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Melanin degradation

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https://www.readbyqxmd.com/read/29956303/an-explanation-for-the-mysterious-distribution-of-melanin-in-human-skin-a-rare-example-of-asymmetric-melanin-organelle-distribution-during-mitosis-of-basal-layer-progenitor-keratinocytes
#1
N Joly-Tonetti, J I D Wibawa, M Bell, D J Tobin
BACKGROUND: Melanin is synthesized by melanocytes in the basal layer of the epidermis. When transferred to surrounding keratinocytes it is the key UVR-protective biopolymer responsible for skin pigmentation. Most melanin is observable in the proliferative basal layer of the epidermis, and only sparsely distributed in the stratifying/differentiating epidermis. The latter has been explained, despite formal evidence, to 'melanin degradation' in supra-basal layers. OBJECTIVES: Our aim was to re-evaluate this currently-accepted basis for melanin distribution in the human skin epidermis, and whether this pattern is altered after a regenerative stimulus...
June 29, 2018: British Journal of Dermatology
https://www.readbyqxmd.com/read/29890139/anti-melanogenic-activity-of-schaftoside-in-rhizoma-arisaematis-by-increasing-autophagy-in-b16f1-cells
#2
Pan Soo Kim, Ji Hyun Shin, Doo Sin Jo, Dong Woon Shin, Dong-Hwa Choi, Woo Jung Kim, Kyuhee Park, Jin Kyu Kim, Chul Gue Joo, Jong Suk Lee, Yongmun Choi, Yong Won Shin, Joong Jin Shin, Hong Bae Jeon, Jin-Ho Seo, Dong-Hyung Cho
Skin pigmentation involves multiple processes, including melanin synthesis, transport, and melanosome release. Melanin content determines skin color and protects against UV radiation-induced damage. Autophagy is a cooperative process between autophagosomes and lysosomes that degrades cellular components and organelles. In the present study, B16F1 cells were treated with Rhizoma Arisaematis extract (RA) and assessed for pigmentation and autophagy regulation. RA treatment suppressed the α-MSH-stimulated increase of melanogenesis and down-regulated the expression of tyrosinase and TRP1 proteins in B16F1 cells...
June 14, 2018: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/29803170/sargaquinoic-acid-ameliorates-hyperpigmentation-through-camp-and-erk-mediated-downregulation-of-mitf-in-%C3%AE-msh-stimulated-b16f10-cells
#3
Mohammed Shariful Azam, Misung Kwon, Jinkyung Choi, Hyeung-Rak Kim
Hyperpigmentation disorders of the skin adversely influence the quality of life. We previously demonstrated the hypopigmenting properties of the ethanolic extract from Sargassum serratifolium and identified sargaquinoic acid (SQA) as an active component. The current study aims to investigate the hypopigmenting action of SQA in α-melanocyte stimulating hormone (α-MSH)-stimulated B16F10 cells. SQA attenuated cellular melanin synthesis by inhibiting the expression of the melanogenic enzymes, including tyrosinase (TYR), tyrosinase-related protein 1 (TRP1), and TRP2...
August 2018: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/29752877/characterization-of-retinal-pigment-epithelial-melanin-and-degraded-synthetic-melanin-using-mass-spectrometry-and-in-vitro-biochemical-diagnostics
#4
Sally M Yacout, Kelsey L McIlwain, Shama P Mirza, Elizabeth R Gaillard
With increasing age, there is an observable loss of melanin in retinal pigment epithelial (RPE) cells. It is possible that degradation of the pigment contributes to the pathogenesis of retinal disease, as the cellular antioxidant material is depleted. Functionally, intact melanin maintains protective qualities, while oxidative degradation of melanin promotes reactive oxygen species (ROS) generation and formation of metabolic byproducts, such as melanolipofuscin. Understanding the structural and functional changes to RPE melanin with increasing age may contribute to a better understanding of disease progression and risk factors for conditions such as age-related macular degeneration (AMD)...
May 12, 2018: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/29735364/methyl-2-acetylamino-3-4-hydroxyl-3-5-dimethoxybenzoylthio-propanoate-suppresses-melanogenesis-through-erk-signaling-pathway-mediated-mitf-proteasomal-degradation
#5
Ji Hoon Ha, Yoon Ju Jeong, Song Hua Xuan, Jae-Young Lee, Jino Park, Soo Nam Park
BACKGROUND: Microphthalmia-associated transcription factor (MITF) is regulated by expression and/or degradation pathway, controlling to the expression of melanogenic enzymes for melanin synthesis. Methyl-2-acetylamino-3-(4-hydroxyl-3,5-dimethoxybenzoylthio)propanoate (MAHDP) is reported to anti-melanogenesis effect but its mechanism remain unclear. OBJECTIVE: To investigate the effects of MAHDP on melanogenesis and elucidate its mechanism. METHODS: Tyrosinase activity, melanogenic proteins and gene expression levels were measured with MAHDP treatment in B16F1 cells, human melanocytes, reconstructed skin and clinical trial...
