Publications by authors named "Margarida Saraiva"

64 Publications

Infection Up-Regulates Sialyl Lewis X Expression in the Lung Epithelium.

Microorganisms 2021 Jan 4;9(1). Epub 2021 Jan 4.

i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.

Glycans display increasingly recognized roles in pathological contexts, however, their impact in the host-pathogen interplay in many infectious diseases remains largely unknown. This is the case for tuberculosis (TB), one of the ten most fatal diseases worldwide, caused by infection of the bacteria . We have recently reported that perturbing the core-2 -glycans biosynthetic pathway increases the host susceptibility to infection, by disrupting the neutrophil homeostasis and enhancing lung pathology. In the present study, we show an increased expression of the sialylated glycan structure Sialyl-Lewis X (SLeX) in the lung epithelium upon infection. This increase in SLeX glycan epitope is accompanied by an altered lung tissue transcriptomic signature, with up-regulation of genes codifying enzymes that are involved in the SLeX core-2 -glycans biosynthetic pathway. This study provides novel insights into previously unappreciated molecular mechanisms involving glycosylation, which modulate the host response to infection, possibly contributing to shape TB disease outcome.
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http://dx.doi.org/10.3390/microorganisms9010099DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7823657PMC
January 2021

Type I IFN exacerbates disease in tuberculosis-susceptible mice by inducing neutrophil-mediated lung inflammation and NETosis.

Nat Commun 2020 11 4;11(1):5566. Epub 2020 Nov 4.

Laboratory of Immunoregulation and Infection, The Francis Crick Institute, London, NW1 1AT, UK.

Tuberculosis (TB) is a leading cause of mortality due to infectious disease, but the factors determining disease progression are unclear. Transcriptional signatures associated with type I IFN signalling and neutrophilic inflammation were shown to correlate with disease severity in mouse models of TB. Here we show that similar transcriptional signatures correlate with increased bacterial loads and exacerbate pathology during Mycobacterium tuberculosis infection upon GM-CSF blockade. Loss of GM-CSF signalling or genetic susceptibility to TB (C3HeB/FeJ mice) result in type I IFN-induced neutrophil extracellular trap (NET) formation that promotes bacterial growth and promotes disease severity. Consistently, NETs are present in necrotic lung lesions of TB patients responding poorly to antibiotic therapy, supporting the role of NETs in a late stage of TB pathogenesis. Our findings reveal an important cytokine-based innate immune effector network with a central role in determining the outcome of M. tuberculosis infection.
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http://dx.doi.org/10.1038/s41467-020-19412-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7643080PMC
November 2020

The Portuguese Society for Immunology (SPI): history and mission.

Eur J Immunol 2020 07;50(7):918-920

Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.

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http://dx.doi.org/10.1002/eji.202070075DOI Listing
July 2020

The bone marrow hematopoietic niche and its adaptation to infection.

Semin Cell Dev Biol 2020 Jun 15. Epub 2020 Jun 15.

i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal; Departamento de Biologia Molecular, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal. Electronic address:

Hematopoiesis is responsible for the formation of all blood cells from hematopoietic stem cells (HSC) in the bone marrow (BM). It is a highly regulated process, in order to adapt its cellular output to changing body requirements. Specific microenvironmental conditions within the BM must exist in order to maintain HSC pluripotency and self-renewal, as well as to ensure appropriate differentiation of progenitor cells towards each hematopoietic lineage. Those conditions were coined "the hematopoietic niche" and their identity in terms of cell types, location and soluble molecular components has been the subject of intense research in the last decades. Infections are one of the environmental challenges to which hematopoiesis must respond, to feed the immune system with functional cell components and compensate for cellular losses. However, how infections impact the bone marrow hematopoietic niche(s) remains elusive and most of the mechanisms involved are still largely unknown. Here, we review the most recent advances on our knowledge on the hematopoietic niche composition and regulation during homeostasis and also on how the niche responds to infectious stress.
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http://dx.doi.org/10.1016/j.semcdb.2020.05.014DOI Listing
June 2020

Botulism disguised as parotitis.

IDCases 2020 25;21:e00839. Epub 2020 May 25.

Infectious Diseases Department, Centro Hospitalar Universitário de São João, Portugal.

