Function and regulation of AP-1 subunits in skin physiology and pathology

Development of pluripotent stem cell-derived epidermal organoids that generate effective extracellular vesicles in skin regeneration

Cellular skin substitutes such as epidermal constructs have been developed for various applications, including wound healing and skin regeneration. These cellular models are mostly derived from primary cells such as keratinocytes and fibroblasts in a two-dimensional (2D) state, and further development of three-dimensional (3D) cultured organoids is needed to provide insight into the in vivo epidermal phenotype and physiology. Here, we report the development of epidermal organoids (EpiOs) generated from induced pluripotent stem cells (iPSCs) as a novel epidermal construct and its application as a source of secreted biomolecules recovered by extracellular vesicles (EVs) that can be utilized for cell-free therapy of regenerative medicine. Differentiated iPSC-derived epidermal organoids (iEpiOs) are easily cultured and expanded through multiple organoid passages, while retaining molecular and functional features similar to in vivo epidermis. These mature iEpiOs contain epidermal stem cell populations and retain the ability to further differentiate into other skin compartment lineages, such as hair follicle stem cells. By closely recapitulating the epidermal structure, iEpiOs are expected to provide a more relevant microenvironment to influence cellular processes and therapeutic response. Indeed, iEpiOs can generate high-performance EVs containing high levels of the angiogenic growth factor VEGF and miRNAs predicted to regulate cellular processes such as proliferation, migration, differentiation, and angiogenesis. These EVs contribute to target cell proliferation, migration, and angiogenesis, providing a promising therapeutic tool for in vivo wound healing. Overall, the newly developed iEpiOs strategy as an organoid-based approach provides a powerful model for studying basic and translational skin research and may also lead to future therapeutic applications using iEpiOs-secreted EVs.

Anti-inflammatory, Antioxidative, and Moisturizing Effects of Oxyceros horridus Lour. Ethanol Extract in Human Keratinocytes via the p38 Signaling Pathway

Skin is the largest and outermost organ in the human body; it serves as a vital defense mechanism against various external threats. Therefore, it is crucial to maintain its health through protection against harmful substances and adequate moisture levels. This study investigates the anti-inflammatory, antioxidant, and moisturizing properties of Oxyceros horridus Lour. (Oh-EE) in human keratinocytes. Oh-EE demonstrates potent antioxidant activity and effectively protects against oxidative stress induced by external stimuli such as UVB radiation and H2O2. Additionally, it exhibits significant anti-inflammatory effects proven by its ability to downregulate the expression of pro-inflammatory cytokines, namely COX-2 and IL-6. The study also explores the involvement of the AP-1 pathway, highlighting the ability of Oh-EE to suppress the expression of p38 and its upstream regulator, MKK3/6, under UVB-induced conditions. Interestingly, Oh-EE can activate the AP-1 pathway in the absence of external triggers. Furthermore, Oh-EE enhances skin moisture by upregulating the expression of key genes involved in skin hydration, namely HAS3 and FLG. These findings underscore the potential of Oh-EE as a versatile ingredient in skincare formulations, providing a range of skin benefits. Further research is warranted to comprehensively understand the underlying mechanisms through which Oh-EE exerts its effects.

Role of Fra-2 in cancer

Fos-related antigen-2 (Fra-2) is the most recently discovered member of the Fos family and, by dimerizing with Jun proteins, forms the activator protein 1 (AP-1) transcription factor. By inducing or repressing the transcription of several target genes, Fra-2 is critically involved in the modulation of cell response to a variety of extracellular stimuli, stressors and intracellular changes. In physiological conditions, Fra-2 has been found to be ubiquitously expressed in human cells, regulating differentiation and homeostasis of bone, muscle, nervous, lymphoid and other tissues. While other AP-1 members, like Jun and Fos, are well characterized, studies of Fra-2 functions in cancer are still at an early stage. Due to the lack of a trans-activating domain, which is present in other Fos proteins, it has been suggested that Fra-2 might inhibit cell transformation, eventually exerting an anti-tumor effect. In human malignancies, however, Fra-2 activity is enhanced (or induced) by dysregulation of microRNAs, oncogenes and extracellular signaling, suggesting a multifaceted role. Therefore, Fra-2 can promote or prevent transformation, proliferation, migration, epithelial-mesenchymal transition, drug resistance and metastasis formation in a tumor- and context-dependent manner. Intriguingly, recent data reports that Fra-2 is also expressed in cancer associated cells, contributing to the intricate crosstalk between neoplastic and non-neoplastic cells, that leads to the evolution and remodeling of the tumor microenvironment. In this review we summarize three decades of research on Fra-2, focusing on its oncogenic and anti-oncogenic effects in tumor progression and dissemination.

Transparent silk fibroin film-facilitated infected-wound healing through antibacterial, improved fibroblast adhesion and immune modulation

The clinical application of regenerated silk fibroin (RSF) films for wound treatment is restricted by its undesirable mechanical properties and lack of antibacterial activity. Herein, different pluronic polymers were introduced to optimize their mechanical properties and the RSF film with 2.5% pluronic F127 (RSFPF127) stood out to address the above issues owing to its satisfactory mechanical properties, hydrophilicity, and transmittance. Diverse antibacterial agents (curcumin, Ag nanoparticles, and antimicrobial peptide KR-12) were separately encapsulated in RSFPF127 to endow it with antibacterial activity. In vitro experiments revealed that the medicated RSFPF127 could persistently release drugs and had desirable bioactivities toward killing bacteria, promoting fibroblast adhesion, and modulating macrophage polarization. In vivo experiments revealed that medicated RSFPF127 not only eradicated methicillin-resistant Staphylococcus aureus in the wound area and inhibited inflammatory responses, but also facilitated angiogenesis and re-epithelialization, regardless of the types of antibacterial agents, thus accelerating the recovery of infected wounds. These results demonstrate that RSFPF127 is an ideal matrix platform to load different types of drugs for application as wound dressings.

Tick extracellular vesicles impair epidermal homeostasis through immune-epithelial networks during hematophagy

Hematophagous ectoparasites, such as ticks, rely on impaired wound healing for skin attachment and blood feeding. Wound healing has been extensively studied through the lens of inflammatory disorders and cancer, but limited attention has been given to arthropod-borne diseases. Here, we used orthogonal approaches combining single-cell RNA sequencing (scRNAseq), flow cytometry, murine genetics, and intravital microscopy to demonstrate how tick extracellular vesicles (EVs) disrupt networks involved in tissue repair. Impairment of EVs through silencing of the SNARE protein vamp33 negatively impacted ectoparasite feeding and survival in three medically relevant tick species, including Ixodes scapularis. Furthermore, I. scapularis EVs affected epidermal γδ T cell frequencies and co-receptor expression, which are essential for keratinocyte function. ScRNAseq analysis of the skin epidermis in wildtype animals exposed to vamp33-deficient ticks revealed a unique cluster of keratinocytes with an overrepresentation of pathways connected to wound healing. This biological circuit was further implicated in arthropod fitness when tick EVs inhibited epithelial proliferation through the disruption of phosphoinositide 3-kinase activity and keratinocyte growth factor levels. Collectively, we uncovered a tick-targeted impairment of tissue repair via the resident γδ T cell-keratinocyte axis, which contributes to ectoparasite feeding.

Induced skin aging by blue-light irradiation in human skin fibroblasts via TGF-β, JNK and EGFR pathways

BACKGROUND

Studies indicate that blue light (BL) irradiation can damage human skins, but the impact of BL irradiation on skin aging is unknown.

OBJECTIVES

This study aimed to give an insight to phenotypic characteristics and molecular mechanism of blue light-induced skin aging, and thus provide a theoretical basis for the precise protection of photodermatosis.

METHODS

The effect of BL on skin photoaging in mice was evaluated by non-invasive measurement equipment and histopathology analysis. The effect of BL irradiation on the proliferation of HFF-1 cells was detected by the Real-Time Cell Analyzer. The expression and protein levels of genes associated with skin aging were examined.

RESULTS

Our studies indicated photoaging caused by BL irradiation, including collagen disorder and increased MMP1. BL irradiation also inhibited cell proliferation and collagen expression in human skin fibroblasts by inhibiting TGF-β signaling pathway, based on in vitro experiments. Importantly, BL irradiation promoted the degradation of collagen by increasing MMP1 activated by the JNK/c-Jun and EGFR pathways. Moreover, ROS levels were significantly increased after BL irradiation in human skin fibroblasts. Yet, the transcriptional change in human skin fibroblasts caused by BL irradiation was unable to be completely restored by ROS scavenger.

CONCLUSION

BL irradiation down-regulated expression of type I collagen genes and up-regulated MMP1 expression to inhibit the proliferation of human skin fibroblasts. Multiple key pathways including TGF-β, JNK, and EGFR signaling were involved in BL-induced skin aging. Our results provide theoretical bases for the protection of photoaging caused by BL irradiation.

Identification and analysis of cellular senescence-associated signatures in diabetic kidney disease by integrated bioinformatics analysis and machine learning

Background

Diabetic kidney disease (DKD) is a common complication of diabetes that is clinically characterized by progressive albuminuria due to glomerular destruction. The etiology of DKD is multifactorial, and numerous studies have demonstrated that cellular senescence plays a significant role in its pathogenesis, but the specific mechanism requires further investigation.

Methods

This study utilized 5 datasets comprising 144 renal samples from the Gene Expression Omnibus (GEO) database. We obtained cellular senescence-related pathways from the Molecular Signatures Database and evaluated the activity of senescence pathways in DKD patients using the Gene Set Enrichment Analysis (GSEA) algorithm. Furthermore, we identified module genes related to cellular senescence pathways through Weighted Gene Co-Expression Network Analysis (WGCNA) algorithm and used machine learning algorithms to screen for hub genes related to senescence. Subsequently, we constructed a cellular senescence-related signature (SRS) risk score based on hub genes using the Least Absolute Shrinkage and Selection Operator (LASSO), and verified mRNA levels of hub genes by RT-PCR in vivo. Finally, we validated the relationship between the SRS risk score and kidney function, as well as their association with mitochondrial function and immune infiltration.

Results

The activity of cellular senescence-related pathways was found to be elevated among DKD patients. Based on 5 hub genes (LIMA1, ZFP36, FOS, IGFBP6, CKB), a cellular senescence-related signature (SRS) was constructed and validated as a risk factor for renal function decline in DKD patients. Notably, patients with high SRS risk scores exhibited extensive inhibition of mitochondrial pathways and upregulation of immune cell infiltration.

Conclusion

Collectively, our findings demonstrated that cellular senescence is involved in the process of DKD, providing a novel strategy for treating DKD.

Regulation of chromatin organization during animal regeneration

Activation of regeneration upon tissue damages requires the activation of many developmental genes responsible for cell proliferation, migration, differentiation, and tissue patterning. Ample evidence revealed that the regulation of chromatin organization functions as a crucial mechanism for establishing and maintaining cellular identity through precise control of gene transcription. The alteration of chromatin organization can lead to changes in chromatin accessibility and/or enhancer-promoter interactions. Like embryogenesis, each stage of tissue regeneration is accompanied by dynamic changes of chromatin organization in regeneration-responsive cells. In the past decade, many studies have been conducted to investigate the contribution of chromatin organization during regeneration in various tissues, organs, and organisms. A collection of chromatin regulators were demonstrated to play critical roles in regeneration. In this review, we will summarize the progress in the understanding of chromatin organization during regeneration in different research organisms and discuss potential common mechanisms responsible for the activation of regeneration response program.

Matrix Metalloproteinases Contribute to the Calcification Phenotype in Pseudoxanthoma Elasticum

Ectopic calcification and dysregulated extracellular matrix remodeling are prominent hallmarks of the complex heterogenous pathobiochemistry of pseudoxanthoma elasticum (PXE). The disease arises from mutations in ABCC6, an ATP-binding cassette transporter expressed predominantly in the liver. Neither its substrate nor the mechanisms by which it contributes to PXE are completely understood. The fibroblasts isolated from PXE patients and Abcc6-/- mice were subjected to RNA sequencing. A group of matrix metalloproteinases (MMPs) clustering on human chromosome 11q21-23, respectively, murine chromosome 9, was found to be overexpressed. A real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay and immunofluorescent staining confirmed these findings. The induction of calcification by CaCl2 resulted in the elevated expression of selected MMPs. On this basis, the influence of the MMP inhibitor Marimastat (BB-2516) on calcification was assessed. PXE fibroblasts (PXEFs) exhibited a pro-calcification phenotype basally. PXEF and normal human dermal fibroblasts responded with calcium deposit accumulation and the induced expression of osteopontin to the addition of Marimastat to the calcifying medium. The raised MMP expression in PXEFs and during cultivation with calcium indicates a correlation of ECM remodeling and ectopic calcification in PXE pathobiochemistry. We assume that MMPs make elastic fibers accessible to controlled, potentially osteopontin-dependent calcium deposition under calcifying conditions.

Protective Effect of Castanopsis sieboldii Extract against UVB-Induced Photodamage in Keratinocytes

Ultraviolet B (UVB) rays disrupt the skin by causing photodamage via processes such as reactive oxygen species (ROS) production, endoplasmic reticulum (ER) stress, DNA damage, and/or collagen degradation. Castanopsis sieboldii is an evergreen tree native to the southern Korean peninsula. Although it is known to have antioxidant and anti-inflammatory effects, its protective effect against photodamage in keratinocytes has not been investigated. Thus, in the present study, we investigated the effect of 70% ethanol extract of C. sieboldii leaf (CSL3) on UVB-mediated skin injuries and elucidated the underlying molecular mechanisms. CSL3 treatment restored the cell viability decreased by UVB irradiation. Moreover, CSL3 significantly inhibited UVB- or tert-butyl hydroperoxide-mediated ROS generation in HaCaT cells. ER stress was inhibited, whereas autophagy was upregulated by CSL3 treatment against UVB irradiation. Additionally, CSL3 increased collagen accumulation and cell migration, which were decreased by UVB exposure. Notably, epigallocatechin gallate, the major component of CSL3, improved the cell viability decreased by UVB irradiation through regulation of ER stress and autophagy. Conclusively, CSL3 may represent a promising therapeutic candidate for the treatment of UVB-induced skin damage.

Transcriptome Sequencing Reveals the Mechanism behind Chemically Induced Oral Mucositis in a 3D Cell Culture Model

Oral mucositis is a common side effect of cancer treatment, and in particular of treatment with the mTORC1 inhibitor everolimus. Current treatment methods are not efficient enough and a better understanding of the causes and mechanisms behind oral mucositis is necessary to find potential therapeutic targets. Here, we treated an organotypic 3D oral mucosal tissue model consisting of human keratinocytes grown on top of human fibroblasts with a high or low dose of everolimus for 40 or 60 h and investigated (1) the effect of everolimus on microscopic sections of the 3D cell culture for evidence of morphologic changes and (2) changes in the transcriptome by high throughput RNA-Seq analysis. We show that the most affected pathways are cornification, cytokine expression, glycolysis, and cell proliferation and we provide further details. This study provides a good resource towards a better understanding of the development of oral mucositis. It gives a detailed overview of the different molecular pathways that are involved in mucositis. This in turn provides information about potential therapeutic targets, which is an important step towards preventing or managing this common side effect of cancer treatment.

miR-1246-overexpressing exosomes suppress UVB-induced photoaging via regulation of TGF-β/Smad and attenuation of MAPK/AP-1 pathway

Stem cell therapy is widely employed for the treatment of skin diseases, especially in skin rejuvenation. Exosomes derived from stem cells have been demonstrated to possess anti-photoaging effects; however, the precise components within exosomes that are responsible for this effect remain unknown. Previously, miR-1246 was found to be one of the most abundant nucleic acids in adipose-derived stem cells (ADSCs)-derived exosomes. This study examined whether miR-1246 was the major therapeutic agent employed by ADSCs to protect against UVB-induced photoaging. Lentivirus infection was used to obtain miR-1246-overexpressing ADSCs and exosomes. We then determined the anti-photoaging effects of miR-1246-overexpressing exosomes (OE-EX) on both UVB-irradiated human skin fibroblasts (HSFs) and Kunming mice. The results showed that OE-EX could significantly decrease MMP-1 by inhibiting the MAPK/AP-1 signaling pathway. Meanwhile, OE-EX markedly increased procollagen type I secretion by activating the TGF-β/Smad pathway. OE-EX also exhibited an anti-inflammatory effect by preventing the UVB-induced degradation of IκB-α and NF-κB overexpression. Animal experiments demonstrated that OE-EX could reduce UVB-induced wrinkle formation, epidermis thickening, and the loss of collagen fibers reduction in Kunming mice. The combined results suggested that miR-1246 is the key component within ADSCs-derived exosomes that protects against UVB-induced skin photoaging.

Development of a Vascularized Human Skin Equivalent with Hypodermis for Photoaging Studies

Photoaging is an important extrinsic aging factor leading to altered skin morphology and reduced function. Prior work has revealed a connection between photoaging and loss of subcutaneous fat. Currently, primary models for studying this are in vivo (human samples or animal models) or in vitro models, including human skin equivalents (HSEs). In vivo models are limited by accessibility and cost, while HSEs typically do not include a subcutaneous adipose component. To address this, we developed an "adipose-vascular" HSE (AVHSE) culture method, which includes both hypodermal adipose and vascular cells. Furthermore, we tested AVHSE as a potential model for hypodermal adipose aging via exposure to 0.45 ± 0.15 mW/cm² 385 nm light (UVA). One week of 2 h daily UVA exposure had limited impact on epidermal and vascular components of the AVHSE, but significantly reduced adiposity by approximately 50%. Overall, we have developed a novel method for generating HSE that include vascular and adipose components and demonstrated potential as an aging model using photoaging as an example.

Organotypic cultures as aging associated disease models

Aging remains a primary risk factor for a host of diseases, including leading causes of death. Aging and associated diseases are inherently multifactorial, with numerous contributing factors and phenotypes at the molecular, cellular, tissue, and organismal scales. Despite the complexity of aging phenomena, models currently used in aging research possess limitations. Frequently used in vivo models often have important physiological differences, age at different rates, or are genetically engineered to match late disease phenotypes rather than early causes. Conversely, routinely used in vitro models lack the complex tissue-scale and systemic cues that are disrupted in aging. To fill in gaps between in vivo and traditional in vitro models, researchers have increasingly been turning to organotypic models, which provide increased physiological relevance with the accessibility and control of in vitro context. While powerful tools, the development of these models is a field of its own, and many aging researchers may be unaware of recent progress in organotypic models, or hesitant to include these models in their own work. In this review, we describe recent progress in tissue engineering applied to organotypic models, highlighting examples explicitly linked to aging and associated disease, as well as examples of models that are relevant to aging. We specifically highlight progress made in skin, gut, and skeletal muscle, and describe how recently demonstrated models have been used for aging studies or similar phenotypes. Throughout, this review emphasizes the accessibility of these models and aims to provide a resource for researchers seeking to leverage these powerful tools.

Systematic evaluation of irinotecan-induced intestinal mucositis based on metabolomics analysis

Chemotherapy-induced intestinal mucositis (CIM) is a major dose-limiting side effect of chemotherapy, especially in regimens containing irinotecan (CPT-11). Several studies on the pathologic mechanisms of CIM focused on both the genomics and molecular pathways triggered by chemotherapy. However, systematic evaluation of metabolomic analysis in irinotecan-induced intestinal mucositis (IIM) has not been investigated. This study aimed to comprehensively analyze metabolite changes in main tissues of IIM mouse models. Male ICR mice were assigned to two groups: the model group (n = 11) treated with CPT-11 (20 mg/kg daily; i.p.) and the control group (n= 11) with solvent for 9 days. Gas chromatography-mass spectrometry (GC-MS) was used to investigate the metabolic alterations in the serum, intestinal, colonic, hepatic, and splenic samples of mice between two groups by multivariate statistical analyses, including GC–MS data processing, pattern recognition analysis, and pathway analysis. Forty-six metabolites, including hydrocarbons, amino acids, lipids, benzenoids, hydroxy acids, and amines, had significant changes in levels in tissues and sera of IIM mouse models. The most important pathways related to the identified metabolites were the glycerolipid metabolism in the colon and aminoacyl-tRNA biosynthesis; glycine, serine, and threonine metabolism; and glyoxylate and dicarboxylate metabolism in the liver. Our study firstly provided a comprehensive and systematic view of metabolic alterations of IIM using GC-MS analysis. The characterizations of metabolic changes could offer profound and theoretical insight into exploring new biomarkers for diagnosis and treatment of IIM.

FRA1:c-JUN:HDAC1 complex down-regulates filaggrin expression upon TNFα and IFNγ stimulation in keratinocytes

Filaggrin (FLG), an essential structural protein for skin barrier function, is down-regulated under chronic inflammatory conditions, leading to disruption of the skin barrier. However, the detailed molecular mechanisms of how FLG changes in the context of chronic inflammation are poorly understood. Here, we identified the molecular mechanisms by which inflammatory cytokines inhibit FLG expression in the skin. We found that the AP1 response element within the -343/+25 of the FLG promoter was necessary for TNFα + IFNγ-induced down-regulation of FLG promoter activity. Using DNA affinity precipitation assay, we observed that AP1 subunit composition binding to the FLG promoter was altered from c-FOS:c-JUN (at the early time) to FRA1:c-JUN (at the late time) in response to TNFα + IFNγ stimulation. Knockdown of FRA1 or c-JUN abrogated TNFα + IFNγ-induced FLG suppression. Histone deacetylase (HDAC) 1 interacted with FRA1:c-JUN under TNFα + IFNγ stimulation. Knockdown of HDAC1 abrogated the inhibitory effect of TNFα + IFNγ on FLG expression. The altered expression of FLG, FRA1, c-JUN, and HDAC1 was confirmed in mouse models of 2,4-dinitrochlorobenzene-induced atopic dermatitis and imiquimod-induced psoriasis. Thus, the current study demonstrates that TNFα + IFNγ stimulation suppresses FLG expression by promoting the FRA1:c-JUN:HDAC1 complex. This study provides insight into future therapeutic strategies targeting the FRA1:c-JUN:HDAC1 complex to restore impaired FLG expression in chronic skin inflammation.

Phylogenetic and Expression Analysis of Fos Transcription Factors in Zebrafish

Members of the FOS protein family regulate gene expression responses to a multitude of extracellular signals and are dysregulated in several pathological states. Whilst mouse genetic models have provided key insights into the tissue-specific functions of these proteins in vivo, little is known about their roles during early vertebrate embryonic development. This study examined the potential of using zebrafish as a model for such studies and, more broadly, for investigating the mechanisms regulating the functions of Fos proteins in vivo. Through phylogenetic and sequence analysis, we identified six zebrafish FOS orthologues, fosaa, fosab, fosb, fosl1a, fosl1b, and fosl2, which show high conservation in key regulatory domains and post-translational modification sites compared to their equivalent human proteins. During embryogenesis, zebrafish fos genes exhibit both overlapping and distinct spatiotemporal patterns of expression in specific cell types and tissues. Most fos genes are also expressed in a variety of adult zebrafish tissues. As in humans, we also found that expression of zebrafish FOS orthologs is induced by oncogenic BRAF-ERK signalling in zebrafish melanomas. These findings suggest that zebrafish represent an alternate model to mice for investigating the regulation and functions of Fos proteins in vertebrate embryonic and adult tissues, and cancer.

The Role of Transcription Factor PPAR-γ in the Pathogenesis of Psoriasis, Skin Cells, and Immune Cells

The peroxisome proliferator-activated receptor PPAR-γ is one of three PPAR nuclear receptors that act as ligand-activated transcription factors. In immune cells, the skin, and other organs, PPAR-γ regulates lipid, glucose, and amino acid metabolism. The receptor translates nutritional, pharmacological, and metabolic stimuli into the changes in gene expression. The activation of PPAR-γ promotes cell differentiation, reduces the proliferation rate, and modulates the immune response. In the skin, PPARs also contribute to the functioning of the skin barrier. Since we know that the route from identification to the registration of drugs is long and expensive, PPAR-γ agonists already approved for other diseases may also represent a high interest for psoriasis. In this review, we discuss the role of PPAR-γ in the activation, differentiation, and proliferation of skin and immune cells affected by psoriasis and in contributing to the pathogenesis of the disease. We also evaluate whether the agonists of PPAR-γ may become one of the therapeutic options to suppress the inflammatory response in lesional psoriatic skin and decrease the influence of comorbidities associated with psoriasis.

Mechanical Stretch Induced Skin Regeneration: Molecular and Cellular Mechanism in Skin Soft Tissue Expansion

Skin soft tissue expansion is one of the most basic and commonly used techniques in plastic surgery to obtain excess skin for a variety of medical uses. However, skin soft tissue expansion is faced with many problems, such as long treatment process, poor skin quality, high retraction rate, and complications. Therefore, a deeper understanding of the mechanisms of skin soft tissue expansion is needed. The key to skin soft tissue expansion lies in the mechanical stretch applied to the skin by an inflatable expander. Mechanical stimulation activates multiple signaling pathways through cellular adhesion molecules and regulates gene expression profiles in cells. Meanwhile, various types of cells contribute to skin expansion, including keratinocytes, dermal fibroblasts, and mesenchymal stem cells, which are also regulated by mechanical stretch. This article reviews the molecular and cellular mechanisms of skin regeneration induced by mechanical stretch during skin soft tissue expansion.

