Anti-Phototoxicity Effect of Phenolic Compounds from Acetone Extract of Entada phaseoloides Leaves via Activation of COX-2 and iNOS in Human Epidermal Keratinocytes.

The extract from Entada phaseoloides was employed as active ingredients of natural origin into cosmetic products, while the components analysis was barely reported. Using LC-DAD-MS/qTOF analysis, eleven compounds (1-11) were proposed or identified from acetone extract of E. phaseoloides leaves (AE). Among them, six phenolic compounds, protocatechuic acid (2), 4-hydroxybenzoic acid (3), luteolin-7-O-ß-d-glucoside (5), cirsimaritin (6), dihydrokaempferol (9), and apigenin (10), were isolated by various chromatographic techniques. Protocatechuic acid (2), epicatechin (4), and kaempferol (11) at a concentration 100 µM increased the HaCaT cells viability of the UVB-irradiated cell without any cytotoxicity effect and reduced the expression of COX-2 and iNOS inflammation gene. Moreover, compounds 2 and 4 could have potent effects on cell migration during wound closure. These results suggest that compounds 2, 4, and 11 from AE have anti-photoaging properties and could be employed in pharmaceutical and cosmeceutical products.

Trehangelins ameliorate inflammation-induced skin senescence by suppressing the epidermal YAP-CCN1 axis.

Trehangelins (THG) are newly identified trehalose compounds derived from broth cultures of an endophytic actinomycete, Polymorphospora rubra. THG are known to suppress Cellular Communication Network factor 1 (CCN1), which regulates collagen homeostasis in the dermis. Although the physical properties of THG suggest a high penetration of the stratum corneum, the effect of THG on the epidermis has not been reported. Here we describe a possible mechanism involved in skin aging focusing on the effect of THG on epidermal CCN1. This study shows that: (1) THG suppress epidermal CCN1 expression by inhibiting the translocation of Yes-Associated Protein (YAP) to nuclei. (2) Epidermal CCN1, localized at the basement membrane, regulates the balance between the growth and differentiation of keratinocytes. (3) Keratinocytes secrete more CCN1 than fibroblasts, which leads to disruption of the basement membrane and extracellular matrix components. (4) The secretion of CCN1 from keratinocytes is increased by ultraviolet B exposure, especially in aged keratinocytes, and deteriorates the elastic fiber structures in the underlying dermis. (5) Topical application of THG ameliorates the structure of the basement membrane in ex vivo human skin explants. Taken together, THG might be a promising treatment for aged skin by suppressing the aberrant YAP-CCN1 axis.

Evaluation and enzyme-aided enhancement of anti-photoaging properties of Camellia japonica in UVA-irradiated keratinocytes.

Exposure to ultraviolet (UV) radiation is the main reason behind extrinsic skin aging. Changes due to chronic UV exposure are called photoaging. Natural products are effective ingredients against UV-mediated skin damage. Present study investigated the anti-photoaging properties of Camellia japonica flowers which possess various bioactivities. To enrich the extracts of C. japonica flowers, pectinase and beta-glucosidase treatment was employed. Anti-photoaging effect was screened using the changes in MMP-1 and collagen levels in UVA-irradiated human HaCaT keratinocytes. The crude extract of C. japonica flowers (CE) was shown to decrease the UVA-induced MMP-1 secretion while attenuating the collagen levels. Pectinase and beta-glucosidase treated CE (ECE) showed increased anti-photoaging effects against UVA-induced changes in MMP-1 and collagen production. Camellenodiol (CMD), a known triterpenoid from C. japonica, isolated as the active ingredient of ECE and its anti-photoaging effect was screened. Results showed that CMD ameliorated the UVA-induced deterioration in collagen levels by suppressing MMP-1 production in transcriptional level. CMD treatment downregulated the phosphorylation of p38, ERK, and JNK MAPKs along their downstream effectors, c-Fos, and c-Jun. In conclusion, enzyme-assisted extraction of C. japonica flowers was suggested to enhance the anti-photoaging properties suggestively through high bioactive content such as CMD.

Stress-induced miRNAs isolated from wheat have a unique therapeutic potential in ultraviolet-stressed human keratinocyte cells.

Increasing evidence supports the existence of cross-kingdom gene regulation. However, the therapeutic potential of stress-specific plant miRNAs and their role in UV-related pathologies in human tissue remain largely unexplored. The aim of this study was to investigate the therapeutic potential and mechanisms of action of stress-induced miRNA cocktails (SI-WmiRs) from Einkorn wheat (Triticum monococcum L.) on human keratinocyte (HaCaT) cells exposed to a high dose of UV-B radiation. We used a biofactory approach and irradiated wheatgrass with UV-C for 240 min to obtain the specific SI-WmiRs that wheat produces to recover from UV stress. We followed the plant with molecular and biochemical analyses and extracted our SI-WmiRs at the most appropriate time (0 h and 6 h after UV-C application). Then, we applied the SI-WmiR cocktail to HaCaT cells exposed to high-dose of UV-B radiation. Our results show that UV-B radiation induced lipid peroxidation and DNA damage, as demonstrated by increased malondialdehyde (MDA) levels and changes in the RAPD band profile, respectively. UV stress also impaired IL6/JAK2/STAT3 signalling and activated the inflammatory mediators IL6 and TNF-α in HaCaT cells, leading to significant induction of apoptotic cell death. We found that SI-WmiR transfection prevents lipid peroxidation and oxidative stress-related DNA damage by increasing antioxidant (CuZn-SOD, Mn-SOD) and DNA repair (EXO1, SMUG1 and XRCC3) gene expression. In addition, SI-WmiRs regulated IL6/JAK2/STAT3 signalling by reducing JAK2 and STAT3 gene expression and phosphorylated protein levels compared to the control treatments. Moreover, SI-WmiRs inhibited pro-apoptotic BAX, Caspase 3 and Caspase 8 gene expression and protein levels to prevent apoptosis of UV-stressed HaCaT cells. Our results demonstrate that stress-induced wheat miRNAs produced using a biofactory approach have strong potential as a novel and effective alternative therapy for UV stress-related skin damage.

NMN recruits GSH to enhance GPX4-mediated ferroptosis defense in UV irradiation induced skin injury.

Oxidative stress and lipid peroxidation are major causes of skin injury induced by ultraviolet (UV) irradiation. Ferroptosis is a form of regulated necrosis driven by iron-dependent peroxidation of phospholipids and contributes to kinds of tissue injuries. However, it remains unclear whether the accumulation of lipid peroxides in UV irradiation-induced skin injury could lead to ferroptosis. We generated UV irradiation-induced skin injury mice model to examine the accumulation of the lipid peroxides and iron. Lipid peroxides 4-HNE, the oxidative enzyme COX2, the oxidative DNA damage biomarker 8-OHdG, and the iron level were increased in UV irradiation-induced skin. The accumulation of iron and lipid peroxidation was also observed in UVB-irradiated epidermal keratinocytes without actual ongoing ferroptotic cell death. Ferroptosis was triggered in UV-irradiated keratinocytes stimulated with ferric ammonium citrate (FAC) to mimic the iron overload. Although GPX4 protected UVB-injured keratinocytes against ferroptotic cell death resulted from dysregulation of iron metabolism and the subsequent increase of lipid ROS, keratinocytes enduring constant UVB treatment were markedly sensitized to ferroptosis. Nicotinamide mononucleotide (NMN) which is a direct and potent NAD+ precursor supplement, rescued the imbalanced NAD+/NADH ratio, recruited the production of GSH and promoted resistance to lipid peroxidation in a GPX4-dependent manner. Taken together, our data suggest that NMN recruits GSH to enhance GPX4-mediated ferroptosis defense in UV irradiation-induced skin injury and inhibits oxidative skin damage. NMN or ferroptosis inhibitor might become promising therapeutic approaches for treating oxidative stress-induced skin diseases or disorders.

Protective effect of oligosaccharides isolated from Panax ginseng C. A. Meyer against UVB-induced skin barrier damage in BALB/c hairless mice and human keratinocytes.

