scholarly journals RTX Toxins of Animal Pathogens and Their Role as Antigens in Vaccines and Diagnostics

Toxins ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 719 ◽  
Author(s):  
Joachim Frey
Keyword(s):  
Bacterial Pathogens ◽  
Rtx Toxins ◽  
Animal Pathogens ◽  
Genes Encoding ◽  
Specific Receptors ◽  
Diagnostic Applications ◽  
Β2 Integrins ◽  
Important Marker

Exotoxins play a central role in the pathologies caused by most major bacterial animal pathogens. The large variety of vertebrate and invertebrate hosts in the animal kingdom is reflected by a large variety of bacterial pathogens and toxins. The group of repeats in the structural toxin (RTX) toxins is particularly abundant among bacterial pathogens of animals. Many of these toxins are described as hemolysins due to their capacity to lyse erythrocytes in vitro. Hemolysis by RTX toxins is due to the formation of cation-selective pores in the cell membrane and serves as an important marker for virulence in bacterial diagnostics. However, their physiologic relevant targets are leukocytes expressing β2 integrins, which act as specific receptors for RTX toxins. For various RTX toxins, the binding to the CD18 moiety of β2 integrins has been shown to be host specific, reflecting the molecular basis of the host range of RTX toxins expressed by bacterial pathogens. Due to the key role of RTX toxins in the pathogenesis of many bacteria, antibodies directed against specific RTX toxins protect against disease, hence, making RTX toxins valuable targets in vaccine research and development. Due to their specificity, several structural genes encoding for RTX toxins have proven to be essential in modern diagnostic applications in veterinary medicine.

scholarly journals Arginase Activity in Eisenia andrei Coelomocytes: Function in the Earthworm Innate Response

2021 ◽  
Vol 22 (7) ◽  
pp. 3687
Author(s):  
Joanna Homa ◽  
Alina Klosowska ◽  
Magdalena Chadzinska
Keyword(s):  
Immune Response ◽  
Wound Healing ◽  
Arginase Activity ◽  
Eisenia Andrei ◽  
Heavy Metals Ions ◽  
First Time ◽  
Important Marker

Arginase is the manganese metalloenzyme catalyzing the conversion of l-arginine to l-ornithine and urea. In vertebrates, arginase is involved in the immune response, tissue regeneration, and wound healing and is an important marker of alternative anti-inflammatory polarization of macrophages. In invertebrates, data concerning the role of arginase in these processes are very limited. Therefore, in the present study, we focused on the changes in arginase activity in the coelomocytes of Eisenia andrei. We studied the effects of lipopolysaccharide (LPS), hydrogen peroxide (H2O2), heavy metals ions (e.g., Mn2+), parasite infection, wound healing, and short-term fasting (5 days) on arginase activity. For the first time in earthworms, we described arginase activity in the coelomocytes and found that it can be up-regulated upon in vitro stimulation with LPS and H2O2 and in the presence of Mn2+ ions. Moreover, arginase activity was also up-regulated in animals in vivo infected with nematodes or experiencing segment amputation, but not in fasting earthworms. Furthermore, we confirmed that the activity of coelomocyte arginase can be suppressed by l-norvaline. Our studies strongly suggest that similarly to the vertebrates, also in the earthworms, coelomocyte arginase is an important element of the immune response and wound healing processes.

scholarly journals Profiling of H3K27Ac Reveals the Influence of Asthma on the Epigenome of the Airway Epithelium

2020 ◽  
Vol 11 ◽  
Author(s):  
Peter McErlean ◽  
Audrey Kelly ◽  
Jaideep Dhariwal ◽  
Max Kirtland ◽  
Julie Watson ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Airway Disease ◽  
Small Pilot Study ◽  
Guide Rnas ◽  
Environmental Interactions ◽  
Genome Wide ◽  
Genes Encoding ◽  
Chronic Airway Disease

