Search Results (216)

Atopic dermatitis (AD) is a chronic inflammatory dermatosis driven by skin barrier impairment and immune dysregulation. This study aimed to investigate the anti-inflammatory and barrier-related effects of the ethanol extract of Bidens bipinnata L. fruits (EEBB) in a calcipotriol (MC903)-induced AD-like dermatitis mouse model and lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. In vivo, repeated topical application of EEBB (60, 180, and 600 μg/day) significantly attenuated MC903-induced AD-like clinical symptoms, skin weight, and erythema index. Notably, EEBB significantly improved skin hydration-related parameters, including relative skin hydration readings and the post-application moisture retention profile, and partially restored filaggrin and loricrin expression in lesional skin, whereas dexamethasone showed limited effects on these hydration-related parameters under the present conditions. Histopathologically, EEBB ameliorated epidermal lesions and reduced inflammatory cell infiltration. Mechanistically, EEBB suppressed the levels of pro-inflammatory (TNF-α, IFN-γ) and Th2 (IL-4, IL-5) cytokines in lesional skin. In vitro, EEBB significantly inhibited the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂), and downregulated inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression in RAW 264.7 cells. These effects were associated with inhibited phosphorylation of JNK and p38 MAPK, with no marked effect on ERK phosphorylation under the present conditions. In conclusion, EEBB effectively alleviated AD-like dermatitis, accompanied by improved skin hydration and restoration of barrier-related protein expression, attenuation of local inflammatory responses, and targeted inhibition of the MAPK signaling pathway. Full article

Dandruff (DF) is a prevalent, recurrent inflammatory scalp disorder increasingly recognized as a complex state of functional dysbiosis rather than a simple Malassezia overcolonization. The scalp microbiome is predominantly shaped by Malassezia species (M. restricta and M. globosa), Cutibacterium, and Staphylococcus species. Recent multi-omics evidence indicates that DF pathogenesis is driven by the destabilization of microbial interaction networks and strain-level functional heterogeneity, characterized by the disruption of the C. acnes/S. epidermidis balance and the opportunistic expansion of Staphylococcus aureus. Mechanistically, Malassezia utilizes its lipolytic repertoire to hydrolyze host sebum into irritant free fatty acids and peroxides. Concurrently, oxidative metabolites like squalene peroxide (SQOOH) penetrate the stratum corneum to activate the NF-κB and aryl hydrocarbon receptor (AhR) pathways, triggering a pro-inflammatory cascade that overexpresses keratins (K6/16/17) and downregulates filaggrin. This molecular cascade drives abnormal keratinocyte turnover and lipidomic remodeling, establishing a self-perpetuating “metabolism–inflammation–barrier disruption” pathological cycle. This review systematically elucidates the molecular etiology of DF as an ecological disorder driven by a tripartite imbalance among the microbiome, host physiology, and the environmental niche. We propose that next-generation therapeutic paradigms must transcend traditional antifungal eradication, focusing instead on targeted molecular intervention and microecological restoration to recalibrate overall scalp homeostasis. Full article

The vitamin D receptor (VDR) plays a pivotal role in maintaining epidermal barrier homeostasis and regulating cutaneous inflammatory responses. However, the cosmetic application of vitamin D and its active metabolites is limited by photoinstability, formulation challenges, and regulatory considerations. In this study, we evaluated a synthetic VDR-activating peptide (VDR-Pep) as a potential functional cosmetic ingredient capable of modulating VDR-associated signaling pathways in human keratinocytes. In situ proximity ligation assays (PLAs) demonstrated that VDR-Pep enhanced the heterodimerization of VDR and retinoid X receptor (RXR), indicating activation of canonical VDR signaling. Treatment with VDR-Pep significantly increased the expression of S100A3 and key terminal differentiation markers, including filaggrin, involucrin, and loricrin, in a dose-dependent manner. In addition, VDR-Pep stimulated intracellular calcium mobilization at levels comparable to or exceeding those induced by 1,25-dihydroxyvitamin D₃. Under UVB-induced stress conditions, the peptide attenuated the expression of the pro-inflammatory cytokine interleukin-6 (IL-6) and enhanced NRF2-associated transcriptional engagement, as evidenced by increased interaction between NRF2 and RNA polymerase II. Collectively, these findings suggest that VDR-Pep supports epidermal homeostasis through coordinated modulation of VDR/RXR signaling, calcium-mediated differentiation, barrier-related protein expression, inflammatory responses, and antioxidant-associated pathways. The results indicate that VDR-targeting peptides may represent a promising non-hormonal strategy for cosmetic formulations aimed at reinforcing skin barrier function and improving resilience to environmental stress. Future studies should focus on validating these effects in in vivo human skin models, assessing long-term safety and efficacy, and optimizing formulation stability for practical cosmetic applications. Full article

Food allergy (FA) and eosinophilic esophagitis (EoE) represent two of the most rapidly increasing allergen-driven conditions in pediatric medicine. Both diseases share key immunological features, including Th2 polarization and epithelial barrier dysfunction. Over the past two decades, compelling epidemiological and mechanistic evidence has established EoE as a late-manifesting component of the allergic march—the well-recognized sequential progression of atopic disease in childhood, which typically begins with atopic dermatitis, followed by IgE-mediated food allergy, allergic rhinitis, and asthma. Children with IgE-mediated food allergy carry a substantially elevated risk of developing EoE, and shared genetic susceptibility loci—including CAPN14, TSLP, and filaggrin (FLG)—underscore common pathogenic pathways. We conducted a narrative review of the literature by systematically searching PubMed/MEDLINE, EMBASE, and the Cochrane Library using the terms “eosinophilic esophagitis,” “food allergy,” “atopic march,” “IgE-mediated allergy,” and “pediatric” in combination; articles published from 2000 to March 2026 were considered, with priority given to systematic reviews, meta-analyses, randomized controlled trials, and guideline documents. This narrative review comprehensively examines the epidemiology, pathomechanisms, clinical presentation, diagnostic approach, and therapeutic landscape for pediatric FA and EoE, with particular emphasis on their immunological intersections and the evolving evidence positioning EoE within atopic disease trajectories. We highlight approval of dupilumab for children as young as 1 year with EoE—representing a paradigm shift toward biologic therapy for atopic multimorbidity—and discuss the pipeline of emerging agents including cendakimab, lirentelimab, and anti-IL-5 strategies. Identification of shared pathogenic mechanisms offers promising avenues for unified prevention, early diagnosis, and precision therapeutic approaches for children with multiple atopic diseases. Full article

Maintaining a balanced skin microbiota is essential for preserving epidermal barrier integrity and overall skin health. Dysbiosis, particularly the opportunistic overgrowth of Staphylococcus aureus, is associated with barrier dysfunction and inflammatory dermatoses such as atopic dermatitis, psoriasis, and acne. In dysbiotic states, microbial regulatory mechanisms become disrupted, enabling pathogenic strains to proliferate and release proteases that degrade structural components of the skin barrier, increasing epidermal permeability in a manner analogous to ‘leaky gut’ physiopathology. Microbiota dysbiosis has further been proposed as an emerging hallmark of aging, contributing to chronic low-grade inflammation, impaired tissue repair, and progressive barrier decline. Current strategies predominantly target the microbiota itself, leaving the host tissue response to protease-mediated barrier disruption comparatively underaddressed. To fill this gap, an ex vivo human skin model was developed based on topical application of purified S. aureus serine protease SspA to skin explants, enabling controlled investigation of early host–microbiota interaction events. Barrier function, junctional integrity, inflammatory mediators, and proteostasis were assessed through a panel of complementary biomarkers—Lucifer Yellow permeability, claudin-1, desmoglein-1, filaggrin, IL-31, S100A8/A9, PGE2, and protein carbonylation. SspA induced measurable barrier disruption, junctional protein loss, inflammatory mediator upregulation, and proteostasis impairment without overt tissue damage. A biotic culture filtrate of Bifidobacterium adolescentis partially attenuated SspA-induced protein carbonylation. This model provides the scientific community with a controlled, biologically relevant platform for identifying biomarkers of early barrier impairment and evaluating host-targeted interventions aimed at preventing or counteracting protease-driven barrier damage in dysbiosis-associated skin conditions. A better understanding of the early molecular mechanisms through which microbial virulence factors drive barrier disruption and proteostasis decline may further contribute to broader strategies aimed at preserving skin integrity during aging. Full article

