Proteases of Sporothrix schenckii : Cytopathological effects on a host-cell model

Physiological changes in host cell model membranes (intact human erythrocytes and ghosts) as a consequence of bacterial adhesion were studied with special reference to Neisseria gonorrhoeae. Membrane activities examined were transport of K+, Cl− ions, pyruvate kinase, Na–K-dependent ATPase, and cAMP. We found that K+ and Cl− transport were affected, more so in membranes with attached pilated (P+) organisms than in those with apilated (P−) isogenic strains. In N. gonorrhoeae and in several other species of gram-negative bacteria studied, hemagglutination titres were directly correlated with effects on anion transport, suggesting that perturbations in anion transport are an immediate result of adhesion. Of three P+ gonococcus strains tested, two depressed Na–K–ATPase activity in the membrane, indicating a possible effect on the Na–K pump. Pyruvate kinase activity associated with the membrane appeared to be stimulated by attached gonococci, again by P+ strains to higher levels than P− organisms. Clearly, some enzyme properties of host membranes are intrinsically affected by bacterial adhesion. Human polymorphonuclear neutrophils were also investigated, and with some exceptions, changes observed in leukocyte enzyme activities tended to parallel those in erythrocytes. Since hypochlorous acid production is considered to be an important microbicidal mechanism in neutrophils, interference with Cl− transport could jeopardize their role in host defense.

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A Cellular Model of Infection with Brucella melitensis in Ovine Macrophages: Novel Insights for Intracellular Bacterial Detection

Veterinary Sciences ◽

10.3390/vetsci6030071 ◽

2019 ◽

Vol 6 (3) ◽

pp. 71 ◽

Cited By ~ 2

Author(s):

Garyfalia Karponi ◽

Spyridon K. Kritas ◽

Eleni Papanikolaou ◽

Evanthia Petridou

Keyword(s):

Host Cell ◽

Post Infection ◽

Cell Model ◽

Brucella Melitensis ◽

Financial Burden ◽

Cell Tropism ◽

Inflammatory Reactions ◽

Bactericidal Properties ◽

Future Utilization

Intracellular bacteria provoking zoonoses, such as those of the genus Brucella, present a host cell tropism mostly limited to the monocyte/macrophage lineage, leading to chronic inflammatory reactions, difficult-to-eradicate-infections, and widespread prevalence among ruminants. Eradication of brucellosis has been based on programs that translate into a substantial financial burden for both the authorities and stockbreeders, if not strictly followed. To this end, we sought to create an in vitro cell model that could be utilized as future reference for adequately measuring the number of engulfed brucellae/cell, using peripheral blood-derived sheep macrophages infected with B. melitensis at decimal multiplicities of infection (MOI = 5000-5), to simulate the host cell/microorganism interaction and monitor bacterial loads up to 6 days post-infection. We show that the MOI = 5000 leads to high numbers of engulfed bacteria without affecting macrophages’ viability and that the minimum detection limit of our Real-Time PCR assay was 3.97 ± 5.58 brucellae/cell. Moreover, we observed a time-associated, significant gradual reduction in bacterial loads from Day 2 to Day 6 post-infection (p = 0.0013), as part of the natural bactericidal properties of macrophages. Overall, the work presented here constitutes a reliable in vitro cell model of Brucella melitensis for research purposes that can be utilized to adequately measure the number of engulfed brucellae/cell and provides insights towards future utilization of molecular biology-based methods for detection of Brucella.

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Host Cell Fate on Cryptosporidium parvum Egress from MDCK Cells

Infection and Immunity ◽

10.1128/iai.71.9.5422-5426.2003 ◽

2003 ◽

Vol 71 (9) ◽

pp. 5422-5426 ◽

Cited By ~ 13

Author(s):

David A. Elliott ◽

Douglas P. Clark

Keyword(s):

Host Cell ◽

Cell Fate ◽

Cryptosporidium Parvum ◽

Mdck Cell ◽

Cell Model ◽

Mdck Cells ◽

Protozoan Parasite ◽

Unclear Etiology ◽

Parasite Egress ◽

Intracellular Protozoan Parasite

ABSTRACT Cryptosporidium parvum is an intracellular protozoan parasite that causes a severe diarrheal illness of unclear etiology. Also unclear is the fate of the host cell upon parasite egress. We show in an MDCK cell model that the host cell is killed upon parasite egress; this death is necrotic, rather than apoptotic, in nature.

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Drug repurposing screens identify chemical entities for the development of COVID-19 interventions

Nature Communications ◽

10.1038/s41467-021-23328-0 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Malina A. Bakowski ◽

Nathan Beutler ◽

Karen C. Wolff ◽

Melanie G. Kirkpatrick ◽

Emily Chen ◽

...

Keyword(s):

Host Cell ◽

Cell Model ◽

Drug Repurposing ◽

Therapeutic Drug ◽

The Novel ◽

Hamster Model ◽

Drug Candidates ◽

Lung Epithelial ◽

Direct Acting

AbstractThe ongoing pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), necessitates strategies to identify prophylactic and therapeutic drug candidates for rapid clinical deployment. Here, we describe a screening pipeline for the discovery of efficacious SARS-CoV-2 inhibitors. We screen a best-in-class drug repurposing library, ReFRAME, against two high-throughput, high-content imaging infection assays: one using HeLa cells expressing SARS-CoV-2 receptor ACE2 and the other using lung epithelial Calu-3 cells. From nearly 12,000 compounds, we identify 49 (in HeLa-ACE2) and 41 (in Calu-3) compounds capable of selectively inhibiting SARS-CoV-2 replication. Notably, most screen hits are cell-line specific, likely due to different virus entry mechanisms or host cell-specific sensitivities to modulators. Among these promising hits, the antivirals nelfinavir and the parent of prodrug MK-4482 possess desirable in vitro activity, pharmacokinetic and human safety profiles, and both reduce SARS-CoV-2 replication in an orthogonal human differentiated primary cell model. Furthermore, MK-4482 effectively blocks SARS-CoV-2 infection in a hamster model. Overall, we identify direct-acting antivirals as the most promising compounds for drug repurposing, additional compounds that may have value in combination therapies, and tool compounds for identification of viral host cell targets.

