Particulate matter-induced atmospheric skin aging is aggravated by UVA and inhibited by a topical l-ascorbic acid compound

UVB-induced TRPS1 regulates MITF transcription activity to promote skin pigmentation

Hyperpigmented dermatoses are characterized by increased skin pigmentation caused by genetic, environmental factors and inflammation, which lasts a long time and is difficult to treat. Ultraviolet (UV), especially ultraviolet B (UVB), is the primary external factor inducing skin pigmentation. However, the specific regulatory mechanisms are not fully understood. Through analysis of GEO datasets from four UV-exposed skin cell/tissue samples, we found that TRPS1 is the only gene differentially expressed in multiple datasets (GSE22083, GSE67098 and GSE70280) and highly positively correlated with the expression of key melanogenesis genes. Consistently, we observed that TRPS1 is highly expressed in sun-exposed skin tissues compared to non-exposed skin. Additionally, the expression of TRPS1 was also significantly upregulated after UVB irradiation in isolated skin tissues and melanocytes, while knockdown of TRPS1 expression inhibited the UVB-induced melanogenesis. Further research revealed that overexpression of TRPS1 increased melanin content and tyrosinase activity in MNT1 cells, as well as upregulated the expression levels of key melanogenesis genes (MITF, TYR, TYRP1, DCT). In contrast, inhibition of TRPS1 expression showed the opposite effect. Moreover, we found that TRPS1 can bind to the promoter region of MITF, inhibiting the expression of MITF can antagonize the melanogenesis induced by TRPS1. In conclusion, UVB-induced TRPS1 promotes melanogenesis by activating the transcriptional activity of MITF.

Assessment of cellular senescence potential of PM2.5 using 3D human lung fibroblast spheroids in vitro model

Background

Epidemiological studies demonstrate that particulate matter 2.5 (PM2.5) exposure closely related to chronic respiratory diseases. Cellular senescence plays an important role in many diseases. However, it is not fully clear whether PM2.5 exposure could induce cellular senescence in the human lung. In this study, we generated a three-dimensional (3D) spheroid model using isolated primary human lung fibroblasts (HLFs) to investigate the effects of PM2.5 on cellular senescence at the 3D level.

Methods

3D spheroids were exposed to 25-100 μg/ml of PM2.5 in order to evaluate the impact on cellular senescence. SA-β-galactosidase activity, cell proliferation, and the expression of key genes and proteins were detected.

Results

Exposure of the HLF spheroids to PM2.5 yielded a more sensitive cytotoxicity than 2D HLF cell culture. Importantly, PM2.5 exposure induced the rapid progression of cellular senescence in 3D HLF spheroids, with a dramatically increased SA-β-Gal activity. In exploiting the mechanism underlying the effect of PM2.5 on senescence, we found a significant increase of DNA damage, upregulation of p21 protein levels, and suppression of cell proliferation in PM2.5-treated HLF spheroids. Moreover, PM2.5 exposure created a significant inflammatory response, which may be at least partially associated with the activation of TGF-β1/Smad3 axis and HMGB1 pathway.

Conclusions

Our results indicate that PM2.5 could induce DNA damage, inflammation, and cellular senescence in 3D HLF spheroids, which may provide a new evidence for PM2.5 toxicity based on a 3D model which has been shown to be more in vivo-like in their phenotype and physiology than 2D cultures.

Assessment of potential ecological risk for polycyclic aromatic hydrocarbons in urban soils with high level of atmospheric particulate matter concentration

Polycyclic aromatic hydrocarbons (PAHs) are known to be representative carcinogenic environmental pollutants with high toxicity. However, information on the potential ecological and environmental risks of PAH contamination in soil remains scarce. Thus, this study was evaluated the potential ecological risks of PAHs in soils of five Korean areas (Gunsan (GS), Gwangju, Yeongnam, Busan, and Gangwon) using organic carbon (OC)-normalized analysis, mean effect range-median quotient (M-ERM-Q), toxic equivalent quantity (TEQ) analysis, and risk quotient (RQ) derived by the species sensitivity distribution model. In this study, atmospheric particulate matter has a significant effect on soil pollution in GS through the presence of hopanes and the similar pattern of PAHs in soil and atmospheric PAHs. From analysis of source identification, combustion sources in soils of GS were important PAH sources. For PAHs in soils of GS, the OC-normalized analysis, M-ERM-Q, and TEQ analysis have 26.78 × 105 ng/g-OC, 0.218, and 49.72, respectively. Therefore, the potential ecological risk assessment results showed that GS had moderate-high ecological risk and moderate-high carcinogenic risk, whereas the other regions had low ecological risk and low-moderate carcinogenic risk. The risk level (M-ERM-Q) of PAH contamination in GS was similar to that in Changchun and Xiangxi Bay in China. The Port Harcourt City in Nigeria for PAH has the highest risk (M-ERM-Q = 4.02 and TEQ = 7923). Especially, compared to China (RQPhe =0.025 and 0.05), and Nigeria (0.059), phenanthrene showed the highest ecological risk in Korea (0.001-0.18). Korea should focus on controlling the release of PAHs originating from the PM in GS.

In Vitro Profiling of Toxicity Effects of Different Environmental Factors on Skin Cells

The skin is constantly exposed to a variety of environmental threats. Therefore, the influence of environmental factors on skin damage has always been a matter of concern. This study aimed to investigate the cytotoxic effects of different environmental factors, including cooking oil fumes (COFs), haze (PM2.5), and cigarette smoke (CS), on epidermal HaCaT cells and dermal fibroblast (FB) cells. Cell viability, intracellular reactive oxygen species (ROS) generation, inflammatory cytokine levels, and collagen mRNA expression were used as toxicity endpoints. Additionally, the effects of ozone (O3) on cell viability and release of inflammatory cytokines in 3D epidermal cells were also examined. The results showed that the organic extracts of CS, COFs, and PM2.5 significantly inhibited the viability of HaCaT and FB cells at higher exposure concentrations. These extracts also increased intracellular ROS levels in FB cells. Furthermore, they significantly promoted the release of inflammatory cytokines, such as IL-1α and TNF-α, in HaCaT cells and down-regulated the mRNA expression of collagen I, III, IV, and VII in FB cells. Comparatively, SC organic extracts exhibited stronger cytotoxicity to skin cells compared to PM2.5 and COFs. Additionally, O3 at all test concentrations significantly inhibited the viability of 3D epidermal cells in a concentration-dependent manner and markedly increased the levels of TNF-α and IL-1α in 3D epidermal cells. These findings emphasize the potential cytotoxicity of COFs, PM2.5, CS, and O3 to skin cells, which may lead to skin damage; therefore, we should pay attention to these environmental factors and take appropriate measures to protect the skin from their harmful effects.

Can l-ascorbic acid and trans-resveratrol protect HaCaT cells from fine particulate matter toxicity?

Continuous exposure of human skin to air pollution can result in a range of undesirable skin conditions. In our recent study, UV and visible light were found to increase cytotoxicity of fine particulate matter (PM2.5 ) against human keratinocytes. Since it is impossible to avoid exposure of human skin to PM2.5 , effective strategies are needed to reduce their damaging effects. l-ascorbic acid and resveratrol were tested as potential topical agents against pollution-related skin impairment. Although these agents were previously found to ameliorate PM-dependent damage, the effect of light and seasonal variation of particles were not previously studied. EPR spin-trapping, DPPH assay, and singlet oxygen phosphorescence were used to determine the scavenging activities of the antioxidants. MTT, JC-10 and iodometric assays were used to analyze the effect on PM2.5 -induced cytotoxicity, mitochondrial damage and oxidation of lipids. Live-cell imaging was employed to examine wound-healing properties of cells. Light-induced, PM2.5 -mediated oxidative damage was examined by immunofluorescent staining. Both antioxidants effectively scavenged free radicals and singlet oxygen produced by PM2.5 , reduced cell death and prevented oxidative damage to HaCaT cells. l-ascorbic acid and resveratrol, especially when applied in combination, can protect HaCaT cells against the dark and light induced toxicity of PM2.5 .

Production of Antioxidant Transfersomes by a Supercritical CO2 Assisted Process for Transdermal Delivery Applications

Transfersomes are deformable vesicles that can transport drugs across difficult-to-permeate barriers in human tissues. In this work, nano-transfersomes were produced for the first time by a supercritical CO₂ assisted process. Operating at 100 bar and 40 °C, different amounts of phosphatidylcholine (2000 and 3000 mg), kinds of edge activators (Span^® 80 and Tween^® 80), and phosphatidylcholine to edge activator weight ratio (95:5, 90:10, 80:20) were tested. Formulations prepared using Span^® 80 and phosphatidylcholine at an 80:20 weight ratio produced stable transfersomes (-30.4 ± 2.4 mV ζ-potential) that were characterized by a mean diameter of 138 ± 55 nm. A prolonged ascorbic acid release of up to 5 h was recorded when the largest amount of phosphatidylcholine (3000 mg) was used. Moreover, a 96% ascorbic acid encapsulation efficiency and a quasi-100% DPPH radical scavenging activity of transfersomes were measured after supercritical processing.

The role of cytokines/chemokines in an aging skin immune microenvironment

Reversing or slowing down the skin aging process is one of the most intriguing areas of focus across the social and scientific communities around the world. While aging is considered a universal and inevitable natural process of physiological decline, the aging of the skin is the most apparent visual representation of an individual's health. Aging skin may be objectively defined by epidermal thinning; increased transepidermal water loss; decreased cutaneous barrier function; loss of elasticity, laxity, and textured appearance; and gradual deterioration of the epidermal immune environment. As the largest structure of the immune system and of the body as a whole, the skin is the most vulnerable barrier of defense against the environment. The skin reflects an individual's exposures, lifestyle habits, and overall health. From an immunological perspective, cytokines and chemokines act as a central character in the communicating of the immunity in skin aging. These cell signaling proteins serve as the intercellular communication link. This review aims to elucidate how cell-cell crosstalk through cytokines and chemokines, and the interplay between host cells, infiltrating immune cells, and exogenous factors contribute to the overall aging skin.

Ascorbic Acid (Vitamin C) as a Cosmeceutical to Increase Dermal Collagen for Skin Antiaging Purposes: Emerging Combination Therapies

Ascorbic acid (AA) is an essential nutrient and has great potential as a cosmeceutical that protects the health and beauty of the skin. AA is expected to attenuate photoaging and the natural aging of the skin by reducing oxidative stress caused by external and internal factors and by promoting collagen gene expression and maturation. In this review, the biochemical basis of AA associated with collagen metabolism and clinical evidence of AA in increasing dermal collagen and inhibiting skin aging were discussed. In addition, we reviewed emerging strategies that have been developed to overcome the shortcomings of AA as a cosmeceutical and achieve maximum efficacy. Because extracellular matrix proteins, such as collagen, have unique amino acid compositions, their production in cells is influenced by the availability of specific amino acids. For example, glycine residues occupy 1/3 of amino acid residues in collagen protein, and the supply of glycine can be a limiting factor for collagen synthesis. Experiments showed that glycinamide was the most effective among the various amino acids and amidated amino acids in stimulating collagen production in human dermal fibroblasts. Thus, it is possible to synergistically improve collagen synthesis by combining AA analogs and amino acid analogs that act at different stages of the collagen production process. This combination therapy would be useful for skin antiaging that requires enhanced collagen production.

Effects of Air Pollution on Cellular Senescence and Skin Aging

The human skin is exposed daily to different environmental factors such as air pollutants and ultraviolet (UV) light. Air pollution is considered a harmful environmental risk to human skin and is known to promote aging and inflammation of this tissue, leading to the onset of skin disorders and to the appearance of wrinkles and pigmentation issues. Besides this, components of air pollution can interact synergistically with ultraviolet light and increase the impact of damage to the skin. However, little is known about the modulation of air pollution on cellular senescence in skin cells and how this can contribute to skin aging. In this review, we are summarizing the current state of knowledge about air pollution components, their involvement in the processes of cellular senescence and skin aging, as well as the current therapeutic and cosmetic interventions proposed to prevent or mitigate the effects of air pollution in the skin.

The Role of Antioxidants in the Interplay between Oxidative Stress and Senescence

Cellular senescence is an irreversible state of cell cycle arrest occurring in response to stressful stimuli, such as telomere attrition, DNA damage, reactive oxygen species, and oncogenic proteins. Although beneficial and protective in several physiological processes, an excessive senescent cell burden has been involved in various pathological conditions including aging, tissue dysfunction and chronic diseases. Oxidative stress (OS) can drive senescence due to a loss of balance between pro-oxidant stimuli and antioxidant defences. Therefore, the identification and characterization of antioxidant compounds capable of preventing or counteracting the senescent phenotype is of major interest. However, despite the considerable number of studies, a comprehensive overview of the main antioxidant molecules capable of counteracting OS-induced senescence is still lacking. Here, besides a brief description of the molecular mechanisms implicated in OS-mediated aging, we review and discuss the role of enzymes, mitochondria-targeting compounds, vitamins, carotenoids, organosulfur compounds, nitrogen non-protein molecules, minerals, flavonoids, and non-flavonoids as antioxidant compounds with an anti-aging potential, therefore offering insights into innovative lifespan-extending approaches.