Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Identifying host pathogenic pathways in bovine digital dermatitis by RNA-Seq analysis of lesions

ABSTRACT: Digital dermatitis is a painful foot disease compromising welfare in dairy cattle. The disease has a complex multibacterial aetiology, but little is known about its pathogenesis. In this study, gene expression in skin biopsies from five bovine digital dermatitis lesions and five healthy bovine feet was compared using RNA-Seq technology. Differential gene expression was determined after mapping transcripts to the Btau 4.0 genome. Pathway analysis identified gene networks involving differentially expressed transcripts. Bovine digital dermatitis lesions had increased expression of mRNA for a2-macroglobulin-like 1, a protein potentially involved in bacterial immune evasion and bacterial survival. There was increased expression of keratin 6A and interleukin 1b mRNA in bovine digital dermatitis lesions, but reduced expression of most other keratin and keratin-associated genes. There was little evidence of local immune reactions to the bacterial infection present in lesions. Ten samples were processed; five normal skin biopsies from the hind foot skin and five digital dermatitis lesions (large (>2cm) red raw in appearance).

ORGANISM(S): Bos taurus

SUBMITTER: rachel scholey

PROVIDER: E-GEOD-41732 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Similar Datasets

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.

Project description:Here, we report the first complete genomes of three cultivable treponeme species from bovine digital dermatitis (DD) skin lesions, two comparative human treponemes and a bovine gastrointestinal (GI) isolate. Key genomic differences between bovine and human treponemes implicate microbial mechanisms that enhance knowledge of how DD, a severe disease of ruminants, has emerged into a prolific and endemic disease in countries worldwide. Bovine DD treponemes have additional oxidative stress genes compared to nearest human-isolated relatives, suggesting better toleration of oxidative stress, and thus potentially explaining the ability of bovine strains to colonize skin surfaces. Comparison of bovine DD and GI treponemes as well as bovine pathogenic and human non-pathogenic saprophyte Treponema phagedenis strains indicates genes encoding a five-enzyme biosynthetic pathway for the production of 2,3-diacetamido-2,3-dideoxy-d-mannuronic acid, a rare di-N-acetylated mannuronic acid sugar with potential immunomodulatory activity, as important for pathogenesis. The bovine T. phagedenis strains further differed from human strains by having a larger number of unique genetic features including components of a type IV secretion system and a phosphate utilisation system including phoU, a gene associated with enhanced osmotic stress survival. Proteomic analyses confirmed bovine derived T. phagedenis exhibits expression of PhoU but not the putative secretion system whilst the novel mannuronic acid pathway was expressed in near entirety across the DD treponemes. Analysis of osmotic stress response in water identified a difference between bovine and human T. phagedenis with bovine strains surviving better. This novel mechanism could enable a selective advantage, allowing environmental persistence and transmission of bovine T. phagedenis. Finally, we investigated a range of treponeme genes encoding ortholog families across the DD treponemes representing putative outer membrane proteins (OMPs) and identified several families as multi-specific adhesins capable of binding extra cellular matrix (ECM) components. Human saprophytic T. phagedenis could not be differentiated from bovine pathogenic strains by these adhesins and only two of ten characterised ortholog OMP families were absent from commensal bovine treponemes. One of these bovine pathogen specific adhesin ortholog families showed considerable diagnostic potential with the Treponema medium representative demonstrating the greatest disease specificity (91.6%). This work has shed light on treponeme host adaptation and has identified candidate molecules for future diagnostics, vaccination and therapeutic intervention.

Dataset Information

Identifying host pathogenic pathways in bovine digital dermatitis by RNA-Seq analysis of lesions

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets