Fig. 7.

Skin equivalents with NHK and EBS cells show several intra- and subepidermal splits after 1 mM 4-PBA treatment, as well as perturbed staining patterns of laminin-332 and of integrin β4.

A Skin equivalents with control vs EBS keratinocytes for the epidermal part and control normal human fibroblasts for the dermal part were employed to assess the effect of 4-PBA in a 3D model. Only a few areas of dermo-epidermal detachment are present in the EBS skin equivalents compared to the control skin equivalents, as shown with haematoxylin/ eosin staining. In the 4-PBA treated skin, however, several intra- and subepidermal splits (black arrows) were found, corroborating the adhesion defect. Scale: 100 μm.

B Laminin-332 deposition was irregular and patchy in the NHK, whereas it also stained the suprabasal keratinocytes in the EBS cells. In the 4-PBA treated skin, again, several intra- and subepidermal splits (yellow arrows) were observed. Scale: 100 μm.

C Integrin β4 showed also an irregular and more pronounced, patchy, suprabasal expression in the treated skin equivalents. Thus, 4-PBA treatment perturbs laminin-332 organization, which in turn seems to abrogate strictly polarized expression of integrin α6β4 in basal keratinocytes. The yellow arrows depict intra- and subepidermal splits, present mostly in the 4-PBA treated skin. Scale: 100 μm. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)