Botulism is an acute toxin-mediated neuroparalytic syndrome caused by some species. It typically presents itself as an acute symmetric descending paralysis of cranial and peripheral nerves, which can potentially evolve to respiratory failure and death. We report a case of botulism diagnosed in a patient presenting with a parotitis probably due to xerostomia, even though he had already sought medical assistance for blurred vision and dysphagia. The neurological symptoms resolved without administration of antitoxin and botulism diagnosis was confirmed with identification of both toxins B and F in patient's serum. We aim to illustrate the need for a high clinical suspicion for the diagnosis of botulism and to report an atypical case of botulism with the production of toxins B and F, the latter being of rare occurrence.
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http://dx.doi.org/10.1016/j.idcr.2020.e00839DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7264047PMC
May 2020

Characterization of Multidrug-Resistant Isolates of Serovars Heidelberg and Minnesota from Fresh Poultry Meat Imported to Portugal.

Microb Drug Resist 2021 Jan 27;27(1):87-98. Epub 2020 May 27.

Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health (INSA), Lisbon, Portugal.

serovars Heidelberg and Minnesota frequently display several genetic mobile elements making them potential spreaders of resistance genes. Here, we phenotypically determined the antibiotic resistance profile and subsequently performed whole-genome sequencing on 36 isolates recovered from samples of fresh poultry meat, within the Portuguese Official Inspection Plan for Imported Foodstuffs. Several isolates of both serovars showed high genetic relatedness either with isolates from raw poultry meat imported to the Netherlands from Brazil or with isolates from samples from the broiler production chain in Brazil. The multidrug-resistant (MDR) character was common to the vast majority (94.4%) of isolates from both serovars, and several isolates carried the plasmid IncA/C2 containing the β-lactamase gene and IncX1 containing a type IV secretion system. These results somehow mirror the scenario observed in the Netherlands, showing the introduction, through fresh imported poultry meat in compliance with European legislation, of MDR serovars Heidelberg and Minnesota in Europe, with the potential spread of resistance markers. These data suggest the need to revise the hygiene criteria for foodstuffs monitoring before its placement on the market, with the determination of the resistome being an invaluable contribute to limit the dissemination of resistance markers.
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http://dx.doi.org/10.1089/mdr.2019.0384DOI Listing
January 2021

Mycobacterium tuberculosis associated with severe tuberculosis evades cytosolic surveillance systems and modulates IL-1β production.

Nat Commun 2020 04 23;11(1):1949. Epub 2020 Apr 23.

i3S-Instituto de Investigação e Inovação em Saúde, University of Porto, Porto, Portugal.

Genetic diversity of Mycobacterium tuberculosis affects immune responses and clinical outcomes of tuberculosis (TB). However, how bacterial diversity orchestrates immune responses to direct distinct TB severities is unknown. Here we study 681 patients with pulmonary TB and show that M. tuberculosis isolates from cases with mild disease consistently induce robust cytokine responses in macrophages across multiple donors. By contrast, bacteria from patients with severe TB do not do so. Secretion of IL-1β is a good surrogate of the differences observed, and thus to classify strains as probable drivers of different TB severities. Furthermore, we demonstrate that M. tuberculosis isolates that induce low levels of IL-1β production can evade macrophage cytosolic surveillance systems, including cGAS and the inflammasome. Isolates exhibiting this evasion strategy carry candidate mutations, generating sigA recognition boxes or affecting components of the ESX-1 secretion system. Therefore, we provide evidence that M. tuberculosis strains manipulate host-pathogen interactions to drive variable TB severities.
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http://dx.doi.org/10.1038/s41467-020-15832-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7181847PMC
April 2020

Mouse transcriptome reveals potential signatures of protection and pathogenesis in human tuberculosis.

Nat Immunol 2020 04 16;21(4):464-476. Epub 2020 Mar 16.

Laboratory of Immunoregulation and Infection, The Francis Crick Institute, London, UK.

Although mouse infection models have been extensively used to study the host response to Mycobacterium tuberculosis, their validity in revealing determinants of human tuberculosis (TB) resistance and disease progression has been heavily debated. Here, we show that the modular transcriptional signature in the blood of susceptible mice infected with a clinical isolate of M. tuberculosis resembles that of active human TB disease, with dominance of a type I interferon response and neutrophil activation and recruitment, together with a loss in B lymphocyte, natural killer and T cell effector responses. In addition, resistant but not susceptible strains of mice show increased lung B cell, natural killer and T cell effector responses in the lung upon infection. Notably, the blood signature of active disease shared by mice and humans is also evident in latent TB progressors before diagnosis, suggesting that these responses both predict and contribute to the pathogenesis of progressive M. tuberculosis infection.
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http://dx.doi.org/10.1038/s41590-020-0610-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7116040PMC
April 2020

Deficiency in the glycosyltransferase Gcnt1 increases susceptibility to tuberculosis through a mechanism involving neutrophils.

Mucosal Immunol 2020 09 13;13(5):836-848. Epub 2020 Mar 13.

i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.

