Junctions Of Epithelial Cells Research Articles

Could E-cadherin overexpression promote epithelial differentiation of human adipose-derived stem cells by mediating mesenchymal-to-epithelial transition?

After skin injury, one of the major components of the healing process is wound re-epithelialization, which is driven by residual epithelial stem cells from skin appendages. However, the re-epithelialization process is vulnerable to severe trauma due to irreversible damage to the skin appendages. Engineering a functionalized epithelium using pluripotent stem cells from other tissue sources could provide an extraordinary skin substitute that could rapidly close a wound while reducing secondary damage to the skin. Human adipose-derived stem cells (hASCs) are widely distributed in the subcutaneous tissue and can theoretically differentiate into epithelial lineage cells. However, a definite and effective induction protocol has not yet been developed, and thus epithelial phenotype establishment in hASCs remains difficult. In particular, hASCs are unable to produce the key trigger protein E-cadherin, which is required for epithelial transition; therefore, we hypothesized that the stable overexpression of E-cadherin in hASCs could induce the epithelial phenotype in hASCs via the mesenchymal-to-epithelial transition (MET), making hASCs qualified candidates for wound re-epithelialization and skin tissue engineering. The achievement of the N- to E-cadherin switch in hASCs might induce epithelialized characteristics (such as epithelial cell junctions, apicobasal polarity, cytokeratin production, and loss of original mesenchymal features) in hASCs, which exhibit functionality similar to that of keratinocytes. Combining epithelialized hASCs with inductive scaffolds could allow them to be applied in epithelial tissue engineering, thus providing a sufficient source of skin substitutes to treat refractory wounds. Moreover, epithelialized hASCs could be the subject of future research exploring the in-depth molecular biological mechanism of MET mediated by E-cadherin.

Expression of concern: Sodium butyrate ameliorated diabetic nephropathy-associated tubulointerstitial inflammation by modulating tight junction of renal tubular epithelial cells

Expression of concern for ‘Sodium butyrate ameliorated diabetic nephropathy-associated tubulointerstitial inflammation by modulating tight junction of renal tubular epithelial cells’ by Tingting Yang et al., Food Funct., 2022, accepted manuscript, https://doi.org/10.1039/D2FO00940D.

Effect of microand nanoplastics on the gastrointestinal mucosa and intestinal microbiome

Worldwide production and use of the polymers has led to intensive environmental pollution with micro- and nanoplastics (MP and NP). Accumulating in ecosystems, MP are transmitted through food chains and enter the human body. The associated health risks are of grave concern and require assessment. The main entry gate for MP/NP supplied with food is the gastrointestinal tract (GIT). Despite the well-established concept of MP/NP toxicity, information about their actual effects on the GIT is contradictory. The aim of the research was to establish the nature and mechanisms of NPs and MPs action on the gastrointestinal mucosa and intestinal microbiome, basing on the literature data. Material and methods. The review was compiled after selecting of 90 documents from major databases including Web of Science, PubMed, Scopus, Elsevier, Springer and Google Scholar (up to March 2023). Results. In animal studies and in vitro models, it was shown that MP/NP affect mucus secretion, its rheological characteristics, and can cause an increase in the permeability of tight junctions of epithelial cells by reducing the expression of zonula occludens protein 1 (ZO-1), occludin and claudin-1, which promotes the penetration of MP through the intestinal wall. Various adsorption layers (coronas) formed on the surface of MPs both abiotically and during transit through the GIT can lead to both increased and reduced toxicity of MPs. Biofilms formed on MP/NP surface create favorable conditions for the activity of pathogenic bacteria and horizontal gene exchange between the components of the biofilm and the intestinal microbiome. Animal experiments have shown an unfavorable effect of MP/NP on the intestinal microbiota and its key metabolites, contributing to the development of dysbiosis. Conclusion. Most data on the effect of MP on the GIT have been obtained using a model object - polystyrene microspheres, which are rarely found in practice. A frequent limitation of the in vitro studies is the discrepancy between used doses (concentrations) of MP and those that may occur when MP are consumed with food. Data on the potential impact of MP/NP on the GIT protective barrier and intestinal microbiota obtained under various experimental conditions are contradictory. Thus, evidence of the impact of MP/NP on the GIT and intestinal microbiota of humans needs further confirmation, which will allow us to move on to the development of a set of measures that can reduce the risks of MP exposure to human health.

