UVB Irradiation Research Articles

Deficiency in Ever2 does not increase susceptibility of mice to pathogenesis by the mouse papillomavirus, MmuPV1.

Epidermodysplasia verruciformis (EV) is a rare genetic skin disorder that is characterized by the development of papillomavirus-induced skin lesions that can progress to squamous cell carcinoma (SCC). Certain high-risk, cutaneous β-genus human papillomaviruses (β-HPVs), in particular HPV5 and HPV8, are associated with inducing EV in individuals who have a homozygous mutation in one of three genes tied to this disease: EVER1, EVER2, or CIB1. EVER1 and EVER2 are also known as TMC6 and TMC8, respectively. Little is known about the biochemical activities of EVER gene products or their roles in facilitating EV in conjunction with β-HPV infection. To investigate the potential effect of EVER genes on papillomavirus infection, we pursued in vivo infection studies by infecting Ever2-null mice with mouse papillomavirus (MmuPV1). MmuPV1 shares characteristics with β-HPVs including similar genome organization, shared molecular activities of their early, E6 and E7, oncoproteins, the lack of a viral E5 gene, and the capacity to cause skin lesions that can progress to SCC. MmuPV1 infections were conducted both in the presence and absence of UVB irradiation, which is known to increase the risk of MmuPV1-induced pathogenesis. Infection with MmuPV1 induced skin lesions in both wild-type and Ever2-null mice with and without UVB. Many lesions in both genotypes progressed to malignancy, and the disease severity did not differ between Ever2-null and wild-type mice. However, somewhat surprisingly, lesion growth and viral transcription was decreased, and lesion regression was increased in Ever2-null mice compared with wild-type mice. These studies demonstrate that Ever2-null mice infected with MmuPV1 do not exhibit the same phenotype as human EV patients infected with β-HPVs.IMPORTANCEHumans with homozygous mutations in the EVER2 gene develop epidermodysplasia verruciformis (EV), a disease characterized by predisposition to persistent β-genus human papillomavirus (β-HPV) skin infections, which can progress to skin cancer. To investigate how EVER2 confers protection from papillomaviruses, we infected the skin of homozygous Ever2-null mice with mouse papillomavirus MmuPV1. Like in humans with EV, infected Ever2-null mice developed skin lesions that could progress to cancer. Unlike in humans with EV, lesions in these Ever2-null mice grew more slowly and regressed more frequently than in wild-type mice. MmuPV1 transcription was higher in wild-type mice than in Ever2-null mice, indicating that mouse EVER2 does not confer protection from papillomaviruses. These findings suggest that there are functional differences between MmuPV1 and β-HPVs and/or between mouse and human EVER2.

Seabuckthorn pulp extract alleviates UV-B-induced skin photo-damage by significantly reducing oxidative stress-mediated endoplasmic reticulum stress and DNA Damage in human primary skin fibroblasts and Balb/c mice skin.

Skin homeostasis is predominantly compromised by exposure to UV-B irradiation, leading to several physiopathological processes at cellular and tissue levels that deteriorate skin function and integrity. The current study investigated the photo-protective role of seabuckthorn fruit pulp (SBT) extract against UV-B-induced damage in primary human skin fibroblasts (HDFs) and Balb/C mice skin. We subjected HDFs and Balb/C mice to UV-B irradiation and measured multiple cellular damage indicators. We found that UV-B-irradiated HDFs treated with SBT had a considerably greater survival rate than cells exposed to UV-B radiation alone. The UV-B irradiation-induced ROS generation led to the degradation of the extracellular matrix, inflammation, DNA damage, endoplasmic reticulum (ER) stress, and apoptosis. SBT treatment significantly reduced these manifestations. Topical application of SBT alleviated UV-B-induced epidermal thickening, leukocyte infiltration, and degradation of extracellular matrix in Balb/c mice skin. Based on our results, we conclude that SBT has the potential to be developed as a therapeutic/cosmetic remedy for the prevention of skin photo-damage.

Evaluation test and analysis of a microneedle and iontophoresis based medical device "CELLADEEP Patch" in skin improvement on ex vivo human-derived skin tissue models.

