , Uridina/genética , Uridina/metabolismo , Vemurafenib/farmacología , Vemurafenib/uso terapéutico , Pez Cebra/genética
2.
Nucleic Acids Res ; 50(22): 12768-12789, 2022 12 09.
Artículo en Inglés | MEDLINE | ID: mdl-36477312

RESUMEN

Genotoxic agents, that are used in cancer therapy, elicit the reprogramming of the transcriptome of cancer cells. These changes reflect the cellular response to stress and underlie some of the mechanisms leading to drug resistance. Here, we profiled genome-wide changes in pre-mRNA splicing induced by cisplatin in breast cancer cells. Among the set of cisplatin-induced alternative splicing events we focused on COASY, a gene encoding a mitochondrial enzyme involved in coenzyme A biosynthesis. Treatment with cisplatin induces the production of a short isoform of COASY lacking exons 4 and 5, whose depletion impedes mitochondrial function and decreases sensitivity to cisplatin. We identified RBM39 as a major effector of the cisplatin-induced effect on COASY splicing. RBM39 also controls a genome-wide set of alternative splicing events partially overlapping with the cisplatin-mediated ones. Unexpectedly, inactivation of RBM39 in response to cisplatin involves its interaction with the AP-1 family transcription factor c-Jun that prevents RBM39 binding to pre-mRNA. Our findings therefore uncover a novel cisplatin-induced interaction between a splicing regulator and a transcription factor that has a global impact on alternative splicing and contributes to drug resistance.


Asunto(s)
Empalme Alternativo , Cisplatino , Resistencia a Antineoplásicos , Proteínas de Unión al ARN , Factores de Transcripción , Empalme Alternativo/genética , Cisplatino/farmacología , Cisplatino/metabolismo , Daño del ADN , Proteínas Nucleares/metabolismo , Precursores del ARN/genética , Precursores del ARN/metabolismo , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Factores de Transcripción/metabolismo , Línea Celular Tumoral , Humanos , Animales
3.
Nat Mater ; 21(6): 640-646, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35552524

RESUMEN

Ferrimagnetic alloys are model systems for understanding the ultrafast magnetization switching in materials with antiferromagnetically coupled sublattices. Here we investigate the dynamics of the rare-earth and transition-metal sublattices in ferrimagnetic GdFeCo and TbCo dots excited by spin-orbit torques with combined temporal, spatial and elemental resolution. We observe distinct switching regimes in which the magnetizations of the two sublattices either remain synchronized throughout the reversal process or switch following different trajectories in time and space. In the latter case, we observe a transient ferromagnetic state that lasts up to 2 ns. The asynchronous switching of the two magnetizations is ascribed to the master-agent dynamics induced by the spin-orbit torques on the transition-metal and rare-earth sublattices and their weak antiferromagnetic coupling, which depends sensitively on the alloy microstructure. Larger antiferromagnetic exchange leads to faster switching and shorter recovery of the magnetization after a current pulse. Our findings provide insight into the dynamics of ferrimagnets and the design of spintronic devices with fast and uniform switching.

4.
Nano Lett ; 22(14): 5916-5921, 2022 07 27.
Artículo en Inglés | MEDLINE | ID: mdl-35834181

RESUMEN

Metamaterial-assisted illumination nanoscopy (MAIN) has been proven to be a promising approach for super-resolution microscopy with up to a 7-fold improvement in imaging resolution. Further resolution enhancement is possible in principle, however, has not yet been demonstrated due to the lack of high-quality ultrathin layered hyperbolic metamaterials (HMMs) used in the MAIN. Here, we fabricate a low-loss composite HMM consisting of high-quality bilayers of Al-doped Ag and MgO with a nominal thickness of 2.5 nm, and then use it to demonstrate an ultrathin layered hyperbolic metamaterial-assisted illumination nanoscopy (ULH-MAIN) with a 14-fold imaging resolution improvement. This improvement of resolution is achieved in fluorescent beads super-resolution experiments and verified with scanning electron microscopy. The ULH-MAIN presents a simple super-resolution imaging approach that offers distinct benefits such as low illumination power, low cost, and a broad spectrum of selectable probes, making it ideal for dynamic imaging of life science samples.


