Explore the vast range of titles available.

Skin color diversity is the most variable and noticeable phenotypic trait in humans resulting from constitutive pigmentation variability. This paper will review the characterization of skin pigmentation diversity with a focus on the most recent data on the genetic basis of skin pigmentation, and the various methodologies for skin color assessment. Then, melanocyte activity and amount, type and distribution of melanins, which are the main drivers for skin pigmentation, are described. Paracrine regulators of melanocyte microenvironment are also discussed. Skin response to sun exposure is also highly dependent on color diversity. Thus, sensitivity to solar wavelengths is examined in terms of acute effects such as sunburn/erythema or induced-pigmentation but also long-term consequences such as skin cancers, photoageing and pigmentary disorders. More pronounced sun-sensitivity in lighter or darker skin types depending on the detrimental effects and involved wavelengths is reviewed.

As a main part of pigmentation disorders, skin depigmentation diseases such as vitiligo and achromic naevus are very common and get more attention now. The pathogenesis of depigmentation includes melanocyte dysfunction and loss, which are possibly caused by heredity, autoimmunity and oxidative stress. Among them, oxidative stress plays a key role; however, few clinical treatments can deal with oxidative stress. As reported, Cistanche deserticola polysaccharide (CDP) is an effective antioxidant; based on that, we evaluated its role in melanocyte and further revealed the mechanisms. In this study, we found that CDP could promote melanogenesis in human epidermal melanocytes (HEMs) and mouse melanoma B16F10 cells, it also induced pigmentation in zebrafish. Furthermore, CDP could activate mitogen‐activated protein kinase (MAPK) signal pathway, then up‐regulated the expression of microphthalmia‐associated transcription factor (MITF) and downstream genes TYR, TRP1, TRP2 and RAB27A. Otherwise, we found that CDP could attenuate H2O2‐induced cytotoxicity and apoptosis in melanocytes. Further evidence revealed that CDP could enhance NRF2/HO‐1 antioxidant pathway and scavenge intracellular ROS. In summary, CDP can promote melanogenesis and prevent melanocytes from oxidative stress injury, suggesting that CDP helps maintain the normal status of melanocytes. Thus, CDP may be a novel drug for the treatment of depigmentation diseases. Cistanche deserticola polysaccharide (CDP) promotes melanogenesis in human epidermal melanocytes via activating mitogen‐activated protein kinase (MAPK) signal pathway, then up‐regulates the expression of MITF, TYR, TRP1, TRP2, and RAB27A. Otherwise, CDP can attenuate H2O2‐induced oxidative stress in melanocytes via enhancing NRF2/HO‐1 antioxidant pathway and scavenge intracellular ROS.

Melanogenesis is the biological and biochemical process of melanin and melanosome biosynthesis. Melanin is formed by enzymic reactions of tyrosinase family proteins that convert tyrosine to form brown-black eumelanin and yellow-red pheomelanin within melanosomal compartments in melanocytes, following the cascades of events interacting with a series of autocrine and paracrine signals. Fully melanized melanosomes are delivered to keratinocytes of the skin and hair. The symbiotic relation of a melanocyte and an associated pool of keratinocytes is called epidermal melanin unit (EMU). Microphthalmia-associated transcription factor (MITF) plays a vital role in melanocyte development and differentiation. MITF regulates expression of numerous pigmentation genes for promoting melanocyte differentiation, as well as fundamental genes for maintaining cell homeostasis. Diseases involving alterations of EMU show various forms of pigmentation phenotypes. This review introduces four major topics of melanogenesis cascade that include (1) melanocyte development and differentiation, (2) melanogenesis and intracellular trafficking for melanosome biosynthesis, (3) melanin pigmentation and pigment-type switching, and (4) development of a novel therapeutic approach for malignant melanoma by elucidation of melanogenesis cascade.

Training of neural networks for automated diagnosis of pigmented skin lesions is hampered by the small size and lack of diversity of available datasets of dermatoscopic images. We tackle this problem by releasing the HAM10000 (\"Human Against Machine with 10000 training images\") dataset. We collected dermatoscopic images from different populations acquired and stored by different modalities. Given this diversity we had to apply different acquisition and cleaning methods and developed semi-automatic workflows utilizing specifically trained neural networks. The final dataset consists of 10015 dermatoscopic images which are released as a training set for academic machine learning purposes and are publicly available through the ISIC archive. This benchmark dataset can be used for machine learning and for comparisons with human experts. Cases include a representative collection of all important diagnostic categories in the realm of pigmented lesions. More than 50% of lesions have been confirmed by pathology, while the ground truth for the rest of the cases was either follow-up, expert consensus, or confirmation by in-vivo confocal microscopy.

