UV Damage Research Articles

UV damage induces production of mitochondrial DNA fragments with specific length profiles.

UV light is a potent mutagen that induces bulky DNA damage in the form of cyclobutane pyrimidine dimers (CPDs). Photodamage and other bulky lesions occurring in nuclear genomes can be repaired through nucleotide excision repair (NER), where incisions on both sides of a damaged site precede the removal of a single-stranded oligonucleotide containing the damage. Mitochondrial genomes (mtDNAs) are also susceptible to damage from UV light, but current evidence suggests that the only way to eliminate bulky mtDNA damage is through mtDNA degradation. Damage-containing oligonucleotides excised during NER can be captured with antidamage antibodies and sequenced (XR-seq) to produce high-resolution maps of active repair locations following UV exposure. We analyzed previously published datasets from Arabidopsis thaliana, Saccharomyces cerevisiae, and Drosophila melanogaster to identify reads originating from the mtDNA (and plastid genome in A. thaliana). In A. thaliana and S. cerevisiae, the mtDNA-mapping reads have unique length distributions compared to the nuclear-mapping reads. The dominant fragment size was 26 nt in S. cerevisiae and 28 nt in A. thaliana with distinct secondary peaks occurring in regular intervals. These reads also show a nonrandom distribution of di-pyrimidines (the substrate for CPD formation) with TT enrichment at positions 7-8 of the reads. Therefore, UV damage to mtDNA appears to result in production of DNA fragments of characteristic lengths and positions relative to the damaged location. The mechanisms producing these fragments are unclear, but we hypothesize that they result from a previously uncharacterized DNA degradation pathway or repair mechanism in mitochondria.

Kinetics of inactivation of bacteria responsible for infections in hospitals using UV-LED

Controlling the microbial load in the environment is crucial to prevent the spread of organisms. The continuous spread of nosocomial infections in hospital facilities and the emergence of the coronavirus (COVID-19) highlighted the importance of disinfection processes in health safety. This work aimed to evaluate the effectiveness of LED-based disinfection lamps on bacteria from the ESKAPEE group and virus phage in vitro inactivation to be applied in hospital environments and health facilities disinfection.This study evaluated the effect of different UV wavelengths (275 nm, 280 nm (UVC), 310 nm (UVB) and 340 nm (UVA)) on the disinfection process of various microbial indicators including E. coli, S. aureus, P. aeruginosa, B. subtilis and Bacteriophage lambda DSM 4499. Exposure time (5 min–30 min), exposure distance (0.25 m and 0.5 m) and surface materials (glass, steel, and polished wood) were evaluated on the disinfection efficiency. Furthermore, the study determined the recovery capacity of each species after UV damage.UVC-LED lamps could inactivate 99.99 % of microbial indicators after 20 min exposures at a 0.5 m distance. The exposure time needed to completely inactivate E. coli, S. aureus, P. aeruginosa, B. subtilis and Bacteriophage lambda DSM 4499 can be decreased by reducing the exposure distance. UVB-LED and UVA-LED lamps were not able to promote a log reduction of 4 and were not effective on B. subtilis or bacteriophage lambda DSM 4499 inactivation. Thus, only UVC-LED lamps were tested on the decontamination of different surface materials, which was successful. P. aeruginosa showed the ability to recover from UV damage, but its inactivation rate remains 99.99 %, and spores from B. subtilis were not completely inactivated. Nevertheless, the inactivation rate of these indicators remained at 99.99 % with 24 h incubation after UVC irradiation. UVC-LED lamps emitting 280 nm were the most indicated to disinfect surfaces from microorganisms usually found in hospital environments.

Single-mitosis dissection of acute and chronic DNA mutagenesis and repair.

How chronic mutational processes and punctuated bursts of DNA damage drive evolution of the cancer genome is poorly understood. Here, we demonstrate a strategy to disentangle and quantify distinct mechanisms underlying genome evolution in single cells, during single mitoses and at single-strand resolution. To distinguish between chronic (reactive oxygen species (ROS)) and acute (ultraviolet light (UV)) mutagenesis, we microfluidically separate pairs of sister cells from the first mitosis following burst UV damage. Strikingly, UV mutations manifest as sister-specific events, revealing mirror-image mutation phasing genome-wide. In contrast, ROS mutagenesis in transcribed regions is reduced strand agnostically. Successive rounds of genome replication over persisting UV damage drives multiallelic variation at CC dinucleotides. Finally, we show that mutation phasing can be resolved to single strands across the entire genome of liver tumors from F1 mice. This strategy can be broadly used to distinguish the contributions of overlapping cancer relevant mutational processes.

A protocol for annotation of total body photography for machine learning to analyze skin phenotype and lesion classification.

Artificial Intelligence (AI) has proven effective in classifying skin cancers using dermoscopy images. In experimental settings, algorithms have outperformed expert dermatologists in classifying melanoma and keratinocyte cancers. However, clinical application is limited when algorithms are presented with 'untrained' or out-of-distribution lesion categories, often misclassifying benign lesions as malignant, or misclassifying malignant lesions as benign. Another limitation often raised is the lack of clinical context (e.g., medical history) used as input for the AI decision process. The increasing use of Total Body Photography (TBP) in clinical examinations presents new opportunities for AI to perform holistic analysis of the whole patient, rather than a single lesion. Currently there is a lack of existing literature or standards for image annotation of TBP, or on preserving patient privacy during the machine learning process. This protocol describes the methods for the acquisition of patient data, including TBP, medical history, and genetic risk factors, to create a comprehensive dataset for machine learning. 500 patients of various risk profiles will be recruited from two clinical sites (Australia and Spain), to undergo temporal total body imaging, complete surveys on sun behaviors and medical history, and provide a DNA sample. This patient-level metadata is applied to image datasets using DICOM labels. Anonymization and masking methods are applied to preserve patient privacy. A two-step annotation process is followed to label skin images for lesion detection and classification using deep learning models. Skin phenotype characteristics are extracted from images, including innate and facultative skin color, nevi distribution, and UV damage. Several algorithms will be developed relating to skin lesion detection, segmentation and classification, 3D mapping, change detection, and risk profiling. Simultaneously, explainable AI (XAI) methods will be incorporated to foster clinician and patient trust. Additionally, a publicly released dataset of anonymized annotated TBP images will be released for an international challenge to advance the development of new algorithms using this type of data. The anticipated results from this protocol are validated AI-based tools to provide holistic risk assessment for individual lesions, and risk stratification of patients to assist clinicians in monitoring for skin cancer.

Investigation into the effect of waste engine oil and vegetable oil recycling agents on the performance of laboratory-aged bitumen

The pavement recycling method is one of the practical ways to integrate sustainable development into transportation infrastructure, and it has been adopted worldwide. The use of reclaimed asphalt pavement (RAP) in new asphalt highways is limited due to the ageing effects caused by UV damage and weathering on the asphalt binder. To address this issue, waste vegetable oil (WVO) and waste engine oil (WEO) have been proposed as potential rejuvenating agents to enhance the recyclability of pavements containing RAP. This study evaluated the effectiveness of WEO and WVO as chemical rejuvenating agents through various tests on both aged and virgin asphalt binders. The tests included measurements of ductility, fire, and flash points, softening points, and penetration. The results indicate that the addition of WEO and WVO can improve the low-temperature properties of asphalt binders when mixed with RAP, resulting in reduced stiffness. The mixture containing WEO and WVO exhibited improved stability compared to the control, suggesting enhanced flow with increasing waste oil content in comparison to aged binder, albeit with slightly reduced flow compared to the virgin binder. This study demonstrates the potential of WEO and WVO as recycling agents to enhance the performance of bituminous mixes incorporating RAP.

Abstract 3042: Unraveling the mechanism of YAP toxicity in neuroendocrine solid tumors: Insights from Merkel cell carcinoma

Abstract The Hippo pathway, a pivotal regulator orchestrating organ size and tissue growth, has emerged as a central player in cancer biology. The downstream transcription factor YAP within this pathway has been implicated in diverse oncogenic processes. YAP activation contributes to drug resistance, metastasis, and poor clinical outcomes in many solid tumors. Conversely, YAP exhibits growth-suppressive effects in neuroendocrine (NE) solid cancers, a paradox that remains poorly understood. Analysis of RNAseq data from the Cancer Cell Line Encyclopedia (CCLE) revealed a distinct classification of tumors into YAP1-expressing (YAPon) and non-expressing (YAPoff) subgroups, with hematopoietic malignancies and NE solid tumors featured prominently in the latter. Merkel cell carcinoma (MCC) is a rare, high-grade, NE carcinoma of the skin with two distinct etiologies. Virus-positive MCC contains integrated Merkel cell polyomavirus that expresses the viral T antigens and virus-negative MCC caused by sunlight exposure and extensive UV damage. Bulk RNAseq performed with more than 60 MCC tumors revealed that YAP expression displayed an inverse correlation with an NE gene expression signature. To gain insight into why YAP expression is so low in MCC, we generated MCC cell lines with inducible expression of YAP. Expression of YAP led to growth arrest and cell death. We performed a genome-wide CRISPR-Cas9 screen to identify genes that when lost enable MCC cells to tolerate YAP expression. Functional enrichment analysis of the positively selected genes uncovered a variety of signaling pathways. Intriguingly, the CRISPR screen revealed a positive enrichment of non-canonical BAF complex members, including BRD9 and SMARCD1. To validate this finding, we treated MKL-1 cells with a BRD9 inhibitor, observing a substantial reduction in YAP toxicity. These findings open avenues for the development of targeted therapeutic strategies for high grade NE cancers, addressing a critical gap in our understanding of YAP biology in the context of MCC and beyond. Citation Format: Furkan Bahar, Thomas C. Frost, Varsha Ananthapadmanabhan, Julia L. Schnabel, Manisha Thakuria, James A. DeCaprio. Unraveling the mechanism of YAP toxicity in neuroendocrine solid tumors: Insights from Merkel cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3042.

A study on the anti-senescent effects of flavones derived from Prinsepia utilis Royle seed residue

Ethnopharmacological relevancePrinsepia utilis Royle, also known as the Anas fruit, is a unique perennial woody oil plant from Yunnan Province, China. In the ancient texts of Dongba sutras and Yunnan Southern Materia Medica, it has been documented that the local Naxi, Tibetan, and Mosuo communities extensively utilize the root and leaf fruits of green thorns for various purposes. These include treating mild-to-moderate specific dermatitis, moisturising the skin, providing protection against UV damage, aiding childbirth in pregnant women, safeguarding stomach health, reducing the risk of arteriosclerosis, and delaying aging. Aim of the studyIn this study, leftover residues from oil extraction were efficiently reused, and flavonoids were identified during subsequent extraction and separation processes. The anti-senescent effects of flavonoids in P. utilis Royle have not been systematically studied. Therefore, the objective of this study was to explore the anti-senescent properties of the flavonoids obtained from P. utilis Royle. MethodsFirst, HPLC and other analytical techniques were used to identify the components of the P. utilis Royle flavonoid (PURF). Next, DPPH, hydroxyl radicals, superoxide anion O2−, collagenase, and elastase were initially detected using in vitro biochemical assays. To examine its antioxidant properties, a zebrafish model was used, and to confirm its anti-senescent effects, a d-galactose-induced mouse aging model was employed. The anti-senescent mechanism of PURF was examined using a natural senescence HFF model. Furthermore, the anti-senescent target was confirmed using a 3D full T-Skin™ model. ResultsIn vitro biochemical assays demonstrated that flavones exhibited potent antioxidant activity and anti-senescent potential by inhibiting DPPH, hydroxyl radicals, superoxide anion O2−, collagenase, and elastase. It significantly enhanced the antioxidant effect on zebrafish while suppressing ROS and inflammatory injury, up-regulating COL1A1, COL3A1, AMPK, and mTOR gene expression and down-regulating MMP-9, TGF-β, p21, and p16 gene expression suggesting its potential anti-senescent ability. Findings from the D-galactose-induced aging mouse model showed that PURF greatly increased SOD levels, while simultaneously decreasing HYP and MDA levels. In addition, when PURF was given to the HFF cell and 3D full T-Skin™ model, consistent trends were observed in gene and protein expression, with up-regulation of COL1A1, COL3A1, AMPK, and mTOR genes and down-regulation of TGF-β, MMP-1, MMP-9, p21, and p16 genes. Therefore, these preliminary findings indicate that flavones can modulate AMPK/mTOR/TGF-β signalling pathways to exert its influence. ConclusionThe kernel residue of natural P. utilis Royle oil extracted from Yunnan province was previously considered agricultural waste, but we successfully extracted and isolated its flavonoid components. Our preliminary studies demonstrated its potential as an environmentally friendly anti-senescent raw material.

Acute exposure to ultraviolet radiation targets proteins involved in collagen fibrillogenesis.

Introduction: Exposure to chronic, low-dose UV irradiation (UVR) can lead to premature ageing of the skin. Understanding which proteins are affected by acute UVR and photo-dynamically produced reactive oxygen species (ROS) could help to inform strategies to delay photoageing. Conventional biochemical analyses can be used to characterize UVR/ROS-induced damage on a protein-by-protein basis and we have previously shown using SDS-PAGE that collagen I and plasma fibronectin are respectively resistant and susceptible to physiological doses of UVR. The aim of this study was to screen a complex proteome for UVR-affected proteins. Methods: This study employed a sensitive mass spectrometry technique (peptide location fingerprinting: PLF) which can identify structure associated differences following trypsin digestion to characterize the impact of UVR exposure on purified collagen I and tissue fibronectin and to identify UVR-susceptible proteins in an ECM-enriched proteome. Results: Using LC/MS-MS and PLF we show that purified mature type-I collagen is resistant to UVR, whereas purified tissue fibronectin is susceptible. UV irradiation of a human dermal fibroblast-deposited ECM-enriched proteome in vitro, followed by LC/MS-MS and PLF analysis revealed two protein cluster groups of UV susceptible proteins involved in i) matrix collagen fibril assembly and ii) protein translation and motor activity. Furthermore, PLF highlighted UV susceptible domains within targeted matrix proteins, suggesting that UV damage of matrix proteins is localized. Discussion: Here we show that PLF can be used to identify protein targets of UVR and that collagen accessory proteins may be key targets in UVR exposed tissues.

The metabolism of melanin synthesis-From melanocytes to melanoma.

Melanin synthesis involves the successful coordination of metabolic pathways across multiple intracellular compartments including the melanosome, mitochondria, ER/Golgi, and cytoplasm. While pigment production offers a communal protection from UV damage, the process also requires anabolic and redox demands that must be carefully managed by melanocytes. In this report we provide an updated review on melanin metabolism, including recent data leveraging new techniques, and technologies in the field of metabolism. We also discuss the many aspects of melanin synthesis that intersect with metabolic pathways known to impact melanoma phenotypes and behavior. By reviewing the metabolism of melanin synthesis, we hope to highlight outstanding questions and opportunities for future research that could improve patient outcomes in pigmentary and oncologic disease settings.

Structure-specific DNA endonuclease T7 endonuclease I cleaves DNA containing UV-induced DNA lesions.

The T7 gene 3 product, T7 endonuclease I, acts on various substrates with DNA structures, including Holliday junctions, heteroduplex DNAs and single-mismatch DNAs. Genetic analyses have suggested the occurrence of DNA recombination, replication and repair in Escherichia coli. In this study, T7 endonuclease I digested UV-irradiated covalently closed circular plasmid DNA into linear and nicked plasmid DNA, suggesting that the enzyme generates single- and double-strand breaks (SSB and DSB). To further investigate the biochemical functions of T7 endonuclease I, we have analysed endonuclease activity in UV-induced DNA substrates containing a single lesion, cyclobutane pyrimidine dimers (CPD) and 6-4 photoproducts (6-4PP). Interestingly, the leading cleavage site for CPD by T7 endonuclease I is at the second and fifth phosphodiester bonds that are 5' to the lesion of CPD on the lesion strand. However, in the case of 6-4PP, the cleavage pattern on the lesion strand resembled that of CPD, and T7 endonuclease I could also cleave the second phosphodiester bond that is 5' to the adenine-adenine residues opposite the lesion, indicating that the enzyme produces DSB in DNA containing 6-4PP. These findings suggest that T7endonuclease I accomplished successful UV damage repair by SSB in CPD and DSB in 6-4PP.

Quantitative probability estimation of light-induced inactivation of SARS-CoV-2

During the COVID pandemic caused by the SARS-CoV-2 virus, studies have shown the efficiency of deactivating this virus via ultraviolet light. The damage mechanism is well understood: UV light disturbs the integrity of the RNA chain at those locations where specific nucleotide neighbors occur. In this contribution, we present a model to address certain gaps in the description of the interaction between UV photons and the RNA sequence for virus inactivation. We begin by exploiting the available information on the pathogen’s morphology, physical, and genomic characteristics, enabling us to estimate the average number of UV photons required to photochemically damage the virus’s RNA. To generalize our results, we have numerically generated random RNA sequences and checked that the distribution of pairs of nucleotides susceptible of damage for the SARS-CoV-2 is within the expected values for a random-generated RNA chain. After determining the average number of photons reaching the RNA for a preset level of fluence (or photon density), we applied the binomial probability distribution to evaluate the damage of nucleotide pairs in the RNA chain due to UV radiation. Our results describe this interaction in terms of the probability of damaging a single pair of nucleotides, and the number of available photons. The cumulative probability exhibits a steep sigmoidal shape, implying that a relatively small change in the number of affected pairs may trigger the inactivation of the virus. Our light-RNA interaction model quantitatively describes how the fraction of affected pairs of nucleotides in the RNA sequence depends on the probability of damaging a single pair and the number of photons impinging on it. A better understanding of the underlying inactivation mechanism would help in the design of optimum experiments and UV sanitization methods. Although this paper focuses on SARS-CoV-2, these results can be adapted for any other type of pathogen susceptible of UV damage.

High photoreactivation activities of Rad2 and Rad14 in recovering insecticidal Beauveria bassiana from solar UV damage

Anti-ultraviolet (UV) roles of Rad2 and Rad14 depend on nucleotide excision repair (NER) of UV-induced DNA lesions in budding yeast but remain unexplored yet in filamentous fungi. Here, nucleus-specific Rad2 and Rad14 orthologs are shown to recover Beauveria bassiana, a main source of wide-spectrum mycoinsecticides, from solar UV damage through photorepair-depending photoreactivation. As a photorepair index, photoreactivation (germination) rates of lethal UVB dose-irradiated conidia via a 3- or 5-h light plus 9- or 7-h dark incubation at 25 °C were drastically reduced in the Δrad2 and Δrad14 mutants versus a wild-type strain. As an NER index, nighttime-mimicking 12-h dark reactivation rates of low UVB dose-impaired conidia decreased sharply compared to the corresponding photoreactivation rates in the presence or absence of either ortholog, indicating that its extant NER activity was limited to recovering light UVB damage in the field. The high photoreactivation activity of either Rad2 or Rad14 was derived from its tight link to a large protein complex formed by photolyase regulators and other anti-UV proteins through multiple protein-protein interactions revealed by yeast two-hybrid assays. Therefore, Rad2 and Rad14 recover B. bassiana from solar UV damage through photoreactiovation in vivo that depends primarily on photorepair, although they contribute little to the fungal lifecycle-related phenotypes. These findings unveil a novel scenario distinguished from the NER-depending anti-UV roles of Rad2 and Rad14 in the model yeast and broaden a biological basis crucial for rational application of fungal insecticides to improve pest control efficacy via feasible recovery of solar UV damage.

Nutlin-3 Loaded Ethosomes and Transethosomes to Prevent UV-Associated Skin Damage.

