PAL-12, a new anti-aging hexa-peptoid, inhibits UVB-induced photoaging in human dermal fibroblasts and 3D reconstructed human full skin model, Keraskin-FT™

Withania somnifera root extract inhibits MGO-induced skin fibroblast cells dysfunction via ECM-integrin interaction

ETHNOPHARMACOLOGICAL RELEVANCE

Withania somnifera (L.) Dunal, known as Ashwagandha, has long been used in traditional medicine in Ayurveda, India, a representative adaptogen. The main active constituents of W. somnifera are withanolides, and the root is often used as a medicine with a wide range of pharmacological activities, which can be used to treat insomnia, neurasthenia, diabetes mellitus and skin cancer.

AIM OF THE STUDY

Whole-component qualitative and quantitative analyses were performed on W. somnifera. We explored the ameliorative effect of the adaptogen representative plant W. somnifera on the senescence events of MGO-injured fibroblasts and its action mechanism and verified the hypotheses that WS can inhibit the accumulation of AGEs and regulate the dynamic balance among the components of the ECM by modulating the expression of integrin β1 receptor; as a result, WS maintains cellular behavioural and biological functions in a normal range and retards the aging of skin from the cellular level.

MATERIALS AND METHODS

In this study, the components of WS were first qualitatively and quantitatively analysed by HPLC fingerprinting and LC-MS detection. Second, a model of MGO-induced injury of CML-overexpressing fibroblasts was established. ELISA was used to detect CML expression and the synthesis of key extracellular matrix ECM protein components COL1, FN1, LM5 and TNC synthesis; CCK-8 was used to detect cell viability; EDU was used to detect cell proliferation capacity; fluorescence was used to detect cell adhesion capacity; and migration assay were used to detect cell migration capacity; qRT-PCR was used to detect the regulatory pathway TGF-β1 and MMP-2, MMP-9 in ECMs; immunofluorescence was used to detect the expression of ITGB1; and WB was used to detect the expression of COL1, FN1, LM5, Tnc, TGF-β1, MMP-2, MMP-9 and ITGB1.

RESULTS

In total, 27 active ingredients were analysed from WS, which mainly consisted of withanolide components, such as withaferin A and withanolide A. Based on the model of MGO-induced fibroblast senescence injury, WS significantly inhibited CML synthesis. By up-regulating the expression of integrin β1, it upregulated the expression of the TGF-β1 gene, which is closely related to the generation of ECMs, downregulated the expression of the MMP-2 and MMP-9 genes, which are closely related to the degradation of ECMs, maintained the dynamic balance of the four types of ECMs, and improved cell viability as well as proliferation, migration and adhesion abilities.

CONCLUSIONS

WS can prevent cellular behavioural dysfunction and delay skin ageing by reducing the accumulation of CML, upregulating the expression of the ITGB1 receptor, maintaining the normal function of ECM-integrin receptor interaction and preventing an imbalance between the production and degradation of protein components of ECMs. The findings reported in this study suggest that WS as a CML inhibitor can modulate ECM-integrin homeostasis and has great potential in the field of aging retardation.

Electric currents of 448 kHz upregulate anti-senescence pathways in human dermal fibroblasts

BACKGROUND

Currently, finding new therapeutic strategies that reduce skin aging is a challenge for dermatologists and aesthetic doctors. In recent years, physical therapies have been included in the options for antiaging treatments; however, the biological bases of such treatments have scarcely been studied. One of these physical therapies is capacitive-resistive electric transfer (CRET) therapy. Previous studies have shown that subthermal treatment with CRET promotes the proliferation and migration of various cell types involved in skin regeneration, such as human ADSC (stem cells), fibroblasts, or keratinocytes.

OBJECTIVE

This study investigates the effects of in vitro treatment with CRET-Std (standard, non-modulated signal) or CRET-Mod (modulated signal) on cell proliferation and migration, markers of aging, and extracellular matrix production.

