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BACKGROUND: Although mainly causing a respiratory syndrome, numerous neurological symptoms have been identified following of SARS-CoV-2 infection. However, how the virus affects the brain and how the mutations carried by the different variants modulate those neurological symptoms remain unclear. METHODS: We used primary human pericytes, foetal astrocytes, endothelial cells and a microglial cell line to investigate the effect of several SARS-CoV-2 variants of concern or interest on their functional activities. Cells and a 3D blood-brain barrier model were infected with the wild-type form of SARS-CoV-2, Alpha, Beta, Delta, Eta, or Omicron (BA.1) variants at various MOI. Cells and supernatant were used to evaluate cell susceptibility to the virus using a microscopic assay as well as effects of infection on (i) cell metabolic activity using a colorimetric MTS assay; (ii) viral cytopathogenicity using the xCELLigence system; (iii) extracellular glutamate concentration by fluorometric assay; and (iv) modulation of blood-brain barrier permeability. RESULTS: We demonstrate that productive infection of brain cells is SARS-CoV-2 variant dependent and that all the variants induce stress to CNS cells. The wild-type virus was cytopathic to all cell types except astrocytes, whilst Alpha and Beta variants were only cytopathic for pericytes, and the Omicron variant cytopathic for endothelial cells and pericytes. Lastly wild-type virus increases blood-brain barrier permeability and all variants, except Beta, modulate extracellular glutamate concentration, which can lead to excitotoxicity or altered neurotransmission. CONCLUSIONS: These results suggest that SARS-CoV-2 is neurotropic, with deleterious consequences for the blood-brain barrier integrity and central nervous system cells, which could underlie neurological disorders following SARS-CoV-2 infection.
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COVID-19 , SARS-CoV-2 , Humanos , Barreira Hematoencefálica , Células Endoteliais , Ácido GlutâmicoRESUMO
Progression of tuberculosis is tightly linked to a disordered immune balance, resulting in inability of the host to restrict intracellular bacterial replication and its subsequent dissemination. The immune response is mainly characterized by an orchestrated recruitment of inflammatory cells secreting cytokines. This response results from the activation of innate immunity receptors that trigger downstream intracellular signaling pathways involving adaptor proteins such as the TIR-containing adaptor protein (Tirap). In humans, resistance to tuberculosis is associated with a loss-of-function in Tirap. Here, we explore how genetic deficiency in Tirap impacts resistance to Mycobacterium tuberculosis (Mtb) infection in a mouse model and ex vivo. Interestingly, compared to wild type littermates, Tirap heterozygous mice were more resistant to Mtb infection. Upon investigation at the cellular level, we observed that mycobacteria were not able to replicate in Tirap-deficient macrophages compared to wild type counterparts. We next showed that Mtb infection induced Tirap expression which prevented phagosomal acidification and rupture. We further demonstrate that the Tirap-mediated anti-tuberculosis effect occurs through a Cish-dependent signaling pathway. Our findings provide new molecular evidence about how Mtb manipulates innate immune signaling to enable intracellular replication and survival of the pathogen, thus paving the way for host-directed approaches to treat tuberculosis.
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Mycobacterium tuberculosis , Tuberculose , Humanos , Camundongos , Animais , Receptores de Interleucina-1/genética , Receptores de Interleucina-1/metabolismo , Transdução de Sinais , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Concentração de Íons de Hidrogênio , Glicoproteínas de Membrana/metabolismoRESUMO
Patients with blood cancer continue to have a greater risk of inadequate immune responses following three COVID-19 vaccine doses and risk of severe COVID-19 disease. In the context of the CAPTURE study (NCT03226886), we report immune responses in 80 patients with blood cancer who received a fourth dose of BNT162b2. We measured neutralizing antibody titers (NAbTs) using a live virus microneutralization assay against wild-type (WT), Delta, and Omicron BA.1 and BA.2 and T cell responses against WT and Omicron BA.1 using an activation-induced marker (AIM) assay. The proportion of patients with detectable NAb titers and T cell responses after the fourth vaccine dose increased compared with that after the third vaccine dose. Patients who received B cell-depleting therapies within the 12 months before vaccination have the greatest risk of not having detectable NAbT. In addition, we report immune responses in 57 patients with breakthrough infections after vaccination.
