The UV response of the skin: a review of the MAPK, NFkappaB and TNFalpha signal transduction pathways

Lysine-Proline-Valine peptide mitigates fine dust-induced keratinocyte apoptosis and inflammation by regulating oxidative stress and modulating the MAPK/NF-κB pathway

Airborne particulate matter (PM) poses a major environmental risk that impairs skin health by triggering oxidative stress, inflammation, and cell death. In this study, we investigated the protective effects of Lysine-Proline-Valine (KPV)-an endogenous peptide derived from α-melanocyte-stimulating hormone-against oxidative damage and inflammation induced by fine PM (PM10) in human HaCaT keratinocytes. Our results show that PM10 markedly suppresses HaCaT cell proliferation via cytotoxic effects and induces a pro-inflammatory response by increasing IL-1β secretion. Notably, treatment with 50 μg/mL of KPV restored cell viability and reduced IL-1β secretion disrupted by PM10 exposure. To counteract PM10-induced cell death, KPV inhibited reactive oxygen species (ROS) production, which is responsible for activating extracellular signal-regulated kinase and p38 mitogen-activated protein kinase. Additionally, KPV decreased the expression of apoptosis-related proteins (Bax, Bcl-2, and cleaved caspase-3) and IL-1β through suppression of the redox-sensitive transcription factor nuclear, factor-kappa B in PM10-treated HaCaT cells. Against PM10-induced inflammation, KPV effectively blocked ROS-mediated caspase-1 activation, reducing IL-1β secretion. In a three-dimensional (3D) skin model, KPV treatment effectively attenuated the inflammatory cell death induced by PM10. Collectively, these findings suggest that KPV protects keratinocytes by mitigating PM10-induced pyroptosis and holds potential as a therapeutic agent for preventing environmental pollutant-related skin damage, with promising applications in functional cosmetics and skin-protective treatments.

Assessing phototoxic drug properties of hydrochlorothiazide using human skin biopsies

The diuretic drug hydrochlorothiazide (HCT) is associated with an increased risk of non-melanoma skin cancer upon UV exposure. The underlying cellular and molecular mechanisms behind this association remain elusive. Herein, a human skin model to assess the photocarcinogenic effects of HCT is established. Skin biopsies collected from human body donors are treated with HCT and irradiated with 300 mJ/cm2 low dose UVA or UVB or with 5 J/cm2 high dose UVA. In HCT-treated biopsies but not in control, low dose UVA irradiation results in activation and nuclear translocation of the tumor-suppressor protein p53 accompanied by an upregulated gene expression of p53-negative regulator MDM2. High dose UVA additionally provokes DNA damage and initiation of pro-inflammatory gene expression. In contrast, UVB induces pronounced DNA damage, p53 protein activation, gene expression of MDM2 and inflammatory marker genes in both HCT-treated biopsies and untreated control. In summary, in HCT-treated skin biopsies, activation of the p53-MDM2 axis, induction of DNA damage, and inflammatory response depends on UVA-dosage and may influence skin carcinogenesis over time. This human model eliminates the need for animal testing and mitigates species difference, offering a valuable tool for future drug development and safety testing.

Discovery and Biosynthesis of Indole-Functionalized Metabolites from the Human Blood Bacterium, Paracoccus sanguinis, and Their Anti-Skin Aging Activity

The human microbiome plays a crucial role in health and disease, with microbial metabolites acting as key mediators of physiological processes. While extensive research has focused on gut-derived microbes, the metabolic contributions of blood-derived bacteria remain underexplored. Here, we investigate the facultative anaerobe Paracoccus sanguinis, a Gram-negative bacterium isolated from human blood, and its metabolome, revealing insights into its potential impacts on health and disease. Using advanced analytical methods, we characterized 12 metabolites (1-12), including six novel compounds (1-3, 9, 10, and 12). Biosynthetic studies demonstrated that these metabolites are derived through enzymatic and nonenzymatic pathways. Functional evaluations revealed significant antiaging activities for 1, 6, and 11 in TNF-α-stimulated normal human dermal fibroblasts (NHDFs), including suppression of reactive oxygen species (ROS), inhibition of matrix metalloproteinase-1 (MMP-1) secretion, and reduction of inflammatory cytokines interleukin (IL)-6 and IL-8. Among the tested compounds, 11 exhibited the highest antiaging efficacy, highlighting its potential as a candidate for therapeutic applications targeting skin aging. This study elucidates the biosynthetic pathways of P. sanguinis metabolites and their antiskin aging activity, underscoring their potential in modulating skin health and offering novel insights into the functional roles of blood-derived microbiota in human health.

Effects of Astraflavonoid A and Astraside C from the Aerial Part of Astragalus membranaceus on TNF-α-Induced Human Dermal Fibroblasts

The present study investigates the anti-skin-aging properties and bioactive compounds of the aerial parts of Astragalus membranaceus, which are typically discarded as agricultural waste. Liquid chromatography-mass spectrometry analysis identified flavonoid glycosides as the major constituents of the aerial parts of A. membranaceus extract. Two principal flavonoids, astraflavonoid A (1) and astraside C (2), were isolated using repetitive chromatography. Compounds 1 and 2 demonstrated antioxidative properties, reducing reactive oxygen species and matrix metalloproteinase-1 levels in human dermal fibroblasts upon stimulation with TNF-α. Specifically, astraside C (2) inhibited the expression of pro-inflammatory cytokines interleukin-6 and interleukin-8, whereas astraflavonoid A (1) did not affect their expression. Additionally, the expression of inflammatory mediators such as nuclear factor kappa B and cyclooxygenase-2 (COX-2) was increased by 1, whereas it was suppressed by 2. Furthermore, in silico molecular docking experiments confirmed that compound 2 effectively binds to COX-2. These findings suggest that the aerial parts of A. membranaceus contain bioactive flavonol glycosides with promising anti-skin-aging properties, offering valuable use as agricultural byproducts.

Synergistic effects of oral milk ceramide-collagen peptides mixtures in preventing UV-induced inflammation and photoaging through TGF-β and NF-κB/MAPK signaling pathways in UV-exposed hairless mice

This study investigates the synergistic effects of oral milk ceramide-collagen peptides in inhibiting UV-induced inflammation and preventing photoaging. The optimal ratio of milk ceramide to collagen peptides was determined in HaCaT cells, and the effects of oral supplementation of milk ceramide-collagen peptides were evaluated in UV-exposed hairless mice. HaCaT cells did not exhibit cytotoxicity when treated with milk ceramide and collagen peptides at concentrations up to 200 μg/mL. UVB exposure decreased cell viability, but treatment with the milk ceramide-collagen peptides mixtures (1:1, 1:3) prevented further viability loss and improved collagen peptides synthesis markers, including MMPs and TIMPs. The combination also enhanced moisture-related factors (AQP3, FLG) and reduced inflammatory cytokines (IL-6, IL-1β) and COX expression. In hairless mice, oral supplementation of milk ceramide-collagen peptides mixture (1:1 ratio) improved skin hydration, reduced erythema, TEWL, skin thickness, and wrinkle formation in a dose-dependent manner. The treatment also suppressed the expression of MMPs and TIMPs, promoting collagen peptides synthesis. Furthermore, the mixtures regulated NF-κB and MAPK signaling pathways, reducing inflammation and photoaging. These results suggest that the 1:1 milk ceramide-collagen peptides mixture effectively prevents UV-induced skin damage and photoaging by enhancing collagen peptides production and improving skin barrier function.

Myricetin alleviates the mechanism of IL-1β production caused by the endocrine-disrupting chemical Di(2-ethylhexyl) phthalate in RAW 264.7 cells

Myricetin, a flavonoid present in numerous fruits, vegetables, and medicinal plants, is recognized for its potent antioxidant, anti-inflammatory, and anti-cancer activities. Nevertheless, its involvement in mitigating inflammation caused by the endocrine-disrupting chemical Di(2-ethylhexyl) phthalate (DEHP), commonly used in polyvinyl chloride (PVC) manufacturing to improve flexibility, has not been investigated. Here, we found that DEHP markedly increased IL-1β production through inflammatory pathways in RAW 264.7 murine macrophages. Treatment with myricetin at a concentration of 10 μM significantly reduced the elevated IL-1β levels. Myricetin achieves this by inhibiting the activation of protein kinase C (PKC) and extracellular signal-regulated kinase (ERK), which are driven by reactive oxygen species (ROS), thereby suppressing IL-1β transcription via nuclear factor-kappa B (NF-κB). Additionally, myricetin prevents ROS-induced activation of the NLRP3 inflammasome and subsequent caspase-1 activation, further decreasing IL-1β production. These dual actions highlight myricetin's therapeutic potential in countering the oxidative stress-mediated inflammatory pathways triggered by environmental toxins like DEHP.

Evaluation of the Antiaging Potential of the Dendropanax morbiferus-Derived Compound Dendropanoxide in TNF-α-Stimulated Human Dermal Fibroblasts

In this study, we investigated the antiaging potential of dendropanoxide (DP), an active compound derived from Dendropanax morbiferus, in human dermal fibroblasts (NHDFs) induced by Tumor Necrosis Factor-alpha (TNF-α) and in human epidermal keratinocytes (NHEKs) induced by TNF-α and interferon gamma (IFN-γ). We induced oxidative stress related to ultraviolet (UV) radiation with TNF-α and IFN-γ and then treated the cells with various concentrations of DP to evaluate its effects on reactive oxygen species (ROS) production, matrix metalloproteinase-1 (MMP-1) expression, collagen synthesis, inflammatory cytokine expression, and skin barrier protection. The results showed that DP significantly reduced ROS production, indicating its potential to alleviate oxidative stress in the skin. Additionally, DP effectively inhibited MMP-1 production, suggesting that it could prevent collagen degradation in the dermis, significantly increase the secretion of pro-collagen I, promote collagen synthesis, and protect the dermal extracellular matrix (ECM). Moreover, DP significantly reduced the expression of inflammatory cytokines IL-1β and IL-6, thereby inhibiting excessive inflammatory responses in the skin. DP also enhanced the gene expression of key factors involved in skin barrier maintenance, including Kazal-type 5 (SPINK5), loricrin (LOR), aquaporin-3 (AQP3), filaggrin (FLG), and keratin 1 (KRT1), suggesting its potential to maintain and protect the skin barrier. Western blot analysis revealed that DP inhibited TNF-α-induced phosphorylation of JNK and p38, implying that DP exerts antiaging effects through the regulation of the JNK and p38 signaling pathways. Collectively, these findings suggest that DP has significant potential as an antiaging agent.

