Tight Junction Proteins Claudin-1 and Occludin Are Important for Cutaneous Wound Healing

Decoding the pharmacodynamics of Fufang Tongye Shaoshang You: A promising ethnomedicine for diabetic ulcer healing

ETHNOPHARMACOLOGICAL RELEVANCE

Fufang Tongye Shaoshang You (TYY) is an ethnomedicine derived from the traditional folk formula of the Tujia people in Hunan Province, which consists of Paulownia leaf and sesame oil, has shown promising potential in promoting diabetic ulcer (DU) healing. However, its pharmacological substance and mechanism of action require further elucidation.

AIMS OF THE STUDY

This study was designed to assess the healing effect of TYY on DU wounds in mice, and to explore systematically its potential mechanisms and pharmacodynamic material basis.

METHODS

The combination of high-fat, high-sugar diet and streptozotocin injection was used to induce C57BL/6 J mouse diabetic model, and the ulcer was surgically introduced. After TYY treatment, the skin lesions of diabetic mice were observed by H&E, Masson staining and transmission electron microscopy over a period of time. The wound tissues were collected. Transcriptomics were used to predict the potential mechanism of TYY, and then immunohistochemistry, immunofluorescence, ELISA, Western blotting, and qRT-PCR were used to detect the expression levels of key proteins and mRNA in related signaling pathways. The effect of TYY on tight junction proteins was evaluated by Western blotting. The chemical components of 10 batches of TYY were analyzed by multivariate analysis, and the iconic components of TYY were screened by molecular docking and dynamics simulation. HMEC-1 cells were induced by lipopolysaccharide and high glucose concentrations to simulate a DU microenvironment and construct an endothelial cell injury model. Scratch test and RT-qPCR were used to evaluate the effects of TYY active ingredients on the endothelial cell injury model, finally determining the pharmacodynamic material basis of TYY.

RESULTS

The study has demonstrated that TYY can not only effectively repair the skin barrier, but also regulate the IL-17-mediated NF-κB/AP-1 signaling pathway, inhibit the exacerbation of inflammation, and accelerate wound healing in DU mice. In addition, we further discovered the key active ingredients of TYY: maslinic acid, corosolic acid, oleanolic acid, ursolic acid and sesamin.

CONCLUSION

This study provides scientific evidence for TYY as a potential drug to repair DU, and also provides a theoretical basis for its further clinical application and drug development.

Complete omission of exon 21 from Slc12a2 transcripts in mice results in hearing loss

Hereditary hearing loss is highly heterogeneous. SLC12A2 is linked to autosomal dominant nonsyndromic hearing loss, DFNA78, with all the pathogenic variants affecting the exon 21. The gene encodes a cotransporter NKCC1 crucial for regulating intracellular osmotic pressure and producing endolymph in the cochlea. We generated two mouse strains with heterologous Slc12a2 variants in the splice site of the exon 21 (Em1: NM_009194.3:c.2912-2 A > G and Em2: c.2912-4_2913del). Slc12a2Em2/Em2 mice with complete skip of the exon 21 showed reduced endolymph on postnatal day 1 (P1), reduced stria vascularis (StV) and no auditory brainstem responses at 4 weeks. Reduced StV size was considered to be due to rebalance osmotic pressure, and upregulation of Cldn9 revealed by RNA-seq was considered as tissue response to repair the gaps from reduced cell sizes in the Slc12a2Em2/Em2 cochlea. Female Slc12a2Em2/+ mice also exhibited mild elevation of ABR thresholds in several sound frequencies. Slc12a2Em1/Em1 mice showed normal hearing, presumably due to sufficient cotransporter activity from the 9 bases shorter transcript by cryptic splicing. Minigene assays indicated that a single nucleotide difference between humans and mice at the 5' end of the exon 21 affects exon 21 splicing. Slc12a2Em2 mouse is proposed as a model for studying DFNA78 pathology.

Claudin-1 expression in acne and its correlation with disease severity: clinical and in silico validation

The pilosebaceous unit is the site of a common chronic inflammatory skin disorder called acne. Tight junctions (TJ) are present in sebocytes and are primarily composed of claudin-1. When claudin-1 is knocked down, the TJ barrier leaks, and holocrine secretion is compromised. This leads to the accumulation of partially degenerated sebocytes in the pilosebaceous ducts and the creation of microcomedos, which can cause acne lesions. The study's aim was to measure the claudin-1 gene and protein expression in acne patients' blood samples and establish a correlation with the severity of the condition and their levels. 48 acne patients were involved and 48 matched control for age and sex. First samples were obtained from both groups and RNA was extracted from the whole blood sample followed by qPCR to measure the relative expression of the claudin-1 gene. Enzyme-linked immunosorbent assay (ELISA) was used to measure claudin-1 protein level. There were statistically significant lower relative expression of claudin-1 gene (p = 0.001) and its protein level (p = 0.001) in acne patients compared to controls (0.34 ± 0.32 vs 1.0 ± 0.0, 0.64 ± 0.62 vs 3.85 ± 2.14, respectively). There was a statistically significant inverse correlation between claudin-1 protein expression and acne severity (R = -0.374, p = 0.009). Computational and bioinformatics tools were used for enrichment analysis to better understand claudin-1 role in the context of the disease and provide possible therapeutic approaches. Claudin-1 dysregulation in acne patients, suggest that it have an impact on the severity and course of acne through affecting the epidermal barrier and facilitating inflammation.

PVA and PVP nanofibers combined with Helichrysum italicum oil preserve skin cell interactions, elasticity and proliferation

Development of electrospun nanofibers with suitable properties to promote wound healing is an advantage in developing non-invasive skin treatments. We showed the potential application of Polyvinyl acetate (PVA) and Polyvinylpyrrolidone (PVP) combined with Helichrysum italicum oil (HO) in wound healing. During this process, Tight junctions (TJs) play a crucial role in maintaining skin integrity. TJs are intercellular junctions composed of a variety of transmembrane proteins, including Occludin (OCLN), observed also in migrating epithelial cells. Changes in OCLN expression affect epidermal permeability, indicating an active role in the healing process. Within this context, we studied the OCLN expression during healing after scratch assay on Keratinocytes (HaCaT), by a confocal microscopic analysis. In addition, we evaluated the effect of treatment after scratch on cell elasticity by Atomic Force Microscopy (AFM) analysis. All results show a positive trend in cell proliferation and viability on HaCaT treated with functionalized nanofibers. These results were confirmed by the expression of genes involved in the early stages of the regenerative process. Understanding the cell mechanisms involved in skin changes during repair process would allow future application of nanomaterials combined with HO in vivo.

Prurigo nodularis and the microbiome

Prurigo nodularis (PN) is a chronic skin condition that profoundly impacts quality of life. Histopathological studies of itchy hyperkeratotic nodules show dense infiltrates of T lymphocytes, mast cells, and eosinophils. A robust inflammatory response is implicated, coupled with key changes in neuronal plasticity that affect nerve fiber architecture and function. The microbial community in PN lesions exhibits a distinct composition, marked by decreased α-diversity and a prominent increase in Staphylococcus aureus (S aureus). This alteration appears to contribute to the disease's pathophysiology, causing further disruption of the skin barrier, immune dysregulation, and neuronal plasticity. There is ample evidence that virulence factors of S aureus promote Th2, Th17, and Th22 cytokine production, which are key to PN. In addition, S aureus V8 protease (Endoproteinase Glu-C) has recently been identified to trigger robust itch by activating protease-activated receptor 1 (PAR1) on sensory neurons. This review underscores the complex interplay between the altered microbiome and the itch-scratch cycle of PN, providing insights into potential therapeutics targeting the skin microbiome. A multidisciplinary approach is crucial for providing relief to individuals suffering from this skin condition.