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Vacinas contra COVID-19 , COVID-19 , Neoplasias , Humanos , Anticorpos Neutralizantes , Anticorpos Antivirais , Vacina BNT162 , Estudos Clínicos como Assunto , COVID-19/prevenção & controle , Vacinas contra COVID-19/imunologia , Imunidade , SARS-CoV-2Assuntos
Anticorpos Neutralizantes/biossíntese , Anticorpos Antivirais/biossíntese , Vacinas contra COVID-19/imunologia , COVID-19/prevenção & controle , Neoplasias Hematológicas/imunologia , Imunização Secundária , SARS-CoV-2/imunologia , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , COVID-19/complicações , COVID-19/epidemiologia , Neoplasias Hematológicas/complicações , Humanos , Imunogenicidade da Vacina , Neoplasias/complicações , Neoplasias/imunologia , Avaliação de SintomasRESUMO
The Mycobacterium tuberculosis complex (MTBC) is a group of related pathogens that cause tuberculosis (TB) in mammals. MTBC species are distinguished by their ability to sustain in distinct host populations. While Mycobacterium bovis (Mbv) sustains transmission cycles in cattle and wild animals and causes zoonotic TB, M. tuberculosis (Mtb) affects human populations and seldom causes disease in cattle. The host and pathogen determinants underlying host tropism between MTBC species are still unknown. Macrophages are the main host cell that encounters mycobacteria upon initial infection, and we hypothesised that early interactions between the macrophage and mycobacteria influence species-specific disease outcome. To identify factors that contribute to host tropism, we analysed blood-derived primary human and bovine macrophages (hMÏ or bMÏ, respectively) infected with Mbv and Mtb. We show that Mbv and Mtb reside in different cellular compartments and differentially replicate in hMÏ whereas both Mbv and Mtb efficiently replicate in bMÏ. Specifically, we show that out of the four infection combinations, only the infection of bMÏ with Mbv promoted the formation of multinucleated giant cells (MNGCs), a hallmark of tuberculous granulomas. Mechanistically, we demonstrate that both MPB70 from Mbv and extracellular vesicles released by Mbv-infected bMÏ promote macrophage multinucleation. Importantly, we extended our in vitro studies to show that granulomas from Mbv-infected but not Mtb-infected cattle contained higher numbers of MNGCs. Our findings implicate MNGC formation in the contrasting pathology between Mtb and Mbv for the bovine host and identify MPB70 from Mbv and extracellular vesicles from bMÏ as mediators of this process.
Assuntos
Interações Hospedeiro-Patógeno/fisiologia , Macrófagos/microbiologia , Mycobacterium bovis , Mycobacterium tuberculosis , Tuberculose/microbiologia , Tropismo Viral/fisiologia , Animais , Bovinos , Células Gigantes , HumanosRESUMO
The ability of Mycobacterium tuberculosis to form serpentine cords is intrinsically related to its virulence, but specifically how M. tuberculosis cording contributes to pathogenesis remains obscure. Here, we show that several M. tuberculosis clinical isolates form intracellular cords in primary human lymphatic endothelial cells (hLECs) in vitro and in the lymph nodes of patients with tuberculosis. We identified via RNA-Seq a transcriptional program that activated, in infected-hLECs, cell survival and cytosolic surveillance of pathogens pathways. Consistent with this, cytosolic access was required for intracellular M. tuberculosis cording. Mycobacteria lacking ESX-1 type VII secretion system or phthiocerol dimycocerosates expression, which failed to access the cytosol, were indeed unable to form cords within hLECs. Finally, we show that M. tuberculosis cording is a size-dependent mechanism used by the pathogen to avoid its recognition by cytosolic sensors and evade either resting or IFN-γ-induced hLEC immunity. These results explain the long-standing association between M. tuberculosis cording and virulence and how virulent mycobacteria use intracellular cording as strategy to successfully adapt and persist in the lymphatic tracts.
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Antígenos de Bactérias , Proteínas de Bactérias , Células Endoteliais , Evasão da Resposta Imune , Mycobacterium tuberculosis , Tuberculose , Fatores de Virulência , Antígenos de Bactérias/genética , Antígenos de Bactérias/imunologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Células Cultivadas , Células Endoteliais/imunologia , Células Endoteliais/microbiologia , Células Endoteliais/patologia , Humanos , Interferon gama/genética , Interferon gama/imunologia , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/imunologia , Mycobacterium tuberculosis/patogenicidade , RNA-Seq , Tuberculose/genética , Tuberculose/imunologia , Tuberculose/patologia , Fatores de Virulência/genética , Fatores de Virulência/imunologiaRESUMO
A striking and unexplained feature of granulomatous inflammation is its anatomical association with the lymphatic system. Accumulating evidence suggests that lymphatic tracks and granulomas may alter the function of each other. The formation of new lymphatics, or lymphangiogenesis, is an adaptive response to tumor formation, infection, and wound healing. Granulomas also may induce lymphangiogenesis which, through a variety of mechanisms, could contribute to disease outcomes in tuberculosis and sarcoidosis. On the other hand, alterations in lymph node function and lymphatic draining may be primary events which attenuate the risk and severity of granulomatous inflammation. This review begins with an introduction of granulomatous inflammation and the lymphatic system. A role of the lymphatic system in tuberculosis and sarcoidosis is then hypothesized. With a focus on lymphangiogenesis in these diseases, and on the potential for this process to promote dissemination, parallels are established with the well-established role of lymphangiogenesis in tumor biology.
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Inflamação/patologia , Sistema Linfático/patologia , Sarcoidose/patologia , Tuberculose/patologia , Animais , Granuloma/patologia , Humanos , Linfonodos/patologia , Linfangiogênese/fisiologia , Vasos Linfáticos/patologia , Neoplasias/patologiaRESUMO
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
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BACKGROUND: Phthiocerol dimycocerosates (PDIM), glycolipids found on the outer surface of virulent members of the Mycobacterium tuberculosis (Mtb) complex, are a major contributing factor to the pathogenesis of Mtb. Myelocytic cells, such as macrophages and dendritic cells, are the primary hosts for Mtb after infection and previous studies have shown multiple roles for PDIM in supporting Mtb in these cells. However, Mtb can infect other cell types. We previously showed that Mtb efficiently replicates in human lymphatic endothelial cells (hLECs) and that the hLEC cytosol acts as a reservoir for Mtb in humans. Here, we examined the role of PDIM in Mtb translocation to the cytosol in hLECs. RESULTS: Analysis of a Mtb mutant unable to produce PDIM showed less co-localisation of bacteria with the membrane damage marker Galectin-8 (Gal8), indicating that PDIM strongly contribute to phagosomal membrane damage. Lack of this Mtb lipid also leads to a reduction in the proportion of Mtb co-localising with markers of macroautophagic removal of intracellular bacteria (xenophagy) such as ubiquitin, p62 and NDP52. hLEC imaging with transmission electron microscopy shows that Mtb mutants lacking PDIM are much less frequently localised in the cytosol, leading to a lower intracellular burden. CONCLUSIONS: PDIM is needed for the disruption of the phagosome membrane in hLEC, helping Mtb avoid the hydrolytic phagolysosomal milieu. It facilitates the translocation of Mtb into the cytosol, and the decreased intracellular burden of Mtb lacking PDIM indicates that the cytosol is the preferred replicative niche for Mtb in these cells. We hypothesise that pharmacological targeting of PDIM synthesis in Mtb would reduce the formation of a lymphatic reservoir of Mtb in humans.
