Cell differentiation in the embryonic periderm and in scaffolding epithelia of skin appendages.

Terminal differentiation of epithelial cells is critical for the barrier function of the skin, the growth of skin appendages, such as hair and nails, and the development of the skin of amniotes. Here, we present the hypothesis that the differentiation of cells in embryonic periderm shares characteristic features with the differentiation of epithelial cells that support the morphogenesis of cornified skin appendages during postnatal life. The periderm prevents aberrant fusion of adjacent epithelial sites during early skin development. It is shed off when keratinocytes of the epidermis form the cornified layer, the stratum corneum. A similar role is played by epithelia that ensheath cornifying skin appendages until they disintegrate to allow the separation of the mature part of the skin appendage from the adjacent tissue. These epithelia, exemplified by the inner root sheath of hair follicles and the epithelia close to the free edge of nails or claws, are referred to as scaffolding epithelia. The periderm and scaffolding epithelia are similar with regard to their transient functions in separating tissues and the conserved expression of trichohyalin and trichohyalin-like genes in mammals and birds. Thus, we propose that parts of the peridermal differentiation program were coopted to a new postnatal function during the evolution of cornified skin appendages in amniotes.

LncRNA lnc-SPRR2G-2 contributes to keratinocyte hyperproliferation and inflammation in psoriasis by activating the STAT3 pathway and downregulating KHSRP.

Psoriasis is a chronic inflammatory disease characterized by increased keratinocyte proliferation and local inflammation. Long noncoding RNAs (lncRNAs) play important regulatory roles in many immune-mediated diseases, including psoriasis. In this study, we aimed to investigate the role and mechanism of lnc-SPRR2G-2 (SPRR2G) in M5-treated psoriatic keratinocytes. Fluorescence in situ hybridization and quantitative real-time polymerase chain reaction (qRT-PCR) showed that lnc-SPRR2G-2 was significantly upregulated in psoriasis tissues and psoriatic keratinocytes. In psoriatic keratinocytes, functional and molecular experiment analyses demonstrated that SPRR2G regulated proliferation, cell cycle and apoptosis, and induced the expression of S100 calcium binding protein A7 (S100A7), interleukin (IL)-1ß, IL-8 and C-X-C motif chemokine ligand 10 (CXCL10). The function of SPRR2G in psoriasis is related to the STAT3 signaling pathway and can be inhibited by a STAT3 inhibitor. Moreover, KH-type splicing regulatory protein (KHSRP) was proved to be regulated by lnc-SPRR2G-2 and to control the mRNA decay of psoriasis-related cytokines (p < 0.05). In summary, we reported the functions of lnc-SPRR2G-2 and KHSRP in psoriasis. Our findings provide new insights for the further exploration of the pathogenesis and treatment of psoriasis.

Complement C3 deficient mice show more severe imiquimod-induced psoriasiform dermatitis than wild-type mice regardless of the commensal microbiota.

The complement active product, C3a, and the receptor C3aR comprise an axis that exerts various biological functions, such as protection against infection. C3a is highly expressed in the inflamed skin and blood from patients with psoriasiform dermatitis. However, the role of the C3a/C3aR axis in psoriasiform dermatitis remains unclear because conflicting results using C3-/- mice have been published. In this study, to elucidate the contribution of commensal microbiota in C3-/- and wild-type (WT) mice were subjected to imiquimod-induced psoriasiform dermatitis under different housing conditions. C3-/- mice showed increased epidermal thickness and keratinocyte proliferation markers in the inflamed ear compared to WT mice upon treatment with IMQ. These inflamed phenotypes were observed in both cohoused and separately housed conditions, and antibiotic treatment did not abolish the aggravation of IMQ-induced psoriasiform dermatitis in C3-/- mice. These results suggested that the difference of commensal microbiota is not important for the C3-involved psoriasiform dermatitis. Keratinocyte hyperproliferation is a major feature of the inflamed skin in patients with psoriasiform dermatitis. In vitro experiments showed that C3a and C3aR agonists inhibited keratinocyte proliferation, which was abolished by introduction of a C3aR antagonist. Collectively, these results suggest that the C3a/C3aR axis plays a critical role in psoriasiform dermatitis development by inhibiting keratinocyte proliferation, regardless of the regulation of the commensal microbiota.