Modulation of immunity and disease by glycans is increasingly recognized. However, how host glycosylation shapes and is shaped by tuberculosis remains poorly understood. We show that deficiency in the glucosaminyl (N-acetyl) transferase 1 (Gcnt1), a key enzyme for core-2 O-glycans biosynthesis, drives susceptibility to Mycobacterium tuberculosis infection. The increased susceptibility of Gcnt1 deficient mice was characterized by extensive lung immune pathology, mechanistically related to neutrophils. Uninfected Gcnt1 deficient mice presented bone marrow, blood and lung neutrophilia, which further increased with infection. Blood neutrophilia required Gcnt1 deficiency in the hematopoietic compartment, relating with enhanced granulopoiesis, but normal cellular egress from the bone marrow. Interestingly, for the blood neutrophilia to translate into susceptibility to M. tuberculosis infection, Gnct1 deficiency in the stroma was also necessary. Complete Gcnt1 deficiency associated with increased lung expression of the neutrophil chemoattractant CXCL2. Lastly, we demonstrate that the transcript levels of various glycosyltransferase-encoding genes were altered in whole blood of active tuberculosis patients and that sialyl Lewis x, a glycan widely present in human neutrophils, was detected in the lung of tuberculosis patients. Our findings reveal a previously unappreciated link between Gcnt1, neutrophilia and susceptibility to M. tuberculosis infection, uncovering new players balancing the immune response in tuberculosis.
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http://dx.doi.org/10.1038/s41385-020-0277-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7434595PMC
September 2020

Biology and therapeutic potential of interleukin-10.

J Exp Med 2020 01;217(1)

Laboratory of Immunoregulation and Infection, The Francis Crick Institute, London, UK.

The cytokine IL-10 is a key anti-inflammatory mediator ensuring protection of a host from over-exuberant responses to pathogens and microbiota, while playing important roles in other settings as sterile wound healing, autoimmunity, cancer, and homeostasis. Here we discuss our current understanding of the regulation of IL-10 production and of the molecular pathways associated with IL-10 responses. In addition to IL-10's classic inhibitory effects on myeloid cells, we also describe the nonclassic roles attributed to this pleiotropic cytokine, including how IL-10 regulates basic processes of neural and adipose cells and how it promotes CD8 T cell activation, as well as epithelial repair. We further discuss its therapeutic potential in the context of different diseases and the outstanding questions that may help develop an effective application of IL-10 in diverse clinical settings.
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http://dx.doi.org/10.1084/jem.20190418DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7037253PMC
January 2020

Myeloid HIF-1α regulates pulmonary inflammation during experimental Mycobacterium tuberculosis infection.

Immunology 2020 01 10;159(1):121-129. Epub 2019 Nov 10.

Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.

The transcription factor hypoxia-inducible factor-1 alpha (HIF-1α) is a key regulator of the response and function of myeloid cells in hypoxic and inflammatory microenvironments. To define the role of HIF-1α in tuberculosis, the progression of aerosol Mycobacterium tuberculosis infection was analysed in mice deficient in HIF-1α in the myeloid lineage (mHIF-1α ). We show that myeloid HIF-1α is not required for the containment of the infection, as both wild-type (WT) and mHIF-1α mice mounted normal Th1 responses and maintained control of bacterial growth throughout infection. However, during chronic infection mHIF-1α mice developed extensive lymphocytic inflammatory involvement of the interstitial lung tissue and died earlier than WT mice. These data support the hypothesis that HIF-1α activity coordinates the response of myeloid cells during M. tuberculosis infection to prevent excessive leucocyte recruitment and immunopathological consequences to the host.
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http://dx.doi.org/10.1111/imm.13131DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6904637PMC
January 2020

Experimental Evidence for Limited Virulence of .

Front Microbiol 2019 10;10:2102. Epub 2019 Sep 10.

i3S - Instituto de Investigação e Inovação em Saúde, Porto, Portugal.

Tuberculosis remains a public health problem and a main cause of death to humans. Both and cause tuberculosis. In contrast to , which is geographically spread, is restricted to West Africa. Differences have also been found in the growth rate and type of disease caused by , globally suggesting an attenuation of this bacteria. In this study, we used the mouse model of infection to follow the dynamics of infection in terms of bacterial burdens and tissue pathology, as well as the immune response triggered. Our findings support a lower virulence of as compared to , including in mice lacking IFN-γ, a major protective cytokine in tuberculosis. Furthermore, the lung immune response triggered by infection in wild-type animals was characterized by a discrete influx of leukocytes and a modest transcriptional upregulation of inflammatory mediators. Our findings contribute to elucidate the pathogenesis of , supporting the hypothesis that this is an attenuated member of the tuberculosis-causing bacteria. Understanding the biology of and how it interacts with the host to establish infection will have implications for our knowledge of TB and for the development of novel and better tools to control this devastating disease.
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http://dx.doi.org/10.3389/fmicb.2019.02102DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6746983PMC
September 2019

Downregulated Cathepsin E expression in bone marrow-derived macrophages from the pre-clinical familial amyloid polyneuropathy model.

Amyloid 2019;26(sup1):63-64

a I3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto , Porto , Portugal.

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http://dx.doi.org/10.1080/13506129.2019.1585342DOI Listing
January 2020

Paradigm changing evidence that alter tuberculosis perception and detection: Focus on latency.

Infect Genet Evol 2019 08 18;72:78-85. Epub 2018 Dec 18.

i3S - Instituto de Investigação e Inovação em Saúde, Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal. Electronic address:

Tuberculosis remains a devastating disease to Mankind, ranking as the ninth cause of death worldwide. Eliminating tuberculosis as proven much more difficult than once anticipated. In addition to the delay in diagnosis and drug resistance problems that compromise the efficacy of treatment, the enormous reservoir of latently infected individuals continuously feeds the epidemics. However, targeting latency with prophylactic antibiotic administration is not possible at the populational level. Together, these issues call for a better understanding of latency, as well as for a more precise identification of individuals at high risk of reactivation. For this, recent paradigm changing evidence need to be taken into account, most notably, the existence of a tuberculosis spectrum; the genetic diversity of both humans and tuberculosis-causing bacteria; and the changes in the human population that interfere with tuberculosis. Here we discuss latency in the light of these variables and how that understanding can move forward tuberculosis research and elimination.
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http://dx.doi.org/10.1016/j.meegid.2018.12.019DOI Listing
August 2019

MDSCs in infectious diseases: regulation, roles, and readjustment.

Cancer Immunol Immunother 2019 Apr 19;68(4):673-685. Epub 2018 Dec 19.

Nuclear Receptor Group, Department of Cell Biology, Physiology and Immunology, School of Biology, University of Barcelona, Av. Diagonal, 643, 3rd floor, 08028, Barcelona, Spain.

Many pathogens, ranging from viruses to multicellular parasites, promote expansion of MDSCs, which are myeloid cells that exhibit immunosuppressive features. The roles of MDSCs in infection depend on the class and virulence mechanisms of the pathogen, the stage of the disease, and the pathology associated with the infection. This work compiles evidence supported by functional assays on the roles of different subsets of MDSCs in acute and chronic infections, including pathogen-associated malignancies, and discusses strategies to modulate MDSC dynamics to benefit the host.
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http://dx.doi.org/10.1007/s00262-018-2277-yDOI Listing
April 2019

A Nonribosomal Peptide Synthase Gene Driving Virulence in Mycobacterium tuberculosis.

mSphere 2018 10 31;3(5). Epub 2018 Oct 31.

i3S-Instituto de Investigação e Inovação em Saúde, Porto, Portugal

Nonribosomal peptide synthases produce short peptides in a manner that is distinct from classical mRNA-dependent ribosome-mediated translation. The genome harbors a nonribosomal peptide synthase gene, , which is part of a gene cluster proposed to be involved in the biosynthesis of isonitrile lipopeptides. Orthologous clusters are found in other slow-growing pathogenic mycobacteria and actinomycetes. To probe the role of the gene in infection, we generated an deletion mutant in H37Rv and tested its virulence in immunocompetent (C57BL/6) mice. The mutant strain displayed lower initial growth rates in the lungs and a defective dissemination to the spleens of infected mice. Mice infected with the mutant strain also survived for twice as long as those infected with wild-type and, remarkably, showed subdued pathology, despite similar bacterial loads at later stages of infection. The differences in the course of infection between wild-type and mutant strains were accompanied by distinct dynamics of the immune response. Most strikingly, the mutant was highly attenuated in immunodeficient (SCID-, recombination activating 2 [RAG2]-, and gamma interferon [IFN-γ]-deficient) mice, suggesting that macrophages control the mutant more efficiently than they control the wild-type strain. However, in the presence of IFN-γ, both strains were equally controlled. We propose that the gene and its associated cluster are drivers of virulence during the early stages of infection. Over 10 million people developed tuberculosis (TB) in 2016, and over 1.8 million individuals succumbed to the disease. These numbers make TB the ninth leading cause of death worldwide and the leading cause from a single infectious agent. Therefore, finding novel therapeutic targets in , the pathogen that causes most cases of human TB, is critical. In this study, we reveal a novel virulence factor in , the gene. The lack of highly attenuates the course of infection in the mouse model, which is particularly relevant in immune-deficient hosts. This is very relevant as TB is particularly incident in immune-suppressed individuals, such as HIV patients.
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http://dx.doi.org/10.1128/mSphere.00352-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6211224PMC
October 2018

L-Threonine Supplementation During Colitis Onset Delays Disease Recovery.

