Identification of novel genes for glucose metabolism based upon expression pattern in human islets and effect on insulin secretion and glycemia

Normal glucose homeostasis is characterized by appropriate insulin secretion and low HbA1c. Gene expression signatures associated with these two phenotypes could be essential for islet function and pathophysiology of type 2 diabetes (T2D). Herein, we employed a novel approach to identify candidate genes involved in T2D by correlating islet microarray gene expression data (78 donors) with insulin secretion and HbA1c level. The expression of 649 genes (P < 0.05) was correlated with insulin secretion and HbA1c. Of them, five genes (GLR1A, PPP1R1A, PLCDXD3, FAM105A and ENO2) correlated positively with insulin secretion/negatively with HbA1c and one gene (GNG5) correlated negatively with insulin secretion/positively with HbA1c were followed up. The five positively correlated genes have lower expression levels in diabetic islets, whereas GNG5 expression is higher. Exposure of human islets to high glucose for 24 h resulted in up-regulation of GNG5 and PPP1R1A expression, whereas the expression of ENO2 and GLRA1 was down-regulated. No effect was seen on the expression of FAM105A and PLCXD3. siRNA silencing in INS-1 832/13 cells showed reduction in insulin secretion for PPP1R1A, PLXCD3, ENO2, FAM105A and GNG5 but not GLRA1. Although no SNP in these gene loci passed the genome-wide significance for association with T2D in DIAGRAM+ database, four SNPs influenced gene expression in cis in human islets. In conclusion, we identified and confirmed PPP1R1A, FAM105A, ENO2, PLCDX3 and GNG5 as potential regulators of islet function. We provide a list of candidate genes as a resource for exploring their role in the pathogenesis of T2

A Variant of GJD2, Encoding for Connexin 36, Alters the Function of Insulin Producing β-Cells.

Signalling through gap junctions contributes to control insulin secretion and, thus, blood glucose levels. Gap junctions of the insulin-producing β-cells are made of connexin 36 (Cx36), which is encoded by the GJD2 gene. Cx36-null mice feature alterations mimicking those observed in type 2 diabetes (T2D). GJD2 is also expressed in neurons, which share a number of common features with pancreatic β-cells. Given that a synonymous exonic single nucleotide polymorphism of human Cx36 (SNP rs3743123) associates with altered function of central neurons in a subset of epileptic patients, we investigated whether this SNP also caused alterations of β-cell function. Transfection of rs3743123 cDNA in connexin-lacking HeLa cells resulted in altered formation of gap junction plaques and cell coupling, as compared to those induced by wild type (WT) GJD2 cDNA. Transgenic mice expressing the very same cDNAs under an insulin promoter revealed that SNP rs3743123 expression consistently lead to a post-natal reduction of islet Cx36 levels and β-cell survival, resulting in hyperglycemia in selected lines. These changes were not observed in sex- and age-matched controls expressing WT hCx36. The variant GJD2 only marginally associated to heterogeneous populations of diabetic patients. The data document that a silent polymorphism of GJD2 is associated with altered β-cell function, presumably contributing to T2D pathogenesis

