Silencing Stem Cell Factor Gene in Fibroblasts to Regulate Paracrine Factor Productions and Enhance c-Kit Expression in Melanocytes on Melanogenesis

What lies behind melasma: a review of the related skin microenvironment

Melasma is an acquired chronic pigmentary disorder affecting millions of individuals worldwide. However, the pathogenesis of melasma remains unclear. This article provides a comprehensive review of the pathophysiological changes occurring in the skin microenvironment of melasma lesions, which can be summarized as follows: (1) skin barrier dysfunction and abnormal synthesis, transport, and intracellular distribution of melanin in the epidermis; (2) basement membrane damage; (3) solar elastosis, vascular changes, senescent fibroblasts, mast cell infiltration, and sebocyte participation in the dermis; and (4) systemic factors such as sex hormones and oxidative stress. Furthermore, potential therapeutic strategies are introduced to provide novel perspectives for fundamental and clinical research related to melasma.

Differentiation of cultured hair follicle neural crest stem cells into functional melanocytes

Many autologous melanocytes are required for surgical treatment of depigmentation diseases such as vitiligo. However, primary cultured melanocytes have a limited number of in vitro passages. The production of functional epidermal melanocytes from stem cells provides an unprecedented source of cell therapy for vitiligo. This study explores the clinical application of melanocytes induced by hair follicle neural crest stem cells (HFNCSCs). This study established an in vitro differentiation model of HFNCSCs into melanocytes. Results demonstrate that most differentiated melanocytes expressed the proteins C-KIT, MITF, S-100B, TYRP1, TYRP2, and tyrosinase. The HFNCSC-derived melanocytes were successfully transplanted onto the dorsal skin of mice and survived in the local tissues, expressing marker protein of melanocytes. In conclusion, HFNCSCs in mice can be induced to differentiate into melanocytes under specific conditions. These induced melanocytes exhibit the potential to facilitate repigmentation in the lesion areas of vitiligo-affected mice, suggesting a promising avenue for therapeutic intervention.

Emerging Role of Fibroblasts in Vitiligo: A Formerly Underestimated Rising Star

Vitiligo is a disfiguring depigmentation disorder characterized by loss of melanocytes. Although numerous studies have been conducted on the pathogenesis of vitiligo, the underlying mechanisms remain unclear. Although most studies have focused on melanocytes and keratinocytes, growing evidence suggests the involvement of dermal fibroblasts, residing deeper in the skin. This review aims to elucidate the role of fibroblasts in both the physiological regulation of skin pigmentation and their pathological contribution to depigmentation, with the goal of shedding light on the involvement of fibroblasts in vitiligo. The topics covered in this review include alterations in the secretome, premature senescence, autophagy dysfunction, abnormal extracellular matrix, autoimmunity, and metabolic changes.

A Comprehensive Review of Non-Surgical Treatments for Hypertrophic and Keloid Scars in Skin of Color

Hypertrophic and keloid scars are fibroproliferative growths resulting from aberrant wound healing. Individuals with Fitzpatrick skin types (FSTs) IV-VI are particularly predisposed to hypertrophic and keloid scarring, yet specific guidelines for these populations are still lacking within the literature. Therefore, this comprehensive review provides a list of various treatments and considerations for hypertrophic and keloid scarring in patients with skin of color. We constructed a comprehensive PubMed search term and performed quadruple-blinded screening on all resulting studies to achieve this objective. Our findings demonstrate 1) the lack of efficacious treatments for raised scars within this population and 2) the need to empirically investigate individualized and multimodal therapeutic options for those with skin of color.

The Skin-Brain Axis: From UV and Pigmentation to Behaviour Modulation

The skin-brain axis has been suggested to play a role in several pathophysiological conditions, including opioid addiction, Parkinson's disease and many others. Recent evidence suggests that pathways regulating skin pigmentation may directly and indirectly regulate behaviour. Conversely, CNS-driven neural and hormonal responses have been demonstrated to regulate pigmentation, e.g., under stress. Additionally, due to the shared neuroectodermal origins of the melanocytes and neurons in the CNS, certain CNS diseases may be linked to pigmentation-related changes due to common regulators, e.g., MC1R variations. Furthermore, the HPA analogue of the skin connects skin pigmentation to the endocrine system, thereby allowing the skin to index possible hormonal abnormalities visibly. In this review, insight is provided into skin pigment production and neuromelanin synthesis in the brain and recent findings are summarised on how signalling pathways in the skin, with a particular focus on pigmentation, are interconnected with the central nervous system. Thus, this review may supply a better understanding of the mechanism of several skin-brain associations in health and disease.

Cyclic AMP-regulatory element-binding protein: a novel UV-targeted transcription factor in skin cancer

Common therapeutics in relation to melanoma and non-melanoma cancers include the use of kinase inhibitors. The long-term benefits of kinases, however, are limited by development of drug resistance. An alternative approach for treatment would be to focus on transcription factors. Cyclic AMP-regulatory element-binding protein (CREB) is a transcription factor that is commonly overactivated or overexpressed in many different cancers including skin cancer. Ultraviolet radiation (UVR), one of the main causes of skin cancer, can activate CREB in both melanocytes and keratinocytes. In addition, CREB has been found to be activated in skin cancers. Considering the prominent role that CREB plays in skin cancers, the studies reviewed herein raise the possibility of CREB as a potential prognostic and diagnostic marker of skin cancer and a novel target for therapeutic intervention.

