TGF-β2 upregulates tyrosinase activity via Opsin3 in human skin melanocytes in vitro

Transdermal Sustained Release Properties and Anti-Photoaging Efficacy of Liposome-Thermosensitive Hydrogel System

Drug delivery systems have become a research priority in the biomedical field. The incorporation of liposomes to hydrogels further forms more robust multifunctional systems for more effective and sustained topical drug delivery. In this study, carboxymethyl-modified chitosan/hyaluronic acid (CMC/HA, CMH) thermosensitive hydrogel is developed for sustained transdermal delivery of liposomes. Hydrogels are crosslinked by hydrogen bonding, hydrophobic interaction and electrostatic interaction. The gel properties can be regulated by substitution degree (DS), and when DS = 18.20 ± 0.67% (CMH2), the gel temperature is 37.8 °C, allowing rapid gelation at body temperature (315 s). Moreover, CMH2 hydrogel has suitable spreadability (17.7-57.2 cm2 ), viscosity (2133.4 mPa s) and porous structure, which facilitated its adhesion and application on the skin and liposomes delivery. The hydrogel can retard the liposomes release, and the release rate of ascorbyl glucoside (AA2G) is 33.92-49.35% in 24 h. Hydrogel avoids the rapid clearance of liposomes from the skin and improved the skin retention, achieving the long-term release of bioactive components. Liposome-hydrogel system more efficiently promotes the anti-photoaging effect of AA2G on skin, reducing epidermal thickness, melanin deposition and lipid oxidative damage and increasing collagen density. Therefore, liposome-hydrogel systems are proposed as multifunctional delivery systems for sustained transdermal delivery.

In vitro differentiation of human amniotic epithelial stem cells into keratinocytes regulated by OPN3

Human amniotic epithelial stem cells (hAESCs) are regarded as potential alternatives to keratinocytes (KCs) used for skin wound healing. Light is an alternative approach for inducing stem cell differentiation. Opsins (OPNs), a family of light-sensitive, G protein-coupled receptors, play a multitude of light-dependent and light-independent functions in extraocular tissues. However, it remains unclear whether the light sensitivity and function of OPNs are involved in light-induced differentiation of hAESCs to KCs. Herein, we determine the role of OPNs in differentiation of hAESCs into KCs through cell and molecular biology approaches in vitro. It is shown that mRNA expression of OPN3 in the amniotic membrane and hAESCs was higher than the other four primary OPNs by RT-qPCR analysis. Changes in OPN3 gene expression had a significant impact on cell proliferation, stemness and differentiation capability of hAESCs. Furthermore, we found a significant upregulation of OPN3, KRT5 and KRT14 with hAESCs treated at 3 × 33 J/cm2 irradiation from blue-light LED. Taken together, these results suggest that OPN3 acts as a positive regulator of differentiation of hAESCs into KCs. This study provides a novel insight into photosensitive OPNs associated with photobiomodulation(PBM)-induced differentiation in stem cells.

Opsin 3 mediates UVA-induced keratinocyte supranuclear melanin cap formation

Solar ultraviolet (UV) radiation-induced DNA damage is a major risk factor for skin cancer development. UV-induced redistribution of melanin near keratinocyte nuclei leads to the formation of a supranuclear cap, which acts as a natural sunscreen and protects DNA by absorbing and scattering UV radiation. However, the mechanism underlying the intracellular movement of melanin in nuclear capping is poorly understood. In this study, we found that OPN3 is an important photoreceptor in human epidermal keratinocytes and is critical for UVA-mediated supranuclear cap formation. OPN3 mediates supranuclear cap formation via the calcium-dependent G protein-coupled receptor signaling pathway and ultimately upregulates Dync1i1 and DCTN1 expression in human epidermal keratinocytes via activating calcium/CaMKII, CREB, and Akt signal transduction. Together, these results clarify the role of OPN3 in regulating melanin cap formation in human epidermal keratinocytes, greatly expanding our understanding of the phototransduction mechanisms involved in physiological function in skin keratinocytes.