The skin's protective mechanisms, in some cases, are not able to counteract the destructive effects induced by UV radiations, resulting in dermatological diseases, as well as skin aging. Nutlin-3, a potent drug with antiproliferative activity in keratinocytes, can block UV-induced apoptosis by activation of p53. In the present investigation, ethosomes and transethosomes were designed as delivery systems for nutlin-3, with the aim to protect the skin against UV damage. Vesicle size distribution was evaluated by photon correlation spectroscopy and morphology was investigated by cryogenic transmission electron microscopy, while nutlin-3 entrapment capacity was evaluated by ultrafiltration and HPLC. The in vitro diffusion kinetic of nutlin-3 from ethosomes and transethosomes was studied by Franz cell. Moreover, the efficiency of ethosomes and transethosomes in delivering nutlin-3 and its protective role were evaluated in ex vivo skin explants exposed to UV radiations. The results indicate that ethosomes and transethosomes efficaciously entrapped nutlin-3 (0.3% w/w). The ethosome vesicles were spherical and oligolamellar, with a 224 nm mean diameter, while in transethosome the presence of polysorbate 80 resulted in unilamellar vesicles with a 146 nm mean diameter. The fastest nutlin-3 kinetic was detected in the case of transethosomes, with permeability coefficients 7.4-fold higher, with respect to ethosomes and diffusion values 250-fold higher, with respect to the drug in solution. Ex vivo data suggest a better efficacy of transethosomes to promote nutlin-3 delivery within the skin, with respect to ethosomes. Indeed, nutlin-3 loaded transethosomes could prevent UV effect on cutaneous metalloproteinase activation and cell proliferative response.

Rad6, a ubiquitin conjugator required for insect-pathogenic lifestyle, UV damage repair, and genomic expression of Beauveria bassiana

The E2 ubiquitin conjugator Rad6 is required for DNA damage bypass in budding yeast but remain functionally unknown in filamentous fungi. Here, we report pleiotropic effect of Rad6 ortholog in Beauveria bassiana, a wide-spectrum fungal insecticide. Global ubiquitination signal was greatly attenuated in the absence of rad6. The blocked ubiquitination led to severe growth defect, blocked asexual development, and abolished infectivity/insect pathogenicity, which correlated with compromised conidial quality (including viability, hydrophobicity, adherence to insect cuticle, and thermotolerance) and blocked secretion of cuticle-degrading enzymes including Pr1 family proteases. Importantly, Rad6 played much greater role in photoreactivation of UVB-impaired conidia by a 3- or 5-h light plus 9- or 7-h dark incubation than in dark reactivation of those impaired conidia by a 12-h dark incubation. The high activity of Rad6 in photoreactivation in vivo was derived from its link to a protein complex cored by the photolyase regulators WC1 and WC2 via the strong interactions of Rad6 with the E3 partner Rad18 and Rad18 with WC2 revealed in yeast two-hybrid assays. Transcriptomic analysis resulted in identification of 2700 differentially regulated genes involved in various function categories and metabolism pathways, indicating a regulatory role of Rad6-mediated ubiquitination in gene expression networks and genomic stability. Conclusively, Rad6 is required for asexual and insect-pathogenic lifecycles, solar UV damage repair, and genomic expression of B. bassiana. The primary dependence of its strong anti-UV role on photoreactivation in vivo unveils a scenario distinct from the core role of its yeast ortholog in DNA damage bypass.

