scholarly journals Nonprofessional Phagocytic Cell Receptors Involved inStaphylococcus aureusInternalization

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Nayeli Alva-Murillo ◽  
Joel Edmundo López-Meza ◽  
Alejandra Ochoa-Zarzosa
Keyword(s):  
Staphylococcus Aureus ◽  
Host Cell ◽  
Soft Tissues ◽  
Scavenger Receptor ◽  
Host Cells ◽  
Phagocytic Cell ◽  
Phagocytic Cells ◽  
Cell Receptors ◽  
Life Threatening ◽  
Bacterial Effectors

Staphylococcus aureusis a successful human and animal pathogen. The majority of infections caused by this pathogen are life threatening, primarily becauseS. aureushas developed multiple evasion strategies, possesses intracellular persistence for long periods, and targets the skin and soft tissues. Therefore, it is very important to understand the mechanisms employed byS. aureusto colonize and proliferate in these cells. The aim of this review is to describe the recent discoveries concerning the host receptors of nonprofessional phagocytes involved inS. aureusinternalization. Most of the knowledge related to the interaction ofS. aureuswith its host cells has been described in professional phagocytic cells such as macrophages. Here, we showed that in nonprofessional phagocytes theα5β1 integrin host receptor, chaperons, and the scavenger receptor CD36 are the main receptors employed duringS. aureusinternalization. The characterization and identification of new bacterial effectors and the host cell receptors involved will undoubtedly lead to new discoveries with beneficial purposes.

scholarly journals Intracellular Staphylococcus aureus employs the cysteine protease staphopain A to induce host cell death in epithelial cells

2021 ◽  
Vol 17 (9) ◽  
pp. e1009874
Author(s):  
Kathrin Stelzner ◽  
Aziza Boyny ◽  
Tobias Hertlein ◽  
Aneta Sroka ◽  
Adriana Moldovan ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Death ◽  
Epithelial Cells ◽  
Host Cell ◽  
Cysteine Protease ◽  
Host Cells ◽  
Intracellular Replication ◽  
Tissue Destruction ◽  
Phagocytic Cells ◽  
Host Cell Death

Staphylococcus aureus is a major human pathogen, which can invade and survive in non-professional and professional phagocytes. Uptake by host cells is thought to contribute to pathogenicity and persistence of the bacterium. Upon internalization by epithelial cells, cytotoxic S. aureus strains can escape from the phagosome, replicate in the cytosol and induce host cell death. Here, we identified a staphylococcal cysteine protease to induce cell death after translocation of intracellular S. aureus into the host cell cytoplasm. We demonstrated that loss of staphopain A function leads to delayed onset of host cell death and prolonged intracellular replication of S. aureus in epithelial cells. Overexpression of staphopain A in a non-cytotoxic strain facilitated intracellular killing of the host cell even in the absence of detectable intracellular replication. Moreover, staphopain A contributed to efficient colonization of the lung in a mouse pneumonia model. In phagocytic cells, where intracellular S. aureus is exclusively localized in the phagosome, staphopain A did not contribute to cytotoxicity. Our study suggests that staphopain A is utilized by S. aureus to exit the epithelial host cell and thus contributes to tissue destruction and dissemination of infection.

scholarly journals Toxoplasma gondii Development of Its Replicative Niche: in Its Host Cell and Beyond

2014 ◽  
Vol 13 (8) ◽  
pp. 965-976 ◽  
Author(s):  
Ira J. Blader ◽  
Anita A. Koshy
Keyword(s):  
Toxoplasma Gondii ◽  
Host Cell ◽  
Host Cells ◽  
Content Type ◽  
Obligate Intracellular ◽  
Cellular Processes ◽  
High Prevalence ◽  
Life Threatening ◽  
Cell Processes ◽  
Cellular Pathways

ABSTRACTIntracellular pathogens can replicate efficiently only after they manipulate and modify their host cells to create an environment conducive to replication. While diverse cellular pathways are targeted by different pathogens, metabolism, membrane and cytoskeletal architecture formation, and cell death are the three primary cellular processes that are modified by infections.Toxoplasma gondiiis an obligate intracellular protozoan that infects ∼30% of the world's population and causes severe and life-threatening disease in developing fetuses, in immune-comprised patients, and in certain otherwise healthy individuals who are primarily found in South America. The high prevalence ofToxoplasmain humans is in large part a result of its ability to modulate these three host cell processes. Here, we highlight recent work defining the mechanisms by whichToxoplasmainteracts with these processes. In addition, we hypothesize why some processes are modified not only in the infected host cell but also in neighboring uninfected cells.

