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1.
Clin Gastroenterol Hepatol ; 21(6): 1598-1606.e5, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36642291

RESUMO

BACKGROUND & AIMS: Safety of biologic agents is a key consideration in patients with inflammatory bowel disease (IBD) and active or recent cancer. We compared the safety of tumor necrosis factor (TNF)-α antagonists vs non-TNF biologics in patients with IBD with active or recent cancer. METHODS: We conducted a multicenter retrospective cohort study of patients with IBD and either active cancer (cohort A) or recent prior cancer (within ≤5 years; cohort B) who were treated with TNFα antagonists or non-TNF biologics after their cancer diagnosis. Primary outcomes were progression-free survival (cohort A) or recurrence-free survival (cohort B). Safety was compared using inverse probability of treatment weighting with propensity scores. RESULTS: In cohort A, of 125 patients (483.8 person-years of follow-up evaluation) with active cancer (age, 54 ± 15 y, 75% solid-organ malignancy), 10 of 55 (incidence rate [IR] per 100 py, 4.4) and 9 of 40 (IR, 10.4) patients treated with TNFα antagonists and non-TNF biologics had cancer progression, respectively. There was no difference in the risk of progression-free survival between TNFα antagonists vs non-TNF biologics (hazard ratio, 0.76; 95% CI, 0.25-2.30). In cohort B, of 170 patients (513 person-years of follow-up evaluation) with recent prior cancer (age, 53 ± 15 y, 84% solid-organ malignancy; duration of remission, 19 ± 19 mo), 8 of 78 (IR, 3.4) and 5 of 66 (IR 3.7) patients treated with TNFα antagonists and non-TNF biologics had cancer recurrence, respectively. The risk of recurrence-free survival was similar between both groups (hazard ratio, 0.94; 95% CI, 0.24-3.77). CONCLUSIONS: In patients with IBD with active or recent cancer, TNFα antagonists and non-TNF biologics have comparable safety. The choice of biologic should be dictated by IBD disease severity in collaboration with an oncologist.


Assuntos
Produtos Biológicos , Doenças Inflamatórias Intestinais , Neoplasias , Humanos , Adulto , Pessoa de Meia-Idade , Idoso , Fator de Necrose Tumoral alfa , Fatores Biológicos , Estudos Retrospectivos , Doenças Inflamatórias Intestinais/tratamento farmacológico , Doenças Inflamatórias Intestinais/induzido quimicamente , Neoplasias/epidemiologia , Neoplasias/induzido quimicamente , Inibidores do Fator de Necrose Tumoral , Produtos Biológicos/efeitos adversos
2.
Nucleic Acids Res ; 49(18): e105, 2021 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-34255842

RESUMO

Translation of eukaryotic mRNAs begins with binding of their m7G cap to eIF4E, followed by recruitment of other translation initiation factor proteins. We describe capCLIP, a novel method to comprehensively capture and quantify the eIF4E (eukaryotic initiation factor 4E) 'cap-ome' and apply it to examine the biological consequences of eIF4E-cap binding in distinct cellular contexts. First, we use capCLIP to identify the eIF4E cap-omes in human cells with/without the mTORC1 (mechanistic target of rapamycin, complex 1) inhibitor rapamycin, there being an emerging consensus that rapamycin inhibits translation of TOP (terminal oligopyrimidine) mRNAs by displacing eIF4E from their caps. capCLIP reveals that the representation of TOP mRNAs in the cap-ome is indeed systematically reduced by rapamycin, thus validating our new methodology. capCLIP also refines the requirements for a functional TOP sequence. Second, we apply capCLIP to probe the consequences of phosphorylation of eIF4E. We show eIF4E phosphorylation reduces overall eIF4E-mRNA association and, strikingly, causes preferential dissociation of mRNAs with short 5'-UTRs. capCLIP is a valuable new tool to probe the function of eIF4E and of other cap-binding proteins such as eIF4E2/eIF4E3.


Assuntos
Fator de Iniciação 4E em Eucariotos/metabolismo , Capuzes de RNA/metabolismo , RNA Mensageiro/metabolismo , Células HeLa , Humanos , Ligação Proteica , Biossíntese de Proteínas
3.
Clin Gastroenterol Hepatol ; 20(2): 455-457, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-33647465

RESUMO

Microscopic colitis (MC) is a disease characterized by chronic watery diarrhea secondary to colonic inflammation. Endoscopically, the mucosa is usually normal but biopsies show characteristic histologic findings.1.


Assuntos
Colite Microscópica , Colite , Anticorpos Monoclonais Humanizados/uso terapêutico , Biópsia , Doença Crônica , Colite/tratamento farmacológico , Colite/patologia , Colite Microscópica/tratamento farmacológico , Colite Microscópica/patologia , Diarreia/tratamento farmacológico , Diarreia/patologia , Humanos
4.
Cell Mol Life Sci ; 78(1): 249-270, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32170339

RESUMO

eIF4E plays key roles in protein synthesis and tumorigenesis. It is phosphorylated by the kinases MNK1 and MNK2. Binding of MNKs to eIF4G enhances their ability to phosphorylate eIF4E. Here, we show that mTORC1, a key regulator of mRNA translation and oncogenesis, directly phosphorylates MNK2 on Ser74. This suppresses MNK2 activity and impairs binding of MNK2 to eIF4G. These effects provide a novel mechanism by which mTORC1 signaling impairs the function of MNK2 and thereby decreases eIF4E phosphorylation. MNK2[S74A] knock-in cells show enhanced phosphorylation of eIF4E and S6K1 (i.e., increased mTORC1 signaling), enlarged cell size, and increased invasive and transformative capacities. MNK2[Ser74] phosphorylation was inversely correlated with disease progression in human prostate tumors. MNK inhibition exerted anti-proliferative effects in prostate cancer cells in vitro. These findings define a novel feedback loop whereby mTORC1 represses MNK2 activity and oncogenic signaling through eIF4E phosphorylation, allowing reciprocal regulation of these two oncogenic pathways.


Assuntos
Fator de Iniciação 4E em Eucariotos/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Fator de Iniciação 4E em Eucariotos/antagonistas & inibidores , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina/antagonistas & inibidores , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Morfolinas/farmacologia , Mutagênese Sítio-Dirigida , Fosforilação/efeitos dos fármacos , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Ligação Proteica , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/genética , Transdução de Sinais/efeitos dos fármacos , Proteína 2 do Complexo Esclerose Tuberosa/genética , Proteína 2 do Complexo Esclerose Tuberosa/metabolismo
5.
Matern Child Health J ; 26(10): 1976-1982, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36002697

RESUMO

INTRODUCTION: Despite significant improvements in recent years, maternal and neonatal health outcomes remain poor in many regions of the world. One such area is in the remote mountainous regions of Nepal. The purpose of this study is to describe the current antenatal care practices and delivery support in a mountainous district of Nepal. METHODS: This study took place in Solukhumbu District between December 2015 and February 2018. A household survey was created using evidence-based maternal and neonatal care indicators. Women who had delivered within the previous two years were surveyed regarding antenatal and delivery care they received. A standardized health facility survey was used to evaluate the operational status of health facilities. The study was approved by the Nepal Ministry of Health and the University of Utah IRB. RESULTS: A total of 487 households and 19 facilities were surveyed. 35.7% (174/487) of deliveries occurred in a health facility (hospital, primary health care center or birthing center). 35.2% (171/486) of deliveries were attended by a skilled birth attendant. 52.8% (47/89) of women who did not deliver in a facility noted that transportation issues and not having sufficient time to travel during labor prevented them from delivering in a facility. No health posts had staff trained in obstetric and neonatal emergencies. DISCUSSION: The majority of women in Solukhumbu District do not receive high quality antenatal and delivery care. An intervention that would make antenatal care and delivery support more accessible could improve maternal and infant outcomes in this district and other similar regions.


