[Use of 2D and 3D cell cultures in dermatology]. / Einsatz von 2-D- und 3-D-Kulturen in der Dermatologie.

The skin is a complex organ that performs a number of vital functions, including forming a physical barrier that protects our body from the penetration of pathogens and irritants and from excessive transepidermal water loss. In addition to its passive properties, the skin is also actively involved in the immune process. A complex structure of different cell types and structures allows the skin to fulfil these functions. In vitro research often faces the problem that simple 2D cell cultures are not able to adequately map these functions. Here 3D skin models offer a possible solution. In recent years, there has been significant development in this field; the reproducibility of the method as well as the physiological structure and tissue architecture of the 3D skin models have been improved. Depending on the research question, protocols for 3D skin models have been published, ranging from simple multilayer epidermis models to highly complex vascularized 3D full skin models.

RNase 7 downregulates TH2 cytokine production by activated human T cells.

BACKGROUND: The antimicrobial peptide (AMP) RNase 7 is constitutively expressed in the epidermis of healthy human skin and has been found to be upregulated in chronic inflammatory skin diseases such as atopic dermatitis and psoriasis. Activated T cells in lesional skin of patients with atopic dermatitis (AD) and psoriasis (PSO) might be directly exposed to RNase 7. In addition to their antimicrobial activity, immunoregulatory functions have been published for several AMPs. In this study, we investigated immunoregulatory effects of the antimicrobial peptide RNase 7 on activated T cells. METHODS: Isolated human CD3+T cells were stimulated with RNase 7 and screened for possible effects by mRNA microarray analysis. The results of the mRNA microarray were confirmed in isolated CD4+T cells and in polarized TH2 cells using skin-derived native RNase 7 and a recombinant ribonuclease-inactive RNase 7 mutant. Activation of GATA3 was analysed by electrophoretic mobility shift assay. RESULTS: Treatment of activated human CD4+T cells and TH2 cells with RNase 7 selectively reduced the expression of TH2 cytokines (IL-13, IL-4 and IL-5). Experiments with a ribonuclease-inactive recombinant RNase 7 mutant showed that RNase 7 ribonuclease activity is dispensable for the observed regulatory effect. We further demonstrate that CD4+T cells from AD patients revealed a significantly less pronounced downregulation of IL-13 in response to RNase 7 compared to healthy control. Finally, we show that GATA3 activation was diminished upon cultivation of T cells with RNase 7. CONCLUSION: Our data indicate that RNase 7 has immunomodulatory functions on TH2 cells and decreases the production of TH2 cytokines in the skin.

Expression of interleukin (IL)-1 family members upon stimulation with IL-17 differs in keratinocytes derived from patients with psoriasis and healthy donors.

BACKGROUND: A number of studies have challenged the T-cell-centred pathogenetic view of psoriasis by the finding that epithelium-expressed genes are intimately involved in the inflammatory process. Interleukin (IL)-17 is an important inflammatory mediator in skin psoriasis. OBJECTIVE: IL-17 is known to act on keratinocytes and we were interested in its impact on the expression of pro- and anti-inflammatory IL-1 family members. METHODS: We compared human keratinocytes derived from epidermal stem cells of hair follicles plucked from patients with psoriasis and healthy individuals using quantitative reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assays. RESULTS: In the presence of IL-17, psoriasis-derived keratinocytes showed a significantly higher induction of the proinflammatory IL-1 family members IL-1F6 and IL-1F9, but not of anti-inflammatory members IL-1F5, IL-1F7 or IL-1F3 compared with keratinocytes from healthy individuals. Both basal and IL-17-induced levels of IL-1F2 and IL-1F1 were found to be significantly lower in psoriasis keratinocytes. CONCLUSION: As keratinocytes were derived from epidermal stem cells of the hair follicles and were obtained from nonlesional sites, differences found are likely to present an intrinsic feature of psoriasis epithelium. Our data support the significance of IL-1 family members as therapeutic targets in psoriasis conditions.