scholarly journals EspJ Is a Prophage-Carried Type III Effector Protein of Attaching and Effacing Pathogens That Modulates Infection Dynamics

2005 ◽  
Vol 73 (2) ◽  
pp. 679-686 ◽  
Author(s):  
Sivan Dahan ◽  
Siouxsie Wiles ◽  
Roberto M. La Ragione ◽  
Angus Best ◽  
Martin J. Woodward ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Ex Vivo ◽  
Pathogen Transmission ◽  
Effector Proteins ◽  
In Vivo Studies ◽  
E Coli ◽  
Type Iii ◽  
Infection Dynamics ◽  
Enterocyte Effacement

ABSTRACT Enterohemorrhagic Escherichia coli, enteropathogenic E. coli, and Citrobacter rodentium are highly adapted enteropathogens that successfully colonize their host's gastrointestinal tract via the formation of attaching and effacing (A/E) lesions. These pathogens utilize a type III secretion system (TTSS) apparatus, encoded by the locus of enterocyte effacement, to translocate bacterial effector proteins into epithelial cells. Here, we report the identification of EspJ (E. coli-secreted protein J), a translocated TTSS effector that is carried on the 5′ end of the cryptic prophage CP-933U. Infection of epithelial cells in culture revealed that EspJ is not required for A/E lesion activity in vivo and ex vivo. However, in vivo studies performed with mice demonstrated that EspJ possesses properties that influence the dynamics of clearance of the pathogen from the host's intestinal tract, suggesting a role in host survival and pathogen transmission.

scholarly journals Tandem Translation Generates a Chaperone for the Salmonella Type III Secretion System Protein SsaQ

2011 ◽  
Vol 286 (41) ◽  
pp. 36098-36107 ◽  
Author(s):  
Xiu-Jun Yu ◽  
Mei Liu ◽  
Steve Matthews ◽  
David W. Holden
Keyword(s):  
Type Iii Secretion ◽  
Ex Vivo ◽  
Eukaryotic Cell ◽  
Effector Proteins ◽  
Secretion Systems ◽  
Type Iii ◽  
Type Iii Secretion Systems ◽  
Function Loss ◽  
Bacterial Cytoplasm

Type III secretion systems (T3SSs) of bacterial pathogens involve the assembly of a surface-localized needle complex, through which translocon proteins are secreted to form a pore in the eukaryotic cell membrane. This enables the transfer of effector proteins from the bacterial cytoplasm to the host cell. A structure known as the C-ring is thought to have a crucial role in secretion by acting as a cytoplasmic sorting platform at the base of the T3SS. Here, we studied SsaQ, an FliN-like putative C-ring protein of the Salmonella pathogenicity island 2 (SPI-2)-encoded T3SS. ssaQ produces two proteins by tandem translation: a long form (SsaQL) composed of 322 amino acids and a shorter protein (SsaQS) comprising the C-terminal 106 residues of SsaQL. SsaQL is essential for SPI-2 T3SS function. Loss of SsaQS impairs the function of the T3SS both ex vivo and in vivo. SsaQS binds to its corresponding region within SsaQL and stabilizes the larger protein. Therefore, SsaQL function is optimized by a novel chaperone-like protein, produced by tandem translation from its own mRNA species.

scholarly journals A Degenerate Type III Secretion System from Septicemic Escherichia coli Contributes to Pathogenesis

2005 ◽  
Vol 187 (23) ◽  
pp. 8164-8171 ◽  
Author(s):  
Diana Ideses ◽  
Uri Gophna ◽  
Yossi Paitan ◽  
Roy R. Chaudhuri ◽  
Mark J. Pallen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Gene Clusters ◽  
Secretion System ◽  
Effector Proteins ◽  
E Coli ◽  
Type Iii

