A human skin model to evaluate the protective effect of compounds against UVA damage

Role of PI3K-AKT Pathway in Ultraviolet Ray and Hydrogen Peroxide-Induced Oxidative Damage and Its Repair by Grain Ferments

UV and external environmental stimuli can cause oxidative damage to skin cells. However, the molecular mechanisms involved in cell damage have not been systematically and clearly elucidated. In our study, an RNA-seq technique was used to determine the differentially expressed genes (DEGs) of the UVA/H₂O₂-induced model. Gene Oncology (GO) clustering and the Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway analysis were performed to determine the core DEGs and key signaling pathway. The PI3K-AKT signaling pathway was selected as playing a part in the oxidative process and was verified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). We selected three kinds of Schizophyllum commune fermented actives to evaluate whether the PI3K-AKT signaling pathway also plays a role in the resistance of active substances to oxidative damage. Results indicated that DEGs were mainly enriched in five categories: external stimulus response, oxidative stress, immunity, inflammation, and skin barrier regulation. S. commune-grain ferments can effectively reduce cellular oxidative damage through the PI3K-AKT pathway at both the cellular and molecular levels. Some typical mRNAs (COL1A1, COL1A2, COL4A5, FN1, IGF2, NR4A1, and PIK3R1) were detected, and the results obtained were consistent with those of RNA-seq. These results may give us a common set of standards or criteria for the screen of anti-oxidative actives in the future.

Human skin responses to environmental pollutants: A review of current scientific models

Whatever the exposure route, chemical, physical and biological pollutants modify the whole organism response, leading to nerve, cardiac, respiratory, reproductive, and skin system pathologies. Skin acts as a barrier for preventing pollutant modifications. This review aims to present the available scientific models, which help investigate the impact of pollution on the skin. The research question was "Which experimental models illustrate the impact of pollution on the skin in humans?" The review covered a period of 10 years following a PECO statement on in vitro, ex vivo, in vivo and in silico models. Of 582 retrieved articles, 118 articles were eligible. In oral and inhalation routes, dermal exposure had an important impact at both local and systemic levels. Healthy skin models included primary cells, cell lines, co-cultures, reconstructed human epidermis, and skin explants. In silico models estimated skin exposure and permeability. All pollutants affected the skin by altering elasticity, thickness, the structure of epidermal barrier strength, and dermal extracellular integrity. Some specific models concerned wound healing or the skin aging process. Underlying mechanisms were an exacerbated inflammatory skin reaction with the modulation of several cytokines and oxidative stress responses, ending with apoptosis. Pathological skin models revealed the consequences of environmental pollutants on psoriasis, atopic dermatitis, and tumour development. Finally, scientific models were used for evaluating the safety and efficacy of potential skin formulations in preventing the skin aging process or skin irritation after repeated contact. The review gives an overview of scientific skin models used to assess the effects of pollutants. Chemical and physical pollutants were mainly represented while biological contaminants were little studied. In future developments, cell hypoxia and microbiota models may be considered as more representative of clinical situations. Models considering humidity and temperature variations may reflect the impact of these changes.

Role of miRNAs in melanin metabolism: Implications in melanin-related diseases

BACKGROUND

MicroRNAs (miRNAs) are short single-stranded non-coding RNAs that regulate degradation and expression of messenger RNA (mRNA) and play a wide range of key roles in different biological processes. They mediate different stages of melanocyte differentiation, growth, and apoptosis through a variety of pathways and can mediate melanin production by targeting key enzymes.

AIMS

This article was aimed to review the role of miRNAs in melanin metabolism and to introduce the role and significance of miRNAs in melanin-related diseases.

MATERIALS & METHODS

Systematic search and retrospective review were performed on the published data.

RESULTS

This paper reviews the process of melanin synthesis and the regulatory mechanism, explores the miRNA expression profiles in different model organisms, and introduces the mechanisms of several key miRNAs participating in melanin metabolism through target genes. We also explore the potential role of miRNA as a new target for the treatment of melanin metabolism disease, including vitiligo, melanoma, and chloasma.

CONCLUSION

miRNAs play a key role in melanin-related diseases, and the miRNAs involved may be potential therapeutic targets.

An ex vivo model of human skin photoaging induced by UVA radiation compatible with summer exposure in Brazil

Skin is the largest body organ and can be affected by several factors, such as ultraviolet (UV) radiation. UV radiation is subdivided in UVA, UVB and UVC according to the radiation wavelength. UVC radiation does not cross the ozone layer; UVB cause DNA damage and is closely related to carcinogenesis; UVA radiation penetrates deeply into the skin, reaching epidermis and dermis and is considered the main promoter of skin aging, known as photoaging. In order to understand photoaging mechanisms and propose efficient therapies, several photoaging study models have been developed, each with benefits and limitations, but most of them use very high doses of UVA radiation, which is not compatible with our daily sun exposure. The objective of this work was to develop a human ex vivo photoaging model induced by UVA exposure compatible to a summer in Brazil. For this, human skin fragments were obtained from healthy donors who underwent otoplasty surgery and skin explants were prepared and placed in plates, with the epidermis facing upwards. Skin explants were exposed to UVA at 16 J/cm² carried out by protocols of 2 or 4 exposures. Results showed an increase of oxidative damage, inflammatory cells, collagenolytic and elastolytic MMPs expression as well as a decrease of elastin expression, suggesting that the experimental model based on skin explants is able to evaluate UVA-induced aging in human skin.

Photobiomodulation induces microvesicle release in human keratinocytes: PI3 kinase-dependent pathway role

Microvesicles (MVs, 100-1000 nm diameter) are released into the extracellular environment by mammalian cells. MVs interact with near or remote cells through different mechanisms; in particular, MVs from human keratinocytes accelerate wound healing. Photobiomodulation by laser improves wound healing, but no information is available about its effects on MV release from human keratinocyte. Human-immortalized keratinocytes (human adult low-calcium high-temperature, HaCaT) were starved for 24 h and then irradiated using a 980-nm energy density of 0, 16.2, 32.5, and 48.7 J/cm². After 24 h, MVs released in the conditioned medium were isolated, stained, and quantified using flow cytometry. MVs were distinguished from exosomes on the basis of their volume (forward scatter signals). In some experiments, phosphatidylinositol 3-kinase (PI-3K) activity, involved in MV release and stimulated by laser light, was inhibited by pre-treating cells with Wortmannin (WRT, 10 μg/mL). MVs were observed in HaCaT-conditioned medium both in basal- and laser-stimulated conditions. Photobiomodulation therapy, also known as PBMT, was able to increase MV release from human keratinocytes reaching a maximum effect at 32.5 J/cm² with a stimulation of (148.6 ±15.1)% of basal (p<0.001). PI-3K activity inhibition strongly reduced both basal- and laser-induced MV release; but PBMT by laser still increased MV release, compared to basal values in the presence of WRT. In vitro near infrared photobiomodulation increased the releasing of MVs from human keratinocytes, while Wortmannin, a PI-3K inhibitor, negatively affects both basal- and laser-induced releasing. Laser-induced MV release could be a new effect of biostimulation on the wound healing process.

Synthesis of Kisspeptin-Mimicking Fragments and Investigation of their Skin Anti-Aging Effects

In recent years, a number of active materials have been developed to provide anti-aging benefits for skin and, among them, peptides have been considered the most promising candidate due to their remarkable and long-lasting anti-wrinkle activity. Recent studies have begun to elucidate the relationship between the secretion of emotion-related hormones and skin aging. Kisspeptin, a neuropeptide encoded by the KISS1 gene, has gained attention in reproductive endocrinology since it stimulates the reproductive axis in the hypothalamus; however, the effects of Kisspeptin on skin have not been studied yet. In this study, we synthesized Kisspeptin-10 and Kisspeptin-E, which are biologically active fragments, to mimic the action of Kisspeptin. Next, we demonstrated the anti-aging effects of the Kisspeptin-mimicking fragments using UV-induced skin aging models, such as UV-induced human dermal fibroblasts (Hs68) and human skin explants. Kisspeptin-E suppressed UV-induced 11 beta-hydroxysteroid dehydrogenase type 1 (11β-HSD1) stimulation leading to a regulation of skin aging related genes, including type I procollagen, matrix metalloproteinases-1 (MMP-1), interleukin-6 (IL-6), and IL-8, and rescued the skin integrity. Taken together, these results suggest that Kisspeptin-E could be useful to improve UV-induced skin aging by modulating expression of stress related genes, such as 11β-HSD1.

Protection against Ultraviolet A-Induced Skin Apoptosis and Carcinogenesis through the Oxidative Stress Reduction Effects of N-(4-bromophenethyl) Caffeamide, A Propolis Derivative

Ultraviolet A (UVA) is a major factor in skin aging and damage. Antioxidative materials may ameliorate this UV damage. This study investigated the protective properties of N-(4-bromophenethyl) caffeamide (K36H) against UVA-induced skin inflammation, apoptosis and genotoxicity in keratinocytes. The protein expression or biofactor concentration related to UVA-induced skin damage were identified using an enzyme-linked immunosorbent assay and western blotting. K36H reduced UVA-induced intracellular reactive oxygen species generation and increased nuclear factor erythroid 2–related factor 2 translocation into the nucleus to upregulate the expression of heme oxygenase-1, an intrinsic antioxidant enzyme. K36H inhibited UVA-induced activation of extracellular-signal-regulated kinases and c-Jun N-terminal kinases, reduced the overexpression of matrix metalloproteinase (MMP)-1 and MMP-2 and elevated the expression of the metalloproteinase-1 tissue inhibitor. Moreover, K36H inhibited the phosphorylation of c-Jun and downregulated c-Fos expression. K36H attenuated UVA-induced Bax and caspase-3 expression and upregulated antiapoptotic protein B-cell lymphoma 2 expression. K36H reduced UVA-induced DNA damage. K36H also downregulated inducible nitric oxide synthase, cyclooxygenase-2 and interleukin-6 expression as well as the subsequent generation of prostaglandin E₂ and nitric oxide. We observed that K36H ameliorated UVA-induced oxidative stress, inflammation, apoptosis and antiphotocarcinogenic activity. K36H can potentially be used for the development of antiphotodamage and antiphotocarcinogenic products.

Multifunctional fabric coatings with slow-releasing fragrance and UV resistant properties from ethyl cellulose/silica hybrid microcapsules

The synthesis of multifunctional microcapsules using natural polymers has contributed to a broad range of practical applications on fabric coatings. This paper presents a facile and environment-friendly approach for waterborne multifunctional fabric coatings by using cellulose/silica hybrid microcapsules. In this method, lavender fragrance oil-loaded cellulose/silica hybrid microcapsules were one-step synthesized via emulsion solvent diffusion. This microcapsule is core-shell structure with UV absorbers and methacrylic acid grafted silica in the shell and then added into the waterborne polysiloxane resins to form multifunctional fabric coatings. The as-obtained fabric coatings not only exhibited controlled lavender fragrance oil-releasing performance, and it can keep above 30 % fragrance after ninety days due to the slow releasing of lavender fragrance oil in the capsules, but also showed excellent UV resistant property with 159 UPF value.

Prevalent skin and dermatoses care in older adults treated at a private clinic and its relationship with comorbidities

Abstract Objectives : To identify and assess the prevalence of skin changes in the older adults surveyed, as well as to detect skin phototype according to the Fitzpatrick classification and to assess whether there was an association between the changes identified and predisposing factors (smoking, diabetes mellitus and hypertension). Additionally, evaluate the level of knowledge of the subjects regarding skin care. Method : A cross-sectional study was conducted in April to August 2018, based on a convenience sample of 80 older adults attending a private clinic. A questionnaire was applied among the subjects to identify their skin care and an answer sheet was completed by the researcher with information about the physical examination of the skin. Data were analyzed by the chi square or Fisher’s exact method. Poisson regression was used to determine the independent effect of the exploratory variables on the response variable. Results : The sampled population had a low level of education and was low-income and did not take proper care of their skin, while 70% were skin phototype 4. Most (73%) were aware of what skin cancer is and a significant portion 50% did not use sunscreen or moisturizer. There was no significant difference between the sexes (p>0.05). About half of the older adults reported having been instructed about skin care. Seventy two percent knew about the dangers of sun exposure. The most common skin alteration was melanosis and an association was found between diabetes and keratosis. Conclusions : The study population was low income, with a low level of education. They were exposed to the sun and did not make proper use of sunscreen or moisturizers, but sought health information from their doctor and knew what skin cancer was.