The family of kallikrein-related peptidases and kinin peptides as modulators of epidermal homeostasis

The epidermis is the outermost skin layer and is part of one of the largest organs in the body; it is supported by the dermis, a network of fibrils, blood vessels, pilosebaceous units, sweat glands, nerves, and cells. The skin as a whole is a protective shield against numerous noxious agents, including microorganisms and chemical and physical factors. These functions rely on the activity of multiple growth factors, peptide hormones, proteases, and specific signaling pathways that are triggered by the activation of distinct types of receptors sited in the cell membranes of the various cell types present in the skin. The human kallikrein family comprises a large group of 15 serine proteases synthesized and secreted by different types of epithelial cells throughout the body, including the skin. At this site, they initiate a proteolytic cascade that generates the active forms of the proteases, some of which regulate skin desquamation, activation of cytokines, and antimicrobial peptides. Kinin peptides are formed by the action of plasma and tissue kallikreins on kininogens, two plasma proteins produced in the liver and other organs. Although kinins are well known for their proinflammatory abilities, in the skin they are also considered important modulators of keratinocyte differentiation. In this review, we summarize the contributions of the kallikreins and kallikrein-related peptidases family and those of kinins and their receptors in skin homeostasis, with special emphasis on their pathophysiological role.

Melatonin Prevents UVB-Induced Skin Photoaging by Inhibiting Oxidative Damage and MMP Expression through JNK/AP-1 Signaling Pathway in Human Dermal Fibroblasts

Exposure to ultraviolet (UV) irradiation causes damage to the skin and induces photoaging. UV irradiation stimulates production of reactive oxygen/nitrogen species, which results in activation of epidermal growth factor receptor (EGFR) and mitogen-activated protein kinases (MAPK) in fibroblasts. MAPKs are responsible for activation of activator protein-1 (AP-1), which subsequently upregulates expression of matrix metalloproteinases (MMPs). Melatonin is a potent free radical scavenger which is known to have photoprotective effects. The aim of this study is to investigate the underlying molecular mechanisms for the photoprotective effects of melatonin in UVB-irradiated primary human dermal fibroblasts (HDFs) in terms of EGFR activation, oxidative/nitrosative damage, JNK/AP-1 activation, MMP activities, and the levels of tissue inhibitors of metalloproteinase-1 (TIMP-1) and type I procollagen (PIP-C). In this study, HDFs were pretreated with 1 μM of melatonin and then irradiated with 0.1 J/cm² of UVB. Changes in the molecules were analyzed at different time points. Melatonin inhibited UVB-induced oxidative/nitrosative stress damage by reducing malondialdehyde, the ratio of oxidized/reduced glutathione, and nitrotyrosine. Melatonin downregulated UV-induced activation of EGFR and the JNK/AP-1 signaling pathway. UVB-induced activities of MMP-1 and MMP-3 were decreased and levels of TIMP-1 and PIP-C were increased by melatonin. These findings suggest that melatonin can protect against the adverse effects of UVB radiation by inhibiting MMP-1 and MMP-3 activity and increasing TIMP-1 and PIP-C levels, probably through the suppression of oxidative/nitrosative damage, EGFR, and JNK/AP-1 activation in HDFs.

Role of Phytochemicals in Skin Photoprotection via Regulation of Nrf2

Ethnopharmacological studies have become increasingly valuable in the development of botanical products and their bioactive phytochemicals as novel and effective preventive and therapeutic strategies for various diseases including skin photoaging and photodamage-related skin problems including abnormal pigmentation and inflammation. Exploring the roles of phytochemicals in mitigating ultraviolet radiation (UVR)-induced skin damage is thus of importance to offer insights into medicinal and ethnopharmacological potential for development of novel and effective photoprotective agents. UVR plays a role in the skin premature aging (or photoaging) or impaired skin integrity and function through triggering various biological responses of skin cells including apoptosis, oxidative stress, DNA damage and inflammation. In addition, melanin produced by epidermal melanocytes play a protective role against UVR-induced skin damage and therefore hyperpigmentation mediated by UV irradiation could reflect a sign of defensive response of the skin to stress. However, alteration in melanin synthesis may be implicated in skin damage, particularly in individuals with fair skin. Oxidative stress induced by UVR contributes to the process of skin aging and inflammation through the activation of related signaling pathways such as the mitogen-activated protein kinase (MAPK)/activator protein-1 (AP-1), the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt), the nuclear factor kappa B (NF-κB) and the signal transducer and activator of transcription (STAT) in epidermal keratinocytes and dermal fibroblasts. ROS formation induced by UVR also plays a role in regulation of melanogenesis in melanocytes via modulating MAPK, PI3K/Akt and the melanocortin 1 receptor (MC1R)-microphthalmia-associated transcription factor (MITF) signaling cascades. Additionally, nuclear factor erythroid 2-related factor 2 (Nrf2)-regulated antioxidant defenses can affect the major signaling pathways involved in regulation of photoaging, inflammation associated with skin barrier dysfunction and melanogenesis. This review thus highlights the roles of phytochemicals potentially acting as Nrf2 inducers in improving photoaging, inflammation and hyperpigmentation via regulation of cellular homeostasis involved in skin integrity and function. Taken together, understanding the role of phytochemicals targeting Nrf2 in photoprotection could provide an insight into potential development of natural products as a promising strategy to delay skin photoaging and improve skin conditions.

Inflammation: A New Look at an Old Problem

Pro-inflammatory stress is inherent in any cells that are subject to damage or threat of damage. It is defined by a number of universal components, including oxidative stress, cellular response to DNA damage, unfolded protein response to mitochondrial and endoplasmic reticulum stress, changes in autophagy, inflammasome formation, non-coding RNA response, formation of an inducible network of signaling pathways, and epigenetic changes. The presence of an inducible receptor and secretory phenotype in many cells is the cause of tissue pro-inflammatory stress. The key phenomenon determining the occurrence of a classical inflammatory focus is the microvascular inflammatory response (exudation, leukocyte migration to the alteration zone). This same reaction at the systemic level leads to the development of life-critical systemic inflammation. From this standpoint, we can characterize the common mechanisms of pathologies that differ in their clinical appearance. The division of inflammation into alternative variants has deep evolutionary roots. Evolutionary aspects of inflammation are also described in the review. The aim of the review is to provide theoretical arguments for the need for an up-to-date theory of the relationship between key human pathological processes based on the integrative role of the molecular mechanisms of cellular and tissue pro-inflammatory stress.

Monosodium urate crystals regulate a unique JNK-dependent macrophage metabolic and inflammatory response

Monosodium urate crystals (MSUc) induce inflammation in vivo without prior priming, raising the possibility of an initial cell-autonomous phase. Here, using genome-wide transcriptomic analysis and biochemical assays, we demonstrate that MSUc alone induce a metabolic-inflammatory transcriptional program in non-primed human and murine macrophages that is markedly distinct to that induced by LPS. Genes uniquely upregulated in response to MSUc belong to lipid and amino acid metabolism, glycolysis, and SLC transporters. This upregulation leads to a metabolic rewiring in sera from individuals and mice with acute gouty arthritis. Mechanistically, the initiating inflammatory-metabolic changes in acute gout flares are regulated through a persistent expression and increased binding of JUN to the promoter of target genes through JNK signaling-but not P38-in a process that is different than after LPS stimulation and independent of inflammasome activation. Finally, pharmacological JNK inhibition limits MSUc-induced inflammation in animal models of acute gouty inflammation.

Exosomes secreted by hypoxia-preconditioned adipose-derived mesenchymal stem cells reduce neuronal apoptosis in rats with spinal cord injury

Neuronal death is the main cause of nerve function impairment after spinal cord injury (SCI). Exosome-based therapy has become a novel strategy for tissue injury repair. We designed a method to treat SCI using exosomes secreted by adipose tissue-derived stromal cells (ADSCs) under hypoxic conditions. We established a neuronal oxygen-glucose deprivation and reperfusion (OGD/R) model in vitro to simulate the hypoxic environment after SCI. We observed that exosomes derived from hypoxia-conditioned ADSCs (Hypo-exos) significantly reduced neuronal apoptosis after OGD. By establishing a rat SCI model, we found that Hypo-exos can significantly reduce the formation of cavities in the injured area and improve the functional recovery of the hind limbs of rats after injury. To explore the molecular mechanism, we conducted miRNA sequencing analysis of exosomes. Through RT-PCR, dual luciferase reporter assays and signaling pathway chip analysis, we determined that miR-499a-5p regulates the JNK3/c-jun-apoptotic signaling pathway by targeting JNK3. Furthermore, we verified the expression of the key proteins in the JNK3/c-jun-apoptotic signaling pathway by immunofluorescence and western blotting. These results support the hypothesis that Hypo-exos can reduce neuronal apoptosis after SCI and may provide new methods to treat SCI.

