Dataset Information

Putative β-Barrel Outer Membrane Proteins of the Bovine Digital Dermatitis-Associated Treponemes: Identification, Functional Characterization, and Immunogenicity.

ABSTRACT: Bovine digital dermatitis (BDD), an infectious disease of the bovine foot with a predominant treponemal etiology, is a leading cause of lameness in dairy and beef herds worldwide. BDD is poorly responsive to antimicrobial therapy and exhibits a relapsing clinical course; an effective vaccine is therefore urgently sought. Using a reverse vaccinology approach, the present study surveyed the genomes of the three BDD-associated Treponema phylogroups for putative β-barrel outer membrane proteins and considered their potential as vaccine candidates. Selection criteria included the presence of a signal peptidase I cleavage site, a predicted β-barrel fold, and cross-phylogroup homology. Four candidate genes were overexpressed in Escherichia coli BL21(DE3), refolded, and purified. Consistent with their classification as β-barrel OMPs, circular-dichroism spectroscopy revealed the adoption of a predominantly β-sheet secondary structure. These recombinant proteins, when screened for their ability to adhere to immobilized extracellular matrix (ECM) components, exhibited a diverse range of ligand specificities. All four proteins specifically and dose dependently adhered to bovine fibrinogen. One recombinant protein was identified as a candidate diagnostic antigen (disease specificity, 75%). Finally, when adjuvanted with aluminum hydroxide and administered to BDD-naive calves using a prime-boost vaccination protocol, these proteins were immunogenic, eliciting specific IgG antibodies. In summary, we present the description of four putative treponemal β-barrel OMPs that exhibit the characteristics of multispecific adhesins. The observed interactions with fibrinogen may be critical to host colonization and it is hypothesized that vaccination-induced antibody blockade of these interactions will impede treponemal virulence and thus be of therapeutic value.

SUBMITTER: Staton GJ

PROVIDER: S-EPMC7171239 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Putative β-Barrel Outer Membrane Proteins of the Bovine Digital Dermatitis-Associated Treponemes: Identification, Functional Characterization, and Immunogenicity.

Staton G J GJ Carter S D SD Ainsworth S S Mullin J J Smith R F RF Evans N J NJ

Infection and immunity 20200420 5

Bovine digital dermatitis (BDD), an infectious disease of the bovine foot with a predominant treponemal etiology, is a leading cause of lameness in dairy and beef herds worldwide. BDD is poorly responsive to antimicrobial therapy and exhibits a relapsing clinical course; an effective vaccine is therefore urgently sought. Using a reverse vaccinology approach, the present study surveyed the genomes of the three BDD-associated <i>Treponema</i> phylogroups for putative β-barrel outer membrane protei ...[more]

PMID: 32122940

Similar Datasets

Project description:Bovine digital dermatitis (BDD) is a common infectious disease of digital skin in cattle and an important cause of lameness worldwide, with limited treatment options. It is of increasing global concern for both animal welfare and food security, imposing a large economic burden on cattle farming industries each year. A polytreponemal etiology has been consistently identified, with three key phylogroups implicated globally: Treponema medium, Treponema phagedenis, and Treponema pedis. Pathogenic mechanisms which might enable targeted treatment/therapeutic development are poorly defined. This study used RNA sequencing to determine global differential mRNA expression in primary bovine foot skin fibroblasts following challenge with three representative BDD treponemes and a commensal treponeme, Treponema ruminis. A pro-inflammatory response was elicited by the BDD treponemes, mediated through IL-8/IL-17 signaling. Unexpectedly, the three BDD treponemes elicited distinct mechanisms of pathogenesis. T. phagedenis and T. pedis increased abundance of mRNA transcripts associated with apoptosis, while T. medium and T. pedis increased transcripts involved in actin rearrangement and loss of cell adhesion, likely promoting tissue invasion. The upregulation of antimicrobial peptide precursor, DEFB123, by T. phagedenis spirochaetes may present a microbial ecological advantage to all treponemes within BDD infected tissue, explaining their dominance within lesions. A commensal, T. ruminis, significantly dysregulated over three times the number of host mRNA transcripts compared to BDD treponemes, implying BDD treponemes, akin to the syphilis pathogen (Treponema pallidum), have evolved as "stealth pathogens" which avoid triggering substantial host immune/inflammatory responses to enable persistence and tissue invasion. Immunohistochemistry demonstrated increased IL-6, IL-8, RND1, and CFB protein expression in BDD lesions, confirming in vitro fibroblast observations and highlighting the system's value in modeling BDD pathogenesis. Several unique shared gene targets were identified, particularly RGS16, GRO1, MAFF, and ZC3H12A. The three key BDD Treponema phylogroups elicited both distinct and shared pathogenic mechanisms in bovine foot skin; upregulating inflammation whilst simultaneously suppressing adaptive immunity. The novel gene targets identified here should enable future vaccine/therapeutic approaches.