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Citosol/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Líquido Intracelular/efeitos dos fármacos , Lipídeos/toxicidade , Mycobacterium tuberculosis/efeitos dos fármacos , Citosol/metabolismo , Citosol/microbiologia , Células Endoteliais/metabolismo , Células Endoteliais/microbiologia , Humanos , Líquido Intracelular/metabolismo , Líquido Intracelular/microbiologia , Mycobacterium tuberculosis/metabolismo , Fagocitose/efeitos dos fármacos , Fagocitose/fisiologiaRESUMO
The interaction of Mycobacterium tuberculosis (Mtb) with pulmonary epithelial cells is critical for early stages of bacillus colonization and during the progression of tuberculosis. Entry of Mtb into epithelial cells has been shown to depend on F-actin polymerization, though the molecular mechanisms are still unclear. Here, we demonstrate that mycobacterial uptake into epithelial cells requires rearrangements of the actin cytoskeleton, which are regulated by ADP-ribosylation factor 1 (Arf1) and phospholipase D1 (PLD1), and is dependent on the M3 muscarinic receptor (M3R). We show that this pathway is controlled by Arf GTPase-activating protein 1 (ArfGAP1), as its silencing has an impact on actin cytoskeleton reorganization leading to uncontrolled uptake and replication of Mtb. Furthermore, we provide evidence that this pathway is critical for mycobacterial entry, while the cellular infection with other pathogens, such as Shigella flexneri and Yersinia pseudotuberculosis, is not affected. Altogether, these results reveal how cortical actin plays the role of a barrier to prevent mycobacterial entry into epithelial cells and indicate a novel role for ArfGAP1 as a restriction factor of host-pathogen interactions.
Assuntos
Citoesqueleto de Actina/metabolismo , Actinas/genética , Proteínas Ativadoras de GTPase/genética , Interações Hospedeiro-Patógeno , Mycobacterium tuberculosis/patogenicidade , Alvéolos Pulmonares/metabolismo , Células A549 , Fator 1 de Ribosilação do ADP/genética , Fator 1 de Ribosilação do ADP/metabolismo , Citoesqueleto de Actina/microbiologia , Citoesqueleto de Actina/ultraestrutura , Actinas/metabolismo , Proteínas Ativadoras de GTPase/antagonistas & inibidores , Proteínas Ativadoras de GTPase/metabolismo , Regulação da Expressão Gênica , Humanos , Mycobacterium tuberculosis/fisiologia , Fosfolipase D/genética , Fosfolipase D/metabolismo , Polimerização , Alvéolos Pulmonares/microbiologia , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Receptor Muscarínico M3/genética , Receptor Muscarínico M3/metabolismo , Shigella flexneri/fisiologia , Transdução de Sinais , Especificidade da Espécie , Yersinia pseudotuberculosis/fisiologiaRESUMO
Mycobacterium tuberculosis (Mtb), the etiological agent of human tuberculosis (TB), has plagued humans for thousands of years. TB still remains a major public health problem in our era, causing more than 4,400 deaths worldwide every day and killing more people than HIV. After inhaling Mtb-contaminated aerosols, TB primo-infection starts in the terminal lung airways, where Mtb is taken up by alveolar macrophages. Although macrophages are known as professional killers for pathogens, Mtb has adopted remarkable strategies to circumvent host defenses, building suitable conditions to survive and proliferate. Within macrophages, Mtb initially resides inside phagosomes, where its survival mostly depends on its ability to take control of phagosomal processing, through inhibition of phagolysosome biogenesis and acidification processes, and by progressively getting access to the cytosol. Bacterial access to the cytosolic space is determinant for specific immune responses and cell death programs, both required for the replication and the dissemination of Mtb. Comprehension of the molecular events governing Mtb survival within macrophages is fundamental for the improvement of vaccine-based and therapeutic strategies in order to help the host to better defend itself in the battle against the fierce invader Mtb. In this mini-review, we discuss recent research exploring how Mtb conquers and transforms the macrophage into a strategic base for its survival and dissemination as well as the associated defense strategies mounted by host.
