This study aimed to evaluate the biological effect and mechanism of Vernonia anthelmintica Injection(VAI) on melanin accumulation. The in vivo depigmentation model was induced by propylthiouracil(PTU) in zebrafish, and the effect of VAI on melanin accumulation was evaluated based on the in vitro B16F10 cell model. The chemical composition of VAI was identified according to the high-performance liquid chromatography quadrupole-time-of-flight tandem mass spectrometry(UPLC-Q-TOF-MS). Network pharmaco-logy was applied to predict potential targets and pathways of VAI. A "VAI component-target-pathway" network was established, and the pharmacodynamic molecules were screened out based on the topological characteristics of the network. The binding of active molecules to key targets was verified by molecular docking. The results showed that VAI promoted tyrosinase activity and melanin production in B16F10 cells in a dose-and time-dependent manner and could restore the melanin in the body of the zebrafish model. Fifty-six compounds were identified from VAI, including flavonoids(15/56), terpenoids(10/56), phenolic acids(9/56), fatty acids(9/56), steroids(6/56), and others(7/56). Network pharmacological analysis screened four potential quality markers, including apigenin, chrysoeriol, syringaresinol, and butein, involving 61 targets and 65 pathways, and molecular docking verified their binding to TYR, NFE2L2, CASP3, MAPK1, MAPK8, and MAPK14. It was found that the mRNA expression of MITF, TYR, TYRP1, and DCT in B16F10 cells was promoted. By UPLC-Q-TOF-MS and network pharmacology, this study determined the material basis of VAI against vitiligo, screened apigenin, chrysoeriol, syringaresinol, and butein as the quality markers of VAI, and verified the efficacy and internal mechanism of melanogenesis, providing a basis for quality control and further clinical research.
Animals ; Vernonia/chemistry* ; Melanins/metabolism* ; Zebrafish/metabolism* ; Network Pharmacology ; Molecular Docking Simulation ; Apigenin/pharmacology* ; Drugs, Chinese Herbal/pharmacology* ; Chromatography, High Pressure Liquid

OBJECTIVE: To investigate the physicochemical characteristics of natural melanin-like nanoparticles (PDA NPs) and their synergistic anti-tumor efficacy with photothermal and photodynamic (PTT/PDT) therapy. METHODS: The chemically synthesized PDA NPs were characterized using transmission electron microscope (TEM), dynamic light scattering (DLS) and Zeta potential analysis, and their photothermal and photodynamic properties were assessed with near-infrared excitation light (NIR). The antitumor efficacy of free PDA or PDA combined with NIR irradiation (0.7 and 1.0 W/cm²) was evaluated in ovarian cancer cells using flow cytometry, Cell Counting Kit-8 (CCK-8), and Transwell assay and in a mouse model bearing subcutaneous ovarian cancer xenograft. RESULTS: The synthesized PDA NPs showed a spherical morphology with diameters around 100 nm and a zeta potential of -20 mV. Upon NIR irradiation at 0.7 and 1.0 W/cm², the particles underwent temperature changes (ΔT) of about 15 and 30 ℃, respectively, and produced a large amount of singlet oxygen, demonstrating their excellent PTT/PDT properties. In ovarian cancer cells, treatment with PDA NPs alone did not induce obvious changes in reactive oxygen species (ROS) production or mitochondrial membrane potential (MTP), but when combined with NIR irradiation, these particles caused a significant increase of ROS and a reduction of MTP (P < 0.001), and such changes were more prominent with high power NIR (P < 0.01). PDA NPs alone showed no obvious cytotoxicity, but the combination of PDA with NIR irradiation produced potent killing effect on ovarian cancer cells (P < 0.001), and the effect was much stronger with a high power irradiation (P < 0.001). While PDA alone showed no inhibitory effect on tumor cell metastasis, the combined treatment with PDA and NIR irradiation, especially at a high power, significantly suppressed invasion and migration of ovarian cancer cells (P < 0.001). In the tumor-bearing mouse model, the combined treatment, but not PDA alone, produced a significant inhibitory effect on tumor growth (P < 0.001). CONCLUSION PDA NPs combined with NIR has a strong anti-tumor effect, suggesting a potential new therapeutic strategy for ovarian cancer.
Humans ; Animals ; Mice ; Female ; Melanins ; Ovarian Neoplasms/therapy* ; Cell Death ; Nanoparticles ; Antibodies

Cell Line, Tumor ; Cell Proliferation ; Humans ; Melanins ; Melanoma ; Particulate Matter

