Activity Of Melanocytes Research Articles

Nearly complete hair re-pigmentation in an older patient treated with hydroxyurea for essential thrombocytosis

Introduction Employed in the treatment of malignancies and non-neoplastic conditions, hydroxyurea is associated with integumentary adverse effects, including skin discoloration, xerosis, pruritus, cutaneous atrophy, chronic leg ulcers, oral ulcerations, alopecia, and some nail abnormalities. Case Report A 77-year-old woman was diagnosed with essential thrombocytosis and started on low dose hydroxyurea. After 20 weeks of treatment, she experienced an unexpected change in hair color from gray to dark brown, without using hair dye or supplements. She later developed bilateral dorsal hand melanoderma, melanonychia, and onychodystrophy. Management and outcome It was decided to monitor the patient with no action taken as she was happy with this side effect of hydroxyurea. The platelet count has remained in excellent control. The dark brown hair color persisted over time. Discussion/Conclusion Hair hyperpigmentation likely occurred through melanocyte activation via hydroxyurea. Severe side effects may require dosage adjustments, while milder effects can be monitored closely. The newly observed hair color restoration in this case highlights potential dual (therapeutic and aesthetic) applications of this class of agents.

Correlating dermatoscopic features with immunohistochemical markers in basal cell carcinoma: a comprehensive analysis of 100 cases in Caucasian population.

Basal Cell Carcinoma (BCC) is the most common form of skin cancer, characterized by its low metastatic potential yet considerable diversity in clinical and dermatoscopic presentation. Advances in dermatoscopy have significantly improved the early detection of BCC, revealing specific patterns that guide diagnosis and management. Parallelly, immunohistochemical markers have been explored for their potential to elucidate the underlying tumor biology and prognosis, with particular focus on angiogenesis, melanocytic activity, and lymphangiogenesis. This study aims to investigate the correlations between dermatoscopic features and the immunohistochemical expressions of CD34, CD31, Melan-A, and D2-40 in BCC, through a comprehensive analysis of 100 cases We sought to determine whether visual dermatoscopic patterns correlate with the molecular characteristics defined by immunohistochemical staining, potentially enhancing diagnostic accuracy. A total of 100 cases of clinically and histopathologically confirmed BCC were prospectively analyzed, employing standard dermatoscopic techniques for lesion evaluation and immunohistochemical staining for CD34, CD31, Melan-A, and D2-40 to assess tumor angiogenic potential, melanocytic activity, and lymphangiogenesis. The study was conducted with adherence to ethical standards and informed consent from all participants. Dermatoscopic examination revealed a variety of vascular patterns and pigmented features across different BCC anatomical locations. However, the comprehensive correlation analysis predominantly found a lack of significant associations between dermatoscopic appearances and expressions of the targeted immunohistochemical markers, with the notable exception of a correlation between observed hemorrhage and the Melan-A marker. The lack of significant correlations between dermatoscopic features and immunohistochemical marker expressions in BCC suggests that the biological behavior and angiogenic, melanocytic, and lymphangiogenic activities within BCC lesions may be influenced by factors beyond those assessed in this study. Despite the exploratory nature of these findings, they underscore the complexity of BCC biology and highlight the need for further research incorporating additional markers and advanced imaging techniques.

Medical management of vitiligo: a narrative review

Vitiligo is a chronic cutaneous disease presenting with asymptomatic depigmented macular lesions without any signs of inflammation. Since time immemorial, treatment has been sought for this disorder due to the substantial stigma associated with it, more so in patients with skin of color. Vitiligo can be divided into two major clinical types − segmental vitiligo (SV) and non-segmental vitiligo (NSV). The pathophysiological basis for the loss of functional melanocytes resulting in vitiligo includes genetic predisposition, autoimmune mechanisms, and oxidative stress, among others. Thus, combination therapies targeting the autoimmune nature of disease, activation of melanocytes, and reduction of oxidative stress often yield a successful treatment response. There are very few FDA-approved options for vitiligo, and certain recently introduced modalities may modify the way vitiligo is conventionally treated. This review summarizes the conventional as well as the newer medical treatment options for different clinical types of vitiligo.