ETHNOPHARMACOLOGICAL RELEVANCE: Skin barrier dysfunction can lead to water and electrolyte loss, triggering homeostatic imbalances that can trigger atopic dermatitis and anaphylaxis. Panax ginseng C.A. Meyer is a traditional Chinese medicinal herb with known therapeutic benefits for the treatment of skin diseases, including photodamage repair effects and reduction of pigmentation. However, few reports exist that describe effectiveness of ginseng active components for repair of skin barrier damage. MATERIALS AND METHODS: Ginseng oligosaccharide extract (GSO) was prepared from P. ginseng via water extraction followed by ethanol precipitation and resin and gel purification. GSO composition and structural characteristics were determined using LC-MS, HPLC, FT-IR, and NMR. To evaluate GSO as a skin barrier repair-promoting treatment, skin of UVB-irradiated BALB/c hairless mice was treated with or without GSO then skin samples were evaluated for epidermal thickness, transepidermal water loss (TEWL), and stratum corneum water content. In addition, UVB-exposed skin samples and HaCaT cells were analyzed to assess GSO treatment effects on levels of epidermal cornified envelope (CE) protein and other skin barrier proteins, such as filaggrin (FLG), involucrin (IVL), and aquaporin-3 (AQP3). Meanwhile, GSO treatment was also evaluated for effects on UVB-irradiated hairless mouse skin and HaCaT cells based on levels of serine protease inhibitor Kazal type-5 (SPINK5), trypsin-like kallikrein-related peptidase 5 (KLK5), chymotrypsin-like KLK7, and desmoglein 1 (DSG1). These proteins are associated with UVB-induced skin barrier damage manifesting as dryness and desquamation. RESULTS: GSO was shown to consist of oligosaccharides comprised of seven distinct types of monosaccharides with molecular weights of approximately 1 kDa that were covalently linked together via ß-glycosidic bonds. In vivo, GSO applied to dorsal skin of BALB/c hairless mice attenuated UVB-induced epidermal thickening and moisture loss. Furthermore, GSO ameliorated UVB-induced reductions of levels of FLG, IVL, and AQP3 proteins. Additionally, GSO treatment led to increased DSG1 protein levels due to decreased expression of KLK7. In vitro, GSO treatment of UVB-irradiated HaCaT cells led to increases of FLG, IVL, and AQP3 mRNA levels and corresponding proteins, while mRNA levels of desquamation-related proteins SPINK5, KLK5, KLK7, and DSG1 and associated protein levels were restored to normal levels. CONCLUSION: A P. ginseng oligosaccharide preparation repaired UVB-induced skin barrier damage by alleviating skin dryness and desquamation symptoms, highlighting its potential as a natural cosmetic additive that can promote skin barrier repair after UVB exposure.

Disease-Dependent Antiapoptotic Effects of Cannabidiol for Keratinocytes Observed upon UV Irradiation.

Although apoptosis of keratinocytes has been relatively well studied, there is a lack of information comparing potentially proapoptotic treatments for healthy and diseased skin cells. Psoriasis is a chronic autoimmune-mediated skin disease manifested by patches of hyperproliferative keratinocytes that do not undergo apoptosis. UVB phototherapy is commonly used to treat psoriasis, although this has undesirable side effects, and is often combined with anti-inflammatory compounds. The aim of this study was to analyze if cannabidiol (CBD), a phytocannabinoid that has anti-inflammatory and antioxidant properties, may modify the proapoptotic effects of UVB irradiation in vitro by influencing apoptotic signaling pathways in donor psoriatic and healthy human keratinocytes obtained from the skin of five volunteers in each group. While CBD alone did not have any major effects on keratinocytes, the UVB treatment activated the extrinsic apoptotic pathway, with enhanced caspase 8 expression in both healthy and psoriatic keratinocytes. However, endoplasmic reticulum (ER) stress, characterized by increased expression of caspase 2, was observed in psoriatic cells after UVB irradiation. Furthermore, decreased p-AKT expression combined with increased 15-d-PGJ2 level and p-p38 expression was observed in psoriatic keratinocytes, which may promote both apoptosis and necrosis. Application of CBD partially attenuated these effects of UVB irradiation both in healthy and psoriatic keratinocytes, reducing the levels of 15-d-PGJ2, p-p38 and caspase 8 while increasing Bcl2 expression. However, CBD increased p-AKT only in UVB-treated healthy cells. Therefore, the reduction of apoptotic signaling pathways by CBD, observed mainly in healthy keratinocytes, suggests the need for further research into the possible beneficial effects of CBD.

UVB protective effects of Sargassum horneri through the regulation of Nrf2 mediated antioxidant mechanism.

