scholarly journals Salmonella Extracellular Matrix Components Influence Biofilm Formation and Gallbladder Colonization

2016 ◽  
Vol 84 (11) ◽  
pp. 3243-3251 ◽  
Author(s):  
Haley E. Adcox ◽  
Erin M. Vasicek ◽  
Varun Dwivedi ◽  
Ky V. Hoang ◽  
Joanne Turner ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Typhoid Fever ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Bacterial Survival ◽  
Content Type ◽  
Extracellular Matrix Components ◽  
Matrix Components

Salmonella enterica serovar Typhi, the causative agent of typhoid fever in humans, forms biofilms encapsulated by an extracellular matrix (ECM). Biofilms facilitate colonization and persistent infection in gallbladders of humans and mouse models of chronic carriage. Individual roles of matrix components have not been completely elucidated in vitro or in vivo . To examine individual functions, strains of Salmonella enterica serovar Typhimurium, the murine model of S . Typhi, in which various ECM genes were deleted or added, were created to examine biofilm formation, colonization, and persistence in the gallbladder. Studies show that curli contributes most significantly to biofilm formation. Expression of Vi antigen decreased biofilm formation in vitro and virulence and bacterial survival in vivo without altering the examined gallbladder pro- or anti-inflammatory cytokines. Oppositely, loss of all ECM components (Δ wcaM Δ csgA Δ yihO Δ bcsE ) increased virulence and bacterial survival in vivo and reduced gallbladder interleukin-10 (IL-10) levels. Colanic acid and curli mutants had the largest defects in biofilm-forming ability and contributed most significantly to the virulence increase of the Δ wcaM Δ csgA Δ yihO Δ bcsE mutant strain. While the Δ wcaM Δ csgA Δ yihO Δ bcsE mutant was not altered in resistance to complement or growth in macrophages, it attached and invaded macrophages better than the wild-type (WT) strain. These data suggest that ECM components have various levels of importance in biofilm formation and gallbladder colonization and that the ECM diminishes disseminated disease in our model, perhaps by reducing cell attachment/invasion and dampening inflammation by maintaining/inducing IL-10 production. Understanding how ECM components aid acute disease and persistence could lead to improvements in therapeutic treatment of typhoid fever patients.

scholarly journals Regulation of Tissue Fibrosis by the Biomechanical Environment

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Wayne Carver ◽  
Edie C. Goldsmith
Keyword(s):  
Extracellular Matrix ◽  
Intracellular Signaling ◽  
Mechanical Load ◽  
Mechanical Force ◽  
Mechanical Signals ◽  
Organ Systems ◽  
Extracellular Matrix Components ◽  
Matrix Components

The biomechanical environment plays a fundamental role in embryonic development, tissue maintenance, and pathogenesis. Mechanical forces play particularly important roles in the regulation of connective tissues including not only bone and cartilage but also the interstitial tissues of most organs.In vivostudies have correlated changes in mechanical load to modulation of the extracellular matrix and have indicated that increased mechanical force contributes to the enhanced expression and deposition of extracellular matrix components or fibrosis. Pathological fibrosis contributes to dysfunction of many organ systems. A variety ofin vitromodels have been utilized to evaluate the effects of mechanical force on extracellular matrix-producing cells. In general, application of mechanical stretch, fluid flow, and compression results in increased expression of extracellular matrix components. More recent studies have indicated that tissue rigidity also provides profibrotic signals to cells. The mechanisms whereby cells detect mechanical signals and transduce them into biochemical responses have received considerable attention. Cell surface receptors for extracellular matrix components and intracellular signaling pathways are instrumental in the mechanotransduction process. Understanding how mechanical signals are transmitted from the microenvironment will identify novel therapeutic targets for fibrosis and other pathological conditions.

Effects of soluble factors and extracellular matrix components on vascular cell behavior in vitro and in vivo: Models of de-endothelialization and repair

1991 ◽  
Vol 45 (2) ◽  
pp. 123-130 ◽  
Author(s):  
Joseph A. Madri ◽  
Martin Marx ◽  
June R. Merwin ◽  
Craig Basson ◽  
Christian Prinz ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Behavior ◽  
Soluble Factors ◽  
Vascular Cell ◽  
In Vivo Models ◽  
Extracellular Matrix Components ◽  
Matrix Components

scholarly journals Pathoadaptive Alteration of Salmonella Biofilm Formation in Response to the Gallbladder Environment

2019 ◽  
Vol 201 (14) ◽  
Author(s):  
Michael R. Neiger ◽  
Juan F. González ◽  
Geoffrey Gonzalez-Escobedo ◽  
Harkness Kuck ◽  
Peter White ◽  
...  
Keyword(s):  
Mouse Model ◽  
Typhoid Fever ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Fold Increase ◽  
Nucleotide Polymorphisms ◽  
Wild Type ◽  
Content Type ◽  
Chronic Carriage

ABSTRACT Typhoid fever, a human-specific disease, is primarily caused by the pathogen Salmonella enterica serovar Typhi. It is estimated that 3 to 5% of people infected with typhoid fever become chronic carriers. Studies have demonstrated that a mechanism of chronic carriage involves biofilm formation on gallstone surfaces. In the course of a previous study using a chronic carriage mouse model, a Salmonella enterica serovar Typhimurium isolate was recovered from a mouse gallstone that exhibited a 2-fold increase in biofilm formation over the wild type. In order to identify the gene(s) responsible for the phenotype, the genomic sequences of this isolate and others were determined and compared. These sequences identified single nucleotide polymorphisms (SNPs) in 14 genes. Mutations in the most promising candidates, envZ and rcsB, were created, but neither showed increased biofilm-forming ability separately or in combination. The hyperbiofilm isolate did, however, present variations in cellular appendages observable using different techniques and a preferential binding to cholesterol. The isolate was also examined for systemic virulence and the ability to colonize the gallbladder/gallstones in a mouse model of chronic infection, demonstrating a systemic virulence defect and decreased gallbladder/gallstone colonization. Finally, to determine if the appearance of hyperbiofilm isolates could be replicated in vitro and if this was a common event, wild-type Salmonella spp. were grown long term in vitro under gallbladder-mimicking conditions, resulting in a high proportion of isolates that replicated the hyperbiofilm phenotype of the original isolate. Thus, Salmonella spp. acquire random mutations under the gallbladder/gallbladder-simulating conditions that may aid persistence but negatively affect systemic virulence. IMPORTANCE Chronic carriers are the main reservoirs for the spread of typhoid fever in regions of endemicity. Salmonella Typhi forms biofilms on gallstones in order to persist. A strain with enhanced biofilm-forming ability was recovered after a nine-month chronic-carriage mouse study. After sequencing this strain and recreating some of the mutations, we could not duplicate the phenotype. The isolate did show a difference in flagella, a preference to bind to cholesterol, and a systemic virulence defect. Finally, gallbladder conditions were simulated in vitro. After 60 days, there was a 4.5-fold increase in hyperbiofilm isolates when a gallstone was present. These results indicate that Salmonella spp. can undergo genetic changes that improve persistence in gallbladder albeit at the cost of decreased virulence.

scholarly journals Host factors abolish the need for polysaccharides and extracellular matrix-binding protein in Staphylococcus epidermidis biofilm formation

2021 ◽  
Author(s):  
Sandra M. Skovdal ◽  
Liva Kjær Hansen ◽  
Diana Malskær Ivarsen ◽  
Guanghong Zeng ◽  
Henning Büttner ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Human Plasma ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Type Species ◽  
Host Factors ◽  
Content Type ◽  
Link Type ◽  
Matrix Components

