Project description:This study investigates the effect of ZAKalpha kinase in UVB-triggered signaling in an immortalized keratinocyte cell line N/TERT-1. The experiments compared sham-irradiated and UVB-irradiated isogenic Cas9 control and ZAK KO cells in order to define which UVB responsive transcripts are controlled by ZAKalpha.
Project description:To address CPD-dependent UVB activities, a model system was established in which transfection of keratinocytes with pseudouridine-modified mRNA (M-NM-(-mRNA) encoding CPD-photolyase resulted in 90% reduction of CPDs within 6 and 24 hours after UVB exposure. Microarray analysis of this model system demonstrated that more than 50 % of the gene expression altered by UVB were changed in a CPD-dependent manner. The expression of most of the CPD-dependent genes was changed at 6 h after UVB as compared to 24 h likely due to the higher CPD levels. Nine genes (ATF3, CCNE1, CDKN2B, EGR1, ID2, PTGS2, RUNX1, SNAI1, SNAI2) regulated by CPDs were selected for further investigation (qPCR, Western blot) based on the microarray data. Gene expression modulated by UVB irradiation in HaCaT keratinocytes was measured at 6 and 24 hours after the exposure to dose of 20 mJ/cm2 UVB. Three independent experiments were performed at each time (6 or 24 hours) using different passages for each experiment.
Project description:To address CPD-dependent UVB activities, a model system was established in which transfection of keratinocytes with pseudouridine-modified mRNA (Ψ-mRNA) encoding CPD-photolyase resulted in 90% reduction of CPDs within 6 and 24 hours after UVB exposure. Microarray analysis of this model system demonstrated that more than 50 % of the gene expression altered by UVB were changed in a CPD-dependent manner. The expression of most of the CPD-dependent genes was changed at 6 h after UVB as compared to 24 h likely due to the higher CPD levels. Nine genes (ATF3, CCNE1, CDKN2B, EGR1, ID2, PTGS2, RUNX1, SNAI1, SNAI2) regulated by CPDs were selected for further investigation (qPCR, Western blot) based on the microarray data.
Project description:In response to UVB irradiation, human keratinocytes transiently block cell cycle progression to allow ample time for DNA repair and cell fate determination. These cellular processes are important for evading the initiation of carcinogenesis in skin. We previously showed that repression of mRNA translation initiation through phosphorylation of eIF2α (eIF2α-P) protects keratinocytes from UVB-induced apoptosis. In this study, we elucidate the mechanism of eIF2α-P cytoprotection in response to UVB. Loss of eIF2α-P induced by UVB diminished G1 arrest, DNA repair rate, and cellular senescence coincident with enhanced cell death in human keratinocytes. Genome-wide translation analyses revealed that the mechanism for these critical changes directed by eIF2α-P involved induced expression of CDKN1A encoding p21 protein. p21 is a major regulator of the cell cycle, and we show that human CDKN1A mRNA splice variant 4 is preferentially translated by eIF2α-P during stress in a mechanism mediated in part by upstream ORFs situated in the 5’-leader of CDKN1A mRNA. We conclude that eIF2α-P is cytoprotective in response to UVB by a mechanism featuring translation of a specific splice variant of CDKN1A that facilitates G1 arrest and subsequent DNA repair.
Project description:Background: Atopic dermatitis (AD) is a common inflammatory skin disease with broad impact on quality of life and on the health care system. The pathophysiology is not fully understood, but it is likely multifactorial involving immune dysfunction, altered skin barrier and environmental factors. Narrow band ultraviolet B (nb-UVB) treatment leads to normalization of the tissue and clinical improvement. However, knowledge of early changes in AD skin in response to nb-UVB is lacking and could provide important clues to decipher the disease mechanisms and potential new treatment targets. Objective: To map the early transcriptional changes in the skin in response to nb-UVB treatment. Results: When examining the early response after only three local UVB-treatments, gene expression analysis revealed 30 down- and 47 up-regulated transcripts. Among these only a small proportion were related to the inflammatory response. Interestingly, two cytokines of the interleukin (IL)-1 family were differentially expressed: the proinflammatory cytokine IL-36γ was reduced after treatment, while the anti-inflammatory cytokine IL-37 increased in skin after treatment with nb-UVB. Conclusion: Local nb-UVB induced an early decrease of the pro-inflammatory cytokine IL-36γ and an increase of the anti-inflammatory IL-37. This likely represents one of the first changes in inflammatory signaling induced by nb-UVB in atopic eczema.
