Pogostemon cablin essential oil as feed additive promotes the repair of the rumen epithelial barrier in heat-stressed beef cattle.

Pogostemon cablin essential oil (PEO), extracted from P. cablin, has anti-oxidant, anti-inflammatory, and anti-stress properties, as well as the ability to improve gastrointestinal digestion. This study aims to evaluate the effects of PEO on the performance, rumen epithelial morphology, and barrier function in heat-stressed beef cattle. Thirty-six male Jingjiang cattle at 18 months old were randomly assigned into four groups and fed a diet containing PEO at 0 (control), 50, 100, or 150 mg/kg in the feed concentrate (n = 9). All experimental cattle were fed under high temperature and humidity in summer for 60 days. The results indicated that 50 mg/kg of PEO treatment enhanced the average daily gain of beef cattle compared with the control group (P = 0.032). All PEO treatments reduced the diamine oxidase activity (P = 0.004) and malondialdehyde content (P = 0.008) in serum. In addition, the content of 70 kDa heat shock protein in the 100 mg/kg group was increased, and the activity of glutathione peroxidase and total antioxidant capacity in both 100 mg/kg and 150 mg/kg groups were enhanced compared to the control group (P < 0.05). More importantly, PEO treatment with 50 mg/kg enhanced the mRNA relative expressions of occludin in ruminal epithelia but decreased the mRNA relative expressions of c-Jun N-terminal kinase, P38 mitogen-activated protein kinases, caspase-3, Beclin1 (P < 0.05), and extremely significant declined the mRNA relative expressions of extracellular regulated protein kinases and ubiquitin-binding protein in contrast to the control group (P < 0.01). These findings indicated that dietary PEO supplementation might be favorable to improve growth performance and repairing damaged rumen epithelium of heat-stressed cattle by down-regulating the mitogen-activated protein kinase signaling pathway.

REV-ERBα agonist SR10067 attenuates Th2 cytokine-mediated barrier dysfunction in human bronchial epithelial cells.

Allergens and Th2 cytokines affect the homeostatic environment in the airways, leading to increased mucus production by goblet cells associated with altered adherens junctional complex (AJC) and tight junction (TJ) proteins responsible for maintaining epithelial barrier function. Circadian clock-dependent regulatory mechanisms such as inflammation and epithelial barrier function are gaining more attention due to their therapeutic potential against allergic inflammatory lung diseases. Currently, there are no studies to support whether REV-ERBα activation can attenuate Th2 cytokine-induced epithelial barrier dysfunction in human bronchial epithelial cells. We hypothesized that Th2 cytokine-induced epithelial barrier dysfunction may be protected by activating REV-ERBα. Treatment with Th2 cytokines or HDM significantly reduced the cell impedance, as confirmed by transepithelial electrical resistance (TEER). However, pre-treatment with SR10067 attenuated Th2 cytokine-induced barrier dysfunction, such as decreased permeability, improved TEER, localization of AJC and TJ proteins, and mRNA and protein levels of selected epithelial barrier and circadian clock targets. Overall, we showed for the first time that REV-ERBα activation regulates altered epithelial barrier function that may have direct implications for the treatment of asthma and other allergic diseases.

Human placental mesenchymal stem cells transplantation repairs the alveolar epithelial barrier to alleviate lipopolysaccharides-induced acute lung injury.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are accompanied by high mortality rates and few effective treatments. Transplantation of human placental mesenchymal stem cells (hPMSCs) may attenuate ALI and the mechanism is still unclear. Our study aimed to elucidate the potential protective effect and therapeutic mechanism of hPMSCs against lipopolysaccharide (LPS)-induced ALI, An ALI model was induced by tracheal instillation of LPS into wild-type (WT) and angiotensin-converting enzyme 2 (ACE2) knockout (KO) male mice, followed by injection of hPMSCs by tail vein. Treatment with hPMSCs improved pulmonary histopathological injury, reduced pulmonary injury scores, decreased leukocyte count and protein levels in bronchoalveolar lavage fluid(BALF), protected the damaged alveolar epithelial barrier, and reversed LPS-induced upregulation of pro-inflammatory factors Interleukin-6 (IL-6) and Tumor necrosis factor-α(TNF-α) and downregulation of anti-inflammatory factor Interleukin-6(IL-10) in BALF. Moreover, administration of hPMSCs inhibited Angiotensin (Ang)II activation and promoted the expression levels of ACE2 and Ang (1-7) in ALI mice. Pathological damage, inflammation levels, and disruption of alveolar epithelial barrier in ALI mice were elevated after the deletion of ACE2 gene, and the Renin angiotensin system (RAS) imbalance was exacerbated. The therapeutic effect of hPMSCs was significantly reduced in ACE2 KO mice. Our findings suggest that ACE2 plays a key role in hPMSCs repairing the alveolar epithelial barrier to protect against ALI, laying a new foundation for the clinical treatment of ALI.

Exposure of Colon-Derived Epithelial Monolayers to Fecal Luminal Factors from Patients with Colon Cancer and Ulcerative Colitis Results in Distinct Gene Expression Patterns.

Microbiota and luminal components may affect epithelial integrity and thus participate in the pathophysiology of colon cancer (CC) and inflammatory bowel disease (IBD). Therefore, we aimed to determine the effects of fecal luminal factors derived from patients with CC and ulcerative colitis (UC) on the colonic epithelium using a standardized colon-derived two-dimensional epithelial monolayer. The complex primary human stem cell-derived intestinal epithelium model, termed RepliGut® Planar, was expanded and passaged in a two-dimensional culture which underwent stimulation for 48 h with fecal supernatants (FS) from CC patients (n = 6), UC patients with active disease (n = 6), and healthy subjects (HS) (n = 6). mRNA sequencing of monolayers was performed and cytokine secretion in the basolateral cell culture compartment was measured. The addition of fecal supernatants did not impair the integrity of the colon-derived epithelial monolayer. However, monolayers stimulated with fecal supernatants from CC patients and UC patients presented distinct gene expression patterns. Comparing UC vs. CC, 29 genes were downregulated and 33 genes were upregulated, for CC vs. HS, 17 genes were downregulated and five genes were upregulated, and for UC vs. HS, three genes were downregulated and one gene was upregulated. The addition of FS increased secretion of IL8 with no difference between the study groups. Fecal luminal factors from CC patients and UC patients induce distinct colonic epithelial gene expression patterns, potentially reflecting the disease pathophysiology. The culture of colonic epithelial monolayers with fecal supernatants derived from patients may facilitate the exploration of IBD- and CC-related intestinal microenvironmental and barrier interactions.

Quercetin Alleviates the Progression of Chronic Rhinosinusitis Without Nasal Polyps by Inhibiting Nasal Mucosal Inflammation and Epithelial Apoptosis.

Chronic rhinosinusitis (CRS) is a common chronic inflammatory upper respiratory tract, has a major subtype of CRS without nasal polyps (CRSsNP), constituting a great global health problem. Quercetin exerts the important roles in several inflammatory diseases. However, its function in CRSsNP remains unclear. In this study, quercetin dose-dependently alleviated allergic nasal symptoms of increased frequencies of sneezing and nasal scratching in Staphylococcus aureus-constructed CRSsNP mice. Importantly, quercetin attenuated the histopathological changes of nasal mucosa tissue in model mice, including mucosal thickening, glandular hyperplasia, noticeable mast cells, and inflammatory cell infiltration. Concomitantly, quercetin alleviated the increased mucosal inflammation in CRSsNP mice by suppressing the transcripts and releases of pro-inflammatory IL-1ß, IL-6, and IL-4. Notably, quercetin restrained X-box binding protein 1 (XBP1)-mediated activation of the HIF-1α/wnt-ß-catenin axis in nasal mucosal tissues in CRSsNP model. Intriguingly, intranasal instillation of Lv-XBP1 offset the protective efficacy of quercetin against the progression of CRSsNP by suppressing the production of inflammatory cytokine IL-1ß, IL-6, and IL-4, frequency of sneezing and nasal scratching, and histopathological changes of nasal mucosa tissues. In vitro, higher expression of XBP1 was observed in human nasal epithelial cells (HNECs) of CRSsNP relative to the normal HNECs. Moreover, elevation of XBP1 by Lv-XBP1 treatment suppressed cell proliferation and increased apoptosis of CRSsNP HNECs. Mechanistically, XBP1 overexpression increased the expression of HIF-1α and ß-catenin, indicating the activation of the HIF-1α/wnt-ß-catenin axis. Nevertheless, treatment with quercetin inhibited XBP1-induced cell apoptosis and reversed XBP1-mediated inhibition in cell proliferation in HNECs, as well as the activation of the HIF-1α/wnt-ß-catenin axis. Thus, these findings reveal that quercetin may attenuate the progression of CRSsNP by inhibiting nasal mucosal inflammation and epithelial barrier dysfunction via blocking the XBP1/HIF-1α/wnt-ß-catenin pathway, supporting a promising agent against CRSsNP.

Indole­3­propionic acid alleviates intestinal epithelial cell injury via regulation of the TLR4/NF­κB pathway to improve intestinal barrier function.

Indole­3­propionic acid (IPA), a product of Clostridium sporogenes metabolism, has been shown to improve intestinal barrier function. In the present study, in vitro experiments using NCM460 human colonic epithelial cells were performed to investigate how IPA alleviates lipopolysaccharide (LPS)­induced intestinal epithelial cell injury, with the aim of improving intestinal barrier function. In addition, the underlying mechanism was explored. NCM460 cell viability and apoptosis were measured using the Cell Counting Kit­8 assay and flow cytometry, respectively. The integrity of the intestinal epithelial barrier was evaluated by measuring transepithelial electrical resistance (TEER). The underlying molecular mechanism was explored using western blotting, immunofluorescence staining, a dual luciferase reporter gene assay and quantitative PCR. The results showed that 10 µg/ml LPS induced the most prominent decrease in cell viability after 24 h of treatment. By contrast, IPA effectively inhibited LPS­induced apoptosis in the intestinal epithelial cells. Additionally, >0.5 mM IPA improved intestinal barrier function by increasing TEER and upregulating the expression of tight junction proteins (zonula occludens­1, claudin­1 and occludin). Furthermore, IPA inhibited the release of pro­inflammatory cytokines (IL­1ß, IL­6 and TNF­α) in a dose­dependent manner and this was achieved via regulation of the Toll­like receptor 4 (TLR4)/myeloid differentiation factor 88/NF­κB and TLR4/TRIF/NF­κB pathways. In conclusion, IPA may alleviate LPS­induced inflammatory injury in human colonic epithelial cells. Taken together, these results suggest that IPA may be a potential therapeutic approach for the management of diseases characterized by LPS­induced intestinal epithelial cell injury and intestinal barrier dysfunction.

Lentinan attenuates allergic airway inflammation and epithelial barrier dysfunction in asthma via inhibition of the PI3K/AKT/NF-κB pathway.

BACKGROUND: Allergic asthma has been regarded as an inflammatory disease mediated by type 2 immunity. The treatment of progressive forms of asthma remains unsatisfactory despite substantial progress in drug development. Lentinan (LTN), a specific polysaccharide derived from Lentinus edodes, exhibits anti-inflammatory and immunomodulatory functions. Nevertheless, the effect and underlying mechanisms of Lentinan on asthma remain unclear. PURPOSE: This research investigated the regulatory role of Lentinan on allergic airway inflammation and epithelial barrier dysfunction in HDM (house dust mite)-induced asthma. STUDY DESIGN: HDM-induced C57BL/6 mice received different dosages of Lentinan through intraperitoneal injections, to observe the effect of Lentinan against allergic airway inflammation and epithelial barrier dysfunction in asthma. METHODS: Mice were intranasally administered HDM extract solution on days 0, 1, 2 and on days 8 to 12, establishing the allergic asthma model. On days 8 to 12, mice were intraperitoneally administered varying doses of Lentinan (5/10/20mg/kg) 1h before HDM challenge. On day 14, samples were harvested for analysis. Cell counting, flow cytometry, ELISA, HE and PAS staining, IF staining, western blotting, RT-PCR, and bioinformatic analysis were conducted to delve into the underlying functions and mechanisms of Lentinan in asthma. RESULTS: Our study revealed that the treatment of Lentinan significantly ameliorated allergic airway inflammation and improved epithelial barrier dysfunction in experimental mice. Following Lentinan treatment, there was a significant reduction in eosinophil counts, accompanied by a diminished presence of type 2 cytokines. Reversal of epithelial barrier dysfunction after treatment was also observed. The therapeutic mechanism involved suppression of the PI3K/AKT/ NF-κB pathway. CONCLUSION: Our research illuminated the protective role of Lentinan in allergic airway inflammation and impaired epithelial barrier, suggesting LTN could be an innovative and promising candidate for asthma treatment.

Characterization of non-epithelial cells embedded within the vocal fold epithelial barrier.

The vocal folds vibrate to produce voice, undergoing significant stress due to contact and shearing force. The epithelium operates as the primary protective layer of the tissue against stress and vibratory damage, as well as to provide a barrier against foreign organisms and toxins. Within the vocal fold epithelium, non-epithelial cells were identified that may interrupt the epithelium and compromise the epithelial barrier's protective function. Human vocal fold samples with a variety of pathologies were compared to normal vocal folds. Analysis included the number of cells in the epithelium and epithelial thickness. Vocal fold sections from 10 human tissue samples were assessed via H&E staining and immunofluorescent co-labeling. Three cell populations (vimentin expressing, CD-45 expressing, and cells expressing both) were identified within the epithelium. Statistical analysis revealed that the abnormal samples had a significantly greater number of vimentin-positive cells/area within the epithelium compared to the normal samples. Additionally, normal tissue samples had a significantly greater epithelial depth, suggesting a more robust epithelial barrier compared to tissue with pathology. Knowledge of the function of these cells could lead to a better understanding of how the local immune environment near and within vocal fold epithelium changes in the presence of different pathologies.

Advanced glycation end products (AGEs) impair the intestinal epithelial barrier via STAT3 activation mediated by macrophages.

Advanced glycation end products (AGEs) are a spectrum of complex compounds widely found in processed foods and frequently consumed by humans. AGEs are implicated in impairing the intestinal barrier, but the underlying mechanisms remain unclear. This study investigated the effects of three types of AGEs on gene expression of tight junctions (TJs) in colorectal epithelial HT-29 cells, and observed minimal alterations in TJs expression. Given the important role of subepithelial macrophages in regulating the intestinal barrier, we explored whether AGEs affect the intestinal barrier via the involvement of macrophages. Notably, a significant downregulation of TJs expression was observed when supernatants from AGEs-treated RAW264.7 macrophage cells were transferred to HT-29 cells. Further investigations indicated that AGEs increased IL-6 levels in RAW264.7 cells, subsequently triggering STAT3 activation and suppressing TJs expression in HT-29 cells. The role of STAT3 activation was confirmed by observing enhanced TJs expression in HT-29 cells following pretreatment with an inhibitor of STAT3 activation prior to the transfer of the conditioned medium. These findings demonstrated that AGEs impaired the intestinal barrier via macrophage-mediated STAT3 activation, shedding light on the mechanisms underlying AGEs-induced intestinal barrier injury and related food safety risks.

Modulation of Bronchial Epithelial Barrier Integrity by Low Molecular Weight Components from Birch Pollen.

Pollen, in addition to allergens, comprise low molecular weight components (LMC) smaller than 3 kDa. Emerging evidence indicates the relevance of LMC in allergic immune responses. However, the interaction of birch pollen (BP)-derived LMC and epithelial cells has not been extensively studied. We investigated epithelial barrier modifications induced by exposure to BP LMC, using the human bronchial epithelial cell line 16HBE14o-. Epithelial cell monolayers were apically exposed to the major BP allergen Bet v 1, aqueous BP extract or BP-derived LMC. Barrier integrity after the treatments was monitored by measuring transepithelial electrical resistance at regular intervals and by using the xCELLigence Real-Time Cell Analysis system. The polarized release of cytokines 24 h following treatment was measured using a multiplex immunoassay. Epithelial barrier integrity was significantly enhanced upon exposure to BP LMC. Moreover, BP LMC induced the repair of papain-mediated epithelial barrier damage. The apical release of CCL5 and TNF-α was significantly reduced after exposure to BP LMC, while the basolateral release of IL-6 significantly increased. In conclusion, the results of our study demonstrate that BP-derived LMC modify the physical and immunological properties of bronchial epithelial cells and thus regulate airway epithelial barrier responses.

Nanoparticles and Airway Epithelial Cells: Exploring the Impacts and Methodologies in Toxicity Assessment.

The production of nanoparticles has recently surged due to their varied applications in the biomedical, pharmaceutical, textile, and electronic sectors. However, this rapid increase in nanoparticle manufacturing has raised concerns about environmental pollution, particularly its potential adverse effects on human health. Among the various concerns, inhalation exposure to nanoparticles poses significant risks, especially affecting the respiratory system. Airway epithelial cells play a crucial role as the primary defense against inhaled particulate matter and pathogens. Studies have shown that nanoparticles can disrupt the airway epithelial barrier, triggering inflammatory responses, generating reactive oxygen species, and compromising cell viability. However, our understanding of how different types of nanoparticles specifically impact the airway epithelial barrier remains limited. Both in vitro cell culture and in vivo murine models are commonly utilized to investigate nanoparticle-induced cellular responses and barrier dysfunction. This review discusses the methodologies frequently employed to assess nanoparticle toxicity and barrier disruption. Furthermore, we analyze and compare the distinct effects of various nanoparticle types on the airway epithelial barrier. By elucidating the diverse responses elicited by different nanoparticles, we aim to provide insights that can guide future research endeavors in assessing and mitigating the potential risks associated with nanoparticle exposure.

Lysosomal dysfunction-derived autophagy impairment of gingival epithelial cells in diabetes-associated periodontitis with altered protein acetylation.

Diabetes-associated periodontitis (DP) presents severe inflammation and resistance to periodontal conventional treatment, presenting a significant challenge in clinical management. In this study, we investigated the underlying mechanism driving the hyperinflammatory response in gingival epithelial cells (GECs) of DP patients. Our findings indicate that lysosomal dysfunction under high glucose conditions leads to the blockage of autophagy flux, exacerbating inflammatory response in GECs. Single-cell RNA sequencing and immunohistochemistry analyses of clinical gingival epithelia revealed dysregulation in the lysosome pathway characterized by reduced levels of lysosome-associated membrane glycoprotein 2 (LAMP2) and V-type proton ATPase 16 kDa proteolipid subunit c (ATP6V0C) in subjects with DP. In vitro stimulation of human gingival epithelial cells (HGECs) with a hyperglycemic microenvironment showed elevated release of proinflammatory cytokines, compromised lysosomal acidity and blocked autophagy. Moreover, HGECs with deficiency in ATP6V0C demonstrated impaired autophagy and heightened inflammatory response, mirroring the effects of high glucose stimulation. Proteomic analysis of acetylation modifications identified altered acetylation levels in 28 autophagy-lysosome pathway-related proteins and 37 sites in HGECs subjected to high glucose stimulation or siATP6V0C. Overall, our finding highlights the pivotal role of lysosome impairment in autophagy obstruction in DP and suggests a potential impact of altered acetylation of relevant proteins on the interplay between lysosome dysfunction and autophagy blockage. These insights may pave the way for the development of effective therapeutic strategies against DP.

Dragon's blood attenuates LPS-induced intestinal epithelial barrier dysfunction via upregulation of FAK-DOCK180-Rac1-WAVE2-Arp3 and downregulation of TLR4/NF-κB signaling pathways.

Inflammation-induced intestinal epithelial barrier (IEB) dysfunction is one of the important reasons for the occurrence and development of intestinal inflammatory-related diseases, including ulcerative colitis (UC), Crohn's disease and necrotizing enterocolitis (NEC). Dragon's blood (DB) is a traditional Chinese medicine and has been clinically used to treat UC. However, the protective mechanism of DB on intestinal inflammatory-related diseases has still not been elucidated. The present study aimed to explore the protection mechanism of DB on IEB dysfunction in rat ileum and human colorectal adenocarcinoma cells (Caco-2)/human umbilical vein endothelial cells (HUVECs) coculture system induced by lipopolysaccharide (LPS). DB could ameliorate rat ileum mucosa morphological injury, reduce the accumulation of lipid-peroxidation products and increase the expression of junction proteins. DB also alleviated LPS-induced Caco-2 cells barrier integrity destruction in Caco-2/ HUVECs coculture system, leading to increased trans-endothelial electrical resistance (TEER), reduced cell permeability, and upregulation of expressions of F-actin and junction proteins. DB contributed to the assembly of actin cytoskeleton by upregulating the FAK-DOCK180-Rac1-WAVE2-Arp3 pathway and contributed to the formation of intercellular junctions by downregulating TLR4-MyD88-NF-κB pathway, thus reversing LPS-induced IEB dysfunction. These novel findings illustrated the potential protective mechanism of DB on intestinal inflammatory-related diseases and might be useful for further clinical application of DB.

Coactosin-like protein 1 regulates integrity and repair of model intestinal epithelial barriers via actin binding dependent and independent mechanisms.

The actin cytoskeleton regulates the integrity and repair of epithelial barriers by mediating the assembly of tight junctions (TJs), and adherens junctions (AJs), and driving epithelial wound healing. Actin filaments undergo a constant turnover guided by numerous actin-binding proteins, however, the roles of actin filament dynamics in regulating intestinal epithelial barrier integrity and repair remain poorly understood. Coactosin-like protein 1 (COTL1) is a member of the ADF/cofilin homology domain protein superfamily that binds and stabilizes actin filaments. COTL1 is essential for neuronal and cancer cell migration, however, its functions in epithelia remain unknown. The goal of this study is to investigate the roles of COTL1 in regulating the structure, permeability, and repair of the epithelial barrier in human intestinal epithelial cells (IEC). COTL1 was found to be enriched at apical junctions in polarized IEC monolayers in vitro. The knockdown of COTL1 in IEC significantly increased paracellular permeability, impaired the steady state TJ and AJ integrity, and attenuated junctional reassembly in a calcium-switch model. Consistently, downregulation of COTL1 expression in Drosophila melanogaster increased gut permeability. Loss of COTL1 attenuated collective IEC migration and decreased cell-matrix attachment. The observed junctional abnormalities in COTL1-depleted IEC were accompanied by the impaired assembly of the cortical actomyosin cytoskeleton. Overexpression of either wild-type COTL1 or its actin-binding deficient mutant tightened the paracellular barrier and activated junction-associated myosin II. Furthermore, the actin-uncoupled COTL1 mutant inhibited epithelial migration and matrix attachment. These findings highlight COTL1 as a novel regulator of the intestinal epithelial barrier integrity and repair.

Restoration of corneal epithelial barrier function: A possible target for corneal neovascularization.

Corneal neovascularization (CoNV) is the second leading common cause of vision impairment worldwide and is a blinding pathological alteration brought on by ocular trauma, infection, and other factors. There are some limitations in the treatment of CoNV, hence it's critical to look into novel therapeutic targets. The corneal epithelial barrier, which is the initial barrier of the ocular surface, is an important structure that shields the eye from changes in the internal environment or invasion by the external environment. This study sought to collate evidence on the regulation of corneal epithelial barrier injury on the activation of vascular endothelial cells (VECs), basement membrane (BM) degradation, differentiation, migration, and proliferation of VECs, vascular maturation and stability, and other key processes in CoNV, so as to provide a novel concept for CoNV therapy targeting corneal epithelial barrier repair.

An iPSC-derived small intestine-on-chip with self-organizing epithelial, mesenchymal, and neural cells.

Human induced pluripotent stem cell (hiPSC)-derived intestinal organoids are valuable tools for researching developmental biology and personalized therapies, but their closed topology and relative immature state limit applications. Here, we use organ-on-chip technology to develop a hiPSC-derived intestinal barrier with apical and basolateral access in a more physiological in vitro microenvironment. To replicate growth factor gradients along the crypt-villus axis, we locally expose the cells to expansion and differentiation media. In these conditions, intestinal epithelial cells self-organize into villus-like folds with physiological barrier integrity, and myofibroblasts and neurons emerge and form a subepithelial tissue in the bottom channel. The growth factor gradients efficiently balance dividing and mature cell types and induce an intestinal epithelial composition, including absorptive and secretory lineages, resembling the composition of the human small intestine. This well-characterized hiPSC-derived intestine-on-chip system can facilitate personalized studies on physiological processes and therapy development in the human small intestine.

IL-37 protects against house dust mite-induced airway inflammation and airway epithelial barrier dysfunction via inhibiting store-operated calcium entry.

BACKGROUND: Airway epithelial barrier dysfunction has been proved to contribute to the development of type 2 inflammation of asthma. Interleukin (IL)-37 is a negative regulator of immune responses and allergic airway inflammation. However, whether IL-37 has any effect on airway epithelial barrier has been unknown. METHODS: We evaluated the role of IL-37 in both mouse model and cultured 16HBE cells. Histology and ELISA assays were used to evaluate airway inflammation. FITC-dextran permeability assay was used to evaluate the airway epithelial barrier function. Immunofluorescence, western blot and quantitative Real-Time PCR (RT-PCR) were used to evaluate the distribution and expression of tight junction proteins. RT-PCR and Ca2+ fluorescence measurement were used to evaluate the mRNA expression and activity of store-operated calcium entry (SOCE). RESULTS: IL-37 inhibited house dust mite (HDM)-induced airway inflammation and decreased the levels of IgE in serum and type 2 cytokines in bronchoalveolar lavage fluid (BALF) compared to asthmatic mice. IL-37 protected against HDM-induced airway epithelial barrier dysfunction, including reduced leakage of FITC-dextran, enhanced expression of TJ proteins, and restored the membrane distribution of TJ proteins. Moreover, IL-37 decreased the level of IL-33 in the BALF of asthmatic mice and the supernatants of HDM-treated 16HBE cells. IL-37 decreased the peak level of Ca2+ fluorescence induced by thapsigargin and HDM, and inhibited the mRNA expression of Orai1, suggesting an inhibiting effect of IL-37 on SOCE in airway epithelial cells. CONCLUSION: IL-37 plays a protective role in airway inflammation and HDM-induced airway epithelial barrier dysfunction by inhibiting SOCE.

Bacteriocins attenuate Listeria monocytogenes-induced intestinal barrier dysfunction and inflammatory response.

Bacteriocins have the potential to effectively improve food-borne infections or gastrointestinal diseases and hold promise as viable alternatives to antibiotics. This study aimed to explore the antibacterial activity of three bacteriocins (nisin, enterocin Gr17, and plantaricin RX-8) and their ability to attenuate intestinal barrier dysfunction and inflammatory responses induced by Listeria monocytogenes, respectively. Bacteriocins have shown excellent antibacterial activity against L. monocytogenes without causing any cytotoxicity. Bacteriocins inhibited the adhesion and invasion of L. monocytogenes on Caco-2 cells, lactate dehydrogenase (LDH), trans-epithelial electrical resistance (TEER), and cell migration showed that bacteriocin improved the permeability of Caco-2 cells. These results were attributed to the promotion of tight junction proteins (TJP) assembly, specifically zonula occludens-1 (ZO-1), occludin, and claudin-1. Furthermore, bacteriocins could alleviate inflammation by inhibiting the mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) pathways and reducing the secretion of interleukin-6 (IL-6), interleukin-1 ß (IL-1ß) and tumor necrosis factor α (TNF-α). Among three bacteriocins, plantaricin RX-8 showed the best antibacterial activity against L. monocytogenes and the most pronounced protective effect on the intestinal barrier due to its unique structure. Based on our findings, we hypothesized that bacteriocins may inhibit the adhesion and invasion of L. monocytogenes by competing adhesion sites. Moreover, they may further enhance intestinal barrier function by inhibiting the expression of L. monocytogenes virulence factors, increasing the expression of TJP and decreasing the secretion of inflammatory factors. Therefore, bacteriocins will hopefully be an effective alternative to antibiotics, and this study provides valuable insights into food safety concerns. KEY POINTS: • Bacteriocins show excellent antibacterial activity against L. monocytogenes • Bacteriocins improve intestinal barrier damage and inflammatory response • Plantaricin RX-8 has the best protective effect on Caco-2 cells damage.

Comprehensive analysis of resilience of human airway epithelial barrier against short-term PM2.5 inorganic dust exposure using in vitro microfluidic chip and ex vivo human airway models.

BACKGROUND AND OBJECTIVE: The updated World Health Organization (WHO) air quality guideline recommends an annual mean concentration of fine particulate matter (PM2.5) not exceeding 5 or 15 µg/m3 in the short-term (24 h) for no more than 3-4 days annually. However, more than 90% of the global population is currently exposed to daily concentrations surpassing these limits, especially during extreme weather conditions and due to transboundary dust transport influenced by climate change. Herein, the effect of respirable

Time-dependent effects of tumor necrosis factor α on Ca2+-dependent secretion in murine small intestinal organoids.

Background: Intestinal organoids are stem cell-derived, 3D "mini-guts" with similar functions as the native intestinal epithelium such as electrolyte transport or establishment of an epithelial barrier. During intestinal inflammation, epithelial functions are dysregulated by proinflammatory cytokines like tumor necrosis factor α (TNFα) and other messengers from the immune system resulting in a loss of electrolytes and water due to an impaired epithelial barrier and higher net secretion. Methods: A murine small intestinal organoid model was established to study (long-term) effects of TNFα on the intestinal epithelium in vitro using live imaging, immunohistochemical staining and qPCR. Results: TNFα induced apoptosis in intestinal organoids as indicated by an increased number of cells with immunoreactivity for cleaved caspase 3. Furthermore, TNFα exposure led to swelling of the organoids which was inhibited by bumetanide and was concomitant with an upregulation of the bumetanide-sensitive Na+-K+-2Cl- symporter 1 (NKCC1) as shown by qPCR. Fura-2 imaging experiments revealed time-dependent changes in Ca2+ signaling consisting of a rise in the basal cytosolic Ca2+ concentration at day 1 and an increase of the carbachol-induced Ca2+ response after 3 days TNFα exposure. This was prevented by preincubation with La3+, an inhibitor of non-selective cation channels, or by using a Ca2+-free buffer indicating an enhancement of the Ca2+ influx from the extracellular side by the cytokine. No significant changes in cDNA levels of epithelial barrier proteins could be observed in the presence of TNFα. Conclusion: Intestinal organoids are a useful tool to study the mechanism underlying the TNFα-induced secretion on enterocytes such as the regulation of NKCC1 expression or the modulation of cellular Ca2+ signaling.