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Biomolecules & Therapeutics Mar 2024Methyl anthranilate (MA) is a botanical fragrance used in food flavoring with unexplored potential in anti-pigment cosmetics. MA dose-dependently reduced melanin content...
Methyl anthranilate (MA) is a botanical fragrance used in food flavoring with unexplored potential in anti-pigment cosmetics. MA dose-dependently reduced melanin content without affecting cell viability, inhibited dendrite elongation and melanosome transfer in the co-culture system of human melanoma cells (MNT-1) and human keratinocyte cell line (HaCaT), and downregulated melanogenic genes, including tyrosinase, tyrosinase-related protein 1 and 2 (TRP-1, TRP-2). Additionally, MA decreased cyclic adenosine monophosphate (cAMP) production and exhibited a significant anti-pigmentary effect in Melanoderm™. These results suggest that MA is a promising anti-pigmentary agent for replacing or complementing existing anti-pigmentary cosmetics.
PubMed: 38296651
DOI: 10.4062/biomolther.2023.103 -
Comparative Biochemistry and... Mar 2024Marine bivalves are economically important and exhibit a remarkable diversity in shell color. The Pacific oyster Crassostrea gigas stands out as an important economic...
Marine bivalves are economically important and exhibit a remarkable diversity in shell color. The Pacific oyster Crassostrea gigas stands out as an important economic species, with the successful development of four distinct color strains through selective breeding. While previous studies have shed light on the genetic mechanism underlying color segregation, the precise molecular regulatory mechanisms responsible for shell coloration in oysters remains elusive. In this study, we confirmed that the golden phenotype is primarily attributed to pheomelanin by histological and ultrastructural observations. Additionally, we conducted a comparative transcriptome analysis of the black and golden shell color oysters to explore the potential genes and pathways contributing to the golden phenotype in C. gigas. Our results revealed a significant increase in differentially expressed genes in the golden phenotype associated with pathways such as glutathione metabolism, and calcium signaling pathway, suggesting a potential role in the synthesis of pheomelanin. Of particular note, we highlighted the potential role of two-pore channel 2 (TPC2) in modulating tyrosinase activity and melanosomal pH, ultimately determining the shade of pigmentation. Our study in this work provided a preliminary exploration of the mechanism, shedding light on the melanosome microenvironment and shell color.
Topics: Animals; Transcriptome; Crassostrea; Phenotype; Gene Expression Profiling
PubMed: 38295536
DOI: 10.1016/j.cbd.2024.101197 -
Scientific Reports Jan 2024Tyrosinase (Tyr) is a key enzyme in the process of melanin synthesis that occurs exclusively within specialized organelles called melanosomes in melanocytes. Tyr is...
Tyrosinase (Tyr) is a key enzyme in the process of melanin synthesis that occurs exclusively within specialized organelles called melanosomes in melanocytes. Tyr is synthesized and post-translationally modified independently of the formation of melanosome precursors and then transported to immature melanosomes by a series of membrane trafficking events that includes endoplasmic reticulum (ER)-to-Golgi transport, post-Golgi trafficking, and endosomal transport. Although several important regulators of Tyr transport have been identified, their precise role in each Tyr transport event is not fully understood, because Tyr is present in several melanocyte organelles under steady-state conditions, thereby precluding the possibility of determining where Tyr is being transported at any given moment. In this study, we established a novel synchronized Tyr transport system in Tyr-knockout B16-F1 cells by using Tyr tagged with an artificial oligomerization domain FM4 (named Tyr-EGFP-FM4). Tyr-EGFP-FM4 was initially trapped at the ER under oligomerized conditions, but at 30 min after chemical dissociation into monomers, it was transported to the Golgi and at 9 h reached immature melanosomes. Melanin was then detected at 12 h after the ER exit of Tyr-EGFP-FM4. By using this synchronized Tyr transport system, we were able to demonstrate that Tyr-related protein 1 (Tyrp1), another melanogenic enzyme, is a positive regulator of efficient Tyr targeting to immature melanosomes. Thus, the synchronized Tyr transport system should serve as a useful tool for analyzing the molecular mechanism of each Tyr transport event in melanocytes as well as in the search for new drugs or cosmetics that artificially regulate Tyr transport.
Topics: Melanosomes; Monophenol Monooxygenase; Melanins; Melanogenesis; Melanocytes
PubMed: 38291221
DOI: 10.1038/s41598-024-53072-6 -
Journal of Biosciences 2024Oculocutaneous albinism (OCA) is characterized by reduced melanin biosynthesis affecting the retina, thus impairing visual function. The disease pathology of OCA is...
