Ultraviolet Radiations: Skin Defense-Damage Mechanism

Ultraviolet Filters: Dissecting Current Facts and Myths

Skin cancer is a global and increasingly prevalent issue, causing significant individual and economic damage. UV filters in sunscreens play a major role in mitigating the risks that solar ultraviolet ra-diation poses to the human organism. While empirically effective, multiple adverse effects of these compounds are discussed in the media and in scientific research. UV filters are blamed for the dis-ruption of endocrine processes and vitamin D synthesis, damaging effects on the environment, induction of acne and neurotoxic and carcinogenic effects. Some of these allegations are based on scientific facts while others are simply arbitrary. This is especially dangerous considering the risks of exposing unprotected skin to the sun. In summary, UV filters approved by the respective governing bodies are safe for human use and their proven skin cancer-preventing properties make them in-dispensable for sensible sun protection habits. Nonetheless, compounds like octocrylene and ben-zophenone-3 that are linked to the harming of marine ecosystems could be omitted from skin care regimens in favor of the myriad of non-toxic UV filters.

Inhibition of UVB radiation-induced tissue swelling and immune suppression by nicotinamide riboside and pterostilbene

BACKGROUND

Environmental ultraviolet radiation has deleterious effects on humans, including sunburn and immune perturbations. These immune changes are involved in skin carcinogenesis.

OBJECTIVES

To determine whether nicotinamide riboside and/or pterostilbene administered systemically inhibits inflammatory and immune effects of exposure to mid-range ultraviolet radiation.

METHODS

To examine UVB radiation-induced inflammatory effects, mice were fed standard chow/water, 0.04% pterostilbene in chow and 0.2% nicotinamide riboside in drinking water, diet with nicotinamide riboside alone, or diet with pterostilbene alone. After 4 weeks, mice were exposed to UVB radiation (3500 J/m2), and 24-/48-h ear swelling was assessed. We also asked if each agent or the combination inhibits UVB radiation suppression of contact hypersensitivity in two models. Mice were fed standard diet/water or chow containing 0.08% pterostilbene, water with 0.4% nicotinamide riboside, or both for 4 weeks. Low-dose: Half the mice in each group were exposed on the depilated dorsum to UVB radiation (1700 J/m2) daily for 4 days, whereas half were mock-irradiated. Mice were immunized on the exposed dorsum to dinitrofluorobenzene 4 h after the last irradiation, challenged 7 days later on the ears with dinitrofluorobenzene, and 24-h ear swelling assessed. High dose: Mice were treated similarly except that a single dose of 10,000 J/m2 of radiation was administered and immunization was performed on the unirradiated shaved abdomen 3 days later.

RESULTS

Nicotinamide riboside and pterostilbene together inhibited UVB-induced skin swelling more than either alone. Pterostilbene alone and both given together could inhibit UVB-induced immune suppression in both the low-dose and high-dose models while nicotinamide riboside alone was more effective in the low-dose model than the high-dose model.

CONCLUSION

Nicotinamide riboside and pterostilbene have protective effects against UVB radiation-induced tissue swelling and immune suppression.

Ultra-Low-Dose UV-C Photo-stimulation Promotes Neural Stem Cells Differentiation via Presenilin 1 Mediated Notch and β-Catenin Activation

Light-based photo-stimulation has demonstrated promising effects on stem cell behavior, particularly in optimizing neurogenesis. However, the precise parameters for achieving optimal results, including the wavelengths, light intensity, radiating energy, and underlying mechanisms, remain incompletely understood. In this study, we focused on utilizing ultraviolet-C (UV-C) at a specific wavelength of 254 nm, with an ultra-low dose at intensity of 330 μW/cm2 and a total energy of 594 mJ/cm2 per day over a period of seven days, to stimulate the proliferation and differentiation of mouse neural stem cells (NSCs). The results revealed that the application of ultra-low-dose UV-C yielded the most significant effect in promoting differentiation when compared to mixed ultraviolet (UV) and ultraviolet-A (UV-A) radiation at equivalent exposure levels. The mechanism exploration elucidated the role of Presenilin 1 in mediating the activation of β-catenin and Notch 1 by the UV-C treatment, both of which are key factors facilitating NSCs proliferation and differentiation. These findings introduce a novel approach employing ultra-low-dose UV-C for specifically enhancing NSC differentiation, as well as the underlying mechanism. It would contribute valuable insights into brain stimulation and neurogenesis modulation for various diseases, offering potential therapeutic avenues for further exploration.

Use of Collagen in Cosmetic Products

Collagen (CLG) belongs to the family of fibrillar proteins and is composed of left-handed α polypeptide chains, which, twisting around themselves and their axis, form a right-handed superhelix. In the chemical structure, it contains mainly proline, hydroxyproline, glycine, and hydroxylysine. It occurs naturally in the dermis in the form of fibers that provide the skin with proper density and elasticity. The review aimed to present the types of collagen protein, factors affecting its structure and its unusual role in the functioning of the human body. Also, an overview of cosmetic products containing collagen or its derivatives, the characteristics of the formulas of these products, and the effects of their use were presented. Throughout the market, there are many cosmetic and cosmeceutical products containing CLG. They are in the form of fillers administered as injections, belonging to the group of the oldest tissue fillers; products administered orally and for topical use, such as creams, gels, serums, or cosmetic masks. Analyzed studies have shown that the use of products with collagen or its peptides improves the general condition of the skin and delays the aging process by reducing the depth of wrinkles, improving hydration (in the case of oral preparations), reducing transepithelial water loss (TEWL), as well as improving skin density and elasticity. In addition, oral application of bioactive CLG peptides has shown a positive effect on the nails, reducing the frequency of their breakage.

Knowledge, attitude, and practice toward photoaging in the Chinese population: a cross-sectional study

To investigate the knowledge, attitude, and practice (KAP) of photoaging in the Chinese population. This web-based cross-sectional study was conducted between January 2023 and March 2023 among the Chinese population aged 18-80 years old. Participants' knowledge, attitude, and practice toward photoaging were collected through a self-administered questionnaire. A total of 830 questionnaires were collected, with 826 valid questionnaires and an efficiency rate of 99.52%. There were 274 (33.17%) males and 532 (64.41%) aged 31-51 years old. The average knowledge, attitude, and practice scores were 7 (4, 9) (possible range 0-12), 31.5 (28, 34) (possible range 8-40), and 33 (24, 42) (possible range 11-55), respectively, indicating poor knowledge, good attitude, and moderate practice. Spearman correlation analysis showed that knowledge was negatively correlated with attitude (r = - 0.111, P < 0.05) and practice (r = - 0.113, P < 0.05), and attitude was positively correlated with practice (r = 0.992, P < 0.05). The multivariable linear regression model showed that for each point increase in attitude score, the practice score increased by 2.96 points (β = 2.96, 95% CI 2.91-3.01, P < 0.001). The Chinese population has poor knowledge, good attitude, and moderate practice toward photoaging. A good attitude toward photoaging would lead to good practice, and more outreach and education for the Chinese population might be needed.

Current insights and future perspectives of ultraviolet radiation (UV) exposure: Friends and foes to the skin and beyond the skin

Ultraviolet (UV) radiation is ubiquitous in the environment, which has been classified as an established human carcinogen. As the largest and outermost organ of the body, direct exposure of skin to sunlight or UV radiation can result in sunburn, inflammation, photo-immunosuppression, photoaging and even skin cancers. To date, there are tactics to protect the skin by preventing UV radiation and reducing the amount of UV radiation to the skin. Nevertheless, deciphering the essential regulatory mechanisms may pave the way for therapeutic interventions against UV-induced skin disorders. Additionally, UV light is considered beneficial for specific skin-related conditions in medical UV therapy. Recent evidence indicates that the biological effects of UV exposure extend beyond the skin and include the treatment of inflammatory diseases, solid tumors and certain abnormal behaviors. This review mainly focuses on the effects of UV on the skin. Moreover, novel findings of the biological effects of UV in other organs and systems are also summarized. Nevertheless, the mechanisms through which UV affects the human organism remain to be fully elucidated to achieve a more comprehensive understanding of its biological effects.

PTCH1 gene variants rs357564, rs2236405, rs2297086 and rs41313327, mRNA and tissue expression in basal cell carcinoma patients from Western Mexico

BACKGROUND

Basal cell carcinoma (BCC) represents about 80% of all cases of skin cancer. The PTCH1 is a transmembrane protein of the Sonic Hedgehog signaling pathway that regulates cell proliferation. Genetic variants in PTCH1 gene have been previously described in association with BCC development. In addition, PTCH1 mRNA and protein expression analysis are also significant to understand its role in skin cancer physiopathology.

METHODS

An analytical cross-sectional study was performed, and a total of 250 BCC patients and 290 subjects from the control group (CG) were included, all born in western Mexico. The genotypes and relative expression of the mRNA were determined by TaqMan® assay. The protein expression was investigated in 70 BCC paraffin-embedded samples with PTCH1 antibodies. Semi-quantitative analysis was performed to determine the expression level in the immunostained cells.

RESULTS

We did not find evidence of an association between PTCH1 rs357564, rs2297086, rs2236405, and rs41313327 genetic variants and susceptibility to BCC. Likewise, no statistically significant differences were found in the comparison of the mRNA level expression between BCC and CG (p > 0.05). The PTCH1 protein showed a low expression in 6 of the analyzed samples and moderate expression in 1 sample. No association was found between genetic variants, protein expression, and demographic-clinical characteristics (p > 0.05).

CONCLUSION

The studied PTCH1 variants may not be associated with BCC development in the Western Mexico population. The PTCH1 mRNA levels were lower in patients with BCC compared to the control group, but its protein was underexpressed in the tissue samples.

A review of factors influencing sensitive skin: an emphasis on built environment characteristics

Background

Sensitive skin (SS) is a condition characterized by hyperreactivity. Impacting around 37 percent of the worldwide population and exerting an influence on the quality of life for affected individuals. Its prevalence rate has increased due to factors such as elevating stress levels and deteriorating environmental conditions. The exposome factors influencing SS have extended from demographic, biological attributes, and lifestyle to external environments. Built environments (BEs) have demonstrated as root drivers for changes in behaviors and environmental exposure which have the potential to trigger SS, but the review of the associations between BEs and SS is currently lacking.

Objective

This review aims to achieve two primary objectives: (1) Examine exposome factors that exert influence on SS at the individual and environmental levels. (2) Develop a theoretical framework that establishes a connection between BEs and SS, thereby offering valuable insights into the impact of the built environment on this condition.

Methods

An extensive literature search was carried out across multiple fields, including sociology, epidemiology, basic medicine, clinical medicine, and environmental research, with a focus on SS. To identify pertinent references, renowned databases such as PubMed, Web of Science, and CNKI were utilized.

Results

SS is the outcome of interactions between individual attributes and environmental factors. These influencing factors can be categorized into five distinct classes: (1) demographic and socioeconomic characteristics including age, gender, and race; (2) physiological and biological attributes such as emotional changes, skin types, sleep disorders, and menstrual cycles in women; (3) behavioral factors, such as spicy diet, cosmetic use, alcohol consumption, and physical exercise; (4) natural environmental features, including climate conditions and air pollution; (5) built environmental features such as population density, green space availability, road network density, and access to public transportation, also have the potential to affect the condition.

Conclusion

The importance of interdisciplinary integration lies in its ability to ascertain whether and how BEs are impacting SS. By elucidating the role of BEs in conjunction with other factors in the onset of SS, we can provide guidance for future research endeavors and the formulation of interventions aimed at mitigating the prevalence of SS.

Ultraviolet-C light at 222 nm has a high disinfecting spectrum in environments contaminated by infectious pathogens, including SARS-CoV-2

Ultraviolet light (UV) acts as a powerful disinfectant and can prevent contamination of personal hygiene from various contaminated environments. The 222-nm wavelength of UV-C has a highly effective sterilization activity and is safer than 275-nm UV-C. We investigated the irradiation efficacy of 222-nm UV-C against contaminating bacteria and viruses in liquid and fabric environments. We conducted colony-forming unit assays to determine the number of viable cells and a 50% tissue culture infectious dose assay to evaluate the virus titration. A minimum dose of 27 mJ/cm2 of 222-nm UV-C was required for >95% germicidal activity for gram-negative and -positive bacteria. A 25.1 mJ/cm2 dose could ensure >95% virucidal activity against low-pathogenic avian influenza virus and severe acute respiratory syndrome coronavirus (SARS-CoV-2). In addition, this energy dose of 222-nm UV-C effectively inactivated SARS-CoV-2 variants, Delta and Omicron. These results provide valuable information on the disinfection efficiency of 222-nm UV-C in bacterial and virus-contaminated environments and can also develop into a powerful tool for individual hygiene.

A novel UVA-associated circUBE2I mediates ferroptosis in HaCaT cells

Alternative splicing of precursor messenger RNA (pre-mRNA), including linear splicing and back splicing, produces multiple isoforms that lead to diverse cell fates in response to stimuli including ultraviolet radiation (UVR). Although UVR-induced linear gene splicing has been extensively studied in skin cells, the UVR-induced gene back-splicing events that lead to the production of circular RNAs (circRNAs) have not been thoroughly investigated. The present study used circRNA transcriptome sequencing to screen the differentially expressed circRNAs in human keratinocytes (HaCaT) after UVA irradiation. A total of 312 differentially expressed circRNAs were found in HaCaT cells post-UVR. Among the UVA-induced differentially expressed circRNAs, circUBE2I-a novel circRNA formed by exons 2-6 of the UBE2I gene-was the most significantly upregulated circRNA. RT-qPCR assay further confirmed the increase of circUBE2I level in HaCaT cells after UVA irradiation or H2 O2 treatment. RNase R digestion experiment revealed the stability of circUBE2I. Overexpression of circUBE2I in keratinocytes induced ferroptosis after UVA or H2 O2 , preventable by the ferroptosis inhibitor ferrostatin-1. Our study provides new insights into the role of circular RNAs in UVA-induced skin cell damage and suggests that circUBE2I could be a therapeutic target in UVR-aroused ferroptosis in skin cells.

Preclinical safety evaluation of continuous UV-A lighting in an operative setting

BACKGROUND

Germicidal ultraviolet (UV-C) light has been shown as an effective modality for disinfection in laboratory settings and in the operative room. Traditionally, short-wavelength UV-C devices, which have previously been shown to cause DNA damage, are utilized only for disinfection in pre- and post-operative settings and are not continuously active during operations. Continuous use of intraoperative UV light has potential to decrease pathogens and subsequent surgical site infections (SSIs), which arise in approximately 5-15% of operative cases. SSIs are a significant determinant of patient morbidity, readmission rates, and overall cost. Therefore, a method of UV light disinfection with a low risk of DNA damage is needed so that greater antimicrobial protection can be afforded to patients during the entirety of their surgical procedures. A new disinfection device that harnesses longer-wavelength UV-A light to disinfect the surgical field throughout the entirety of the procedure, including pre- and post-operation has been developed.

METHODS

This study aimed to determine if UV-A light administered intraoperatively was safe, as defined by the minimal presence of DNA damage and safe amounts of reflection upon medical personnel. Using in vitro models, we examined the differential impacts of UV-C and UV-A light on DNA damage and repair pathways. In a murine model, we looked at the production of DNA damage photoproduction in relation to UV-A versus UV-C exposure.

RESULTS

Our results show UV-A light does not induce a significant amount of DNA damage at the cellular or tissue level. Furthermore, a preclinical porcine study showed that surgical personnel were exposed to safe levels of UV-A irradiance from an overhead UV-A light used during an operation. The amount of UV-A transmitted through surgical personal protective equipment (PPE) also remained within safe levels.

CONCLUSIONS

In conclusion, we found that UV-A may be safe for intraoperative use.

Guarding skin under PPE: Mechanistic insights and technological innovations

In the presence of diseases transmitted through respiratory droplets and direct contact, healthcare workers (HCWs) necessitate the use of personal protective equipment (PPE). For optimal safety, PPE should securely conform to the skin during extended wear. However, conventional PPE often lacks adequate air permeability and hygroscopicity, trapping heat and moisture emitted by the body within the enclosure. Such a hot and humid internal environment can induce skin damage, such as erythema, rash, pruritus, and itching among others, leading to microbial growth on the skin surface, the production of inflammatory mediators at the wound site and an increased risk of infection. This review strives to comprehensively elucidate the fundamental mechanisms triggering adverse skin reactions and their resultant manifestations. Furthermore, we explore recent advancements aimed at inhibiting these mechanisms to effectively mitigate the occurrence of skin lesions.

Proteomics analysis to investigate the potential mechanism of theacrine against UV-induced skin photodamage

AIM

This study aimed to explore the underlying mechanism of theacrine treatment of UV-induced skin photodamage.

MATERIALS AND METHODS

Tandem Mass Tag (TMT) relative quantitative proteomics analysis was used to characterize the proteins and pathways associated with the ability of theacrine to combat photodamage in mouse skin by modeling UV irradiation of the backs of ICR mice.

RESULTS

Apoptosis-related proteins and signaling pathways play a key role in the ability of theacrine to protect against skin photodamage, according to proteomic and bioinformatics analysis; molecular docking and Western blotting further revealed that theacrine was associated with apoptosis-related proteins (p53, Bcl-2, Bax, caspase-3, and cleaved-caspase-3) with strong binding affinity, which can significantly reduce skin cell apoptosis induced by UV exposure.

CONCLUSION

The findings revealed that theacrine can reduce UVB-induced epidermal damage by controlling the apoptosis signaling pathway, implying that theacrine could be a useful anti-UVB damage agent.

