Mechanism of UVB-induced wrinkling of the skin: paracrine cytokine linkage between keratinocytes and fibroblasts leading to the stimulation of elastase

Inhibition of Photoaging by Anthocyanin Metabolites Derived from Rose Petal Extract

SCOPE

Rose petal extract (RPE) shows a significant antioxidant effect through its anthocyanin content. However, the mechanism underlying the anti-aging effects of orally administered RPE remains unclear. This study aims to describe the anti-aging effect and mechanism of action of orally administered RPE in ultraviolet (UV)B-induced skin aging.

METHODS AND RESULTS

This study evaluates the protein expression of collagen type I alpha 1 (COL1A1) and matrix metalloproteinase 1 (MMP-1) and the mRNA expression of hyaluronic synthase 2 (HAS2) in human dermal fibroblasts. In addition, the hyaluronidase and collagenase inhibitory activities of RPE are confirmed. To evaluate the anti-aging effects of RPE, SKH-1 hairless mice are administered RPE daily for 12 weeks. Wrinkle formation, transepidermal water loss (TEWL), and skin moisture loss induced by UVB irradiation are suppressed in the dorsal skin of SKH-1 hairless mice orally administered RPE. Oral administration of RPE suppresses UVB irradiation-induced collagen disruption and reduction of hyaluronic acid. To find the bioactive compound in the RPE, serum protocatechuic acid (PCA), an anthocyanin metabolite, is analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

CONCLUSION

Anthocyanins in RPE are metabolized to PCA in the body and circulated through the bloodstream to exhibit anti-aging effects on the skin.

Integrative analysis of RNA-sequencing and microarray for the identification of adverse effects of UVB exposure on human skin

Background

Ultraviolet B (UVB) from sunlight represents a major environmental factor that causes toxic effects resulting in structural and functional cutaneous abnormalities in most living organisms. Although numerous studies have indicated the biological mechanisms linking UVB exposure and cutaneous manifestations, they have typically originated from a single study performed under limited conditions.

Methods

We accessed all publicly accessible expression data of various skin cell types exposed to UVB, including skin biopsies, keratinocytes, and fibroblasts. We performed biological network analysis to identify the molecular mechanisms and identify genetic biomarkers.

Results

We interpreted the inflammatory response and carcinogenesis as major UVB-induced signaling alternations and identified three candidate biomarkers (IL1B, CCL2, and LIF). Moreover, we confirmed that these three biomarkers contribute to the survival probability of patients with cutaneous melanoma, the most aggressive and lethal form of skin cancer.

Conclusion

Our findings will aid the understanding of UVB-induced cutaneous toxicity and the accompanying molecular mechanisms. In addition, the three candidate biomarkers that change molecular signals due to UVB exposure of skin might be related to the survival rate of patients with cutaneous melanoma.

Aging in the dermis: Fibroblast senescence and its significance

Skin aging is characterized by changes in its structural, cellular, and molecular components in both the epidermis and dermis. Dermal aging is distinguished by reduced dermal thickness, increased wrinkles, and a sagging appearance. Due to intrinsic or extrinsic factors, accumulation of excessive reactive oxygen species (ROS) triggers a series of aging events, including imbalanced extracellular matrix (ECM) homeostasis, accumulation of senescent fibroblasts, loss of cell identity, and chronic inflammation mediated by senescence-associated secretory phenotype (SASP). These events are regulated by signaling pathways, such as nuclear factor erythroid 2-related factor 2 (Nrf2), mechanistic target of rapamycin (mTOR), transforming growth factor beta (TGF-β), and insulin-like growth factor 1 (IGF-1). Senescent fibroblasts can induce and accelerate age-related dysfunction of other skin cells and may even cause systemic inflammation. In this review, we summarize the role of dermal fibroblasts in cutaneous aging and inflammation. Moreover, the underlying mechanisms by which dermal fibroblasts influence cutaneous aging and inflammation are also discussed.

Anti-Photoaging Effects of Upcycled Citrus junos Seed Anionic Peptides on Ultraviolet-Radiation-Induced Skin Aging in a Reconstructed Skin Model

Side streams and byproducts of food are established sources of natural ingredients in cosmetics. In the present study, we obtained upcycled low-molecular-weight anionic peptides (LMAPs) using byproducts of the post-yuzu-juicing process by employing an enzyme derived from Bacillus sp. For the first time, we isolated anionic peptides less than 500 Da in molecular weight from Citrus junos TANAKA seeds via hydrolysis using this enzyme. The protective effect of LMAPs against UVR-induced photoaging was evaluated using a reconstructed skin tissue (RST) model and keratinocytes. The LMAPs protected the keratinocytes by scavenging intracellular reactive oxygen species and by reducing the levels of paracrine cytokines (IL-6 and TNF-α) in UVR (UVA 2 J/cm2 and UVB 15 mJ/cm2)-irradiated keratinocytes. Additionally, the increase in melanin synthesis and TRP-2 expression in RST caused by UVR was significantly inhibited by LMAP treatment. This treatment strongly induced the expression of filaggrin and laminin-5 in UVR-irradiated RST. It also increased type I collagen expression in the dermal region and in fibroblasts in vitro. These results suggest that a hydrolytic system using the enzyme derived from Bacillus sp. can be used for the commercial production of LMAPs from food byproducts and that these LMAPs can be effective ingredients for improving photoaging-induced skin diseases.

Investigating the efficacy of topical application of Ipomoea carnea herbal cream in preventing skin damage induced by UVB radiation in a rat model

Ultraviolet-B irradiation is a common environmental stressor that has detrimental effects on human skin. Natural sunscreens are well-known for their ability to benefit inflamed sunburn and dry skin. This study examined the effect of formulated Ipomoea carnea herbal cream on UVB-induced skin damage. We screened the bioactive compounds of I. carnea crude extract, showing significant antioxidant activity. Additionally, we evaluated the cytotoxicity, revealing that I. carnea extract has less toxicity to vero cells (IC50 98.45 μg/mL) than to A375 cells (IC50 48.95 μg/mL). Based on this, we formulated the I. carnea herbal cream (FIHC) at 50, 100 and 200 mg concentrations and evaluated its organoleptic characteristics. Then, the rats were exposed to UVB radiation (32,800 J/m2) four times/week (on alternate days) before the cream was applied topically to the dorsal skin surface. Under UVB stress without treatment, rats showed deep dermal damage. In contrast, rats treated with the FIHC exhibited significantly reduced sunburn. Moreover, the histopathological and biochemical assays were confirmed by the topical application of FIHC, which had potentially reduced the skin elasticity and maintained the imbalanced enzyme and non-enzymatic antioxidant activity. Our findings amply demonstrate that the FIHC significantly accelerated the recovery of UVB-induced lesions through antioxidant and down-regulation of skin photodamage.