Asunto(s)
Iluminación , Microscopía
6.
Phys Rev Lett ; 127(16): 167202, 2021 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-34723598

RESUMEN

We report on the occurrence of strong interlayer Dzyaloshinskii-Moriya interaction (DMI) between an in-plane magnetized Co layer and a perpendicularly magnetized TbFe layer through a Pt spacer. The DMI causes a chiral coupling that favors one-handed orthogonal magnetic configurations of Co and TbFe, which we reveal through Hall effect and magnetoresistance measurements. The DMI coupling mediated by Pt causes effective magnetic fields on either layer of up to 10-15 mT, which decrease monotonically with increasing Pt thickness. Ru, Ta, and Ti spacers mediate a significantly smaller coupling compared to Pt, highlighting the essential role of Pt in inducing the interlayer DMI. These results are relevant to understand and maximize the interlayer coupling induced by the DMI as well as to design spintronic devices with chiral spin textures.

7.
Phys Rev Lett ; 126(25): 257201, 2021 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-34241498

RESUMEN

Spin transport via magnon diffusion in magnetic insulators is important for a broad range of spin-based phenomena and devices. However, the absence of the magnon equivalent of an electric force is a bottleneck. In this Letter, we demonstrate the controlled generation of magnon drift currents in heterostructures of yttrium iron garnet and platinum. By performing electrical injection and detection of incoherent magnons, we find magnon drift currents that stem from the interfacial Dzyaloshinskii-Moriya interaction. We can further control the magnon drift by the orientation of the magnetic field. The drift current changes the magnon propagation length by up to ±6% relative to diffusion. We generalize the magnonic spin transport theory to include a finite drift velocity resulting from any inversion asymmetric interaction and obtain results consistent with our experiments.

8.
J Mol Cell Cardiol ; 135: 149-159, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31442470

RESUMEN

The mitral valve is a complex multilayered structure populated by fibroblast-like cells, valvular interstitial cells (VIC) which are embedded in an extracellular matrix (ECM) scaffold and are submitted to the mechanical deformations affecting valve at each heartbeat, for an average of 40 million times per year. Myxomatous mitral valve (MMV) is the most frequent heart valve disease characterized by disruption of several valvular structures due to alterations of their ECM preventing the complete closure of the valve resulting in symptoms of prolapse and regurgitation. VIC and their ECM exhibit reciprocal dynamic processes between the mechanical signals issued from the ECM and the modulation of VIC phenotype responsible for ECM homeostasis of the valve. Abnormal perception and responsiveness of VIC to mechanical stress may induce an inappropriate adaptative remodeling of the valve progressively leading to MMV. To investigate the response of human VIC to mechanical strain and identify the molecular mechanisms of mechano-transduction in these cells, a cyclic equibiaxial elongation of 14% at the cardiac frequency of 1.16 Hz was applied to VIC by using a Flexercell-4000 T™ apparatus for increasing time (from 1 h to 8 h). We showed that cyclic stretch induces an early (1 h) and transient over-expression of TGFß2 and αSMA. CTGF, a profibrotic growth factor promoting the synthesis of ECM components, was strongly induced after 1 and 2 h of stretching and still upregulated at 8 h. The mechanical stress-induced CTGF up-regulation was dependent on RhoC, but not RhoA, as demonstrated by siRNA-mediated silencing approaches, and further supported by evidencing RhoC activation upon cell stretching and suppression of cell response by pharmacological inhibition of the effector ROCK1/2. It was also dependent on the MEK/Erk1/2 pathway which was activated by mechanical stress independently of RhoC and ROCK. Finally, mechanical stretching induced the nuclear translocation of myocardin related transcription factor-A (MRTF-A) which forms a transcriptional complex with SRF to promote the expression of target genes, notably CTGF. Treatment of stretched cultures with inhibitors of the identified pathways (ROCK1/2, MEK/Erk1/2, MRTF-A translocation) blocked CTGF overexpression and abrogated the increased MRTF-A nuclear translocation. CTGF is up-regulated in many pathological processes involving mechanically challenged organs, promotes ECM accumulation and is considered as a hallmark of fibrotic diseases. Pharmacological targeting of MRTF-A by newly developed inhibitors may represent a relevant therapy for MMV.


