Exploring NAD(+) metabolism in host-pathogen interactions

Nicotinamide adenine dinucleotide (NAD+) is a vital molecule found in all living cells. NAD+ intracellular levels are dictated by its synthesis, using the de novo and/or salvage pathway, and through its catabolic use as co-enzyme or co-substrate. The regulation of NAD+ metabolism has proven to be an adequate drug target for several diseases, including cancer, neurodegenerative or inflammatory diseases. Increasing interest has been given to NAD+ metabolism during innate and adaptive immune responses suggesting that its modulation could also be relevant during host-pathogen interactions. While the maintenance of NAD+ homeostatic levels assures an adequate environment for host cell survival and proliferation, fluctuations in NAD+ or biosynthetic precursors bioavailability have been described during host-pathogen interactions, which will interfere with pathogen persistence or clearance. Here, we review the double-edged sword of NAD+ metabolism during host-pathogen interactions emphasizing its potential for treatment of infectious diseases.JG was supported by PD/BD/106053/2015. BV was supported by IRD (Institut de Recherche pour le Développement) institutional funding. JE was supported by a European Community’s Seventh Framework Program under grant agreement No. 602773 (Project KINDRED), an ANR grant (LEISH-APO, France) and a Partenariat Hubert Curien (PHC) (program Volubilis, MA/11/262). JE also thanks the Canada Research Chair program for his support. RS thank FCT—Foundation for Science and Technology—for their Investigator FCT Grant (IF/00021/2014)info:eu-repo/semantics/publishedVersio

The impact of IL-10 dynamic modulation on host immune response against visceral leishmaniasis

Leishmaniasis is a vector-borne disease caused by protozoan parasites from the genus Leishmania. The most severe form of disease is visceral leishmaniasis (VL), which is fatal if left untreated. It has been demonstrated that interleukin (IL)-10, is associated with disease progression and susceptibility. In this work, we took advantage of a transgenic mouse model that expresses high levels of IL-10 upon zinc sulfate administration (pMT-10). We addressed the role of IL-10 during the initial stages of L. donovani infection by analyzing the parasite burden in the spleen and liver of the infected pMT-10 and WT mice as well as the histopathological alterations upon IL-10 induction. Furthermore, the profile of cytokines expressed by T cells was assessed. Our results demonstrate that an increase in IL-10 production has an impact early but not later after infection. This specific temporal role for IL-10-mediated susceptibility to VL is of interest.Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) (NORTE-01-0145-FEDER-000013) and the Fundação para a Ciência e Tecnologia (FCT) (contracts SFRH/BD/120127/2016 to IM, PD/BDE/127830/2016 to CF, SFRH/BD/120371/2016 to AMB, IF/01147/2013 to RDO, IF/01390/2014 to ET, IF/00735/2014 to AC, SFRH/BPD/96176/2013 to CC and IF/00021/2014 to RS), and Infect-Era (project INLEISH). JE also thanks the Canada Research Chair program for financial assistanceinfo:eu-repo/semantics/publishedVersio