METHODS

Three types of human dermal fibroblasts were used: neonatal fibroblasts (HFn), replicative senescent fibroblasts (HFs), and adult fibroblasts (HFa). The effects of electric stimulation on cell proliferation and migration were studied through XTT and wound closure assays, respectively. The expression of the aging marker β-galactosidase was assessed using a colorimetric assay, whereas immunoblot, immunofluorescence, and ELISAs were carried out to analyze the expression levels of migration, aging, and extracellular matrix proteins.

RESULTS

The treatment with CRET-Std increased HFn and HFa proliferation, as well as migration in the three types of fibroblasts studied compared to those of the controls. Conversely, CRET-Mod did not modify either of these two processes with respect to the controls. Additionally, CRET-Std also reduced the cellular senescence markers β-gal, vimentin, p53, and p21 in all three types of human skin fibroblasts. In addition, the application of CRET-Std also induced fibronectin production in HFn and was able to stimulate ECM neocollagenesis.

CONCLUSION

CRET treatment improves a number of functions related to migration and proliferation, and it reduces age-related cellular changes in human dermal fibroblasts. Therefore, the use of this CRET therapy to reduce the signs of dermal aging and to promote tissue regeneration could be of interest.

Layer-by-Layer Analysis of In Vitro Skin Models

In vitro human skin models are evolving into versatile platforms for the study of skin biology and disorders. These models have many potential applications in the fields of drug testing and safety assessment, as well as cosmetic and new treatment development. The development of in vitro skin models that accurately mimic native human skin can reduce reliance on animal models and also allow for more precise, clinically relevant testing. Recent advances in biofabrication techniques and biomaterials have led to the creation of increasingly complex, multilayered skin models that incorporate important functional components of skin, such as the skin barrier, mechanical properties, pigmentation, vasculature, hair follicles, glands, and subcutaneous layer. This improved ability to recapitulate the functional aspects of native skin enhances the ability to model the behavior and response of native human skin, as the complex interplay of cell-to-cell and cell-to-material interactions are incorporated. In this review, we summarize the recent developments in in vitro skin models, with a focus on their applications, limitations, and future directions.

Analysis of Skin Regeneration and Barrier-Improvement Efficacy of Polydeoxyribonucleotide Isolated from Panax Ginseng (C.A. Mey.) Adventitious Root

Polydeoxyribonucleotide (PDRN) has the ability to regenerate skin cells and improve the skin barrier and wound healing. This study investigated the possibility of replacing animal-derived PDRN with plant-derived PDRN. To test this, the adventitious roots of Korean ginseng (Panax ginseng C.A. Meyer), which is commonly used to treat various diseases, were suspension-cultivated through tissue culture; subsequently, PDRN was purified using microfluidization, an ultra-high-pressure physical grinding method. The results showed that purified Panax PDRN was effective in healing skin wounds and enhancing the skin barrier. Panax PDRN promoted the proliferation of keratinocytes and fibroblasts by increasing the expression of fibronectin, filaggrin, Ki-67, Bcl-2, inhibin beta A, and Cyclin D1. It also acted as an agonist of the adenosine A2A receptor and induced the phosphorylation of focal adhesion kinase, adenosine triphosphate-dependent tyrosine kinase, and mitogen-activated protein kinase. This activated signal transduction, thereby regenerating skin cells and strengthening the barrier. These results were not only observed in skin cells but also in an artificial skin model (KeraSkinTM). The use of plant-derived PDRN instead of animal-derived PDRN can promote animal welfare and environmental sustainability. Furthermore, Panax PDRN can potentially be a new plant-derived PDRN (PhytoPDRN) that may be utilized in the treatment of various skin diseases.

CO2 lattice laser reverses skin aging caused by UVB

The carbon dioxide (CO₂) lattice laser has been successfully used to treat facial skin photoaging induced by UV light. In this study, we analyzed the effect of CO₂ lattice laser irradiation on skin photoaging, and investigated the underlying mechanisms. Our results demonstrate that the laser promoted collagen synthesis and proliferation of primary human skin fibroblasts, inhibited cell senescence, and induced expression of superoxide dismutase (SOD) and the signaling protein SMAD3. In addition, this laser reversed cell cycle arrest and fibroblast apoptosis induced by UVB irradiation, and restored fibroblast proliferation inhibited by SMAD3 silencing. Using a rat model of photoaging, our results show that the laser increased collagen expression and dermal thickness, demonstrating that the CO₂ lattice laser has a profound therapeutic effect on photoaged skin. Together, our in vitro and in vivo data show that the CO₂ lattice laser can reverse the skin aging caused by UVB, and indicate that this effect is mediated through SMAD3.

Peptide science: A "rule model" for new generations of peptidomimetics

Peptides have been heavily investigated for their biocompatible and bioactive properties. Though a wide array of functionalities can be introduced by varying the amino acid sequence or by structural constraints, properties such as proteolytic stability, catalytic activity, and phase behavior in solution are difficult or impossible to impart upon naturally occurring α-L-peptides. To this end, sequence-controlled peptidomimetics exhibit new folds, morphologies, and chemical modifications that create new structures and functions. The study of these new classes of polymers, especially α-peptoids, has been highly influenced by the analysis, computational, and design techniques developed for peptides. This review examines techniques to determine primary, secondary, and tertiary structure of peptides, and how they have been adapted to investigate peptoid structure. Computational models developed for peptides have been modified to predict the morphologies of peptoids and have increased in accuracy in recent years. The combination of in vitro and in silico techniques have led to secondary and tertiary structure design principles that mirror those for peptides. We then examine several important developments in peptoid applications inspired by peptides such as pharmaceuticals, catalysis, and protein-binding. A brief survey of alternative backbone structures and research investigating these peptidomimetics shows how the advancement of peptide and peptoid science has influenced the growth of numerous fields of study. As peptide, peptoid, and other peptidomimetic studies continue to advance, we will expect to see higher throughput structural analyses, greater computational accuracy and functionality, and wider application space that can improve human health, solve environmental challenges, and meet industrial needs. STATEMENT OF SIGNIFICANCE: Many historical, chemical, and functional relations draw a thread connecting peptides to their recent cognates, the "peptidomimetics". This review presents a comprehensive survey of this field by highlighting the width and relevance of these familial connections. In the first section, we examine the experimental and computational techniques originally developed for peptides and their morphing into a broader analytical and predictive toolbox. The second section presents an excursus of the structures and properties of prominent peptidomimetics, and how the expansion of the chemical and structural diversity has returned new exciting properties. The third section presents an overview of technological applications and new families of peptidomimetics. As the field grows, new compounds emerge with clear potential in medicine and advanced manufacturing.

Solid-Phase Insertion of N-mercaptoalkylglycine Residues into Peptides

N-mercaptoalkylglycine residues were inserted into peptides by reacting N-free amino groups of peptides, which were initially synthesized on 2-chlorotrityl resin (Cltr) using the Fmoc/^tBu method, with bromoacetic acid and subsequent nucleophilic replacement of the bromide by reacting with S-4-methoxytrityl- (Mmt)/S-trityl- (Trt) protected aminothiols. The synthesized thiols containing peptide–peptoid hybrids were cleaved from the resin, either protected by treatment with dichloromethane (DCM)/trifluoroethanol (TFE)/acetic acid (AcOH) (7:2:1), or deprotected (fully or partially) by treatment with trifluoroacetic acid (TFA) solution using triethylsilane (TES) as a scavenger.