Front Physiol 2018 5;9:1247. Epub 2018 Sep 5.

Life and Health Sciences Research Institute, School of Health Sciences, University of Minho, Braga, Portugal.

Dietary nutrients have emerged as potential therapeutic adjuncts for inflammatory bowel disease (IBD) given their impact on intestinal homeostasis through the modulation of immune response, gut microbiota composition and epithelial barrier stability. Several nutrients have already been associated with a protective phenotype. Yet, there is a lack of knowledge toward the most promising ones as well as the most adequate phase of action. To unveil the most prominent therapy candidates we characterized the colon metabolic profile during colitis development. We have observed a twofold decrease in threonine levels in mice subjected to DSS-induced colitis. We then assessed the effect of threonine supplementation in the beginning of the inflammatory process (DSS + Thr) or when inflammation is already established (DSS + Thr D8). Colitis progression was similar between the treated groups and control colitic mice, yet threonine had a surprisingly detrimental effect when administered in the beginning of the disease, with mice displaying a delayed recovery when compared to control mice and mice supplemented with threonine after day 8. Although no major changes were found in their metabolic profile, DSS + Thr mice displayed altered expression in mucin-encoding genes, as well as in goblet cell counts, unveiling an impaired ability to produce mucus. Moreover, IL-22 secretion was decreased in DSS + Thr mice when compared to DSS + Thr D8 mice. Overall, these results suggest that supplementation with threonine during colitis induction impact goblet cell number and delays the recovery period. This reinforces the importance of a deeper understanding regarding threonine supplementation in IBD.
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http://dx.doi.org/10.3389/fphys.2018.01247DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6134202PMC
September 2018

How to measure the immunosuppressive activity of MDSC: assays, problems and potential solutions.

Cancer Immunol Immunother 2019 Apr 21;68(4):631-644. Epub 2018 May 21.

Research Division, Department of Otorhinolaryngology, West German Cancer Center, University Hospital Essen, Hufelandstrasse 55, 45122, Essen, Germany.

Myeloid-derived suppressor cells (MDSC) are a heterogeneous group of mononuclear and polymorphonuclear myeloid cells, which are present at very low numbers in healthy subjects, but can expand substantially under disease conditions. Depending on disease type and stage, MDSC comprise varying amounts of immature and mature differentiation stages of myeloid cells. Validated unique phenotypic markers for MDSC are still lacking. Therefore, the functional analysis of these cells is of central importance for their identification and characterization. Various disease-promoting and immunosuppressive functions of MDSC are reported in the literature. Among those, the capacity to modulate the activity of T cells is by far the most often used and best-established read-out system. In this review, we critically evaluate the assays available for the functional analysis of human and murine MDSC under in vitro and in vivo conditions. We also discuss critical issues and controls associated with those assays. We aim at providing suggestions and recommendations useful for the contemporary biological characterization of MDSC.
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http://dx.doi.org/10.1007/s00262-018-2170-8DOI Listing
April 2019

Chemokines cooperate with TNF to provide protective anti-viral immunity and to enhance inflammation.

Nat Commun 2018 05 3;9(1):1790. Epub 2018 May 3.

Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Cantoblanco, Madrid, 28049, Spain.

The role of cytokines and chemokines in anti-viral defense has been demonstrated, but their relative contribution to protective anti-viral responses in vivo is not fully understood. Cytokine response modifier D (CrmD) is a secreted receptor for TNF and lymphotoxin containing the smallpox virus-encoded chemokine receptor (SECRET) domain and is expressed by ectromelia virus, the causative agent of the smallpox-like disease mousepox. Here we show that CrmD is an essential virulence factor that controls natural killer cell activation and allows progression of fatal mousepox, and demonstrate that both SECRET and TNF binding domains are required for full CrmD activity. Vaccination with recombinant CrmD protects animals from lethal mousepox. These results indicate that a specific set of chemokines enhance the inflammatory and protective anti-viral responses mediated by TNF and lymphotoxin, and illustrate how viruses optimize anti-TNF strategies with the addition of a chemokine binding domain as soluble decoy receptors.
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http://dx.doi.org/10.1038/s41467-018-04098-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5934441PMC
May 2018

The Dynamics of Interleukin-10-Afforded Protection during Dextran Sulfate Sodium-Induced Colitis.

Front Immunol 2018 1;9:400. Epub 2018 Mar 1.

i3S - Instituto de Investigação e Inovação em Saúde, Porto, Portugal.

