Adherens and tight junctions: structure, function and connections to the actin cytoskeleton

MiR-29a-3p promotes nasal epithelial barrier dysfunction via direct targeting of CTNNB1-VCL module in allergic rhinitis

Allergic rhinitis (AR) is resulted from immunoglobulin E (IgE)-mediated reactions to inhaled allergens which elicit mucosal inflammation and impair epithelial barrier integrity. However, whether miR-29a-3p as an epigenetic regulator that can contribute to epithelial barrier dysfunction in the pathogenesis of AR, and its underlying mechanism remians unclear. In this study, we discovered that miR-29a-3p was upregulated in AR patients and preferentially expressed in epithelial and glandular cells of nasal mucosa. VCL and CTNNB1, candidate target genes of miR-29a-3p, were predicted with several databases, including miRDB, miRanda, microT-CDS and TargetScan, and were validated through dual-luciferase reporter assay system. These two proteins were strongly associated with adherens junction (AJ) and tight junction (TJ) of nasal mucosa epithelial cells, in which played vital roles in mucosal integrity and nasal epithelial barrier function stability. Results for HNEpC culture and in vitro treatment experiments showed that expression of VCL and CTNNB1 were inhibited by miR-29a-3p mimic and were enhanced by miR-29a-3p inhibitor. In OVA-induced AR mice model, the expression pattern of miR-29a-3p and its target genes (Vcl and Ctnnb1) were consistent with the aforementioned quantitative results in AR patients, and miR-29a-3p antagomir could partially alleviate the symptom of OVA-induced AR in mice, restoring mucosal integrity and paracellular barrier function. In conclusion, our findings indicate that miR-29a-3p targets CTNNB1 and VCL to regulate nasal epithelial permeability and barrier function integrity, which may serve as a potential novel therapeutic target for the treatment of AR.

Cerebrospinal Fluid-Basic Concepts Review

Cerebrospinal fluid plays a crucial role in protecting the central nervous system (CNS) by providing mechanical support, acting as a shock absorber, and transporting nutrients and waste products. It is produced in the ventricles of the brain and circulates through the brain and spinal cord in a continuous flow. In the current review, we presented basic concepts related to cerebrospinal fluid history, cerebrospinal fluid production, circulation, and its main components, the role of the blood-brain barrier and the blood-cerebrospinal fluid barrier in the maintenance of cerebrospinal fluid homeostasis, and the utility of Albumin Quotient (Q_Alb) evaluation in the diagnosis of CNS diseases. We also discussed the collection of cerebrospinal fluid (type, number of tubes, and volume), time of transport to the laboratory, and storage conditions. Finally, we briefly presented the role of cerebrospinal fluid examination in CNS disease diagnosis of various etiologies and highlighted that research on identifying cerebrospinal fluid biomarkers indicating disease presence or severity, evaluating treatment effectiveness, and enabling understanding of pathogenesis and disease mechanisms is of great importance. Thus, in our opinion, research on cerebrospinal fluid is still necessary for both the improvement of CNS disease management and the discovery of new treatment options.

Es-β-CATENIN affects the hemolymph-testes barrier in Eriocheir sinensis by disrupting cell junctions and cytoskeleton

β-CATENIN is an evolutionarily conserved multifunctional molecule that maintains cell adhesion as a cell junction protein to safeguard the integrity of the mammalian blood-testes barrier, and also regulates cell proliferation and apoptosis as a key signaling molecule in the WNT/β-CATENIN signaling pathway. In the crustacean Eriocheir sinensis, Es-β-CATENIN has been shown to be involved in spermatogenesis, but the testes of E. sinensis have large and well-defined structural differences from those of mammals, and the impact of Es-β-CATENIN in them is still unknown. In the present study, we found that Es-β-CATENIN, Es-α-CATENIN and Es-ZO-1 interact differently in the testes of the crab compared to mammals. In addition, defective Es-β-CATENIN resulted in increased Es-α-CATENIN protein expression levels, distorted and deformed F-ACTIN, and disturbed localization of Es-α-CATENIN and Es-ZO-1, leading to loss of hemolymph-testes barrier integrity and impaired sperm release. In addition to this, we also performed the first molecular cloning and bioinformatics analysis of Es-AXIN in the WNT/β-CATENIN pathway to exclude the effect of the WNT/β-CATENIN pathway on the cytoskeleton. In conclusion, Es-β-CATENIN participates in maintaining the hemolymph-testes barrier in the spermatogenesis of E. sinensis.

Biomechanical models and mechanisms of cellular morphogenesis and cerebral cortical expansion and folding

Morphogenesis of the nervous system involves a highly complex spatio-temporal pattern of physical forces (mainly tension and pressure) acting on cells and tissues that are pliable but have an intricately organized cytoskeletal infrastructure. This review begins by covering basic principles of biomechanics and the core cytoskeletal toolkit used to regulate the shapes of cells and tissues during embryogenesis and neural development. It illustrates how the principle of 'tensegrity' provides a useful conceptual framework for understanding how cells dynamically respond to forces that are generated internally or applied externally. The latter part of the review builds on this foundation in considering the development of mammalian cerebral cortex. The main focus is on cortical expansion and folding - processes that take place over an extended period of prenatal and postnatal development. Cortical expansion and folding are likely to involve many complementary mechanisms, some related to regulating cell proliferation and migration and others related to specific types and patterns of mechanical tension and pressure. Three distinct multi-mechanism models are evaluated in relation to a set of 18 key experimental observations and findings. The Composite Tension Plus (CT+) model is introduced as an updated version of a previous multi-component Differential Expansion Sandwich Plus (DES+) model (Van Essen, 2020); the new CT+ model includes 10 distinct mechanisms and has the greatest explanatory power among published models to date. Much needs to be done in order to validate specific mechanistic components and to assess their relative importance in different species, and important directions for future research are suggested.

Immunoglobulin E-virus phenotypes of infant bronchiolitis and risk of childhood asthma

Background

Bronchiolitis is the leading cause of infant hospitalization in U.S. and is associated with increased risk for childhood asthma. Immunoglobulin E (IgE) not only plays major roles in antiviral immune responses and atopic predisposition, but also offers a potential therapeutic target.

Objective

We aimed to identify phenotypes of infant bronchiolitis by using total IgE (tIgE) and virus data, to determine their association with asthma development, and examine their biological characteristics.

Methods

In a multicenter prospective cohort study of 1,016 infants (age <1 year) hospitalized for bronchiolitis, we applied clustering approaches to identify phenotypes by integrating tIgE and virus (respiratory syncytial virus [RSV], rhinovirus [RV]) data at hospitalization. We examined their longitudinal association with the risk of developing asthma by age 6 years and investigated their biological characteristics by integrating the upper airway mRNA and microRNA data in a subset (n=182).