Comparative Analysis of Olive-Derived Phenolic Compounds' Pro-Melanogenesis Effects on B16F10 Cells and Epidermal Human Melanocytes

Olive leaf contains plenty of phenolic compounds, among which oleuropein (OP) is the main component and belongs to the group of secoiridoids. Additionally, phenolic compounds such as oleocanthal (OL) and oleacein (OC), which share a structural similarity with OP and two aldehyde groups, are also present in olive leaves. These compounds have been studied for several health benefits, such as anti-cancer and antioxidant effects. However, their impact on the skin remains unknown. Therefore, this study aims to compare the effects of these three compounds on melanogenesis using B16F10 cells and human epidermal cells. Thousands of gene expressions were measured by global gene expression profiling with B16F10 cells. We found that glutaraldehyde compounds derived from olive leaves have a potential effect on the activation of the melanogenesis pathway and inducing differentiation in B16F10 cells. Accordingly, the pro-melanogenesis effect was investigated by means of melanin quantification, mRNA, and protein expression using human epidermal melanocytes (HEM). This study suggests that secoiridoid and its derivates have an impact on skin protection by promoting melanin production in both human and mouse cell lines.

Inhibition of α-melanocyte-stimulating hormone-induced melanogenesis and molecular mechanisms by polyphenol-enriched fraction of Tagetes erecta L. flower

BACKGROUND

The pursuit for safe and efficacious skin-whitening agents has prompted a dedicated exploration of plant-derived compounds. Notably, Tagetes erecta L. flowers have been used as a medicinal extract and possessed in vitro mushroom tyrosinase activity. However, whether polyphenol-enriched fraction extracted from T. erecta L. flowers (TE) regulates melanogenesis within cellular and animal models has not yet been investigated.

PURPOSE

This study aimed to investigate the effect of TE as a prospective inhibitor of melanogenesis.

METHODS

Through advanced UPLC-QTof/MS analysis, the components of TE were analyzed. Anti-melanogenic effects of TE were evaluated in α-melanocyte-stimulating hormone (α-MSH)-stimulated B16F10 melanoma cells by measuring cell viability assay, extracellular and intracellular melanin biosynthesis, cyclic adenosine monophosphate (cAMP) production, and melanogenesis-related gene and protein expression. Zebrafish larvae were employed for in vivo studies, assessing both heart rate and melanogenesis. Furthermore, molecular docking analyses were employed to predict the interaction between TE components and the melanocortin 1 receptor (MC1R). Direct binding activity of TE components to MC1R was compared with [Nle4, d-Phe7]-MSH (NDP-MSH).

RESULTS

TE was found to contain significant phenolic compounds such as patulitrin, quercetagetin, kaempferol, patuletin, and isorhamnetin. This study revealed that TE effectively inhibits melanin biosynthesis in both in vitro and in vivo models. This inhibition was attributed to interference of TE with the cAMP-cAMP response element-binding protein (CREB)-microphthalmia-associated transcription factor (MITF)-tyrosinase pathway, which plays a pivotal role in regulating melanogenesis. Importantly, TE exhibited the remarkable ability to curtail α-MSH-induced melanogenesis in zebrafish larvae without impacting heart rates. Molecular docking analyses predicted that the components of TE possibly interact with the melanocortin 1 receptor, suggesting their role as potential inhibitors of melanin biosynthesis. However, through the direct binding activity compared with NDP-MSH, any TE components did not directly bind to MC1R, suggesting that TE inhibits α-MSH-induced melanogenesis by inhibiting the cAMP-mediated intracellular signaling pathway. The assessment of anti-melanogenic activity, conducted both in vitro and in vivo, revealed that patulitrin and patuletin exhibited significant inhibitory effects on melanin formation, highlighting their potency as major contributors.

DISCUSSION

This investigation demonstrated the considerable potential of TE as a natural remedy endowed with remarkable anti-melanogenic properties. The demonstrated capacity of TE to attenuate melanin production by modulating the cAMP-CREB-MITF-tyrosinase pathway underscores its central role in management of disorders associated with excessive pigmentation. Importantly, the implications of these findings extend to the cosmetics industry, where TE emerges as a prospective and valuable ingredient for the formulation of skin-whitening products. The elucidated interactions between TE components and MC1R not only provide insight into a potential mechanism of action but also elevate the significance of this study. In summary, this study not only contributes to our comprehension of pigmentation-related conditions but also firmly establishes TE as a secure and natural strategy for the regulation of melanin production. The innovative aspects of TE propel it into the forefront of potential interventions, marking a noteworthy advancement in the pursuit of effective and safe solutions for pigmentation disorders.

Cell Therapy of Severe Ischemia in People with Diabetic Foot Ulcers-Do We Have Enough Evidence?

