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BACKGROUND: Quantification of melanin pigment release in pigment dispersion syndrome as well as observations of melanin brightness changes can be valuable information in the management of this rare ocular disease. OBJECTIVES: Previous studies have focused on examining the iris pigment epithelium and aqueous humor. Therefore, the aim of this study was to examine the cornea. METHODS: A novel technique was developed for this purpose based on aperture photometry. Slit lamp digital video images of the cornea were recorded. A single frame from each video recording based on the quality was chosen for further processing and analysis. Aperture photometry was performed with AstroImageJ open source software. Aperture selection was performed automatically. Melanin particles displaying a signal-to-noise ratio above 20 were analyzed. RESULTS: A total of 16 melanin particles from the right eye of the patient participating in the study were detected and a further 9 melanin particles from the left eye. The examined area of the cornea measured 348 × 348 pixels in the image. Brightness differed by as much as 8.98 × among particles in the right eye and 2.03 × in the left eye. CONCLUSIONS: It seems feasible for this new method to be potentially used in the monitoring of patients with pigment dispersion syndrome and pigmentary glaucoma as well as in other ocular diseases.

In this study, melanin from wild Auricularia auricula (WAA) was isolated using an ultra-high pressure (UHP)-assisted extraction method, and the physicochemical properties and antioxidant activity of WAA melanin were investigated. Under the optimized extraction conditions of a solid/liquid ratio of 1:30, a UHP of 450 MPa, a 22-min pressure holding time, a 1-mol/L NaOH concentration, and acid precipitation for 8 h, the WAA melanin extraction yield was 7.9 ± 0.16%. Moreover, the results showed that the surface of WAA melanin lacked structural order. Most melanin showed an average diameter of 1000 nm. WAA melanin had strong absorption at a wavelength of 210 nm and displayed typical characteristic absorption peaks. Moreover, WAA melanin contained 48.51% C, 6.88% H, 5.26% N, 0.45% S, and 38.90% O and may be a 3,4-dihydroxyphenylalanine melanin. An analysis of physicochemical properties showed that WAA melanin had good stability toward heat, light, and low concentrations of reducing agents and oxidizing agents. Furthermore, WAA melanin presented certain free radical scavenging activity. This study demonstrates that wild A. auricula melanin may have potential applications in the cosmetic or food industries as a natural antioxidant.

Although schizophrenia is associated with increased presynaptic dopamine function in the striatum, it remains unclear if neuromelanin levels, which are thought to serve as a biomarker for midbrain dopamine neuron function, are increased in patients with schizophrenia. We conducted a systematic review and meta-analysis of magnetic resonance imaging (MRI) and postmortem studies comparing neuromelanin (NM) levels between patients with schizophrenia and healthy controls (HCs). Standard mean differences were calculated to assess group differences in NM accumulation levels between patients with schizophrenia and HCs. This study included 7 articles in total. Five studies employed NM-sensitive MRI (NM-MRI) and two were postmortem brain studies. The patient group (n = 163) showed higher NM levels in the substantia nigra (SN) than HCs (n = 228) in both the analysis of the seven studies and the subgroup analysis of the 5 NM-MRI studies. This analysis suggest increased NM levels in the SN may be a potential biomarker for stratifying schizophrenia, warranting further research that accounts for the heterogeneity of this disorder.

Objective: To assess the utility of examining the nigrostriatal system with MRI and dopamine transporter (DAT) imaging for evaluating the preclinical phase of Parkinson’s disease (PD). Methods: The subjects were 32 patients with early PD and a history of probable rapid eye movement sleep behavior disorder (RBD; PD group), 15 patients with idiopathic RBD (RBD group), and 24 age-matched healthy controls (HC group) who underwent neuromelanin and diffusion tensor MRI for analysis of the substantia nigra pars compacta (SNpc). The RBD and PD groups underwent DAT imaging. In the RBD group, totals of 39 MRI and 27 DAT imaging examinations were obtained longitudinally. For each value, intergroup differences and receiver operating characteristic analysis for diagnostic performance were examined statistically. Results: The neuromelanin value was significantly lower and the diffusion tensor values except fractional anisotropy were significantly higher in the RBD and PD groups than in the HC group. The DAT specific binding ratio (SBR) was significantly lower in the PD group than in the RBD group. The areas under the receiver operating characteristic curves (AUCs) for neuromelanin/mean diffusivity value in the SNpc were 0.76/0.82 for diagnosing RBD and 0.83/0.80 for diagnosing PD. The area under the receiver operating characteristic curves for the SBR for discriminating PD from RBD was 0.87. Conclusion: MRI and DAT imaging may be useful for evaluating sequential nigrostriatal changes during the preclinical phase of PD. Advances in knowledge: MRI detects nigrostriatal changes in both RBD and early PD, and DAT imaging detects nigrostriatal changes during the transition to PD in RBD.

BACKGROUND Oral tranexamic acid (TA) has been an effective treatment for melasma with unclear mechanism. OBJECTIVE The present study aimed to demonstrate the effect of TA on melanogenesis via regulation of TGF-β1 expression in keratinocytes. METHODS We firstly determined the expression level of TGF-β1 in TA-treated keratinocyte-conditioned medium (KCM). Then the mRNA and protein levels of microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), and tyrosinase-related protein-1 (TRP-1) of human epidermal melanocytes (NHEMs) in presence of TA-treated KCM were evaluated via RT-PCR and Western blot analysis. Moreover, melanin content and tyrosinase activity were quantified. TGF-β1 gene was knocked down by small interfering RNA (siRNA) in keratinocytes. RESULTS The mRNA and protein levels of TGF-β1 in keratinocytes were significantly increased after TA treatment. Melanin contents, tyrosinase activity, protein and mRNA levels of TYR, MITF, and TRP-1 were downregulated in NHEMs in the presence of TA-treated KCM. Knockdown of TGF-β1 in keratinocytes could attenuate the inhibitory effect of TA-treated KCM on melanogenesis. CONCLUSION TA could stimulate TGF-β1 expression in keratinocytes, which further inhibits melanogenesis through the paracrine signaling.

Kaempferol, a representative flavonoid constituent of Sanguisorba officinalis, promotes melanogenesis, but the underlying mechanisms remain unknown. Here, we evaluated the effects of kaempferol on melanocytes morphology and behavior and determined the mechanisms regulating kaempferol-induced pigmentation. We observed that kaempferol increased melanin contents and dendritic length and stimulated melanocyte migration both in vitro and vivo. It significantly enhanced the expression of microphthalmia-associated transcription factor (MITF) and downstream enzymes of melanin biosynthesis—tyrosinase (TYR), tyrosinase-related protein (TRP-1), and dopachrome tautomerase (DCT). It also induced melanosome maturation (increased stage III and IV melanosomes) and melanin transfer to dendritic tips; this was evidenced as follows: kaempferol-treated melanocytes exhibited the perimembranous accumulation of HMB45-positive melanosomes and increased the expression of Rab27A, RhoA, and Cdc42, which improved melanosome transport to perimembranous actin filaments. These results jointly indicated that kaempferol promotes melanogenesis and melanocyte growth. Additionally, kaempferol stimulated the phosphorylation of P38/ERK MAPK and downregulated p-PI3K, p-AKT, and p-P70s6K expression. Pre-incubation with P38 (SB203580) and ERK (PD98059) signaling inhibitors reversed the melanogenic and dendritic effects and MITF expression. PI3K/AKT inhibitor augmented kaempferol-induced melanin content and dendrite length. In summary, kaempferol regulated melanocytes’ dendritic growth and melanosome quantity, maturation, and transport via P38/ERK MAPK and PI3K/AKT signaling pathways.

Purpose Development and performance measurement of a fully automated pipeline that localizes and segments the locus coeruleus in so-called neuromelanin-sensitive magnetic resonance imaging data for the derivation of quantitative biomarkers of neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. Methods We propose a pipeline composed of several 3D-Unet-based convolutional neural networks for iterative multi-scale localization and multi-rater segmentation and non-deep learning-based components for automated biomarker extraction. We trained on the healthy aging cohort and did not carry out any adaption or fine-tuning prior to the application to Parkinson’s disease subjects. Results The localization and segmentation pipeline demonstrated sufficient performance as measured by Euclidean distance (on average around 1.3mm on healthy aging subjects and 2.2mm in Parkinson’s disease subjects) and Dice similarity coefficient (overall around $$71\%$$ 71 % on healthy aging subjects and $$60\%$$ 60 % for subjects with Parkinson’s disease) as well as promising agreement with respect to contrast ratios in terms of intraclass correlation coefficient of $$\ge 0.80$$ ≥ 0.80 for healthy aging subjects compared to a manual segmentation procedure. Lower values ($$\ge 0.48$$ ≥ 0.48 ) for Parkinson’s disease subjects indicate the need for further investigation and tests before the application to clinical samples. Conclusion These promising results suggest the usability of the proposed algorithm for data of healthy aging subjects and pave the way for further investigations using this approach on different clinical datasets to validate its practical usability more conclusively.

