Amine derivatives of furocoumarin induce melanogenesis by activating Akt/GSK-3β/β-catenin signal pathway

Decreased ZMIZ1 suppresses melanogenesis in vitiligo by regulating mTOR/AKT/GSK-3β-mediated glucose uptake

The loss of epidermal melanocytes is a distinguishing feature of vitiligo (VIT), a prevalent and long-lasting skin ailment. While various hypotheses exist to explain the cause of VIT, the precise mechanisms leading to this disease remain unclear. Zinc finger MIZ-type containing 1 (ZMIZ1) has a strong link with the development and occurrence of VIT. However, the exact role of ZMIZ1 and its underlying mechanisms in VIT are not well understood. Our study aims to illustrate that targeting ZMIZ1 is an effective therapeutic and prophylactic strategy for treating VIT. We obtained the RNA expression profile of VIT samples using RNA-seq and determined the locations and expression of ZMIZ1 in these samples via immunochemistry. Glucose uptake was analyzed through immunofluorescence and glucose uptake assay. We evaluated mRNA levels using qPCR and used plasmids transfection to knock down ZMIZ1 in PIG1 and PIG3V cell lines. The activation of the mTOR/AKT/GSK-3β signalling pathway was assessed using Western blotting analysis. We found that ZMIZ1 expression was decreased in VIT samples. Decreased ZMIZ1 expression inhibits the proliferation, migration, and invasion of melanocytes in vitro. Moreover, we revealed that decreased ZMIZ1 could also inhibit the glucose uptake of melanocytes in vitro. Decreased ZMIZ1 expression inhibits the activation of the mTOR/AKT/GSK-3β pathway and the expression of melanin synthesis-related proteins in melanocytes. Finally, we demonstrated that decreased ZMIZ1 may inhibit the cell viability of melanocytes and the synthesis of melanin by mTOR/AKT/GSK-3β-mediated oxidative stress in vitro. In conclusion, our study suggests that decreased ZMIZ1 suppresses melanogenesis in vitiligo by regulating the mTOR/AKT/GSK-3β-mediated glucose uptake in vitro, making ZMIZ1 an attractive therapeutic target for the treatment of VIT.

A Systematic Study of Yiqi Qubai Standard Decoction for Treating Vitiligo Based on UPLC-Q-TOF/MS Combined with Chemometrics, Molecular Docking, and Cellular and Zebrafish Assays

The Yiqi Qubai (YQ) formula is a hospital preparation for treating vitiligo in China that has had reliable efficacy for decades. The formula consists of four herbs; however, the extraction process to produce the formula is obsolete and the active ingredients and mechanisms remain unknown. Therefore, in this paper, fingerprints were combined with the chemometrics method to screen high-quality herbs for the preparation of the YQ standard decoction (YQD). Then, the YQD preparation procedure was optimized using response surface methodology. A total of 44 chemical constituents, as well as 36 absorption components (in rat plasma) of YQD, were identified via UPLC-Q-TOF/MS. Based on the ingredients, the quality control system of YQD was optimized by establishing the SPE-UPLC-Q-TOF/MS identification method and the HPLC quantification method. Network pharmacological analysis and molecular docking showed that carasinaurone, calycosin-7-O-β-d-glucoside, methylnissolin-3-O-glucoside, genkwanin, akebia saponin D, formononetin, akebia saponin B, and apigenin may be the key active components for treating vitiligo; the core targets associated with them were AKT1, MAPK1, and mTOR, whereas the related pathways were the PI3K-Akt, MAPK, and FoxO signaling pathways. Cellular assays showed that YQD could promote melanogenesis and tyrosinase activity, as well as the transcription and expression of tyrosinase-associated proteins (i.e., TRP-1) in B16F10 cells. In addition, YQD also increased extracellular tyrosinase activity. Further efficacy validation showed that YQD significantly promotes melanin production in zebrafish. These may be the mechanisms by which YQD improves the symptoms of vitiligo. This is the first systematic study of the YQ formula that has optimized the standard decoction preparation method and investigated the active ingredients, quality control, efficacy, and mechanisms of YQD. The results of this study lay the foundations for the clinical application and further development of the YQ formula.

Phenolic acids in Panax ginseng inhibit melanin production through bidirectional regulation of melanin synthase transcription via different signaling pathways

Background

Our previous investigation indicated that the preparation of Panax ginseng Meyer (P. ginseng) inhibited melanogenesis. It comprised salicylic acid (SA), protocatechuic acid (PA), p-coumaric acid (p-CA), vanillic acid (VA), and caffeic acid (CA). In this investigation, the regulatory effects of P. ginseng phenolic acid monomers on melanin production were assessed.