The skin of an organism is affected by various environmental factors and fights against aging stress via mechanical and biochemical responses. Photoaging induced by ultraviolet B (UVB) irradiation is common and is the most vital factor in the senescence phenotype of skin, and so, suppression of UVB stress-induced damage is critical. To lessen the UVB-induced hyperimmune response and hyperpigmentation, we investigated the ameliorative effects of intense pulsed light (IPL) treatment on the photoaged phenotype of skin cells. Normal human epidermal keratinocytes and human epidermal melanocytes were exposed to 20 mJ/cm2 of UVB. After UVB irradiation, the cells were treated with green (525–530 nm) and yellow (585–592 nm) IPL at various time points prior to the harvest step. Subsequently, various signs of excessive immune response, including expression of proinflammatory and melanogenic genes and proteins, cellular oxidative stress level, and antioxidative enzyme activity, were examined. We found that IPL treatment reduced excessive cutaneous immune reactions by suppressing UVB-induced proinflammatory cytokine expression. IPL treatment prevented hyperpigmentation, and combined treatment with green and yellow IPL synergistically attenuated both processes. IPL treatment may exert protective effects against UVB injury in skin cells by attenuating inflammatory cytokine and melanogenic gene overexpression, possibly by reducing intracellular oxidative stress. IPL treatment also preserves antioxidative enzyme activity under UVB irradiation. This study suggests that IPL treatment is a useful strategy against photoaging, and provides evidence supporting clinical approaches with non-invasive light therapy.

While natural products and synthetic chemicals are used in functional cosmetics, their potential side effects remain a concern. This has driven the need for safer and more effective agents to treat skin disorders. This has driven the need safer and more effective agents to treat skin disorders. Therefore, the present study aimed to explore the functional properties of Cannabis sativa stem-derived nanoparticles (CSS-NPs) and evaluate their potential as a cosmetic ingredient. Using nanoparticle analysis, CSS-NPs, with a mean diameter of ~120 nm exhibited notable resistance to external stress conditions, including pH fluctuation and enzymatic degradation by DNase, RNase and proteinase K. They also contained 48 distinct biochemical components. In vitro assays revealed that CSS-NPs significantly downregulated the expression of genes and proteins associated with melanin synthesis in mouse B16F10 melanoma cells under α-melanocyte stimulating hormone (α-MSH)-induced hyperpigmentation. These inhibitory effects were mediated by the activation of ERK and Akt signaling pathways. Furthermore, CSS-NPs improved the viability of α-MSH-treated B16F10 cells; this was accompanied by the upregulation of antioxidant-associated enzymes and a decrease in α-MSH-induced reactive oxygen species levels. Collectively, these findings suggested that CSS-NPs carry out a key role in mitigating skin pigmentation and enhancing antioxidant defenses by modulating the ERK/Akt axis during excessive melanin synthesis. Thus, CSS-NPs represent a promising multifunctional cosmetic ingredient with potential in treating pigmentation disorders and protecting skin cells.

The causative mechanism for the immunodeficiency and autoinflammatory disease XLPDR is unknown. Burstein and colleagues show that XLPDR is caused by disruption of POLA1 , which encodes a DNA polymerase subunit; this, in turn, leads to dysregulated production of type I interferons. Aberrant nucleic acids generated during viral replication are the main trigger for antiviral immunity, and mutations that disrupt nucleic acid metabolism can lead to autoinflammatory disorders. Here we investigated the etiology of X-linked reticulate pigmentary disorder (XLPDR), a primary immunodeficiency with autoinflammatory features. We discovered that XLPDR is caused by an intronic mutation that disrupts the expression of POLA1 , which encodes the catalytic subunit of DNA polymerase-α. Unexpectedly, POLA1 deficiency resulted in increased production of type I interferons. This enzyme is necessary for the synthesis of RNA:DNA primers during DNA replication and, strikingly, we found that POLA1 is also required for the synthesis of cytosolic RNA:DNA, which directly modulates interferon activation. Together this work identifies POLA1 as a critical regulator of the type I interferon response.