Comprehensive genome-wide identification and functional characterization of mapk gene family in northern snakeheads (Channa argus)

The mitogen-activated protein kinase (MAPK) signaling cascade, integral to cellular regulation, orchestrates cell growth, differentiation, stress response, and inflammatory reactions to adapt to challenging environments. The northern snakeheads (Channa argus), a valuable freshwater species known for its hypoxia tolerance, rapid growth, and high nutritional value, lacks comprehensive research on its mapk gene family. In this study, we identified 16 mapk genes in northern snakeheads, among which mapk8, mapk12 and mapk14 have duplicate copies. Phylogenetic analysis confirmed the evolutionary conservation of this gene family. Structural and motif analyses further underscored the conserved nature of these genes. Expression pattern analysis under abiotic and biotic stress conditions showed significant differences expression of mapks in the gills and suprabranchial organ (SBO) after air exposure, as well as in the brain following cold stress, highlighting the extensive role of mapks in stress regulation. It was worth noting that the significant expression differences of mapks were also observed in the spleen after N. seriolae infection, implicating that these genes may be involved in the regulation of innate immune responses. Additionally, analysis of protein-protein interaction (PPI) networks suggested that the co-activation of multiple MAPK signaling pathways may play a key role in regulating an organism's response to biotic and abiotic stresses. This study provides a detailed description of the mapk gene family in the northern snakeheads and elucidates its biological functions under various stress conditions, offering valuable insights into the regulatory mechanisms of the mapk gene family.

Penilumamide, a novel SIRT1 activator, protects UVB-induced photodamages in HaCaT cells

Ultraviolet-B (UVB) radiation is a major physical factor that induces structural changes in human skin. The aim of this study was to determine whether the novel silent information regulator 1 (sirtuin 1 SIRT1) protein activator, penilumamide, exerted any protective effects against UVB-induced skin damage using human HaCaT keratinocytes as a model. Enzymatic assays were performed to determine the SIRT1-activating ability of penilumamide, which was compared with that of resveratrol, a potent natural product SIRT1 activator with antioxidant and anti-inflammatory properties. Penilumamide markedly activated SIRT1 enzyme activity compared to resveratrol. To further investigate the protective effect of penilumamide against UVB-induced cytotoxicity, HaCaT cells were pretreated with penilumamide (10 μM) for 24 hr followed by irradiation with UVB (40 mJ/cm2). UVB (40 mJ/cm2) irradiation significantly reduced cell viability in a time-dependent manner, whereas pretreatment with penilumamide blocked this effect. Further, penilumamide decreased the levels of intracellular reactive oxygen species (ROS) generated by UVB irradiation in HaCaT cells. Pretreatment with penilumamide also prevented UVB irradiation-induced changes in mitochondrial membrane potential (ΔΨm). In addition, pretreatment with penilumamide significantly reduced the expression levels of pro-inflammatory cytokines, interleukin (IL)-6, IL-8, and IL-10 and phosphorylation of nuclear factor-kB (NF-kB). These results indicate that penilumamide protects HaCaT cells from UVB-induced inflammation. Taken together data demonstrate that penilumamide exerted protective effects against UVB-induced ROS generation in HaCaT cells. Therefore, penilumamide may be considered to be used as a new SIRT1 activator to protect human keratinocyte against UVB-induced damage.

Effect of cadmium stress on gill tissues of Magallana gigas after adaptation to different light conditions

Cadmium (Cd) is a highly soluble pollutant in aquatic ecosystems that poses a significant threat to mollusks. In this study, a solar simulator with a filter was used to establish two light conditions (with and without the ultraviolet [UV] spectrum) for a light-adaptation period (120 d) in Magallana gigas. Following adaptation, Cd was introduced into seawater containing M. gigas. Comprehensive bioaccumulation, physiological, and transcriptomic analyses were conducted to assess the responses of M. gigas gill tissues to Cd exposure following adaptation to simulated light. The results demonstrated that Cd exposure under both light conditions increased activities of catalase, superoxide dismutase, and glutathione S-transferase, and altered glutathione content, indicating that Cd consistently induced oxidative stress in M. gigas gill tissues. Transmission electron microscopy analysis revealed more severe cellular structural damage and a reduction in mitochondria under Cd exposure with photosynthetically active radiation (PAR) than under UV radiation, suggesting a more pronounced stress response under PAR. This may lead to lipid peroxidation and mitochondrial dysfunction in gill tissues. Additionally, co-exposure to Cd and UV radiation upregulated genes related to carbohydrate and lipid metabolism in the gill tissue, indicating increased energy demand. This high-energy state may have reduced the stress induced by Cd in the gill tissue. These findings highlight the importance of exploring different response strategies among mollusks with varied environmental adaptabilities, while underscoring the significance of considering their environmental acclimation history when investigating the toxicological mechanisms of heavy metal exposure in marine species.

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 in vivo experiment needs to be further confirmed in future.

Evaluation of the Biological Effect of a Nicotinamide-Containing Broad-Spectrum Sunscreen on Photodamaged Skin

INTRODUCTION

UVA-UVB increases skin matrix metalloproteinases and breaks down extracellular proteins and fibrillar type 1 collagen, leading to photodamage. Topical application of nicotinamide prevents UV-induced immunosuppression. Several studies have demonstrated the importance of protection against UV. This study aims to determine the biological effect of a high broad-spectrum UVB-UVA sunscreen containing nicotinamide and panthenol (SSNP) on photodamaged skin using linear confocal optical coherence tomography (LC-OCT), immunohistochemistry, and RNA profiling.

METHODS

Two areas of severely photodamaged forearm skin (L01 and L02) and one less sun-damaged (naturally protected) area on the inner part of the forearm (L03) were identified in 14 subjects. These areas were imaged using LC-OCT and L01 and L03 were biopsied at baseline. After 4 weeks of treatment with SSNP, L02 was reimaged using LC-OCT, and biopsied. Histology, immunostaining with p21, p53, PCNA, and CPD, and RNA sequencing were performed in all samples.

RESULTS

LC-OCT analysis showed that epidermis thickness and the number of keratinocytes is higher in the sun-exposed areas than in the non-exposed areas. Comparing before and after treatment, even though there is a trend towards normalization, the differences were not statistically significant. The expression of p21, PCNA, p53, and CPD increased in severely photodamaged skin compared to less-damaged skin. When comparing before and after treatment, only p21 showed a trend to decrease expression. RNA sequencing analysis identified 1552 significant genes correlating with the progression from non-visibly photodamaged skin to post-treatment and pre-treatment samples; in the analysis comparing pre- and post-treatment samples, 5429 genes were found to be significantly associated. A total of 1115 genes are common in these two analyses. Additionally, nine significant genes from the first analysis and eight from the second are related to collagen. Six of these collagen genes are common in the two analyses. MAPK and cGMP-PKG signalling pathways are upregulated in the progression to photodamage analysis. In the pre- and post-treatment analysis, 32 pathways are downregulated after treatment, the most statistically significant being the ErbB, Hippo, NOD-like receptor, TNF, and NF-kB signalling pathways.

CONCLUSION

This study demonstrates the role of SSNP in collagen generation, highlights the relevance of the cGMP-PKG and MAPK signalling pathways in photodamage, and shows the ability of SSNP to downregulate pathways activated by UV exposure. Additionally, it deepens our understanding of the effect of SSNP on immune-related pathways.

Methylsulfonylmethane promotes melanogenesis via activation of JNK in Mel-Ab cells

OBJECTIVE

Methylsulfonylmethane (MSM), which contains organic sulphur, has been used for a long time as a medicinal ingredient because of its benefits to human health. MSM is reported to be protective against certain skin disorders, but it is unknown whether it affects melanin synthesis. Therefore, in our current research, we examined the possibility of MSM controlling the production of melanin in Mel-Ab melanocytes.

METHODS

In Mel-Ab cells, melanin contents and tyrosinase activities were assessed and quantified. The expression of microphthalmia-associated transcription factor (MITF) and tyrosinase was evaluated using western blot analysis, while MSM-induced signalling pathways were investigated.

RESULTS

The MSM treatment significantly resulted in a dose-dependent increase in melanin production. Furthermore, MSM elevated melanin-related proteins, including MITF and tyrosinase. However, the rate-limiting enzyme of melanin production, tyrosinase, was not directly influenced by it. Therefore, we investigated potential melanogenesis-related signalling pathways that may have been triggered by MSM. Our findings showed that MSM did not influence the signalling pathways associated with glycogen synthase kinase 3β, cAMP response-element binding protein, extracellular signal-regulated kinase, or p38 mitogen-activated protein kinase. However, MSM phosphorylated c-Jun N-terminal kinases/stress-activated protein kinase (JNK/SAPK), which is known to induce melanogenesis. SP600125, a specific JNK inhibitor, inhibited MSM-induced melanogenesis.

CONCLUSION

Taken together, our study indicates that MSM induces melanin synthesis and may serve as a therapeutic option for hypopigmentary skin disorders such as vitiligo.