Inflammatory bowel disease encompasses a group of chronic-inflammatory conditions of the colon and small intestine. These conditions are characterized by exacerbated inflammation of the organ that greatly affects the quality of life of patients. Molecular mechanisms counteracting this hyperinflammatory status of the gut offer strategies for therapeutic intervention. Among these regulatory molecules is the anti-inflammatory cytokine interleukin (IL)-10, as shown in mice and humans. Indeed, IL-10 signaling, particularly in macrophages, is essential for intestinal homeostasis. We sought to investigate the temporal profile of IL-10-mediated protection during chemical colitis and which were the underlying mechanisms. Using a novel mouse model of inducible IL-10 overexpression (pMT-10), described here, we show that mice preconditioned with IL-10 for 8 days before dextran sulfate sodium (DSS) administration developed a milder colitic phenotype. In IL-10-induced colitic mice, Ly6C cells isolated from the showed a decreased inflammatory profile. Because our mouse model leads to transcription of the IL-10 transgene in the bone marrow and elevated seric IL-10 concentration, we investigated whether IL-10 could imprint immune cells in a long-lasting way, thus conferring sustained protection to colitis. We show that this was not the case, as IL-10-afforded protection was only observed if IL-10 induction immediately preceded DSS-mediated colitis. Thus, despite the protection afforded by IL-10 in colitis, novel strategies are required, specifically to achieve long-lasting protection.
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http://dx.doi.org/10.3389/fimmu.2018.00400DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5837963PMC
May 2019

The Host-Pathogen-Extrinsic Factors in Tuberculosis: Modulating Inflammation and Clinical Outcomes.

Front Immunol 2017 9;8:1948. Epub 2018 Jan 9.

i3S-Instituto de Investigação e Inovação em Saúde, University of Porto, Porto, Portugal.

The already enormous burden caused by tuberculosis (TB) will be further aggravated by the association of this disease with modern epidemics, as human immunodeficiency virus and diabetes. Furthermore, the increasingly aging population and the wider use of suppressive immune therapies hold the potential to enhance the incidence of TB. New preventive and therapeutic strategies based on recent advances on our understanding of TB are thus needed. In particular, understanding the intricate network of events modulating inflammation in TB will help to build more effective vaccines and host-directed therapies to stop TB. This review integrates the impact of host, pathogen, and extrinsic factors on inflammation and the almost scientifically unexplored complexity emerging from the interactions between these three factors. We highlight the exciting data showing a contribution of this for the clinical outcome of TB and the need of incorporating it when developing novel strategies to rewire the immune response in TB.
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http://dx.doi.org/10.3389/fimmu.2017.01948DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5767228PMC
January 2018

Imported poultry meat as a source of extended-spectrum cephalosporin-resistant CMY-2-producing Salmonella Heidelberg and Salmonella Minnesota in the European Union, 2014-2015.

Int J Antimicrob Agents 2018 Jan 14;51(1):151-154. Epub 2017 Sep 14.

UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal; Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal. Electronic address:

Extended-spectrum cephalosporin (ESC)-resistant Salmonella have been described at a low level in the EU, nevertheless the increasing importation of poultry meat could be an important source of epidemic strains carrying ESC resistance genes. This study evaluated ESC resistance and its genetic platform among Salmonella isolates from poultry meat products imported into Portugal as well as clonal relatedness of the isolates. All Salmonella isolates recovered from samples of fresh meat destined for import into the EU in the scope of Portuguese official border control (2014-2015) were studied. Antibiotic susceptibility and β-lactamase production was determined by disk diffusion/microdilution. Molecular studies included detection of genes encoding acquired AmpC and extended-spectrum β-lactamases, plasmid-mediated quinolone resistance and other antibiotic resistance genes by PCR/sequencing, and clonality by MLST and XbaI-PFGE. Plasmid characterisation was assessed by conjugation assays, replicon typing (PCR-PBRT/pMLST) and hybridisation experiments (I-CeuI/S1-PFGE nuclease). Isolates belonged to Salmonella Heidelberg (n = 6; ST15/eBG26) and Salmonella Minnesota (n = 1; ST548/eBG77) and presented multidrug-resistant profiles, including to ESCs and/or fluoroquinolones. All but one carried bla, located on two epidemic plasmids, IncA/C (ST2, n = 5) or transferable IncI1 (ST12, n = 1). Salmonella Heidelberg was associated with five PFGE types, including one similar to an American epidemic clone. This study reveals imported poultry products as a source of uncommon and/or invasive ESC-resistant Salmonella strains in the EU. The increase of clinically relevant poultry-related serotypes in Europe must be taken into account in the current monitoring of antibiotic resistance trends and in re-evaluation of food regulations.
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http://dx.doi.org/10.1016/j.ijantimicag.2017.09.006DOI Listing
January 2018

Experimental study of tuberculosis: From animal models to complex cell systems and organoids.