Single and hybrid effects of nano‐TiO2 and ‐ZnO particles on multifunctional properties of textiles

AbstractImpregnation of nano‐metal oxides can provide functional properties to textiles, like UV protection and self‐cleaning properties. These properties are quite important as they can provide protection against UV damage, help to reduce cleaning efforts, improve the ease of maintenance, and help to protect the water resources. The usage of nanoparticles improves multifunctional effects due to their high surface area. Therefore, in this study, nano‐sized TiO2 and ZnO were applied to cotton fabrics as single type or hybrids with different concentrations to reveal their effects on multifunctional properties (UV‐protection, self‐cleaning, wettability, photocatalytic activity). Also, the weight and air permeability of samples were determined to evaluate their usability. Scanning electron microscopy, x‐ray diffraction and Fourier transform infrared spectroscopy were also utilized to analyze the samples. According to the results, some samples exhibited good–very good UV protection. Up to 78.5% photocatalytic degradation of organic dye was achieved by nano‐TiO2 application. According to self‐cleaning test results, nano‐TiO2 applied samples showed yellowing after UV irradiation. Hybrid‐coated samples were more advantageous regarding self‐cleaning, especially against cherry juice stains. The staining and wettability results of the samples were in accordance. Weight and air permeability changes were acceptable to maintain the usage of the samples for clothing and other applications.

FTO-mediated regulation of m6A methylation is closely related to apoptosis induced by repeated UV irradiation

BackgroundUltraviolet (UV) damage is closely related to skin photoaging and many skin diseases, including dermatic tumors. N6-methyladenosine (m6A) modification is an important epigenetic regulatory mechanism. However, the role of m6A methylation in apoptosis induced by repeated UV irradiation has not been characterized. ObjectiveTo explore m6A methylation changes and regulatory mechanisms in the repeated UV-induced skin damage process, especially apoptosis. MethodsHaCaT cells and BALB/c-Nu nude mice were exposed to repeated UVB/UVA+UVB irradiation. Colorimetry and flow cytometry were used to measure cellular viability and apoptosis. m6A-modified genes were detected via colorimetry and methylated RNA immunoprecipitation (MeRIP) sequencing. Methyltransferases and demethylases were detected via RT-PCR, western blotting and immunohistochemistry. Transfection of siRNA and plasmid was performed to knock down or overexpress the selected genes. ResultsAfter UVB irradiation, 861 m6A peaks were increased and 425 m6A peaks were decreased in HaCaT cells. The differentially modified genes were enriched in apoptosis-related pathways. The m6A demethylase FTO was decreased in both HaCaT cells and mouse skin after UV damage. Overexpressing FTO could improve cell viability, inhibit apoptosis and decrease RNA-m6A methylation, including LPCAT3-m6A, which increase LPCAT3 expression, cell viability promotion and apoptosis inhibition. ConclusionOur study identified the cell m6A methylation change lists after repeated UVB irradiation, and revealed that FTO and LPCAT3 play key roles in the m6A methylation pathogenesis of UV-induced skin cell apoptosis. FTO-m6A-LPCAT3 might serve as a novel upstream target for preventing and treating photoaging and UV-induced skin diseases.

The Role of hBRCA2 in the Repair of Spontaneous and UV DNA Damage in Saccharomyces cerevisiae.

Women with mutations in the human BRCA2 gene ( hBRCA2 ) have an increased risk of developing breast and ovarian cancer throughout their lifetime. hBRCA2 transcribes proteins necessary for gene repair through homologous recombination (HR). In order to better understand the role of hBRCA2 in response to specific types of DNA damage, the present study evaluated HR in the budding yeast, Saccharomyces cerevisiae , using wildtype (WT) and rad52Δ mutant cells subject to spontaneous and UV damage in the presence or absence of hBRCA2. As expected, rad52Δ genotypes yielded lower recombination frequencies compared to WT in both spontaneous and UV exposure experiments. However, there was no significant difference between rad52Δ mutants with or without hBRCA2. Interestingly, higher UV exposure resulted in a relative increase in HR for only the rad52Δ mutant genotypes. The results demonstrate that hBRCA2 complementation may not be as substantial in spontaneous or UV DNA damage compared to double-strand break DNA damage, as previous work has shown.

Vitamin C compounds mixture prevents skin barrier alterations and inflammatory responses upon real life multi pollutant exposure.