Objective: To investigate the ultrasonographic features and clinical pathological of liver metastasis in patients with melanoma. Methods: Thirteen patients with liver metastasis from melanoma treated in Tianjin Medical University Cancer Institute and Hospital from 2013 to 2019 were selected, and their ultrasonographic and clinicopathological characteristics were analyzed retrospectively. Results: Eleven of the 13 patients had multiple liver lesions. The maximum diameter of the lesions was (5.89±2.73) cm. Five cases of lesions were mixed echo (3 cases with high melanin content), 4 cases of lesions were hyperechoic (3 cases with low melanin content), 3 cases of lesions were hypoechoic (all with high melanin content), 1 case of lesions were equal echo (with high melanin content). The lesions in 11 patients had clear boundaries, while other 2 patients lacked the clear borders. Cystic areas were present in the lesions of 3 patients. Six cases had irregular lesions (lobulated), and 7 cases had regular lesions (round, oval). There were acoustic halos around the lesion in 9 cases and smooth and uneven acoustic halos in 5 cases. The results of immunohistochemistry showed that 11 cases were positive for S-100, HMB45 and Melan-A. One patient was not tested for HMB45, while S-100 and Melan-A were positive. One patient did not undergo Melan-A test, while S-100 and HMB45 were positive. Conclusion: Most of the liver metastases of melanoma are mixed echo or hyperechoic, most of them are nodular with clear boundaries combined with vocal halo, and a few of the lesions have cystic areas.
Humans ; Liver Neoplasms/secondary* ; MART-1 Antigen ; Melanins ; Melanoma/pathology* ; Retrospective Studies

Ascosphaera apis spores containing a dark-colored pigment infect honeybee larvae, resulting in a large-scale collapse of the bee colony due to chalkbrood disease. However, little is known about the pigment or whether it plays a role in bee infection caused by A. apis. In this study, the pigment was isolated by alkali extraction, acid hydrolysis, and repeated precipitation. Ultraviolet (UV) analysis revealed that the pigment had a color value of 273, a maximum absorption peak at 195 nm, and a high alkaline solubility (7.67%) and acid precipitability. Further chemical structure analysis of the pigment, including elemental composition, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, mass spectrometry, and nuclear magnetic resonance (NMR), proved that it was a eumelanin with a typical indole structure. The molecular formula of melanin is C₁₀H₆O₄N₂, and its molecular weight is 409 Da. Melanin has hydroxyl, carboxyl, amino, and phenolic groups that can potentially chelate to metal ions. Antioxidant function analyses showed that A. apis melanin had a high scavenging activity against superoxide, hydroxyl, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, and a high reducing ability to Fe³⁺. Indirect immunofluorescence assay (IFA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analyses showed that A. apis melanin was located on the spore wall. The spore wall localization, antioxidant activity, and metal ion chelating properties of fungal melanin have been suggested to contribute to spore pathogenicity. However, further infection experiments showed that melanin-deficient spores did not reduce the mortality of bee larvae, indicating that melanin does not increase the virulence of A. apis spores. This study is the first report on melanin produced by A. apis, providing an important background reference for further study on its role in A. apis.
Animals ; Antioxidants/pharmacology* ; Larva ; Melanins ; Molecular Structure ; Onygenales

Opsin3 (OPN3) is a photoreceptor membrane protein with a typical seven-alpha helical transmembrane structure that belongs to the G-protein-coupled receptor (GPCR) superfamily and is widely expressed in brain. In recent years, it has been reported that OPN3 is also highly expressed in adipose tissue, and the protein is associated with the production of skin melanin. We found that the N82 site is the glycosylation site of OPN3. SNAP-tag^TM has diverse functions and can be applied to a variety of different studies. By constructing a SNAP-tagged OPN3 recombinant protein, the distribution position of SNAP-OPN3 in cells can be clearly observed by fluorescence confocal microscopy using SNAP-Surface^® 549 and SNAP-Cell^® OregonGreen^®, which provides a new method for studying the function of OPN3. It also shows that SNAP-tag does not affect the function of OPN3. Using the SNAP tag we found that OPN3 cannot be taken up to the cell membrane after glycosylation site mutation.
Cell Membrane ; Glycosylation ; Melanins ; Membrane Proteins ; Skin

