scholarly journals Peptidylarginine Deiminase inhibition abolishes the production of large extracellular vesicles fromGiardia intestinalis, affecting host-pathogen interactions by hindering adhesion to host cells

2019 ◽  
Author(s):  
Bruno Gavinho ◽  
Izadora Volpato Rossi ◽  
Ingrid Evans-Osses ◽  
Sigrun Lange ◽  
Marcel Ivan Ramirez
Keyword(s):  
Extracellular Vesicles ◽  
Mammalian Cells ◽  
Deep Understanding ◽  
Arginine Deiminase ◽  
Host Cells ◽  
Peptidylarginine Deiminase ◽  
Host Pathogen Interactions ◽  
Host Pathogen ◽  
Pad Inhibitor

AbstractGiardia intestinalisis an anaerobic protozoan that is an important etiologic agent of inflammation-driven diarrhea worldwide. Although self-limiting, a deep understanding of the factors involved in the pathogenicity that produces the disruption of the intestinal barrier remains unknown. There is evidence that under diverse conditions, the parasite is capable of shedding extracellular vesicles (EVs) which could modulate the physiopathology of giardiasis. Here we describe new insights ofG. intestinalisEV production, revealing its capacity to shed two different enriched EV populations (large and small extracellular vesicles) and identified a relevant adhesion function associated only with the larger population. Our work also aimed at assessing the influences of two recently identified inhibitors of EV release in mammalian cells, namely peptidylarginine deiminase (PAD) inhibitor and cannabidiol (CBD), on EV release fromGiardiaand their putative effects on host-pathogen interactions. PAD-inhibitor Cl-amidine and CBD were both able to effectively reduce EV shedding, the PAD-inhibitor specifically affecting the release of large extracellular vesicles and interfering within vitrohost-pathogen interactions. The strong efficacy of the PAD-inhibitor onGiardiaEV release indicates a phylogenetically conserved pathway of PAD-mediated EV release, most likely affecting theGiardiaarginine deiminase (GiADI) homolog of mammalian PADs. While there is still much to learn aboutG. intestinalisinteraction with its host, our results suggest that large and small EVs may be differently involved in protozoa communication, and that EV-inhibitor treatment may be a novel strategy for recurrent giardiasis treatment.

scholarly journals cDNA Microarray Analysis of Host-Pathogen Interactions in a Porcine In Vitro Model for Toxoplasma gondii Infection

2006 ◽  
Vol 74 (7) ◽  
pp. 4254-4265 ◽  
Author(s):  
Margaret Okomo-Adhiambo ◽  
Craig Beattie ◽  
Anette Rink
Keyword(s):  
Toxoplasma Gondii ◽  
Cdna Microarray ◽  
Host Cells ◽  
Host Pathogen Interactions ◽  
Nutrient Metabolism ◽  
Expression Ratio ◽  
Reverse Transcription Pcr ◽  
Host Pathogen ◽  
Toxoplasma Gondii Infection

ABSTRACT Toxoplasma gondii induces the expression of proinflammatory cytokines, reorganizes organelles, scavenges nutrients, and inhibits apoptosis in infected host cells. We used a cDNA microarray of 420 annotated porcine expressed sequence tags to analyze the molecular basis of these changes at eight time points over a 72-hour period in porcine kidney epithelial (PK13) cells infected with T. gondii. A total of 401 genes with Cy3 and Cy5 spot intensities of ≥500 were selected for analysis, of which 263 (65.6%) were induced ≥2-fold (expression ratio, ≥2.0; P ≤ 0.05 [t test]) over at least one time point and 48 (12%) were significantly down-regulated. At least 12 functional categories of genes were modulated (up- or down-regulated) by T. gondii. The majority of induced genes were clustered as transcription, signal transduction, host immune response, nutrient metabolism, and apoptosis related. The expression of selected genes altered by T. gondii was validated by quantitative real-time reverse transcription-PCR. These results suggest that significant changes in gene expression occur in response to T. gondii infection in PK13 cells, facilitating further analysis of host-pathogen interactions in toxoplasmosis in a secondary host.

scholarly journals Distinct Roles of Candida albicans-Specific Genes in Host-Pathogen Interactions

2014 ◽  
Vol 13 (8) ◽  
pp. 977-989 ◽  
Author(s):  
Duncan Wilson ◽  
François L. Mayer ◽  
Pedro Miramón ◽  
Francesco Citiulo ◽  
Silvia Slesiona ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Host Cells ◽  
Transcriptional Analysis ◽  
Phenotypic Characterization ◽  
Host Pathogen Interactions ◽  
Pathogenic Potential ◽  
Hyphal Branching ◽  
Content Type ◽  
Host Pathogen