The Role of Vitamin A on the Histology of Skin of Adult Rats After Eposure to UVB

Background: long-term eposure of skin to sun (UV light) may produce different dermatological changes. The aim of this eperiment is to eplore the protective effects of oral vitamin A on skin subjected to UVB. Methods: twenty rats were separated into: group 1 (without UVB eposure), group 2 (eposed to single daily increasing dose of UVB for one week), group 3 (eposed to UVB with oral daily administration of vit A 10000 IU for one week), group 4 (received vit A for one week). The daily doses of UVB were respectively 0.24, 0.36, 0.48, 0.6, 0.72, 0.84 and 0.96 J/cm2. Skin samples were stained with hematoylin-eosin and Masson’s trichrome stains, in addition to Melan-A stain for melanocytes. Results: histopathological results in skin of group 2 demonstrated loss of normal architecture with increase in thickness of epidermis, hyperkeratosis and parakeratosis, moreover, skin sections detected increased number of inflammatory cells with damaged hair follicles. The basal layer shows an increase in mitotic division and necrosis, besides, epidermal edema and vascular congestion. Furthermore, collagen fibers were degraded. Immunohistochemical reaction revealed intense positive epression of Melan-A with increased proliferation and activity of melanocytes, while sections of groups 1 and 4 show normal healthy skin and negative Melan-A epression. In contrast, skin of group 3 reveals mild hyperkeratosis with normal keratin layer, in addition, the infiltration of inflammatory cells was dropped and hair follicles were preserved. Collagen bundles were slightly degraded with normal arrangement. Immunohistochemical results of this group show mild positive epression of Melan A. Conclusion: oral administration of vitamin A decreases the toic effect of UVB radiation on skin and reduces its induced pigmentation.

Unveiling the Potential of Ultrasonic-Assisted Ethanol Extract from Sargassum horneri in Inhibiting Tyrosinase Activity and Melanin Production in B16F10 Murine Melanocytes.

Melanogenesis, regulated by genetic, hormonal, and environmental factors, occurs in melanocytes in the basal layer of the epidermis. Dysregulation of this process can lead to various skin disorders, such as hyperpigmentation and hypopigmentation. Therefore, the present study investigated the effect of ultrasonic-assisted ethanol extract (SHUE) from Sargassum horneri (S. horneri), brown seaweed against melanogenesis in α-melanocyte-stimulating hormone (MSH)-stimulated B16F10 murine melanocytes. Firstly, yield and proximate compositional analysis of the samples were conducted. The effect of SHUE on cell viability has been evaluated by using 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. After that, the melanin content and cellular tyrosinase activity in α-MSH-stimulated B16F10 murine melanocytes were examined. Western blot analysis was carried out to investigate the protein expression levels of microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP1), and tyrosinase-related protein-2 (TRP2). In addition, the effect of extracellular signal-regulated kinase (ERK) on the melanogenesis process was assessed via Western blotting. As per the analysis, SHUE contained the highest average yield on a dry basis at 28.70 ± 3.21%. The findings showed that SHUE reduced the melanin content and cellular tyrosinase activity in α-MSH-stimulated B16F10 murine melanocytes. Additionally, the expression levels of MITF, TRP1, and TRP2 protein were significantly downregulated by SHUE treatment in α-MSH-stimulated B16F10 murine melanocytes. Moreover, SHUE upregulated the phosphorylation of ERK and AKT in α-MSH-stimulated B16F10 murine melanocytes. In addition, experiments conducted using the ERK inhibitor (PD98059) revealed that the activity of SHUE depends on the ERK signaling cascade. These results suggest that SHUE has an anti-melanogenic effect and can be used as a material in the formulation of cosmetics related to whitening and lightening.

Intra-operative dermoscopy (onychoscopy) of the nail unit-A systematic review.