Results

In infants hospitalized for bronchiolitis, we identified 4 phenotypes: 1) tIgE^lowvirus^RSV-high, 2) tIgE^lowvirus^RSV-low/RV, 3) tIgE^highvirus^RSV-high, and 4) tIgE^highvirus^RSV-low/RV phenotypes. Compared to phenotype 1 infants (resembling "classic" bronchiolitis), phenotype 4 infants (tIgE^highvirus^RSV-low/RV) had a significantly higher risk for developing asthma (19% vs. 43%; adjOR, 2.93; 95% CI, 1.02-8.43; P=.046). Phenotypes 3 and 4 (tIgE^high) had depleted type I interferon and enriched antigen presentation pathways; phenotype 4 also had depleted airway epithelium structure pathways.

Conclusions

In this multicenter cohort, tIgE-virus clustering identified distinct phenotypes of infant bronchiolitis with differential risks of asthma development and unique biological characteristics.

Fungal Aeroallergens-The Impact of Climate Change

The incidence of allergic diseases worldwide is rapidly increasing, making allergies a modern pandemic. This article intends to review published reports addressing the role of fungi as causative agents in the development of various overreactivity-related diseases, mainly affecting the respiratory tract. After presenting the basic information on the mechanisms of allergic reactions, we describe the impact of fungal allergens on the development of the allergic diseases. Human activity and climate change have an impact on the spread of fungi and their plant hosts. Particular attention should be paid to microfungi, i.e., plant parasites that may be an underestimated source of new allergens.

Basal Intestinal Morphology, Immunolocalization of Leptin and Ghrelin and Their Receptors in Newborn Wistar Rats after Prenatal Exposure to Fumonisins

Animal feed is very frequently contaminated with different types of mold, the metabolites of which are toxic to living organisms. Mold-contaminated cereal is rich in heat-resistant and harmful metabolites such as fumonisins (FBs). The amount of FBs consumed as part of animal feed, including livestock feed, is unknown. Therefore, this study aimed to evaluate the effects of maternal oral FB intoxication on basal duodenum morphology and the immunolocalization of gut hormones responsible for food intake (leptin and ghrelin), as well as their receptors, in newborn rat offspring. Pregnant Wistar rats were randomly allocated to one of three groups: a control group or one of two FB-intoxicated groups (60 or 90 mg FB/kg b.w., respectively). Basal morphological duodenal parameters changed in a dose- and sex-dependent manner. The intensity of the ghrelin immunoreaction was unchanged in females, while in males it increased after FB exposure (60 mg/kg b.w.), with a simultaneous decrease in expression of the ghrelin receptor. Leptin and its receptor immunoreaction intensity was decreased in both sexes following FB exposure. The current study highlighted the potential involvement of intestinal ghrelin and leptin in the metabolic disturbances observed later in life in offspring that were prenatally exposed to fumonisins.

Endotheliopathy in Acute COVID-19 and Long COVID

The pulmonary endothelium is a highly regulated organ that performs a wide range of functions under physiological and pathological conditions. Since endothelial dysfunction has been demonstrated to play a direct role in sepsis and acute respiratory distress syndrome, its role in COVID-19 has also been extensively investigated. Indeed, apart from the COVID-19-associated coagulopathy biomarkers, new biomarkers were recognised early during the pandemic, including markers of endothelial cell activation or injury. We systematically searched the literature up to 10 March 2023 for studies examining the association between acute and long COVID-19 severity and outcomes and endothelial biomarkers.

Selenium Deficiency Promotes the Expression of LncRNA-MORC3, Activating NLRP3-Caspase-1/IL-1β Signaling to Induce Inflammatory Damage and Disrupt Tight Junctions in Piglets

Selenium (Se), as a trace element, is widely found in animals in the form of selenomethionine, which can provide nutrition to the body and has anti-inflammatory effects to prevent inflammatory damage in animals. In the past decade, there have been many studies on piglet diseases caused by selenium deficiency; however, under Se deficiency, the relationship between LncRNA-MORC3, inflammatory injury, and tight junctions in piglets has not yet been studied. We established piglet selenium deficiency models divided into three groups and obtained small intestinal tissues after 35 days of feeding. Small intestinal epithelial IPEC-J2 cells were divided into three groups, and samples were collected after 24 h of culture for qPCR and Western blot experiments. First, we found that Se deficiency led to an increase in LncRNA-MORC3 expression in piglets in vivo and in vitro. We found that the binding site of NLRP3 on LncRNA-MORC3 and the expression trends of both were the same: Se deficiency increased the secretion of NLRP3 and the expression levels of the inflammatory factors Caspase-1, ASC, IL-1β, IL-17, IL-6, IL-10, and TNF-α, which are related to the NLRP3-Caspase-1/IL-1β signaling pathway. At the same time, Se deficiency decreased the expression levels of the tight junction factors ZO-1, Z0-2, Occludin, E-cadherin, and ZEB-1. This result showed that the tight junctions were disrupted. Herein, we demonstrated that Se deficiency promotes the expression of both LncRNA-MORC3 and inflammatory factors in piglets to activate the NLRP3-Caspase-1/IL-1β signaling pathway and disrupt tight junctions. Ultimately, these factors lead to inflammatory damage in piglet small intestinal tissues.

Oral Metal-Free Melanin Nanozymes for Natural and Durable Targeted Treatment of Inflammatory Bowel Disease (IBD)

Oral antioxidant nanozymes bring great promise for inflammatory bowel disease (IBD) treatment. To efficiently eliminate reactive oxygen species (ROS), various metal-based nanozymes have been developed for the treatment of IBD but their practical applications are seriously impaired by unstable ROS-eliminating properties and potential metal ion leakage in the digestive tract. Here, the authors for the first time propose metal-free melanin nanozymes (MeNPs) with excellent gastrointestinal stability and biocompatibility as a favorable therapy strategy for IBD. Moreover, MeNPs have extremely excellent natural and long-lasting characteristics of targeting IBD lesions. In view of the dominant role of ROS in IBD, the authors further reveal that oral administration of MeNPs can greatly alleviate the six major pathological features of IBD: oxidative stress, endoplasmic reticulum stress, apoptosis, inflammation, gut barrier disruption, and gut dysbiosis. Overall, this strategy highlights the great clinical application prospects of metal-free MeNPs via harnessing ROS scavenging at IBD lesions, offering a paradigm for antioxidant nanozyme in IBD or other inflammatory diseases.

Mechanobiological Adaptation to Hyperosmolarity Enhances Barrier Function in Human Vascular Microphysiological System

In infectious disease such as sepsis and COVID-19, blood vessel leakage treatment is critical to prevent fatal progression into multi-organ failure and ultimately death, but the existing effective therapeutic modalities that improve vascular barrier function are limited. Here, this study reports that osmolarity modulation can significantly improve vascular barrier function, even in an inflammatory condition. 3D human vascular microphysiological systems and automated permeability quantification processes for high-throughput analysis of vascular barrier function are utilized. Vascular barrier function is enhanced by >7-folds with 24-48 h hyperosmotic exposure (time window of emergency care; >500 mOsm L^-1 ) but is disrupted after hypo-osmotic exposure (<200 mOsm L^-1 ). By integrating genetic and protein level analysis, it is shown that hyperosmolarity upregulates vascular endothelial-cadherin, cortical F-actin, and cell-cell junction tension, indicating that hyperosmotic adaptation mechanically stabilizes the vascular barrier. Importantly, improved vascular barrier function following hyperosmotic exposure is maintained even after chronic exposure to proinflammatory cytokines and iso-osmotic recovery via Yes-associated protein signaling pathways. This study suggests that osmolarity modulation may be a unique therapeutic strategy to proactively prevent infectious disease progression into severe stages via vascular barrier function protection.