Cell Morphology-Based Screening Identified Vitetrifolin D from <i>Vitex Rotundifolia</i> as an Inhibitor of Phorbol Ester–Induced Downregulation of E-Cadherin in HHUA Endometrial Cells

The epithelial–mesenchymal transition (EMT) of endometrial cells contributes to the development of endometrial cancer, endometriosis, and adenomyosis. We have recently reported that 12-O-Tetradecanoylphorbol 13-acetate (TPA), a protein kinase C activator, induces EMT in HHUA endometrial cells cultured on collagen type I gels. HHUA cells showed an obvious morphological change from spheroids to scattered spindle cells during the TPA-induced EMT. In this study, we searched for inhibitors of the TPA-induced morphological change, and isolated vitetrifolin D from Vitex rotundifolia leaves. Vitetrifolin D suppressed the TPA-induced downregulation of E-cadherin, a major component of the epithelial adherens junction. Since vitetrifolin D showed a modest cytotoxicity at the concentration required to inhibit E-cadherin downregulation, it would not be suitable as a drug to treat endometrial disorders. However, our cell morphology-based screening could contribute to the discovery of new compounds that inhibit the loss of epithelial cell junctions.

Protective effects of inhalation of essential oils from Mentha piperita leaf on tight junctions and inflammation in allergic rhinitis.

Allergic rhinitis is one of the most common diseases, which is caused by IgE-mediated reactions to inhaled allergens. Essential oils from the Mentha piperita leaf (EOM) are known to be effective for various diseases, such as respiratory diseases. However, the effect of inhalation of EOM on tight junctions and inflammation related to allergic rhinitis is not yet known. The purpose of this research was to explain the effects of the inhalation of EOM on tight junctions and inflammation of allergic rhinitis through network pharmacology and an experimental study. For that purpose, a pharmacology network analysis was conducted comprising major components of EOM. Based on the network pharmacology prediction results, we evaluated the effect of EOM on histological changes in mice with ovalbumin and PM10-induced allergic rhinitis. Allergic symptoms, infiltration of inflammatory cells, and regulation of ZO-1 were investigated in mice with allergic rhinitis. Other allergic parameters were also analyzed by reverse transcription polymerase chain reaction and western blot in nasal epithelial cells. In the network analysis, the effects of EOM were closely related to tight junctions and inflammation in allergic rhinitis. Consistent with the results from the network analysis, EOM significantly decreased epithelial thickness, mast cell degranulation, goblet cell secretion, and the infiltration of inflammatory cells in nasal tissue. EOM also regulated the MAPK-NF-κB signaling pathway, which was related to tight junctions in nasal epithelial cells. This research confirmed that inhalation of EOM effectively restores tight junctions and suppresses inflammation in the allergic rhinitis model. These results reveal that EOM has a therapeutic mechanism to treat allergic rhinitis.

Epididymal epithelial degeneration and lipid metabolism impairment account for male infertility in occludin knockout mice.

