Transcriptional changes associated with recurrent airway obstruction in affected and unaffected horses.
OBJECTIVE
To identify differentially expressed genes in pulmonary tissues of horses affected with summer pasture-associated obstructive pulmonary disease (SPAOPD), which is a form of recurrent airway obstruction (RAO), compared with those of unaffected horses.


METHODS
6 horses with SPAOPD-RAO and 6 unaffected (healthy) horses.


METHODS
Horses were assigned to 2 groups on the basis of medical history, clinical score, and transpleural pressure. Total RNA from each of the 5 lung lobes of each of the 6 SPAOPD-RAO-affected horses was extracted and pooled. Similarly, total RNA from unaffected horses was pooled. Differential display (DD) PCR assay was performed, and differentially expressed bands were purified and cloned into a plasmid vector. Plasmids were extracted from recombinant colonies, and purified DNA was sequenced. Genes of interest for RAO pathogenesis were identified. Real-time PCR assay was performed to confirm findings for the DD PCR assay.


RESULTS
18 differentially expressed genes (17 upregulated and 1 downregulated) were identified. Three genes of particular interest were found to be altered (2 upregulated and 1 downregulated) in horses with SPAOPD-RAO by use of real-time PCR assay, and these findings matched the differential expression found by use of the DD PCR assay.


CONCLUSIONS
SPAOPD-RAO in horses is a multifactorial, complex disease involving several genes. Upregulated genes, particularly beta2-microglobulin, and the downregulated secretoglobin gene can serve as marker genes that may help to identify SPAOPD-RAO at an early age.
Venugopal
Changaram S
CS
Equine Health Studies Program, Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA. cvenugopal@vetmed.lsu
Mendes
Luiz Claudio N
LC
Peiró
Juliana R
JR
Laborde
Susan S
SS
Stokes
Ashley M
AM
Moore
Rustin M
RM
D000818:Animals; D020869:Gene Expression Profiling / Q000662:veterinary*; D006734:Horse Diseases / Q000378:metabolism*; D006736:Horses; D008168:Lung / Q000378:metabolism; D008173:Lung Diseases, Obstructive / Q000378:metabolism / Q000662:veterinary*; D014158:Transcription, Genetic / Q000502:physiology*