147 research outputs found
Non-canonical translation initiation of proteins with potential relevance in colorectal cancer
Internal Ribosome Entry Site (IRES)-Mediated Translation and Its Potential for Novel mRNA-Based Therapy Development
This article belongs to the Special Issue mRNA Metabolism in Health and Disease 2.0.Many conditions can benefit from RNA-based therapies, namely, those targeting internal ribosome entry sites (IRESs) and their regulatory proteins, the IRES trans-acting factors (ITAFs). IRES-mediated translation is an alternative mechanism of translation initiation, known for maintaining protein synthesis when canonical translation is impaired. During a stress response, it contributes to cell reprogramming and adaptation to the new environment. The relationship between IRESs and ITAFs with tumorigenesis and resistance to therapy has been studied in recent years, proposing new therapeutic targets and treatments. In addition, IRES-dependent translation initiation dysregulation is also related to neurological and cardiovascular diseases, muscular atrophies, or other syndromes. The participation of these structures in the development of such pathologies has been studied, yet to a far lesser extent than in cancer. Strategies involving the disruption of IRES-ITAF interactions or the modification of ITAF expression levels may be used with great impact in the development of new therapeutics. In this review, we aim to comprehend the current data on groups of human pathologies associated with IRES and/or ITAF dysregulation and their application in the designing of new therapeutic approaches using them as targets or tools. Thus, we wish to summarise the evidence in the field hoping to open new promising lines of investigation toward personalised treatments.This work was partially supported by UID/MULTI/04046/2019 Research Unit grant
(to BioISI)info:eu-repo/semantics/publishedVersio
Internal Ribosome Entry Site-Dependent Translation Dysregulation-Related Diseases
ReviewThis entry is adapted from 10.3390/biomedicines10081865 (http://repositorio.insa.pt/handle/10400.18/8440)Internal ribosome entry site (IRES)-mediated translation is an alternative mechanism of translation
initiation, known for maintaining protein synthesis when canonical translation is impaired. During a
stress response, it contributes to cell reprogramming and adaptation to the new environment.info:eu-repo/semantics/publishedVersio
Prevenção e cuidados em saúde oral em crianças de 0 a 6 anos
Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas MonizA importância de enfatizar a promoção da saúde oral em crianças fundamenta-se não apenas na intenção de educar a sociedade sobre conceitos e práticas de saúde oral, mas também na prevenção de doenças que podem ter repercussões negativas no bem-estar infantil. Neste contexto, o estudo da prevenção e cuidados em saúde oral em crianças de 0 a 6 anos trará uma visão geral sobre os métodos preventivos, bem como as principais condições que acometem a cavidade oral nessa faixa etária. O presente estudo teve como objetivo abordar a importância da prevenção de doenças orais na infância, investigando os fatores de risco associados e os mecanismos subjacentes ao seu desenvolvimento. Adicionalmente, serão discutidos métodos de cuidados em saúde oral com o intuito de avaliar seu impacto positivo na vida das crianças através da adoção de práticas de saúde. O método utilizado para a pesquisa foi através de uma revisão bibliográfica narrativa, recorrendo aos motores de busca online SciELO, PubMed, B-On e Google Acadêmico, em português e inglês para artigos de revisão, reporte de casos e revisões sistemáticas. As principais medidas preventivas adotadas para garantir uma saúde oral adequada ao longo da vida incluem, aconselhamento pré-natal e tratamentos dentários na gestante, primeira consulta do bebê entre os 6 meses a 1 ano de idade estabelecendo assim o “dental home”, aleitamento materno exclusivo por 6 meses, adoção de hábitos alimentares saudáveis, uso diário de dentífrico com flúor, interrupção de hábitos deletérios e visitas regulares ao médico-dentista para cuidados preventivos individualizados para a criança. Considera-se que a prevenção e os cuidados orais durante a primeira infância desempenham um papel crucial na preservação da saúde oral e geral, contribuindo para uma diminuição das doenças que afetam a cavidade oral.The importance of emphasizing oral health promotion in children is based not only on the intention to educate society about oral health concepts and practices but also on the prevention of diseases