House dust mite allergy: The importance of house dust mite allergens for diagnosis and immunotherapy

House dust mite (HDM) allergy belongs to the most important allergies and affects approximately 65-130 million people worldwide. Additionally, untreated HDM allergy may lead to the development of severe disease manifestations such as atopic dermatitis or asthma. Diagnosis and immunotherapy of HDM allergic patients are well established but are often hampered by the use of mite extracts that are of bad quality and lack important allergens. The use of individual allergens seems to be a promising alternative to natural allergen extracts, since they represent well-defined components that can easily be produced and quantified. However, a thorough characterization of the individual allergens is required to determine their clinical relevance and to identify those allergens that are required for correct diagnosis of HDM allergy and for successful immunotherapy. This review gives an update on the individual HDM allergens and their benefits for diagnosis and immunotherapy of HDM allergic patients.

Salivary E-cadherin as a biomarker for diagnosis and predicting grade of periodontitis

OBJECTIVES

To determine the abilities of salivary E-cadherin to differentiate between periodontal health and periodontitis and to discriminate grades of periodontitis.

BACKGROUND

E-cadherin is the main protein responsible for maintaining the integrity of epithelial-barrier function. Disintegration of this protein is one of the events associated with the destructive forms of periodontal disease leading to increase concentration of E-cadherin in the oral biofluids.

MATERIALS AND METHODS

A total of 63 patients with periodontitis (case) and 35 periodontally healthy subjects (control) were included. For each patient, periodontal parameters including bleeding on probing (BOP), probing pocket depth (PPD), and clinical attachment level (CAL) were recorded. Concentration of salivary E-cadherin was determined by ELISA. Receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to determine the diagnostic potentials of E-cadherin.

RESULTS

Level of salivary E-cadherin was significantly higher in periodontitis cases than controls. The ROC analysis showed that salivary E-cadherin exhibits excellent sensitivity and specificity (AUC 1.000) to differentiate periodontal health from periodontitis with a cutoff concentration equal to 1.325 ng/mL. The AUCs of E-cadherin to differentiate grade A from grade B and C periodontitis were 0.731 (cutoff point = 1.754 ng/mL) and 0.746 (cutoff point = 1.722 ng/mL), respectively. However, the AUC of salivary E-cadherin to differentiate grade B from grade C periodontitis was lower (0.541). Additionally, BOP and PPD were significantly and positively correlated with the concentration of salivary E-cadherin.

CONCLUSION

Salivary E-cadherin exhibited excellent sensitivity and specificity to differentiate periodontitis from a healthy periodontium. The level of accuracy of E-cadherin was also sufficient to recognize grade A periodontitis from grade B and C periodontitis.

Junctional integrity and directional mobility of lymphatic endothelial cell monolayers are disrupted by saturated fatty acids

The lymphatic circulation regulates transfer of tissue fluid and immune cells toward the venous circulation. While obesity impairs lymphatic vessel function, the contribution of lymphatic endothelial cells (LEC) to metabolic disease phenotypes is poorly understood. LEC of lymphatic microvessels are in direct contact with the interstitial fluid, whose composition changes during the development of obesity, markedly by increases in saturated fatty acids. Palmitate, the most prevalent saturated fatty acid in lymph and blood, is detrimental to metabolism and function of diverse tissues, but its impact on LEC function is relatively unknown. Here, palmitate (but not its unsaturated counterpart palmitoleate) destabilized adherens junctions in human microvascular LEC in culture, visualized as changes in VE-cadherin, α-catenin, and β-catenin localization. Detachment of these proteins from cortical actin filaments was associated with abundant actomyosin stress fibers. The effects were Rho-associated protein kinase (ROCK)- and myosin-dependent, as inhibition with Y27632 or blebbistatin, respectively, prevented stress fiber accumulation and preserved junctions. Without functional junctions, palmitate-treated LEC failed to directionally migrate to close wounds in two dimensions and failed to form endothelial tubes in three dimensions. A reorganization of the lymphatic endothelial actin cytoskeleton may contribute to lymphatic dysfunction in obesity and could be considered as a therapeutic target.

Differential bumble bee gene expression associated with pathogen infection and pollen diet

BACKGROUND

Diet and parasitism can have powerful effects on host gene expression. However, how specific dietary components affect host gene expression that could feed back to affect parasitism is relatively unexplored in many wild species. Recently, it was discovered that consumption of sunflower (Helianthus annuus) pollen reduced severity of gut protozoan pathogen Crithidia bombi infection in Bombus impatiens bumble bees. Despite the dramatic and consistent medicinal effect of sunflower pollen, very little is known about the mechanism(s) underlying this effect. However, sunflower pollen extract increases rather than suppresses C. bombi growth in vitro, suggesting that sunflower pollen reduces C. bombi infection indirectly via changes in the host. Here, we analyzed whole transcriptomes of B. impatiens workers to characterize the physiological response to sunflower pollen consumption and C. bombi infection to isolate the mechanisms underlying the medicinal effect. B. impatiens workers were inoculated with either C. bombi cells (infected) or a sham control (un-infected) and fed either sunflower or wildflower pollen ad libitum. Whole abdominal gene expression profiles were then sequenced with Illumina NextSeq 500 technology.

RESULTS

Among infected bees, sunflower pollen upregulated immune transcripts, including the anti-microbial peptide hymenoptaecin, Toll receptors and serine proteases. In both infected and un-infected bees, sunflower pollen upregulated putative detoxification transcripts and transcripts associated with the repair and maintenance of gut epithelial cells. Among wildflower-fed bees, infected bees downregulated immune transcripts associated with phagocytosis and the phenoloxidase cascade.

CONCLUSIONS

Taken together, these results indicate dissimilar immune responses between sunflower- and wildflower-fed bumble bees infected with C. bombi, a response to physical damage to gut epithelial cells caused by sunflower pollen, and a strong detoxification response to sunflower pollen consumption. Identifying host responses that drive the medicinal effect of sunflower pollen in infected bumble bees may broaden our understanding of plant-pollinator interactions and provide opportunities for effective management of bee pathogens.

