UVB-induced Reactive Oxygen Species Research Articles

IRE1α regulates ROS and immune responses after UVB irradiation

UV irradiation of the skin induces photo damage and generates cytotoxic intracellular reactive oxygen species (ROS), activating the unfolded protein response (UPR) to adapt or reduce these UVB-mediated damages. We previously identified a role for the key UPR mediator inositol requiring enzyme 1 (IRE1α) in the UV-DNA damage response. Here, we show that in the absence of IRE1α, PERK activity and protein levels are significantly compromised following UVB irradiation. Additionally, the loss of IRE1α suppressed phosphorylation of the PERK target, nuclear factor erythroid-2-related factor 2 (NRF2), and NRF2-dependent antioxidant gene expression after UVB irradiation. Interestingly, IRE1α-deficient keratinocytes exhibit elevated basal ROS levels, while a robust ROS induction upon UVB exposure is abolished. Because UVB-induced ROS plays an essential role in regulating skin inflammation, we analyzed recruited immune cell populations and the expression of pro-inflammatory cytokines, Il-6 and Tnfα in mice with epidermally-targeted deletion of Ire1α. Following UVB irradiation, there was significantly less recruitment of neutrophils and leukocytes and reduced expression of pro-inflammatory cytokine genes in the skin of mice lacking IRE1α. Furthermore, keratinocyte proliferation was also significantly reduced after chronic UVB exposure in the skin of these mice. Collectively, our findings indicate that IRE1α is essential for basal and UVB-induced oxidative stress response, UV-induced skin immune responses, and keratinocyte proliferation. These findings shed new light on the protective function of IRE1α in the response to UV.

Antioxidative and Anti-photooxidative Potential of Interruptins from the Edible Fern Cyclosorus terminans in Human Skin Cells.

<p>Background: Human skin is exposed daily to oxidative stress factors such as UV light, chemical pollutants, and invading organisms. Reactive oxygen species (ROS) are intermediate molecules that cause cellular oxidative stress. In order to survive in an oxygen-rich environment, all aerobic organisms, including mammals, have evolved enzymatic and non-enzymatic defence systems. The interruptins from an edible fern Cyclosorus terminans possess antioxidative properties and can scavenge intracellular ROS in adipose-derived stem cells. <p> Objectives: This study aimed to evaluate the antioxidative efficacy of interruptins A, B, and C in cultured human dermal fibroblasts (HDFs) and epidermal keratinocytes (HEKs). Moreover, the anti-photooxidative activity of interruptins in ultraviolet (UV)-exposed skin cells was investigated. <p> Methods: The intracellular ROS scavenging capacity of interruptins in skin cells was measured by flow cytometry. Their induction effects on gene expression of the endogenous antioxidant enzymes was monitored using real-time polymerase chain reaction. <p> Results: Interruptins A and B, but not interruptin C, were highly effective in ROS scavenging, particularly in HDFs. Interruptins A and B upregulated gene expression of superoxide dismutase (SOD)1, SOD2, catalase (CAT), and glutathione peroxidase (GPx) in HEKs, but they only induced SOD1, SOD2, and GPx gene expression in HDFs. Additionally, interruptins A and B efficiently suppressed UVA- and UVB-induced ROS generation in both HEKs and HDFs. <p> Conclusion: The results suggest that these naturally occurring interruptins A and B are potent natural antioxidants and therefore may have the potential in the future of inclusion in antiaging cosmeceutical products.</p>.

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.

Peroxiredoxin V Protects against UVB-Induced Damage of Keratinocytes.