This current opinion article critically evaluates the efficacy of autologous cell therapy (ACT) for chronic limb-threatening ischemia (CLTI), especially in people with diabetes who are not candidates for standard revascularization. This treatment approach has been used in 'no-option' CLTI in the last two decades and more than 1700 patients have received ACT worldwide. Here we analyze the level of published evidence of ACT as well as our experience with this treatment method. Many studies have shown that ACT is safe and an effective method for patients with the most severe lower limb ischemia. However, some trials did not show any benefit of ACT, and there is some heterogeneity in the types of injected cells, route of administration and assessed endpoints. Nevertheless, we believe that ACT plays an important role in a comprehensive treatment of patients with diabetic foot and severe ischemia.

Definition of protocols for cryopreservation and three-dimensional in vitro culture of prepubertal goat testicular tissue after histomorphological, ultrastructural, and functional analysis

This study aims to define the best method (slow freezing or vitrification) and fragment size (1, 5, or 9 mm³) for prepubertal goat testis cryopreservation, as well as to evaluate testicular morphological integrity after cryopreservation and in vitro culture (IVC). Initially (experiment I), 1, 5, or 9 mm³ testis fragments were cryopreserved by slow freezing using a Mr. Frosty container with 20% Dimethylsulfoxide (DMSO) or vitrified using the Ovarian Tissue Cryosystem (OTC) device, (Equilibration solution - ES: 10% DMSO and 10% ethylene glycol - EG; Vitrification solution - VS: 20% DMSO and 20% EG) and then subjected to morphological analysis, type I and III collagen quantification and gene expression (Oct4, C-kit, Bax, and Bcl-2). Subsequently, (experiment II), fresh or cryopreserved by slow freezing testis fragments were cultured in vitro and submitted to morphological analysis by scanning electron microscopy. The data from the experiment I revealed fewer morphological alterations in 1 and 5 mm³ fragments after vitrification and slow freezing, respectively. The percentage of type I collagen fibers in 5 and 9 mm³ frozen was higher than in fresh or vitrified fragments. For type III collagen, fresh or frozen fragments of 1 and 5 mm3 showed a higher percentage than fragments of 9 mm3. Gene expression for Oct4 and C-kit after slow freezing or vitrification in the 5 mm3 fragments was lower than that observed in the fresh fragments. The Bax:Bcl-2 ratio in the 1 and 9 mm³ fragments was lower than in the 5 mm³ fragments for fresh fragments or after freezing. In experiment II, fragments cultured in vitro, previously frozen or not, showed more morphological alterations than fresh or frozen fragments. We concluded that slow freezing of 5 mm³ fragments was the best protocol for cryopreserving prepubertal goat testis and although the results of IVC are encouraging, it still needs improvement to restore testicular function after cryopreservation.

Fermented Aronia melanocarpa Inhibits Melanogenesis through Dual Mechanisms of the PI3K/AKT/GSK-3β and PKA/CREB Pathways

UV light causes excessive oxidative stress and abnormal melanin synthesis, which results in skin hyperpigmentation disorders such as freckles, sunspots, and age spots. Much research has been carried out to discover natural plants for ameliorating these disorders. Aronia melanocarpa contains various polyphenolic compounds with antioxidative activities, but its effects on melanogenesis have not been fully elucidated. In this study, we investigated the inhibitory effect of fermented Aronia melanocarpa (FA) fermented with Monascus purpureus on melanogenesis and its underlying mechanism in the B16F10 melanoma cell line. Our results indicate that FA inhibited tyrosinase activity and melanogenesis in alpha-melanocyte-stimulating hormone (α-MSH)-induced B16F10 cells. FA significantly downregulated the PKA/CREB pathway, resulting in decreased protein levels of tyrosinase, TRP-1, and MITF. FA also inhibited the transcription of MITF by increasing the phosphorylation levels of both GSK3β and AKT. Interestingly, we demonstrated that these results were owing to the significant increase in gallic acid, a phenolic compound of Aronia melanocarpa produced after the fermentation of Monascus purpureus. Taken together, our research suggests that Aronia melanocarpa fermented with Monascus purpureus acts as a melanin inhibitor and can be used as a potential cosmetic or therapeutic for improving hyperpigmentation disorders.

Anti-Inflammation and Anti-Melanogenic Effects of Maca Root Extracts Fermented Using Lactobacillus Strains

Maca is a well-known biennial herb with various physiological properties, such as antioxidant activity and immune response regulation. In this study, the antioxidant, anti-inflammatory, and anti-melanogenic effects of fermented maca root extracts were investigated. The fermentation was carried out using Lactobacillus strains, such as Lactiplantibacillus plantarum subsp. plantarum, Lacticaseibacillus rhamnosus, Lacticaseibacillus casei, and Lactobacillus gasseri. In RAW 264.7 cells, the non-fermented maca root extracts increased the secretion of nitric oxide (NO), an inflammatory mediator, in a dose-dependent manner. In contrast, the fermented extracts showed considerably lower NO secretion than the non-fermented extracts at concentrations of 5% and 10%. This indicates the effective anti-inflammatory effects of fermented maca. The fermented maca root extracts also inhibited tyrosinase activity, melanin synthesis, and melanogenesis by suppressing MITF-related mechanisms. These results show that fermented maca root extracts exhibit higher anti-inflammatory and anti-melanogenesis effects than non-fermented maca root extracts. Thus, maca root extracts fermented using Lactobacillus strains have the potential to be used as an effective cosmeceutical raw material.

A Comprehensive Review of Mammalian Pigmentation: Paving the Way for Innovative Hair Colour-Changing Cosmetics

The natural colour of hair shafts is formed at the bulb of hair follicles, and it is coupled to the hair growth cycle. Three critical processes must happen for efficient pigmentation: (1) melanosome biogenesis in neural crest-derived melanocytes, (2) the biochemical synthesis of melanins (melanogenesis) inside melanosomes, and (3) the transfer of melanin granules to surrounding pre-cortical keratinocytes for their incorporation into nascent hair fibres. All these steps are under complex genetic control. The array of natural hair colour shades are ascribed to polymorphisms in several pigmentary genes. A myriad of factors acting via autocrine, paracrine, and endocrine mechanisms also contributes for hair colour diversity. Given the enormous social and cosmetic importance attributed to hair colour, hair dyeing is today a common practice. Nonetheless, the adverse effects of the long-term usage of such cosmetic procedures demand the development of new methods for colour change. In this context, case reports of hair lightening, darkening and repigmentation as a side-effect of the therapeutic usage of many drugs substantiate the possibility to tune hair colour by interfering with the biology of follicular pigmentary units. By scrutinizing mammalian pigmentation, this review pinpoints key targetable processes for the development of innovative cosmetics that can safely change the hair colour from the inside out.

Stem cell factor/mast cell/CCL2/monocyte/macrophage axis promotes Coxsackievirus B3 myocarditis and cardiac fibrosis by increasing Ly6Chigh monocyte influx and fibrogenic mediators production

Mast cells (MCs), central players in allergy and parasitic infections, play key roles in inflammation and fibrosis. Here, the impact of MCs on the progression of Coxsackievirus B3 (CVB3)-induced viral myocarditis (VMC) and fibrosis was investigated using MC-deficient Kit^W-sh mice. Viral titres, cellular infiltrates and heart pathologies were evaluated and compared with wild-type (WT) mice during acute CVB3 infection of C57BL/6 mice. CVB3 infection induced an increased accumulation and degranulation of MCs in the hearts of mice during acute infection. MC-deficient Kit^W-sh mice had slightly higher viral titres, decreased VMC and cardiac fibrosis and improved cardiac dysfunction compared to WT mice via decreasing cardiac influx of Ly6C^high monocytes/macrophages (Mo/Mφ). While bone marrow-derived MC reconstitution decreased viral titre and worsened improved survival and VMC severity in Wsh mice. MC-fibroblasts co-culture revealed a cardiac MC-fibroblasts crosstalk during early infection: fibroblasts trigger MC degranulation and secretion of CCL2 and tumour necrosis factor alpha (TNF-α) via producing early stem cell factor (SCF); while MCs-fibrogenic mediators (TNF-α) stimulate fibroblasts to increase CCL2, α-smooth muscle actin (SMA), collagen and transforming growth factor beta（TGFβ) expression, thus aggravating cardiac fibrosis. MCs and fibroblast-derived CCL2s are both essential for cardiac Ly6C^high Mo/Mφ influx. Administration of recombinant mouse SCF to CVB3-infected mice aggravates VMC via accelerating MCs accumulation and cardiac influx of Ly6C^hi Mo/Mφ. Collectively, our data highlight an early MC-fibroblast crosstalk and SCF/MC/CCL2/Mo/Mφ axis as important mechanisms required for triggering VMC and myocardial fibrosis. This finding indicates critical roles of MCs in initiating and modulating cardiac innate response to CVB3 and has an implication in developing new and more effective treatments for VMC.

The Modulation of Melanogenesis in B16 Cells Upon Treatment with Plant Extracts and Isolated Plant Compounds

Plants are a rich source of secondary metabolites that exhibit numerous desired properties. The compounds may influence the biology of melanocytes, pigment cells that produce melanin, by modulating numerous signaling pathways, including cAMP/PKA, MAPKs and PI3K/AKT. Its downstream target is microphthalmia-associated transcription factor, responsible for the expression of the tyrosinase enzyme, which plays a major role in melanogenesis. Therefore, this literature review aims to provide insights related to melanogenesis modulation mechanisms of plant extracts and isolated plant compounds in B16 cells. Database searches were conducted using online-based library search instruments from 2012 to 2022, such as NCBI-PubMed and Google Scholar. Upregulation or downregulation of signaling pathways by phytochemicals can influence skin hypo- and hyperpigmentation by changing the level of melanin production, which may pose a significant cosmetic issue. Therefore, plant extracts or isolated plant compounds may be used in the therapy of pigmentation disorders.

The Function of Autophagy as a Regulator of Melanin Homeostasis

Melanosomes are melanocyte-specific organelles that protect cells from ultraviolet (UV)-induced deoxyribonucleic acid damage through the production and accumulation of melanin and are transferred from melanocytes to keratinocytes. The relatively well-known process by which melanin is synthesized from melanocytes is known as melanogenesis. The relationship between melanogenesis and autophagy is attracting the attention of researchers because proteins associated with autophagy, such as WD repeat domain phosphoinositide-interacting protein 1, microtubule-associated protein 1 light chain 3, autophagy-related (ATG)7, ATG4, beclin-1, and UV-radiation resistance-associated gene, contribute to the melanogenesis signaling pathway. Additionally, there are reports that some compounds used as whitening cosmetics materials induce skin depigmentation through autophagy. Thus, the possibility that autophagy is involved in the removal of melanin has been suggested. To date, however, there is a lack of data on melanosome autophagy and its underlying mechanism. This review highlights the importance of autophagy in melanin homeostasis by providing an overview of melanogenesis, autophagy, the autophagy machinery involved in melanogenesis, and natural compounds that induce autophagy-mediated depigmentation.

Dermal Pathology in Melasma: An Update Review

BACKGROUND

Melasma is a complex and multipathophysiological condition that is challenging to treat. The roles of each element in the dermis were highlighted in this recent year due to targeting it with emerging therapies. Although some studies have demonstrated abnormal findings in the dermis of melasma lesions, there are no integrated data regarding these findings.

PURPOSE

This article aims to discuss each finding in the dermis of melasma lesions and to provide some ideas about treatment options.

METHODS

An Internet search was completed using the MEDLINE, Embase, Scopus, and Google Scholar databases for relevant literature through June 2021 and reference lists of respective articles. Only the articles published in English language were included.

RESULTS

Several studies have focused on the dermal changes in melasma. Common findings included basement membrane disruption, pendulous melanocytes, marked solar elastosis, increased melanophages, increased mast cells, and neovascularization. In addition, each of them had the specified mechanism that may relate with the others.

CONCLUSION

Several changes in the dermis of melasma lesion may be connected with pathological changes in the epidermis. This may serve as a potential target treatment for melasma, which requires a multimodal approach.

Insights into the Pathogenesis of NF1-Associated Neoplasms

Neurofibromatosis type 1 (NF1) is one of the most common neurocutaneous genetic disorders, presenting with different cutaneous features such as café-au-lait macules, intertriginous skin freckling, and neurofibromas. Although most of the disease manifestations are benign, patients are at risk for a variety of malignancies, including malignant transformation of plexiform neurofibromas. Numerous studies have investigated the mechanisms by which these characteristic neurofibromas develop, with progress made toward unraveling the various players involved in their complex pathogenesis. In this review, we summarize the current understanding of the cells that give rise to NF1 neoplasms as well as the molecular mechanisms and cellular changes that confer tumorigenic potential. We also discuss the role of the tumor microenvironment and the key aspects of its various cell types that contribute to NF1-associated tumorigenesis. An increased understanding of these intrinsic and extrinsic components is critical for developing novel therapeutic approaches for affected patients.

Melanogenesis and Melasma Treatment

Melanocytes are highly specialised dendritic cells that transfer melanin to keratinocytes in subcellular lysosome-like organelles called melanosomes, where melanin is synthesised and stored. Melanin is a complex pigment that provides colour and photoprotection to the skin, hair, and eyes of mammals. The regulation of melanogenesis includes various mechanisms and factors including genetic, environmental, and endocrine factors. Knowledge of the pigmentation process is important not only to understand hyperpigmentation but also to design treatments and therapies to treat them. Whitening cosmetics with anti-melanogenesis activity are very popular. In the present manuscript, we review the mechanisms and the signalling pathways involved in skin pigmentation and we specifically focus on the alteration of melanogenesis that leads to melasma and results in hyperpigmentation. Finally, current therapies and treatments including topical, oral, and phototherapies are discussed and described, with a special emphasis on the cosmetics’ action.

Morin Induces Melanogenesis via Activation of MAPK Signaling Pathways in B16F10 Mouse Melanoma Cells

Morin is a well-known flavonoid, and has been reported to have various properties, such as anti-cell death, antioxidant, and anti-inflammatory properties. Although studies on the biochemical and biological actions of morin have been reported, the melanin biosynthesis effects and molecular mechanisms are unknown. In this study, we first found that morin has the effect of enhancing melanin biosynthesis in B16F10 mouse melanoma cells, and analyzed the molecular mechanism. In this study, we examined the effects of morin on the melanin contents and tyrosinase activity, as well as the protein expression levels of the melanogenic enzymes TRP-1, TRP-2, and microphtalmia-associated transcription factor (MITF) in B16F10 mouse melanoma cells. Morin showed no cytotoxicity in the concentration range of 5–100 μM, and significantly increased the intracellular tyrosinase activity and melanin contents. In mechanism analysis, morin increased the protein expression of TRP-1, TRP-2, and MITF associated with melanogenesis. Furthermore, morin increased phosphorylated ERK and p38 at the early time, and decreased phosphorylated ERK after 12 h. The results suggest that morin enhances melanin synthesis through the MAPK signaling pathways in B16F10 mouse melanoma cells.

Isokotomolide A from Cinnamomum kotoense Induce Melanoma Autophagy and Apoptosis In Vivo and In Vitro

Melanoma is an aggressive cancer with high lethality. In order to find new anticancer agents, isokotomolide A (Iso A) and secokotomolide A (Sec A) isolated from Cinnamomum kotoense were identified to be potential bioactive agents against human melanoma but without strong antioxidative properties. Cell proliferation assay displayed Iso A and Sec A treated in the normal human skin cells showed high viabilities. It also verified that two of them possess strong antimelanoma effect in concentration-dependent manners, especially on B16F10, A2058, MeWo, and A375 cells. Wound healing assay presented their excellent antimigratory effects. Through 3-N,3-N,6-N,6-N-Tetramethylacridine-3,6-diamine (acridine orange, AO) staining and Western blot, the autophagy induced by treatment was confirmed, including autophagy-related proteins (Atgs). By using annexin V–FITC/PI double-stain, the apoptosis was confirmed, and both components also triggered the cell cycle arrest and DNA damage. We demonstrated the correlations between the mitogen-activated protein kinase (MAPK) pathway and antimelanoma, such as caspase cascade activations. To further evaluate in vivo experiments, the inhibition of tumor cell growth was verified through the histopathological staining in a xenograft model. In this study, it was confirmed that Iso A and Sec A can encourage melanoma cell death via early autophagy and late apoptosis processes.

A Novel Oral Astaxanthin Nanoemulsion from Haematococcus pluvialis Induces Apoptosis in Lung Metastatic Melanoma

Astaxanthin (AST) is a naturally occurring xanthophyll carotenoid having the potential to be used as an anticancer agent; however, the human body has a low bioavailability of AST due to its poor solubility in the water phase. Therefore, we applied D-α-tocopheryl polyethylene glycol succinate (TPGS) as an emulsifier and natural edible peanut oil to form a steady oil-in-water (O/W) nanoemulsion loaded with AST (denoted as TAP-nanoemulsion). TAP-nanoemulsions were stable without the droplet coalescence against thermal treatments (30-90°C), pH value changes (over a range of 2.0-8.0), and ionic strength adjustments (at NaCl concentrations of 100-500 mM) measured by dynamic light scattering (DLS). AST within TAP-nanoemulsion was released up to 80% in a simulated intestinal enzymatic fluid in vitro, and the overall recovery rate was fairly consistent in the Caco-2 cellular model. In order to further evaluate in vivo melanoma inhibitory experiments, we injected the fluorescent-stained B16F10 cells into female C57BL/6 mouse tail veins and treated TAP-nanoemulsion in an oral gavage. qRT-PCR and Western blot demonstrated that TAP-nanoemulsion triggered effectively the apoptosis pathway, including enhancements of cleaved caspase-3 and caspase-9, ataxia-telangiectasia mutated kinase (ATM), and p21WAF1/CIP1 (p21) and decreases of B-cell lymphoma 2 (Bcl-2); cyclins D, D1, and E; mitogen-activated protein kinase (MEK); extracellular signal-regulated kinases (ERK); nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB); and matrix metallopeptidase-1 and metallopeptidase-9 (MMP-1 and MMP-9) in both gene and protein expressions. In conclusion, this study suggests that TAP-nanoemulsion with the oral treatment has a positive chemotherapy effect in melanoma with lung metastases in vivo. As far as we know, this is the first time to demonstrate that an antioxidant in nanoparticle administration cures lung metastatic melanoma.

Purified Astaxanthin from Haematococcus pluvialis Promotes Tissue Regeneration by Reducing Oxidative Stress and the Secretion of Collagen In Vitro and In Vivo

Intracellular reactive apoptosis and reactive oxygen species (ROS) play a crucial role in ultraviolet- (UV-) induced inflammation and aging reaction in human dermal tissues. This study determines the mechanism by which Haematococcus pluvialis extracts (HPE) and purified astaxanthin (HPA) to promote skin regeneration in the injured tissue in vitro and in vivo. The results show that HPE and HPA decrease the DNA damage and promote the secretion of collagen from the human normal fibroblast cell line (Hs68) in a dose-dependent manner. UV irradiation and HPA reduce oxidative stress damage due to phorbol-12-myristate-13-acetate (PMA). When skin cells are injured by free radicals, cells undergo a programmed cellular death. Cellular apoptotic death is determined using annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double staining to verify that there is no cell membrane asymmetry and that the nuclear membrane is broken. Inflammatory symptoms and apoptotic injuries to experimental rats in a group that is treated with HPA treated are decreased in a dose-dependent manner after UVB exposure (300 mJ/cm²) for 15 min in vivo, compared to the vehicle control group. These positive results show that HPA repairs UVB-triggered skin tissue injury and aging by conducting electrons out of cells to maintain a low level of oxidative stress so that collagen is synthesized in vitro and in vivo.

TGF-β3 suppresses melanogenesis in human melanocytes cocultured with UV-irradiated neighboring cells and human skin

BACKGROUND

Ultraviolet radiation (UVR) is the most well-known cause of skin pigmentation accompanied with photoaging. Transforming growth factor (TGF)-β1 was previously shown to have anti-melanogenic property; however, it can induce scarring in skin.