Blue light-emitting diodes for the treatment of localized vitiligo: A retrospective study

BACKGROUND

Vitiligo is an autoimmune dermatological disease characterized by hypopigmented macules. Treatments include topical agents, phototherapy, and laser therapies. Different lasers should be individually chosen regarding location, extent, activity of the disease.

AIMS

This article aims to demonstrate how blue LED is effective and safe, as its wavelength is very close to the UV spectrum (415 nm vs. 400 nm), but, unlike UV therapy, blue LED have not shown any long-term cancerogenic side effects.

PATIENTS/METHODS

We treated 30 patients affected by vitiligo localized on different anatomical areas with blue light-emitting diodes.

RESULTS

Complete repigmentation occurred in 75.33% of treated patients (22 out of 30 patients, 14 males, and 8 females). Partial repigmentation occurred in the remaining patients.

CONCLUSIONS

Blue LED light may be a safe and well-tolerated way to induce repigmentation in patients affected by vitiligo.

Expression of Retinal G Protein-Coupled Receptor, a Member of the Opsin Family, in Human Skin Cells and Its Mediation of the Cellular Functions of Keratinocytes

Background: Photoreceptive proteins play critical physiological roles in human skin cells. The retinal G protein-coupled receptor (RGR) is a photoisomerase in the human retina, but its expression and cellular functions in human skin cells have not been reported.

Objectives: We aimed to detect RGR expression in various skin cells and evaluate its regulation of the cellular functions of keratinocytes.

Methods: The expression, distribution, and subcellular location of the RGR in normal human epidermal keratinocytes and cells with pathological conditions including psoriasis, seborrheic keratosis, and squamous cell carcinoma were determined using microscopic tools (immunohistochemical staining, immunofluorescence staining, and immunoelectron microscopy) and Western blotting (WB). The protein levels of the RGR in primary human melanocytes, keratinocytes, and fibroblasts isolated from the neonatal foreskin were measured by WB. The expression and subcellular localization of the RGR in these cells were detected by immunofluorescence staining under a fluorescence microscope and laser scanning confocal microscope. Additionally, the levels of RGR expression in normal keratinocytes exposed to ultraviolet (UV)-A or total ultraviolet radiation (UVR) in the presence or absence of all-trans-retinal were measured by WB. Furthermore, the effects of the RGR on human keratinocyte functions including proliferation, migration, and apoptosis were evaluated using the Cell Counting Kit 8, wound healing, and Transwell assays after reducing the RGR mRNA level in keratinocytes using small interfering RNA technology.

Results: The RGR was primarily located in the epidermal basal and spinous layers and skin appendages. Its expression increased in psoriatic lesions, seborrheic keratosis, and squamous cell carcinoma. Confocal microscopy showed that the RGR was located in the cell membrane and nucleus of keratinocytes, melanocytes, and fibroblasts. Keratinocytes had a higher expression of the RGR than melanocytes and fibroblasts, as well as nuclear expression, according to nuclear/cytoplasmic fractionation. Colloidal gold immunoelectron microscopy technology further confirmed that the RGR is mainly located in the nucleoplasm and mitochondria and is scattered in the cytoplasm and other organelles in the epidermal keratinocytes. Notably, RGR knockdown in keratinocytes led to the inhibition of cell proliferation and migration, augmenting cell apoptosis.

Conclusions: This study is the first to demonstrate the presence of RGR in the human skin. Our findings indicate that the RGR may play a critical role in the physiological function of epidermal keratinocytes.