Lysates of a Probiotic, Lactobacillus rhamnosus, Can Improve Skin Barrier Function in a Reconstructed Human Epidermis Model

The main function of the skin is to protect the body from the external environment. The barrier function of the skin is mainly provided by the stratum corneum, which consists of corneocytes bound with the corneodesmosomes and lamellar lipids. Skin barrier proteins like loricrin and filaggrin also contribute to the skin barrier function. In various skin diseases, skin barrier dysfunction is a common symptom, and skin irritants like detergents or surfactants could also perturb skin barrier function. Many efforts have been made to develop strategies to improve skin barrier function. Here, we investigated whether the microfluidized lysates of Lactobacillus rhamnosus (LR), one of the most widely used probiotic species for various health benefits, may improve the skin barrier function in a reconstructed human epidermis, Keraskin™. Application of LR lysate on Keraskin™ increased the expression of tight junction proteins; claudin 1 and occludin as determined by immunofluorescence analysis, and skin barrier proteins; loricrin and filaggrin as determined by immunohistochemistry and immunofluorescence analysis and qPCR. Also, the cytotoxicity of a skin irritant, sodium lauryl sulfate (SLS), was alleviated by the pretreatment of LR lysate. The skin barrier protective effects of LR lysate could be further demonstrated by the attenuation of SLS-enhanced dye-penetration. LR lysate also attenuated the destruction of desmosomes after SLS treatment. Collectively, we demonstrated that LR lysate has protective effects on the skin barrier, which could expand the utility of probiotics to skin-moisturization ingredients.

Fasiglifam (TAK-875), a G Protein-Coupled Receptor 40 (GPR40) Agonist, May Induce Hepatotoxicity through Reactive Oxygen Species Generation in a GPR40-Dependent Manner

Fasiglifam (TAK-875) a G-protein coupled receptor 40 (GPR40) agonist, significantly improves hyperglycemia without hypoglycemia and weight gain, the major side effects of conventional anti-diabetics. Unfortunately, during multi-center Phase 3 clinical trials, unexpected liver toxicity resulted in premature termination of its development. Here, we investigated whether TAK-875 directly inflicts toxicity on hepatocytes and explored its underlying mechanism of toxicity. TAK-875 decreased viability of 2D and 3D cultures of HepG2, a human hepatocarcinoma cell line, in concentration- (>50 μM) and time-dependent manners, both of which corresponded with ROS generation. An antioxidant, N-acetylcysteine, attenuated TAK-875-mediated hepatotoxicity, which confirmed the role of ROS generation. Of note, knockdown of GPR40 using siRNA abolished the hepatotoxicity of TAK-875 and attenuated ROS generation. In contrast, TAK-875 induced no cytotoxicity in fibroblasts up to 500 μM. Supporting the hepatotoxic potential of TAK-875, exposure to TAK-875 resulted in increased mortality of zebrafish larvae at 25 μM. Histopathological examination of zebrafish exposed to TAK-875 revealed severe hepatotoxicity as manifested by degenerated hypertrophic hepatocytes with cytoplasmic vacuolation and acentric nuclei, confirming that TAK-875 may induce direct hepatotoxicity and that ROS generation may be involved in a GPR40-dependent manner.

Human skin explants an in vitro approach for assessing UVB induced damage

Lifestyle changes involving frequent outdoor activities are contributing to higher exposure to harmful ultraviolet light (UVB). The acute effects of UVB irradiation on human skin was evaluated in this study using freshly excised human skin from elective surgery subjected to UVB doses (0-3.76 J/cm²). The assessment of UVB induced cellular and skin damages was undertaken at two time points immediately and 24 h post exposure using in vitro, and immunohistochemical staining techniques. The results indicated no significant loss of skin integrity or significant acute mitochondrial cellular damages in UVB exposed skin sections as measured by the MTS cytotoxicity assay. The other key markers of damage showed significant extracellular LDH membrane leakages and upregulation of inflammatory cytokines such as IL-1β. Skin integrity analysis was also undertaken using H&E, HLADR, and anti-cytokeratin antibodies. The results showed significant epidermal changes, basal cell activation and Langerhans cells depletion. The research proved the usefulness of freshly excised human skin explant model in measuring UVB damage. Furthermore, freshly excised human skin maintains the natural layering and therefore does not pose the same challenges faced by commercially available reconstructed skin in terms of higher costs and accurate mimicking of all the complex interactions observed in human skin.