The present study aimed to evaluate the protective effect of a methanol extract of Sargassum horneri (SHM), which contains 6-hydroxy-4,4,7a-trimethyl-5,6,7,7a-tetrahydrobenzofuran-2(4H)-one (HTT) and apo-9'-fucoxanthinone, against ultraviolet B (UVB)-induced cellular damage in human keratinocytes and its underlying mechanism. SHM significantly improved cell viability of UVB-exposed human keratinocytes by reducing the generation of intracellular reactive oxygen species (ROS). Moreover, SHM inhibited UVB exposure-induced apoptosis by reducing the formation of apoptotic bodies and the populations of the sub-G1 hypodiploid cells and the early apoptotic cells by modulating the expression of the anti- and pro-apoptotic molecules, Bcl-2 and Bax, respectively. Furthermore, SHM inhibited NF-κB p65 activation by inducing the activation of Nrf2/HO-1 signaling. The cytoprotective and antiapoptotic activities of SHM are abolished by the inhibition of HO-1 signaling. In further study, SHM restored the skin dryness and skin barrier disruption in UVB-exposed human keratinocytes. Based to these results, our study suggests that SHM protects the cells against UVB-induced cellular damages through the Nrf2/HO-1/NF-κB p65 signaling pathway and may be potentially useful for the prevention of UVB-induced skin damage.

Counteracting the Ramifications of UVB Irradiation and Photoaging with Swietenia macrophylla King Seed.

In this day and age, the expectation of cosmetic products to effectively slow down skin photoaging is constantly increasing. However, the detrimental effects of UVB on the skin are not easy to tackle as UVB dysregulates a wide range of molecular changes on the cellular level. In our research, irradiated keratinocyte cells not only experienced a compromise in their redox system, but processes from RNA translation to protein synthesis and folding were also affected. Aside from this, proteins involved in various other processes like DNA repair and maintenance, glycolysis, cell growth, proliferation, and migration were affected while the cells approached imminent cell death. Additionally, the collagen degradation pathway was also activated by UVB irradiation through the upregulation of inflammatory and collagen degrading markers. Nevertheless, with the treatment of Swietenia macrophylla (S. macrophylla) seed extract and fractions, the dysregulation of many genes and proteins by UVB was reversed. The reversal effects were particularly promising with the S. macrophylla hexane fraction (SMHF) and S. macrophylla ethyl acetate fraction (SMEAF). SMHF was able to oppose the detrimental effects of UVB in several different processes such as the redox system, DNA repair and maintenance, RNA transcription to translation, protein maintenance and synthesis, cell growth, migration and proliferation, and cell glycolysis, while SMEAF successfully suppressed markers related to skin inflammation, collagen degradation, and cell apoptosis. Thus, in summary, our research not only provided a deeper insight into the molecular changes within irradiated keratinocytes, but also serves as a model platform for future cosmetic research to build upon. Subsequently, both SMHF and SMEAF also displayed potential photoprotective properties that warrant further fractionation and in vivo clinical trials to investigate and obtain potential novel bioactive compounds against photoaging.

Thymoquinone, extract from Nigella sativa seeds, protects human skin keratinocytes against UVA-irradiated oxidative stress, inflammation and mitochondrial dysfunction.

Ultraviolet A (UVA) irradiation caused skin keratinocytes to accumulate reactive oxygen species (ROS) leading to the skin injury. Thymoquinone (TQ) was identified as the prominent bioactive ingredient in Nigella sativa seeds which was applied in therapying various human diseases. This study aimed to illustrate the role and mechanism of TQ in UVA-induced skin injury. We pre-treated HaCaT cells with TQ and irradiated them by UVA. MTT and Elisa assays were used to evaluate cell viability and apoptosis, as well as cytokine levels. To detect the related parameters of oxidative stress and mitochondrial function, colorimetry, spectrophotometry, bioluminescence, and dual-luciferase reporter methods were used. RT-qPCR and western blotting were performed for expressions of related mRNAs and proteins. TQ significantly improved the UVA-induced cytotoxicity on HaCaT cells. TQ treatment alleviated the oxidative stress and inflammation in UVA-irradiated keratinocytes. Besides, UVA irradiation promoted mitochondrial dysregulation in HaCaT cells leading to cell apoptosis, which could be reversed by TQ treatment. More importantly, NrF2/ARE pathway was activated in TQ-treated cells, while COX-2 was depressed, and inhibiting the pathway or activating COX-2 blocked the therapeutic effect of TQ on UVA-induced skin cell injury. Our study suggested that TQ treatment attenuated the UVA-induced oxidative and inflammatory responses, as well as mitochondrial apoptosis in keratinocytes by COX-2 inhibition via activating NrF2/ARE pathway. This might be a novel sight for preventing the solar radiation damage to the skin.

Possible treatment for UVB-induced skin injury: Anti-inflammatory and cytoprotective role of metformin in UVB-irradiated keratinocytes.

BACKGROUND: Excessive inflammation and cell death induced by ultraviolet (UV) cause skin photodamage. Metformin possesses anti-inflammatory and cytoprotective effects. However, whether metformin inhibits inflammation and cell death in UVB-induced acute skin damage is unclear. OBJECTIVE: To evaluate the anti-inflammatory and cytoprotective effects of metformin in vitro and in vivo. Furthermore, its potential mechanism has been explored. METHODS: Transcriptome sequencing and multiplex cytokines analysis were used to evaluate the validity of in vitro UVB-induced acute damage keratinocyte model and anti-inflammatory effects of metformin. We also determined the expression and nuclear translocation of CCAAT/enhancer-binding protein beta (C/EBPß), an important transcriptional factor of Interleukin-1beta (IL-1ß). Cell viability and cell death of keratinocytes were evaluated upon UVB irradiation in the presence or absence of metformin. 0.6% metformin cream was applied on UVB-irradiated mice to explore its pharmacological effects in vivo. RESULTS: Transcriptional landscape of 50 mJ/cm2 UVB-irradiated HaCaT cells is typical of UVB-induced acute damage keratinocyte model in vitro. Metformin alleviated transcription and secretion of IL-1ß, Tumor Necrosis Factor-alpha, and Fibroblast Growth Factor 2, expression and nuclear translocation of C/EBPß in this model. Metformin also protected keratinocytes from cell death caused by UVB-induced cellular secretions, which contributed to its cytoprotective effects. Topical administration of 0.6% metformin cream alleviated UVB-induced skin damage in mice. CONCLUSION: We proved the protective roles of metformin in UVB-challenged keratinocytes and UVB-irradiated mice, which indicated the potential value of metformin in topical therapy against skin photodamage.

The Effect of Cannabidiol on UV-Induced Changes in Intracellular Signaling of 3D-Cultured Skin Keratinocytes.

Human epidermal keratinocytes are constantly exposed to UV radiation. As a result, there is a significant need for safe and effective compounds to protect skin cells against this environmental damage. This study aimed to analyze the effect of phytocannabinoid-cannabinoid (CBD)-on the proteome of UVA/B irradiated keratinocytes. The keratinocytes were cultured in a three-dimensional (3D) system, designed to mimic epidermal conditions closely. The obtained results indicate that CBD protected against the harmful effects of UVA/B radiation. CBD decreased the expression of proinflammatory proteins, including TNFα/NFκB and IκBKB complex and decreased the expression of proteins involved in de novo protein biosynthesis, which are increased in UVA/B-irradiated cells. Additionally, CBD enhanced the UV-induced expression of 20S proteasome subunits. CBD also protected protein structures from 4-hydroxynonenal (HNE)-binding induced by UV radiation, which primarily affects antioxidant enzymes. CBD-through its antioxidant/anti-inflammatory activity and regulation of protein biosynthesis and degradation-protects skin cells against UVA/B-induced changes. In the future, its long-term use in epidermal cells should be investigated.

Purified Cannabidiol isolate does not inhibit active caspase-1 release in NLRP inflammasome-mediated UVB or ATP-activated keratinocytes or appear to reduce key inflammatory cytokines in UVB-irradiate keratinocytes.

BACKGROUND: Cannabidiol is a plant-derived cannabinoid that has been suggested to have several human health benefits including potential anti-inflammatory effects. It is now common to find various forms of Cannabidiol, most often referred to as CBD, in nutritional supplements and topical treatments. The mechanisms by which CBD can influence inflammatory pathways in the body, and more particularly in the skin, are presently still unclear. It is known that CBD will bind to cannabinoid receptors, CB1 and CB2, in the body and recent work has shown that in keratinocytes, CBD can regulate inflammation through transcriptional regulation involving the NFÆ™ß nuclear pathways. The fact that CBD operates through the NFÆ™ß pathways suggests that, perhaps, the molecule may influence the expression of active caspase-1 through NLRP inflammasome-mediated pathways. METHODS: Recently, work has published demonstrating that Normal Human Epidermal Keratinocytes (NHEKs) can be activated by UVB and ATP to express active caspase-1 via NLRP inflammasome-mediated pathways. There was a strong interest to see whether highly purified Cannabidiol Isolate (>99% purity) might function to control release of active caspase-1 by testing of NHEKs using the previously described models. In addition, NHEKs expression of non-NLRP inflammasome-induced inflammation markers including IL-6, IL-8 and PGE2 was examined in UVB-activated NHEKs. RESULTS: It was found that purified Cannabidiol Isolate did not influence active caspase-1 release in either UVB or ATP-activated NHEKs suggesting the molecule does not influence the NLRP inflammasome pathways. In addition, it was surprisingly found that the Cannabidiol Isolate did not impact the expression of additional UVB-activated non-NLRP inflammatory markers. CONCLUSIONS: Data presented suggest that if Cannabidiol functions as an anti-inflammatory, it does so through pathways not associated with either the NLRP inflammasome-mediated expression of caspase-1 or through the more commonly known expression of interleukin or prostaglandin inflammatory pathways.

CONTEXTE: Le cannabidiol est un cannabinoïde d'origine végétale considéré comme bénéfique pour la santé humaine et présentant notamment des effets anti-inflammatoires potentiels. Il est désormais courant de trouver diverses formes de cannabidiol dans les suppléments alimentaires et les traitements topiques. Les mécanismes par lesquels le cannabidiol peut influencer les voies inflammatoires dans l'organisme, et plus particulièrement dans la peau sont actuellement encore flous. On sait que le cannabidiol se lie aux récepteurs cannabinoïdes, CB1 et CB2 dans l'organisme et des travaux récents ont montré que dans les kératinocytes, le cannabidiol peut réguler l'inflammation par régulation transcriptionnelle impliquant les voies nucléaires NF-ƙß. Le fait que le cannabidiol fonctionne par le biais des voies NF-Æ™ß laisse à penser que la molécule peut influencer l'expression de la Caspase-1 active à travers les voies médiées par l'inflammasome NLRP. MÉTHODES: Récemment, des travaux ont été publiés démontrant que les kératinocytes épidermiques humains normaux (Normal Human Epidermal Keratinocytes, NHEK) peuvent être activés par les UVB et l'ATP pour exprimer la Caspase-1 active à travers les voies médiées par l'inflammasome NLRP. On cherchait surtout à savoir si l'isolat de cannabidiol hautement purifié (pureté > 99 %) pouvait fonctionner pour contrôler la libération de Caspase-1 active en analysant les NHEK à l'aide des modèles décrits précédemment. En outre, l'expression des NHEK des marqueurs de l'inflammation induits par l'inflammasome non-NLRP, notamment : IL-6, IL-8 et la PGE2 ont été examinées dans des NHEK activées par les UVB. RÉSULTATS: Il a été constaté que l'isolat de cannabidiol purifié n'influençait pas la libération active de Caspase-1 dans les NHEK activées par les UVB ou l'ATP, ce qui suggère que la molécule n'influence pas les voies de l'inflammasome NLRP. En outre, il a été surprenant de constater que l'isolat de cannabidiol n'avait pas d'impact sur l'expression des marqueurs inflammatoires non-NLRP activés par les UVB supplémentaires. CONCLUSIONS: Les données présentées suggèrent que si le cannabidiol fonctionne comme un anti-inflammatoire, il le fait par des voies non associées à l'expression de la Caspase-1 médiée par l'inflammasome NLRP ou par l'expression plus connue des voies inflammatoires de l'interleukine ou de la prostaglandine.

Role of Hypotaurine in Protection against UVA-Induced Damage in Keratinocytes.

Photoageing and skin cancer are major causes of morbidity and are a high cost to society. Interest in the development of photoprotective agents for inclusion in topical cosmetic and sunscreen products is profound. Recently, amino acids with a sulfinic group, notably hypotaurine, have been included as ingredients in cosmetic preparations. However, the mechanism of action of hypotaurine as a possible anti-aging agent is unknown, despite its use as a free radical scavenger. To address this issue, we investigated hypotaurine uptake in a human keratinocyte model and examined its effect on UVR-induced cytotoxicity. Hypotaurine was taken up by keratinocytes in a time- and concentration-dependent manner, with levels remaining significantly above baseline 48 h after washout. A cytoprotective effect of pre-incubation with 2.5-5 mMhypotaurine was shown as indicated by increased cell viability when keratinocytes were irradiated with UVA at 5 or 10 Jcm-2 , with the level of hypotaurine also significantly reduced. These findings indicate a potential cytoprotective effect of hypotaurine against the deleterious effects of UVA irradiation. This provides support for further studies to evaluate the potential photoprotective benefits of hypotaurine supplementation of topical cosmetic and sunscreen products.

Uranium directly interacts with the DNA repair protein poly (ADP-ribose) polymerase 1.

People living in southwest part of United States are exposed to uranium (U) through drinking water, air, and soil. U is radioactive, but independent of this radioactivity also has important toxicological considerations as an environmental metal. At environmentally relevant concentrations, U is both mutagenic and carcinogenic. Emerging evidence shows that U inhibits DNA repair activity, but how U interacts with DNA repair proteins is still largely unknown. Herein, we report that U directly interacts with the DNA repair protein, Protein Poly (ADP-ribose) Polymerase 1 (PARP-1) through direct binding with the zinc finger motif, resulting in zinc release from zinc finger and DNA binding activity loss of the protein. At the peptide level, instead of direct competition with zinc ion in the zinc finger motif, U does not show thermodynamic advantages over zinc. Furthermore, zinc pre-occupied PARP-1 zinc finger is insensitive to U treatment, but U bound to PARP-1 zinc finger can be partially replaced by zinc. These results provide mechanistic basis on molecular level to U inhibition of DNA repair.

Biomimetic Alginate/Gelatin Cross-Linked Hydrogels Supplemented with Polyphosphate for Wound Healing Applications.

In the present study, the fabrication of a biomimetic wound dressing that mimics the extracellular matrix, consisting of a hydrogel matrix composed of non-oxidized and periodate-oxidized marine alginate, was prepared to which gelatin was bound via Schiff base formation. Into this alginate/oxidized-alginate-gelatin hydrogel, polyP was stably but reversibly integrated by ionic cross-linking with Zn2+ ions. Thereby, a soft hybrid material is obtained, consisting of a more rigid alginate scaffold and porous structures formed by the oxidized-alginate-gelatin hydrogel with ionically cross-linked polyP. Two forms of the Zn-polyP-containing matrices were obtained based on the property of polyP to form, at neutral pH, a coacervate-the physiologically active form of the polymer. At alkaline conditions (pH 10), it will form nanoparticles, acting as a depot that is converted at pH 7 into the coacervate phase. Both polyP-containing hydrogels were biologically active and significantly enhanced cell growth/viability and attachment/spreading of human epidermal keratinocytes compared to control hydrogels without any adverse effect on reconstructed human epidermis samples in an in vitro skin irritation test system. From these data, we conclude that polyP-containing alginate/oxidized-alginate-gelatin hydrogels may provide a suitable regeneratively active matrix for wound healing for potential in vivo applications.

Cannabidiol-Mediated Changes to the Phospholipid Profile of UVB-Irradiated Keratinocytes from Psoriatic Patients.

UVB phototherapy is treatment for psoriasis, which increases phospholipid oxidative modifications in the cell membrane of the skin. Therefore, we carried out lipidomic analysis on the keratinocytes of healthy individuals and patients with psoriasis irradiated with UVB and treated with cannabidiol (CBD), phytocannabinoid with antioxidant and anti-inflammatory properties. Our results showed that, in psoriatic keratinocytes phosphatidylcholine (PC), phosphatidylinositol (PI), phosphatidylserine (PS), and ether-linked phosphoethanolamine (PEo), were downregulated, while SM (d41:2) was upregulated. These changes were accompanied by an increase in negative zeta potential, which indicates translocation of PS to the outer layer of the membrane. CBD treatment of psoriatic keratinocytes led to downregulation of PC, PS, and upregulation of certain PEo and an SM species, SM (d42:2), and the zeta potential. However, UVB irradiation of psoriatic keratinocytes resulted in upregulation of PC, PC plasmalogens (PCp), PEo, and a decrease in the negative zeta potential. The exposure of UVB-irradiated cells to CBD led to a decrease in the level of SM (d42:2). Our results suggest that CBD induces pro-apoptotic mechanisms in psoriatic keratinocytes while simultaneously improving the antioxidant properties and preventing the loss of transepidermal water of keratinocytes of patients irradiated with UVB. Thus, CBD has potential therapeutic value in the treatment of psoriasis.

Protective effects of Sosihotang extract against ultraviolet B-induced skin photoageing in hairless mice.

OBJECTIVES: Sosihotang (SSH) is an herbal medicine traditionally used against the common cold, and hepatic and gastric diseases, in Northeast Asia. In this study, we investigated whether SSH extract can protect against UVB-induced skin damage and photoageing. METHODS: HaCaT cells were treated with SSH extract and exposed UVB irradiation at 20 mJ/cm2 . Hairless mice were orally administered SSH extract (100 mg/kg per mouse) as UVB irradiation was increased from 60 to 120 mJ/cm2 over the course of 12 weeks. KEY FINDINGS: Treatment with SSH extract inhibited the upregulation of MMP-1 and MMP-9 expression in UVB-irradiated HaCaT cells. In UVB-irradiated hairless mice, treatment with SSH extract restored the levels of factors instrumental in skin hydration (TEWL, capacitance, HA and TGF-ß) and those regulating collagen content (procollagen, MMP-1 and MMP-9). This activity inhibited epidermal thickening and disorganization of collagen fibres. Administration of SSH extract also ameliorated the expression of UVB-induced pro-inflammatory cytokines (TNF-α, IL-1ß and IL-6) and phosphorylation of MAPK family members (MEK, JNK, ERK and p38) by upregulating the activity of antioxidant enzymes (SOD, CAT, Nrf-2, HO-1 and NQO-1). CONCLUSIONS: These results indicate that SSH extract can be used therapeutically for the treatment of UVB-induced skin damage and photoageing.

Step gradient alcohol precipitation for the purification of low molecular weight fucoidan from Sargassum siliquastrum and its UVB protective effects.

Ultraviolet B (UVB) can induce oxidative damage to outermost layers of skin causing suntans, sunburns, and, in severe cases, blisters leading to photoaging. Low molecular weight (MW) fucoidan is renowned for possessing enhanced antioxidant activities. The present study discloses the use of step gradient ethanol precipitation in refining fucoidan fractions (SSQC1-SSQC4) from Sargassum siliquastrum and evaluation of their UVB-protective effects in human HaCaT keratinocytes. Among the fractions, SSQC4 indicated the best bioactive effects. 1H NMR, FTIR, monosaccharide composition by HPAEC-PAD analysis, MW estimation by agarose gel electrophoresis were used to characterize the fractions. SSQC4 was comprising of fucoidan, with an estimated MW distribution of 8-25 kDa. Exposure of UVB increased intracellular ROS, DNA damage, loss of mitochondrial membrane potential, apoptotic body formation causing cell death through the mitochondria-mediated apoptosis pathway. SSQC4 treatment could dose-dependently attenuate the ROS levels and suppress mitochondria-mediated apoptosis in UVB exposed keratinocytes. SSQC4 treatment enhanced cellular antioxidant defense by increasing Nrf2 mediated HO-1 generation, which was identified as the cause of observed bioactivities. The safety and stability of SSQC4 could be further evaluated to promote its use as a bioactive natural ingredient in UV-protective cosmetics.

ER stress induced by ER calcium depletion and UVB irradiation regulates tight junction barrier integrity in human keratinocytes.

BACKGROUND: Endoplasmic reticulum (ER) calcium depletion-induced ER stress is a crucial signal for keratinocyte differentiation and barrier homeostasis, but its effects on the epidermal tight junction (TJ) have not been characterized. Ultraviolet B (UVB) causes ER calcium release in keratinocytes and disrupts epidermal TJ, however, the involvement of ER stress in the UVB-induced TJ alterations remains unknown. OBJECTIVES: To investigate the effect of ER stress by pharmacological ER calcium depletion or UVB on the TJ integrity in normal human epidermal keratinocytes (NHEK). METHODS: NHEK were exposed to ER calcium pump inhibitor thapsigargin (Tg) or UVB. ER stress markers and TJ molecules expression, TJ and F-actin structures, and TJ barrier function were analyzed. RESULTS: Tg or UVB exposure dose-dependently triggered unfolded protein response (UPR) in NHEK. Low dose Tg induced the IRE1α-XBP1 pathway and strengthened TJ barrier. Contrary, high dose Tg activated PERK phosphorylation and disrupted TJ by F-actin disorganization. UVB disrupted TJ and F-actin structures dose dependently. IRE1α RNase inhibition induced or exacerbated TJ and F-actin disruption in the presence of low dose Tg or UVB. High dose Tg increased RhoA activity. 4-PBA or Rho kinase (ROCK) inhibitor partially prevented the disruption of TJ and F-actin following high dose Tg or UVB. CONCLUSIONS: ER stress has bimodal effects on the epidermal TJ depending on its intensity. The IRE1α pathway is critical for the maintenance of TJ integrity during mild ER stress. Severe ER stress-induced UPR or ROCK signalling mediates the disruption of TJ through cytoskeletal disorganization during severe ER stress.