BackgroundAsthma is a chronic airway disease driven by complex genetic–environmental interactions. The role of epigenetic modifications in bronchial epithelial cells (BECs) in asthma is poorly understood.MethodsWe piloted genome-wide profiling of the enhancer-associated histone modification H3K27ac in BECs from people with asthma (n = 4) and healthy controls (n = 3).ResultsWe identified n = 4,321 (FDR < 0.05) regions exhibiting differential H3K27ac enrichment between asthma and health, clustering at genes associated predominately with epithelial processes (EMT). We identified initial evidence of asthma-associated Super-Enhancers encompassing genes encoding transcription factors (TP63) and enzymes regulating lipid metabolism (PTGS1). We integrated published datasets to identify epithelium-specific transcription factors associated with H3K27ac in asthma (TP73) and identify initial relationships between asthma-associated changes in H3K27ac and transcriptional profiles. Finally, we investigated the potential of CRISPR-based approaches to functionally evaluate H3K27ac-asthma landscape in vitro by identifying guide-RNAs capable of targeting acetylation to asthma DERs and inducing gene expression (TLR3).ConclusionOur small pilot study validates genome-wide approaches for deciphering epigenetic mechanisms underlying asthma pathogenesis in the airways.

scholarly journals Bacterial Pathogens Induce Abscess Formation by CD4+ T-Cell Activation via the CD28–B7-2 Costimulatory Pathway

2000 ◽  
Vol 68 (12) ◽  
pp. 6650-6655 ◽  
Author(s):  
Arthur O. Tzianabos ◽  
Anil Chandraker ◽  
Wiltrud Kalka-Moll ◽  
Francesca Stingele ◽  
Victor M. Dong ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Pathogenic Bacteria ◽  
Cell Activation ◽  
Bacterial Pathogens ◽  
Abscess Formation

ABSTRACT Abscesses are a classic host response to infection by many pathogenic bacteria. The immunopathogenesis of this tissue response to infection has not been fully elucidated. Previous studies have suggested that T cells are involved in the pathologic process, but the role of these cells remains unclear. To delineate the mechanism by which T cells mediate abscess formation associated with intra-abdominal sepsis, the role of T-cell activation and the contribution of antigen-presenting cells via CD28-B7 costimulation were investigated. T cells activated in vitro by zwitterionic bacterial polysaccharides (Zps) known to induce abscess formation required CD28-B7 costimulation and, when adoptively transferred to the peritoneal cavity of naı̈ve rats, promoted abscess formation. Blockade of T-cell activation via the CD28-B7 pathway in animals with CTLA4Ig prevented abscess formation following challenge with different bacterial pathogens, including Staphylococcus aureus,Bacteroides fragilis, and a combination ofEnterococcus faecium and Bacteroides distasonis. In contrast, these animals had an increased abscess rate following in vivo T-cell activation via CD28 signaling. Abscess formation in vivo and T-cell activation in vitro required costimulation by B7-2 but not B7-1. These results demonstrate that abscess formation by pathogenic bacteria is under the control of a common effector mechanism that requires T-cell activation via the CD28–B7-2 pathway.

scholarly journals Exploration of bacterial bottlenecks and Streptococcus pneumoniae pathogenesis by CRISPRi-seq

2020 ◽  
Author(s):  
Xue Liu ◽  
Jacqueline M. Kimmey ◽  
Vincent de Bakker ◽  
Victor Nizet ◽  
Jan-Willem Veening
Keyword(s):  
Streptococcus Pneumoniae ◽  
Post Infection ◽  
Systemic Infection ◽  
The Body ◽  
Genetic Screens ◽  
Animal Pathogens ◽  
Genes Encoding ◽  
One Step