Methods

In vitro and in vivo impact of phenolic acid monomers were assessed.

Results

SA, PA, p-CA and VA inhibited tyrosinase (TYR) to reduce melanin production, whereas CA had the opposite effects. SA, PA, p-CA and VA significantly downregulated the melanocortin 1 receptor (MC1R), cycle AMP (cAMP), protein kinase A (PKA), cycle AMP-response element-binding protein (CREB), microphthalmia-associated transcription factor (MITF) pathway, reducing mRNA and protein levels of TYR, tyrosinase-related protein 1 (TYRP1), and TYRP2. Moreover, CA treatment enhanced the cAMP, PKA, and CREB pathways to promote MITF mRNA level and phosphorylation. It also alleviated MITF protein level in α-MSH-stimulated B16F10 cells, comparable to untreated B16F10, increasing the expression of phosphorylation glycogen synthase kinase 3β (p-GSK3β), β-catenin, p-ERK/ERK, and p-p38/p38. Furthermore, the GSK3β inhibitor promoted p-GSK3β and p-MITF expression, as observed in CA-treated cells. Moreover, p38 and ERK inhibitors inhibited CA-stimulated p-p38/p38, p-ERK/ERK, and p-MITF increase, which had negative binding energies with MC1R, as depicted by molecular docking.

Conclusion

P. ginseng roots' phenolic acid monomers can safely inhibit melanin production by bidirectionally regulating melanin synthase transcription. Furthermore, they reduced MITF expression via MC1R/cAMP/PKA signaling pathway and enhanced MITF post-translational modification via Wnt/mitogen-activated protein kinase signaling pathway.

The PI3K-Akt-mTOR and Associated Signaling Pathways as Molecular Drivers of Immune-Mediated Inflammatory Skin Diseases: Update on Therapeutic Strategy Using Natural and Synthetic Compounds

The dysregulated phosphatidylinositol-3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) signaling pathway has been implicated in various immune-mediated inflammatory and hyperproliferative dermatoses such as acne, atopic dermatitis, alopecia, psoriasis, wounds, and vitiligo, and is associated with poor treatment outcomes. Improved comprehension of the consequences of the dysregulated PI3K/Akt/mTOR pathway in patients with inflammatory dermatoses has resulted in the development of novel therapeutic approaches. Nonetheless, more studies are necessary to validate the regulatory role of this pathway and to create more effective preventive and treatment methods for a wide range of inflammatory skin diseases. Several studies have revealed that certain natural products and synthetic compounds can obstruct the expression/activity of PI3K/Akt/mTOR, underscoring their potential in managing common and persistent skin inflammatory disorders. This review summarizes recent advances in understanding the role of the activated PI3K/Akt/mTOR pathway and associated components in immune-mediated inflammatory dermatoses and discusses the potential of bioactive natural products, synthetic scaffolds, and biologic agents in their prevention and treatment. However, further research is necessary to validate the regulatory role of this pathway and develop more effective therapies for inflammatory skin disorders.

A 7-Hydroxy 4-Methylcoumarin Enhances Melanogenesis in B16-F10 Melanoma Cells

The objectives of this study were to investigate the melanogenetic potentials of the naturally occurring 7-hydroxy coumarin derivatives 7-hydroxy 5,6-dimethoxycoumarin (7H-5,6DM), 7-hydroxy 6,8-dimethoxycoumarin (7H-6,8DM), 7-hydroxy 6-methoxycoumarin (7H-6M), and 7-hydroxy 4-methylcoumarin (7H-4M) in the melanogenic cells model for murine B16F10 melanoma cells. The initial results indicated that melanin production and intracellular tyrosinase activity were significantly stimulated by 7H-4M but not by 7H-5,6DM, 7H-6,8DM, or 7H-6M. Therefore, our present study further investigated the melanogenic effects of 7H-4M in B16-F10 cells, as well as its mechanisms of action. In a concentration-dependent manner, 7H-4M increased intracellular tyrosinase activity, leading to the accumulation of melanin without affecting the viability of B16-F10 cells. Our study further investigated the effects of 7H-4M on melanogenesis, including its ability to promote tyrosinase activity, increase melanin content, and activate molecular signaling pathways. The results indicate that 7H-4M effectively stimulated tyrosinase activity and significantly increased the expression of melanin synthesis-associated proteins, such as microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP1), and TRP2. Based on our findings, we can conclude that 7H-4M has the ability to activate the melanogenesis process through the upregulation of cAMP-dependent protein kinase (PKA) and the cAMP response element-binding protein (CREB). Additionally, our study showed that 7H-4M induced melanogenic effects by downregulating the extracellular signal-regulated kinase (ERK) and the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt)/glycogen synthesis kinase-3β (GSK-3β) cascades, while upregulating the JNK and p38 signaling pathways. Finally, the potential of using 7H-4M in topical applications was tested through primary human skin irritation tests. During these tests, no adverse reactions were induced by 7H-4M. In summary, our results indicate that 7H-4M regulates melanogenesis through various signaling pathways such as GSK3β/β-catenin, AKT, PKA/CREB, and MAPK. These findings suggest that 7H-4M has the potential to prevent the development of pigmentation diseases.

