Resveratrol couples apoptosis with autophagy in UVB-irradiated HaCaT cells

Probucol-bile acid based nanoparticles protect auditory cells from oxidative stress: an in vitro study

Aim: Excessive free radicals contribute to oxidative stress and mitochondrial dysfunction in sensorineural hearing loss (SNHL). The antioxidant probucol holds promise, but its limited bioavailability and inner ear barriers hinder effective SNHL treatment. Methodology: We addressed this by developing probucol-loaded nanoparticles with polymers and lithocholic acid and tested them on House Ear Institute-Organ of Corti cells. Results: Probucol-based nanoparticles effectively reduced oxidative stress-induced apoptosis, enhanced cellular viability, improved probucol uptake and promoted mitochondrial function. Additionally, they demonstrated the capacity to reduce reactive oxygen species through the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 pathway. Conclusion: This innovative nanoparticle system holds the potential to prevent oxidative stress-related hearing impairment, providing an effective solution for SNHL.

Chaga Medicinal Mushroom, Inonotus obliquus (Agaricomycetes), Polysaccharides Alleviate Photoaging by Regulating Nrf2 Pathway and Autophagy

Inonotus obliquus is a medicinal mushroom that contains the valuable I. obliquus polysaccharides (IOP), which is known for its bioactive properties. Studies have shown that IOP could inhibit oxidative stress induced premature aging and DNA damage, and delay body aging. However, the molecular mechanism of IOP in improving skin photoaging remains unclear, which prevents the development and utilization of I. obliquus in the field of skin care. In this study, ultraviolet B (UVB) induced human immortalized keratinocyte (HaCaT) cell photoaging model was used to explore the mechanism of IOP in relieving skin photoaging. Results showed that IOP inhibited cell senescence and apoptosis by reducing the protein expressions of p16, p21, and p53. IOP increased HO-1, SOD, and CAT expressions to achieve Nrf2/HO-1 pathway, thus improving antioxidant effects and preventing ROS generation. Furthermore, IOP enhanced the expression levels of p-AMPK, LC3B, and Beclin-1 to alleviate the autophagy inhibition in UVB-induced HaCaT cells. Based on these findings, our data suggested that IOP may be used to develop effective natural anti-photoaging ingredients to promote skin health.

Modulation of autophagy, apoptosis and oxidative stress: a clue for repurposing metformin in photoaging

Long-term sun exposure is the commonest cause of photoaging, where mutual interplay between autophagy, oxidative stress, and apoptosis is incriminated. In combating photoaging, pharmacological approaches targeted to modulate autophagy are currently gaining more ground. This study aimed to examine repurposing metformin use in such context with or without the antioxidant coenzyme Q10 (coQ10) in ultraviolet A (UVA) irradiation-induced skin damage. The study was conducted on 70 female CD1 mice that were randomly assigned into seven groups (10/group): normal control, vehicle-treated-UVA-exposed mice, three metformin UVA-exposed groups (Topical 1 and 10%, and oral 300 mg/kg), topical coQ10 (1%)-treated mice, and combined oral metformin with topical coQ10-treated UVA-exposed mice. After UVA-exposure for 10 weeks (3 times/week), macroscopic signs of photoaging were evaluated. Mice were then euthanized, and the skin was harvested for biochemical estimation of markers for oxidative stress, inflammation, matrix breakdown, and lysosomal function. Histopathological signs of photoaging were also evaluated with immunohistochemical detection of associated changes in autophagic and apoptotic markers. Metformin, mainly by topical application, improved clinical and histologic signs of photoaging. This was associated with suppression of the elevated oxidative stress, IL-6, matrix metalloproteinase 1, and caspase, with induction of cathepsin D and subsequent change in anti-LC3 and P62 staining in skin tissue. In addition to metformin antioxidant, anti-inflammatory, and antiapoptotic activities, its anti-photoaging effect is mainly attributed to enhancing autophagic flux by inducing cathepsin D. Its protective effect is boosted by coQ10, which supports their potential use in photoaging.

Oxidative Stress and Autophagy as Key Targets in Melanoma Cell Fate

Melanoma originates from the malignant transformation of melanocytes and is one of the most aggressive forms of cancer. The recent approval of several drugs has increased the chance of survival although a significant subset of patients with metastatic melanoma do not show a long-lasting response to these treatments. The complex cross-talk between oxidative stress and the catabolic process autophagy seems to play a central role in all aspects of melanoma pathophysiology, from initiation to progression and metastasis, including drug resistance. However, determining the fine role of autophagy in cancer death and in response to redox disruption is still a fundamental challenge in order to advance both basic and translational aspects of this field. In order to summarize the interactions among reactive oxygen and nitrogen species, autophagy machinery and proliferation/growth/death/apoptosis/survival, we provide here a narrative review of the preclinical evidence for drugs/treatments that modulate oxidative stress and autophagy in melanoma cells. The significance and the potential for pharmacological targeting (also through multiple and combination approaches) of these two different events, which can contribute independently or simultaneously to the fate of melanoma, may help to define new processes and their interconnections underlying skin cancer biology and unravel new reliable approaches.

Autophagy in skin barrier and immune-related skin diseases

Autophagy is a process which is highly conserved in eukaryotes to degrade or recycle cytoplasmic components through lysosomes to maintain cellular homeostasis. Recent studies have shown that autophagy also plays critical roles in cell apoptosis, inflammation, pathogen clearance, and so on under stressed conditions and thereby has been linked to a variety of human disorders. The skin is the largest organ of the body and serves as the first line of defense against environmental insult. Skin as a nutrient-poor environment requires recycling of limited resources via the autophagy machinery to maintain homeostasis. Therefore, dysregulation of autophagy has been linked to skin diseases. In this review, we describe the molecular machinery and regulation of autophagy, discuss its role in keratinocytes and skin barrier, skin immune cells, and immune-related skin diseases including autoimmune skin disorders, allergic skin diseases, infectious skin disorders, and antitumor immunity against skin tumor. Finally, we highlight the potential of autophagy as a therapeutic target for immune-related skin diseases, and delivery of autophagy-related molecules (such as inducers, inhibitors, or nucleic acid molecules) by virtue of physical materials (such as nanoparticles) or biological materials (such as peptides) to skin topically may obtain clinical benefits in immune-related skin diseases. Moreover, developing autophagy-related gene product-based biomarkers may be promising to diagnose immune-related skin diseases.

Determination of in vivo virtue of dermal targeted combinatorial lipid nanocolloidal based formulation of 5-fluorouracil and resveratrol against skin cancer

The current study has been designed to appraise the efficacy of developed combinatorial lipid-nanosystem-based gel (linogel) of 5-fluorouracil and resveratrol for skin cancer treatment. Initially, linogel was prepared and characterized for different parameters, namely pH, texture, drug content uniformity, occlusiveness, etc. Then in vivo efficacy studies (tumor number, area, and volume, histopathology, ultrastructural and immunohistochemical analysis) of linogel were determined over-developed skin tumors. Developed linogel possessed significantly (p < 0.05) better texture and occlusiveness than conventional gel formulation. Decreased tumor number, area, and volume showed significant results (p < 0.05) in favor of linogel. Histopathological and ultrastructural analysis confirmed superior efficacy of linogel in terms of marked improvement in the nucleus and subcellular structures in photomicrographs. The antioxidants and anti-inflammatory analysis findings showed a significantly (p < 0.05) potent effectiveness of linogel. The apoptotic and anti-proliferation activity of linogel was confirmed by analysis of caspase-3 and ki-67, which showed significant (p < 0.05) elevation in the level of cleaved caspase-3 and reduction in the level of ki-67 than untreated and conventional gel formulation treated tumors, indicating antitumor effect due to cancerous cell death. Thus, developed linogel fulfilled all the criteria of dermal application and exhibited efficacious therapeutic results, which could be a beneficial therapeutic approach against skin cancer.