Occludin (OCLN) is a tight junction protein and Ocln deletion mutation causes male infertility in mice. However, the role of OCLN in male reproductive system remains unknown. In this study, we used an interdisciplinary approach to elucidate the underlying mechanism of male infertility in related to OCLN function, including Ocln knockout mice as well as a combined omics analysis and immunofluorescent labelling. Our results showed that the epididymis of Ocln-null mice displayed a phenomenon resembling epididymal sperm granuloma, which occurred especially in the junctional region between caput and corpus epididymidis. Sperm motility and fertilisation capacity were also impaired in these Ocln-null mice, accompanied by enlarged tubules in the proximal regions and degeneration in the distal regions of epididymis. Cellular localization analysis showed that OCLN immunofluorescence was enriched only in the apical junction of epithelial principal cells in the proximal regions of epididymis. Integrative omics analysis revealed the downregulation of gene clusters enriched in acid secretion and fatty acid metabolism in the Ocln-null epididymis, especially the enzymes related to the unsaturated arachidonic acid pathway. The number of proton-pump V-ATPase-expression clear cells, a key player of luminal acidification in the epididymis, declined drastically from prepubertal age before sperm arrival but not in the early postnatal age. This was accompanied by programmed cell death of clear cells and increased pH in the epididymal fluid of OCLN-deficient mice. The lipidomics results showed significantly increased levels of specific DAGs conjugated to unsaturated fatty acids in the Ocln-mutant. Immunofluorescent labelling showed that the arachidonic acid converting enzyme PTGDS and phospholipase PLA2g12a were prominently altered in the principal cells and luminal contents of the Ocln-mutant epididymis. Whereas the carboxylate ester lipase CES1, originally enriched in the WT basal cells, was found upregulated in the Ocln-mutant principal cells. Overall, this study demonstrates that OCLN is essential for maintaining caput-to-corpus epithelial integrity, survival of acid-secreting clear cells, and unsaturated fatty acid catabolism in the mouse epididymis, thereby ensuring sperm maturation and male fertility.

Airway Epithelial Cell Junctions as Targets for Pathogens and Antimicrobial Therapy.

Intercellular contacts between epithelial cells are established and maintained by the apical junctional complexes (AJCs). AJCs conserve cell polarity and build epithelial barriers to pathogens, inhaled allergens, and environmental particles in the respiratory tract. AJCs consist of tight junctions (TJs) and adherens junctions (AJs), which play a key role in maintaining the integrity of the airway barrier. Emerging evidence has shown that different microorganisms cause airway barrier dysfunction by targeting TJ and AJ proteins. This review discusses the pathophysiologic mechanisms by which several microorganisms (bacteria and viruses) lead to the disruption of AJCs in airway epithelial cells. We present recent progress in understanding signaling pathways involved in the formation and regulation of cell junctions. We also summarize the potential chemical inhibitors and pharmacological approaches to restore the integrity of the airway epithelial barrier. Understanding the AJCs-pathogen interactions and mechanisms by which microorganisms target the AJC and impair barrier function may further help design therapeutic innovations to treat these infections.

Pine Pollen Polysaccharides' and Sulfated Polysaccharides' Effects on UC Mice through Modulation of Cell Tight Junctions and RIPK3-Dependent Necroptosis Pathways.

The purpose of this study is to explore the effects of pine pollen polysaccharides and sulfated polysaccharides on mice with ulcerative colitis and whether they could protect mice from inflammation by regulating the tight junctions of colonic epithelial cells and regulating the RIPK3-dependent necroptosis pathways. Pine pollen polysaccharides were prepared by water boiling and ethanol precipitation. After deproteinedization with trichloroacetic acid, the UV spectrum showed that there were no proteins. One polysaccharide component (PPM60-III) was made by gel filtration chromatography, and then sulfated polysaccharide (SPPM60-III) was derived using the chlorosulfonic acid-pyridine method. After treatment with PPM60-III and SPPM60-III, the body weight of mice with ulcerative colitis induced by dextran sodium sulfate increased, the DAI score decreased, the levels of pro-inflammatory factors and inflammation-related enzymes decreased, and the level of anti-inflammatory factors increased. In addition, after treatment, the expressions levels of tight junction proteins increased, the expressions levels of key proteins of programmed necroptosis decreased, while the level of Caspase-8 increased. The results indicated that pine pollen polysaccharides and sulfated polysaccharides have a certain therapeutic effect on UC mice, and the therapeutic effect may be achieved by regulating the tight junction of colonic epithelial cells and regulating the RIPK3-dependent necroptosis pathways.