AbstractStreptococcus pneumoniae is a commensal bacterium of the human nasopharynx, but can cause harmful infections if it spreads to other parts of the body, such as pneumonia, sepsis or meningitis. To facilitate pathogenesis studies, we constructed a doxycycline-inducible pooled CRISPR interference (CRISPRi) library targeting all operons in protypical S. pneumoniae strain D39V. Our library design allows fitness within the pool to be assessed by a one-step PCR reaction directly followed by Illumina sequencing (CRISPRi-seq). The doxycycline-inducible CRISPRi system is tightly controllable and suitable for both bottleneck exploration and evaluation of gene fitness in vitro and in vivo. Here, we applied CRISPRi-seq to identify genetic factors important for causing pneumococcal pneumonia. Mice were infected intratracheally with our CRISPRi library and bacteria collected at 24 h (from lung) and 48 h (from both lung and blood) post-infection. CRISPRi-seq showed a critical bottleneck at 48 h after intratracheal infection, with only a few bacteria surviving the brunt of the innate immune response to cause systemic infection. However, earlier at 24 h post-infection, many significant differences in gene fitness cost between in vitro and in vivo conditions were identified, including genes encoding known and putative novel virulence factors, genes essential only in vivo, and genes essential only in vitro. A key advantage of CRISPRi-seq over traditional transposon-based genetic screens is that all genes, including essential genes, can be tested for their role in virulence and pathogenicity. The approaches developed here should be generally applicable to study infection bottlenecks and in vivo fitness for other important human and animal pathogens.

scholarly journals Role of β2-integrins for homing and neovascularization capacity of endothelial progenitor cells

2004 ◽  
Vol 201 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Emmanouil Chavakis ◽  
Alexandra Aicher ◽  
Christopher Heeschen ◽  
Ken-ichiro Sasaki ◽  
Ralf Kaiser ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Endothelial Progenitor Cells ◽  
Ex Vivo ◽  
Limb Ischemia ◽  
Endothelial Progenitor ◽  
Cell Monolayers ◽  
Β2 Integrins

The mechanisms of homing of endothelial progenitor cells (EPCs) to sites of ischemia are unclear. Here, we demonstrate that ex vivo–expanded EPCs as well as murine hematopoietic Sca-1+/Lin− progenitor cells express β2-integrins, which mediate the adhesion of EPCs to endothelial cell monolayers and their chemokine-induced transendothelial migration in vitro. In a murine model of hind limb ischemia, Sca-1+/Lin− hematopoietic progenitor cells from β2-integrin–deficient mice are less capable of homing to sites of ischemia and of improving neovascularization. Preactivation of the β2-integrins expressed on EPCs by activating antibodies augments the EPC-induced neovascularization in vivo. These results provide evidence for a novel function of β2-integrins in postnatal vasculogenesis.

scholarly journals RhoGDIα-dependent balance between RhoA and RhoC is a key regulator of cancer cell tumorigenesis

2011 ◽  
Vol 22 (17) ◽  
pp. 3263-3275 ◽  
Author(s):  
T. T. Giang Ho ◽  
Audrey Stultiens ◽  
Johanne Dubail ◽  
Charles M. Lapière ◽  
Betty V. Nusgens ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Cancer Progression ◽  
Dynamic Balance ◽  
Cellular Functions ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Interfering Rna

RhoGTPases are key signaling molecules regulating main cellular functions such as migration, proliferation, survival, and gene expression through interactions with various effectors. Within the RhoA-related subclass, RhoA and RhoC contribute to several steps of tumor growth, and the regulation of their expression affects cancer progression. Our aim is to investigate their respective contributions to the acquisition of an invasive phenotype by using models of reduced or forced expression. The silencing of RhoC, but not of RhoA, increased the expression of genes encoding tumor suppressors, such as nonsteroidal anti-inflammatory drug–activated gene 1 (NAG-1), and decreased migration and the anchorage-independent growth in vitro. In vivo, RhoC small interfering RNA (siRhoC) impaired tumor growth. Of interest, the simultaneous knockdown of RhoC and NAG-1 repressed most of the siRhoC-related effects, demonstrating the central role of NAG-1. In addition of being induced by RhoC silencing, NAG-1 was also largely up-regulated in cells overexpressing RhoA. The silencing of RhoGDP dissociation inhibitor α (RhoGDIα) and the overexpression of a RhoA mutant unable to bind RhoGDIα suggested that the effect of RhoC silencing is indirect and results from the up-regulation of the RhoA level through competition for RhoGDIα. This study demonstrates the dynamic balance inside the RhoGTPase network and illustrates its biological relevance in cancer progression.