April 22, 2018: Journal of Dermatological Science
https://www.readbyqxmd.com/read/29709921/3-o-glyceryl-2-o-hexyl-ascorbate-suppresses-melanogenesis-through-activation-of-the-autophagy-system
#6
Yushi Katsuyama, Norihisa Taira, Masato Yoshioka, Yuri Okano, Hitoshi Masaki
The formation of skin pigmentation requires multiple steps, namely the activation of melanocytes, the synthesis of melanin, the transport of melanosomes to the tips of melanocyte dendrites and the transfer of melanosomes from melanocytes to surrounding keratinocytes. Recently, we reported that melanosomes accumulate in melanocytes when melanosome transport is disrupted and that they are then degraded by the autophagy system. In this study, we examined whether 3-O-glyceryl-2-O-hexyl ascorbate (VC-HG) suppresses melanogenesis through the activation of autophagy since VC-HG interferes with melanosome transport through the down-regulated expression of MyosinVa and Kinesin...
2018: Biological & Pharmaceutical Bulletin
https://www.readbyqxmd.com/read/29679020/comparative-genomics-provides-insights-into-the-lifestyle-and-reveals-functional-heterogeneity-of-dark-septate-endophytic-fungi
#7
Dániel G Knapp, Julianna B Németh, Kerrie Barry, Matthieu Hainaut, Bernard Henrissat, Jenifer Johnson, Alan Kuo, Joanne Hui Ping Lim, Anna Lipzen, Matt Nolan, Robin A Ohm, László Tamás, Igor V Grigoriev, Joseph W Spatafora, László G Nagy, Gábor M Kovács
Dark septate endophytes (DSE) are a form-group of root endophytic fungi with elusive functions. Here, the genomes of two common DSE of semiarid areas, Cadophora sp. and Periconia macrospinosa were sequenced and analyzed with another 32 ascomycetes of different lifestyles. Cadophora sp. (Helotiales) and P. macrospinosa (Pleosporales) have genomes of 70.46 Mb and 54.99 Mb with 22,766 and 18,750 gene models, respectively. The majority of DSE-specific protein clusters lack functional annotation with no similarity to characterized proteins, implying that they have evolved unique genetic innovations...
April 20, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29625778/-the-epidermal-barrier
#8
R Abdayem, M Haftek
The skin acts as an interface between the body and its surrounding environment. The epidermis, the surface layer of the skin, is chiefly responsible for this interactive protective function. The epidermal barrier may be subdivided into three defensive systems: the photoprotective barrier, the immune barrier, and the physical and chemical barrier of the stratum corneum or horny layer. To protect against harmful ultraviolet radiation, the epidermis has absorption factors such as melanin, produced by melanocytes, and urocanic acid, which is a degradation product of filaggrin...
April 2018: Annales de Dermatologie et de Vénéréologie
https://www.readbyqxmd.com/read/29623762/degraded-melanocores-are-incompetent-to-protect-epidermal-keratinocytes-against-uv-damage
#9
Wen-Juan Yi, Meng-Yun Su, Ying Shi, Shan Jiang, Shi-Zheng Xu, Tie-Chi Lei
Melanosomes are membrane-bound intracellular organelles that are uniquely generated by melanocytes (MCs) in the basal layer of human epidermis. Highly pigmented mature melanosomes are transferred from MCs to keratinocytes (KCs), and then positioned in the supra-nuclear region to ensure protection against ultraviolet radiation (UVR). However, the molecular mechanism underlying melanosome (or melanin pigment) transfer remains enigmatic. Emerging evidence shows that exo-/endo-cytosis of the melanosome core (termed melanocore) has been considered as the main transfer manner between MCs and KCs...