The role of systemic dehydration in vocal fold healing: Preliminary findings.

Systemic dehydration negatively alters the expression of vocal fold inflammatory and cell junction markers. These biological changes can have downstream effects on the healing processes of injured vocal folds. In the dermis, reduced hydration prolongs inflammation and delays healing. It is unknown whether this biological effect is observed in vocal fold tissue. To investigate the effects of systemic dehydration on vocal fold healing outcomes following acute, bilateral vocal fold injury in a rodent model. Eighteen systemic dehydrated and 18 euhydrated adult male Sprague Dawley rats experienced bilateral vocal fold injuries or no injury (N= 9/group). Vocal fold gene expression levels of inflammatory mediators and epithelial cell junction markers were measured 24 h post-injury. Pro-inflammatory gene markers (IL-1β; TNF-α) were differentially expressed in response to systemic dehydration with vocal fold injury compared to non-injury. Epithelial cell junction markers (Cadherin-3, Desmoglein-1) also exhibited divergent trends following systemic dehydration, but these data were not statistically significant. Systemic dehydration may affect cellular vocal fold healing processes within 24 h. These findings lay the groundwork for further investigation of how hydration status can affect vocal fold tissue recovery and influence clinical care.

Autonomous Untethered Microinjectors for Gastrointestinal Delivery of Insulin.

The delivery of macromolecular drugs via the gastrointestinal (GI) tract is challenging as these drugs display low stability as well as poor absorption across the intestinal epithelium. While permeation-enhancing drug delivery methods can increase the bioavailability of low molecular weight drugs, the effective delivery of high molecular weight drugs across the tight epithelial cell junctions remains a formidable challenge. Here, we describe autonomous microinjectors that are deployed in the GI tract, then efficiently penetrate the GI mucosa to deliver a macromolecular drug, insulin, to the systemic circulation. We performed in vitro studies to characterize insulin release and assess the penetration capability of microinjectors and we measured the in vivo release of insulin in live rats. We found that the microinjectors administered within the luminal GI tract could deliver insulin transmucosally to the systemic circulation at levels similar to those with intravenously administered insulin. Due to their small size, tunability in sizing and dosing, wafer-scale fabrication, and parallel, autonomous operation, we anticipate that these microinjectors will significantly advance drug delivery across the GI tract mucosa to the systemic circulation in a safe manner.

Comparative study of two re-embedding methods on the ultrastructure of corneal tissue

PurposeTo expand the routine of pathological diagnostics of surgical keratoplasty specimens via transmission electron microscopy. The target was to identify the best re-embedding method for optimal structural preservation of formalin fixed paraffin embedded (FFPE) corneal tissue re-embedded into resin for ultrastructural analysis. Basic proceduresBovine FFPE corneal tissue was re-embedded into resin with either a rapid osmium-free four-hour-method or a four-day-routine-method known from nephropathology, compared with primary resin embedded bovine corneal tissue. The analysis involved the ultrastructure of cytoplasm, the intercellular interfaces of superficial epithelial cells, deepest basal epithelial cells and corneal endothelial cells, cell matrix interfaces, Bowman layer, corneal stroma, its microfibril bundles and Descemet membrane. Main findingsThe main observation was the equally reduced preservation status of re-embedded FFPE corneal tissue independent of the used re-embedding method. This extends to the intercellular contacts of superficial epithelial cells and the apical tight junctions of corneal endothelial cells. Hemidesmosomal cell matrix contacts showed less demarcation in re-embedded specimens. Cell matrix interfaces of Bowman layer and Descemet membrane were more clearly bordered in primary resin embedded than re-embedded tissue. In contrast, gap junctions in re-embedded tissue were detected in deepest basal epithelial cells and corneal endothelial cells with comparable preservation to primary resin embedding. Bowman layer, corneal stromal extracellular matrix, its microfibril bundles and Descemet membrane showed equal ultrastructural preservation in all evaluated methods. Principal conclusionCorneal tissue can be successfully analysed with transmission electron microscopy after a rapid osmium-free four hour re-embedding procedure from FFPE material. A comparable morphology with primary resin embedded material can be obtained for gap junctions of deepest basal epithelial cells and corneal endothelial cells, further for Bowman layer, corneal stromal extracellular matrix, its microfibril bundles and Descemet membrane.