Protective Effect of Limosilactobacillus fermentum ME-3 against the Increase in Paracellular Permeability Induced by Chemotherapy or Inflammatory Conditions in Caco-2 Cell Models

Chemotherapy- or inflammation-induced increase in intestinal permeability represents a severe element in disease evolution in patients suffering from colorectal cancer and gut inflammatory conditions. Emerging data strongly support the gut microbiota’s role in preserving intestinal barrier integrity, whilst both chemotherapy and gut inflammation alter microbiota composition. Some probiotics might have a strong re-balancing effect on the gut microbiota, also positively affecting intestinal barrier integrity. In this study, we asked whether Limosilactobacillus fermentum ME-3 can prevent the intestinal paracellular permeability increase caused by the chemotherapeutic drug Irinotecan or by inflammatory stimuli, such as lipopolysaccharide (LPS). As an intestinal barrier model, we used a confluent and polarized Caco-2 cell monolayer and assessed the ME-3-induced effect on paracellular permeability by transepithelial electrical resistance (TEER) and fluorescent-dextran flux assays. The integrity of tight and adherens junctions was examined by confocal microscopy analysis. Transwell co-cultures of Caco-2 cells and U937-derived macrophages were used as models of LPS-induced intestinal inflammation to test the effect of ME-3 on release of the pro-inflammatory cytokines Tumor Necrosis Factor α, Interleukin-6, and Interleukin-8, was measured by ELISA. The results demonstrate that ME-3 prevents the IRI-induced increment in paracellular permeability, possibly by modulating the expression and localization of cell junction components. In addition, ME-3 inhibited both the increase in paracellular permeability and the release of pro-inflammatory cytokines in the co-culture model of LPS-induced inflammation. Our findings sustain the validity of L. fermentum ME-3 as a valuable therapeutic tool for preventing leaky gut syndrome, still currently without an available specific treatment.

Epithelial-Mesenchymal Plasticity: Implications for Ferroptosis Vulnerability and Cancer Therapy

Cancers polarized to a mesenchymal or poorly differentiated state can often evade cell death induced by conventional therapies. The epithelial-mesenchymal transition is involved in lipid metabolism and increases polyunsaturated fatty acid levels in cancer cells, contributing to chemo- and radio-resistance. Altered metabolism in cancer enables invasion and metastasis but is prone to lipid peroxidation under oxidative stress. Cancers with mesenchymal rather than epithelial signatures are highly vulnerable to ferroptosis. Therapy-resistant persister cancer cells show a high mesenchymal cell state and dependence on the lipid peroxidase pathway, which can respond more sensitively to ferroptosis inducers. Cancer cells may survive under specific metabolic and oxidative stress conditions, and targeting this unique defense system can selectively kill only cancer cells. Therefore, this article summarizes the core regulatory mechanisms of ferroptosis in cancer, the relationship between ferroptosis and epithelial-mesenchymal plasticity, and the implications of epithelial-mesenchymal transition for ferroptosis-based cancer therapy.

Isopropyl 3-(3, 4-dihydroxyphenyl)-2-hydroxypropanoate protects lipopolysaccharide-induced acute lung injury in mice by attenuating pyroptosis

Isopropyl 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate (IDHP) is one of the main bioactive metabolites of the Chinese medicinal herb Danshen, which can be absorbed into blood compounds by oral administration of Compound Danshen dripping pills (CDDPs). Previous study showed that IDHP exerted anti-inflammatory effects by abolishing the secretion of proinflammatory factors stimulated by lipopolysaccharide (LPS). However, the effects of IDHP on LPS-induced acute lung injury (ALI) are not fully understood. In the present study, we observed the effects of IDHP on mortality and lung injury in LPS-treated mice and on LPS-induced THP-1 macrophages. Pretreatment with high dose of IDHP was found to reduce the mortality of ALI mice, significantly improve LPS-induced pathological changes, and reduce protein leakage and inhibited myeloperoxidase (MPO) activity in lung tissue. IDHP also inhibited the release of inflammatory factors in bronchoalveolar lavage fluid (BALF) and lung tissue. Meanwhile, IDHP treatment significantly reduced the expression of active-caspase1, Nlrp3, Asc speck formation, Gsdmd (part of the canonical pyroptosis pathway), caspase4 (part of the non-canonical pyroptosis pathway), therefore decreasing IL-1β, IL-18, and ROS secretion in LPS-stimulated THP-1 macrophages. Moreover, after co-culturing endothelial/epithelial cells with conditioned medium (CM) from LPS-stimulated THP-1 macrophages, we found that the protein levels of occludin and Zonula occludens-1 (Zo-1) were increased in IDHP CM-treated endothelial cells compared to those that were LPS CM-treated. Lactic dehydrogenase (LDH) assay shows that IDHP also alleviated LPS-induced endothelial/epithelial cell injury. These findings indicate that the protective effect of IDHP on LPS-induced lung injury may be partly due to the inhibition of pyroptosis pathways.

m6A modification in inflammatory bowel disease provides new insights into clinical applications

Inflammatory bowel disease (IBD) results from a complex interplay between genetic predisposition, environmental factors, and gut microbes. The role of N6-methyladenosine (m6A) methylation in the pathogenesis of IBD has attracted increasing attention. m6A modification not only regulates intestinal mucosal immunity and intestinal barrier function, but also affects apoptosis and autophagy in intestinal epithelial cells. Additionally, m6A modification participated in the interaction between gut microbes and the host, providing a novel direction to explore the molecular mechanisms of IBD and the theoretical basis for specific microorganism-oriented prevention and treatment measures. m6A regulators are expected to be biomarkers for predicting the prognosis of IBD patients. m6A methylation may be utilized as a novel target in the management of IBD. This review focused on the recent advances in how m6A modification causes the initiation and development of IBD, and provided new insights into optimal prevention and treatment measures for IBD.

Clinical and prognostic features of E-cadherin in adenocarcinoma of the esophagogastric junction patients

OBJECTIVE

The expression, activity, and functional role of E-cadherin in adenocarcinoma of the esophagogastric junction (AEG) are unclear. In this research, we evaluated the expression of E-cadherin in AEG, as well as its clinicopathological significance and prognostic value.

METHODS

A total of 65 AEG samples and 10 normal paracancerous tissues undergoing AEG resection in thoracic surgery were collected. The samples were immunohistochemically examined for expression levels of E-cadherin. The Chi-square test was used to determine if E-cadherin expression correlated with the clinicopathological features of AEG patients. The link between clinicopathological features and 5-year survival rates was investigated using Kaplan-Meier survival curves and multifactorial Cox regression analysis.

RESULTS

In AEG tissues, E-cadherin expression was considerably reduced. Differentiation grade ( P = 0.013), infiltration depth ( P = 0.033), and clinicopathological stage ( P = 0.045) were substantially linked to the level of E-cadherin expression. Five-year survival rates of AEG patients were affected by E-cadherin expression ( P = 0.037), tumor differentiation ( P = 0.010), lymph node metastasis ( P < 0.001), and clinicopathological stage ( P = 0.037). Tumor differentiation ( P = 0.033) and lymph node metastasis ( P = 0.001) were independent risk factors for shorter overall survival.

CONCLUSION

E-cadherin expression in AEG was significantly decreased, which was strongly related to tumor differentiation, infiltration, and clinicopathological stage. An E-cadherin deficiency would lead to poor prognosis in AEG patients. E-cadherin may play a crucial role in AEG invasion and metastasis. Low expression of E-cadherin may be a potential early biomarker and overall survival predictor for AEG patients.

