Gene expression in canine atopic dermatitis and correlation with clinical severity scores.
BACKGROUND
Canine atopic dermatitis (cAD) is a common condition in dogs that may be a naturally occurring model for human atopic dermatitis (hAD). Despite this, comparative research is limited, particularly into the genetic background of cAD.


OBJECTIVE
1. Measure candidate gene expression in cAD skin using quantitative real time PCR (qPCR). 2. Correlate gene expression to clinical cAD scores (Canine Atopic Dermatitis Extent and Severity Index[CADESI]-03 and intradermal allergen test [IDT]).


METHODS
mRNA was extracted from biopsies of non-lesional and lesional skin from atopic dogs, and healthy skin from non-atopic dogs. Gene expression was quantified using qPCR, and compared between non-lesional atopic, lesional atopic and healthy skin. Gene expression in atopic skin was correlated with clinical severity (CADESI-03) and the number of positive reactions on an IDT.


RESULTS
Of the 20 quantified genes, 11 demonstrated statistically significant altered mRNA expression between atopic and healthy skin; dipeptidyl-peptidase-4 (DPP4), phosphatidylinositol-3,4,5-trisphosphate-5-phosphatase-2 (INPPL1), serine protease inhibitor kazal type-5 (SPINK5), sphingosine-1-phosphate lyase-1 (SGPL1), peroxisome proliferator-activated receptor gamma (PPARgamma), S100 calcium-binding protein A8 (S100A8), Plakophilin-2 (PKP2), Periostin (POSTN), Cullin4A, TNF-alpha and metalloproteinase inhibitor-1 (TIMP-1). Three genes correlated with CADESI-03: serum amyloid A 1 (SAA-1), S100A8, and PKP2; and four with IDT results: mast cell protease I (CMA1), SAA-1, S100A8 and SPINK5.


CONCLUSIONS
Genes with altered expression included those relevant to skin barrier formation and immune function, suggesting both are relevant in the pathogenesis of AD. Many of these genes reflect the proposed pathogenesis in hAD, supporting the use of dogs as a model for hAD. Furthermore, these genes may be considered suitable targets for future genetic and protein function studies in human and canine AD.
Wood
Shona H
SH
Department of Veterinary Pathology, Faculty of Veterinary Science, University of Liverpool, Liverpool, UK. shona.wood@liv.ac.uk
Clements
Dylan N
DN
Ollier
William E
WE
Nuttall
Tim
T
McEwan
Neil A
NA
Carter
Stuart D
SD
D000485:Allergens / Q000276:immunology; D000818:Animals; D001483:Base Sequence; D003876:Dermatitis, Atopic / Q000235:genetics* / Q000276:immunology / Q000662:veterinary*; D004195:Disease Models, Animal; D004283:Dog Diseases / Q000235:genetics* / Q000276:immunology; D004285:Dogs; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D012720:Severity of Illness Index; D012867:Skin / Q000276:immunology; D012882:Skin Tests
D000485:Allergens; D012333:RNA, Messenger