Gilad Bachrach - Academia.edu (original) (raw)

Papers by Gilad Bachrach

Fusobacterium nucleatum is an opportunistic bacterial pathogen and oncogenic microbe. Using host ... more Fusobacterium nucleatum is an opportunistic bacterial pathogen and oncogenic microbe. Using host sequencing data to systematically investigate Fusobacterium-host interactions in colorectal cancers (CRCs), we developed and orthogonally validated a multi-omics PAThogen CHaracterisation tool (PATCH) enabling gene-level annotations. In 1,020 CRC transcriptomes and 86 genomes from The Cancer Genome Atlas (TCGA), 9 Fusobacterium species were detected to gene-level resolution identifying carcinogenic virulence factors. PATCH uncovered the integration of Fusobacterium’s DNA into the host genome, specifically in non-coding regions and near Short Interspersed Elements. CRCs with integrated-Fusobacterium DNA revealed perturbations in host DNA damage response mechanisms, including deficiencies in chromosome segregation, increased microsatellite instability, elevated cytosolic DNA/RNA sensing signalling, and mutations in genes involved in oncogenic-related pathways. Fusobacterium-positive CRCs e...

Periodontology 2000, 2022

Accumulating evidence demonstrates that the oral pathobiont Fusobacterium nucleatum is involved i... more Accumulating evidence demonstrates that the oral pathobiont Fusobacterium nucleatum is involved in the progression of an increasing number of tumors types. Thus far, the mechanisms underlying tumor exacerbation by F. nucleatum include the enhancement of proliferation, establishment of a tumor-promoting immune environment, induction of chemoresistance, and the activation of immune checkpoints. This review focuses on the mechanisms that mediate tumor-specific colonization by fusobacteria. Elucidating the mechanisms mediating fusobacterial tumor tropism and promotion might provide new insights for the development of novel approaches for tumor detection and treatment.

Frontiers in Cellular and Infection Microbiology, 2021

Recent studies on the oral, anaerobic, gram-negative bacterium Fusobacterium nucleatum revealed i... more Recent studies on the oral, anaerobic, gram-negative bacterium Fusobacterium nucleatum revealed its presence and involvement in colorectal, esophageal and breast cancer. We previously demonstrated that F. nucleatum binds and activates the human inhibitory receptors TIGIT and CEACAM1 leading to inhibition of T and NK cell anti-tumor immunity. CEACAM1 was found to be bound and activated by the fusobacterial trimeric autotransporter adhesin CbpF. Here we report the generation of a recombinant E. coli expressing full-length CbpF that efficiently binds and activates CEACAM1.

Oral Microbial Communities

Fusobacterium nucleatum is an oral anaerobe and the most common gram-negative isolate from both h... more Fusobacterium nucleatum is an oral anaerobe and the most common gram-negative isolate from both healthy and diseased oral sites. Association of F. nucleatum with gingivitis and with its progression to periodontal disease has been based on the fact that numbers of F. nucleatum organisms greatly increase in samples taken from diseased sites compared to those from healthy ones. The author feels that the sharing of both gram-positive and gram-negative properties might facilitate communication of fusobacteria with both gram-positive early colonizers and gram-negative late colonizers, an essential stage in the development of the periopathogenic dental biofilm. The species complexity of oral biofilms is probably the greatest hurdle in studying the fusobacterial role in oral health and disease. The author proposes that fusobacterial virulence relies on the presence of its adhesins and not on classical toxins and proteases. Microarrays can be designed to interact uniquely with F. nucleatum gene transcripts. These microarrays can be reacted with total RNAs extracted from dental biofilms sampled from healthy and diseased periodontal sites of increasing disease severity. In vitro studies have suggested that fusobacterial bridging coaggregation interactions are important for the shift in the composition of the microbial community associated with transition from health to disease. Ongoing introduction of tools for genetic manipulation of fusobacteria will enable the investigation of fusobacterial virulence-associated molecular elements. Integration species-specific and general molecular tools is expected to enable the study and the understanding of F. nucleatum's role in bridging from oral health to disease.

Effect of pH on bundling. 8 μM F-actin was bundled by 3–12 μM histatin-3 or 3–16 μM histatin-5 at... more Effect of pH on bundling. 8 μM F-actin was bundled by 3–12 μM histatin-3 or 3–16 μM histatin-5 at pH 6.5 and 7.4. Extent of bundling measured by low speed (20,800xg for 8 min) centrifugation and evaluated by densitometry of the SDS-PAGE of supernatants (unbundled actin) as described in Materials and Methods. (TIFF 192 kb)

Infection and Immunity, 1994

A delayed-type hypersensitivity (DTH) reaction in the course of brucellosis in humans and animals... more A delayed-type hypersensitivity (DTH) reaction in the course of brucellosis in humans and animals can be revealed by the brucellin INRA (Brucellergen) skin test. Brucellergen is composed of more than 20 proteins of different molecular weights. A 12-kDa protein eliciting DTH in Brucella melitensis Rev1-sensitized guinea pigs was found to be a significant component for the allergenic properties of Brucellergen. Sequencing of the gene encoding this protein identified it as the L7/L12 ribosomal protein. The L7/L12 gene of B. melitensis was amplified by PCR and subcloned in the Escherichia coli pQE30 plasmid. The resulting recombinant protein did not produce a DTH reaction in sensitized animals. It was used to raise specific antibodies in a rabbit. Affinity chromatography with these antibodies was used to isolate a single protein from Brucellergen and from B. melitensis cytosol preparations which produced a DTH reaction in guinea pigs sensitized with B. melitensis Rev1. N-terminal amino ...

Infection and immunity, 2015

Fusobacterium nucleatum is a common oral anaerobe involved in periodontitis that is known to tran... more Fusobacterium nucleatum is a common oral anaerobe involved in periodontitis that is known to translocate and cause intrauterine infections. In the oral environment, F. nucleatum adheres to a large diversity of species, facilitating their colonization and creating biological bridges that stabilize the multispecies dental biofilm. Many of these interactions (called coadherences or coaggregations) are galactose sensitive. Galactose-sensitive interactions are also involved in the binding of F. nucleatum to host cells. Hemagglutination of some F. nucleatum strains is also galactose sensitive, suggesting that a single galactose-sensitive adhesin might mediate the interaction of fusobacteria with many partners and targets. In order to identify the fusobacterial galactose-sensitive adhesin, a system for transposon mutagenesis in fusobacteria was created. The mutant library was screened for hemagglutination deficiency, and three clones were isolated. All three clones were found to harbor the...

Frontiers in Cellular and Infection Microbiology, 2021

F. nucleatum is an anaerobic bacterium that is associated with several tumor entities and promote... more F. nucleatum is an anaerobic bacterium that is associated with several tumor entities and promotes tumorigenesis. Recent evidence suggests that F. nucleatum binds the inhibitory receptor carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) via the trimeric autotransporter adhesin CbpF. However, whether this binding is functional or whether other fusobacterial trimeric autotransporter adhesins are involved in CEACAM1 activation is unknown. In this study, using F. nucleatum mutants lacking the type 5c trimeric autotransporter adhesins fvcA (CbpF), fvcB, fvcC, and fvcD, we show that F. nucleatum CbpF binds and activates CEACAM1 and also binds carcinoembryonic antigen (CEA), a tumor-associated protein. We further find that CEACAM antibodies directed against the CEACAM N-terminal domain block the CbpF-CEACAM1 interaction. In functional assays, we demonstrate CbpF-dependent inhibition of CD4+ T cell response. Thus, we characterize an immune evasion mechanism in which F. nucleatum u...

