Expression of Notch receptors, ligands and downstream target genes in epidermis of hypertrophic scar

Abstract

To study the expression of Notch receptors, ligands and downstream target genes in hypertrophic scar and normal skin, and to investigate its role in the development of hypertrophic scar. By immunohistochemistry, the expression of epidermal differentiation markers- beta1 integrin, keratin 14 (K14) and keratin 19 (K19), as well as Notch 1-4 and Jagged1 were examined in hypertrophic scars and normal skins. The expression of Notch downstream genes- P21 and P63 was analyzed with real-time quantitative PCR and immunohistochemistry staining. Histological analysis revealed a significant epidermal thickening in the hypertrophic scars, with excessive cell layers above the basal layer. Compared to the normal epidermis, the expression of beta1 integrin, K19 and K14 decreased in hypertrophic scars (P <0.05). Positive expression rate of Notch1 and Jagged1 in keratinocytes was significantly higher in hypertrophic scar than in normal skin (P < 0.05), while there was no difference in Notch2 and 3 positive expression rate. Furthermore, the expression of P21 was significantly up-regulated, while the expression of P63 was down-regulated in keratinocytes of hypertrophic scar (P < 0.05). Notch signal may play an important role in hypertrophic scar pathogenesis. Over-differentiation of Keratinocytes in hypertrophic scar may be related to the overexpression of Notch1 and Jagged1, up-regulation of P21 gene and down-regulation of P63 gene.