scholarly journals The Rice Tungro Bacilliform Virus Gene II Product Interacts with the Coat Protein Domain of the Viral Gene III Polyprotein

2000 ◽  
Vol 74 (5) ◽  
pp. 2073-2083 ◽  
Author(s):  
Etienne Herzog ◽  
Orlene Guerra-Peraza ◽  
Thomas Hohn
Keyword(s):  
Coat Protein ◽  
Protein Domain ◽  
Rice Tungro Bacilliform Virus ◽  
Viral Gene ◽  
Yeast Two Hybrid ◽  
Yeast Two Hybrid System ◽  
Genes Encoding ◽  
Two Hybrid

ABSTRACT Rice tungro bacilliform virus (RTBV) is a plant pararetrovirus whose DNA genome contains four genes encoding three proteins and a large polyprotein. The function of most of the viral proteins is still unknown. To investigate the role of the gene II product (P2), we searched for interactions between this protein and other RTBV proteins. P2 was shown to interact with the coat protein (CP) domain of the viral gene III polyprotein (P3) both in the yeast two-hybrid system and in vitro. Domains involved in the P2-CP association have been identified and mapped on both proteins. To determine the importance of this interaction for viral multiplication, the infectivity of RTBV gene II mutants was investigated by agroinoculation of rice plants. The results showed that virus viability correlates with the ability of P2 to interact with the CP domain of P3. This study suggests that P2 could participate in RTBV capsid assembly.

scholarly journals ERK1/2 mediates glucose-regulated POMC gene expression in hypothalamic neurons

2015 ◽  
Vol 54 (2) ◽  
pp. 125-135 ◽  
Author(s):  
Juan Zhang ◽  
Yunting Zhou ◽  
Cheng Chen ◽  
Feiyuan Yu ◽  
Yun Wang ◽  
...  
Keyword(s):  
Specific Inhibitor ◽  
Neuronal Cell ◽  
Glucose Sensing ◽  
Hypothalamic Neurons ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Low Glucose ◽  
Amp Activated Protein Kinase

Hypothalamic glucose-sensing neurons regulate the expression of genes encoding feeding-related neuropetides POMC, AgRP, and NPY – the key components governing metabolic homeostasis. AMP-activated protein kinase (AMPK) is postulated to be the molecular mediator relaying glucose signals to regulate the expression of these neuropeptides. Whether other signaling mediator(s) plays a role is not clear. In this study, we investigated the role of ERK1/2 using primary hypothalamic neurons as the model system. The primary neurons were differentiated from hypothalamic progenitor cells. The differentiated neurons possessed the characteristic neuronal cell morphology and expressed neuronal post-mitotic markers as well as leptin-regulated orexigenic POMC and anorexigenic AgRP/NPY genes. Treatment of cells with glucose dose-dependently increased POMC and decreased AgRP/NPY expression with a concurrent suppression of AMPK phosphorylation. In addition, glucose treatment dose-dependently increased the ERK1/2 phosphorylation. Blockade of ERK1/2 activity with its specific inhibitor PD98059 partially (approximately 50%) abolished glucose-induced POMC expression, but had little effect on AgRP/NPY expression. Conversely, blockade of AMPK activity with its specific inhibitor produced a partial (approximately 50%) reversion of low-glucose-suppressed POMC expression, but almost completely blunted the low-glucose-induced AgRP/NPY expression. The results indicate that ERK1/2 mediated POMC but not AgRP/NPY expression. Confirming the in vitro findings, i.c.v. administration of PD98059 in rats similarly attenuated glucose-induced POMC expression in the hypothalamus, but again had little effect on AgRP/NPY expression. The results are indicative of a novel role of ERK1/2 in glucose-regulated POMC expression and offer new mechanistic insights into hypothalamic glucose sensing.

Angiotensin II binding sites in aortic endothelium of domestic fowl

1990 ◽  
Vol 258 (3) ◽  
pp. R777-R782 ◽  
Author(s):  
J. N. Stallone ◽  
H. Nishimura ◽  
A. Nasjletti
Keyword(s):  
Angiotensin Ii ◽  
Domestic Fowl ◽  
Angiotensin Receptors ◽  
Ang Ii ◽  
Aortic Endothelium ◽  
Specific Receptors ◽  
Layer Chromatography

In domestic fowl, angiotensin II (ANG II) produces a unique vasodepressor response in vivo and endothelium-dependent relaxation of aortic rings in vitro that appear to be a direct effect on vascular smooth muscle mediated through vascular angiotensin receptors. To explore the possible role of the endothelium in ANG II-induced vasodilation, ANG II binding to aortic membrane fractions and intact endothelium and prostaglandin (PG) production were examined in fowl aortas. 125I-[Ile5]ANG II binding by endothelium-intact aortic membrane fractions was consistently higher than binding by identically prepared endothelium-deleted membrane fractions at virtually all concentrations of ligand (10 pM-0.20 microM). Incubation of intact aortic rings with 125I-[Ile5]ANG II (0.50 nM) resulted in specific endothelial binding that increased linearly with time from 5.5 +/- 1.7 (SE) fmol/mg protein at 5 min to 13.7 +/- 1.8 at 30 min. Endothelial ANG II binding increased linearly with the dose of ligand, from 2.7 +/- 0.3 fmol/mg protein at 0.1 nM to 21.0 +/- 2.2 at 1.0 nM. Specific ANG II binding to aortic endothelium was competitively displaced 73 +/- 11% by unlabeled ANG II (0.1 microM) but not by bradykinin (0.1 microM). Incubation of intact aortic rings with [14C]arachidonic acid resulted in the formation of radioactive metabolites that comigrated in thin-layer chromatography with authentic PGE2 but not with 6-keto-PGF1 alpha. PGE2 production by aortic rings (44.4 +/- 4.5 ng.mg dry tissue-1.h-1) was not stimulated by addition of ANG II. These results suggest that specific receptors for ANG II exist in fowl aortic endothelium and that PGs are not involved in ANG II-induced vasodilation of the fowl aorta.

scholarly journals Sex difference in the mouse BAT transcriptome reveals a role of progesterone

2020 ◽  
Author(s):  
Kasiphak Kaikaew ◽  
Aldo Grefhorst ◽  
Jacobie Steenbergen ◽  
Sigrid M.a. Swagemakers ◽  
Anke McLuskey ◽  
...  
Keyword(s):  
Differential Expression ◽  
Molecular Mechanisms ◽  
Gonadal Hormones ◽  
Cell Contact ◽  
Differential Expression Pattern ◽  
Brown Adipose ◽  
Transcriptional Pattern ◽  
Genes Encoding

Brown adipose tissue (BAT) is a metabolically active organ that exhibits sex-differential features, i.e., being generally more abundant and active in females than in males. Although sex steroids, particularly estrogens, have been shown to regulate BAT thermogenic function, the underlying molecular mechanisms contributing to sexual dimorphism in basal BAT activity have not been elucidated. Therefore, we assessed the transcriptome of interscapular BAT of male and female C57BL/6J mice by RNA sequencing and identified 295 genes showing ≥2-fold differential expression (adjusted P<0.05). In silico functional annotation clustering suggested an enrichment of genes encoding proteins involved in cell-cell contact, interaction, and adhesion. Ovariectomy reduced the expression of these genes in female BAT towards a male pattern whereas orchiectomy had marginal effects on the transcriptional pattern, indicating a prominent role of female gonadal hormones in this sex-differential expression pattern. Progesterone was identified as a possible upstream regulator of the sex-differentially expressed genes. Studying direct effects of progesterone in vitro in primary adipocytes showed that progesterone significantly altered the transcription of several of the identified genes, possibly via the glucocorticoid receptor. In conclusion, this study reveals a sexually dimorphic transcription profile in murine BAT at general housing conditions and demonstrates a role for progesterone in the regulation of the interscapular BAT transcriptome.

Sign in / Sign up

Export Citation Format

Share Document