Preclinical techniques for drug discovery in psoriasis.

Psoriasis is a chronic, inflammatory, papulosquamous, noncontagious disease characterized by scaly, demarcated erythematous plaque, affecting skin, nails, and scalp. The IL-23/Th17 axis is the main operator in the development of psoriasis. Psoriasis is affecting worldwide, and new treatment options are urgently needed. Various local and systemic treatments are available for psoriasis but they only provide symptomatic relief because of numerous unknown mechanisms. Clinical trials demand overwhelming resources; therefore, drug development predominantly depends on the in-vivo, in-vitro, and ex-vivo techniques. Immediate attention is required to develop experimental techniques that completely imitate human psoriasis to assist drug development. This review portrays the various in-vivo, in-vitro, and ex-vivo techniques used in psoriasis research. It describes these techniques' characteristics, pathological presentations, and mechanisms. The experimental techniques of psoriasis provide significant information on disease progression mechanisms and possible therapeutic targets. However, until now, it has been challenging to invent a timely, affordable model that precisely imitates a human disease. Only the xenotransplantation model is reckoned as the closer, that mimics the complete genetic, and immunopathogenic event. Imiquimod-induced psoriasis and HaCat cell lines are popular among researchers because of their convenience, ease of use, and cost-effectiveness. There need to further improve the experimental techniques to best serve the disease imitation and meet the research goal.

Patient demographic characteristics and risk factors associated with sun protection behaviours in specialist melanoma clinics.

OBJECTIVE: We investigated the association between sun protection behaviours and demographic and melanoma risk characteristics of patients attending Australian melanoma specialist clinics. This may assist in targeting and tailoring melanoma prevention patient education for people at high-risk and specific population subgroups. METHODS: A cross-sectional analysis of questionnaire data collected from participants attending the dermatology clinics at two major melanoma centres in Sydney, Australia between February 2021 and September 2023. The primary outcome was Sun Protection Habits (SPH) index (a summary score measured as habitual past month use of sunscreen, hats, sunglasses, a shirt with sleeves that covers the shoulders, limiting midday sun exposure and seeking shade, using a Likert scale). The primary analysis considered the SPH index and its component items scored as continuous. RESULTS: Data from 883 people were analysed. Factors associated with less frequent sun protection behaviours overall included male gender, no personal history of melanoma, lower perceived risk, lower calculated 10-year risk of developing melanoma, and no private health insurance. People aged >61 years reported lower use of sunscreen but higher use of hats and sleeved-shirts compared with people in the younger age group. There was no difference in overall sun protection behaviours according to family history of melanoma, country of birth or by lifetime melanoma risk among people without a personal history of melanoma. CONCLUSIONS: These findings highlight the potential for targeting high-risk individuals with less frequent use of sun protection for patient education, public health messaging and ultimately improving sun protection behaviours.

Histological and molecular restoration of type VII collagen in Recessive dystrophic epidermolysis bullosa mouse skin by topical injection of keratinocyte-like cells differentiated from human adipose-derived mesenchymal stromal cells.

BACKGROUND: Recessive dystrophic epidermolysis bullosa (RDEB) is a severe skin fragility disorder caused by mutations in the COL7A1 gene, which encodes type VII collagen (COL7), the main constituent of anchoring fibrils for attaching the epidermis to the dermis. Persistent skin erosions frequently result in intractable ulcers in RDEB patients. Adipose-derived mesenchymal stromal cells (AD-MSCs) are easily harvested in large quantities and have low immunogenicity. Therefore, they are suitable for clinical use, including applications involving allogeneic cell transplantation. Keratinocyte-like cells transdifferentiated from AD-MSCs (KC-AD-MSCs) express more COL7 than undifferentiated AD-MSCs and facilitate skin wound healing with less contracture. Therefore, these cells can be used for skin ulcer treatment in RDEB patients. OBJECTIVE: We investigated whether KC-AD-MSCs transplantation ameliorated the RDEB phenotype severity in the grafted skin of a RDEB mouse model (col7a1-null) on the back of the immunodeficient mouse. METHODS: KC-AD-MSCs were intradermally injected into the region surrounding the skin grafts, and this procedure was repeated after 7 days. After a further 7-day interval, the skin grafts were harvested. RESULTS: Neodeposition of COL7 and generation of anchoring fibrils at the dermal-epidermal junction were observed, although experiments were based on qualitative. CONCLUSION: KC-AD-MSCs may correct the COL7 insufficiency, repair defective/reduced anchoring fibrils, and improve skin integrity in RDEB patients.