2018: Cell Cycle
https://www.readbyqxmd.com/read/29518003/insulin-sensitizer-effects-of-fenugreek-seeds-in-parallel-with-changes-in-plasma-mch-levels-in-healthy-volunteers
#10
Rita Kiss, Katalin Szabó, Rudolf Gesztelyi, Sándor Somodi, Péter Kovács, Zoltán Szabó, József Németh, Dániel Priksz, Andrea Kurucz, Béla Juhász, Zoltán Szilvássy
In developed, developing and low-income countries alike, type 2 diabetes mellitus (T2DM) is one of the most common chronic diseases, the severity of which is substantially a consequence of multiple organ complications that occur due to long-term progression of the disease before diagnosis and treatment. Despite enormous investment into the characterization of the disease, its long-term management remains problematic, with those afflicted enduring significant degradation in quality-of-life. Current research efforts into the etiology and pathogenesis of T2DM, are focused on defining aberrations in cellular physiology that result in development of insulin resistance and strategies for increasing insulin sensitivity, along with downstream effects on T2DM pathogenesis...
March 8, 2018: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29509689/novel-furocoumarin-derivatives-stimulate-melanogenesis-in-b16-melanoma-cells-by-up-regulation-of-mitf-and-tyr-family-via-akt-gsk3%C3%AE-%C3%AE-catenin-signaling-pathways
#11
Chao Niu, Li Yin, Haji Akber Aisa
The extracts of Ficuscarica L. and Psoralen corylifolia L. are traditional Uygur medicines for the treatment of vitiligo, and its active ingredients furocoumarins, were are found to be the most effective agents against this skin disorder nowadays. Therefore, a series of novel easter derivatives ( 8a - 8p ) of furocoumarin were designed and synthesized based on our previous research to improve this activity in the present study. The synthesized derivatives were biologically evaluated for melanin synthesis in murine B16 cells and the SAR (structure-activity relationship) was summarized...
March 6, 2018: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29507050/proteomics-of-aspergillus-fumigatus-conidia-containing-phagolysosomes-identifies-processes-governing-immune-evasion
#12
Hella Schmidt, Sebastian Vlaic, Thomas Krüger, Franziska Schmidt, Johannes Balkenhol, Thomas Dandekar, Reinhard Guthke, Olaf Kniemeyer, Thorsten Heinekamp, Axel A Brakhage
Invasive infections by the human pathogenic fungus Aspergillus fumigatus start with the outgrowth of asexual, airborne spores (conidia) into the lung tissue of immunocompromised patients. The resident alveolar macrophages phagocytose conidia, which end up in phagolysosomes. However, A. fumigatus conidia resist phagocytic degradation to a certain degree. This is mainly attributable to the pigment 1,8-dihydroxynaphthalene (DHN) melanin located in the cell wall of conidia, which manipulates the phagolysosomal maturation and prevents their intracellular killing...
June 2018: Molecular & Cellular Proteomics: MCP
https://www.readbyqxmd.com/read/29486182/phytol-suppresses-melanogenesis-through-proteasomal-degradation-of-mitf-via-the-ros-erk-signaling-pathway
#13
Gyeong-A Ko, Somi Kim Cho
Phytol (3,7,11,15-tetramethyl-2-hexadecen-1-ol) is an acyclic monounsaturated diterpene alcohol generated from chlorophyll metabolism that exerts anti-inflammatory, antithrombotic, antimicrobial, and antitumor effects. However, the effect of phytol on melanogenesis and the underlying molecular mechanisms of its inhibition remain unknown. Here, we found that phytol suppressed α-melanocyte-stimulating hormone-induced melanogenesis in B16F10 murine melanoma cells without any toxic effects. Phytol significantly attenuated melanin production by reducing the expression of tyrosinase and tyrosinase related protein 1...
April 25, 2018: Chemico-biological Interactions
https://www.readbyqxmd.com/read/29481571/17-aag-inhibits-vemurafenib-associated-map-kinase-activation-and-is-synergistic-with-cellular-immunotherapy-in-a-murine-melanoma-model
#14
Sandeep S Joshi, Shunlin Jiang, Emmanual Unni, Stephen R Goding, Tao Fan, Paul A Antony, Thomas J Hornyak
Heat shock protein 90 (HSP90) is a molecular chaperone which stabilizes client proteins with important roles in tumor growth. 17-allylamino-17-demethoxygeldanamycin (17-AAG), an inhibitor of HSP90 ATPase activity, occupies the ATP binding site of HSP90 causing a conformational change which destabilizes client proteins and directs them towards proteosomal degradation. Malignant melanomas have active RAF-MEK-ERK signaling which can occur either through an activating mutation in BRAF (BRAFV600E) or through activation of signal transduction upstream of BRAF...
