Differential Gene Expression of Novel Lamellar Transcripts in Healthy and Laminitic Horses

Laminitis, the structural failure of the specialized tissue that suspends the distal skeleton within the hoof capsule, is a devastating disease that is the second leading cause of both lameness and euthanasia in the horse. Although this disease is a major concern for many hooved livestock species, the etiology is complex and poorly understood. Most transcriptomic research in equine laminitis has focused on the expression of a few known genes and pathways. Previously, we performed a de novo assembly of Illumina whole transcriptome sequencing derived from the lamellar tissue of three horses (one healthy, one acute laminitic case, and one chronic laminitic case). We generated a total of 75,000 transcripts, 30,000 of which did not match annotations in publicly available databases. We validated the structure of a subset of twelve novel transcripts with Sanger sequencing, using the cDNA from one of the RNA-seq samples. However, as the three samples did not have equal read coverage depth in some of the novel loci, we hypothesized that there may be differential expression related to laminitis disease status. Preliminary RT-PCR and gel electrophoresis of three additional lamellar samples has further suggested expression differences. Quantitative PCR of a larger set of samples of both lamellar and blood RNA is currently on-going. The identification of novel loci associated with laminitis may lead to the identification of new diagnostic biomarkers to allow early detection and preventative interventions for laminitis.