Project description:Exposure to UVB irradiation results in multitude of cellular responses including generation of reactive oxygen species (ROS) and DNA damage and is responsible for non-melanoma skin cancers (NMSCs). Although genetic mutation is well documented, the epi-mutation, the alteration in epigenetics, remains elusive. DNA methylation is a stable and heritable epigenetic change in the control of gene expression. Furthermore, it is unclear how the epigenomic DNA methylome would change during progression of UVB-induced carcinogenesis. In this study, we utilized CpG Methyl-seq to identify a genome-wide DNA CpG methylation, to profile the DNA methylation in ultraviolet B (UVB)-irradiated SKH-1 mouse skin epidermis and non-melanoma skin papillomas at various stages. Agilent mouse SureSelect Methyl-seq Kit was used for enrichment of about 3.3 million CpG sites in the mouse genome. Simultaneously, RNA-seq was performed to examine the corresponding transcriptome alterations. Bioinformatic analysis was utilized to identify differentially methylated and differentially expressed genes. The methylation profiles in mouse epidermis were altered by UVB-irradiation as time progresses. Comparing all epidermis samples at week-15 versus week-25, UVB had great impact on DNA methylome alteration. Examination of the differentially methylated regions (DMRs), most of the DMRs were located in the distal intragenic (>3 kb upstream of TSS or downstream of 3’ UTR) and the promoter regions. Interestingly, at week-25 the methylation profiles between the whole skin versus the tumor samples were different. Ingenuity Pathways Analysis (IPA) identified many cancer related pathways including PTEN, p53, Nrf2 and inflammatory signaling in UVB-irradiation induced carcinogenesis. Cell cycle regulation and cell growth related pathways including State3 signaling and estrogen-mediated S-phase entry were also identified. Additionally, some novel genes involved in skin carcinogenesis that were not previously reported were differentially methylated, including Enf2, Mgst2, Vegfa, and Cdk4. The methylation and expression of these genes were validated by pyrosequencing and qPCR. Taken together, the current study provides novel profiles of methylation and transcriptomic changes at different stages of carcinogenesis in UVB-irradiation induced NMSC and offer potential targets for prevention and treatment of NMSC at different stages of human skin cancer.

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:Renin-angiotensin system regulates cell proliferation, differentiation, apoptosis and tissue remodeling in skin. Previouly, we reported that angiotensin-converting enzyme (ACE) expression and angiotensin II level were enhanced by repeated UVB-irradiation of hairless mice skin, and ACE inhibitor enalapril maleate accelerated recovery of UVB-induced wrinkle. In present study, we analyzed gene expression with DNA microarray and protein distribution with immunofluorecence method to clarify the process of wrinkle repairing with enalapril maleate in UVB-irradiated hairless mouse. In microarray analysis, we detected up-regulation of various extracullular matrix (ECM) genes and ECM related genes. In immunofluorescence, we confirm that type 1 collagen, fibrillin1, elastin, and dystroglycan 1 were decreased by repeated UVB-irradiation and the distribution of these components were improved by enalapril maleate treatment. In addition, ADAMTS2 and MMP-14, these were perticipate in ECM structure formation and degradation, were increased in enalapril maleate-treated mouse skin. While the functions of these molecules in skin is not clear yet, it is suggested that these molecules participate in improvement of wrinkles induced by UVB-irradiation. Male hairless mice of the SKH-1 strain were purchased from Charles River Laboratories Japan, Inc. (Tokyo, Japan). These animals were approximately 6 weeks old at the start of the experiment. They were fed a commercial diet (CRF-1, Oriental Yeast Co., Ltd, Tokyo, Japan) ad libitum and allowed free access to water. The dorsal region of the mouse was repeatedly irradiated with UVB for 10 weeks. Enalapril maleate treatment was started at 1 week after 10-week irradiation. One hundred microliters of 1% w/v enalapril maleate dissolved in 30 vol % ethanol solution or 30 vol % ethanol (control) was applied 5 times a week for 2 consecutive weeks to the whole dorsal skin of each of the mice. All experimental procedures using mice were approved by the Animal Experiment Committee of Tokyo University of Agriculture and Technology (approval number 24-82). The dosal region of the mouse was repeatedly irradiated with UVB for 10 weeks. Enalapril maleate treatment was started at 1 week after 10-week irradiation. One hundred microliters of 1% w/v enalapril maleate dissolved in 30 vol % ethanol solution or 30 vol % ethanol (control) was applied 5 times a week for 2 or 6 consecutive weeks to the whole dorsal skin of each of the mice. Each of the experimental groups comprised 6 mice. After 2- or 6-week drug treatment, skin samples were collected for microarray analysis.

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Differentially expressed genes induced by UVB stimulation between the P2ry6+/+ and P2ry6-/- mice

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