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Pathogens have evolved a range of mechanisms to counteract host defenses, notably to survive harsh acidic conditions in phagosomes. In the case of Mycobacterium tuberculosis, it has been shown that regulation of phagosome acidification could be achieved by interfering with the retention of the V-ATPase complexes at the vacuole. Here, we present evidence that M. tuberculosis resorts to yet another strategy to control phagosomal acidification, interfering with host suppressor of cytokine signaling (SOCS) protein functions. More precisely, we show that infection of macrophages with M. tuberculosis leads to granulocyte-macrophage colony-stimulating factor (GM-CSF) secretion, inducing STAT5-mediated expression of cytokine-inducible SH2-containing protein (CISH), which selectively targets the V-ATPase catalytic subunit A for ubiquitination and degradation by the proteasome. Consistently, we show that inhibition of CISH expression leads to reduced replication of M. tuberculosis in macrophages. Our findings further broaden the molecular understanding of mechanisms deployed by bacteria to survive.
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Mycobacterium tuberculosis/patogenicidade , Fagossomos/metabolismo , Proteínas Supressoras da Sinalização de Citocina/metabolismo , Animais , Camundongos , Mycobacterium tuberculosis/metabolismo , Transdução de SinaisRESUMO
Mycolactone, a polyketide molecule produced by Mycobacterium ulcerans, is the etiological agent of Buruli ulcer. This lipid toxin is endowed with pleiotropic effects, presents cytotoxic effects at high doses, and notably plays a pivotal role in host response upon colonization by the bacillus. Most remarkably, mycolactone displays intriguing analgesic capabilities: the toxin suppresses or alleviates the pain of the skin lesions it inflicts. We demonstrated that the analgesic capability of mycolactone was not attributable to nerve damage, but instead resulted from the triggering of a cellular pathway targeting AT2 receptors (angiotensin II type 2 receptors; AT2R), and leading to potassium-dependent hyperpolarization. This demonstration paves the way to new nature-inspired analgesic protocols. In this direction, we assess here the hyperpolarizing properties of mycolactone on nociceptive neurons. We developed a dedicated medium-throughput assay based on membrane potential changes, and visualized by confocal microscopy of bis-oxonol-loaded Dorsal Root Ganglion (DRG) neurons. We demonstrate that mycolactone at non-cytotoxic doses triggers the hyperpolarization of DRG neurons through AT2R, with this action being not affected by known ligands of AT2R. This result points towards novel AT2R-dependent signaling pathways in DRG neurons underlying the analgesic effect of mycolactone, with the perspective for the development of new types of nature-inspired analgesics.
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Analgésicos/farmacologia , Toxinas Bacterianas/farmacologia , Macrolídeos/farmacologia , Neurônios/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Gânglios Espinais/citologia , Potenciais da Membrana/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/fisiologia , Receptor Tipo 2 de Angiotensina/metabolismoRESUMO
Tuberculosis (TB) is a leading infectious cause of death worldwide. The use of ethionamide (ETH), a main second line anti-TB drug, is hampered by its severe side effects. Recently discovered "booster" molecules strongly increase the ETH efficacy, opening new perspectives to improve the current clinical outcome of drug-resistant TB. To investigate the simultaneous delivery of ETH and its booster BDM41906 in the lungs, we co-encapsulated these compounds in biodegradable polymeric nanoparticles (NPs), overcoming the bottlenecks inherent to the strong tendency of ETH to crystallize and the limited water solubility of this Booster. The efficacy of the designed formulations was evaluated in TB infected macrophages using an automated confocal high-content screening platform, showing that the drugs maintained their activity after incorporation in NPs. Among tested formulations, "green" ß-cyclodextrin (pCD) based NPs displayed the best physico-chemical characteristics and were selected for in vivo studies. The NPs suspension, administered directly into mouse lungs using a Microsprayer®, was proved to be well-tolerated and led to a 3-log decrease of the pulmonary mycobacterial load after 6 administrations as compared to untreated mice. This study paves the way for a future use of pCD NPs for the pulmonary delivery of the [ETH:Booster] pair in TB chemotherapy.