Asunto(s)
Estenosis de la Válvula Aórtica/genética , Calcinosis/genética , Fibrosis/genética , Válvula Mitral/metabolismo , Válvula Aórtica/metabolismo , Válvula Aórtica/patología , Estenosis de la Válvula Aórtica/patología , Calcinosis/patología , Fibrosis/patología , Humanos , Sistema de Señalización de MAP Quinasas/genética , Válvula Mitral/patología , Estrés Mecánico , Transactivadores/genética , Quinasas Asociadas a rho/genética , Proteína de Unión al GTP rhoA/genética
9.
Breast Cancer Res ; 21(1): 11, 2019 01 23.
Artículo en Inglés | MEDLINE | ID: mdl-30674353

RESUMEN

BACKGROUND: Elevated aerobic glycolysis rate is a biochemical alteration associated with malignant transformation and cancer progression. This metabolic shift unavoidably generates methylglyoxal (MG), a potent inducer of dicarbonyl stress through the formation of advanced glycation end products (AGEs). We have previously shown that the silencing of glyoxalase 1 (GLO1), the main MG detoxifying enzyme, generates endogenous dicarbonyl stress resulting in enhanced growth and metastasis in vivo. However, the molecular mechanisms through which MG stress promotes metastasis development remain to be unveiled. METHODS: In this study, we used RNA sequencing analysis to investigate gene-expression profiling of GLO1-depleted breast cancer cells and we validated the regulated expression of selected genes of interest by RT-qPCR. Using in vitro and in vivo assays, we demonstrated the acquisition of a pro-metastatic phenotype related to dicarbonyl stress in MDA-MB-231, MDA-MB-468 and MCF7 breast cancer cellular models. Hyperactivation of MEK/ERK/SMAD1 pathway was evidenced using western blotting upon endogenous MG stress and exogenous MG treatment conditions. MEK and SMAD1 regulation of MG pro-metastatic signature genes in breast cancer cells was demonstrated by RT-qPCR. RESULTS: High-throughput transcriptome profiling of GLO1-depleted breast cancer cells highlighted a pro-metastatic signature that establishes novel connections between MG dicarbonyl stress, extracellular matrix (ECM) remodeling by neoplastic cells and enhanced cell migration. Mechanistically, we showed that these metastasis-related processes are functionally linked to MEK/ERK/SMAD1 cascade activation in breast cancer cells. We showed that sustained MEK/ERK activation in GLO1-depleted cells notably occurred through the down-regulation of the expression of dual specificity phosphatases in MG-stressed breast cancer cells. The use of carnosine and aminoguanidine, two potent MG scavengers, reversed MG stress effects in in vitro and in vivo experimental settings. CONCLUSIONS: These results uncover for the first time the key role of MG dicarbonyl stress in the induction of ECM remodeling and the activation of migratory signaling pathways, both in favor of enhanced metastatic dissemination of breast cancer cells. Importantly, the efficient inhibition of mitogen-activated protein kinase (MAPK) signaling using MG scavengers further emphasizes the need to investigate their therapeutic potential across different malignancies.


Asunto(s)
Neoplasias de la Mama/metabolismo , Regulación Neoplásica de la Expresión Génica , Sistema de Señalización de MAP Quinasas/genética , Piruvaldehído/metabolismo , Animales , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Línea Celular Tumoral , Movimiento Celular/genética , Regulación hacia Abajo , Fosfatasas de Especificidad Dual/metabolismo , Femenino , Perfilación de la Expresión Génica , Técnicas de Silenciamiento del Gen , Glucólisis/genética , Humanos , Lactoilglutatión Liasa/genética , Lactoilglutatión Liasa/metabolismo , Ratones , ARN Interferente Pequeño/metabolismo , Proteína Smad1/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto
10.
CMAJ ; 190(12): E347-E354, 2018 03 26.
Artículo en Inglés | MEDLINE | ID: mdl-29581161

RESUMEN

BACKGROUND: Patients who continue to smoke after acute coronary syndrome are at increased risk of reinfarction and death. We previously found use of varenicline to increase abstinence 24 weeks after acute coronary syndrome; here we report results through 52 weeks. METHODS: The EVITA trial was a multicentre, double-blind, randomized, placebo-controlled trial of varenicline for smoking cessation in patients admitted to hospital with acute coronary syndrome. Participants were randomly assigned (1:1) to receive varenicline or placebo for 12 weeks, in conjunction with low-intensity counselling. Smoking abstinence was assessed via 7-day recall, with biochemical validation using exhaled carbon monoxide. Participants lost to follow-up or withdrawn were assumed to have returned to smoking. RESULTS: Among the 302 participants, abstinence declined over the course of the trial, with 34.4% abstinent 52 weeks after acute coronary syndrome. Compared with placebo, point estimates suggest use of varenicline increased point-prevalence abstinence (39.9% v. 29.1%, difference 10.7%, 95% confidence interval [CI] 0.01% to 21.44%; number needed to treat 10), continuous abstinence (31.1% v. 21.2%, difference 9.9%, 95% CI -0.01% to 19.8%) and reduction in daily cigarette smoking by 50% or greater (57.8% v. 49.7%, difference 8.1%, 95% CI -3.1% to 19.4%). Varenicline and placebo groups had similar occurrence of serious adverse events (24.5% v. 21.9%, risk difference 2.7%, 95% CI -7.3% to 12.6%) and major adverse cardiovascular events (8.6% v. 9.3%, risk difference -0.7%, 95% CI -7.8% to 6.5%). INTERPRETATION: Varenicline was efficacious for smoking cessation in this high-risk patient population. However, 60% of patients who received treatment with varenicline still returned to smoking. Trial registration: ClinicalTrials.gov, no. NCT00794573.