Protective Effect of Castanopsis sieboldii Extract against UVB-Induced Photodamage in Keratinocytes

Ultraviolet B (UVB) rays disrupt the skin by causing photodamage via processes such as reactive oxygen species (ROS) production, endoplasmic reticulum (ER) stress, DNA damage, and/or collagen degradation. Castanopsis sieboldii is an evergreen tree native to the southern Korean peninsula. Although it is known to have antioxidant and anti-inflammatory effects, its protective effect against photodamage in keratinocytes has not been investigated. Thus, in the present study, we investigated the effect of 70% ethanol extract of C. sieboldii leaf (CSL3) on UVB-mediated skin injuries and elucidated the underlying molecular mechanisms. CSL3 treatment restored the cell viability decreased by UVB irradiation. Moreover, CSL3 significantly inhibited UVB- or tert-butyl hydroperoxide-mediated ROS generation in HaCaT cells. ER stress was inhibited, whereas autophagy was upregulated by CSL3 treatment against UVB irradiation. Additionally, CSL3 increased collagen accumulation and cell migration, which were decreased by UVB exposure. Notably, epigallocatechin gallate, the major component of CSL3, improved the cell viability decreased by UVB irradiation through regulation of ER stress and autophagy. Conclusively, CSL3 may represent a promising therapeutic candidate for the treatment of UVB-induced skin damage.

Amino Acid Substitutions at P1 Position Change the Inhibitory Activity and Specificity of Protease Inhibitors BmSPI38 and BmSPI39 from Bombyx mori

It was found that silkworm serine protease inhibitors BmSPI38 and BmSPI39 were very different from typical TIL-type protease inhibitors in sequence, structure, and activity. BmSPI38 and BmSPI39 with unique structure and activity may be good models for studying the relationship between the structure and function of small-molecule TIL-type protease inhibitors. In this study, site-directed saturation mutagenesis at the P1 position was conducted to investigate the effect of P1 sites on the inhibitory activity and specificity of BmSPI38 and BmSPI39. In-gel activity staining and protease inhibition experiments confirmed that BmSPI38 and BmSPI39 could strongly inhibit elastase activity. Almost all mutant proteins of BmSPI38 and BmSPI39 retained the inhibitory activities against subtilisin and elastase, but the replacement of P1 residues greatly affected their intrinsic inhibitory activities. Overall, the substitution of Gly54 in BmSPI38 and Ala56 in BmSPI39 with Gln, Ser, or Thr was able to significantly enhance their inhibitory activities against subtilisin and elastase. However, replacing P1 residues in BmSPI38 and BmSPI39 with Ile, Trp, Pro, or Val could seriously weaken their inhibitory activity against subtilisin and elastase. The replacement of P1 residues with Arg or Lys not only reduced the intrinsic activities of BmSPI38 and BmSPI39, but also resulted in the acquisition of stronger trypsin inhibitory activities and weaker chymotrypsin inhibitory activities. The activity staining results showed that BmSPI38(G54K), BmSPI39(A56R), and BmSPI39(A56K) had extremely high acid-base and thermal stability. In conclusion, this study not only confirmed that BmSPI38 and BmSPI39 had strong elastase inhibitory activity, but also confirmed that P1 residue replacement could change their activity and inhibitory specificity. This not only provides a new perspective and idea for the exploitation and utilization of BmSPI38 and BmSPI39 in biomedicine and pest control, but also provides a basis or reference for the activity and specificity modification of TIL-type protease inhibitors.

Effect of A. polygama APEE (Actinidia polygama ethanol extract) or APWE (Actinidia polygama water extract) on wrinkle formation in UVB-irradiated hairless mice

BACKGROUND

Actinidia polygama (silver vine) is considered a medical plant which has been used in oriental medicine. It has been used for the treatment of pain, gout, rheumatoid arthritis, and inflammation. Few studies reported on the effect of Actinidia polygama (silver vine) on skin photoaging.

OBJECTIVE

To evaluate the anti-photoaging effect of the ethanol and water extracts of A. polygama (APEE and APWE, respectively) in UVB-irradiated hairless mice.

METHODS

SKH-1 hairless mice were exposed to UVB irradiation (30-60 mJ/cm² ), following orally APEE or APWE oral administration for 10 weeks. We examined the effect on winkle improvement by a measuring Fullscope, PRIMOS, Craniometer, and Cutometer. Furthermore, we analyzed histological changes in mouse dorsal skin through hematoxylin and eosin (H&E) and Masson's trichrome (MT) staining. The expression of matrix metalloproteinase (1, 3, and 9) was analyzed by immunoblotting.

RESULTS

Oral administration of APEE or APWE at 100 or 200 mg/kg in UVB-irradiated mice alleviated the symptoms of skin aging, such as wrinkling, epidermal hyperplasia, and water loss. In addition, the APEE or APWE oral administration increased skin elasticity by enhancing the production of type I collagen, elastin, and hyaluronic acid synthase and downregulating matrix metalloproteinase (1, 3, and 9) expression.

CONCLUSION

Based on results for our study, APEE or APWE could protect the UVB-mediated skin wrinkle and is new target for the developing anti-wrinkle cosmetics.

Brewers' spent hop revalorization for the production of high added-value cosmetics ingredients with elastase inhibition capacity

This article summarizes the analysis of α and β-acids and prenylflavonoids from brewers' spent hop (BSH) as source of bioactive molecules to improve skin integrity by inhibiting elastase activity. To maximize the efficacy of the BSH extracts, it was necessary to identify the most bioactive hop compounds and the extraction parameters to maximize elastase inhibition and total antioxidant capacity. Thus, a computational methodology was carried out to test the anti-elastase potential of these hop molecules, detecting cis-iso-α-cohumulone and 8-prenylnaringenin as main inhibitors. Then, BSH extracts were optimized to ensure the maximum extraction of bioactive compounds, using compatible solvents (water and 100% plant-based propanediol) according to the green cosmetic standards. Finally, a determination and quantification method based on HPLC-MS/MS was used to guarantee the presence of the bioactive molecules, detecting a higher concentration of cis-iso-α-cohumulone and 8-prenylnaringenin in those samples with high anti-elastase activity. By optimizing extraction conditions and agents, a BSH extract was designed, showing high antioxidant (81.9 mmol Trolox/L) and high anti-elastase capacities.