ABSTRACTHuman fungal pathogens are distributed throughout their kingdom, suggesting that pathogenic potential evolved independently.Candida albicansis the most virulent member of the CUG clade of yeasts and a common cause of both superficial and invasive infections. We therefore hypothesized thatC. albicanspossesses distinct pathogenicity mechanisms.In silicogenome subtraction and comparative transcriptional analysis identified a total of 65C.albicans-specificgenes (ASGs) expressed during infection. Phenotypic characterization of six ASG-null mutants demonstrated that these genes are dispensable forin vitrogrowth but play defined roles in host-pathogen interactions. Based on these analyses, we investigated two ASGs in greater detail. An orf19.6688Δ mutant was found to be fully virulent in a mouse model of disseminated candidiasis and to induce higher levels of the proinflammatory cytokine interleukin-1β (IL-1β) following incubation with murine macrophages. Apga16Δ mutant, on the other hand, exhibited attenuated virulence. Moreover, we provide evidence that secondary filamentation events (multiple hyphae emerging from a mother cell and hyphal branching) contribute to pathogenicity:PGA16deletion did not influence primary hypha formation or extension following contact with epithelial cells; however, multiple hyphae and hyphal branching were strongly reduced. Significantly, these hyphae failed to damage host cells as effectively as the multiple hypha structures formed by wild-typeC. albicanscells. Together, our data show that species-specific genes of a eukaryotic pathogen can play important roles in pathogenicity.

scholarly journals Lipoproteins Are Responsible for the Pro-Inflammatory Property of Staphylococcus aureus Extracellular Vesicles

2021 ◽  
Vol 22 (13) ◽  
pp. 7099
Author(s):  
Pradeep Kumar Kopparapu ◽  
Meghshree Deshmukh ◽  
Zhicheng Hu ◽  
Majd Mohammad ◽  
Marco Maugeri ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Inflammatory Responses ◽  
Surface Proteins ◽  
Host Cells ◽  
Immune Stimulation ◽  
Domains Of Life ◽  
Major Surface ◽  
Staphylococcal Aureus

Staphylococcal aureus (S. aureus), a Gram-positive bacteria, is known to cause various infections. Extracellular vesicles (EVs) are a heterogeneous array of membranous structures secreted by cells from all three domains of life, i.e., eukaryotes, bacteria, and archaea. Bacterial EVs are implied to be involved in both bacteria–bacteria and bacteria–host interactions during infections. It is still unclear how S. aureus EVs interact with host cells and induce inflammatory responses. In this study, EVs were isolated from S. aureus and mutant strains deficient in either prelipoprotein lipidation (Δlgt) or major surface proteins (ΔsrtAB). Their immunostimulatory capacities were assessed both in vitro and in vivo. We found that S. aureus EVs induced pro-inflammatory responses both in vitro and in vivo. However, this activity was dependent on lipidated lipoproteins (Lpp), since EVs isolated from the Δlgt showed no stimulation. On the other hand, EVs isolated from the ΔsrtAB mutant showed full immune stimulation, indicating the cell wall anchoring of surface proteins did not play a role in immune stimulation. The immune stimulation of S. aureus EVs was mediated mainly by monocytes/macrophages and was TLR2 dependent. In this study, we demonstrated that not only free Lpp but also EV-imbedded Lpp had high pro-inflammatory activity.

scholarly journals Neurotrophin Receptor TrkC Is an Entry Receptor for Trypanosoma cruzi in Neural, Glial, and Epithelial Cells

2011 ◽  
Vol 79 (10) ◽  
pp. 4081-4087 ◽  
Author(s):  
Craig Weinkauf ◽  
Ryan Salvador ◽  
Mercio PereiraPerrin
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Mammalian Cells ◽  
Chinese Hamster ◽  
Neuronal Cell ◽  
Host Cells ◽  
Neurotrophin Receptor ◽  
Content Type

ABSTRACTTrypanosoma cruzi, the agent of Chagas' disease, infects a variety of mammalian cells in a process that includes multiple cycles of intracellular division and differentiation starting with host receptor recognition by a parasite ligand(s). Earlier work in our laboratory showed that the neurotrophin-3 (NT-3) receptor TrkC is activated byT. cruzisurfacetrans-sialidase, also known as parasite-derived neurotrophic factor (PDNF). However, it has remained unclear whether TrkC is used byT. cruzito enter host cells. Here, we show that a neuronal cell line (PC12-NNR5) relatively resistant toT. cruzibecame highly susceptible to infection when overexpressing human TrkC but not human TrkB. Furthermore,trkCtransfection conferred an ∼3.0-fold intracellular growth advantage. Sialylation-deficient Chinese hamster ovarian (CHO) epithelial cell lines Lec1 and Lec2 also became much more permissive toT. cruziafter transfection with thetrkCgene. Additionally, NT-3 specifically blockedT. cruziinfection of the TrkC-NNR5 transfectants and of naturally permissive TrkC-bearing Schwann cells and astrocytes, as did recombinant PDNF. Two specific inhibitors of Trk autophosphorylation (K252a and AG879) and inhibitors of Trk-induced MAPK/Erk (U0126) and Akt kinase (LY294002) signaling, but not an inhibitor of insulin-like growth factor 1 receptor, abrogated TrkC-mediated cell invasion. Antibody to TrkC blockedT. cruziinfection of the TrkC-NNR5 transfectants and of cells that naturally express TrkC. The TrkC antibody also significantly and specifically reduced cutaneous infection in a mouse model of acute Chagas' disease. TrkC is ubiquitously expressed in the peripheral and central nervous systems, and in nonneural cells infected byT. cruzi, including cardiac and gastrointestinal muscle cells. Thus, TrkC is implicated as a functional PDNF receptor in cell entry, independently of sialic acid recognition, mediating broadT. cruziinfection bothin vitroandin vivo.

scholarly journals SpyAD, a Moonlighting Protein of Group A Streptococcus Contributing to Bacterial Division and Host Cell Adhesion

2014 ◽  
Vol 82 (7) ◽  
pp. 2890-2901 ◽  
Author(s):  
Marilena Gallotta ◽  
Giovanni Gancitano ◽  
Giampiero Pietrocola ◽  
Marirosa Mora ◽  
Alfredo Pezzicoli ◽  
...  
Keyword(s):  
Cell Division ◽  
Mammalian Cells ◽  
Group A Streptococcus ◽  
Host Cells ◽  
Knockout Mutant ◽  
Content Type ◽  
Moonlighting Protein ◽  
Group A

ABSTRACTGroup A streptococcus (GAS) is a human pathogen causing a wide repertoire of mild and severe diseases for which no vaccine is yet available. We recently reported the identification of three protein antigens that in combination conferred wide protection against GAS infection in mice. Here we focused our attention on the characterization of one of these three antigens, Spy0269, a highly conserved, surface-exposed, and immunogenic protein of unknown function. Deletion of thespy0269gene in a GAS M1 isolate resulted in very long bacterial chains, which is indicative of an impaired capacity of the knockout mutant to properly divide. Confocal microscopy and immunoprecipitation experiments demonstrated that the protein was mainly localized at the cell septum and could interactin vitrowith the cell division protein FtsZ, leading us to hypothesize that Spy0269 is a member of the GAS divisome machinery. Predicted structural domains and sequence homologies with known streptococcal adhesins suggested that this antigen could also play a role in mediating GAS interaction with host cells. This hypothesis was confirmed by showing that recombinant Spy0269 could bind to mammalian epithelial cellsin vitroand thatLactococcus lactisexpressing Spy0269 on its cell surface could adhere to mammalian cellsin vitroand to mice nasal mucosain vivo. On the basis of these data, we believe that Spy0269 is involved both in bacterial cell division and in adhesion to host cells and we propose to rename this multifunctional moonlighting protein as SpyAD (StreptococcuspyogenesAdhesion andDivision protein).

scholarly journals AFM-Based Correlative Microscopy Illuminates Human Pathogens

2021 ◽  
Vol 11 ◽  
Author(s):  
Supriya V. Bhat ◽  
Jared D. W. Price ◽  
Tanya E. S. Dahms
Keyword(s):  
Optical Microscopy ◽  
Disease Transmission ◽  
Fitness Landscape ◽  
Host Cells ◽  
Full Potential ◽  
Correlative Microscopy ◽  
Human Pathogens ◽  
Host Pathogen Interactions ◽  
Host Pathogen ◽  
The Many

Microbes have an arsenal of virulence factors that contribute to their pathogenicity. A number of challenges remain to fully understand disease transmission, fitness landscape, antimicrobial resistance and host heterogeneity. A variety of tools have been used to address diverse aspects of pathogenicity, from molecular host-pathogen interactions to the mechanisms of disease acquisition and transmission. Current gaps in our knowledge include a more direct understanding of host-pathogen interactions, including signaling at interfaces, and direct phenotypic confirmation of pathogenicity. Correlative microscopy has been gaining traction to address the many challenges currently faced in biomedicine, in particular the combination of optical and atomic force microscopy (AFM). AFM, generates high-resolution surface topographical images, and quantifies mechanical properties at the pN scale under physiologically relevant conditions. When combined with optical microscopy, AFM probes pathogen surfaces and their physical and molecular interaction with host cells, while the various modes of optical microscopy view internal cellular responses of the pathogen and host. Here we review the most recent advances in our understanding of pathogens, recent applications of AFM to the field, how correlative AFM-optical microspectroscopy and microscopy have been used to illuminate pathogenicity and how these methods can reach their full potential for studying host-pathogen interactions.

scholarly journals The complex, bidirectional role of extracellular vesicles in infection

2021 ◽  
Author(s):  
Joni Renee White ◽  
Priscila Dauros-Singorenko ◽  
Jiwon Hong ◽  
Frédérique Vanholsbeeck ◽  
Anthony Phillips ◽  
...  
Keyword(s):  
Immune Response ◽  
Extracellular Vesicles ◽  
Bacterial Pathogens ◽  
Host Cells ◽  
Signalling Molecules ◽  
Host Pathogen ◽  
Domains Of Life

Cells from all domains of life release extracellular vesicles (EVs), packages that carry a cargo of molecules that participate in communication, co-ordination of population behaviours, virulence and immune response mechanisms. Mammalian EVs play an increasingly recognised role to fight infection, yet may also be commandeered to disseminate pathogens and enhance infection. EVs released by bacterial pathogens may deliver toxins to host cells, signalling molecules and new DNA to other bacteria, and act as decoys, protecting infecting bacteria from immune killing. In this review, we explore the role of EVs in infection from the perspective of both the pathogen and host, and highlight their importance in the host/pathogen relationship. We highlight proposed strategies for EVs in therapeutics, and call attention to areas where existing knowledge and evidence is lacking.

scholarly journals A host type I interferon response is induced by cytosolic sensing of the bacterial second messenger cyclic-di-GMP

2009 ◽  
Vol 206 (9) ◽  
pp. 1899-1911 ◽  
Author(s):  
Sarah M. McWhirter ◽  
Roman Barbalat ◽  
Kathryn M. Monroe ◽  
Mary F. Fontana ◽  
Mamoru Hyodo ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Map Kinases ◽  
Second Messenger ◽  
Innate Immune ◽  
Guanosine Monophosphate ◽  
Host Cells ◽  
Type I Interferons ◽  
Interferon Response ◽  
Type I

The innate immune system responds to unique molecular signatures that are widely conserved among microbes but that are not normally present in host cells. Compounds that stimulate innate immune pathways may be valuable in the design of novel adjuvants, vaccines, and other immunotherapeutics. The cyclic dinucleotide cyclic-di–guanosine monophosphate (c-di-GMP) is a recently appreciated second messenger that plays critical regulatory roles in many species of bacteria but is not produced by eukaryotic cells. In vivo and in vitro studies have previously suggested that c-di-GMP is a potent immunostimulatory compound recognized by mouse and human cells. We provide evidence that c-di-GMP is sensed in the cytosol of mammalian cells via a novel immunosurveillance pathway. The potency of cytosolic signaling induced by c-di-GMP is comparable to that induced by cytosolic delivery of DNA, and both nucleic acids induce a similar transcriptional profile, including triggering of type I interferons and coregulated genes via induction of TBK1, IRF3, nuclear factor κB, and MAP kinases. However, the cytosolic pathway that senses c-di-GMP appears to be distinct from all known nucleic acid–sensing pathways. Our results suggest a novel mechanism by which host cells can induce an inflammatory response to a widely produced bacterial ligand.

scholarly journals MgrA Governs Adherence, Host Cell Interaction, and Virulence in a Murine Model of Bacteremia Due to Staphylococcus aureus

2019 ◽  
Vol 220 (6) ◽  
pp. 1019-1028 ◽  
Author(s):  
Liang Li ◽  
Genzhu Wang ◽  
Ambrose Cheung ◽  
Wessam Abdelhady ◽  
Kati Seidl ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Protein A ◽  
Virulence Gene ◽  
Toxin Production ◽  
Cell Interaction ◽  
Host Pathogen Interactions ◽  
Host Pathogen ◽  
Direct Binding ◽  
The Impact

AbstractBackgroundMgrA is an important global virulence gene regulator in Staphylococcus aureus. In the present study, the role of mgrA in host-pathogen interactions related to virulence was explored in both methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) strains.MethodsIn vitro susceptibilities to human defense peptides (HDPs), adherence to fibronectin (Fn) and endothelial cells (ECs), EC damage, α-toxin production, expression of global regulator (eg, agr RNAIII) and its downstream effectors (eg, α-toxin [hla] and Fn binding protein A [fnbA]), MgrA binding to fnbA promoter, and the effect on HDP-induced mprF and dltA expression were analyzed. The impact of mgrA on virulence was evaluated using a mouse bacteremia model.ResultsmgrA mutants displayed significantly higher susceptibility to HDPs, which might be related to the decreased HDP-induced mprF and dltA expression but decreased Fn and EC adherence, EC damage, α-toxin production, agr RNAIII, hla and fnbA expression, and attenuated virulence in the bacteremia model as compared to their respective parental and mgrA-complemented strains. Importantly, direct binding of MgrA to the fnbA promoter was observed.ConclusionsThese results suggest that mgrA mediates host-pathogen interactions and virulence and may provide a novel therapeutic target for invasive S. aureus infections.

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