Asunto(s)
Síndrome Coronario Agudo/terapia , Agonistas Nicotínicos/administración & dosificación , Cese del Hábito de Fumar/métodos , Fumar/tratamiento farmacológico , Vareniclina/administración & dosificación , Síndrome Coronario Agudo/epidemiología , Anciano , Canadá/epidemiología , Método Doble Ciego , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Agonistas Nicotínicos/efectos adversos , Fumar/epidemiología , Tasa de Supervivencia , Vareniclina/efectos adversos
11.
Circulation ; 133(1): 21-30, 2016 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-26553744

RESUMEN

BACKGROUND: Less than one-third of smokers hospitalized with an acute coronary syndrome (ACS) remain abstinent following discharge. We assessed whether varenicline, begun in-hospital, is efficacious for smoking cessation following ACS. METHODS AND RESULTS: We conducted a multi-center, double-blind, randomized, placebo-controlled trial in which smokers hospitalized with an ACS were randomized to varenicline or placebo for 12 weeks. All patients received low-intensity counseling. The primary end point was point-prevalence smoking abstinence assessed at 24 weeks by 7-day recall and biochemical validation using expired carbon monoxide. A total of 302 patients were randomized (mean age 55±9 years; 75% male; 56% ST-segment elevation myocardial infarction; 38% non-ST-segment elevation myocardial infarction; 6% unstable angina). Patients smoked a mean of 21±11 cigarettes/d at the time of hospitalization and had been smoking for a mean of 36±12 years. At 24 weeks, patients randomized to varenicline had significantly higher rates of smoking abstinence and reduction than patients randomized to placebo. Point-prevalence abstinence rates were 47.3% in the varenicline group and 32.5% in the placebo group (P=0.012; number needed to treat=6.8). Continuous abstinence rates were 35.8% and 25.8%, respectively (P=0.081; number needed to treat=10.0), and rates of reduction ≥50% in daily cigarette consumption were 67.4% and 55.6%, respectively (P=0.05; number needed to treat=8.5). Adverse event rates within 30 days of study drug discontinuation were similar between groups (serious adverse events: varenicline 11.9%, placebo 11.3%; major adverse cardiovascular events: varenicline 4.0%, placebo 4.6%). CONCLUSIONS: Varenicline, initiated in-hospital following ACS, is efficacious for smoking cessation. Future studies are needed to establish safety in these patients. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00794573.


Asunto(s)
Síndrome Coronario Agudo/tratamiento farmacológico , Hospitalización , Agonistas Nicotínicos/uso terapéutico , Cese del Hábito de Fumar/métodos , Dispositivos para Dejar de Fumar Tabaco , Vareniclina/uso terapéutico , Síndrome Coronario Agudo/diagnóstico , Método Doble Ciego , Femenino , Estudios de Seguimiento , Hospitalización/tendencias , Humanos , Masculino , Persona de Mediana Edad , Dispositivos para Dejar de Fumar Tabaco/tendencias
12.
Catheter Cardiovasc Interv ; 89(2): 169-177, 2017 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-27148802