Study on the Antioxidant Effect of Shikonin-Loaded β-Cyclodextrin Forming Host-Guest Complexes That Prevent Skin from Photoaging

When the skin is overexposed to ultraviolet rays, free radicals will accumulate in the skin, causing lipid damage and even inducing photoaging of the skin. Combination therapy with antioxidant drugs is a good choice for topical treatment of skin photoaging due to its special physiological structure. In this paper, shikonin was encapsulated in β-cyclodextrin (SH-β-CD) by the precipitation crystallization method, which delayed the release of the drug and increased drug solubility. The average diameter of SH-β-CD was 203.0 ± 21.27 nm with a zeta potential of -14.4 ± 0.5 mV. The encapsulation efficiency (EE%) was 65.9 ± 7.13%. The results of the in vitro permeation across the dialysis membrane and ex vivo transdermal release rates were 52.98 ± 1.21% and 88.25 ± 3.26%, respectively. In vitro antioxidant and antilipid peroxidation model assay revealed the antioxidant potential of SH and SH-β-CD. In the mice model of skin photoaging, SH and SH-β-CD had a recovery effect on the skin damage of mice, which could significantly increase the superoxide dismutase (SOD) activity in the skin. Briefly, SH-β-CD had an obvious therapeutic effect on the skin photoaging of mice caused by UV, and it is promising in skin disease treatment and skin care.

Nutrition and melanoma: the contribution of trace elements in onset, progression, and treatment of melanoma

Melanoma is a highly malignant and drug-resistant disease that imposes a substantial economic burden on the world. There are many studies linking trace elements to diverse types of cancers, including melanoma. This review elucidates the relationship between trace elements exposure and melanoma. It was identified that copper, manganese, selenium, zinc, iron, and many other trace elements were associated with melanoma in humans. In terms of epidemiology, different elements have different correlations with melanoma. These trace elements affect the occurrence and development of melanoma through various mechanisms, such as oxidative stress and the MAPK pathway. The literature on the role of trace elements in the pathogenesis and treatment of melanoma depicts promising prospects for this field.

MiRNA-related metastasis in oral cancer: moving and shaking

Across the world, oral cancer is a prevalent tumor. Over the years, both its mortality and incidence have grown. Oral cancer metastasis is a complex process involving cell invasion, migration, proliferation, and egress from cancer tissue either by lymphatic vessels or blood vessels. MicroRNAs (miRNAs) are essential short non-coding RNAs, which can act either as tumor suppressors or as oncogenes to control cancer development. Cancer metastasis is a multi-step process, in which miRNAs can inhibit or stimulate metastasis at all stages, including epithelial-mesenchymal transition, migration, invasion, and colonization, by targeting critical genes in these pathways. On the other hand, long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), two different types of non-coding RNAs, can regulate cancer metastasis by affecting gene expression through cross-talk with miRNAs. We reviewed the scientific literature (Google Scholar, Scopus, and PubMed) for the period 2000-2023 to find reports concerning miRNAs and lncRNA/circRNA-miRNA-mRNA networks, which control the spread of oral cancer cells by affecting invasion, migration, and metastasis. According to these reports, miRNAs are involved in the regulation of metastasis pathways either by directly or indirectly targeting genes associated with metastasis. Moreover, circRNAs and lncRNAs can induce or suppress oral cancer metastasis by acting as competing endogenous RNAs to inhibit the effect of miRNA suppression on specific mRNAs. Overall, non-coding RNAs (especially miRNAs) could help to create innovative therapeutic methods for the control of oral cancer metastases.

Cycloastragenol exerts protective effects against UVB irradiation in human dermal fibroblasts and HaCaT keratinocytes

BACKGROUND

Cycloastragenol (CAG) is a triterpene aglycone of astragaloside IV that possesses various pharmacological actions including improving telomerase activity, inhibiting inflammation and cell proliferation, inducing apoptosis.

OBJECTIVE

CAG has also shown effect to significantly improve the appearance of aging skin but, its molecular mechanism of protective effect against UVB induced-damage have not been elucidated. We investigated the potential effect of CAG on UVB wrinkle promoting activities and skin-moisturizing effects in human dermal fibroblasts (HDF) and HaCaT keratinocytes.

METHODS

After UVB irradiation or H2O2 treatment, the levels of matrix metalloproteinases (MMPs) and ROS generation were measured in CAG-treated HDF cells. In addition, after UVB irradiation, hyaluronic acid and skin hydration factors (filaggrin and SPT) were also analyzed in CAG (0-0.5-1-2 µM)-treated HDF and HaCaT cells.

RESULTS

We found that CAG caused a significant decrease in the levels of UVB-induced MMP-1, MMP-9, MMP-13 and ROS generation, also increased UVB-damaged Collagen Ⅰ. We also noted that CAG increased cell viability and can regulate MMP-1, MMP-9, MMP-13and Collagen Ⅰ in H2O2-damaged HDF cells. Moreover, we noticed that CAG effectively enhanced levels of hyaluronic acid and expression of skin hydration factors (filaggrin and serine palmitoyltransferase (SPT)) in UVB-damaged HDF and HaCaT cells.

CONCLUSION

This is first report indicating that CAG can exhibit protective effect against UVB and H2O2-induced damages and can contribute in maintenance of healthy skin.

The meaning of adaptation in aging: insights from cellular senescence, epigenetic clocks and stem cell alterations

With recent rapid progress in research on aging, there is increasing evidence that many features commonly considered to be mechanisms or drivers of aging in fact represent adaptations. Here, we examine several such features, including cellular senescence, epigenetic aging and stem cell alterations. We draw a distinction between the causes and consequences of aging and define short-term consequences as 'responses' and long-term ones as 'adaptations'. We also discuss 'damaging adaptations', which despite having beneficial effects in the short term, lead to exacerbation of the initial insult and acceleration of aging. Features commonly recognized as 'basic mechanisms of the aging process' are critically examined for the possibility of their adaptation-driven emergence from processes such as cell competition and the wound-like features of the aging body. Finally, we speculate on the meaning of these interactions for the aging process and their relevance for the development of antiaging interventions.

Beneficial Effects of Plant-Based Diets on Skin Health and Inflammatory Skin Diseases

The human skin is a crucial organ that protects the organism from the outer environment. Skin integrity and health depend on both extrinsic and intrinsic factors. Intrinsic factors such as aging and genetic background contribute to weakened skin and disease susceptibility. Meanwhile, extrinsic factors including UV radiation, pollution, smoking, humidity, and poor diet also affect skin health and disease. On the other hand, healthy dietary patterns such as plant-based diets have gained popularity as a complementary therapy for skin health. A plant-based diet is defined as all diets based on plant foods, including an abundance of vegetables, fruits, beans, lentils, legumes, nuts, seeds, fungi, and whole grains, with limited or no animal products or processed foods. However, some authors also exclude or limit processed foods in the definition. Recent research has shown that these diets have beneficial effects on inflammatory skin diseases. This review explored the beneficial effects of plant-based diets on inflammatory skin diseases and plant-based functional foods on healthy skin. In conclusion, plant-based diets and plant-based functional foods may have beneficial effects on skin health through the gut microbiome.

UVA/UVB Irradiation Exerts a Distinct Phototoxic Effect on Human Keratinocytes Compared to Human Malignant Melanoma Cells

Solar ultraviolet radiation (UVR) is responsible for the development of many skin diseases, including malignant melanoma (MM). This study assessed the phototoxic effects of UVA, and UVB radiations on healthy and pathologic skin cells by evaluating the behavior of human keratinocytes (HaCaT) and MM cells (A375) at 24 h post-irradiation. The main results showed that UVA 10 J/cm² exerted no cytotoxicity on HaCaT and A375 cells, while UVB 0.5 J/cm² significantly reduced cell viability and confluence, induced cell shrinkage and rounding, generated nuclear and F-actin condensation, and induced apoptosis by modulating the expressions of Bax and Bcl-2. The association of UVA 10 J/cm² with UVB 0.5 J/cm² (UVA/UVB) induced the highest cytotoxicity in both cell lines (viability < 40%). However, the morphological changes were different-HaCaT cells showed signs of necrosis, while in A375 nuclear polarization and expulsion from the cells were observed, features that indicate enucleation. By unraveling the impact of different UVR treatments on the behavior of normal and cancer skin cells and describing enucleation as a novel process involved in the cytotoxicity of UVA/UVB irradiation, these findings bridge the gap between the current and the future status of research in the field.

Protective Effects of a Jellyfish-Derived Thioredoxin Fused with Cell-Penetrating Peptide TAT-PTD on H2O2-Induced Oxidative Damage

Thioredoxin (Trx) plays a critical role in maintaining redox balance in various cells and exhibits anti-oxidative, anti-apoptotic, and anti-inflammatory effects. However, whether exogenous Trx can inhibit intracellular oxidative damage has not been investigated. In previous study, we have identified a novel Trx from the jellyfish Cyanea capillata, named CcTrx1, and confirmed its antioxidant activities in vitro. Here, we obtained a recombinant protein, PTD-CcTrx1, which is a fusion of CcTrx1 and protein transduction domain (PTD) of HIV TAT protein. The transmembrane ability and antioxidant activities of PTD-CcTrx1, and its protective effects against H₂O₂-induced oxidative damage in HaCaT cells were also detected. Our results revealed that PTD-CcTrx1 exhibited specific transmembrane ability and antioxidant activities, and it could significantly attenuate the intracellular oxidative stress, inhibit H₂O₂-induced apoptosis, and protect HaCaT cells from oxidative damage. The present study provides critical evidence for application of PTD-CcTrx1 as a novel antioxidant to treat skin oxidative damage in the future.

Melatonin inhibits senescence-associated melanin pigmentation through the p53-TYR pathway in human primary melanocytes and the skin of C57BL/6 J mice after UVB irradiation

UVB exposure accelerates skin aging and pigmentation. Melatonin effectively regulates tyrosinase (TYR) activity and aging. The purpose of this study was to determine the association between premature senescence and pigmentation, and the mechanism of melanin synthesis effected by melatonin. Primary melanocytes were extracted and identified from the male foreskin. To inhibit TYR expression, primary melanocytes were transduced with the lentivirus pLKD-CMV-EGFP-2A-Puro-U6-TYR. The wild-type TYR^(+/+) and TYR^(-/-) or TYR^(+/-) knockout C57BL/6 J mice were used to determine the role of TYR on melanin synthesis in vivo. Results showed that UVB-induced melanin synthesis is dependent on TYR in primary melanocytes and mice. Furthermore, in primary melanocytes pretreated with Nutlin-3 or PFT-α to up or downregulate p53, results showed that premature senescence and melanin synthesis increased in primary melanocytes after UVB irradiation at 80 mJ/cm², and further increased after being treated with Nutlin-3, while significantly decreased with PFT-α. In addition, melatonin inhibited UVB-induced premature senescence associated with inactivation of p53 and phosphorylation of p53 on Ser15 (ser-15), a decrease of melanin synthesis accompanied by reduced TYR expression. Moreover, skin erythema and pigmentation induced by UVB were reduced in the dorsal and ear skin of mice topically pretreated with 2.5% melatonin. These indicate that melatonin inhibits UVB-induced senescence-associated pigmentation via the p53-TYR pathway in primary melanocytes and prevents pigmentation obviously in the dorsal and ear skin of C57BL/6 J mice after UVB irradiation. KEY MESSAGES: P53 links UVB irradiation-induced senescence and senescence-associated pigmentation and regulates TYR in primary melanocytes after UVB irradiation. Melatonin inhibits senescence-associated pigmentation through the p53-TYR pathway in primary melanocytes. Melatonin prevents skin erythema and melanin pigmentation induced by UVB irradiation in the dorsal and ear skin of C57BL/6J mice.

Regulation of XPC Binding Dynamics and Global Nucleotide Excision Repair by p63 and Vitamin D Receptor

p63 and the vitamin D receptor (VDR) play important roles in epidermal development and differentiation, but their roles and relationship in the response to ultraviolet (UV) radiation are less clear. Using TERT-immortalized human keratinocytes expressing shRNA targeting p63 in concert with exogenously applied siRNA targeting VDR, we assessed p63 and VDR's separate and combined effect on nucleotide excision repair (NER) of UV-induced 6-4 photoproducts (6-4PP). Knockdown of p63 reduced VDR and XPC expression relative to nontargeting controls, while knockdown of VDR had no effect on p63 and XPC protein expression, though alone it modestly reduced XPC mRNA. Upon UV irradiation through filters with 3 μm pores to create spatially discrete spots of DNA damage, keratinocytes depleted of p63 or VDR exhibited slower removal of 6-4PP than control cells over the first 30 min. Costaining of control cells with antibodies to XPC revealed that XPC accumulated at DNA damage foci, peaking within 15 min and gradually fading over 90 min as NER proceeded. In either p63- or VDR-depleted keratinocytes, XPC overaccumulated at spots of DNA damage so that 50% more XPC was retained at 15 min and 100% more XPC was retained at 30 min than in control cells, suggesting dissociation of XPC after binding was also delayed. Concurrent knockdown of VDR and p63 resulted in similar impairment of 6-4PP repair and XPC overaccumulation but even slower release of XPC from DNA damage sites such that 200% more XPC was retained relative to controls at 30 min post-UV. These results suggest that VDR accounts for some of p63's effects in delaying 6-4PP repair associated with overaccumulation and slower dissociation of XPC, though p63's regulation of basal XPC expression appears to be VDR-independent. The results are consistent with a model where XPC dissociation is an important step during NER and that failure to do so may inhibit subsequent repair steps. This work further links two important regulators of epidermal growth and differentiation to the DNA repair response to UV.

Antiphotoaging and Skin-Protective Activities of Ardisia silvestris Ethanol Extract in Human Keratinocytes

Ardisia silvestris is a traditional medicinal herb used in Vietnam and several other countries. However, the skin-protective properties of A. silvestris ethanol extract (As-EE) have not been evaluated. Human keratinocytes form the outermost barrier of the skin and are the main target of ultraviolet (UV) radiation. UV exposure causes skin photoaging via the production of reactive oxygen species. Protection from photoaging is thus a key component of dermatological and cosmetic products. In this research, we found that As-EE can prevent UV-induced skin aging and cell death as well as enhance the barrier effect of the skin. First, the radical-scavenging ability of As-EE was checked using DPPH, ABTS, TPC, CUPRAC, and FRAP assays, and a 3-(4-5-dimethylthiazol-2-yl)-2-5-diphenyltetrazolium bromide assay was used to examine cytotoxicity. Reporter gene assays were used to determine the doses that affect skin-barrier-related genes. A luciferase assay was used to identify possible transcription factors. The anti-photoaging mechanism of As-EE was investigated by determining correlated signaling pathways using immunoblotting analyses. As-EE had no harmful effects on HaCaT cells, according to our findings, and As-EE revealed moderate radical-scavenging ability. With high-performance liquid chromatography (HPLC) analysis, rutin was found to be one of the major components. In addition, As-EE enhanced the expression levels of hyaluronic acid synthase-1 and occludin in HaCaT cells. Moreover, As-EE dose-dependently up-regulated the production of occludin and transglutaminase-1 after suppression caused by UVB blocking the activator protein-1 signaling pathway, in particular, the extracellular response kinase and c-Jun N-terminal kinase. Our findings suggest that As-EE may have anti-photoaging effects by regulating mitogen-activated protein kinase, which is good news for the cosmetics and dermatology sectors.

Melanopsin (OPN4) is a novel player in skin homeostasis and attenuates UVA-induced effects

The presence of melanopsin (OPN4) has been shown in cultured murine melanocytes and was associated with ultraviolet A radiation (UVA) reception. Here we demonstrated the protective role of OPN4 in skin physiology and the increased UVA-induced damage in its absence. Histological analysis showed a thicker dermis and thinner hypodermal white adipose tissue layer in Opn4^-/- (KO) mice than in wild-type (WT) animals. Proteomics analyses revealed molecular signatures associated with proteolysis, remodeling chromatin, DNA damage response (DDR), immune response, and oxidative stress coupled with antioxidant responses in the skin of Opn4 KO mice compared to WT. Skin protein variants were found in Opn4 KO mice and Opn2, Opn3, and Opn5 gene expressions were increased in the genotype. We investigated each genotype response to UVA stimulus (100 kJ/m²). We found an increase of Opn4 gene expression following stimulus on the skin of WT mice suggesting melanopsin as a UVA sensor. Proteomics findings suggest that UVA decreases DDR pathways associated with ROS accumulation and lipid peroxidation in the skin of Opn4 KO mice. Relative changes in methylation (H3-K79) and acetylation sites of histone between genotypes and differentially modulated by UVA stimulus were also observed. We also identified alterations of molecular traits of the central hypothalamus-pituitary- adrenal (HPA) and the skin HPA-like axes in the absence of OPN4. Higher skin corticosterone levels were detected in UVA-stimulated Opn4 KO compared to irradiated WT mice. Taken altogether, functional proteomics associated with gene expression experiments allowed a high-throughput evaluation that suggests an important protective role of OPN4 in regulating skin physiology in the presence and absence of UVA radiation.

The genetic basis and potential molecular mechanism of yellow-albino northern snakehead (Channa argus)

Body colour is an important economic trait for commercial fishes. Recently, a new colour morph displaying market-favoured yellow skin (termed as yellow-mutant, YM) of northern snakehead (Channa argus) was discovered in China. We confirmed that YM snakehead is an albino with complete loss of melanin in the skin and eyes by histological and ultrastructural observations, and inherited as a recessive Mendelian trait. By applying genomic analysis approaches, in combination with gene knockdown and rescue experiments, we suggested a non-sense mutation in slc45a2 (c.383G > A) is the causation for the YM snakehead. Notably, significantly higher levels of key melanogenesis genes (tyr, tyrp1, dct and pmel) and phospho-MITF protein were detected in YM snakehead than those in wild-type individuals, and the underlying mechanism was further investigated by comparative transcriptomic analysis. Results revealed that differential expressed genes involved in pathways like MAPK, WNT and calcium signalling were significantly induced in YM snakehead, which might account for the increased amount of melanogenesis elements, and presumably be stimulated by fibroblast-derived melanogenic factors in a paracrine manner. Our study clarified the genetic basis of colour variation in C. argus and provided the preliminary clue indicating the potential involvement of fibroblasts in pigmentation in fish.

Inflammatory stimulus worsens the effects of UV-A exposure on J774 cells

UV-A radiation affects skin homeostasis by promoting oxidative distress. Endogenous photosensitizers in the dermis and epidermis of human skin absorb UV-A radiation forming excited states (singlet and triplet) and reactive oxygen species (ROS) producing oxidized compounds that trigger biological responses. The activation of NF-kB induces the expression of pro-inflammatory cytokines and can intensify the generation of ROS. However, there is no studies evaluating the cross talks between inflammatory stimulus and UV-A exposure on the levels of redox misbalance and inflammation. In here, we evaluated the effects of UV-A exposure on J774 macrophage cells previously challenged with LPS in terms of oxidative distress, release of pro-inflammatory cytokines, and activation of regulated cell death pathways. Our results showed that LPS potentiates the dose-dependent UV-A-induced oxidative distress and cytokine release, in addition to amplifying the regulated (autophagy and apoptosis) and non-regulated (necrosis) mechanisms of cell death, indicating that a previous inflammatory stimulus potentiates UV-A-induced cell damage. We discuss these results in terms of the current-available skin care strategies.

UV-induced skin's green autofluorescence is a biomarker for both non-invasive evaluations of the dosages of UV exposures of the skin and non-invasive prediction of UV-induced skin damage

It is crucial to discover biomarkers for non-invasive evaluations of the dosages of UV exposures to a person during post-UV exposure period, and for non-invasive prediction of UV-induced skin damage. Our current study has obtained findings: UVB exposures produced dose-dependent increases in skin's green autofluorescence (AF) intensity of mice, which were significantly associated with the UVB dosages. The UVC-induced green AF increases were dose dependent, which were highly associated with the UVC dosages. Moreover, both previous reports and our current study have collectively shown significant association between UVB/UVC dosages and UVB/UVC-induced skin damage. Collectively, our study has indicated that the UVB/UVC-induced skin's AF are first biomarkers for both non-invasive evaluations of the dosages of UV exposures to a person during post-UV exposure period and non-invasive and label-free prediction of UVB/UVC-induced skin damage.

UV C Light from a Light-Emitting Diode at 275 Nanometers Shortens Wound Healing Time in Bacterium- and Fungus-Infected Skin in Mice

Due to the changes in pathogenic species and the absence of research on topical skin antibiotics, the therapy of skin and soft tissue infections (SSTIs) is facing more and more severe challenges. It is particularly urgent to look for alternative therapies without induction of drug resistance. UV C (UVC) light within the range of 200 to 280 nm is one of the most common techniques used to kill and/or inactivate pathogenic microorganisms. However, the traditional most commonly used wavelength of 254 nm irradiated from a low-pressure mercury lamp is hazardous to human health, being both carcinogenic and damaging to eye tissues, which limits its applications in vivo. This research aimed to investigate the antimicrobial properties and influence of 275-nm UVC light from a light-emitting diode (UVC-LED light) on wound healing time. Five bacteria, three fungi, and scalded-mouse models combined with SSTIs were used to evaluate the antimicrobial effect in vitro and in vivo. 275-nm UVC-LED light inactivated both bacteria and fungi with a very short irradiation time in vitro and induced neither DNA damage nor epidermal lesions in the mice's skin. Furthermore, in mouse models of SSTIs induced by either methicillin-resistant Staphylococcus aureus (MRSA) or Candida albicans, the 275-nm UVC-LED light showed significant antimicrobial effects and shortened the wound healing time compared with that in the no-irradiation group. UVC-LED light at 275 nm has the potential to be a new form of physical therapy for SSTIs. IMPORTANCE As a common clinical problem, the therapy of SSTIs is facing growing challenges due to an increase in the number of drug-resistant bacteria and fungi. UV C (UVC) light sterilization has been widely used in all aspects of daily life, but there are very few reports about in vivo therapy using UVC light. It is well known that prolonged exposure to UVC light increases the possibility of skin cancer. In addition, it is also very harmful for eyes. UV irradiation with 254-nm UVC light can cause corneal damage, like thinning of the corneal epithelial layer, superficial punctate keratitis, corneal erosion, etc. In this study, we focused on looking for a more accessible light source and safer UVC wavelength, and 275-nm UVC LED light was chosen. We investigated its applicability for SSTIs therapy with relative skin safety and expected that it could be used as a new physical therapy method for SSTIs.

Delivery of superoxide dismutase by TAT and abalone peptides for the protection of skin cells against oxidative stress

Trichoderma reesei superoxide dismutase (TrSOD) is a well-characterized enzyme being stable between 30 and 90°C for 1 h with activity at pH between 2.6 and 9.0. This work aimed to clone, express, purify, and evaluate the protective effect antioxidant of this enzyme on skin cells when fused to transactivator of transcription (TAT) protein transduction domain of HIV-1 and abalone (Ab) peptides to allow cell penetration. TrSOD, TAT-TrSOD-Yfp (fused to yellow fluorescent protein), and Ab-TrSOD were expressed in E. coli and purified as soluble proteins. The cytotoxicity of the enzymes, at the concentrations of 1, 3, and 6 μmol/L, was evaluated for a period of 24 and 48 h of incubation, with no cytotoxic effect on 3T3 fibroblasts. The 3T3 cells were exposed to the oxidant agent tert-butyl hydroperoxide and evaluated for reactive oxygen species (ROS) generation, in the presence or not of the recombinant enzymes. TAT-TrSOD-Yfp was able to decrease the generation of ROS by 15% when used in the concentrations of 3 and 6 μmol/L in comparison to the control, but there was no difference in relation to the effect of TrSOD. Ab-TrSOD, when compared to TrSOD, promoted a decrease in the formation of ROS of 19% and 14% at the concentrations of 1 and 6 μmol/L, respectively, indicating that this recombinant form was more effective in reducing oxidative stress compared to SOD without the cell-penetrating peptide (CPP). Together, these results indicate that the fusion of SOD with these CPP increased the antioxidant capacity of fibroblasts, identified by the reduction in the generation of ROS. In addition, such molecules, in the concentrations initially used, were not toxic to the cells, opening perspectives for the development of products for antioxidant protection of the skin that may have therapeutic and cosmetic application.

Awareness and Knowledge of the Effect of Ultraviolet (UV) Radiation on the Eyes and the Relevant Protective Practices: A Cross-Sectional Study from Jordan

Background: Overexposure to ultraviolet (UV) radiation is linked to serious adverse health effects that are cumulative in nature and affect children more than adults. UV radiation has also been reported to have serious complications for the eye, particularly in areas with a high UV radiation index. Increasing public awareness about the harmful effects of UV radiation on the eye and promoting awareness about protection against UV radiation may prevent eye disease related to UV radiation damage and help in the improvement of public health in general. This study aims to assess public awareness and knowledge of UV radiation and practices toward UV protection in Jordan, which is a country recognized as having a relatively high UV index throughout the year. Methods: A cross-sectional study was performed using an online questionnaire using Google Forms^® to assess people's awareness, knowledge, practices toward eye protection from UV radiation, and the reasons for not wearing UV-protective eyeglasses in Jordan. Sociodemographic information of participants including age, gender, education level, and employment status was also acquired. People's knowledge on UV protection and harmfulness was measured via rewarding their correctly answered knowledge questions with one mark and zero for incorrectly answered questions based on key answers defined from the literature. Results: A total of 1331 participants (77% females and 23% males) with an average age of 26(±10) years completed the online questionnaire. Participants showed generally high levels of knowledge and awareness about UV radiation and its harmful effects. Nevertheless, participants showed a low level of knowledge about the link between UV radiation and some of the ocular diseases in the questionnaire. Practices toward UV radiation protection where inadequate, with 59% of the respondents reporting that they do not use any protective eyewear from natural UV radiation. The main reported reason for not wearing UV-protective sunglasses was uncertainty in the efficiency of UV protection in sunglasses, as reported by 47% of the participants who do not wear UV-protective sunglasses. Conclusions: The awareness of UV radiation and its harmful effects is high in the studied population. Participant knowledge is also relatively high in relation to nature of solar UV radiation, other synthetic sources of UV radiation, and the most dangerous UV exposure time. However, low participant knowledge was measured on the association between UV radiation with ocular disease and the role of UV-protective eyeglasses. Participant practice toward UV radiation protection was found to be insufficient. Thus, it is important to further increase the knowledge of damaging effects of solar and synthetic UV radiation and emphasize the benefits of eye protection from UV radiation. Eye care practitioners should target youth by different strategies including health campaigns, media, and clinics.

Curcumin Improves Keratinocyte Proliferation, Inflammation, and Oxidative Stress through Mediating the SPAG5/FOXM1 Axis in an In Vitro Model of Actinic Dermatitis by Ultraviolet

Background

Chronic actinic dermatitis (CAD) is an abnormally proliferating photoallergic skin disease. Dysregulated inflammation and oxidative stress are the immediate factors in the abnormal proliferation of keratinocytes. This study aimed to investigate the effect of curcumin on the aberrant proliferation of keratinocytes in an in vitro (actinic dermatitis) AD model and the possible molecular mechanisms.

Methods

The keratinocytes were irradiated with ultraviolet (UV) to construct an in vitro AD model and then processed with different concentrations of curcumin. Cell viability, oxidative stress markers (SOD, GSH-PX, and MDA), activated oxygen species (ROS), and inflammation markers (IL-1β, IL-6, IL-18, and TNFα) were determined, respectively. Western blot was applied to assay the profiles of apoptosis-related proteins (Bax, Bcl-xL, Caspase3, Caspase8, and Caspase9), oxidative stress proteins (Keap1, Nrf2, HO-1, COX2, and iNOS), and inflammatory proteins (NF-κB, MMP1, and MMP9) and SPAG5/FOXM1. Functionally, SPAG5 or FOXM1 overexpression and knockdown models were constructed in keratinocytes to characterize their influence on UV irradiation-mediated keratinocyte dysfunction.

Results

Curcumin weakened UV-mediated inflammation, proliferation, and oxidative stress and impaired apoptosis in keratinocytes. UV boosted SPAG5/FOXM1 expression in cells, while curcumin concentration-dependently retarded SPAG5/FOXM1 expression. Overexpression of SPAG5/FOXM1 fostered UV-mediated inflammation, proliferation, oxidative stress, and intensified apoptosis, whereas curcumin mostly reversed the SPAG5/FOXM1-mediated effects. In addition, knocking down SPAG5/FOXM1 ameliorated UV-mediated keratinocyte dysfunction, whereas curcumin failed to exert further protective effects in cells with knockdown of SPAG5/FOXM1.

Conclusion

Curcumin modulated proliferation, inflammation, oxidative stress, and apoptosis of keratinocytes by restraining the SPAG5/FOXM1 axis.

Worenine Prevents Solar Ultraviolet–Induced Sunburn by Inhibiting JNK2

Excessive solar ultraviolet (SUV) radiation often causes dermatitis, photoaging, and even skin cancer. In the pathological processes of SUV-induced sunburn, JNK is activated by phosphorylation, and it in turn phosphorylates its downstream transcription factors, such as ATF2 and c-jun. The transcription factors further regulate the expression of pro-inflammatory genes, such as IL-6 and TNF-α, which ultimately leads to dermatitis. Therefore, inhibiting JNK may be a strategy to prevent dermatitis. In this study, we screened for worenine as a potential drug candidate for inhibiting sunburn. We determined that worenine inhibited the JNK-ATF2/c-jun signaling pathway and the secretion of IL-6 and TNF-α in cell culture and in vivo, confirming the role of worenine in inhibiting sunburn. Furthermore, we determined that worenine bound and inhibited JNK2 activity in vitro through the MST, kinase, and in vitro kinase assays. Therefore, worenine might be a promising drug candidate for the prevention and treatment of SUV-induced sunburn.

Optical Behavior of Human Skin Substitutes: Absorbance in the 200-400 nm UV Range

The most recent generation of bioengineered human skin allows for the efficient treatment of patients with severe skin defects. Despite UV sunlight can seriously affect human skin, the optical behavior in the UV range of skin models is still unexplored. In the present study, absorbance and transmittance of the UGRSKIN bioartificial skin substitute generated with human skin cells combined with fibrin-agarose biomaterials were evaluated for: UV-C (200−280 nm), -B (280−315 nm), and -A (315−400 nm) spectral range after 7, 14, 21 and 28 days of ex vivo development. The epidermis of the bioartificial skin substitute was able to mature and differentiate in a time-dependent manner, expressing relevant molecules able to absorb most of the incoming UV radiation. Absorbance spectral behavior of the skin substitutes showed similar patterns to control native skin (VAF > 99.4%), with values 0.85−0.90 times lower than control values at 7 and 14- days and 1.05−1.10 times the control values at 21- and 28-days. UV absorbance increased, and UV transmission decreased with culture time, and comparable results to the control were found at 21 and 28 days. These findings support the use of samples corresponding to 21 or 28 days of development for clinical purposes due to their higher histological similarities with native skin, but also because of their absorbance of UV radiation.

Umbilicaria esculenta Extract Exhibits Antiwrinkle Activity by Suppressing ErbB2 Phosphorylation

Umbilicaria esculenta (UE), an edible lichen, is widespread in northeast Asian countries, including China, Japan, and Korea. In the present study, we examined the antiwrinkle activity of UE. We observed that the UE extract (UEE) suppressed ultraviolet (UV)-induced matrix metalloprotein-1 (MMP-1) expression and reactive oxygen species (ROS) generation in a human keratinocyte cell line (HaCaT) and human skin tissue. In addition, UEE reversed the UV-induced decrease in collagen in the human skin tissue. Excessive and chronic UV exposure is a key factor underlying skin wrinkle formation via MMP-1 expression. As treatment with UEE disrupted the UV-activated mitogen-activated protein kinase (MAPK) signaling pathway, we applied an antibody array to unveil the underlying mechanism of UEE. Interestingly, UEE treatment inhibited ErbB2 phosphorylation, but not epidermal growth factor receptor phosphorylation, a heterodimerization partner with ErbB2. Furthermore, UEE treatment enhanced UV-suppressed phosphatase activity via ROS suppression. Collectively, our findings indicate that UEE enhances ErbB2 dephosphorylation to suppress UV-induced MMP-1 expression.

A Cosmeceutical Topical Water-in-Oil Nanoemulsion of Natural Bioactives: Design of Experiment, in vitro Characterization, and in vivo Skin Performance Against UVB Irradiation-Induced Skin Damages

Introduction

Damage to human skin occurs either chronologically or through repetitive exposure to ultraviolet (UV) radiation, where collagen photodegradation leads to the formation of wrinkles and skin imperfections. Consequently, cosmeceutical products containing natural bioactives to restore or regenerate collagen have gained a remarkable attention as an ameliorative remedy.

Methods

This study aimed to develop and optimize collagen-loaded water-in-oil nanoemulsion (W/O NE) through a D-optimal mixture design to achieve an ideal multifunctional nanosystem containing active constituents. Vit E was included as a constituent of the formulation for its antioxidant properties to minimize the destructive impact of UV radiation. The formulated systems were characterized in terms of their globule size, optical clarity, and viscosity. An optimized system was selected and evaluated for its physical stability, in vitro wound healing properties, and in vivo permeation and protection against UV radiation. In addition, the effect of collagen-loaded NE was compared to Vit C-loaded NE and collagen-/Vit C-loaded NEs mixture as Vit C is known to enhance collagen production within the skin.

Results

The optimized NE was formulated with 25% oils (Vit E: safflower oil, 1:3), 54.635% surfactant/cosurfactant (Span 80: Kolliphor EL: Arlasolve, 1:1:1), and 20.365% water. The optimized NE loaded with either collagen or Vit C exhibited a skin-friendly appearance with boosted permeability, and improved cell viability and wound healing properties on fibroblast cell lines. Moreover, the in vivo study and histopathological investigations confirmed the efficacy of the developed system to protect the skin against UV damage. The results revealed that the effect of collagen-/Vit C-loaded NEs mixture was more pronounced, as both drugs reduced the skin damage to an extent that it was free from any detectable alterations.

Conclusion

NE formulated using Vit E and containing collagen and/or Vit C could be a promising ameliorative remedy for skin protection against UVB irradiation.