Quercetin 3-O-(6″-O-E-caffeoyl)-β-D-glucopyranoside, a Flavonoid Compound, Promotes Melanogenesis through the Upregulation of MAPKs and Akt/GSK3β/β-Catenin Signaling Pathways

Quercetin 3-O-(6″-O-E-caffeoyl)-β-D-glucopyranoside is a flavonoid compound produced by various plants with reported antiprotozoal potential against E. histolytica and G. lamblia; however, its effects on skin pigment regulation have not been studied in detail. In this investigation, we discovered that quercetin 3-O-(6″-O-E-caffeoyl)-D-glucopyranoside (coded as CC7) demonstrated a more increased melanogenesis effect in B16 cells. CC7 exhibited no cytotoxicity or effective stimulating melanin content or intracellular tyrosinase activity. This melanogenic-promoting effect was accompanied by activated expression levels of microphthalmia-associated transcription factor (MITF), a key melanogenic regulatory factor, melanogenic enzymes, and tyrosinase (TYR) and tyrosinase-related protein-1 (TRP-1) and 2 (TRP-2) in the CC7-treated cells. Mechanistically, we found that CC7 exerted melanogenic effects by upregulating the phosphorylation of stress-regulated protein kinase (p38) and c-Jun N-terminal kinase (JNK). Moreover, the CC7 upregulation of phosphor-protein kinase B (Akt) and Glycogen synthase kinase-3 beta (GSK-3β) increased the content of β-catenin in the cell cytoplasm, and subsequently, it translocated into the nucleus, resulting in melanogenesis. Specific inhibitors of P38, JNK, and Akt validated that CC7 promotes melanin synthesis and tyrosinase activity by regulating the GSK3β/β-catenin signaling pathways. Our results support that the CC7 regulation of melanogenesis involves MAPKs and Akt/GSK3β/β-catenin signaling pathways.

Research Progress of Small Molecules as Anti-vitiligo Agents

Vitiligo is a disease characterized by skin discoloration, and no safe and effective drugs have been developed until now. New drug research and development are imminent. This article reviews the research on small-molecule drugs for vitiligo from 1990 to 2021 at home and abroad. They are classified according to their structures and mechanisms of action, including natural products and derivatives, anti-oxidative stress drugs, immunosuppressants, prostaglandins, etc. The research on their anti-vitiligo activity, structural modification, new dosage forms, clinical trials, and the development trend in new anti-vitiligo drugs are reviewed, which provides important references for the development of new drugs.

Anti-Melanogenesis Effect of Polysaccharide from Saussurea involucrata on Forskolin-Induced Melanogenesis in B16F10 Melanoma Cells

As one of the prominent medicinal plants listed in the Chinese pharmacopoeia (2020), Saussurea involucrata (Kar. et Kir.) Sch.-Bip was demonstrated to possess various therapeutic effects. In our recent research, we extracted the polysaccharides from S. involucrata (SIP) at optimal conditions and conducted further structure elucidation on the main fraction as well as the confirmation of its possible anti-inflammatory activity. Hence, in this work, we assessed the in vitro antioxidant activity and anti-melanogenesis effects of the crude SIP in forskolin-induced B16F10 melanoma cells. The results show that SIP possessed strong antioxidant activity and was effective in concentration-dependently decreasing melanin formation and inhibiting tyrosinase activity in forskolin-induced B16F10 cells. Based on these results, the inhibitory mechanism of melanogenesis was investigated by measuring Tyrosinase (TYR), Tyrosinase related protein-1 (TRP-1), Tyrosinase related protein-2 (TRP-2), Microphthalmia-associated transcription factor (MITF), cAMP-response element binding protein (CREB), mitogen-activated protein kinases (MAPK) signaling protein members, and β-catenin degradation in forskolin-induced B16F10 cells. The anti-melanogenesis response of SIP might be attributed to the regulation of c-Jun N-terminal kinase (JNK) phosphorylation and β-catenin degradation pathways. These results suggest that polysaccharides from S. involucrata possess a strong anti-melanogenic effect, and thus could be used as a high-value natural material for skin whitening in cosmeceutical industries.