In this study, we examined the effect of C. japonicum flower extract (CFE) on melanogenesis and its mechanism in vitro and ex vivo.The effect of CFE on melanogenesis was investigated with lightly (HEMn-LP) and moderately (HEMn-MP) pigmented normal human melanocytes, reconstituted three-dimensional skin (3D skin) model and ex vivo human hair follicles. The melanogenesis-inducing effect of CFE was evaluated using melanin content and intracellular tyrosinase activity assay. The amount and type of eumelanin and pheomelanin were analysed by using HPLC method. The mechanism involved in the effect of CFE on hyperpigmentation was explored by cyclic adenosine monophosphate (cAMP) immunoassay and western blot analysis for tyrosinase, microphthalmia-associated transcription factor (MITF) and phosphorylated CRE-binding protein (pCREB) expression. The degree of pigmentation in 3D skin and L-values were measured using a CR-300 chroma meter. The amount of dissolved melanin was measured using a spectrophotometer. The content of melanin in the hair follicles was evaluated by Fontana Masson staining.C. japonicum flower extract significantly increased the melanin content and cellular tyrosinase activity in both HEMn-LP and HEMn-MP cells. The markers of pheomelanin and eumelanin in HEMn-LP and HEMn-MP were also increased by CFE. We observed that CFE treatment on melanocytes increased intracellular cAMP with inducing pCREB and up-regulating the protein levels of TYR and MITF. Furthermore, CFE considerably increased the melanin content in a 3D skin model and ex vivo human hair follicles.These results suggest that CFE exerts hyperpigmentation activity through cAMP signalling in human melanocytes that it can improve follicular depigmentation and vitiligo by stimulating the melanin synthesis.Dans cette étude, nous avons examiné l'effet de l'extrait de fleur de C. japonicum (EFC) sur la mélanogenèse et son mécanisme in vitro et ex vivo. MÉTHODES: L'effet du EFC sur la mélanogenèse a été étudié avec des mélanocytes humains normaux légèrement (HEMn-LP) et modérément (HEMn-MP) pigmentés, un modèle de peau reconstituée en 3 dimensions (peau 3D) et des follicules pileux ex vivo. L'effet inducteur de la mélanogénèse de la EFC a été évalué en utilisant la teneur en mélanine et le dosage de l'activité de la tyrosinase intracellulaire. La quantité et le type d'eumélanine et de phéomélanine ont été analysés en utilisant la méthode HPLC. Le mécanisme impliqué dans l'effet de la EFC sur l'hyperpigmentation a été exploré par immunoessai à l'adénosine monophosphate cyclique (AMPc) et Western blot pour l'expression de la tyrosinase, du facteur de transcription associé à la microphtalmie (MITF) et l’expression de la protéine CREB phosphorylée. Le degré de pigmentation de la peau 3D, les valeurs L ont été mesurées à l'aide d'un chromamètre CR-300. La quantité de mélanine dissoute a été mesurée à l'aide d'un spectrophotomètre. La teneur en mélanine des follicules pileux a été évaluée par coloration Fontana Masson. RÉSULTATS: EFC a augmenté de manière significative la teneur en mélanine et l'activité de la tyrosinase cellulaire dans les cellules HEMn-LP et HEMn-MP. Les marqueurs de phéomélanine et d'eumélanine dans HEMn-LP et HEMn-MP ont également été augmentés par EFC. Nous avons observé que le traitement EFC sur les mélanocytes augmentait l'AMPc intracellulaire en induisant pCREB et en régulant à la hausse les niveaux de protéines de TYR et MITF. De plus, le EFC a considérablement augmenté la teneur en mélanine dans un modèle de peau 3D et dans les follicules pileux humains ex vivo.Ces résultats suggèrent que la EFC exerce une activité d'hyperpigmentation via la signalisation de l'AMPc dans les mélanocytes humains qu'elle peut améliorer la dépigmentation folliculaire et le vitiligo en stimulant la synthèse de mélanine.

Introduction Imiquimod plays an important role in the management of condyloma and premalignant lesions. Successively, an increase of hypopigmented lesions following imiquimod application has been reported. However, the mechanisms of imiquimod on melanocytes remain unclear. This study was designed to assess the effect of Imiquimod on the functions of melanocytes in vitro. Methods Primary cultured melanocytes were isolated from normal control skin tissue. After incubation with imiquimod for 48 h in vitro, cell viability was analyzed by cell counting kit‐8 assay. Apoptosis was detected using the Annexin V‐fluorescein‐5‐isothiocyanate flow cytometry assay. Melanin content and tyrosinase activity in melanocytes were measured by colorimetric method and the modified dopachrome method. The production of inflammatory cytokine interleukin 8 (IL‐8), IL‐6, and soluble ICAM‐1 (soluble Intercellular Adhesion Molecule‐1[sICAM‐1]) in melanocytes were measured by enzyme‐linked immunosorbent assay (ELISA). Toll‐like receptor 7 (TLR7), toll‐like receptor 9 (TLR9) protein, and autophagy‐related proteins microtubule‐associated protein 1A/1B‐light chain 3 (LC3‐II), p62, mechanistic target of rapamycin (mTOR), and Atg5 were assessed using western blot analysis. Results Imiquimod significantly inhibited the activity of tyrosinase activity and decreased melanin content in melanocytes and significantly increased apoptosis and IL‐6, IL‐8, and sICAM‐1 production in melanocytes. Moreover, the expression of TLR7 and TLR9 proteins were significantly increased, and the expression of mTOR, p62 protein were markedly decreased, but the expression of LC3II/I and Atg5 protein were significantly increased in melanocytes after incubating with imiquimod. Conclusions This study shows that imiquimod directly inhibits melanogenesis and increases melanocyte apoptosis rates. These effects combined with the upregulation of TLR7 and TLR9 together with increased autophagy activity and inflammatory cytokines production, might be the main reasons leading to hypopigmented lesions after imiquimod application., Imiquimod induces melanogenesis, activates autophagy, increases apoptosis in melanocytes, and stimulates the secretion of proinflammatory cytokines interleukin 6 (IL‐6), IL‐8 and soluble ICAM‐1 (sICAM‐1) as well as the expression of Toll‐like receptor 7 (TLR7) and toll‐like receptor 9 (TLR9) in melanocytes. These results suggest a possible mechanism causing imiquimod induced hypopigmentation. Physicians should be aware of this possible side effect that could be irreversible and difficult for the patient to accept.

Background: Although CREB phosphorylation is known to be essential in UVB/cAMP-stimulated melanogenesis, CREB null mice did not show identifiable pigmentation phenotypes. Here, we show that CREB-regulated transcription co-activator 3 (CRTC3) quantitatively regulates and orchestrates melanogenesis by directly targeting microphthalmia-associated transcription factor (MITF) and regulating the expression of most key melanogenesis-related genes. Methods: We analyzed CRTC3-null, KRT14-SCF transgenic, and their crossover mice. The molecular basis of CRTC3 effects on pigmentation was investigated by histology, melanin/tyrosinase assay, immunoblotting, shRNA, promoter assay, qRT-PCR, and subcellular localization. These analyses were carried out in primary cultured melanocytes, mouse cell lines, normal human cells, co-cultures, and ex vivo human skin. CRTC/CREB activity screening was performed to identify candidate agents for the regulation of melanogenesis. Results: The coat and skin color of CRTC3-null mice was paler due to a reduction in melanin deposition. Melanogenesis-related genes were reduced in CRTC3-deficient cultured melanocytes and tail skin of CRTC3-null mice. Notably, basal levels of MITF present in CRTC3-null mice were sufficient for melanocytic differentiation/survival. Thus CRTC3-null mice showed a comparable number of epidermal melanocytes compared to control mice. Stem cell factor (SCF) introduction by crossing with KRT14-SCF mice increased epidermal melanocytes and melanin deposition in control and CRTC3-null mice, but the skin color remained still light on the CRTC3-null background. Furthermore, we identified the therapeutic potential of altiratinib to inhibit melanogenesis in human melanocytes and human skin effectively and safely. Conclusion: CRTC3 appears to be a key sensor for melanogenesis and can be used as a reversible and tunable tool for selectively regulating melanogenesis without affecting melanocyte integrity. Thus, CRTC3 can also serve as a screening tool for the discovery of ideal melanogenesis-modulating small molecules.