Ultraviolet B (UVB) irradiation generates reactive oxygen species (ROS), which can damage exposed skin cells. Mitochondria and NADPH oxidase are the two principal producers of ROS in UVB-irradiated keratinocytes. Peroxiredoxin V (PrxV) is a mitochondrial and cytosolic cysteine-dependent peroxidase enzyme that robustly removes H2O2. We investigated PrxV's role in protecting epidermal keratinocytes against UVB-induced ROS damage. We separated mitochondrial and cytosolic H2O2 levels from other types of ROS using fluorescent H2O2 indicators. Upon UVB irradiation, PrxV-knockdown HaCaT human keratinocytes showed higher levels of mitochondrial and cytosolic H2O2 than PrxV-expressing controls. PrxV depletion enhanced hyperoxidation-mediated inactivation of mitochondrial PrxIII and cytosolic PrxI and PrxII in UVB-irradiated keratinocytes. PrxV-depleted keratinocytes exhibited mitochondrial dysfunction and were more susceptible to apoptosis through decreased oxygen consumption rate, loss of mitochondrial membrane potential, cardiolipin oxidation, cytochrome C release, and caspase activation. Our findings show that PrxV serves to protect epidermal keratinocytes from UVB-induced damage such as mitochondrial dysfunction and apoptosis, not only by directly removing mitochondrial and cytosolic H2O2 but also by indirectly improving the catalytic activity of mitochondrial PrxIII and cytosolic PrxI and PrxII. It is possible that strengthening PrxV defenses could aid in preventing UVB-induced skin damage.

Protective Effect of Betula Platyphylla on Ultraviolet B-irradiated HaCaT Keratinocytes

Objectives: Betula Platyphylla(BP) has been used as a analgesic, anti-microbial, anti-oxidant drug in Eastern Asia. However, it is still unknown whether BP ethanol extract could exhibit the inhibitory activities against ultraviolet B(UVB)-induced skin injury on human keratinocytes, HaCaT cells. This study was aimed to investigate the protective activity of BP ethanol extract on UVB-irradiated skin injury in HaCaT cells.Methods: The skin injury model of HaCaT cells was established under UVB stimulation. HaCaT keratinocyte cells were pre-treated with BP ethanol extract for 1 h, and then stimulated with UVB. Then, the cells were harvested to measure the cell viability, production of reactive oxygen species(ROS), pro-inflammatory cytokines such as interleukin(IL) 1-beta, IL-6, and tumor necrosis factor(TNF)-&lt;i&gt;α&lt;/i&gt;, hyaluronidase, type 1 collagen, matrix metalloproteinase(MMP)s. In addition, we examined the mitogen activated protein kinases(MAPKs) and inhibitory kappa B alpha(I&lt;i&gt;κ&lt;/i&gt;-B&lt;i&gt;α&lt;/i&gt;) as inhibitory mechanisms of BP ethanol extract.Results: The treatment of BP ethanol extract inhibited the UVBinduced cell death and ROS production in HaCaT cells. BP ethanol extract treatment inhibited the UVB-induced increase of IL-1beta, IL-6, and TNF-&lt;i&gt;α&lt;/i&gt;. BP ethanol extract treatment inhibited the increase of hyaluronidase, MMP and decrease of collagen. BP ethanol extract treatment inhibited the activation of MAPKs and the degradation of I&lt;i&gt;κ&lt;/i&gt;-B&lt;i&gt;α&lt;/i&gt;.Conclusions: Our result suggest that treatment of BP ethanol extract could inhibit the UVB-induced skin injury via deactivation of MAPKs and nuclear factor kappa B(NF-κB) in HaCaT cells. This study could suggest that BP ethanol extract could be a beneficial agent to prevent skin damage or inflammation.

Amaryllidaceae alkaloids in skin cancer management: Photoprotective effect on human keratinocytes and anti-proliferative activity in melanoma cells.

