GENE EXPRESSION IN LAMINITIS
Use of laser capture microdissection for the assessment of equine lamellar basal epithelial cell signalling in the early stages of laminitis.
BS Leise, MR Watts, S Roy, AS Yilmaz, H Alder and JK Belknap
Laser capture microdissection allows specific cells to be dissected from a tissue sample under microscopic guidance. This study utilised this technology to allow a highly purified population of laminar basal epithelial cells to be collected from lamellar biopsies in a carbohydrate (CHO) induced laminitis model. Eight horses were subjected to carbohydrate overload, lamellar biopsies were taken from the left forefoot prior to administration of carbohydrates, to act as a control group. Further lamellar biopsies were taken from the other feet at the onset of fever (or 24 hours post CHO administration) and the onset of Obel grade 1 lameness (or 48 hours post CHO administration). Laser capture microdissection was then used to isolate laminar basal epithelial cells, RNA sequencing and profiling then allowed the difference in lamellar gene expression profiles to be compared before, during and after the onset of laminitis. Forty genes were expressed differently (22 up-regulated, 18 down-regulated) at the time of development of laminitis, compared with before. One hundred and seven genes were expressed differently at the time of development of Obel grade 1 lameness, compared with before CHO administration. Genes related to the inflammatory response and extracellular matrix regulation were significantly altered at the time of laminitis development, and onset of clinical signs.
The bottom line: Altered gene expression in lamellar basal epithelial cells during the development and onset of laminitis shows that this cell is an active participant in the structural failure of lamellae during clinical laminitis.
Photo: Equine Veterinary Journal19 AUG 2014 DOI: 10.1111/evj.12283