Polymeric scaffold integrated with nanovesicle-entrapped curcuminoids for enhanced therapeutic efficacy.

Aim: Polymeric scaffolds were developed fortified with nanovesicle-encapsulated individual curcumin (CUR) and tetrahydrocurcumin (THC) for improved therapeutic efficacy due to their low stability and efficacy in native form. Method: Nanovesicle-encapsulated individual CUR and THC were fabricated using thin-film hydration techniques and characterized. Results & conclusion: CUR/THC in native and vesicle-encapsulated form demonstrated diminished LPS-instigate nitric oxide (NO) levels in macrophage cells in a concentration-dependent demeanor. However, vesicle-encapsulated CUR/THC inhibited NO production at lower concentrations, compared with the native CUR/THC form. Furthermore, the scaffold fortified with vesicle-encapsulated CUR/THC demonstrated improved physical properties with excellent antioxidant, biocompatibility, and human keratinocyte cell proliferation ability. The results recommended that nanovesicle-encapsulated THC can be retained as a potential substitute for CUR with improved therapeutic efficacy.

[Box: see text].

Regenerative medicine in the treatment of specific dermatologic disorders: a systematic review of randomized controlled clinical trials.

AIMS AND OBJECTIVES: The aim of this study is to systematically review randomized controlled clinical trials (RCTs) studying various types of regenerative medicine methods (such as platelet-rich plasma, stromal vascular fraction, cell therapy, conditioned media, etc.) in treating specific dermatologic diseases. Rejuvenation, scarring, wound healing, and other secondary conditions of skin damage were not investigated in this study. METHOD: Major databases, including PubMed, Scopus, and Web of Science, were meticulously searched for RCTs up to January 2024, focusing on regenerative medicine interventions for specific dermatologic disorders (such as androgenetic alopecia, vitiligo, alopecia areata, etc.). Key data extracted encompassed participant characteristics and sample sizes, types of regenerative therapy, treatment efficacy, and adverse events. RESULTS: In this systematic review, 64 studies involving a total of 2888 patients were examined. Women constituted 44.8% of the study population, while men made up 55.2% of the participants, with an average age of 27.64 years. The most frequently studied skin diseases were androgenetic alopecia (AGA) (45.3%) and vitiligo (31.2%). The most common regenerative methods investigated for these diseases were PRP and the transplantation of autologous epidermal melanocyte/keratinocyte cells, respectively. Studies reported up to 68.4% improvement in AGA and up to 71% improvement in vitiligo. Other diseases included in the review were alopecia areata, melasma, lichen sclerosus et atrophicus (LSA), inflammatory acne vulgaris, chronic telogen effluvium, erosive oral lichen planus, and dystrophic epidermolysis bullosa. Regenerative medicine was found to be an effective treatment option in all of these studies, along with other methods. The regenerative medicine techniques investigated in this study comprised the transplantation of autologous epidermal melanocyte/keratinocyte cells, isolated melanocyte transplantation, cell transplantation from hair follicle origins, melanocyte-keratinocyte suspension in PRP, conditioned media injection, a combination of PRP and basic fibroblast growth factor, intravenous injection of mesenchymal stem cells, concentrated growth factor, stromal vascular fraction (SVF), a combination of PRP and SVF, and preserving hair grafts in PRP. CONCLUSION: Regenerative medicine holds promise as a treatment for specific dermatologic disorders. To validate our findings, it is recommended to conduct numerous clinical trials focusing on various skin conditions. In our study, we did not explore secondary skin lesions like scars or ulcers. Therefore, assessing the effectiveness of this treatment method for addressing these conditions would necessitate a separate study.