that can have negative repercussions on child well-being. In this context, the study of prevention and oral health care in children from 0 to 6 years old will provide an overview of preventive methods as well as the main conditions affecting the oral cavity in this age group. The present study aimed to address the importance of preventing oral diseases in childhood by investigating associated risk factors and the underlying mechanisms of their development. Additionally, methods of oral health care will be discussed to assess their positive impact on children’s lives through the adoption of health practices. The research method used was through a narrative literature review, using online search engines such as SciELO, PubMed, B-On, and Google Scholar, in Portuguese and English, for review articles, case reports, and systematic reviews. The main preventive measures adopted to ensure proper oral health throughout life include prenatal counseling and dental treatments for pregnant women, the baby’s first visit between 6 months and 1 year of age, establishing the “dental home,” exclusive breastfeeding for 6 months, adopting healthy eating habits, daily use of fluoride toothpaste, cessation of deleterious habits, and regular visits to the dentist for individualized preventive care for the child. It is considered that oral prevention and care during early childhood play a crucial role in preserving oral and overall health, contributing to a decrease in diseases affecting the oral cavity
The expression of UPF1 is regulated by a cap-independent translation initiation mechanism and a cryptic promoter within its 5’ untranslated region
Regulation of gene expression occurs at several steps, including translation initiation. Under normal circumstances, translation initiation is mainly cap-dependent; however, several proteins can initiate translation in a cap-independent way, allowing the maintenance of these proteins under conditions that reduce global protein synthesis.
hUPF1(human up-frameshift 1) plays important roles in several key cellular processes such as nonsense-mediated decay, telomere replication and homeostasis, and cell cycle progression, suggesting its expression must be tightly regulated to prevent abnormal cell proliferation. This protein is essential in the G2/M transition, a step known by a reduced overall protein synthesis. Taking these data into account, we hypothesized that UPF1 might initiate translation in a cap-independent way, allowing the cell to maintain its levels under conditions that impair cap-dependent translation initiation.
To test this hypothesis, we cloned the hUPF1 5’UTR in a dicistronic vector and transfected CC and CRC cell lines with either this construct or the control counterparts. We observed a 15- to 25-fold increase in relative luciferase activity of the UPF1 5’UTR-containing construct compared to the levels obtained from the empty counterpart in all tested cell lines, suggesting a cap-independent translation initiation. To control whether luciferase activity levels are due to a cryptic promoter within UPF1 5’UTR, we transfected cells with promoterless plasmids and observed the same result, demonstrating that UPF1 5’UTR contains a cryptic promoter. Transfecting cells with in vitro transcribed mRNAs resulted in a 2-fold increase in protein levels, suggesting that translation can occur in a cap-independent way. This is maintained under conditions of global protein synthesis inhibition. Deletional analysis of UPF1 5’UTR revealed that the first 50 nucleotides are essential for cryptic promoter and cap-independent activities.
These results provide new insights on the mechanisms that govern UPF1 expression
Analysis of the 5’ untranslated region of human UPF1 mRNA indicates both cryptic promoter and internal ribosome entry site activity
Apart from its role in nonsense-mediated mRNA decay, a mechanism that promotes rapid degradation of transcripts carrying premature translation termination codons, the human up-frameshift 1 (UPF1) DNA and RNA helicase protein plays a crucial role in telomere replication and homeostasis, and in cell cycle progression. Due to its relevance for several physiological roles, and to the fact that it is expressed during G2/M phase, in which overall protein synthesis is reduced, we hypothesized that its translation may occur via an internal ribosome entry site (IRES). IRESs can occur at the 5’ untranslated region (UTR) of transcripts and allow the direct recruitment of the ribosome to the vicinity of the main AUG, therefore bypassing the need of scanning the entire UTR.