RESUMEN

OBJECTIVE: To assess safety and feasibility of autologous adipose-derived regenerative cells (ADRCs), for treatment of chronic ischemic cardiomyopathy patients. BACKGROUND: Preclinical and early clinical trials suggest ADRCs have excellent potential for ischemic conditions. METHODS: The Athena program consisted of two parallel, prospective, randomized (2:1, active: placebo), double-blind trials assessing intramyocardial (IM) ADRC delivery [40-million, n = 28 (ATHENA) and 80-million (ATHENA II) cells, n = 3]). Patients with an EF ≥20% but ≤45%, multivessel coronary artery disease (CAD) not amenable to revascularization, inducible ischemia, and symptoms of either angina (CCS II-IV) or heart failure (NYHA Class II-III) on maximal medical therapy were enrolled. All patients underwent fat harvest procedure (≤450 mL adipose), on-site cell processing (Celution® System, Cytori Therapeutics), electromechanical mapping, and IM delivery of ADRCs or placebo. RESULTS: Enrollment was terminated prematurely due to non-ADRC-related adverse events and subsequent prolonged enrollment time. Thirty-one patients (17-ADRCs, 14-placebo) mean age 65 ± 8 years, baseline LVEF(%) 31.1 ± 8.7 (ADRC), 31.8 ± 7.7 (placebo) were enrolled. Change in V02 max favored ADRCs (+45.4 ± 222 vs. -9.5 ± 137 mL/min) but there was no difference in left ventricular function or volumes. At 12-months, heart failure hospitalizations occurred in 2/17 (11.7%) [ADRC] and 3/14 (21.4%) [placebo]. Differences in NYHA and CCS classes favored ADRCs at 12-months with significant improvement in MLHFQ (-21.6 + 13.9 vs. -5.5 + 23.8, P = 0.038). CONCLUSIONS: A small volume fat harvest, automated local processing, and IM delivery of autologous ADRCs is feasible with suggestion of benefit in "no option" CAD patients. Although the sample size is limited, the findings support feasibility and scalability for treatment of ischemic cardiomyopathy with ADRCs. © 2016 Wiley Periodicals, Inc.


Asunto(s)
Tejido Adiposo/citología , Isquemia Miocárdica/cirugía , Miocardio/patología , Regeneración , Trasplante de Células Madre , Disfunción Ventricular Izquierda/cirugía , Función Ventricular Izquierda , Anciano , Enfermedad Crónica , Progresión de la Enfermedad , Método Doble Ciego , Terminación Anticipada de los Ensayos Clínicos , Estudios de Factibilidad , Femenino , Insuficiencia Cardíaca/etiología , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/terapia , Humanos , Masculino , Persona de Mediana Edad , Isquemia Miocárdica/diagnóstico por imagen , Isquemia Miocárdica/patología , Isquemia Miocárdica/fisiopatología , Readmisión del Paciente , Estudios Prospectivos , Recuperación de la Función , Trasplante de Células Madre/efectos adversos , Volumen Sistólico , Factores de Tiempo , Trasplante Autólogo , Resultado del Tratamiento , Estados Unidos , Disfunción Ventricular Izquierda/diagnóstico por imagen , Disfunción Ventricular Izquierda/patología , Disfunción Ventricular Izquierda/fisiopatología
13.
Circ Res ; 114(10): 1564-8, 2014 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-24812350

RESUMEN

To understand the role of bone marrow mononuclear cells in the treatment of acute myocardial infarction, this overview offers a retrospective examination of strengths and limitations of 3 contemporaneous trials with attention to critical design features and provides an analysis of the combined data set and implications for future directions in cell therapy for acute myocardial infarction.


Asunto(s)
Trasplante de Médula Ósea/métodos , Leucocitos Mononucleares/trasplante , Infarto del Miocardio/patología , Infarto del Miocardio/cirugía , Trasplante de Médula Ósea/tendencias , Tratamiento Basado en Trasplante de Células y Tejidos/métodos , Tratamiento Basado en Trasplante de Células y Tejidos/tendencias , Ensayos Clínicos como Asunto/métodos , Ensayos Clínicos como Asunto/tendencias , Bases de Datos Factuales/tendencias , Humanos , Leucocitos Mononucleares/patología , Leucocitos Mononucleares/fisiología , Estudios Retrospectivos , Volumen Sistólico/fisiología , Resultado del Tratamiento
14.
Ecotoxicology ; 25(2): 291-301, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26661591

