The Inhibitory Effect of Curcumin Derivative J147 on Melanogenesis and Melanosome Transport by Facilitating ERK-Mediated MITF Degradation

Establishment of an in vitro cell coculture model for investigating the whitening mechanism of Paeonia lactiflora Pall seeds oil

BACKGROUND

In vitro single-cell experiments may yield inconsistent results compared to clinical trials. To enhance the reliability of cosmetic active ingredient screening, a coculture model of B16F10-HaCaT cells was established in vitro based on the structural characteristics of human skin, thereby improving the credibility of experimental outcomes. Currently, most cosmetic whitening additives primarily target simple efficacy goals such as inhibiting tyrosinase activity or melanin transfer. Therefore, investigating novel and efficient whitening additives has become a prominent research focus.

OBJECTIVES

The aim is to establish an in vitro cell coculture model for more reliable experimental results and investigate the mechanism by which Paeonia lactiflora Pall seeds oil inhibits melanin production and transfer.

METHODS

The impact of different concentrations of Paeonia lactiflora Pall seeds oil on cocultured cell proliferation rate was assessed using cck8 assay. Tyrosinase inhibition ability in cocultured cells was tested using levodopa as a substrate. Melanin production inhibition ability in coculture cells was evaluated by lysing cells with sodium hydroxide. The effect of Paeonia lactiflora Pall seeds oil on dendrite-related gene expression levels was examined through qPCR analysis. Additionally, Western blotting was employed to study the effect of Paeonia lactiflora Pall seeds oil on dendrite-related protein expression levels.

RESULTS

Different concentrations of Paeonia lactiflora Pall seeds oil did not affect the proliferation activity of cocultured cells. A specific concentration of α-MSH increased cell tyrosinase activity, cellular melanin content, as well as Rac1, Cdc42, and PAR-2 gene and protein expression related to dendritic formation. Treatment with a certain concentration of Paeonia lactiflora Pall seeds oil resulted in decreased tyrosinase activity and melanin content in cells along with downregulated expression levels of Rac1, Cdc42, and PAR-2 genes and proteins associated with dendritic formation.

CONCLUSIONS

Paeonia lactiflora Pall seeds oil at specific concentrations exhibits the ability to inhibit tyrosinase activity, decrease melanin content, and possesses the potential to impede melanin transfer.

Germacrone, isolated from Curcuma wenyujin, inhibits melanin synthesis through the regulation of the MAPK signaling pathway

Abnormal melanin synthesis causes hyperpigmentation disorders, such as chloasma, freckles, and melanoma, which are highly multiple and prevalent. There were few reports on the anti-melanogenic effect of Curcuma wenyujin Y.H. Chen et C. Ling, and the bioactive compound has not been elucidated as well. The study aims to investigate the anti-melanogenic effect of C. wenyujin, and identify the bioactive compound, and further explore its underlying mechanism. Our results showed that the Petroleum ether fraction extracted from C. wenyujin rhizome had a significant anti-melanogenic effect, and germacrone isolated from it was confirmed as the major bioactive compound. To our data, germacrone significantly inhibited tyrosinase (TYR) activity, reduced melanosome synthesis, reduced dendrites formation of B16F10 cells, and melanosome transport to keratinocytes. Moreover, germacrone effectively decreased the hyperpigmentation in zebrafish and the skin of guinea pigs in vivo. Western-blot analysis showed that germacrone down-regulated the expression of TYR, TRP-1, TRP-2, Rab27a, Cdc42, and MITF proteins via the activation of the MAPK signaling pathway. Taken together, germacrone is an effective bioactive compound for melanogenesis inhibition. Our studies suggest that germacrone may be considered a potential candidate for skin whitening.

The inhibition of VDAC1 oligomerization promotes pigmentation through the CaMK-CRTCs/CREB-MITF pathway

The voltage-dependent anion channel 1 (VDAC1) forms an oligomeric structure on the mitochondrial outer membrane, which plays critical roles in many physiological processes. Research studies have demonstrated that the knockout of VDAC1 increases pigment content and up-regulates the expression of melanogenic genes. Due to its involvement in various physiological processes, the depletion of VDAC1 has significant detrimental effects on cellular functions and the inhibition of VDAC1 oligomerization has recently emerged as a promising strategy for the treatment of several diseases. In this study, we found that VDAC1 oligomerization inhibitors, VBIT-12 and NSC-15364, promote melanogenesis, dendrite formation and melanosome transport in human epidermal melanocytes (HEMCs). Mechanistically, treatment of HEMCs with an oligomerization inhibitor increased the level of cytoplasmic calcium ions, which activated calcium-calmodulin dependent protein kinase (CaMK) and led to the phosphorylation of CREB and the nuclear translocation of CREB-regulated transcription coactivators (CRTCs). Subsequently, CRTCs, p-CREB and CREB-binding protein (CBP) in the nucleus cooperatively recruit the transcription machinery to initiate the transcription of MITF thus promoting pigmentation. Importantly, our study also demonstrates that VDAC1 oligomerization inhibitors increase pigmentation in zebrafish and in human skin explants, highlighting their potential as a therapeutic strategy for skin pigmentation disorders.

