scholarly journals Biosensors for the Detection of Interaction between Legionella pneumophila Collagen-Like Protein and Glycosaminoglycans

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2668 ◽  
Author(s):  
Han Su ◽  
Shaopei Li ◽  
Mauricio Terebiznik ◽  
Cyril Guyard ◽  
Kagan Kerman
Keyword(s):  
Legionella Pneumophila ◽  
Dermatan Sulfate ◽  
Electrochemical Impedance ◽  
Host Cells ◽  
High Affinity ◽  
Extracellular Matrix Components ◽  
Biophysical Studies ◽  
Ligand Interactions ◽  
Matrix Components ◽  
Chondroitin Sulfate A

The adhesin Legionella collagen-like (Lcl) protein can bind to extracellular matrix components and mediate the binding of Legionella pneumophila to host cells. In this study, electrochemical impedance spectroscopy (EIS) and surface plasmon resonance (SPR)-based biosensors were employed to characterize these interactions between glycosaminoglycans (GAGs) and the adhesin Lcl protein. Fucoidan displayed a high affinity (KD 18 nM) for Lcl protein. Chondroitin sulfate A and dermatan sulfate differ in the position of a carboxyl group replacing D-glucuronate with D-iduronate. Our results indicated that the presence of D-iduronate in dermatan sulfate strongly hindered its interaction with Lcl. These biophysical studies provided valuable information in our understanding of adhesin-ligand interactions related to Legionella pneumophila infections.

scholarly journals Heparin modulates the organization of hydrated collagen gels and inhibits gel contraction by fibroblasts

1987 ◽  
Vol 104 (4) ◽  
pp. 1097-1103 ◽  
Author(s):  
C Guidry ◽  
F Grinnell
Keyword(s):  
Extracellular Matrix ◽  
Hyaluronic Acid ◽  
Dermatan Sulfate ◽  
Amorphous Material ◽  
Collagen Fibrils ◽  
The Other ◽  
Mechanical Forces ◽  
Collagen Gels ◽  
Extracellular Matrix Components ◽  
Matrix Components

We studied the effects of extracellular matrix components on fibroblast contraction of hydrated collagen gels. After 4-h incubations, heparin-containing collagen gels contracted only 10% compared with 50% contraction of control gels. Contraction was not affected by hyaluronic acid, dermatan sulfate, or fibronectin, implying that the activity of heparin was specific. The possibility that heparin inhibited attachment of the cells to the gels was ruled out. Also, addition of heparin to the incubation medium had no effect on contraction. Microscopic examination showed that control collagen gels were composed of a uniform network of interlocking fibrils of similar sizes. Heparin-containing gels, on the other hand, were highly variable with some collagen bundles containing 5-6 collagen fibrils and other regions containing amorphous material. Unlike the control gels, the fibrils of heparin-containing gels were not continuously interconnected. Based on the results, we propose that fibroblasts attach normally to the collagen fibrils of heparin-containing gels and attempt to contract the gels, but the mechanical forces exerted by fibroblasts on individual collagen fibrils cannot be propagated throughout the gels.

scholarly journals Anti-Fibrotic Activity of an Antimicrobial Peptide in a Drosophila Model

2021 ◽  
pp. 1-15
Author(s):  
Dilan Khalili ◽  
Christina Kalcher ◽  
Stefan Baumgartner ◽  
Ulrich Theopold
Keyword(s):  
Antimicrobial Peptide ◽  
Cell Polarity ◽  
Active Form ◽  
Ectopic Expression ◽  
Secretory Activity ◽  
Ras Oncogene ◽  
Apicobasal Polarity ◽  
Pathological Conditions ◽  
Extracellular Matrix Components ◽  
Matrix Components

Fibrotic lesions accompany several pathological conditions, including tumors. We show that expression of a dominant-active form of the Ras oncogene in <i>Drosophila</i> salivary glands (SGs) leads to redistribution of components of the basement membrane (BM) and fibrotic lesions. Similar to several types of mammalian fibrosis, the disturbed BM attracts clot components, including insect transglutaminase and phenoloxidase. SG epithelial cells show reduced apicobasal polarity accompanied by a loss of secretory activity. Both the fibrotic lesions and the reduced cell polarity are alleviated by ectopic expression of the antimicrobial peptide drosomycin (Drs), which also restores the secretory activity of the SGs. In addition to extracellular matrix components, both Drs and F-actin localize to fibrotic lesions.

scholarly journals Legionella pneumophila DotU and IcmF Are Required for Stability of the Dot/Icm Complex

2004 ◽  
Vol 72 (10) ◽  
pp. 5983-5992 ◽  
Author(s):  
Jessica A. Sexton ◽  
Jennifer L. Miller ◽  
Aki Yoneda ◽  
Thomas E. Kehl-Fie ◽  
Joseph P. Vogel
Keyword(s):  
Cell Surface ◽  
Legionella Pneumophila ◽  
Bacterial Species ◽  
Wide Distribution ◽  
Host Cells ◽  
Growth Defect ◽  
Intracellular Growth ◽  
Homologous Proteins ◽  
Type Iv ◽  
Cell Surface Structure

