Project description:Solar urticaria (SU) is clinically characterised by rapid onset sunlight-induced urticaria, but its cutaneous pathophysiology is not well understood. The aim of this study was to investigate cutaneous cellular and molecular events in the evolution of SU responses following solar simulated ultraviolet radiation (SSR) exposure, and compare with responses in healthy controls (HC). Cutaneous biopsies were taken from unexposed skin and from skin exposed to a single low (physiological) dose of SSR, at 30 minutes, 3 hours and 24 hours post-exposure, in n=6 SU patients and n=6 HC. Biopsies were assessed by immunohistochemistry (n=6 SU, n=6 HC) and RNA-sequencing analysis (n=4 SU, n=4 HC). This dataset contains RNAseq data from the SU patients.
Project description:Long-term exposure of human skin to ultraviolet radiation (UVR) in sunlight negatively impacts its appearance and function with photoaged skin having a characteristic leathery, rough appearance, with deep wrinkles. These clinical features of photodamage are thought to result from UVR-induced remodelling of the dermal extracellular matrix, particularly the elastic fibre system. There are few in vivo human data on the impact of acute UVR exposure on this fibre system and particularly solar-simulated radiation (SSR)-mediated effects. We examined the differential effect of broadband UVB and SSR on the human dermal elastic fibre system, and specifically the microfibrillar components fibrillin-1, fibulin-2 and fibulin-5. Healthy white Caucasian adults (skin type II-III) were recruited and irradiated with 3× their minimal erythema dose of broadband UVB (n = 6) or SSR (n = 6) on photoprotected buttock skin. Punch biopsies were taken 24 h after irradiation and from unirradiated control skin. Overall, histological assessment of elastic fibres revealed significantly less elastic fibre staining in broadband UVB (P = 0.004) or SSR (P = 0.04) irradiated skin compared to unirradiated control skin. Significantly less staining of fibrillin-1-positive microfibrils was also observed in the papillary dermis of UVB irradiated skin (P = 0.02) but not skin exposed to SSR. Conversely, immunohistochemistry for fibulin-5-positive microfibrils revealed significantly less expression in skin exposed to SSR (P = 0.04) but not to broadband UVB. There was no significant change in fibulin-2-positive microfibrils following either broadband UVB or SSR irradiation. Thus, broadband UVB and SSR mediate differential effects on individual components of the dermal elastic fibre network in human skin. Further human studies are required to explore the mechanisms underlying these findings and the impact of potential photoprotective agents.
Project description:Despite widespread use of sunscreens that minimize erythema by blocking ultraviolet B (UVB) radiation, incidence rates of melanoma continue to rise. In considering this disparity between intervention and disease prevalence, we investigated the in vivo transcriptome of human skin treated with sunscreen and solar-simulated radiation (ssR). A focal skin area of healthy participants was exposed to ssR at 1 minimal erythema dose (MED), 0.1 MED or 100 J/m2 with or without prior application of sunscreen, or to non-UVB-spectrum of ssR (solar-simulated UVA/visible/infrared radiation: ssA). Skin biopsies were analyzed using expression microarrays.
Project description:The aim of this study was to investigate cutaneous cellular and molecular events in the photodermatoses (including solar urticaria and photoaggravated atopic dermatitis) following solar simulated ultraviolet radiation (SSR) exposure, and this dataset comprised the healthy controls (HC). Cutaneous biopsies were taken from unexposed skin and from skin exposed to a single low (physiological) dose of SSR, at 30 minutes, 3 hours, 24 hours and 72 hours post-exposure, in n=6 HC. Biopsies were assessed by immunohistochemistry (n=6 HC) and RNA-sequencing analysis (n=4 HC).
Project description:Actinic keratoses (AKs) and squamous cell carcinoma in situ (SCCIS) are precursor lesions for cutaneous squamous cell carcinoma (cSCC), the second most common form of cancer. Current topical therapies for AKs and SCCIS promote skin inflammation to eradicate lesions and do not directly target the biological mechanisms driving growth. We hypothesized that topical small molecule inhibitors targeting kinases promoting keratinocyte growth in AKs and SCCIS could induce regression of these lesions with less inflammation. To test this hypothesis, we determined the efficacy of topical dasatinib, 5-fluorouracil and BEZ-235 in inducing regression of cSCCs in the K14-Fyn Y528 transgenic mouse model. Topical dasatinib induced regression of cSCC with less inflammation, no ulceration and no mortality compared to 5-fluorouracil. Topical BEZ-235 induced cSCC regression similar to dasatinib without erythema or ulceration. These data indicate that topical small molecule kinase inhibitors targeting drivers of AK/SCCIS/cSCC growth represent a promising therapeutic approach to treat these common skin lesions.