A Novel Furocoumarin Derivative, 5-((diethylamino)me-13 thyl)-3-phenyl-7H-furo [3,2-g] chromen-7-one Upregulates Melanin Synthesis via the Activation of cAMP/PKA and MAPKs Signal Pathway: In Vitro and In Vivo Study

Psoralen, a major furocoumarin component of the Fructus Psoralen (FP), in combination with ultraviolet radiation, cures abnormal pigmentation disorder. In a previous study, we synthesized a series of linear furocoumarins with different substituents, out of which 5-((diethylamino)methyl)-3-phenyl-7H-furo [3,2-g] chromen-7-one (encoded as 5D3PC) showed better pigmenting effect than others in B16 cells. In this study, we examined the mechanism underlying the melanogenic effect of 5D3PC both in vivo and in vitro. To examine the pigmentation effect, the B16 and human melanocyte cell lines, PIG1 and PIG3V melanocytes were incubated with 5D3PC. In animal experiments, C57BL/6 mice received 5% hydroquinone and were administrated with 5D3PC for 30 days. 5D3PC upregulated the melanin synthesis and tyrosinase in B16 cell, PIG1 and PIG3V. The expression level of tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1) and tyrosinase-related protein-2 (TRP-2), microphthalmia-associated transcription factor (MITF), cyclic adenosine monophosphate (cAMP), phosphorylation of cAMP-responsive element binding protein (p-CREB), phosphorylation of p38 mitogen-activated protein kinase (MAPK), c- phosphorylation of Jun N-terminal kinase (p-JNK) was significantly higher in 5D3PC-treated B16 cells. The oral administration of 5D3PC attenuated the depigmentation of the C57BL/6 vitiligo mice model by increasing the numbers of melanin-containing hair follicles, melanogenic protein, and melanogenesis-relative genes expression in skin tissues.

Imperatorin Positively Regulates Melanogenesis through Signaling Pathways Involving PKA/CREB, ERK, AKT, and GSK3β/β-Catenin

The present study investigated the melanogenic effects of imperatorin and isoimperatorin and the underlying mechanisms of imperatorin using a mouse melanoma B16F10 model. Interestingly, treatment with 25 μM of either imperatorin or isoimperatorin, despite their structural differences, did not produce differences in melanin content and intracellular tyrosinase activity. Imperatorin also activated the expression of melanogenic enzymes, such as tyrosinase (TYR) and tyrosinase-related proteins TYRP-1 and TYRP-2. Mechanistically, imperatorin increases melanin synthesis through the cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA)/cAMP-responsive element-binding protein (CREB)-dependent upregulation of microphthalmia-associated transcription factor (MITF), which is a key transcription factor in melanogenesis. Furthermore, imperatorin exerted melanogenic effects by downregulating extracellular signal-regulated kinase (ERK) and upregulating phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT)/glycogen synthesis kinase-3β (GSK-3β). Moreover, imperatorin increased the content of β-catenin in the cell cytoplasm and nucleus by reducing the content of phosphorylated β-catenin (p-β-catenin). Finally, we tested the potential of imperatorin in topical application through primary human skin irritation tests. These tests were performed on the normal skin (upper back) of 31 volunteers to determine whether 25 or 50 µM of imperatorin had irritation or sensitization potential. During these tests, imperatorin did not induce any adverse reactions. Taken together, these findings suggest that the regulation of melanogenesis by imperatorin can be mediated by signaling pathways involving PKA/CREB, ERK, AKT, and GSK3β/β-catenin and that imperatorin could prevent the pathogenesis of pigmentation diseases when used as a topical agent.