The Hypopigmentation Mechanism of Tyrosinase Inhibitory Peptides Derived from Food Proteins: An Overview

Skin hyperpigmentation resulting from excessive tyrosinase expression has long been a problem for beauty lovers, which has not yet been completely solved. Although researchers are working on finding effective tyrosinase inhibitors, most of them are restricted, due to cell mutation and cytotoxicity. Therefore, functional foods are developing rapidly for their good biocompatibility. Food-derived peptides have been proven to display excellent anti-tyrosinase activity, and the mechanisms involved mainly include inhibition of oxidation, occupation of tyrosinase’s bioactive site and regulation of related gene expression. For anti-oxidation, peptides can interrupt the oxidative reactions catalyzed by tyrosinase or activate an enzyme system, including SOD, CAT, and GSH-Px to scavenge free radicals that stimulate tyrosinase. In addition, researchers predict that peptides probably occupy the site of the substrate by chelating with copper ions or combining with surrounding amino acid residues, ultimately inhibiting the catalytic activity of tyrosinase. More importantly, peptides reduce the tyrosinase expression content, primarily through the cAMP/PKA/CREB pathway, with PI3K/AKT/GSK3β, MEK/ERK/MITF and p38 MAPK/CREB/MITF as side pathways. The objective of this overview is to recap three main mechanisms for peptides to inhibit tyrosinase and the emerging bioinformatic technologies used in developing new inhibitors.

Cosmeceutical Therapy: Engaging the Repercussions of UVR Photoaging on the Skin's Circadian Rhythm

Sunlight is an important factor in regulating the central circadian rhythm, including the modulation of our sleep/wake cycles. Sunlight had also been discovered to have a prominent influence on our skin's circadian rhythm. Overexposure or prolonged exposure to the sun can cause skin photodamage, such as the formation of irregular pigmentation, collagen degradation, DNA damage, and even skin cancer. Hence, this review will be looking into the detrimental effects of sunlight on our skin, not only at the aspect of photoaging but also at its impact on the skin's circadian rhythm. The growing market trend of natural-product-based cosmeceuticals as also caused us to question their potential to modulate the skin's circadian rhythm. Questions about how the skin's circadian rhythm could counteract photodamage and how best to maximize its biopotential will be discussed in this article. These discoveries regarding the skin's circadian rhythm have opened up a completely new level of understanding of our skin's molecular mechanism and may very well aid cosmeceutical companies, in the near future, to develop better products that not only suppress photoaging but remain effective and relevant throughout the day.

Integrated analysis of the prognostic and oncogenic roles of OPN3 in human cancers

Background

Emerging cell- or tissue-based evidence has demonstrated that opsin 3 (OPN3) mediates a variety of pathological processes affecting tumorigenesis, clinical prognosis, and treatment resistance in some cancers. However, a comprehensive analysis of OPN3 across human cancers is unavailable. Therefore, a pancancer analysis of OPN3 expression was performed and its potential oncogenic roles were explored.

Methods

The expression and characterization of OPN3 were evaluated among 33 tumour types using The Cancer Genome Atlas (TCGA) dataset. Additionally, the OPN3 RNA level and overall survival (OS) in relation to its expression level in 33 cancer types were estimated. Based on the analysis above, 347 samples from 5 types of tumours were collected and detected for the protein expression of OPN3 by immunohistochemical assay. Furthermore, the biological role of OPN3 in cancers was evaluated via gene set enrichment analysis (GSEA).

Results

The OPN3 expression level was heterogeneous across cancers, yet a remarkable difference existed between OPN3 expression and patient overall survival among the 7 types of these 33 cancers. Consistently, a high immunohistochemical score of OPN3 was significantly associated with a poor prognosis among patients with 5 types of tumours. Additionally, OPN3 expression was involved in cancer-associated fibroblast infiltration in 5 types of tumours, and promoter hypomethylation of OPN3 was observed in 3 tumour types. Additionally, OPN3 protein phosphorylation sites of Tyr140 and Ser380 were identified via posttranscriptional modification analysis, suggesting the potential function of Tyr140 and Ser380 phosphorylation in tumorigenesis. Furthermore, the enrichment analysis was mainly concentrated in C7orf70, C7orf25 and the “ribosome” pathway by GSEA in 5 types of cancers, indicating that OPN3 might affect tumorigenesis and progression by regulating gene expression and ribosome biogenesis.

Conclusions

High expression of OPN3 was significantly associated with a poor clinical prognosis in five types of cancers. Its molecular function was closely associated with the ribosomal pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09219-7.