Microneedles are tiny needles, typically ranging from tens to hundreds of micrometers in length, used in various medical procedures and treatments. The tested medical device named "CELLADEEP Patch" a dissolvable microneedle therapy system (MTS), made of hyaluronic acid and collagen. And the iontophoresis technique is also applied in the system. The study aimed to evaluate the effectiveness of the "CELLADEEP Patch" in skin improvement. Ex vivo human-derived skin tissue models were used in this study and they were divided into three different groups, namely, the Untreated Group, the Negative Control Group, and the Test Group respectively. The Untreated Group received no treatment measures, the Negative Control Group was exposed to ultraviolet B radiation (UVB) irradiation, and the Test Group was exposed to UVB irradiation and treated with "CELLADEEP Patch". Skin moisture content, transdermal water loss, and skin elasticity were evaluated by three clinical devices. Additionally, histological staining and related mRNA expression levels were also analyzed. The results of skin moisture content, transdermal water loss, and skin elasticity evaluation consistently illustrated that the application of "CELLADEEP Patch" led to remarkable skin improvement. And the analysis of histological staining images also confirmed the effectiveness of the "CELLADEEP Patch", especially for increasing collagen density. Moreover, the upregulation of Collagen type 1 a (COL1A1) and hyaluronan synthase 3 mRNA expression and the decrease of Matrix metalloproteinase 1 (MMP-1) and Interleukin-1 beta (IL-1β) mRNA expression reflected its wrinkle improvement, moisturizing and anti-inflammation function. "CELLADEPP Patch", the MTS combined with the iontophoresis technique, exhibits its effectiveness in moisturizing, skin elasticity improvement, and anti-inflammatory function when applied to ex vivo human-derived skin tissue models in experiments. The study has contributed to the understanding of the "CELLADEPP Patch" and laid the foundation for subsequent animal experiments and clinical trials.

Revealing the UV response of melanocytes in xeroderma pigmentosum group A using patient-derived induced pluripotent stem cells

BackgroundXeroderma pigmentosum (XP) is characterized by photosensitivity that causes pigmentary disorder and predisposition to skin cancers on sunlight-exposed areas due to DNA repair deficiency. Patients with XP group A (XP-A) develop freckle-like pigmented maculae and depigmented maculae within a year unless strict sun-protection is enforced. Although it is crucial to study pigment cells (melanocytes: MCs) as disease target cells, establishing MCs in primary cultures is challenging. ObjectiveElucidation of the disease pathogenesis by comparison between MCs differentiated from XP-A induced pluripotent stem cells (iPSCs) and healthy control iPSCs on the response to UV irradiation. MethodsiPSCs were established from a XP-A fibroblasts and differentiated into MCs. Differences in gene expression profiles between XP-A-iPSC-derived melanocytes (XP-A-iMCs) and Healthy control iPSC-derived MCs (HC-iMCs) were analyzed 4 and 12 h after irradiation with 30 or 150 J/m2 of UV-B using microarray analysis. ResultsXP-A-iMCs expressed SOX10, MITF, and TYR, and showed melanin synthesis. Further, XP-A-iMCs showed reduced DNA repair ability. Gene expression profile between XP-A-iMCs and HC-iMCs revealed that, numerous gene probes that were specifically upregulated or downregulated in XP-A-iMCs after 150-J/m2 of UV-B irradiation did not return to basal levels. Of note that apoptotic pathways were highly upregulated at 150 J/m2 UV exposure in XP-A-iMCs, and cytokine-related pathways were upregulated even at 30 J/m2 UV exposure. ConclusionWe revealed for the first time that cytokine-related pathways were upregulated even at low-dose UV exposure in XP-A-iMCs. Disease-specific iPSCs are useful to elucidate the disease pathogenesis and develop treatment strategies of XP.

Biodosimetry of UV radiation through the detection of cytogenetic endpoints in Allium cepa meristems

In this study, we examined the response of Allium cepa sprout stem cells, or meristems, to UVB and UVC radiation. The choice of Allium cepa, or onion, was made to avoid the controversial use of animal models. Allium cepa is a well-established in vivo standard model that is frequently used in cytogenetic research connected to various environmental contaminants. Indicators such as micronuclei and chromosomal abnormalities were used to evaluate the genotoxicity of UVB and UVC radiation, and the mitotic index was used to investigate the cytotoxicity of the radiation, providing information on cellular proliferation. The Shapiro-Wilk test (p < 0.05) confirmed the normality of the data. The analysis of the Pearson linear correlation coefficient (r = 0.97), conducted across all dose points considered, including the negative control, revealed an almost perfect positive linear relationship between the dose and the number of cells with micronuclei, for both UVB and UVC. The frequency of induction of micronuclei as a function of dose for both radiation types was found to be similar. However, a difference in the morphology of the cells exposed to UVB radiation compared to those exposed to UVC radiation was observed. In conclusion, the mitotic index analysis showed no significant differences in cell activity between UVC and UVB irradiation compared with control samples. The results from this study support the use of Allium cepa and cytogenetic endpoints as a biodosimetric method for ultraviolet radiation.

UVB-Aged Microplastics and Cellular Damage: An in Vitro Study

Plastics are synthetic organic compounds whose widespread use generates enormous waste. Different processes, such as mechanical abrasion, microbiological activity, and UVB irradiation, can fragment the plastic material and generate microplastics (MPs). MPs are ubiquitous, and various organisms, including humans, can ingest or inhale them, with potential adverse health effects. The differences between UV-aged and virgin particles were studied to evaluate the genotoxic damage and oxidative stress induced by polystyrene MPs with 1 and 5 µm sizes on the monocyte-like cell line (THP-1). Fourier transform infrared spectroscopy and Ζ-potential measurements were used to characterise MP particles after UVB exposure. Cells exposed to MPs show a widespread change in the cellular environment with the generation of reactive oxidative species (ROS), as indicated by the increased malondialdehyde level. The occurrence of genotoxic damage is correlated to the smaller size and ageing state of the MPs. The biochemical and genomic alterations observed in this in vitro study suggest that MPs, ubiquitous pollutants, following natural degradation and oxidation processes can cause various adverse effects on the health of the exposed population, making it necessary to carry out further studies to better define the real risk.

The protection role of human growth hormone on skin cells following ultraviolet B exposure

BackgroundUltraviolet-B (UVB) radiation is the leading environmental cause of skin damage and photoaging. The epidermis and dermis layers of the skin mainly absorb UVB. UVB stimulates apoptosis, cell cycle arrest, generation of reactive oxygen species, and degradation of collagen and elastin fibers. ObjectiveThis study investigated the potential of human growth hormone (hGH) in protecting the skin fibroblasts and keratinocytes (HFFF-2 and HaCaT cell lines) from UVB-induced damage. MethodsThe MTT assay was performed to evaluate UVB-induced mitochondrial damage via assessing the mitochondrial dehydrogenase activity, and flow cytometry was carried out to investigate the effects of UVB and hGH on the cell cycle and apoptosis of UVB-irradiated cells. In addition, the fold change mRNA expression levels of Type I collagen and elastin in HFFF-2 cells were evaluated using the qRT-PCR method following UVB exposure. ResultsWe observed that treatment of cells with hGH before UVB exposure inhibited UVB-induced loss of mitochondrial dehydrogenase activity, apoptosis, and sub-G1 population formation in both cell lines. We also found that hGH-treated HFFF-2 cells showed up-regulated mRNA expression of Type I collagen, elastin, and IGF-1 in response to UVB irradiation. ConclusionThese findings suggest hGH as a potential anti-UVB compound that can protect skin cells from UVB-induced damage. Our findings merit further investigation and can be used to better understand the role of hGH in skin photoaging.

EFFECT OF DIFFERENT UV EXPOSURE ENERGY ON POLYIMIDE-BASED NONVOLATILE RESISTIVE PHOTOMEMORY DEVICE

Recently, many researchers pay attractive attention to organic memory technology. Polyimide film was used as the resistive switching layer of nonvolatile photomemory in this study. In order to improve the performance of the device, different wavelengths of Ultraviolet (UV) light were used to operate the device, and its impact on the polyimide film was discussed. In this paper, three different UV light bands, UVA, UVB, and UVC, are used to switch devices between low resistance state (LRS) and high resistance state (HRS). It can be seen from the results that all three kinds of energies of UV light can transform the polyimide film from HRS to LRS successfully. According to the data, after 1s of UVB irradiation, the LRS current of polyimide-based photomemory device is the largest, and the data retention ability is also the best, the second is to irradiate UVA, and the last is to irradiate UVC. The results of the optical properties and electrical properties are coincidental. Therefore, different UV energies can affect this photomemory device.

UV-B irradiation enhances the accumulation of beneficial glucosinolates induced by melatonin in Chinese kale sprout

Cruciferous sprout is a new form of vegetable product rich in bioactive compounds, especially glucosinolates. Previous studies have focused on increasing the accumulation of glucosinolates in cruciferous sprouts by applying different chemical regulators, with a particular focus on their contribution to nutritional quality and health benefits. Nevertheless, the effects of melatonin and UV-B irradiation on glucosinolate biosynthesis remain unclear. In this study, it was found that changes in melatonin concentrations significantly affected the contents of individual as well as total aliphatic and indolic glucosinolates. The 5 μmol · L−1 melatonin was decided as the optimum concentration that could increase the content of beneficial glucosinolates including glucoraphanin and 4-methoxy glucobrassicin in Chinese kale sprouts. Notably, the enhancement of glucosinolate accumulation by melatonin treatment could be further amplified by UV-B irradiation. Furthermore, our results showed that R2R3-MYB transcription factor BoaMYB28 and BoaMYB51, which are central regulators of aliphatic and indolic glucosinolate biosynthesis respectively, were both involved in the regulation of glucosinolate biosynthesis by melatonin and UV-B irradiation. Additionally, the expression of glucosinolate biosynthetic genes, including BoaCYP79F1, BoaCYP83A1, BoaSUR1, BoaUGT74B1, BoaCYP79B2, BoaCYP79B3, and BoaCYP83B1 participated in the formation of core structures and BoaFMOGS-OX5, BoaAOP2, BoaCYP81F2, and BoaIGMT1 involved in the side-chain modification of aliphatic and indolic glucosinolate, was regulated by melatonin or UV-B irradiation. Taken together, these findings provide a potential strategy for improving the nutritional quality and resistance of Chinese kale sprouts.

UV-B Radiation Disrupts Membrane Lipid Organization and Suppresses Protein Mobility of GmNARK in Arabidopsis.

While it is well known that plants interpret UV-B as an environmental cue and a potential stressor influencing their growth and development, the specific effects of UV-B-induced oxidative stress on the dynamics of membrane lipids and proteins remain underexplored. Here, we demonstrate that UV-B exposure notably increases the formation of ordered lipid domains on the plasma membrane (PM) and significantly alters the behavior of the Glycine max nodule autoregulation receptor kinase (GmNARK) protein in Arabidopsis leaves. The GmNARK protein was located on the PM and accumulated as small particles in the cytoplasm. We found that UV-B irradiation interrupted the lateral diffusion of GmNARK proteins on the PM. Furthermore, UV-B light decreases the efficiency of surface molecule internalization by clathrin-mediated endocytosis (CME). In brief, UV-B irradiation increased the proportion of the ordered lipid phase and disrupted clathrin-dependent endocytosis; thus, the endocytic trafficking and lateral mobility of GmNARK protein on the plasma membrane are crucial for nodule formation tuning. Our results revealed a novel role of low-intensity UV-B stress in altering the organization of the plasma membrane and the dynamics of membrane-associated proteins.

Unveiling UVB resilience in Oryza sativa L.: Integrative analysis of physiological, molecular and microRNA responses

Rice is the staple food for more than half of the global population. It is cultivated in over 100 countries, and is predominant in Asia, which accounts for 90 % of the world's production. As the most crucial food crop globally, rice is sensitive to both UVB radiation and climate variations. UltraViolet-B radiation (UVB) is recognised as adverse factors for photosynthesis and plant growth. The current study investigates the resilience of Oryza sativa L. (IR20) seedlings to UVB irradiation, focusing on parameters such as photosynthetic pigment, total sugar, phenolic, total free amino acids, malondialdehyde content, hydrogen peroxide, and antioxidative enzymes. The mRNA expression levels of genes involved in UVB perception, signalling, and response (UVR8, HY5, RLCK, PHT2, and URP) were studied using quantitative RT-PCR (RT-qPCR). Additionally, a computational approach was employed to identify UVB-responsive microRNAs (miRNAs) and their corresponding target mRNAs; which were subsequently validated using stem-loop RT-qPCR and RT-qPCR, respectively. Surprisingly, it was discovered that the H2O2 content in the IR20 cultivar increased in response to UVB irradiation, despite no significant changes observed in lipid peroxidation, chlorophyll, and phenolic content. Additionally, UVB irradiation increases the total sugar content and decreases the entire free amino acid content, while not affecting total protein. The RT-qPCR analysis of mRNA expression reveals that UVB exposure augment the expression of genes related to UVB signal detection (UVR8), signalling (HY5, RLCK, and WRKY), and response (PHT2, CA, and URP). Our findings also suggest that at the post-transcriptional stage, miRNAs expressed upon UVB irradiation are responsible for the significant tolerance of IR20 seedlings to UVB radiation. Overall, the results reveal that IR20 exhibits promise candidate for the development of rice varieties that are both highly productive and resilient to UVB induced stress.

Elimination of damaged mitochondria during UVB-induced senescence is orchestrated by NIX-dependent mitophagy.

Skin aging is the result of two types of aging, "intrinsic aging" an inevitable consequence of physiologic and genetically determined changes and "extrinsic aging," which is dependent on external factors such as exposure to sunlight, smoking, and dietary habits. UVB causes skin injury through the generation of free radicals and other oxidative byproducts, also contributing to DNA damage. Appearance and accumulation of senescent cells in the skin are considered one of the hallmarks of aging in this tissue. Mitochondria play an important role for the development of cellular senescence, in particular stress-induced senescence of human cells. However, many aspects of mitochondrial physiology relevant to cellular senescence and extrinsic skin aging remain to be unraveled. Here, we demonstrate that mitochondria damaged by UVB irradiation of human dermal fibroblasts (HDF) are eliminated by NIX-dependent mitophagy and that this process is important for cell survival under these conditions. Additionally, UVB-irradiation of human dermal fibroblasts (HDF) induces the shedding of extracellular vesicles (EVs), and this process is significantly enhanced in UVB-irradiated NIX-depleted cells. Our findings establish NIX as the main mitophagy receptor in the process of UVB-induced senescence and suggest the release of EVs as an alternative mechanism of mitochondrial quality control in HDF.

IRE1α regulates ROS and immune responses after UVB irradiation

Objective UV irradiation of the skin induces photo damage and generates cytotoxic intracellular reactive oxygen species (ROS), activating the unfolded protein response (UPR) to adapt or reduce these UVB-mediated damages. This study was designed to understand the role of the UPR mediator IRE1α in the antioxidant response following UVB irradiation of mouse skin and keratinocytes. Methods We used mice with an epidermal deletion of IRE1α and primary mouse keratinocytes to examine effects of UV on different parameters of the antioxidant response in the presence and absence of functional IRE1α. Results In the absence of IRE1α, PERK activity and protein levels are significantly compromised following UVB irradiation. Additionally, the loss of IRE1α suppressed phosphorylation of the PERK target, nuclear factor erythroid-2-related factor 2 (NRF2), and NRF2-dependent antioxidant gene expression after UVB irradiation. Interestingly, IRE1α-deficient keratinocytes exhibit elevated basal ROS levels, while a robust ROS induction upon UVB exposure is abolished. Because UVB-induced ROS plays an essential role in regulating skin inflammation, we analyzed recruited immune cell populations and the expression of pro-inflammatory cytokines, Il-6 and Tnfα, in mice with epidermally targeted deletion of Ire1α. Following UVB irradiation, there was significantly less recruitment of neutrophils and leukocytes and reduced expression of pro-inflammatory cytokine genes in the skin of mice lacking IRE1α. Furthermore, keratinocyte proliferation was also significantly reduced after chronic UVB exposure in the skin of these mice. Conclusion Collectively, our findings indicate that IRE1α is essential for basal and UVB-induced oxidative stress response, UV-induced skin immune responses, and keratinocyte proliferation. Significance statement These findings shed new light on the protective function of IRE1α in the response to UV. IRE1α plays an important role in the regulation of ROS, PERK stability, and antioxidant gene expression in response to UVB in mouse keratinocytes and epidermis.