Dermoscopy of the nail unit (onychoscopy) is a method which allows for non-invasive observation of the nail structures, increasing the accuracy of clinical diagnosis. Currently, it is used in evaluation of both inflammatory and neoplastic conditions of the nail unit. However, in contrast to the skin, the anatomy of the nail unit prevents direct observation of nail bed or nail matrix structure during classic onychoscopy. Intra-operative onychoscopy is a variant of the technique which uses direct visualization of the nail unit structures after nail plate avulsion. The aim of this systematic review was to summarize the current state of knowledge on intra-operative onychoscopy. The MEDLINE, EMBASE and Cochrane databases were systematically searched in January 2024. All types of study designs assessing intra-operative dermoscopy of the nail unit were included in this study. The risk of bias in included studies was assessed using the Joanna Briggs Institute critical appraisal tools. The qualitative synthesis of 19 studies totalling a number of 218 cases in 217 patients included the following entities: melanoma, nevus, hypermelanosis (melanocytic activation), melanocytic hyperplasia, melanophages accumulation, squamous cell carcinoma, glomus tumour, lichen planus, onychomatricoma, onychomycosis and subungual exostosis. The main limitation of the study was a relatively low number of identified studies, most with low levels of evidence. Intra-operative onychoscopy does not replace histologic examination, though it may be useful in determining the modality of surgical diagnostic procedures.

Melanocyte Density in the Diagnosis of Melanoma In Situ in Sun-Damaged Skin.

Histologic differentiation between melanoma in situ in chronically sun-damaged skin (CSDS) [lentigo maligna (LM)] and CSDS without malignancy is difficult because signs of melanocyte activation and proliferation are found in both. A potentially reliable and quantifiable criterion is melanocyte density (MD). Here, we evaluated whether and to what extent MD allows the distinction between LM and CSDS, which is particularly relevant for the evaluation of borderline cases and surgical margins.Articles assessing MD in LM and/or CSDS were evaluated in a systematic review. The results were categorized and compared according to staining. Cutoff values were included whenever stated.Twenty articles matched the selection criteria. Six hundred forty-four samples of CSDS and 227 samples of LM were considered. In each individual study, mean MD scores were higher for LM than for CSDS. However, looking at the overall study situation, it becomes clear that the data are very heterogeneous and show overlaps. Therefore, no reliable orientation value can be derived. Only 1 article defined a cutoff value.The data of MD in LM in contrast to CSDS were sparse, and a defined cutoff value was only mentioned in 1 article for microphthalmia-associated transcription factor, which cannot yet be generalized. Especially regarding the importance for the definition of surgical resection margins, this unsatisfactory data set highlights the need for further studies. More precise diagnostic criteria could spare some patients extensive and possibly disfiguring surgery.

Human Mesenchymal Stem Cell-Derived Exosomes Promote the Proliferation and Melanogenesis of Primary Melanocytes by Attenuating the H2O2-Related Cytotoxicity in vitro.

Mesenchymal stem cell-derived exosomes (MSC-Exo) have therapeutic potential. However, the impact of MSC-Exo on the survival and melanogenesis of human primary melanocytes following H2O2-induced damage has not been clarified. We therefore investigated the effects of MSC-Exo on the H2O2-affected survival of human primary melanocytes and their proliferation, apoptosis, senescence, and melanogenesis in vitro. MSC-Exo were prepared from human MSCs by sequential centrifugations and characterized by Transmission Electron Microscopy, Western blot and Nanoparticle Tracking Analysis. Human primary melanocytes were isolated and treated with different concentrations of MSC-Exo, followed by exposing to H2O2. Furthermore, the impact of pretreatment with MSC-Exo on the proliferation, apoptosis, senescence and melanogenesis of melanocytes were tested by CCK-8, flow cytometry, Western blot, L-Dopa staining, tyrosinase activity and RT-qPCR. Pretreatment with lower doses of MSC-Exo protected human primary melanocytes from the H2O2-triggered apoptosis, while pretreatment with higher doses of MSC-Exo enhanced the H2O2-induced melanocyte apoptosis. Compared with the untreated control, pretreatment with a lower dose (1 µg/mL) of MSC-Exo enhanced the proliferation of melanocytes, abrogated the H2O2-increased p53, p21, IL-1β, IL-6 and IL-8 expression and partially rescued the H2O2-decreased L-dopa staining reaction, tyrosinase activity, MITF and TRP1 expression in melanocytes. Our findings indicate that treatment with a low dose of MSC-Exo promotes the proliferation and melanogenesis of human primary melanocytes by ameliorating the H2O2-induced apoptosis and senescence of melanocytes. MSC-Exo may be a promising therapeutic strategy of vitiligo.

Adjuvant therapy with topical silymarin nanomicelles attenuates skin and hair depigmentation in a C57/BL6 mouse model of vitiligo

Nanomedicine holds great promise for delivering drugs to the skin. In this study, we explored the use of silymarin, a natural extract from Silybum marianum seeds, encapsulated in a micellar structure for topical treatment of vitiligo. The nanomicelles were characterized using dynamic light scattering (DLS). A C57/BL6 mouse model with vitiligo was utilized, and the depigmented skin area was topically treated with either silymarin nanomicelles or clobetasol for four consecutive weeks. Skin samples were collected for histopathological analysis and gene expression PCR analysis, while liver tissues were assessed for lipid peroxidation. DLS analysis revealed that more than 90% of the nanomicelles had a diameter below 30 nm and exhibited a narrow distribution. The in vivo study demonstrated that the nanomicellar form of silymarin was highly effective in suppressing vitiligo compared to clobetasol. Histopathological investigations indicated significant activation of melanocytes and reduced inflammation following treatment with silymarin nanomicelles. Moreover, lipid peroxidation analysis confirmed the antioxidant role of silymarin nanomicelles in scavenging reactive oxygen species. The downregulation of MITF, TRP1, and TRP2 expression following silymarin nanomicelle therapy was also found to be significant. Overall, the study demonstrated significant improvement of the depigmented skin patches, reduced skin inflammation, and downregulation of key genes involved in vitiligo, suggesting that silymarin nanomicelles hold promise as a viable therapeutic option for treating depigmented skin.

Melanosomal localization is required for GIF-2115/2250 to inhibit melanogenesis in B16F10 melanoma cells.

Tyrosinase inhibitors suppress melanogenesis in melanocytes. During a screening for tyrosinase inhibitors, however, we noticed some discrepancies in inhibitory efficacies between melanocytes and invitro assays. The compound (S)-N-{3-[4-(dimethylamino)phenyl]propyl}-N-methyl-indan-1-amine (GIF-2115) exerts antioxidative stress activity upon accumulation in late endosomes and lysosomes. GIF-2115 was also identified as a potent antimelanogenic reagent in B16F10 mouse melanoma cells. GIF-2115 inhibited the activity of mushroom tyrosinase and the lysates of B16F10 cells. However, structure-activity relationship studies indicated that GIF-2238, which lacks the benzene ring in the aminoindan structure of GIF-2115, inhibited tyrosinase activity invitro but did not inhibit melanogenesis in B16F10 cells. The aim of the present study is to show the importance of the intracellular distribution of tyrosinase inhibitors in exerting their antimelanogenic activity in melanocytes. The intracellular distribution of compounds was monitored by linking with the fluorescent group of 7-nitro-2,1,3-benzoxadiazole (NBD). To mislocalize GIF-2115 to mitochondria, the mitochondria-preferring fluoroprobe ATTO565 was used. We reconfirmed the localization of GIF-2250 (GIF-2115-NBD) not only to matured but also to early-stage melanosomes. Although GIF-2286 (GIF-2238-NBD) maintained tyrosinase inhibitory activity, it did not show specific intracellular localization. Moreover, when GIF-2115 was linked with ATTO565, the resultant compound GIF-2265 did not inhibit melanogenesis in B16F10 cells, despite its strong tyrosinase inhibitory activity. These results suggest that melanosomal localization is essential for the antimelanogenic activity of GIF-2115, and GIF-2115 derivatives may be new guides for drugs to endosomes and lysosomes as well as melanosomes.