Hydrogel-Transformable Probiotic Powder for Targeted Eradication of Helicobacter pylori with Enhanced Gastric Mucosal Repair and Microbiota Preservation

Lactobacillus reuteri (L. reuteri) therapies represent a potentially effective approach to eradicating Helicobacter pylori (H. pylori). However, the difficulty in bacterial viability preservation and harsh gastric environment compromises the survival and on-target delivery of L. reuteri. This study presents a novel bacterium-mediated bacterial elimination strategy using an edible L. reuteri@HTP probiotic powder for targeted bacterial elimination. The probiotic powder is obtained by grinding a lyophilized hydrogel composed of L. reuteri, hyaluronic acid (HA), tannic acid (TA), and polyvinyl alcohol (PVA). Upon contact with water, the powder quickly transforms into a hydrogel, enhancing L. reuteri's survival in the harsh gastric environment and ensuring selective release at H. pylori-infected inflammatory sites. L. reuteri targets and reduces H. pylori colonization while secreting reuterin to eliminate the bacteria. Additionally, TA's antioxidant properties help alleviate inflammation, and HA supports gastric mucosal repair. L. reuteri@HTP powder preserves the integrity of the gut microbiota, facilitating the restoration of a healthy microbiome. In particular, the probiotic powder remains stable at room temperature for at least six months, providing a promising alternative to traditional antibiotics for H. pylori treatment. This strategy combines targeted eradication, mucosal healing, and microbiome restoration, offering a new approach to treating gastric infections.

The cyclization of human salivary Histatin 1 via click chemistry for skin wound healing

Acute skin injuries can result in the breakdown of the skin barrier, heightening the risk of infections and complications. Histatin 1 (Hst1) promotes the adhesion, spreading, and migration of various skin-related cells, thus encouraging wound healing. However, Hst1 is extensively degraded upon exposure to wound exudates. Cyclized hst1 (Cyclic-hst1) has a much higher resistance to protease degradation than Hst1, thus increasing its stability and half-life. Herein, we synthesized Cyclic-hst1 via a click reaction and explored its efficacy in wound healing via cellular and animal experiments. Cyclic-hst1, at a 100-fold lower concentration than Hst1, effectively promoted acute skin wound healing. In addition, Cyclic-hst1 had a superior effect to Hst1 in terms of its anti-inflammatory, re-epithelialization, collagen deposition, and angiogenic effects, thus significantly promoting skin wound healing. Consequently, Cyclic-hst1 could represent a favorable treatment to manage acute skin wound healing, providing a promising experimental basis for clinical transformation and application.

Hyaluronic Acid/Gelatin-Based Multifunctional Bioadhesive Hydrogel Loaded with a Broad-Spectrum Bacteriocin for Enhancing Diabetic Wound Healing

The development of multifunctional wound adhesives is critical in clinical settings due to the scarcity of dressings with effective adhesive properties while protecting against infection by drug-resistant bacteria. Polysaccharide and gelatin-based hydrogels, known for their biocompatibility and bioactivity, assist in wound healing. This study introduces a multifunctional bioadhesive hydrogel developed through dynamic covalent bonding and light-triggered covalent bonding, comprising oxidized hyaluronic acid, methacrylated gelatin, and the bacteriocin recently discovered by our lab, named jileicin (JC). The adhesion strength of the hydrogel, measured at 180 kPa, was 4.35 times higher than that of the fibrin glue. Furthermore, the hydrogel demonstrated robust platelet adhesion, procoagulant activity, and outstanding hemostatic properties in a mouse liver injury model. Incorporating JC significantly enhanced the phagocytosis and bactericidal capabilities of the macrophages. This immunomodulatory function on host cells, coupled with its potent bacterial membrane-disrupting ability, makes JC an effective killer against methicillin-resistant Staphylococcus aureus. In wound repair experiments on diabetic mice with infected full-thickness skin defects, the hydrogel treatment group showed a notable reduction in bacterial load, accelerated M2-type macrophage polarization, diminished inflammation, and hastened wound healing. Owing to its outstanding biocompatibility, antibacterial activity, and controlled adhesion, this hydrogel presents a promising therapeutic option for treating infected skin wounds.

Upregulation of SEMP1 Contributes to Improving the Biological Functions of Trophoblast via the PI3K/AKT Pathway in Preeclampsia

Disturbance of extravillous trophoblast infiltration is associated with preeclampsia (PE), a severe condition of pregnancy characterized by hypertension and proteinuria. Senescence-associated epithelial membrane protein 1 (SEMP1), an integral membrane protein, is a vital component of tight junction strands in epithelial or endothelial cells, with no clear function reported in PE. Gene Expression Omnibus (GEO) datasets showed that SEMP1 expression was downregulated in the placental tissues of PE patients, which was confirmed by assessing SEMP1 levels in placental samples collected in our hospital. Furthermore, less SEMP1 was detected in cytokeratin 7 positive trophoblast cells in the spiral arteries of rat placentas post L-arginine methyl ester hydrochloride (L-NAME) treatment. Trophoblast cells acquired robust ability of proliferation, migration, and invasion when SEMP1 was overexpressed. Such capability was weakened in SEMP1-silenced cells. Trophoblast cells overexpressing SEMP1 secreted more vascular endothelial growth factor A (VEGFA), which facilitated the tube formation of human umbilical vein endothelial cells. Blockade of PI3K/AKT signaling transduction with LY294002 dampened the effects of SEMP1 on trophoblast cells. Collectively, we firstly indicated that SEMP1 inhibition is a potential driver for PE, which may be associated with the deactivation of the PI3K/AKT pathway.

The potential cutaneous benefits of edible bird's nest

Edible bird's nest (EBN) is composed of the solidified saliva of swiftlet birds. EBN has been extremely popular in Asian culture for centuries. They are often consumed as a delicacy in the form of bird's nest soup and are believed to have numerous skin benefits. In light of EBN's growing popularity and significant cultural importance, we aim provide a comprehensive review of EBN's potential dermatologic benefits and role in photoaging, anti-inflammation, wound healing, skin barrier enhancement, and skin whitening. While in vitro, in vivo, and preliminary clinical trial results are promising, there is a need for future human clinical research to further validate these findings and establish EBN's efficacy and safety for dermatologic applications.

Lespedeza maximowiczii flower absolute promotes skin epithelization, barrier properties, and moisturization-related beneficial responses in human keratinocytes

Lespedeza maximowiczii (LM), a member of the legume family, has tyrosinase inhibitory and estrogenic activities. However, its effects on skin-related biological activities remain unclear. Therefore, the present study aimed to explore the effects of LM flower absolute (LMFAb) on skin-related biological events, especially skin re-epithelization, barrier and moisturizing-related keratinocyte (HaCaT cell) responses. In this study, LMFAb was isolated from LM flowers via solvent extraction and its chemical composition analysis was performed using gas chromatography/mass spectrometry. 5-bromo-2'-deoxyuridine incorporation, Boyden chamber, sprout outgrowth, enzyme-linked immunosorbent, and Western blot assay were used to analyze the biological effects of LMFAb on HaCaT cells (a human epidermal keratinocyte cell line). Twelve components were identified in LMFAb. LMFAb promoted cell proliferation, migration, and sprout outgrowth in HaCaT cells. The absolute enhanced the activations of MAPKs (ERK1/2, JNK, and p38), PI3K and AKT proteins in HaCaT cells and elevated collagen type I and IV levels in HaCaT cell conditioned medium. In addition, LMFAb induced an increase in the expression levels of epidermal barrier proteins (filaggrin and involucrin) in HaCaT cells. Furthermore, LMFAb increased hyaluronan (HA) production and expression of HA synthases (HAS-1, HAS-2, and HAS-3) but decreased HYBID (HA binding protein involved in HA depolymerization) level in HaCaT cells. These findings demonstrate that LMFAb might promote skin re-epithelization, barrier and moisturizing-related beneficial responses in keratinocytes. This study suggests that LMFAb should be considered a potential starting material for the development of cosmetic or pharmaceutical agents that restore the functions of damaged skin.

Low-Dose Trypsin Accelerates Wound Healing via Protease-Activated Receptor 2

The management of wounds remains a significant healthcare challenge, highlighting the need for effective wound healing strategies. To address this, it is crucial to explore the molecular mechanisms underlying tissue repair as well as explore potential therapeutic approaches. Trypsin, as a serine protease, has been clinically utilized for wound healing for decades; however, it still lacks systemic investigation on its role and related mechanism. This study aimed to investigate the effects of low-dose trypsin on wound healing both in vitro and in vivo. While trypsin is an endogenous stimulus for protease-activated receptor 2 (PAR2), we discovered that both low-dose trypsin and synthesized PAR2 agonists significantly enhanced the migration, adhesion, and proliferation of fibroblasts and macrophages, similar to the natural repair mechanism mediated by mast cell tryptase. Moreover, such cell functions induced by trypsin were largely inhibited by PAR2 blockade, indicating the participation of trypsin via PAR2 activation. Additionally, low-dose trypsin notably expedited healing and regeneration while enhancing collagen deposition in skin wounds in vivo. Importantly, upon stimulation of trypsin or PAR2 agonists, there were significant upregulations of genes including claudin-7 (Cldn7), occludin (Ocln), and interleukin-17A (IL-17A) associated with proliferation and migration, extracellular matrix (ECM), tight junction, and focal adhesion, which contributed to wound healing. In summary, our study suggested that a low-dose trypsin could be a promising strategy for wound healing, and its function was highly dependent on PAR2 activation.

Drug monomers from Salvia miltiorrhiza Bge. promoting tight junction protein expression for therapeutic effects on lung cancer

Salvia miltiorrhiza Bge. is a traditional Chinese medicine (TCM) that has been used for treatment of various diseases, including cancer by activating blood circulation and removing blood stasis. Tanshinone (TanIIA) and cryptotanshinone (CPT) are major lipophilic compounds extracted from the root of Salvia miltiorrhiza Bge., which are considered to be the effective compounds affecting the efficacy of the anti-tumor therapy of Salvia miltiorrhiza Bge. We have explored the mechanism of CPT and TanIIA exerting inhibition in non-small cell lung cancer (NSCLC) to provide experimental data support for guiding the translational development and clinical application of anti-tumor components of TCM. The subcutaneous tumor model and in vitro culture model of A549 cells was constructed to evaluate CPT and TanIIA's tumour-inhibitory effect respectively. RNA sequencing (RNA-seq) and bioinformatics analysis were conducted to identify differentially expressed genes (DEGs) and signalling pathways related to CPT and TanIIA treatment. qRT-PCR and Western blot were used to explore the mechanism of CPT and TanIIA intervention on NSCLC. Both CPT and TanIIA significantly inhibited the proliferation of A549 tumor cells and tumor growth in animal models. After intervention, the migration ability decreased and the level of apoptosis increased. RNA-seq results showed that both CPT and TanIIA could cause gene differential expression, miR-21-5p as one of the most significant gene expression differences between the two groups, and could act on cell connectivity. CPT and TanIIA play a regulatory role in regulating tight junction proteins (Occludin and ZO1), and Occludin mRNA and protein levels were reduced in an in vitro miR-21-5p overexpression A549 cell model. The mechanisms may be related to the reduction of miR-21-5p expression to increase the level of promoted tight junction protein expression for the purpose of inhibiting proliferation and invasion of NSCLC.

Immunomodulatory mechanisms of an acidic polysaccharide from the fermented burdock residue by Rhizopus nigricans in RAW264.7 cells and cyclophosphamide-induced immunosuppressive mice

RBAPS is an acidic polysaccharide extracted from the burdock residue fermentation by Rhizopus nigricans. In RBAPS-activated RAW264.7 cells, transcriptome analysis identified a total of 1520 differentially expressed genes (DEGs), including 1223 down-regulated genes and 297 up-regulated genes. DEGs were enriched in the immune-related biological processes, involving in Mitogen-activated protein kinase (MAPK) and Toll-like receptor (TLR) signaling pathway, according to Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. The results of the confocal laser scanning microscope (CLSM) observation, antibody neutralization and Western blot verified that RBAPS modulated macrophages activation and cytokines secretion mainly via TLR4/MAPK/NF-κB signaling pathway. The immunomodulatory activity in vivo of RBAPS was investigated in cyclophosphamide (CTX)-induced immunosuppressive mice. RBAPS promoted the counts of white blood cells (WBC), red blood cells (RBC) and platelets (PLT) as well as the levels of immunoglobulins and cytokines (IgG, IgM, TNF-α, and IL-2) in immunosuppressive mice. RBAPS protected the spleen and thymus from CTX-induced injury by increasing the organ indexes, attenuating pathological damage, and promoting splenic lymphocytes proliferation. Importantly, RBAPS ameliorated the intestine integrity and function by promoting the expression of Occuldin, Claudin-5, Atg5, and Atg7, activating TLR4/MAPK signaling pathway in CTX-induced mice. This study suggested that RBAPS was a prime candidate of immunologic adjuvant in chemotherapy for the nutraceutical and pharmaceutical application.

Macrocystis pyrifera Lipids Reduce Cytokine-Induced Pro-Inflammatory Signalling and Barrier Dysfunction in Human Keratinocyte Models

Atopic dermatitis is a chronic condition where epidermal barrier dysfunction and cytokine production by infiltrating immune cells exacerbate skin inflammation and damage. A total lipid extract from Macrocystis pyrifera, a brown seaweed, was previously reported to suppress inflammatory responses in monocytes. Here, treatment of human HaCaT keratinocytes with M. pyrifera lipids inhibited tumour necrosis factor (TNF)-α induced TNF receptor-associated factor 2 and monocyte chemoattractant protein (MCP)-1 protein production. HaCaT cells stimulated with TNF-α, interleukin (IL)-4, and IL-13 showed loss of claudin-1 tight junctions, but little improvement was observed following lipid pre-treatment. Three-dimensional cultures of HaCaT cells differentiated at the air-liquid interface showed increased MCP-1 production, loss of claudin-1 tight junctions, and trans-epidermal leakage with TNF-α, IL-4, and IL-13 stimulation, with all parameters reduced by lipid pre-treatment. These findings suggest that M. pyrifera lipids have anti-inflammatory and barrier-protective effects on keratinocytes, which may be beneficial for the treatment of atopic dermatitis or other skin conditions.

Are the Cutaneous Microbiota a Guardian of the Skin's Physical Barrier? The Intricate Relationship between Skin Microbes and Barrier Integrity

The skin is a tightly regulated, balanced interface that maintains our integrity through a complex barrier comprising physical or mechanical, chemical, microbiological, and immunological components. The skin's microbiota affect various properties, one of which is the establishment and maintenance of the physical barrier. This is achieved by influencing multiple processes, including keratinocyte differentiation, stratum corneum formation, and regulation of intercellular contacts. In this review, we summarize the potential contribution of Cutibacterium acnes to these events and outline the contribution of bacterially induced barrier defects to the pathogenesis of acne vulgaris. With the combined effects of a Westernized lifestyle, microbial dysbiosis, epithelial barrier defects, and inflammation, the development of acne is very similar to that of several other multifactorial diseases of barrier organs (e.g., inflammatory bowel disease, celiac disease, asthma, atopic dermatitis, and chronic rhinosinusitis). Therefore, the management of acne requires a complex approach, which should be taken into account when designing novel treatments that address not only the inflammatory and microbial components but also the maintenance and strengthening of the cutaneous physical barrier.

Managing the Skin Microbiome as a New Bacteriotherapy for Inflammatory Atopic Dermatitis

The microbiome, comprising various bacteria, assumes a significant role in the immune system's maturation and maintaining bodily homeostasis. Alterations in the microbial composition can contribute to the initiation and progression of inflammation. Recent studies reveal that changes in microbial composition and function, known as dysbiosis in the skin and gut, have been associated with altered immunological responses and skin barrier disruption. These changes are implicated in the development of several skin diseases, such as atopic dermatitis (AD). This review examines research demonstrating the potential of microbiome repair as a therapeutic approach to reduce the effect of inflammatory processes in the skin during atopic dermatitis. This way, corticosteroids in atopic dermatitis therapy can be reduced or even replaced with treatments focusing on controlling the skin microbiome. This study used scientific literature from recognized platforms, including PubMed, Scopus, Google Scholar, and ScienceDirect, covering publications from 2013 to 2023. The primary aim of this study was to assess the efficacy of skin microbiome management in treating atopic dermatitis. This study concludes that physicians must comprehensively understand the microbiome's involvement in atopic dermatitis, including its pathophysiological implications and its relevance to therapeutic interventions.

Role of syntaxin3 an apical polarity protein in poorly polarized keratinocytes: regulation of asymmetric barrier formations in the skin epidermis

The skin epidermis exhibits an asymmetric structure composed of multilayered keratinocytes and those in the outer layers form two-way physical barriers, cornified cell envelope (CCE), and tight junctions (TJs). While undifferentiated keratinocytes in the basal layer continuously deliver daughter cells outward, which undergo successive differentiation with losing their polarized characteristics, they retain the expression of several polarity proteins. In the present study, we revealed that the t-SNARE protein syntaxin3, a critical element for the formation of the apical compartment in simple epithelial cells, is required to confer the ability to organize the physical barriers on "poorly polarized" keratinocytes in epidermal outer layers. HaCaT keratinocytes with genetic ablation of syntaxin3 readily succumbed to hydrogen peroxide-induced cell death. Additionally, they lost the ability to organize TJ and CCE structures, accompanied by notable downregulation of transglutaminase1 and caspase14 (a cornification regulator) expression. These syntaxin3-knockout cells appeared to restore oxidative stress tolerance and functional TJ formation ability, in response to the inducible re-expression of exogenous syntaxin3. While plausible mechanisms underlying these phenomena remain unclear, syntaxin3, an apical polarity protein in the simple epithelia, has emerged as a potentially crucial element for barrier formation in poorly polarized keratinocytes in polarized epidermal tissue.

E-cadherin and aquaporin-3 are downregulated in wound edges of human chronic wounds

Chronic wounds are defined as wounds that fail to proceed through the normal phases of wound healing; a complex process involving different dynamic events including migration of keratinocytes in the epidermis. Chronic wounds are estimated to affect 1-2% of the human population worldwide and are a major socioeconomic burden. The prevalence of chronic wounds is expected to increase with the rising number of elderly and patients with diabetes and obesity, who are at high risk of developing chronic wounds. Since E-cadherin and the water channel aquaporin-3 are important for both skin function and cell migration, and aquaporin-3 is furthermore involved in wound healing of the skin demonstrated by impaired wound healing in aquaporin-3-null mice, we hypothesized that E-cadherin and aquaporin-3 expression may be dysregulated in chronic wounds. Therefore, we investigated the expression of E-cadherin and aquaporin-3 in biopsies from the edges of chronic wounds from human patients. This was accomplished by immunohistochemical stainings of E-cadherin and aquaporin-3 on serial sections followed by qualitative evaluation of staining patterns, which revealed low expression of both E-cadherin and aquaporin-3 at the wound edge. Future studies are needed to reveal if this downregulation is associated with the pathophysiology of chronic wounds.

Osthole relieves skin damage and inhibits chronic itch through modulation of Akt/ZO-3 pathway in atopic dermatitis

Atopic dermatitis (AD) is the most prevalent chronic inflammatory skin condition and significantly reduces quality of life. Tight junction (TJ), which is located directly beneath the stratum corneum, maintains skin barrier function and aids in the identification of the cell's "territory". We evaluated seventeen TJ related genes to explore AD related alterations of TJ. Remarkably, we found that the expression of ZO-3, a gene that had not been linked to the development of TJ in AD, was significantly down-regulated in the skin of AD mice and patients. siRNA mediated knock-down of ZO-3 significantly decreased transepithelial electrical resistance in HaCaT cells, demonstrating that ZO-3 is essential to epidermal barrier function. In addition to ZO-3 downregulation, protein kinase B (Akt) phosphorylation was increased in the skin of AD mice. We further confirmed an inverse relationship between Akt phosphorylation and ZO-3 expression in AD using HaCaT cells and mouse model. Finally, we tested the efficacy of osthole as a treatment for AD in mice and HaCaT cells. Osthole inhibits Akt phosphorylation, and thereby enhances ZO-3 expression in mouse models of AD, resulting in greatly lessened AD associated skin damage and chronic itch, and osthole also increased the expression of ZO-3 in HaCaT cells by inhibiting the phosphorylation of Akt. Together, we established that ZO-3 is essential for the development of TJ in AD skin and HaCaT cells, and our findings provide fresh support for osthole's ability to protect ZO-3 expression and the epidermal barrier in AD.

Protective effect of Paecilomyces cicadae TJJ11213 exopolysaccharide on intestinal mucosa and regulation of gut microbiota in immunosuppressed mice

The exopolysaccharide (EPS) form Paecilomyces cicadae TJJ1213 possessed immunomodulatory activity in vitro, but whether it could regulate the immune system and intestinal microbiota in vivo remained unknown. In this study, the cyclophosphamide (CTX)-induced immunosuppressive mouse model was established to explore the immunomodulatory activity of EPS. Results showed that EPS could increase the immune organ indices, promote the secretion of serum immunoglobulins and up-regulate the expression of cytokines. Additionally, EPS could repair CTX-induced intestinal injury by increasing the expression of tight junction proteins and promoting the production of short-chain fatty acids. Moreover, EPS could remarkably enhance immunity through TLR4/MyD88/NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways. Furthermore, EPS regulated intestinal microbiota by increasing the abundance of beneficial bacteria (Muribaculaceae, Lachnospiraceae NK4A136, Bacteroides, Odoribacter) and reducing the level of harmful bacteria (Alistipes, Helicobacter). In conclusion, our study suggested that EPS had the abilities to enhance immunity, restore intestinal mucosal injury and modulate intestinal microbiota, and may serve as a potential prebiotic to maintain health in the future.

Molecular weight-dependent hyaluronic acid permeability and tight junction modulation in human buccal TR146 cell monolayers

The oral route is considered an attractive method for drug delivery, as it avoids the hepatic and intestinal first-pass metabolism processes. Hyaluronic acid (HA) beneficial effects to the human body include anti-aging and wound healing but its effects on oral barrier integrity and mechanical function have not yet been investigated. In this study, we analyzed oral barrier integrity and the paracellular pathway of HA transportation in TR146 cell monolayers during and after permeation and using low molecular weight HA (LMW-HA, <100 kDa) and high molecular weight HA (HMW-HA, >500 kDa). Cytotoxicity assays in TR146 cells revealed that neither LMW-HA or HMW-HA altered cell viability at concentrations <0.5 % during 24 h of treatment. HA-treated TR146 cell monolayers showed enhanced oral barrier integrity and reduced apparent permeability of fluorescein. Moreover, HA significantly increased tight junction (TJ)-related genes expression, including ZO-2, marvelD3, cingulin, claudin-1, claudin-3, and claudin-4 expression. Overall, the results of the present study indicate that HA can permeate across the oral barrier and enhance oral barrier function via the upregulated expression of TJ-related genes.

Algal oil alleviates antibiotic-induced intestinal inflammation by regulating gut microbiota and repairing intestinal barrier

Introduction

Taking antibiotics would interfere with gut microbiota and increase the risk of opportunistic pathogen infection and inflammation.

Methods

In this study, 36 male C57BL/6 mice were divided into 4 groups (n = 9) to investigate whether two kinds of algal oil could alleviate the intestinal damage induced by CS (Ceftriaxone sodium). These algal oils were obtained from Schizochytrium sp. cultures using Yeast extract (YE) and Rapeseed meal (RSM) as substrate, respectively. All tested mice were administrated with CS for 8 days and then the colon pathological morphology, the expression levels of inflammatory factors and the gut microbial profile were analyzed in mice supplemented with or without algal oil.

Results

The results showed that both YE and RSM algal oils markedly reduced mucosal damage and intestinal inflammatory response in CS-treated mice by inhibiting the pro-inflammatory cytokine tumor necrosis factor (TNF)-α, interleukin (IL)-6 and myeloperoxidase (MPO) activity. In addition, fluorescence immunohistochemistry showed that the tight junction protein ZO-1 was increased in mice supplemented with YE and RSM algal oil. Furthermore, YE algal oil promoted the beneficial intestinal bacteria such as Lachnospiraceae and S24_7 compared with the CS group, while supplementation with RSM algal oil enriched the Robinsoniella. Spearman's correlation analysis exhibited that Melissococcus and Parabacteroides were positively correlated with IL-6 but negatively correlated with IL-10.

Discussion

This study suggested that supplementation with algal oil could alleviate intestinal inflammation by regulating gut microbiota and had a protective effect on maintaining intestinal barrier against antibiotic-induced damage in mice.

Skin Barrier Function and the Microbiome

Human skin is the largest organ and serves as the first line of defense against environmental factors. The human microbiota is defined as the total microbial community that coexists in the human body, while the microbiome refers to the collective genome of these microorganisms. Skin microbes do not simply reside on the skin but interact with the skin in a variety of ways, significantly affecting the skin barrier function. Here, we discuss recent insights into the symbiotic relationships between the microbiome and the skin barrier in physical, chemical, and innate/adaptive immunological ways. We discuss the gut-skin axis that affects skin barrier function. Finally, we examine the effects of microbiome dysbiosis on skin barrier function and the role of these effects in inflammatory skin diseases, such as acne, atopic dermatitis, and psoriasis. Microbiome cosmetics can help restore skin barrier function and improve these diseases.

Bioelectric Signaling: Role of Bioelectricity in Directional Cell Migration in Wound Healing

In wound healing, individual cells' behaviors coordinate movement toward the wound center to restore small or large barrier defects. The migration of epithelial cells as a continuous sheet structure is one of the most important processes by which the skin barrier is restored. How such multicellular and tissue level movement is initiated upon injury, coordinated during healing, and stopped when wounds healed has been a research focus for decades. When skin is wounded, the compromised epithelial barrier generates endogenous electric fields (EFs), produced by ion channels and maintained by cell junctions. These EFs are present across wounds, with the cathodal pole at the wound center. Epithelial cells detect minute EFs and migrate directionally in response to electrical signals. It has long been postulated that the naturally occurring EFs facilitate wound healing by guiding cell migration. It is not until recently that experimental evidence has shown that large epithelial sheets of keratinocytes or corneal epithelial cells respond to applied EFs by collective directional migration. Although some of the mechanisms of the collective cell migration are similar to those used by isolated cells, there are unique mechanisms that govern the coordinated movement of the cohesive sheet. We will review the understanding of wound EFs and how epithelial cells and other cells important to wound healing respond to the electric signals individually as well as collectively. Mounting evidence suggests that wound bioelectrical signaling is an important mechanism in healing. Critical understanding and proper exploitation of this mechanism will be important for better wound healing and regeneration.

Selective Ablation of BCL11A in Epidermal Keratinocytes Alters Skin Homeostasis and Accelerates Excisional Wound Healing In Vivo

Transcriptional regulator BCL11A plays a crucial role in coordinating a suite of developmental processes including skin morphogenesis, barrier functions and lipid metabolism. There is little or no reports so far documenting the role of BCL11A in postnatal adult skin homeostasis and in the physiological process of tissue repair and regeneration. The current study establishes for the first time the In Vivo role of epidermal BCL11A in maintaining adult epidermal homeostasis and as a negative regulator of cutaneous wound healing. Conditional ablation of Bcl11a in skin epidermal keratinocytes (Bcl11a^ep−/−mice) enhances the keratinocyte proliferation and differentiation program, suggesting its critical role in epidermal homeostasis of adult murine skin. Further, loss of keratinocytic BCL11A promotes rapid closure of excisional wounds both in a cell autonomous manner likely via accelerating wound re-epithelialization and in a non-cell autonomous manner by enhancing angiogenesis. The epidermis specific Bcl11a knockout mouse serves as a prototype to gain mechanistic understanding of various downstream pathways converging towards the manifestation of an accelerated healing phenotype upon its deletion.

CLDN4 promotes growth of acute myeloid leukemia cells via regulating AKT and ERK1/2 signaling

Acute myeloid leukemia (AML) is the most common acute leukemia affecting adults. The tight junction protein CLDN4 is closely related to the development of various epithelial cell carcinomas. However, whether CLDN4 contributes to AML development remains unclear. For the first time, we found that expression of CLDN4 is aberrantly up-regulated in AML cells. Knockdown of CLDN4 expression resulted in a dramatic decreased cell growth, elevated apoptosis of AML cells. Further, we revealed that knockdown of CLDN4 inhibits mRNA expression of PIK3R3 and MAP2K2, thus suppresses activation of AKT and ERK1/2. More importantly, activating AKT branch by SC79 partially compromised CLDN4 knockdown induced cell viability inhibition. In addition, we found that higher expression of CLDN4 is connected to worse survival and is an independent indicator of shorter disease free survival (DFS) in AML patients. Together, our results indicate that CLDN4 contributes to AML pathogenesis, and suggests that targeting CLDN4 is a promising option for AML treatment.

Alpha-Lipoic Acid Promotes Intestinal Epithelial Injury Repair by Regulating MAPK Signaling Pathways

Intestinal epithelial cells are an essential barrier in human gastrointestinal tract, and healing of epithelial wound is a key process in many intestinal diseases. α-Lipoic acid (ALA) was shown to have antioxidative and anti-inflammatory effects, which could be helpful in intestinal epithelial injury repair. The effects of ALA in human colonic epithelial cells NCM460 and human colorectal adenocarcinoma cells Caco-2 were studied. ALA significantly promoted NCM460 and Caco-2 migration, increased mucosal tight junction factors ZO-1 and OCLN expression, and ALA accelerated cell injury repair of both cells in wound healing assay. Western blot analysis indicated that ALA inhibited a variety of mitogen-activated protein kinase (MAPK) signaling pathways in the epithelial cells. In conclusion, ALA was beneficial to repair of intestinal epithelial injury by regulating MAPK signaling pathways.

Melanoma secretion of transforming growth factor-β2 leads to loss of epidermal AMBRA1 threatening epidermal integrity and facilitating tumour ulceration

BACKGROUND

For patients with early American Joint Committee on Cancer (AJCC)-stage melanoma the combined loss of the autophagy regulatory protein AMBRA1 and the terminal differentiation marker loricrin in the peritumoral epidermis is associated with a significantly increased risk of metastasis.

OBJECTIVES

The aim of the present study was to evaluate the potential contribution of melanoma paracrine transforming growth factor (TGF)-β signalling to the loss of AMBRA1 in the epidermis overlying the primary tumour and disruption of epidermal integrity.

METHODS

Immunohistochemistry was used to analyse AMBRA1 and TGF-β2 in a cohort of 109 AJCC all-stage melanomas, and TGF-β2 and claudin-1 in a cohort of 30 or 42 AJCC stage I melanomas, respectively, with known AMBRA1 and loricrin (AMLo) expression. Evidence of pre-ulceration was analysed in a cohort of 42 melanomas, with TGF-β2 signalling evaluated in primary keratinocytes.

RESULTS

Increased tumoral TGF-β2 was significantly associated with loss of peritumoral AMBRA1 (P < 0·05), ulceration (P < 0·001), AMLo high-risk status (P < 0·05) and metastasis (P < 0·01). TGF-β2 treatment of keratinocytes resulted in downregulation of AMBRA1, loricrin and claudin-1, while knockdown of AMBRA1 was associated with decreased expression of claudin-1 and increased proliferation of keratinocytes (P < 0·05). Importantly, we show loss of AMBRA1 in the peritumoral epidermis was associated with decreased claudin-1 expression (P < 0·05), parakeratosis (P < 0·01) and cleft formation in the dermoepidermal junction (P < 0·05).

CONCLUSIONS

Collectively, these data suggest a paracrine mechanism whereby TGF-β2 causes loss of AMBRA1 overlying high-risk AJCC early-stage melanomas and reduced epidermal integrity, thereby facilitating erosion of the epidermis and tumour ulceration.

Cell-cell adhesion impacts epithelia response to substrate stiffness: Morphology and gene expression

Monolayer epithelial cells interact constantly with the substrate they reside on and their surrounding neighbors. As such, the properties of epithelial cells are profoundly governed by the mechanical and molecular cues that arise from both the substrate and contiguous cell neighbors. Although both cell-substrate and cell-cell interactions have been studied individually, these results are difficult to apply to native confluent epithelia, in which both jointly regulate the cell phenotype. Specifically, it remains poorly understood about the intertwined contributions from intercellular adhesion and substrate stiffness on cell morphology and gene expression, two essential microenvironment properties. Here, by adjusting the substrate modulus and altering the intercellular adhesion within confluent kidney epithelia, we found that cell-substrate and cell-cell interactions can mask each other's influence. For example, we found that epithelial cells exhibit an elongated morphological phenotype only when the substrate modulus and intercellular adhesions are both reduced, whereas their motility can be upregulated by either reduction. These results illustrate that combinatorial changes of the physical microenvironment are required to alter cell morphology and gene expression.