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Antituberculosos/farmacologia , Quimioterapia Combinada/métodos , Etionamida/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Oxidiazóis/farmacologia , Piperidinas/farmacologia , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Pulmonar/tratamento farmacológico , Administração por Inalação , Animais , Modelos Animais de Doenças , Portadores de Fármacos , Composição de Medicamentos/métodos , Sinergismo Farmacológico , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Mycobacterium tuberculosis/crescimento & desenvolvimento , Mycobacterium tuberculosis/patogenicidade , Nanopartículas/administração & dosagem , Nanopartículas/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Células RAW 264.7 , Solubilidade , Resultado do Tratamento , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Tuberculose Resistente a Múltiplos Medicamentos/patologia , Tuberculose Pulmonar/microbiologia , Tuberculose Pulmonar/patologia , beta-Ciclodextrinas/químicaRESUMO
Tuberculosis (TB) is still a major global threat, killing more than one million persons each year. With the constant increase of Mycobacterium tuberculosis strains resistant to first- and second-line drugs, there is an urgent need for the development of new drugs to control the propagation of TB. Although screenings of small molecules on axenic M. tuberculosis cultures were successful for the identification of novel putative anti-TB drugs, new drugs in the development pipeline remains scarce. Host-directed therapy may represent an alternative for drug development against TB. Indeed, M. tuberculosis has multiple specific interactions within host phagocytes, which may be targeted by small molecules. In order to enable drug discovery strategies against microbes residing within host macrophages, we developed multiple fluorescence-based HT/CS phenotypic assays monitoring the intracellular replication of M. tuberculosis as well as its intracellular trafficking. What we propose here is a population-based, multi-parametric analysis pipeline that can be used to monitor the intracellular fate of M. tuberculosis and the dynamics of cellular events such as phagosomal maturation (acidification and permeabilization), zinc poisoning system or lipid body accumulation. Such analysis allows the quantification of biological events considering the host-pathogen interplay and may thus be derived to other intracellular pathogens. © 2017 International Society for Advancement of Cytometry.
Assuntos
Mycobacterium tuberculosis/metabolismo , Tuberculose/microbiologia , Animais , Antituberculosos/farmacologia , Bioensaio/métodos , Células Cultivadas , Descoberta de Drogas/métodos , Fluorescência , Macrófagos/metabolismo , Macrófagos/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Células RAW 264.7 , Tuberculose/tratamento farmacológicoRESUMO
Mycobacterium tuberculosis produces several bacterial effectors impacting the colonization of phagocytes. Here, we report that the putative lipoprotein LppM hinders phagocytosis by macrophages in a toll-like receptor 2-dependent manner. Moreover, recombinant LppM is able to functionally complement the phenotype of the mutant, when exogenously added during macrophage infection. LppM is also implicated in the phagosomal maturation, as a lppM deletion mutant is more easily addressed towards the acidified compartments of the macrophage than its isogenic parental strain. In addition, this mutant was affected in its ability to induce the secretion of pro-inflammatory chemokines, interferon-gamma-inducible protein-10, monocyte chemoattractant protein-1 and macrophage inflammatory protein-1α. Thus, our results describe a new mycobacterial protein involved in the early trafficking of the tubercle bacillus and its manipulation of the host immune response.