Alterations of keratins, involucrin and filaggrin gene expression in canine atopic dermatitis

Canine atopic dermatitis (CAD) is a common allergic skin disease in dogs, associated with a defective epidermal barrier. In this study we investigated the alterations in skin keratinocyte proliferation and differentiation in CAD by quantitative reverse transcription-polymerase chain reaction. Gene expression of keratin (KRT) markers of proliferative and differentiated keratinocytes, together with that of cornified envelope proteins, involucrin (IVL) and filaggrin (FLG), were evaluated. An upregulation of KRT5 and KRT17 in both lesional and non-lesional AD skin was observed (p < 0.05) whereas KRT2e, KRT14, IVL and FLG expression were significantly increased only in lesional AD skin (p < 0.05). Additionally, the expression levels of KRT5, KRT14, KRT17 and IVL in CAD were strongly correlated. In conclusion, the expression of the majority of the studied keratins, as well as IVL and FLG is increased in CAD with close correlation between the proliferative keratins. This is the first report of a correlation of KRT and IVL genes with CAD.