Atopic dermatitis (AD) is a chronic inflammatory skin disease with a complex pathogenesis involving epidermal barrier dysfunction, microbiome dysbiosis, and immune dysregulation. Despite significant advances in therapy, including biologics and targeted treatments, their use may be limited by adverse effects, highlighting the need for safe adjunctive strategies. Polyphenols are naturally occurring bioactive compounds that are abundant in plant-based foods and are known for their anti-inflammatory, antioxidant, and immunomodulatory properties, making them promising candidates for supportive AD management. This review integrates current evidence on the effects of polyphenols on epidermal barrier lipids, microbiome interactions, and key inflammatory pathways, including NF-κB and JAK/STAT signaling. Additionally, the role of polyphenols in modulating dendritic cell and neutrophil activity, and reducing reactive oxygen species (ROS) production and neutrophil extracellular trap (NET) formation, as well as their potential involvement in mitophagy regulation, is discussed. Polyphenols support epidermal barrier integrity by modulating the expression of key structural proteins, including filaggrin, involucrin, and loricrin, leading to a reduction in transepidermal water loss (TEWL). Furthermore, they interact bidirectionally with the gut microbiome, acting as metabolic substrates for beneficial bacteria and promoting the growth of short-chain fatty acid (SCFA)-producing species such as Lactobacillus, Bifidobacterium, and Akkermansia, while simultaneously inhibiting pathogenic strains. These findings highlight the role of polyphenols in maintaining microbiome homeostasis and supporting epidermal barrier integrity. The review encompasses findings from clinical studies, animal models, and mechanistic investigations, while also addressing limitations related to polyphenol bioavailability. Overall, polyphenols may represent a valuable adjunctive approach in AD management; however, further well-designed clinical and mechanistic studies are required to confirm their therapeutic potential. Full article

Background/Objectives: Native to the Indo-Pacific region, edible bird’s nests (EBN; Yan Wo in Chinese) are the solidified saliva of swiftlets (Aerodramus fuciphagus and A. maximus) and have been consumed as a traditional functional food for centuries. However, the bioactive components and underlying mechanisms of EBN remain poorly understood. EBN consists of over 60% protein, much of which is heavily glycosylated, forming complex glycoconjugates that are resistant to enzymatic digestion. This study examines the properties of EBN-derived bioactive peptides and assesses their potential for skin moisturization and anti-inflammation when applied topically. Methods: EBN was double-boiled for an extended period, then digested with gastric enzymes to extract active peptides. Digestion was over 90% efficient, and peptide molecular weights were measured. The enzymatic digest was then fractionated using an activity-guided approach based on assays for skin moisturization and anti-inflammatory properties. Results: A novel bioactive heptapeptide, with the sequence LAGAAHF and designated EBN_P3, was identified and characterized. It attenuated TNF-α-induced inflammatory responses in HaCaT keratinocytes and alleviated dermatitis symptoms in a DNCB-induced C57BL/6 mouse model. Conclusions: EBN-derived peptides with skin moisturizing and anti-inflammatory activities hold significant promise for development into functional ingredients for skincare products. Full article

Scalp microbes are recognized as contributors to hair loss by influencing scalp homeostasis and hair growth. However, the in vitro anti-hair loss activity of microbial culture media derived from healthy scalps remains unclear. In this study, resident microbes from 20 Korean participants with healthy scalps and hair were isolated, and Staphylococcus capitis was used to produce S. capitis ferment filtrate (SCFF). SCFF anti-hair loss activity was evaluated in human follicle dermal papilla cells (HFDPCs) and human adult low-Calcium High-Temperature (HaCaT) keratinocytes via proliferation assays, qPCR, immunocytochemistry, and SA-β-gal staining at 250–1000 μg/mL. SCFF increased cell density after 48 h in a concentration-dependent manner. In HFDPCs, SCFF controlled growth (KGF, IGF-1, and HGF) and androgen (AR and TGF-β2) factors, regulating key mRNAs for hair growth. SCFF mitigated scalp and hair aging by promoting sirtuins 1 and 7 and collagen type 13, while suppressing p21 and X-Gal staining. In HaCaT cells, SCFF exhibited a scalp barrier-strengthening effect by significantly increasing filaggrin and involucrin levels. It suppressed reactive oxidative stress and exhibited DPPH and ABTS radical scavenging activity. These results suggest that SCFF may modulate key pathways associated with hair loss by promoting scalp and hair anti-aging, barrier strengthening, enhancing antioxidant activity, and supporting hair growth. Full article