Project description:Purpose, aims and objectives: Bovine digital dermatitis (BDD) is a painful and ulcerative, inflammatory, infectious disease of digital skin in dairy and beef cattle and is one of the most economically important causes of severe cattle lameness worldwide. A polytreponemal aetiology has been consistently implicated in BDD pathogenesis with three key phylogroups implicated globally: Treponema medium, Treponema phagedenis and Treponema pedis. This study aimed to investigate the hypothesis that the three Treponema phylogroups implement distict mechanisms of pathogenesis within cells of the bovine foot skin tissue during infection. Using a next generation RNA sequencing (RNA-Seq) approach, the dysregulation of global mRNA expression was investigated in primary bovine foot skin fibroblasts following challenge with representative strains of the three predominant BDD Treponema phylogroups (T19, T320A and T3552B respectively). Transcriptome profiles were compared to that of a commensal treponeme, Treponema ruminis strain Ru1, in attempts to identify pathogenic signatures. Results and conclusions: Here, for the first time, we implicate fibroblasts as a likely source of interleukin-8 dysregulation in BDD lesions. Despite treponemes reportedly having atypical LPS, a strong pro-inflammatory response was elicited by the BDD treponemes in a similar manner to the Gram-negative LPS control, which appeared to be mediated through interleukin-17 signalling. Along with interleukin-17, several interesting gene targets were identified which may help to inform and drive future vaccine development and therapeutic approaches; particularly those of RGS16, GRO1, MAFF and ZC3H12A, which were only stimulated by BDD treponemes. Interestingly, the three BDD treponemes were found to elicit very distinct mechanisms of pathogenesis in fibroblasts. T. phagedenis and T. pedis spirochaetes were found to upregulate several genes associated with apoptosis. Both T. medium and T. pedis spirochaetes, but notably not T. phagedenis, stimulated genes associated with actin rearrangement and a loss of cell adhesion, which may promote their persistence and deeper invasion within host tissues. The upregulation of antimicrobial peptide precursor, DEFB123, by T. phagedenis spirochaetes may present a microbial ecological advantage to all treponemes within BDD infected tissue, explaining their dominance within lesions. Interestingly, T. medium phylogroup was the least stimulatory and appeared to induce immunosuppression via the dysregulation of genes such as TSC22D3. Together with findings that the commensal, T. ruminis, significantly dysregulated over three times the number of host genes compared to each BDD treponeme; this suggests that, alike the syphilis pathogen (Treponema pallidum), BDD treponemes have evolved to become “stealth pathogens” and avoid triggering a substantial host immune/inflammatory response to promote persistence and facilitate invasion of host tissues. Overall, this study has highlighted the complexities of BDD pathogenesis; three key Treponema phylogroups appear to elicit very distinct mechanisms of pathogenesis in bovine foot skin cells. Several interesting gene targets have been identified from this study which may help to inform and drive future vaccine development and therapeutic approaches.

Dataset Information

Putative β-Barrel Outer Membrane Proteins of the Bovine Digital Dermatitis-Associated Treponemes: Identification, Functional Characterization, and Immunogenicity.

Publications

Putative β-Barrel Outer Membrane Proteins of the Bovine Digital Dermatitis-Associated Treponemes: Identification, Functional Characterization, and Immunogenicity.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets