UVB Exposure Research Articles

Genotoxic risk assessment of solar UV radiation in tadpoles from Brazilian wetlands

Solar ultraviolet (UV) radiation is an environmental genotoxic factor linked to amphibian decline. Here we assessed the genotoxic risk of UVB and UVA exposure for tadpoles from open ponds in southern Brazil, a mid-latitude region influenced by stratospheric ozone depletion. Daily UV doses were measured on the surface of a pond in Taim Ecological Station (TAIM; 32°49’24’’S; 52°38’31’’W) on a cloudless summer day to predict the worst-case scenario for UV-induced DNA damage. Pond descriptors were related to the use of microhabitats by Boana pulchella tadpoles in two ponds over the climate seasons of 2013 and 2014. Our results indicate that shaded microhabitats were more frequent than unshaded ones in autumn, winter, and spring but not in summer. Hence, the penetration of UV radiation into the water of unshaded microhabitats was evaluated through laboratory experiments with artificial UV sources and pond water samples. Physical and biological sensors were applied in the experiments to measure the incident UV radiation and its genotoxic action. By integrating field and laboratory data, we demonstrate that low doses of biologically effective UV radiation reached the tadpoles in autumn, winter, spring, and early summer due to a high proportion of shaded microhabitats and a high concentration of solids in unshaded microhabitats. However, the relative reduction of shaded microhabitats jointly with a declining water level in late summer may have exposed tadpoles to high UV doses. Our experiments also indicate that solar UVB radiation, but not UVA, is primarily responsible for the induction of DNA pyrimidine dimers in organisms living under the surface of aquatic ecosystems. The present work highlights the determinant role of wetland descriptors for minimizing the genotoxic potential of UV radiation and its consequences for amphibians.

Enhanced Spontaneous Skin Tumorigenesis and Aberrant Inflammatory Response to UVB Exposure in Immunosuppressed Human Papillomavirus Type 8‒Transgenic Mice

Human papillomaviruses (HPVs) from the beta genus are commensal viruses of the skin usually associated with asymptomatic infection in the general population. However, in individuals with specific genetic backgrounds, such as patients with epidermodysplasia verruciformis, or those with immune defects, such as organ transplant recipients, they are functionally involved in sunlight-induced skin cancer development, mainly keratinocyte carcinoma. Despite their well-established protumorigenic role, the cooperation between β-HPV infection, impaired host immunosurveillance, and UVB exposure has never been formally shown in animal models. In this study, by crossing skin-specific HPV8-transgenic mice with Rag2-deficient mice, we have generated a preclinical mouse model, named Rag2‒/‒:K14-HPV8. These mice display an unhealthy skin phenotype and spontaneously develop papilloma-like lesions spreading to the entire skin much more rapidly compared with Rag2+/+:K14-HPV8 mice. Exposure to low doses of UVB radiation is sufficient to trigger severe skin inflammation in Rag2‒/‒:K14-HPV8 but not in Rag2+/+:K14-HPV8 mice. Their inflamed skin very much resembled that observed in cutaneous field cancerization in organ transplant recipients, showing high levels of UVB-damaged cells, enhanced production of proinflammatory cytokines, and mast cell recruitment to the dermis. Overall, this immunocompromised HPV8-transgenic mouse model shows that the coexistence of immune defects, β-HPV, and UVB exposure promotes skin cancer development.

Nicotinamide and calcipotriol counteract UVB-induced photoaging on primary human dermal fibroblasts

BackgroundPhotoaging is mainly caused by ultraviolet radiations inasmuch they can damage the DNA, trigger ROS production, and activate p53/p21 pathway, which cause cell cycle arrest and senescence. The accumulation of senescent cells within the dermis contributes to tissue deregulation and skin carcinogenesis. However, the use of photoprotector molecules could reduce UV-induced damages and prevent photoaging. Therefore, the aim of this study is to evaluate whether the active forms of vitamin B3 (nicotinamide) and the analog of vitamin D3 (calcipotriol) might protect primary human dermal fibroblasts (HDFs) from UVB-induced photoaging. MethodsHDFs were isolated from a healthy adult donor and stimulated with nicotinamide (25 μM) and calcipotriol (100 nM) for 24h before UVB exposure, and then, cultured for further 24h on vitamin-supplemented media. Then, cell viability, ROS production, DNA damages, senescence markers, protein and gene expression were evaluated. ResultsHDFs treated with nicotinamide and calcipotriol showed better proliferation properties and lower DNA damages due to a reduced UVB-induced ROS production. Consequently, p53/p21 pathway was less active which enhanced cell cycle progression and reduced senescence and cell death. ConclusionsOverall, our results suggest that nicotinamide and calcipotriol can counteract UVB-induced effects responsible for the onset of skin photoaging.

Trigonelline, a plant derived alkaloid prevents ultraviolet-B-induced oxidative DNA damage in primary human dermal fibroblasts and BALB/c mice via modulation of phosphoinositide 3-kinase-Akt-Nrf2 signalling axis

BackgroundDNA is the main target for UV-B-irradiation-induced skin photodamage and accounts for 90 % of all the non-melanoma skin cancers. PurposeIn this study, we explored the mechanistic basis of photoprotective effect of Trigonelline, a naturally occurring alkaloid from the Trigonella foenum-graecum, against UV-B-induced oxidative DNA Damage Response using Primary Human Dermal Fibroblasts (HDFs) and BALB/C mice as models of skin photodamage. MethodsPrimary HDFs were subjected to UV-B exposure (10 mJ/cm2) with or without TG for 24 h. Effect of UV-B exposure and TG treatment was evaluated by analyzing the cell survival, cellular morphology, oxidative stress & DNA damage response markers by performing biochemical studies, florescent microscopy & protein expression studies. In in-vivo study, TG pre-treated BALB/c mice were -irradiated with 180 mJ/cm2 of UV-B dose thrice a week on alternative days for four months, followed by topical application of different concentrations of TG. The photodamage caused by UV-B exposure and its ameleoriation by topical treatment of TG was studied by physical and morphological appearance and analyzing the oxidative stress & DNA damage response markers from skin. ResultsWe found that TG significantly alleviates UV-B–induced cell death effects in HDFs. TG protects HDF cells and BALB/c mice from UV-B-induced DNA damage by regulating the expression profile of key protein markers of DNA damage which include P53, ATM, ATR, ϒH2AX, Chk1 and Chk2. We found that TG offers geno-protection to UV-B–irradiated HDFs by alleviating CPD induction, reducing the number of TUNEL positive cells and by decreasing the expression levels of DNA damage marker protein ϒH2AX in immunocytochemistry. Further, we found that TG prevents the UVB induced oxidative stress by activating the PI3K-AKT-Nrf2 signalling pathway. On employing PI3K inhibitor, LY294002, we found the expression of ϒH2AX and p-P53 is significantly increased compared to UV-B treated only, indicating that TG mediates the geno-protection against UV-B irradiation via PI3K-AKT-Nrf2 signalling pathway. ConclusionCurrent study presents for the first time the photo-protective role of TG against UV-B–induced oxidative DNA damage and provides its mechanistic insights also and provide strong evidence for TG to be carried forward as a potential remedial and cosmeceutical agent against UV-B–induced skin photodamage disorders.

Novel ocular immunotherapy induces tumor regression in an equine model of ocular surface squamous neoplasia.

Ocular surface squamous neoplasia (OSSN) is the major cause of corneal cancer in man and horses worldwide, and the prevalence of OSSN is increasing due to greater UVB exposure globally. Currently, there are no approved treatments for OSSN in either species, and most patients are managed with surgical excision or off-label treatment with locally injected interferon alpha, or topically applied cytotoxic drugs such as mitomycin C. A more broadly effective and readily applied immunotherapy could exert a significant impact on management of OSSN worldwide. We therefore evaluated the effectiveness of a liposomal TLR complex (LTC) immunotherapy, which previously demonstrated strong antiviral activity in multiple animal models following mucosal application, for ocular antitumor activity in a horse spontaneous OSSN model. In vitro studies demonstrated strong activation of interferon responses in horse leukocytes by LTC and suppression of OSSN cell growth and migration. In a trial of 8 horses (9 eyes), treatment with topical or perilesional LTC resulted in an overall tumor response rate of 67%, including durable regression of large OSSN tumors. Repeated treatment with LTC ocular immunotherapy was also very well tolerated clinically. We conclude therefore that ocular immunotherapy with LTC warrants further investigation as a novel approach to management of OSSN in humans.

Effect of Narrowband UV-B Irradiation on the Growth Performance of House Crickets.

Indoor co-cultivation systems can answer to the need for sustainable and resilient food production systems. Rearing organisms under light-emitting diodes (LEDs) irradiation provides the possibility to control and shape the emitted light spectra. UV-B-irradiation (280-315 nm) can positively affect the nutritional composition of different plants and other organisms, whereas information on edible insects is scarce. To evaluate the potential effect of the photosynthetically active radiation (PAR) and LED-emitting LEDs on the rearing and nutritional quality of edible insects, house crickets (Acheta domesticus) were reared from the age of 21 days under controlled LED spectra, with an additional UV-B (0.08 W/m2) dose of 1.15 KJm2 d-1 (illuminated over a period for 4 h per day) for 34 days. UV-B exposure showed no harm to the weight of the crickets and significantly increased their survival by ca. 10% under narrowband UV-B treatment. The nutritional composition including proteins, fat and chitin contents of the insects was not affected by the UV-B light and reached values of 60.03 ± 10.41, 22.38 ± 2.12 and 9.33 ± 1.21%, respectively, under the LED irradiation. Therefore, house crickets can grow under LED irradiation with a positive effect of narrowband UV-B application on their survival.

자운영 에탄올 추출물이 인간 진피 섬유아세포에 미치는 노화 방지 효과

Background: Skin aging is caused by two factors: Intrinsic factors such as genetics and extrinsic factors such as ultraviolet exposure. This study aimed to explore the ameliorating activity of ethanol extract of Astragalus sinicus (ASE) on human skin fibroblast (HDFs) subjected to intrinsic and extrinsic aging via continuous culturing and UVB radiation, respectively.BRMethods and Results: Matrix metalloproteinase (MMP-1) mRNA expression and elastase activity were determined using qRT-PCR and ELISA, respectively. The activities of senescence-associated β-galactosidase (SA-β-gal) with or without UVB exposure were investigated using enzyme histochemical staining assay. ASE treatment decreased MMP-1 expression and elastase activity. Furthermore, ASE treatment suppressed SA-β-gal activity in both UVB-exposed and UVB-free environments.BRConclusions: These finding suggest that ASE has dermal anti-aging effects and can be employed as a functional cosmetic material.

Glucose starvation impairs NER and γ-H2AX after UVB irradiation

Glucose is the major source for energy production. As tumor cells have higher glucose requirement, combination of glucose restriction and radio- and chemo-therapy has been explored. In this study, impairment of UVB-induced DNA damage repair response (DDR) by glucose starvation was revealed. Human keratinocytes and skin carcinoma cells were cultured in medium containing 0, 2.5, 5.5 and 25 mM glucose. Glucose restriction suppressed cell proliferation and histone acetylation. UVB exposure formed similar levels of pyrimidine dimers in all glucose conditions, whereas the repair tended to be delayed in low glucose medium. The repair molecules, TFIIH and XPG, were accumulated to DNA damaged sites regardless of glucose supply levels, but the release was delayed in glucose-starved cells. The remaining pyrimidine dimers would induce the collapse of replication forks during S phase, resulting in phosphorylation of histone H2AX (γ-H2AX), but the γ-H2AX in cells cultured in glucose-deleted medium was unexpectedly decreased. This might be due to the suppression of DNA replication by glucose deletion. This was further confirmed by the decrease in the formation of DNA double strand breaks in glucose-starved cells. These results suggested that condition of energy supply might affect UV-induced DDR.

GSDME deficiency leads to the aggravation of UVB-induced skin inflammation through enhancing recruitment and activation of neutrophils

Gasdermin E (GSDME)-mediated pyroptosis is induced in keratinocytes of UVB-challenged skin. The role of GSDME in UVB-caused skin damage remains unknown. To explore the role of GSDME in UVB-induced skin inflammation. We compared differences in skin appearance, histological features, keratinocyte death modalities, infiltration of immune cells, and levels of some inflammatory cytokines between Gsdme−/− mice and wild type (WT) mice after UVB exposure. We explored whether keratinocytes contribute to GSDME deficiency-caused aggravation of UVB-induced skin inflammation in GSDME knockdown keratinocyte cultured in vitro and keratinocyte-specific Gsdme conditional knockout mice. We used anti-Ly6G antibody to deplete neutrophils and explore their role in UVB-caused skin damage. Skin damage and neutrophils infiltration were aggravated in UVB-challenged Gsdme−/− mice, compared with UVB-challenged WT mice. Apoptosis and necroptosis, which were initiated together with GSDME-mediated pyroptosis in UVB-challenged WT mice, were not enhanced in UVB-challenged Gsdme−/− mice. Neutrophils activation indicators and its recruiting cytokines were increased in skin tissue of UVB-challenged Gsdme−/− mice. However, GSDME knockdown did not lead to the further increase of mRNA and secretion of TNF-α and IL-6 in UVB-challenged keratinocytes. Skin damage was not aggravated in UVB-challenged Gsdme cKO mice. Neutrophils depletion alleviated UVB-caused skin damage in WT mice and Gsdme−/− mice, and eliminated its aggravation in Gsdme−/− mice. This study demonstrates that GSDME plays a restrictive role in UVB-induced skin damage through inhibiting excessive recruitment and activation of neutrophils in the immune microenvironment in UVB-caused skin inflammation. However, keratinocytes might not contribute to this restrictive function.

Pretreatment of mosquito larvae with ultraviolet-B and nitropolycyclic aromatic hydrocarbons induces increased sensitivity to permethrin toxicity

Nitropolycyclic aromatic hydrocarbons (Nitro-PAH) are highly toxic PHA derivatives. Nitro-PHAs are emitted by carbonaceous materials and PHA post-emission transformation, which causes water and environmental pollution and also exists as carcinogenic and immunotoxic agents. UV light has been shown to cause DNA damage and improves the covalent binding of PAH to DNA significantly. Mosquito breeding grounds are pools of water that can be large open zones or encased ponds with varying levels of sunlight exposure. This research was performed to assess the combined effects of UV-B exposure and Nitro-PAH on the physiological function of Culex quinquefasciatus larvae. To assess the impact of UV-B irradiation and Nitro-PAH exposure on mosquito vectors, parameters were examined: (1) Nitro-PAH availability and its impact on cell fatalities; (2) the detoxifying abilities of cytochrome P450, glutathione-S-transferase, and esterase; (3) the reactions to Reactive Oxygen Species; and (4) The resistance of mosquito larvae to three synthetic pesticides (temephos, imidacloprid, and permethrin). UV-B and Nitro-PAH treatment caused cellular damage and increased major detoxification enzymes such as α & β-esterase, cytoP450, CAT, GST, and POX. The levels of oxidative stress, ROS and protein carbonyl content, nitrite, ascorbic acid and thiobarbituric acid were decreased significantly. Toxicology bioassays revealed that UV-B + Nitro-PAH exposure significantly increased larval susceptibility. The current study concludes that prior exposure to Nitro-PAHs and UV-B may make mosquito larvae more vulnerable to chemical insecticides.

Construction of a Secondary Enclosure for UVB Irradiation of Mice

UV irradiation is commonly used in murine models of skin cancers. Despite the popularity of using UVB rays to model photocarcinogenesis in animals, there is a lack of standardization in the secondary enclosures used to administer radiation. An appraisal of the literature also shows a general lack of details regarding the materials and procedures utilized in the fabrication of such enclosures. We present in this study a detailed overview of the construction of a UVB exposure chamber that successfully induces lesions in hairless mice. A standardized protocol for producing a UVB enclosure may reduce methodological variation in future studies seeking to investigate photocarcinogenesis in animals.

The Protective Effects of Sodium Pentaborate Tetrahydrate Against UVB-induced Apoptosis in Human Keratinocytes

Ultraviolet radiation (UV) is an environmental carcinogen causing human skin cancer. Exposure of the skin to UV produces apoptotic keratinocytes called sunburn cells within the epidermis. Boron, an essential element for plants, has several biological properties, such as anti-cancer, anti-microbial, and anti-oxidant. In the present study, the possible protective effects of sodium pentaborate pentahydrate (SPT) against UVB-induced apoptosis in human keratinocyte cells, HaCaT, were investigated. They were treated with SPT at different concentrations (7.8-125 μg/mL) for 24h after UVB irradiation (20, 30 and 60mJ/cm2). Cell viability, annexin V assay, cell cycle analysis, and apoptosis-related gene levels were measured using RT-PCR. Treatment with SPT (15.6-31.25μg/mL) after 30 mJ/m2 UVB exposure significantly increased cell survival. Annexin V apoptosis analysis demonstrated a robust protective effect by treatment with SPT at concentrations of 15.6 and 31.25μg/mL after 30mJ/cm2 UVB irradiation. The cell cycle analysis revealed that UVB irradiation elevated the number of cells at the G0/G1 phase while SPT treatment after UVB irradiation increased the number of cells at G2/M phase, suggesting the changes were partially reversed. Furthermore, treatment with 15.6μg/mL SPT after 30 mJ/m2 UV irradiation blocked the activation of caspase 3, caspase 9, Bax, and p53. These results indicate that treatment with SPT exerts protective effects after UVB irradiation. Thus, treatment with SPT led to strong protection against UVB-induced apoptotic cell death in HaCaT cells.

UV-induced skin's green autofluorescence is a biomarker for both non-invasive evaluations of the dosages of UV exposures of the skin and non-invasive prediction of UV-induced skin damage.

It is crucial to discover biomarkers for non-invasive evaluations of the dosages of UV exposures to a person during post-UV exposure period, and for non-invasive prediction of UV-induced skin damage. Our current study has obtained findings: UVB exposures produced dose-dependent increases in skin's green autofluorescence (AF) intensity of mice, which were significantly associated with the UVB dosages. The UVC-induced green AF increases were dose dependent, which were highly associated with the UVC dosages. Moreover, both previous reports and our current study have collectively shown significant association between UVB/UVC dosages and UVB/UVC-induced skin damage. Collectively, our study has indicated that the UVB/UVC-induced skin's AF are first biomarkers for both non-invasive evaluations of the dosages of UV exposures to a person during post-UV exposure period and non-invasive and label-free prediction of UVB/UVC-induced skin damage.

Transcriptional changes in the gilthead seabream (Sparus aurata) skin in response to ultraviolet B radiation exposure

Solar ultraviolet B radiation (UVB) has recently been described as a relevant stressor in fish confined to aquaculture cages. In gilthead seabream (Sparus aurata), UVB exposure resulted in decreased growth, epidermal sloughing, increased oxidative stress in the skin, and induced changes in behavior, physiology, and immune system. Several molecular responses should accompany such detrimental effects; however, little is known in fish about the overall UVB-mediated changes at the transcriptional level. Thus, this study aimed to investigate the effects of UVB exposure on the global gene expression profiles of S. aurata skin through transcriptome analysis. S. aurata juveniles were exposed for 43 days to two experimental groups: 1) UVB (daily dose, 6 kJ m-2; representing levels between 5 and 7 m depth); 2) Unirradiated treatment, used as a control. The comparison of skin transcriptomes between the control and UVB treatments revealed 845 differentially expressed genes (580 up-regulated and 265 down-regulated). The reliability of the transcriptome analysis was confirmed by qRT-PCR for selected genes. Functional annotation and PPI analyses revealed that genes related to the immune system and inflammatory response, cell cycle regulation, proteasome, proteolysis, and oxidative stress might be involved in the response to UVB exposure. In contrast, UVB exposure inhibited the expression of several genes related to growth factor activity, cell growth and differentiation, and pigmentation. p53 signaling pathway was enriched in fish exposed to UVB. Moreover, pathways involved in the immune system and inflammatory response (cytokine-cytokine receptor interaction, RIG-I-like receptor signaling pathway, and Toll-like receptor signaling pathway) were also enriched in the skin of UVB-exposed fish. UVB-induced skin damage and a high level of infiltration of immune-related cells were confirmed through histopathological examination. Together, our results provide noteworthy insights into the molecular changes in fish after long-term exposure to UVB. These findings will help in the future to identify biomarkers of fish reared in offshore aquaculture systems in oligotrophic and highly transparent waters.

Beneficial Effect of Gastrodia elata Blume and Poria cocos Wolf Administration on Acute UVB Irradiation by Alleviating Inflammation through Promoting the Gut-Skin Axis.

Bioactive compounds in some herbs can, directly and indirectly, protect against photoaging. We evaluated the effects of Gastrodia elata Blume (GE) and Poria cocos Wolf (PC) water extracts on ultraviolet (UV) B-induced skin lesions by acute UVB exposure in ICR mice and explored their mechanism of action. After removing the hair on the back of the mice, UVB (280–310 nm) was exposed to the back for 30 min to induce skin damage. Four UVB exposure groups were divided into the following according to the local application (1,3-butanediol extract) on the dorsal skin and oral intake (0.3 g water extract/kg body weight/day): 1,3-butanediol and cellulose(control; UV-Con), retinoic acid (positive-control; UV-Positive), PC extracts (UV-PC), and GE extracts (UV-GE). The fifth group had no UVB exposure with the same treatment as the UV-Con (Normal-control). The erythema, burns, erosion, and wounds of the UV-PC and UV-PC groups were alleviated, and the most significant improvements occurred in the UV-PC group. PC and GE reduced the thickness of the dorsal skin tissue, the penetration of mast cells, and malondialdehyde contents. The mRNA expression of TNF-α, IL-13, and IL-4, inflammatory factors, were also reduced significantly in the dorsal skin of the UV-PC and UV-GE groups. UV-PC, UV-GE, and UV-Positive showed improvements in UV-induced intestinal tissue inflammation. UV-Con deteriorated the intestinal morphology, and PC and GE alleviated it. The α-diversity of the fecal microbiota decreased in the UV-control, and UV-PC and UV-GE prevented the decrease. Fecal metagenome analysis revealed increased propionate biosynthesis in the UV-PC group but decreased lipopolysaccharide biosynthesis in the UV-PC and UV-GE groups compared to UV-Con. In conclusion, the local application and intake of PC and GE had significant therapeutic effects on acute UV-induced skin damage by reducing oxidative stress and proinflammatory cytokines, potentially promoting the gut-microbiota-gut-skin axis.

RUP2 facilitates UVR8 redimerization via two interfaces

The plant UV-B photoreceptor UV RESISTANCE LOCUS 8 (UVR8) exists as a homodimer in its inactive ground state. Upon UV-B exposure, UVR8 monomerizes and interacts with a downstream key regulator, the CONSTITUTIVE PHOTOMORPHOGENIC 1/SUPPRESSOR OF PHYA (COP1/SPA) E3 ubiquitin ligase complex, to initiate UV-B signaling. Two WD40 proteins, REPRESSOR OF UV-B PHOTOMORPHOGENESIS 1 (RUP1) and RUP2 directly interact with monomeric UVR8 and facilitate UVR8 ground state reversion, completing the UVR8 photocycle. Here, we reconstituted the RUP-mediated UVR8 redimerization process in vitro and reported the structure of the RUP2-UVR8W285A complex (2.0 Å). RUP2 and UVR8W285A formed a heterodimer via two distinct interfaces, designated Interface 1 and 2. The previously characterized Interface 1 is found between the RUP2 WD40 domain and the UVR8 C27 subregion. The newly identified Interface 2 is formed through interactions between the RUP2 WD40 domain and the UVR8 core domain. Disruption of Interface 2 impaired UV-B induced photomorphogenic development in Arabidopsis thaliana. Further biochemical analysis indicated that both interfaces are important for RUP2-UVR8 interactions and RUP2-mediated facilitation of UVR8 redimerization. Our findings suggest that the two-interface-interaction mode is adopted by both RUP2 and COP1 when they interact with UVR8, marking a step forward in understanding the molecular basis that underpins the interactions between UVR8 and its photocycle regulators.

Alpinia officinarum Rhizome ameliorates the UVB induced photoaging through attenuating the phosphorylation of AKT and ERK

BackgroundChronic ultraviolet (UV) exposure is one of the major external factors in skin aging, and repetitive UVB exposure induces extracellular matrix (ECM) damage as well as metabolic disease. Alpinia officinarum Rhizome (AOR) is a medicinal plant that has been traditionally used for treating rheumatism and whooping cough. However, the antiphotoaging effects of AOR remain unclear. We investigated the protective effects of water extracts of AOR (WEAOR) in terms of UVB-mediated ECM damage, wrinkle formation, inflammatory responses, and intracellular signaling on hairless mice and NIH-3T3 skin fibroblast cells.MethodsWEAOR was administered to UVB-irradiated hairless mice. Wrinkle formation was assessed using the replica assay, epidermal changes through H&E staining, and collagen contents in mice skin through Masson’s trichrome staining. The expression of procollagen type-1 (COL1A1), metalloproteinase-1a (MMP-1a), and inflammatory cytokines (IL-6, IL-8, and MCP-3) in hairless mice skin and NIH-3T3 cells was investigated through qRT-PCR. The effects of WEAOR or signaling inhibitors on UVB-induced expression of intracellular mitogen-activated protein kinases (MAPKs) were estimated by Western blotting and qRT-PCR, respectively.ResultsTopical WEAOR significantly attenuated the UVB-induced wrinkle formation and epidermal thickening in the skin of hairless mice. WEAOR treatment also attenuated the UVB-induced expression of MMP-1a and COL1A1 and recovered the reduction of collagen content in mouse skin. These effects were confirmed in NIH-3T3 skin fibroblast cells. WEAOR treatment restored the UVB-induced COL1A1 and MMP-1a gene expression and attenuated the UVB-induced expression of IL-6, IL-8, and MCP-3 in NIH-3T3 cells. Notably, WEAOR attenuated UVB-induced phosphorylation of AKT and ERK, but not that of p38 and JNK in NIH-3T3 cells. In addition, the administration of AKT and ERK inhibitors restored the UVB-induced expression of MMP-1a and COL1A1 to an equal extent as WEAOR in NIH-3T3 cells.ConclusionsThe antiphotoaging properties of WEAOR were first evaluated in this study. Our results suggest that WEAOR may be a potential antiphotoaging agent that ameliorates UVB-induced photoaging processes via the AKT and ERK signaling pathways.

Pyrimethamine induces phototoxicity in human keratinocytes via lysosomal and mitochondrial dependent signaling pathways under environmental UVA and UVB exposure

Pyrimethamine (PYR) is used to treat parasitic infections including toxoplasmosis, pneumonia and cystoisosporiasis in HIV patients. Various oral medicines have shown phototoxicity therefore, we aimed to study the phototoxicity of PYR and its molecular mechanism involving stress responsive lysosomal protein Lamp2 and mitochondrial mediated signaling pathway under normal UVA/B exposure. We found that photodegradation and subsequent photoproduct formation was evident through LCMS/MS analysis. Photosensitized PYR produces ROS that cause damage to DNA, cell membrane and membrane bound organelles in human keratinocytes. PYR triggered cytotoxicity and phototoxicity that was evident through MTT and NRU assay respectively. Intracellular ROS generation caused phosphatidyl serine (PS) translocation in cell membrane, lysosome membrane permeabilization (LMP) and mitochondrial membrane potential (MMP) collapse that was further validated through caspase3 activation. DNA damage was measured as tail DNA formation and cell cycle arrest in G1 phase. Photosensitized PYR induces oxidative stress in the form of overexpression of Lamp2 that ultimately led to cellular apoptosis. Moreover, the effects of UVB were higher than UVA, probably due to its direct interaction with various macromolecules. We propose that photoexcited PYR may be harmful to human health even at normal sunlight exposure. Therefore, protective procedures should be practiced during PYR medication.

KDM1A inhibition increases UVA toxicity and enhances photodynamic therapy efficacy.

Lysine-specific histone demethylase 1 (KDM1A/LSD1) regulates multiple cellular functions, including cellular proliferation, differentiation, and DNA repair. KDM1A is overexpressed in squamous cell carcinoma of the skin and inhibition of KDM1A can suppress cutaneous carcinogenesis. Despite the role of KDM1A in skin and DNA repair, the effect of KDM1A inhibition on cellular ultraviolet (UV) response has not been studied. The ability of KDM1A inhibitor bizine to modify cell death after UVA and UVB exposure was tested in normal human keratinocytes and melanocytes, HaCaT, and FaDu cell lines. KDM1A was also downregulated using shRNA and inhibited by phenelzine in HaCaT and FaDu cells to confirm the role of KDM1A in UVA response. In addition, cellular reactive oxygen species (ROS) changes were assessed by a lipid-soluble fluorescent indicator of lipid oxidation, and ROS-related gene regulation using qPCR. During photodynamic therapy (PDT) studies HaCaT and FaDu cells were treated with aminolaevulinic acid (5-ALA) or HPPH (2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a) sodium and irradiated with 0-8J/cm2 red LED light. KDM1A inhibition sensitized cells to UVA radiation-induced cell death but not to UVB. KDM1A inhibition increased ROS generation as detected by increased lipid peroxidation and the upregulation of ROS-responsive genes. The effectiveness of both ALA and HPPH PDT significantly improved in vitro in HaCaT and FaDu cells after KDM1A inhibition. KDM1A is a regulator of cellular UV response and KDM1A inhibition can improve PDT efficacy.

Sun Bathing Affects Overweight-Obese Subjects Vitamin D Deficiency

Background: There are increasing number of studies that discuss the effect of sun exposure to overweight and obese individuals with vitamin D deficiency (which is UVB exposure can increase serum 25-Hydroxyvitamin D levels). However, until now there is no a literature review about these studies. This shows a weak correlation between sun bathing and serum 25-Hydroxyvitamin D elevation in overweight and obese people. Aim: Describe the effect of the sun bathing for overweight-obese patient with vitamin D deficiency. Material and Methods: Electronic searching tools (ScienceDirect, Pubmed, and Google Scholar) were conducted from the 1990s until the recent literature. A sensitive search strategy uses specific terms. Studies were included if the population with BMI > 25 Kg/m2; Sun Exposure intervention, the studies provided the comparison of implementation method, the studies provided 25-Hydroxyvitamin D status as the outcome. For the exclusion criteria: studies that included subjects metabolics syndrome. MMAT was used for eliminating biased research. Results: Two studies were fulfilled our inclusion criteria. The studies, were excluded, mainly because they lacked data, biased reseach, and failure to answer any authors questions. Conclusion: The sun exposure method has a positive corellation for increasing serum 25-Hydroxyvitamin D level in overweight and obese subjects with vitamin D deficiency, but internal factors (age and skin color) and external factors (season, temperature, dose, and duration) need to be considered to get effective result. Keywords: Obese, Overweight, Sun bathing, Vitamin D deficiency, 25-Hydroxyvitamin D.