Gene expression profiles during subclinical Mycobacterium avium subspecies paratuberculosis infection in sheep can...

Area of Science:

• Veterinary immunology
• Ruminant infectious diseases
• Transcriptomics

Background:

• Paratuberculosis in ruminants is caused by Mycobacterium avium subspecies paratuberculosis (MAP).
• Host immune evasion occurs during the subclinical phase of MAP infection.
• Individual responses to MAP exposure vary, with some animals developing clinical disease while others remain resilient.

Purpose of the Study:

• To identify gene expression changes in Merino sheep experimentally exposed to MAP during the subclinical phase.
• To discover potential biomarkers associated with MAP exposure, disease outcome, or resilience.
• To understand the host's cellular adaptations to MAP infection.

Main Methods:

• Transcriptomic analysis of white blood cells from Merino sheep experimentally exposed to MAP.
• Repeated sampling over the subclinical phase to track gene expression changes over time.
• Classification of sheep into diseased (paucibacillary, multibacillary) and resilient groups based on outcomes.
• Validation of microarray findings using quantitative PCR (qPCR).

Main Results:

• Significant gene expression differences were observed in diseased and resilient sheep compared to controls.
• Key differentially regulated gene families include S100 calcium binding, lysozyme, MHC class I and II, and T cell receptor.
• Gene expression patterns suggest adaptations in cellular growth, proliferation, and lipid metabolism in response to MAP exposure.

Conclusions:

• Specific gene expression profiles can serve as biomarkers for MAP exposure and predict disease or resilience outcomes in sheep.
• MAP infection induces significant alterations in host cellular immune mechanisms, impacting various biological pathways.
• Understanding these molecular changes provides insights into paratuberculosis pathogenesis and potential intervention strategies.