Characterization of Skin Interfollicular Stem Cells and Early Transit Amplifying Cells during the Transition from Infants to Young Children.

In the interfollicular epidermis, keratinocyte stem cells (KSC) generate a short-lived population of transit amplifying (TA) cells that undergo terminal differentiation after several cell divisions. Recently, we isolated and characterized a highly proliferative keratinocyte cell population, named "early" TA (ETA) cell, representing the first KSC progenitor with exclusive features. This work aims to evaluate epidermis, with a focus on KSC and ETA cells, during transition from infancy to childhood. Reconstructed human epidermis (RHE) generated from infant keratinocytes is more damaged by UV irradiation, as compared to RHE from young children. Moreover, the expression of several differentiation and barrier genes increases with age, while the expression of genes related to stemness is reduced from infancy to childhood. The proliferation rate of KSC and ETA cells is higher in cells derived from infants' skin samples than of those derived from young children, as well as the capacity of forming colonies is more pronounced in KSC derived from infants than from young children's skin samples. Finally, infants-KSC show the greatest regenerative capacity in skin equivalents, while young children ETA cells express higher levels of differentiation markers, as compared to infants-ETA. KSC and ETA cells undergo substantial changes during transition from infancy to childhood. The study presents a novel insight into pediatric skin, and sheds light on the correlation between age and structural maturation of the skin.

Natural Product-Derived Compounds Targeting Keratinocytes and Molecular Pathways in Psoriasis Therapeutics.

Psoriasis is a chronic autoimmune inflammatory skin disorder that affects approximately 2-3% of the global population due to significant genetic predisposition. It is characterized by an uncontrolled growth and differentiation of keratinocytes, leading to the formation of scaly erythematous plaques. Psoriasis extends beyond dermatological manifestations to impact joints and nails and is often associated with systemic disorders. Although traditional treatments provide relief, their use is limited by potential side effects and the chronic nature of the disease. This review aims to discuss the therapeutic potential of keratinocyte-targeting natural products in psoriasis and highlight their efficacy and safety in comparison with conventional treatments. This review comprehensively examines psoriasis pathogenesis within keratinocytes and the various related signaling pathways (such as JAK-STAT and NF-κB) and cytokines. It presents molecular targets such as high-mobility group box-1 (HMGB1), dual-specificity phosphatase-1 (DUSP1), and the aryl hydrocarbon receptor (AhR) for treating psoriasis. It evaluates the ability of natural compounds such as luteolin, piperine, and glycyrrhizin to modulate psoriasis-related pathways. Finally, it offers insights into alternative and sustainable treatment options with fewer side effects.

Isolation, Characterization, and Utilization of Human Skin Basal and Suprabasal Epidermal Stem Cells.

Studying human skin biology can aid in comprehending the pathophysiology of skin diseases and developing novel cell-based therapies, including tissue engineering approaches. This chapter provides a comprehensive guide of methods to determine human skin samples from the perspective of their cellular compositions. We describe as useful technique the histological analysis of tissue sections. We further illustrate the biological characterization of isolated and cultured basal and suprabasal interfollicular keratinocytes by cell sorting, cytospin immunostaining, colony forming efficiency, and long-term dermo-epidermal organotypic cultures.

Keratinocyte differentiation factor 1 enhances cervical cancer cell viability and migration by activating the PI3K/AKT pathway.

