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

Bone marrow mesenchymal stem cell-derived exosome miR-29b-3p alleviates UV irradiation-induced photoaging in skin fibroblast

BACKGROUND

Mesenchymal stem cells-derived exosome (MSCs-exo) was identified to reduce photoaging. The purpose of this study was to investigate the potential role of microRNA (miR)-29b-3p derived from bone marrow MSCs-exo (BMSCs-exo) in photoaging.

METHODS

Exosomes were isolated from BMSCs and verified by Western blot. A photoaging cell model was constructed by UVB irradiation of human dermal fibroblasts (HDFs). Quantitative real-time PCR (RT-qPCR) was performed to detect the mRNA levels of miR-29b-3p, collagen type I and matrix metalloproteinases (MMPs). CCK-8, Transwell and flow cytometry were applicated to examine cell viability, migration and apoptosis. Commercial kits are used to measure levels of oxidative stress indicators. Finally, a dual-luciferase reporter assay was applied to validate the target of miR-29b-3p.

RESULTS

Extracted exosomes were positive for HSP70 and CD9. Survival of HDFs increased in an exosome concentration-dependent manner. UVB irradiation inhibited miR-29b-3p levels compared with controls, but BMSCs-exo treatment restored miR-29b-3p levels (p < .05). Additionally, BMSCs-exo-miR-29b-3p reversed the inhibition of HDFs migration and oxidative stress by UVB irradiation, as well as the promotion of apoptosis. However, this reversal was attenuated by the suppression of miR-29b-3p (p < .05). Furthermore, BMSCs-exo-miR-29b-3p also inhibited the degradation of collagen type I and the production of MMPs in photoaging, and they were also eliminated by the reduced miR-29b-3p. Finally, MMP-2 was the target gene of miR-29b-3p.

CONCLUSION

Our study presented a novel role for BMSCs-exo-miR-29b-3p in improving skin photoaging function, and these findings may provide new insights into the targeted treatment of skin photoaging.

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.

Attenuation Effect of Radiofrequency Irradiation on UV-B-Induced Skin Pigmentation by Decreasing Melanin Synthesis and through Upregulation of Heat Shock Protein 70

Excess melanin deposition in the skin causes cosmetic problems. HSP70 upregulation decreases microphthalmia-associated transcription factor (MITF) expression, which eventually decreases tyrosinase activity and melanogenesis. Ultraviolet (UV) radiation upregulates p53, which increases the melanocortin receptor (MC1R) and MITF. Furthermore, HSP70 decreases p53 and radiofrequency irradiation (RF) increases HSP70. We evaluated whether RF increased HSP70 and decreased p53, consequently decreasing the MITF/tyrosinase pathway and melanogenesis in UV-B radiated animal skin. Various RF combinations with 50, 100, and 150 ms and 5, 10, and 15 W were performed on the UV-B radiated mouse skin every 2 d for 28 d. When RF was performed with 100 ms/10 W, melanin deposition, evaluated by Fontana–Masson staining, decreased without skin crust formation in the UV-B radiated skin. Thus, we evaluated the effect of RF on decreasing melanogenesis in the HEMn and UV-B radiated skin at a setting of 100 ms/10 W. HSP70 expression was decreased in the UV-B radiated skin but was increased by RF. The expression of p53, MC1R, and MITF increased in the UV-B radiated skin but was decreased by RF. The expression of p53, MC1R, and MITF increased in the α-MSH treated HEMn but was decreased by RF. The decreasing effects of RF on p53, MC1R, CREB and MITF were higher than those of HSP70-overexpressed HEMn. The decreasing effect of RF on p53, MC1R, CREB, and MITF disappeared in the HSP70-silenced HEMn. MC1R, CREB, and MITF were not significantly decreased by the p53 inhibitor in α-MSH treated HEMn. RF induced a greater decrease in MC1R, CREB, and MITF than the p53 inhibitor. Therefore, RF may have decreased melanin synthesis by increasing HSP70 and decreasing p53, thus decreasing MC1R/CREB/MITF and tyrosinase activity.

Peptide location fingerprinting reveals modification-associated biomarker candidates of ageing in human tissue proteomes

Although dysfunctional protein homeostasis (proteostasis) is a key factor in many age-related diseases, the untargeted identification of structurally modified proteins remains challenging. Peptide location fingerprinting is a proteomic analysis technique capable of identifying structural modification-associated differences in mass spectrometry (MS) data sets of complex biological samples. A new webtool (Manchester Peptide Location Fingerprinter), applied to photoaged and intrinsically aged skin proteomes, can relatively quantify peptides and map statistically significant differences to regions within protein structures. New photoageing biomarker candidates were identified in multiple pathways including extracellular matrix organisation (collagens and proteoglycans), protein synthesis and folding (ribosomal proteins and TRiC complex subunits), cornification (keratins) and hemidesmosome assembly (plectin and integrin α6β4). Crucially, peptide location fingerprinting uniquely identified 120 protein biomarker candidates in the dermis and 71 in the epidermis which were modified as a consequence of photoageing but did not differ significantly in relative abundance (measured by MS1 ion intensity). By applying peptide location fingerprinting to published MS data sets, (identifying biomarker candidates including collagen V and versican in ageing tendon) we demonstrate the potential of the MPLF webtool for biomarker discovery.

Probiotic Activity of Staphylococcus epidermidis Induces Collagen Type I Production through FFaR2/p-ERK Signaling

Collagen type I is a key structural component of dermis tissue and is produced by fibroblasts and the extracellular matrix. The skin aging process, which is caused by intrinsic or extrinsic factors, such as natural aging or free radical exposure, greatly reduces collagen expression, thereby leading to obstructed skin elasticity. We investigated the effective fermentation of Cetearyl isononanoate (CIN), a polyethylene glycol (PEG) analog, as a carbon source with the skin probiotic bacterium Staphylococcus epidermidis (S.epidermidis) or butyrate, as their fermentation metabolites could noticeably restore collagen expression through phosphorylated extracellular signal regulated kinase (p-ERK) activation in mouse fibroblast cells and skin. Both the in vitro and in vivo knockdown of short-chain fatty acid (SCFA) or free fatty acid receptor 2 (FFaR2) considerably blocked the probiotic effect of S. epidermidis on p-ERK-induced collagen type I induction. These results demonstrate that butyric acid (BA) in the metabolites of fermenting skin probiotic bacteria mediates FFaR2 to induce the synthesis of collagen through p-ERK activation. We hereby imply that metabolites from the probiotic S. epidermidis fermentation of CIN as a potential carbon source could restore impaired collagen in the dermal extracellular matrix (ECM), providing integrity and elasticity to skin.

The Incidence of Skin Cancer in Relation to Climate Change in South Africa

Climate change is associated with shifts in global weather patterns, especially an increase in ambient temperature, and is deemed a formidable threat to human health. Skin cancer, a non-communicable disease, has been underexplored in relation to a changing climate. Exposure to solar ultraviolet radiation (UVR) is the major environmental risk factor for skin cancer. South Africa is situated in the mid-latitudes and experiences relatively high levels of sun exposure with summertime UV Index values greater than 10. The incidence of skin cancer in the population group with fair skin is considered high, with cost implications relating to diagnosis and treatment. Here, the relationship between skin cancer and several environmental factors likely to be affected by climate change in South Africa are discussed including airborne pollutants, solar UVR, ambient temperature and rainfall. Recommended strategies for personal sun protection, such as shade, clothing, sunglasses and sunscreen, may change as human behaviour adapts to a warming climate. Further research and data are required to assess any future impact of climate change on the incidence of skin cancer in South Africa.

Heat shock protein 70 is a key molecule to rescue imbalance caused by low-frequency noise

A previous study showed that people living in urban areas are generally exposed to low-frequency noise (LFN) with frequencies below 100 Hz and sound levels of 60-110 dB in daily and occupational environments. Exposure to LFN has been shown to affect balance in humans and mice. However, there is no information about prevention of LFN-mediated imbalance because of a lack of information about the target region based on health risk assessment of LFN exposure. Here, we show that acute exposure to LFN at 100 Hz, 95 dB, but not at 85 dB or 90 dB, for only 1 h caused imbalance in mice. The exposed mice also had decreased cervical vestibular-evoked myogenic potential (cVEMP) with impaired activity of vestibular hair cells. Since imbalance in the exposed mice was irreversible, morphological damage in the vestibules of the exposed mice was further examined. The exposed mice had breakage of the otoconial membrane in the vestibule. LFN-mediated imbalance and breakage of the otoconial membrane in mice were rescued by overexpression of a stress-reactive molecular chaperone, heat shock protein 70 (Hsp70), which has been shown to be induced by exposure of mice to 12 h per day of LFN at 95 dB for 5 days. Taken together, the results of this study demonstrate that acute exposure to LFN at 100 Hz, 95 dB for only 1 h caused irreversible imbalance in mice with structural damage of the otoconial membrane as the target region for LFN-mediated imbalance, which can be rescued by Hsp70.

Topical treatment with a cathepsin G inhibitor, β-keto-phosphonic acid, blocks ultraviolet irradiation-induced basement membrane damage in hairless mouse skin

BACKGROUND

Ultraviolet light (UV) exposure contributes various effects to skin including damage of the basement membrane. Cathepsin G (CTSG) belongs to serine protease family, and its upregulation is involved in wrinkle formation by chronic UV irradiation. However, the effect of CTSG on the basement membrane damage in skin remains unclear.

PURPOSE

To investigate the effects of topical treatment with a CTSG inhibitor, β-keto-phosphonic acid (KPA), on basement membrane damage in chronically UV-irradiated hairless mouse skin.

METHODS

The dorsal skin of hairless mice was exposed to UV three times per week for 8 weeks. KPA was applied immediately after each session of UV irradiation. The basement membrane components, CTSG expression, and neutrophil infiltration were analyzed by immunofluorescence staining. The basement membrane structures were visualized by transmission electron microscope. CTSG and MMP-13 protein levels were analyzed by Western blotting. Assessment of wrinkle formation was examined using a skin replica assay.

RESULTS

β-keto-phosphonic acid prevented UV irradiation-induced decrease in type VII collagen, laminin 332, and perlecan at the basement membrane zone and prevented UV-induced breakage of lamina densa and UV-induced shortening of hemidesmosome. KPA prevented UV-induced CTSG and MMP-13 expressions in chronically UV-irradiated hairless mice. Increase in neutrophil infiltration by UV irradiation and UV-induced wrinkle formation was also prevented by KPA.

CONCLUSION

Our present study showed the possible involvement of CTSG in UV-induced basement membrane damage in skin through topical treatment with a CTSG inhibitor, KPA. Thus, inhibition of CTSG may be a useful strategy for the prevention of UV-induced basement membrane damage and photoaging.

A standardized extract of Asparagus officinalis stem prevents reduction in heat shock protein 70 expression in ultraviolet-B-irradiated normal human dermal fibroblasts: an in vitro study

Background

Heat shock protein 70 (HSP70) exhibits protective effects against ultraviolet (UV)-induced premature skin aging. A standardized extract of Asparagus officinalis stem (EAS) is produced as a novel and unique functional food that induces HSP70 cellular expression. To elucidate the anti-photoaging potencies of EAS, we examined its effects on HSP70 expression levels in UV-B-irradiated normal human dermal fibroblasts (NHDFs).

Methods

NHDFs were treated with 1 mg/mL of EAS or dextrin (vehicle control) prior to UV-B irradiation (20 mJ/cm²). After culturing NHDFs for different time periods, HSP70 mRNA and protein levels were analyzed using real-time polymerase chain reaction and western blotting, respectively.

Results

UV-B-irradiated NHDFs showed reduced HSP70 mRNA levels after 1–6 h of culture, which were recovered after 24 h of culture. Treatment with EAS alone for 24 h increased HSP70 mRNA levels in the NHDFs, but the increase was not reflected in its protein levels. On the other hand, pretreatment with EAS abolished the UV-B irradiation-induced reduction in HSP70 expression at both mRNA and protein levels. These results suggest that EAS is capable to preserve HSP70 quantity in UV-B-irradiated NHDFs.

Conclusions

EAS exhibits anti-photoaging potencies by preventing the reduction in HSP70 expression in UV-irradiated dermal fibroblasts.

Electronic supplementary material

The online version of this article (10.1186/s12199-018-0730-3) contains supplementary material, which is available to authorized users.

Skin resistance to UVB-induced oxidative stress and hyperpigmentation by the topical use of Lactobacillus helveticus NS8-fermented milk supernatant

AIMS

In this study, we investigated the preventive properties of the supernatant of Lactobacillus helveticus NS8-fermented milk (NS8-FS) against UV light-induced skin oxidative damage and hyperpigmentation.

METHODS AND RESULTS

NS8-FS exhibited significant radical scavenging activity in tests with ABST⁺ and DPPH scavenging methods, and as well strongly inhibited 3-morpholinosydnonimine (Sin-1)-induced ROS generation in HaCat keratinocytes. Unexpectedly, NS8-FS was found to inhibit melanin production in B16F10 melanoma cells and to exhibit inhibitory effects both to the enzymatic activity of tyrosinase (TYR) and the expression of proteins required for melanin synthesis. In SKH-1 hairless mice, topical application of NS8-FS alleviated UVB-induced skin photodamage, including the improvement of the appearance of epidermal thickness, transepidennal water loss and lipid peroxidation levels. In the tanning guinea pig model, the whitening effect of NS8-FS was demonstrated using Masson-Fontana staining and TYR staining. Furthermore, NS8-FS was shown to stimulate the nuclear translocation and activation of the Nrf2 protein, along with recovery of antioxidant enzyme activities.

CONCLUSION

NS8-FS exhibits the protective capacities against UV light-induced skin oxidative damage and hyperpigmentation.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our findings indicate the potential of cell-free fermented products of lactic acid bacteria in topical photoprotection.

Protective effects of compounds from Garcinia mangostana L. (mangosteen) against UVB damage in HaCaT cells and hairless mice

Ultraviolet B (UVB) radiation causes alterations in the skin, such as epidermal thickening, wrinkle formation and inflammation. Therefore, preventing UVB-induced skin damage can promote general health among the human population. Garcinia mangostana L. (mangosteen) is a fruit that has become a popular botanical dietary supplement because of its perceived role in promoting overall health. The present study investigated the photoprotective effects of α-, β-, γ-mangostins and gartanin against UVB radiation using the HaCaT immortalized human keratinocyte cell line as an in vitro model and hairless mice as an in vivo model. UVB radiation increased the expression of matrix metalloproteinase (MMP)‑1 and ‑9 and decreased the mRNA expression levels of involucrin, filaggrin and loricrin in HaCaT cells; however, these changes were attenuated by pretreating the cells with α-, β-, γ-mangostins and gartanin. Among these compounds, α-mangostin exhibited the greatest effects in reducing UVB-induced skin wrinkles, inhibited epidermal thickening in hairless mice in vivo. Exposure to UVB radiation increased the expression of MMPs and pro-inflammatory cytokines and activated mitogen-activated protein kinases in hairless mice, but these changes were attenuated by α-mangostin. The authors suggested that α-mangostin exerts anti-wrinkle and anti-aging properties.

Protective effects of Aloe sterols against UVB-induced photoaging in hairless mice

BACKGROUND

Aloe vera is a traditional medical plant whose gel has been widely used in skin care. Previously, we have identified Aloe sterols from Aloe vera as active ingredients. This study investigated the protective effects of Aloe sterols without polysaccharides, against ultraviolet B (UVB)-induced skin photoaging in mice using Aloe vera gel extract (AVGE) obtained by supercritical fluid extraction.

METHODS

Aloe vera gel extract was supplemented in the diet (12 or 120 ppm), and HR-1 hairless mice were exposed to UVB irradiation for 7 weeks. Skin measurements and histological and analytical studies were performed.

RESULTS

Repeated UVB irradiation induced rough wrinkling of skin with water content reduction and hyperkeratosis. AVGE administration resulted in the significant improvement of UVB-induced skin dryness, epidermal thickness, and wrinkle formation. The AVGE group also suppressed the degenerations of dermal collagen fibers and the appearance of cutaneous apoptosis cells induced by UVB. Furthermore, AVGE administration reduced the excess elevation of pro-inflammatory cytokines (IL-1β and TNF-α) and matrix metalloproteinases (MMP-2, MMP-9, MMP-12, and MMP-13) in UVB-exposed skin.

CONCLUSION

The dietary ingestion of Aloe sterols protected against chronic UVB damage in mouse skin, and our results suggest that Aloe sterols may prevent skin photoaging through the anti-inflammation and MMP regulation.

Variation in Hsp70-1A Expression Contributes to Skin Color Diversity

The wide range in human skin color results from varying levels of the pigment melanin. Genetic mechanisms underlying coloration differences have been explored, but identified genes do not account for all variation seen in the skin color spectrum. Post-transcriptional and post-translational regulation of factors that determine skin color, including melanin synthesis in epidermal melanocytes, melanosome transfer to keratinocytes, and melanosome degradation, is also critical for pigmentation. We therefore investigated proteins that are differentially expressed in melanocytes derived from either white or African American skin. Two-dimensional gel electrophoresis and mass spectrometry demonstrated that heat shock protein 70-1A (Hsp70-1A) protein levels were significantly higher in African American melanocytes compared with white melanocytes. Hsp70-1A expression significantly correlated with levels of tyrosinase, the rate-limiting melanogenic enzyme, consistent with a proposed role for Hsp70 family members in tyrosinase post-translational modification. In addition, pharmacologic inhibition and small interfering RNA-mediated downregulation of Hsp70-1A correlated with pigmentation changes in cultured melanocytes, modified human skin substitutes, and ex vivo skin. Furthermore, Hsp70-1A inhibition led to increased autophagy-mediated melanosome degradation in keratinocytes. Our data thus reveal that epidermal Hsp70-1A contributes to the diversity of skin color by regulating the amount of melanin synthesized in melanocytes and modulating autophagic melanosome degradation in keratinocytes.

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.

Exposure to non-extreme solar UV daylight: spectral characterization, effects on skin and photoprotection

The link between chronic sun exposure of human skin and harmful clinical consequences such as photo-aging and skin cancers is now indisputable. These effects are mostly due to ultraviolet (UV) rays (UVA, 320–400 nm and UVB, 280–320 nm). The UVA/UVB ratio can vary with latitude, season, hour, meteorology and ozone layer, leading to different exposure conditions. Zenithal sun exposure (for example on a beach around noon under a clear sky) can rapidly induce visible and well-characterized clinical consequences such as sunburn, predominantly induced by UVB. However, a limited part of the global population is exposed daily to such intense irradiance and until recently little attention has been paid to solar exposure that does not induce any short term clinical impact. This paper will review different studies on non-extreme daily UV exposures with: (1) the characterization and the definition of the standard UV daylight and its simulation in the laboratory; (2) description of the biological and clinical effects of such UV exposure in an in vitro reconstructed human skin model and in human skin in vivo, emphasizing the contribution of UVA rays and (3) analysis of photoprotection approaches dedicated to prevent the harmful impact of such UV exposure.

The hallmarks of fibroblast ageing

Ageing is influenced by the intrinsic disposition delineating what is maximally possible and extrinsic factors determining how that frame is individually exploited. Intrinsic and extrinsic ageing processes act on the dermis, a post-mitotic skin compartment mainly consisting of extracellular matrix and fibroblasts. Dermal fibroblasts are long-lived cells constantly undergoing damage accumulation and (mal-)adaptation, thus constituting a powerful indicator system for human ageing. Here, we use the systematic of ubiquitous hallmarks of ageing (Lopez-Otin et al., 2013, Cell 153) to categorise the available knowledge regarding dermal fibroblast ageing. We discriminate processes inducible in culture from phenomena apparent in skin biopsies or primary cells from old donors, coming to the following conclusions: (i) Fibroblasts aged in culture exhibit most of the established, ubiquitous hallmarks of ageing. (ii) Not all of these hallmarks have been detected or investigated in fibroblasts aged in situ (in the skin). (iii) Dermal fibroblasts aged in vitro and in vivo exhibit additional features currently not considered ubiquitous hallmarks of ageing. (iv) The ageing process of dermal fibroblasts in their physiological tissue environment has only been partially elucidated, although these cells have been a preferred model of cell ageing in vitro for decades.

Adaptive and maladaptive responses in skin: mild heat exposure protects against UVB-induced photoaging in mice

In this issue, Matsuda et al. demonstrate the protective effect of mild heat preconditioning on UVB-induced photoaging in SKH-1 hairless mice. Mild heat exposure stimulates the upregulation of HSP70 chaperones, which inhibit the activities of matrix-degenerating enzymes, thereby avoiding wrinkle formation. This newly identified heat-mediated process of adaptation to UVB radiation exposure opens new opportunities to slow extrinsic skin aging.