Frontiers in Cellular and Infection Microbiology, 2020

The Journal of Immunology, 2006

FEMS Microbiology Letters, 1994

Antimicrobial Agents and Chemotherapy, 2007

Antimicrobial peptides are short, positively charged, amphipathic peptides that possess a wide sp... more Antimicrobial peptides are short, positively charged, amphipathic peptides that possess a wide spectrum of antimicrobial activity and have an important role in the host's innate immunity. Lack of, or dysfunctions in, antimicrobial peptides have been correlated with infectious diseases, including periodontitis. Porphyromonas gingivalis , a gram-negative anaerobe and a major pathogen associated with periodontal diseases, is resistant to antimicrobial peptides of human and nonhuman origin, a feature that likely contributes to its virulence. Expressing a robust proteolytic activity, P. gingivalis hydrolyzes antimicrobial peptides. In this study, P. gingivalis inactivated three antimicrobial peptides, while a d -enantiomer was resistant to degradation. P. gingivalis was resistant to the protease-resistant d -enantiomer peptide, and importantly, a protease-deficient P. gingivalis mutant was also resistant to the antimicrobial peptide. Finally, the binding of a fluorescently labeled an...

Nature Communications

Fusobacterium nucleatum is an oral anaerobe recently found to be prevalent in human colorectal ca... more Fusobacterium nucleatum is an oral anaerobe recently found to be prevalent in human colorectal cancer (CRC) where it is associated with poor treatment outcome. In mice, hematogenous F. nucleatum can colonize CRC tissue using its lectin Fap2, which attaches to tumor-displayed Gal-GalNAc. Here, we show that Gal-GalNAc levels increase as human breast cancer progresses, and that occurrence of F. nucleatum gDNA in breast cancer samples correlates with high Gal-GalNAc levels. We demonstrate Fap2-dependent binding of the bacterium to breast cancer samples, which is inhibited by GalNAc. Intravascularly inoculated Fap2-expressing F. nucleatum ATCC 23726 specifically colonize mice mammary tumors, whereas Fap2-deficient bacteria are impaired in tumor colonization. Inoculation with F. nucleatum suppresses accumulation of tumor infiltrating T cells and promotes tumor growth and metastatic progression, the latter two of which can be counteracted by antibiotic treatment. Thus, targeting F. nucleat...

Fusobacterium nucleatum is an opportunistic bacterial pathogen and oncogenic microbe. Using host ... more Fusobacterium nucleatum is an opportunistic bacterial pathogen and oncogenic microbe. Using host sequencing data to systematically investigate Fusobacterium-host interactions in colorectal cancers (CRCs), we developed and orthogonally validated a multi-omics PAThogen CHaracterisation tool (PATCH) enabling gene-level annotations. In 1,020 CRC transcriptomes and 86 genomes from The Cancer Genome Atlas (TCGA), 9 Fusobacterium species were detected to gene-level resolution identifying carcinogenic virulence factors. PATCH uncovered the integration of Fusobacterium’s DNA into the host genome, specifically in non-coding regions and near Short Interspersed Elements. CRCs with integrated-Fusobacterium DNA revealed perturbations in host DNA damage response mechanisms, including deficiencies in chromosome segregation, increased microsatellite instability, elevated cytosolic DNA/RNA sensing signalling, and mutations in genes involved in oncogenic-related pathways. Fusobacterium-positive CRCs e...

Periodontology 2000, 2022

Accumulating evidence demonstrates that the oral pathobiont Fusobacterium nucleatum is involved i... more Accumulating evidence demonstrates that the oral pathobiont Fusobacterium nucleatum is involved in the progression of an increasing number of tumors types. Thus far, the mechanisms underlying tumor exacerbation by F. nucleatum include the enhancement of proliferation, establishment of a tumor-promoting immune environment, induction of chemoresistance, and the activation of immune checkpoints. This review focuses on the mechanisms that mediate tumor-specific colonization by fusobacteria. Elucidating the mechanisms mediating fusobacterial tumor tropism and promotion might provide new insights for the development of novel approaches for tumor detection and treatment.

