β-catenin expression during the canine epidermal development

Abstract

β-catenin plays a central role both in the adherent intercellular junctions, as well as in the canonical Wnt signalling pathway. The study of the expression pattern of this protein during the canine epidermal development has not been performed. The purpose of this study was to evaluate the immunohistochemical expression pattern of β-catenin on canine samples of prenatal epidermis at different developmental stages using a tissue microarray. β-catenin immunostaining disclosed membrane and cytoplasmic expression in a high number of epidermal cells of the basal, spinous and granulous strata. Furthermore, samples of late stages of epidermal differentiation showed a nuclear expression of β-catenin was observed in a few cells of the granulous stratum. These results support the relevant role that β-catenin plays in the adherent intercellular junction during the normal canine epidermis development. In addition, the nuclear expression of β-catenin in a few highly differentiated granular keratinocytes during the late stages of the epidermal development could be related to the loss of adherent junctions for the stratum corneum formation. In addition, the fact that the nuclear labelling of β-catenin, which is considered a hallmark of activation of the Wnt signalling pathway, was not the dominant expression observed in the fetal epidermis suggests that this signaling pathway does not play a relevant role during the epidermal development in dogs.