To test this hypothesis, we cloned the human UPF1 5’UTR in the dicistronic vector p_Renilla_Firefly and transfected HeLa cells with either this construct or the control counterparts. We observed a 15- to 25-fold increase in relative luciferase activity of the UPF1 5’UTR-containing construct compared to the levels obtained from the empty counterpart, which suggests the presence of an IRES. However, these levels of luciferase activity could be due to the presence of a cryptic promoter. Hence, we transfected cells with promoterless plasmids and observed a 20-fold increase in relative luciferase activity levels. These data demonstrate that UPF1 5’UTR contains a cryptic promoter, whose activity may be masking IRES activity. To check the IRES activity alone, we have transfected cells with in vitro transcribed, capped and polyadenylated mRNAs and observed a 2-fold increase in protein levels. This is also observed in two other cell lines. Besides, UPF1 IRES activity is maintained under conditions of global protein synthesis inhibition. Deletional analysis of UPF1 5’UTR revealed that the first 50 nucleotides at the 5’ end of this region are essential for both cryptic promoter and IRES activity. These results evidence, for the first time, the existence of both a cryptic promoter and an IRES element within UPF1 5’UTR and provide new insights on the regulation of UPF1 expression in human cells
Human Argonaute 1 5’ untranslated region can mediate cap-independent translation initiation via an internal ribosome entry site
Argonaute proteins (AGOs) are essential effectors in RNA-mediated gene silencing pathways. There are eight AGO-like proteins in human cells, grouped in two families: the eIF2C/AGO subfamily and the PIWI subfamily. The eIF2C1 gene encodes AGO1, a member of the former subfamily, that is ubiquitously expressed at low to medium levels and it is highly conserved during evolution reflecting its important physiological roles. Moreover, recent studies concluded that AGO1 protein is overexpressed in colorectal cancer, relative to adjacent non-cancer tissue, without a concomitant increase in mRNA levels. These pieces of evidence lead us to suspect that high AGO1 protein levels may be due to internal ribosome entry site (IRES)-mediated translation. IRESs are structures that can mediate cap-independent translation initiation by directly recruiting ribosomes to the AUG vicinity, thus skipping the scanning of the whole 5’ untranslated region (UTR), in response to stress. To confirm this hypothesis, we transiently transfected colorectal cancer HCT116 and cervical cancer HeLa cells with an AGO1 5’UTR-containing dicistronic vector, and luciferase activity was measured by luminometry assays. Results have shown a 2-fold increase in relative luciferase activity in both cell lines, when compared to the cells transfected with the empty counterpart (P<0.05). Transfection of the corresponding promoterless plasmids ruled out the hypothesis of this fold to be due to the existence of a cryptic promoter. In addition, RT-PCR analyses of the dicistronic mRNAs confirmed that no cryptic splicing occurs. Besides, the knock-down of the eIF4E subunit induced a significant 2- to 4-fold increase in IRES activity. Taken together, these data suggest the presence of an IRES in the AGO1 5’UTR whose biological relevance is still under thorough investigation
Human UPF1: a cap-independent translation initiation mechanism and a cryptic promoter regulate its gene expression in cancer cells
Cervical (CC) and colorectal (CRC) cancers are among the leading causes of death worldwide and their development and progression is dependent on regulation of gene expression. Eukaryotic cells possess a variety of post-transcriptional mechanisms by which they regulate gene expression, namely at translation initiation level. Although in most cases it occurs via the cap-dependent mechanism, several oncogenes, growth factors or proteins involved in the regulation of programmed cell death, among others, have a different translation initiation mechanism. It involves the direct recruitment of the ribosome to the vicinity of the initiation codon without the involvement of the cap structure. This allows the maintenance of protein synthesis under several cellular stresses and promotes tumourigenesis.