Frontiers in Cellular and Infection Microbiology, 2021

Recent studies on the oral, anaerobic, gram-negative bacterium Fusobacterium nucleatum revealed i... more Recent studies on the oral, anaerobic, gram-negative bacterium Fusobacterium nucleatum revealed its presence and involvement in colorectal, esophageal and breast cancer. We previously demonstrated that F. nucleatum binds and activates the human inhibitory receptors TIGIT and CEACAM1 leading to inhibition of T and NK cell anti-tumor immunity. CEACAM1 was found to be bound and activated by the fusobacterial trimeric autotransporter adhesin CbpF. Here we report the generation of a recombinant E. coli expressing full-length CbpF that efficiently binds and activates CEACAM1.

Oral Microbial Communities

Fusobacterium nucleatum is an oral anaerobe and the most common gram-negative isolate from both h... more Fusobacterium nucleatum is an oral anaerobe and the most common gram-negative isolate from both healthy and diseased oral sites. Association of F. nucleatum with gingivitis and with its progression to periodontal disease has been based on the fact that numbers of F. nucleatum organisms greatly increase in samples taken from diseased sites compared to those from healthy ones. The author feels that the sharing of both gram-positive and gram-negative properties might facilitate communication of fusobacteria with both gram-positive early colonizers and gram-negative late colonizers, an essential stage in the development of the periopathogenic dental biofilm. The species complexity of oral biofilms is probably the greatest hurdle in studying the fusobacterial role in oral health and disease. The author proposes that fusobacterial virulence relies on the presence of its adhesins and not on classical toxins and proteases. Microarrays can be designed to interact uniquely with F. nucleatum gene transcripts. These microarrays can be reacted with total RNAs extracted from dental biofilms sampled from healthy and diseased periodontal sites of increasing disease severity. In vitro studies have suggested that fusobacterial bridging coaggregation interactions are important for the shift in the composition of the microbial community associated with transition from health to disease. Ongoing introduction of tools for genetic manipulation of fusobacteria will enable the investigation of fusobacterial virulence-associated molecular elements. Integration species-specific and general molecular tools is expected to enable the study and the understanding of F. nucleatum's role in bridging from oral health to disease.

Effect of pH on bundling. 8 μM F-actin was bundled by 3–12 μM histatin-3 or 3–16 μM histatin-5 at... more Effect of pH on bundling. 8 μM F-actin was bundled by 3–12 μM histatin-3 or 3–16 μM histatin-5 at pH 6.5 and 7.4. Extent of bundling measured by low speed (20,800xg for 8 min) centrifugation and evaluated by densitometry of the SDS-PAGE of supernatants (unbundled actin) as described in Materials and Methods. (TIFF 192 kb)

Infection and Immunity, 1994

A delayed-type hypersensitivity (DTH) reaction in the course of brucellosis in humans and animals... more A delayed-type hypersensitivity (DTH) reaction in the course of brucellosis in humans and animals can be revealed by the brucellin INRA (Brucellergen) skin test. Brucellergen is composed of more than 20 proteins of different molecular weights. A 12-kDa protein eliciting DTH in Brucella melitensis Rev1-sensitized guinea pigs was found to be a significant component for the allergenic properties of Brucellergen. Sequencing of the gene encoding this protein identified it as the L7/L12 ribosomal protein. The L7/L12 gene of B. melitensis was amplified by PCR and subcloned in the Escherichia coli pQE30 plasmid. The resulting recombinant protein did not produce a DTH reaction in sensitized animals. It was used to raise specific antibodies in a rabbit. Affinity chromatography with these antibodies was used to isolate a single protein from Brucellergen and from B. melitensis cytosol preparations which produced a DTH reaction in guinea pigs sensitized with B. melitensis Rev1. N-terminal amino ...