Introduction. Staphylococcus epidermidis is predominant in implant-associated infections due to its capability to form biofilms. It can deploy several strategies for biofilm development using either polysaccharide intercellular adhesin (PIA), extracellular DNA (eDNA) and/or proteins, such as the extracellular matrix-binding protein (Embp). Hypothesis/Gap Statement. We hypothesize that the dichotomic regulation of S. epidermidis adhesins is linked to whether it is inside a host or not, and that in vitro biofilm investigations in laboratory media may not reflect actual biofilms in vivo. Aim. We address the importance of PIA and Embp in biofilm grown in ‘humanized’ media to understand if these components play different roles in biofilm formation under conditions where bacteria can incorporate host proteins in the biofilm matrix. Methodology. S. epidermidis 1585 WT (deficient in icaADBC), and derivative strains that either lack embp, express embp from an inducible promotor, or express icaADBC from a plasmid, were cultivated in standard laboratory media, or in media with human plasma or serum. The amount, structure, elasticity and antimicrobial penetration of biofilms was quantified to describe structural differences caused by the different matrix components and growth conditions. Finally, we quantified the initiation of biofilms as suspended aggregates in response to host factors to determine how quickly the cells aggregate in response to the host environment and reach a size that protects them from phagocytosis. Results. S. epidermidis 1585 required polysaccharides to form biofilm in laboratory media. However, these observations were not representative of the biofilm phenotype in the presence of human plasma. If human plasma were present, polysaccharides and Embp were redundant for biofilm formation. Biofilms formed in human plasma were loosely attached and existed mostly as suspended aggregates. Aggregation occurred after 2 h of exposing cells to plasma or serum. Despite stark differences in the amount and composition of biofilms formed by polysaccharide-producing and Embp-producing strains in different media, there were no differences in vancomycin penetration or susceptibility. Conclusion. We suggest that the assumed importance of polysaccharides for biofilm formation is an artefact from studying biofilms in laboratory media void of human matrix components. The cell–cell aggregation of S. epidermidis can be activated by host factors without relying on either of the major adhesins, PIA and Embp, indicating a need to revisit the basic question of how S. epidermidis deploys self-produced and host-derived matrix components to form antibiotic-tolerant biofilms in vivo.

Megakaryocytes Contribute To The Establishment Of The Bone Marrow Environment By Expressing Extracellular Matrix proteins

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3695-3695
Author(s):  
Alessandro Malara ◽  
Cristian Gruppi ◽  
Manuela Currao ◽  
Alessandra Balduini
Keyword(s):  
Bone Marrow ◽  
Extracellular Matrix ◽  
Type Iv Collagen ◽  
Extracellular Matrix Component ◽  
Matrix Component ◽  
Type Iv ◽  
Extracellular Matrix Components ◽  
Matrix Components