Protective effects of Quercus acuta Thunb. fruit extract against UVB-induced photoaging through ERK/AP-1 signaling modulation in human keratinocytes

Background

Quercus acuta Thunb. (Fagaceae) or Japanese evergreen oak is cultivated as an ornamental plant in South Korea, China, Japan, and Taiwan and used in traditional medicine. The acorn or fruit of Quercus acuta Thunb. (QAF) is the main ingredient of acorn jelly, a traditional food in Korea. Its leaf was recently shown to have potent xanthine oxidase inhibitory and anti-hyperuricemic activities; however, there have been no studies on the biological activity of QAF extracts. Solar ultraviolet light triggers photoaging of the skin, which increases the production of reactive oxygen species (ROS) and expression of matrix metalloproteinase (MMPs), and destroys collagen fibers, consequently inducing wrinkle formation. The aim of this study was to investigate the effect of water extracts of QAF against UVB-induced skin photoaging and to elucidate the underlying molecular mechanisms in human keratinocytes (HaCaT).

Methods

In this study, we used HPLC to identify the major active components of QAF water extracts. Anti-photoaging effects of QAF extracts were evaluated by analyzing ROS procollagen type I in UVB-irradiated HaCaT keratinocytes. Antiradical activity was determined using 2,2-diphenyl-1-picrylhydrazyl and 2,20-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) assays. The expression of MMP-1 was tested by western blotting and ELISA kits. QAF effects on phosphorylation of the MAPK (p38, JNK, and ERK) pathway and transcription factor AP-1, which enhances the expression of MMPs, were analyzed by western blots.

Results

We identified two major active components in QAF water extracts, gallotannic acid and ellagic acid. The QAF aqueous extracts recovered UVB-induced cell toxicity and reduced oxidative stress by inhibiting intracellular ROS generation in HaCaT cells. QAF rescued UVB-induced collagen degradation by suppressing MMP-1 expression. The anti-photoaging activities of QAF were associated with the inhibition of UVB-induced phosphorylation of extracellular signal-regulated kinase (ERK) and activator protein 1 (AP-1). Our findings indicated that QAF prevents UVB-induced skin damage due to collagen degradation and MMP-1 activation via inactivation of the ERK/AP-1 signaling pathway. Overall, this study strongly suggests that QAF exerts anti-skin-aging effects and is a potential natural biomaterial that inhibits UVB-induced photoaging.

Conclusion

These results show that QAF water extract effectively prevents skin photoaging by enhancing collagen deposition and inhibiting MMP-1 via the ERK/AP-1 signaling pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03473-1.

Advances in Modified Hyaluronic Acid-Based Hydrogels for Skin Wound Healing

Hyaluronic acid (HA) is a natural linear anionic polysaccharide with many unique characteristics such as excellent biocompatibility and biodegradability, native biofunctionality, hydrophilicity, and non-immunoreactivity. HA plays crucial roles in numerous...

NR2F2 controls malignant squamous cell carcinoma state by promoting stemness and invasion and repressing differentiation

The nongenetic mechanisms required to sustain malignant tumor state are poorly understood. During the transition from benign tumors to malignant carcinoma, tumor cells need to repress differentiation and acquire invasive features. Using transcriptional profiling of cancer stem cells from benign tumors and malignant skin squamous cell carcinoma (SCC), we identified the nuclear receptor NR2F2 as uniquely expressed in malignant SCC. Using genetic gain of function and loss of function in vivo, we show that NR2F2 is essential for promoting the malignant tumor state by controlling tumor stemness and maintenance in mouse and human SCC. We demonstrate that NR2F2 promotes tumor cell proliferation, epithelial-mesenchymal transition and invasive features, while repressing tumor differentiation and immune cell infiltration by regulating a common transcriptional program in mouse and human SCCs. Altogether, we identify NR2F2 as a key regulator of malignant cancer stem cell functions that promotes tumor renewal and restricts differentiation to sustain a malignant tumor state.

Role of collagen degradation pathway in sphingomyelin synthase 2-deficient mouse skin

Background

Sphingomyelin synthase (SMS) is the only enzyme that synthesizes sphingomyelin from ceramide. The role of sphingomyelin synthase in epidermis is being understood, but there is no report on its role in the dermis. Quantitative and qualitative evaluation of collagen in SMS2-deficient mice reveals the role of SMS2 in collagen production.

Methods

SMS2-deficient mice were used for in this study. The dermis thickness was measured by Elastica van Gieson staining, the collagen fiber was observed by Scanning Electron Microscopy, the collagen content by ELISA, the ceramide and sphingomyelin content by Thin Layer Chromatography, the collagen-generating and metabolizing gene expression level by RT-PCR, and MMP13 protein level was measured by western blotting.

Results

Thinner dermis in these mice compared to wild-type mice. A reduced number of collagen fibers were observed, and decreased levels of type I collagen and sphingolipids. Gene expression levels of collagen production-related genes in the dermis were found to be unaltered. The expression of several genes related to collagen degradation was found to be affected. The expression level of TNFα and MMP13 and MMP13 protein levels were increased relative to those of wild-type mice, while the expression level of TIMP1 was decreased.

Conclusions

These results indicate that SMS is involved not only in maintaining the sphingolipid content of the epidermal barrier but also in maintaining collagen homeostasis. Further elucidation of the role of SMS2 in the skin may lead to SMS2 comprising a new target for the treatment of skin diseases and the development of functional cosmetics.

Oral Administration of Rosa gallica Prevents UVB-Induced Skin Aging through Targeting the c-Raf Signaling Axis

Rosa gallica is a widely used Rosa species for medicinal and culinary purposes. Rosa gallica has been reported to display antioxidant, anti−inflammatory, and antibacterial activities. However, the effect of Rosa gallica against skin aging in vivo is unknown and its active components have not been fully understood. Oral administration of Rosa gallica prevented UVB−mediated skin wrinkle formation and loss of collagen/keratin fibers in the dorsal skin of mice. Examination of biomarkers at the molecular level showed that Rosa gallica downregulates UVB−induced COX−2 and MMP−1 expression in the skin. Through a direct comparison of major compounds identified using the UHPLC−MS/MS system, we discovered gallic acid as the primary component contributing to the anti-skin aging effect exhibited by Rosa gallica. Examination of the molecular mechanism revealed that gallic acid can potently and selectively target the c−Raf/MEK/ERK/c−Fos signaling axis. In addition, both gallic acid and MEK inhibitor blocked UVB−induced MMP−1 expression and restored collagen levels in a reconstructed 3D human skin model. Collectively, Rosa gallica could be used as a functional ingredient in the development of nutraceuticals against skin aging.

Establishment, maintenance, and recall of inflammatory memory

Known for nearly a century but through mechanisms that remain elusive, cells retain a memory of inflammation that equips them to react quickly and broadly to diverse secondary stimuli. Using murine epidermal stem cells as a model, we elucidate how cells establish, maintain, and recall inflammatory memory. Specifically, we landscape and functionally interrogate temporal, dynamic changes to chromatin accessibility, histone modifications, and transcription factor binding that occur during inflammation, post-resolution, and in memory recall following injury. We unearth an essential, unifying role for the general stress-responsive transcription factor FOS, which partners with JUN and cooperates with stimulus-specific STAT3 to establish memory; JUN then remains with other homeostatic factors on memory domains, facilitating rapid FOS re-recruitment and gene re-activation upon diverse secondary challenges. Extending our findings, we offer a comprehensive, potentially universal mechanism behind inflammatory memory and less discriminate recall phenomena with profound implications for tissue fitness in health and disease.

c-FOS drives reversible basal to squamous cell carcinoma transition

While squamous transdifferentiation within subpopulations of adenocarcinomas represents an important drug resistance problem, its underlying mechanism remains poorly understood. Here, using surface markers of resistant basal cell carcinomas (BCCs) and patient single-cell and bulk transcriptomic data, we uncover the dynamic roadmap of basal to squamous cell carcinoma transition (BST). Experimentally induced BST identifies activator protein 1 (AP-1) family members in regulating tumor plasticity, and we show that c-FOS plays a central role in BST by regulating the accessibility of distinct AP-1 regulatory elements. Remarkably, despite prominent changes in cell morphology and BST marker expression, we show using inducible model systems that c-FOS-mediated BST demonstrates reversibility. Blocking EGFR pathway activation after c-FOS induction partially reverts BST in vitro and prevents BST features in both mouse models and human tumors. Thus, by identifying the molecular basis of BST, our work reveals a therapeutic opportunity targeting plasticity as a mechanism of tumor resistance.