Infection and immunity, 2015

Fusobacterium nucleatum is a common oral anaerobe involved in periodontitis that is known to tran... more Fusobacterium nucleatum is a common oral anaerobe involved in periodontitis that is known to translocate and cause intrauterine infections. In the oral environment, F. nucleatum adheres to a large diversity of species, facilitating their colonization and creating biological bridges that stabilize the multispecies dental biofilm. Many of these interactions (called coadherences or coaggregations) are galactose sensitive. Galactose-sensitive interactions are also involved in the binding of F. nucleatum to host cells. Hemagglutination of some F. nucleatum strains is also galactose sensitive, suggesting that a single galactose-sensitive adhesin might mediate the interaction of fusobacteria with many partners and targets. In order to identify the fusobacterial galactose-sensitive adhesin, a system for transposon mutagenesis in fusobacteria was created. The mutant library was screened for hemagglutination deficiency, and three clones were isolated. All three clones were found to harbor the...

Frontiers in Cellular and Infection Microbiology, 2021

F. nucleatum is an anaerobic bacterium that is associated with several tumor entities and promote... more F. nucleatum is an anaerobic bacterium that is associated with several tumor entities and promotes tumorigenesis. Recent evidence suggests that F. nucleatum binds the inhibitory receptor carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) via the trimeric autotransporter adhesin CbpF. However, whether this binding is functional or whether other fusobacterial trimeric autotransporter adhesins are involved in CEACAM1 activation is unknown. In this study, using F. nucleatum mutants lacking the type 5c trimeric autotransporter adhesins fvcA (CbpF), fvcB, fvcC, and fvcD, we show that F. nucleatum CbpF binds and activates CEACAM1 and also binds carcinoembryonic antigen (CEA), a tumor-associated protein. We further find that CEACAM antibodies directed against the CEACAM N-terminal domain block the CbpF-CEACAM1 interaction. In functional assays, we demonstrate CbpF-dependent inhibition of CD4+ T cell response. Thus, we characterize an immune evasion mechanism in which F. nucleatum u...

Frontiers in Cellular and Infection Microbiology, 2020

The Journal of Immunology, 2006

FEMS Microbiology Letters, 1994

Antimicrobial Agents and Chemotherapy, 2007

Antimicrobial peptides are short, positively charged, amphipathic peptides that possess a wide sp... more Antimicrobial peptides are short, positively charged, amphipathic peptides that possess a wide spectrum of antimicrobial activity and have an important role in the host's innate immunity. Lack of, or dysfunctions in, antimicrobial peptides have been correlated with infectious diseases, including periodontitis. Porphyromonas gingivalis , a gram-negative anaerobe and a major pathogen associated with periodontal diseases, is resistant to antimicrobial peptides of human and nonhuman origin, a feature that likely contributes to its virulence. Expressing a robust proteolytic activity, P. gingivalis hydrolyzes antimicrobial peptides. In this study, P. gingivalis inactivated three antimicrobial peptides, while a d -enantiomer was resistant to degradation. P. gingivalis was resistant to the protease-resistant d -enantiomer peptide, and importantly, a protease-deficient P. gingivalis mutant was also resistant to the antimicrobial peptide. Finally, the binding of a fluorescently labeled an...

Nature Communications

Fusobacterium nucleatum is an oral anaerobe recently found to be prevalent in human colorectal ca... more Fusobacterium nucleatum is an oral anaerobe recently found to be prevalent in human colorectal cancer (CRC) where it is associated with poor treatment outcome. In mice, hematogenous F. nucleatum can colonize CRC tissue using its lectin Fap2, which attaches to tumor-displayed Gal-GalNAc. Here, we show that Gal-GalNAc levels increase as human breast cancer progresses, and that occurrence of F. nucleatum gDNA in breast cancer samples correlates with high Gal-GalNAc levels. We demonstrate Fap2-dependent binding of the bacterium to breast cancer samples, which is inhibited by GalNAc. Intravascularly inoculated Fap2-expressing F. nucleatum ATCC 23726 specifically colonize mice mammary tumors, whereas Fap2-deficient bacteria are impaired in tumor colonization. Inoculation with F. nucleatum suppresses accumulation of tumor infiltrating T cells and promotes tumor growth and metastatic progression, the latter two of which can be counteracted by antibiotic treatment. Thus, targeting F. nucleat...