RESUMEN

Limited data are available on the effects of molybdenum (Mo) on avian wildlife, which impairs evaluation of ecological exposure and risk. While Mo is an essential trace nutrient in birds, little is known of its toxicity to birds exposed to molybdenum disulfide (MoS2), the predominant form found in molybdenite ore. The chemical form and bioavailability of Mo is important in determining its toxicity. Avian toxicity tests typically involve a soluble form of Mo, such as sodium molybdate dihydrate (SMD, Na2MoO4·2H2O); however MoS2 is generally insoluble, with low bioaccessibility under most environmental conditions. The current study monitored survival and general health (body weight and food consumption) of 9-day old northern bobwhite exposed to soluble Mo (SMD) and ore-related Mo (MoS2) in their diet for 30 days. Toxicity and bioavailability (e.g. tissue distribution) of the two Mo forms were compared. Histopathology evaluations and serum, kidney, liver, and bone tissue sample analyses were conducted. Copper, a nutrient integrally associated with Mo toxicity, was also measured in the diet and tissue. No treatment-related mortality occurred and no treatment-related lesions were recorded for either Mo form. Tissue analyses detected increased Mo concentrations in serum, kidney, liver, and bone tissues following exposure to SMD, with decreasing concentrations following a post-exposure period. For the soluble form, a No-Observed-Adverse-Effect Concentration (NOAEC) of 1200 mg Mo as SMD/kg feed (134 mg SMD/kg body weight/day) was identified based on body weight and food consumption. No adverse effects were observed in birds exposed to MoS2 at the maximum dose of 5000 mg MoS2/kg feed (545 mg MoS2/kg body weight/day). These results show that effects associated with MoS2, the more environmentally prevalent and less bioavailable Mo form, are much less than those observed for SMD. These data should support more realistic representations of exposure and risks to avian receptors from environmental Mo.


Asunto(s)
Colinus/metabolismo , Disulfuros/toxicidad , Molibdeno/toxicidad , Contaminantes del Suelo/toxicidad , Animales , Colinus/crecimiento & desarrollo , Conducta Alimentaria/efectos de los fármacos , Femenino , Longevidad/efectos de los fármacos , Masculino , Aumento de Peso/efectos de los fármacos
15.
BMC Cancer ; 15: 227, 2015 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-25884497

RESUMEN

BACKGROUND: Modification of splicing by chemotherapeutic drugs has usually been evaluated on a limited number of pre-mRNAs selected for their recognized or potential importance in cell proliferation or apoptosis. However, the pathways linking splicing alterations to the efficiency of cancer therapy remain unclear. METHODS: Next-generation sequencing was used to analyse the transcriptome of breast carcinoma cells treated by cisplatin. Pharmacological inhibitors, RNA interference, cells deficient in specific signalling pathways, RT-PCR and FACS analysis were used to investigate how the anti-cancer drug cisplatin affected alternative splicing and the cell death pathway. RESULTS: We identified 717 splicing events affected by cisplatin, including 245 events involving cassette exons. Gene ontology analysis indicates that cell cycle, mRNA processing and pre-mRNA splicing were the main pathways affected. Importantly, the cisplatin-induced splicing alterations required class I PI3Ks P110ß but not components such as ATM, ATR and p53 that are involved in the DNA damage response. The siRNA-mediated depletion of the splicing regulator SRSF4, but not SRSF6, expression abrogated many of the splicing alterations as well as cell death induced by cisplatin. CONCLUSION: Many of the splicing alterations induced by cisplatin are caused by SRSF4 and they contribute to apoptosis in a process requires class I PI3K.


Asunto(s)
Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Cisplatino/farmacología , Precursores del ARN/genética , Empalme del ARN/efectos de los fármacos , Proteínas de Unión al ARN/metabolismo , Línea Celular Tumoral , Biología Computacional , Daño del ADN , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Proteínas Oncogénicas/genética , Proteínas Oncogénicas/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Procesamiento Postranscripcional del ARN/efectos de los fármacos , Factores de Empalme Serina-Arginina , Transducción de Señal/efectos de los fármacos , Factores de Transcripción/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo
16.
FASEB J ; 28(9): 4077-87, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24903274

RESUMEN

Bone cells exposed to real microgravity display alterations of their cytoskeleton and focal adhesions, two major mechanosensitive structures. These structures are controlled by small GTPases of the Ras homology (Rho) family. We investigated the effects of RhoA, Rac1, and Cdc42 modulation of osteoblastic cells under microgravity conditions. Human MG-63 osteoblast-like cells silenced for RhoGTPases were cultured in the automated Biobox bioreactor (European Space Agency) aboard the Foton M3 satellite and compared to replicate ground-based controls. The cells were fixed after 69 h of microgravity exposure for postflight analysis of focal contacts, F-actin polymerization, vascular endothelial growth factor (VEGF) expression, and matrix targeting. We found that RhoA silencing did not affect sensitivity to microgravity but that Rac1 and, to a lesser extent, Cdc42 abrogation was particularly efficient in counteracting the spaceflight-related reduction of the number of focal contacts [-50% in silenced, scrambled (SiScr) controls vs. -15% for SiRac1], the number of F-actin fibers (-60% in SiScr controls vs. -10% for SiRac1), and the depletion of matrix-bound VEGF (-40% in SiScr controls vs. -8% for SiRac1). Collectively, these data point out the role of the VEGF/Rho GTPase axis in mechanosensing and validate Rac1-mediated signaling pathways as potential targets for counteracting microgravity effects.