ABSTRACT The type III secretion system (T3SS) is an important virulence factor used by several gram-negative bacteria to deliver effector proteins which subvert host cellular processes. Enterohemorrhagic Escherichia coli O157 has a well-defined T3SS involved in attachment and effacement (ETT1) and critical for virulence. A gene cluster potentially encoding an additional T3SS (ETT2), which resembles the SPI-1 system in Salmonella enterica, was found in its genome sequence. The ETT2 gene cluster has since been found in many E. coli strains, but its in vivo role is not known. Many of the ETT2 gene clusters carry mutations and deletions, raising the possibility that they are not functional. Here we show the existence in septicemic E. coli strains of an ETT2 gene cluster, ETT2sepsis, which, although degenerate, contributes to pathogenesis. ETT2sepsis has several premature stop codons and a large (5 kb) deletion, which is conserved in 11 E. coli strains from cases of septicemia and newborn meningitis. A null mutant constructed to remove genes coding for the putative inner membrane ring of the secretion complex exhibited significantly reduced virulence. These results are the first demonstration of the importance of ETT2 for pathogenesis.

scholarly journals Distribution, Functional Expression, and Genetic Organization of Cif, a Phage-Encoded Type III-Secreted Effector from Enteropathogenic and Enterohemorrhagic Escherichia coli

2007 ◽  
Vol 190 (1) ◽  
pp. 275-285 ◽  
Author(s):  
Estelle Loukiadis ◽  
Rika Nobe ◽  
Sylvia Herold ◽  
Clara Tramuta ◽  
Yoshitoshi Ogura ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Functional Expression ◽  
Effector Proteins ◽  
Enterohemorrhagic Escherichia Coli ◽  
Host Cells ◽  
E Coli ◽  
Type Iii ◽  
Related Phenotype ◽  
Enterocyte Effacement ◽  
Lambdoid Prophage

ABSTRACT Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) inject effector proteins into host cells via a type III secretion system encoded by the locus of enterocyte effacement (LEE). One of these effectors is Cif, encoded outside the LEE by a lambdoid prophage. In this study, we demonstrated that the Cif-encoding prophage of EPEC strain E22 is inducible and produces infectious phage particles. We investigated the distribution and functional expression of Cif in 5,049 E. coli strains of human, animal, and environmental origins. A total of 115 E. coli isolates from diverse origins and geographic locations carried cif. The presence of cif was tightly associated with the LEE, since all the cif-positive isolates were positive for the LEE. These results suggested that the Cif-encoding prophages have been widely disseminated within the natural population of E. coli but positively selected within the population of LEE-positive strains. Nonetheless, 66% of cif-positive E. coli strains did not induce a typical Cif-related phenotype in eukaryotic cells due to frameshift mutations or insertion of an IS element in the cif gene. The passenger region of the prophages carrying cif was highly variable and showed various combinations of IS elements and genes coding for other effectors such as nleB, nleC, nleH, nleG, espJ, and nleA/espI (some of which were also truncated). This diversity and the presence of nonfunctional effectors should be taken into account to assess EPEC and EHEC pathogenicity and tropism.

scholarly journals Type III Secretion-Dependent Sensitivity of Escherichia coli O157 to Specific Ketolides

2015 ◽  
Vol 60 (1) ◽  
pp. 459-470 ◽  
Author(s):  
Romina J. Fernandez-Brando ◽  
Nao Yamaguchi ◽  
Amin Tahoun ◽  
Sean P. McAteer ◽  
Trudi Gillespie ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Type Iii Secretion ◽  
Pathogenic Bacteria ◽  
Bacterial Colonization ◽  
Effector Proteins ◽  
Content Type ◽  
E Coli ◽  
Type Iii ◽  
Bacterial Binding

ABSTRACTA subset of Gram-negative bacterial pathogens uses a type III secretion system (T3SS) to open up a conduit into eukaryotic cells in order to inject effector proteins. These modulate pathways to enhance bacterial colonization. In this study, we screened established bioactive compounds for any that could repress T3SS expression in enterohemorrhagicEscherichia coli(EHEC) O157. The ketolides telithromycin and, subsequently, solithromycin both demonstrated repressive effects on expression of the bacterial T3SS at sub-MICs, leading to significant reductions in bacterial binding and actin-rich pedestal formation on epithelial cells. Preincubation of epithelial cells with solithromycin resulted in significantly less attachment ofE. coliO157. Moreover, bacteria expressing the T3SS were more susceptible to solithromycin, and there was significant preferential killing ofE. coliO157 bacteria when they were added to epithelial cells that had been preexposed to the ketolide. This killing was dependent on expression of the T3SS. Taken together, this research indicates that the ketolide that has accumulated in epithelial cells may traffic back into the bacteria via the T3SS. Considering that neither ketolide induces the SOS response, nontoxic members of this class of antibiotics, such as solithromycin, should be considered for future testing and trials evaluating their use for treatment of EHEC infections. These antibiotics may also have broader significance for treating infections caused by other pathogenic bacteria, including intracellular bacteria, that express a T3SS.

Ex Vivo Inhibition of Platelet Aggregation in Patients with Severe Limb Arteriopathy Treated with BAY U3405, a Specific IX A2 Receptor Antagonist

1994 ◽  
Vol 72 (05) ◽  
pp. 659-662 ◽  
Author(s):  
S Bellucci ◽  
W Kedra ◽  
H Groussin ◽  
N Jaillet ◽  
P Molho-Sabatier ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Ex Vivo ◽  
Randomized Study ◽  
In Vivo Studies ◽  
Walking Distance ◽  
Peripheral Blood Flow ◽  
Walking Ability ◽  
Double Blind ◽  
Platelet Factor

SummaryA double-blind, placebo-controlled randomized study with BAY U3405, a specific thromboxane A2 (TX A2) receptor blocker, was performed in patients suffering from severe stade II limb arteriopathy. BAY U3405 or placebo was administered in 16 patients at 20 mg four times a day (from day 1 to day 3). Hemostatic studies were done before therapy, and on day 2 and day 3 under therapy. On day 3, BAY U3405 was shown to induce a highly statistically significant decrease of the velocity and the intensity of the aggregations mediated by arachidonic acid (56 ± 37% for the velocity, 58 ± 26% for the intensity) or by U46619 endoperoxide analogue (36 ± 35% for the velocity, 37 ± 27% for the intensity). Similar results were already observed on day 2. By contrast, such a decrease was not noticed with ADP mediated platelet aggregation. Furthermore, plasma levels of betathrombo-globulin and platelet factor 4 remained unchanged. Peripheral hemodynamic parameters were also studied. The peripheral blood flow was measured using a Doppler ultrasound; the pain free walking distance and the total walking ability distance were determined under standardized conditions on a treadmill. These last two parameters show a trend to improvement which nevertheless was not statistically significant. All together these results encourage further in vivo studies using BAY U3405 or related compounds on a long-term administration.

Chemical Permeation Enhancers for Transdermal Delivery of Thiocolchicoside: Assessment of Ex-vivo Skin Flux and In-vivo Pharmacokinetics

2017 ◽  
Vol 10 (5) ◽  
pp. 3827-3835
Author(s):  
Y Madhusudan Rao ◽  
Gayatri P ◽  
Ajitha M ◽  
P. Pavan Kumar ◽  
Kiran kumar
Keyword(s):  
Passive Control ◽  
Ex Vivo ◽  
Skin Permeation ◽  
In Vivo Studies ◽  
Permeation Enhancers ◽  
Casting Technique ◽  
Chemical Permeation Enhancers ◽  
Chemical Permeation ◽  
In Vivo Pharmacokinetics

Present investigation comprises the study of ex-vivo skin flux and in-vivo pharmacokinetics of Thiocolchicoside (THC) from transdermal films. The films were fabricated by solvent casting technique employing combination of hydrophilic and hydrophobic polymers. A flux of 18.08 µg/cm2h and 13.37µg/cm2h was achieved for optimized formulations containing 1, 8-cineole and oleic acid respectively as permeation enhancers. The observed flux values were higher when compared to passive control (8.66 µg/cm2h). Highest skin permeation was observed when 1,8-cineole was used as chemical permeation enhancer and it considerably (2-2.5 fold) improved the THC transport across the rat skin. In vivo studies were performed in rabbits and samples were analysed by LC-MS-MS. The mean area under the curve (AUC) values of transdermal film showed about 2.35 times statistically significant (p<0.05) improvement in bioavailability when compared with the oral administration of THC solution. The developed transdermal therapeutic systems using chemical permeation enhancers were suitable for drugs like THC in effective management of muscular pain.    