Project description:Unprotected exposure to UVB radiation from the sun and the resulting DNA damage are thought to be responsible for physiological changes in the skin and for a variety of skin cancers, including basal cell and squamous cell carcinoma and malignant melanoma. Although the mutagenic effects of UVB have been well documented and studied mechanistically, there is only limited information as to whether UV light may also be responsible for inducing epigenetic changes in the genome of exposed cells. DNA methylation is a stable epigenetic modification involved in gene control. To study the effects of UVB radiation on DNA methylation, we repeatedly exposed normal human keratinocytes to a UVB light source. After a recovery period, we analyzed global DNA methylation patterns in the irradiated and control cells using the methylated-CpG island recovery assay (MIRA) method in combination with high-resolution microarrays. Bioinformatics analysis revealed only a limited number of possible differences between UVB-exposed and control cells. However, these minor apparent changes could not be independently confirmed by bisulfite sequencing-based approaches. This study reveals that UVB irradiation of keratinocytes has no recognizable global effect on DNA methylation patterns and suggests that changes in DNA methylation, as observed in skin cancers, are not immediate consequences of human exposure to solar UVB irradiation. DNA methylation analysis of control and UVB irradiated keratinocytes. The MIRA assay was used for enrichment of methylated DNA. NimbleGen CpG island plus promoter arrats were used.
Project description:Unprotected exposure to UVB radiation from the sun and the resulting DNA damage are thought to be responsible for physiological changes in the skin and for a variety of skin cancers, including basal cell and squamous cell carcinoma and malignant melanoma. Although the mutagenic effects of UVB have been well documented and studied mechanistically, there is only limited information as to whether UV light may also be responsible for inducing epigenetic changes in the genome of exposed cells. DNA methylation is a stable epigenetic modification involved in gene control. To study the effects of UVB radiation on DNA methylation, we repeatedly exposed normal human keratinocytes to a UVB light source. After a recovery period, we analyzed global DNA methylation patterns in the irradiated and control cells using the methylated-CpG island recovery assay (MIRA) method in combination with high-resolution microarrays. Bioinformatics analysis revealed only a limited number of possible differences between UVB-exposed and control cells. However, these minor apparent changes could not be independently confirmed by bisulfite sequencing-based approaches. This study reveals that UVB irradiation of keratinocytes has no recognizable global effect on DNA methylation patterns and suggests that changes in DNA methylation, as observed in skin cancers, are not immediate consequences of human exposure to solar UVB irradiation.
Project description:The goal of this study was to determine the effect of dexamethasone treatment on trancriptional sigantures and pathways of sarcoidosis monocytes.
Project description:Using microcell-mediated chromosome transfer (MMCT) into the mouse melanoma cell line, B16F10, we have previously found that human chromosome 5 carries a gene, or genes, that can negatively regulate TERT expression. To identify the gene responsible for the regulation of TERT transcription, we performed cDNA microarray analysis using parental B16F10 cells, telomerase negative B16F10 microcell hybrids with a human chromosome 5 (B16F10MH5), and its revertant clones (MH5R) with reactivated telomerase. Here we report the identification of PITX1, whose restoration leads to the downregulation of mouse tert (mtert) transcription, as a TERT suppressor gene. Additionally, both human TERT (hTERT) and mouse TERT (mtert) promoter activity can be suppressed by PITX1. We showed that three and one binding sites, respectively, within the hTERT and mtert promoters that express a unique conserved region are responsible for the transcriptional activation of TERT. Furthermore, we showed that PITX1 binds to the TERT promoter both in vitro and in vivo. Thus, PITX1 suppresses TERT transcription through direct binding to the TERT promoter, which ultimately regulates telomerase activity.
Project description:Previous studies showed that SV40 transformed cells have unique DNA damage responses; further inspecting these responses by microarray provides an opportunity to discover transciprtional insights of DNA damage responses after UVB irradiation. This study is used to comapre to GSE7589, our previous study of human normal lung fibroblast after UVB irradiation. We used a loop design in this study, cDNA microarray experiment consisted of eight RNA samples, including UVB-irradiated samples and their corresponding controls of 4 time points after UV irradiation.