The isolation, structure characterizations and anti-photoaging activities of sulfated polysaccharides isolated from Sargassum fusiforme

BackgroundOur previous study found that crude polysaccharide extracted from Sargassum fusiforme (PSF) exhibited excellent anti-photoaging activity, but the composition responsible for this activity remained unknown.ResultsIn this study, three fractions (P1, P2 and P3) obtained by hot water extraction and column chromatographic separation from PSF were structurally characterized. The anti-photoaging activities of these isolated polysaccharides were evaluated using HaCaT cells. The results showed that P1, P2 and P3 were acidic polysaccharides with 42.94%, 40.75% and 2.21% uronic acid. In addition, the contents of sulfate groups were 3.01%, 10.05% and 7.44%, respectively. Moreover, their content of reducing sugar was low, and none of the fractions had a triple-stranded helical structure. P1 had the largest average molecular weight of 208.89 kDa, while P2 and P3 had a relatively lower molecular weight of 154.09 and 151.71 kDa, respectively. Treatment with P2 effectively safeguarded the viability of HaCaT cells exposed to UVB irradiation. Additionally, it inhibited the secretion of MMP-1 and MMP-3 while elevating the content of hydroxyproline (HYP) in the cell supernatant. Methylation and NMR analysis suggested the main structure of P2 might be → [4)-β-ManA-(1]23 → 4)-β-ManA-(1 → 3)-β-d-Glcp-(1 → 4)-β-d-Glcp-(1 → 4)-β-d-Glcp-(1 → . The two terminal groups of β-ManA-(1 → and β-d-Glcp-(1 → were connected via the glycosidic bonds of → 3, 4)-O-3 in β-ManA-(1 → and O-6 in → 4, 6)-β-d-Glcp-(1 → , respectively.ConclusionsThese findings will open new avenues for exploring the potential use of Sargassum fusiforme polysaccharide, particularly P2, as a functional ingredient with anti-photoaging activity.Graphical

MYB4, a member of R2R3-subfamily of MYB transcription factor functions as a repressor of key genes involved in flavonoid biosynthesis and repair of UV-B induced DNA double strand breaks in Arabidopsis

Plants accumulate flavonoids as part of UV-B acclimation, while a high level of UV-B irradiation induces DNA damage and leads to genome instability. Here, we show that MYB4, a member of the R2R3-subfamily of MYB transcription factor plays important role in regulating plant response to UV-B exposure through the direct repression of the key genes involved in flavonoids biosynthesis and repair of DNA double-strand breaks (DSBs). Our results demonstrate that MYB4 inhibits seed germination and seedling establishment in Arabidopsis following UV-B exposure. Phenotype analyses of atmyb4-1 single mutant line along with uvr8-6/atmyb4-1, cop1-6/atmyb4-1, and hy5-215/atmyb4-1 double mutants indicate that MYB4 functions downstream of UVR8 mediated signaling pathway and negatively affects UV-B acclimation and cotyledon expansion. Our results indicate that MYB4 acts as transcriptional repressor of two key flavonoid biosynthesis genes, including 4CL and FLS, via directly binding to their promoter, thus reducing flavonoid accumulation. On the other hand, AtMYB4 overexpression leads to higher accumulation level of DSBs along with repressed expression of several key DSB repair genes, including AtATM, AtKU70, AtLIG4, AtXRCC4, AtBRCA1, AtSOG1, AtRAD51, and AtRAD54, respectively. Our results further suggest that MYB4 protein represses the expression of two crucial DSB repair genes, AtKU70 and AtXRCC4 through direct binding with their promoters. Together, our results indicate that MYB4 functions as an important coordinator to regulate plant response to UV-B through transcriptional regulation of key genes involved in flavonoids biosynthesis and repair of UV-B induced DNA damage.

Magnolia biondii flower extract attenuates UVB-induced skin damage through high-mobility group box protein B1.

Magnolia biondii, a plant containing many magnolian-like compounds in its flowers or buds, exhibits anti-inflammatory and antiallergic effects; however, no study has addressed its effect on alleviating ultraviolet light (UV)-induced skin damage. We thus aimed at studying the effects of M. biondii flower extract (MB) on UVB-induced skin damage and determine the relationship between cell damage and damage-associated molecular patterns (DAMPs). Reconstructed epidermal models and foreskin samples were selected to detect cellular reactions after UVB irradiation and MB treatment. MTT, haematoxylin-eosin and immunofluorescence staining were used to examine total viability, sunburned cells and expression and migration of DAMPs at 16 or 48 h. Prostaglandin E2 (PGE-2) and interleukin 8 (IL-8) levels were measured using enzyme-linked immunosorbent assays. A clinical UVB-damaged test was carried out on human arms subjected to MB pre- or post-treatment. Human skin probes were used to measure erythema, melanin, ITA° and transepidermal water loss (TEWL), while skin photos were captured using the VISIA system. MB is rich in lignans such as magnolin, pinoresinol dimethyl ether and fargesin, and shows weak UV absorption at 280-320 nm. Coculturing with MB for 16 or 48 h after UVB irradiation improved the tissue viability and structure of Skinovo-Epi, and reduced the expression and migration of high mobility group box protein B1 (HMGB1) as well as the expression of IL-8 and PGE-2. In the excised foreskin treated with MB after UVB irradiation, the generation of 8-hidroxy-2-deoxyguanosine and nuclear transfer of HMGB1 were reduced. When pre-treated with MB for 3 days, UVB-induced skin erythema and ITA° were significantly decreased. When post-treated with MB for 5 days, a decrease in skin erythema, melanin and TEWL values and an increase in skin ITA° were observed. Treatment with MB attenuated UVB-induced skin damage, such as erythema, pigmentation and skin barrier function, by improving the tissue viability and structure and reducing sunburned cells and skin inflammation. This effect may be related to DNA damage, which causes the migration of HMGB1 from the nucleus to the outside of the cell to induce skin inflammation.

