Search

• DNA methyltransferase 1 (DNMT1) is implicated in epigenetic skin aging. • DVP modulated DNMT1 and extracellular matrix in vitro and in vivo. • Skin anti-aging epigenetic mechanism of DVP was revealed. • Potential of DNMT1 inhibitors as skin anti-aging agents was validated. [ABSTRACT FROM AUTHOR]

• Ultraviolet (UV) irradiation is the main contributing factor for skin aging. • UV treatment decreases the expression of HDACs and SIRTs in dermal fibroblasts. • HDAC4 may regulate MMP-1 and type I procollagen expression through the activation of JNK pathways. Ultraviolet (UV) irradiation is the main contributing factor for skin aging. UV irradiation induces epigenetic changes in skin. It increases the activity of histone acetylases (HATs) but decreases that of histone deacetylases (HDACs). We aimed to investigate alterations in all classes of HDACs and sirtuins (SIRTs) in response to UV irradiation, and determine the HDACs regulating the expressions of matrix metalloproteinase 1 (MMP-1) and type I procollagen. Primary human dermal fibroblasts were UV irradiated. HDAC4 was knocked-down or overexpressed to investigate its effect on the expression of MMP-1 and type I procollagen. The mRNA and protein levels were analyzed by quantitative real-time polymerase chain reaction and western blotting. Among 11 HDACs and 7 SIRTs, we found that the expression of HDAC4, HDAC5, HDAC6, HDAC7, HDAC8, HDAC11, SIRT2, and SIRT3 were significantly and consistently reduced by UV at both mRNA and protein levels. Among these, the reduction of HDAC4 was responsible for the basal and UV-induced increase in the expression of MMP-1 and decrease in that of type I procollagen. Furthermore, the reduced HDAC4 could activate c-Jun N-terminal kinase (JNK), resulting in an increase in MMP-1 and decrease in type I procollagen. UV treatment decreases the expression of HDACs and SIRTs in dermal fibroblasts; in particular, the UV-induced reduction in the expression of HDAC4 might play an important role in regulating the expression of MMP-1 and type I procollagen. [ABSTRACT FROM AUTHOR]

Peroxisome proliferator-activated receptor alpha (PPARα) is a nuclear hormone receptor involved in the transcriptional regulation of lipid metabolism, fatty acid oxidation, and glucose homeostasis. Its activation stimulates antioxidant enzymes such as catalase, whose expression is decreased in aged human skin. Here we investigated the expression of PPARα in aged and ultraviolet (UV)-irradiated skin, and whether PPARα activation can modulate expressions of matrix metalloproteinase (MMP)-1 and procollagen through catalase regulation. We found that PPARα mRNA level was significantly decreased in intrinsically aged and photoaged human skin as well as in UV-irradiated skin. A PPARα activator, Wy14643, inhibited UV-induced increase of MMP-1 and decrease of procollagen expression and caused marked increase in catalase expression. Furthermore, production of reactive oxygen species (ROS) was suppressed by Wy14643 in UV-irradiated and aged dermal fibroblasts, suggesting that the PPARα activation-induced upregulation of catalase leads to scavenging of ROS produced due to UV irradiation or aging. PPARα knockdown decreased catalase expression and abolished the beneficial effects of Wy14643. Topical application of Wy14643 on hairless mice restored catalase activity and prevented MMP-13 and inflammatory responses in skin. Our findings indicate that PPARα activation triggers catalase expression and ROS scavenging, thereby protecting skin from UV-induced damage and intrinsic aging. [ABSTRACT FROM AUTHOR]

• Ultraviolet radiation induced EZH2 expression in human skin and human dermal fibroblasts. • EZH2 promoted MMP-1 expression but suppressed type I procollagen expression in human dermal fibroblasts. • EZH2 interacted with the NF-κB components p65 and p50 at the MMP-1 promoter to regulate MMP-1 transcriptional activation. • EZH2 interacted with DNMT1 and H3K27me3 at the COL1A2 promoter, leading to decreased COL1A2 transcription following UV irradiation. Abnormalities in the extracellular matrix (ECM) caused by ultraviolet (UV) radiation are mediated by epigenetic mechanisms. Enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase that is implicated in inflammation, immune regulation, and senescence. However, its role in controlling UV-induced ECM alterations in the skin remains elusive. Here, we investigated the role of EZH2 in UV-induced expression of matrix metalloproteinase (MMP)-1 and type I procollagen. We found that UV induced EZH2 expression in human skin in vivo and in human dermal fibroblasts (HDFs). EZH2 knockdown reduced the expression and promoter activity of MMP-1 and increased those of type I procollagen, whereas EZH2 overexpression had the opposite effects. Mechanistically, EZH2 increased NF-κB activity, and p65 and p50 expression and promoter activity. Intriguingly, chromatin immunoprecipitation assays revealed that the EZH2/p65/p50 complex was recruited and bound to the MMP-1 promoter after UV irradiation, independent of its histone methyltransferase activity. In contrast, EZH2-induced DNA methyltransferase 1 (DNMT1) formed a complex with EZH2 and enhanced the enrichment of H3K27me3 on the COL1A2 promoter following UV irradiation. These findings indicate that EZH2 plays a dual role in regulating MMP-1 and type I procollagen expression and improve our understanding of how this epigenetic mechanism contributes to UV-induced skin responses and photoaging. This study shows that inhibiting EZH2 is a potential anti-aging strategy for preventing UV-induced skin aging by reducing MMP-1 expression and inducing type I procollagen expression. [Display omitted] [ABSTRACT FROM AUTHOR]

Recently, there has been much effort to find effective ingredients which can prevent or retard cutaneous skin aging after topical or systemic use. Here, we investigated the effects of the atomic hydrogen surrounded by water molecules, H(H2O)m, on acute UV-induced responses and as well as skin aging. Interestingly, we observed that H(H2O)m application to human skin prevented UV-induced erythema and DNA damage. And H(H2O)m significantly prevented UV-induced MMP-1, COX-2, IL-6 and IL-1β mRNA expressions in human skin in vivo. We found that H(H2O)m prevented UV-induced ROS generation and inhibited UV-induced MMP-1, COX-2 and IL-6 expressions, and UV-induced JNK and c-Jun phosphorylation in HaCaT cells. Next, we investigated the effects of H(H2O)m on intrinsically aged or photoaged skin of elderly subjects. In intrinsically aged skin, H(H2O)m application significantly reduced constitutive expressions of MMP-1, IL-6, and IL-1β mRNA. Additionally, H(H2O)m significantly increased procollagen mRNA and also decreased MMP-1 and IL-6 mRNA expressions in photoaged facial skin. These results demonstrated that local application of H(H2O)m may prevent UV-induced skin inflammation and can modulate intrinsic skin aging and photoaging processes. Therefore, we suggest that modifying the atmospheric gas environment within a room may be a new way to regulate skin functions or skin aging. [ABSTRACT FROM AUTHOR]

Abstract: In addition to ultraviolet radiation, human skin is also exposed to infrared radiation (IR) from natural sunlight. IR typically increases the skin temperature. This study examined whether or not heat shock-induced ROS stimulates MMPs in keratinocyte HaCaT cells. In HaCaT cells, heat shock was found to increase the intracellular ROS levels, including hydrogen peroxide and superoxide. The heat shock treatment induced MMP-1 and MMP-9, but not MMP-2, at the mRNA and protein levels. Moreover, heat shock caused the rapid activation of the three distinct MAPKs, ERK, JNK, and p38 kinase. The heat shock-induced expression of MMP-1 and MMP-9 was significantly suppressed by a pretreatment with the antioxidant NAC or catalase. On the other hand, SOD inhibited heat shock-induced activity of MMP-9 induction, but not MMP-1. A pretreatment with NAC or catalase, but not SOD, attenuated the phosphorylation of ERK, JNK, and p38 kinase by heat shock. The potential sites of ROS generation by heat shock along with its role in the heat shock-induced expression of MMP-1 and MMP-9 were next analyzed. These results indicate that heat shock-induced ROS is promoted via NADPH oxidase, xanthine oxidase, and mitochondria. Indeed, the NADPH oxidase and xanthine oxidase activities were increased by heat shock. Overall, the ROS produced by heat shock may play an important role in the heat shock-induced activation of MAPKs, which can induce MMP-1 and-9 expressions. [Copyright &y& Elsevier]

Abstract: Two novel heptadentate ligands, pentaaza macrocycles with two pendant xpyridyl and phenol groups, were prepared and the crystal structure of the manganese(II) complex of N,N′-bis(2-pyridylmethyl)-pentaaza macrocycle revealed a pentagonal bipyramidal geometry. [Copyright &y& Elsevier]

Dehydroepiandrosterone (DHEA) and its sulfate conjugate (DHEA-S) are the most abundantly produced human adrenal steroids to be reduced with age. DHEA may be related to the process of skin aging through the regulation and degradation of extracelluar matrix protein. In this study, we demonstrate that DHEA can increase procollagen synthesis and inhibit collagen degradation by decreasing matrix metalloproteinases (MMP)-1 synthesis and increasing tisuue inhibitor of matrix metalloprotease (TIMP-1) production in cultured dermal fibroblasts. DHEA was found to inhibit ultraviolet (UV)-induced MMP-1 production and the UV-induced decrease of procollagen synthesis, probably due to the inhibition of UV-induced AP-1 activity. DHEA (5%) in ethanol:olive oil (1:2) was topically applied to buttock skin of volunteers 12 times over 4 weeks, and was found to significantly increase the expression of procollagenα1(I) mRNA and protein in both aged and young skin. On the other hand, topical DHEA significantly decreased the basal expression of MMP-1 mRNA and protein, but increased the expression of TIMP-1 protein in aged skin. We also found that DHEA induced the expressions of transforming growth factor-β1 and connective tissue growth factor mRNA in cultured fibroblasts and aged skin, which may play a role in the DHEA-induced changes of procollagen and MMP-1 expression. Our results suggest the possibility of using DHEA as an anti-skin aging agent. [ABSTRACT FROM AUTHOR]

This is a comprehensive study of the changes in major antioxidant enzymes and antioxidant molecules during intrinsic aging and photoaging processes in the epidermis and dermis of human skin in vivo . We show that the activities of superoxide dismutase and glutathione peroxidase are not changed during these processes in human skin in vivo . Interestingly, the activity of catalase was significantly increased in the epidermis of photoaged (163%) and naturally aged (118%) skin (n = 9), but it was significantly lower in the dermis of photoaged (67% of the young skin level) and naturally aged (55%) skin compared with young (n = 7) skin. The activity of glutathione reductase was significantly higher (121%) in naturally aged epidermis. The concentration of α-tocopherol was significantly lower in the epidermis of photoaged (56% of young skin level) and aged (61%) skin, but this was not found to be the case in the dermis. Ascorbic acid levels were lower in both epidermis (69% and 61%) and dermis (63% and 70%) of photoaged and naturally aged skin, respectively. Gluta thione concentrations were also lower. Uric acid did not show any significant changes. Our results suggest that the components of the antioxidant defense system in human skin are probably regulated in a complex manner during the intrinsic aging and photoaging processes. [ABSTRACT FROM AUTHOR]

Histone deacetylases (HDACs) are conserved enzymes that remove acetyl groups from lysine side chains in histones and other proteins and play a crucial role in epigenetic regulation. Previously, we showed that histone acetylation is implicated in ultraviolet (UV)-induced inflammation and matrix impairment. To elucidate the histone acetylation status and specific HDACs involved in skin aging, we examined the changes in histone acetylation, global HDAC activity, and the expression of HDACs and sirtuins (SIRTs) in intrinsically aged and photoaged human skin as well as in UV-irradiated human skin in vivo. Following acute UV irradiation, the acetylated histone H3 (AcH3) level was increased, but HDAC activity and the expression levels of HDAC4, HDAC11, and SIRT4 were significantly decreased. In intrinsically aged skin, AcH3 levels were increased, but HDAC activity and the expression levels of HDAC4, HDAC5, HDAC10, HDAC11, SIRT6, and SIRT7 were significantly decreased. However, histone acetylation and HDAC expression in photoaged skin were not significantly different from those in intrinsically aged skin. Collectively, HDAC4 and HDAC11 were decreased in both UV-irradiated and intrinsically aged skin, suggesting that they may play a universal role in increased histone acetylation associated with skin aging. [ABSTRACT FROM AUTHOR]

The skin is a unique site in the human body that has the capacity to synthesize the active form of vitamin D, 1α,25-dihydroxyvitamin D 3 (1α,25(OH) 2 D 3), from 7-dehydrocholesterol (7DHC) upon UV irradiation. Keratinocytes express both 25-hydroxylase (CYP27A1 and CYP2R1) and 1α-hydroxylase (CYP27B1), critical enzymes involved in active vitamin D synthesis. Here, we investigated the effect of skin-derived 1α,25(OH) 2 D 3 , synthesized purely within the keratinocytes, on MMP-1 expression. Treatment of human epidermal keratinocytes with 1α,25(OH) 2 D 3, but not 7DHC or 25OHD 3 , significantly increased MMP-1 expression. UV irradiation increases 1α,25(OH) 2 D 3 levels, and ketoconazole inhibits UV-induced production of 1α,25(OH) 2 D 3. Upregulation of MMP-1 by UV was reversed by inhibition of 1α,25(OH) 2 D 3 synthesis using ketoconazole or CYP27B1 siRNA. In keratinocytes, 7DHC is a substrate for both cholesterol and 1α,25(OH) 2 D 3 synthesis. We demonstrated that UV irradiation leads to decreased expression of DHCR7 (7-dehydrocholesterol reductase), the enzyme that converts 7DHC to cholesterol. Inhibition of DHCR7 with its inhibitor BM15766 decreased cholesterol synthesis and increased UV-induced MMP-1 expression, which was attenuated by ketoconazole. These findings suggest that UV-induced reduction of DHCR7 leads to a decrease in cholesterol synthesis, thereby increasing 7DHC availability for 1α,25(OH) 2 D 3 production, which enhances MMP-1 expression. Finally, UV irradiation in human skin in vivo significantly increased CYP27B1 mRNA and decreased DHCR7 mRNA expression. Taken together, we demonstrate here that skin-derived 1α,25(OH) 2 D 3 significantly increases MMP-1 expression in human keratinocytes, a previously unappreciated function of 1α,25(OH) 2 D 3. Moreover, UV irradiation upregulates the enzyme CYP27B1, which leads to 1α,25(OH) 2 D 3 synthesis, but downregulates the cholesterol-producing enzyme DHCR7, both of which collectively lead to increased MMP-1 expression in human keratinocytes. This pathway may be exploited to develop a novel cutaneous anti-aging agent that blocks local cutaneous 1α,25(OH) 2 D 3 synthesis. [ABSTRACT FROM AUTHOR]

Background Ultraviolet (UV) radiation has been reported to influence epigenetic regulation by affecting the expression of genome regulators such as DNA methyltransferase 1 (DNMT1). DNMT1 is a “gene silencer,” that is responsible for the maintenance of DNA methylation and contribution to de novo methylation. Implications of DNMT1′s involvement in the expression of UV-induced proteins have been previously reported. Objective To investigate for changes in DNA methylation-associated gene expressions by UV and to analyze the role of DNA methylation in the suppression of TIMP2 in UV-irradiated human skin. Methods The expression of DNA methylation-associated proteins and TIMP2 were analyzed in UV-irradiated human skin in vivo and in human dermal fibroblasts in vitro . To investigate the relationship between DNMT1 and TIMP2, we assessed the effect of DNMT1 knockdown, inhibition and overexpression on TIMP2 levels in human dermal fibroblasts. Lastly, methylation-specific PCR was used to confirm increased DNA methylation in TIMP2 promoter in response to UV. Results DNMT1 expression significantly increased whereas TIMP2 expression decreased in UV-irradiated human skin in vivo and in vitro . Downregulation of DNMT1 by knockdown or inhibition resulted in increased TIMP2 expression, whereas the overexpression of DNMT1 resulted in decreased TIMP2 expression. Lastly, methylation-specific PCR confirmed increased methylation on the CpG island residing in TIMP2 promoter in UV-irradiated human dermal fibroblasts. Conclusion These findings suggest that UV-induced expression of DNMT1 may be responsible for mediating DNA hypermethylation in TIMP2, and thus, silencing its expression, in UV-exposed human skin. [ABSTRACT FROM AUTHOR]

Abstract: Background: Thrombospondin-1 (TSP-1) is a matricellular glycoprotein and recognized as an inhibitor of angiogenesis and an activator of transforming growth factor-β (TGF-β). Although TSP-1 expression has been shown to be regulated by various stimuli including UV in some types of cell, more work need to be done to understand the regulation of TSP-1 expression and its functional significances in many other types of cell. Objective: In this study, we investigated the effect of UV on TSP-1 expression in human skin dermis and dermal fibroblasts and the role of TSP-1 on the type I procollagen expression after UV exposure. Methods: Human buttock skin and human dermal fibroblasts were irradiated with UV. The mRNA and the protein levels of TSP-1 or type I procollagen were measured by real-time polymerase chain reaction and Western blotting, respectively. Results: We found that UV irradiation increased TSP-1 expression at the mRNA and protein levels in human skin dermis and dermal fibroblasts. UV-induced TSP-1 expression was greatly suppressed by inhibition of the PI3K, Akt, or mTOR pathways. The inhibition of TSP-1 activity by a blocking peptide or suppression of TSP-1 expression by specific TSP-1 small interfering RNA augmented the UV-induced decrease of type I procollagen expression. Conclusion: Our results suggest that UV-induced TSP-1 plays an important role on alleviating and/or recovering the type I procollagen expression downregulated by UV in human dermal fibroblasts. [Copyright &y& Elsevier]

Proper regulation of sebum production is important for maintaining skin homeostasis in humans. However, little is known about the role of epigenetic regulation in sebocyte lipogenesis. We investigated histone acetylation changes and their role in key lipogenic gene regulation during sebocyte lipogenesis using the human sebaceous gland cell line SZ95. Sebocyte lipogenesis is associated with a significant increase in histone acetylation. Treatment with anacardic acid (AA), a p300 histone acetyltransferase inhibitor, significantly decreased the lipid droplet number and the expression of key lipogenic genes, including sterol regulatory-binding protein 1 (SREBP1), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC). In contrast, treatment with trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, increased the expression of these genes. Global HDAC enzyme activity was decreased, and HDAC1 and HDAC2 expression was downregulated during sebaceous lipogenesis. Interestingly, HDAC1 knockdown increased lipogenesis through SREBP1 induction, whereas HDAC1 overexpression decreased lipogenesis and significantly suppressed SREBP1 promoter activity. HDAC1 and SREBP1 levels were inversely correlated in human skin sebaceous glands as demonstrated in immunofluorescence images. In conclusion, HDAC1 plays a critical role in reducing SREBP1 transcription, leading to decreased sebaceous lipogenesis. Therefore, HDAC1 activation could be an effective therapeutic strategy for skin diseases related to excessive sebum production. [ABSTRACT FROM AUTHOR]

Highlights • Reflective plastic film mulches enhance the light intensity under the blueberry bush. • Reflective plastic film mulches increase the yield of blueberry. • Bioactive compounds increase by reflective plastic film mulches. • The number of flower bud on blueberry increase by reflective plastic film mulches. Abstract Reflective plastic film mulches are used in orchards to improve fruit coloration and physical properties of plant. The present study was aimed to investigate the effect of reflective plastic film mulching on photosynthetically active radiation (PAR), number of flower buds, average berry yield, total phenol content and anthocyanin content of southern highbush blueberry cv. 'O' Neal'. The mulching treatment has showed a considerable effect on PAR and PAR was consistently increased at every 20 cm of bush height from May to September. Interestingly, blueberry yield significantly increased in abundance at the time of harvesting in mulched bushes. Furthermore, total phenol and anthocyanin contents were significantly higher in fruits harvested from mulched bushes compared to control. Besides, higher numbers of flower buds were observed in mulched blueberry bushes than the non-mulched bushes. Consequently, the reflective plastic film mulching can be recommended to implement in blueberry orchards for enhance the productivity of blueberry plants. [ABSTRACT FROM AUTHOR]

Actinidia arguta, commonly known as hardy kiwifruit or baby kiwifruit has become very popular in the market due to its taste and can be eaten raw without peeling. However, characteristics of fruit development for optimal harvest date and postharvest storability of baby kiwifruit is diverse in contrast to those of green kiwifruit and yellow kiwifruit. This study was conducted to find the characteristics of fruit development for optimal harvest date and storability period post harvesting in baby kiwifruit for two years (2013–2014). The results showed that fruit weight increased showing a single sigmoid curve. The starch and sugar contents increased significantly and reached to a maximum level at 130–133 days after full bloom (DAFB) respectively. The soluble solids content (SSC) and fruit dry matter also increased and reached to a maximum stage until harvesting. Post-harvested fruits were examined after cold storability at 1 °C for 65 days. The physiochemical measurements such as SSC, fruit firmness increased with a reduction of starch content and titratable acidity (TA) at initial DAFB. However, the fruits harvested at latter stage (approx. 130–133 DAFB) after cold storability showed higher SSC content and a lower TA and fruit firmness. Moreover, the respiration rate in fruit increased till 20 days of storage and thereafter decreased slowly. This study demonstrated that quality of baby kiwifruit can be optimized through identification of ideal harvest date and by controlling storage conditions. [ABSTRACT FROM AUTHOR]

Photoaging accounts for most age-related changes in skin appearance. It has been suggested that both astaxanthin, a potent antioxidant, and collagen hydrolysate can be used as antiaging modalities in photoaged skin. However, there is no clinical study using astaxanthin combined with collagen hydrolysate. We investigated the effects of using a combination of dietary astaxanthin and collagen hydrolysate supplementation on moderately photoaged skin in humans. A total of 44 healthy subjects were recruited and treated with astaxanthin (2 mg/day) combined with collagen hydrolysate (3 g/day) or placebos, which were identical in appearance and taste to the active supplementation for 12 weeks. The elasticity and hydration properties of facial skin were evaluated using noninvasive objective devices. In addition, we also evaluated the expression of procollagen type I, fibrillin-1, matrix metalloproteinase-1 (MMP-1) and -12, and ultraviolet (UV)-induced DNA damage in artificially UV-irradiated buttock skin before and after treatment. The supplement group showed significant improvements in skin elasticity and transepidermal water loss in photoaged facial skin after 12 weeks compared with the placebo group. In the supplement group, expression of procollagen type I mRNA increased and expression of MMP-1 and -12 mRNA decreased compared with those in the placebo group. In contrast, there was no significant difference in UV-induced DNA damage between groups. These results demonstrate that dietary astaxanthin combined with collagen hydrolysate can improve elasticity and barrier integrity in photoaged human facial skin, and such treatment is well tolerated. [ABSTRACT FROM AUTHOR]