Project description:Despite widespread use of sunscreens that minimize erythema by blocking ultraviolet B (UVB) radiation, incidence rates of melanoma continue to rise. In considering this disparity between intervention and disease prevalence, we investigated the in vivo transcriptome of human skin treated with sunscreen and solar-simulated radiation (ssR). A focal skin area of healthy participants was exposed to ssR at 1 minimal erythema dose (MED), 0.1 MED or 100 J/m2 with or without prior application of sunscreen, or to non-UVB-spectrum of ssR (solar-simulated UVA/visible/infrared radiation: ssA). Skin biopsies were analyzed using expression microarrays. Ninety-eight microarrays from 14 healthy human volunteers were analyzed. Focal skin areas of all 14 volunteers were exposed to 0 J/m2, 100 J/m2, 1 minimal erythema dose (MED), and 0.1 MED of solar-simulated radiation (ssR). Eight of the 14 volunteers (Group 1) were also exposed to ssA (ssR minus UVB) that were generated by removing UVB from 0 J/m2, 100 J/m2, 1 minimal erythema dose (MED), and 0.1 MED of ssR. Additionally, 6 of the 14 volunteers (Group 2) were treated with sunscreen of sun protection factor (SPF) 15, and exposed to 0 J/m2, 100 J/m2, 1 minimal erythema dose (MED), and 0.1 MED of ssR. Biopsy was taken 24 hours after exposure from each focal skin area for RNA extraction.
Project description:The transcription factor Nrf2 determines the ability to adapt and survive under conditions of electrophilic, oxidative, and inflammatory stress by regulating the expression of elaborate networks comprising nearly 500 genes encoding proteins with versatile cytoprotective functions. In mice, disruption of Nrf2 increases susceptibility to carcinogens and accelerates disease pathogenesis. Paradoxically, Nrf2 is upregulated in established human tumors, but whether this upregulation drives carcinogenesis is not known. Here we show that the incidence, multiplicity, and burden of solar-simulated UV radiation-mediated cutaneous tumors that form in SKH-1 hairless mice in which Nrf2 is genetically constitutively activated are lower than those that arise in their wild-type counterparts. Pharmacologic Nrf2 activation by topical biweekly applications of small (40 nmol) quantities of the potent bis(cyano enone) inducer TBE-31 has a similar protective effect against solar-simulated UV radiation in animals receiving long-term treatment with the immunosuppressive agent azathioprine. Genetic or pharmacologic Nrf2 activation lowers the expression of the pro-inflammatory factors IL6 and IL1β, and COX2 after acute exposure of mice to UV radiation. In healthy human subjects, topical applications of extracts delivering the Nrf2 activator sulforaphane reduced the degree of solar-simulated UV radiation-induced skin erythema, a quantifiable surrogate endpoint for cutaneous damage and skin cancer risk. Collectively, these data show that Nrf2 is not a driver for tumorigenesis even upon exposure to a very potent and complete carcinogen and strongly suggest that the frequent activation of Nrf2 in established human tumors is a marker of metabolic adaptation.
Project description:Ultraviolet radiation (UVR) from sunlight is the major effector for skin aging and carcinogenesis. However, genes and pathways altered by solar-simulated UVR (ssUVR), a mixture of UVA and UVB, are not well characterized. Here we report global changes in gene expression as well as associated pathways and upstream transcription factors in human keratinocytes exposed to ssUVR. Human HaCaT keratinocytes were exposed to either a single dose or 5 repetitive doses of ssUVR. Comprehensive analyses of gene expression profiles as well as functional annotation were performed at 24 hours post irradiation. Our results revealed that ssUVR modulated genes with diverse cellular functions in a dose-dependent manner. Gene expression in cells exposed to a single dose of ssUVR differed significantly from those that underwent repetitive exposures. While single ssUVR caused a significant inhibition in genes involved in cell cycle progression, especially G2/M checkpoint and mitotic regulation, repetitive ssUVR lead to extensive changes in genes related to cell signaling and metabolism. We have also identified a panel of ssUVR target genes that exhibited persistent changes in gene expression even at 1 week after irradiation. These results revealed a complex network of transcriptional regulators and pathways that orchestrate the cellular response to ssUVR.
Project description:Solar ultraviolet radiation (UVR) is the most significant occupational carcinogenic exposure in terms of the number of workers exposed (i.e., outdoor workers). Consequently, solar UVR-induced skin cancers are among the most common forms of occupational malignancies that are potentially expected globally. This systematic review is registered in PROSPERO (CRD42021295221) and aims to assess the risk of cutaneous squamous cell carcinoma (cSCC) associated to occupational solar UVR exposure. Systematic searches will be performed in three electronic literature databases (PubMed/Medline, EMBASE, and Scopus). Further references will be retrieved by a manual search (e.g., in grey literature databases, internet search engines, and organizational websites). We will include cohort studies and case-control studies. Risk of Bias assessment will be conducted separately for case-control and cohort studies. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) will be used for the certainty of assessment. In case quantitative pooling is not feasible, a narrative synthesis of results will be performed.