Asunto(s)
Fenómenos Fisiológicos Celulares , Osteoblastos/metabolismo , ARN Interferente Pequeño/genética , Ingravidez , Proteína de Unión al GTP cdc42/metabolismo , Proteína de Unión al GTP rac1/metabolismo , Proteína de Unión al GTP rhoA/metabolismo , Actinas/metabolismo , Células Cultivadas , Citoesqueleto/metabolismo , Sensación de Gravedad , Humanos , Mecanotransducción Celular , Microtúbulos/metabolismo , Osteoblastos/citología , ARN Mensajero/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal , Vuelo Espacial , Factor A de Crecimiento Endotelial Vascular/genética , Factor A de Crecimiento Endotelial Vascular/metabolismo , Proteína de Unión al GTP cdc42/antagonistas & inhibidores , Proteína de Unión al GTP cdc42/genética , Proteína de Unión al GTP rac1/antagonistas & inhibidores , Proteína de Unión al GTP rac1/genética , Proteína de Unión al GTP rhoA/antagonistas & inhibidores , Proteína de Unión al GTP rhoA/genética
17.
Angiogenesis ; 16(2): 353-71, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23254820

RESUMEN

VEGF-A is a crucial growth factor for blood vessel homeostasis and pathological angiogenesis. Due to alternative splicing of its pre-mRNA, VEGF-A is produced under several isoforms characterized by the combination of their C-terminal domains, which determines their respective structure, availability and affinity for co-receptors. As controversies still exist about the specific roles of these exon-encoded domains, we systematically compared the properties of eight natural and artificial variants containing the domains encoded by exons 1-4 and various combinations of the domains encoded by exons 5, 7 and 8a or 8b. All the variants (VEGF111a, VEGF111b, VEGF121a, VEGF121b, VEGF155a, VEGF155b, VEGF165a, VEGF165b) have a similar affinity for VEGF-R2, as determined by Surface plasmon resonance analyses. They strongly differ however in terms of binding to neuropilin-1 and heparin/heparan sulfate proteoglycans. Data indicate that the 6 amino acids encoded by exon 8a must be present and cooperate with those of exons 5 or 7 for efficient binding, which was confirmed in cell culture models. We further showed that VEGF165b has inhibitory effects in vitro, as previously reported, but that the shortest VEGF variant possessing also the 6 amino acids encoded by exon 8b (VEGF111b) is remarkably proangiogenic, demonstrating the critical importance of domain interactions for defining the VEGF properties. The number, size and localization of newly formed blood vessels in a model of tumour angiogenesis strongly depend also on the C-terminal domain composition, suggesting that association of several VEGF isoforms may be more efficient for treating ischemic diseases than the use of any single variant.


Asunto(s)
Neovascularización Patológica , Transducción de Señal/fisiología , Factor A de Crecimiento Endotelial Vascular/fisiología , Empalme Alternativo , Secuencia de Bases , Western Blotting , Permeabilidad Capilar , Clonación Molecular , Cartilla de ADN , Células HEK293 , Humanos , Inmunohistoquímica , Ligandos , Fosforilación , Unión Proteica , Proteolisis , Resonancia por Plasmón de Superficie , Factor A de Crecimiento Endotelial Vascular/química , Factor A de Crecimiento Endotelial Vascular/genética , Factor A de Crecimiento Endotelial Vascular/metabolismo
18.
Res Sports Med ; 21(1): 78-89, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23286424

RESUMEN

The purpose of this investigation was to compare sexes for time to fatigue at 100% VO(2)peak in recreationally trained individuals. Ten men (age: 23.4 ± 1.8; height: 177 ± 6.7; body mass: 83.8 ± 11.3; ± SD) and nine women (age: 25.0 ± 2.5; height: 165.6 ± 5.5; body mass: 62.7 ± 6.7) participated in this investigation after providing written consent. One week after assessing VO(2)peak, subjects exercised on an electrically braked cycle ergometer at 100% of VO(2)peak until fatigue. The time taken to fatigue was 48.9% longer for men than women (274 ± 13s vs. 184 ± 14s; p < 0.001, for men and women, respectively). When normalized for fat free mass (ffm; s/kg ffm) no significant differences between men and women were observed (3.99 ± 0.21s/kg ffm vs. 3.72 ± 0.28s/kg ffm for men and women, respectively, p = 0.431). The difference in fatigability between the sexes at this exercise intensity is to a large degree related to the difference in fat free mass.