Assuntos
Centros de Assistência à Gravidez e ao Parto , Serviços de Saúde Materna , Assistência Perinatal , Criança , Parto Obstétrico , Feminino , Instalações de Saúde , Acessibilidade aos Serviços de Saúde , Humanos , Recém-Nascido , Nepal/epidemiologia , Gravidez , Cuidado Pré-Natal
6.
J Neurochem ; 157(4): 1086-1101, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-32892352

RESUMO

The regulation of protein synthesis is a vital and finely tuned process in cellular physiology. In neurons, this process is very precisely regulated, as which mRNAs undergo translation is highly dependent on context. One of the most prominent regulators of protein synthesis is the enzyme eukaryotic elongation factor kinase 2 (eEF2K) that regulates the elongation stage of protein synthesis. This kinase and its substrate, eukaryotic elongation factor 2 (eEF2) are important in processes such as neuronal development and synaptic plasticity. eEF2K is regulated by multiple mechanisms including Ca2+ -ions and the mTORC1 signaling pathway, both of which play key roles in neurological processes such as learning and memory. In such settings, the localized control of protein synthesis is of crucial importance. In this work, we sought to investigate how the localization of eEF2K is controlled and the impact of this on protein synthesis in neuronal cells. In this study, we used both SH-SY5Y neuroblastoma cells and mouse cortical neurons, and pharmacologically and/or genetic approaches to modify eEF2K function. We show that eEF2K activity and localization can be regulated by its binding partner Homer1b/c, a scaffolding protein known for its participation in calcium-regulated signaling pathways. Furthermore, our results indicate that this interaction is regulated by the mTORC1 pathway, through a known phosphorylation site in eEF2K (S396), and that it affects rates of localized protein synthesis at synapses depending on the presence or absence of this scaffolding protein.


Assuntos
Quinase do Fator 2 de Elongação/metabolismo , Proteínas de Arcabouço Homer/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Neurônios/metabolismo , Biossíntese de Proteínas/fisiologia , Animais , Bicuculina/farmacologia , Células Cultivadas , Antagonistas de Receptores de GABA-A/farmacologia , Humanos , Camundongos , Fosforilação , Biossíntese de Proteínas/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos
7.
Trends Biochem Sci ; 41(10): 847-858, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27527252

RESUMO

The eukaryotic translation initiation factor (eIF) 4E, which binds to the 5'-cap of mRNA, undergoes phosphorylation on a single conserved serine, executed by the mitogen-activated protein kinase (MAPK)-interacting kinases (MNKs). However, the functional consequences and physiological roles of MNK signalling have remained obscure. Now, new pharmacological and genetic tools have provided unprecedented insights into the function of MNKs and eIF4E phosphorylation. The studies suggest that MNKs control the translation of specific mRNAs in cancer metastasis and neuronal synaptic plasticity by a novel mechanism involving the regulation of the translational repressor, cytoplasmic fragile-X protein-interacting protein 1 (CYFIP1). These recent breakthroughs go a long way to resolving the longstanding enigma and controversy surrounding the function of the MNK-eIF4E axis in cancer cell biology and neurobiology.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Fator de Iniciação 4E em Eucariotos/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias/genética , Biossíntese de Proteínas , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Fator de Iniciação 4E em Eucariotos/metabolismo , Humanos , Metástase Neoplásica , Neoplasias/metabolismo , Neoplasias/patologia , Plasticidade Neuronal , Fosforilação , Ligação Proteica , Capuzes de RNA/genética , Capuzes de RNA/metabolismo , Transdução de Sinais , Sinapses/genética , Sinapses/metabolismo
9.
Development ; 144(20): 3744-3754, 2017 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-28893946