scholarly journals Invasion of the Brain by Listeria monocytogenes Is Mediated by InlF and Host Cell Vimentin

mBio ◽  
2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Pallab Ghosh ◽  
Elizabeth M. Halvorsen ◽  
Dustin A. Ammendolia ◽  
Nirit Mor-Vaknin ◽  
Mary X. D. O’Riordan ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Host Cell ◽  
Bacterial Pathogen ◽  
Surface Protein ◽  
Host Cells ◽  
Intermediate Filament Protein ◽  
Life Threatening ◽  
Host Cell Surface ◽  
Filament Protein ◽  
The Brain

ABSTRACTListeria monocytogenesis a facultative intracellular bacterial pathogen that is frequently associated with food-borne infection. Of particular concern is the ability ofL. monocytogenesto breach the blood-brain barrier, leading to life-threatening meningitis and encephalitis. The mechanisms used by bacterial pathogens to infect the brain are not fully understood. Here we show thatL. monocytogenesis able to utilize vimentin for invasion of host cells. Vimentin is a type III intermediate filament protein within the cytosol but is also expressed on the host cell surface. We found thatL. monocytogenesinteraction with surface-localized vimentin promoted bacterial uptake. Furthermore, in the absence of vimentin,L. monocytogenescolonization of the brain was severely compromised in mice. TheL. monocytogenesvirulence factor InlF was found to bind vimentin and was necessary for optimal bacterial colonization of the brain. These studies reveal a novel receptor-ligand interaction that enhances infection of the brain byL. monocytogenesand highlights the importance of surface vimentin in host-pathogen interactions.IMPORTANCEListeria monocytogenesis an intracellular bacterial pathogen that is capable of invading numerous host cells during infection.L. monocytogenescan cross the blood-brain barrier, leading to life-threatening meningitis. Here we show that anL. monocytogenessurface protein, InlF, is necessary for optimal colonization of the brain in mice. Furthermore, in the absence of vimentin, a cytosolic intermediate filament protein that is also present on the surface of brain endothelial cells, colonization of the brain was significantly impaired. We further show that InlF binds vimentin to mediate invasion of host cells. This work identifies InlF as a bacterial surface protein with specific relevance for infection of the brain and underscores the significance of host cell surface vimentin interactions in microbial pathogenesis.

Salmonella in Australia: understanding and controlling infection

2017 ◽  
Vol 38 (3) ◽  
pp. 112
Author(s):  
Joshua PM Newson
Keyword(s):  
Host Cell ◽  
Cell Biology ◽  
Protein Translocation ◽  
Cell Signalling ◽  
Effector Proteins ◽  
Host Cells ◽  
Secretion Systems ◽  
Significant Burden ◽  
Systemic Infections ◽  
Bacterial Effectors

The bacterium Salmonella causes a spectrum of foodborne diseases ranging from acute gastroenteritis to systemic infections, and represents a significant burden of disease globally. In Australia, Salmonella is frequently associated with outbreaks and is a leading cause of foodborne illness, which results in a significant medical and economic burden. Salmonella infection involves colonisation of the small intestine, where the bacteria invades host cells and establishes an intracellular infection. To survive within host cells, Salmonella employs type-three secretion systems to deliver bacterial effector proteins into the cytoplasm of host cells. These bacterial effectors seek out and modify specific host proteins, disrupting host processes such as cell signalling, intracellular trafficking, and programmed cell death. This strategy of impairing host cells allows Salmonella to establish a replicative niche within the cell, where they can replicate to high numbers before escaping to infect neighbouring cells, or be transmitted to new hosts. While the importance of effector protein translocation to infection is well established, our understanding of many effector proteins remains incomplete. Many Salmonella effectors have unknown function and unknown roles during infection. A greater understanding of how Salmonella manipulates host cells during infection will lead to improved strategies to prevent, control, and eliminate disease. Further, studying effector proteins can be a useful means for exploring host cell biology and elucidating the details of host cell signalling.

scholarly journals Competitive adherence as a mechanism of bacterial interference

1983 ◽  
Vol 29 (6) ◽  
pp. 700-703 ◽  
Author(s):  
Debra Jan Bibel ◽  
Raza Aly ◽  
Charlene Bayles ◽  
Walter G. Strauss ◽  
Henry R. Shinefield ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Host Cell ◽  
Virulent Strain ◽  
Host Cells ◽  
Aureus Strain ◽  
Attachment Sites ◽  
Specific Attachment ◽  
Mucosal Cells ◽  
Bacterial Interference