BACKGROUND: The aim of This study is to investigate the effects of Keratinocyte differentiation factor 1 (KDF1) on cervical cancer cells and the underlying mechanisms. METHODS: The Gene Expression Profiling Interactive Analysis database was used to analyse KDF1 expression in cervical cancer and paracancerous tissue samples. The correlation between the expression of KDF1 and clinicopathological features was also analysed. Cervical cancer cells (HeLa cells) with KDF1 overexpression or knockdown were constructed. Reverse transcription polymerase chain reaction was used to detect the mRNA expression of KDF1 in cervical cancer tissues and cells. In different treatment groups of cervical cancer cells, protein expression of KDF1, cell viability, invasion, and migration were subsequently confirmed by western blotting, CCK-8 assay, transwell assay, and wound healing assay, respectively. A PI3K inhibitor (LY294002) was used to detect the effect of KDF1 on the phosphoinositide 3-kinase (PI3K)/Protein Kinase B (AKT) pathway. RESULTS: KDF1 was highly expressed in cervical cancer tissues and cell lines (p < 0.01), and was significantly associated with poor prognosis (p < 0.05). Knockdown of KDF1 in HeLa cells resulted in a significant decrease in cell proliferation, migration, and invasion, as well as phosphorylated PI3K (P-PI3K) and p-AKT levels (p < 0.01). However, KDF1 overexpression activated the PI3K/AKT pathway and significantly enhanced the malignant biological behaviour of cervical cancer cells (p < 0.01). Additionally, the PI3K inhibitor reduced the proliferation, invasion, and migration of HeLa cells overexpressing KDF1 (p < 0.01). CONCLUSION: KDF1 enhances cervical cancer viability and migration by activating the PI3K/AKT pathway, and may serve as a therapeutic target for patients with cervical cancer.

Cervical cancer is the fourth most common cancer in women worldwide and the leading cause of cancer-related deaths. Keratinocyte differentiation factor 1 (KDF1) is a protein-coding gene containing an unknown functional domain (DUF4656).In the present study, we detected the expression of KDF1 in cervical cancer tissues and cells. Furthermore, we investigated the effects of KDF1 on the proliferation, invasion, and migration of cervical cancer cells and the downstream mechanisms of KDF1.KDF1 promotes cervical cancer cell proliferation, invasion, and migration by activating the PI3K/AKT pathway, and KDF1 may be a biomarker for the treatment of cervical cancer.

The beneficial effects of ethanolic extract of Sargassum serratifolium in DNCB-induced mouse model of atopic dermatitis.

Atopic dermatitis is a chronic complex inflammatory skin disorder that requires sustainable treatment methods due to the limited efficacy of conventional therapies. Sargassum serratifolium, an algal species with diverse bioactive substances, is investigated in this study for its potential benefits as a therapeutic agent for atopic dermatitis. RNA sequencing of LPS-stimulated macrophages treated with ethanolic extract of Sargassum serratifolium (ESS) revealed its ability to inhibit a broad range of inflammation-related signaling, which was proven in RAW 264.7 and HaCaT cells. In DNCB-induced BALB/c or HR-1 mice, ESS treatment improved symptoms of atopic dermatitis within the skin, along with histological improvements such as reduced epidermal thickness and infiltration of mast cells. ESS showed a tendency to improve serum IgE levels and inflammation-related cytokine changes, while also improving the mRNA expression levels of Chi3l3, Ccr1, and Fcεr1a genes in the skin. Additionally, ESS compounds (sargachromanol (SCM), sargaquinoic acid (SQA), and sargahydroquinoic acid (SHQA)) mitigated inflammatory responses in LPS-treated RAW264.7 macrophages. In summary, ESS has an anti-inflammatory effect and improves atopic dermatitis, ESS may be applied as a therapeutics for atopic dermatitis.

MicroRNA-939 amplifies Staphylococcus aureus-induced matrix metalloproteinase expression in atopic dermatitis.