RESUMO

The islets of Langerhans are endocrine organs characteristically dispersed throughout the pancreas. During development, endocrine progenitors delaminate, migrate radially and cluster to form islets. Despite the distinctive distribution of islets, spatially localized signals that control islet morphogenesis have not been discovered. Here, we identify a radial signaling axis that instructs developing islet cells to disperse throughout the pancreas. A screen of pancreatic extracellular signals identified factors that stimulated islet cell development. These included semaphorin 3a, a guidance cue in neural development without known functions in the pancreas. In the fetal pancreas, peripheral mesenchymal cells expressed Sema3a, while central nascent islet cells produced the semaphorin receptor neuropilin 2 (Nrp2). Nrp2 mutant islet cells developed in proper numbers, but had defects in migration and were unresponsive to purified Sema3a. Mutant Nrp2 islets aggregated centrally and failed to disperse radially. Thus, Sema3a-Nrp2 signaling along an unrecognized pancreatic developmental axis constitutes a chemoattractant system essential for generating the hallmark morphogenetic properties of pancreatic islets. Unexpectedly, Sema3a- and Nrp2-mediated control of islet morphogenesis is strikingly homologous to mechanisms that regulate radial neuronal migration and cortical lamination in the developing mammalian brain.


Assuntos
Ilhotas Pancreáticas/citologia , Neuropilina-2/metabolismo , Semaforina-3A/metabolismo , Animais , Adesão Celular , Movimento Celular , Fatores Quimiotáticos/química , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Ligantes , Camundongos , Camundongos Knockout , Morfogênese , Mutação , Neurônios/metabolismo , Neuropilina-2/genética , Pâncreas/citologia , Semaforina-3A/genética , Transdução de Sinais
11.
EMBO J ; 33(18): 2040-56, 2014 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-25069772

RESUMO

The microRNAs of the miR-200 family maintain the central characteristics of epithelia and inhibit tumor cell motility and invasiveness. Using the Ago-HITS-CLIP technology for transcriptome-wide identification of direct microRNA targets in living cells, along with extensive validation to verify the reliability of the approach, we have identified hundreds of miR-200a and miR-200b targets, providing insights into general features of miRNA target site selection. Gene ontology analysis revealed a predominant effect of miR-200 targets in widespread coordinate control of actin cytoskeleton dynamics. Functional characterization of the miR-200 targets indicates that they constitute subnetworks that underlie the ability of cancer cells to migrate and invade, including coordinate effects on Rho-ROCK signaling, invadopodia formation, MMP activity, and focal adhesions. Thus, the miR-200 family maintains the central characteristics of the epithelial phenotype by acting on numerous targets at multiple levels, encompassing both cytoskeletal effectors that control actin filament organization and dynamics, and upstream signals that locally regulate the cytoskeleton to maintain cell morphology and prevent cell migration.


Assuntos
Movimento Celular , Proliferação de Células , Células Epiteliais/fisiologia , Regulação da Expressão Gênica , Redes Reguladoras de Genes , MicroRNAs/genética , MicroRNAs/metabolismo , Linhagem Celular , Citoesqueleto/metabolismo , Humanos
12.
Nature ; 489(7416): 447-51, 2012 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-22810588