A topical formulation containing quercetin-loaded microcapsules protects against oxidative and inflammatory skin alterations triggered by UVB irradiation: enhancement of activity by microencapsulation

Ultraviolet B (UVB) irradiation causes free radical production, increase inflammation and oxidative stress, thus, supporting the use of antioxidants by topical administration as therapeutic approaches. Quercetin (QC) is a flavonoid with antioxidant activity, however, high liposolubility makes it difficult to remain in the viable skin layer. Thus, this study evaluated whether microencapsulation of QC would enhance its activity in comparison with the same dose of free QC (non-active dose) and unloaded-microcapsules added in formulation for topical administration in a mouse model of UVB irradiation targeting the skin. Topical formulation containing Quercetin-loaded microcapsules (TFcQCMC) presents physico-chemical (colour, consistence, phase separation and pH) and functional antioxidant stability at 4 °C, room temperature and 40 °C for 6 months. TFcQCMC inhibited the UVB-triggered depletion of antioxidants observed by GSH (reduced glutathione), ability to reduce iron, ability to scavenge 2,2'-azinobis radical and catalase activity. TFcQCMC also inhibited markers of oxidation (lipid hydroperoxides and superoxide anion production). Concerning inflammation, TFcQCMC reduced the production of inflammatory cytokines, matrix metalloproteinase-9 activity, skin edoema, collagen fibre damage, myeloperoxidase activity/neutrophil recruitment, mast cell and sunburn cell counts. The pharmacological activity of TFcQCMC was not shared by the same pharmaceutical form containing the same dose of free QC or unloaded control microcapsules.

Inhibitors of Nucleotide Excision Repair Decrease UVB-Induced Mutagenesis-An In Vitro Study

The high incidence of skin cancers in the Caucasian population is primarily due to the accumulation of DNA damage in epidermal cells induced by chronic ultraviolet B (UVB) exposure. UVB-induced DNA photolesions, including cyclobutane–pyrimidine dimers (CPDs), promote mutations in skin cancer driver genes. In humans, CPDs are repaired by nucleotide excision repair (NER). Several commonly used and investigational medications negatively influence NER in experimental systems. Despite these molecules’ ability to decrease NER activity in vitro, the role of these drugs in enhancing skin cancer risk is unclear. In this study, we investigated four molecules (veliparib, resveratrol, spironolactone, and arsenic trioxide) with well-known NER-inhibitory potential in vitro, using UVB-irradiated CHO epithelial and HaCaT immortalized keratinocyte cell lines. Relative CPD levels, hypoxanthine phosphoribosyltransferase gene mutation frequency, cell viability, cell cycle progression, and protein expression were assessed. All four molecules significantly elevated CPD levels in the genome 24 h after UVB irradiation. However, veliparib, spironolactone, and arsenic trioxide reduced the mutagenic potential of UVB, while resveratrol did not alter UVB-induced mutation formation. UVB-induced apoptosis was enhanced by spironolactone and arsenic-trioxide treatment, while veliparib caused significantly prolonged cell cycle arrest and increased autophagy. Spironolactone also enhanced the phosphorylation level of mammalian target of rapamycin (mTOR), while arsenic trioxide modified UVB-driven mitochondrial fission. Resveratrol induced only mild changes in the cellular UVB response. Our results show that chemically inhibited NER does not result in increased mutagenic effects. Furthermore, the UVB-induced mutagenic potential can be paradoxically mitigated by NER-inhibitor molecules. We identified molecular changes in the cellular UVB response after NER-inhibitor treatment, which may compensate for the mitigated DNA repair. Our findings show that metabolic cellular response pathways are essential to consider in evaluating the skin cancer risk–modifying effects of pharmacological compounds.

Differential Modulation of Autophagy Contributes to the Protective Effects of Resveratrol and Co-Enzyme Q10 in Photoaged Mice

BACKGROUND

In photoaging, the accumulation of ultraviolet (UV)-induced oxidative damage leads to the characteristic hallmarks of aging. Here arises the importance of autophagy as a cellular degradation process that cleans the cells of defective or aged organelles and macromolecules, thus maintaining cellular homeostasis. In spite of this, the exact impact of autophagy in photoaging is still elusive.

OBJECTIVE

To evaluate the protective effects of resveratrol and/or co-enzyme-Q10 against the UVA-induced alterations and to explore the role of autophagy in their proposed benefits.

METHODS

Sixty female mice were randomly divided into normal control, untreated UVA-exposed, resveratrol (50mg/kg), co-enzyme-Q10 (100mg/kg), and resveratrol/co-enzyme-Q10-treated UVA-- exposed groups. Clinical signs of photoaging were evaluated using a modified grading score and the pinch test. Skin malondialdehyde and reduced glutathione were assessed as markers of oxidative stress. Tissues were examined for histopathological signs of photodamage, and autophagic changes were determined by immunohistochemical detection of LC3 and P62 in the different cells of the skin.

RESULTS

UVA-exposure increased the oxidative stress with subsequent epidermal and dermal injury. This was associated with the stimulation of autophagy in the keratinocytes and inhibition of autophagic flux in the fibroblasts and infiltrating macrophages. Both drugs corrected the impaired pinch test, macro-and microscopic changes, and exhibited distinct staining patterns with anti-LC3 and P62 in the different cell types denoting autophagic modulation.

CONCLUSION

Changes in autophagic flux are strongly implicated in photoaging associated skin damage and the differential modulation of autophagy by resveratrol and, to a lesser extent by Co-enzyme- Q10, is partially involved in their therapeutic benefits.

Antioxidants as an Epidermal Stem Cell Activator

Antioxidants may modulate the microenvironment of epidermal stem cells by reducing the production of reactive oxygen species or by regulating the expression of extracellular matrix protein. The extracellular membrane is an important component of the stem cell niche, and microRNAs regulate extracellular membrane-mediated basal keratinocyte proliferation. In this narrative review, we will discuss several antioxidants such as ascorbic acid, plant extracts, peptides and hyaluronic acid, and their effect on the epidermal stem cell niche and the proliferative potential of interfollicular epidermal stem cells in 3D skin equivalent models.

The Lipoxin Receptor/FPR2 Agonist BML-111 Protects Mouse Skin Against Ultraviolet B Radiation

Excessive exposure to UV, especially UVB, is the most important risk factor for skin cancer and premature skin aging. The identification of the specialized pro-resolving lipid mediators (SPMs) challenged the preexisting paradigm of how inflammation ends. Rather than a passive process, the resolution of inflammation relies on the active production of SPMs, such as Lipoxins (Lx), Maresins, protectins, and Resolvins. LXA4 is an SPM that exerts its action through ALX/FPR2 receptor. Stable ALX/FPR2 agonists are required because SPMs can be quickly metabolized within tissues near the site of formation. BML-111 is a commercially available synthetic ALX/FPR2 receptor agonist with analgesic, antioxidant, and anti-inflammatory properties. Based on that, we aimed to determine the effect of BML-111 in a model of UVB-induced skin inflammation in hairless mice. We demonstrated that BML-111 ameliorates the signs of UVB-induced skin inflammation by reducing neutrophil recruitment and mast cell activation. Reduction of these cells by BML-111 led to lower number of sunburn cells formation, decrease in epidermal thickness, collagen degradation, cytokine production (TNF-α, IL-1β, IL-6, TGF, and IL-10), and oxidative stress (observed by an increase in total antioxidant capacity and Nrf2 signaling pathway), indicating that BML-111 might be a promising drug to treat skin disorders.

Role of Resveratrol in Regulating Cutaneous Functions

Protective role of the skin is against external insults and maintenance of electrolyte homeostasis of the body. Cutaneous dysfunction can account for the development of both cutaneous and systemic disorders. Thus, improvements in cutaneous functions can benefit a number of extracutaneous and cutaneous functions. Resveratrol, a natural ingredient, displays multiple benefits for various systems/organs, including the skin. The benefits of resveratrol for cutaneous functions include stimulation of keratinocyte differentiation and antimicrobial peptide expression, inhibition of keratinocyte proliferation and cutaneous inflammation, UV protection, anticancer, antiaging, and inhibition of melanogenesis. The mechanisms of action of resveratrol include activation of sirtuin 1 and nuclear factor erythroid 2-related factor 2, and inhibition of mitogen-activated protein kinase signaling. Evidence suggests that topical resveratrol could be a valuable alternative not only for daily skin care, but also for the prevention and treatment of various cutaneous disorders. This review summarizes the benefits of resveratrol for cutaneous functions.

Photoprotection of maqui berry against ultraviolet B-induced photodamage in vitro and in vivo

Maqui berry extracts could ameliorate oxidative stress, cellular DNA damage, and inflammation induced by UVB-irradiation in vitro and in vivo.

NF-κB-Mediated Neuroinflammation in Parkinson's Disease and Potential Therapeutic Effect of Polyphenols

Different animal and human studies from last two decades in the case of Parkinson's disease (PD) have concentrated on oxidative stress due to increased inflammation and cytokine-dependent neurotoxicity leading to induction of dopaminergic (DA) degeneration pathway in the nigrostriatal region. Chronic inflammation, the principle hallmark of PD, forms the basis of neurodegeneration. Aging in association with activation of glia due to neuronal injury, perhaps because of immune alterations and genetic predispositions, leads to deregulation of inflammatory pathways premising the onset of PD. A family of inducible transcription factors, nuclear factor-κB (NF-κB), is found to show expression in various cells and tissues, such as microglia, neurons, and astrocytes which play an important role in activation and regulation of inflammatory intermediates during inflammation. Both canonical and non-canonical NF-κB pathways are involved in the regulation of the stimulated cells. During the prodromal/asymptomatic stage of age-associated neurodegenerative diseases (i.e., PD and AD), chronic neuroinflammation may act silently as the driver of neuronal dysfunction. Though research has provided an insight over age-related neurodegeneration in PD, elaborative role of NF-κB in neuroinflammation is yet to be completely understood and thus requires more investigation. Polyphenols, a group of naturally occurring compound in medicinal plants, have gained attention because of their anti-oxidative and anti-neuroinflammatory properties in neurodegenerative diseases. In this aspect, this review highlights the role of NF-κB and the possible therapeutic roles of polyphenols in NF-κB-mediated neuroinflammation in PD.

Double knock-out of Hmga1 and Hipk2 genes causes perinatal death associated to respiratory distress and thyroid abnormalities in mice

The serine–threonine kinase homeodomain-interacting protein kinase 2 (HIPK2) modulates important cellular functions during development, acting as a signal integrator of a wide variety of stress signals, and as a regulator of transcription factors and cofactors. We have previously demonstrated that HIPK2 binds and phosphorylates High-Mobility Group A1 (HMGA1), an architectural chromatinic protein ubiquitously expressed in embryonic tissues, decreasing its binding affinity to DNA. To better define the functional role of HIPK2 and HMGA1 interaction in vivo, we generated mice in which both genes are disrupted. About 50% of these Hmga1/Hipk2 double knock-out (DKO) mice die within 12 h of life (P1) for respiratory failure. The DKO mice present an altered lung morphology, likely owing to a drastic reduction in the expression of surfactant proteins, that are required for lung development. Consistently, we report that both HMGA1 and HIPK2 proteins positively regulate the transcriptional activity of the genes encoding the surfactant proteins. Moreover, these mice display an altered expression of thyroid differentiation markers, reasonably because of a drastic reduction in the expression of the thyroid-specific transcription factors PAX8 and FOXE1, which we demonstrate here to be positively regulated by HMGA1 and HIPK2. Therefore, these data indicate a critical role of HIPK2/HMGA1 cooperation in lung and thyroid development and function, suggesting the potential involvement of their impairment in the pathogenesis of human lung and thyroid diseases.

Improved extraction of resveratrol and antioxidants from grape peel using heat and enzymatic treatments

BACKGROUND

Resveratrol, an extensively recognized phytochemical that belongs to the stilbene family, is abundant in grape peel which is discarded as a by-product during grape juice processing.

RESULTS

In this study, we established that pre-heating grape peel above 75 °C significantly improved the extractability of resveratrol and its glucoside piceid. In particular, thermal heating of grape peel at 95 °C for 10 min, followed by treatment with a mixture of exo-1,3-β-glucanase and pectinases at 50 °C for 60 min, dramatically increased the conversion of piceid into resveratrol and the overall extractability of this phytochemical by 50%. Furthermore, thermal pre-treatment promoted a substantial increase in the total phenol, flavonoid, and anthocyanin concentrations in the grape peel extract. Ultimately, resveratrol-enriched grape peel extract significantly augmented the antioxidant response in vitro, possibly by attenuating the accumulation of intracellular reactive oxygen species via the Nrf2 signaling pathway.

CONCLUSION

The method developed in this study for preparing grape peel extract introduces a potential low-cost green processing for the industrial fortification of food products with resveratrol and other health-beneficial antioxidants. © 2019 Society of Chemical Industry.

Insights into autophagy machinery in cells related to skin diseases and strategies for therapeutic modulation

Autophagy, literally meaning "self-eating," is a highly conserved process that is part of the eukaryotic cell cycle. Morphologically, the double membrane contains vesicles with phagocytic components known as autophagosomes. Autophagy is often used as a cellular stress response and quality control mechanisms are used to maintain cell survival. Survival is facilitated by providing energy and metabolic precursors as well as removing damaged proteins or organelles. Moreover, autophagy refers to organelles fused together with part of the cell cytoplasm with a double or multi-membrane structure called phagosome. Research has demonstrated that autophagy is an important mediator of cell fate and has effects on inflammation, pathogen clearance, and antigen presentation. In recent years, studies discussing autophagy have increased in number. Nevertheless, only a small amount of research has considered the impact of autophagy on the pathogenesis of skin diseases. The skin is the largest organ of the body, with a surface area of around two square metre; it is the first line of defense against numerous environmental insults, including ultraviolet radiation, pathogens, mechanical stresses, and toxic chemicals. Autophagy is thought to be a vital modality for endogenous defenses against environmental derangements. This review provides an overview of autophagy machinery in keratinocytes, skin fibroblasts, melanocytes related to skin diseases as well as strategies for therapeutic modulation, for the future development of treatment for skin diseases.

Treatment with maresin 1, a docosahexaenoic acid-derived pro-resolution lipid, protects skin from inflammation and oxidative stress caused by UVB irradiation

Acute exposure to UVB irradiation causes skin inflammation and oxidative stress, and long-term exposure to UVB irradiation may lead to carcinogenesis. Our organism has endogenous mechanisms to actively limit inflammation. Maresin 1 (MaR1; 7R,14S-dihydroxy-docosa-4Z,8E,10E,12Z,16Z,19Z-hexaenoic acid) is a pro-resolution lipid mediator derived from the docosahexaenoic acid, which presents anti-inflammatory and pro-resolution effects. However, it remains to be determined if treatment with MaR1 can inhibit inflammatory and oxidative alterations in the skin triggered by UVB. The treatment with MaR1 (0.1-10 ng/mice at -10 min relative to the UVB irradiation protocol) reduced UVB-induced skin edema, neutrophil recruitment (MPO; myeloperoxidase activity, and migration of LysM-eGFP⁺ cells), cytokine production, matrix metalloproteinase-9 activity, keratinocyte apoptosis, epidermal thickening, mast cells counts and degradation of skin collagen in hairless mice. UVB irradiation caused a decrease of GSH (reduced glutathione) levels, activity of the enzyme catalase, ferric reducing ability (FRAP), and ABTS radical scavenging capacity as well as induced lipid hydroperoxide, superoxide anion production, and gp91^phox mRNA expression. These parameters that indicate oxidative stress were inhibited by MaR1 treatment. Therefore, these data suggest MaR1 as a promising pharmacological tool in controlling the deleterious effects related to UVB irradiation.

Resveratrol as a Multifunctional Topical Hypopigmenting Agent

Melanin is produced in melanocytes and stored in melanosomes, after which it is transferred to keratinocytes and, thus, determines skin color. Despite its beneficial sun-protective effects, abnormal accumulation of melanin results in esthetic problems. A range of topical hypopigmenting agents have been evaluated for their use in the treatment of pigmentary disorders with varying degrees of success. Hydroquinone (HQ), which competes with tyrosine, is the main ingredient in topical pharmacological agents. However, frequent occurrence of adverse reactions is an important factor that limits its use. Thus, efforts to discover effective topical hypopigmenting agents with less adverse effects continue. Here, we describe the potential of resveratrol to function as an effective hypopigmenting agent based on its mechanism of action. Resveratrol is not only a direct tyrosinase inhibitor but an indirect inhibitor as well. Additionally, it can affect keratinocytes, which regulate the function of melanocytes. Resveratrol regulates the inflammatory process of keratinocytes and protects them from oxidative damage. In this way, it prevents keratinocyte-induced melanocyte stimulation. Furthermore, it has a rescuing effect on the stemness of interfollicular epidermal cells that can repair signs of photoaging in the melasma, a typical pigmentary skin disorder. Overall, resveratrol is a promising potent hypopigmenting agent.

Resveratrol attenuates hydrogen peroxide-induced aging through upregulation of autophagy in human umbilical vein endothelial cells

PURPOSE

Resveratrol (RESV; trans-3,5,4'-trihydroxystilbene) has emerged as a potential new therapeutic for age-related atherosclerotic diseases. However, the effect of RESV on cellular aging and its underlying mechanisms remain unknown. Therefore, the aim of this study was to examine whether RESV can delay cellular aging through upregulation of autophagy.

MATERIALS AND METHODS

Human umbilical endothelial vein cells (HUVECs) were divided into four groups: the control group, and the hydrogen peroxide (H2O2) alone, H2O2 + RESV pretreatment, and H2O2 + 3-methyladenine (3-MA) + RESV pretreatment intervention groups. The cell viability was evaluated by a cell counting kit-8 assay. Superoxide dismutase (SOD) activity and intracellular reactive oxygen species (ROS) levels were tested using commercial kits. Senescence-related β-galactosidase activities were detected by immunohistochemical staining. The expression levels of aging-related and autophagy-related markers, including phosphorylated Rb (p-Rb), LC3, and p62, with or without RESV were measured by Western blotting.

RESULTS

Pretreatment with 10 µM RESV increased the cell viability and SOD levels. The remarkably higher positive rate of senescence-associated β-galactosidase and increased intracellular ROS levels in the H2O2 treatment group were reversed by treatment with 10 µM RESV. As compared to the H2O2 treatment group, 10 µM RESV could upregulate autophagy through the regulation of p-Rb, LC3, and p62 levels. The anti-aging effect of RESV via an autophagy regulation mechanism was further confirmed by the suppression of these effects with 3-MA treatment.

CONCLUSION

RESV may reverse and delay the aging process of HUVECs via upregulation of autophagy and could be a candidate therapeutic for age-related atherosclerotic diseases.

Modulation of Autophagy for Controlling Immunity

Autophagy is an essential process that maintains physiological homeostasis by promoting the transfer of cytoplasmic constituents to autophagolysosomes for degradation. In immune cells, the autophagy pathway plays an additional role in facilitating proper immunological functions. Specifically, the autophagy pathway can participate in controlling key steps in innate and adaptive immunity. Accordingly, alterations in autophagy have been linked to inflammatory diseases and defective immune responses against pathogens. In this review, we discuss the various roles of autophagy signaling in coordinating immune responses and how these activities are connected to pathological conditions. We highlight the therapeutic potential of autophagy modulators that can impact immune responses and the mechanisms of action responsible.

The preventive effect of deep sea water on the development of cancerous skin cells through the induction of autophagic cell death in UVB-damaged HaCaT keratinocyte

Ultraviolet light (UV) is a major inducer of skin cancer. Therefore, recovery and removal of UV-damaged skin cells are important in the prevention of skin carcinogenesis. Here, we investigated the effect of deep sea water (DSW) in HaCaT keratinocyte exposed by UVB (λ = 290∼320 nm). The result showed that UVB-induced cell death was reinforced by DSW treatment in a hardness-dependent manner. Furthermore, the increase of cell death by DSW was associated with the down-regulation of survivin and RAD51 expressions induced by UVB. Moreover, we confirmed the inhibition of H2 A.X phosphorylation, a marker for double-stranded DNA damage, and the enhancement of LC3-II and SQSTM1/p62 expressions by DSW administration in UVB-radiated HaCaT keratinocyte. The results imply that the enhancement of UVB-induced cell death by DSW is associated with autophagy. Therefore, we further explored the regulation of autophagy-regulating proteins and apoptosis-related factors expression. Phosphorylation of mammalian target of rapamycin (mTOR), ribosomal protein S6, and S6 kinase by UVB radiation were regressed via DSW treatment, underlying the increase of AMP-activated protein kinase (AMPK) phosphorylation. Furthermore, UVB-enhanced nuclear factor κB (NF-κB) and c-Jun N-terminal kinase (JNK) phosphorylations were increased with DSW treatment. Contrastingly, DSW lessened the Ser15 phosphorylation of p53 and cleavage of poly (ADP-ribose) polymerase induced by UVB radiation. Consequently, the results demonstrate that DSW enhances UVB-damaged skin cell clearance through the activation of autophagic cell death underlying the regulation of AMP-activated protein kinase (AMPK)/mTOR signaling as well as NF-κB and JNK phosphorylations. In conclusion, this investigation suggests that DSW is a potent candidate for the prevention of UV-induced skin cancer development.

Klotho Protein Protects Human Keratinocytes from UVB-Induced Damage Possibly by Reducing Expression and Nuclear Translocation of NF-κB

Background

UV-related skin disease such as actinic keratosis is a major concern in public health. In view of the cell injury induced by UVB, Klotho protein it is an ideal therapy to eliminate UVB-induced cell damages and the associated signaling pathways.

Material/Methods

To gain insights into the potential role of Klotho and the underlying molecular mechanism, we constructed a Klotho-overexpress HaCaT cell line and assessed the protection against UVB insults. The effects of exposure to UVB radiation on the human keratinocyte HaCaT cells, including cell growth, apoptosis, and changes of selected biomarkers, were measured by CCK-8, flow cytometry, Quantitative real-time PCR, and Western blot analysis.

Results

We found that enhanced NF-κB activity was accompanied by decreased expression of the anti-aging protein Klotho upon UVB stimulation, which was further confirmed with in vivo experiments. Overexpression of Klotho was able to considerably alleviate the UVB-induced damages to cells and reversed the UVB-caused biomarker changes to a great extent, which was comparable to the effects of administration of NF-κB inhibitor PDTC, suggesting the inhibition of nuclear translocation and DNA-binding activity of NF-κB. Furthermore, Klotho overexpression was proved to decrease the nuclear expression of NF-κB as much as the treatment with PDTC, which provides support for the direct regulation of NF-κB by Klotho.

Conclusions

Collectively, our work provides new insight into the potential role of Klotho in the context of UVB-induced injuries in human keratinocytes, as well as providing the basis for future study of new therapies against UV-related skin disease.

Resveratrol: from diet to topical usage

The stilbene derivative resveratrol (3,5,4'-trihydroxy-stilbene; RESV) has become the subject of interest of many researchers and the pharmaceutical industries due to its well-acclaimed beneficial biological activities. Although earlier research tended to focus on the effects of RESV on cardiovascular disorders, many other studies have described the beneficial effects of RESV in the areas of cancer chemoprevention and inflammation and interest of researchers on this compound is still increasing. It is now well accepted that the effect of RESV is not just due to its so called "antioxidant" activity but mainly (if not only) because of the ability of this compound to trigger cell signaling pathways and gene expression involved in cellular defense systems. Many "in vitro" studies on RESV did not take into account that although its oral absorption is about 75% it undergoes rapid metabolism and the concentration in the blood stream is almost undetectable. For this reason interest in the topical usage of RESV by cosmeceutical skin care brands has exponentially increased in the last decade reporting in general very promising results on its beneficial effect in protecting the skin from outdoor insults, but there is still some controversy on its topical usage mainly surrounding the concentration used. Therefore, more basic research on the topical application of RESV should be performed to better understand the way it prevents cutaneous damage and whether it could be recommended as a preventive skin aging agent for all skin insults.

Aging and Parkinson's Disease: Inflammaging, neuroinflammation and biological remodeling as key factors in pathogenesis

In order to better understand the pathogenesis of Parkinson's Disease (PD) it is important to consider possible contributory factors inherent to the aging process, as age-related changes in a number of physiological systems (perhaps incurred within particular environments) appear to influence the onset and progression of neurodegenerative disorders. Accordingly, we posit that a principal mechanism underlying PD is inflammaging, i.e. the chronic inflammatory process characterized by an imbalance of pro- and anti-inflammatory mechanisms which has been recognized as operative in several age-related, and notably neurodegenerative diseases. Recent conceptualization suggests that inflammaging is part of the complex adaptive mechanisms ("re-modeling") that are ongoing through the lifespan, and which function to prevent or mitigate endogenous processes of tissue disruption and degenerative change(s). The absence of an adequate anti-inflammatory response can fuel inflammaging, which propagates on both local (i.e.- from cell to cell) and systemic levels (e.g.- via exosomes and other molecules present in the blood). In general, this scenario is compatible with the hypothesis that inflammaging represents a hormetic or hormetic-like effect, in which low levels of inflammatory stress may prompt induction of anti-inflammatory mediators and mechanisms, while sustained pro-inflammatory stress incurs higher and more durable levels of inflammatory substances, which, in turn prompt a local-to-systemic effect and more diverse inflammatory response(s). Given this perspective, new treatments of PD may be envisioned that strategically are aimed at exerting hormetic effects to sustain anti-inflammatory responses, inclusive perhaps, of modulating the inflammatory influence of the gut microbiota.

The signaling involved in autophagy machinery in keratinocytes and therapeutic approaches for skin diseases

Autophagy is responsible for the lysosomal degradation of proteins, organelles, microorganisms and exogenous particles. Epidermis primarily consists of keratinocytes which functions as an extremely important barrier. Investigation on autophagy in keratinocytes has been continuously renewing, but is not so systematic due to the complexity of the autophagy machinery. Here we reviewed recent studies on the autophagy in keratinocyte with a focus on interplay between autophagy machinery and keratinocytes biology, and novel autophagy regulators identified in keratinocytes. In this review, we discussed the roles of autophagy in apoptosis, differentiation, immune response, survival and melanin metabolism, trying to reveal the possible involvement of autophagy in skin aging, skin disorders and skin color formation. Since autophagy routinely plays a double-edged sword role in various conditions, its functions in skin homeostasis and potential application as a therapeutic target for skin diseases remains to be clarified. Furthermore, more investigations are needed on optimizing designed strategies to inhibit or enhance autophagy for clinical efficacy.

Testing of resveratrol microemulsion photostability and protective effect against UV induced oxidative stress

Resveratrol is well known for its antioxidant activity and susceptibility to ultraviolet radiation. Development of formulations providing improved stability and relevant drug delivery of resveratrol is still a challenging task. The aim of this study was to determine protective characteristics of formulated microemulsions by evaluating photoisomerization of resveratrol and to investigate the effects of resveratrol on human keratinocyte cells under oxidative stress caused by ultraviolet radiation. Incorporation of resveratrol into microemulsions resulted in increased photostability of active compounds and the results demonstrated that photodegradation of resveratrol was significantly delayed. Results of biopharmaceutical evaluation in vitro demonstrated that up to 60 % of resveratrol was released from microemulsions within 6 hours under a constant release rate profile. In vivo biological testing confirmed the ability of resveratrol to protect cells from oxidative stress and to increase cell viability. It was concluded that microemulsions might be considered in the development of UV light sensitive compounds.

Role of keratin 24 in human epidermal keratinocytes

Keratin 24 (K24) is a new kind of keratin genes, which encodes a novel keratin protein, K24 that bears high similarity to the type I keratins and displays a unique expression profile. However, the role of K24 is incompletely understood. In our study, we investigated the localization of K24 within the epidermis and possible functions. Keratin 24 was found to be modestly overexpressed in senescent keratinocytes and was mainly restricted to the upper stratum spinosum of epidermis. The protein was required for terminal differentiation upon CaCl2-induced differentiation. In vitro results showed that increased K24 in keratinocytes dramatically changed the differentiation of primary keratinocytes. It also inhibited cell survival by G1/S phase cell cycle arrest and induced senescence, autophagy and apoptosis of keratinocytes. In addition, K24 activated PKCδ signal pathway involving in cellular survival. In summary, K24 may be suggested as a potential differentiation marker and anti-proliferative factor in the epidermis.

The Roles of Autophagy and the Inflammasome during Environmental Stress-Triggered Skin Inflammation

Inflammatory skin diseases are the most common problem in dermatology. The induction of skin inflammation by environmental stressors such as ultraviolet radiation (UVR), hexavalent chromium (Cr(VI)) and TiO₂/ZnO/Ag nanoparticles (NPs) has been demonstrated previously. Recent studies have indicated that the inflammasome is often wrongly activated by these environmental irritants, thus inducing massive inflammation and resulting in the development of inflammatory diseases. The regulation of the inflammasome with respect to skin inflammation is complex and is still not completely understood. Autophagy, an intracellular degradation system that is associated with the maintenance of cellular homeostasis, plays a key role in inflammasome inactivation. As a housekeeping pathway, cells utilize autophagy to maintain the homeostasis of the organ structure and function when exposed to environmental stressors. However, only a few studies have examined the effect of autophagy and/or the inflammasome on skin pathogenesis. Here we review recent findings regarding the involvement of autophagy and inflammasome activation during skin inflammation. We posit that autophagy induction is a novel mechanism inter-modulating environmental stressor-induced skin inflammation. We also attempt to highlight the role of the inflammasome and the possible underlying mechanisms and pathways reflecting the pathogenesis of skin inflammation induced by UVR, Cr(VI) and TiO₂/ZnO/Ag NPs. A more profound understanding about the crosstalk between autophagy and the inflammasome will contribute to the development of prevention and intervention strategies against human skin disease.

Dihydroceramide desaturase inhibitors induce autophagy via dihydroceramide-dependent and independent mechanisms

BACKGROUND

Autophagy consists on the delivery of cytoplasmic material and organelles to lysosomes for degradation. Research on autophagy is a growing field because deciphering the basic mechanisms of autophagy is key to understanding its role in health and disease, and to paving the way to discovering novel therapeutic strategies. Studies with chemotherapeutic drugs and pharmacological tools support a role for dihydroceramides as mediators of autophagy. However, their effect on the autophagy outcome (cell survival or death) is more controversial.

METHODS

We have examined the capacity of structurally varied Des1 inhibitors to stimulate autophagy (LC3-II analysis), to increase dihydroceramides (mass spectrometry) and to reduce cell viability (SRB) in T98G and U87MG glioblastoma cells under different experimental conditions.

RESULTS

The compounds activity on autophagy induction took place concomitantly with accumulation of dihydroceramides, which occurred by both stimulation of ceramide synthesis de novo and reduction of Des1 activity. However, autophagy was also induced by the test compounds after preincubation with myriocin and in cells with a reduced capacity to produce dihydroceramides (U87DND). Autophagy inhibition with 3-methyladenine in the de novo dihydroceramide synthesis competent U87MG cells increased cytotoxicity, while genetic inhibition of autophagy in U87DND cells, poorly efficient at synthesizing dihydroceramides, augmented resistance to the test compounds.

CONCLUSION

Dihydroceramide desaturase 1 inhibitors activate autophagy via both dihydroceramide-dependent and independent pathways and the balance between the two pathways influences the final cell fate.

GENERAL SIGNIFICANCE

The cells capacity to biosynthesize dihydroceramides must be taken into account in proautophagic Des1 inhibitors-including therapies.

Convergent Effects of Resveratrol and PYK2 on Prostate Cells

Resveratrol, a dietary polyphenol, is under consideration as chemopreventive and chemotherapeutic agent for several diseases, including cancer. However, its mechanisms of action and its effects on non-tumor cells, fundamental to understand its real efficacy as chemopreventive agent, remain largely unknown. Proline-rich tyrosine kinase 2 (PYK2), a non-receptor tyrosine kinase acting as signaling mediator of different stimuli, behaves as tumor-suppressor in prostate. Since, PYK2 and RSV share several fields of interaction, including oxidative stress, we have investigated their functional relationship in human non-transformed prostate EPN cells and in their tumor-prone counterpart EPN-PKM, expressing a PYK2 dead-kinase mutant. We show that RSV has a strong biological activity in both cell lines, decreasing ROS production, inducing morphological changes and reversible growth arrest, and activating autophagy but not apoptosis. Interestingly, the PYK2 mutant increases basal ROS and autophagy levels, and modulates the intensity of RSV effects. In particular, the anti-oxidant effect of RSV is more potent in EPN than in EPN-PKM, whereas its anti-proliferative and pro-autophagic effects are more significant in EPN-PKM. Consistently, PYK2 depletion by RNAi replicates the effects of the PKM mutant. Taken together, our results reveal that PYK2 and RSV act on common cellular pathways and suggest that RSV effects on prostate cells may depend on mutational-state or expression levels of PYK2 that emerges as a possible mediator of RSV mechanisms of action. Moreover, the observation that resveratrol effects are reversible and not associated to apoptosis in tumor-prone EPN-PKM cells suggests caution for its use in humans.

Inhibition of Autophagy Enhances Curcumin United light irradiation-induced Oxidative Stress and Tumor Growth Suppression in Human Melanoma Cells

Malignant melanoma is the most aggressive form of skin carcinoma, which possesses fast propagating and highly invasive characteristics. Curcumin is a natural phenol compound that has various biological activities, such as anti-proliferative and apoptosis-accelerating impacts on tumor cells. Unfortunately, the therapeutical activities of Cur are severely hindered due to its extremely low bioavailability. In this study, a cooperative therapy of low concentration Cur combined with red united blue light irradiation was performed to inspect the synergistic effects on the apoptosis, proliferation and autophagy in human melanoma A375 cell. The results showed that red united blue light irradiation efficaciously synergized with Cur to trigger oxidative stress-mediated cell death, induce apoptosis and inhibit cell proliferation. Meanwhile, Western blotting revealed that combined disposure induced the formation of autophagosomes. Conversely, inhibition of the autophagy enhanced apoptosis, obstructed cell cycle arrest and induced reversible proliferation arrest to senescence. These findings suggest that Cur combined with red united blue light irradiation could generate photochemo-preventive effects via enhancing apoptosis and triggering autophagy, and pharmacological inhibition of autophagy convert reversible arrested cells to senescence, therefore reducing the possibility that damaged cells might escape programmed death.

Polydatin post-treatment alleviates myocardial ischaemia/reperfusion injury by promoting autophagic flux

The present paper provides evidence that polydatin (PD) post-treatment alleviates myocardial ischaemia/reperfusion (I/R) injury by promoting autophagic flux to clear damaged mitochondria to reduce reactive oxygen species (ROS) and cell death.

Use of Polyphenolic Compounds in Dermatologic Oncology

Polyphenols are a widely used class of compounds in dermatology. While phenol itself, the most basic member of the phenol family, is chemically synthesized, most polyphenolic compounds are found in plants and form part of their defense mechanism against decomposition. Polyphenolic compounds, which include phenolic acids, flavonoids, stilbenes, and lignans, play an integral role in preventing the attack on plants by bacteria and fungi, as well as serving as cross-links in plant polymers. There is also mounting evidence that polyphenolic compounds play an important role in human health as well. One of the most important benefits, which puts them in the spotlight of current studies, is their antitumor profile. Some of these polyphenolic compounds have already presented promising results in either in vitro or in vivo studies for non-melanoma skin cancer and melanoma. These compounds act on several biomolecular pathways including cell division cycle arrest, autophagy, and apoptosis. Indeed, such natural compounds may be of potential for both preventive and therapeutic fields of cancer. This review evaluates the existing scientific literature in order to provide support for new research opportunities using polyphenolic compounds in oncodermatology.

The photoprotective effects of 2-benzoyl-3-phenylquinoxaline 1,4-dioxide against UVB-induced damage in HaCaT cells

With the increasing levels of atmospheric ozone depletion, there has been much concern about the causal effects of high levels of ultraviolet radiation reaching the Earth's surface on skin cancer. This has led to growing interest in identifying new active ingredients for use in commercial sunscreens. In our study, the chemical compound 2-benzoyl-3-phenylquinoxaline 1,4-dioxide (BPQ) prepared by the Beirut reaction was tested for its ability to protect a human keratinocyte cell line (HaCaT) against ultraviolet B radiation (280-315 nm). We show that BPQ exhibited strong absorbance in the UVB range, with an overall absorption spectrum very similar to that of Padimate-O, a well-known active ingredient used in commercial sunscreens. HaCaT cells, which were irradiated with UVB in the presence of multiple doses of BPQ, exhibited, in a dose-dependent fashion, a significantly higher viability and lower oxidative stress levels than cells irradiated in the absence of drug. Our results show that BPQ is a potential photoprotective drug that holds great promise for use as an active ingredient in commercial sunscreens.

Trehalose, sucrose and raffinose are novel activators of autophagy in human keratinocytes through an mTOR-independent pathway

Trehalose is a natural disaccharide that is found in a diverse range of organisms but not in mammals. Autophagy is a process which mediates the sequestration, lysosomal delivery and degradation of proteins and organelles. Studies have shown that trehalose exerts beneficial effects through inducing autophagy in mammalian cells. However, whether trehalose or other saccharides can activate autophagy in keratinocytes is unknown. Here, we found that trehalose treatment increased the LC3-I to LC3-II conversion, acridine orange-stained vacuoles and GFP-LC3B (LC3B protein tagged with green fluorescent protein) puncta in the HaCaT human keratinocyte cell line, indicating autophagy induction. Trehalose-induced autophagy was also observed in primary keratinocytes and the A431 epidermal cancer cell line. mTOR signalling was not affected by trehalose treatment, suggesting that trehalose induced autophagy through an mTOR-independent pathway. mTOR-independent autophagy induction was also observed in HaCaT and HeLa cells treated with sucrose or raffinose but not in glucose, maltose or sorbitol treated HaCaT cells, indicating that autophagy induction was not a general property of saccharides. Finally, although trehalose treatment had an inhibitory effect on cell proliferation, it had a cytoprotective effect on cells exposed to UVB radiation. Our study provides new insight into the saccharide-mediated regulation of autophagy in keratinocytes.

A SIRT3/AMPK/autophagy network orchestrates the protective effects of trans-resveratrol in stressed peritoneal macrophages and RAW 264.7 macrophages

Resveratrol gains a great interest for its strong antioxidant properties, while the molecular mechanisms underlie the beneficial effects on psychosocial stress remain controversial. In this study, we demonstrated that resveratrol protected peritoneal macrophages and RAW 264.7 cells from stress-induced decrease in the total cell count, phagocytic capability, reactive oxygen species generation, monodansylcadaverine and mitochondrial membrane potential in stressed mice. Resveratrol promoted stress-induced autophagy in both models. Modulation of autophagy by rapamycin or 3-methyladenine regulated the protective effect of resveratrol, suggesting a role of autophagy in the protective mechanisms of resveratrol. The comparison studies revealed that distinct mechanisms were implicated in the protective effect of resveratrol and other antioxidants (vitamin C and edaravone). Resveratrol promoted autophagy via upregulating SIRT3 expression and phosphorylation of AMP-activated protein kinase (AMPK). Knockdown of SIRT3 resulted in decreased autophagy and abolished protective effect of resveratrol. SIRT1 was also involved in the protective mechanism of resveratrol, although its effect on autophagy was unnoticeable. Pharmacological manipulation of autophagy modulated the effects of resveratrol on SIRT3 and AMPK, revealing the engagement of a positive feedback loop. In sharp contrast, vitamin C and edaravone effectively protected macrophages from stress-induced cytotoxicity, accompanied by downregulated SIRT3 expression and AMPK phosphorylation, and decreased level of autophagy response. Taken together, we conclude that a SIRT3/AMPK/autophagy network orchestrates in the protective effect of resveratrol in macrophages.

Coffee Silverskin Extract Protects against Accelerated Aging Caused by Oxidative Agents

Nowadays, coffee beans are almost exclusively used for the preparation of the beverage. The sustainability of coffee production can be achieved introducing new applications for the valorization of coffee by-products. Coffee silverskin is the by-product generated during roasting, and because of its powerful antioxidant capacity, coffee silverskin aqueous extract (CSE) may be used for other applications, such as antiaging cosmetics and dermaceutics. This study aims to contribute to the coffee sector’s sustainability through the application of CSE to preserve skin health. Preclinical data regarding the antiaging properties of CSE employing human keratinocytes and Caenorhabditis elegans are collected during the present study. Accelerated aging was induced by tert-butyl hydroperoxide (t-BOOH) in HaCaT cells and by ultraviolet radiation C (UVC) in C. elegans. Results suggest that the tested concentrations of coffee extracts were not cytotoxic, and CSE 1 mg/mL gave resistance to skin cells when oxidative damage was induced by t-BOOH. On the other hand, nematodes treated with CSE (1 mg/mL) showed a significant increased longevity compared to those cultured on a standard diet. In conclusion, our results support the antiaging properties of the CSE and its great potential for improving skin health due to its antioxidant character associated with phenols among other bioactive compounds present in the botanical material.

Resveratrol induces human keratinocyte damage via the activation of class III histone deacetylase, Sirt1

Human skin diseases are various and induce chronic inflammatory disorders, including psoriasis, atopic dermatitis and certain forms of ichthyosis. Psoriasis is a chronic inflammatory skin disease characterized by circumscribed, red, thickened plaques. Regulation of the balance between growth, differentiation and death is critical to keratinocytes; when altered, epidermal keratinocytes undergo hyperproliferation, abnormal differentiation and inflammatory infiltration. In the present study, we focused on the effects of resveratrol, found in red wine and peanuts, on the cell death of keratinocytes. We additionally studied the mechanism of resveratrol on Sirt1, a class III histone deacetylase, and Akt phosphorylation. Resveratrol caused apoptosis and increased Sirt1 expression in human HaCaT keratinocytes, following a decrease in the p62 protein level. Inhibition of Sirt1 by Sirt1 inhibitor restored cell viability and protein levels. Furthermore, we showed that resveratrol-induced Sirt1 blocked Akt phosphorylation. The present results indicated that resveratrol inhibited the Akt pathways by inducing Sirt1, thus leading to cell death. These data suggest that resveratrol-mediated activation of Sirt1 histone deacetylase may be a potential therapeutic target for skin diseases including psoriasis.

Tyrosol prevents apoptosis in irradiated keratinocytes

BACKGROUND

Phenolic compounds, the biggest group of natural antioxidants, have attracted much attention due to their known and wide-ranging biological activities, as well as to their health effects. In particular, regardless their antioxidant activity, they play a key role in the control of several inflammation-associated processes as well as in improving antioxidant defense system. In an our previous work we have demonstrated the ability of Hydroxytyrosol, an ortho-diphenolic compound, essential component of oleuropein, in preventing apoptotic cell death induced by UVB radiation in HaCaT cell lines in vitro. In olive oil, besides Hydroxytyrosol, there are appreciable amounts of Tyrosol and its secoiridoid derivatives.

OBJECTIVE

It has been well established that Tyrosol has a significantly lower antioxidant activity than Hydroxytyrosol, but despite this, recent studies suggest that Tyrosol exerts a powerful protective effect against oxidative injuries in cell systems and that it is able to improve the intracellular antioxidant defenses.

MATERIALS AND METHODS

Here, Tyrosol effect has been evaluated in HaCaT cells exposed to UVB radiation by means of morphological and molecular analyses.

RESULTS

Our study revealed the polyphenol ability in reducing apoptotic markers and in protecting HaCaT cells from damage.

CONCLUSION

These findings suggest an important role of Tyrosol in protecting cells from apoptotic cell death and encourage the use of this phytochemical as biological ingredient in topical preparations as possible tool to prevent skin damage.

Anti-tumor properties of cis-resveratrol methylated analogs in metastatic mouse melanoma cells

Resveratrol (E-3,5,4'-trihydroxystilbene) is a polyphenol found in red wine that has been shown to have multiple anti-cancer properties. Although cis-(Z)- and trans-(E)-isomers of resveratrol occur in nature, the cis form is not biologically active. However, methylation at key positions of the cis form results in more potent anti-cancer properties. This study determined that synthetic cis-polymethoxystilbenes (methylated analogs of cis-resveratrol) inhibited cancer-related phenotypes of metastatic B16 F10 and non-metastatic B16 F1 mouse melanoma cells. In contrast with cis- or trans-resveratrol and trans-polymethoxystilbene which were ineffective at 10 μM, cis-polymethoxystilbenes inhibited motility and proliferation of melanoma cells with low micromolar specificity (IC50 < 10 μM). Inhibitory effects by cis-polymethoxystilbenes were significantly stronger with B16 F10 cells and were accompanied by decreased expression of β-tubulin and pleckstrin homology domain-interacting protein, a marker of metastatic B16 cells. Thus, cis-polymethoxystilbenes have potential as chemotherapeutic agents for metastatic melanoma.

Diet in dermatology: Part II. Melanoma, chronic urticaria, and psoriasis

The roles of dietary factors in aggravating, preventing, or treating skin diseases are common questions encountered in dermatology practice. Part II of this two-part series reviews dietary modifications that can potentially be utilized in the management of melanoma, chronic urticaria, and psoriasis patients. Specifically, we examine the effect of alcohol consumption and supplementation with vitamins D and E, polyunsaturated fatty acids, selenium, green tea, resveratrol, and lycopene on melanoma risk. The relationships between chronic urticaria symptoms and dietary pseudoallergens, gluten, and vitamin D are analyzed. We explore weight loss, reduced alcohol consumption, and gluten avoidance as means of reducing psoriasis-associated morbidity, as well as the possible utility of supplementation with polyunsaturated fatty acids, folic acid, vitamin D, and antioxidants. With proper knowledge of the role of diet in these cutaneous disease processes, dermatologists can better answer patient inquiries and consider implementation of dietary modifications as adjuncts to other treatments and preventative measures.

Modulation of viability and apoptosis of UVB-exposed human keratinocyte HaCaT cells by aqueous methanol extract of laver (Porphyra yezoensis)

We investigated the effect of 80% methanol extract of laver (Porphyra yezoensis) on the UVB-exposed HaCaT cells, human keratinocytes. The laver extract showed absorbance spectrum characteristic of porphyra-334 or shinorine, major mycosporine-like amino acids (MAAs) in red algae, and contained phenolic compounds. UVB exposure decreased cell viability and increased apoptotic cell fractions, and it also decreased the ratio of reduced (GSH) to oxidized glutathione (GSSG) and the total glutathione content. Post-treatment with the laver extract significantly increased the net viability and also the apoptotic cell fractions of UVB-exposed cells. The extract caused increase in GSH/GSSG ratio, yet it exacerbated the decrease in glutathione content in the UVB-exposed cells. These effects of the laver extract were also manifested in the sham-exposed cells, suggesting that those effects might be general phenomena caused by the laver extract. The extract treatment enhanced the UVB-induced phosphorylation of JNK and ERK, affecting more the latter. Our results suggest that the post-treatment with laver extract may protect UVB-exposed skin cells not only by increasing overall cell proliferation but also by enhancing apoptosis of damaged cells, via activating JNK and ERK signaling pathways, in which modulation of the content and redox status of glutathione may take significant parts.

Antioxidants in the prevention of UVB-induced keratynocyte apoptosis

Skin cells can respond to UVB-induced damage by counteracting it through antioxidant activation and DNA repair mechanisms or, when damage is massive by undergoing programmed cell death. Antioxidant factors, and, in particular, food compounds, have attracted much interest because of their potential use in new protective strategies for degenerative skin disorders. Melatonin, creatine and hydroxytyrosol show a variety of pharmacological and clinical benefits including anti-oxidant and anti-inflammatory activities. Here, the potential protective actions of antioxidant compounds against UVB-induced apoptosis were investigated in human keratinocytes. The cells were pre-treated with antioxidants before UVB exposure and their effect evaluated by means of ultrastructural and molecular analyses. After UVB radiation typical morphological apoptotic features and in situ DNA fragmentation after TUNEL reaction, appeared. A significant numerical decrease of apoptotic patterns could be observed when antioxidants were administrated before cell death induction. Moreover, both the intrinsic and extrinsic apoptotic pathways appeared activated after UVB radiation, and their down-regulation has been shown when antioxidants were added to cells before death induction. In conclusion, these compounds are able to prevent apoptotic cell death in human keratinocytes exposed to UVB, suggesting, for these molecules, an important role in preventing skin damage.