Oculocutaneous albinism (OCA) is characterized by reduced melanin biosynthesis affecting the retina, thus impairing visual function. The disease pathology of OCA is poorly understood at the cellular level due to unavailability of suitable biological model systems. This study aimed to develop a disease-specific model for OCA type 1A, the most severe form caused by (tyrosinase) gene mutations, using retinal pigment epithelium (RPE) differentiated from patient-derived human-induced pluripotent stem cells (hiPSCs). A comparative study between healthy and OCA1A RPE cells revealed that while healthy RPE cells exhibited timely onest of pigmentation during differentiation, OCA1A RPE cells failed to pigment even after an extended culture period. This observation was validated by ultrastructural studies using electron microscopy, hinting at melanosome-specific defects. Immunocytochemistry demonstrated abnormal expression patterns of melanogenesis-specific protein markers in OCA1A RPE cells, indicating reduced or absence of melanin synthesis. Next, a quantitative assay was performed to confirm the absence of melanin production in OCA1A RPE cells. Tyrosinase assay showed no activity in OCA1A compared with healthy RPE, suggesting non-functionality of , further corroborated by western blot analysis showing complete absence of the protein. Gene expression by RNA sequencing of healthy and OCA1A RPE cells uncovered differential gene expression associated with lens development, visual perception, transmembrane transporter activity, and key signaling pathways. This disease-in-a-dish model of OCA1A provides an excellent platform to understand disease mechanism, identify potential therapeutic targets, and facilitate gene therapy or gene correction.
Topics: Humans; Melanins; Monophenol Monooxygenase; Induced Pluripotent Stem Cells; Retinal Pigment Epithelium; Albinism, Oculocutaneous
PubMed: 38287676
DOI: No ID Found -
Investigative Ophthalmology & Visual... Jan 2024Pigmentation in uveal melanoma is associated with increased malignancy and is known as a barrier for photodynamic therapy. We investigated the role of pigmentation in...
PURPOSE
Pigmentation in uveal melanoma is associated with increased malignancy and is known as a barrier for photodynamic therapy. We investigated the role of pigmentation in tumor behavior and the response to light-activated Belzupacap sarotalocan (Bel-sar) treatment in a pigmented (wild type) and nonpigmented (tyrosinase knock-out [TYR knock-out]) cell line in vitro and in a murine model.
METHODS
The B16F10 (TYR knock-out) was developed using CRISPR/Cas9. After the treatment with light-activated Bel-sar, cytotoxicity and exposure of damage-associated molecular patterns (DAMPs) were measured by flow cytometry. Treated tumor cells were co-cultured with bone marrow-derived macrophages (BMDMs) and dendritic cells (DCs) to assess phagocytosis and activation. Both cell lines were injected subcutaneously in syngeneic C57BL/6 mice.
RESULTS
Knock-out of the tyrosinase gene in B16F10 led to loss of pigmentation and immature melanosomes. Pigmented tumors contained more M1 and fewer M2 macrophages compared with amelanotic tumors. Bel-sar treatment induced near complete cell death, accompanied with enhanced exposure of DAMPs in both cell lines, resulting in enhanced phagocytosis of BMDMs and maturation of DCs. Bel-sar treatment induced a shift to M1 macrophages and delayed tumor growth in both in vivo tumor models. Following treatment, especially the pigmented tumors and their draining lymph nodes contained IFN-gamma positive CD8+T cells.
CONCLUSIONS
Pigmentation influenced the type of infiltrating macrophages in the tumor, with more M1 macrophages in pigmented tumors. Belzupacap sarotalocan treatment induced immunogenic cell death and tumor growth delay in pigmented as well as in nonpigmented models and stimulated M1 macrophage influx in both models.
Topics: Animals; Mice; Melanoma; Monophenol Monooxygenase; Mice, Inbred C57BL; Macrophages; Pigmentation
PubMed: 38271187
DOI: 10.1167/iovs.65.1.42 -
Cell Biology International Apr 2024The ion channel two-pore channel 2 (TPC2), localised on the membranes of acidic organelles such as endo-lysosomes and melanosomes, has been shown to play a role in...