RESUMO

Epigenetic information is frequently erased near the start of each new generation. In some cases, however, epigenetic information can be transmitted from parent to progeny (multigenerational epigenetic inheritance). A particularly notable example of this type of epigenetic inheritance is double-stranded RNA-mediated gene silencing in Caenorhabditis elegans. This RNA-mediated interference (RNAi) can be inherited for more than five generations. To understand this process, here we conduct a genetic screen for nematodes defective in transmitting RNAi silencing signals to future generations. This screen identified the heritable RNAi defective 1 (hrde-1) gene. hrde-1 encodes an Argonaute protein that associates with small interfering RNAs in the germ cells of progeny of animals exposed to double-stranded RNA. In the nuclei of these germ cells, HRDE-1 engages the nuclear RNAi defective pathway to direct the trimethylation of histone H3 at Lys 9 (H3K9me3) at RNAi-targeted genomic loci and promote RNAi inheritance. Under normal growth conditions, HRDE-1 associates with endogenously expressed short interfering RNAs, which direct nuclear gene silencing in germ cells. In hrde-1- or nuclear RNAi-deficient animals, germline silencing is lost over generational time. Concurrently, these animals exhibit steadily worsening defects in gamete formation and function that ultimately lead to sterility. These results establish that the Argonaute protein HRDE-1 directs gene-silencing events in germ-cell nuclei that drive multigenerational RNAi inheritance and promote immortality of the germ-cell lineage. We propose that C. elegans use the RNAi inheritance machinery to transmit epigenetic information, accrued by past generations, into future generations to regulate important biological processes.


Assuntos
Proteínas Argonautas/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/genética , Epigênese Genética/genética , Células Germinativas/metabolismo , Padrões de Herança/genética , Proteínas Nucleares/metabolismo , Animais , Núcleo Celular/genética , Núcleo Celular/metabolismo , Células Germinativas/citologia , Interferência de RNA , RNA de Cadeia Dupla/genética , RNA de Cadeia Dupla/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo
13.
J Strength Cond Res ; 31(10): 2765-2776, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-27893478

RESUMO

Power training has become a common exercise intervention for improving muscle strength, power, and physical function while reducing injury risk. Few studies, however, have evaluated acute load changes on power output during traditional resistance training protocols. Therefore, the aim of this study was to quantify the effects of different loading patterns on power output during a single session of circuit resistance training (CRT). Nine male (age = 19.4 ± 0.9 years) and 11 female participants (age = 20.6 ± 1.6 years) completed 3 CRT protocols during separate testing sessions using 7 pneumatic exercises. Protocols included heavy load explosive contraction (HLEC: 80% one repetition maximum [1RM], maximum speed concentric-2 seconds eccentric), heavy load controlled contraction (HLCC: 80% 1RM, 2 seconds concentric-2 seconds eccentric), and moderate load explosive contraction (MLEC: 50% 1RM, maximum speed concentric-2 seconds eccentric). Protocols were assigned randomly using a counterbalanced design. Power for each repetition and set were determined using computerized software interfaced with each machine. Blood lactate was measured at rest and immediately postexercise. For male and female participants, average power was significantly greater during all exercises for HLEC and MLEC than HLCC. Average power was greatest during the HLEC for leg press (LP), hip adduction (ADD), and hip abduction (ABD) (p ≤ 0.05), whereas male participants alone produced their greatest power during HLEC for leg curl (LC) (p < 0.001). For male and female participants, significantly greater power was detected by set for LP, lat pull-down (LAT), ADD, LC, and ABD for the MLEC protocol (p < 0.02) and for LP, LAT, CP, and LC for the HLEC protocol (p < 0.03). A condition × sex interaction was seen for blood lactate changes ((Equation is included in full-text article.)= 0.249; p = 0.024), with female participants producing a significantly greater change for MLEC than HLEC (Mdiff = 1.61 ± 0.35 mmol·L; p = 0.011), whereas male participants showed no significant differences among conditions. Performing a CRT protocol using explosive training patterns, especially at high loads for lower-body exercises and moderate loads for upper-body exercises, produces significantly higher power than controlled speed training in most exercises. These results provide exercisers, personal trainers, and strength coaches with information that can assist in the design of training protocols to maximize power output during CRT.