Monocytes as Carriers of Magnetic Nanoparticles for Tracking Inflammation in the Epileptic Rat Brain

2019 ◽  
Vol 16 (7) ◽  
pp. 637-644 ◽  
Author(s):  
Hadas Han ◽  
Sara Eyal ◽  
Emma Portnoy ◽  
Aniv Mann ◽  
Miriam Shmuel ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Ex Vivo ◽  
In Vivo Studies ◽  
Nanoparticle Distribution ◽  
Spontaneous Seizures ◽  
Systemic Distribution ◽  
Hippocampal Ca1 ◽  
Pilocarpine Model

Background: Inflammation is a hallmark of epileptogenic brain tissue. Previously, we have shown that inflammation in epilepsy can be delineated using systemically-injected fluorescent and magnetite- laden nanoparticles. Suggested mechanisms included distribution of free nanoparticles across a compromised blood-brain barrier or their transfer by monocytes that infiltrate the epileptic brain. Objective: In the current study, we evaluated monocytes as vehicles that deliver nanoparticles into the epileptic brain. We also assessed the effect of epilepsy on the systemic distribution of nanoparticleloaded monocytes. Methods: The in vitro uptake of 300-nm nanoparticles labeled with magnetite and BODIPY (for optical imaging) was evaluated using rat monocytes and fluorescence detection. For in vivo studies we used the rat lithium-pilocarpine model of temporal lobe epilepsy. In vivo nanoparticle distribution was evaluated using immunohistochemistry. Results: 89% of nanoparticle loading into rat monocytes was accomplished within 8 hours, enabling overnight nanoparticle loading ex vivo. The dose-normalized distribution of nanoparticle-loaded monocytes into the hippocampal CA1 and dentate gyrus of rats with spontaneous seizures was 176-fold and 380-fold higher compared to the free nanoparticles (p<0.05). Seizures were associated with greater nanoparticle accumulation within the liver and the spleen (p<0.05). Conclusion: Nanoparticle-loaded monocytes are attracted to epileptogenic brain tissue and may be used for labeling or targeting it, while significantly reducing the systemic dose of potentially toxic compounds. The effect of seizures on monocyte biodistribution should be further explored to better understand the systemic effects of epilepsy.

Phenolic Acids Exert Anticholinesterase and Cognition-Improving Effects

2018 ◽  
Vol 15 (6) ◽  
pp. 531-543 ◽  
Author(s):  
Dominik Szwajgier ◽  
Ewa Baranowska-Wojcik ◽  
Kamila Borowiec
Keyword(s):  
Phenolic Acids ◽  
Ex Vivo ◽  
Amyloid Β ◽  
Inhibitory Effect ◽  
In Vivo Studies ◽  
Amyloid Β Peptide ◽  
Beneficial Effects ◽  
Aβ Fibrils

Numerous authors have provided evidence regarding the beneficial effects of phenolic acids and their derivatives against Alzheimer's disease (AD). In this review, the role of phenolic acids as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) is discussed, including the structure-activity relationship. In addition, the inhibitory effect of phenolic acids on the formation of amyloid β-peptide (Aβ) fibrils is presented. We also cover the in vitro, ex vivo, and in vivo studies concerning the prevention and treatment of the cognitive enhancement.