2018: PloS One
https://www.readbyqxmd.com/read/29477191/shining-a-light-on-black-holes-in-keratinocytes
#15
Shanna L Bowman, Michael S Marks
The mechanisms by which melanins are transferred from melanocytes and stored within keratinocytes to generate skin pigmentation are hotly debated. Correia et al. and Hurbain et al. provide evidence that melanin cores of melanosomes are secreted from melanocytes and taken up and stored within non-degradative membranous organelles in keratinocytes in the basal epidermis of human skin.
March 2018: Journal of Investigative Dermatology
https://www.readbyqxmd.com/read/29442220/methylquercetins-stimulate-melanin-biosynthesis-in-a-three-dimensional-skin-model
#16
Kosei Yamauchi, Tohru Mitsunaga
In a previous study, we found that both synthetic 3-O-methylquercetin (3MQ) and 3,4',7-O-trimethylquercetin (34'7TMQ) increased extracellular melanin content. 34'7TMQ increased the activity of melanogenic enzymes by stimulating the p38 pathway and the expression of microphthalmia-associated transcription factor (MITF). In contrast, 3MQ increased the activity of melanogenic enzymes without the involvement of MITF, which suggests that 3MQ inhibits the degradation of melanogenic enzymes. In the present study, we investigated the effects of 3MQ and 34'7TMQ on melanogenesis in normal human melanocytes and using a commercial three-dimensional (3D) skin model system...
March 2018: Journal of Natural Medicines
https://www.readbyqxmd.com/read/29385729/antioxidative-and-anti-melanogenic-activities-of-bamboo-stems-phyllostachys-nigra-variety-henosis-via-pka-creb-mediated-mitf-downregulation-in-b16f10-melanoma-cells
#17
Moon-Hee Choi, Han-Gyo Jo, Ji Hye Yang, Sung Hwan Ki, Hyun-Jae Shin
Phyllostachys nigra var. henosis, a domestic bamboo species, has been attracting much attention; its bioactive compounds (especially in the leaf) show antioxidant, anti-inflammatory, and anti-obesity activities. Little information is available on the antioxidative and anti-melanogenetic activities of the bioactive compounds in bamboo stems. The anti-melanogenic and antioxidative activities of the EtOAc fraction (PN3) of a P. nigra stem extract were investigated in a cell-free system and in B16F10 melanoma cells...
January 30, 2018: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29320400/posidonia-oceanica-l-delile-ethanolic-extract-modulates-cell-activities-with-skin-health-applications
#18
Laura Cornara, Giulia Pastorino, Barbara Borghesi, Annalisa Salis, Marco Clericuzio, Carla Marchetti, Gianluca Damonte, Bruno Burlando
Seagrasses are high plants sharing adaptive metabolic features with both terrestrial plants and marine algae, resulting in a phytocomplex possibly endowed with interesting biological properties. The aim of this study is to evaluate the in vitro activities on skin cells of an ethanolic extract obtained from the leaves of Posidonia oceanica (L.) Delile, family Potamogetonaceae, herein named Posidonia ethanolic extract (PEE). PEE showed high radical scavenging activity, high phenolic content, and resulted rich in chicoric acid, as determined through HPLC-MS analysis...
January 10, 2018: Marine Drugs
https://www.readbyqxmd.com/read/29160957/insect-cuticular-melanins-are-distinctly-different-from-those-of-mammalian-epidermal-melanins
#19
Hanine Barek, Manickam Sugumaran, Shosuke Ito, Kazumasa Wakamatsu
Melanin from several insect samples was isolated and subjected to chemical degradation and HPLC analysis for melanin markers. Quantification of different melanin markers reveals that insect melanins are significantly different from that of the mammalian epidermal melanins. The eumelanin produced in mammals is derived from the oxidative polymerization of both 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acids. The pheomelanin is formed by the oxidative polymerization of cysteinyldopa. Thus, dopa is the major precursor for both eumelanin and pheomelanin in mammals...
May 2018: Pigment Cell & Melanoma Research
https://www.readbyqxmd.com/read/29158724/comparative-proteomic-analysis-between-nitrogen-supplemented-and-starved-conditions-in-magnaporthe-oryzae
#20
Yeonyee Oh, Suzanne L Robertson, Jennifer Parker, David C Muddiman, Ralph A Dean
Background: Fungi are constantly exposed to nitrogen limiting environments, and thus the efficient regulation of nitrogen metabolism is essential for their survival, growth, development and pathogenicity. To understand how the rice blast pathogen Magnaporthe oryzae copes with limited nitrogen availability, a global proteome analysis under nitrogen supplemented and nitrogen starved conditions was completed. Methods: M. oryzae strain 70-15 was cultivated in liquid minimal media and transferred to media with nitrate or without a nitrogen source...
2017: Proteome Science
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