UVB-Induced Microvesicle Particle Release and Its Effects on the Cutaneous Microenvironment

Ultraviolet B radiation (UVB) has profound effects on human skin that results in a broad spectrum of immunological local and systemic responses and is the major cause of skin carcinogenesis. One important area of study in photobiology is how UVB is translated into effector signals. As the skin is exposed to UVB light, subcellular microvesicle particles (MVP), a subtype of bioactive extracellular vesicles, are released causing a variety of local and systemic immunological effects. In this review, we highlight keratinocyte MVP release in keratinocytes in response to UVB. Specifically, Platelet-activating factor receptor agonists generated by UVB result in MVP released from keratinocytes. The downstream effects of MVP release include the ability of these subcellular particles to transport agents including the glycerophosphocholine-derived lipid mediator Platelet-activating factor (PAF). Moreover, even though UVB is only absorbed in the epidermis, it appears that PAF release from MVPs also mediates systemic immunosuppression and enhances tumor growth and metastasis. Tumor cells expressing PAF receptors can use this mechanism to evade chemotherapy responses, leading to treatment resistance for advanced cancers such as melanoma. Furthermore, novel pharmacological agents provide greater insight into the UVB-induced immune response pathway and a potential target for pharmacological intervention. This review outlines the need to more clearly elucidate the mechanism linking UVB-irradiation with the cutaneous immune response and its pathological manifestations. An improved understanding of this process can result in new insights and treatment strategies for UVB-related disorders from carcinogenesis to photosensitivity.

Vascular Endothelial Growth Factor as an Immediate-Early Activator of Ultraviolet-Induced Skin Injury

The negative health consequences of acute ultraviolet (UV) exposure are evident, with reports of 30,000 emergency room visits annually to treat the effects of sunburn in the United States alone. The acute effects of sunburn include erythema, edema, severe pain, and chronic overexposure to UV radiation, leading to skin cancer. Whereas the pain associated with the acute effects of sunburn may be relieved by current interventions, existing post-sunburn treatments are not capable of reversing the cumulative and long-term pathological effects of UV exposure, an unmet clinical need. Here we show that activation of the vascular endothelial growth factor (VEGF) pathway is a direct and immediate consequence of acute UV exposure, and activation of VEGF signaling is necessary for initiating the acute pathological effects of sunburn. In UV-exposed human subjects, VEGF signaling is activated within hours. Topical delivery of VEGF pathway inhibitors, targeted against the ligand VEGF-A (gold nanoparticles conjugated with anti-VEGF antibodies) and small-molecule antagonists of VEGF receptor signaling, prevent the development of erythema and edema in UV-exposed mice. These findings collectively suggest targeting VEGF signaling may reduce the subsequent inflammation and pathology associated with UV-induced skin damage, revealing a new postexposure therapeutic window to potentially inhibit the known detrimental effects of UV on human skin. It is essential to emphasize that these preclinical studies must not be construed as suggesting in any way the use of VEGF inhibitors as a sunburn treatment in humans because warranted future clinical studies and appropriate agency approval are essential in that regard.

Protective Effect of Polymethoxyflavones Isolated from Kaempferia parviflora against TNF-α-Induced Human Dermal Fibroblast Damage

Similar to other organs, the skin undergoes a natural aging process. Moreover, constant direct exposure to environmental stresses, including ultraviolet irradiation, causes the signs of skin aging to appear rather early. Reactive oxygen species (ROS) and inflammatory responses accelerate skin damage in extrinsic aging. In this study, we aimed to investigate the skin protective effects of polymethoxyflavones found in Kaempferia parviflora against oxidative stress and inflammation-induced damage in human dermal fibroblasts (HDFs) stimulated by tumor necrosis factor-α (TNF-α). The experimental data identified 5,7,4' trimethoxyflavone (TMF) as the most potent constituent in preventing TNF-α-induced HDF damage among the tested compounds and it was not only effective in inhibiting matrix metalloproteinase-1 (MMP-1) production but also in stimulating collagen, type I, and alpha 1 (COLIA1) expression. TMF suppressed TNF-α-stimulated generation of ROS and pro-inflammatory mediators, such as cyclooxygenase-2 (COX-2), interleukin (IL)-1β, and IL-6 in HDFs. TMF also inhibited the pathways regulating fibroblast damage, including mitogen-activated protein kinase (MAPK), activator protein 1 (AP-1), and nuclear factor-kappa B (NF-κB). In conclusion, TMF may be a potential agent for preventing skin aging and other dermatological disorders associated with oxidative stress and inflammation.

Ergothioneine alleviates senescence of fibroblasts induced by UVB damage of keratinocytes via activation of the Nrf2/HO-1 pathway and HSP70 in keratinocytes

Ultraviolet B (UVB) irradiation induces skin damage and photoaging through several deleterious effects, including generation of reactive oxygen species (ROS), apoptosis of epidermal cells, inflammation, and collagen degradation in fibroblasts. Ergothioneine (EGT) is a naturally occurring amino acid with potential biological properties. We evaluated whether EGT protects against UVB-induced photoaging using a keratinocyte/fibroblast co-culture system. Keratinocytes were pretreated with EGT, irradiated with UVB, and co-cultured with fibroblasts. In keratinocytes, ROS production and apoptosis were assessed. We also analyzed the Nrf2/HO-1 pathway, HSP70, proapoptotic proteins, and paracrine cytokines by Western blotting and real-time PCR. Collagen degradation-related genes and senescence were also assessed in fibroblasts. EGT pretreatment of keratinocytes significantly inhibited downregulation of the Nrf2/HO-1 pathway and HSP70, and protected keratinocytes by suppressing production of ROS and cleavage of proapoptotic proteins, including caspase-8 and PARP. Furthermore, EGT significantly reduced the paracrine cytokines, including IL-1β, IL-6, and TNF-α. In co-cultures of fibroblasts with EGT-treated keratinocytes, the expression levels of collagen degradation-related genes and fibroblast senescence were significantly decreased; however, synthesis of procollagen type I was significantly increased. Our results confirm that EGT suppresses the modification of collagen homeostasis in fibroblasts by preventing downregulation of the Nrf2/HO-1 pathway and HSP70 in keratinocytes following UVB irradiation.