The ion channel two-pore channel 2 (TPC2), localised on the membranes of acidic organelles such as endo-lysosomes and melanosomes, has been shown to play a role in pathologies including cancer, and it is differently expressed in primary versus metastatic melanoma cells. Whether TPC2 plays a pro- or anti-oncogenic role in different tumour conditions is a relevant open question which we have explored in melanoma at different stages of tumour progression. The behaviour of primary melanoma cell line B16F0 and its metastatic subline B16F10 were compared in response to TPC2 modulation by silencing (by small interfering RNA), knock-out (by CRISPR/Cas9) and overexpression (by mCherry-TPC2 transfected plasmid). TPC2 silencing increased cell migration, epithelial-to-mesenchymal transition and autophagy in the metastatic samples, but abated them in the silenced primary ones. Interestingly, while TPC2 inactivation failed to affect markers of proliferation in both samples, it strongly enhanced the migratory behaviour of the metastatic cells, again suggesting that in the more aggressive phenotype TPC2 plays a specific antimetastatic role. In line with this, overexpression of TPC2 in B16F10 cells resulted in phenotype rescue, that is, a decrease in migratory ability, thus collectively resuming traits of the B16F0 primary cell line. Our research shows a novel role of TPC2 in melanoma cells that is intriguingly different in initial versus late stages of cancer progression.
Topics: Humans; Melanoma; Two-Pore Channels; Lysosomes; Cell Line; Autophagy; Calcium
PubMed: 38263578
DOI: 10.1002/cbin.12129 -
International Journal of Molecular... Dec 2023In the retina, retinoids involved in vision are under constant threat of oxidation, and their oxidation products exhibit deleterious properties. Using pulse radiolysis,...
In the retina, retinoids involved in vision are under constant threat of oxidation, and their oxidation products exhibit deleterious properties. Using pulse radiolysis, this study determined that the bimolecular rate constants of scavenging cation radicals of retinoids by taurine are smaller than 2 × 10 Ms whereas lutein scavenges cation radicals of all three retinoids with the bimolecular rate constants approach the diffusion-controlled limits, while zeaxanthin is only 1.4-1.6-fold less effective. Despite that lutein exhibits greater scavenging rate constants of retinoid cation radicals than other antioxidants, the greater concentrations of ascorbate in the retina suggest that ascorbate may be the main protectant of all visual cycle retinoids from oxidative degradation, while α-tocopherol may play a substantial role in the protection of retinaldehyde but is relatively inefficient in the protection of retinol or retinyl palmitate. While the protection of retinoids by lutein and zeaxanthin appears inefficient in the retinal periphery, it can be quite substantial in the macula. Although the determined rate constants of scavenging the cation radicals of retinol and retinaldehyde by dopa-melanin are relatively small, the high concentration of melanin in the RPE melanosomes suggests they can be scavenged if they are in proximity to melanin-containing pigment granules.
Topics: Retinoids; Vitamin A; Melanins; Retinaldehyde; Lutein; Zeaxanthins; Taurine; Cations
PubMed: 38203675
DOI: 10.3390/ijms25010506 -
Doklady. Biochemistry and Biophysics Dec 2023In mammals, the main contribution to the variability of pigmentation is made by two groups of genes directly related to the metabolic pathways of pigment synthesis and...
In mammals, the main contribution to the variability of pigmentation is made by two groups of genes directly related to the metabolic pathways of pigment synthesis and controlling the transport of melanosomes in melanocytes to keratinocytes. In order to identify the genetic basis of pigmentation variants, the nucleotide sequences of the melanophilin gene were compared in two groups of ferrets-silver-colored and wild-type animals-using sequencing of 16 exons. In carriers of silver color, a single nucleotide deletion was detected in the 9th exon, leading to a shift in the reading frame and the formation of a stop codon downstream. The protein encoded by the mutant allele is almost completely devoid of the C terminal domain of the protein responsible for the contact of melanosomes with actin during their moving to the periphery of melanocytes, but it retains the leading domain involved in the formation of melanosomes. The combination of the preservation of the N domain and the defect of the C domain of the mutant protein for the first time makes it possible to explain the incomplete dominance of the wild-type protein in heterozygotes.
Topics: Animals; Ferrets; Silver; Melanocytes; Melanosomes; Exons
PubMed: 38189891
DOI: 10.1134/S1607672923700655 -
International Journal of Biological... 2024The cAMP response element-binding protein (CREB) and CREB-regulated transcription coactivators (CRTCs) cooperate in the transcriptional activation of...