Pigmented dermatoses are skin diseases characterized by pigmentation changes in the skin's surface due to abnormal melanocyte production. Photon-skin-rejuvenation technology can be effective for the management of facial pigmented dermatoses. Black Gold Delicate Pulse Light (DPL) Super Photon Skin Rejuvenation therapy is a new technology based on traditional photo rejuvenation. The study intended to evaluate the therapeutic efficacy of DPL therapy in the management of targeted pigmented skin diseases, such as melasma, solar lentigines, and postinflammatory hyperpigmentation. The research team conducted a prospective cohort study. The study took place at Department of Dermatology, Affiliated Hospital of Shaoxing University, Shaoxing, China. Participants were 130 patients with facial pigmented dermatoses treated at the hospital between February 2021 and December 2021. The research team assigned participants to one of two groups, with 65 participants in each group: (1) the control group, the intense pulsed light (IPL) group, who received IPL treatment, and (2) the intervention group, the DPL group, who received black gold DPL super photon skin rejuvenation. Both groups received the treatments once a month for 6 months. At baseline and postintervention for both groups, the research team: (1) collected 5 ml of fasting venous blood from participants and measured serum concentrations of melatonin (MEL), vascular endothelial growth factor (VEGF) and endothelin-1 (ET-1) using enzyme-linked immunosorbent assay (ELISA); (2) assessed the degree of reduction of facial pigmentation using the Visia skin test and each participant's clinical results and calculated total efficacy; and (3) monitored and recorded adverse events. Compared to the IPL group, the DPL group: (1) had greater symptom mitigation of the facial pigmented dermatosis, as evinced by significantly lower serum MEL (P = .001) and ET-1 (P = .020) concentrations and higher VEGF levels (P = .001); (2) for participants with freckles (P = .045), cafe-au-lait spots (P = .021), or post-acne hyperpigmentation (P = .029), had a significantly higher total efficacy; and (3) had a lower incidence of adverse events (P = .041). Black Gold DPL Super Photon Skin Rejuvenation offers a significantly higher safety profile and treatment efficacy for pigmented-skin diseases compared to IPL treatment. These promising results suggest potential for its use in clinical practice, but clinical adoption requires future trials.

Worldwide, congenital deafness and pigmentation disorders impact millions with their diverse manifestations, and among these genetic conditions, mutations in the Microphthalmia-associated transcription factor ( MITF : OMIM#156845) gene are notable for their profound effects on melanocyte development and auditory functions. This study reports a novel porcupine model exhibiting spontaneous deafness and pigmentation abnormalities reminiscent of human Waardenburg Syndrome Type 2 (WS2: OMIM#193510). Through phenotypic characterization, including coat color, skin, eye morphology, and auditory brainstem response (ABR) assessments, we identified hypopigmentation and complete deafness in mutant porcupines. To pinpoint the genetic basis, a breeding program was established, and Bulk Segregant Analysis (BSA) combined with RNA sequencing was conducted. Primers based on the identified candidate genes were designed for PCR amplification, followed by verification through Sanger sequencing. Through BSA analysis, we identified a total of 88 SNP and 336 InDel candidate sites. By annotating the Mitf gene, we obtained four unique transcript sequences. The SNP and InDel sites within the porcupine Mitf gene sequence, identified through BSA screening, were analyzed in conjunction with the gene’s annotation results. This analysis revealed a specific mutation site, Mitf c.875_877delGAA p. (Arg217del), which was subsequently verified by Sanger sequencing. This naturally occurring Mitf mutation in porcupines provides a valuable model for studying the mechanisms underlying WS2 and exploring potential therapeutic strategies for deafness and pigmentation-related disorders.

Dyschromatosis universalis hereditaria (DUH) is a pigmentary genodermatosis characterized by a mixture of hyperpigmented and hypopigmented macules distributed randomly over the body. No causative genes have been reported to date. In this study, we investigated a large five-generation Chinese family with DUH. After excluding the two known DUH loci, we performed genome-wide linkage analysis and identified a DUH locus on chromosome 2q33.3-q36.1 with a maximum LOD score of 3.49 with marker D2S2382. Exome sequencing identified a c.1067T>C (p.Leu356Pro) mutation in exon 3 of ABCB6 (ATP-binding cassette subfamily B, member 6) in the DUH family. Two additional missense mutations, c.508A>G (p.Ser170Gly) in exon 1 and c.1736G>A (p.Gly579Glu) in exon 12 of ABCB6, were found in two out of six patients by mutational screening using sporadic DUH patients. Immunohistologic examination in biopsy specimens showed that ABCB6 is expressed in the epidermis and had a diffuse cytoplasmic distribution. Examination of subcellular localization of wild-type ABCB6 in a B16 mouse melanoma cell line revealed that it is localized to the endosome-like compartment and dendrite tips, whereas disease-causing mutations of ABCB6 resulted in its retention in the Golgi apparatus. Our studies identified ABCB6 as the first pathogenic gene associated with DUH. These findings suggest that ABCB6 may be a physiological factor for skin pigmentation.