Cellular Function of Annexin A1 Protein Mimetic Peptide Ac2-26 in Human Skin Keratinocytes HaCaT and Fibroblast Detroit 551 Cells

Inflammation of the skin is the most common dermatological problem in human. The anti-inflammatory mediated responses of the skin cells provide a mechanism for combating these conditions. Annexin A1 (AnxA1) is one of the proteins that has been shown to have a potent anti-inflammatory effect. However, the effects and mechanisms of AnxA1 in skin keratinocyte and fibroblast have not been reported yet. In the current study, we hypothesized that Ac2-26, AnxA1 mimetic peptide, ameliorates inflammation and wrinkle formation in human skin cells. Therefore, we aimed to identify whether Ac2-26 has anti-inflammatory and anti-wrinkle effects in human keratinocyte (HaCaT) and fibroblast (Detroit 551) cells, respectively. Human HaCaT cells were stimulated by TNF-α/IFN-γ with or without Ac2-26, to identify the anti-inflammatory effect. Human Detroit 551 cells were treated with Ac2-26 to verify the anti-wrinkle effect. Initially, cell cytotoxicity was carried out in each cell line treated using Ac2-26 by MTT assay. Human MDA, IL-8, and procollagen secretion were detected by ELISA assay. The inflammatory chemokines were measured by qRT-PCR analysis. To demonstrate the mechanism, MAPK, NF-κB, JAK/STAT, and MMPs were analyzed by Western blotting. As a result, we identified that Ac2-26 significantly decreased the expression of TNF-α/IFN-γ-stimulated pro-inflammatory chemokines, including IL-1β, IL-6, IL-8, MDC, TARC, and TNF-α, by inhibiting the activation of MAPK, NF-κB, and JAK/STAT pathway in TNF-α/IFN-γ-stimulated HaCaT human keratinocytes. In addition, we also identified that Ac2-26 significantly induced collagen synthesis by generating pro-collagen, and suppressed collagen degradation by inhibiting the collagenase MMP-1 and MMP-8 expression. Collectively, these results suggest that Ac2-26 shows anti-inflammatory and anti-wrinkling effect. These effects may lead to the development of preventive and therapeutic application for inflammation-related skin disease and wrinkle formation.

Antiwrinkle and Antimelanogenesis Effects of Tyndallized Lactobacillus acidophilus KCCM12625P

UVB irradiation can induce generation of reactive oxygen species (ROS) that cause skin aging or pigmentation. Lactobacillus acidophilus is a well-known probiotic strain that regulates skin health through antimicrobial peptides and organic products produced by metabolism and through immune responses. In this study, we investigated the antioxidative, antiwrinkle, and antimelanogenesis effects of tyndallized Lactobacillus acidophilus KCCM12625P (AL). To analyze the effects of AL on UV irradiation-induced skin wrinkle formation in vitro, human keratinocytes and human dermal fibroblasts were exposed to UVB. Subsequent treatment with AL induced antiwrinkle effects by regulating wrinkle-related genes such as matrix metalloproteinases (MMPs), SIRT-1, and type 1 procollagen (COL1AL). In addition, Western blotting assays confirmed that regulation of MMPs by AL in keratinocytes was due to regulation of the AP-1 signaling pathway. Furthermore, we confirmed the ability of AL to regulate melanogenesis in B16F10 murine melanoma cells treated with α-melanocyte-stimulating hormone (α-MSH). In particular, AL reduced the mRNA expression of melanogenesis-related genes such as tyrosinase, TYRP-1, and TYRP-2. Finally, we used Western blotting assays to confirm that the antimelanogenesis role of AL was due to its regulation of the cyclic adenosine monophosphate (cAMP) signaling pathway. Collectively, these results indicate that AL has an antiwrinkle activity in damaged skin and can inhibit melanogenesis. Thus, AL should be considered an important substance for potential use in anti-aging drugs or cosmetics.

Anti‑photoaging effect of fermented agricultural by‑products on ultraviolet B‑irradiated hairless mouse skin

Processed products from agricultural produce generate a large number of agricultural by‑products that contain a number of functional substances. These are often discarded owing to the lack of suitable processing methods. The present study investigated the anti‑photoaging properties of fermented rice bran (FRB), soybean cake (FSB) and sesame seed cake (FSC) on ultraviolet B (UVB)‑irradiated hairless mouse skin. Results indicated that the oral administration of FRB, FSB and FSC effectively inhibited the UVB irradiation‑induced expression of matrix metalloproteinase (MMP)‑2, MMP‑9, MMP‑3 and MMP‑13. Reverse transcription‑quantitative polymerase chain reaction results also demonstrated that FRB, FSB and FSC significantly inhibited the UVB‑induced expression of the genes encoding tumor necrosis factor‑α, inducible nitric oxide synthase, interleukin (IL)‑6 and IL‑1β when compared with the UVB‑vehicle group (P<0.05). Additionally, collagen degradation and mast cell infiltration were reduced in hairless mouse skin. Furthermore, UVB‑induced wrinkle formation was also significantly reduced in mouse skin compared with the UVB‑vehicle group (P<0.05). These results reveal that fermented agricultural by‑products may serve as potential functional materials with anti‑photoaging activities.

Anti-aging and Sunscreens: Paradigm Shift in Cosmetics

Skin, being one of the vital organs and a protective barrier needs to be pampered and taken care of from early childhood. It is the most visible and the widest exposed organ and by far reflects the general health condition and the aging process in humans. Both intrinsic and extrinsic factors contribute to this complex biological process of skin aging. In recent times, skin health and its beauty is perceived as an indicator of one’s health which has resulted in an increasing demand for anti-aging products. Exposure to UV radiation is considered to be one of the factors responsible for aging termed as photoaging. In this review, we have discussed the various factors which may accelerate the process of skin aging. Various approaches and strategies to delay the process of skin aging have been emphasized upon. The patents filed in the area of anti-aging and sunscreen products have also been reviewed to gain an insight into the new formulations which have been developed as an anti-aging product. There has been a tremendous rise in the cosmetic and cosmeceuticals market with products having a dual activity of anti-aging and sun protection. Research is constantly on the rise to ensure the safety of these products. Alternatives to the current topical application of sunscreen are being considered to overcome the drawback of reapplication of the sunscreen often which can be a boon to the cosmeceutical market.

