Relevance of using a human microarray to study gene expression in heaves-affected horses

Area of Science:

• Equine respiratory research
• Molecular mechanisms of disease
• Gene expression analysis

Background:

• Environmental factors of equine heaves are known, but molecular underpinnings are unclear.
• Previous gene expression studies used reverse transcription polymerase chain reaction (RT-PCR), limiting the number of genes analyzed.
• The absence of an equine-specific microarray hindered comprehensive gene expression profiling.

Purpose of the Study:

• To evaluate the utility of a human microarray for studying gene expression in horses with heaves.
• To identify differentially expressed genes in peripheral blood and bronchoalveolar lavage fluid (BALF) of affected horses.
• To assess the feasibility of using a non-equine microarray for equine disease research.

Main Methods:

• Gene expression analysis in nucleated cells from peripheral blood and BALF of heaves-affected horses and controls.
• Utilized a commercially available human microarray platform.
• Validated a subset of differentially expressed genes using real-time quantitative RT-PCR (RT-QPCR).

Main Results:

• Identified 46 candidate genes with a four-fold change in expression between heaves-affected horses and controls.
• Real-time RT-QPCR confirmed some microarray findings.
• The human microarray failed to detect Interleukin (IL)-1beta and IL-8 mRNA in BALF, despite confirmation by RT-QPCR.

Conclusions:

• A human microarray can identify candidate genes involved in equine heaves.
• Limitations exist, including the inability to detect all relevant genes (e.g., IL-1beta, IL-8).
• A complete gene expression profile for heaves could not be achieved using the human microarray alone.