To determine whether competition among bacteria for specific attachment sites on host cells can explain bacterial interference, Staphylococcus aureus strain 502A was tested in turn against two different nasal coryneforms, a strain of Pseudomonas aeruginosa, and a virulent strain of S. aureus, all in the presence of nasal mucosal cells. Particularly examined was the influence of sequence in which bacteria were presented to the nasal cells in comparison with initial mixtures and individual suspensions. Results paralleled those observed in clinical prophylaxis: the bacterium first to adhere to the epithelial cells was able, under uniform conditions, to interfere with the colonization of subsequently added bacteria. Secondary adherence was not eliminated but substantially reduced, and was probably related to steric blockage by the initial colonizer and its particular ability to dissociate from the host cell.

scholarly journals Intracellular Staphylococcus aureus employs the cysteine protease staphopain A to induce host cell death in epithelial cells

2020 ◽  
Author(s):  
Kathrin Stelzner ◽  
Tobias Hertlein ◽  
Aneta Sroka ◽  
Adriana Moldovan ◽  
Kerstin Paprotka ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Death ◽  
Epithelial Cells ◽  
Host Cell ◽  
Cysteine Protease ◽  
Host Cells ◽  
Upper Respiratory Tract ◽  
Intracellular Replication ◽  
Tissue Destruction ◽  
Host Cell Death

AbstractStaphylococcus aureus is a major human pathogen, which can invade and survive in non-professional and professional phagocytes. Intracellularity is thought to contribute to pathogenicity and persistence of the bacterium. Upon internalization by epithelial cells, cytotoxic S. aureus strains can escape from the phagosome, replicate in the cytosol and induce host cell death. Here, we identified a staphylococcal cysteine protease to induce cell death by intracellular S. aureus after translocation into the host cell cytoplasm. We demonstrated that loss of staphopain A function leads to delayed onset of host cell death and prolonged intracellular replication of S. aureus in epithelial cells. Overexpression of staphopain A in a non-cytotoxic strain facilitated intracellular killing of the host cell even in the absence of detectable intracellular replication. Moreover, staphopain A contributed to efficient colonization of the lung in a mouse pneumonia model. Our study suggests that staphopain A is utilized by S. aureus to mediate escape from the host cell and thus contributes to tissue destruction and dissemination of infection.Author SummaryStaphylococcus aureus is a well-known antibiotic-resistant pathogen that emerges in hospital and community settings and can cause a variety of diseases ranging from skin abscesses to lung inflammation and blood poisoning. The bacterium asymptomatically colonizes the upper respiratory tract and skin of about one third of the human population and takes advantage of opportune conditions, like immunodeficiency or breached barriers, to cause infection. Although S. aureus is not regarded as a professional intracellular bacterium, it can be internalized by human cells and subsequently exit the host cells by induction of cell death, which is considered to cause tissue destruction and spread of infection. The bacterial virulence factors and underlying molecular mechanisms involved in the intracellular lifestyle of S. aureus remain largely unknown. We identified a bacterial cysteine protease to contribute to host cell death mediated by intracellular S. aureus. Staphopain A induced killing of the host cell after translocation of the pathogen into the cell cytosol, while bacterial proliferation was not required. Further, the protease enhanced survival of the pathogen during lung infection. These findings reveal a novel, intracellular role for the bacterial protease staphopain A.

scholarly journals Undercover Agents of Infection: The Stealth Strategies of T4SS-Equipped Bacterial Pathogens

Toxins ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 713
Author(s):  
Arthur Bienvenu ◽  
Eric Martinez ◽  
Matteo Bonazzi
Keyword(s):  
Host Cell ◽  
Chronic Diseases ◽  
Bacterial Pathogens ◽  
Secretion System ◽  
Effector Proteins ◽  
Innate Immune ◽  
Host Cells ◽  
Immune Sensing ◽  
Bacterial Effectors ◽  
Innate Immune Sensing

Intracellular bacterial pathogens establish their replicative niches within membrane-encompassed compartments, called vacuoles. A subset of these bacteria uses a nanochannel called the type 4 secretion system (T4SS) to inject effector proteins that subvert the host cell machinery and drive the biogenesis of these compartments. These bacteria have also developed sophisticated ways of altering the innate immune sensing and response of their host cells, which allow them to cause long-lasting infections and chronic diseases. This review covers the mechanisms employed by intravacuolar pathogens to escape innate immune sensing and how Type 4-secreted bacterial effectors manipulate host cell mechanisms to allow the persistence of bacteria.

scholarly journals pH and Receptor Induced Conformational Changes-Implications Towards S1 Dissociation of SARS-CoV2 Spike Glycoprotein

2020 ◽  
Author(s):  
Jesu E. Castin ◽  
Daniel A. Gideon ◽  
Karthik S. Sudarsha ◽  
Sherlin A. Rosita
Keyword(s):  
Host Cell ◽  
Cell Fusion ◽  
Fusion Proteins ◽  
Proteolytic Enzymes ◽  
Host Cells ◽  
Viral Fusion ◽  
Health Crisis ◽  
S Protein ◽  
Viral Attachment ◽  
Cell Receptors

AbstractViruses, being obligate intracellular parasites, must first attach themselves and gain entry into host cells. Viral fusion machinery is the central player in the viral attachment process in almost every viral disease. Viruses have incorporated an array of efficient fusion proteins on their surfaces to bind efficiently to host cell receptors. They make use of the host proteolytic enzymes to rearrange their surface protein(s) into the form which facilitates their binding to host-cell membrane proteins and subsequently, fusion. This stage of viral entry is very critical and has many therapeutic implications. The current global pandemic of COVID-19 has sparked severe health crisis and economic shutdowns. SARS-CoV2, the etiological agent of the disease has led to millions of deaths and brought the scientific community together in an attempt to understand the mechanisms of SARS-CoV2 pathogenesis and mortality. Like other viral fusion machinery, CoV2 spike (S) glycoprotein- ‘The Demogorgon’ poses the same questions about viral-host cell fusion. The intermediate stages of S protein-mediated viral fusion are unclear owing to the lack of structural insights and concrete biochemical evidence. The mechanism of conformational transition is still unclear. S protein binding and fusion with host cell receptors, Eg., angiotensin-converting enzyme-2 (ACE2) is accompanied by cleavage of S1/S2 subunits. To track the key events of viral-host cell fusion, we have identified (in silico) that low pH-induced conformational change and ACE-2 binding events promote S1 dissociation. Deciphering key mechanistic insights of SARS-CoV2 fusion will further our understanding of other class-I fusion proteins

scholarly journals Selective Host Cell Death by Staphylococcus aureus: A Strategy for Bacterial Persistence

2021 ◽  
Vol 11 ◽  
Author(s):  
Dominique Missiakas ◽  
Volker Winstel
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Death ◽  
Host Cell ◽  
Intervention Strategies ◽  
Host Cells ◽  
Intracellular Killing ◽  
Mammalian Development ◽  
Cell Responses ◽  
Cell Death Pathways ◽  
Host Cell Death

Host cell death programs are fundamental processes that shape cellular homeostasis, embryonic development, and tissue regeneration. Death signaling and downstream host cell responses are not only critical to guide mammalian development, they often act as terminal responses to invading pathogens. Here, we briefly review and contrast how invading pathogens and specifically Staphylococcus aureus manipulate apoptotic, necroptotic, and pyroptotic cell death modes to establish infection. Rather than invading host cells, S. aureus subverts these cells to produce diffusible molecules that cause death of neighboring hematopoietic cells and thus shapes an immune environment conducive to persistence. The exploitation of cell death pathways by S. aureus is yet another virulence strategy that must be juxtaposed to mechanisms of immune evasion, autophagy escape, and tolerance to intracellular killing, and brings us closer to the true portrait of this pathogen for the design of effective therapeutics and intervention strategies.

scholarly journals ClpC affects the intracellular survival capacity of Staphylococcus aureus in non-professional phagocytic cells

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Gubesh Gunaratnam ◽  
Lorena Tuchscherr ◽  
Mohamed I. Elhawy ◽  
Ralph Bertram ◽  
Janina Eisenbeis ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Protein A ◽  
Intracellular Survival ◽  
Host Cells ◽  
Virulence Determinants ◽  
Phagocytic Cells ◽  
Survival Capacity ◽  
Shock Proteins ◽  
Mutant Cells

Abstract Invasion and persistence of bacteria within host cells requires that they adapt to life in an intracellular environment. This adaptation induces bacterial stress through events such as phagocytosis and enhanced nutrient-restriction. During stress, bacteria synthesize a family of proteins known as heat shock proteins (HSPs) to facilitate adaptation and survival. Previously, we determined the Staphylococcus aureus HSP ClpC temporally alters bacterial metabolism and persistence. This led us to hypothesize that ClpC might alter intracellular survival. Inactivation of clpC in S. aureus strain DSM20231 significantly enhanced long-term intracellular survival in human epithelial (HaCaT) and endothelial (EA.hy926) cell lines, without markedly affecting adhesion or invasion. This phenotype was similar across a genetically diverse collection of S. aureus isolates, and was influenced by the toxin/antitoxin encoding locus mazEF. Importantly, MazEF alters mRNA synthesis and/or stability of S. aureus virulence determinants, indicating ClpC may act through the mRNA modulatory activity of MazEF. Transcriptional analyses of total RNAs isolated from intracellular DSM20231 and isogenic clpC mutant cells identified alterations in transcription of α-toxin (hla), protein A (spa), and RNAIII, consistent with the hypothesis that ClpC negatively affects the intracellular survival of S. aureus in non-professional phagocytic cells, via modulation of MazEF and Agr.

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