Inhibitory role of silk cocoon extract against elastase, hyaluronidase and UV radiation-induced matrix metalloproteinase expression in human dermal fibroblasts and keratinocytes

Topical delivery of potent antioxidants maintain the redox balance of the skin, which leads to the downregulation of matrix metalloproteinase (MMP) expression and prevents UV radiation-induced photoaging. In this study, we aimed at investigating the inhibitory role of silk cocoon extract (SCE) isolated from the Antheraea assamensis (AA), Bombyx mori (BM), and Philosamia ricini (PR) silk varieties against UV radiation-induced MMP expression. Incubation of elastase and hyaluronidase with Antheraea assamensis silk cocoon extract (AASCE) caused 50% inhibition of activity. The assessment of total collagen content using the Sirius red assay showed that AASCE (10 μg mL-1) and Philosamia ricini silk cocoon extract (PRSCE at 100 μg mL-1 concentration) post-treatment significantly enhanced the total collagen content in UVA1 and UVB irradiated HDF cells, whereas BM silk cocoon extract (BMSCE at 100 μg mL-1 concentration) post-treatment significantly enhanced the total collagen content in UVA1-irradiated HDF cells. Gene expression studies revealed AASCE and PRSCE post-treatment downregulated the expression of interleukin (IL)-6, MMP-1 and upregulated procollagen genes in UV irradiated HDF cells. Gelatin zymography studies with AASCE post-treatment downregulated the release of MMP-2 and MMP-9 by HaCaT cells. The overall results validate AASCE efficiently shielding UV radiation-induced collagen and elastin degradation by downregulation of MMP expression, substantiating its further use as a potent antioxidant complement in skin care formulations.

Induction of angiogenic and inflammation-associated dermal biomarkers following acute UVB exposure on bio-engineered pigmented dermo-epidermal skin substitutes in vivo

PURPOSE

Ultraviolet (UV) radiation adversely affects skin health at cellular and molecular levels. Hence, UV radiation can directly induce inflammatory responses in the dermis by inducing erythema, edema, inflammation, dermal fibroblasts alterations, and extracellular matrix modifications.

METHODS

Human keratinocytes, melanocytes, and fibroblasts were isolated from skin biopsies, cultured, and expanded in vitro. Fibroblasts were seeded into collagen type I hydrogels that were subsequently covered by keratinocytes and melanocytes. These pigmented dermo-epidermal skin substitutes (pigmDESS) were transplanted for 5 weeks onto full-thickness skin wounds on the back of immuno-incompetent rats, exposed to a single UVB dose of 250 mJ/cm² or unexposed and excised after 1 week. The effects onto the dermis were assessed regarding cell number, cell phenotype, and cell proliferation. Local inflammation by granulocytes (HIS48) or macrophages (CD11b, iNOS) was analyzed by immunohistochemistry staining.

RESULTS

We observed a significantly enhanced ingrowth rate of blood capillaries, but not of lymphatic capillaries at 1 week post-irradiation. Moreover, the enhanced vascularization of pigmDESS after UVB exposure was concomitant with a high infiltration of granulocytes and monocytes/macrophages to the dermal part of grafts. In addition, a heterogeneous expression of HIF-1α and TNFα was detected at this early phase after UVB exposure. In local cellular response examination, results only show a moderate cell proliferation in the dermis.

CONCLUSIONS

We were able to define early markers of UVB-induced effects in the dermis of pigmDESS. Overall, a single UVB dose induces temporary acute angiogenic and immune responses during the early post-irradiation phase in vivo.

Protective Effect of Sulfated Polysaccharides from Celluclast-Assisted Extract of Hizikia fusiforme Against Ultraviolet B-Induced Skin Damage by Regulating NF-κB, AP-1, and MAPKs Signaling Pathways In Vitro in Human Dermal Fibroblasts

Our previous study evaluated the antioxidant activities of sulfated polysaccharides from Celluclast-assisted extract of Hizikia fusiforme (HFPS) in vitro in Vero cells and in vivo in zebrafish. The results showed that HFPS possesses strong antioxidant activity and suggested the potential photo-protective activities of HFPS. Hence, in the present study, we investigated the protective effects of HFPS against ultraviolet (UV) B-induced skin damage in vitro in human dermal fibroblasts (HDF cells). The results indicate that HFPS significantly reduced intracellular reactive oxygen species (ROS) level and improved the viability of UVB-irradiated HDF cells in a dose-dependent manner. Furthermore, HFPS significantly inhibited intracellular collagenase and elastase activities, remarkably protected collagen synthesis, and reduced matrix metalloproteinases (MMPs) expression by regulating nuclear factor kappa B (NF-κB), activator protein 1 (AP-1), and mitogen-activated protein kinases (MAPKs) signaling pathways in UVB-irradiated HDF cells. These results suggest that HFPS possesses strong UV protective effect, and can be a potential ingredient in the pharmaceutical and cosmetic industries.

The Anti-Wrinkle Mechanism of Melatonin in UVB Treated HaCaT Keratinocytes and Hairless Mice via Inhibition of ROS and Sonic Hedgehog Mediated Inflammatory Proteins

Though melatonin is known to improve ultraviolet B (UVB)-induced oxidative damage and inflammatory conditions via the blockade of the nuclear factor (NF)-κB, interleukin (IL)-6, there is no report on the anti-wrinkle effect of melatonin to date. Hence in the present study, the anti-wrinkle mechanism of melatonin was elucidated in UVB treated HaCaT keratinocytes and hairless mice. Herein melatonin protected against a radical initiator tert-Butyl hydroperoxide (t-BOOH) induced reactive oxygen species (ROS) production, matrix metalloprotease 1 (MMP-1), pro-collagen and cytotoxicity in HaCaT keratinocytes. Additionally, melatonin suppressed the expression of sonic hedgehog (SHH) and GLI1 for hedgehog signaling and p-NF-κB, cyclooxygenase (COX-2), phospho-extracellular signal-regulated kinase-1 (p-ERK) for inflammatory responses in UVB treated HaCaT keratinocytes. Furthermore, melatonin protected skin from wrinkle formation, transdermal water loss in hairless mice irradiated by UVB for 8 weeks. Notably, melatonin prevented against epidermal thickness and dermal collagen degradation in UVB irradiated hairless mice by Hematoxylin and Eosin and Masson’s trichrome staining. Taken together, these findings suggest that melatonin reduces wrinkle formation via inhibition of ROS/SHH and inflammatory proteins such as NF-κB/COX-2/ERK/MMP1.