PLoS Pathog 2017 Aug 17;13(8):e1006421. Epub 2017 Aug 17.

i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.

Tuberculosis (TB) is a devastating disease to mankind that has killed more people than any other infectious disease. Despite many efforts and successes from the scientific and health communities, the prospect of TB elimination remains distant. On the one hand, sustainable public health programs with affordable and broad implementation of anti-TB measures are needed. On the other hand, achieving TB elimination requires critical advances in three areas: vaccination, diagnosis, and treatment. It is also well accepted that succeeding in advancing these areas requires a deeper knowledge of host-pathogen interactions during infection, and for that, better experimental models are needed. Here, we review the potential and limitations of different experimental approaches used in TB research, focusing on animal and human-based cell culture models. We highlight the most recent advances in developing in vitro 3D models and introduce the potential of lung organoids as a new tool to study Mycobacterium tuberculosis infection.
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http://dx.doi.org/10.1371/journal.ppat.1006421DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5560521PMC
August 2017

Interferon-β regulates the production of IL-10 by toll-like receptor-activated microglia.

Glia 2017 09 15;65(9):1439-1451. Epub 2017 Jun 15.

i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.

Pattern recognition receptors, such as toll-like receptors (TLRs), perceive tissue alterations and initiate local innate immune responses. Microglia, the resident macrophages of the brain, encode TLRs which primary role is to protect the tissue integrity. However, deregulated activation of TLRs in microglia may lead to chronic neurodegeneration. This double role of microglial responses is often reported in immune-driven neurologic diseases, as in multiple sclerosis (MS). Consequently, strategies to manipulate microglia inflammatory responses may help to ameliorate disease progression. In this context, the anti-inflammatory cytokine interleukin (IL)-10 appears as an attractive target. In this study, we investigated how activation of microglia by TLRs with distinct roles in MS impacts on IL-10 production. We found that activation of TLR2, TLR4, and TLR9 induced the production of IL-10 to a greater extent than activation of TLR3. This was surprising as both TLR3 and IL-10 play protective roles in animal models of MS. Interestingly, combination of TLR3 triggering with the other TLRs, enhanced IL-10 through the modulation of its transcription, via interferon (IFN)-β, but independently of IL-27. Thus, in addition to the modulation of inflammatory responses of the periphery described for the axis TLR3/IFN-β, we now report a direct modulation of microglial responses. We further show that the presence of IFN-γ in the microenvironment abrogated the modulation of IL-10 by TLR3, whereas that of IL-17 had no effect. Considering the therapeutic application of IFN-β in MS, our study bears important implications for the understanding of the cytokine network regulating microglia responses in this setting.
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http://dx.doi.org/10.1002/glia.23172DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7165667PMC
September 2017

Differential expression of Cathepsin E in transthyretin amyloidosis: from neuropathology to the immune system.

J Neuroinflammation 2017 06 6;14(1):115. Epub 2017 Jun 6.

i3S - Instituto de Investigação e Inovação em Saúde da Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.

Background: Increasing evidence supports a key role for inflammation in the neurodegenerative process of familial amyloidotic polyneuropathy (FAP). While there seems to be an overactivation of the neuronal interleukin-1 signaling pathway, the immune response is apparently compromised in FAP. Accordingly, little immune cell infiltration is observed around pre-fibrillar or fibrillar amyloid deposits, with the underlying mechanism for this phenomenon remaining poorly understood. Cathepsin E (CtsE) is an important intermediate for antigen presentation and chemotaxis, but its role in the pathogenesis of FAP disease remains unknown.

Methods: In this study, we used both mouse primary macrophages and in vivo studies based on transgenic models of FAP and human samples to characterize CtsE expression in different physiological systems.

Results: We show that CtsE is critically decreased in bone marrow-derived macrophages from a FAP mouse model, possibly contributing for cell function impairment. Compromised levels of CtsE were also found in injured nerves of transgenic mice and, most importantly, in naïve peripheral nerves, sensory ganglia, murine stomach, and sural nerve biopsies derived from FAP patients. Expression of CtsE in tissues was associated with transthyretin (TTR) deposition and differentially regulated accordingly with the physiological system under study. Preventing deposition with a TTR small interfering RNA rescued CtsE in the peripheral nervous system (PNS). In contrast, the expression of CtsE increased in splenic cells (mainly monocytes) or peritoneal macrophages, indicating a differential macrophage phenotype.