Skin cancer has high rates of mortality and therapeutic failure. In this study, to develop a multi-agent strategy for skin cancer management, the selective cytotoxicity of several alkaloid fractions and pure alkaloids isolated from Amaryllidaceae species was evaluated in melanoma cells. In addition, UVB-stimulated keratinocytes (HaCaT) were exposed to seven alkaloid fractions characterized by GC-MS, and the production of intracellular reactive oxygen species (ROS) and IL-6, were measured to evaluate their photoprotection effects. The Eucharis caucana (bulb) alkaloid fraction (20 μg/ml) had a clear effect on the viability of melanoma cells, reducing it by 45.7% without affecting healthy keratinocytes. This alkaloid fraction and tazettine (both at 2.5 μg/ml) suppressed UVB-induced ROS production by 31.6% and 29.4%, respectively. The highest anti-inflammatory potential was shown by the Zephyranthes carinata (bulb) alkaloid fraction (10 μg/ml), which reduced IL-6 production by 90.8%. According to the chemometric analysis, lycoramine and tazettine had a photoprotective effect on the UVB-exposed HaCaT cells, attenuating the production of ROS and IL-6. These results suggest that Amaryllidaceae alkaloids have photoprotective and therapeutic potential in skin cancer management, especially at low concentrations.

Targeted Knockdown of Macrophage Migration Inhibitory Factor Enhances UVB Irradiation-Induced Apoptosis Via Increasing ROS Generation in Oral Squamous Cell Carcinoma.

Objectives: We investigated the effects of macrophage migration inhibitory factor (MIF) knockdown or overexpression combined with ultraviolet radiation B (UVB) irradiation on cell proliferation and apoptosis of oral squamous cell carcinoma (OSCC). Methods: MIF expression in OSCC and adjacent tissues was detected by immunohistochemistry. MIF expression in human immortalized oral epithelial cells (HIOEC) and OSCC cells was detected by western blotting. MIF was knocked down or overexpressed in OSCC cell lines (SCC-25 and CAL-27). OSCC cells were set up into control (CON), MIF overexpression/knockdown (oeMIF/shMIF), CON + UVB, and oeMIF + UVB/shMIF + UVB groups based on their exposure to UVB irradiation. Cell line proliferation was studied using a cell counting kit-8 (CCK-8) and colony formation assays. Flow cytometry was applied for determination of apoptosis, cell cycle, reactive oxygen species (ROS) abundance, and mitochondrial membrane potential. Apoptosis-related proteins were assayed by western blotting. Results: The expression of MIF was significantly higher in OSCC tissues and cell lines than in adjacent tissues and HIOEC. MIF knockdown accompanied by UVB irradiation significantly hampered cell viability and proliferation compared to MIF knockdown or UVB irradiation alone. Western blotting and flow cytometry showed that MIF knockdown combined with UVB irradiation not only induced apoptosis via the mitochondrial pathway but also mediated the cell cycle. Flow cytometry showed that ROS and mitochondrial membrane potential depolarization were increased in the combination treatment groups compared with the mono-treatment groups. Additionally, the ROS scavenger N-acetylcysteine significantly attenuated MIF knockdown combined with UVB irradiation-induced apoptosis and reversed MIF knockdown combined with UVB irradiation-induced MAPK activation. Conclusion: MIF knockdown combined with UVB irradiation significantly inhibited the proliferation of OSCC cells. MIF was involved in UVB-induced ROS generation and enhanced UVB irradiation-induced mitochondria-dependent apoptosis of OSCC cells by activating the MAPK pathway. This suggests that MIF-targeted therapy combined with UVB irradiation may be a novel approach for treating OSCC.

Kaempferide Prevents Photoaging of Ultraviolet-B Irradiated NIH-3T3 Cells and Mouse Skin via Regulating the Reactive Oxygen Species-Mediated Signalings.

Kaempferide (KFD) is a naturally occurring flavonoid that exists in various medicinal plants. The pharmaceutical properties of KFD, including its anti-cancer, antioxidant and anti-diabetic effects, have been noted, but the effects of KFD on photoaging and their underlying molecular mechanism have yet to be elucidated. In this study, we investigated the effects of KFD on Ultraviolet-B (UVB)-mediated photoaging processes using in vitro and in vivo photoaging model systems. The topical administration of KFD on mouse dorsal areas suppressed UVB-mediated wrinkle formation and epidermal thickening. In addition, the UVB-mediated reduction of dermal collagen content, which was estimated by Masson's trichrome staining, was recovered through KFD treatments. Furthermore, we found that UVB-induced abnormal values of procollagen type-1 (COL1A1), metalloproteinases (MMP-1a and MMP-3) and proinflammatory cytokines (IL-8, MCP-3 and IL-6) on mouse skin tissue as well as NIH-3T3 cells was recovered through KFD treatment. The administration of KFD to NIH-3T3 cells suppressed the UVB-mediated upregulation of reactive oxygen species (ROS), mitogen-activated protein kinases (MAPKs) and AKT phosphorylation. Furthermore, the treatment of ROS inhibitor restored the UVB-induced MAPKs and AKT phosphorylation as well as the abnormal expression of photoaging related genes. These findings indicate that KFD can attenuate UVB-induced ROS elevation to elicit anti-photoaging activity. Taken together, our data suggest that KFD could be developed as a potential natural anti-photoaging agent.

REDD1 interacts with AIF and regulates mitochondrial reactive oxygen species generation in the keratinocyte response to UVB

Non-melanoma skin cancer (NMSC) incidence is rising, especially in high-risk, immunocompromised groups such as organ transplant patients, who often develop numerous, aggressive cutaneous squamous cell carcinomas. Identifying the pathways that support NMSC development will result in new approaches for prevention and therapy. Our goal is to define the function of REDD1 (Regulated in DNA Damage and Development 1) in the UVB stress response. REDD1 is rapidly induced by a variety of stressors to repress mechanistic target of rapamycin complex I (mTORC1), and it has been reported that REDD1 loss causes dysfunctional mitochondria with increased reactive oxygen species (ROS) and impaired oxidative phosphorylation (OXPHOS). We now show that knockout of REDD1 in human keratinocytes sensitizes them to UVB-induced apoptosis in an mTORC1-independent manner and intensifies mitochondrial ROS generation. Upon REDD1 knockout, we observe reduced levels of apoptosis inducing factor (AIF), a mitochondrial intermembrane space NADH oxidase that is required for electron transport chain Complex I biogenesis. Further, we show that keratinocyte REDD1 interacts with both AIF and the mitochondrial import protein CHCHD4, a direct binding partner of AIF that ensures functional OXPHOS. Our results support the hypothesis that REDD1 is part of a mitochondrial complex that protects cells from UVB-induced ROS toxicity and suggest novel therapeutic targets for prevention and therapy of NMSC.

HSP27 Protects Skin From Ultraviolet B -Induced Photodamage by Regulating Autophagy and Reactive Oxygen Species Production.

Ultraviolet (UV) irradiation has been well documented to be linked with almost all skin problems we know, and both dermis and epidermis may be affected to varying degrees by UV irradiation. Every time when exposed to sunlight without protection, our skin will step closer to photoaging, leading to irreversible consequences ultimately. Heat shock protein 27 (HSP27) is a vital protein involved in cell growth, autophagy, apoptosis, drug resistance, tumor genesis and metastasis. Evidence suggests that the organism is subjected to various internal and external environmental stresses (heat, oxidative stress, organic toxicants, etc.), and HSP27 with high expression has protective function. However, the expression of HSP27 in coping with UV irradiation have not been examined thoroughly. In this study, photodamage models were developed through different doses of UVB irradiation in human epidermal keratinocytes (HEKs) (30 mJ/cm2), human dermal fibroblasts (HDFs) (150 mJ/cm2) and mouse skin (2,700 mJ/cm2). HSP27 knockdown decreased cell viability and increased the incidence of UVB-induced reactive oxygen species (ROS) production. We got consistent results in vivo and vitro. Compared with that in the UVB group, the expression of LC3B was significantly lower, while the expression of p62 was significantly higher in the UVB + si-HSP27 group. It was also revealed that HSP27 knockdown reduced the expressions of some antioxidants, such as superoxide dismutase (SOD) and catalase (CAT), which accelerated UVB-induced ROS release. Moreover, histological results showed that epidermis was thickened and collagen fibers were disorganized in the UVB + si-HSP27 group. These findings have demonstrated that HSP27 might play a photoprotective role in the UVB-induced skin damage process by maintaining the normal autophagy and antioxidant level. It is implied that HSP27 could be a potential therapeutic target of photodamage. However, determination of the definitive mechanism requires further exploration.

Anti-photoaging effects of flexible nanoliposomes encapsulated Moringa oleifera Lam. isothiocyanate in UVB-induced cell damage in HaCaT cells

Skin photoaging is premature skin aging damage that occurs after repeated exposure to ultraviolet (UV) radiation. Although isothiocyanates extracted from the moringa tree (Moringa oleifera Lam.) (MITC) exhibit excellent effects against skin photoaging, its application is restricted because of its characteristics, such as extremely low water solubility, bioavailability, and easy degradation. Currently, flexible nanoliposomes have gained increasing interest as a biocompatible polymer for applications such as transdermal drug delivery. We prepare amphiphilic hyaluronic acid (HA) conjugated with ceramide (CE) to modify nanoliposomes for MITC (HACE/MITC NPs) delivery. The HACE/MITC nanoparticles (NPs) are prepared and characterized for entrapment efficiency, particle size, polydispersity index, zeta potential, in vitro release, in vivo skin permeation, and in vitro protective effect of photoaging. The zeta potential of MITC NPs and HACE/MITC NPs is −24.46 mV and −24.93 mV, respectively. After modification of HACE, the entrapment efficient of MITC liposome increased from 62.54% to 70.67%, and the particle size decreased from 266.1 nm to 192.8 nm. In vivo skin permeation, permeated drug increased from 49.42 to 71.40%. Moreover, the results showed that the entrapment of MITC in nanoliposomes improves its stability, efficacy, and skin permeation. Further, HACE/MITC NPs are favorable for uptake by HaCaT cells without requiring changes in cell morphology, which significantly improves the activities of antioxidant enzymes, scavenges UVB-induced reactive oxygen species, protects skin from damage, and reduces MMP-1, MMP-3, and MMP-9 expression caused by radiation-induced photoaging. Our results strongly suggest that flexible nanoliposomes successfully improved the cell membrane permeation of MITC, and that anti-photoaging and HACE/MITC NPs can potentially be used as candidates for photoaging therapy.

Irradiation with 590-nm yellow light-emitting diode light attenuates oxidative stress and modulates UVB-induced change of dermal fibroblasts.

Recently, light-emitting diode (LED)-based devices have emerged as effective and safe tools for the treatment of photoaged skin. However, few studies have been conducted to elucidate the underlying mechanism behind the effect on photoageing of LED light. In this study, we induced photoageing of human dermal fibroblasts (HDFs) with Ultraviolet B (UVB) irradiation and evaluated the ability of 590-nm LED radiation to induce recovery from oxidative stress, restore collagen formation and regulate inflammatory changes. Photoageing was induced in cultured human dermal fibroblasts (HDFs) using UVB irradiation of 50mJ/cm2 . Then, the photoaged HDFs were irradiated with LED using a custom-built 590-nm LED device which emits light with an intensity of 38mW/cm2 (irradiated for 900s with 34.2J/cm2 of total energy). LED irradiation significantly attenuated UVB-induced reactive oxygen species generation and UVB-induced phosphorylation of JNK, c-Fos and c-Jun. In addition, the procollagen levels were recovered significantly, and MMP-9 levels were significantly suppressed after LED irradiation. The UVB-induced phosphorylation levels of NF-κB and pro-inflammatory enzyme COX-2 also significantly decreased. Our results suggest that 590-nm yellow light irradiation may be an effective and safe anti-oxidative and anti-inflammatory treatment modality for photoaged skin.

Astaxanthin Protects Ultraviolet B-Induced Oxidative Stress and Apoptosis in Human Keratinocytes via Intrinsic Apoptotic Pathway.

BackgroundUltraviolet radiation causes skin damage due to increased production of reactive oxygen species (ROS) and inflammatory intermediates and direct attack of DNA of skin cells. Astaxanthin is a reddish pigment that belongs to a group of chemicals called carotenoids and has protective effects as an antioxidant.ObjectiveTo determine the beneficial effects of astaxanthin on damaged human skin after exposure to ultraviolet radiation.MethodsNormal human epidermal keratinocytes (NHEKs) were pre-treated with astaxanthin for 24 hours and exposed to ultraviolet B (UVB) irradiation. After 24 hours, the Cell Counting Kit-8 (CCK-8) assay measured cell viability, ROS assay and flow cytometry analysis assessed apoptosis, and western blotting was performed to determine expression of apoptosis-related proteins.ResultsAstaxanthin significantly inhibited UVB-induced NHEKs cytotoxicity. Pretreatment of NHEKs with astaxanthin reduced UVB-induced ROS production. Astaxanthin caused significant inhibition of UVB-induced apoptosis, as evidenced by flow cytometry analysis and western blotting.ConclusionThese results suggest that astaxanthine has a beneficial effect of reducing damage caused by UVB by effectively inhibiting cell death and reducing ROS production in keratinocytes.

Eisenia bicyclis Extract Repairs UVB-Induced Skin Photoaging In Vitro and In Vivo: Photoprotective Effects.

Chronic exposure to ultraviolet B (UVB) is a major cause of skin aging. The aim of the present study was to determine the photoprotective effect of a 30% ethanol extract of Eisenia bicyclis (Kjellman) Setchell (EEB) against UVB-induced skin aging. By treating human dermal fibroblasts (Hs68) with EEB after UVB irradiation, we found that EEB had a cytoprotective effect. EEB treatment significantly decreased UVB-induced matrix metalloproteinase-1 (MMP-1) production by suppressing the activation of mitogen-activated protein kinase (MAPK)/activator protein 1 (AP-1) signaling and enhancing the protein expression of tissue inhibitors of metalloproteinases (TIMPs). EEB was also found to recover the UVB-induced degradation of pro-collagen by upregulating Smad signaling. Moreover, EEB increased the mRNA expression of filaggrin, involucrin, and loricrin in UVB-irradiated human epidermal keratinocytes (HaCaT). EEB decreased UVB-induced reactive oxygen species (ROS) generation by upregulating glutathione peroxidase 1 (GPx1) and heme oxygenase-1 (HO-1) expression via nuclear factor erythroid-2-related factor 2 (Nrf2) activation in Hs68 cells. In a UVB-induced HR-1 hairless mouse model, the oral administration of EEB mitigated photoaging lesions including wrinkle formation, skin thickness, and skin dryness by downregulating MMP-1 production and upregulating the expression of pro-collagen type I alpha 1 chain (pro-COL1A1). Collectively, our findings revealed that EEB prevents UVB-induced skin damage by regulating MMP-1 and pro-collagen type I production through MAPK/AP-1 and Smad pathways.

Frog Skin Derived Peptides With Potential Protective Effects on Ultraviolet B-Induced Cutaneous Photodamage.

Hyla annectans is a tree frog living in the southwestern plateau area of China where there is strong ultraviolet radiation and long duration of sunshine. So their naked skin may possess chemical defense components that protect it from acute photo-damage. However, no such peptide or components has been identified till to date. In the current work, two novel peptides (FW-1, FWPLI-NH2 and FW-2, FWPMI-NH2) were identified from the skin of the tree frog. Five copies of FW-1 and four copies of FW-2 are encoded by an identical gene and released from the same protein precursor, which possess 167 amino acid residues. FW-1 and -2 can exert significant anti-inflammatory functions by directly inhibiting Ultraviolet B irradiation (UVB)-induced secretion of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). They may achieve this function by modulating the UV-induced stress signaling pathways such as Mitogen-activated protein kinases (MAPK) and Nuclear Factor Kappa B (NF-κB). Besides, FW-1 and -2 showed potential antioxidant effects on epidermis by attenuating the UVB-induced reactive oxygen species (ROS) production through an unknown mechanism. Considering small peptides’ easy production, storage, and potential photo-protective activity, FW-1/2 might be exciting leading compounds or templates for the development of novel pharmacological agents for the suppression of UVB-induced skin inflammation. Moreover, this study might expand our knowledge on skin defensive mechanism of tree frog upon UVB irradiation.

Prunus mume Seed Exhibits Inhibitory Effect on Skin Senescence via SIRT1 and MMP-1 Regulation.

The Prunus mume seed is a by-product of the food industry, and we studied its potential as a food biomaterial, particularly for nutraceutical and inner beauty products. Alternative animal tests showed that an extract of P. mume ripened seed (PmRS) was not toxic on the skin. PmRS exhibited protective effects against ultraviolet- (UV-) induced skin aging in mice, confirmed by phenotypic indications, including increased collagen levels and decreased skin thickness. Compared with the UV-saline group, the UV-PmRS group showed increased levels of silent mating type information regulation 2 homolog 1 (SIRT1) and collagen and decreased matrix metalloproteinase- (MMP-) 1 expression. The protective effect of PmRS treatment against UVB-mediated cell viability was observed in vitro without any cytotoxicity, and PmRS prevented UVB-induced reactive oxygen species generation in HaCaT cells. PmRS downregulated MMP-1 and MMP-13 compared with the UVB-irradiated group. However, mRNA expressions of tissue inhibitor of metalloproteinase-1 and SIRT1 were upregulated by PmRS treatment. MMP-1 and SIRT1 treated with PmRS were decreased and increased, respectively, at the protein level. Moreover, PmRS treatment reduced c-Jun N-terminal kinase and p38 phosphorylation compared with the UVB-treated group. We postulate that P. mume seed could be a useful ingredient in nutraceuticals and inner beauty-purpose foods.

Malonic Acid Isolated from Pinus densiflora Inhibits UVB-Induced Oxidative Stress and Inflammation in HaCaT Keratinocytes.

Skin aging is caused by exposure to various external factors. Ultraviolet B (UVB) irradiation induces oxidative stress, photoaging, and inflammation in skin cells. Pinus densiflora Sieb. et Zucc. (red pine) has various antimicrobial and antioxidant activities. However, the anti-inflammatory effects of red pine on skin have rarely been reported. The protective effects of malonic acid (MA) isolated from Pinus densiflora were investigated against UVB-induced damage in an immortalized human keratinocyte cell line (HaCaT). MA increased levels of the antioxidant enzymes superoxide dismutase 1 (SOD-1) and heme oxygenase 1 (HO-1) via activation of nuclear factor-erythroid 2-related factor-2 (Nrf2), resulting in a reduction in UVB-induced reactive oxygen species (ROS) levels. Additionally, the inhibition of ROS increased HaCaT cell survival rate. Thus, MA downregulated the expression of ROS-induced nuclear factor-κB, as well as inflammation-related cytokines (interleukin-6, cyclooxygenase-2, and tumor necrosis factor-α). Furthermore, MA significantly suppressed the mitogen-activated protein kinase/activator protein 1 signaling pathway and reduced the expression of matrix metalloproteinases (MMPs; MMP-1, MMP-3, and MMP-9). In contrast, MA treatment increased the expression of collagen synthesis regulatory genes (COL1A1 and COL3A1) via regulation of Smad2/3 signal induction through transforming growth factor-β. In conclusion, MA protected against UVB-induced photoaging via suppression of skin inflammation and induction of collagen biosynthesis.

Fermented black rice and blueberry with Lactobacillus plantarum MG4221 improve UVB-induced skin injury

ABSTRACTChronic ultraviolet (UV) exposure causes skin injury thorough the production of reactive oxygen species (ROS). Skin dryness, a characteristic of UV-induced injury, is closely related to skin barrier dysfunction. We investigated the effect of fermented black rice and blueberry with Lactobacillus plantarum (FBBBR) on UVB-induced skin injury. In vitro, FBBBR suppressed UVB-induced ROS generation, apoptosis, and metalloproteinase-9 expression, while increasing the expression of collagen type 1 alpha 1 (COL1A1) gene and natural moisturising factor-related genes such as filaggrin (FLG) and transglutaminase-1 (TGM-1). Oral administration of FBBBR increased serum catalase activity and decreased serum IgE levels, improved stratum corneum hydration and epidermal thickness and enhanced FLG, TGM-1, involucrin, and COL1A1 mRNA expression in dorsal skin in UVB-irradiated hairless mice. Therefore, we suggest that FBBBR can be used as a functional food with beneficial effects on skin hydration and skin barrier function.

Metformin effect on driving cell survival pathway through inhibition of UVB-induced ROS formation in human keratinocytes

Human skin functions go beyond serving only as a mechanical barrier. As a complex organ, the skin is capable to cope with external stressors cutaneous by neuroendocrine systems to control homeostasis. However, constant skin exposure to ultraviolet (UV) radiation causes progressive damage to cellular skin constituents, mainly due excessive reactive oxygen species (ROS) production. The present study shows new approaches of metformin (MET) as an antioxidant agent. Currently, MET is the first line treatment of type 2 diabetes and has attracted attention, based on its broad mechanism of action. Therefore, we evaluated MET antioxidant potential in cell-free systems and in UVB irradiated human keratinocyte HaCaT cells. In cell-free system assays MET did not show intrinsic scavenging activity on DPPH radicals or superoxide (O2−) xanthine/luminol/xanthine oxidase-generated. Cell-based results demonstrated that MET was able to reduce UVB-induced intracellular ROS and NADPH oxidase-dependent superoxide (O2−) production. MET posttreatment of HaCaT cells reduced ERK 1/2 phosphorylation, NADPH oxidase activity, and cell death by apoptosis. These findings suggest that the protection mechanism of MET may be through the inhibition of ROS formation enzyme. These results showed that MET might be a promising antioxidant agent against UV radiation induced skin damage.

Exosomes from adipose-derived stem cells attenuate UVB-induced apoptosis, ROS, and the Ca2+ level in HLEC cells

Cartilage acid protein 1 (CRTAC1) encodes a protein containing the Ca2+binding domain, which can promote apoptosis of human lens epithelial cells (HLECs) induced by ultraviolet B radiation. Exosomes secreted from adipose-derived stem cells (ASC-exo) have been used to treat many diseases, but the effect of ASC-exo on cataracts has not been established. We hypothesized that ASC-exo has a therapeutic effect on cataracts by regulating CRTAC1. We established the UVB-induced injured HLECs model to test the interactions between CRTAC1 and miR-10a-5p, and the effect on the Ca2+ level and reactive oxygen species (ROS) generation in apoptotic HLECs. We found that UVB significantly increased the level of CRTAC1 expression and induced HLEC apoptosis, while ASC-exo inhibited the induction of UVB and exosome inhibitor reduced the inhibition of ASC-exo. The qRT-PCR results showed that miR-10a-5p had a low level of expression in cataract lesions, whereas CRTAC1 was highly expressed. There was a negative correlation between the expression of CRTAC1 and miR-10a-5p. ASC-exo reversed UVB-inhibited miR-10a-5p expression and miR-10a-5p negatively regulated CRTAC1. In vitro data showed that miR-10a-5p reversed UVB-induced ROS, apoptosis, and the Ca2+ level in HLECs. Overexpression of CRTAC1 reversed the induction of ASC-exo in UVB-injured HLECs, and low expression of CRTAC1 reversed the induction of miR-10a-5p inhibitor. By upregulating the level of miR-10a-5p expression and downregulating the level of CRTAC1 expression, exosomes from ASCs attenuated UVB-induced apoptosis, ROS generation, and the Ca2+ level in HLECs. Our research provides novel insight into the treatment methods and associated mechanisms underlying cataracts.