Anti-Inflammatory Effect of ETAS®50 by Inhibiting Nuclear Factor-κB p65 Nuclear Import in Ultraviolet-B-Irradiated Normal Human Dermal Fibroblasts

Ultraviolet (UV) irradiation induces proinflammatory responses in skin cells, including dermal fibroblasts, accelerating premature skin aging (photoaging). ETAS 50, a standardized extract from the Asparagus officinalis stem, is a novel and unique functional food that suppresses proinflammatory responses of hydrogen peroxide-stimulated skin fibroblasts and interleukin- (IL-) 1β-stimulated hepatocytes. To elucidate its antiphotoaging potencies, we examined whether ETAS 50 treatment after UV-B irradiation attenuates proinflammatory responses of normal human dermal fibroblasts (NHDFs). UV-B-irradiated NHDFs showed reduced levels of the cytosolic inhibitor of nuclear factor-κB α (IκBα) protein and increased levels of nuclear p65 protein. The nuclear factor-κB nuclear translocation inhibitor JSH-23 abolished UV-B irradiation-induced IL-1β mRNA expression, indicating that p65 regulates transcriptional induction. ETAS 50 also markedly suppressed UV-B irradiation-induced increases in IL-1β mRNA levels. Immunofluorescence analysis revealed that ETAS 50 retained p65 in the cytosol after UV-B irradiation. Western blotting also showed that ETAS 50 suppressed the UV-B irradiation-induced increases in nuclear p65 protein. Moreover, ETAS 50 clearly suppressed UV-B irradiation-induced distribution of importin-α protein levels in the nucleus without recovering cytosolic IκBα protein levels. These results suggest that ETAS 50 exerts anti-inflammatory effects on UV-B-irradiated NHDFs by suppressing the nuclear import machinery of p65. Therefore, ETAS 50 may prevent photoaging by suppressing UV irradiation-induced proinflammatory responses of dermal fibroblasts.

Evaluation of the UVB-screening capacity and restorative effects exerted by farnesol gel on UVB-caused sunburn

Farnesol, a natural 15-carbon organic compound, has various microbiological and cellular activities. It has been found to exert apoptosis-inducing effects against carcinoma cells as well as antiallergic and anti-inflammatory effects in vivo. In the current study, a series of formulations composed of various concentrations of hydroxypropyl methylcellulose (HPMC) with the addition of hyaluronan (HA) and xanthan gum (XG) was designed to evaluate the UVB-screening and H₂ O₂ -eliminating effects of farnesol in normal fibroblasts. Farnesol at 0.005, 0.0075, and 0.01% exhibited significant capacity for H₂ O₂ scavenging; at 0.0025%, it showed insignificant effects. Under 120-min UVB exposure, screening with plural gel composed of 0.0025% farnesol, 0.5% HA, and 0.5% XG containing 1.5% or 2% HPMC retained normal fibroblast viability. After 60-min exposure to UVB, screening with plural gel composed of farnesol, HA, XG, and 0.5%, 1.0%, 1.5%, or 2% HPMC decreased the ratio of the G1 phase and increased ratio of the S phase in comparison with the accumulated cell cycle of the normal fibroblasts without screening. The gel with 2% HPMC displayed the strongest cell cycle-reversal ability. In vivo histopathological results showed that the prepared plural gels with 0.5% or 2% HPMC and farnesol, HA, and XG had greater antiphotoaging and reparative effects against UVB-induced changes and damage in the skin. In conclusion, the current in vitro and in vivo results demonstrated that the prepared plural composed of 0.0025% farnesol, 0.5% HA, 0.5% XG, and 2% HPMC possessed the greatest UVB-screening capacity and the strongest restorative effects on UVB-induced sunburned skin.

Triolein reduces MMP-1 upregulation in dermal fibroblasts generated by ROS production in UVB-irradiated keratinocytes

BACKGROUND

Cytokine production and oxidative stress generated by ultraviolet radiation B (UVB) skin exposure are main factors of skin photoaging. Interleukin-6 (IL-6) produced by irradiated keratinocytes is proposed to have a role in metalloproteinases (MMPs) expression activation in dermal fibroblasts.

OBJECTIVES

We examined the effect of triolein treatment of UVB-irradiated keratinocytes on MMP1 (interstitial collagenase) expression response of dermal fibroblasts. We assayed UVB-irradiated keratinocytes soluble signals, mainly IL-6 and reactive oxygen species (ROS).

METHODS

IL-6 expression and ROS generation were assayed in UVB-irradiated keratinocytes. MMP1 mRNA expression response was assayed in fibroblasts grown in keratinocytes conditioned medium. We evaluated the effect of treating keratinocytes with triolein on IL-6 expression and ROS generation in keratinocytes, and MMP1 expression in fibroblasts.

RESULTS

The irradiation of epidermal cells with sublethal UVB doses increased IL-6 expression and ROS generation. Conditioned culture medium collected from keratinocytes was used to culture dermal fibroblasts. MMP1 mRNA expression increase was observed in fibroblasts cultured in medium collected from UVB-irradiated keratinocytes. Triolein treatment reduced the IL-6 expression and ROS generation in keratinocytes and this effect was reflected in downregulation of MMP1 expression in fibroblasts.

CONCLUSIONS

Triolein reduces both the expression of IL-6 and ROS generation in irradiated keratinocytes. It seems to exert an anti-inflammatory and anti-oxidative stress effect on irradiated keratinocytes that in turn reduces MMP1 expression in dermal fibroblasts. Collectively, these results indicate that triolein could act as a photoprotective agent.

Reduction of facial wrinkles by hydrolyzed water-soluble egg membrane associated with reduction of free radical stress and support of matrix production by dermal fibroblasts

Objective

The aim of this study was to evaluate the effects of water-soluble egg membrane (WSEM) on wrinkle reduction in a clinical pilot study and to elucidate specific mechanisms of action using primary human immune and dermal cell-based bioassays.

Methods

To evaluate the effects of topical application of WSEM (8%) on human skin, an open-label 8-week study was performed involving 20 healthy females between the age of 45 years and 65 years. High-resolution photography and digital analysis were used to evaluate the wrinkle depth in the facial skin areas beside the eye (crow’s feet). WSEM was tested for total antioxidant capacity and effects on the formation of reactive oxygen species by human polymorphonuclear cells. Human keratinocytes (HaCaT cells) were used for quantitative polymerase chain reaction analysis of the antioxidant response element genes Nqo1, Gclm, Gclc, and Hmox1. Evaluation of effects on human primary dermal fibroblasts in vitro included cellular viability and production of the matrix components collagen and elastin.

Results

Topical use of a WSEM-containing facial cream for 8 weeks resulted in a significant reduction of wrinkle depth (P<0.05). WSEM contained antioxidants and reduced the formation of reactive oxygen species by inflammatory cells in vitro. Despite lack of a quantifiable effect on Nrf2, WSEM induced the gene expression of downstream Nqo1, Gclm, Gclc, and Hmox1 in human keratinocytes. Human dermal fibroblasts treated with WSEM produced more collagen and elastin than untreated cells or cells treated with dbcAMP control. The increase in collagen production was statistically significant (P<0.05).

Conclusion

The topical use of WSEM on facial skin significantly reduced the wrinkle depth. The underlying mechanisms of this effect may be related to protection from free radical damage at the cellular level and induction of several antioxidant response elements, combined with stimulation of human dermal fibroblasts to secrete high levels of matrix components.