Assuntos
Exercícios em Circuitos/métodos , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Treinamento Resistido/métodos , Levantamento de Peso/fisiologia , Adolescente , Humanos , Masculino , Adulto Jovem
15.
Nature ; 465(7301): 1097-101, 2010 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-20543824

RESUMO

Eukaryotic cells express a wide variety of endogenous small regulatory RNAs that regulate heterochromatin formation, developmental timing, defence against parasitic nucleic acids and genome rearrangement. Many small regulatory RNAs are thought to function in nuclei. For instance, in plants and fungi, short interfering RNA (siRNAs) associate with nascent transcripts and direct chromatin and/or DNA modifications. To understand further the biological roles of small regulatory RNAs, we conducted a genetic screen to identify factors required for RNA interference (RNAi) in Caenorhabditis elegans nuclei. Here we show that the gene nuclear RNAi defective-2 (nrde-2) encodes an evolutionarily conserved protein that is required for siRNA-mediated silencing in nuclei. NRDE-2 associates with the Argonaute protein NRDE-3 within nuclei and is recruited by NRDE-3/siRNA complexes to nascent transcripts that have been targeted by RNAi. We find that nuclear-localized siRNAs direct an NRDE-2-dependent silencing of pre-messenger RNAs (pre-mRNAs) 3' to sites of RNAi, an NRDE-2-dependent accumulation of RNA polymerase (RNAP) II at genomic loci targeted by RNAi, and NRDE-2-dependent decreases in RNAP II occupancy and RNAP II transcriptional activity 3' to sites of RNAi. These results define NRDE-2 as a component of the nuclear RNAi machinery and demonstrate that metazoan siRNAs can silence nuclear-localized RNAs co-transcriptionally. In addition, these results establish a novel mode of RNAP II regulation: siRNA-directed recruitment of NRDE factors that inhibit RNAP II during the elongation phase of transcription.


Assuntos
Caenorhabditis elegans/genética , Interferência de RNA , RNA Polimerase II/antagonistas & inibidores , RNA de Helmintos/metabolismo , RNA Interferente Pequeno/metabolismo , Transcrição Gênica , Animais , Caenorhabditis elegans/enzimologia , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Núcleo Celular/genética , Núcleo Celular/metabolismo , Sequência Conservada , Genes de Helmintos/genética , Ligação Proteica , RNA Polimerase II/metabolismo , Precursores de RNA/genética , Precursores de RNA/metabolismo , RNA de Helmintos/biossíntese , RNA de Helmintos/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Transcrição Gênica/genética
16.
Alcohol Alcohol ; 51(6): 698-701, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27267907

RESUMO

AIM: To assess alcohol use after liver transplantation (LT) and compare liver transplant recipients for alcoholic liver disease (ALD) with recipients for non-ALD causes. METHODS: National Institute of Diabetes and Digestive and Kidney Diseases liver transplant database stratified to ALD and non-ALD causes. RESULTS: Among 488 LT recipients reporting pre-transplant alcohol use (147 ALD), proportion of LT recipients reporting alcohol use was similar comparing ALD and non-ALD transplants (25.4% vs. 27.2%; P = 0.56). Among ALD transplants, of 31 with alcohol use, 23 (74%) relapsed at ≥2 year, 25 (80%) reported intermittent drinking and 4 (13%) reported heavy drinking. Among Non-ALD recipients, alcohol use was equally distributed to within 2, 2-5 and after 5 years of LT with 82% reporting intermittent drinking and 9% heavy drinking. Patients with pre-transplant drinking of >20 years and abstinence duration of <2 years were over 2.5-fold likely to report post-transplant alcohol use compared to drinking of >20 years and abstinence of >2 years, 2.56 [95% CI: 1.41-4.67]. Etiology (ALD vs. non-ALD) did not predict post-transplant alcohol use. Of 139 ALD patients with follow-up biopsy data, 13 (7 with post-transplant alcohol use) had steatohepatitis. Histology on 319 non-ALD recipients showed recurrent disease in 91, none due to alcohol. Overall survival was similar between drinkers and abstainers (71% vs. 66%; P = 0.35). Recurrent ALD was cause of death in one ALD and none of non-ALD patients. CONCLUSION: Alcohol use after LT is independent of LT indication. Patients with non-ALD etiology should be carefully screened for alcohol use prior to LT to identify those at risk for post-LT alcohol use.