On Deep Landscape Exploration of COVID-19 Patients Cells and Severity Markers

COVID-19 is a disease with a spectrum of clinical responses ranging from moderate to critical. To study and control its effects, a large number of researchers are focused on two substantial aims. On the one hand, the discovery of diverse biomarkers to classify and potentially anticipate the disease severity of patients. These biomarkers could serve as a medical criterion to prioritize attention to those patients with higher prone to severe responses. On the other hand, understanding how the immune system orchestrates its responses in this spectrum of disease severities is a fundamental issue required to design new and optimized therapeutic strategies. In this work, using single-cell RNAseq of bronchoalveolar lavage fluid of nine patients with COVID-19 and three healthy controls, we contribute to both aspects. First, we presented computational supervised machine-learning models with high accuracy in classifying the disease severity (moderate and severe) in patients with COVID-19 starting from single-cell data from bronchoalveolar lavage fluid. Second, we identified regulatory mechanisms from the heterogeneous cell populations in the lungs microenvironment that correlated with different clinical responses. Given the results, patients with moderate COVID-19 symptoms showed an activation/inactivation profile for their analyzed cells leading to a sequential and innocuous immune response. In comparison, severe patients might be promoting cytotoxic and pro-inflammatory responses in a systemic fashion involving epithelial and immune cells without the possibility to develop viral clearance and immune memory. Consequently, we present an in-depth landscape analysis of how transcriptional factors and pathways from these heterogeneous populations can regulate their expression to promote or restrain an effective immune response directly linked to the patients prognosis.

The Protective Effect of Adenocaulon himalaicum Edgew. and Its Bioactive Compound Neochlorogenic Acid against UVB-Induced Skin Damage in Human Dermal Fibroblasts and Epidermal Keratinocytes

Skin aging induced by ultraviolet (UV) irradiation increases expression of matrix metalloproteinase-1 (MMP-1) and destroys collagen fibers, as a result accelerating wrinkle formation. Natural products have been received scientific attention as utilized agents against photoaging. The aim of this study was to investigate the protective effect of Adenocaulon himalaicum Edgew. extract (AHE) against ultraviolet B (UVB)-induced skin damage, and to explain the underlying mechanisms in human dermal fibroblasts and epidermal keratinocytes. AHE effectively protects skin photoaging by preventing collagen degradation through MMP-1 inhibition via the MAPK/AP-1 signaling pathway. AHE significantly increased the expression of skin hydration factors, such as filaggrin, involucrin, loricrin, and caspase-14. To find how AHE possesses a direct impact on cellular activities, we identified neochlorogenic acid as a bioactive component of AHE for the first time. Neochlorogenic acid showed the anti-photoaging effect through ameliorating UVB-induced collagen degradation, reinforcing the skin barrier. Like the AHE-regulating mechanism, neochlorogenic acid modulates the MAPK/AP-1 signaling pathway and skin hydration factors. Taken together, these results suggest that AHE and neochlorogenic acid are well-qualified candidate for enhancing the conditions of photoaged skin.

The m6A mRNA demethylase FTO in granulosa cells retards FOS-dependent ovarian aging

Multifunctional N6-methyladenosine (m6A) has been revealed to be an important epigenetic component in various physiological and pathological processes, but its role in female ovarian aging remains unclear. Thus, we demonstrated m6A demethylase FTO downregulation and the ensuing increased m6A in granulosa cells (GCs) of human aged ovaries, while FTO-knockdown GCs showed faster aging-related phenotypes mediated. Using the m6A-RNA-sequence technique (m6A-seq), increased m6A was found in the FOS-mRNA-3'UTR, which is suggested to be an erasing target of FTO that slows the degradation of FOS-mRNA to upregulate FOS expression in GCs, eventually resulting in GC-mediated ovarian aging. FTO acts as a senescence-retarding protein via m6A, and FOS knockdown significantly alleviates the aging of FTO-knockdown GCs. Altogether, the abovementioned results indicate that FTO in GCs retards FOS-dependent ovarian aging, which is a potential diagnostic and therapeutic target against ovarian aging and age-related reproductive diseases.

Intra-Operative Bioprinting of Hard, Soft, and Hard/Soft Composite Tissues for Craniomaxillofacial Reconstruction

Reconstruction of complex craniomaxillofacial (CMF) defects is challenging due to the highly organized layering of multiple tissue types. Such compartmentalization necessitates the precise and effective use of cells and other biologics to recapitulate the native tissue anatomy. In this study, intra-operative bioprinting (IOB) of different CMF tissues, including bone, skin, and composite (hard/soft) tissues, is demonstrated directly on rats in a surgical setting. A novel extrudable osteogenic hard tissue ink is introduced, which induced substantial bone regeneration, with ≈80% bone coverage area of calvarial defects in 6 weeks. Using droplet-based bioprinting, the soft tissue ink accelerated the reconstruction of full-thickness skin defects and facilitated up to 60% wound closure in 6 days. Most importantly, the use of a hybrid IOB approach is unveiled to reconstitute hard/soft composite tissues in a stratified arrangement with controlled spatial bioink deposition conforming the shape of a new composite defect model, which resulted in ≈80% skin wound closure in 10 days and 50% bone coverage area at Week 6. The presented approach will be absolutely unique in the clinical realm of CMF defects and will have a significant impact on translating bioprinting technologies into the clinic in the future.

The Protective Effects of a Combination of an Arginine Silicate Complex and Magnesium Biotinate Against UV-Induced Skin Damage in Rats

The purpose of this study was to observe the effects of a novel combination of inositol-stabilized arginine silicate complex (ASI) and magnesium biotinate (MgB) on the prevention of skin damage after UVB exposure in rats. Forty-nine Sprague-Dawley rats were randomized into one of the following groups: (1) NC, normal control, (2) SC, shaved control, (3) UVB (exposed to UVB radiation), (4) ASI+MgB-L (Low Dose), (5) ASI+MgB-H (High Dose), (6) ASI+MgB-L+MgB cream, (7) ASI+MgB-H+MgB cream. The results showed that ASI+MgB treatment alleviated the macroscopic and histopathological damages in the skin of rats caused by UVB exposure. Skin elasticity evaluation showed a similar trend. ASI+MgB increased serum Mg, Fe, Zn, Cu, Si, biotin, and arginine concentrations and skin hydroxyproline and biotinidase levels while decreasing skin elastase activity (p < 0.05) and malondialdehyde (MDA) concentration (p < 0.001). Moreover, ASI+MgB treatment increased skin levels of biotin-dependent carboxylases (ACC1, ACC2, PC, PCC, MCC) and decreased mammalian target of rapamycin (mTOR) pathways and matrix metalloproteinase protein levels by the regulation of the activator protein 1 (AP-1), and mitogen activated protein kinases (MAPKs) signaling pathways. In addition, ASI+MgB caused lower levels of inflammatory factors, including TNF-α, NFκB, IL-6, IL-8, and COX-2 in the skin samples (p < 0.05). The levels of Bax and caspase-3 were increased, while anti-apoptotic protein Bcl-2 was decreased by UVB exposure, which was reversed by ASI+MgB treatment. These results show that treatment with ASI and MgB protects against skin damage by improving skin appearance, elasticity, inflammation, apoptosis, and overall health.

In Silico Prediction of Transcription Factor Collaborations Underlying Phenotypic Sexual Dimorphism in Zebrafish (Danio rerio)

The transcriptional regulation of gene expression in higher organisms is essential for different cellular and biological processes. These processes are controlled by transcription factors and their combinatorial interplay, which are crucial for complex genetic programs and transcriptional machinery. The regulation of sex-biased gene expression plays a major role in phenotypic sexual dimorphism in many species, causing dimorphic gene expression patterns between two different sexes. The role of transcription factor (TF) in gene regulatory mechanisms so far has not been studied for sex determination and sex-associated colour patterning in zebrafish with respect to phenotypic sexual dimorphism. To address this open biological issue, we applied bioinformatics approaches for identifying the predicted TF pairs based on their binding sites for sex and colour genes in zebrafish. In this study, we identified 25 (e.g., STAT6-GATA4; JUN-GATA4; SOX9-JUN) and 14 (e.g., IRF-STAT6; SOX9-JUN; STAT6-GATA4) potentially cooperating TFs based on their binding patterns in promoter regions for sex determination and colour pattern genes in zebrafish, respectively. The comparison between identified TFs for sex and colour genes revealed several predicted TF pairs (e.g., STAT6-GATA4; JUN-SOX9) are common for both phenotypes, which may play a pivotal role in phenotypic sexual dimorphism in zebrafish.

The Metabolite Profile in Culture Supernatant of Aster yomena Callus and Its Anti-Photoaging Effect in Skin Cells Exposed to UVB

Aster yomena (A. yomena) extract has anti-inflammatory, antioxidant, anti-asthma, and anti-atopic effects. However, the commercial use of A. yomena extract requires a long processing time with specific processing steps (including heat treatment and ethanol precipitation), and there are various environmental problems. We aimed to build a system to produce A. yomena extract by culturing the callus in a bioreactor that can allow rapid process scale-up to test the effect of extract (AYC-CS-E) isolated from culture supernatant of A. yomena callus on photoaging of human keratinocytes (HaCaT) caused by ultraviolet B (UVB) exposure. Through screening analysis based on ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS), 17 major metabolites were tentatively identified from AYC-CS-E for the first time. The suppression of cell proliferation caused by UVB was effectively alleviated in UVB-irradiated HaCaT cells treated with AYC-CS-E. Treatment with AYC-CS-E strongly induced the formation of type I procollagen and the inhibition of elastase in UVB-irradiated HaCaT cells and significantly reduced the expression of matrix metalloproteinase (MMP)-1. In addition, treatment of UVB-irradiated HaCaT cells with AYC-CS-E effectively improved various factors associated with an inflammatory reaction, skin damage recovery, skin moisture retention, and hyper-keratinization caused by photoaging, such as reactive oxygen species (ROS), pro-inflammatory cytokines, transforming growth factor beta (TGF-β), MMP-3, MMP-9, filaggrin, hyaluronic acid synthase 2 (HAS-2), keratin 1 (KRT-1), nuclear factor-kappa B (NF-κB), and nuclear factor erythroid 2-related factor 2 (Nrf2) at the gene and protein levels. These results suggest that AYC-CS-E can be used as a cosmetic ingredient for various skin diseases caused by photoaging, and the current callus culture system can be used commercially to supply cosmetic ingredients.

Sequestosome 1/p62 enhances chronic skin inflammation

BACKGROUND

The molecular control of inflammation and epidermal thickening in skin lesions of patients with atopic dermatitis (AD) is not known. Sequestosome 1/p62 is a multifunctional adapter protein implicated in the control of key regulators of cellular homeostasis, such as proinflammatory and mechanistic target of rapamycin signaling.

OBJECTIVE

We sought to determine whether p62 plays a role in the cutaneous and systemic manifestations of an AD-like mouse model.

METHODS

AD-like skin lesions were induced by deletion of JunB/AP-1, specifically in epidermal keratinocytes (JunB^Δep). The contribution of p62 to pathological changes was determined by inactivation of p62 in JunB^Δepp62^-/- double knockout mice.

RESULTS

Expression of p62 was elevated in skin lesions of JunB^Δep mice, resembling upregulation of p62 in AD and psoriasis. When p62 was inactivated, JunB^Δep-associated defects in the differentiation of keratinocytes, epidermal thickening, skin infiltration by mast cells and neutrophils, and the development of macroscopic skin lesions were significantly reduced. p62 inactivation had little effect on circulating cytokines, but decreased serum IgE. Signaling through mechanistic target of rapamycin and natural factor kappa B was increased in JunB^Δep but not in JunB^Δepp62^-/- double knockout skin, indicating an important role of p62 in enhancing these signaling pathways in the skin during AD-like inflammation.

CONCLUSIONS

Our results provide the first in vivo evidence for a proinflammatory role of p62 in skin and suggest that p62-dependent signaling pathways may be promising therapeutic targets to ameliorate the skin manifestations of AD and possibly psoriasis.

A Concise Review on the Role of Endoplasmic Reticulum Stress in the Development of Autoimmunity in Vitiligo Pathogenesis

Vitiligo is characterized by circumscribed depigmented macules in the skin resulting due to the autoimmune destruction of melanocytes from the epidermis. Both humoral as well as cell-mediated autoimmune responses are involved in melanocyte destruction. Several studies including ours have established that oxidative stress is involved in vitiligo onset, while autoimmunity contributes to the disease progression. However, the underlying mechanism involved in programing the onset and progression of the disease remains a conundrum. Based on several direct and indirect evidences, we suggested that endoplasmic reticulum (ER) stress might act as a connecting link between oxidative stress and autoimmunity in vitiligo pathogenesis. Oxidative stress disrupts cellular redox potential that extends to the ER causing the accumulation of misfolded proteins, which activates the unfolded protein response (UPR). The primary aim of UPR is to resolve the stress and restore cellular homeostasis for cell survival. Growing evidences suggest a vital role of UPR in immune regulation. Moreover, defective UPR has been implicated in the development of autoimmunity in several autoimmune disorders. ER stress-activated UPR plays an essential role in the regulation and maintenance of innate as well as adaptive immunity, and a defective UPR may result in systemic/tissue level/organ-specific autoimmunity. This review emphasizes on understanding the role of ER stress-induced UPR in the development of systemic and tissue level autoimmunity in vitiligo pathogenesis and its therapeutics.

The role of HOPX in normal tissues and tumor progression

The homeodomain-only protein homeobox (HOPX) as the smallest homeodomain protein, lacks certain conserved residues required for DNA binding. Through our literature search, we reviewed the current understandings of HOPX in normal tissues and tumor progression. HOPX was initially identified as a critical transcription factor in various normal tissues, which interacted with serum response factor (SRF) or other substance to regulate normal physiological function. However, HOPX is at a low expression or methylation level in tumors. These data indicated that HOPX may play a very important role in regulating differentiation phenotype and tumor suppressive function. We predicted the prognosis of HOPX in tumors from TCGA database and discussed the downstream genes of HOPX. To understand how HOPX is involved in the mechanisms between physical and pathological conditions could lead to novel therapeutic strategies for treatment.

AP-1 and TGFß cooperativity drives non-canonical Hedgehog signaling in resistant basal cell carcinoma

Tumor heterogeneity and lack of knowledge about resistant cell states remain a barrier to targeted cancer therapies. Basal cell carcinomas (BCCs) depend on Hedgehog (Hh)/Gli signaling, but can develop mechanisms of Smoothened (SMO) inhibitor resistance. We previously identified a nuclear myocardin-related transcription factor (nMRTF) resistance pathway that amplifies noncanonical Gli1 activity, but characteristics and drivers of the nMRTF cell state remain unknown. Here, we use single cell RNA-sequencing of patient tumors to identify three prognostic surface markers (LYPD3, TACSTD2, and LY6D) which correlate with nMRTF and resistance to SMO inhibitors. The nMRTF cell state resembles transit-amplifying cells of the hair follicle matrix, with AP-1 and TGFß cooperativity driving nMRTF activation. JNK/AP-1 signaling commissions chromatin accessibility and Smad3 DNA binding leading to a transcriptional program of RhoGEFs that facilitate nMRTF activity. Importantly, small molecule AP-1 inhibitors selectively target LYPD3+/TACSTD2+/LY6D+ nMRTF human BCCs ex vivo, opening an avenue for improving combinatorial therapies.

