S. Huth

Ablative non-sequential fractional ultrapulsed CO2 laser pretreatment improves conventional photodynamic therapy with methyl aminolevulinate in a novel human in vitro 3D actinic keratosis skin model.

The primary trigger of polymorphic light eruption (PLE) remains to be uncovered. We hypothesize that PLE may be initiated by elements resulting from UV-induced damage to microbial communities of the skin, leading to a cascade of events eventually resulting in the skin rash of the disease. One mechanism by which epidermal injury by UV radiation could trigger PLE are danger signals such as damage or pathogen associated molecular patterns DAMP/PAMPs or commensalassociated molecular patterns (CAMPs). Such triggers could be produced due to UV-induced stress on microbial communities of the skin and exacerbate inflammatory responses by inducing the innate immune system through antimicrobial peptides (AMPs) such as psoriasin, RNase7, HBD-2 and LL-37. These AMPs also actively take part in initiating adaptive immunity. That signals derived from microbial rather than human elements may initiate PLE is supported by series of observations, including the PLE-protective effect of topically applied microbial-derived DNA repair enzymes.

Inter-α-trypsin inhibitor heavy chain 5 (ITIH5) is overexpressed in inflammatory skin diseases and affects epidermal morphology in constitutive knockout mice and murine 3D skin models.

Inter‐α‐trypsin inhibitors are protease inhibitors that are thought to be important regulators in various acute‐phase processes. They are composed of one light chain (bikunin) and different heavy chains (ITIHs). The only function known so far of ITIHs is the covalent linkage to hyaluronan (HA). As there is virtually no knowledge on the distribution and function of ITIH proteins in skin tissue, we performed a systematic characterization of ITIH expression in healthy and diseased skin. Using GeneChip® Human Exon 1.0 ST expression profiling, we found that ITIH5 represents the major ITIH family member expressed in human skin. Moreover, the use of quantitative reverse transcription PCR and a customized ITIH5‐specific antibody indicated that ITIH5 is predominantly produced by dermal fibroblasts. Immunohistochemical analysis revealed a clearly detectable ITIH5 protein expression in normal skin. Interestingly, ITIH5 expression was significantly up‐regulated in inflammatory skin diseases. Furthermore, 3D skin models employing murine Itih5−/− epidermal keratinocytes and dermal fibroblasts as well as skin specimens of Itih5−/− mice revealed a significantly altered epidermal structure compared to wild‐type controls. Hence, we can strengthen the presumption that ITIH5 may constitute a novel regulatory molecule of the human skin that could play an important role in inflammation via its interaction with HA.

ITIH5 mediates epigenetic reprogramming of breast cancer cells

BackgroundExtracellular matrix (ECM) is known to maintain epithelial integrity. In carcinogenesis ECM degradation triggers metastasis by controlling migration and differentiation including cancer stem cell (CSC) characteristics. The ECM-modulator inter- α-trypsin inhibitor heavy chain family member five (ITIH5) was recently identified as tumor suppressor potentially involved in impairing breast cancer progression but molecular mechanisms underlying its function are still elusive.MethodsITIH5 expression was analyzed using the public TCGA portal. ITIH5-overexpressing single-cell clones were established based on T47D and MDA-MB-231 cell lines. Colony formation, growth, apoptosis, migration, matrix adhesion, traction force analyses and polarization of tumor cells were studied in vitro. Tumor-initiating characteristics were analyzed by generating a metastasis mouse model. To identify ITIH5-affected pathways we utilized genome wide gene expression and DNA methylation profiles. RNA-interference targeting the ITIH5-downstream regulated gene DAPK1 was used to confirm functional involvement.ResultsITIH5 loss was pronounced in breast cancer subtypes with unfavorable prognosis like basal-type tumors. Functionally, cell and colony formation was impaired after ITIH5 re-expression in both cell lines. In a metastasis mouse model, ITIH5 expressing MDA-MB-231 cells almost completely failed to initiate lung metastases. In these metastatic cells ITIH5 modulated cell-matrix adhesion dynamics and altered biomechanical cues. The profile of integrin receptors was shifted towards β1-integrin accompanied by decreased Rac1 and increased RhoA activity in ITIH5-expressing clones while cell polarization and single-cell migration was impaired. Instead ITIH5 expression triggered the formation of epithelial-like cell clusters that underwent an epigenetic reprogramming. 214 promoter regions potentially marked with either H3K4 and /or H3K27 methylation showed a hyper- or hypomethylated DNA configuration due to ITIH5 expression finally leading to re-expression of the tumor suppressor DAPK1. In turn, RNAi-mediated knockdown of DAPK1 in ITIH5-expressing MDA-MB-231 single-cell clones clearly restored cell motility.ConclusionsOur results provide evidence that ITIH5 triggers a reprogramming of breast cancer cells with known stem CSC properties towards an epithelial-like phenotype through global epigenetic changes effecting known tumor suppressor genes like DAPK1. Therewith, ITIH5 may represent an ECM modulator in epithelial breast tissue mediating suppression of tumor initiating cancer cell characteristics which are thought being responsible for the metastasis of breast cancer.

Effects of a ceramide-containing water-in-oil ointment on skin barrier function and allergen penetration in an IL-31 treated 3D model of the disrupted skin barrier

Atopic dermatitis (AD) is a chronically relapsing, pruritic inflammation of the skin with dryness and disturbed skin barrier function. Recently, we established that IL‐31 treatment of human 3D skin models resulted in a disrupted skin barrier phenotype resembling AD. In this model, we found that IL‐31 interferes with the differentiation of keratinocytes and inhibits the expression of terminal differentiation markers. In the present study, we investigated the effects of a ceramide‐containing water‐in‐oil skin care ointment on the physical skin barrier structure and function in disrupted skin barrier models, generated either by using primary normal human epidermal keratinocytes (NHEK) or HaCaT cells. We observed that the physical skin barrier of the models recovered after daily topical treatment with the ceramide‐containing ointment. Topical application of the ointment prevented downregulation of filaggrin and disorganization of other differentiation markers, such as keratin 10 and β4‐integrin, as demonstrated by immunohistological analysis. The expression of Ki67 was also upregulated in response to the ointment. Furthermore, functional studies revealed that local application of the ointment diminished the increased uptake of fluorescently labelled recombinant allergens of timothy grass (phl p1) in our model. In conclusion, our data revealed that topical application of a ceramide‐containing skin care ointment reduced IL‐31 induced impairments of the physical skin barrier and skin barrier function in an in vitro model of the disrupted skin barrier. This standardized model can be utilized in the future to monitor ex vivo effects of various topical therapies on skin morphology, physiology, and gene expression.