Apart from its role in nonsense-mediated decay, the human up-frameshift 1 (UPF1) DNA and RNA helicase protein plays a crucial role in telomere replication and homeostasis, and in cell cycle progression. In addition, its expression levels are maintained in every phase of the cell cycle, thus indicating that its translation may occur via a cap-independent mechanism. To test this hypothesis, we cloned the human UPF1 5’UTR in a dicistronic vector and transfected CC and CRC cell lines with either this construct or the control counterparts. We observed a 15- to 25-fold increase in relative luciferase activity of the UPF1 5’UTR-containing construct compared to the levels obtained from the empty counterpart in all tested cell lines, suggesting a cap-independent translation initiation. To control whether these levels of luciferase activity could be due to the presence of a cryptic promoter, we transfected cells with promoterless plasmids and observed the same result, demonstrating that UPF1 5’UTR contains a cryptic promoter. To check the cap-independent translation activity alone, we transfected cells with in vitro transcribed, capped and polyadenylated mRNAs and observed a 2-fold increase in protein levels, which shows that translation can occur in a cap-independent way. This is maintained under conditions of global protein synthesis inhibition. Deletional analysis of UPF1 5’UTR revealed that first 50 nucleotides are essential for both cryptic promoter and cap-independent activities. These results provide new insights on the regulation of UPF1 expression in human cancer cells
O discurso acerca do feminino na educação infantil : enfrentamentos e desafios
Trabalho de Conclusão de Curso (graduação)—Universidade de Brasília, Faculdade de Educação, 2019.O presente estudo busca compreender e analisar o discurso do feminino na Educação Infantil, explanar a necessidade da igualdade entre os gêneros e a importância dessa etapa na desconstrução de estereótipos para a construção de uma sociedade que reconheça e viva a diferença, de maneira geral. O objetivo geral deste trabalho é buscar problematizar os discursos acerca do feminino, que são direcionados às meninas e aos meninos na educação infantil. Alguns dos teóricos que basearam as linhas de pensamento do presente trabalho foram Adela Turin (1995), Ana Colling (2004), Cecilia Sardenberg (1994), Claudia Vianna (2009) e Ana Alice Costa (1994). O trabalho foi realizado por meio de uma pesquisa qualitativa, com dinâmicas conversacionais com professoras e crianças, acompanhando a rotina na sala de aula de crianças de cinco a seis anos de idade, em uma escola privada, localizada no Distrito Federal, coletando discursos e frases para o enriquecimento da discussão. Percebemos que os estereótipos estão presentes de forma muito expressiva em nossa sociedade, trazidos cultural e historicamente, mas a sua desconstrução é possível e necessária. Concluímos que, no espaço da educação infantil, os estereótipos já estão presentes e devem ser abordados para que ocorra esse processo de desconstrução para que, com isso, possamos criar uma sociedade mais igualitária e justa para todos.The present study seeks to understand and analyze the image of the female in Early Childhood Education, explain the need for equality between genders and the importance of this stage in the deconstruction of stereotypes, for the growth of society, in general. The general objective of this work is to search the problematization of the speeches about the feminine that are directed to the girls and boys in the classroom. Some of the theorists who based the lines of thought of the present work were Adela Turin (1995), Ana Colling (2004), Cecilia Sardenberg (1994), Claudia Vianna (2009) and Ana Alice Costa (1994). The research was carried out through a qualitative research, with conversational dynamics with teachers and children, following the daily routine in the classroom of kids with five and six years old, in a private school, located in the Federal District, gathering speeches and phrases to enrich the discussion. We realize that stereotypes are present in a very expressive way in our society, brought culturally and historically, but the deconstruction is possible and necessary. We conclude that stereotypes in the area of early childhood education are already present and must be approached in order for this process of deconstruction to occur, so that we can create a more egalitarian and just society for all
Indicators For Evaluating Overweight And Obesity Actions In Primary Care - A Scoping Review Protocol / Indicadores Para Avaliar Acções De Excesso De Peso E Obesidade Nos Cuidados Primários - Um Protocolo De Revisão Do Âmbito
Background: The evaluation of health policies and actions allows us to measure the effectiveness of interventions and to suggest adjustments in order to achieve the desired outcome. Identifying indicators that reflect the different aspects of coping with overweight and obesity is a challenge for health evaluators, and shows the scope and relevance of the evaluative studies in the area. Aim:This article aims to present a protocol for a scoping review on the mapping of indicators used in primary care to monitor and evaluate actions for dealing with overweight and obesity. It is intended to answer the following questions: What are the indicators used to assess and monitor actions to deal with overweight and obesity in primary care? Are the indicators used able to assess and monitor the different components inherent in the recommended interventions to address overweight and obesity in primary care? Are the indicators used in line with the principles of primary care?Methods:The protocol described here was based on the recommendations of the PRISMA EXTENSION FOR SCOPING REVIEWS - PRISMA -Scr and the framework proposed by Arksey and O'Malley. Expected Results: It is hoped that the results of the scoping review can contribute to the improvement of health evaluation related to overweight and obesity in primary care. In order to disseminate the results and make it possible to reach the actors involved with overweight and obesity, the results of the scoping review will be published in a scientific magazine and presented at conferences and other relevant events
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