Cutaneous tissues is among the main target of outdoor stressors such as ozone (O3 ), particulate matter (PM), and ultraviolet radiation (UV) all involved in inducing extrinsic skin aging. Only a few reports have studied the multipollutant interaction and its effect on skin damage. In the present work, we intended to evaluate the ability of pollutants such as O3 and PM to further aggravate cutaneous UV damage. In addition, the preventive properties of a cosmeceutical formulation mixture (AOX mix) containing 15% vitamin C (L-ascorbic acid), 1% vitamin E (α-tocopherol) and 0.5% ferulic acid was also investigated. Skin explants obtained from three different subjects were exposed to 200 mJ UV light, 0.25 ppm O3 for 2 h, and 30 min of diesel engine exhaust (DEE), alone or in combination for 4 days (time point D1 and D4). The results showed a clear additive effect of O3 and DEE in combination with UV in terms of keratin 10, Desmocollin and Claudin loss. In addition, the multipollutant exposure significantly induced the inflammatory response measured as NLRP1/ASC co-localization suggesting the activation of the inflammasome machinery. Finally, the loss of Aquaporin3 was also affected by the combined outdoor stressors. Furthermore, daily topical pre-treatment with the AOX Mix significantly prevented the cutaneous changes induced by the multipollutants. In conclusion, this study is among the first to investigate the combined effects of three of the most harmful outdoor stressors on human skin and confirms that daily topical of an antioxidant application may prevent pollution-induced skin damage.

Herbal skincare paste: Formulation and demonstration its therapeutic potential for dermatological applications

The increasing prevalence of tanning as a skincare concern, due to factors such as pollution, stress, UV radiation, and lifestyle, has prompted the need for the development of organic anti-tan formulations. The current study aims to synthesize an organic anti-tan substance and evaluate its various properties for both stability and effectiveness. It is well-known that the skin's natural defense mechanism against UV damage is the development of melanin, a dark brown pigment, to protect the skin from burning. Historically, plants have been utilized to meet the basic requirements for healthy and beautiful skin. However, conventional cosmetics often contain toxic ingredients that can lead to regenerative issues and increased growth hazards, with studies suggesting that the more products utilized, the higher the potential for harmful concentrations in the body. Therefore, it is recommended to avoid cosmetics altogether. However, if use is deemed necessary, the use of natural or organic cosmetics is suggested. This project aims to create and assess a polyherbal face and body pack for cosmetic use, utilizing only natural ingredients.

Thallium(I) induces a prolonged inhibition of (6-4)photoproduct binding and UV damage excision repair activities in zebrafish (Danio rerio) embryos via protein inactivation

Cyclobutane pyrimidine dimer (CPD) and (6-4)photoproduct (6-4 PP) are two major types of UV-induced DNA lesion and 6-4 PP is more mutagenic than CPD. Activated by lesion detection, nucleotide excision repair (NER) eliminates CPDs and 6-4 PPs. Thallium (Tl) is a toxic metal existing primarily as Tl+ in the aquatic environment. Ingestion of Tl+-contaminated foods and water is a major route of human poisoning. As Tl+ may inhibit enzyme activities via binding to sulfhydryl groups, this study explored if Tl+ could intensify UV mutagenicity by inactivating NER-linked damage recognition factors using zebrafish (Danio rerio) embryo as a model system. Incubation of Tl+ (as thallium nitrate) at 0.1–0.4 μg/mL with zebrafish extracts for 20 min caused a concentration-dependent inhibition of 6-4 PP binding activities as shown by a photolesion-specific band shift assay, while CPD binding activities were insensitive to Tl+. The ability of Tl+ to suppress 6-4 PP detection was stronger than that of Hg2+. Exposure of zebrafish embryos at 1 h post fertilization (hpf) to Tl+ at 0.4–1 μg/mL for 9 or 71 h also specifically inhibited 6-4 PP detection, indicating that Tl+ induced a prolonged inhibition of 6-4 PP sensing ability primarily via its direct interaction with damage recognition molecules. Tl+-mediated inhibition of 6-4 PP binding in embryos at distinct stages resulted in a suppression of NER capacity monitored by a transcription-based DNA repair assay. Our results revealed the potential of Tl+ to enhance UV mutagenicity by disturbing the removal of 6-4 PP through repressing the lesion detection step of NER.