Novel cellular systems unveil mucosal melanoma initiating cells and a role for PI3K/Akt/mTOR pathway in mucosal melanoma fitness

BackgroundMucosal Melanomas (MM) are highly aggressive neoplasms arising from mucosal melanocytes. Current treatments offer a limited survival benefit for patients with advanced MM; moreover, the lack of pre-clinical cellular systems has significantly limited the understanding of their immunobiology.MethodsFive novel cell lines were obtained from patient-derived biopsies of MM arising in the sino-nasal mucosa and designated as SN-MM1-5. The morphology, ultrastructure and melanocytic identity of SN-MM cell lines were validated by transmission electron microscopy and immunohistochemistry. Moreover, in vivo tumorigenicity of SN-MM1-5 was tested by subcutaneous injection in NOD/SCID mice. Molecular characterization of SN-MM cell lines was performed by a mass-spectrometry proteomic approach, and their sensitivity to PI3K chemical inhibitor LY294002 was validated by Akt activation, measured by pAkt(Ser473) and pAkt(Thr308) in immunoblots, and MTS assay.ResultsThis study reports the validation and functional characterization of five newly generated SN-MM cell lines. Compared to the normal counterpart, the proteomic profile of SN-MM is consistent with transformed melanocytes showing a heterogeneous degree of melanocytic differentiation and activation of cancer-related pathways. All SN-MM cell lines resulted tumorigenic in vivo and display recurrent structural variants according to aCGH analysis. Of relevance, the microscopic analysis of the corresponding xenotransplants allowed the identification of clusters of MITF-/CDH1-/CDH2 + /ZEB1 + /CD271 + cells, supporting the existence of melanoma-initiating cells also in MM, as confirmed in clinical samples. In vitro, SN-MM cell lines were sensitive to cisplatin, but not to temozolomide. Moreover, the proteomic analysis of SN-MM cell lines revealed that RICTOR, a subunit of mTORC2 complex, is the most significantly activated upstream regulator, suggesting a relevant role for the PI3K-Akt-mTOR pathway in these neoplasms. Consistently, phosphorylation of NDRG1 and Akt activation was observed in SN-MM, the latter being constitutive and sustained by PTEN loss in SN-MM2 and SN-MM3. The cell viability impairment induced by LY294002 confirmed a functional role for the PI3K-Akt-mTOR pathway in SN-MM cell lines.ConclusionsOverall, these novel and unique cellular systems represent relevant experimental tools for a better understanding of the biology of these neoplasms and, as an extension, to MM from other sites.

The Effectiveness Of Combination Vitamin D With Phototherapy For Vitiligo Treatment

Vitiligo represents a pigmentary skin disorder that impacts the layers of the skin, characterized by the absence of pigmentary cells in the epidermis, which causes the body to develop white patches and macules. However, additional research is necessary to comprehensively grasp the mechanisms that can be obtained using vitamin D with phototherapy for vitiligo treatment. Current evidence indicates that vitamin D substantially influences keratinocytes and melanocytes' activities through various mechanisms. Therefore, this literature review was organized to assess the effectiveness of combining vitamin D with phototherapy for vitiligo treatment. A search was conducted across four electronic journal databases: Google Scholar, PubMed, Taylor & Francis, and ScienceDirect. Inclusion criteria involved studies with vitiligo respondents, explaining the effectiveness of combining vitamin D with phototherapy for vitiligo treatment and detailing the benefits or harms of using this combination in vitiligo patients. Only five studies met the specified criteria and are consequently considered deserving of further assessment. The combination of phototherapy and vitamin D is postulated to manage vitiligo effectively. Phototherapy enhances repigmentation, ensuring a harmonious color reconciliation with the innate skin tone. Simultaneously, Vitamin D assumes a pivotal role in modulating the activity of keratinocytes and melanocytes, operating through diverse mechanisms. Based on this article review, it can be concluded that phototherapy with vitamin D is more effective in treating vitiligo than phototherapy only.

Anti-oxidative, anti-apoptotic, and anti-inflammatory activities of Connarus semidecandrus Jack ethanol extract in UVB-irradiated human keratinocytes

Ethnopharmacological relevanceConnarus semidecandrus Jack (Family: connaraceae) is a medicinal plant known for its wide distribution throughout Southeast Asia. Renowned for its diverse therapeutic properties, it has been traditionally used for treating fever, skin irritation, and colic. Aim of the studyNumerous individuals suffer from skin issues, including wrinkles, hyperpigmentation, and inflammation, due to environmental factors. Although many drugs are available to treat skin problems, chemical drugs have many shortcomings and side effects. Therefore, natural products are attractive potential medicines for alleviating skin troubles. We recently showed that Connarus semidecandrus Jack ethanol extract (Cs-EE) has anti-alopecia potential. This paper aims to explore the potential skin-protective effects and underlying molecular mechanisms of Connarus semidecandrus Jack in UVB-induced human keratinocytes (HaCaT). Materials and methodsBefore utilization, Cs-EE was dissolved in dimethyl sulfoxide (DMSO) and was preserved at a temperature of −20 °C. The phytochemical constituents of Cs-EE were detected by gas chromatography–mass spectrometry analysis (GC-MS). Sequentially, HaCaT cells were exposed to varying concentrations of Cs-EE prior to ultraviolet B (UVB) irradiation. Evaluations of cellular responses in HaCaT cells, including assessments of cell viability, deoxyribonucleic acid (DNA) damage, and gene and protein expressions, were carried out. To explore the specific signaling pathway involved, we conducted a luciferase assay in addition to validating these pathways using Western blot analysis. ResultsNitric oxide (NO) and intracellular reactive oxygen species were decreased. Melanin production through the activation of melanocytes by α-melanocyte-stimulating hormone (MSH) was also inhibited by Cs-EE. Furthermore, the mRNA expression levels of key factors such as cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), MMP-1, MMP-3, and MMP-9 exhibited a remarkable decrease. In addition, the phosphorylation of TAK1 within the signaling cascade exhibited a decline, and the activities of the transcription factor AP-1 were decreased according to a luciferase reporter assay. ConclusionsTaken together, these findings suggest that the anti-inflammatory, anti-aging, and anti-apoptotic effects of Cs-EE indicate the compound’s potential usefulness as a natural component in pharmaceutical and cosmetic products.

Cytoglobin functions as a redox regulator of melanogenesis in normal epidermal melanocytes.

Epidermal melanocytes are continuously exposed to sunlight-induced reactive oxygen species (ROS) and oxidative stress generated during the synthesis of melanin. Therefore, they have developed mechanisms that maintain normal redox homeostasis. Cytoglobin (CYGB), a ubiquitously expressed intracellular iron hexacoordinated globin, exhibits antioxidant activity and regulates the redox state of mammalian cells through its activities as peroxidase and nitric oxide (NO) dioxygenase. We postulated that CYGB functions in the melanogenic process as a regulator that maintains oxidative stress within a physiological level. This was examined by characterizing normal human melanocytes with the knockdown (KD) of CYGB using morphological and molecular biological criteria. CYGB-KD cells were larger, had more dendrites, and generated more melanin granules in the advanced stages of melanogenesis than control cells. The expression levels of major melanogenesis-associated genes and proteins were higher in CYGB-KD melanocytes than in wild type (WT) cells. As expected, CYGB-KD melanocytes generated more ROS and NO than WT cells. In conclusion, CYGB physiologically contributes to maintaining redox homeostasis in the melanogenic activity of normal melanocytes by controlling the intracellular levels of ROS and NO.

Seven Plus One Steps to Assess Pigmented Nail Bands (Melanonychia Striata Longitudinalis).

Melanonychia striata longitudinalis might involve one or more fingers and/or toes and might result from several different causes, including benign and malignant tumors, trauma, infections, and activation of melanocytes that might be reactive or related to the pigmentary trait, drugs and some rare syndromes. This broad differential diagnosis renders the clinical assessment of melanonychia striata particularly challenging. Nail matrix melanoma is relatively rare, occurs almost always in adults involves more frequently the first toe or thumb. The most common nail unit cancer, squamous cell carcinoma / Bowen disease (SCC) of the nail matrix is seldom pigmented. Histopathologic examination remains the gold standard for melanoma and SCC diagnosis, but excisional or partial biopsies from the nail matrix require training and is not routinely performed by the majority of clinicians. Furthermore, the histopathologic evaluation of melanocytic lesions of the nail matrix is particularly challenging, since early melanoma has only bland histopathologic alterations. Dermatoscopy of the nail plate and its free edge significantly improves the clinical diagnosis, since specific patterns have been associated to each one of the causes of melanonychia. Based on knowledge generated and published in the last decades, we propose herein a stepwise diagnostic approach for melanonychia striata longitudinalis: 1) Hemorrhage first 2) Age matters 3) Number of nails matters 4) Free edge matters 5) Brown or gray? 6) Size matters 7) Regular or irregular and, finally, "follow back".

Anti-melanogenic effect of exosomes derived from human dermal fibroblasts (BJ-5ta-Ex) in C57BL/6 mice and B16F10 melanoma cells.

Exosomes are involved in intercellular communication by transferring cargo between cells and altering the specific functions of the target cells. Recent studies have demonstrated the therapeutic effects of exosomes in several skin diseases. However, understanding of the effects of exosomes on anti-pigmentation is limited. Therefore, we investigated whether BJ-5ta exosomes (BJ-5ta-Ex) derived from human foreskin fibroblasts regulate melanogenesis and delineated the underlying mechanism. Interestingly, treatment with BJ-5ta-Ex induced decreased melanin content, tyrosinase (TYR) activity, and expression of melanogenesis-related genes, including microphthalmia-related transcription factor (MITF), TYR, tyrosinase-related protein-1 (TRP1), and tyrosinase-related protein-2 (TRP2). In addition, BJ-5ta-Ex downregulated the cAMP/PKA and GSK-3β/β-catenin signaling pathways and upregulated the MAPK/ERK signaling pathway. Notably, treatment with BJ-5ta-Ex inhibited α-melanocyte-stimulating hormone-induced melanosome transport and decreased the expression of key proteins involved in melanosome transport, namely, rab27a and melanophilin (MLPH). To further confirm the depigmenting effects of BJ-5ta-Ex, we conducted experiments using a three-dimensional reconstituted human full skin model and ultraviolet B (UVB)-irradiated mouse model. Treatment with BJ-5ta-Ex improved tissue brightness and reduced the distribution of melanosomes. In UVB-irradiated mouse ears, BJ-5ta-Ex reduced the number of active melanocytes and melanin granules. These results demonstrate that BJ-5ta-Ex can be useful for the clinical treatment of hyperpigmentation disorders.

Sargassum fusiforme Extract Induces Melanogenesis through the cAMP/PKA/CREB Signaling Pathway

The aim of this study was to investigate the effect of Sargassum fusiforme extract (SFE) on melanogenesis and its mechanism both in vitro and ex vivo. The melanogenic-inducing effect of SFE was evaluated using a melanin contents assay and a cellular tyrosinase activity assay. To investigate whether SFE could protect melanocytes against oxidative stress, hydrogen peroxidase was used. The molecular mechanism underlying the effect of SFE on melanogenesis was determined via Western blot analysis of tyrosinase, a microphthalmia-associated transcription factor (MITF), and a phosphorylated cAMP response element-binding protein (p-CREB) expression. The degree of pigmentation in a 3D skin model was determined by measuring the L* values. Contents of melanin in ex vivo human hair follicles were evaluated via Fontana–Masson staining. SFE significantly increased melanin contents and cellular tyrosinase activity in human epidermal melanocytes. SFE also increased the phosphorylation of CREB and the protein levels of tyrosinase and MITF. Moreover, SFE attenuated oxidative stress-induced cytotoxicity and depigmentation. Finally, the melanogenesis promoting effect of SFE was confirmed in both a 3D skin model and ex vivo human hair follicles. These findings suggest that SFE can induce melanogenesis via the cAMP/PKA/CREB signaling pathway in human epidermal melanocytes through its hyperpigmentation activity.

Combine with RNA-seq Reveals the Effect of Melatonin in the Synthesis of Melanin in Primary Melanocytes of Silky Fowls Black-Bone Chicken.

(1) Background: It was found that the melanin of black-bone chicken has various effects such as scavenging DPPH free radicals and anti-oxidation, and the synthesis of melanin is affected by various factors including hormones. In addition, several studies have found that melatonin affects the melanoma cell synthesis of melanin, which has not been reported in chicken primary melanocytes; so, relevant studies were conducted. (2) Methods: In this study, chicken primary melanocytes were isolated and characterized, and then melanocytes were treated with different concentrations of melatonin to investigate the effects of melatonin on melanin synthesis in chicken melanocytes in terms of melanin synthesis-related genes, melanin content, and tyrosinase activity, and combined with RNA seq to detect the change in gene expression level of chicken melanocytes after melatonin treatment. (3) Results: We isolated and characterized primary melanocytes, and indirect immunofluorescence assay results showed positive melanocyte marker genes. RT-qPCR results showed that melatonin decreased the expression of melanin synthesis-related genes. In addition, melatonin reduced the melanin content and decreased the tyrosinase activity of melanocytes in the treated group. A total of 1703 differentially expressed genes were screened by RNA-seq, and in addition, in the KEGG results, the signaling pathway associated with melanin synthesis, and the mTOR signaling pathway were enriched. (4) Conclusions: Melatonin could decrease the synthesis of melanin in chicken primary melanocytes.

Histopathological differences between vitiligo and lichen sclerosus et atrophicus using quantitative immunohistochemical analysis.

Lichen sclerosus et atrophicus (LS) is rare skin condition characterized by the presence of whitish patches primarily affecting the genital and perianal areas, though it can occur other parts of the body. LS may result in skin depigmentation without textural changes and should be differentiated from vitiligo. However, the histopathological features of hypopigmentation during vitiligo and LS have rarely been compared and have not been precisely described using quantitative immunohistochemical analysis. This study, therefore, aimed to investigate and compare the pigmentary characteristics of LS and vitiligo lesions using histochemical and immunohistochemical staining. We included 31 and 46 patients diagnosed with LS and vitiligo, respectively, at Ajou University Hospital between March 2009 and March 2020 in this study. Their medical charts and skin biopsy specimens were retrospectively reviewed. Additionally, Fontana-Masson staining for melanin and immunohistochemical staining for Melan-A, NKI/beteb, tyrosinase, and microphthalmia-associated transcription factor was performed. The melanin content, as well as the number of melanocytes was, in general, significantly higher in the epidermis of patients in the LS group compared with that in the vitiligo group. However, 22.6% of LS tissues showed less melanin pigmentation, 25.8% of LS specimens exhibited a lower number of melanocytes, and 29.0% of LS specimens demonstrated less melanocyte activity when compared with the average of vitiligo specimens. As lower melanin pigmentation and the near absence number of melanocytes were also observed in several LS specimens, both the clinical and histological findings must be comprehensively reviewed to differentiate vitiligo from LS.

The Histopathologic Evaluation of Diagnostic Procedures in Nail Melanoma.

The diagnostic delay in nail melanoma (NM) has been repeatedly emphasized. It may be related to both clinical misinterpretations and to errors in the bioptic procedure. To assess the efficacy of histopathologic examination in different diagnostic biopsies in NM. We retrospectively investigated the diagnostic procedures and histopathologic specimens referred to the Laboratory of Dermatopathology for the clinical suspicion of NM from January 2006 to January 2016. Eighty-six nail histopathologic specimens were analyzed consisting in 60 longitudinal, 23 punch and 3 tangential biopsies. A diagnosis of NM was performed in 20 cases, benign melanocytic activation in 51 cases and melanocytic nevi in 15 patients. Longitudinal and tangential biopsy were diagnostic in all cases, regardless of the clinical suspicion. Nail matrix punch biopsy instead was not diagnostic in most of the cases (13/23 specimens). In the presence of an NM clinical suspicion, longitudinal biopsy is recommended (lateral or median) because it provides exhaustive information on the characteristics of melanocytes morphology and distribution in all the components of the nail unit. Tangential biopsy, recently encouraged by expert authors due to the optimal surgical outcome, in our experience gives incomplete information on tumor extension. Punch matrix biopsy gives limited evidence in the diagnosis of NM.