The gut microbiome and hypertension

A large body of evidence has emerged in the past decade supporting a role for the gut microbiome in the regulation of blood pressure. The field has moved from association to causation in the last 5 years, with studies that have used germ-free animals, antibiotic treatments and direct supplementation with microbial metabolites. The gut microbiome can regulate blood pressure through several mechanisms, including through gut dysbiosis-induced changes in microbiome-associated gene pathways in the host. Microbiota-derived metabolites are either beneficial (for example, short-chain fatty acids and indole-3-lactic acid) or detrimental (for example, trimethylamine N-oxide), and can activate several downstream signalling pathways via G protein-coupled receptors or through direct immune cell activation. Moreover, dysbiosis-associated breakdown of the gut epithelial barrier can elicit systemic inflammation and disrupt intestinal mechanotransduction. These alterations activate mechanisms that are traditionally associated with blood pressure regulation, such as the renin-angiotensin-aldosterone system, the autonomic nervous system, and the immune system. Several methodological and technological challenges remain in gut microbiome research, and the solutions involve minimizing confounding factors, establishing causality and acting globally to improve sample diversity. New clinical trials, precision microbiome medicine and computational methods such as Mendelian randomization have the potential to enable leveraging of the microbiome for translational applications to lower blood pressure.

Dynamic mechanobiology of cardiac cells and tissues: Current status and future perspective

Mechanical forces impact cardiac cells and tissues over their entire lifespan, from development to growth and eventually to pathophysiology. However, the mechanobiological pathways that drive cell and tissue responses to mechanical forces are only now beginning to be understood, due in part to the challenges in replicating the evolving dynamic microenvironments of cardiac cells and tissues in a laboratory setting. Although many in vitro cardiac models have been established to provide specific stiffness, topography, or viscoelasticity to cardiac cells and tissues via biomaterial scaffolds or external stimuli, technologies for presenting time-evolving mechanical microenvironments have only recently been developed. In this review, we summarize the range of in vitro platforms that have been used for cardiac mechanobiological studies. We provide a comprehensive review on phenotypic and molecular changes of cardiomyocytes in response to these environments, with a focus on how dynamic mechanical cues are transduced and deciphered. We conclude with our vision of how these findings will help to define the baseline of heart pathology and of how these in vitro systems will potentially serve to improve the development of therapies for heart diseases.

Engineering Functional Membrane-Membrane Interfaces by InterSpy

Engineering synthetic interfaces between membranes has potential applications in designing non-native cellular communication pathways and creating synthetic tissues. Here, InterSpy is introduced as a synthetic biology tool consisting of a heterodimeric protein engineered to form and maintain membrane-membrane interfaces between apposing synthetic as well as cell membranes through the SpyTag/SpyCatcher interaction. The inclusion of split fluorescent protein fragments in InterSpy allows tracking of the formation of a membrane-membrane interface and reconstitution of functional fluorescent protein in the space between apposing membranes. First, InterSpy is demonstrated by testing split protein designs using a mammalian cell-free expression (CFE) system. By utilizing co-translational helix insertion, cell-free synthesized InterSpy fragments are incorporated into the membrane of liposomes and supported lipid bilayers with the desired topology. Functional reconstitution of split fluorescent protein between the membranes is strictly dependent on SpyTag/SpyCatcher. Finally, InterSpy is demonstrated in mammalian cells by detecting fluorescence reconstitution of split protein at the membrane-membrane interface between two cells each expressing a component of InterSpy. InterSpy demonstrates the power of CFE systems in the functional reconstitution of synthetic membrane interfaces via proximity-inducing proteins. This technology may also prove useful where cell-cell contacts and communication are recreated in a controlled manner using minimal components.

Airway Epithelium: A Neglected but Crucial Cell Type in Asthma Pathobiology

The features of allergic asthma are believed to be mediated mostly through the Th2 immune response. In this Th2-dominant concept, the airway epithelium is presented as the helpless victim of Th2 cytokines. However, this Th2-dominant concept is inadequate to fill some of the vital knowledge gaps in asthma pathogenesis, like the poor correlation between airway inflammation and airway remodeling and severe asthma endotypes, including Th2-low asthma, therapy resistance, etc. Since the discovery of type 2 innate lymphoid cells in 2010, asthma researchers started believing in that the airway epithelium played a crucial role, as alarmins, which are the inducers of ILC2, are almost exclusively secreted by the airway epithelium. This underscores the eminence of airway epithelium in asthma pathogenesis. However, the airway epithelium has a bipartite functionality in sustaining healthy lung homeostasis and asthmatic lungs. On the one hand, the airway epithelium maintains lung homeostasis against environmental irritants/pollutants with the aid of its various armamentaria, including its chemosensory apparatus and detoxification system. Alternatively, it induces an ILC2-mediated type 2 immune response through alarmins to amplify the inflammatory response. However, the available evidence indicates that restoring epithelial health may attenuate asthmatic features. Thus, we conjecture that an epithelium-driven concept in asthma pathogenesis could fill most of the gaps in current asthma knowledge, and the incorporation of epithelial-protective agents to enhance the robustness of the epithelial barrier and the combative capacity of the airway epithelium against exogenous irritants/allergens may mitigate asthma incidence and severity, resulting in better asthma control.

Complexification of In Vitro Models of Intestinal Barriers, A True Challenge for a More Accurate Alternative Approach

The use of cell models is common to mimic cellular and molecular events in interaction with their environment. In the case of the gut, the existing models are of particular interest to evaluate food, toxicants, or drug effects on the mucosa. To have the most accurate model, cell diversity and the complexity of the interactions must be considered. Existing models range from single-cell cultures of absorptive cells to more complex combinations of two or more cell types. This work describes the existing solutions and the challenges that remain to be solved.

Inhibitors against Two PDZ Domains of MDA-9 Suppressed Migration of Breast Cancer Cells

Melanoma differentiation-associated gene 9 (MDA-9) is a small adaptor protein with tandem PDZ domains that promotes tumor progression and metastasis in various human cancers. However, it is difficult to develop drug-like small molecules with high affinity due to the narrow groove of the PDZ domains of MDA-9. Herein, we identified four novel hits targeting the PDZ1 and PDZ2 domains of MDA-9, namely PI1A, PI1B, PI2A, and PI2B, using a protein-observed nuclear magnetic resonance (NMR) fragment screening method. We also solved the crystal structure of the MDA-9 PDZ1 domain in complex with PI1B and characterized the binding poses of PDZ1-PI1A and PDZ2-PI2A, guided by transferred paramagnetic relaxation enhancement. The protein-ligand interaction modes were then cross-validated by the mutagenesis of the MDA-9 PDZ domains. Competitive fluorescence polarization experiments demonstrated that PI1A and PI2A blocked the binding of natural substrates to the PDZ1 and PDZ2 domains, respectively. Furthermore, these inhibitors exhibited low cellular toxicity, but suppressed the migration of MDA-MB-231 breast carcinoma cells, which recapitulated the phenotype of MDA-9 knockdown. Our work has paved the way for the development of potent inhibitors using structure-guided fragment ligation in the future.