Background: Neuromelanin-sensitive magnetic resonance imaging (NM-MRI) is a validated measure of neuromelanin concentration in the substantia nigra–ventral tegmental area (SN–VTA) complex and is a proxy measure of dopaminergic function with potential as a noninvasive biomarker. The development of generalizable biomarkers requires large-scale samples necessitating harmonization approaches to combine data collected across sites. Purpose: To develop a method to harmonize NM-MRI across scanners and sites. Study Type: Prospective. Population: A total of 128 healthy subjects (18–73 years old; 45% female) from three sites and five MRI scanners. Field Strength/Sequence: 3.0 T; NM-MRI two-dimensional gradient-recalled echo with magnetization-transfer pulse and three-dimensional T1-weighted images. Assessment: NM-MRI contrast (contrast-to-noise ratio [CNR]) maps were calculated and CNR values within the SN–VTA (defined previously by manual tracing on a standardized NM-MRI template) were determined before harmonization (raw CNR) and after ComBat harmonization (harmonized CNR). Scanner differences were assessed by calculating the classification accuracy of a support vector machine (SVM). To assess the effect of harmonization on biological variability, support vector regression (SVR) was used to predict age and the difference in goodness-of-fit (Δr) was calculated as the correlation (between actual and predicted ages) for the harmonized CNR minus the correlation for the raw CNR. Statistical Tests: Permutation tests were used to determine if SVM classification accuracy was above chance level and if SVR Δr was significant. A P-value

INTRODUCTION Melasma remains a recurrent, chronic, therapeutically challenging, and psychologically burdening condition. Several different modalities and approaches have been utilized, and some with notable success to experimentally manage the condition. Cysteamines, with their depigmentation properties, have only recently been intensely studied. One such formulation is the topical 5% cysteamine hydrochloride, the structure of which is notably more stable and with a less foul odor than its prior counterparts. We, therefore, aimed to assess the efficacy of the mentioned formulation in the treatment of melasma. METHODS The PubMed, SCOPUS, ISI Web of Science, and Embase, Cochrane, and Proquest databases were thoroughly searched for English studies evaluating the effects of the topical agent mentioned. RESULTS Eight studies (five RCTs, two case reports, and one case series) were included after three rounds of screening, most of which were carried out in Iran. Statistical significance was noted when assessing decreased melanin content and satisfaction rates. CONCLUSIONS It appears that the cysteamine cream could be comparably efficient in treating melasma while accompanied only by minor and transient adverse events. However, current evidence is limited by insufficient sample size, long-term follow-up, and only to epidermal melasma, highlighting the need for appropriately designed randomized controlled clinical trials to draw a conclusive image of the cysteamine's role in treating this recalcitrant condition.

Purpose Obtaining tumour-free margins is critical for avoiding re-excision and reducing local recurrence following breast-conserving surgery; however, it remains challenging. Imaging-guided surgery provides precise detection of residual lesions and assists surgical resection. Herein, we described water-soluble melanin nanoparticles (MNPs) conjugated with cyclic Arg-Gly-Asp (cRGD) peptides for breast cancer photoacoustic imaging (PAI) and surgical navigation. Methods The cRGD-MNPs were synthesised and characterized for morphology, photoacoustic characteristics and stability. Tumour targeting and toxicity of cRGD-MNPs were determined by using either breast cancer cells, MDA-MB-231 tumour-bearing mice or the FVB/N-Tg (MMTV-PyVT) 634Mul/J mice model. PAI was used to locate the tumour and guide surgical resection in MDA-MB-231 tumour-bearing mice. Results The cRGD-MNPs exhibited excellent in vitro and in vivo tumour targeting with low toxicity. Intravenous administration of cRGD-MNPs to MDA-MB-231 tumour-bearing mice showed an approximately 2.1-fold enhancement in photoacoustic (PA) intensity at 2 h, and the ratio of the PA intensity at the tumour site to that in the surrounding normal tissue was 3.2 ± 0.1, which was higher than that using MNPs (1.7 ± 0.3). Similarly, the PA signal in the spontaneous breast cancer increased ~ 2.5-fold at 2 h post-injection of cRGD-MNPs in MMTV-PyVT transgenic mice. Preoperative PAI assessed tumour volume and offered three-dimensional (3D) reconstruction images for accurate surgical planning. Surgical resection following real-time PAI showed high consistency with histopathological analysis. Conclusion These results highlight that cRGD-MNP-mediated PAI provide a powerful tool for breast cancer imaging and precise tumour resection. cRGD-MNPs with fine PA properties have great potential for clinical translation.

The locus coeruleus (LC), a tiny nucleus in the brainstem and the principal site of noradrenaline synthesis, has a major role in regulating autonomic function, arousal, attention, and neuroinflammation. LC dysfunction has been linked to a range of disorders; however particular interest is given to the role it plays in Alzheimer’s disease (AD). The LC undergoes significant neuronal loss in AD, thought to occur early in the disease process. While neuronal loss in the LC has also been suggested to occur in aging, this relationship is less clear as the findings have been contradictory. LC density has been suggested to be indicative of cognitive reserve and the evidence for these claims will be discussed. Recent imaging techniques allowing visualization of the LC in vivo using neuromelanin-sensitive MRI are developing our understanding of the role of LC in aging and AD. Tau pathology within the LC is evident at an early age in most individuals; however, the relationship between tau accumulation and neuronal loss and why some individuals then develop AD is not understood. Neuromelanin pigment accumulates within LC cells with age and is proposed to be toxic and inflammatory when released into the extracellular environment. This review will explore our current knowledge of the LC changes in both aging and AD from postmortem, imaging, and experimental studies. We will discuss the reasons behind the susceptibility of the LC to neuronal loss, with a focus on the role of extracellular neuromelanin and neuroinflammation caused by the dysfunction of the LC-noradrenaline pathway.

Melanin is a widely distributed phenolic pigment that is biosynthesized from tyrosine and its hydroxylated product, dopa, in all animals. However, recent studies reveal a significant deviation from this paradigm, as insects appear to use dopamine rather than dopa as the major precursor of melanin. This observation calls for a reconsideration of the insect melanogenic pathway. While phenoloxidases and laccases can oxidize dopamine for dopaminechrome production, the fate of dopaminechrome remains undetermined. Dopachrome decarboxylase/tautomerase, encoded by yellow-f/f2 of Drosophila melanogaster, can convert dopaminechrome into 5,6-dihydroxyindole, but the same enzyme from other organisms does not act on dopaminechrome, suggesting the existence of a specific dopaminechrome tautomerase (DPT). We now report the identification of this novel enzyme that biosynthesizes 5,6-dihydroxyindole from dopaminechrome in Drosophila. Dopaminechrome tautomerase acted on both dopaminechrome and N-methyl dopaminechrome but not on dopachrome or other aminochromes tested. Our biochemical and molecular studies reveal that this enzyme is encoded by the yellow-h gene, a member of the yellow gene family, and advance our understanding of the physiological functions of this gene family. Identification and characterization of DPT clarifies the precursor for melanin biosynthetic pathways and proves the existence of an independent melanogenic pathway in insects that utilizes dopamine as the primary precursor.

Chronic sleep restriction (CSR) is common in modern society, adversely affecting cognitive performance and health. Yet how it impacts neurons regulating sleep remains unclear. Several studies using mice reported substantial losses of wake-active orexin/hypocretin and locus coeruleus (LC) noradrenergic neurons, but not rapid eye movement sleep-active melanin-concentrating hormone (MCH) neurons, following CSR. Here, we used immunohistochemistry and stereology to examine orexin, MCH and LC noradrenergic neurons in a rat model of CSR that uses programmed wheel rotation (3 h on/1 h off; '3/1' protocol). Adult male Wistar rats underwent one or four cycles of the 4-day 3/1 CSR protocol, with 2-day recovery between cycles in home cages. Time-matched control rats were housed in locked wheels/home cages. We found no significant differences in the numbers of orexin, MCH and LC noradrenergic neurons following either one- or four-cycle CSR protocol compared to respective controls. Similarly, the four-cycle CSR protocol had no effect on the densities of orexin axon terminals in the LC, noradrenergic dendrites in the LC and noradrenergic axon terminals in the frontal cortex. Body weights, however, decreased after one cycle of CSR and then increased with diminishing slope over the next three cycles. Thus, we found no evidence for loss of orexin or LC noradrenergic neurons following one and four cycles of the 4-day 3/1 CSR protocol in rats. Differences in CSR protocols and/or possible species differences in neuronal vulnerability to sleep loss may account for the discrepancy between the current results in rats and previous findings in mice.