Mechanistic studies on protective effects of total flavonoids from Ilex latifolia Thunb. on UVB-radiated human keratinocyte cell line (HaCaT cells) based on network pharmacology and molecular docking technique.

The aim of the present research is to investigate anti-UVB radiation activity of total flavonoids from Ilex latifolia Thunb. (namely large-leaved Kuding tea) on human keratinocyte cell line (HaCaT cells) based on network pharmacology and molecular docking technique. Network pharmacology was used to screen target genes of active ingredients from Ilex latifolia Thunb. associated with UVB irradiation. The possible signaling pathways were analyzed by KEGG enrichment and verified by cellular experiments. Molecular docking was used to assess the affinity between the active ingredients and the core targets. The prediction of network pharmacology and molecular docking was identified by series experiment in UVB-irradiated HaCaT cells. Network pharmacology results showed that the active ingredients of Ilex latifolia Thunb. for anti-UVB irradiation were mainly flavonoids, and the possible signaling pathways were involved in PI3K-AKT, apoptosis, MAPKs, NF-κB, and JAK-STAT3. Molecular docking indicated key binding activity between AKT1-Glycitein, STAT3-Formononetin, CASP3-Formononetin, TNF-Kaempferol, CASP3-Luteolin, and AKT1-Quercetin. The total flavonoid pretreatment (0.25-1.0 mg/mL) down-regulated the expression of IL-6, IL-1β, and TNF-α in the cells determined by ELISA. The expression of phosphor PI3K, phosphor AKT, phosphor JAK, phosphor STAT3, phosphor JNK, and phosphor p38 MAPKs and COX-2 proteins in cytosolic and NF-κB p65 protein in nucleus were down-regulated and determined by western blot. It also protected UVB-irradiated cells from apoptosis by reducing apoptosis rate and down-regulating active-caspase 3. In a word, the total flavonoid treatment protected HaCaT cells from UVB injuries effectively, and the potential mechanism involves PI3K-AKT, JAK-STAT3, MAPK, and NF-κB pathway by anti-inflammatory and apoptosis action in cells. The mechanism invivo experiment needs to be further confirmed in future.

Differential fluorescence features and recovery speeds of different scorpion exoskeleton parts during the molting process

Scorpion fluorescence under ultraviolet light is a well-known phenomenon, but its features under excitation in the UVA, UVB and UVC bands have not been characterized. Systematic fluorescence characterization revealed indistinguishable fluorescence spectra with a peak wavelength of 475 nm for whole exuviae from second-, third- and fifth-instar scorpions under different ultraviolet light ranges. In-depth investigations of the chelae, mesosoma, metasoma and telson of adult scorpions further indicated heterogeneity in the typical fluorescence spectrum within the visible light range and in the newly reported fluorescence spectrum with a peak wavelength of 320 nm within the ultraviolet light range, which both showed excitation wavelength-independent features. Dynamic fluorescence changes during the molting process of third-instar scorpions revealed the fluorescence heterogeneity-dependent recovery speed of scorpion exoskeletons. The typical fluorescence spectra of the molted chelae and telson rapidly recovered approximately 6 h after ecdysis under UVA light and approximately 36 h after ecdysis under UVB and UVC light. However, it took approximately 12 h and 24 h to obtain the typical fluorescence spectra of the molted metasoma and mesosoma, respectively, under UVA irradiation and 72 h to obtain the typical fluorescence spectra under UVB and UVC irradiation. The fluorescence heterogeneity-dependent fluorescence recovery of the scorpion exoskeleton was further confirmed by tissue section analysis of different segments from molting third-instar scorpions. These findings reveal novel scorpion fluorescence features and provide potential clues on the biological function of scorpion fluorescence.

