Author Correction: Modulating bacterial and gut mucosal interactions with engineered biofilm matrix proteins

ABSTRACTPseudomonas aeruginosaproduces an extracellular biofilm matrix that consists of nucleic acids, exopolysaccharides, lipid vesicles, and proteins. In general, the protein component of the biofilm matrix is poorly defined and understudied relative to the other major matrix constituents. While matrix proteins have been suggested to provide many functions to the biofilm, only proteins that play a structural role have been characterized thus far. Here we identify proteins enriched in the matrix ofP. aeruginosabiofilms. We then focused on a candidate matrix protein, the serine protease inhibitor ecotin (PA2755). This protein is able to inhibit neutrophil elastase, a bactericidal enzyme produced by the host immune system duringP. aeruginosabiofilm infections. We show that ecotin binds to the key biofilm matrix exopolysaccharide Psl and that it can inhibit neutrophil elastase when associated with Psl. Finally, we show that ecotin protects both planktonic and biofilmP. aeruginosacells from neutrophil elastase-mediated killing. This may represent a novel mechanism of protection for biofilms to increase their tolerance against the innate immune response.IMPORTANCEProteins associated with the extracellular matrix of bacterial aggregates called biofilms have long been suggested to provide many important functions to the community. To date, however, only proteins that provide structural roles have been described, and few matrix-associated proteins have been identified. We developed a method to identify matrix proteins and characterized one. We show that this protein, when associated with the biofilm matrix, can inhibit a bactericidal enzyme produced by the immune system during infection and protect biofilm cells from death induced by the enzyme. This may represent a novel mechanism of protection for biofilms, further increasing their tolerance against the immune response. Together, our results are the first to show a nonstructural function for a confirmed matrix-interacting protein.

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Biofilm Matrix Proteins

Microbiology Spectrum ◽

10.1128/microbiolspec.mb-0004-2014 ◽

2015 ◽

Vol 3 (2) ◽

Cited By ~ 86

Author(s):

Jiunn N. C. Fong ◽

Fitnat H. Yildiz

Keyword(s):

Matrix Proteins ◽

Biofilm Matrix

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Interplay between Cyclic AMP-Cyclic AMP Receptor Protein and Cyclic di-GMP Signaling in Vibrio cholerae Biofilm Formation

Journal of Bacteriology ◽

10.1128/jb.00466-08 ◽

2008 ◽

Vol 190 (20) ◽

pp. 6646-6659 ◽

Cited By ~ 102

Author(s):

Jiunn C. N. Fong ◽

Fitnat H. Yildiz

Keyword(s):

Cyclic Amp ◽

Vibrio Cholerae ◽

Transcriptome Analysis ◽

Biofilm Formation ◽

Matrix Proteins ◽

Receptor Protein ◽

Camp Receptor Protein ◽

Genes Encoding ◽

Camp Receptor ◽

Biofilm Matrix

ABSTRACT Vibrio cholerae is a facultative human pathogen. The ability of V. cholerae to form biofilms is crucial for its survival in aquatic habitats between epidemics and is advantageous for host-to-host transmission during epidemics. Formation of mature biofilms requires the production of extracellular matrix components, including Vibrio polysaccharide (VPS) and matrix proteins. Biofilm formation is positively controlled by the transcriptional regulators VpsR and VpsT and is negatively regulated by the quorum-sensing transcriptional regulator HapR, as well as the cyclic AMP (cAMP)-cAMP receptor protein (CRP) regulatory complex. Transcriptome analysis of cyaA (encoding adenylate cyclase) and crp (encoding cAMP receptor protein) deletion mutants revealed that cAMP-CRP negatively regulates transcription of both VPS biosynthesis genes and genes encoding biofilm matrix proteins. Further mutational and expression analysis revealed that cAMP-CRP negatively regulates transcription of vps genes indirectly through its action on vpsR transcription. However, negative regulation of the genes encoding biofilm matrix proteins by cAMP-CRP can also occur independent of VpsR. Transcriptome analysis also revealed that cAMP-CRP regulates the expression of a set of genes encoding diguanylate cyclases (DGCs) and phosphodiesterases. Mutational and phenotypic analysis of the differentially regulated DGCs revealed that a DGC, CdgA, is responsible for the increase in biofilm formation in the Δcrp mutant, showing the connection between of cyclic di-GMP and cAMP signaling in V. cholerae.