Identification of potential gene drivers of cutaneous squamous cell carcinoma: Analysis of microarray data

Cutaneous squamous cell carcinoma (cSCC) is a common skin cancer with an increasing incidence. As a pre-cancerous condition, actinic keratosis (AK) has an up to 20% risk of progression to cSCC. This study aims to define the potential genes that associated with genesis and progression of cSCC, thereby further identify critical biomarkers for the prevention, early diagnosis, and effective treatment of cSCC.Two datasets GSE42677 and GSE45216 were downloaded from the GEO. Microarray data analysis was applied to explore the differentially expressed genes (DEGs) between cSCC samples and AK samples. Then functional enrichment analysis, protein-protein interaction (PPI) network, and drug-gene interaction analysis were performed to screen key genes.A total of 711 DEGs, including 238 upregulated genes and 473 downregulated genes, were screened out. DEGs mainly involved in pathways as extracellular matrix (ECM)-receptor interaction, hematopoietic cell lineage, phosphatidylinositol 3-kinase (PI3K-Akt) signaling pathway, and focal adhesion. Candidate genes, including upregulated genes as JUN, filamin A (FLNA), casein kinase 1 delta (CSNK1D), and histone cluster 1 H3 family member f (HIST1H3F), and downregulated genes as androgen receptor (AR), heat shock protein family H member 1 (HSPH1), tropomyosin 1 (TPM1), pyruvate kinase, muscle (PKM), LIM domain and actin binding 1 (LIMA1), and synaptopodin (SYNPO) were screened out. In drug-gene interaction analysis, 13 genes and 44 drugs were identified.This study demonstrates that genes JUN, FLNA, AR, HSPH1, and CSNK1D have the potential to function as targets for diagnosis and treatment of cSCC.

Inhibitory Effects of a Sargassum miyabei Yendo on Cutibacterium acnes-Induced Skin Inflammation

Acne vulgaris is a chronic inflammatory condition of skin sebaceous follicles. To explore its effects on acne vulgaris, we investigated the antibacterial and anti-inflammatory activities of Sargassum miyabei Yendo (a brown alga) ethanolic extract (SMYEE) on Cutibacterium acnes (C. acnes)-stimulated inflammatory responses, both in vivo and in vitro. To induce inflammation in vivo, C. acnes was intradermally injected into the dorsal skin of mice, to which SMYEE was applied. The antimicrobial activity of SMYEE was evaluated by the determination of minimum inhibitory concentrations (MICs). To explore in vitro anti-inflammatory effects, HaCaT cells were stimulated with C. acnes after treatment with SMYEE. The levels of IL-8 and the underlying molecular effects in C. acnes-stimulated HaCaT cells were assessed by enzyme-linked immunosorbent assay, Western blotting, and an electrophoretic mobility shift assay. Mouse skin lesions improved after treatment with SMYEE (50 μg/mouse). Neutrophil infiltration was significantly reduced in SMYEE-treated compared to SMYEE-untreated skin lesions. SMYEE reversed the C. acnes-induced increase in IL-8 levels in HaCaT cells and suppressed dHL-60 cell migration. SMYEE also inhibited C. acnes-induced phosphorylation of the extracellular signal-regulated kinase and inhibited activator protein-1 signaling. SMYEE may be a useful treatment for C. acnes-induced acne vulgaris.

Concentrated growth factor inhibits UVA-induced photoaging in human dermal fibroblasts via the MAPK/AP-1 pathway

Ultraviolet (UV) radiation-induced photoaging is one of the contributors to skin aging. UV light triggers oxidative stress, producing a large number of matrix metalloproteinases (MMPs) and degrading the extracellular matrix in skin cells, thereby causing a series of photoaging symptoms. Concentrated growth factor (CGF) is a leukocyte- and platelet-rich fibrin biomaterial that plays a protective role in the occurrence and development of skin photoaging. In the present study, we investigated the underlying mechanism of CGF in the UVA-induced photoaging of human dermal fibroblasts (HDFs). A primary culture of HDFs was isolated from normal human facial skin. The cells were treated with CGF following UVA radiation. Proliferation of cells was detected using MTT assay, followed by measurement of reactive oxygen species (ROS) using immunofluorescence assay and flow cytometry. The mRNA and protein expression levels of P38, c-Jun, and MMP-1 were detected using real-time polymerase chain reaction and Western blot, respectively. CGF was found to improve cell viability by inhibiting the production of ROS and reducing oxidative damage. In addition, there was lower expression of p38 and c-Jun at the mRNA and protein levels following CGF treatment, thus resulting in the inhibition of MMP-1 expression. Our results suggest that CGF could protect HDFs against UVA-induced photoaging by blocking the P38 mitogen-activated protein kinase/activated protein-1 (P38MAPK/AP-1) signaling pathway. These findings provide a new clinical strategy for the prevention of skin photoaging.

Inonotus obliquus Extracts Decreased Expression of MMP1 mRNA via JNK-AP-1 Axis

Inonotus obliquus, which is parasitic on birch and other trees, is a fungus in the family Hymenochaetaceae. In this study, we investigated whether Inonotus obliquus extracts used in traditional medicine were decreased in the expression of matrix metalloproteinases-1 (MMP-1) in the normal human dermal fibroblasts. As shown in our results, extracts of Inonotus obliquus decreased MMP1 expression in oxidative stress-exposed normal human dermal fibroblasts. Additionally, Inonotus obliquus extracts decreased AP-1 transcriptional activity and phospho-JNK in oxidative stress-exposed normal human dermal fibroblasts. Oxidative stress mediated the elevation of MMP1 mRNA expression and was well regulated by the JNK-AP-1 axis. Therefore, the results suggest that Inonotus obliquus extracts decreased MMP1 mRNA expression by regulating JNK-AP-1 axis. Additionally, Inonotus obliquus extracts have the potential to reduce collagen destruction and the formation of wrinkles and to be used as a cosmetic ingredient.

Abnormal neovascular and proliferative conjunctival phenotype in limbal stem cell deficiency is associated with altered microRNA and gene expression modulated by PAX6 mutational status in congenital aniridia

PURPOSE

To evaluate conjunctival cell microRNA (miRNAs) and mRNA expression in relation to observed phenotype of progressive limbal stem cell deficiency in a cohort of subjects with congenital aniridia with known genetic status.

METHODS

Using impression cytology, bulbar conjunctival cells were sampled from 20 subjects with congenital aniridia and 20 age and sex-matched healthy control subjects. RNA was extracted and miRNA and mRNA analyses were performed using microarrays. Results were related to severity of keratopathy and genetic cause of aniridia.

RESULTS

Of 2549 miRNAs, 21 were differentially expressed in aniridia relative to controls (fold change ≤ -1.5 or ≥ +1.5). Among these miR-204-5p, an inhibitor of corneal neovascularization, was downregulated 26.8-fold in severely vascularized corneas. At the mRNA level, 539 transcripts were differentially expressed (fold change ≤ -2 or ≥ +2), among these FOSB and FOS were upregulated 17.5 and 9.7-fold respectively, and JUN by 2.9-fold, all being components of the AP-1 transcription factor complex. Pathway analysis revealed enrichment of PI3K-Akt, MAPK, and Ras signaling pathways in aniridia. For several miRNAs and transcripts regulating retinoic acid metabolism, expression levels correlated with keratopathy severity and genetic status.

CONCLUSION

Strong dysregulation of key factors at the miRNA and mRNA level suggests that the conjunctiva in aniridia is abnormally maintained in a pro-angiogenic and proliferative state, and these changes are expressed in a PAX6 mutation-dependent manner. Additionally, retinoic acid metabolism is disrupted in severe, but not mild forms of the limbal stem cell deficiency in aniridia.

Antiphotoaging Effects of 3,5-Dicaffeoyl-epi-quinic Acid via Inhibition of Matrix Metalloproteinases in UVB-Irradiated Human Keratinocytes

UVB exposure is one of the causes of several skin complications including but not limited to premature aging, wrinkle formation, and hyperpigmentation. UV-induced skin aging is called photoaging, and oxidative stress-induced overexpression of matrix metalloproteinases (MMPs) is the main reason behind the photoaging-mediated collagen degradation. Natural origin inhibitors of MMPs are regarded as a promising approach to prevent or treat photoaging. Therefore, the present study investigated the protective effects of 3,5-dicaffeoyl-epi-quinic acid (DCEQA) in human HaCaT keratinocytes against UVB irradiation-related dysregulation of MMPs. Changes in the mRNA and protein expression and release of MMP-1, -2, and -9 were observed after UVB irradiation with or without DCEQA treatment. In addition, the effect of DCEQA on the activation of p38, JNK, and ERK MAPKs was analyzed. Treatment of UVB-irradiated HaCaT cells with 10 μM DCEQA significantly suppressed the overexpression of both mRNA and protein of MMP-1, -2, and -9 while slightly increasing the diminished type I procollagen production. UVB-induced activation of MAPKs was also ameliorated by DCEQA treatment in a dose-dependent manner. Results indicated that DCEQA treatment was able to protect keratinocytes from UVB-induced photoaging by inhibiting the stimulated production of MMPs and the related decrease in collagen production. It was suggested that DCEQA downregulated the collagen degradation via inhibition of MAPK activation, which resulted in decreased MMP activity.