Type 2 Helper T-Cell Cytokines Induce Morphologic and Molecular Characteristics of Atopic Dermatitis in Human Skin Equivalent

Abstract

Both the immune system and the epidermis likely have an important role in the pathogenesis of atopic dermatitis (AD). The objective of the present study was to develop a human skin equivalent model exhibiting morphologic and molecular characteristics of AD in a controlled manner. Skin equivalents generated from normal adult human keratinocytes were stimulated with type 2 T-helper cell (Th2) cytokines IL-4 and IL-13, and morphologic features and gene expression of the epidermis were studied. Th2 cytokines induced intercellular edema similar to spongiotic changes observed in lesional AD as assessed at histopathologic analysis and electron microscopy. Furthermore, genes known to be specifically expressed in epidermis of patients with AD such as CAII and NELL2 were induced. In contrast, expression of psoriasis-associated genes such as elafin and hBD2 was not changed. Th2 cytokines caused DNA fragmentation in the keratinocytes, which could be inhibited by the caspase inhibitor Z-VAD, which suggests that apoptosis was induced. In addition, up-regulation of the death receptor Fas was observed in keratinocytes after Th2 cytokine stimulation. IL-4 and IL-13 induced phosphorylation of the signaling molecule STAT6. It was concluded that the skin equivalent model described herein may be useful in investigation of the epidermal aspects of AD and for study of drugs that act at the level of keratinocyte biology.

Methyl‐β‐cyclodextrin concurs with interleukin (IL)‐4, IL‐13 and IL‐25 to induce alterations reminiscent of atopic dermatitis in reconstructed human epidermis

“…1a). Conversely, RHE treated with IL-4, IL-13 and IL-25 for 48 hours displayed intercellular space widening similar to spongiosis (already reported for IL-4 and IL-13 [4][5][6] ) and hypogranulosis, two histological hallmarks of lesional AD skin (Fig. S2).…”

Coal tar induces AHR-dependent skin barrier repair in atopic dermatitis

“…Th2 cytokines like IL-4 and IL-13 induce spongiosis and apoptosis in skin equivalents, probably via STAT6 signaling (18). These cytokines were also shown to downregulate involucrin and loricrin expression via STAT6 (4).…”

“…Our results reveal a key role of the AHR signaling pathway in breaching the vicious The immunopathogenesis of AD has been studied directly on patients or in animal models based on allergic immune responses (29)(30)(31). We have recently developed in vitro organotypic models for psoriasis and AD (18,19), and have shown that the application of genetic techniques in these models could be used to study epidermal aspects of diseases (32). Others showed that FLG knockdown in human skin equivalents could mimic AD skin by impaired epidermal differentiation and barrier dysfunction (33,34).…”

“…Next, we used an organotypic human skin model (hereinafter referred to as "skin equivalents") to evaluate the effects of coal tar during epidermal morphogenesis. We have previously shown that skin equivalents can be used successfully to mimic many aspects of normal epidermis or diseased epidermis (e.g., psoriasis and AD) (18,19). After 3 days of submerged culture, the skin equivalents were lifted at the air-liquid interface and the culture medium was supplemented with coal tar.…”

The Effects of Human Beta-Defensins on Skin Cells in vitro

“…We have previously described the use of in vitro human skin equivalents to study skin biology and inflammation [20,21,[24][25][26][27] . We here took a transgenic approach to selectively overexpress hBD2 or hBD3, using lentiviral gene delivery in primary keratinocytes as we have described previously [25] .…”