Project description:Reactive oxygen species (ROS) induced by ultraviolet B (UVB) cause DNA damage such as 8-oxoguanine (8-oxoG) in mouse skin, with long-term exposure leading skin tumor development. We previously reported that Ogg1 knockout mice, with defective repair enzyme for 8-oxoG oxidatively damaged DNA, showed greater up-regulation of inflammatory response genes and Versican, which encodes a large extracellular matrix proteoglycan, than their wild-type counterparts. Here, we focused on inflammatory response genes associated with Versican up-regulation after UVB exposure, using Ogg1 knockout mouse embryonic fibroblasts (MEFs). Gene profiling among inflammatory response-associated genes in MEFs treated with UVB showed that Cxcl1, a CXC chemokine, was most significantly up-regulated in Ogg1(-/-) MEFs, concomitant with the up-regulation of Versican. We found that Versican targeted siRNA directly regulated Cxcl1, and vice versa, in which the system of up-regulation for these two key genes were controlled by PI3kinase-NFkB activation signaling rather than conventional UV-induced p38 mitogen-activated protein kinase. Furthermore, for the initial process of differentiating inflammatory response between Ogg1(-/-) and Ogg1(+/+), we found that down-regulation of p53 along with anti-apoptotic signal was a key event in Ogg1(-/-).The results of the present study suggest suppression of skin tumor development involving UVB/ROS-induced 8-oxoG formation by targeting genes and signaling pathways.
Project description:Xeroderma pigmentosum type A (XP-A) is a hereditary disease characterized by early onset of skin cancers development by ultraviolet (UV) exposure. Although etiology of susceptible to skin tumor of XP-A is well investigated as a repair deficiency by UV-induced DNA damage, the mechanism of unusual strong and prolonged skin inflammation caused by UV in XP-A and whether UV-induced inflammatory response relates to skin tumor-prone phenotype remains to be elucidated. Among up-regulated inflammatory response related genes in Xpa mice compared with wild-type by gene profiling study, Cxcl1 in Xpa mice was significantly different from wild-type and blood level of Cxcl1 was increased with UVB exposed on even small area of skin in Xpa mice. We administered Cxcl1 neutralizing antibody or antioxidant agent n-acetylcysteine for Xpa mice after UVB irradiation, showing that blood levels of Cxcl1, ear swelling and skin redness as an inflammatory response were significantly suppressed. Xpa mice with chronic UVB exposure and Cxcl1 neutralizing antibody or n-acetylcysteine administered Xpa mice yields much less skin tumors compared with control group. Those results indicate that highly inflammatory response of Xpa mice by UVB plays a role of skin tumor development that could be suppressed by chemokine as Cxcl1 through antioxidant mechanism.
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: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:UV irradiation is a major environmental effector of skin damage and aging. Elevated levels of glycosaminoglycans (GAGs), as measured by Hale’s stain, are seen following cutaneous photodamage. Preliminary data from our lab indicates that this is a complex response involving differential regulation of both GAGs and proteoglycans. Recently, different GAG species have been shown to have distinct effects on the recruitment and activation of immune cells and stimulation of cytokine production (Taylor and Gallo, FASEB, 2006; 20: 9-22). We speculate that the elevated GAGs and proteoglycans observed after ultraviolet B (UVB) irradiation are involved in the inflammatory and healing responses to photodamage. Chondroitin sulfate synthases (CSSs) are not increased by UVB in mice or in cultured human fibroblasts. To determine whether genomic upregulation of CSSs is responsible for the post-UVB CS increase, we measured the dermal expression of CSS1 and CSS3 mRNA in C57Bl6 mice after 5 days of UV-B exposure. Irradiation caused no change in either CSS1 or CSS3 mRNA expression. We also studied CSS RNA expression in cultured human fibroblasts. We compared control cells to cells treated with 30 mJ/cm2 UVB, cells treated with 1 ng/mL IL-1α, and cells co-stimulated with UVB and IL-1α. In vivo, UV-B induces IL-1α production by keratinocytes and inflammatory cells, and this IL-1α interacts with fibroblasts. Co-stimulation with IL-1α + UVB induces TNF-α production by the fibroblasts, mirroring the in vivo interaction. CSS1 mRNA was suppressed 60% and CSS3 mRNA expression dropped 87% relative to sham at 24 hours post-treatment (p<0.001, Dunnet q’). Since CS is not upregulated by its synthases, we postulated an alternative mode of induction whereby one or more CS proteoglycans are transcriptionally increased and bind more CS in the dermis. We used the N-13 goat monoclonal anti-serglycin antibody to visualize changes in cutaneous serglycin content following acute UV-B exposure. Serglycin is one example of CS-binding dermal proteoglycans that is induced by UVB, and there are likely others. Diffuse upper-dermal serglycin staining, like upper-dermal CS, was induced continuously at 24, 48, and 72 hours after irradiation. Serglycin-expressing inflammatory cells are recruited to the dermis following irradiation, peaking at 48 hours post-exposure. A statistically significant 1.70 fold increase in serglycin mRNA was measured in cultured human fibroblasts 6 hours after co-stimulation with UVB and IL-1α. Realtime PCR also revealed a significant 2.04 fold upregulation at 24 hours after co-stimulation, and serglycin was increased 4.63 times 6 hours after Il-1α treatment alone.