Conclusion: Altogether, our data highlights the potential of CtsE as a novel FAP biomarker and a possible modulator for innate immune cell chemotaxis to the disease most affected tissues-the peripheral nerve and the gastrointestinal tract.
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http://dx.doi.org/10.1186/s12974-017-0891-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5460450PMC
June 2017

Balancing the immune response in the brain: IL-10 and its regulation.

J Neuroinflammation 2016 11 24;13(1):297. Epub 2016 Nov 24.

i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.

Background: The inflammatory response is critical to fight insults, such as pathogen invasion or tissue damage, but if not resolved often becomes detrimental to the host. A growing body of evidence places non-resolved inflammation at the core of various pathologies, from cancer to neurodegenerative diseases. It is therefore not surprising that the immune system has evolved several regulatory mechanisms to achieve maximum protection in the absence of pathology.

Main Body: The production of the anti-inflammatory cytokine interleukin (IL)-10 is one of the most important mechanisms evolved by many immune cells to counteract damage driven by excessive inflammation. Innate immune cells of the central nervous system, notably microglia, are no exception and produce IL-10 downstream of pattern recognition receptors activation. However, whereas the molecular mechanisms regulating IL-10 expression by innate and acquired immune cells of the periphery have been extensively addressed, our knowledge on the modulation of IL-10 expression by central nervous cells is much scattered. This review addresses the current understanding on the molecular mechanisms regulating IL-10 expression by innate immune cells of the brain and the implications of IL-10 modulation in neurodegenerative disorders.

Conclusion: The regulation of IL-10 production by central nervous cells remains a challenging field. Answering the many remaining outstanding questions will contribute to the design of targeted approaches aiming at controlling deleterious inflammation in the brain.
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http://dx.doi.org/10.1186/s12974-016-0763-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5121946PMC
November 2016

Type I IFN Inhibits Alternative Macrophage Activation during Mycobacterium tuberculosis Infection and Leads to Enhanced Protection in the Absence of IFN-γ Signaling.

J Immunol 2016 12 14;197(12):4714-4726. Epub 2016 Nov 14.

Microbiology and Infection Research Domain, Life and Health Sciences Research Institute, School of Health Sciences, University of Minho, and Life and Health Sciences Research Institute/3B's PT Government Associate Laboratory, 4710 Braga/Guimarães, Portugal.

Tuberculosis causes ∼1.5 million deaths every year, thus remaining a leading cause of death from infectious diseases in the world. A growing body of evidence demonstrates that type I IFN plays a detrimental role in tuberculosis pathogenesis, likely by interfering with IFN-γ-dependent immunity. In this article, we reveal a novel mechanism by which type I IFN may confer protection against Mycobacterium tuberculosis infection in the absence of IFN-γ signaling. We show that production of type I IFN by M. tuberculosis-infected macrophages induced NO synthase 2 and inhibited arginase 1 gene expression. In vivo, absence of both type I and type II IFN receptors led to strikingly increased levels of arginase 1 gene expression and protein activity in infected lungs, characteristic of alternatively activated macrophages. This correlated with increased lung bacterial burden and pathology and decreased survival compared with mice deficient in either receptor. Increased expression of other genes associated with alternatively activated macrophages, as well as increased expression of Th2-associated cytokines and decreased TNF expression, were also observed. Thus, in the absence of IFN-γ signaling, type I IFN suppressed the switching of macrophages from a more protective classically activated phenotype to a more permissive alternatively activated phenotype. Together, our data support a model in which suppression of alternative macrophage activation by type I IFN during M. tuberculosis infection, in the absence of IFN-γ signaling, contributes to host protection.
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http://dx.doi.org/10.4049/jimmunol.1600584DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5133670PMC
December 2016

Mycobacterium tuberculosis lineage 4 comprises globally distributed and geographically restricted sublineages.

Nat Genet 2016 12 31;48(12):1535-1543. Epub 2016 Oct 31.

Swiss Tropical and Public Health Institute, Basel, Switzerland.

Generalist and specialist species differ in the breadth of their ecological niches. Little is known about the niche width of obligate human pathogens. Here we analyzed a global collection of Mycobacterium tuberculosis lineage 4 clinical isolates, the most geographically widespread cause of human tuberculosis. We show that lineage 4 comprises globally distributed and geographically restricted sublineages, suggesting a distinction between generalists and specialists. Population genomic analyses showed that, whereas the majority of human T cell epitopes were conserved in all sublineages, the proportion of variable epitopes was higher in generalists. Our data further support a European origin for the most common generalist sublineage. Hence, the global success of lineage 4 reflects distinct strategies adopted by different sublineages and the influence of human migration.
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http://dx.doi.org/10.1038/ng.3704DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5238942PMC
December 2016