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An Electrostatic Net Model for the Role of Extracellular DNA in Biofilm Formation by Staphylococcus aureus

Journal of Bacteriology ◽

10.1128/jb.00726-15 ◽

2015 ◽

Vol 197 (24) ◽

pp. 3779-3787 ◽

Cited By ~ 48

Author(s):

Vanina Dengler ◽

Lucy Foulston ◽

Alicia S. DeFrancesco ◽

Richard Losick

Keyword(s):

Staphylococcus Aureus ◽

Biofilm Formation ◽

Extracellular Dna ◽

Matrix Proteins ◽

Exogenous Dna ◽

Content Type ◽

Cytoplasmic Proteins ◽

The Matrix ◽

Biofilm Matrix

ABSTRACTStaphylococcus aureusis an important human pathogen that can form biofilms on various surfaces. These cell communities are protected from the environment by a self-produced extracellular matrix composed of proteins, DNA, and polysaccharide. The exact compositions and roles of the different components are not fully understood. In this study, we investigated the role of extracellular DNA (eDNA) and its interaction with the recently identified cytoplasmic proteins that have a moonlighting role in the biofilm matrix. These matrix proteins associate with the cell surface upon the drop in pH that naturally occurs during biofilm formation, and we found here that this association is independent of eDNA. Conversely, the association of eDNA with the matrix was dependent on matrix proteins. Both proteinase and DNase treatments severely reduced clumping of resuspended biofilms; highlighting the importance of both proteins and eDNA in connecting cells together. By adding an excess of exogenous DNA to DNase-treated biofilm, clumping was partially restored, confirming the crucial role of eDNA in the interconnection of cells. On the basis of our results, we propose that eDNA acts as an electrostatic net, interconnecting cells surrounded by positively charged matrix proteins at a low pH.IMPORTANCEExtracellular DNA (eDNA) is an important component of the biofilm matrix of diverse bacteria, but its role in biofilm formation is not well understood. Here we report that inStaphylococcus aureus, eDNA associates with cells in a manner that depends on matrix proteins and that eDNA is required to link cells together in the biofilm. These results confirm previous studies that showed that eDNA is an important component of theS. aureusbiofilm matrix and also suggest that eDNA acts as an electrostatic net that tethers cells together via the proteinaceous layer of the biofilm matrix.

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Role of Vibrio polysaccharide (vps) genes in VPS production, biofilm formation and Vibrio cholerae pathogenesis

Microbiology ◽

10.1099/mic.0.040196-0 ◽

2010 ◽

Vol 156 (9) ◽

pp. 2757-2769 ◽

Cited By ~ 135

Author(s):

Jiunn C. N. Fong ◽

Khalid A. Syed ◽

Karl E. Klose ◽

Fitnat H. Yildiz

Keyword(s):

Vibrio Cholerae ◽

Biofilm Formation ◽

Matrix Protein ◽

Biochemical Characterization ◽

Gene Clusters ◽

Matrix Proteins ◽

Gene Products ◽

Natural Ecosystems ◽

Infant Mouse ◽

Biofilm Matrix

Biofilm formation enhances the survival and persistence of the facultative human pathogen Vibrio cholerae in natural ecosystems and its transmission during seasonal cholera outbreaks. A major component of the V. cholerae biofilm matrix is the Vibrio polysaccharide (VPS), which is essential for development of three-dimensional biofilm structures. The vps genes are clustered in two regions, the vps-I cluster (vpsU, vpsA–K, VC0916–27) and the vps-II cluster (vpsL–Q, VC0934–39), separated by an intergenic region containing the rbm gene cluster that encodes biofilm matrix proteins. In-frame deletions of the vps clusters and genes encoding matrix proteins drastically altered biofilm formation phenotypes. To determine which genes within the vps gene clusters are required for biofilm formation and VPS synthesis, we generated in-frame deletion mutants for all the vps genes. Many of these mutants exhibited reduced capacity to produce VPS and biofilms. Infant mouse colonization assays revealed that mutants lacking either vps clusters or rbmA (encoding secreted matrix protein RbmA) exhibited a defect in intestinal colonization compared to the wild-type. Understanding the roles of the various vps gene products will aid in the biochemical characterization of the VPS biosynthetic pathway and elucidate how vps gene products contribute to VPS biosynthesis, biofilm formation and virulence in V. cholerae.

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Best served small: nano battles in the war against wound biofilm infections

Emerging Topics in Life Sciences ◽

10.1042/etls20200155 ◽

2020 ◽

Vol 4 (6) ◽

pp. 567-580

Author(s):

Joanna Shepherd

Keyword(s):

Extracellular Matrix ◽

Antimicrobial Resistance ◽

Biomedical Applications ◽

Matrix Proteins ◽

Current Role ◽

Global Challenge ◽

Microbial Biofilms ◽

Wound Biofilms ◽

Biofilm Matrix

The global challenge of antimicrobial resistance is of increasing concern, and alternatives to currently used antibiotics or methods to improve their stewardship are sought worldwide. Microbial biofilms, complex 3D communities of bacteria and/or fungi, are difficult to treat with antibiotics for several reasons. These include their protective coats of extracellular matrix proteins which are difficult for antibiotics to penetrate. Nanoparticles (NP) are one way to rise to this challenge; whilst they exist in many forms naturally there has been a profusion in synthesis of these small (<100 nm) particles for biomedical applications. Their small size allows them to penetrate the biofilm matrix, and as well as some NP being inherently antimicrobial, they also can be modified by doping with antimicrobial payloads or coated to increase their effectiveness. This mini-review examines the current role of NP in treating wound biofilms and the rise in multifunctionality of NP.