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:Hypertrophic scar (HS) considerably affects the appearance and causes tissue dysfunction in patients. Here we show a separating microneedle (MN) consisting of photo-crosslinked GelMA and 5-FuA-Pep-MA prodrug in response to high reactive oxygen species (ROS) levels and overexpression of matrix metalloproteinases (MMPs) in the HS pathological microenvironment. RNA sequencing analyses confirm that drug-loaded MNs could reverse skin fibrosis through down-regulation of BCL-2-associated death promoter (BAD), insulin-like growth factor 1 receptor (IGF1R) pathways, simultaneously regulate inflammatory response and keratinocyte differentiation via up-regulation of toll-like receptors (TOLL), interleukin-1 receptor (IL1R) and keratinocyte pathways.
Project description:Considering that human skin cancer is predominantly attributed to UV radiation from sunlight, additional investigations are needed to elucidate the role of P2RY6 in UVB-induced skin carcinogenesis. Surprisingly, we find that P2ry6 deletion exhibits marked promotion to UVB-induced skin papilloma formation compared with wild-type mice, suggesting its tumor-suppressive role in UVB-induced skin cancer. Additionally, P2ry6 knockout promotes mouse skin hyperplasia induced by short-term UVB irradiation, while UDP, the ligand of P2RY6, can inhibit UVB-induced skin damage. Furthermore, UVB irradiation can significantly upregulate P2RY6 expression in mouse and human skin cells. These results indicate that P2RY6 plays a crucial protective role in resisting UVB-induced skin damage and carcinogenesis. At the molecular level, P2RY6 deletion inhibits ubiquitination and expression of XPC after UVB irradiation in keratinocytes, resulting in the accumulation of CPDs (cyclobutane pyrimidine dimers). P2RY6 deletion also activates PI3K/AKT signaling pathway in vitro and in vivo. The CPD accumulation and inflammatory responses enhanced by P2RY6 deletion are reversed by an AKT inhibitor. These findings suggest that P2RY6 acts as a tumor suppressor in UVB-induced skin cancer by regulating PI3K/AKT signaling pathway.
Project description:While several physiological skin parameters vary in a circadian manner, the identity of genes participating in chronobiology of skin remains unknown, leading us to define the circadian transcriptome of mouse skin at two different stages of the hair cycle, telogen and anagen. The circadian transcriptomes of telogen and anagen skin are largely distinct, with the former dominated by genes involved in cell proliferation and metabolism. The expression of many metabolic genes is antiphasic to cell cycle related genes, the former peaking during the day and the latter peaking at the night. Consistently, accumulation of reactive oxygen species, a byproduct of oxidative phosphorylation, and S-phase are antiphasic to each other in telogen skin. Furthermore, the circadian variation in S-phase is controlled by BMAL1 intrinsic to keratinocytes as keratinocyte-specific deletion of Bmal1 obliterates time of day dependent synchronicity of cell division in the epidermis leading to a constitutively elevated cell proliferation. Consistent with higher cellular susceptibility to UV-induced DNA damage during S phase, we found that mice are most sensitive to UVB-induced DNA damage in the epidermis at night. As maximum numbers of keratinocytes go through S phase in the late afternoon in the human epidermis, we speculate that in humans the circadian clock imposes regulation of epidermal cell proliferation such that skin is at a particularly vulnerable stage during times of maximum UV exposure, thus contributing to the high incidence of human skin cancers. Whole skin was collected at 4 hour intervals for 48 hours. Where ZT number indicates the number of hours elapsed from when lights are switched on. ZT0 = lights on (6am). ZT12=lights off (6pm). Total RNA was purified from the skin of each mouse and equal amount of RNA from the 3 replicates for each time point were pooled. Telogen samples were collected from skin of P46 male mice.
Project description:While several physiological skin parameters vary in a circadian manner, the identity of genes participating in chronobiology of skin remains unknown, leading us to define the circadian transcriptome of mouse skin at two different stages of the hair cycle, telogen and anagen. The circadian transcriptomes of telogen and anagen skin are largely distinct, with the former dominated by genes involved in cell proliferation and metabolism. The expression of many metabolic genes is antiphasic to cell cycle related genes, the former peaking during the day and the latter peaking at the night. Consistently, accumulation of reactive oxygen species, a byproduct of oxidative phosphorylation, and S-phase are antiphasic to each other in telogen skin. Furthermore, the circadian variation in S-phase is controlled by BMAL1 intrinsic to keratinocytes as keratinocyte-specific deletion of Bmal1 obliterates time of day dependent synchronicity of cell division in the epidermis leading to a constitutively elevated cell proliferation. Consistent with higher cellular susceptibility to UV-induced DNA damage during S phase, we found that mice are most sensitive to UVB-induced DNA damage in the epidermis at night. As maximum numbers of keratinocytes go through S phase in the late afternoon in the human epidermis, we speculate that in humans the circadian clock imposes regulation of epidermal cell proliferation such that skin is at a particularly vulnerable stage during times of maximum UV exposure, thus contributing to the high incidence of human skin cancers. Whole skin was collected at 4 hour intervals for 48 hours. ZT number indicates the number of hours elapsed from when lights are switched on. ZT0 = lights on (6am). ZT12=lights off (6pm). Total RNA was purified from the skin of each mouse and equal amount of RNA from the 3 replicates for each time point were pooled. Anagen samples were collected from skin of P30 male mice.