Keloids are a common type of pathological scar as a result of skin healing, which are extremely difficult to prevent and treat without recurrence. The pathological mechanism of keloids is the excessive proliferation of fibroblasts, which synthesize more extracellular matrices (ECMs), including type I/III collagen (COL-1/3), mucopolysaccharides, connective tissue growth factor (CTGF, also known as cellular communication network factor 2 (CCN2)), and fibronectin (FN) in scar tissue, mostly through the abnormal activation of transforming growth factor-‍β (TGF-‍β)/Smads pathway (Finnson et al., 2013; Song et al., 2018). Genetic factors, including race and skin tone, are considered to contribute to keloid formation. The reported incidence of keloids in black people is as high as 16%, whereas white people are less affected. The prevalence ratio of colored people to white people is 5:1‍‍-‍‍15:1 (Rockwell et al., 1989; LaRanger et al., 2019). In addition, keloids have not been reported in albinism patients of any race, and those with darker skin in the same race are more likely to develop this disease (LaRanger et al., 2019). Skin melanocyte activity is significantly different among people with different skin tones. The more active the melanocyte function, the more melanin is produced and the darker the skin. Similarly, in the same individual, the incidence of keloids increases during periods when melanocytes are active, such as adolescence and pregnancy. Keloids rarely appear in areas where melanocytes synthesize less melanin, such as in the palms and soles. Thus, the formation of keloids seems to be closely related to melanocyte activity.
Adolescent ; Cells, Cultured ; Exosomes/metabolism* ; Fibroblasts/metabolism* ; Humans ; Keloid/pathology* ; Melanins/metabolism* ; Melanocytes/pathology* ; Pilot Projects ; Skin/metabolism* ; Transforming Growth Factor beta/metabolism*

Objective: Owing to antibiotic abuse and the subsequent development of antibiotic resistance, bacterial infection has become one of the most persistent unresolved problems. New antibacterial agents, especially those that are environmental-friendly, are urgently needed. Methods: Melanin extracted by filtration centrifugation and acid and proteolytic hydrolysis was characterized using UV, FTIR, TEM, and XPS. Photothermal conversion was calculated, and the bacteriostatic effects, and , were assessed by plate counting and ratios (%) of wound areas. Results: Natural melanin hydrolyzed by trypsin had good photothermal conversion effects, which resulted in superior bacteriostatic activities. The extracted melanin along with laser NIR irradiation at 808 nm promoted the healing of wounds infected by drug-resistant bacteria and was biocompatible according to toxicity tests and . Conclusion The present findings indicated a safe and efficient method of developing natural antibacterial agents.
Animal Shells ; chemistry ; Animals ; Anti-Bacterial Agents ; pharmacology ; Escherichia coli ; drug effects ; radiation effects ; Escherichia coli Infections ; drug therapy ; Melanins ; pharmacology ; Mytilus edulis ; chemistry ; Photochemical Processes ; Rats ; Rats, Sprague-Dawley ; Staphylococcal Infections ; drug therapy ; Staphylococcus aureus ; drug effects ; radiation effects ; Wound Healing

Increasing evidence suggests that stress may induce changes in hair color, with the underlying mechanism incompletely understood. In this study, female C57BL/6 mice subjected to electric foot shock combined with restraint stress were used to build chronic stress mouse model. The melanin contents and tyrosinase activity were measured in mouse skin and B16F10 melanoma cells. The enzyme-linked immunosorbent assay (ELISA) was used to determine the content of tumor necrosis factor α (TNF-α), interleukin- 1β (IL-1β) and interleukin-6 (IL-6) in the mouse skin. The content of nuclear factor κB (NFκB)/p65 subunit in mouse skins was valued by immunofluorescence staining. The results demonstrated that under chronic stress, the fur color turned from dark to brown in C57BL/6 mice due to the decrease of follicle melanocytes and tyrosinase activity in C57BL/6 mouse skin. Simultaneously, inflammatory responses in skins were detected as shown by increased NFκB activity and TNF-α expression in stressed mouse skin. In cultured B16F10 melanoma cells, TNF-α reduced the melanogenesis and tyrosinase activity in a dose-dependent manner. These findings indicate that chronic stress induces fur color change by decreasing follicle melanocytes and tyrosinase activity in female C57BL/6 mice, and TNF-α may play an important role in stress-induced hair color change.
Animal Fur ; Animals ; Color ; Female ; Melanins ; Melanocytes ; enzymology ; Melanoma, Experimental ; Mice ; Mice, Inbred C57BL ; Monophenol Monooxygenase ; metabolism ; Pigmentation ; Skin ; physiopathology ; Stress, Physiological

Melanin is an important factor affecting human skin color. This study defines its synthetic pathways and regulatory pathways have the practical significance for the treatment of diseases caused by pigmentation problems, such as chloasma. Besides, it also provides a theoretical basis for screening out melanin inhibitors and developing whitening and freckle products. At present, the melanin inhibitors used in whitening and freckle products mainly come from natural products and traditional Chinese medicine. This article first introduces the melanin biosynthesis pathway with tyrosinase as the core, defines the synthesis, transport and catalytic activity of tyrosinase as the three key factors affecting melanin synthesis, and then reviews two common types of melanin inhibitors, namely tyrosinase synthesis inhibitors and tyrosinase inhibitors derived from natural products and traditional Chinese medicine. This article provides guidance for the development of new melanin inhibitors, and puts forward the idea for combining and synergizing inhibitors according to different mechanisms, in order to develop new whitening formulas.
Biological Products ; Enzyme Inhibitors ; Humans ; Medicine, Chinese Traditional ; Melanins ; Monophenol Monooxygenase