ABSTRACT Legionella pneumophila utilizes a type IV secretion system (T4SS) encoded by 26 dot/icm genes to replicate inside host cells and cause disease. In contrast to all other L. pneumophila dot/icm genes, dotU and icmF have homologs in a wide variety of gram-negative bacteria, none of which possess a T4SS. Instead, dotU and icmF orthologs are linked to a locus encoding a conserved cluster of proteins designated IcmF-associated homologous proteins, which has been proposed to constitute a novel cell surface structure. We show here that dotU is partially required for L. pneumophila intracellular growth, similar to the known requirement for icmF. In addition, we show that dotU and icmF are necessary for optimal plasmid transfer and sodium sensitivity, two additional phenotypes associated with a functional Dot/Icm complex. We found that these effects are due to the destabilization of the T4SS at the transition into the stationary phase, the point at which L. pneumophila becomes virulent. Specifically, three Dot proteins (DotH, DotG, and DotF) exhibit decreased stability in a ΔdotU ΔicmF strain. Furthermore, overexpression of just one of these proteins, DotH, is sufficient to suppress the intracellular growth defect of the ΔdotU ΔicmF mutant. This suggests a model where the DotU and IcmF proteins serve to prevent DotH degradation and therefore function to stabilize the L. pneumophila T4SS. Due to their wide distribution among bacterial species and their genetic linkage to known or predicted cell surface structures, we propose that this function in complex stabilization may be broadly conserved.

scholarly journals Age related extracellular matrix and interstitial cell phenotype in pulmonary valves

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Shaohua Wu ◽  
Vikas Kumar ◽  
Peng Xiao ◽  
Mitchell Kuss ◽  
Jung Yul Lim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Extracellular Matrix ◽  
Heart Valve ◽  
Cell Phenotype ◽  
Primary Concern ◽  
Ross Operation ◽  
Age Related ◽  
Cardiovascular Morbidity And Mortality ◽  
Extracellular Matrix Components ◽  
Matrix Components

AbstractHeart valve disease is a common manifestation of cardiovascular disease and is a significant cause of cardiovascular morbidity and mortality worldwide. The pulmonary valve (PV) is of primary concern because of its involvement in common congenital heart defects, and the PV is usually the site for prosthetic replacement following a Ross operation. Although effects of age on valve matrix components and mechanical properties for aortic and mitral valves have been studied, very little is known about the age-related alterations that occur in the PV. In this study, we isolated PV leaflets from porcine hearts in different age groups (~ 4–6 months, denoted as young versus ~ 2 years, denoted as adult) and studied the effects of age on PV leaflet thickness, extracellular matrix components, and mechanical properties. We also conducted proteomics and RNA sequencing to investigate the global changes of PV leaflets and passage zero PV interstitial cells in their protein and gene levels. We found that the size, thickness, elastic modulus, and ultimate stress in both the radial and circumferential directions and the collagen of PV leaflets increased from young to adult age, while the ultimate strain and amount of glycosaminoglycans decreased when age increased. Young and adult PV had both similar and distinct protein and gene expression patterns that are related to their inherent physiological properties. These findings are important for us to better understand the physiological microenvironments of PV leaflet and valve cells for correctively engineering age-specific heart valve tissues.

scholarly journals Subinhibitory Concentrations of Antimicrobial Agents Reduce the Uptake of Legionella pneumophila into Acanthamoeba castellanii and U937 Cells by Altering the Expression of Virulence-Associated Antigens

1998 ◽  
Vol 42 (11) ◽  
pp. 2870-2876 ◽  
Author(s):  
P. Christian Lück ◽  
Jürgen W. Schmitt ◽  
Arne Hengerer ◽  
Jürgen H. Helbig
Keyword(s):  
Monoclonal Antibodies ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Legionella Pneumophila ◽  
Antimicrobial Agents ◽  
Acanthamoeba Castellanii ◽  
Host Cells ◽  
Uncharacterized Protein ◽  
Subinhibitory Concentrations

ABSTRACT We determined the MICs of ampicillin, ciprofloxacin, erythromycin, imipenem, and rifampin for two clinical isolates of Legionella pneumophila serogroup 1 by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay and by quantitative culture. To test the influence of subinhibitory concentrations (sub-MICs) of antimicrobial agents on Legionella uptake into Acanthamoeba castellanii and U937 macrophage-like cells, both strains were pretreated with 0.25 MICs of the antibiotics for 24 h. In comparison to that for the untreated control, subinhibitory concentrations of antibiotics significantly reducedLegionella uptake into the host cells. Measurement of the binding of monoclonal antibodies against several Legionellaantigens by enzyme-linked immunoassays indicated that sub-MIC antibiotic treatment reduced the expression of the macrophage infectivity potentiator protein (Mip), the Hsp 60 protein, the outer membrane protein (OmpM), an as-yet-uncharacterized protein of 55 kDa, and a few lipopolysaccharide (LPS) epitopes. In contrast, the expression of some LPS epitopes recognized by monoclonal antibodies 8/5 and 30/4 as well as a 45-kDa protein, a 58-kDa protein, and the major outer membrane protein (OmpS) remained unaffected.

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