Transcriptome Analysis Revealed Osmoregulation Related Regulatory Networks and Hub Genes in the Gills of Hilsa shad, Tenualosa ilisha, during the Migratory Osmotic Stress

Tenualosa ilisha (Hilsa shad), an anadromous fish, usually inhabits coastal and estuarine waters, and migrates to freshwater for spawning. In this study, large-scale gill transcriptome analyses from three salinity regions, i.e., fresh, brackish and marine water, revealed 3277 differentially expressed genes (DEGs), out of which 232 were found to be common between marine vs freshwater and brackish vs freshwater. These genes were mapped into 54 KEGG Pathways, and the most significant of these were focal adhesion, adherens junction, tight junction, and PI3K-Akt signaling pathways. A total of 24 osmoregulatory genes were found to be differentially expressed in different habitats. The gene members of slc16 and slc2 families showed a dissimilar pattern of expressions, while two claudin genes (cldn11 & cldn10), transmembrane tm56b, and voltage-gated potassium channel gene kcna10 were downregulated in freshwater samples, as compared to that of brackish and marine environment. Protein-protein interaction (PPI) network analysis of 232 DEGs showed 101 genes to be involved in PPI, while fn1 gene was found to be interacting with the highest number of genes (36). Twenty-five hub genes belonged to 12 functional groups, with muscle structure development with seven genes, forming the major group. These results provided valuable information about the genes, potentially involved in the molecular mechanisms regulating water homeostasis in gills, during migration for spawning and low-salinity adaptation in Hilsa shad. These genes may form the basis for the bio-marker development for adaptation to the stress levied by major environmental changes, due to hatchery/culture conditions.

Paradigms of endothelial stiffening in cardiovascular disease and vascular aging

Endothelial cells, the inner lining of the blood vessels, are well-known to play a critical role in vascular function, while endothelial dysfunction due to different cardiovascular risk factors or accumulation of disruptive mechanisms that arise with aging lead to cardiovascular disease. In this review, we focus on endothelial stiffness, a fundamental biomechanical property that reflects cell resistance to deformation. In the first part of the review, we describe the mechanisms that determine endothelial stiffness, including RhoA-dependent contractile response, actin architecture and crosslinking, as well as the contributions of the intermediate filaments, vimentin and lamin. Then, we review the factors that induce endothelial stiffening, with the emphasis on mechanical signals, such as fluid shear stress, stretch and stiffness of the extracellular matrix, which are well-known to control endothelial biomechanics. We also describe in detail the contribution of lipid factors, particularly oxidized lipids, that were also shown to be crucial in regulation of endothelial stiffness. Furthermore, we discuss the relative contributions of these two mechanisms of endothelial stiffening in vasculature in cardiovascular disease and aging. Finally, we present the current state of knowledge about the role of endothelial stiffening in the disruption of endothelial cell-cell junctions that are responsible for the maintenance of the endothelial barrier.

Improvement of the intestinal epithelial barrier during laxative effects of phlorotannin in loperamide-induced constipation of SD rats

BACKGROUND

Disruptions of the intestinal epithelial barrier (IEB) are frequently observed in various digestive diseases, including irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). This study assessed the improvement in the IEB during the laxative activity of phlorotannin (Pt) harvested from Ecklonia cava in constipation by examining the changes in the expression of the regulatory proteins for the tight junction (TJ) and adherens junction (AJ), and inflammatory cytokines in Sprague Dawley (SD) rats with loperamide (Lm)-induced constipation after a Pt treatment.

RESULTS

The Pt treatment induced laxative activity, including the improvement of feces-related parameters, gastrointestinal transit rate, and histological structure of the mid colon in Lm-treated SD rats. In addition, significant recovery effects were detected in the histology of IEB, including the mucus layer, epithelial cells, and lamina propria in the mid colon of Lm + Pt treated SD rats. The expression levels of E-cadherin and p120-catenin for AJ and the ZO-1, occludin, and Claudin-1 genes for TJ in epithelial cells were improved remarkably after the Pt treatment, but the rate of increase was different. Furthermore, the Pt treatment increased the expression level of several inflammatory cytokines, such as TNF-α, IL-6, IL-1β, IL-13, and IL-4 in Lm + Pt treated SD rats.

CONCLUSIONS

These results provide the first evidence that the laxative activity of Pt in SD rats with Lm-induced constipation phenotypes involve improvements in the IEB.

Pathogenesis and treatment of chronic rhinosinusitis from the perspective of sinonasal epithelial dysfunction

Background

Chronic rhinosinusitis (CRS) is a clinical syndrome primarily characterized by long-term mucosal inflammation of the nasal cavity and sinuses. The pathogenesis of CRS is still unclear due to its high heterogeneity. A number of studies have recently focused on the sinonasal epithelium. Thus, there has been a quantum leap in awareness of the role of the sinonasal epithelium, which is now understood as an active functional organ rather than simply an inert mechanical barrier. Undoubtedly, epithelial dysfunction plays a vital role in the onset and development of CRS.

Objective

In this article, we discuss the potential contribution of sinonasal epithelium dysfunction to CRS pathogenesis and explore a few current and developing therapeutic options targeting the sinonasal epithelium.

Results

Impaired mucociliary clearance (MCC) and an abnormal sinonasal epithelial barrier are usually considered to be the main causative factors in CRS. Epithelial-derived bioactive substances, such as cytokines, exosomes, and complements, play a vital role in the regulation of innate and adaptive immunity and contribute to the pathophysiological alterations of CRS. The phenomena of epithelial-mesenchymal transition (EMT), mucosal remodeling, and autophagy observed in CRS offer some novel insights into the pathogenesis of this disease. In addition, existing treatment options targeting disorder of sinonasal epithelium can help to relieve the main symptoms associated with CRS to some extent.

Conclusion

The presence of a normal epithelium is fundamental for maintaining homeostasis in the nasal and paranasal sinuses. Here, we describe various aspects of the sinonasal epithelium and highlight the contributions of epithelial dysfunction to CRS pathogenesis. Our review provides sound evidence of the need for in-depth study of the pathophysiological alterations of this disease and for the development of novel epithelium-targeting alternative treatments.

The intestinal barrier in disorders of the central nervous system

The intestinal barrier, which primarily consists of a mucus layer, an epithelial barrier, and a gut vascular barrier, has a crucial role in health and disease by facilitating nutrient absorption and preventing the entry of pathogens. The intestinal barrier is in close contact with gut microbiota on its luminal side and with enteric neurons and glial cells on its tissue side. Mounting evidence now suggests that the intestinal barrier is compromised not only in digestive disorders, but also in disorders of the central nervous system (CNS), such as Parkinson's disease, autism spectrum disorder, depression, multiple sclerosis, and Alzheimer's disease. After providing an overview of the structure and functions of the intestinal barrier, we review existing preclinical and clinical studies supporting the notion that intestinal barrier dysfunction is present in neurological, neurodevelopmental, and psychiatric disorders. On the basis of this evidence, we discuss the mechanisms that possibly link gut barrier dysfunction and CNS disorders and the potential impact that evaluating enteric barriers in brain disorders could have on clinical practice, in terms of novel diagnostic and therapeutic strategies, in the near future.

Intestinal protein uptake and IgE-mediated food allergy

Food allergy is affecting 5-8% of young children and 2-4% of adults and seems to be increasing in prevalence. The cause of the increase in food allergy is largely unknown but proposed to be influenced by both environmental and lifestyle factors. Changes in intestinal barrier functions and increased uptake of dietary proteins have been suggested to have a great impact on food allergy. In this review, we aim to give an overview of the gastrointestinal digestion and intestinal barrier function and provide a more detailed description of intestinal protein uptake, including the various routes of epithelial transport, how it may be affected by both intrinsic and extrinsic factors, and the relation to food allergy. Further, we give an overview of in vitro, ex vivo and in vivo techniques available for evaluation of intestinal protein uptake and gut permeability in general. Proteins are digested by gastric, pancreatic and integral brush border enzymes in order to allow for sufficient nutritional uptake. Absorption and transport of dietary proteins across the epithelial layer is known to be dependent on the physicochemical properties of the proteins and their digestion fragments themselves, such as size, solubility and aggregation status. It is believed, that the greater an amount of intact protein or larger peptide fragments that is transported through the epithelial layer, and thus encountered by the mucosal immune system in the gut, the greater is the risk of inducing an adverse allergic response. Proteins may be absorbed across the epithelial barrier by means of various mechanisms, and studies have shown that a transcellular facilitated transport route unique for food allergic individuals are at play for transport of allergens, and that upon mediator release from mast cells an enhanced allergen transport via the paracellular route occurs. This is in contrast to healthy individuals where transcytosis through the enterocytes is the main route of protein uptake. Thus, knowledge on factors affecting intestinal barrier functions and methods for the determination of their impact on protein uptake may be useful in future allergenicity assessments and for development of future preventive and treatment strategies.

Mechanisms of macular edema

Macular edema is the pathological accumulation of fluid in the central retina. It is a complication of many retinal diseases, including diabetic retinopathy, retinal vascular occlusions and uveitis, among others. Macular edema causes decreased visual acuity and, when chronic or refractory, can cause severe and permanent visual impairment and blindness. In most instances, it develops due to dysregulation of the blood-retinal barrier which permits infiltration of the retinal tissue by proteins and other solutes that are normally retained in the blood. The increase in osmotic pressure in the tissue drives fluid accumulation. Current treatments include vascular endothelial growth factor blockers, corticosteroids, and non-steroidal anti-inflammatory drugs. These treatments target vasoactive and inflammatory mediators that cause disruption to the blood-retinal barrier. In this review, a clinical overview of macular edema is provided, mechanisms of disease are discussed, highlighting processes targeted by current treatments, and areas of opportunity for future research are identified.

Mycobacterium abscessus infection results in decrease of oxidative metabolism of lung airways cells and relaxation of the epithelial mucosal tight junctions

Mycobacterium abscessus complex is a group of environmental pathogens that recently have been isolated more from patients with underlying lung diseases, such and COPD, bronchiectasis, and cystic fibrosis. The mechanisms involved in the pathogenesis of these diseases have only recently been investigated. Infection is associated with biofilm formation on the airway mucosa, invasion of the mucosal epithelial cells and a time-dependent impairment of the integrity of the monolayer. Using electron microscopy, it was shown that Mycobacterium abscessus induced lesions of the cell surface structures. Tight junction proteins claudin-1 and occludin-1 have increased transcription in cells exposed to Mycobacterium abscessus, in contrast to cells exposed to Mycobacterium avium. Infection of A549 alveolar epithelial cells by Mycobacterium abscessus reduced the oxidative metabolism of the cell, without inducing necrosis. A transposon library screen identified mutants that do not alter the metabolism of the A549 cells.Once the bacterium crosses the epithelial barrier, it may encounter sub-epithelial macrophages. Select mutants were used for infection assays to determine their effects on membrane integrity. Translocated select mutants were attenuated in macrophages compared to wild type Mycobacterium abscessus. In summary, the dynamics of Mycobacterium abscessus infection appears to be different from other non-tuberculous mycobacteria (NTMs). Future studies will attempt to address the mechanism involved in airway membrane lesions.

Overview of junctional complexes during mammalian early embryonic development

Cell-cell junctions form strong intercellular connections and mediate communication between blastomeres during preimplantation embryonic development and thus are crucial for cell integrity, polarity, cell fate specification and morphogenesis. Together with cell adhesion molecules and cytoskeletal elements, intercellular junctions orchestrate mechanotransduction, morphokinetics and signaling networks during the development of early embryos. This review focuses on the structure, organization, function and expressional pattern of the cell-cell junction complexes during early embryonic development. Understanding the importance of dynamic junction formation and maturation processes will shed light on the molecular mechanism behind developmental abnormalities of early embryos during the preimplantation period.

Morphological control enables nanometer-scale dissection of cell-cell signaling complexes

Protein micropatterning enables robust control of cell positioning on electron-microscopy substrates for cryogenic electron tomography (cryo-ET). However, the combination of regulated cell boundaries and the underlying electron-microscopy substrate (EM-grids) provides a poorly understood microenvironment for cell biology. Because substrate stiffness and morphology affect cellular behavior, we devised protocols to characterize the nanometer-scale details of the protein micropatterns on EM-grids by combining cryo-ET, atomic force microscopy, and scanning electron microscopy. Measuring force displacement characteristics of holey carbon EM-grids, we found that their effective spring constant is similar to physiological values expected from skin tissues. Despite their apparent smoothness at light-microscopy resolution, spatial boundaries of the protein micropatterns are irregular at nanometer scale. Our protein micropatterning workflow provides the means to steer both positioning and morphology of cell doublets to determine nanometer details of punctate adherens junctions. Our workflow serves as the foundation for studying the fundamental structural changes governing cell-cell signaling.

Deoxynivalenol triggers porcine intestinal tight junction disorder: Insights from mitochondrial dynamics and mitophagy

Deoxynivalenol (DON) is universally detected trichothecene in most cereal commodities, which is considered as a major hazardous material for human and animal health. Intestine is the most vulnerable organ with higher concentration of DON than other organs, owing to the first defense barrier function to exogenous substances. However, the underling mechanisms about DON-induced intestinal toxicity remain poorly understood. Here, DON poisoning models of IPEC-J2 cells was established to explore adverse effect and the potential mechanism of DON-induced enterotoxicity. Results showed that DON exposure destroyed IPEC-J2 cells morphology. Results showed that DON exposure destroyed IPEC-J2 cells morphology. Intestinal epithelial barrier injury was caused by DON with increasing LDH release, decreasing cell viability as well decreasing tight junction protein expressions (Occludin, N-Cad, ZO-1, Claudin-1 and Claudin-3). Moreover, DON caused mitochondrial dysfunction by opening mitochondrial permeability transition pore and eliminating mitochondrial membrane potential. DON exposure upregulated protein and mRNA expression of mitochondrial fission factors (Drp1, Fis1, MIEF1 and MFF) and mitophagy factors (PINK1, Parkin and LC3), downregulated mitochondrial fusion factors (Mfn1, Mfn2, except OPA1), resulting in mitochondrial dynamics imbalance and mitophagy. Overall, these findings suggested that DON induced tight junction dysfunction in IPEC-J2 cells was related to mitochondrial dynamics-mediated mitophagy.