Eosinophilic solid and cystic renal cell carcinoma (ESC-RCC) is an emerging entity in renal neoplasia with distinctive histopathological findings and a generally favorable prognosis. The presence of melanin pigment in a renal tumor typically prompts the observer to consider the microphthalmia-associated transcription family translocation renal cell carcinomas. We present a renal tumor occurring in a 19-year-old male patient which had the typical morphology of ESC-RCC but showed the additional finding of focal melanin pigment. This tumor showed strong and diffuse positive immunolabeling with paired box gene 8 and cytokeratin 20, and was negative with epithelial membrane antigen, carbonic anhydrase 9, CD117, cytokeratin 7, and transcription factor E3. Human melanoma black-45 showed focal positivity, but Melan-A was negative. Next-generation sequencing revealed a mutation in the TSC2 gene (c.4490C > G, p.[Pro1497Arg] and c.1257 + 1del) and break apart fluorescence in-situ hybridization with TFE3 and TFEB probes was negative. In this case report, we present the novel finding of melanin pigment occurring in a genetically proven and otherwise typical ESC-RCC, and briefly discuss the differential diagnostic considerations.

Introduction: Bathing in the Blue Lagoon (BL) in Iceland benefits patients with psoriasis. Accordingly, the BL water contains algae with biological activities that improve skin barrier function and affect T-cell responses relevant for psoriasis. Bathing in the BL is also becoming increasingly popular among healthy individuals and anecdotal evidence suggests positive effects on uneven skin pigmentation. Objective: The aim of the study was to address the impact of BL algae on skin pigmentation. Methods: In this work, in vitro gene expression studies in melanocytes and a noninvasive in vivo study were conducted. Results: We here report that normal human epidermal melanocytes, which had been treated with nontoxic concentrations of BL algae, show a significantly reduced expression of α melanocyte-stimulating hormone-induced expression of genes important for melanin synthesis, such as tyrosinase, tyrosinase-related protein 1, dopachrome tautomerase, melan A protein, and pre-melanosome protein. This in vitro observation prompted us to conduct a randomized, double-blind, intra-individual, comparative split-face in vivo study, in which 60 volunteers with pre-existing facial pigment spots were treated twice daily with a BL algae containing serum or a vehicle control. We found that constitutive skin pigmentation as determined by colorimetry (individual typology angle and luminescence) did not differ significantly between vehicle- and serum-treated skin sites. In marked contrast, digital photography under cross-polarized lighting and RBX technology (VISIA CR) revealed that the number of pigment spots in the serum-treated face decreased significantly compared to the vehicle-treated side. Conclusion: Thus, BL algae can affect human melanocyte function in vitro and reduce uneven facial skin pigmentation in vivo.

There is an increasing recognition of ethnic dermatology to reflect the increase in skin of colour (SOC) populations in the UK. Hyperpigmentary disorder is one of the commonest skin concerns in SOC but there has been limited training available in this field of dermatology. Variations in skin colour are genetically determined by the amount of melanin content, the eumelanin/pheomelanin ratio and the size of melanosomes, but is also influenced by other factors such as hormones and extrinsic factors such as ultraviolet radiation. Hyperpigmentation is a broad term to describe increased pigmentation in the skin, and making a correct diagnosis is an important first step in the successful management of hyperpigmentary disorders. A systematic approach based on the disease pathogenesis (e.g. reactive vs. nonreactive, increased melanin vs. increased number of cells or epidermal vs. dermal pigmentation) aided by a detailed history and clinical examination is the best way to diagnose a hyperpigmentary disorder. Based on its pathogenesis, management can be planned. For epidermal hyperpigmentation caused by increased melanin, topical skin-lightening agents targeting inhibition of tyrosinase or melanosome transfer and promotion of keratinocyte turnover can be used. Hydroquinone-containing cream is the gold-standard treatment for epidermal hyperpigmentation. Alternative treatments include laser toning or chemical peels. However, increased dermal pigmentation is more challenging to target with topical treatments. If hyperpigmentation is due to increased numbers of melanocytes or keratinocytes, high-fluence laser is the most appropriate treatment method.

Plant tissue culture holds immense potential for the production of secondary metabolites with various physiological functions. We recently established a plant tissue culture system capable of producing secondary metabolites from Aster yomena. This study aimed to uncover the mechanisms underlying the potential therapeutic effects of Aster yomena callus pellet extract (AYC-P-E) on photoaging-induced skin pigmentation. Excessive melanogenesis was induced in B16F10 melanoma cells using α-melanocyte stimulating hormone (α-MSH). The effects of AYC-P-E treatment on melanin biosynthesis inducers and melanin synthesis inhibition were assessed. Based on the results, a clinical study was conducted in subjects with skin pigmentation. AYC-P-E inhibited melanogenesis in α-MSH-treated B16F10 cells, accompanied by decreased mRNA and protein expression of melanin biosynthesis inducers, including cyclic AMP response element-binding protein (CREB), tyrosinase, microphthalmia-associated transcription factor (MITF), tyrosinase related protein-1 (TRP-1), and TRP-2. This anti-melanogenic effect was mediated by mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) and protein kinase B (AKT) phosphorylation. Treatment of subjects with skin pigmentation with AYC-P-E-containing cream formulations resulted in 3.33%, 7.06%, and 8.68% improvement in the melanin levels at 2, 4, and 8 weeks, respectively. Our findings suggest that AYC-P-E inhibits excessive melanogenesis by activating MEK/ERK and AKT signaling, potentiating its cosmetic applications in hyperpigmentation treatment.

Background Melanin plays important roles in determining human skin color and protecting human skin cells against harmful ultraviolet light. However, abnormal hyperpigmentation in some areas of the skin may become aesthetically unpleasing, resulting in the need for effective agents or methods to regulate undesirable hyperpigmentation. Objective We investigated the effect of harmine, a natural harmala alkaloid belonging to the beta-carboline family, on melanin synthesis and further explored the signaling pathways involved in its mechanism of action. Methods Human MNT-1 melanoma cells and human primary melanocytes were treated with harmine, chemical inhibitors, small interfering RNAs, or mammalian expression vectors. Cell viability, melanin content, and expression of various target molecules were assessed. Results Harmine decreased melanin synthesis and tyrosinase expression in human MNT-1 melanoma cells. Inhibition of DYRK1A, a harmine target, decreased melanin synthesis and tyrosinase expression. Further studies revealed that nuclear translocation of NFATC3, a potential DYRK1A substrate, was induced via the harmine/DYRK1A pathway and that NFATC3 knockdown increased melanin synthesis and tyrosinase expression. Suppression of melanin synthesis and tyrosinase expression via the harmine/DYRK1A pathway was significantly attenuated by NFATC3 knockdown. Furthermore, harmine also decreased melanin synthesis and tyrosinase expression through regulation of NFATC3 in human primary melanocytes. Conclusion Our results indicate that harmine decreases melanin synthesis through regulation of the DYRK1A/NFATC3 pathway and suggest that the DYRK1A/NFATC3 pathway may be a potential target for the development of depigmenting agents.