Atopic dermatitis (AD) is a chronic inflammatory dermatosis driven by skin barrier dysfunction, immune dysregulation, and gut–skin axis imbalance. While probiotics show promise, the therapeutic potential and mechanisms of topical postbiotics in modulating the gut–skin axis remain understudied. Here, we investigated the efficacy of Schleiferilactobacillus harbinensis JNDM-derived cell-free supernatant (CFS) and lysate (ShL) in a DNFB-induced AD mouse model. Topical application of both CFS and ShL significantly attenuated AD-like symptoms, reduced epidermal thickening, and restored the expression of the barrier protein filaggrin. Immunologically, treatment suppressed the Th2-dominant inflammatory cascade (IL-4, IL-5, IL-13, IL-33, TSLP) and reduced serum IgE and IFN-γ levels. Notably, ShL exhibited superior systemic efficacy, significantly inhibiting mast cell infiltration and reducing the spleen index. 16S rRNA sequencing revealed that topical intervention remotely remodeled the gut microbiota, specifically reversing the depletion of the beneficial genus Alistipes and suppressing the compensatory increase in Odoribacter. This microbial restructuring was accompanied by distinct metabolic changes: ShL treatment resulted in an approximately 4-fold elevation in fecal butyrate concentrations compared with the model group. Correlation analysis further validated a strong positive axis linking Alistipes abundance and butyrate levels to skin barrier integrity. Collectively, our findings demonstrate that S. harbinensis postbiotics—particularly the lysate—ameliorate AD through a dual mechanism of local barrier repair and systemic metabolic modulation via the gut–skin axis, presenting a promising non-steroidal therapeutic strategy. Full article

Ultraviolet (UV) irradiation induces complex skin damage, including hyperpigmentation, oxidative stress, and alterations in proteins related to keratinocyte differentiation and epidermal barrier-associated status. This study investigated the multifunctional protective effects of Padina arborescens ethanolic extract (PAEE) against skin damage in melanocytes, keratinocytes, and zebrafish. In alpha-melanocyte-stimulating hormone (α-MSH)-stimulated B16F10 cells, PAEE effectively suppressed the protein kinase A (PKA)/cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB) signaling pathway, which was associated with reduced expression of microphthalmia-associated transcription factor (MITF) and tyrosinase, leading to decreased melanin synthesis. PAEE also exhibited photoprotective properties by reducing reactive oxygen species (ROS), inhibiting interleukin-1 beta (IL-1β), and attenuating matrix metalloproteinase-1 (MMP-1) upregulation associated with UVB (ultraviolet B)-induced photodamage in HaCaT keratinocytes. Notably, PAEE restored the UVB-reduced expression of filaggrin and involucrin, representative markers of keratinocyte differentiation and epidermal barrier-associated status, in HaCaT keratinocytes. In zebrafish embryos, PAEE suppressed α-MSH-induced melanin accumulation and UVB-induced ROS generation at non-toxic concentrations. Taken together, these results suggest that PAEE exerts anti-melanogenic and photoprotective effects in cellular and zebrasfish models and may serve as a promising marine-derived ingredient for cosmeceutical applications targeting UVB-related skin damage. Full article