BCI-215, a Dual-Specificity Phosphatase Inhibitor, Reduces UVB-Induced Pigmentation in Human Skin by Activating Mitogen-Activated Protein Kinase Pathways

Background: The dysregulation of melanin production causes skin-disfiguring ultraviolet (UV)-associated hyperpigmented spots. Previously, we found that the activation of c-Jun N-terminal kinase (JNK), a mitogen-activated protein kinase (MAPK), inhibited melanogenesis. Methods: We selected BCI-215 as it may modify MAPK expression via a known function of a dual-specificity phosphatase (DUSP) 1/6 inhibitor. B16F10 melanoma cells, Mel-ab cells, human melanocytes, and a coculture were used to assess the anti-melanogenic activity of BCI-215. The molecular mechanisms were deciphered by assaying the melanin content and cellular tyrosinase activity via immunoblotting and RT-PCR. Results: BCI-215 was found to suppress basal and cAMP-stimulated melanin production and cellular tyrosinase activity in vitro through the downregulation of microphthalmia-associated transcription factor (MITF) protein and its downstream enzymes. The reduction in MITF expression caused by BCI-215 was found to be due to all three types of MAPK activation, including extracellular signal-regulated kinase (ERK), JNK, and p38. The degree of activation was greater in ERK. A phosphorylation of the β-catenin pathway was also demonstrated. The melanin index, expression of MITF, and downstream enzymes were well-reduced in UVB-irradiated ex vivo human skin by BCI-215. Conclusions: As BCI-215 potently inhibits UV-stimulated melanogenesis, small molecules of DUSP-related signaling modulators may provide therapeutic benefits against pigmentation disorders.

Mechanistic Insights into the Ameliorating Effect of Melanogenesis of Psoralen Derivatives in B16F10 Melanoma Cells

The objectives of this study were to investigate the melanogenetic potential of the psoralen derivatives 5-hydroxypsoralen, 5-methoxypsoralen, 8-hydroxypsoralen, 8-methoxypsoralen, and 5,8-dimethoxypsoralen in B16F10 melanoma cells. The results indicated that melanin production is significantly stimulated in B16F10 melanoma cells with 5-methoxypsoralen, 8-methoxypsoralen, and 5,8-dimethoxypsoralen, especially for 5-methoxypsoralen (bergapten), as reported previously. In addition, Western blot results showed that the protein levels of microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2 (TRP-2) increase after bergapten treatment for the first time. The results also showed that bergapten promotes the phosphorylation of Akt at Ser 473 and glycogen synthase kinase-3β at Ser 9. Moreover, bergapten increased the content of β-catenin in the cell cytoplasm and nucleus by reducing the phosphorylated β-catenin (p-β-catenin) content. The results also indicated that bergapten regulates melanogenesis by upregulating the phosphorylation of p38 and JNK-mitogen-activated protein kinase. Taken together, these findings suggest that the regulation of melanogenesis by bergapten may be mediated by the β-catenin and MAPK signaling pathways and that bergapten might provide new insights into the pathogenesis of pigmented diseases.

Discovery of small-molecule modulators of melanogenesis by docking-based virtual screening

Background: Vitiligo is a relatively common depigmenting skin disorder. UV light stimulation is often used to obtain repigmentation. Wnt signaling regulates melanocyte differentiation, and expression of TYR is upregulated in narrow-band UVB-treated epidermis. Manipulation of these two pathways by drugs could serve as one of the therapeutic approaches for durable repigmentation. Methods and results: CD9 was identified as a novel TYR activator by virtual screening and bioactivity assay. CD9 activated the Wnt signaling pathway through triggering translocation of β-catenin from cytoplasm to nucleus. Conclusion: The pathogenesis of vitiligo is complicated and varies with each individual, so combination therapy may be much more suitable for treatment of vitiligo. CD9 could synergize with other anti-inflammatory compounds or autoimmune suppressors to shorten repigmentation time and improve efficacy.

Plant-Derived Compounds as Promising Therapeutics for Vitiligo

Vitiligo is the most common depigmenting disorder characterized by white patches in the skin. The pathogenetic origin of vitiligo revolves around autoimmune destruction of melanocytes in which, for instance, oxidative stress is responsible for melanocyte molecular, organelle dysfunction and melanocyte specific antigen exposure as well as melanocyte cell death and thus serves as an important contributor for vitiligo progression. In recent years, natural products have shown a wide range of pharmacological bioactivities against many skin diseases, and this review focuses on the effects and mechanisms of natural compounds against vitiligo models. It is showed that some natural compounds such as flavonoids, phenols, glycosides and coumarins have a protective role in melanocytes and thereby arrest the depigmentation, and, additionally, Nrf2/HO-1, MAPK, JAK/STAT, cAMP/PKA, and Wnt/β-catenin signaling pathways were reported to be implicated in these protective effects. This review discusses the great potential of plant derived natural products as anti-vitiligo agents, as well as the future directions to explore.

LATS1 Is a Mediator of Melanogenesis in Response to Oxidative Stress and Regulator of Melanoma Growth

The LATS1 kinase has been described as a tumor suppressor in various cancers. However, its role in melanoma has not been fully elucidated. There are several processes involved in tumorigenesis, including melanin production. Melanin content positively correlates with the level of reactive oxygen species (ROS) inside the cell. Accordingly, the purpose of the study was to assess the role of LATS1 in melanogenesis and oxidative stress and its influence on tumor growth. We have knocked down LATS1 in primary melanocytes and melanoma cells and found that its expression is crucial for melanin synthesis, ROS production, and oxidative stress response. We showed that LATS1 ablation significantly decreased the melanogenesis markers' expression and melanin synthesis in melanocyte and melanoma cell lines. Moreover, silencing LATS1 resulted in enhanced oxidative stress. Reduced melanin content in LATS1 knocked down tumors was associated with increased tumor growth, pointing to melanin's protective role in this process. The study demonstrated that LATS1 is highly engaged in melanogenesis and oxidative stress control and affects melanoma growth. Our results may find the implications in the diagnosis and treatment of pigmentation disorders, including melanoma.

Astragaloside IV Enhances Melanogenesis via the AhR-Dependent AKT/GSK-3β/β-Catenin Pathway in Normal Human Epidermal Melanocytes

Astragalus membranaceus root has been widely used for repigmentation treatment in vitiligo, but its mechanism is poorly understood. We sought to investigate the effect of astragaloside IV (AS-IV), a main active extract of the Astragalus membranaceus root, on melanin synthesis in normal human epidermal melanocytes (NHEMs) and to elucidate its underlying mechanisms. Melanin content, tyrosinase activity, qPCR, western blot, and immunofluorescence were employed. Specific inhibitors and small interfering RNA were used to investigate the possible pathway. AS-IV stimulated melanin synthesis and upregulated the expression of melanogenesis-related genes in a concentration-dependent manner in NHEMs. AS-IV could activate the aryl hydrocarbon receptor (AhR), and AS-IV-induced melanogenesis was inhibited in si-AhR-transfected NHEMs. In addition, we showed that AS-IV enhanced the phosphorylation of AKT and GSK-3β and nuclear translocation of β-catenin. AS-IV-induced MITF expression upregulation and melanin synthesis were decreased in the presence of β-catenin inhibitor FH353. Furthermore, AhR antagonist CH223191 inhibited the activation of AKT/GSK-3β/β-catenin signaling, whereas the expression of CYP1A1 (marker of AhR activation) was not affected by the AKT inhibitor in AS-IV-exposed NHEMs. Our findings show that AS-IV induces melanogenesis through AhR-dependent AKT/GSK-3β/β-catenin pathway activation and could be beneficial in the therapy for depigmented skin disorders.

Suppression of FADS1 induces ROS generation, cell cycle arrest, and apoptosis in melanocytes: implications for vitiligo

Vitiligo is a potentially serious condition characterized by loss of melanin and death of melanocytes. To identify potential therapeutic targets for vitiligo, we conducted a microarray analysis of three human vitiligo specimens and paired adjacent normal tissues. Because we found that the fatty acid desaturase 1 (FADS1) gene was downregulated in vitiligo specimens, we carried out experiments to assess its role in melanocyte replication and survival. RT-qPCR was used to verify that FADS1 expression was lower in vitiligo-affected tissues and vitiligo melanocyte PIG3V cells than in matched controls or normal human epidermal PIG1 melanocytes. In addition, CCK-8, immunofluorescence, western blot and flow cytometry assay were used to detect the proliferation and apoptosis in PIG1 cells respectively. Overexpression of FADS1 promoted proliferation of PIG3V melanocytes, while FADS1 silencing inhibited proliferation and induced cell death in PIG1 melanocytes. Increased ROS generation; induction of mitochondrial-mediated apoptosis via upregulation of Bax and active caspases 3 and 9 and downregulation of Bcl-2; and cell cycle arrest via downregulation of c-Myc and Cyclin D1 and upregulation of p21 were all enhanced after FADS1 silencing in PIG1 melanocytes. These findings implicate FADS1 downregulation in the pathogenesis of vitiligo and may open new avenues for its treatment.