Laryngeal cancer is highly aggressive and insensitive to conventional targeted therapies, which often result in poor therapeutic outcomes. Image-guided precision therapy is a promising strategy in oncology that has superior safety and efficacy versus conventional therapies. Here, we present a multifunctional theranostic nanoplatform based on melanin-coated gold nanorod (GNR) that exhibits excellent multimodal imaging ability and photothermal effects. These attributes make the platform applicable for multimodal photoacoustic (PA)/positron emission tomography (PET)/magnetic resonance (MR) image-guided photothermal treatment of laryngeal cancer. The melanin nanoparticles markedly suppress the cytotoxicity of the template cetyltrimethylammonium bromide bilayer and conferred the GNR with excellent PET/MR imaging performances, due to their native biocompatibilities and strong affinities to metal ions. Moreover, the introduction of GNR to the melanin nanoparticles greatly improved the near-infrared absorbances and passive targeting capabilities, leading to exceptional PA imaging and photothermal ablation of tumors. The nanoplatform exhibits high stability and dispersity under physiological conditions. After intravenous injection, the nanoplatform could be precisely tracked

Ultraviolet irradiation induces melanin accumulation, which can be reduced by the use of chemical whitening products. However, the associated safety concerns of such products have prompted the search for natural and harmless alternatives. This study aimed to identify a natural acidic formulation to reduce skin pigmentation. The metabolite propionic acid (CH3CH2COOH, PA) was the most abundant fatty acid in the filtrate from Pluronic F68 (PF68) fermentation of Cutibacterium acnes (C. acnes) and reduced the DOPA-positive melanocytes by significantly inhibiting cellular tyrosinase activity via binding to the free fatty acid receptor 2 (FFAR2). Moreover, 4 mM PA treatment did not alter melanocyte proliferation, indicating that it is an effective solution for hyperpigmentation, causing no cellular damage. The reduced DOPA-positive melanocytes and tyrosinase activity were also observed in mice ear skin tissue injected with a mixture of C. acnes and PF68, supporting that the inhibition of melanogenesis is likely to be mediated through fermentation metabolites from C. acnes fermentation using PF68 as a carbon source. Additionally, PA did not affect the growth of its parent bacteria C. acnes, hence is a potent fermentation metabolite that does not disrupt the balance of the skin microbiome.

Introduction Several reports have shown that neuromelanin-sensitive magnetic resonance imaging (NMI) using 3T magnetic resonance imaging is useful for the differential diagnosis of Parkinson's disease (PD), progressive supranuclear palsy (PSP), and other neurological diseases. However, the number of cases in previous studies has been insufficient. We aimed to determine the relationship between NMI and severity of PD and related disorders, and thereby establish the diagnostic utility of NMI for diagnosing neurological diseases. Methods We enrolled 591 patients (531 subjects after removal of duplicates) with parkinsonism who underwent NMI. The contrast ratio of the locus coeruleus (LC-CR) and the area of the substantia nigra pars compacta (SNc) were analyzed in each patient. Results The patients’ clinical diagnoses were as follows: 11 patients in the disease control group (DCG), 244 patients with PD, 49 patients with PSP, and 19 patients with multiple system atrophy with predominant parkinsonism. Additionally, some patients were diagnosed with dementia with Lewy bodies, vascular parkinsonism, and drug-induced parkinsonism. SNc in the patients with PD and PSP was significantly smaller than that in DCG. LC-CR in the patients with PD was lower than that in DCG; furthermore, LC-CR in the patients with PD was significantly lower than that in the patients with PSP. We found that an area under the receiver-operating characteristic curve, indicating diagnostic efficacy, of 0.85 for LC-CR is a promising biomarker for differentiating PD from PSP. Conclusion NMI effectively contributes to differentiating neurodegenerative diseases, such as PD and PSP.

SynopsisMelanins, the main pigments of the skin and hair in mammals, are synthesized within membrane-bound organelles of melanocytes called melanosomes. Melanosome structure and function are determined by a cohort of resident transmembrane proteins, many of which are expressed only in pigment cells and localize specifically to melanosomes. Defects in the genes that encode melanosome-specific proteins or components of the machinery required for their transport in and out of melanosomes underlie various forms of ocular or oculocutaneous albinism, characterized by hypopigmentation of the hair, skin, and eyes and by visual impairment. We review major components of melanosomes, including the enzymes that catalyze steps in melanin synthesis from tyrosine precursors, solute transporters that allow these enzymes to function, and structural proteins that underlie melanosome shape and melanin deposition. We then review the molecular mechanisms by which these components are biosynthetically delivered to newly forming melanosomes—many of which are shared by other cell types that generate cell type-specific lysosome-related organelles. We also highlight unanswered questions that need to be addressed by future investigation.

To investigate the role of platelet-rich plasma (PRP) from different sources in alleviating oxidative stress and ameliorating melanogenesis in UVB-irradiated PIG1 cells, PIG1 cells were irradiated with 80 mJ/cm2 UVB prior to 1% PRP application and the following experiments were taken: the viability of UVB-irradiated PIG1 cells, cellular malondialdehyde (MDA) and reactive oxygen species (ROS) content, and activities of antioxidant enzymes. Western blotting was utilized to detect the expression level of proteins associated with melanin synthesis, apoptosis, and DNA lesions. We found that PRP intervention promoted cell proliferation, reduced MDA and ROS content, increased the activities of series of antioxidant enzymes, and alleviated DNA damages in UVB-damaged PIG1 cells. It is important to note that PRP treatment inhibited UVB-induced melanogenesis via the PI3K/Akt/GSK3β signal pathway. Therefore, we suppose PRP treatment exerts a protective role through their antioxidation effect on UVB-damaged PIG1 cells and hinders melanogenesis induced by UVB irradiation.

PurposeTo investigate retinal sensitivity of highly myopic eyes without choroidal neovascularisation (CNV) or patchy chorioretinal atrophy (PCA) and investigated its association with anatomical characteristics including melanin distribution at the retinal pigment epithelium (RPE), which was evaluated with polarisation-sensitive optical coherence tomography (PS-OCT).DesignRetrospective consecutive observational cohort study.MethodsWe included highly myopic eyes (refractive error ≤−8.0 dioptres or axial length of ≥26.5 mm) from patients at the University of Tokyo Hospital. Retinal sensitivity was measured by microperimetry at 25 sectors within 6 degrees from the fovea. Depolarisation value, which reflected melanin pigmentation, was measured by a clinical prototype of PS-OCT and was parameterised as polarimetric entropy. Retinal sensitivity or entropy at the RPE in high myopia was compared with emmetropic control subjects. The association of retinal sensitivity with age, axial length, entropy, or choroidal thickness was assessed in per-eye and per-sector analysis.ResultsTwenty-three highly myopic eyes (age, 66.6±12.3 years) were included. The average retinal sensitivity was 25.3±3.0 dB, which was significantly decreased compared with the control (pConclusionsDecreased depolarisation at the RPE measured with PS-OCT, which reflected altered melanin pigmentation, was independently associated with reduced retinal sensitivity in patients with early stages of myopic maculopathy without CNV or PCA.

Oxidative stress parameters have been reported to be significantly higher than controls in diverse disorders of pigmentation but no such data seem to be extant for IGH.To verify whether heightened oxidative stress levels are seen in patients with IGH (compared with matched controls) and quantify the same in blood using appropriate biochemical markers. Further, an attempt to determine if there might be any correlation between the amount of oxidative stress and the severity of the disease.This prospective case-control study was conducted in Northern India. Thirty Indian patients (Fitzpatrick skin phototype (SPT) IV-V) were included. The diagnosis of IGH lesions was confirmed based on characteristic clinical, and dermoscopic characteristics and confirmed on histopathological examination (HE) of one of the lesions.The oxidative stress enzyme level was significantly higher among the cases compared to controls which were statistically significant (p 0.05). A positive correlation was also observed between the levels of these markers and number of lesions, but this finding was statistically not significant [p 0.05]. Assessment of melanin level by Dopa staining method in the IGH lesions revealed irregularly distributed melanin with areas of high and low melanin content and greater accumulation in the basement layer.The results of this probably the first study evaluating oxidative stress in IGH show that the oxidative stress is increased in patients with IGH. Level of oxidative stress seems to be correlated with both age of the patient (more in the elderly) and number of lesions.