Background/Objectives: Thymic stromal lymphopoietin (TSLP) is central to the pathogenesis of atopic dermatitis (AD) and a promising therapeutic target. However, developing small-molecule TSLP inhibitors is challenging due to the difficulty in disrupting the TSLP-TSLPR interface. This study aimed to explore naturally sourced blockers of the TSLP-TSLPR interaction and identify novel candidate compounds for AD treatment. Methods: HuT78 cells were stimulated with PMA, ionomycin, and TSLP to establish an AD model. Inflammatory cytokines were measured by qRT-PCR and ELISA. JAK/STAT signaling was analyzed by Western blot. In female BALB/c mice, DNCB-induced AD-like skin lesions were topically treated with test compounds, followed by histopathological and immunohistochemical assessment. Results: Eight compounds were screened, and their key structural features were elucidated via structure–activity relationship (SAR) analysis. Among them, kaempferol-7-O-glucoside (K-7-G) emerged as the most potent candidate. It interfered with the TSLP-TSLPR interaction, selectively inhibited TSLP-mediated JAK2/STAT5 phosphorylation, and significantly downregulated IL-4 (p < 0.0001) and IL-13 (p < 0.001) levels. Topical application of 1% K-7-G significantly alleviated AD-like symptoms in a mouse model, decreasing dorsal skin thickness, dermatitis score, and scratching frequency while restoring the expression of filaggrin, loricrin, and occludin (p < 0.0001). Meanwhile, it significantly reduced key inflammatory mediators in a concentration-dependent manner, including TSLP, IL-4, IL-13, TNF-α, IFN-γ, and IgE. Conclusions: This study demonstrates that K-7-G is a novel natural TSLP inhibitor capable of blocking the TSLP-TSLPR signaling pathway and effectively improving AD symptoms. Further research may explore its therapeutic potential in other inflammatory diseases. Full article

This study evaluated the anti-inflammation and anti-photoaging effects of Camellia sinensis seed flavonoids (CSF) against UVB and UVA irradiation and elucidated the underlying mechanisms. Using UVB-irradiated human keratinocytes and UVA-irradiated human dermal fibroblasts, we found that CSF significantly reduced intracellular ROS and suppressed the secretion of inflammatory factors (PGE-2, TNF-α, IL-6, IL-8) by inhibiting the p38/JNK and NF-κB pathways, along with iNOS and COX-2 expression. In keratinocytes, CSF also downregulated Caspase-3 and upregulated barrier proteins filaggrin and Claudin-1. In fibroblasts, CSF counteracted UVA damage by upregulating collagen IV and XVII at the dermo-epidermal junction and enhancing the production of collagen I, III, and hyaluronic acid in the dermis, mediated via AP-1 inhibition and TGF-β/Smad pathway modulation. These results demonstrate that CSF coordinated anti-inflammatory, barrier-repair, and anti-photoaging actions, highlighting its potential as a promising skincare ingredient. Full article

Precise control of keratinocyte proliferation and differentiation is critical for oral epithelial regeneration, yet the mechanobiological cues guiding these processes remain incompletely defined. Here, we systematically evaluated how electrospun polycaprolactone (PCL) scaffolds with defined fiber orientations (aligned vs. random) and diameters (600–800 nm, 1.2–1.7 µm, 2.0–2.5 µm) direct gingival keratinocyte fate. Using immortalized human gingival keratinocytes, we assessed cell and nuclear morphology, proliferation dynamics, differentiation marker expression, and the effects of basal keratin (KRT5/KRT14) knockdown. Quantitative morphological analysis revealed scaffold-dependent changes in cell shape: aligned medium-diameter fibers (with fiber diameters of 1.2–1.7 µm) induced pronounced cell and nuclear elongation, whereas random fibers (600–800 nm) promoted larger, more rounded cell and nuclear shapes. Time-resolved EdU assays indicated that aligned scaffolds supported sustained proliferation, whereas random scaffolds elicited a transient proliferative burst followed by a decline. Gene expression analysis (ddPCR) demonstrated that random scaffolds (especially 600–800 nm fibers) upregulated basal keratins (KRT5, KRT14) and early differentiation markers (KRT1, KRT10, KRT4, KRT13) relative to aligned scaffolds. At the protein level, differentiation markers involucrin (IVL) and filaggrin (FLG) were likewise elevated on random scaffolds, corroborating the mRNA findings. Functional KRT5/KRT14 knockdown experiments revealed scaffold-specific dependencies: cells on random scaffolds required these keratins for viability, whereas aligned cultures remained viable upon KRT5/14 loss. Furthermore, KRT5/14 depletion differentially altered downstream differentiation markers (IVL, KRT1) and mechanotransduction markers (LMNB1, YAP1) in a scaffold-dependent manner. Collectively, these findings establish fiber orientation and diameter as key design parameters for controlling keratinocyte fate. As a translational concept, layered scaffolds combining aligned and random fibers may enable spatially controlled proliferation and differentiation in engineered oral epithelia. Full article