Skin barrier defects in atopic dermatitis: From old idea to new opportunity

Atopic dermatitis (AD) is the most common chronic skin inflammatory disease, with a profound impact on patients’ quality of life. AD varies considerably in clinical course, age of onset and degree to which it is accompanied by allergic and non-allergic comorbidities. Skin barrier impairment in both lesional and nonlesional skin is now recognized as a critical and often early feature of AD. This may be explained by a number of abnormalities identified within both the stratum corneum and stratum granulosum layers of the epidermis. The goal of this review is to provide an overview of key barrier defects in AD, starting with a historical perspective. We will also highlight some of the commonly used methods to characterize and quantify skin barrier function. There is ample opportunity for further investigative work which we call out throughout this review. These include: quantifying the relative impact of individual epidermal abnormalities and putting this in a more holistic view with physiological measures of barrier function, as well as determining whether these barrier-specific endotypes predict clinical phenotypes (e.g. age of onset, natural history, comorbidities, response to therapies, etc). Mechanistic studies with new (and in development) AD therapies that specifically target immune pathways, Staphylococcus aureus abundance and/or skin barrier will help us understand the dynamic crosstalk between these compartments and their relative importance in AD.

Keratinocyte and Fibroblast Wound Healing In Vitro Is Repressed by Non-Optimal Conditions but the Reparative Potential Can Be Improved by Water-Filtered Infrared A

It is a general goal to improve wound healing, especially of chronic wounds. As light therapy has gained increasing attention, the positive influence on healing progression of water-filtered infrared A (wIRA), a special form of thermal radiation, has been investigated and compared to the detrimental effects of UV-B irradiation on wound closure in vitro. Models of keratinocyte and fibroblast scratches help to elucidate effects on epithelial and dermal healing. This study further used the simulation of non-optimal settings such as S. aureus infection, chronic inflammation, and anti-inflammatory conditions to determine how these affect scratch wound progression and whether wIRA treatment can improve healing. Gene expression analysis for cytokines (IL1A, IL6, CXCL8), growth (TGFB1, PDGFC) and transcription factors (NFKB1, TP53), heat shock proteins (HSP90AA1, HSPA1A, HSPD1), keratinocyte desmogleins (DSG1, DSG3), and fibroblast collagen (COL1A1, COL3A1) was performed. Keratinocyte and fibroblast wound healing under non-optimal conditions was found to be distinctly reduced in vitro. wIRA treatment could counteract the inflammatory response in infected keratinocytes as well as under chronic inflammatory conditions by decreasing pro-inflammatory cytokine gene expression and improve wound healing. In contrast, in the anti-inflammatory setting, wIRA radiation could re-initiate the acute inflammatory response necessary after injury to stimulate the regenerative processes and advance scratch closure.

Treatment of acute wounds in hand with Calendula officinalis L.: A randomized trial

Most injuries in the hand and fingers, especially on the digital pulps, are suited for healing by secondary intention. Nevertheless, delay in epithelization seems to unfavorably restrict this technique. The purpose of this controlled randomized clinical trial is to analyze by means of photo planimetry the progression of the healing process by secondary intention in acute wounds of the hand using the standardized extract of Calendula officinalis L. (SEC). The cohort of eligible participants included two groups of 20 patients with skin loss in the hand and fingers treated by secondary intention. Control group (CG) used mineral oil and intervention group (IG) received SEC. Wound pictures were captured at each outpatient assessment until epithelization was achieved and measured with ImageJ. Intervention group (IG) and control group (CG) with 19 wounds each, primarily formed by men in their 40's with wounds in their index and ring fingers on the left side, showed homogeneous variables and similar initial wound areas. Epithelization time was shorter and healing speed was faster in IG (IG = 8.6 ± 4.7 days and 9.5 ± 5.8%day versus CG = 13.2 ± 7.4 days and 6.2 ± 2.9%day, ƿ < 0.05), leading to the conclusion that healing by secondary intention in acute wounds of the hand and fingers with SEC led to a faster epithelization.

Bioactive glass promotes the barrier functional behaviors of keratinocytes and improves the Re-epithelialization in wound healing in diabetic rats

Upon skin injury, re-epithelialization must be triggered promptly to restore the integrity and barrier function of the epidermis. However, this process is often delayed or interrupted in chronic wounds like diabetic foot ulcers. Considering that BG particles can activate multiple genes in various cells, herein, we hypothesized that bioactive glass (BG) might be able to modulate the barrier functional behaviors of keratinocytes. By measuring the transepithelial electrical resistance (TEER) and the paracellular tracer flux, we found the 58S-BG extracts substantially enhanced the barrier function of keratinocyte monolayers. The BG extracts might exert such effects by promoting the keratinocyte differentiation and the formation of tight junctions, as evidenced by the increased expression of critical differentiation markers (K10 and involucrin) and TJ protein claudin-1, as well as the altered subcellular location of four major TJ proteins (claudin-1, occludin, JAM-A, and ZO-1). Besides, the cell scratch assay showed that BG extracts induced the collective migration of keratinocytes, though they did not accelerate the migration rate compared to the control. The in vivo study using a diabetic rat wound model demonstrated that the BG extracts accelerated the process of re-epithelialization, stimulated keratinocyte differentiation, and promoted the formation of tight junctions in the newly regenerated epidermis. Our findings revealed the crucial effects of BGs on keratinocytes and highlighted its potential application for chronic wound healing by restoring the barrier function of the wounded skin effectively.

A designer cell culture insert with a nanofibrous membrane toward engineering an epithelial tissue model validated by cellular nanomechanics

Engineered platforms for culturing cells of the skin and other epithelial tissues are useful for the regeneration and development of in vitro tissue models used in drug screening. Recapitulating the biomechanical behavior of the cells is one of the important hallmarks of successful tissue generation on these platforms. The biomechanical behavior of cells profoundly affects the physiological functions of the generated tissue. In this work, a designer nanofibrous cell culture insert (NCCI) device was developed, consisting of a free-hanging polymeric nanofibrous membrane. The free-hanging nanofibrous membrane has a well-tailored architecture, stiffness, and topography to better mimic the extracellular matrix of any soft tissue than conventional, flat tissue culture polystyrene (TCPS) surfaces. Human keratinocytes (HaCaT cells) cultured on the designer NCCIs exhibited a 3D tissue-like phenotype compared to the cells cultured on TCPS. Furthermore, the biomechanical characterization by bio-atomic force microscopy (Bio-AFM) revealed a markedly altered cellular morphology and stiffness of the cellular cytoplasm, nucleus, and cell-cell junctions. The nuclear and cytoplasmic moduli were reduced, while the stiffness of the cellular junctions was enhanced on the NCCI compared to cells on TCPS, which are indicative of the fluidic state and migratory phenotype on the NCCI. These observations were corroborated by immunostaining, which revealed enhanced cell-cell contact along with a higher expression of junction proteins and enhanced migration in a wound-healing assay. Taken together, these results underscore the role of the novel designer NCCI device as an in vitro platform for epithelial cells with several potential applications, including drug testing, disease modeling, and tissue regeneration.

Effect of 3D-Fibroblast Dermis Constructed by Layer-by-Layer Cell Coating Technique on Tight Junction Formation and Function in Full-Thickness Skin Equivalent

Human skin equivalents (HSEs) consisting of an epidermis and dermis have been used as promising tools for drug evaluation and for clinical applications in regenerative medicine. Normal human dermal fibroblasts (NHDFs) are essential for the fabrication of HSEs because they play an important role in the maturation of the epidermis. Recently, epidermal tight junctions (TJs), which are complex cell-cell junctions, have attracted much attention as a second barrier and regulator for other barrier functions. In a previous study, we revealed the expression of TJ-related proteins and the time course of formation of TJ structure in the HSE (layer-by-layer (LbL)-three-dimensional (3D) Skin) constructed by layer-by-layer (LbL) cell coating technique that have a unique dermis consisting of NHDFs only (3D-fibroblast dermis). However, the effect of the 3D-fibroblast dermis on the formation of functional epidermal TJs is unknown. In this study, we investigated the effect of the 3D-fibroblast dermis on the expression of TJ-related proteins and TJ function in LbL-3D Skin. We demonstrated that the 3D-fibroblast dermis affects the long-term expression of TJ-related proteins and the formation of TJ with barrier function in the epidermis. These results show that the 3D-fibroblast dermis in LbL-3D Skin contributes to the formation and maintenance of functional TJs as in native human skin by direct contact with KCs.

CLDN1 regulates trophoblast apoptosis and proliferation in preeclampsia

Preeclampsia is a gestational hypertensive disease; however, preeclampsia remains poorly understood. Bioinformatics analysis was applied to find novel genes involved in the pathogenesis of preeclampsia and identified CLDN1 as one of the most differentially expressed genes when comparing patients with preeclampsia and healthy controls. The results of the qRT-PCR, Western blotting and immunohistochemistry experiments demonstrated that CLDN1 was significantly downregulated in the chorionic villi in samples from patients with preeclampsia. Furthermore, knockdown of CLDN1 in HTR-8/SVneo cells resulted in the inhibition of proliferation and induction of apoptosis, and overexpression of CLDN1 reversed these effects. In addition, RNA-seq assays demonstrated that the gene BIRC3 is potentially downstream of CLDN1 and is involved in the regulation of apoptosis. Knockdown of CLDN1 confirmed that the expression level of BIRC3 was obviously decreased and was associated with a significant increase in cleaved PARP. Interestingly, the apoptotic effect in CLDN1 knockdown cells was rescued after BIRC3 overexpression. Overall, these results indicate that a decrease in CLDN1 inhibits BIRC3 expression and increases cleaved PARP levels thus participating in the pathogenesis of preeclampsia.

Polysaccharides in natural products that repair the damage to intestinal mucosa caused by cyclophosphamide and their mechanisms: A review

Cyclophosphamide (CTX) is a commonly used antitumor drug in clinical practice, and intestinal mucosal injury is one of its main toxic side effects, which seriously affects the treatment tolerance and prognosis of patients. Therefore, the prevention of intestinal mucosal injury is a research hotspot. Studies have shown that polysaccharides can effectively prevent and improve CTX-induced intestinal mucosal injury and immune system disorders. Recent research has elucidated the structure, biological function, and physicochemical properties of polysaccharides that prevent intestinal mucosal injury, and the potential mechanisms whereby they have this effect. In this paper, we review the recent progress made in understanding the effects of polysaccharides on intestinal mucosal injury and their protective mechanism in order to provide a reference for further research on the prevention of intestinal mucosal injury and the mechanisms involved in nutritional intervention.

MicroRNA-185 inhibits the proliferation and migration of HaCaT keratinocytes by targeting peroxisome proliferator-activated receptor β

Proliferation and migration of keratinocytes are major processes of skin wound repair after injury. It has been indicated that microRNAs (miRNAs/miRs) are associated with the proliferation and migration of keratinocytes. However, the mechanism by which miR-185 affects these processes in keratinocytes remains unclear. In the present study, the expression level of miR-185 and peroxisome proliferator-activated receptor β (PPARβ) was examined by reverse transcription-quantitative PCR in HaCaT keratinocytes. Cell proliferation was evaluated using Cell Counting Kit-8 and colony formation assays. Western blot analysis was used to detect the levels of cell proliferation, migration and PI3K/AKT signaling pathway-associated proteins. In addition, the migratory capacity of the cells was determined using Transwell assay. The target gene of miR-185 was verified using dual-luciferase reporter assay. The results indicated that overexpression of miR-185 inhibited proliferation, migration and activation of the PI3K/AKT signaling pathway in HaCaT keratinocytes. PPARβ was indicated to be a target of miR-185 and its overexpression promoted the proliferation and migration of HaCaT keratinocytes, while its knockdown exhibited the adverse effects. Furthermore, PI3K inhibitor LY294002 inhibited activation of the PI3K/AKT signaling pathway and decreased the proliferation and migration of HaCaT keratinocytes. In addition, overexpressed PPARβ reversed the suppressive effects of miR-185 overexpression on proliferation, migration and activation of the PI3K/AKT signaling pathway. In conclusion, the results of the present study demonstrated that miR-185 suppressed activation of the PI3K/AKT signaling pathway via targeting PPARβ, thereby regulating proliferation and migration in HaCaT keratinocytes. The present study provided a novel theoretical basis for the use of miR-185 as a target in wound repair.

Further assessment of Salvia haenkei as an innovative strategy to counteract skin photo-aging and restore the barrier integrity

Skin is the essential barrier of the human body which performs multiple functions. Endogenous factors, in concert with external assaults, continuously affect skin integrity, leading to distinct structural changes that influence not only the skin appearance but also its various physiological functions. Alterations of the barrier functions lead to an increased risk of developing disease and side reactions, thus the importance of maintaining the integrity of the epidermal barrier and slowing down the skin aging process is evident.

Salvia haenkei (SH) has been recently identified as a potential anti-senescence agent; its extract is able to decrease the level of senescent cells by affecting the IL1α release and reducing reactive oxygen species (ROS) generation.

In this study, SH extract was tested on human keratinocyte cell line (HaCaT) exposed to stress factors related to premature aging of cells such as free radicals and ultraviolet B radiation. We confirmed that SH acts as scavenger of ROS and found its ability to restore the skin barrier integrity by reinforcing the cytoskeleton structure, sealing the tight junctions and increasing the migration rate of cells.

Given these results, this work becomes relevant, identifying Salvia haenkei as a compound useful for anti-aging skin treatment in clinical performance.

Kaempferol attenuates diquat-induced oxidative damage and apoptosis in intestinal porcine epithelial cells

Kaempferol, a flavonol component of plants, is well-known to exhibit multiple bioactivities, such as anti-oxidative and anti-apoptotic effects. However, the underlying mechanisms responsible for the beneficial effects remain elusive. This study was conducted to test the hypothesis that kaempferol attenuated diquat-induced oxidative damage and intestinal barrier dysfunction by ameliorating oxidative damage and apoptosis in intestinal porcine epithelial cells. Compared with the control group, diquat treatment led to enhanced intracellular ROS production, increased mitochondrial depolarization, and apoptosis, which were accompanied by cell cycle arrest at the G1 phase, reduced cell migration, and disrupted intestinal epithelial barrier function. These effects triggered by diquat were reversed by kaempferol. Further study showed that the protective effect of kaempferol was associated with an enhanced mRNA level of genes related to cell cycle progression (cyclin D1, CDK4, and E2F1) and genes implicated in the anti-oxidant system (GSR, GSTA4, and HO-1), up-regulated abundance of tight junctions (ZO-1, ZO-2, occludin, and claudin-4), as well as enhanced Nrf2, an anti-oxidant transcription factor. In conclusion, we revealed a functional role of kaempferol in the intestinal barrier. Ingestion of kaempferol-rich foods might be a potential strategy to improve the integrity and function of enterocytes.

Claudin-1 and Claudin-3 as Molecular Regulators of Myelination in Leukoaraiosis Patients

OBJECTIVES

Leukoaraiosis is described as white matter lesions that are associated with cognitive dysfunction, neurodegenerative disorders, etc. Myelin depletion is a salient pathological feature of, and the loss of oligodendrocytes is one of the most robust alterations evident in, white matter degeneration. Recent studies have revealed that claudin proteins are aberrantly expressed in leukoaraiosis and regulate oligodendrocyte activity. However, the roles of claudin-1 and claudin-3 in oligodendrocytes and leukoaraiosis are still not well-defined.

METHODS

Quantitative polymerase chain reaction was used to measure the expression of claudin-1 (CLDN1), claudin-3 (CLDN3), and myelinogenesis-related genes such as myelin basic protein (MBP), proteolipid protein (PLP), oligodendrocyte transcription factor 2 (OLIG2), and SRY-box transcription factor 10 (SOX10) in leukoaraiosis patients (n=122) and healthy controls (n=122). The expression of claudin-1 and claudin-3 was either ectopically silenced or augmented in Oli-neu oligodendrocytes, and colony formation, apoptosis, and migration assays were performed. Finally, the expression of myelin proteins was evaluated by western blotting.

RESULTS

Our results revealed that in addition to SOX10, the expression levels of claudin-1, claudin-3, and myelinogenesis-related proteins were prominently downregulated in leukoaraiosis patients, compared to those in healthy controls. Furthermore, the growth and migration of Oli-neu cells were downregulated upon silencing claudin-1 or claudin-3. However, the overexpression of claudin-1 or claudin-3 resulted in the reduction of the degree of apoptosis in Oli-neu cells. In addition, claudin-1 and claudin-3 promoted the expression of MBP, OLIG2, PLP, and SOX10 at the translational level.

CONCLUSION

Our data has demonstrated that the abnormal expression of claudin-1 and claudin-3 regulates the pathological progression of leukoaraiosis by governing the viability and myelination of oligodendrocytes. These findings provide novel insights into the regulatory mechanisms underlying the roles of claudin-1 and claudin-3 in leukoaraiosis.

Differences of the tumour cell glycocalyx affect binding of capsaicin-loaded chitosan nanocapsules

The glycocalyx regulates the interaction of mammalian cells with extracellular molecules, such as cytokines. However, it is unknown to which extend the glycocalyx of distinct cancer cells control the binding and uptake of nanoparticles. In the present study, exome sequencing data of cancer patients and analysis of distinct melanoma and bladder cancer cell lines suggested differences in cancer cell-exposed glycocalyx components such as heparan sulphate. Our data indicate that glycocalyx differences affected the binding of cationic chitosan nanocapsules (Chi-NCs). The pronounced glycocalyx of bladder cancer cells enhanced the internalisation of nanoencapsulated capsaicin. Consequently, capsaicin induced apoptosis in the cancer cells, but not in the less glycosylated benign urothelial cells. Moreover, we measured counterion condensation on highly negatively charged heparan sulphate chains. Counterion condensation triggered a cooperative binding of Chi-NCs, characterised by a weak binding rate at low Chi-NC doses and a strongly increased binding rate at high Chi-NC concentrations. Our results indicate that the glycocalyx of tumour cells controls the binding and biological activity of nanoparticles. This has to be considered for the design of tumour cell directed nanocarriers to improve the delivery of cytotoxic drugs. Differential nanoparticle binding may also be useful to discriminate tumour cells from healthy cells.

Asymptomatic Hyperamylasemia in Stevens-Johnson Syndrome Is Associated with Intestinal Barrier Dysfunction

Methods

A retrospective study on SJS patients was conducted at a tertiary medical center. All patients diagnosed as SJS, with available serum amylase index, were included. Clinical data of all subjects were retrospectively collected and analyzed. Colonic mucosal biopsies were obtained to measure tight junction protein expression.

Results

A total of nine patients were included in the present study for study analysis. The average serum amylase of the study cohort was 228.78 ± 204.18 U/L. Among which, five patients had a positive fecal occult blood test (FOBT). Colonic mucosal biopsies were obtained and stained with occludin and zonula occludens-1 (ZO-1). The expression of occludin and ZO-1 was significantly downregulated in SJS patients (p < 0.01), which was indicative of intestinal barrier dysfunction.

Conclusion

Hyperamylasemia often extends beyond pancreatic diseases. Clinical awareness of asymptomatic hyperamylasemia secondary to other systemic diseases can help avoid unnecessary overexamination and overtreatment.

Scratching damages tight junctions through the Akt-claudin 1 axis in atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a common, chronic, severely pruritic, eczematous skin disease that seriously deteriorates the quality of life of patients. Scratching is a cardinal symptom of AD. Although the vicious itch-scratch cycle continues and aggravates skin barrier dysfunction in AD, how scratching induces skin barrier dysfunction through tight junctions remains unclear.

AIM

To study the effect of scratching on tight junctions in the itch-scratch cycle.

METHODS

Scratching behaviour and skin barrier dysfunction on the neck and back in an AD mouse model were assessed. The expression of tight junction proteins was compared between the neck and back mice, and the mechanisms underlying the involvement of Akt/CLDN1 pathways in this process were explored.

RESULTS

We used oxazolone to induce AD on the neck or back of mice. There was significantly more scratching behaviour and more pronounced skin barrier dysfunction with the neck than with the back. Downregulation of claudin-1 (CLDN1) and upregulation of Akt phosphorylation in skin were well correlated with scratching behaviour in this AD model. Furthermore, SC79, an agonist of Akt phosphorylation, could downregulate CLDN1 expression in HaCaT cells. An antagonist of Akt phosphorylation (LY294002) was used to treat the AD mice; this treatment rescued CLDN1 expression through inhibiting Akt phosphorylation in skin, and importantly, also inhibited the scratching behaviour induced by AD.

CONCLUSION

The results reveal the underlying mechanism of tight junction damage promoted by scratching in the itch-scratch cycle of AD, and opens a new avenue to pruritus management in AD, through Akt antagonists.

Labdane-Type Diterpenes from the Aerial Parts of Rydingia persica: Their Absolute Configurations and Protective Effects on LPS-Induced Inflammation in Keratinocytes

Phytochemical investigations of an extract of the aerial parts of Rydingia persica led to the isolation of 14 labdane-type diterpenoids, of which compounds 1-5, 8, and 12-14 turned out to be new natural products, while the remaining compounds were isolated for the first time from the genus Rydingia. Their structures were elucidated using 1D- and 2D-NMR and mass spectrometry, and their absolute configurations were determined by quantum chemical calculation methods. Furthermore, DP4+ NMR chemical shift probability calculations were performed for compounds 12-14, in order to elucidate the orientation of the ambiguous chiral center at C-15, prior to absolute configuration determination. The methanol extract of the aerial parts of R. persica along with subfractions obtained and selected isolated compounds were evaluated for their effects on inflammation-related factors such as nitrotyrosine formation, IL-6 release, and TNF-α release, along with tight-junction proteins claudin-1 and occludin expression in LPS-stimulated HaCaT cells. Occludin and claudin-1 are tight-junction proteins, which play a pivotal role in wound repair mechanisms. Overall, the subfractions and compounds isolated showed moderate to high activity, indicating that labdane-type diterpenoids contribute to the anti-inflammatory and wound-healing activity of R. persica.

A pan-cancer blueprint of the heterogeneous tumor microenvironment revealed by single-cell profiling

The stromal compartment of the tumor microenvironment consists of a heterogeneous set of tissue-resident and tumor-infiltrating cells, which are profoundly moulded by cancer cells. An outstanding question is to what extent this heterogeneity is similar between cancers affecting different organs. Here, we profile 233,591 single cells from patients with lung, colorectal, ovary and breast cancer (n = 36) and construct a pan-cancer blueprint of stromal cell heterogeneity using different single-cell RNA and protein-based technologies. We identify 68 stromal cell populations, of which 46 are shared between cancer types and 22 are unique. We also characterise each population phenotypically by highlighting its marker genes, transcription factors, metabolic activities and tissue-specific expression differences. Resident cell types are characterised by substantial tissue specificity, while tumor-infiltrating cell types are largely shared across cancer types. Finally, by applying the blueprint to melanoma tumors treated with checkpoint immunotherapy and identifying a naïve CD4⁺ T-cell phenotype predictive of response to checkpoint immunotherapy, we illustrate how it can serve as a guide to interpret scRNA-seq data. In conclusion, by providing a comprehensive blueprint through an interactive web server, we generate the first panoramic view on the shared complexity of stromal cells in different cancers.

A Novel Composite Biomaterial Made of Jellyfish and Porcine Collagens Accelerates Dermal Wound Healing by Enhancing Reepithelization and Granulation Tissue Formation in Mice

Background and Objective: Impaired dermal wound healing represents a major medical issue in today's aging populations. Granulation tissue formation in the dermis and reepithelization of the epidermis are both important and necessary for proper wound healing. Although a number of artificial dermal grafts have been used to treat full-thickness dermal loss in humans, they do not induce reepithelization of the wound, requiring subsequent epithelial transplantation. In the present study, we sought a novel biomaterial that accelerates the wound healing process. Approach: We prepared a composite biomaterial made of jellyfish and porcine collagens and developed a hybrid-type dermal graft that composed of the upper layer film and the lower layer sponge made of this composite biomaterial. Its effect on dermal wound healing was examined using a full-thickness excisional wound model. Structural properties of the dermal graft and histological features of the regenerating skin tissue were characterized by electron microscopic observation and immunohistological examination, respectively. Results: The composite biomaterial film stimulated migration of keratinocytes, leading to prompt reepithelization. The regenerating epithelium consisted of two distinct cell populations: keratin 5-positive basal keratinocytes and more differentiated cells expressing tight junction proteins such as claudin-1 and occludin. At the same time, the sponge made of the composite biomaterial possessed a significantly enlarged intrinsic space and enhanced infiltration of inflammatory cells and fibroblasts, accelerating granulation tissue formation. Innovation: This newly developed composite biomaterial may serve as a dermal graft that accelerates wound healing in various pathological conditions. Conclusion: We have developed a novel dermal graft composed of jellyfish and porcine collagens that remarkably accelerates the wound healing process.