Background: Atopic dermatitis (AD) is a common chronic inflammatory skin diseases that seriously affects life quality of the patients. Staphylococcus aureus (S. aureus) colonization on the skin plays an important role in the pathogenesis of AD; however, the mechanism of how it modulates skin immunity to exacerbate AD remains unclear. MicroRNAs are short non-coding RNAs that act as post-transcriptional regulators of genes. They are involved in the pathogenesis of various inflammatory skin diseases. Methods: In this study, we established miRNA expression profiles for keratinocytes stimulated with heat-killed S. aureus (HKSA). The expression of miR-939 in atopic dermatitis patients was analyzed by fluorescence in situ hybridization (FISH). miR-939 mimic was transfected to human primary keratinocyte to investigate its impact on the expression of matrix metalloproteinase genes (MMPs) in vitro. Subsequently, miR-939, along with Polyplus transfection reagent, was administered to MC903-induced atopic dermatitis skin to assess its function in vivo. Results: MiR-939 was highly upregulated in HKSA-stimulated keratinocytes and AD lesions. In vitro studies revealed that miR-939 increased the expression of matrix metalloproteinase genes, including MMP1, MMP3, and MMP9, as well as the cell adhesion molecule ICAM1 in human primary keratinocytes. In vivo studies indicated that miR-939 increased the expression of matrix metalloproteinases to promote the colonization of S. aureus and exacerbated S. aureus-induced AD-like skin inflammation. Conclusions: Our work reveals miR-939 is an important regulator of skin inflammation in AD that could be used as a potential therapeutic target for AD.

IL-17A and TNF-α-induced Dectin-1 expression may promote keratinocyte proliferation in psoriatic lesions.

Psoriasis is a common skin disease with a high recurrence rate. Aberrant keratinocyte proliferation is a significant pathogenic characteristic of psoriatic lesions, and studies have revealed that the development of psoriasis is significantly influenced by pro-inflammatory cytokines, such as IL-17A and TNF-α. Biologics targeting these cytokines have been widely used in psoriasis treatment and achieve remarkable effects, however, the underlying mechanism of how IL-17A and TNF-α specifically regulate keratinocyte proliferation has not been fully elucidated. Dectin-1 is an essential membrane protein that is directly related to the immune microenvironment and the proliferation of multiple cell types. To elucidate how IL-17A and TNF-α may promote keratinocyte proliferation in psoriatic lesions and whether Dectin-1 is involved. The expression of Dectin-1 in keratinocytes from psoriatic lesions was detected by real-time PCR, western blot and immunofluorescence. Correlation analysis and cytological experiments were then performed to determine the relationship between Dectin-1 and IL-17A/TNF-α in psoriatic lesions. Finally, we investigated the signalling pathway through which Dectin-1 may promote keratinocyte proliferation. Dectin-1 was significantly increased in keratinocytes from psoriatic lesions. Moreover, IL-17A and TNF-α effectively induced the expression of Dectin-1 in HaCaT cells, which was shown to activate the Syk/NF-κB signalling pathway and promote the proliferation of keratinocytes. IL-17A and TNF-α may promote the proliferation of keratinocytes in psoriatic lesions through induction of Dectin-1, indicating that Dectin-1 could be a potential therapeutic target for the treatment of psoriasis.

Detection of invisible biological traces in relation to the physicochemical properties of substrates surfaces in forensic casework.

Touch DNA, which can be found at crime scenes, consists of invisible biological traces deposited through a person's skin's contact with an object or another person. Many factors influence touch DNA transfer, including the "destination" substrate's surface. The latter's physicochemical characteristics (wettability, roughness, surface energy, etc.) will impact touch DNA deposition and persistence on a substrate. We selected a representative panel of substrates from objects found at crime scenes (glass, polystyrene, tiles, raw wood, etc.) to investigate the impact of these characteristics on touch DNA deposition and detection. These were shown to impact cell deposition, morphology, retention, and subsequent touch DNA genetic analysis. Interestingly, cell-derived fragments found within keratinocyte cells and fingermarks using in vitro touch DNA models could be successfully detected whichever the substrates' physicochemistry by targeting cellular proteins and carbohydrates for two months, indoors and outdoors. However, swabbing and genetic analyses of such mock traces from different substrates produced informative profiles mainly for substrates with the highest surface free energy and therefore the most hydrophilic. The substrates' intrinsic characteristics need to be considered to better understand both the transfer and persistence of biological traces, as well as their detection and collection, which require an appropriate methodology and sampling device to get informative genetic profiles.