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A Spectroscopic Study of the Aggregation State of the Human Antimicrobial Peptide LL-37 in Bacterial versus Host Cell Model Membranes

Biochemistry ◽

10.1021/acs.biochem.5b00813 ◽

2015 ◽

Vol 54 (45) ◽

pp. 6760-6768 ◽

Cited By ~ 12

Author(s):

Alessio Bonucci ◽

Elena Caldaroni ◽

Enrico Balducci ◽

Rebecca Pogni

Keyword(s):

Antimicrobial Peptide ◽

Spectroscopic Study ◽

Host Cell ◽

Cell Model ◽

Model Membranes ◽

Aggregation State

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Bacteriophages Associated with Turkey Coecums in Bluecomb-Infected and Healthy Birds

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063044 ◽

1969 ◽

Vol 27 ◽

pp. 226-227

Author(s):

A. E. Ritchie

Keyword(s):

Host Cell ◽

Causal Relationship ◽

Cell Cultures ◽

Cell Interaction ◽

Etiologic Agent ◽

Viral Origin ◽

Intestinal Contents ◽

Host Cell Interaction

The cause of bluecomb disease in turkeys is unknown. Filtration of infective intestinal contents suggests a viral origin. To date, it has not been possible to isolate the etiologic agent in various cell cultures. The purpose of this work was to characterize as many virus-like entities as were recognizable in intestines of both healthy and bluecomb-infected turkeys. By a comparison of the viral populations it was hoped that some insight might be gained into the cause of this disease. Studies of turkey hemorraghic enteritis by Gross and Moore (Avian Dis. 11: 296-307, 1967) have suggested that a bacteriophage-host cell interaction may bear some causal relationship to that disease.

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The Infection of Cells by Bullet-Shaped Viruses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063779 ◽

1969 ◽

Vol 27 ◽

pp. 372-373

Author(s):

Frederick A. Murphy ◽

Alyne K. Harrison ◽

Sylvia G. Whitfield

Keyword(s):

Electron Microscopy ◽

Physical Properties ◽

Host Cell ◽

Thin Section ◽

Cultured Cells ◽

Cell Infection ◽

Thin Section Electron Microscopy ◽

Section Electron ◽

Section Electron Microscopy

The bullet-shaped viruses are currently classified together on the basis of similarities in virion morphology and physical properties. Biologically and ecologically the member viruses are extremely diverse. In searching for further bases for making comparisons of these agents, the nature of host cell infection, both in vivo and in cultured cells, has been explored by thin-section electron microscopy.

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Endogenous hydrogen sulfide sulfhydrates IKKβ at cysteine 179 to control pulmonary artery endothelial cell inflammation

Clinical Science ◽

10.1042/cs20190514 ◽

2019 ◽

Vol 133 (20) ◽

pp. 2045-2059 ◽

Cited By ~ 4

Author(s):

Da Zhang ◽

Xiuli Wang ◽

Siyao Chen ◽

Selena Chen ◽

Wen Yu ◽

...

Keyword(s):

Hydrogen Sulfide ◽

Endothelial Cell ◽

Pulmonary Artery ◽

Cell Model ◽

Site Directed Mutagenesis ◽

Critical Event ◽

Hypertensive Rats ◽

Pulmonary Artery Endothelial Cell

Abstract Background: Pulmonary artery endothelial cell (PAEC) inflammation is a critical event in the development of pulmonary arterial hypertension (PAH). However, the pathogenesis of PAEC inflammation remains unclear. Methods: Purified recombinant human inhibitor of κB kinase subunit β (IKKβ) protein, human PAECs and monocrotaline-induced pulmonary hypertensive rats were employed in the study. Site-directed mutagenesis, gene knockdown or overexpression were conducted to manipulate the expression or activity of a target protein. Results: We showed that hydrogen sulfide (H2S) inhibited IKKβ activation in the cell model of human PAEC inflammation induced by monocrotaline pyrrole-stimulation or knockdown of cystathionine γ-lyase (CSE), an H2S generating enzyme. Mechanistically, H2S was proved to inhibit IKKβ activity directly via sulfhydrating IKKβ at cysteinyl residue 179 (C179) in purified recombinant IKKβ protein in vitro, whereas thiol reductant dithiothreitol (DTT) reversed H2S-induced IKKβ inactivation. Furthermore, to demonstrate the significance of IKKβ sulfhydration by H2S in the development of PAEC inflammation, we mutated C179 to serine (C179S) in IKKβ. In purified IKKβ protein, C179S mutation of IKKβ abolished H2S-induced IKKβ sulfhydration and the subsequent IKKβ inactivation. In human PAECs, C179S mutation of IKKβ blocked H2S-inhibited IKKβ activation and PAEC inflammatory response. In pulmonary hypertensive rats, C179S mutation of IKKβ abolished the inhibitory effect of H2S on IKKβ activation and pulmonary vascular inflammation and remodeling. Conclusion: Collectively, our in vivo and in vitro findings demonstrated, for the first time, that endogenous H2S directly inactivated IKKβ via sulfhydrating IKKβ at Cys179 to inhibit nuclear factor-κB (NF-κB) pathway activation and thereby control PAEC inflammation in PAH.

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