Assuntos
Consumo de Bebidas Alcoólicas/epidemiologia , Hepatopatias/etiologia , Transplante de Fígado , Consumo de Bebidas Alcoólicas/psicologia , Feminino , Humanos , Hepatopatias/cirurgia , Hepatopatias Alcoólicas/epidemiologia , Hepatopatias Alcoólicas/psicologia , Transplante de Fígado/psicologia , Transplante de Fígado/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Prevalência
17.
J Biomech Eng ; 137(4): 041005, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25588057

RESUMO

Intraluminal thrombus (ILT) in abdominal aortic aneurysms (AAA) has potential implications to aneurysm growth and rupture risk; yet, the mechanisms underlying its development remain poorly understood. Some researchers have proposed that ILT development may be driven by biomechanical platelet activation within the AAA, followed by adhesion in regions of low wall shear stress. Studies have investigated wall shear stress levels within AAA, but platelet activation potential (AP) has not been quantified. In this study, patient-specific computational fluid dynamic (CFD) models were used to analyze stress-induced AP within AAA under rest and exercise flow conditions. The analysis was conducted using Lagrangian particle-based and Eulerian continuum-based approaches, and the results were compared. Results indicated that biomechanical platelet activation is unlikely to play a significant role for the conditions considered. No consistent trend was observed in comparing rest and exercise conditions, but the functional dependence of AP on stress magnitude and exposure time can have a large impact on absolute levels of anticipated platelet AP. The Lagrangian method obtained higher peak AP values, although this difference was limited to a small percentage of particles that falls below reported levels of physiologic background platelet activation.


Assuntos
Aneurisma da Aorta Abdominal/fisiopatologia , Fenômenos Mecânicos , Ativação Plaquetária , Fenômenos Biomecânicos , Análise de Elementos Finitos , Hidrodinâmica , Modelos Cardiovasculares
18.
Proc Natl Acad Sci U S A ; 108(49): 19683-8, 2011 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-22106253

RESUMO

RNA interference (RNAi) is heritable in Caenorhabditis elegans; the progeny of C. elegans exposed to dsRNA inherit the ability to silence genes that were targeted by RNAi in the previous generation. Here we investigate the mechanism of RNAi inheritance in C. elegans. We show that exposure of animals to dsRNA results in the heritable expression of siRNAs and the heritable deposition of histone 3 lysine 9 methylation (H3K9me) marks in progeny. siRNAs are detectable before the appearance of H3K9me marks, suggesting that chromatin marks are not directly inherited but, rather, reestablished in inheriting progeny. Interestingly, H3K9me marks appear more prominently in inheriting progeny than in animals directly exposed to dsRNA, suggesting that germ-line transmission of silencing signals may enhance the efficiency of siRNA-directed H3K9me. Finally, we show that the nuclear RNAi (Nrde) pathway maintains heritable RNAi silencing in C. elegans. The Argonaute (Ago) NRDE-3 associates with heritable siRNAs and, acting in conjunction with the nuclear RNAi factors NRDE-1, NRDE-2, and NRDE-4, promotes siRNA expression in inheriting progeny. These results demonstrate that siRNA expression is heritable in C. elegans and define an RNAi pathway that promotes the maintenance of RNAi silencing and siRNA expression in the progeny of animals exposed to dsRNA.