OBJECTIVE

We investigated the effect of TGF-β3 on melanogenesis in human melanocytes cocultured with UV-irradiated skin constituent cells, and UV-irradiated human skin.

METHODS

UVB irradiation or treatment with stem cell factor (SCF) and endothelin-1 (ET-1) was applied to human melanocytes cocultured with keratinocytes and/or fibroblasts and ex vivo human skin. Mechanistic pathways were further explored after treatment with TGF-β3.

RESULTS

While UVB irradiation or SCF/ET-1 enhanced melanogenesis, TGF-β3 effectively inhibited melanin accumulation and tyrosinase activity via downregulation of the extracellular signal-regulated kinase (ERK)/microphthalmia-associated transcription factor (MITF) pathway. TGF-β3 increased the expression of differentiation markers of keratinocytes.

CONCLUSION

TGF-β3 effectively suppressed UVR-stimulated melanogenesis indicating that topical TGF-β3 may be a suitable candidate for the treatment of UV-associated hyperpigmentation disorders.

Natural skin-whitening compounds for the treatment of melanogenesis (Review)

Melanogenesis is the process for the production of melanin, which is the primary cause of human skin pigmentation. Skin-whitening agents are commercially available for those who wish to have a lighter skin complexions. To date, although numerous natural compounds have been proposed to alleviate hyperpigmentation, insufficient attention has been focused on potential natural skin-whitening agents and their mechanism of action from the perspective of compound classification. In the present article, the synthetic process of melanogenesis and associated core signaling pathways are summarized. An overview of the list of natural skin-lightening agents, along with their compound classifications, is also presented, where their efficacy based on their respective mechanisms of action on melanogenesis is discussed.

Melanogenic Properties and Expression Profiles of Melanogenic Paracrine Molecules in Riehl's Melanosis

Riehl's melanosis is a hyperpigmentary disorder that occurs predominantly on the face and neck. To date, the pathogenesis of Riehl's melanosis with regards to the melanogenic properties and paracrine melanogenic molecules has not well been studied. This study was aimed to provide a novel perspective on the pathogenesis of Riehl's melanosis by identifying the relevant paracrine melanogenic molecules in Riehl's melanosis. Skin biopsies were performed on lesional and normal-appearing perilesional skin of 12 patients with Riehl's melanosis and 12 age- and sex-matched healthy controls. Histopathological and immunohistochemical staining for paracrine melanogenic molecules was analyzed. The major histopathological findings of Riehl's melanosis were basal hyperpigmentation, melanocyte proliferation, interface change, dermal pigmentary incontinence, vascular proliferation, and dermal inflammation. Dermal expression intensities of stem cell factor (SCF) and c-kit were increased in the lesional skin of Riehl's melanosis. In addition, increased expression of epidermal and dermal ET-1 was also observed in the lesional skin of Riehl's melanosis. Increased tissue expressions of SCF, c-kit, and ET-1 in Riehl's melanosis support the role of these paracrine melanogenic molecules in the pathogenesis of Riehl's melanosis. The findings from this study might present useful information on the pathogenetic mechanism of Riehl's melanosis.

Rationale and Roadmap for Developing Panels of Hotspot Cancer Driver Gene Mutations as Biomarkers of Cancer Risk

Cancer driver mutations (CDMs) are necessary and causal for carcinogenesis and have advantages as reporters of carcinogenic risk. However, little progress has been made toward developing measurements of CDMs as biomarkers for use in cancer risk assessment. Impediments for using a CDM-based metric to inform cancer risk include the complexity and stochastic nature of carcinogenesis, technical difficulty in quantifying low-frequency CDMs, and lack of established relationships between cancer driver mutant fractions and tumor incidence. Through literature review and database analyses, this review identifies the most promising targets to investigate as biomarkers of cancer risk. Mutational hotspots were discerned within the 20 most mutated genes across the 10 deadliest cancers. Forty genes were identified that encompass 108 mutational hotspot codons overrepresented in the COSMIC database; 424 different mutations within these hotspot codons account for approximately 63,000 tumors and their prevalence across tumor types is described. The review summarizes literature on the prevalence of CDMs in normal tissues and suggests such mutations are direct and indirect substrates for chemical carcinogenesis, which occurs in a spatially stochastic manner. Evidence that hotspot CDMs (hCDMs) frequently occur as tumor subpopulations is presented, indicating COSMIC data may underestimate mutation prevalence. Analyses of online databases show that genes containing hCDMs are enriched in functions related to intercellular communication. In its totality, the review provides a roadmap for the development of tissue-specific, CDM-based biomarkers of carcinogenic potential, comprised of batteries of hCDMs and can be measured by error-correct next-generation sequencing. Environ. Mol. Mutagen. 61:152-175, 2020. Published 2019. This article is a U.S. Government work and is in the public domain in the USA. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.

Rhododenol Activates Melanocytes and Induces Morphological Alteration at Sub-Cytotoxic Levels

Rhododenol (RD), a whitening cosmetic ingredient, was withdrawn from the market due to RD-induced leukoderma (RIL). While many attempts have been made to clarify the mechanism underlying RIL, RIL has not been fully understood yet. Indeed, affected subjects showed uneven skin pigmentation, but the features are different from vitiligo, a skin hypopigmentary disorder, alluding to events more complex than simple melanocyte cytotoxicity. Here, we discovered that rhododenol treatment reduced the number of melanocytes in a pigmented 3D human skin model, Melanoderm™, confirming the melanocyte toxicity of RD. Of note, melanocytes that survived in the RD treated tissues exhibited altered morphology, such as extended dendrites and increased cell sizes. Consistently with this, sub-cytotoxic level of RD increased cell size and elongated dendrites in B16 melanoma cells. Morphological changes of B16 cells were further confirmed in the immunocytochemistry of treated cells for actin and tubulin. Even more provoking, RD up-regulated the expression of tyrosinase and TRP1 in the survived B16 cells. Evaluation of mRNA expression of cytoskeletal proteins suggests that RD altered the cytoskeletal dynamic favoring cell size expansion and melanosome maturation. Collectively, these results suggest that RD not only induces cytotoxicity in melanocytes but also can lead to a profound perturbation of melanocyte integrity even at sub-cytotoxic levels.

Functional Analysis of Macromolecular Polysaccharides: Whitening, Moisturizing, Anti-Oxidant, and Cell Proliferation

In this research we utilized extracts from two different nature products, Achatina fulica and Heimiella retispora, to enhance skin moisturizing abilities, anti-oxidative properties, and cell proliferations. It was observed that two polysaccharides with anti-oxidative effects by chelating metal ions reduced oxidative stress and further blocked the formation of reactive oxygen species syntheses. To detect whether there was a similar effect within the cellular mechanism, a flow cytometry was applied for sensing the oxidative level and it was found that both materials inhibited the endogenous oxidative stress, which was induced by phorbol-12-myristate-13-acetate (PMA). Both polysaccharides also stimulated the production of collagen to maintain skin tightness and a moisturizing effect. In summary, we developed two macromolecular polysaccharides with potential applications in dermal care.

Inhibition of LPS-Induced Oxidative Damages and Potential Anti-Inflammatory Effects of Phyllanthus emblica Extract via Down-Regulating NF-κB, COX-2, and iNOS in RAW 264.7 Cells

Phyllanthus emblica is an edible nutraceutical and functional food in the Asia area with medicinal and nutritive importance. The fruit extract of P. emblica is currently considered to be one of the effective functional foods for flesh maintenance and disease treatments because of its antioxidative and immunomodulatory properties. We examined the antioxidant abilities of the fruit extract powder by carrying out 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, iron reducing power, and metal chelating activity analysis and showed excellent antioxidative results. In 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, the result showed that the samples had no cytotoxic effect on RAW 264.7 cells even at a high concentration of 2 mg/mL. To investigate its immunomodulatory function, our estimation was to treat it with lipopolysaccharide (LPS) in RAW 264.7 cells to present anti-inflammatory capacities. The extract decreased reactive oxygen species (ROS) production levels in a dose-dependent manner measured by flow cytometry. We also examined various inflammatory mRNAs and proteins, including nuclear factor-κB (NF-κB), inducible nitric oxide synthases (iNOS), and cyclooxygenase-2 (COX-2). In quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blotting assay, all three targets were decreased by the extract, also in a dose-dependent manner. In conclusion, P. emblica fruit extract powder not only lessened antioxidative stress damages, but also inhibited inflammatory reactions.

A juxtacrine/paracrine loop between C-Kit and stem cell factor promotes cancer stem cell survival in epithelial ovarian cancer

Receptors tyrosine kinase (RTK) enable normal and tumor cells to perceive and adapt to stimuli present in the microenvironment. These stimuli, also known as growth factors, are important molecular cues actively supporting cancer stem cell (CSC) self-renewal and viability. Since in epithelial ovarian cancer (EOC) the expression of c-Kit (CD117) has been identified as a CSC hallmark, we investigated the existence of a tumor growth-promoting loop between c-Kit and its ligand Stem Cell Factor (SCF). SCF exists as a soluble or transmembrane protein and through c-Kit interaction regulates cell viability, proliferation, and differentiation both in physiological and pathological conditions. High amounts of SCF were found in the ascitic effusions collected from EOC patients. While tumor cells and CSC only expressed the membrane-associated SCF isoform, both secreted and membrane-bound isoforms were expressed by tumor-associated macrophages (TAM, here shown to be M2-like) and fibroblasts (TAF). Circulating monocytes from EOC-bearing patients and healthy donors did not express both SCF isoforms. However, monocytes isolated from healthy donors produced SCF upon in vitro differentiation into macrophages, irrespectively of M1 or M2 polarization. In vitro, both SCF isoforms were able to activate the Akt pathway in c-Kit⁺ cells, and this effect was counteracted by the tyrosine kinase inhibitor imatinib. In addition, our results indicated that SCF could help c-Kit⁺ CSC survival in selective culture conditions and promote their canonical stemness properties, thus indicating the possible existence of a juxtacrine/paracrine circuit in EOC.