The cAMP response element-binding protein (CREB) and CREB-regulated transcription coactivators (CRTCs) cooperate in the transcriptional activation of microphthalmia-associated transcription factor subtype M (MITF-M) that is a master regulator in the biogenesis, pigmentation and transfer of melanosomes at epidermal melanocytes. Here, we propose the targeting of phosphorylation circuits on CREB and CRTCs in the expression of MITF-M as the rationale to prevent skin hyperpigmentation by elucidating the inhibitory activity and mechanism of yakuchinone A (Yaku A) on facultative melanogenesis. We employed human epidermal melanocyte cell, mouse skin, and mouse melanoma cell, and applied Western blotting, reverse transcription-polymerase chain reaction, immunoprecipitation and confocal microscopy to conduct this study. This study suggested that α-melanocyte stimulating hormone (α-MSH)-induced melanogenic programs could switch on the axis of protein kinase A-salt inducible kinases (PKA-SIKs) rather than that of PKA-AMP activated protein kinase (PKA-AMPK) during the dephosphorylation of CRTCs in the expression of MITF-M. SIK inhibitors rather than AMPK inhibitors stimulated melanin production in melanocyte cultures in the absence of extracellular melanogenic stimuli, wherein SIK inhibitors increased the dephosphorylation of CRTCs but bypassed the phosphorylation of CREB for the expression of MITF-M. Treatment with Yaku A prevented ultraviolet B (UV-B)-irradiated skin hyperpigmentation in mice and inhibited melanin production in α-MSH- or SIK inhibitor-activated melanocyte cultures. Mechanistically, Yaku A suppressed the expression of MITF-M via dually targeting the i) cAMP-dependent dissociation of PKA holoenzyme at the upstream from PKA-catalyzed phosphorylation of CREB coupled with PKA-SIKs axis-mediated dephosphorylation of CRTCs in α-MSH-induced melanogenic programs, and ii) nuclear import of CRTCs after SIK inhibitor-induced dephosphorylation of CRTCs. Taken together, the targeting phosphorylation circuits on CREB and CRTCs in the expression of MITF-M could be a suitable strategy to prevent pigmentary disorders in the skin.
Topics: Humans; Animals; Mice; Melanins; Cyclic AMP Response Element-Binding Protein; Phosphorylation; alpha-MSH; AMP-Activated Protein Kinases; Melanocytes; Hyperpigmentation; Microphthalmia-Associated Transcription Factor; Cell Line, Tumor
PubMed: 38164184
DOI: 10.7150/ijbs.86536 -
Journal of Ethnopharmacology Apr 2024Tribuloside, a natural flavonoid extracted from Chinese medicine Tribulus terrestris L., has shown potent efficacy in treating various diseases. In China, the fruits of...
ETHNOPHARMACOLOGICAL RELEVANCE
Tribuloside, a natural flavonoid extracted from Chinese medicine Tribulus terrestris L., has shown potent efficacy in treating various diseases. In China, the fruits of Tribulus terrestris L. have long been utilized for relieving headache, dizziness, itchiness, and vitiligo. Water-based extract derived from Tribulus terrestris L. can enhance melanogenesis in mouse hair follicle melanocytes by elevating the expression of α-melanocyte stimulating hormone (α-MSH) and melanocortin-1 recepter (MC-1R). Nevertheless, there is a lack of information regarding the impact of tribuloside on pigmentation in both laboratory settings and living organisms.
AIM OF THE STUDY
The present research aimed to examine the impact of tribuloside on pigmentation, and delve into the underlying mechanism.
MATERIALS AND METHODS
Following the administration of tribuloside in human epidermal melanocytes (HEMCs), we utilized microplate reader, Masson-Fontana ammoniacal silver stain, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) to measure melanin contents, dendrite lengths, melanosome counts; L-DOPA oxidation assay to indicate tyrosinase activity, Western blotting to evaluate the expression of melanogenic and associated phosphodiesterase (PDE)/cyclic adenosine monophosphate (cAMP)/cyclic-AMP dependent protein kinase A (PKA) pathway proteins. A PDE-Glo assay to verify the inhibitory effect of tribuloside on PDE was also conducted. Additionally, we examined the impact of tribuloside on the pigmentation in both zebrafish model and human skin samples.
RESULTS
Tribuloside had a notable impact on the production of melanin in melanocytes, zebrafish, and human skin samples. These functions might be attributed to the inhibitory effect of tribuloside on PDE, which could increase the intracellular level of cAMP to stimulate the phosphorylation of cAMP-response element binding (CREB). Once activated, it induced microphthalmia-associated transcription factor (MITF) expression and increased the expression of tyrosinase, Rab27a and cell division cycle protein 42 (Cdc42), ultimately facilitating melanogenesis, melanocyte dendricity, and melanin transport.
CONCLUSION
Tribuloside acts on the PDE/cAMP/PKA pathway to enhance melanogenesis, melanocyte dendricity, and melanosome transport; meanwhile, tribuloside does not have any toxic effects on cells and may be introduced into clinical prescriptions to promote pigmentation.
Topics: Animals; Mice; Humans; Melanins; Melanosomes; Zebrafish; Monophenol Monooxygenase; Melanogenesis; Phosphoric Diester Hydrolases; Cyclic AMP-Dependent Protein Kinases; Melanocytes; Cyclic AMP; Microphthalmia-Associated Transcription Factor; Cell Line, Tumor
PubMed: 38158096
DOI: 10.1016/j.jep.2023.117673