Xanthine analogues and adipose tissue metabolism

Obesity has been increasing in the last decades and is one of the most prolific health concern worldwide. Methylxanthines, such as caffeine (1,3,7-trimethylxanthine), theophylline (1,3-dimethylxanthine), and theobromine (3,7-dimethylxanthine), have demonstrated potential anti-obesity properties. These natural compounds are widely distributed in the human diet, especially food products such as coffee, tea, and chocolate. In fact, caffeine is known to modulate glucose and fatty acid metabolism and its consumption seems to be inversely associated with body weight increase. Based on methylxanthines chemical structure, several xanthine analogues have been synthetized. We hypothesized that one of those compounds, 8-(3-phenylpropyl)-1,3,7-triethylxanthine, may have a promising anti-obesity potential. Our study aims to characterize the modulation conferred by 8-(3-phenylpropyl)-1,3,7-triethylxanthine in the metabolic and oxidative profile of adipocytes in order to evaluate its potential as a pharmacological option to address obesity and its complications. For this purpose, the anti-obesogenic potential of 8-(3-phenylpropyl)-1,3,7-triethylxanthine was evaluated in mouse preadipocyte cell line 3T3-L1, using synthetic caffeine for comparative purposes. Cells were cultured in the presence of increasing concentrations of caffeine or 8-(3-phenylpropyl)-1,3,7-triethylxanthine (0.1, 1, 10 and 100 µM) and the cytotoxic profile was accessed spectrophotometrically by reduction of tetrazolium salt (MTT) and quantification of released lactate dehydrogenase (LDH). The metabolites in culture medium were identified and quantified by proton nuclear magnetic resonance (1H-NMR) and cells were collected for analysis of the oxidative profile. Our results show that 8-(3-phenylpropyl)-1,3,7-triethylxanthine presented no cytotoxicity at all studied concentrations. When compared with caffeine, 8-(3-phenylpropyl)-1,3,7-triethylxanthine significantly increased glucose, pyruvate, and glutamine consumption, and lactate, alanine, and acetate production. These findings illustrate that 8-(3-phenylpropyl)-1,3,7-triethylxanthine has a high potential to act as a metabolic modulator, even when compared with caffeine. Additionally, 8-(3-phenylpropyl)-1,3,7-triethylxanthine promoted an antioxidant environment, decreasing protein oxidation, and protecting against oxidative stress-induced damage. Thus, 8-(3-phenylpropyl)-1,3,7-triethylxanthine appears as a promising candidate for new and safe anti-obesity drug design.A obesidade tem aumentado nas últimas décadas e é um dos problemas de saúde mais preocupantes a nível mundial. As metilxantinas, como é o caso da cafeína (1,3,7-trimetilxantina), teofilina (1,3-dimetilxantina) e teobromina (3,7-dimetilxantina), demonstraram propriedades anti-obesogénicas bastante promissoras. Estes compostos naturais encontram-se bastante difundidos na dieta humana, nomeadamente no café, no chá e no chocolate. De entre estes fitoquímicos, a cafeína é descrita como moduladora do metabolismo da glucose e ácidos gordos, assim como o seu consumo aparenta ser inversamente proporcional ao aumento de peso corporal. Com base na estrutura química das metilxantinas, vários compostos análogos têm sido sintetizados. Foi colocada a hipótese de que um desses compostos, a 8-(3-fenilpropil)-1,3,7-trietilxantina, poderia apresentar um potencial anti-obesogénico bastante elevado. Deste modo, o nosso projeto visou avaliar os efeitos desta nova molécula no perfil metabólico e oxidativo de adipócitos, com o objetivo de avaliar o seu potencial como opção farmacológica para o tratamento da obesidade e suas complicações. Para este fim, foi utilizada como modelo in vitro a linha celular de pré-adipócitos de rato 3T3-L1 e a cafeína, de origem sintética, para fins comparativos. As células foram incubadas na presença de concentrações crescentes de cafeína e 8-(3-fenilpropil)-1,3,7-trietilxantina (0.1, 1, 10 e 100 µM) e o perfil citotóxico de ambos os compostos foi avaliado espectrofotometricamente pela redução do sal de tetrazólio (MTT) e quantificação de lactato desidrogenase (LDH) libertada. Os metabolitos presentes no meio de cultura foram identificados e quantificados recorrendo à ressonância magnética nuclear de protão (1H-NMR) e as células foram recolhidas para a caracterização do perfil oxidativo. Os nossos resultados demonstram que a 8-(3-fenilpropil)-1,3,7-trietilxantina não induziu citotoxicidade em nenhuma das concentrações estudadas. Comparativamente à cafeína, este composto aumentou significativamente o consumo de glucose, piruvato e glutamina, assim como a produção de lactato, alanina e acetato. Estes resultados ilustram o elevado potencial da 8-(3-fenilpropil)-1,3,7-trietilxantina como modulador metabólico, mesmo quando comparado com a cafeína. Adicionalmente, a 8-(3-fenilpropil)-1,3,7-trietilxantina promoveu um efeito antioxidante, diminuindo os níveis de oxidação proteica e protegendo contra os danos causados pelo stress oxidativo. Em suma, a 8-(3-fenilpropil)-1,3,7-trietilxantina apresenta-se como um ótimo candidato para o design de fármacos anti-obesidade seguros e inovadores

Sports media landscape: Investigating parasocial interactions, behaviours and the impact of sport absence due to lockdown