An Exploration of How Solar Radiation Affects the Seasonal Variation of Human Mortality Rates and the Seasonal Variation in Some Other Common Disorders

Many diseases have large seasonal variations in which winter overall mortality rates are about 25% higher than in summer in mid-latitude countries, with cardiovascular diseases and respiratory infections and conditions accounting for most of the variation. Cancers, by contrast, do not usually have pronounced seasonal variations in incidence or mortality rates. This narrative review examines the epidemiological evidence for seasonal variations in blood pressure, cardiovascular disease rates and respiratory viral infections in relation to atmospheric temperature and humidity, and solar UV exposure through vitamin D production and increased blood concentrations of nitric oxide. However, additional mechanisms most likely exist by which solar radiation reduces the risk of seasonally varying diseases. Some studies have been reported with respect to temperature without considering solar UV doses, although studies regarding solar UV doses, such as for respiratory infections, often consider whether temperature can affect the findings. More research is indicated to evaluate the relative effects of temperature and sun exposure on the seasonality of mortality rates for several diseases. Since solar ultraviolet-B (UVB) doses decrease to vanishingly small values at higher latitudes in winter, the use of safe UVB lamps for indoor use in winter may warrant consideration.

Anti-Photoaging Activity of Scutellaria barbata D. Don (Family Lamiaceae) on Ultraviolet B-Irradiated NIH-3T3 Skin Fibroblast and SKH-1 Hairless Mouse

We investigated whether Scutellaria barbata D. Don (Family Lamiaceae) (SBD), a traditional medicine used for heat clearing and detoxification, possesses antiphotoaging properties. Pretreatment of NIH-3T3 skin fibroblast cells with non-toxicological levels of water extract of SBD (WESBD) and ethanol extract of SBD (EESBD) restored the expression of procollagen type-1 (COL1A1), matrix metalloproteinase-1a (MMP-1a), interleukin-6 (IL-6), interleukin-8 (IL-8), and monocyte chemotactic protein-3 (MCP-3) genes following abnormal expression induced by ultraviolet B (UVB) irradiation. WESBD/EESBD administration to the dorsal skin area of hairless mice significantly (p < 0.05) inhibited UVB-induced wrinkle formation and epidermal thickness. The WESBD and EESBD treatments also restored the dermal collagen content, which was decreased by the UVB treatment, and normal COL1A1 and MMP-1a expression. Interestingly, both the WESBD and EESBD pretreatments significantly attenuated UVB-induced phosphorylation of protein kinase B (AKT) but not that of mitogen-activated protein kinases (MAPKs). This finding indicates that the antiphotoaging effects of WESBD and EESBD may be related to attenuation of UVB-induced overactivation of AKT phosphorylation. High performance liquid chromatography (HPLC) and mass spectrometry analysis revealed that isorhamentin and scutebarbatine I were major single components of EESBD. These results suggest that WESBD and EESBD may have potential in development as antiphotoaging agents.

New insights from non-invasive imaging: from prospection of skin photodamages to training with mobile application

The incidence of non‐melanoma skin cancer is on the rise and melanoma is among the most common cancers in the United States. Establishing an early diagnosis is essential for improving the prognosis of patients with skin cancer. High‐resolution non‐invasive imaging techniques may represent key tools for helping to identify and monitor early signs of skin cancer in seemingly healthy skin. Cumulative lifetime sun exposure leads to photoaging and photocarcinogenenis and the reaction of the skin to this solar‐induced damage is balanced between the DNA repair and photoprotection defence mechanisms of melanocytes and keratinocytes. In the first part of this article we provide an overview of these defence mechanisms and of the photoaging process, and discuss how non‐invasive imaging can be used to evaluate these changes. We then propose a model in which skin aging manifestations can be classified according to subject‐specific sun‐damage reaction profiles observed by reflectance confocal microscopy (RCM) and optical coherence tomography (OCT). These photoaging profiles include an atrophic phenotype characterized by actinic keratosis, and a hypertrophic phenotype characterized by hyperplastic pigmented skin. According to our model, these phenotypes may be predictive of predispositions to different types of skin cancer: squamous cell carcinoma for the atrophic phenotype and lentigo maligna and freckles for the hypertrophic phenotype. In addition to RCM and OCT, dermoscopy is another non‐invasive technique that has improved the diagnosis of skin cancer. In the second part of this article, we describe how the YouDermoscopy™ application can improve skills and thus enhance the dermoscopic recognition of sun‐induced skin tumours, and then show how this training tool enables its users to collaborate with dermatologists worldwide to obtain second opinions for the diagnosis of ambiguous lesions. Altogether, RCM, OCT and dermoscopy are valuable tools that can contribute significantly to improving the early diagnosis of precancerous and cancerous lesions.

Labdanum Resin from Cistus ladanifer L.: A Natural and Sustainable Ingredient for Skin Care Cosmetics with Relevant Cosmeceutical Bioactivities

Labdanum resin from Cistus ladanifer L. (Cistaceae) is an abundant natural resource in the Iberian Peninsula worth being explored in a sustainable manner. It is already used in the cosmetic industry; mainly by the fragrances/perfumery sector. However, given the highest market share and traditional uses, labdanum resin also has the potential to be used and valued as a cosmetic ingredient for skincare. Aiming to evaluate this potential, labdanum methanolic absolute and fractions purified by column chromatography were characterized by UPLC-DAD-ESI-MS and then evaluated for UV-protection, antioxidant, anti-elastase, anti-inflammatory, and antimicrobial activities. Labdanum absolute represented ~70% of the resin; diterpenoid and flavonoid fractions represented ~75% and 15% of the absolute, respectively. Labdane-type diterpenoids and methylated flavonoids were the main compounds in labdanum absolute and in diterpenoid and flavonoid fractions, respectively. Labdanum absolute showed a spectrophotometric sun protection factor (SPF) near 5, which is mainly due to flavonoids, as the flavonoids’ SPF was 13. Low antioxidant activity was observed, with ABTS radical scavenging being the most significant (0.142 ± 0.017, 0.379 ± 0.039 and 0.010 ± 0.003 mgTE/mgExt, for the absolute and flavonoid and terpene fractions, respectively). Anti-aging and anti-inflammatory activity are reported here for the first time, by the inhibition of elastase activity (22% and 13%, by absolute and flavonoid extract at 1 mg/mL), and by the inhibition of nitric oxide production in LPS-induced RAW 264.7 cells (84% to 98%, at 15 µg/mL extracts, flavonoid fraction the most active), respectively. Antimicrobial activity, against relevant skin and cosmetic product microorganisms, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Escherichia coli, revealed that only S. aureus was susceptible to labdanum absolute (MIC: 1.2 mg/mL) and its fractions (MIC: <0.3 mg/mL). In conclusion, labdanum resin showed potential to be used in sunscreen cosmetics, anti-inflammatory skincare cosmeceuticals or medicines but has low potential as a cosmetic product preservative given the low antioxidant and low-spectrum antimicrobial activities.

Self-Adhesive and Antioxidant Poly(vinylpyrrolidone)/Alginate-Based Bilayer Films Loaded with Malva sylvestris Extracts as Potential Skin Dressings

Malva sylvestris (MS) is a medicinal herb known worldwide for its beneficial effects due to the several active molecules present in its leaves and flowers. These compounds have shown antioxidant and anti-inflammatory properties and thus can be helpful in treatments of burns and chronic wounds, characterized mainly by high levels of free radicals and impairments of the inflammatory response. In this work, we propose bilayer films as wound dressings, based on poly(vinylpyrrolidone) (PVP) and sodium alginate loaded with M. sylvestris extracts from leaves and flowers and fabricated by combining solvent-casting and rod-coating methods. The top layer is produced in two different PVP/alginate ratios and loaded with the MS flowers' extract, while the bottom layer is composed of PVP and MS leaves' extract. The bilayers were characterized morphologically, chemically, and mechanically, while they showed superior self-adhesive properties on human skin compared to a commercial skin patch. The materials showed antioxidant activity, release of the bioactive compounds, and water uptake property. Moreover, the anthocyanin content of the flower extract provided the films with the ability to change color when immersed in buffers of different pH levels. In vitro tests using primary keratinocytes demonstrated the biocompatibility of the MS bilayer materials and their capacity to enhance the proliferation of the cells in a wound scratch model. Finally, the best performing MS bilayer sample with a PVP/alginate ratio of 70:30 was evaluated in mice models, showing suitable resorption properties and the capacity to reduce the level of inflammatory mediators in UVB-induced burns when applied to an open wound. These outcomes suggest that the fabricated bilayer films loaded with M. sylvestris extracts are promising formulations as active and multifunctional dressings for treating skin disorders.

Non-Melanoma Skin Cancer: A Genetic Update and Future Perspectives

Simple Summary

Non-melanoma skin cancer (NMSC) is the main type of cancer in the Caucasian population, and the number of cases continues to rise. Research mostly focuses on clinical characteristics analysis, but genetic features are crucial to malignancies’ establishment and advance. We aim to explore the genetic basics of skin cancer, surrounding microenvironment interactions, and regulation mechanisms to provide a broader perspective for new therapies’ development.