Immunoexpression of claudin-4 and correlation with estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2-neu in breast cancer.

Claudins are important transmembrane proteins in tight junction. The role of intercellular tight junctions in breast epithelial cells is traditionally thought to be in maintaining polarity and barrier function. However, claudin-4, a tight junction protein, is overexpressed in breast tumor cells compared to normal epithelial cells, which generally corresponds to loss in polarity and can provide valuable information about biology of the tumor. A prospective clinical study was conducted to assess the expression claudin-4 in patients with breast cancer and its correlation with hormone receptors - estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2)-neu. The study included 102 biopsy-proven breast carcinoma patients. The biopsy samples were evaluated immunohistochemistry for expression of ER, PR, HER2-neu, and claudin-4. The expression of claudin-4 was correlated with ER, PR, and HER2-neu. In the study, we found that out of 26 cases of high claudin-4, 25 cases (96.15%) were ER negative and P < 0.001, which was significant. Similar results were found with PR-negative cases. Whereas, out of 76 cases with low claudin-4, 54 cases (71.05%) were HER2-neu negative and P = 0.022, which was significant. Claqudin-4 expression has a negative correlation with ER and PR and has a positive correlation with HER2-neu. Hence, it can be effectively utilized as a prognostic and therapeutic marker in breast cancer in the future.

Perfluorooctane Sulfonic Acid Disrupts Protective Tight Junction Proteins via Protein Kinase D in Airway Epithelial Cells.

Perfluorooctane sulfonic acid (PFOS) is a long chain per- and polyfluoroalklyl substance (PFAS) that has been used in aqueous film-forming foams. Emerging epidemiological evidence indicates that PFOS may be associated with chronic lung diseases such as asthma and analysis of human tissues demonstrates that the lungs carry a significant body burden of PFOS. Deficits in barrier function are a major risk factor for asthma. Thus, we hypothesized that PFOS exposure will lead to impaired epithelial barrier function through dysregulated tight junctions. Hence, we assessed the impact of PFOS on epithelial barrier integrity. Bronchial epithelial cells (16HBE) were grown on collagen-coated transwells and treated to 5-25 μM PFOS, and assessed for changes in barrier function and tight junction proteins. Rescue experiments were performed using the protein kinase D (PKD) inhibitor, CID755673. PFOS treatment reduced transepithelial electrical resistance (TEER) and increased 4 kDa FITC-dextran flux. Additionally, PFOS significantly decreased protein levels and the tight junction organization rate of occludin and zonula occludens 1. Increased phosphorylation (Ser744/Ser748) of PKD was observed 3 h following PFOS treatment. Pretreatment with the PKD inhibitor attenuated PFOS-mediated changes in TEER and FITC-dextran flux and restored occludin protein levels. In conclusion, PFOS causes loss of airway barrier integrity and the disruption of tight junctions in bronchial epithelial cells, which was partly attenuated through the inhibition of PKD. These findings demonstrate that PFOS is capable of disrupting airway barrier function, a potentially driving factor underlying associations between PFOS and respiratory diseases such as asthma.

Decreased junctional adhesion molecule 3 expression induces reactive oxygen species production and apoptosis in trophoblasts†.

Junctional adhesion molecule 3 (JAM3) is involved in epithelial cell junction, cell polarity, and motility. The molecular mechanisms underlying the role of JAM3 in placental dysfunction remain unclear. We hypothesized that JAM3 expression regulates trophoblast fusion, differentiation, proliferation, and apoptosis. Our results revealed that JAM3 was expressed in the cytotrophoblasts and syncytiotrophoblasts of first-trimester and term placental villi. JAM3 expression in cell-cell junctions decreased with the formation of syncytiotrophoblasts. Using trophoblasts as an in vitro model, we observed that forskolin and JAM3 knockdown significantly reduced JAM3 expression and increased syncytium formation. JAM3 knockdown additionally inhibited trophoblast proliferation and increased the number of trophoblasts in the sub-G1 and G2/M phases, indicating cell-cycle disturbance and apoptosis. Cell-cycle arrest was associated with the engagement of checkpoint kinase 2-cell division cycle 25C-cyclin-dependent kinase 1/cyclin B1 signaling. Increased expression of BIM, NOXA, XAF1, cytochrome c, and cleaved caspase-3 further indicated trophoblast apoptosis. Overexpression of JAM3 or recombinant JAM3 protein enhanced trophoblast adhesion and migration, which were inhibited by JAM3 knockdown. JAM3 knockdown induced reactive oxygen species and syncytin 2 expression in trophoblasts. Furthermore, H2O2-induced oxidative stress reduced JAM3 expression in trophoblasts and cell culture supernatants. H2O2 simultaneously induced trophoblast apoptosis. JAM3 expression was significantly decreased in the plasmas and placentas of patients with early-onset severe preeclampsia. Thus, our results show that JAM3 may not only be a structural component of trophoblast cell junctions but also regulates trophoblast fusion, differentiation, proliferation, apoptosis, and motility. Dysregulated trophoblast JAM3 expression is crucial in preeclampsia development.

Vinegar reduced renal calcium oxalate stones by regulating acetate metabolism in gut microbiota and crystal adhesion in rats.

Urolithiasis is a common urologic disease. Higher consumption of vinegar was associated with a lower risk of urolithiasis. Recent studies reported that disorder of gut microbiota and injury of the tight junction of renal tubular epithelial cells were associated with the formation of renal calcium oxalate (CaOx) stones. We aimed to explore the mechanism of vinegar reduced renal CaOx stone formation by regulating gut microbiota and the tight junction of renal tubular epithelial cells. Thirty Sprague-Dawley rats were randomly allocated to control group, model group and vinegar group. Rats in control group got 2ml/kg of sterile water by gavage. Model group rats were additionally supplied with drinking water with 1% (v/v) ethylene glycol (EG) every day. Rats in vinegar group had 1% (v/v) EG in drinking water and were gavaged with 2ml/kg of vinegar (5% acetate) every day. Vinegar reduced renal CaOx crystals and urinary oxalate. Vinegar increased the relative abundances of Ruminococcus gauvreauii, Ruminococcus torques, Ruminococcus-2, Moryella, Enterococcus, Alistipes, and Parabacteroides in the gut microbiota. Blood acetate increased in vinegar group. The renal tight junction occludin protein decreased in the model group and increased in the vinegar group. Studies in vitro verified that acetate could reverse the decline in occludin expression induced by CaOx crystals and inhibit CaOx crystal adhesion to cells. Vinegar reduced renal CaOx stones by regulating gut microbiota and increasing blood acetate to restore renal tight junction and reduce CaOx crystal adhesion.

Effects of hypoxia on respiratory diseases: perspective view of epithelial ion transport.

The balance of gas exchange and lung ventilation is essential for the maintenance of body homeostasis. There are many ion channels and transporters in respiratory epithelial cells, including epithelial sodium channel, Na,K-ATPase, cystic fibrosis transmembrane conductance regulator, and some transporters. These ion channels/transporters maintain the capacity of liquid layer on the surface of respiratory epithelial cells and provide an immune barrier for the respiratory system to clear off foreign pathogens. However, in some harmful external environments and/or pathological conditions, the respiratory epithelium is prone to hypoxia, which would destroy the ion transport function of the epithelium and unbalance the homeostasis of internal environment, triggering a series of pathological reactions. Many respiratory diseases associated with hypoxia manifest an increased expression of hypoxia-inducible factor-1, which mediates the integrity of the epithelial barrier and affects epithelial ion transport function. It is important to study the relationship between hypoxia and ion transport function, whereas the mechanism of hypoxia-induced ion transport dysfunction in respiratory diseases is not clear. This review focuses on the relationship between hypoxia and respiratory diseases, as well as dysfunction of ion transport and tight junctions in respiratory epithelial cells under hypoxia.

Nanoarchitecture and molecular interactions of epithelial cell junction proteins revealed by super-resolution microscopy.

Epithelial cells are polarized with defined apical tight junctions (TJs), lateral adherens junctions (AJs), and basal integrin-matrix interactions. However, it is increasingly recognized that resident cell junction proteins can be found in varying locations and with previously unrecognized functions. Our study here presents the nanoarchitecture and nanocolocalization of cell junction proteins in culture and tissue by stochastic optical reconstruction microscopy (STORM). The Z-axial view of noncancerous MDCK-II and PZ-HPV-7 cell-cell junctions resolved β-catenin and p120ctn localizations to TJs and AJs, with p120ctn apical to β-catenin and colocalizing with TJ protein claudin-7. More basally, p120ctn and β-catenin become colocalized. This topography was lost in isogenic Ras-transformed MDCK cells and cancerous PC3 cells, where p120ctn becomes basally localized in relation to β-catenin. Claudin-7 gene conditional knockout (cKO) in mice also have altered polarity of p120ctn relative to β-catenin, like that seen in normal-to-cancer cell phenotypic transformation. Additionally, claudin-7 cKO resulted in redistribution and relocalization of other cell junction proteins, including claudin-1, zonula occludens-1, integrin α2, epithelial cell adhesion molecule, and focal adhesion kinase (FAK); specifically, integrin α2 and FAK were observed at the apical-lateral compartment. Our data show that STORM reveals regional cellular junction nanoarchitecture previously uncharacterized, providing new insight into potential trans-compartmental modulation of protein functions.

Coptis chinensis polysaccharides dynamically influence the paracellular absorption pathway in the small intestine by modulating the intestinal mucosal immunity microenvironment

Background: Traditional Chinese Medicine decoctions (TCMDs) can be used to prepare outstanding pharmaceutical preparations by the patient themselves. Small molecular active ingredients and macromolecular polysaccharides are inevitably co-existed in TCMDs. Different from the pharmacological synergies among small molecules, the macromolecular polysaccharides in TCMDs might contribute to disease treatment in several ways, although it is frequently overlooked.Hypothesis/Purpose: This study proposes that the oral bioavailability of the water-insoluble alkaloids of Coptis chinensis Franch. (Ranunculaceae) (C. chinensis) decoction may be attributed to the co-existing C. chinensis polysaccharides (CCPs) dynamically influencing the small intestine microenvironment and regulating the modulation of the paracellular absorption pathway.Methods: First, the effects of CCPs on the oral bioavailability of the main active ingredient of C. chinensis, berberine, were evaluated in vivo. Next, a series of in situ experimental models of intestinal perfusion and models of isolated jejunal mucosa, Caco-2 cell monolayer membranes, and microfold-like cells were established to assess the correlation among CCPs, intestinal mucosal immunity, and paracellular absorption in the small intestine.Results: It was observed that CCPs could be endocytosed by the microfold cells on the surface of Peyer's patches, allowing CCPs to activate the lymphocytes, modulate the balance of Th1/Th2, control the secretion of immune effectors IFN-γ and IL-4, and finally regulate the tight junctions in the intestinal epithelial cells. This was a dynamic process with the movement of CCPs in the gastrointestinal tract that altered the flora distribution and functioning of the TLR/NF-κB signal pathway in the small intestine.Conclusion: The dynamical regulation of CCP on the immune microenvironment of small intestine is responsible for its promotion on the health controlling effects of C. chinensis in traditional dosage forms of decoction.

Chlamydiosis and cystic dilatation of the ovarian bursa in the female koala (Phascolarctos cinereus): Novel insights into the pathogenesis and mechanisms of formation

Infection with Chlamydia pecorum is one of the main causes of progressive decline of koala (Phascolarctos cinereus) populations in Eastern Australia. Pathological changes associated with the chlamydial infection in the genital tract of female and male koalas have been widely described with reports of acute and chronic lymphoplasmacytic inflammation and the description of the cystic dilatation of the ovarian bursa. Although these disease manifestations can result in severe chronic inflammation, structural changes and even sterility, only limited data is currently available on the organism's distribution and associated histopathological and ultrastructural changes within the upper genital tract of affected females.This study examined the pathogenesis of the most common pathological lesion associated with chlamydiosis in female koalas, the cystic dilation of the ovarian bursa starting from the evidence that Chlamydia spp. induces disruption of the intercellular junctions in the epithelium of the reproductive organs in humans. Histology, immunohistochemistry (IHC) and transmission electron microscopy (TEM) were performed to evaluate the structural features and the expression of epithelial cell and cellular junctions’ markers in affected bursae from 39 Chlamydia-infected female koalas. Epithelial cells from the ovarian bursae of one affected animal examined by transmission electron microscopy showed severe widening of the intercellular space, as morphologic evidence of disrupted permeability of the epithelial barrier. The epithelial cell-cell junctions markers E-cadherin, β-catenin and ZO-1 expressions were significantly reduced in samples from cystic bursae when compared to normal tissue samples (P < 0.0001). On the other end, a significantly higher expression of the proliferation marker Ki67 was observed in cystic bursae compared to control samples (P < 0.0001). As these proteins are required to maintain epithelial functional integrity and cell-cell adhesive interactions, their loss may permanently impair and affect female koala fertility and suggest the molecular basis of the pathogenesis of the cystic accumulation of bursal fluid within this tissue.

Relief Effects of Icariin on Inflammation-Induced Decrease of Tight Junctions in Intestinal Epithelial Cells.

Inflammatory cytokines including TNF-α and IL-1β impair intestinal barrier function in aging by disrupting intestinal tight junction integrity. Icariin (ICA) has a variety of pharmacological effects. Indeed, ICA produces anti-inflammatory, anti-oxidative stress, and inhibitory effects on microRNA (miRNA) expression. This study was to explore whether ICA could alleviate inflammation-associated intestinal barrier function impairment in aging and its underlying mechanism. Of particular interest, network pharmacology prediction indicated the potential therapeutic impacts of ICA for the treatment of colitis. Then, rats were used to study whether ICA has a protective effect on the reduction of tight junctions caused by inflammatory cytokines. Next, Caco-2 cell monolayers were used to explore the mechanism by which ICA alleviates the down-regulation of tight junctions. Network pharmacology prediction revealed that ICA alleviated colitis via suppressing oxidative stress. After ICA intervention, expressions of inflammatory cytokines were reduced, but tight junctions, antioxidant enzymes in aging rats were up-regulated. ICA reversed the TNF-α-induced decrease in abundance of Occludin protein in Caco-2 cell monolayers. Meanwhile, ICA alleviated the increase in permeability and expression of miR-122a. However, the protective effect of ICA was markedly attenuated after transfection with miR-122a mimics. In conclusion, ICA reduced the expressions of Occludin, Claudin1, and Claudin5 in colon, which were related to the reduction of TNF-α and IL-1β and alleviation of colonic in vivore. And ICA attenuated TNF-α-induced Occludin disruption and epithelial barrier impairment by decreasing miR-122a expression in Caco-2 cell monolayers.