Sports popularity is undeniable, being one of human’s main leisure activities. Its evolution does not go unnoticed, with eSports figuring as the latest upgrade, which has been generating much controversy, with some categorizing it as just an activity while others defend the competitive gaming as a proper sport. Disputes aside, eSports are here to stay, with an on-going growth all over the world, presenting disruptive events and engaging its audience, mainly, in new media platforms. Therefore, this dissertation will review the sports evolution panorama, incorporating the role of eSports in Portugal, and consequently, how digital evolution leveraged new habits of media consumption. With that in mind, parasocial interactions topics were reviewed and related-data was analysed, being clear that in both types of platforms, enjoyment, attachment and social interaction seem to positively influence the user experience. Lastly, the experience in sports environment came under scrutiny, embedding the recent SARSCOV2 pandemic impact in the research, trying to elaborate on the main behaviours and emotions felt by sports-enthusiast population. To do all that, primary research was conducted where respondents were asked to selfevaluate themselves regarding their experience while watching sports in both Traditional and Digital platforms. One of the main conclusions drawn from this research indicated that Digital platforms are predilect for eSports enthusiasts. On the other side, conventional sports fans still prefer Traditional media, however, the discrepancy between platforms preference is less notorious. It also became clear that sports absence was much noted, with people urging to get back to live events.A popularidade do desporto é inegável, sendo considerado uma das principais atividades de lazer para o ser humano. A sua evolução não passa despercebida, com os eSports em destaque, no momento, o que tem vindo a gerar controvérsia, com investigadores categorizando-os como apenas uma atividade, enquanto outros defendem-nos, afirmando tratar-se de um desporto propriamente dito. Disputas à parte, os eSports vieram para ficar, experienciando um crescimento global contínuo, apresentando eventos disruptivos e atraindo o público, principalmente, em plataformas digitais. Portanto, esta dissertação analisará o panorama da evolução do desporto, centrando-se nos eSports em Portugal e, consequentemente, perceber como a evolução digital potenciou novos hábitos de consumo de media. Com isso em mente, o papel das interações parassociais foi escrutinado, e pode-se concluir que em ambos os tipos de plataformas, tanto a satisfação, a ligação e interação social influenciam positivamente a experiência do espectador. Finalmente, também a experiência em contexto desportivo foi averiguada, incorporando o recente impacto provocado pela pandemia de SARS-COV2, numa tentativa de aprofundar os principais comportamentos e emoções demonstradas pelos adeptos de desporto. Consequentemente, foi realizada uma pesquisa primária onde os entrevistados puderam fazer uma autoavaliação, tendo em conta a experiência pessoal de assistir a desporto, tanto em plataformas tradicionais como digitais. Uma das principais conclusões desta pesquisa indicou que as plataformas digitais são as prediletas, por larga margem, para os entusiastas de eSports. Contrariamente, os fãs de desporto convencional, preferem plataformas tradicionais, porém, a discrepância entre as preferências de plataforma é menos notória. Ficou ainda claro que a ausência de desporto foi sentida pelo público, principalmente as experiências ao vivo

TCF7L2 is a master regulator of insulin production and processing

Genome-wide association studies have revealed >60 loci associated with type 2 diabetes (T2D), but the underlying causal variants and functional mechanisms remain largely elusive. Although variants in TCF7L2 confer the strongest risk of T2D among common variants by presumed effects on islet function, the molecular mechanisms are not yet well understood. Using RNA-sequencing, we have identified a TCF7L2-regulated transcriptional network responsible for its effect on insulin secretion in rodent and human pancreatic islets. ISL1 is a primary target of TCF7L2 and regulates proinsulin production and processing via MAFA, PDX1, NKX6.1, PCSK1, PCSK2 and SLC30A8, thereby providing evidence for a coordinated regulation of insulin production and processing. The risk T-allele of rs7903146 was associated with increased TCF7L2 expression, and decreased insulin content and secretion. Using gene expression profiles of 66 human pancreatic islets donors', we also show that the identified TCF7L2-ISL1 transcriptional network is regulated in a genotype-dependent manner. Taken together, these results demonstrate that not only synthesis of proinsulin is regulated by TCF7L2 but also processing and possibly clearance of proinsulin and insulin. These multiple targets in key pathways may explain why TCF7L2 has emerged as the gene showing one of the strongest associations with T2

Classe de gestão industrial e desempenho competitivo

Dissertação sobre Competitividade da Indústria de Fundição de Metais Ferrosos elaborada para a obtenção do grau de Mestrado no ISCTE, Lisboa, em 2004

Using data envelopment analysis to assess the efficiency of portuguese post offices and postal distribution centers