Development, Pre-clinical Investigation and Histopathological Evaluation of Metronidazole Loaded Topical Formulation for Treatment of Skin Inflammatory disorders

2020 ◽  
Vol 10 ◽  
Author(s):  
Divya Thakur ◽  
Gurpreet Kaur ◽  
Sheetu Wadhwa ◽  
Ashana Puri
Keyword(s):  
Ex Vivo ◽  
Clinical Investigation ◽  
In Vivo Studies ◽  
Tween 20 ◽  
Inflammatory Disorders ◽  
Rat Paw Edema ◽  
Ex Vivo Permeation ◽  
Permeation Studies ◽  
Anti Inflammatory

Background: Metronidazole (MTZ) is an anti-oxidant and anti-inflammatory agent with beneficial therapeutic properties. The hydrophilic nature of molecule limits its penetration across the skin. Existing commercial formulations have limitations of inadequate drug concentration present at target site, which requires frequent administration and poor patient compliance. Objective: The aim of current study was to develop and evaluate water in oil microemulsion of Metronidazole with higher skin retention for treatment of inflammatory skin disorders. Methods: Pseudo ternary phase diagrams were used in order to select the appropriate ratio of surfactant and co-surfactant and identify the microemulsion area. The selected formulation consisted of Capmul MCM as oil, Tween 20 and Span 20 as surfactant and co-surfactant, respectively, and water. The formulation was characterized and evaluated for stability, Ex vivo permeation studies and in vivo anti-inflammatory effect (carrageenan induced rat paw edema, air pouch model), anti-psoriatic activity (mouse-tail test). Results: The particle size analyses revealed average diameter and polydispersity index of selected formulation to be 16 nm and 0.373, respectively. The results of ex vivo permeation studies showed statistically higher mean cumulative amount of MTZ retained in rat skin from microemulsion i.e. 21.90 ± 1.92 μg/cm2 which was 6.65 times higher as compared to Marketed gel (Metrogyl gel®) with 3.29 ± 0.11 μg/cm2 (p<0.05). The results of in vivo studies suggested the microemulsion based formulation of MTZ to be similar in efficacy to Metrogyl gel®. Conclusion: Research suggests efficacy of the developed MTZ loaded microemulsion in treatment of chronic skin inflammatory disorders.

PAF increases vascular permeability without increasing pulmonary arterial pressure in the rat

2001 ◽  
Vol 90 (1) ◽  
pp. 261-268 ◽  
Author(s):  
Leonardo C. Clavijo ◽  
Mary B. Carter ◽  
Paul J. Matheson ◽  
Mark A. Wilson ◽  
William B. Wead ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Pulmonary Edema ◽  
Pulmonary Arterial Pressure ◽  
Ex Vivo ◽  
Platelet Activating Factor ◽  
Microvascular Permeability ◽  
Blue Dye ◽  
E Coli ◽  
Pulmonary Arterial

In vivo pulmonary arterial catheterization was used to determine the mechanism by which platelet-activating factor (PAF) produces pulmonary edema in rats. PAF induces pulmonary edema by increasing pulmonary microvascular permeability (PMP) without changing the pulmonary pressure gradient. Rats were cannulated for measurement of pulmonary arterial pressure (Ppa) and mean arterial pressure. PMP was determined by using either in vivo fluorescent videomicroscopy or the ex vivo Evans blue dye technique. WEB 2086 was administered intravenously (IV) to antagonize specific PAF effects. Three experiments were performed: 1) IV PAF, 2) topical PAF, and 3) Escherichia coli bacteremia. IV PAF induced systemic hypotension with a decrease in Ppa. PMP increased after IV PAF in a dose-related manner. Topical PAF increased PMP but decreased Ppa only at high doses. Both PMP (88 ± 5%) and Ppa (50 ± 3%) increased during E. coli bacteremia. PAF-receptor blockade prevents changes in Ppa and PMP after both topical PAF and E. coli bacteremia. PAF, which has been shown to mediate pulmonary edema in prior studies, appears to act in the lung by primarily increasing microvascular permeability. The presence of PAF might be prerequisite for pulmonary vascular constriction during gram-negative bacteremia.

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