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Modulating bacterial and gut mucosal interactions with engineered biofilm matrix proteins

Scientific Reports ◽

10.1038/s41598-018-21834-8 ◽

2018 ◽

Vol 8 (1) ◽

Cited By ~ 15

Author(s):

Anna M. Duraj-Thatte ◽

Pichet Praveschotinunt ◽

Trevor R. Nash ◽

Frederick R. Ward ◽

Neel S. Joshi

Keyword(s):

Matrix Proteins ◽

Biofilm Matrix

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Distribution of VLA-5 and VLA-4 fibronectin receptors in human monocytes demonstrated by immunofluorescence, immunocytochemistry, and autoradiography

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100147375 ◽

1993 ◽

Vol 51 ◽

pp. 306-307

Author(s):

Robert Williams ◽

Che-Hung Lee ◽

Sara E. Quella ◽

David M. Harlan ◽

Yuan-Hsu Kang

Keyword(s):

Present Report ◽

Matrix Proteins ◽

Extracellular Matrices ◽

Human Monocytes ◽

Integrin Receptors ◽

Morphological Evaluation ◽

The Matrix ◽

Specific Receptors ◽

Cytokine Stimulation ◽

Monocyte Adherence

Monocyte adherence to endothelial or extracellular matrices plays an important role in triggering monocyte activation in extravascular sites of infection, chronic inflammatory disorders, and tissue damage. Migration of monocytes in the tissues involves the response to a chemoattractant and movement by a series of attachments and detachments to the extracellular matrices which are regulated by expression and distribution of specific receptors for the matrix proteins such as fibronectin (FN). The VSAs (very late antigens or beta integrins), a subfamily of the transmembrane heterodimeric integrin receptors, have been thought to play a major role in monocyte adherence to the extracellular matrices and cells. In this subfamily, VLA-5 and VLA-4 are believed to be the most essential integrins mediating monocyte adherence to FN. In the present report, we have established and compared different procedures for morphological evaluation of the expression and distribution of the FN receptors on human monocytes in order to investigate their response to endotoxin or cytokine stimulation.

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Development of an in vitro Model for the Study of the Response of Equine Tendon Fibroblasts to Injury and Medication

Veterinary and Comparative Orthopaedics and Traumatology ◽

10.1055/s-0038-1632561 ◽

1997 ◽

Vol 10 (01) ◽

pp. 6-11 ◽

Cited By ~ 3

Author(s):

R. F. Rosenbusch ◽

L. C. Booth ◽

L. A. Dahlgren

Keyword(s):

Electron Microscopy ◽

Extracellular Matrix ◽

Light Microscopy ◽

Light And Electron Microscopy ◽

Tendon Healing ◽

Matrix Proteins ◽

Isolated Cells ◽

Superficial Digital Flexor Tendon ◽

Vitro Model

SummaryEquine tendon fibroblasts were isolated from explants of superficial digital flexor tendon, subcultured and maintained in monolayers. The cells were characterized by light microscopy, electron microscopy and radiolabel studies for proteoglycan production. Two predominant cell morphologies were identified. The cells dedifferentiated toward a more spindle shape with repeated subcultures. Equine tendon fibroblasts were successfully cryopreserved and subsequently subcultured. The ability to produce proteoglycan was preserved.The isolated cells were identified as fibroblasts, based on their characteristic shape by light microscopy and ultrastructure and the active production of extracellular matrix proteins. Abundant rough endoplasmic reticulum and the production of extracellular matrix products demonstrated active protein production and export. Proteoglycans were measurable via liquid scintillation counting in both the cell-associated fraction and free in the supernatant. This model is currently being utilized to study the effects of polysulfated glycosaminoglycan on tendon healing. Future uses include studying the effects of other pharmaceuticals, such as hyaluronic acid, on tendon healing.A model was developed for in vitro investigations into tendon healing. Fibroblasts were isolated from equine superficial digital flexor tendons and maintained in monolayer culture. The tenocytes were characterized via light and electron microscopy. Proteoglycan production was measured, using radio-label techniques. The fibroblasts were cryopreserved and subsequently subcultured. The cells maintained their capacity for proteoglycan production, following repeated subculturing and cryopreservation.

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