scholarly journals Modelling of Infection by Enteropathogenic Escherichia coli Strains in Lineages 2 and 4 Ex Vivo and In Vivo by Using Citrobacter rodentium Expressing TccP

2009 ◽  
Vol 77 (4) ◽  
pp. 1304-1314 ◽  
Author(s):  
Francis Girard ◽  
Valérie F. Crepin ◽  
Gad Frankel
Keyword(s):  
Escherichia Coli ◽  
Actin Polymerization ◽  
Ex Vivo ◽  
In Vivo Studies ◽  
Citrobacter Rodentium ◽  
T3ss Effector ◽  
Gut Mucosa ◽  
Colonization Dynamics

ABSTRACT Enteropathogenic Escherichia coli (EPEC) strains colonize the human gut mucosa via attaching-and-effacing (A/E) lesion formation, while in vitro they employ diverse strategies to trigger actin polymerization. Strains belonging to the EPEC-1 lineage trigger strong actin polymerization via tyrosine phosphorylation of the type III secretion system (T3SS) effector Tir, recruitment of Nck, and activation of N-WASP. Strains belonging to EPEC-2 and EPEC-4 can trigger strong actin polymerization by dual mechanisms, since while employing the Tir-Nck pathway they can additionally activate N-WASP via the T3SS effectors TccP2 and TccP, respectively. It is currently not known if the ability to trigger actin polymerization by twin mechanisms increases in vivo virulence or fitness. Since mice are resistant to EPEC infection, in vivo studies are frequently done using the murine model pathogen Citrobacter rodentium, which shares with EPEC-1 strains the ability to induce A/E lesions and trigger strong actin polymerization via the Tir:Nck pathway. In order to model infections with EPEC-2 and EPEC-4, we constructed C. rodentium strains expressing TccP. Using a mouse intestinal in vitro organ culture model and oral gavage into C57BL/6 mice, we have shown that TccP can cooperate with Tir of C. rodentium. The recombinant strains induced typical A/E lesions ex vivo and in vivo. Expression of TccP did not alter C. rodentium colonization dynamics or pathology. In competition with the wild-type strain, expression of TccP in C. rodentium did not confer a competitive advantage.

scholarly journals Cortactin Recruitment by Enterohemorrhagic Escherichia coli O157:H7 during Infection In Vitro and Ex Vivo

2008 ◽  
Vol 76 (10) ◽  
pp. 4669-4676 ◽  
Author(s):  
Aurelie Mousnier ◽  
Andrew D. Whale ◽  
Stephanie Schüller ◽  
John M. Leong ◽  
Alan D. Phillips ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Actin Polymerization ◽  
Cultured Cells ◽  
Ex Vivo ◽  
Enterohemorrhagic Escherichia Coli ◽  
T3ss Effector ◽  
Mucosal Surfaces ◽  
N Terminus

ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is an important human pathogen that colonizes the gut mucosa via attaching and effacing (A/E) lesions; A/E lesion formation in vivo and ex vivo is dependent on the type III secretion system (T3SS) effector Tir. Infection of cultured cells by EHEC leads to induction of localized actin polymerization, which is dependent on Tir and a second T3SS effector protein, TccP, also known as EspFU. Recently, cortactin was shown to bind both the N terminus of Tir and TccP via its SH3 domain and to play a role in EHEC-triggered actin polymerization in vitro. In this study, we investigated the recruitment of cortactin to the site of EHEC adhesion during infection of in vitro-cultured cells and mucosal surfaces ex vivo (using human terminal ileal in vitro organ cultures [IVOC]). We have shown that cortactin is recruited to the site of EHEC adhesion in vitro downstream of TccP and N-WASP. Deletion of the entire N terminus of Tir or replacing the N-terminal polyproline region with alanines did not abrogate actin polymerization or cortactin recruitment. In contrast, recruitment of cortactin to the site of EHEC adhesion in IVOC is TccP independent. These results imply that cortactin is recruited to the site of EHEC adhesion in vitro and ex vivo by different mechanisms and suggest that cortactin might have a role during EHEC infection of mucosal surfaces.

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.

Pharmacokinetic and toxicology assessment of INTERCEPT (S-59 and UVA treated) platelets

2001 ◽  
Vol 20 (10) ◽  
pp. 533-550 ◽  
Author(s):  
V Ciaravino ◽  
T McCullough ◽  
A D Dayan
Keyword(s):  
Ex Vivo ◽  
Reproductive Toxicity ◽  
In Vivo Studies ◽  
Pathogen Inactivation ◽  
Platelet Concentrates ◽  
Baxter Healthcare ◽  
Safety Margins ◽  
Toxicology Assessment

The pathogen inactivation process developed by Cerus and Baxter Healthcare Corporations uses the psoralen, S-59 (amotosalen) in an ex vivo photochemical treatment (PCT) process to inactivate viruses, bacteria, protozoans, and leukocytes in platelet concentrates and plasma. Studies were performed by intravenous infusion of S-59 PCT formulations-compound adsorption device (CAD) treatment and with non-UVA illuminated S-59, using doses that were multiples of potential clinical exposures. The studies comprised full pharmacokinetic, single and repeated-dose (up to 13 weeks duration) toxicity, safety pharmacology (CNS, renal, and cardiovascular), reproductive toxicity, genotoxicity, carcinogenicity testing in the p53- mouse, vein irritation, and phototoxicity. No specific target organ toxicity (clinical or histopathological), reproductive toxicity, or carcinogenicity was observed. S-59 and/or PCT formulations demonstrated CNS, ECG, and phototoxicity only at supraclinical doses. Based on the extremely large safety margins (>30,000 fold expected clinical exposures), the CNS and ECG observations are not considered to have any toxicological relevance. Additionally, after a complete assessment, mutagenicity and phototoxicity results are not considered relevant for the proposed use of INTERCEPT platelets. Thus, the results of an extensive series of in vitro and in vivo studies have not demonstrated any toxicologically relevant effects of platelet concentrates prepared by the INTERCEPT system.

scholarly journals The pathophysiologic role of the protein kinase Cδ pathway in the intervertebral discs of rabbits and mice: In vitro, ex vivo, and in vivo studies

2012 ◽  
Vol 64 (6) ◽  
pp. 1950-1959 ◽  
Author(s):  
Michael B. Ellman ◽  
Jae-Sung Kim ◽  
Howard S. An ◽  
Jeffrey S. Kroin ◽  
Xin Li ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Ex Vivo ◽  
Intervertebral Discs ◽  
In Vivo Studies ◽  
Protein Kinase Cδ

Ex vivo-expanded bone marrow CD34+ for acute myocardial infarction treatment: in vitro and in vivo studies

Cytotherapy ◽  
2011 ◽  
Vol 13 (9) ◽  
pp. 1140-1152 ◽  
Author(s):  
Monica Gunetti ◽  
Alessio Noghero ◽  
Fabiola Molla ◽  
Lidia Irene Staszewsky ◽  
Noeleen de Angelis ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Bone Marrow ◽  
Ex Vivo ◽  
In Vivo Studies

311 EX VIVO-EXPANDED PERIPHERAL CD34+ CELLS FOR CHRONICALLY INJURED LIVER TREATMENT: IN VITRO AND IN VIVO STUDIES

2013 ◽  
Vol 58 ◽  
pp. S130-S131
Author(s):  
T. Nakamura ◽  
T. Torimura ◽  
H. Masuda ◽  
H. Iwamoto ◽  
O. Hashimoto ◽  
...  
Keyword(s):  
Ex Vivo ◽  
In Vivo Studies ◽  
Cd34 Cells ◽  
Injured Liver

scholarly journals Interaction of Enteropathogenic and Shiga Toxin-Producing Escherichia coli and Porcine Intestinal Mucosa: Role of Intimin and Tir in Adherence

2005 ◽  
Vol 73 (9) ◽  
pp. 6005-6016 ◽  
Author(s):  
Francis Girard ◽  
Isabelle Batisson ◽  
Gad M. Frankel ◽  
Josée Harel ◽  
John M. Fairbrother
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Actin Polymerization ◽  
Animal Species ◽  
Ex Vivo ◽  
Epec Strain ◽  
E Coli ◽  
In Vitro Organ Culture

ABSTRACT The ileal in vitro organ culture (IVOC) model using tissues originating from colostrum-deprived newborn piglets has proven to be an effective way to study the attaching and effacing (A/E) phenotype of porcine enteropathogenic Escherichia coli (EPEC) ex vivo. The aim of this study was to investigate the role of intimin subtype and Tir in the adherence of EPEC and Shiga-toxin-producing E. coli (STEC), isolated from different animal species, to porcine intestinal IVOC. Moreover, the role of intimin in Tir-independent adherence of the human EPEC strain E2348/69 was investigated using intimin and Tir-deficient derivatives. Our results demonstrated that A/E E. coli strains (AEEC) from various animal species and humans induce the A/E phenotype in porcine ileal IVOC and that intimin subtype influences intestinal adherence and tropism of AEEC strains. We also showed that a tir mutant of EPEC strain E2348/69 demonstrates close adherence to the epithelial cells of porcine ileal IVOC segments, with microvillous effacement but with no evidence of actin polymerization or pedestal formation, and that intimin seems to be involved in this phenotype. Overall, this study provides further evidence for the existence of one or more host-cell-encoded intimin receptor(s) in the pig gut.

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