The Portuguese Post Offices have suffered, since their inception in 1520, profound changes in their structure and in the services provided to the population. Anyone who visits today the company CTT Correios de Portugal, SA, whether visiting a post office, a postal distribution center or a post treatment center will certainly be surprised not only with all the technology that supports internal operations, but also with the professionalism and proactive attitude of the employees of this company. All this evolution perceived by customers is the result of five centuries of history. The aim of this study is to explore the potential of Data Envelopment Analysis (DEA) to assess the efficiency of the post offices and postal distribution centers (PDCs) in the south of Portugal. To this effect, we collected data from 84 post offices and 42 PDCs. Our results show significant differences among efficiency scores in both groups and emphasize the importance of identifying efficient units. These efficient units can serve as benchmarks for learning, revealing the type of structures and processes that can be applied in other units in order to make them efficient and sustainable. Our results also show the utility of DEA as a tool to support decision-making in this company, as this technique can assist managers in the identification of the units that have the greatest potential to improve their performance. Furthermore, the fact that DEA allows the decomposition of efficiency in two components (pure technical efficiency and scale efficiency) is very useful in order to identify the type of restructuring that can be most efficacious in each unit. Lastly, a preliminary analysis of the impact of seasonality in the efficiency of the units revealed that this can be one of the factors that contribute to explaining variations in performance in some of the units. This result suggests that, in order to remain efficient, some units may need to adjust their capacity according to the seasonOs correios de Portugal têm sofrido, desde o seu início em 1520, profundas alterações quer organizacionais quer nos serviços que prestam à população. Quem visita hoje em dia a empresa CTT Correios de Portugal, S.A., quer seja uma Loja, um Centro de Distribuição Postal ou um Centro de Tratamento, fica certamente surpreendido, não só com toda a tecnologia que auxilia as operações internas, como também com o profissionalismo e atitude proactiva dos colaboradores desta empresa. Toda esta evolução que transparece para os clientes é o reflexo de cinco séculos de história. Este estudo tem como objetivo principal explorar o potencial do Data Envelopment Analysis (DEA) para avaliar a eficiência das Lojas e dos Centros de Distribuição Postal (CDPs) a operar no sul de Portugal. Para o efeito, foram recolhidos dados de 84 lojas e 42 CDPs. Os resultados obtidos revelam diferenças significativas na eficiência das unidades de ambos os grupos e demonstram a importância de identificar unidades eficientes, as quais podem definir boas práticas a aplicar nas outras unidades a fim de as tornar eficientes e sustentáveis. Os resultados alcançados também revelam a utilidade do DEA como instrumento de apoio aos decisores desta empresa, uma vez que ajuda a analisar quais as unidades onde deve existir um maior enfoque para a melhoria da performance. Para além disso, o facto de esta técnica permitir decompor a eficiência em várias componentes (eficiência técnica pura e eficiência de escala) permite perceber qual o tipo de restruturação que deve ser implementada em cada unidade para melhorar a sua performance. Por fim, com base numa análise preliminar ao impacto da sazonalidade na eficiência das unidades dos CTT, foi possível concluir que, nalguns casos, este pode ser também um dos fatores que contribuem para explicar a variação nos níveis de eficiência, alertando para a necessidade de ajustar a capacidade de algumas unidades em função da estação.Universidade do Algarve^bFaculdade de Economi

Copy number variation in the bovine genome

<p>Abstract</p> <p>Background</p> <p>Copy number variations (CNVs), which represent a significant source of genetic diversity in mammals, have been shown to be associated with phenotypes of clinical relevance and to be causative of disease. Notwithstanding, little is known about the extent to which CNV contributes to genetic variation in cattle.</p> <p>Results</p> <p>We designed and used a set of NimbleGen CGH arrays that tile across the assayable portion of the cattle genome with approximately 6.3 million probes, at a median probe spacing of 301 bp. This study reports the highest resolution map of copy number variation in the cattle genome, with 304 CNV regions (CNVRs) being identified among the genomes of 20 bovine samples from 4 dairy and beef breeds. The CNVRs identified covered 0.68% (22 Mb) of the genome, and ranged in size from 1.7 to 2,031 kb (median size 16.7 kb). About 20% of the CNVs co-localized with segmental duplications, while 30% encompass genes, of which the majority is involved in environmental response. About 10% of the human orthologous of these genes are associated with human disease susceptibility and, hence, may have important phenotypic consequences.</p> <p>Conclusions</p> <p>Together, this analysis provides a useful resource for assessment of the impact of CNVs regarding variation in bovine health and production traits.</p