Epithelial-mesenchymal interaction mechanisms leading to the over-expression of neprilysin are involved in the UVB-induced formation of wrinkles in the skin

In clinical studies, the formation of facial wrinkles has been closely linked to the loss of elastic properties of the skin. Repetitive UVB irradiation of animal skin at suberythemal doses significantly reduces its elastic properties, resulting in the formation of wrinkles. That also elicits a marked alteration in the three-dimensional structure of elastic fibres, which is closely associated with a subsequent reduction in the elastic properties of the skin. While UVB irradiation stimulates the activity of skin fibroblast-derived elastase in the dermis, a synthetic inhibitor specific for skin fibroblast-derived elastase as well as an extract of Zingiber officinale (L.) Rose capable of inhibiting skin fibroblast-derived elastase, but not neutrophil elastase, prevented wrinkle formation in our studies of animal and human facial skin, respectively. The close interrelationship among wrinkle formation, elastic properties and elastic fibre linearity is revealed by the effects of different concentrations of the elastase inhibitor, which indicates that enhanced elastase activity by dermal fibroblasts plays a pivotal role in the UVB wrinkling mechanism. Fortunately, we were able to identify human skin fibroblast-derived elastase as the previously known enzyme neprilysin/neutral endopeptidase. Using both a UVB-conditioned medium assay and a co-culture system, we characterized the epithelial-mesenchymal interaction between keratinocytes and fibroblasts which leads to increased expression of neprilysin at the transcriptional, translational and enzymatic levels. Our results demonstrate that interleukin-1α and granulocyte-macrophage colony-stimulating factor are intrinsic cytokines secreted by UVB-exposed keratinocytes that stimulate the expression of neprilysin by skin fibroblasts.

Recovery of extracellular matrix components by enalapril maleate during the repair process of ultraviolet B-induced wrinkles in mouse skin

The renin–angiotensin system is known to be involved in skin remodeling and inflammation. Previously, we reported that ultraviolet B (UVB) irradiation enhanced angiotensin-converting enzyme (ACE) expression and angiotensin II levels in hairless mouse skin, and an ACE inhibitor, enalapril maleate (EM), accelerated repair of UVB-induced wrinkles. In this study, we analyzed gene expression profiles by DNA microarray and protein distribution patterns using an immunofluorescence method to clarify the process of EM-accelerated wrinkle repair in UVB-irradiated hairless mouse skin. In the microarray analysis, we detected EM-induced up-regulation of various extracellular matrix (ECM)-related genes in the UVB-irradiated skin. In the immunofluorescence, we confirmed that type I collagen α1 chain, fibrillin 1, elastin and dystroglycan 1 in the skin decreased after repeated UVB irradiation but staining for these proteins was improved by EM treatment. In addition, ADAMTS2 and MMP-14 also increased in the EM-treated skin. Although the relationship between these molecules and wrinkle formation is not clear yet, our present data suggest that the molecules are involved in the repair of UVB-induced wrinkles.

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Effects of an ACE inhibitor enalapril maleate (EM) on skin were examined.

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Extracellular matrix (ECM) expression decreased in UVB-irradiated mouse skin.

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EM up-regulated ECM gene expression in the UVB-irradiated skin.

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EM accelerated recovery of ECM protein localization in the UVB-irradiated skin.

Nanodiamonds protect skin from ultraviolet B-induced damage in mice

BACKGROUND

Solar ultraviolet (UV) radiation causes various deleterious effects, and UV blockage is recommended for avoiding sunburn. Nanosized titanium dioxide and zinc oxide offer effective protection and enhance cosmetic appearance but entail health concerns regarding their photocatalytic activity, which generates reactive oxygen species. These concerns are absent in nanodiamonds (NDs). Among the UV wavelengths in sunlight, UVB irradiation primarily threatens human health.

RESULTS

The efficacy and safety of NDs in UVB protection were evaluated using cell cultures and mouse models. We determined that 2 mg/cm(2) of NDs efficiently reduced over 95% of UVB radiation. Direct UVB exposure caused cell death of cultured keratinocyte, fibroblasts and skin damage in mice. By contrast, ND-shielding significantly protected the aforementioned pathogenic alterations in both cell cultures and mouse models.

CONCLUSIONS

NDs are feasible and safe materials for preventing UVB-induced skin damage.

Cell Autonomous and Non-Autonomous Effects of Senescent Cells in the Skin

Human and mouse skin accumulate senescent cells in both the epidermis and dermis during aging. When chronically present, senescent cells are thought to enhance the age-dependent deterioration of the skin during extrinsic and intrinsic aging. However, when transiently present, senescent cells promote optimal wound healing. Here, we review recent studies on how senescent cells and the senescence-associated secretory phenotype (SASP) contribute to different physiological and pathophysiological conditions in the skin with a focus on some of the cell autonomous and non-autonomous functions of senescent cells in the context of skin aging and wound healing.

Biological mechanisms underlying the ultraviolet radiation-induced formation of skin wrinkling and sagging II: over-expression of neprilysin plays an essential role

Our previous studies strongly indicated that the up-regulated activity of skin fibroblast-derived elastase plays a pivotal role in wrinkling and/or sagging of the skin via the impairment of elastic fiber configuration and the subsequent loss of skin elasticity. Fortunately, we succeeded in identifying human skin fibroblast-derived elastase as a previously known enzyme, neprilysin or neutral endopeptidase (NEP). We have also characterized epithelial-mesenchymal paracrine cytokine interactions between UVB-exposed-keratinocytes and dermal fibroblasts and found that interleukin-1α and granulocyte macrophage colony stimulatory factor (GM-CSF) are intrinsic cytokines secreted by UVB-exposed keratinocytes that stimulate the expression of neprilysin by fibroblasts. On the other hand, direct UVA exposure of human fibroblasts significantly stimulates the secretion of IL-6 and also elicits a significant increase in the gene expression of matrix metallo-protease(MMP)-1 as well as neprilysin (to a lesser extent), which is followed by distinct increases in their protein and enzymatic activity levels. Direct UVA exposure of human keratinocytes also stimulates the secretion of IL-6, IL-8 and GM-CSF but not of IL-1 and endothelin-1. These findings suggest that GM-CSF secreted by UVA-exposed keratinocytes as well as IL-6 secreted by UVA-exposed dermal fibroblasts play important and additional roles in UVA-induced sagging and wrinkling by up-regulation of neprilysin and MMP-1, respectively, in dermal fibroblasts.