J147 affects cognition and anxiety after surgery in Zucker rats

Vulnerable patients are at risk for neuroinflammation-mediated post-operative complications, including depression (POD) and cognitive dysfunction (POCD). Zucker rats, expressing multiple risk factors for post-operative complications in humans, may provide a clinically relevant model to study pathophysiology and explore potential interventions. J147, a newly developed anti-dementia drug, was shown to prevent POCD in young healthy rats, and improved early post-surgical recovery in Zucker rats. Aim of the present study was to investigate POCD and the therapeutic potential of J147 in male Zucker rats. Risk factors in the Zucker rat strain were evaluated by comparison with lean littermates. Zucker rats were subjected to major abdominal surgery. Acute J147 treatment was provided by a single iv injection (10 mg/kg) at the start of surgery, while chronic J147 treatment was provided in the food (aimed at 30 mg/kg/day), starting one week before surgery and up to end of protocol. Effects on behavior were assessed, and plasma, urine and brain tissue were collected and processed for immunohistochemistry and molecular analyses. Indeed, Zucker rats displayed increased risk factors for POCD, including obesity, high plasma triglycerides, low grade systemic inflammation, impaired spatial learning and decreased neurogenesis. Surgery in Zucker rats reduced exploration and increased anxiety in the Open Field test, impaired short-term spatial memory, induced a shift in circadian rhythm and increased plasma neutrophil gelatinase-associated lipocalin (NGAL), microglia activity in the CA1 and blood brain barrier leakage. Chronic, but not acute J147 treatment reduced anxiety in the Open Field test and protected against the spatial memory decline. Moreover, chronic J147 increased glucose sensitivity. Acute J147 treatment improved long-term spatial memory and reversed the circadian rhythm shift. No anti-inflammatory effects were seen for J147. Although Zucker rats displayed risk factors, surgery did not induce extensive POCD. However, increased anxiety may indicate POD. Treatment with J147 showed positive effects on behavioral and metabolic parameters, but did not affect (neuro)inflammation. The mixed effect of acute and chronic treatment may suggest a combination for optimal treatment.

Current evidence for J147 as a potential therapeutic agent in nervous system disease: a narrative review

Curcumin has anti-inflammatory, antioxidant, and anticancer effects and is used to treat diseases such as dermatological diseases, infection, stress, depression, and anxiety. J147, an analogue of curcumin, is designed and synthesized with better stability and bioavailability. Accumulating evidence demonstrates the potential role of J147 in the prevention and treatment of Alzheimer's disease, diabetic neuropathy, ischemic stroke, depression, anxiety, and fatty liver disease. In this narrative review, we summarized the background and biochemical properties of J147 and discussed the role and mechanism of J147 in different diseases. Overall, the mechanical attributes of J147 connote it as a potential target for the prevention and treatment of neurological diseases.

Targeting Tyrosinase in Hyperpigmentation: Current Status, Limitations and Future Promises

Hyperpigmentation is a common and distressing dermatologic condition. Since tyrosinase (TYR) plays an essential role in melanogenesis, its inhibition is considered a logical approach along with other therapeutic methods to prevent the accumulation of melanin in the skin. Thus, TYR inhibitors are a tempting target as the medicinal and cosmetic active agents of hyperpigmentation disorder. Among TYR inhibitors, hydroquinone is a traditional lightening agent that is commonly used in clinical practice. However, despite good efficacy, prolonged use of hydroquinone is associated with side effects. To overcome these shortcomings, new approaches in targeting TYR and treating hyperpigmentation are desperately requiredessentialneeded. In line with this purpose, several non-hydroquinone lightening agents have been developed and suggested as hydroquinone alternatives. In addition to traditional approaches, nanomedicine and nanotheranostic platforms have been recently proposed in the treatment of hyperpigmentation. In this review, we discuss the available strategies for the management of hyperpigmentation with a focus on TYR inhibition. In addition, alternative treatment options to hydroquinone are discussed. Finally, we present nano-based strategies to improve the therapeutic effect of drugs prescribed to patients with skin disorders.

Cryptochrome 1 activation inhibits melanogenesis and melanosome transport through negative regulation of cAMP/PKA/CREB signaling pathway

Cutaneous pigmentation was recently shown to be an event regulated by clock proteins. Cryptochrome (CRY) is a key protein composing the feedback loop of circadian clock, however, the function of CRY in melanocytes remains unclear. Here, we found that KL001, a synthetic small molecule modulator of CRY1, inhibited melanin synthesis, as well as reduced melanocyte dendrite elongation and melanosome transport. In addition, the dominant role of CRY1 in KL001-induced anti-melanogenesis was revealed by small interfering RNA transfection. Cellular tyrosinase activity and expression level of melanogenic proteins, including tyrosinase, TRP-1, TRP-2, and transport proteins like Rab27a, Cdc42 and Myosin Va induced by α-MSH were remarkably reversed after KL001 treatment. Mechanistically, CRY1 activation inhibited melanogenesis through CREB-dependent downregulation of MITF and CREB phosphorylation was mediated by classical cAMP/PKA pathway. In addition, the other CRY1 activator, KL044 also suppressed cAMP/PKA/CREB pathway and inhibited melanogenesis. Finally, anti-melanogenic efficacy of KL001 was confirmed by determination of melanin contents in UVB-tanning model of brown guinea pigs, which indicated that targeting CRY1 activity, via topical application of small molecule activator, can be utilized therapeutically to manage human pigmentary disorders.

Vitiligo and Mental Health: Natural Compounds' Usefulness

Vitiligo is an autoimmune dermatosis frequently associated with other comorbidities, such as mental health disorders. It is unclear if vitiligo triggers mental disorders or if mental disorders trigger vitiligo, but each one affects and worsen the other, if present at the same time. Both mental health disorders and vitiligo present a multifactorial pathogenesis and often require prolonged periods of therapy, sometimes with poor results. Given the possible link of common pathogenetic factors and the need of integrated therapies, the aim of this review is to look at natural compounds as possible supplements for both conditions. The results yielded show a possible role of these supplements in ameliorating both conditions, thus helping these patients to achieve a better quality of life and reduce the need for prolonged therapies. The limitations regarding the relative lack of in vivo studies, and the increasing need to lighten the burden of these chronic diseases, suggests that it is mandatory to proceed with further trials.

New Butyroside D from Argan Press Cake Possess Anti-Melanogenesis Effect via MITF Downregulation in B16F10 and HEM Cells

Hyperpigmentation is a skin condition where patches of skin become darker in color due to excess melanin production upon UV exposure leading to melasma, which are lentigines or post inflammatory hyperpigmentation that psychologically affecting a great number of people. The present study investigates the anti-melanogenic effect of Butyroside D and the underling mechanism. After the confirmation of the non-cytotoxic effect of Butyroside D on B16F10 cells, we proceeded with analyzing the impact of the treatment at low and high concentration (i.e., 0.2 μM and 2 μM) using gene profiling analysis and examined the differentiation in gene expression. Our results identify cyclic adenosine monophosphate (cAMP), Wnt/β-catenin and Mitogen-Activated Protein Kinase (MAPK) signaling pathways to be downregulated upon treatment with Butyroside D. These pathways were targeted to further validate the effect of Butyroside D on membrane receptors melanocortin 1 receptor (MC1R) and receptor tyrosine kinase (c-Kit), related microphthalmia-associated transcription factor (MITF) and consequently tyrosinase (TYR), and tyrosine-related protein-1 (TYRP-1) that were all shown to be downregulated and, therefore, leading to the repression of melanin biosynthesis. Finally, the anti-melanogenic effect of Butyroside D was confirmed on human epidermal melanocytes (HEM) cells by inhibiting the activation of cAMP pathway generally mediated through α-melanocyte-stimulating hormone (α-MSH) and MC1R. Overall, this study suggests the potential applicability of this purified compound for the prevention of hyperpigmentation conditions.

Inhibitory activity of soybean (Glycine max L. Merr.) Cell Culture Extract on tyrosinase activity and melanin formation in alpha-melanocyte stimulating Hormone-Induced B16-F10 melanoma cells

BACKGROUND

Hyperpigmentation, which causes excessive melanin synthesis and accumulation, is an important issue in the cosmetic industry. Since compounds developed against hyperpigmentation often come with side effects such as skin irritation and contact dermatitis, new studies focus on the use of natural agents that have no side effects.

METHODS AND RESULTS

In this study, it was found that the effects of soybean cell culture extract (SCE) on alpha-melanocyte-stimulating hormone (α-MSH) induced melanogenesis in B16-F10 murine melanoma cells. The cells were incubated with SCE for 48 h after treatment with α‑MSH for 24 h to analysis the melanin content, cellular tyrosinase activity, and gene and protein expression. SCE at 1 mg/mL decreased melanin content and tyrosinase activity by 34% and 24%, respectively, compared to the α-MSH-treated group, which did not decrease cell viability. In addition, SCE (1 mg/mL) downregulated the expression of tyrosinase (TYR), tyrosinase-related protein (TRP)-1, tyrosinase-related protein (TRP)-2, and microphthalmia-associated transcription factor (MITF) genes 1.5-, 1.5-, 2-, and 2-fold, respectively. Furthermore, SCE inhibited the expression of TYR, TRP1, and TRP2 by decreasing the expression of MITF, as shown in a western blot assay.

CONCLUSIONS

This study suggests that SCE reveals dose-dependent inhibition of melanin synthesis through the suppression of tyrosinase activity as well as molecular levels of TYR, TRP1, TRP2, and MITF in B16-F10 murine melanoma cells. Therefore, SCE has the potential to be an effective and natural skin-whitening agent for application in the cosmetic industry.