Abstract Introduction the bone marrow microenvironment consists of various types of cells and their secreted extracellular matrix components that surround capillary-venous sinusoids, and plays a key role in the regulation of hematopoiesis. In general, extracellular matrix components interact with each other to form a structural framework that supports tissue organization and positional cues that regulate cellular processes. Megakaryocytes are rare cells in the bone marrow and, besides platelet release, growing evidences attribute new functions to these cells in the generation and maintenance of the bone marrow cell niche. Recent evidences, by our group, demonstrated that megakaryocytes are involved in matrix deposition and remodeling, as demonstrated by their role in fibronectin fibrillogenesis and the expression of matrix cross-linking enzymes, such as factor XIIIa, essential in the dynamic of megakaryocyte-matrix component interactions. Interestingly, individual extracellular matrix components were demonstrated to play a role in the regulation of megakaryocytes development in vitro. Fibronectin was shown to regulate megakaryocyte maturation and proplatelet extension, while type III and type IV collagens were demonstrated to support proplatelet formation in vitro. In contrast, type I collagen is an important physiological inhibitor of platelet release in vitro. However, little is known about the exact localization as well as function of these matrix components in vivo. Results in this work we have analyzed the spatial distribution of megakaryocytes and extracellular matrix components by immunofluorescence in murine femur sections. We found that megakaryocytes were predominantly located in the femur diaphysis with only 20% of megakaryocytes within 50μm from the endosteal surface and more than 80% of megakaryocytes located less than 50 μm from a sinusoid. Correlation between megakaryocyte distance from sinusoids and dimension suggested a gradient of maturing megakaryocytes towards the vascular niche. Next, we deciphered bone marrow extracellular matrix component composition by western blotting and mapped the location in situ of different collagens (I, III, IV, VI) and glycoproteins (fibronectin, laminin). We found that all these proteins were differently located in the endosteal and sinusoidal districts supporting the concept that regulation of hemopoiesis, in the bone marrow, may also depend from matrix distribution. Further, we showed, for the first time, that megakaryocytes were surrounded by a pericellular matrix mainly composed of fibronectin, laminin and type IV collagen. Interestingly, these three proteins were also demonstrated to promote thrombopoietin-dependent megakaryocyte differentiation in in vitro cultures of bone marrow hemopoietic progenitor cells. Finally, fibronectin, laminin and type IV collagen were also demonstrated to be expressed and synthesized by differentiated megakaryocytes in vitro as demonstrated by PCR and western blotting analysis. Most importantly, megakaryocyte expression of these extracellular matrix components was up-regulated in vivo during bone marrow reconstitution upon drug induced myelosuppression and, at a lesser extent, thrombocytopenia. Conclusions all together these results suggested that megakaryocytes are important extracellular matrix component-producing bone marrow cells and that released extracellular matrix components support megakaryopoiesis and concur to the generation of bone marrow niches. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Human Bile-Mediated Regulation of Salmonella Curli Fimbriae

2019 ◽  
Vol 201 (18) ◽  
Author(s):  
Juan F. González ◽  
Lauren Tucker ◽  
James Fitch ◽  
Amy Wetzel ◽  
Peter White ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Typhoid Fever ◽  
Salmonella Enterica ◽  
Human Bile ◽  
Content Type ◽  
Qrt Pcr ◽  
Major Structural Component ◽  
Chronic Carriage ◽  
Coated Surfaces

ABSTRACT Typhoid fever is caused primarily by Salmonella enterica serovar Typhi. Approximately 3% to 5% of individuals infected with S. Typhi become chronic carriers with the gallbladder (GB) as the site of persistence, as gallstones within the GB are a platform on which the bacteria form a biofilm. S. Typhi is a human-restricted pathogen; therefore, asymptomatic carriers represent a critical reservoir for further spread of disease. To examine the dynamics of the Salmonella biofilm during chronic carriage, the human gallstone (GS) environment was simulated by growing biofilms on cholesterol-coated surfaces in the presence of bile, and the transcriptional profile was determined. Some of the most highly activated genes corresponded to the curli fimbria operon, with the major structural component csgA upregulated >80-fold. The curli protein polymer is a major component of the extracellular matrix (ECM) in Salmonella biofilms. The upregulation of curli fimbriae by human bile was validated through reverse transcription-quantitative PCR (qRT-PCR), microscopy, and Western blotting. Interestingly, this activation appears human specific, as qRT-PCR showed repression of csgA in biofilms grown in mouse or ox bile. Comparative transcriptional studies of the two divergent csg operons suggest an early activation of both operons in minimal medium complemented with glucose that quickly diminishes as the biofilm matures. However, in the presence of human bile, there is a modest activation of both operons that steadily increases as the biofilm matures. Understanding the effect of the GB environment on key biofilm-associated factors can help target antibiofilm therapeutics or other preventative strategies to eradicate chronic carriage. IMPORTANCE Typhoid fever is caused by Salmonella enterica serovar Typhi, and 3% to 5% of patients become chronic gallbladder (GB) carriers (also known as “Typhoid Marys”). We have previously demonstrated a role for Salmonella biofilm formation on gallstones as a primary mechanism of carriage. In this study, we found that the important biofilm extracellular matrix component curli fimbria is induced in an in vitro human GB model system. This induction is specific to human bile and increases as the biofilm matures. We also found that the biofilm and curli regulator CsgD play a key role in this observed induction. This work further enhances our understanding biofilm-mediated chronic carriage and provides a potential target for eliminating persistent GB infection by S. Typhi.