Assuntos
Caenorhabditis elegans/genética , Núcleo Celular/genética , Proteínas de Fluorescência Verde/genética , Interferência de RNA , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans/embriologia , Caenorhabditis elegans/crescimento & desenvolvimento , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Núcleo Celular/metabolismo , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Fluorescência Verde/metabolismo , Histonas/metabolismo , Padrões de Herança , Lisina/metabolismo , Masculino , Metilação , Microscopia de Fluorescência , Mutação , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
19.
PLoS Genet ; 7(8): e1002249, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21901112

RESUMO

In plants and fungi, small RNAs silence gene expression in the nucleus by establishing repressive chromatin states. The role of endogenous small RNAs in metazoan nuclei is largely unknown. Here we show that endogenous small interfering RNAs (endo-siRNAs) direct Histone H3 Lysine 9 methylation (H3K9me) in Caenorhabditis elegans. In addition, we report the identification and characterization of nuclear RNAi defective (nrde)-1 and nrde-4. Endo-siRNA-driven H3K9me requires the nuclear RNAi pathway including the Argonaute (Ago) NRDE-3, the conserved nuclear RNAi factor NRDE-2, as well as NRDE-1 and NRDE-4. Small RNAs direct NRDE-1 to associate with the pre-mRNA and chromatin of genes, which have been targeted by RNAi. NRDE-3 and NRDE-2 are required for the association of NRDE-1 with pre-mRNA and chromatin. NRDE-4 is required for NRDE-1/chromatin association, but not NRDE-1/pre-mRNA association. These data establish that NRDE-1 is a novel pre-mRNA and chromatin-associating factor that links small RNAs to H3K9 methylation. In addition, these results demonstrate that endo-siRNAs direct chromatin modifications via the Nrde pathway in C. elegans.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Cromatina/genética , Proteínas Nucleares/metabolismo , Precursores de RNA/genética , RNA Interferente Pequeno/genética , Proteínas de Ligação a RNA/metabolismo , Animais , Proteínas de Caenorhabditis elegans/genética , Cromatina/metabolismo , Metilação de DNA/genética , Histonas/genética , Histonas/metabolismo , Lisina/genética , Proteínas Nucleares/genética , Proteínas de Ligação a RNA/genética
20.
Proc Natl Acad Sci U S A ; 108(26): 10562-7, 2011 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-21670280

RESUMO

Evidence of endoplasmic reticulum (ER) stress has been found in lungs of patients with familial and sporadic idiopathic pulmonary fibrosis. We tested whether ER stress causes or exacerbates lung fibrosis by (i) conditional expression of a mutant form of surfactant protein C (L188Q SFTPC) found in familial interstitial pneumonia and (ii) intratracheal treatment with the protein misfolding agent tunicamycin. We developed transgenic mice expressing L188Q SFTPC exclusively in type II alveolar epithelium by using the Tet-On system. Expression of L188Q SFTPC induced ER stress, as determined by increased expression of heavy-chain Ig binding protein (BiP) and splicing of X-box binding protein 1 (XBP1) mRNA, but no lung fibrosis was identified in the absence of a second profibrotic stimulus. After intratracheal bleomycin, L188Q SFTPC-expressing mice developed exaggerated lung fibrosis and reduced static lung compliance compared with controls. Bleomycin-treated L188Q SFTPC mice also demonstrated increased apoptosis of alveolar epithelial cells and greater numbers of fibroblasts in the lungs. With a complementary model, intratracheal tunicamycin treatment failed to induce lung remodeling yet resulted in augmentation of bleomycin-induced fibrosis. These data support the concept that ER stress produces a dysfunctional epithelial cell phenotype that facilitates fibrotic remodeling. ER stress pathways may serve as important therapeutic targets in idiopathic pulmonary fibrosis.


Assuntos
Retículo Endoplasmático/metabolismo , Pulmão/patologia , Fibrose Pulmonar/patologia , Animais , Apoptose/genética , Bleomicina/toxicidade , Peptídeos e Proteínas de Sinalização Intercelular , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Camundongos , Camundongos Transgênicos , Mutação , Peptídeos/genética , Fibrose Pulmonar/genética , Fibrose Pulmonar/metabolismo , Proteína C Associada a Surfactante Pulmonar , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Tunicamicina/toxicidade
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