Proteomic analysis of the combined effects of cannabigerol and 3-O-ethyl ascorbic acid on kinase-dependent signalling in UVB-irradiated human keratinocytes

Oxidative stress induced by medium-wavelength ultraviolet radiation (UVB) is one of the most dangerous environmental stressors for the skin. Therefore, various medicinal remedies aim to prevent the harmful effects of UVB or support the recovery of the damaged cells. This study aimed to evaluate the impact of bioactive phytocannabinoid cannabigerol (CBG) together with 3-O-ethyl ascorbic acid (EAA), a stable, lipophilic derivative of the antioxidant vitamin C, on UVB-induced changes of proteome in cultured human keratinocytes 24 h after treatment. Surprisingly, proteomic analysis revealed very prominent CBG and EAA effects on kinases. These changes mainly influenced ERK1/2, IKK, MAP3K7, MAPK14, RIPK2, and NLK. Their expression was decreased by CBG and EAA, especially if used together after UVB-irradiation, so the effects of UVB were abolished restoring the profile of kinases to non-irradiated control. Moreover, CBG and EAA also reduced the UVB-induced modifications of proteins by the lipid peroxidation product 4-hydroxynonenal, especially in the case of AKT, Camkk1, cJun, ERK1, IKKα, MAPK11 and PERK. We conclude that, by maintaining proteome stability and kinase-dependent signalling, both CBG and EAA may support the recovery of human keratinocytes exposed to UVB radiation, especially if applied together, while the time-dependence of these effects should be further studied.

The role of CREB and MAPK signaling pathways in ATLL patients

BACKGROUND

HTLV-1 is a worldwide distribution retrovirus with 10-20 million infected individuals. ATLL is an Adult T-cell leukaemia lymphoma caused by aggressive T-cell proliferation that is infected by HTLV-1 and is associated with an inferior prognosis. The exact molecular pathogenesis has yet to be fully understood. CREB, a transcription factor, acts as a molecular switch that controls the expression of numerous genes in response to various extracellular signals. Its activation is primarily mediated through phosphorylation by multiple kinases, including MAPKs. MAPKs, a family of serine/threonine kinases, serve as crucial mediators of intracellular signaling cascades.

METHOD AND MATERIAL

This study investigated, 38 HTLV-I-infected individuals, including 18 HTLV-1 asymptomatic carriers (ACs) and 20 ATLL subjects. mRNA was extracted and converted to cDNA from Peripheral blood mononuclear cells (PBMCs), and then the expression of TAX, HBZ, CREB, and MAPK was analyzed by TaqMan qPCR. The genomic HTLV-1 Proviral loads were examined among the study group.

RESULTS

The data analysis showed a significant difference in the mean of CREB expression amongst study groups (ATLL and carriers, (p = 0.002). There is no statistical difference between the MAPK gene expression (p = 0.35). HBZ, TAX, and HTLV-1 proviral load weree significantly higher in ATLL subjects compared to  ACs  (p = 0.002, 0.000, and 0.000), respectively. Moreover, our results, demonstrated a direct positive correlation among HBZ, CREB, and TAX gene expression in ATLL patients (p = 0.001), whilst between the  ACs, TAX gene expression had a positive significant correlation with HBZ and HTLV-1 proviral load (p = 0.007 and p = 0.004, respectively).

CONCLUSION

The present study demonstrated that CREB gene expression was higher in the ATLL group than ACs, while there was no difference for MAPK. Therefore, this pathway may not strongly involve in the activation of CREB. The CREB may be a prognostic factor for the development of HTLV-I-associated diseases and can be used as a monitoring marker for the efficiency of the therapeutic regime and prognosis.

Structural characteristics and anti-photoaging effect of Pyracantha fortuneana fruit polysaccharides in vitro and in vivo

Pyracantha fortuneana is a cultivated pant extensively cultivated worldwide for its ornamental value and ecological benefits. In this study, a polysaccharide with anti-photoaging activity was extracted and purified from P. fortuneana fruit (PPFP). The structural constitution of PPFP was elucidated by molecular weight determination, FT-IR, monosaccharide composition analysis, smith degradation, methylation, and NMR spectroscopy. The results revealed that PPFP is a macromolecular polysaccharide with a weight-average molecular weight of 70,895 Da. The PPFP is predominantly characterized by →3,6)-β-Galp-(1→, →5,3)-α-Araf-(1 → and →4,2)-α-Xylp-(1→, →4)-β-Galp-(1 → and →4)-β-GalpA-(1 → glycosidic linkages, with t-α-Araf-(1 → and t-α-Glcp-(1 → terminal units. The anti-photoaging activity and potential mechanism of action of PPFP was investigated in vitro and in vivo. Results showed that PPFP exerted anti-photoaging effect on UVB-damaged HaCaT cells by ameliorating cell apoptosis, regulating the mitochondrial membrane potential and oxidative stress level, alleviating the phosphorylation level of the proteins in MAPK pathways, and repairing the expression of tight junction proteins. Moreover, PPFP enhanced the lifespan and diminished the oxidative stress in UVB-injured Caenorhabditis elegans. Collectively, this study comprehensively elucidates the anti-photodamaging potential of P. fortuneana fruit polysaccharide and offers a novel plant-derived adjuvant therapy for the treating photodamage.

Proteomic changes of the bovine blood plasma in response to heat stress in a tropically adapted cattle breed

Background

Identifying molecular mechanisms responsible for the response to heat stress is essential to increase production, reproduction, health, and welfare. This study aimed to identify early biological responses and potential biomarkers involved in the response to heat stress and animal's recovery in tropically adapted beef cattle through proteomic analysis of blood plasma.

Methods

Blood samples were collected from 14 Caracu males during the heat stress peak (HSP) and 16 h after it (heat stress recovery-HSR) assessed based on wet bulb globe temperature index and rectal temperature. Proteome was investigated by liquid chromatography-tandem mass spectrometry from plasma samples, and the differentially regulated proteins were evaluated by functional enrichment analysis using DAVID tool. The protein-protein interaction network was evaluated by STRING tool.

Results

A total of 1,550 proteins were detected in both time points, of which 84 and 65 were downregulated and upregulated during HSR, respectively. Among the differentially regulated proteins with the highest absolute log-fold change values, those encoded by the GABBR1, EPHA2, DUSP5, MUC2, DGCR8, MAP2K7, ADRA1A, CXADR, TOPBP1, and NEB genes were highlighted as potential biomarkers because of their roles in response to heat stress. The functional enrichment analysis revealed that 65 Gene Ontology terms and 34 pathways were significant (P < 0.05). We highlighted those that could be associated with the response to heat stress, such as those related to the immune system, complement system, hemostasis, calcium, ECM-receptor interaction, and PI3K-Akt and MAPK signaling pathways. In addition, the protein-protein interaction network analysis revealed several complement and coagulation proteins and acute-phase proteins as important nodes based on their centrality and edges.

Conclusion

Identifying differentially regulated proteins and their relationship, as well as their roles in key pathways contribute to improve the knowledge of the mechanisms behind the response to heat stress in naturally adapted cattle breeds. In addition, proteins highlighted herein are potential biomarkers involved in the early response and recovery from heat stress in tropically adapted beef cattle.

Inhibition of p38 MAPK/NF-κB p65 signaling pathway activity by rare ginsenosides ameliorates cyclophosphamide-induced premature ovarian failure and KGN cell injury

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng C. A. Mey., one of the most used herbs in the world, shows effective treatment in reproductive injury. Recent studies have proven that the processed product, red ginseng, which is more active than ginseng itself. Therefore, it is speculated that its main functional component, rare ginsenosides (heat-transformed saponin, HTS), may be effective in treating premature ovarian failure (POF), but its efficacy has not yet been experimentally confirmed.

AIM OF THE STUDY

To evaluate whether HTS could attenuate cyclophosphamide-induced inflammation and oxidative damage in POF model rats and the human granulosa-like KGN cell line and protect granulosa cell proliferation.

MATERIAL AND METHODS

HTS were isolated from ginsenosides and high performance liquid chromatography (HPLC) analysis was used to analyze the HTS components. Cyclophosphamide (CP) was used to establish a POF rat model and KGN cell injury model. Reactive oxygen species (ROS) and antioxidant enzyme production was determined using specific assays, while inflammatory cytokine secretion was measured by enzyme-linked immunosorbent assay (ELISA). The proliferative function of granulosa cells was assessed using high-content screening and immunohistochemistry to determine the Ki67 protein level. Protein expression in ovarian tissues and KGN cells was analyzed by Western blotting, quantitative real-time PCR (qRT-PCR) was used to determine the transcriptional changes in ovarian tissues and KGN cells.

RESULTS

In CP-treated POF model rats, HTS significantly decreased malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) levels, increased glutathione oxidase (GSH) levels, and upregulated Ki67 expression in ovarian granulosa cells. In addition, HTS significantly increased cell survival and Ki67 expression levels in CP-treated cells, and superoxide dismutase (SOD) levels were significantly increased. HTS significantly downregulated IL-6, TNF-α, and interleukin-1β (IL-1β) mRNA expression and significantly inhibited nuclear factor kappa-B p65 (NF-κB p65) and p38 mitogen activated protein kinase (p38 MAPK) phosphorylation in POF model rats and KGN cells. Moreover, NF-κB p65 and p38 MAPK levels were significantly increased in ovarian granulosa cells. p65 and p38 protein and gene expression was significantly downregulated.

CONCLUSION

HTS ameliorated CP-induced POF and human granulosa cell injury, possibly by inhibiting inflammation and oxidative damage mediated by the p38 MAPK/NF-κB p65 signaling pathway.

Effects of collagen hydrolysates on UV-induced photoaging mice: Gly-Pro-Hyp as a potent anti-photoaging peptide

This work aimed to investigate the protective effects of collagen hydrolysates containing different contents of Gly-Pro-Xaa tripeptides on UV-induced photoaging mice and to identify potent anti-photoaging peptides. Results showed that oral ingestion of collagen hydrolysates with a higher content of Gly-Pro-Xaa tripeptides (∼11.4%, HCH) dramatically enhanced the absorption of Pro-Hyp, Hyp-Gly, and Gly-Pro-Hyp into the body, which were 1.77-, 2.18-, and 65.07-fold higher in area under the concentration-time curve (AUC) values than that of collagen hydrolysates with a lower content of Gly-Pro-Xaa tripeptides (∼3.8%, LCH), respectively. Furthermore, the protective effects of HCH on the photo-aged skin of mice were significantly stronger than those of LCH in terms of increases in the contents of hyaluronic acid and collagen, improvement in skin elasticity and epidermal thickness, alleviation in inflammation, and decreases in the contents of matrix metalloproteinase-1 (MMP-1) and MMP-3. More importantly, Gly-Pro-Hyp displayed potent anti-photoaging activities comparable to HCH based on an equivalent amount of Hyp. Network pharmacology analysis for potential mechanisms further indicated that Gly-Pro-Hyp might interact with JUN and FOS and regulate IL-17 and TNF signaling pathways. Collectively, our results suggested that HCH had great potential to be applied in functional foods for skin health and Gly-Pro-Hyp was found to be a potent collagen-derived anti-photoaging peptide, which might contribute to the excellent anti-photoaging effects of HCH.

Elaeagnus umbellata Fruit Extract Protects Skin from Ultraviolet-Mediated Photoaging in Hairless Mice

Photoaging refers to the accumulation of skin damage which includes wrinkle formation, loss of elasticity, and epidermal thickening due to repeated ultraviolet (UV) irradiation. The present study investigated the protective effects of Elaeagnus umbellata fruit extract (Elaea) on UV-mediated photoaged skin of SKH1 hairless mice and compared the effects of Elaea with ascorbic acid. Although there was no difference in body weight between groups during experimental period, oral administration of 50-200 mg/kg Elaea once daily for 15 weeks significantly prevented an increase in skin weight, epithelial thickening of epidermis, and apoptosis caused by UV irradiation. Skin replica and histopathological analyses revealed that Elaea dose-dependently decreased wrinkle and microfold formation. In addition, Elaea administration restored UV-mediated reduction in type I collagen and hyaluronan through the inhibition of matrix metalloproteinases and p38 mitogen-activated protein kinase expression. Moreover, Elaea suppressed UV-dependent increases in superoxide anion production, fatty acid oxidation, and protein nitration by up-regulating antioxidant system. Furthermore, Elaea alleviated infiltration of inflammatory cells in UV-irradiated skin. The preventive effects of 100 mg/kg Elaea administration against UV-induced photoaging were similar to those by 100 mg/kg ascorbic acid. Collectively, the present study suggests that the E. umbellata fruit is a promising edible candidate to prevent skin photoaging.

Molecular mechanism of the anti-inflammatory and skin protective effects of Syzygium formosum in human skin keratinocytes

Irradiation injury, especially caused by UVB, of the skin is one of the critical reasons for skin inflammation and damage. The present study aimed to explore the protective effect of Syzygium formosum leafy extract (SFLE) and its mechanism of action against UVB-induced damages of human keratinocytes. In this study, SFLE was prepared from 100 kg dried leaves using industrial-scale processes. We found that SFLE markedly reduced markers of the skin inflammation in UVB-induced pro-inflammatory cytokines. Only 2 μg/mL of SFLE exhibited significantly stronger anti-inflammatory effects than the fivefold concentration of positive control. Intriguingly, an anti-inflammatory enzyme, heme oxygenase-1 expression was significantly induced by SFLE treatment. MMP-3 and -9 were, but not MMP-1, significantly reduced. SFLE inhibited the expression of the MAPK pathway, resulting in a decrease on UVB-induced reactive oxygen species. In conclusion, SFLE can potentially be used to treat skin inflammatory diseases.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01380-4.

Caffeic acid derivative WSY6 protects melanocytes from oxidative stress by reducing ROS production and MAPK activation

Purpose

Vitiligo is a chronic depigmentation disease caused by a loss of functioning melanocytes and melanin from the epidermis. Oxidative stress-induced damage to melanocytes is key in the pathogenesis of vitiligo. WSY6 is a caffeic acid derivative synthesized from epigallocatechin-3-gallate (EGCG). This study is to investigate whether the new chemical WSY6 protected melanocytes from H2O2-induced cell damage and to elucidate the underlying molecular mechanism.

Patients and methods

The present study compared the antioxidative potential of WSY6 with EGCG in hydrogen peroxide (H2O2)-treated PIG1 cells. Western blotting was used to study the protein expression of cyto-c, cleaved-caspase3, cleaved-caspase9, and the activation of MAPK family members, including p38, ERK1/2, JNK and their phosphorylation in melanocytes. ROS assay kit to detect intracellular reactive oxygen species production; CCK8 and lactate dehydrogenase leak assay to detect cytotoxicity.

Results

EGCG and WSY6 ameliorated H2O2-induced oxidative stress damage in PIG1 cells in a does-dependent manner, while WSY6 was much more effective. WSY6 reduced cellular ROS production, cytochrome c release, downregulated caspase-3 and caspase-9 activation. MAPK pathway signaling including phosphorylated p38, ERK and JNK were observed under oxidative stress and can be much protected by pre-treatment of WSY6.

Conclusion

These results indicated that WSY6 could be a more powerful antioxidant than EGCG and protect melanocytes against oxidative cytotoxicity.

Anti-inflammatory, antioxidant and photoprotective activity of standardised Gaultheria procumbens L. leaf, stem, and fruit extracts in UVA-irradiated human dermal fibroblasts

ETHNOPHARMACOLOGICAL RELEVANCE

Gaultheria procumbens L. is a polyphenolic-rich medicinal and food plant. Its leaves, stems, and fruits are traditional anti-inflammatory, antipyretic, antioxidant, and antimicrobial herbal medicines used to treat internal and external inflammation-related ailments, including rheumatic diseases, influenza, the common cold, fever, and skin and periodontal problems. Moreover, G. procumbens leaf extract is used for skin care as an anti-ageing and anti-wrinkle ingredient.

AIM OF THE STUDY

Various environmental factors, especially solar ultraviolet radiation, accelerate skin ageing by promoting oxidative stress and inflammation. Despite the dermoprotective and anti-ageing applications, the impact of G. procumbens on human dermal fibroblasts is unknown. Therefore, the study aimed to evaluate the anti-inflammatory, antioxidant, and photoprotective activity of G. procumbens standardised leaf, stem, and fruit extracts in cellular models, including human dermal fibroblasts (Hs68 cells) under UVA-irradiation, the primary pro-ageing skin stressor.

MATERIALS AND METHODS

Hs68 fibroblasts were pre-treated (24h) with G. procumbens extracts (0.5-100 μg/mL) or reference compounds followed by UVA-irradiation (8 J/cm2). Cell viability and metabolic activity were measured by CCK-8 and MTT assays in human Hs68 and mouse L929 fibroblasts, respectively. The ROS level, SOD, and GST activities were estimated by fluorescence and spectrophotometric techniques. The pro-inflammatory potential (NF-κB transcription factor activation) was checked using THP1-Blue™ NF-κB cells, and the anti-inflammatory activity was studied by measuring IL-8, ICAM-1, and NF-κB levels and phosphorylation of Erk kinase in LPS-stimulated Hs68 cells by spectrophotometry and confocal microscopy. The UVA-induced DNA damage and cell migration were evaluated by comet and scratch assays, respectively.

RESULTS

The extracts did not affect the metabolic activity of mouse L929 fibroblasts and the viability of unirradiated human Hs68 cells. Additionally, the extracts noticeably enhanced the viability of UVA-irradiated Hs68 cells up to 115-120% (p < 0.001) for stem and leaf extract at 25 μg/mL. All extracts in a wide concentration range (0.5-100 μg/mL) did not activate monocytes or induce the NF-κB transcription factor in LPS-stimulated Hs68 fibroblasts. On the other hand, the extracts (5-25 μg/mL) restored the activity of endogenous antioxidant enzymes, i.e., SOD and GST, up to 120-140% (p < 0.001) in the UVA-irradiated Hs68 cells. Moreover, a statistically significant reduction of ROS, IL-8, ICAM-1, and NF-κB levels by up to 48%, 88%, 43%, and 39%, respectively (p < 0.001) and strong suppression of Erk kinase activation was observed for the extracts (25-50 μg/mL) in LPS-stimulated human fibroblasts. The total DNA damage (% tail DNA) in irradiated Hs68 cells was also strongly decreased by up to 66-69% (p < 0.001) at 50 μg/mL. However, the treatment with the extracts did not relevantly enhance the cell migration of Hs68 fibroblasts.

CONCLUSIONS

The results suggest that G. procumbens may effectively protect human skin fibroblast from UVA irradiation. The leaf and stem extracts were the most potent antioxidants, while fruit and stem extracts revealed the strongest anti-inflammatory activity. The observed effects support the traditional use of aerial plant parts (leaves, stems, and fruits) in treating inflammation-related skin disorders cross-linked with oxidative stress and the topical application of Gaultheria extracts as anti-ageing agents intended for skin care.

Sesamin attenuates UVA-induced keratinocyte injury via inhibiting ASK-1-JNK/p38 MAPK pathways

BACKGROUND

Ultraviolet (UV) exposure-stimulated reactive oxygen species (ROS) formation in keratinocytes is a crucial factor in skin aging. Phytochemicals have become widely popular for protecting the skin from UV-induced cell injury. Sesamin (SSM) has been shown to play a role in extensive pharmacological activity and exhibit photoprotective effects.

AIM

To assess the protective effect of SSM on UVA-irradiated keratinocytes and determine its potential antiphotoaging effect.

METHODS

HaCaT keratinocytes pretreated with SSM were exposed to UVA radiation at 8 J/cm2 for 10 min. Cell viability and oxidative stress indicators were evaluated using a cell counting kit-8 and lactate dehydrogenase (LDH), malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD) assay kits. Apoptosis and intracellular ROS levels were analyzed using annexin V-fluorescein isothiocyanate/propyridine iodide and dichlorodihydrofluorescein diacetate staining, respectively. Protein levels of matrix metalloprotein-1 (MMP-1), MMP-9, Bax/Bcl-2, and mitogen-activated protein kinase (MAPK) pathway proteins, phospho-apoptosis signal-regulating kinase-1 (p-ASK-1)/ASK-1, phospho-c-Jun N-terminal protein kinase (p-JNK)/JNK, and p-p38/p38 were determined using western blotting.

RESULTS

Sesamin showed no cytotoxicity until 160 μmol/L on human keratinocytes. Sesamin pretreatment (20 and 40 μM) reversed the suppressed cell viability, increased LDH release and MDA content, decreased cellular antioxidants GSH and SOD, and elevated intracellular ROS levels, which were induced by UVA irradiation. Additionally, SSM inhibited the expression of Bax, MMP-1, and MMP-9 and stimulated Bcl-2 expression. In terms of the regulatory mechanisms, we demonstrated that SSM inhibits the phosphorylation of ASK-1, JNK, and p38.

CONCLUSION

The results suggest that SSM attenuates UVA-induced keratinocyte injury by inhibiting the ASK-1-JNK/p38 MAPK pathways.

Protective potential of frankincense essential oil and its loaded solid lipid nanoparticles against UVB-induced photodamage in rats via MAPK and PI3K/AKT signaling pathways; A promising anti-aging therapy

Frankincense oil has gained increased popularity in skin care, yet its anti-aging effect remains unclear. The current study aimed to investigate the anti-photoaging effect of frankincense (Boswellia papyrifera (Del.) Hochst., Family Burseraceae) essential oil in an in vivo model. The oil was initially extracted by two methods: hydro-distillation (HD) and microwave-assisted hydro-distillation (MAHD). GC/MS analysis revealed the dominance of n-octyl acetate, along with other marker compounds of B. papyrifera including octanol and diterpene components (verticilla 4(20) 7, 11-triene and incensole acetate). Thereafter, preliminary investigation of the anti-collagenase and anti-elastase activities of the extracted oils revealed the superior anti-aging effect of HD-extracted oil (FO), comparable to epigallocatechin gallate. FO was subsequently formulated into solid lipid nanoparticles (FO-SLNs) via high shear homogenization to improve its solubility and skin penetration characteristics prior to in vivo testing. The optimimal formulation prepared with 0.5% FO, and 4% Tween® 80, demonstrated nanosized spherical particles with high entrapment efficiency percentage and sustained release for 8 hours. The anti-photoaging effect of FO and FO-SLNs was then evaluated in UVB-irradiated hairless rats, compared to Vitamin A palmitate as a positive standard. FO and FO-SLNs restored the antioxidant capacity (SOD and CAT) and prohibited inflammatory markers (IL6, NFκB p65) in UVB-irradiated rats via downregulation of MAPK (pERK, pJNK, and pp38) and PI3K/AKT signaling pathways, alongside upregulating TGF-β expression. Subsequently, our treatments induced Procollagen I synthesis and downregulation of MMPs (MMP1, MMP9), where FO-SLNs exhibited superior anti-photoaging effect, compared to FO and Vitamin A, highlighting the use of SLNs as a promising nanocarrier for FO. In particular, FO-SLNs revealed normal epidermal and dermal histological structures, protected against UVβ-induced epidermal thickness and dermal collagen degradation. Our results indicated the potential use of FO-SLNs as a promising topical anti-aging therapy.

Anti-Wrinkling Effect of 3,4,5-tri-O-caffeoylquinic Acid from the Roots of Nymphoides peltata through MAPK/AP-1, NF-κB, and Nrf2 Signaling in UVB-Irradiated HaCaT Cells

Nymphoides peltata has been widely used pharmacologically in traditional Chinese medicine to treat heat strangury and polyuria. The aim of this study was to isolate the bioactive components from N. peltata and evaluate their potential use as antioxidant and anti-wrinkle agents. Phytochemical investigation of the methanolic extract of N. peltata roots led to the isolation of 15 compounds (1-15), which were structurally determined as α-spinasterol (1), 3-O-β-D-glucopyranosyl-oleanolic acid 28-O-β-D-glucuronopyranoside (2), 4-hydroxybenzoic acid (3), protocatechuic acid (4), vanillic acid (5), p-coumaric acid (6), caffeic acid (7), ferulic acid (8), neochlorogenic acid (neo-CQA) (9), chlorogenic acid (CQA) (10), cryptochlorogenic acid (crypto-CQA) (11), isochlorogenic acid B (3,4-DCQA) (12), isochlorogenic acid A (3,5-DCQA) (13), isochlorogenic acid C (4,5-DCQA) (14), and 3,4,5-tri-O-caffeoylquinic acid (TCQA) (15). Of these 15 compounds, compound 2 was a new oleanane saponin, the chemical structure of which was characterized by 1D and 2D nuclear magnetic resonance (NMR) spectroscopic data and high-resolution electrospray ionization mass spectrometry (HRESIMS), as well as chemical reaction. Biological evaluation of the isolated compounds revealed that 3,4,5-tri-O-caffeoylquinic acid (TCQA) significantly improved Nrf2 levels in an Nrf2-ARE reporter HaCaT cell screening assay. TCQA was found to potently inhibit the Nrf2/HO-1 pathway and to possess strong anti-wrinkle activity by modulating the MAPK/NF-κB/AP-1 signaling pathway and thus inhibiting MMP-1 synthesis in HaCaT cells exposed to UVB. Our results suggest that TCQA isolated from N. peltata might be useful for developing effective antioxidant and anti-wrinkle agents.

Plant Extracts as Skin Care and Therapeutic Agents

Natural ingredients have been used for centuries for skin treatment and care. Interest in the health effects of plants has recently increased due to their safety and applicability in the formulation of pharmaceuticals and cosmetics. Long-known plant materials as well as newly discovered ones are increasingly being used in natural products of plant origin. This review highlights the beneficial effects of plants and plant constituents on the skin, including moisturizing (e.g., Cannabis sativa, Hydrangea serrata, Pradosia mutisii and Carthamus tinctorius), anti-aging (e.g., Aegopodium podagraria, Euphorbia characias, Premna odorata and Warburgia salutaris), antimicrobial (e.g., Betula pendula and Epilobium angustifolium), antioxidant (e.g., Kadsura coccinea, Rosmarinus officinalis, Rubus idaeus and Spatholobus suberectus), anti-inflammatory (e.g., Antidesma thwaitesianum, Helianthus annuus, Oenanthe javanica, Penthorum chinense, Ranunculus bulumei and Zanthoxylum bungeanum), regenerative (e.g., Aloe vera, Angelica polymorpha, Digitaria ciliaris, Glycyrrihza glabra and Marantodes pumilum), wound healing (e.g., Agrimonia eupatoria, Astragalus floccosus, Bursera morelensis, Jatropha neopauciflora and Sapindus mukorossi), photoprotective (e.g., Astragalus gombiformis, Calea fruticose, Euphorbia characias and Posoqueria latifolia) and anti-tyrosinase activity (e.g., Aerva lanata, Bruguiera gymnorhiza, Dodonaea viscosa, Lonicera japonica and Schisandra chinensis), as well as their role as excipients in cosmetics (coloring (e.g., Beta vulgaris, Centaurea cyanus, Hibiscus sabdariffa and Rubia tinctiorum), protective and aromatic agents (e.g., Hyssopus officinalis, Melaleuca alternifolia, Pelargonium graveolens and Verbena officinalis)).

Toxic Interaction Between Solar Radiation and Cigarette Smoke on Primary Human Keratinocytes

Solar radiation and cigarette smoke are two environmental risk factors known to affect skin integrity. Although the toxic effects of these factors on skin have been widely studied separately, few studies have focused on their interaction. The objective of this study was to evaluate and understand the synergistic harmful effects of cigarette smoke and solar rays on human primary keratinocytes. The keratinocytes were exposed to cigarette smoke extract (CSE) and then irradiated with a solar simulator light (SSL). The viability, as determined by measuring metabolic activity of skin cells, and the levels of global reactive oxygen species (ROS) were evaluated after exposure to CSE and SSL. The combination of 3% CSE with 29 kJ m-2 UVA caused a decrease of 81% in cell viability, while with 10% to 20% CSE, the cell viability was null. This phototoxicity was accompanied by an increase in singlet oxygen but a decrease in type I ROS when CSE and SSL were combined in vitro. Surprisingly, an increase in the CSE's total antioxidant capacity was also observed. These results suggest a synergy between the two environmental factors in their effect on skin cells, and more precisely a phototoxicity causing a drastic decrease in cell viability.

Oridonin suppresses gastric cancer SGC-7901 cell proliferation by targeting the TNF-alpha/androgen receptor/TGF-beta signalling pathway axis

Statistics provided by GLOBOCAN list gastric cancer as the sixth most common, with a mortality ranking of third highest for the year 2020. In China, a herb called Rabdosia rubescens (Hemsl.) H.Hara, has been used by local residents for the treatment of digestive tract cancer for hundreds of years. Oridonin, the main ingredient of the herb, has a curative effect for gastric cancer, but the mechanism has not been previously clarified. This study mainly aimed to investigate the role of TNF-alpha/Androgen receptor/TGF-beta signalling pathway axis in mediating the proliferation inhibition of oridonin on gastric cancer SGC-7901 cells. MTT assay, cell morphology observation assay and fluorescence assay were adopted to study the efficacy of oridonin on cell proliferation. The network pharmacology was used to predict the pathway axis regulated by oridonin. Western blot assay was adopted to verify the TNF-α/Androgen receptor/TGF-β signalling pathway axis regulation on gastric cancer by oridonin. The results showed Oridonin could inhibit the proliferation of gastric cancer cells, change cell morphology and cause cell nuclear fragmentation. A total of 11signaling pathways were annotated by the network pharmacology, among them, Tumour necrosis factor alpha (TNF-α) signalling pathway, androgen receptor (AR) signalling pathway and transforming growth factor (TGF-β) signalling pathway account for the largest proportion. Oridonin can regulate the protein expression of the three signalling pathways, which is consistent with the results predicted by network pharmacology. These findings indicated that oridonin can inhibit the proliferation of gastric cancer SGC-7901 cells by regulating the TNF-α /AR /TGF-β signalling pathway axis.

Protective effect and mechanism research of Phyllanthus emblica Linn. fruit extract on UV-induced photodamage in keratinocytes

Ultraviolet (UV) irradiation causes acute and chronic cutaneous effects that may result in photodamage and photoaging. Epidermis keratinocytes, as the closest surface of skin, are susceptible to damage from UV rays. Phyllanthus emblica Linn. fruit (PE) extract, as a medicine and food dual-use plant, contains high levels of polyphenols and possesses multiple pharmacological properties. The present study investigated common and different molecular mechanisms and signaling pathway activations of UVA and UVB stimulated cell damage and photoprotective effect of PE extract against UVA and UVB by Methyl Thiazolyl Tetrazolium (MTT) method, Elisa assay, flow cytometry, differentially expressed genes analysis and western blot analysis. The results showed that UVA exposure (10 J/cm2) reduced HaCaT cell viability significantly, increased the apoptosis rate, elevated intracellular reactive oxygen species level and reduced antioxidant enzyme activities. And UVA irradiation could inhibit the ERK/TGF-β/Smad signaling pathway to downregulate collagen I, collagen III and elastin expressions, resulting in the photoaging of skin cells. We also found UVB exposure (30 mJ/cm2) caused HaCaT cell damage, promoted apoptosis, increased ROS production and induced the release of proinflammatory cytokines (IL-1α, IL-6 and PGE2). Further, in HaCaT cells, UVB ray was able to induce the activation of apoptosis markers (cleaved PARP1 and cleaved caspase3) through the MAPK/AP-1 signaling pathway using western blot analysis. Pre-treatment of PE extract prevented the UVA and UVB induced photoaging and injury in HaCaT cells through activation of ERK/TGF-β/Smad pathway and inhibition of MAPK/AP-1 pathway, respectively. Therefore, PE extract has the potential to be used as an oral and topical preparation against skin aging and injury induced by UVA and UVB.

Molecular basis of skin photoaging and therapeutic interventions by plant-derived natural product ingredients: A comprehensive review

Skin areas exposed to ultraviolet radiation (UV) from sunlight are more prone to photoaging than unexposed areas evidenced by several signs which include skin dryness, irregular pigmentation, lentigines, hyperpigmentation, wrinkling, and decreased elasticity. Plant-based natural product ingredients with therapeutic potential against skin photoaging are gaining more attention. This article aims the reviewing the research work done in exploring the cellular and molecular mechanisms involved in UV-induced skin photoaging, followed by summarizing the mechanistic insights involved in its therapeutics by natural product-based ingredients. In the mechanistic section of the convoluted procedure of photoaging, we described the effect of UV radiation (UVR) on different cellular macromolecules (direct damage) and subsequently, the deleterious consequences of UVR-generated reactive oxygen species (indirect damage) and signaling pathways activated or inhibited by UV induced ROS generation in various cellular pathologies of skin photoaging like inflammation, extracellular matrix degradation, apoptosis, mitochondrial dysfunction, and immune suppression. We also discussed the effect of UV radiation on the adipose tissue, and transient receptor potential cation channel V of photoaging skin. In the past few decades, mechanistic studies performed in this area have deciphered various therapeutic targets, opening avenues for different available therapeutic options against this pathological condition. So the remaining portion of the review deals with various natural product-based therapeutic agents available against skin photodamage.

Therapeutic and cosmeceutical role of glycosylated natural products in dermatology

Natural products (NPs) remain the primary source of pharmacologically active candidates for drug discovery. Since time immemorial, NPs have attracted considerable attention because of their beneficial skin effects. Moreover, there has been a great interest in using such products for the cosmetics industry in the past few decades, bridging the gap between modern and traditional medicine. Terpenoids, Steroids, and Flavonoids having glycosidic attachment have proven biological effects with a positive impact on human health. NPs derived glycosides are mainly found in fruits, vegetables, and plants, and most of them have a special reverence in traditional and modern medicine for disease prevention and treatment. A literature review was performed using scientific journals, Google scholar, Scifinder, PubMED, and Google patents. These scientific articles, documents, and patents establish the significance of glycosidic NPs in the areas of dermatology. Considering the human inclination to the usage of NPs rather than synthetic or inorganic drugs (especially in the area of skin care), in the present review we have discussed the worth of NP glycosides in beauty care and skin-related therapeutics and the mechanistic pathways involved.

Preparation of CPD Photolyase Nanoliposomes Derived from Antarctic Microalgae and Their Effect on UVB-Induced Skin Damage in Mice

UVB radiation is known to trigger the block of DNA replication and transcription by forming cyclobutane pyrimidine dimer (CPD), which results in severe skin damage. CPD photolyase, a kind of DNA repair enzyme, can efficiently repair CPDs that are absent in humans and mice. Although exogenous CPD photolyases have beneficial effects on skin diseases, the mechanisms of CPD photolyases on the skin remain unknown. Here, this study prepared CPD photolyase nanoliposomes (CPDNL) from Antarctic Chlamydomonas sp. ICE-L, which thrives in harsh, high-UVB conditions, and evaluated their protective mechanisms against UVB-induced damage in mice. CPDNL were optimized using response surface methodology, characterized by a mean particle size of 105.5 nm, with an encapsulation efficiency of 63.3%. Topical application of CPDNL prevented UVB-induced erythema, epidermal thickness, and wrinkles in mice. CPDNL mitigated UVB-induced DNA damage by significantly decreasing the CPD concentration. CPDNL exhibited antioxidant properties as they reduced the production of reactive oxygen species (ROS) and malondialdehyde. Through activation of the NF-κB pathway, CPDNL reduced the expression of pro-inflammatory cytokines including IL-6, TNF-α, and COX-2. Furthermore, CPDNL suppressed the MAPK signaling activation by downregulating the mRNA and protein expression of ERK, JNK, and p38 as well as AP-1. The MMP-1 and MMP-2 expressions were also remarkably decreased, which inhibited the collagen degradation. Therefore, we concluded that CPDNL exerted DNA repair, antioxidant, anti-inflammation, and anti-wrinkle properties as well as collagen protection via regulation of the NF-κB/MAPK/MMP signaling pathways in UVB-induced mice, demonstrating that Antarctic CPD photolyases have the potential for skincare products against UVB and photoaging.

SNA077, an Extract of Marine Streptomyces sp., Inhibits Melanogenesis by Downregulating Melanogenic Proteins via Inactivation of cAMP/PKA/CREB Signaling

Excess melanin in skin is known to be the main cause of hyper-pigmentary skin diseases such as freckles and lentigo. This study aimed to evaluate the depigmenting efficacy of an extract from the marine microorganism strain, Streptomyces sp. SNA077. To determine the anti-melanogenic efficacy of SNA077, we assessed the melanin contents of SNA077-treated B16, Melan-a, and MNT-1 cells. We observed the expression of key enzymes in melanogenesis via qRT-PCR and Western blot analyses. We further estimated the skin-whitening effect of SNA077 using a skin-equivalent model. SNA077 dramatically decreased the melanin production of B16 cells, Melan-a, and MNT-1 cells. In B16 cells treated with SNA077, the activity of cellular tyrosinase was clearly inhibited. In addition, the mRNA and protein expression levels of melanogenic genes were suppressed by SNA077 treatment in B16 and MNT-1 cells. Upstream of tyrosinase, the expression levels of phospho-CREB, phospho-p38, PKA activity, cyclic AMP production, and MC1R gene expression were inhibited by SNA077. Finally, SNA077 clearly showed a skin-brightening effect with a reduced melanin content in the skin tissue model. Collectively, our results suggest for the first time that an extract of marine Streptomyces sp. SNA077 could be a novel anti-melanogenic material for skin whitening.

First evidence of dermo-protective activity of marine sulfur-containing histidine compounds

Among natural products, ovothiol (ovo), produced by marine invertebrates, bacteria, and microalgae, is receiving increasing interest for its unique antioxidant properties. Recently, ovo has been shown to exhibit anti-inflammatory activity in an in vitro model of endothelial dysfunction and in an in vivo model of liver fibrosis. The aim of this study was to evaluate the effect of ovo and its precursor 5-thiohistidine (5-thio) in comparison with ergothioneine (erg), in human skin cells and tissues upon inflammation. We used both an in vitro and ex vivo model of human skin, represented by a keratinocytes cell line (HaCaT) and skin biopsies, respectively. We observed that ovo, 5-thio, and erg were not cytotoxic in HaCaT cells, but instead exerted a protective function against TNF-α -induced inflammation. In order to get insights on their mechanism of action, we performed western blot analysis of ERK and JNK, as well as sub-cellular localization of Nrf2, a key mediator of the anti-inflammatory response. The results indicated that the pre-treatment with ovo, 5-thio, and erg differently affected the phosphorylation of ERK and JNK. However, all the three molecules promoted the accumulation of Nrf2 in the nucleus of HaCaT cells. In addition, gene expression analysis by RTqPCR and ELISA assays performed in ex vivo human skin tissues pre-treated with thiohistidines and then inflamed with IL-1β revealed a significant downregulation of IL-8, TNF-α and COX-2 genes and a concomitant significant decrease in the cytokines IL-6, IL-8 and TNF-α production. Moreover, the protective action of ovo and 5-thio resulted to be stronger when compared with dexamethasone, a corticosteroid drug currently used to treat skin inflammatory conditions. Our findings suggest that ovo and 5-thio can ameliorate skin damage and may be used to develop natural skin care products to prevent the inflammatory status induced by environmental stressors and aging.

UVA Radiation, DNA Damage, and Melanoma

Melanoma is a lethal type of skin tumor that has been linked with sunlight exposure chiefly in fair-skinned human populations. Wavelengths from the sun that can reach the earth's surface include UVA radiation (320-400 nm) and UVB radiation (280-320 nm). UVB effectively induces the formation of dimeric DNA photoproducts, preferentially the cyclobutane pyrimidine dimers (CPDs). The characteristic UVB signature mutations in the form of C to T mutations at dipyrimidine sequences are prevalent in melanoma tumor genomes and have been ascribed to deamination of cytosines within CPDs before DNA polymerase bypass. However, evidence from epidemiological, animal, and other experimental studies also suggest that UVA radiation may participate in melanoma formation. The DNA damage relevant for UVA includes specific types of CPDs at TT sequences and perhaps oxidative DNA damage to guanine, both induced by direct or indirect, photosensitization-mediated chemical and biophysical processes. We summarize the evidence for a potential role of UVA in melanoma and discuss some of the mechanistic pathways of how UVA may induce mutagenesis in melanocytes.

Grifola frondosa Extract Containing Bioactive Components Blocks Skin Fibroblastic Inflammation and Cytotoxicity Caused by Endocrine Disrupting Chemical, Bisphenol A

Grifola frondosa (GF), a species of Basidiomycotina, is widely distributed across Asia and has been used as an immunomodulatory, anti-bacterial, and anti-cancer agent. In the present study, the pharmacological activity of the GF extract against an ecotoxicological industrial chemical, bisphenol A (BPA) in normal human dermal fibroblasts (NHDFs), was investigated. GF extract containing naringin, hesperidin, chlorogenic acid, and kaempferol showed an inhibitory effect on cell death and inflammation induced by BPA in the NHDFs. For the cell death caused by BPA, GF extract inhibited the production of reactive oxygen species responsible for the unique activation of the extracellular signal-regulated kinase. In addition, GF extract attenuated the expression of apoptosis-related proteins (Bax, Bcl-2, and cleaved caspase-3) and the pro-inflammatory cytokine IL-1β by the suppression of the redox-sensitive transcription factor, nuclear factor-kappa B (NF-κB) in BPA-treated NHDFs. For the inflammation triggered by BPA, GF extract blocked the inflammasome-mediated caspase-1 activation that leads to the secretion of IL-1β protein. These results indicate that the GF extract is a functional antioxidant that prevents skin fibroblastic pyroptosis induced by BPA.

Unravelling the molecular mechanism of mutagenic factors impacting human health

Environmental mutagens are chemical and physical substances in the environment that has a potential to induce a wide range of mutations and generate multiple physiological, biochemical, and genetic modifications in humans. Most mutagens are having genotoxic effects on the following generation through germ cells. The influence of germinal mutations on health will be determined by their frequency, nature, and the mechanisms that keep a specific mutation in the population. Early prenatal lethal mutations have less public health consequences than genetic illnesses linked with long-term medical and social difficulties. Physical and chemical mutagens are common mutagens found in the environment. These two environmental mutagens have been associated with multiple neurological disorders and carcinogenesis in humans. Thus in this study, we aim to unravel the molecular mechanism of physical mutagens (UV rays, X-rays, gamma rays), chemical mutagens (dimethyl sulfate (DMS), bisphenol A (BPA), polycyclic aromatic hydrocarbons (PAHs), 5-chlorocytosine (5ClC)), and several heavy metals (Ar, Pb, Al, Hg, Cd, Cr) implicated in DNA damage, carcinogenesis, chromosomal abnormalities, and oxidative stress which leads to multiple disorders and impacting human health. Biological tests for mutagen detection are crucial; therefore, we also discuss several approaches (Ames test and Mutatox test) to estimate mutagenic factors in the environment. The potential risks of environmental mutagens impacting humans require a deeper basic knowledge of human genetics as well as ongoing research on humans, animals, and their tissues and fluids.

Uncovering Streptomyces-Derived Compounds as Cosmeceuticals for the Development of Improved Skin Photoprotection Products: An In Silico Approach to Explore Multi-Targeted Agents

The search for novel photoprotective substances has become a challenge in cosmeceutical research. Streptomyces-derived compounds can serve as a promising source of photoprotective agents to formulate skin photoprotection products, such as sunscreens. This study aimed to identify specialized metabolites with the potential to modulate UV-induced cellular damage in the skin by identifying potential multi-target-directed ligands. Using a combination of ligand- and target-based virtual screening approaches, a public compound library comprising 6524 Streptomyces-derived specialized metabolites was studied for their photoprotective capability. The compounds were initially filtered by safety features and then examined for their ability to interact with key targets in the photodamage pathway by molecular docking. A set of 50 commercially available UV filters was used as the benchmark. The protein–ligand stability of selected Streptomyces-derived compounds was also studied by molecular dynamics (MD) simulations. From the compound library, 1981 compounds were found to meet the safety criteria for topically applied products, such as low skin permeability and low or non-toxicity-alerting substructures. A total of 34 compounds had promising binding scores against crucial targets involved in UV-induced photodamage, such as serotonin-receptor subtype 5-HT2A, platelet-activating factor receptor, IL-1 receptor type 1, epidermal growth factor receptor, and cyclooxygenase-2. Among these compounds, aspergilazine A and phaeochromycin F showed the highest ranked interactions with four of the five targets and triggered complex stabilization over time. Additionally, the predicted UV-absorbing profiles also suggest a UV-filtering effect. Streptomyces is an encouraging biological source of compounds for developing topical products. After in silico protein–ligand interactions, binding mode and stabilization of aspergilazine A and phaeochromycin F led to the discovery of potential candidates as photodamage multi-target inhibitors. Therefore, they can be further explored for the formulation of skin photoprotection products.

Activation of the JNKs/ATM-p53 axis is indispensable for the cytoprotection of dermal fibroblasts exposed to UVB radiation

Although UVB radiation is mainly absorbed by the epidermis, ~5-10% of its photons reach and affect the upper part of the dermis. Physiologically relevant UVB doses, able to provoke erythema, induce apoptosis in human dermal fibroblasts in vitro, as well as in the dermis of SKH-1 mice. Given the sparse and even contradictory existing information on the effect of UVB radiation on dermal fibroblasts' viability, aim of this work was to unravel the crucial signaling pathways regulating the survival of UVB-treated human dermal fibroblasts. We found that UVB radiation immediately stimulates the phosphorylation of MAPK family members, as well as Akt, and is genotoxic leading to the delayed ATM-p53 axis activation. Akt phosphorylation after UVB radiation is EGFR-mediated and EGFR inhibition leads to a further decrease of viability, while the Akt activator SC79 rescues fibroblasts to an extent by a mechanism involving Nrf2 activation. The known Nrf2 activator sulforaphane also exerts a partial protective effect, although by acting in a distinct mechanism from SC79. On the other hand, inhibition of JNKs or of the ATM-p53 axis leads to a complete loss of viability after UVB irradiation. Interestingly, JNKs activation is necessary for p53 phosphorylation, while the ATM-p53 pathway is required for the long-term activation of JNKs and Akt, reassuring the protection from UVB. Although UVB radiation results in intense and prolonged increase of intracellular ROS levels, classical anti-oxidants, such as Trolox, are unable to affect Akt, JNKs, or p53 phosphorylation and to reverse the loss of fibroblasts' viability. Collectively, here we provide evidence that the main viability-regulating UVB-triggered biochemical pathways act synergistically towards the protection of human dermal fibroblasts, with EGFR/Akt and Nrf2 serving as auxiliary anti-apoptotic machineries, while JNKs/ATM-p53 activation and interplay being overriding and indispensable for the perpetuation of cellular defense and the maintenance of cell viability.

Dimethyl Itaconate Reduces α-MSH-Induced Pigmentation via Modulation of AKT and p38 MAPK Signaling Pathways in B16F10 Mouse Melanoma Cells

Dimethyl itaconate (DMI) exhibits an anti-inflammatory effect. Activation of nuclear factor erythroid 2-related factor 2 (NRF2) is implicated in the inhibition of melanogenesis. Therefore, DMI and itaconic acid (ITA), classified as NRF2 activators, have potential uses in hyperpigmentation reduction. The activity of cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB), an important transcription factor for MITF gene promoter, is regulated by glycogen synthase kinase 3β (GSK3β) and protein kinase A (PKA). Here, we investigated the inhibitory effect of ITA and DMI on alpha-melanocyte-stimulating hormone (α-MSH)-induced MITF expression and the modulatory role of protein kinase B (AKT) and GSK3β in melanogenesis in B16F10 mouse melanoma cells. These cells were incubated with α-MSH alone or in combination with ITA or DMI. Proteins were visualized and quantified using immunoblotting and densitometry. Compared to ITA, DMI treatment exhibited a better inhibitory effect on the α-MSH-induced expression of melanogenic proteins such as MITF. Our data indicate that DMI exerts its anti-melanogenic effect via modulation of the p38 mitogen-activated protein kinase (MAPK) and AKT signaling pathways. In conclusion, DMI may be an effective therapeutic agent for both inflammation and hyperpigmentation.

Non-coding RNAs in photoaging-related mechanisms: a new paradigm in skin health

The aging of skin is a biological process affected by environmental or genetic factors. Exposure to ultraviolet (UV) radiation is the main environmental factor causing skin aging. Cumulative UV-induced photodamage of the skin tissue is associated with premature cellular senescence, extracellular degradation, and inflammatory responses in photoaging processes. Non-coding RNAs (ncRNAs) are untranslated transcripts and master regulators of protein-coding genes. ncRNAs have a critical regulatory role in maintaining skin structure, skin barrier function, morphogenesis, and development. Altered ncRNA expression has been reported in various skin disorders such as photoaging and skin cancers. ncRNAs contribute to the suppression and promotion of photoaging by modulating signaling pathways such as mitogen-activated protein kinase (MAPK) pathway and regulating inflammatory cytokines, matrix metalloproteinases (MMPs), and senescence-associated genes. Elucidation of the functions of ncRNAs will improve the identification of molecular mechanisms underlying photoaging, and can be used in the development of therapeutic approaches in skin health and prevention of sun-induced aging. This review summarized the currently described ncRNAs and their functions in photoaging.

The Prospects of Swietenia macrophylla King in Skin Care

The importance of cosmetics in our lives is immeasurable. Covering items from daily personal hygienic products to skincare, it has become essential to consumers that the items that they use are safe and effective. Since natural products are from natural sources, and therefore considered “natural” and “green” in the public’s eyes, the rise in demand for such products is not surprising. Even so, factoring in the need to remain on trend and innovative, cosmetic companies are on a constant search for new ingredients and inventive new formulations. Based on numerous literature, the seed of Swietenia macrophylla has been shown to possess several potential “cosmetic-worthy” bioproperties, such as skin whitening, photoprotective, antioxidant, antimicrobial, etc. These properties are vital in the cosmetic business, as they ultimately contribute to the “ageless” beauty that many consumers yearn for. Therefore, with further refinement and research, these active phytocompounds may be a great contribution to the cosmetic field in the near future.

Are TRPA1 and TRPV1 channel-mediated signalling cascades involved in UVB radiation-induced sunburn?

Burn injuries are underappreciated injuries associated with substantial morbidity and mortality. Overexposure to ultraviolet (UV) radiation has dramatic clinical effects in humans and is a significant public health concern. Although the mechanisms underlying UVB exposure are not fully understood, many studies have made substantial progress in the pathophysiology of sunburn in terms of its molecular aspects in the last few years. It is well established that the transient receptor potential ankyrin 1 (TRPA1), and vanilloid 1 (TRPV1) channels modulate the inflammatory, oxidative, and proliferative processes underlying UVB radiation exposure. However, it is still unknown which mechanisms underlying TRPV1/A1 channel activation are elicited in sunburn induced by UVB radiation. Therefore, in this review, we give an overview of the TRPV1/A1 channel-mediated signalling cascades that may be involved in the pathophysiology of sunburn induced by UVB radiation. These data will undoubtedly help to explain the various features of sunburn and contribute to the development of novel therapeutic approaches to better treat it.

Anti-Photoaging Effect of Hydrolysates from Pacific Whiting Skin via MAPK/AP-1, NF-κB, TGF-β/Smad, and Nrf-2/HO-1 Signaling Pathway in UVB-Induced Human Dermal Fibroblasts

Chronic exposure to ultraviolet (UV) light promotes the breakdown of collagen in the skin and disrupts the extracellular matrix (ECM) structure, leading to skin wrinkling. Pacific whiting (Merluccius productus) is a fish abundant on the Pacific coast. In the current study, we investigated the anti-wrinkle effect of hydrolysate from Pacific whiting skin gelatin (PWG) in UVB-irradiated human dermal fibroblasts and the molecular mechanisms involved. PWG effectively restored type 1 procollagen synthesis reduced by UVB-irradiation. Also, we found that PWG inhibited collagen degradation by inhibiting MMP1 expression. Furthermore, PWG decreased cytokines TNF-α, IL-6, and IL-1β associated with inflammatory responses and increased antioxidant enzymes, HO-1, SOD, GPx, CAT, and GSH content, a defense system against oxidative stress. In terms of molecular mechanisms, PWG increased collagen synthesis through activating the transforming growth factor β (TGF-β)/Smad pathway and decreased collagen degradation through inhibiting the mitogen-activated protein kinases/activator protein 1 (MAPK/AP-1) pathway. It also suppressed the inflammatory response through suppressing the nuclear factor-κB (NF-κB) pathway and increased antioxidant enzyme activity through activating the nuclear factor erythroid 2/heme oxygenase 1 (Nrf-2/HO-1) pathway. These multi-target mechanisms suggest that PWG may serve as an effective anti-photoaging material.

Protective effect of γ-glutamylcysteine against UVB radiation in NIH-3T3 cells

BACKGROUND

Ultraviolet (UV) radiation-induced oxidative stress is the main cause of photodamage to the skin. Glutathione (GSH) serves important physiological functions, including scavenging oxygen-free radicals and maintaining intracellular redox balance. γ-glutamylcysteine (γ-GC), as an immediate precursor of GSH and harboring antioxidant and anti-inflammatory properties, represents an unexplored option for skin photodamage treatment.

PURPOSE

The purpose of this study was to investigate whether γ-GC can reduce UVB-induced NIH-3T3 cell damage.

METHODS

The experimental groups were as follows: control, UVB radiation, UVB radiation after pretreatment with γ-GC. Cell counting kit-8 (CCK-8) assays were used to measure cell proliferation, flow cytometry, and immunoblotting to detect the apoptosis rate and apoptosis-associated proteins. The levels of Reactive Oxygen Species (ROS), Superoxide Dismutase (SOD), and GSH/GSSG (oxidized GSH) were measured to assess oxidative stress. Immunoblotting and immunofluorescence were used to detect DNA damage. The members of the MAPK signaling pathways were detected by immunoblotting.

RESULTS

UVB irradiation significantly reduced cell viability and destroyed the oxidative defense system. Pretreatment with γ-GC reduced UVB-induced cytotoxicity, restored the oxidation defense system, and inhibited activation of the MAPK pathway. It also reduced the apoptosis rate, downregulated the levels of cleaved caspase 3 and cleaved PARP. Furthermore, pretreatment with γ-GC reduced the accumulation of γH2AX after UVB radiation exposure, indicating that γ-GC could protect cells from DNA damage.

CONCLUSION

γ-GC protected NIH-3T3 from damage caused by UVB irradiation. The photoprotective effect of γ-GC is mediated via strengthening the endogenous antioxidant defense system, which prevents DNA damage and inhibits the activation of the MAPK pathway.

BRAF Inhibitor Resistance in Melanoma: Mechanisms and Alternative Therapeutic Strategies

OPINION STATEMENT

Melanoma is caused by a variety of somatic mutations, and among these mutations, BRAF mutation occurs most frequently and has routinely been evaluated as a critical diagnostic biomarker in clinical practice. The introduction of targeted agents for BRAF-mutant melanoma has significantly improved overall survival in a large proportion of patients. However, there is BRAF inhibitor resistance in most patients, and its mechanisms are complicated and need further clarification. Additionally, treatment approaches to overcome resistance have evolved rapidly, shifting from monotherapy to multimodality treatment, which has dramatically improved patient outcomes in clinical trials and practice. This review highlights the mechanisms of BRAF inhibitor resistance in melanoma and discusses the current state of its therapeutic approaches that can be further explored in clinical practice.

Programmed gene expression change in mouse skin after ultraviolet radiation damage

Ultraviolet (UV) radiation is a major cause of skin damage and carcinogenesis. Here, we systematically analyse the acute gene expression change in skin in vivo after UV exposure, aiming to establish the common C57BL/6 mouse strain as a convenient model for future pathological research and drug discovery. The back fur of C57BL/6 mice was depilated, and a mixed UV light source was used to irradiate the skin. Full-thickness skin samples were collected at 0, 0.5, 2, 6, 12 and 24 h. Total RNAs were extracted and subjected to RNA sequencing analysis. We found that the gene expression change in mouse skin is highly similar to previous reports in human skin. These include down-regulation of differentiation-related genes and extracellular matrix genes, and up-regulation of cytokine/chemokine genes. An early wave of activator protein 1 (AP-1) expression is induced, whereas activation of the p53 pathway is not significant. The impact of the AP-1 transcription factors and the antioxidant tea polyphenols is discussed. The analysis of acute gene expression change in skin after UV irradiation provides a starting point to investigate how the skin responds to genotoxic stress.

High-Throughput RNA Sequencing Reveals the Effect of NB-UVB Phototherapy on Major Inflammatory Molecules of Lesional Psoriasis

OBJECTIVE

To identify the narrowband ultraviolet B (NB-UVB)-induced molecular mechanisms that may account for their anti-inflammatory efficacy, gene expression and transcriptome profiling, which were performed using advanced molecular techniques.

METHODS

This research was conducted on patients with moderate-to-severe plaque-type psoriasis who received NB-UVB treatment. RNA sequencing (RNA-Seq) was conducted to assay the transcriptomes and identify the differentially expressed transcripts that had been enriched during the major pathway analysis.

RESULTS

Clinical improvement of psoriasis by NB-UVB therapy is linked to the suppression of the "immunological signaling pathways" and "cell cycle regulatory, growth and proliferation pathways" which are critical to the pathogenesis of the disease. In addition, these results were further substantiated by demonstrating that NB-UVB therapy has a significant effect on keratinocyte differentiation and affects the regulation of genes and inflammatory mediators that are related to cell proliferation and apoptosis. Moreover, NB-UVB phototherapy is also involved with the downregulation of toll-like receptors signaling in lesional psoriasis.

CONCLUSION

NB-UVB is an effective treatment for psoriasis. Our study supports the conclusion that the clinical effectiveness of NB-UVB therapy is based on the suppression of a broad range of inflammatory signaling pathways, gene expression of inflammatory cytokines and increased expressions of anti-inflammatory signaling pathways in psoriatic skin. This is the first study that applied advanced molecular techniques to investigate phototherapy as a new key to unlock genetic knowledge and create novel information. Ultimately, the goal is to increase medical knowledge and improve the patient care of psoriasis.