scholarly journals SadA, a Trimeric Autotransporter from Salmonella enterica Serovar Typhimurium, Can Promote Biofilm Formation and Provides Limited Protection against Infection

2011 ◽  
Vol 79 (11) ◽  
pp. 4342-4352 ◽  
Author(s):  
Dhaarini Raghunathan ◽  
Timothy J. Wells ◽  
Faye C. Morris ◽  
Robert K. Shaw ◽  
Saeeda Bobat ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Protective Antigen ◽  
Outer Membrane Proteins ◽  
Cell Aggregation ◽  
Sub Saharan Africa ◽  
Content Type ◽  
Serovar Typhimurium

ABSTRACTSalmonella entericais a major cause of morbidity worldwide and mortality in children and immunocompromised individuals in sub-Saharan Africa. Outer membrane proteins ofSalmonellaare of significance because they are at the interface between the pathogen and the host, they can contribute to adherence, colonization, and virulence, and they are frequently targets of antibody-mediated immunity. In this study, the properties of SadA, a purported trimeric autotransporter adhesin ofSalmonella entericaserovar Typhimurium, were examined. We demonstrated that SadA is exposed on theSalmonellacell surfacein vitroandin vivoduring infection of mice. Expression of SadA resulted in cell aggregation, biofilm formation, and increased adhesion to human intestinal Caco-2 epithelial cells. Immunization of mice with folded, full-length, purified SadA elicited an IgG response which provided limited protection against bacterial challenge. When anti-SadA IgG titers were enhanced by administering alum-precipitated protein, a modest additional protection was afforded. Therefore, despite SadA having pleiotropic functions, it is not a dominant, protective antigen for antibody-mediated protection againstSalmonella.

scholarly journals Pulmonary Surfactant Promotes Virulence Gene Expression and Biofilm Formation inKlebsiella pneumoniae

2018 ◽  
Vol 86 (7) ◽  
Author(s):  
Graham G. Willsey ◽  
Sebastian Ventrone ◽  
Kristin C. Schutz ◽  
Aaron M. Wallace ◽  
John W. Ribis ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Pulmonary Surfactant ◽  
De Novo ◽  
Efflux Pump ◽  
Initial Point ◽  
Bacterial Survival ◽  
Content Type ◽  
Insight Into

ABSTRACTThe interactions betweenKlebsiella pneumoniaeand the host environment at the site of infection are largely unknown. Pulmonary surfactant serves as an initial point of contact for inhaled bacteria entering the lung and is thought to contain molecular cues that aid colonization and pathogenesis. To gain insight into this ecological transition, we characterized the transcriptional response ofK. pneumoniaeMGH 78578 to purified pulmonary surfactant. This work revealed changes within theK. pneumoniaetranscriptome that likely contribute to host colonization, adaptation, and virulencein vivo. Notable transcripts expressed under these conditions include genes involved in capsule synthesis, lipopolysaccharide modification, antibiotic resistance, biofilm formation, and metabolism. In addition, we tested the contributions of other surfactant-induced transcripts toK. pneumoniaesurvival using engineered isogenic KPPR1 deletion strains in a murine model of acute pneumonia. In these infection studies, we identified the MdtJI polyamine efflux pump and the ProU glycine betaine ABC transporter to be significant mediators ofK. pneumoniaesurvival within the lung and confirmed previous evidence for the importance ofde novoleucine synthesis to bacterial survival during infection. Finally, we determined that pulmonary surfactant promoted type 3 fimbria-mediated biofilm formation inK. pneumoniaeand identified two surfactant constituents, phosphatidylcholine and cholesterol, that drive this response. This study provides novel insight into the interactions occurring betweenK. pneumoniaeand the host at an important infection site and demonstrates the utility of purified lung surfactant preparations for dissecting host-lung pathogen interactionsin vitro.

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