Structure characterization and protective effect against UVB irradiation of polysaccharides isolated from the plateau plant Gentiana dahurica Fisch

Gentiana dahurica Fisch. (G. dahurica) is one of the legitimate sources of Qinjiao in Traditional Chinese Medicine (TCM) and grows on high-altitude plateaus. Plants develop unique biochemical accumulations to resist plateau conditions, especially the strong UV irradiation. Thus, this study aimed to investigate the polysaccharide of G. dahurica (GDP), its structure and its activity against UVB irradiation. Four GDPs were isolated and two of them were subjected to structural elucidation. The results suggested that GDP-1 has 53.5 % Ara and 30.8 % GalA as its main monosaccharides, with a molecular weight (Mw) of 23 kDa; the GDP-2 has 33.9 % Ara and 48.5 % GalA, with a Mw of 82 kDa. Methylation and NMR spectroscopy analysis revealed that GDP-1 contains →5)-α-Araf-(1 → 5)-α-Araf-(1 → 3,5)-α-Araf-(1 → 3,4)-α-GalpA-(6-OMe)-(1→ as the main chain, the branches of GalA (with esterification), and the terminal Ara; the GDP-2 contains →4)-α-GalpA-(1 → 4)-α-GalpA-(6-OMe)-(1 → 5)-α-Araf-(1 → 3,5)-α-Araf-(1→ as the main chain, the branches of →5)-α-Araf-(1–5)-α-Araf, and the terminal GalA. Both GDP-1 and GDP-2 exhibited concentration-dependent antioxidant activity against DPPH, ABTS and hydroxyl radicals. Moreover, GDPs significantly attenuated the decreases in viability and proliferation of HaCaT cells after UVB irradiation. They can scavenge reactive oxygen species (ROS) and improve the activities of endogenous antioxidant enzymes, including superoxide dismutase (SOD) and glutathione peroxidase (GSH). The potential mechanism explored by flow cytometry assays of cell apoptosis and cell cycle distribution suggested that GDPs exert protective effects against UVB irradiation by reducing ROS and attenuating S phase cell arrest. In brief, the GDP-1 and GDP-2 are α-1,3- and α-1,4- arabinogalacturonan, respectively. The high content of Ara could be attributed to biochemical accumulation in resisting to the plateau environment and to prevent UVB irradiation-related damage in cells. These findings provide insight into authentic medicinal herbs and the development of GDPs in the modern pharmaceutical and cosmetics industry.

MiR-1246-overexpressing exosomes improve UVB-induced photoaging by activating autophagy via suppressing GSK3β.

Stem cell paracrine has shown potential application in skin wound repair and photoaging treatment. Our previous study demonstrated that miR-1246-overexpressing Exosomes (OE-EXs) isolated from adipose-derived stem cells (ADSCs) showed superior photo-protecting effects on UVB-induced photoaging than that of the vector, however, the underlying mechanism was unclear. The simultaneous bioinformatics analysis indicated that miR-1246 showed potential binding sites with GSK3β which acted as a negative regulator for autophagy. This study was aimed to explore whether OE-EXs ameliorate skin photoaging by activating autophagy via targeting GSK3β. The results demonstrated that OE-EXs significantly decreased GSK3β expression, enhanced autophagy flux and autophagy-related proteins like LC3II, while suppressed p62 expression. Meanwhile, OE-EXs markedly reversed the levels of intracellular ROS, MMP-1, procollagen type I and DNA damage in human skin fibroblasts caused by UVB irradiation, but the ameliorating effects were significantly inhibited when 3-Methyladenine (3-MA) was introduced to block the autophagy pathway. Further, OE-EXs could reverse UVB-induced wrinkles, epidermal hyperplasia, and collagen fibers reduction in Kunming mice, nevertheless, the therapeutical effects of OE-EXs were attenuated when it was combinative treated with 3-MA. In conclusion, OE-EXs could cure UVB induced skin photoaging by activating autophagy via targeting GSK3β.