Asunto(s)
Composición Corporal , Fatiga Muscular/fisiología , Consumo de Oxígeno , Resistencia Física/fisiología , Adulto , Prueba de Esfuerzo , Femenino , Humanos , Modelos Lineales , Masculino , Factores Sexuales , Factores de Tiempo
19.
NPJ Microgravity ; 9(1): 91, 2023 Dec 16.
Artículo en Inglés | MEDLINE | ID: mdl-38104197

RESUMEN

In space, cells sustain strong modifications of their mechanical environment. Mechanosensitive molecules at the cell membrane regulate mechanotransduction pathways that induce adaptive responses through the regulation of gene expression, post-translational modifications, protein interactions or intracellular trafficking, among others. In the current study, human osteoblastic cells were cultured on the ISS in microgravity and at 1 g in a centrifuge, as onboard controls. RNAseq analyses showed that microgravity inhibits cell proliferation and DNA repair, stimulates inflammatory pathways and induces ferroptosis and senescence, two pathways related to ageing. Morphological hallmarks of senescence, such as reduced nuclear size and changes in chromatin architecture, proliferation marker distribution, tubulin acetylation and lysosomal transport were identified by immunofluorescence microscopy, reinforcing the hypothesis of induction of cell senescence in microgravity during space flight. These processes could be attributed, at least in part, to the regulation of YAP1 and its downstream effectors NUPR1 and CKAP2L.

20.
JMIR Res Protoc ; 12: e51643, 2023 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-37707939

RESUMEN

BACKGROUND: Maori are the Indigenous people of Aotearoa (New Zealand). Despite global acceptance that cervical cancer is almost entirely preventable through vaccination and screening, wahine Maori (Maori women) are more likely to have cervical cancer and 2.5 times more likely to die from it than non-Maori women. Rural Maori residents diagnosed with cervical cancer have worse outcomes than urban residents. Living in rural Aotearoa means experiencing barriers to appropriate and timely health care, resulting from distance, the lack of community resourcing, and low prioritization of rural needs by the health system and government. These barriers are compounded by the current screening processes and referral pathways that create delays at each step. Screening for high-risk human papillomavirus (hrHPV) and point-of-care (POC) testing are scientific advances used globally to prevent cervical cancer. OBJECTIVE: This study aims to compare acceptability, feasibility, timeliness, referral to, and attendance for colposcopy following hrHPV detection between a community-controlled pathway and standard care. METHODS: This is a cluster randomized crossover trial, with 2 primary care practices (study sites) as clusters. Each site was randomized to implement either pathway 1 or 2, with crossover occurring at 15 months. Pathway 1 (community-controlled pathway) comprises HPV self-testing, 1-hour POC results, face-to-face information, support, and immediate referral to colposcopy for women with a positive test result. Pathway 2 (standard care) comprises HPV self-testing, laboratory analysis, usual results giving, information, support, and standard referral pathways for women with a positive test result. The primary outcome is the proportion of women with hrHPV-positive results having a colposcopy within 20 working days of the HPV test (national performance indicator). Qualitative research will analyze successes and challenges of both pathways from the perspectives of governance groups, clinical staff, women, and their family. This information will directly inform the new National Cervical Screening Program. RESULTS: In the first 15-month period, 743 eligible HPV self-tests were performed: 370 in pathway 1 with POC testing and 373 in pathway 2 with laboratory testing. The positivity rate for hrHPV was 7.3% (54/743). Data collection for the second period, qualitative interviews, and analyses are ongoing. CONCLUSIONS: This Maori-centered study combines quantitative and qualitative research to compare 2 clinical pathways from detection of hrHPV to colposcopy. This protocol draws on rural community practices strengths, successfully engaging Maori from a whanau ora (family wellness) approach including kanohi ki te kanohi (face-to-face), kaiawhina (nonclinical community health workers), and multiple venues for interventions. It will inform the theory and practice of rural models of the use of innovative technology, addressing Maori cervical cancer inequities and facilitating Maori wellness. The findings are anticipated to be applicable to other Indigenous and rural people in high-income countries. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12621000553875; https://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12621000553875. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/51643.

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