Biological mechanisms underlying the ultraviolet radiation-induced formation of skin wrinkling and sagging I: reduced skin elasticity, highly associated with enhanced dermal elastase activity, triggers wrinkling and sagging

The repetitive exposure of skin to ultraviolet B (UVB) preferentially elicits wrinkling while ultraviolet A (UVA) predominantly elicits sagging. In chronically UVB or UVA-exposed rat skin there is a similar tortuous deformation of elastic fibers together with decreased skin elasticity, whose magnitudes are greater in UVB-exposed skin than in UVA-exposed skin. Comparison of skin elasticity with the activity of matrix metalloproteinases (MMPs) in the dermis of ovariectomized rats after UVB or UVA irradiation demonstrates that skin elasticity is more significantly decreased in ovariectomized rats than in sham-operated rats, which is accompanied by a reciprocal increase in elastase activity but not in the activities of collagenases I or IV. Clinical studies using animal skin and human facial skin demonstrated that topical treatment with a specific inhibitor or an inhibitory extract of skin fibroblast-derived elastase distinctly attenuates UVB and sunlight-induced formation of wrinkling. Our results strongly indicated that the upregulated activity of skin fibroblast-derived elastase plays a pivotal role in wrinkling and/or sagging of the skin via the impairment of elastic fiber configuration and the subsequent loss of skin elasticity.

Polycomponent mesotherapy formulations for the treatment of skin aging and improvement of skin quality

Skin aging can largely be attributed to dermal fibroblast dysfunction and a decrease in their biosynthetic activity. Regardless of the underlying causes, aging fibroblasts begin to produce elements of the extracellular matrix in amounts that are insufficient to maintain the youthful appearance of skin. The goal of mesopreparations is primarily to slow down and correct changes in skin due to aging. The rationale for developing complex polycomponent mesopreparations is based on the principle that aging skin needs to be supplied with the various substrates that are key to the adequate functioning of the fibroblast. The quintessential example of a polycomponent formulation – NCTF^® (New Cellular Treatment Factor) – includes vitamins, minerals, amino acids, nucleotides, coenzymes and antioxidants, as well as hyaluronic acid, designed to help fibroblasts function more efficiently by providing a more optimal environment for biochemical processes and energy generation, as well as resisting the effects of oxidative stress. In vitro experiments suggest that there is a significant increase in the synthetic and prophylactic activity of fibroblasts with treated NCTF, and a significant increase in the ability of cells to resist oxidative stress. The current article looks at the rationale behind the development of polycomponent mesopreparations, using NCTF as an example.

Topically applied Hsp90 inhibitor 17AAG inhibits UVR-induced cutaneous squamous cell carcinomas

We present here that heat-shock protein 90 (Hsp90) inhibitor 17-(allylamino)-17-demethoxygeldanamycin (17AAG), when topically applied to mouse skin, inhibits UVR-induced development of cutaneous squamous cell carcinoma (SCC). In these experiments, DMSO:acetone (1:40 v/v) solution of 17AAG (500 nmol) was applied topically to mouse skin in conjunction with each UVR exposure (1.8 kJ m(-2)). The UVR source was Kodacel-filtered FS-40 sun lamps (approximately 60% UVB and 40% UVA). In independent experiments with three separate mouse lines (SKH-1 hairless mice, wild-type FVB, and protein kinase C epsilon (PKCɛ)-overexpressing transgenic FVB mice), 17AAG treatment increased the latency and decreased both the incidence and multiplicity of UVR-induced SCC. Topical 17AAG alone or in conjunction with UVR treatments elicited neither skin nor systemic toxicity. 17AAG-caused inhibition of SCC induction was accompanied by a decrease in UVR-induced (1) hyperplasia, (2) Hsp90β-PKCɛ interaction, and (3) expression levels of Hsp90β, Stat3, pStat3Ser727, pStat3Tyr705, pAktSer473, and matrix metalloproteinase (MMP). The results presented here indicate that topical Hsp90 inhibitor 17AAG is effective in prevention of UVR-induced epidermal hyperplasia and SCC. One may conclude from the preclinical data presented here that topical 17AAG may be useful for prevention of UVR-induced inflammation and cutaneous SCC either developed in UVR-exposed or organ transplant population.

Ultraviolet radiation, aging and the skin: prevention of damage by topical cAMP manipulation

Being the largest and most visible organ of the body and heavily influenced by environmental factors, skin is ideal to study the long-term effects of aging. Throughout our lifetime, we accumulate damage generated by UV radiation. UV causes inflammation, immune changes, physical changes, impaired wound healing and DNA damage that promotes cellular senescence and carcinogenesis. Melanoma is the deadliest form of skin cancer and among the malignancies of highest increasing incidence over the last several decades. Melanoma incidence is directly related to age, with highest rates in individuals over the age of 55 years, making it a clear age-related disease. In this review, we will focus on UV-induced carcinogenesis and photo aging along with natural protective mechanisms that reduce amount of “realized” solar radiation dose and UV-induced injury. We will focus on the theoretical use of forskolin, a plant-derived pharmacologically active compound to protect the skin against UV injury and prevent aging symptoms by up-regulating melanin production. We will discuss its use as a topically-applied root-derived formulation of the Plectranthus barbatus (Coleus forskolii) plant that grows naturally in Asia and that has long been used in various Aryuvedic teas and therapeutic preparations.

Suppression of UV-induced wrinkle formation by induction of HSP70 expression in mice

UV-induced wrinkle formation owing to the degeneration of the extracellular matrix (ECM) is a major dermatological problem in which abnormal activation of matrix metalloproteinases (MMPs) and elastases have important roles. Heat shock protein 70 (HSP70) has cytoprotective and anti-inflammatory activities. In this study, we examined the effect of HSP70 expression on UV-induced wrinkle formation. Mild heat treatment (exposure to heated water at 42 °C) of the dorsal skin of hairless mice induced the expression of HSP70. The long-term repeated exposure to UV induced epidermal hyperplasia, decreased skin elasticity, degeneration of ECM, and wrinkle formation, which could be suppressed in mice concomitantly subjected to this heat treatment. The UV-induced epidermal hyperplasia, decreased skin elasticity, and degeneration of ECM were less apparent in transgenic mice expressing HSP70 than in wild-type mice. UV-induced fibroblast cell death, infiltration of inflammatory cells, and activation of MMPs and elastase in the skin were also suppressed in the transgenic mice. This study provides evidence for an inhibitory effect of HSP70 on UV-induced wrinkle formation. The results suggest that this effect is mediated by various properties of HSP70, including its cytoprotective and anti-inflammatory activities. We propose that HSP70 inducers used in a clinical context could prove beneficial for the prevention of UV-induced wrinkle formation.