Project description:Background: Infrared A radiation (IRA 760-1440 nm) is a major component of solar radiation and, similar to ultraviolet (UV) radiation, causes photoaging of human skin by increasing the expression of matrixmetalloproteinase-1 (MMP-1) expression in human skin fibroblasts. This gene-regulatory effect resulted from the IRA induced activation of the pleiotropic MAPKinase ERK1/2 signaling pathway, indicating that the IRA response extends beyond MMP-1. In the present study we have therefore assessed the IRA-induced transcriptom in primary human skin fibroblasts. Results: Microarray analysis revealed 599 transcripts to be regulated by physiologically relevant doses of IRA in primary human skin fibroblasts. The IRA induced transcriptom differed from changes known to be induced by UVB or UVA radiation in the same cell type. IRA responsive genes include four categories: extracellular matrix, calcium homeostasis, stress signaling, and apoptosis. These results were confirmed by realtime PCR experiments analyzing thirteen of these genes representing these four categories. By means of chemical inhibitors of known signaling pathways we next show that besides ERK1/2, the p38-, JNK-, PI3K/AKT-, STAT3-, and IL-6 as well as calcium mediated signaling pathways are functionally involved in the IRA gene response and that a major part of it is triggered by mitochondrial, and to a lesser extent non-mitochondrial production of reactive oxygen species. Conclusion: This study identifies IRA radiation as a potent modulator of gene expression in human skin cells. The IRA response is specific and involves genes which are of critical importance for the homeostasis of human skin. Our data confirm the previous notion that IRA contributes to premature skin aging and indicate that further biological effects may result from IRA exposure of human skin. To identify genes differentially regulated after IRA irradiation we analyzed a set of nine independent samples pairs (IRA irradiated vs. sham irradiated), using human primary human dermal fibroblasts from three different donors (termed F1 to F3). Cells between passage number five to ten were exposed in vitro to a dose of 860 J/cm2 IRA. IRA irradiation lasted 40 min leading to a total dose of 860 J/cm2. The culture dishes were placed on a cooled plate connected to thermostated bath (Thermo Haake GmbH, Karlsruhe, Germany) to maintain temperatures below 37°C during IRA irradiation. For irradiation, medium was replaced by phosphate-buffered saline (37°C, Gibco). Control cells (sham) were held on a 37°C thermostated plate under similar conditions without irradiation. Following the treatment cells were cultivated for 24 hours with serum free MEM culture medium at 37°C.

Project description:Transcriptional profiling of Homo sapiens inflammatory skin diseases (whole skin biospies): Psoriasis (Pso), vs Atopic Dermatitis (AD) vs Lichen planus (Li), vs Contact Eczema (KE), vs Healthy control (KO) In recent years, different genes and proteins have been highlighted as potential biomarkers for psoriasis, one of the most common inflammatory skin diseases worldwide. However, most of these markers are not psoriasis-specific but also found in other inflammatory disorders. We performed an unsupervised cluster analysis of gene expression profiles in 150 psoriasis patients and other inflammatory skin diseases (atopic dermatitis, lichen planus, contact eczema, and healthy controls). We identified a cluster of IL-17/TNFα-associated genes specifically expressed in psoriasis, among which IL-36γ was the most outstanding marker. In subsequent immunohistological analyses IL-36γ was confirmed to be expressed in psoriasis lesions only. IL-36γ peripheral blood serum levels were found to be closely associated with disease activity, and they decreased after anti-TNFα-treatment. Furthermore, IL-36γ immunohistochemistry was found to be a helpful marker in the histological differential diagnosis between psoriasis and eczema in diagnostically challenging cases. These features highlight IL-36γ as a valuable biomarker in psoriasis patients, both for diagnostic purposes and measurement of disease activity during the clinical course. Furthermore, IL-36γ might also provide a future drug target, due to its potential amplifier role in TNFα- and IL-17 pathways in psoriatic skin inflammation. In recent years, different genes and proteins have been highlighted as potential biomarkers for psoriasis, one of the most common inflammatory skin diseases worldwide. However, most of these markers are not psoriasis-specific but also found in other inflammatory disorders. We performed an unsupervised cluster analysis of gene expression profiles in 150 psoriasis patients and other inflammatory skin diseases (atopic dermatitis, lichen planus, contact eczema, and healthy controls). We identified a cluster of IL-17/TNFα-associated genes specifically expressed in psoriasis, among which IL-36γ was the most outstanding marker. In subsequent immunohistological analyses IL-36γ was confirmed to be expressed in psoriasis lesions only. IL-36γ peripheral blood serum levels were found to be closely associated with disease activity, and they decreased after anti-TNFα-treatment. Furthermore, IL-36γ immunohistochemistry was found to be a helpful marker in the histological differential diagnosis between psoriasis and eczema in diagnostically challenging cases. These features highlight IL-36γ as a valuable biomarker in psoriasis patients, both for diagnostic purposes and measurement of disease activity during the clinical course. Furthermore, IL-36γ might also provide a future drug target, due to its potential amplifier role in TNFα- and IL-17 pathways in psoriatic skin inflammation.

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Homo sapiens

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