Background Human skin, which is constantly exposed to solar ultraviolet radiation (UVR), has a unique ability to respond by increasing its pigmentation in a protective process driven by melanogenesis in human epidermal melanocytes (HEMs). However, the molecular mechanisms used by HEMs to detect and respond to UVR remain unclear. Objectives To investigate the function and potential mechanism of opsin 5 (OPN5), a photoreceptor responsive to UVR wavelengths, in melanogenesis in HEMs. Methods Melanin content in HEMs was determined using the NaOH method, and activity of tyrosinase (TYR) (a key enzyme in melanin synthesis) was determined by the l-DOPA method. OPN5 expression in UVR-treated vs. untreated HEMs and explant tissues was detected by reverse-transcription quantitative polymerase chain reaction (RT-qPCR), Western blotting and immunofluorescence. Short interfering RNA-mediated OPN5 knockdown and a lentivirus OPN5 overexpression model were used to examine their respective effects on TYR, tyrosinase-related protein 1 (TRP1), TRP2 and microphthalmia-associated transcription factor (MITF) expression, under UVR. Changes in expression of TYR, TRP1 and TRP2 caused by changes in OPN5 expression level were detected by RT-qPCR and Western blot. Furthermore, changes in signalling pathway proteins were assayed. Results We found that OPN5 is the key sensor in HEMs responsible for UVR-induced melanogenesis. OPN5-induced melanogenesis required Ca2+ -dependent G protein-coupled receptor- and protein kinase C signal transduction, thus contributing to the UVR-induced MITF response to mediate downstream cellular effects, and providing evidence of OPN5 function in mammalian phototransduction. Remarkably, OPN5 activation was necessary for UVR-induced increase in cellular melanin and has an inherent function in melanocyte melanogenesis. Conclusions Our results provide insight into the molecular mechanisms of UVR sensing and phototransduction in melanocytes, and may reveal molecular targets for preventing pigmentation or pigment diseases.

Tyrosinase is a key metalloenzyme for the biosynthesis of melanin that plays a critical role in the prevention of skin damage caused by ultraviolet (UV) radiation. However, the overproduction of melanin may cause a variety of skin diseases. Due to the toxicity and inefficiency of existing tyrosinase inhibitors, it is urgent to identify safe and potent alternatives from natural sources. Theaflavin, a single-component extracted from black tea, has been found to possess a variety of pharmacological activities. Herein, the inhibition kinetics of theaflavin on tyrosinase and inhibitory mechanism were determined using spectroscopy, molecular docking, and zebrafish model. The results showed that theaflavin inhibited the diphenolase activity of tyrosinase in a reversible mixed type manner with IC50 of 229.75 μmol/L and hindered the synthesis of melanin in zebrafish. This may be due to the formation of eight hydrogen bonds and hydrophobic effects between theaflavin and tyrosinase according to the results of molecular docking. To study the possible effects on the prevention of free radical-mediated skin cancer and photoaging caused by UV radiation, the antioxidation and UV filter properties of theaflavin were further verified. This study demonstrates that theaflavin is a potential multifunctional compound that can be used in cosmetic and medicinal products.

While eye drops are the most common ocular dosage form, eye drops for treating diseases of the posterior segment (retina, choroid, optic nerve) have yet to be developed. In glaucoma, eye drops are used extensively for delivering intraocular pressure (IOP) lowering medications to the anterior segment. However, degeneration of retinal ganglion cells (RGCs) in the retina may progress despite significant IOP lowering, suggesting that a complementary neuroprotective therapy would improve glaucoma management. Here, we describe a hypotonic, thermosensitive gel-forming eye drop for effective delivery of sunitinib, a protein kinase inhibitor with activity against the neuroprotective targets dual leucine zipper kinase (DLK) and leucine zipper kinase (LZK), to enhance survival of RGCs after optic nerve injury. Further, binding of sunitinib to melanin in the pigmented cells in the choroid and retinal pigment epithelium (RPE) led to prolonged intraocular residence time, including therapeutically relevant concentrations in the non-pigmented retinal tissue where the RGCs reside. The combination of enhanced intraocular absorption provided by the gel-forming eye drop vehicle and the intrinsic melanin binding properties of sunitinib led to significant protection of RGCs with only once weekly eye drop dosing. For a chronic disease such as glaucoma, an effective once weekly eye drop for neuroprotection could result in greater patient adherence, and thus, greater disease management and improved patient quality of life.

Molecular mechanisms of uveal melanoma development in association with high pigmentation are unclear. Tyrosinase Related Protein (TYRP1) is not only one of the important melanogenesis marker that contributes to melanin synthesis, but can also prevents the melanocyte death. The induction of melanogenesis leads to induction of HIF-1α which can affect the behavior of melanoma cells and its surrounding environment. The aim of our study was to determine the expression of TYRP1 and HIF-1α at the protein and RNA level and determine its prognostic significance. In the present study, the expression of TYRP1 and HIF-1α was investigated on 61 formalin-fixed paraffin-embedded choroidal melanoma samples by immunohistochemistry. Fresh 50 samples were validated by real-time PCR. Results were correlated with clinicopathological parameters and Kaplan–Meier was performed to determine the prognostic significance. High immunoexpression of TYRP1 and HIF-1α was present in 61 and 54% of patients, respectively. Both TYRP1 and HIF-1α correlated well with high pigmentation and BAP1 (BRCA1 Associated Protein-1) loss (p

Previous pathologic studies evaluated the substantia nigra pars compacta (SNpc) of a limited number of idiopathic Parkinson's disease (IPD) patients with relatively longer disease durations. Therefore, it remains unknown which region of the SNpc is most significantly affected in early‐stage IPD. We hypothesized that a voxelwise analysis of thin‐section neuromelanin‐sensitive MRI (NM‐MRI) may help determine the significantly affected regions of the SNpc in early‐stage IPD and localize these areas in each nigrosome on high‐spatial‐resolution susceptibility map‐weighted imaging (SMwI). Ninety‐six healthy subjects and 50 early‐stage IPD patients underwent both a 0.8 × 0.8 × 0.8 mm3 NM‐MRI and a 0.5 × 0.5 × 1.0 mm3 multi‐echo gradient‐recalled echo imaging for SMwI. Both NM‐MRI and SMwI templates were created by using image data from the 96 healthy subjects. Permutation‐based nonparametric tests were conducted to investigate spatial differences between the two groups in NM‐MRI, and the results were displayed on both NM‐MRI and SMwI templates. The posterolateral and anteromedial regions of the SNpc in NM‐MRI were significantly different between the two groups, corresponding to the nigrosome 1 and nigrosome 2 regions, respectively, on the SMwI template. There were the areas of significant spatial difference in the hypointense SN on SMwI between early‐stage IPD patients and healthy subjects. These areas on SMwI were slightly greater than those on NM‐MRI, including the areas showing group difference on NM‐MRI. Our voxelwise analysis of NM‐MRI suggests that two regions (nigrosome 1 and nigrosome 2) of the SNpc are separately affected in early‐stage IPD., Ninety‐six healthy subjects and 50 early‐stage IPD patients underwent both a 0.8 × 0.8 × 0.8 mm3 NM‐MRI and a 0.5 × 0.5 × 1.0 mm3 multi‐echo gradient‐recalled echo imaging for SMwI. Using both NM‐MRI and SMwI templates, we conducted voxelwise analysis of NM‐MRI between healthy subjects and IPD patients, and found that two regions (nigrosome 1 and nigrosome 2) of the substantia nigra pars compacta are separately affected in early‐stage IPD.

Islet transplantation is currently a promising treatment for type 1 diabetes mellitus. However, the foreign body reaction and retrieval difficulty often lead to transplantation failure and hinder the clinical application. To address these two challenges, we propose a balanced charged sodium alginate-polyethyleneimine-melanin (SA-PEI-Melanin) threadlike hydrogel with immune shielding and retrievable properties. The attractiveness of this study lies in that the introduction of melanin can stimulate insulin secretion, especially under near-infrared (NIR) irradiation. After demonstrating a good immune-shielding effect, we performed an in vivo transplantation experiment. The results showed that the blood glucose level in the SA-PEI-Melanin group was stably controlled below the diabetic blood glucose criterion, and this blood glucose level could be further adjusted after NIR irradiation. In addition, the evaluation after retrieving the SA-PEI-Melanin hydrogel indicated that the islets still maintained a normal physiological function, further proving its excellent immunological protection. This study provides a new approach for the accurate regulation of blood glucose in patients with type 1 diabetes mellitus and contributes to developing a promising transplant system to reconcile real-time and precise light-defined insulin secretion regulation.

Pigmentation, a process controlled by melanogenesis, plays a vital role in protecting the skin against harmful ultraviolet rays. The level of protection is compromised in case of hypopigmentation. This study aimed to evaluate an Aspalathus linearis extract, fractions and phytoconstituents, for their efficacy on melanogenesis stimulation. Fifteen compounds were kinetically assessed against tyrosinase; the rate-limiting enzyme of melanogenesis. Aspalathin and catechin significantly (p value A. linearis’ compounds on skin re-pigmentation.

Maria Grazia Ferraro,1 Marialuisa Piccolo,1 Alessandro Pezzella,2 Fabrizia Guerra,1 Francesco Maione,1 Gian Carlo Tenore,1 Rita Santamaria,1 Carlo Irace,1 Ettore Novellino1 1Department of Pharmacy, School of Medicine and Surgery, University of Naples “Federico II”, Naples, 80131, Italy; 2Department of Chemical Sciences, University of Naples “Federico II”, Naples, 80126, ItalyCorrespondence: Carlo Irace;Rita SantamariaDepartment of Pharmacy, School of Medicine and Surgery, University of Naples “Federico II”, Via D. Montesano 49, Naples, 80131, ItalyTel +39 081 678416; +39 081 678421Fax +39 081 678403Email carlo.irace@unina.it; rita.santamaria@unina.itIntroduction: Melanocytes are engaged in synthesis, transport, and release of pigments at the epidermal-melanin units in response to the finely regulated melanogenic pathway. A multifaceted combination of both intrinsic and extrinsic factors – from endocrine and paracrine dynamics to exogenous stimuli such as sunlight and xenobiotics – modulates expression and activity of proteins involved in pigmentation, including the rate-limiting enzyme tyrosinase. As well as playing critical physiological functions comprising skin photoprotection, melanins define hair and skin pigmentation which in turn have impacted considerably to human social communication since time immemorial. Additionally, numerous skin diseases based on pigmentation alterations can have serious public influence. While several melanogenesis inhibitors are already available, the number of melanin activators and tyrosinase stimulators as drug-like agents is still limited.Methods: To explore the biological effects of an Annurca Apple-based nutraceutical preparation (AMS) on melanin production, experiments in cellular models of human skin were performed. Both primary cultures and co-cultures of epidermal melanocytes (HEMa) and follicular keratinocytes (HHFK) were used.Results: We show that AMS, by now branded for its cutaneous beneficial effects, induces in total biocompatibility a significant promelanogenic effect in human primary melanocytes. In line, we found melanin cytosolic accumulation consistent with tyrosinase up-regulation.Conclusion: Disposal of skin pigmenting agents would be attractive for the treatment of hypopigmentation disorders, to postpone skin photoaging or simply for fashion, so that discovery and development of melanogenesis stimulators, especially from natural sources, is nowadays a dynamic area of research.Keywords: melanins, skin pigmentation, tyrosinase, skin pigmenting agents, natural bioactive molecules

Previous studies have used subjective assessments to implicate darker skin color as a risk factor for glaucoma. This study used objective measurements to determine whether skin melanin is a risk fa...

Cutaneous melanoma tumors are heterogeneous and show diverse responses to treatment. Identification of robust molecular biomarkers for classifying melanoma tumors into clinically distinct and homogenous subtypes is crucial for improving the diagnosis and treatment of the disease. In this study, we present a classification of melanoma tumors into four subtypes with different survival profiles based on three distinct gene expression signatures: keratin, immune, and melanogenesis. The melanogenesis expression pattern includes several genes that are characteristic of the melanosome organelle and correlates with worse survival, suggesting the involvement of melanosomes in melanoma aggression. We experimentally validated the secretion of melanosomes into surrounding tissues by melanoma tumors, which potentially affects the lethality of metastasis. We propose a simple molecular decision tree classifier for predicting a tumor’s subtype based on representative genes from the three identified signatures. Key predictor genes were experimentally validated on melanoma samples taken from patients with varying survival outcomes. Our three-pattern approach for classifying melanoma tumors can contribute to advancing the understanding of melanoma variability and promote accurate diagnosis, prognostication, and treatment.

Neuromelanin (NM) is a dark pigment that mainly exists in neurons of the substantia nigra pars compacta (SNc). In Parkinson disease (PD) patients, NM concentration decreases gradually with degeneration and necrosis of dopamine neurons, suggesting potential use as a PD biomarker. We aimed to evaluate associations between NM concentration in in vivo SN and PD progression and different motor subtypes using NM magnetic resonance imaging (NM-MRI). Fifty-four patients with idiopathic PD were enrolled. Patients were divided into groups by subtypes with different clinical symptoms: tremor dominant (TD) group and postural instability and gait difficulty (PIGD) group. Fifteen healthy age-matched volunteers were enrolled as controls. All subjects underwent clinical assessment and NM-MRI examination. PD patients showed significantly decreased contrast-to-noise ratio (CNR) values in medial and lateral SN (P P = 0.001). PIGD patients showed significant decreases in CNR mean values in lateral SN compared to TD patients (P = 0.004). Diagnostic accuracy of using lateral substantia nigra (SN) in TD and PIGD groups was 79% (sensitivity 76.5%, specificity 78.6%). NM concentration in PD patients decreases gradually during disease progression and differs significantly between PD subtypes. NM may be a reliable biomarker for PD severity and subtype identification.

Background Melanin is synthesized in melanocytes and transferred to keratinocytes through dendrites. Endogenous pyruvate is a key metabolite for ATP production in glycolysis, and the tricarboxylic acid (TCA) cycle and exogenous pyruvate provide protection against oxidative stress and acidosis in the intercellular space. The function of pyruvate in the regulation of dendrite outgrowth remains to be elucidated. Objective We examined the effect of pyruvate on dendritic elongation and skin pigmentation Methods Murine B16F10 melanoma cells and human primary melanocytes were used for in vitro analysis. Melanin quantitation and histochemical staining were performed in a 3D pigmented human skin model. Results We demonstrated the participation of monocarboxylate transporters (MCTs) responsible for the membrane transport of pyruvate in B16F10 melanoma cells. The accumulation of pyruvate occurred in a pH-dependent manner, which was highly sensitive to a specific MCT inhibitor (α-cyano-4-hydroxycinnamic acid). α-MSH-induced morphological changes, including dendrite elongation and growth-cone-like structure, were diminished in B16F10 cells upon treatment with pyruvate. In addition, the number of dendrite branches was reduced in normal human epidermal melanocytes. As the Rho-subfamily of monomeric GTP-binding proteins modulates dendrite formation, we subsequently examined the suppression of Rac1 activation by pyruvate, but not RhoA and Cdc42. Furthermore, pyruvate showed anti-melanogenic effects against UV-induced pigmentation in reconstructed pigmented epidermis, established by co-seeding autologous melanocytes and keratinocytes, which act similar to in vivo skin tissue. Conclusion These results suggest that pyruvate treatment may be an alternative or additive therapeutic strategy to prevent hyperpigmentation.

Introduction Parkinson's disease (PD) is the second most common neurodegenerative disease. However, the rate of misdiagnosis remains high, even at specialized movement disorder centers. Purpose To assess the accuracy of nigrosome 1 and midbrain neuromelanin evaluation in the diagnosis of PD, and to identify possible differences in diagnostic accuracy between neuroradiologists of different experience levels in analyzing these structures. Methods A case-control study was conducted between April 2017 and January 2019. We prospectively evaluated 41 PD patients and 21 control individuals. Participants underwent axial, T2*-weighted, multi-echo gradient echo (GRE), and susceptibility-weighted imaging phase (SWIp) magnetic resonance imaging (MRI) sequences to evaluate nigrosome 1 and axial, T1-weighted, turbo spin-echo magnetization transfer contrast (MTC) MRI sequences to evaluate midbrain neuromelanin. All MRI sequences were acquired at 3.0 T. The images were analyzed by two experienced neuroradiologists, one with and one without expertise in nigrosome 1 and neuromelanin imaging. The sensitivity, specificity, and accuracy of the diagnoses were calculated between PD patients vs. healthy participants and between the two neuroradiologists. Results The sensitivity and specificity of each imaging sequence for PD diagnosis were as follows: multi-echo, 100% and 86%; SWIp, 91% and 88%; and T1 MTC, 90% and 93%, respectively. The accuracy of clinical PD diagnosis was higher for the expert neuroradiologist compared to the neuroradiologist lacking expertise. Conclusion Nigrosome 1 and midbrain neuromelanin represent useful tools for PD diagnosis. However, these structures should be evaluated by experienced neuroradiologists in order to ensure high accuracy and reproducibility.

Multiple sequential actions, performed during parental behaviors, are essential elements of reproduction in mammalian species. We showed that neurons expressing melanin concentrating hormone (MCH) in the lateral hypothalamic area (LHA) are more active in rodents of both sexes when exhibiting parental nursing behavior. Genetic ablation of the LHA-MCH neurons impaired maternal nursing. The post-birth survival rate was lower in pups born to female mice with congenitally ablated MCH neurons under control of tet-off system, exhibiting reduced crouching behavior. Virgin female and male mice with ablated MCH neurons were less interested in pups and maternal care. Chemogenetic and optogenetic stimulation of LHA-MCH neurons induced parental nursing in virgin female and male mice. LHA-MCH GABAergic neurons project fibres to the paraventricular hypothalamic nucleus (PVN) neurons. Optogenetic stimulation of PVN induces nursing crouching behavior along with increasing plasma oxytocin levels. The hypothalamic MCH neural relays play important functional roles in parental nursing behavior in female and male mice.

Melanocytes are static, minimally proliferative cells. This leaves them vulnerable in vitiligo. Yet upon malignant transformation, they form vicious tumors. This profound switch in physiology is accompanied by genetic change and is driven by environmental factors. If UV exposure in younger years supports malignant transformation and melanoma formation, it can likewise impart mutations on melanocytes that reduce their viability, to initiate vitiligo. A wide variety of microbes can influence these diametrically opposed outcomes before either disease takes hold. These microbes are vehicles of change that we are only beginning to study. Once a genetic modification occurs, there is a wide variety of immune cells ready to respond. Though it does not act alone, the T cell is among the most decisive responders in this process. The same biochemical process that offered the skin protection by producing melanin can become an Achilles heel for the cell when the T cells target melanosomal enzymes or, on occasion, neoantigens. T cells are precise, determined, and consequential when they strike. Here, we probe the relationship between the microbiome and its metabolites, epithelial integrity, and the activation of T cells that target benign and malignant melanocytes in vitiligo and melanoma.

International audience; Introduction: Unlike "light" cylobutane pyrimidine dimers (CPD) formed during ultraviolet radiation (UVR) exposure, dark CPD (dCPD) are formed afterwards. Studies have attributed this to delayed melanin sensitization. There are no data on the role of melanin in dCPD formation in human skin.Methods and results: Volunteers of Fitzpatrick skin types (FST I/II vs. VI) were exposed to erythemally equivalent doses of solar simulated radiation. CPD were assessed by semi-quantitative immunostaining in whole epidermis and in three epidermal zones, and quantitative HPLC-MS/MS (whole epidermis) at different times post-exposure up to 24 hr. A CPD peak that appeared at 1-2 hr post-exposure in whole epidermis measurements, in all skin types, demonstrated dCPD. However, both dCPD and light CPD were absent in the basal layer of FST VI with the greatest melanin concentration. Modelling the whole epidermis data showed no differences between the repair kinetics of FST I/II and VI.Discussion: Melanin may be a sensitizer or "sunscreen" for dCPD depending on its location and concentration. Previous CPD repair studies in human skin have assumed peak CPD immediately after UVR exposure and so have overestimated total repair.

Background Melanonychia refers to brown-black color pigmentation due to melanin or not-melanin deposition in the nail plate. Onychoscopy allows to distinguish if the pigmentation is due by melanin or not. The main causes of non-melanic pigmentation are subungual hematoma and pigmented onychomycosis. Fungal melanonychia (FM), is rare and may present as diffuse or longitudinal pigmentation. Differential diagnosis includes melanic activation, such as ethnic-type nail pigmentation or frictional melanonychia, but also versus melanic proliferation, such as nevus or nail melanoma. Fungal melanonychia can be due a colonization by fungi with black variant or by melanin activation due to inflammation of fungal invasion. Objectives The aim of paper is to increase clinical and dermoscopic knowledge of this increasingly frequent disease. Methods In this retrospective observational study, twenty patients with dermatophytic melanonychia were collected, with available clinical and dermoscopic pictures. The diagnosis of dermatophytic melanonychia was made based on clinical manifestation and mycological examination. KOH smear was performed in all cases. For each patient, clinical data included: age, gender, type of melanonychia and involved fingers. Results This study aimed to show increased incidence of dermatophytic melanonychia and its correct management. In addition, we reviewed our collected cases and described the clinical and dermoscopic features of dermatophytic melanonychia. Conclusions The results of this study showed that physicians should keep in mind the diagnosis of this increasing disease, and that it cannot be performed relying only on clinical grounds. We would like to highlight the importance of tools as KOH examination, culture, and dermoscopy.

Oligonucleotide-based materials such as spherical nucleic acid (SNA) have been reported to exhibit improved penetration through the epidermis and the dermis of the skin upon topical application. Herein, we report a self-assembled, skin-depigmenting SNA structure, which is based upon a bifunctional oligonucleotide amphiphile containing an antisense oligonucleotide and a tyrosinase inhibitor prodrug. The two components work synergistically to increase oligonucleotide cellular uptake, enhance drug solubility, and promote skin penetration. The particles were shown to reduce melanin content in B16F10 melanoma cells and exhibited a potent antimelanogenic effect in an ultraviolet B-induced hyperpigmentation mouse model.

Preclinical studies have implicated noradrenergic (NA) dysfunction in cocaine addiction. In particular, the NA system plays a central role in motivated behavior and may partake in the regulation of craving and drug use. Yet, human studies of the NA system are scarce, likely hampered by the difficulty in precisely localizing the locus coeruleus (LC). Here, we used neuromelanin imaging to localize the LC and quantified LC neuromelanin signal (NMS) intensity in 44 current cocaine users (CU; 37 men) and 59 nondrug users (NU; 44 men). We also employed fMRI to investigate cue-induced regional responses and LC functional connectivities, as quantified by generalized psychophysiological interaction (gPPI), in CU. Imaging data were processed by published routines and the findings were evaluated with a corrected threshold. We examined how these neural measures were associated with chronic cocaine craving, as assessed by the Cocaine Craving Questionnaire (CCQ). Compared to NU, CU demonstrated higher LC NMS for all probabilistic thresholds defined of 50–90% of the peak. In contrast, NMS of the ventral tegmental area/substantia nigra (VTA/SN) did not show significant group differences. Drug as compared to neutral cues elicited higher activations of many cortical and subcortical regions, none of which were significantly correlated with CCQ score. Drug vs. neutral cues also elicited “deactivation” of bilateral parahippocampal gyri (PHG) and PHG gPPI with a wide array of cortical and subcortical regions, including the ventral striatum and, with small volume correction, the LC. Less deactivation of the PHG (r = 0.40, p = 0.008) and higher PHG-LC gPPI (r = 0.44, p = 0.003) were positively correlated with the CCQ score. In contrast, PHG-VTA/SN connectivity did not correlate with the CCQ score. Together, chronic cocaine exposure may induce higher NMS intensity, suggesting neurotoxic effects on the LC. The correlation of cue-elicited PHG LC connectivity with CCQ score suggests a noradrenergic correlate of chronic cocaine craving. Potentially compensating for memory functions as in neurodegenerative conditions, cue-elicited PHG LC circuit connectivity plays an ill-adaptive role in supporting cocaine craving.

Vitiligo is autoimmune, acquired, idiopathic, chronic, and progressive de/hypopigmentary cutaneous condition that targets the cell-producing pigment called melanin. It binds to a thread of great disappointment and emotional stress in societies. Combining multiple stress-related theories like toxic compound accumulation, autoimmunity, mutations, altered cellular environment, infection, impaired migration/proliferation, and immunological mismatch of anti-melanocyte and self-reactive T-cells that cause melanocytes damage is formulated resulting in vitiligo. Vitiligo has an orphan status for drug synthesis. Still, different therapies are available, with topical steroids and narrow-band ultraviolet-B monotherapy being the most common treatments, others including medical, physical, or surgical, but not effective. Each modality has its baggage of disadvantages and side effects. Stimulation of the transcriptional process for melanogenesis is mainly achieved by the cAMP-dependent activation of several melanogenic genes by MITF. In this review, we summarized that cAMP encourages the expression of the enzyme tyrosinase, TYRP1, TYRP2, and most other biological effects of cAMP are mediated through the cAMP-dependent PKA pathway resulting in CREB phosphorylation. It has been shown that TYRP1 and 2 do not have cAMP response elements (CREs) in promoting regions; the regulation of these genes by cAMP occurs through the direct participation of MITF during melanogenesis. The available medicines, therefore, only provide symptomatic relief, but do not stop the disease progression. In addition, the treatment process needs to be changed; existing approaches need to be overlooked for patients who are suffering and therefore analyze its efficacy and safety to achieve a favorable risk-benefit ratio.