Skin photoaging, marked by structural and functional changes, is mainly caused by long-term ultraviolet (UV) exposure. This study sought to create hydroxytyrosol (HT)-loaded soluble microneedles (HT MNs) and thoroughly assess their anti-photoaging effects and underlying mechanisms in vitro and in vivo. The optimized HT MNs, featuring tips with 10% HT + 5% hyaluronic acid (HA) and a backing layer of 10% polyvinyl pyrrolidone (PVP), demonstrated robust mechanical strength (withstanding an axial force of 10 N without fracture), adequate penetration depth (>200 μm), and efficient skin self-recovery post-removal. In vitro, HT MNs notably boosted cell viability, reduced reactive oxygen species (ROS) levels, and suppressed senescence-associated β-galactosidase (A-β-Gal) expression in UVA-exposed human skin fibroblasts (HSF). In vivo, in a UVA + UVB-irradiated mouse model, HT MNs significantly enhanced skin hydration and elasticity, increased collagen density (confirmed by Masson staining), decreased malondialdehyde (MDA) content, and elevated the activities of glutathione (GSH), catalase (CAT), and glutathione peroxidase (GSH-Px). Western blot analysis further revealed that HT MNs upregulated the expression of collagen type I alpha 1 (COL1A1), elastin (ELN), hyaluronan synthase 2 (HAS2), and filaggrin (FLG), while downregulating matrix metalloproteinase 1. Overall, these findings suggest that HT MNs effectively mitigate UV-induced photoaging through antioxidant, anti-senescence, and extracellular matrix (ECM)-regulating mechanisms, underscoring their potential as a novel transdermal anti-photoaging therapy. Full article

Tremella mesenterica, commonly known as the yellow brain or golden jelly fungus, has been traditionally used for its medicinal properties. In this study, we elucidated the structural characteristics of T. mesenterica polysaccharide (TMP) and evaluated its potential moisturizing mechanism in vitro, comparing it to Tremella fuciformis polysaccharide (TFP) and hyaluronic acid (HA). TMP was isolated through enzyme assisted extraction and it has a molecular weight (MW) of approximately 143 kDa. We investigated the composition of mannose, xylose, glucuronic acid, and glucose as a ratio of 59.8 ± 0.3, 24.0 ± 1.2, 11.0 ± 0.8, 5.2 ± 0.0, respectively. Through methylation and GC-MS analysis, we discovered TMP was composed of a main chain of β-(1→3)-linked mannopyranoside, substituted with various side chains such as xylopyranoside, glucuronopyranoside, glucopyranoside at the C-2 or C-4 positions of the backbone. TMP upregulated the expression of key moisturizing-related factors compared to TFP and HA, such as aquaporin-3 (AQP3) with 55% and 57% at 25 and 50 μg/mL and hyaluronic acid synthase-2 (HAS2) with 22% at 25 μg/mL, as confirmed through qRT-PCR analysis. Additionally, TMP significantly enhanced the expression of filaggrin (FLG), a critical protein involved in skin barrier function, with 22% at 25 μg/mL. Immunocytochemistry (ICC) analysis further revealed that TMP achieved the highest improvement in hyaluronic acid synthase-3 (HAS3) protein levels by 475% at 50 μg/mL. While further in vivo studies are required to substantiate its functional moisturizing efficacy, these findings suggest that TMP serves as a promising moisturizing agent. The structural and functional properties of TMP provide a potential foundation for its application in diverse industries, including cosmetics, food, biopolymers, and pharmaceuticals. Full article