Estudo da interação entre imunidade e metabolismo durante infeção por Leishmania

Tese de Doutoramento em Ciências da SaúdeAs escolhas metabólicas condicionam a função das células imunes e o decorrer da infeção. Os agentes patogénicos evoluíram com os hospedeiros, desenvolvendo estratégias para aumentar a sobrevivência através do bloqueio das capacidades microbicidas do hospedeiro: através do sequestro do metabolismo do hospedeiro e controlo da polarização de células imunes. Observou-se que na ausência do fator HIF-1a ocorria um aumento da lipogénese em células mieloides infetadas com Leishmania donovani, através do eixo BNIP3/mTOR/SREBP-1c, que levou a um aumento de suscetibilidade a estes parasitas. A perda de função decorrente do polimorfismo no gene HIF1A recapitulou as observações anteriores, uma vez que macrófagos de indivíduos com o genótipo CT/TT acumularam mais lípidos e revelaram-se mais suscetíveis. Esta suscetibilidade foi revertida através do bloqueio da lipogénese, realçando a importância da acumulação de lípidos para a infeção. A susceptibilidade de ratinhos mHIF-1a-/- cronicamente infetados deriva da exaustão de linfócitos T. Observou-se um aumento de expressão do recetor TIM-3 em linfócitos T no baço de ratinhos mHIF-1a-/- infetados, assim como perda da produção de citoquinas efetoras. Observou-se, igualmente, um aumento do número de células mielóides produtoras de IL-10, sugerindo que um ambiente imunossupressor poderá contribuir para a exaustão de células T. Estes resultados sugerem que abordagens imunoterapêuticas poderão revitalizar os linfócitos T durante a cronicidade e contribuir para a eliminação do parasita. Uma vez a IL-10 foi associada a imunossupressão, decidiu-se estudar o impacto desta citoquina em diferentes etapas da infeção. Induziu-se a expressão de IL-10 na etapa inicial e tardia de infeção por L. donovani, usando ratinhos pMT-10. Observou-se que a expressão de IL-10 nas etapas iniciais culminaram num aumento da carga parasitária no baço e fígado, assim como na perda de linfócitos T multifuncionais e diminuição do ratio IFN-g/IL-10, indicativo de menor proteção contra a infeção. Finalmente, foi proposto dissecar o papel do tecido adiposo branco como reservatório de L. donovani. Estes resultados demonstram que os parasitas são capazes de acumular no tecido adiposo branco, especialmente em ratinhos com excesso de peso, sugerindo um novo reservatório que pode alterar a resposta do hospedeiro às terapias antiparasíticas. Este trabalho realça a importância das redes imunometabólicas durante a infeção, enfatizando a complexidade das interações patogénio-hospedeiro. Estudando esta interface dinâmica, demonstrou-se como este conhecimento pode ajudar a desenvolver novas terapias.It is now accepted that metabolic choices condition immune cell function and the outcome of infection. Pathogens have evolved closely with their hosts, thus developing strategies to optimize and enhance their survival by hindering host’s microbicidal capacity. Pathogens actively hijack host metabolism to fulfill their bioenergetic and biosynthetic needs and control immune cell polarization. We showed that genetic deficiency of HIF-1a increased lipogenesis in Leishmania donovani-infected myeloid cells through the BNIP3/mTOR/SREBP-1c axis, which contributed to increased susceptibility, both in vitro and in vivo. A loss-of-function SNP in the human HIF1A gene recapitulated previous findings, as macrophages from individuals with the CT/TT genotype accumulated more lipids and were more susceptible to infection. This susceptibility was reversed through blockade of lipogenesis, highlighting the importance of lipid accumulation during infection. During chronicity, myeloid-restricted HIF-1a-/- mice (mHIF-1a-/-) susceptibility associated with T cell exhaustion. We found increased expression of TIM-3 in T cells from the spleen of infected mHIF- 1a-/- mice, as well as loss of effector cytokine production. Higher levels of IL-10-producing myeloid cells were also found, suggesting an immunosuppressive environment that may contribute to T cell exhaustion. This suggests that immunotherapeutic approaches may reinvigorate T cells during chronic infection and contribute to pathogen clearance. As IL-10 has been vastly associated to immunosuppression, we sought to study its impact in different stages of Leishmania infection. We induced IL-10 overexpression both at early and late stages of L. donovani infection, using the pMT- 10 mouse model. IL-10 overexpression early after infection increased parasite burden in both the spleen and liver and led to loss of multifunctional CD4 T cells and decreased IFN-g/IL-10 ratios, indicative of lower protection against infection. Finally, we proposed to dissect the role of white adipose tissue as a reservoir during leishmaniasis, as we showed that lipid-rich environments are permissive niches. Our data demonstrates that these parasites are capable of accumulating in the white adipose tissue. This was particularly evident in overweighted mice, suggesting the existence of a new, undiscovered reservoir that can alter host response to antileishmanial therapies. The work here presented highlights the importance of the immunometabolic network during Leishmania infection, while emphasizing the complexity inherent to host-pathogen interactions. By tackling different cornerstones of this dynamic interface, we demonstrated how this knowledge can be translated into the development of innovative antileishmanial therapies.The work presented in this thesis was performed in the Life and Health Sciences Research Institute (ICVS), Minho University. Financial support was provided by grants from Foundation of Science and Technology (FCT) through the Individual Fellowship SFRH/BD/120127/2016, Infect-Era (project INLEISH), the European Society of Clinical Microbiology and Infectious Diseases (ESCMID Research Grant 2019) and the ICVS Scientific Microscopy Platform, member of the national infrastructure PPBI - Portuguese Platform of Bioimaging (PPBI-POCI-01-0145-FEDER-022122; by National funds, through the Foundation for Science and Technology (FCT) - project UIDB/50026/2020 and UIDP/50026/2020; and by the projects NORTE-01-0145-FEDER-000013 and NORTE-01-0145-FEDER-000023, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF)

Predictors of adult spelling in an orthography of intermediate depth

What is the hallmark of a good speller? Spelling is a critical component in learning to become literate, but how it works in literate adults remains poorly explored. We examined word and pseudoword spelling in 214 adults in relation to general cognitive abilities, vocabulary, reading history, reading performance, phonological processing and rapid automatized naming. We conducted hierarchical multiple regression analyses to uncover predictors of spelling performance and compared a subsample of good and poor spellers to identify patterns of cognitive and language abilities associated with high vs. low spelling ability. In the regression model under test, which progressed from general cognitive and language abilities to specific reading-related skills, the most important predictor for word spelling was vocabulary, and for pseudoword spelling phonological processing (phoneme deletion). The model explained 20% of word spelling, and 8% of pseudoword spelling, variance. Good spellers outperformed poor spellers in reading connected text and pseudowords, and in phonological processing; poor spellers typically had a history of reading difficulties but similar levels of cognitive ability, word reading and RAN performance. Overall, our findings indicate that adult spelling relies more strongly on word knowledge than on reading proficiency and that, as in literacy acquisition, good phonology-related abilities are a hallmark of proficient adult spellers.info:eu-repo/semantics/publishedVersio

Obesity effects on muscular activity during lifting and lowering tasks

"Published online: 15 Jun 2019"Obesity is an emerging health problem and its incidence has been increasing throughout the workforce. In industrial workstations, vertical handling tasks (VHT), including lifting and lowering, are very common and can cause a significant muscular overload for the involved workers. During these tasks, muscular activity may be considerably affected by workers' body conditions. This study aims to analyze and compare the muscular activity in subjects with different obesity levels, using surface electromyography (EMG), during predefined VHT. Six different VHT (combining 5, 10 and 15-kg loads with two task styles) were performed. EMG data normalization was based on the percentage of maximum contraction during each task (MCT%). The results show that obesity influences the MCT%, which in turn increases the muscular effort during VHT. The current investigation demonstrates that obesity is a relevant musculoskeletal risk factor regarding VHT. The engineering analysis and design implications of this work can thus be perceived.This work has been supported by FCT – Fundação para a Ciência e Tecnologia [Project Scope UID/CEC/00319/2019

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved