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Arctiin, a lignin isolated from Arctium lappa, exhibits a variety of biological effects, including anti-viral, anti-inflammatory, and anti-proliferative actions, in mammalian cells. In a previous study, arctiin was demonstrated to induce procollagen type I synthesis and exhibited protective effects against ultraviolet B (UVB) radiation in normal human dermal fibroblasts (nHDFs). However, the underlying molecular mechanism of arctiin-mediated collagen synthesis remains unknown. In the present study, the mechanism for increased expression of collagen type 1a 1 chain (COL1A1) mRNA in arctiin-induced nHDFs was identified. The expression of microRNA-378b (miR-378b), downregulated by arctiin, was correlated with the expression of sirtuin-6 (SIRT6) mRNA, a regulator of COL1A1 mRNA. Furthermore, it was revealed that arctiin protected the UVB radiation-mediated decrease in COL1A1 mRNA expression, through the miR-378b/SIRT6 signaling pathway. In conclusion, these results suggest that arctiin regulates COL1A1 through the miR-378b-SIRT6 axis. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) light mediates skin aging and induces destruction of the dermis by modulating the expression levels of extracellular matrix-associated genes, including collagen and matrix metalloproteinases. Sirtuin 6 (SIRT6), a member of the sirtuin family of proteins, regulates collagen metabolism and is an established anti-aging protein. However, the exact underlying mechanism by which SIRT6 expression is regulated in dermal fibroblasts during the aging process is unclear. The present study demonstrated that expression of microRNA-378b (miR-378b) is induced in UVB-exposed human dermal fibroblasts (HDFs), and this was inversely associated with the mRNA expression levels of α-1-type 1 collagen (COL1A1). In addition, knockdown of miR-378b enhanced the mRNA expression levels of COL1A1 in HDFs. A target analysis for miR-378b was performed, and the results revealed that SIRT6, a regulator of COL1A1, contains a target sequence for miR-378b in its 3'untranslated region. Notably, the present study demonstrated that an miR-378b mimic and inhibitor may directly regulate SIRT6 expression in HDFs. In conclusion, the present study suggested that miR-378b represses the mRNA expression levels of COL1A1 via interference with SIRT6 in HDFs, and may contribute to the underlying molecular mechanism by which UVB inhibits collagen I in dermal fibroblasts. [ABSTRACT FROM AUTHOR]

Anti-aging cosmetics are widely used for improving signs of aged skin such as skin wrinkles, decreased elasticity, low dermal density and yellow skin tone. The present study evaluated the effects of cosmetic formulations, eye cream and facial cream, containing palmitoyl peptides, Silybum marianum (S. marianum) seed oil, vitamin E and other functional ingredients on the improvement of facial wrinkles, elasticity, dermal density and skin tone after 4 weeks period of application on aged human skin. Healthy volunteers (n=20) with aged skin were recruited to apply the test materials facially twice per day for 4 weeks. Skin wrinkles, elasticity, dermal density and skin tone were measured instrumentally for assessing the improvement of skin aging. All the measurements were conducted prior to the application of test materials and at 2 and 4 weeks of treatment. Crow's feet wrinkles were decreased 5.97% after 2 weeks of test material application and 14.07% after 4 weeks of application in comparison of pre-application. Skin elasticity was increased 6.81% after 2 weeks and 8.79% after 4 weeks. Dermal density was increased 16.74% after 2 weeks and 27.63% after 4 weeks. With the L* value indicating skin brightness and the a* value indicating erythema (redness), the results showed that brightness was increased 1.70% after 2 weeks and 2.14% after 4 weeks, and erythema was decreased 10.45% after 2 weeks and 22.39% after 4 weeks. Hence, the test materials appear to exert some degree of anti-aging effects on aged human skin. There were no abnormal skin responses from the participants during the trial period. We conclude that the facial and eye cream containing palmitoyl peptides and S. marianum seed oil, vitamin E and other ingredients have effects on the improvement of facial wrinkles, elasticity, dermal density and skin tone. [ABSTRACT FROM AUTHOR]

Dermal papilla (DP) cells function as important regulators of the hair growth cycle. The loss of these cells is a primary cause of diseases characterized by hair loss, including alopecia, and evidence has revealed significantly increased levels of reactive oxygen species (ROS) in hair tissue and DP cells in the balding population. In the present study, troxerutin, a flavonoid derivative of rutin, was demonstrated to have a protective effect against H2O2-mediated cellular damage in human DP (HDP) cells. Biochemical assays revealed that pretreatment with troxerutin exerted a protective effect against H2O2-induced loss of cell viability and H2O2-induced cell death. Further experiments confirmed that troxerutin inhibited the H2O2-induced production of ROS and upregulation of senescence-associated β-galactosidase activity. Using microRNA (miRNA) microarrays, the present study identified 24 miRNAs, which were differentially expressed in the troxerutin-pretreated, H2O2-treated HDP cells. Subsequent prediction using bioinformatics analysis revealed that the altered miRNAs were functionally involved in several cell signaling pathways, including the mitogen-activated protein kinase and WNT pathways. Overall, these results indicated that ROS-mediated cellular damage was inhibited by troxerutin and suggested that the use of troxerutin may be an effective approach in the treatment of alopecia. [ABSTRACT FROM AUTHOR]

Clinical evidence has demonstrated that the accumulation of 5a-dihydrotestosterone (DHT) in dermal papilla cells (DPCs) is implicated in androgenetic alopecia. Whether this accumulation in DHT may have direct cellular effects leading to androgenetic alopecia remains to be elucidated. The present study aimed to determine whether DHT affects cell growth, cell cycle arrest, cell death, senescence and the induction of reactive oxygen species (ROS), and whether these effects are mediated by microRNA (miRNA)-dependent mechanisms. The cell viability and cell cycle were determined, levels of ROS were examined and senescence-associated |3-galactosidase assays were performed in normal human DPCs (nHDPCs). Furthermore, miRNA expression profiling was performed using an miRNA microarray to determine whether changes in the expression levels of miRNA were associated with the cellular effects of DHT. The results revealed that DHT decreased cell growth by inducing cell death and G2 cell cycle arrest, and by increasing the production of ROS and senescence in the nHDPCs. In addition, 55 miRNAs were upregulated and 6 miRNAs were downregulated inthe DHT-treated nHDPCs. Bioinformatic analysis demonstrated that the putative target genes of these upregulated and down-regulated miRNAs were involved in cell growth, cell cycle arrest, cell death, senescence and the production of ROS. Specifically, the target genes of five highly upregulated and downregulated miRNAs were identified and were associated with the aforementioned effects of DHT. These results demonstrated that the expression of miRNA was altered in the DHT-treated nHDPCs and suggest the potential mechanisms of DHT-induced cell growth repression, cell cycle arrest, cell death, senescence and induction of ROS. [ABSTRACT FROM AUTHOR]

Para-phenylenediamine (PPD) is a major component of hair coloring and black henna products. Although it has been largely demonstrated that PPD induces allergic reactions and increases the risk of tumors in the kidney, liver, thyroid gland and urinary bladder, the effect on dermal papilla cells remains to be elucidated. Therefore, the current study evaluated the effects of PPD on growth, cell death and senescence using cell-based assays and microRNA (miRNA) microarray in normal human hair dermal papilla cells (nHHDPCs). Cell viability and cell cycle analyses demonstrated that PPD exhibited a significant cytotoxic effect on nHHDPCs through inducing cell death and G2 phase cell cycle arrest in a dose-dependent manner. It was additionally observed that treatment of nHHDPCs with PPD induced cellular senescence by promoting cellular oxidative stress. In addition, the results of the current study indicated that these PPD-mediated effects were involved in the alteration of miRNA expression profiles. Treatment of nHHDPCs with PPD altered the expression levels of 74 miRNAs by ≥2-fold (16 upregulated and 58 downregulated miRNAs). Further bioinformatics analysis determined that these identified miRNA target genes were likely to be involved in cell growth, cell cycle arrest, cell death, senescence and the induction of oxidative stress. In conclusion, the observations of the current study suggested that PPD was able to induce several cytotoxic effects through alteration of miRNA expression levels in nHHDPCs. [ABSTRACT FROM AUTHOR]

The effects of skin pores on skin topographic features can be reduced by decreasing excessive production and accumulation of sebum and elimination of comedones. Therefore, a cosmetic cleanser that regulates sebum homeostasis is required. In the present study, the effects of a cosmetic cleanser that contained Diospyros kaki folium, Polygonum cuspidatum and Castanea crenata var. dulcis (DPC) was examined on the removal of sebum and on skin pore size. Healthy volunteers (n=23) aged 20-50 years were asked to apply the test materials to the face. Skin oil content, pore size, pore number and extracted sebum surface area were measured using various measurement methods. All the measurements were performed at pre- and post-application of the test materials. When the cosmetic cleanser containing DPC was applied to the skin, the oil content decreased by 77.3%, from 6.19 to 1.40. The number of skin pores decreased by 24.83%, from 125.39 to 94.23. Skin pore size decreased from 0.07 to 0.02 µm³ (71.43% decrease). The amount of extracted sebum increased by 335% when the DPC cleanser was used. Compared to the control cleanser, skin oil content was significantly decreased when the cleanser that contained DPC was used. The cleanser containing DPC also decreased pore size and number. Finally, the DPC cleanser easily removed solidified sebum from the skin. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) radiation impairs intracellular functions by directly damaging DNA and by indirectly generating reactive oxygen species (ROS), which induce cell cycle arrest and apoptosis. UV radiation can also alter gene expression profiles, including those of mRNA and microRNA (miRNA). The effects of UV radiation on cellular functions and gene expression have been widely documented in human skin cells such as keratinocytes, melanocytes and dermal fibroblasts, but the effect it has on other types of skin cell such as dermal papilla cells, which are crucial in the induction of hair follicle growth, remains unknown. In the current study, the effect of UV radiation on physiological changes and miRNA-based expression profiles in normal human dermal papilla cells (nHDPs) was investigated. UVB radiation of ⩾50 mJ/cm2 displayed high cytotoxicity and apoptosis in a dose-dependent manner. In addition, ROS generation was exhibited in UVB-irradiated nHDPs. Furthermore, using miRNA microarray analysis, it was demonstrated that the expression profiles of 42 miRNAs in UVB-irradiated nHDPs were significantly altered compared with those in the controls (35 upregulated and 7 downregulated). The biological functions of the differentially expressed miRNAs were studied with gene ontology analysis to identify their putative target mRNAs, and were demonstrated to be involved in cell survival- and death-related functions. Overall, the results of the present study provide evidence that miRNA-based cellular mechanisms may be involved in the UVB-induced cellular response in nHDPs. [ABSTRACT FROM AUTHOR]

Human keratinocytes are located in the outermost skin layer and thus particularly vulnerable to ultraviolet B (UVB) radiation exposure. Previous studies have focused on the cellular and molecular perspectives of UVB-induced keratinocyte damage. In the present study, it was demonstrated that pretreatment with the phytochemical arctiin, one of the lignin compounds, protects human HaCaT keratinocytes from UVB-mediated damage. Biochemical assays revealed that UVB-induced cytotoxicity and cell death were significantly reduced in arctiin-pretreated HaCaT cells. In addition, arctiin promoted the wound healing and DNA repair properties of keratinocytes. The photoprotective effects of arctiin were associated with changes in the expression levels of specific microRNAs (miRNAs) in HaCaT cells. A bioinformatics analysis demonstrated that the miRNAs were functionally involved in cancer, cell cycle, and Wnt and mitogen-activated protein kinase signaling pathways. In the present study, the results from the cellular and molecular assays demonstrated a novel role for arctiin in UVB protection in keratinocytes, which is mediated by miRNA responses and the suppression of UVB-induced cell death. Furthermore, arctiin is implicated as a potential chemopreventive agent through UVB protection of keratinocytes. [ABSTRACT FROM AUTHOR]

Melanogenesis is the process of generating pigmentation via melanin synthesis and delivery. Three key enzymes, tyrosinase, tyrosinase-related protein 1 (TRP1) and TRP2, metabolize melanin from L-tyrosine. Melanin synthesizing enzymes are regulated by microphthalmia-associated transcription factor (MITF). The titrated extract of Centella asiatica (TECA) contains the major components asiatic acid, asiaticoside and madecassic acid. The present study revealed that TECA reduces the melanin content in melanocytes. Moreover, the asiaticoside contained in TECA modulated melanogenesis by inhibiting tyrosinase mRNA expression. The decrease in tyrosinase mRNA levels was mediated through MITF. Uniquely, asiaticoside inhibited MITF by decreasing its DNA binding affinity. In conclusion, the results of the present study indicate that asiaticoside treatment may have beneficial effects in hyperpigmentation diseases or for skin whitening. [ABSTRACT FROM AUTHOR]

microRNAs (miRNAs) are small non-coding RNAs that regulate various biological processes by interfering with the translation of target genes. Several studies have suggested that miRNAs are involved in cellular responses to hydrogen peroxide (H2O2). Reactive oxygen species (ROS) are involved in hair malignancies, however, the H2O2-induced, miRNA-dependent regulatory mechanisms of human dermal papilla (HDP) cells are not fully understood. Our previous study demonstrated that changes in miRNA expression function to regulate growth arrest and apoptosis in UVB-irradiated HDPs. In the present study, miRNA expression was profiled in HDPs treated with H2O2. The transcriptome analysis of H2O2-treated HDPs enabled the identification of 68 differentially expressed miRNAs (62 were upregulated and 6 were downregulated) and 14,316 putative target genes of the miRNAs. Gene ontology (GO) analysis was utilized to verify that the putative target genes of the altered miRNAs were associated with H2O2-induced cell growth arrest and apoptosis. This bioinformatics analysis indicated that H2O2-response pathways involved in growth arrest and apoptosis were significantly affected. The identification of miRNAs and their putative targets may offer new therapeutic strategies for H2O2-induced hair follicle disorders. [ABSTRACT FROM AUTHOR]