Tissue Barriers最新文献

Eph receptor-interacting proteins (ephrin) ligands and their erythropoietin-producing human hepatocellular (Eph) receptors elicit bidirectional signals that regulate cell migration, angiogenesis, neuronal plasticity, and other developmental processes in the embryo. In adulthood, ephrin-Eph signaling regulates numerous homeostatic events, including epithelial cell proliferation and differentiation. Epithelial surfaces, including those of skin and vagina, are lined by layers of stratified squamous epithelium (SSE) that protect against mechanical stress and microbial pathogen invasion. Ephrin-Eph signaling is known to promote cutaneous epithelial barrier function by regulating the expression of specialized cell-cell adhesion junctions termed desmosomes, but the role of this signaling system in maintaining epithelial integrity and barrier function in the vagina is less explored. This review summarizes current understanding of ephrin-Eph signaling that regulates desmosome expression and barrier function in the skin and considers evidence that suggests ephrin-Eph signaling similarly regulates these processes in vaginal SSE.

In vitro models are of great importance in advancing our understanding of human diseases, especially complex disorders with unknown etiologies like inflammatory bowel diseases (IBD). One of the key IBD features is the increased intestinal permeability. The disruption of the intestinal barrier can occur due to a destructive inflammatory response involving intestinal cell death. Alternatively, proteins that form tight junctions (TJ) fail to form function complexes and promote epithelial barrier disruption. The mechanisms behind this process are not fully understood. Thus, in vitro models that facilitate studying the intestinal barrier and its molecular components are of particular importance in the context of IBD. There are in vitro and ex vivo models that can be used to recapitulate some aspects of IBD. Among these are intestinal explants, crypts, and epithelial 3D-organoids. Here we describe some practical limitations of isolated crypts, gut tissue explants, and intestinal organoids as models in epithelial barrier biology, and TJ in particular. Our findings demonstrate that only 3D intestinal organoids formed from single cells are suitable to study barrier permeability in vitro, as primary crypt-derived organoids do not retain epithelial integrity due to cell death. Importantly, 3D organoids raised in culture conditions may fail to recapitulate inflammatory and barrier phenotypes of the source mouse model. To study the features of the inflamed epithelium, ex vivo intestinal explants and crypts were employed. We show here that isolated crypts do not preserve native TJ structure in a long-term experimental setting and tend to disintegrate in the unsupported culture environment. However, intestinal explants were stable in culture conditions for about 24 hours and demonstrated their applicability for short-term living tissue imaging and fluorescence recovery after photobleaching (FRAP). Thus, a combination of 3D organoids and intestinal explants provides a more accurate experimental platform to understand the intestinal epithelial barrier.

Friedreich's Ataxia (FRDA) is a neurodegenerative disease that affects a variety of different organ systems. The disease is caused by GAA repeat expansions in intron 1 of the Frataxin gene (FXN), which results in a decrease in the expression of the FXN protein. FXN is needed for the biogenesis of iron-sulfur clusters (ISC) which are required by key metabolic processes in the mitochondria. Without ISCs those processes do not occur properly. As a result, reactive oxygen species accumulate, and the mitochondria cease to function. Iron is also thought to accumulate in the cells of certain tissue types. These processes are thought to be intimately related to the pathologies affecting a myriad of tissues in FRDA. Most FRDA patients suffer from loss of motor control, cardiomyopathy, scoliosis, foot deformities, and diabetes. In this review, we discuss the known features of FRDA pathology and the current understanding about the basis of these alterations.

The entry of bacterial-derived lipopolysaccharides (LPS) from the intestinal lumen to the circulation induces low-grade systemic inflammation. We have found that LPS is transcellularly transported to the portal vein during luminal long-chain fatty acid (LCFA) exposure via CD36- and lipid raft-mediated pathways in rat jejunum, consistent with the involvement of caveolae-mediated endocytosis. We thus examined LPS transport in wild-type (WT) and caveolin-1 (Cav1) knockout (KO) murine jejunum. FITC-LPS was added to the mucosal bath of Ussing chambered muscle-stripped jejunal mucosa of WT and Cav1KO mice. Serosal appearance of FITC-LPS was measured with or without luminal application of oleic acid (OA, 10 mM) with taurocholic acid (TCA, 0.1 mM), or medium-chain fatty acid (MCFA) sodium caprate (C10, 30 mM). Luminal application of OA/TCA increased FITC-LPS m-to-s transport in WT jejunum, inhibited by the CD36 inhibitor sulfosuccinimidyl oleate or lipid raft inhibitor methyl-β-cyclodextrin, though not by the clathrin inhibitor chlorpromazine or Pitstop2, suggesting that LCFA-induced LPS transport is mediated by caveolae-mediated endocytosis. In contrast, OA/TCA-induced FITC-LPS transport was abolished in Cav1KO jejunum. Nevertheless, luminal C10 increased FITC-LPS transport in both WT and Cav1KO jejuna without transepithelial electrical resistance changes. Chlorpromazine and Pitstop2 inhibited C10-induced FITC-LPS transport, suggesting that C10 enhances transcellular LPS transport via clathrin-mediated endocytosis in the jejunum. These results suggest that LPS transport during LCFA exposure is mediated by Cav1-mediated endocytosis, whereas MCFA-induced LPS transport is via clathrin-mediated endocytosis. Modulation of epithelial endocytosis may be a new therapeutic target for the prevention of dietary lipid -associated endotoxemia, including the metabolic syndrome.