Abstract

Skin cancer is one of the main types of cancer worldwide, and non-melanoma skin cancer (NMSC) is the most frequent within this group. Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are the most common types. Multifactorial features are well-known for cancer development, and new hallmarks are gaining relevance. Genetics and epigenetic regulation play an essential role in cancer susceptibility and progression, as well as the variety of cells and molecules that interact in the tumor microenvironment. In this review, we provide an update on the genetic features of NMSC, candidate genes, and new therapies, considering diverse perspectives of skin carcinogenesis. The global health situation and the pandemic have been challenging for health care systems, especially in the diagnosis and treatment of patients with cancer. We provide innovative approaches to overcome the difficulties in the current clinical dynamics.

Proteomic Response Revealed Signaling Pathways Involving in the Mechanism of Polymyxin B-Induced Melanogenesis

Polymyxin B is a last-line antibiotic for extensively resistant Gram-negative bacterial infection. Skin hyperpigmentation is a serious side effect induced by polymyxin B that severely compromises the psychological health and compliance of patients. The literature lacks mechanistic studies that explain how hyperpigmentation occurs, and this substantially hinders the development of intervention strategies and improved compliance. SK-MEL-2 cells were used for the polymyxin B-induced hyperpigmentation mechanism study. Melanin content and tyrosinase activity were measured after polymyxin B treatment. Tandem mass tag (TMT)-labeling quantitative proteomics was employed to investigate the response of SK-MEL-2 cells to polymyxin B treatment. Real-time quantitative PCR and Western blot were applied to validate the mRNA and protein levels of related genes and proteins. The melanin content and tyrosinase activity were significantly upregulated after polymyxin B treatment in SK-MEL-2 cells at 48 h and 72 h. Quantitative proteomics showed that 237 proteins were upregulated and 153 proteins were downregulated in the 48 h group, and 49 proteins were upregulated and 49 proteins were downregulated in the 72 h group. The differentially expressed proteins were involved in pathways such as lysosome, PI3K/Akt signaling pathway, and calcium signaling pathway. The upregulation of melanogenic enzymes and microphthalmia-associated transcription factor (MITF) was validated by qPCR and Western blot. Meanwhile, phosphorylation of PI3K, β-catenin, and cyclic-AMP response binding protein (CREB) in response to polymyxin B treatment was observed. The present study reveals the proteomic response of polymyxin B-induced melanogenesis in SK-MEL-2 cells for the first time. Signaling pathways, including melanin biosynthesis, PI3K/Akt, and calcium signaling pathways may be involved in the mechanism of melanogenesis. IMPORTANCE Polymyxin B-induced skin hyperpigmentation seriously affects the psychological health and compliance of patients. This study provides a proteomic clue to the mechanism at the cellular level for understanding polymyxin B-induced hyperpigmentation, contributing to a follow-up investigation of the corresponding PI3K/Akt signaling transduction pathway and calcium signaling pathway. The elucidation of its underlying mechanism is of great significance for patients' compliance improvement, intervention strategy, and new drug development.

Melanin and Melanin-Functionalized Nanoparticles as Promising Tools in Cancer Research-A Review

Cancer poses an ongoing global challenge, despite the substantial progress made in the prevention, diagnosis, and treatment of the disease. The existing therapeutic methods remain limited by undesirable outcomes such as systemic toxicity and lack of specificity or long-term efficacy, although innovative alternatives are being continuously investigated. By offering a means for the targeted delivery of therapeutics, nanotechnology (NT) has emerged as a state-of-the-art solution for augmenting the efficiency of currently available cancer therapies while combating their drawbacks. Melanin, a polymeric pigment of natural origin that is widely spread among many living organisms, became a promising candidate for NT-based cancer treatment owing to its unique physicochemical properties (e.g., high biocompatibility, redox behavior, light absorption, chelating ability) and innate antioxidant, photoprotective, anti-inflammatory, and antitumor effects. The latest research on melanin and melanin-like nanoparticles has extended considerably on many fronts, allowing not only efficient cancer treatments via both traditional and modern methods, but also early disease detection and diagnosis. The current paper provides an updated insight into the applicability of melanin in cancer therapy as antitumor agent, molecular target, and delivery nanoplatform.

Reversibly immortalized keratinocytes (iKera) facilitate re-epithelization and skin wound healing: Potential applications in cell-based skin tissue engineering

Skin injury is repaired through a multi-phase wound healing process of tissue granulation and re-epithelialization. Any failure in the healing process may lead to chronic non-healing wounds or abnormal scar formation. Although significant progress has been made in developing novel scaffolds and/or cell-based therapeutic strategies to promote wound healing, effective management of large chronic skin wounds remains a clinical challenge. Keratinocytes are critical to re-epithelialization and wound healing. Here, we investigated whether exogenous keratinocytes, in combination with a citrate-based scaffold, enhanced skin wound healing. We first established reversibly immortalized mouse keratinocytes (iKera), and confirmed that the iKera cells expressed keratinocyte markers, and were responsive to UVB treatment, and were non-tumorigenic. In a proof-of-principle experiment, we demonstrated that iKera cells embedded in citrate-based scaffold PPCN provided more effective re-epithelialization and cutaneous wound healing than that of either PPCN or iKera cells alone, in a mouse skin wound model. Thus, these results demonstrate that iKera cells may serve as a valuable skin epithelial source when, combining with appropriate biocompatible scaffolds, to investigate cutaneous wound healing and skin regeneration.

Effect of Ultraviolet B Irradiation on Melanin Content Accompanied by the Activation of p62/GATA4-Mediated Premature Senescence in HaCaT Cells

Objective

To explore the effect and mechanism of ultraviolet B (UVB) on melanin synthesis and premature senescence in human immortalized keratinocytes (HaCaT) cells.

Methods

HaCaT cells were irradiated with 0, 20, 50, 80, 100, 150, and 200 mJ/cm2 of UVB. NaOH method was used for melanin content assay, cellular tyrosinase (TYR) activity was determined by 3,4-Dihydroxy-L-phenylalanine (L-DOPA) oxidation to dopachrome, premature senescence was analyzed by senescence-associated beta-galactosidase (SA-β-gal) staining kit, and the levels of p21, p16, p62, and GATA4 proteins were detected by Western blotting. Premature senescence was inhibited by the inhibitors of ataxia telangiectasia mutated (ATM) or ataxia telangiectasia and Rad3–related (ATR), and the p53 signaling pathway was activated by Nutlin-3. The mRNA levels of senescence-associated secretory phenotype (SASP) factors including tumor necrosis factor alpha (TNF-α), vascular endothelial growth factor A (VEGF-A), and interleukin-8 (IL-8) were measured by real-time quantitative polymerase chain reaction in HaCaT cells after 80 mJ/cm2 of UVB irradiation.

Results

The melanin level increased significantly with the elevation of irradiation dose ( F = 28.19, 43.82, 143.60, P < .05), reaching the peak at the dose of 80 mJ/cm2. The tyrosinase activity increased significantly ( F = 84.50, P < .05), the percentage of premature senescence increased ( F = 16.31, P < .05), the levels of p62 decreased, and the level of GATA4 increased obviously with the increase of UVB dose after irradiation. The UVB-induced promotion of GATA4 level was significantly inhibited by being treated with ATM or ATR inhibitor. However, this did not occur in the Nutlin-3-treated group. The mRNA and protein expression of TNF-α increased significantly at 72 h at 80 mJ/cm2 of UVB irradiation.

Conclusions

Melanin contents increased first and decreased afterward with the increasing of UVB irradiation. The decrease of p62-mediated selective autophagy was accompanied by the accumulation of GATA4 after different doses of UVB irradiation. Activation of this p62/GATA4 pathway depends on the ATM and ATR but is independent of p53, and the SASP factor was activated in HaCaT cells at 80 mJ/cm2 of UVB irradiation.

Dual Skin-Whitening and Anti-wrinkle Function of Low-Molecular-Weight Fish Collagen

In this study, we investigated the protective effects of low-molecular-weight fish collagen from tilapia against melanogenesis in melanocytes, ultraviolet B (UVB)-irradiated Hs27 skin fibroblasts, and hairless mice. We observed collagen production-related pathways in UVB-irradiated Hs27 skin fibroblasts and hairless mice, and the melanogenesis-related pathways in melanocyte and UVB-irradiated hairless mice. The collagen production-related pathways were activated in the UVB-irradiated Hs27 skin fibroblasts and hairless mice. In addition, UVB exposure stimulated the melanogenesis-related pathways in melanocytes and hairless mice. However, treatment with low-molecular-weight fish collagen significantly increased the messenger RNA expressions of collagen production-related factors and significantly decreased the production of cytokines. Furthermore, treatment with low-molecular-weight fish collagen suppressed melanogenesis by inhibiting glutathione synthesis and downregulating melanocyte-inducing transcription factor expression through the suppression of cyclic AMP/protein kinase A/cAMP-responsive binding protein signaling and nitric oxide production. Low-molecular-weight fish collagen exerts protective effects against UVB-induced photoaging, through anti-inflammatory, antioxidant, and anti-melanogenesis activities and could be used for developing effective natural anti-photoaging products.