Sinonasal inverted papilloma (SNIP) is a benign epithelial neoplasm of the Schneiderian membrane, known for its locally aggressive behavior, high recurrence rates, and potential for malignant transformation into sinonasal squamous cell carcinoma (SNSCC). Emerging evidence emphasizes the role of microRNAs (miRNAs) in the pathogenesis, progression, and clinical management of SNIP. These small non-coding RNAs regulate key cellular pathways, particularly the PTEN/PI3K/AKT axis, which governs tumor growth, apoptosis resistance, and chemoresistance. Among the miRNAs studied, miR-296-3p, miR-214-3p, and the miR-449 cluster show significant dysregulation. miR-296-3p is upregulated in SNSCC, promoting oncogenesis by inhibiting PTEN and activating the PI3K/Akt pathway. Conversely, miR-214-3p is downregulated in SNIP and correlates with advanced disease and increased recurrence, identifying it as a potential diagnostic and prognostic biomarker. The miR-449 cluster, with known tumor-suppressive properties, is progressively downregulated during malignant transformation, highlighting its role in maintaining epithelial structure. Despite their promise, clinical application of miRNA-based diagnostics and therapies faces challenges such as delivery optimization, specificity, and off-target effects. Nonetheless, the noninvasive detection of circulating miRNAs in bodily fluids offers a compelling approach for future diagnostic tools and patient monitoring. This review highlights the transformative potential of miRNA research in advancing SNIP diagnosis and treatment. By integrating molecular insights into clinical practice, miRNA-based strategies could pave the way for more personalized interventions, ultimately reducing recurrence rates and preventing malignant transformation.

Lipolysis-stimulated lipoprotein receptor (LSR), a lipid metabolism-related factor localized in tricellular tight junctions (tTJs), plays an important role in maintaining the epithelial homeostasis. LSR is highly expressed in well-differentiated cancers, and its expression decreases during malignancy. The LSR antibody inhibits cell growth and promotes apoptosis in some cancers. Histone deacetylases (HDACs) are thought to play a crucial role in carcinogenesis, and HDAC inhibitors promote differentiation and prevent cell proliferation and migration in cancers. HDAC inhibitors together with TNFα also induce apoptosis via TNFα-related apoptosis-inducing ligand (TRAIL) in some cancers. In this study, we investigated the apoptosis signaling induced by an anti-LSR antibody in human salivary duct adenocarcinoma (SDC) cell line A253, compared to TRAIL-induced apoptosis. A253 cells were treated with human recombinant TNFα with or without HDAC inhibitor trichostatin A (TSA) and quisinostat (JNJ-26481585). Treatment using TNFα with HDAC inhibitors markedly induced apoptosis in A253 cells and the anti-TNFα antibody prevented the induced apoptosis. A253 cells were treated with an antibody against the extracellular N-terminal domain of human LSR (LSR-N-ab) with or without HDAC inhibitors. Treatment with HDAC inhibitors induced LSR expression in the membranes of A253 cells. Treatment using LSR-N-ab with HDAC inhibitors markedly promoted apoptosis in A253 cells. The tricellular signaling pathway JNK inhibitor SP600125 and Hippo pathway MST1/2 inhibitor XMU-MP-1 prevented the apoptosis induced by treatment using TNFα or LSR-N-ab with HDAC inhibitors. Our findings indicated that treatment with TNFα or LSR-N-ab with HDAC inhibitors might be useful in the therapy for human SDC by enhancing apoptosis.

Modulation of claudin-based bicellular tight junction (TJ) and angulin-based tricellular TJ seals has been shown to enhance mucosal permeation of macromolecules, by using the receptor-binding fragments of Clostridium perfringens enterotoxin (C-CPE194, C-CPEmt, and C-CPEm19) and Clostridium perfringens iota-toxin (angubindin-1) as claudin modulators and an angulin modulator, respectively. Here, we compared the activity of these modulators on the TJ in human intestinal Caco-2 cells. All the claudin modulators loosened TJ integrity more potently compared to angubindin-1 with the order of potency being C-CPEm19 > C-CPE194 > C-CPEmt, and results for permeation enhancement were similar. Treatment with C-CPEmt and C-CPE194 at 100 µg/mL for 48 h enhanced the permeation of dextran sized 20 kDa and 70 kDa, respectively. Treatment with C-CPEm19 at 30 µg/mL for 48 h enhanced permeation of dextran with a molecular mass of up to 150 kDa. Furthermore, co-treatment of bicellular TJ modulators, such as C-CPEmt, C-CPE194, and C-CPEm19, and tricellular TJ modulators, such as angubindin-1, showed additive TJ-loosening and permeation-enhancing activities compared with individual treatments; specifically, C-CPEm19 and angubindin-1 co-treatment increased permeation of large molecules (70 kDa and 150 kDa). These findings indicate that TJ modulators may be used as size-selective permeation enhancers.

Crohn's disease is a form of inflammation that affects the gastrointestinal (GI) tract. It is characterized by persistent inflammation in the gut, which can lead to the formation of abnormal connections called fistulas. These fistulas can occur between the GI tract and the abdominal cavity, adjacent organs, or the skin. The most prevalent type of fistula in Crohn's disease patients is the perianal fistula, which forms between the rectum and the skin near the anus. Although the exact cause of fistula formation is not fully understood, research suggests that factors such as epithelial to mesenchymal transition, matrix metalloproteinase, immune system dysregulation, and microbiota may contribute to their development. There is currently no definitive treatment for fistula closure, but options include surgery, endoscopic procedures, antibiotics, biologic agents, and immunosuppressive drugs. These treatments can be used alone or in combination. However, recurrence is a significant challenge that needs to be addressed in the case of fistula treatment. This review provides an overview of the common types of fistulas, their characteristics, the main factors and mechanisms of fistula formation, and available therapeutic options.

Background: Oncostatin M (OSM) may be involved in the promotion of mucosal epithelial barrier dysfunction in patients with eosinophilic chronic rhinosinusitis with nasal polyps (Eos CRSwNP) by inducing matrix metalloproteinase (MMP) -1 and -7. The aim was to evaluate the roles and mechanisms of action of OSM on MMP-1 and -7 synthesis from nasal epithelial cells (NECs).

Methods: OSM, OSM receptor (OSMR), MMP-1 and -7 expression was evaluated in nasal mucosa or primary NECs from scrapings by quantitative polymerase chain reaction (qPCR), immunofluorescence and immunohistochemistry. OSM and other cytokines were used to stimulate air-liquid interface (ALI) cultured NECs. qPCR, enzyme-linked immunosorbent assay (ELISA) and immunofluorescence were used to evaluate the expression of OSMR, MMP-1, -7 and occludin in NECs.

Results: Elevated levels of OSMRβ, MMP-1 and -7 were found in the tissues and scraped NECs of Eos CRSwNP in comparison to them obtained from the inferior turbinate (IT) and control subjects. The levels of OSM and OSMRβ mRNA in tissues were positively correlated with the levels of MMP-1 and -7. OSM stimulation of NECs increased the expression of MMP-1 and -7, and the responses were suppressed by a STAT3 inhibitor, and a PI3K inhibitor respectively. In parallel studies, we found that stimulation with OSM disrupted the localization of occludin, a tight junction protein in NECs. The response was suppressed by a pan-MMP inhibitor.

Conclusion: OSM induces the synthesis and release of MMP-1 and -7 in NECs. Furthermore, MMP-1 and -7 promote mucosal epithelial barrier dysfunction in patients with Eos CRSwNP.

Dengue virus (DENV) infections are commonly reported in the tropical and subtropical regions of the world. DENV is reported to exploit various strategies to cross the blood-brain barrier. The NS1 protein of DENV plays an important role in viral neuropathogenesis, resulting in endothelial hyperpermeability and cytokine-induced vascular leak. miRNAs are short non-coding RNAs that play an important role in post-transcriptional gene regulations. However, no comprehensive information about the involvement of miRNAs in DENV-NS1-mediated neuropathogenesis has been explored to date. We observed that DENV-NS1 significantly alters the cellular miRNome of human cerebral microvascular endothelial cells in a bystander fashion. Subsequent target prediction and pathway enrichment analysis indicated that these microRNAs and their corresponding target genes are involved in pathways associated with blood-brain barrier dysfunction such as "Adherens junction" and "Tight junction". Additionally, several miRNA-mRNA pairs were also found to be involved in cellular signaling pathways related to cytokine production, for instance, "Jak-STAT signaling pathway", "Chemokine signaling pathway", "IL-17 signaling pathway", "NF-κB signaling pathway", and "Viral protein interaction with cytokine and cytokine receptor". The dysregulated production of inflammatory cytokines is reported to compromise BBB permeability. This study is the first report to demonstrate that DENV-NS1-mediated miRNA perturbations are crucial in compromising endothelial barrier integrity. It also offers insights into potential therapeutic targets to mitigate DENV-NS1-induced vascular permeability and inflammation.