Diabetes causes NLRP3-dependent barrier dysfunction in mice with detrusor overactivity but not underactivity

Approximately half of the patients with diabetes develop diabetic bladder dysfunction (DBD). The initiation and progression of DBD is largely attributed to inflammation due to dysregulated glucose and the production of toxic metabolites that activate the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome. NLRP3 activation leads to the production and release of proinflammatory cytokines and causes urothelial pyroptosis, a form of programmed cell necrosis, which we hypothesize compromises urothelial barrier integrity. Here, we investigated how NLRP3-dependent inflammation impacts barrier function during the progression of diabetes using a type 1 diabetic female Akita mouse model that progresses from an early overactive to a late underactive detrusor phenotype at 15 and 30 wk, respectively. To determine the specific role of NLRP3, Akita mice were crossbred with mice lacking the NLRP3 gene. To determine barrier function, permeability to small molecules was assessed, ex vivo using Evans blue dye and in vivo using sulfo-NHS-biotin. Both ex vivo and in vivo permeabilities were increased in diabetic mice at 15 wk. Expression of uroplakin and tight junction components was also significantly downregulated at 15 wk. Interestingly, diabetic mice lacking the NLRP3 gene showed no evidence of barrier damage or downregulation of barrier genes and proteins. At the 30-wk time point, ex vivo and in vivo barrier damage as well as barrier component downregulation was no longer evident in diabetic mice, suggesting urothelial repair or remodeling occurs between the overactive and underactive stages of DBD. Collectively, these findings demonstrate the role of NLRP3-mediated inflammation in urothelial barrier damage associated with detrusor overactivity but not underactivity.NEW & NOTEWORTHY This is the first study to demonstrate that NLRP3-mediated inflammation is responsible for urothelial barrier damage in type 1 diabetic female Akita mice with an overactive bladder. Eliminating the NLRP3 gene in these diabetic mice prevented barrier damage as a result of diabetes. By the time female Akita mice develop an underactive phenotype, the urothelial barrier has been restored, suggesting that inflammation is a critical causative factor early in the development of diabetic bladder dysfunction.

How mechanisms of stem cell polarity shape the human cerebral cortex

Apical-basal progenitor cell polarity establishes key features of the radial and laminar architecture of the developing human cortex. The unique diversity of cortical stem cell populations and an expansion of progenitor population size in the human cortex have been mirrored by an increase in the complexity of cellular processes that regulate stem cell morphology and behaviour, including their polarity. The study of human cells in primary tissue samples and human stem cell-derived model systems (such as cortical organoids) has provided insight into these processes, revealing that protein complexes regulate progenitor polarity by controlling cell membrane adherence within appropriate cortical niches and are themselves regulated by cytoskeletal proteins, signalling molecules and receptors, and cellular organelles. Studies exploring how cortical stem cell polarity is established and maintained are key for understanding the features of human brain development and have implications for neurological dysfunction.

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.

Inflammation triggered by the NLRP3 inflammasome is a critical driver of diabetic bladder dysfunction

Diabetes is a rapidly expanding epidemic projected to affect as many as 1 in 3 Americans by 2050. This disease is characterized by devastating complications brought about high glucose and metabolic derangement. The most common of these complications is diabetic bladder dysfunction (DBD) and estimates suggest that 50-80% of patients experience this disorder. Unfortunately, the Epidemiology of Diabetes Interventions and Complications Study suggests that strict glucose control does not decrease ones risk for incontinence, although it does decrease the risk of other complications such as retinopathy, nephropathy and neuropathy. Thus, there is a significant unmet need to better understand DBD in order to develop targeted therapies to alleviate patient suffering. Recently, the research community has come to understand that diabetes produces a systemic state of low-level inflammation known as meta-inflammation and attention has focused on a role for the sterile inflammation-inducing structure known as the NLRP3 inflammasome. In this review, we will examine the evidence that NLRP3 plays a central role in inducing DBD and driving its progression towards an underactive phenotype.

ECM Substrates Impact RNAi Localization at Adherens Junctions of Colon Epithelial Cells

The extracellular matrix (ECM) plays crucial roles in tissue homeostasis. Abnormalities in ECM composition are associated with pathological conditions, such as fibrosis and cancer. These ECM alterations are sensed by the epithelium and can influence its behavior through crosstalk with other mechanosensitive complexes, including the adherens junctions (AJs). We have previously shown that the AJs, through their component PLEKHA7, recruit the RNAi machinery to regulate miRNA levels and function. We have particularly shown that the junctional localization of RNAi components is critical for their function. Here, we investigated whether different ECM substrates can influence the junctional localization of RNAi complexes. To do this, we plated colon epithelial Caco2 cells on four key ECM substrates found in the colon under normal or pathogenic conditions, namely laminin, fibronectin, collagen I, and collagen IV, and we examined the subcellular distribution of PLEKHA7, and of the key RNAi components AGO2 and DROSHA. Fibronectin and collagen I negatively impacted the junctional localization of PLEKHA7, AGO2, and DROSHA when compared to laminin. Furthermore, fibronectin, collagen I, and collagen IV disrupted interactions of AGO2 and DROSHA with their essential partners GW182 and DGCR8, respectively, both at AJs and throughout the cell. Combinations of all substrates with fibronectin also negatively impacted junctional localization of PLEKHA7 and AGO2. Additionally, collagen I triggered accumulation of DROSHA at tri-cellular junctions, while both collagen I and collagen IV resulted in DROSHA accumulation at basal areas of cell-cell contact. Altogether, fibronectin and collagens I and IV, which are elevated in the stroma of fibrotic and cancerous tissues, altered localization patterns and disrupted complex formation of PLEKHA7 and RNAi components. Combined with our prior studies showing that apical junctional localization of the PLEKHA7-RNAi complex is critical for regulating tumor-suppressing miRNAs, this work points to a yet unstudied mechanism that could contribute to epithelial cell transformation.

p115RhoGEF activates RhoA to support tight junction maintenance and remodeling

In vertebrates, epithelial cell-cell junctions must rapidly remodel to maintain barrier function as cells undergo dynamic shape-change events. Consequently, localized leaks sometimes arise within the tight junction (TJ) barrier, which are repaired by short-lived activations of RhoA, called "Rho flares." However, how RhoA is activated at leak sites remains unknown. Here we asked which guanine nucleotide exchange factor (GEF) localizes to TJs to initiate Rho activity at Rho flares. We find that p115RhoGEF locally activates Rho flares at sites of TJ loss. Knockdown of p115RhoGEF leads to diminished Rho flare intensity and impaired TJ remodeling. p115RhoGEF knockdown also decreases junctional active RhoA levels, thus compromising the apical actomyosin array and junctional complex. Furthermore, p115RhoGEF is necessary to promote local leak repair to maintain TJ barrier function. In all, our work demonstrates a central role for p115RhoGEF in activating junctional RhoA to preserve barrier function and direct local TJ remodeling.

Study on the Mechanism of Arsenic-Induced Lung Injury Based on SWATH Proteomics Technology

Chronic arsenic poisoning is a global health problem that affects millions of people, and studies have found that long-term ingestion of arsenic-containing compounds can lead to lung damage, but the exact mechanism is unknown. In this study, Sprague-Dawley (SD) rats were used as the research object, and the proteomic analysis method based on sequential window acquisition of all theoretical fragment ions (SWATH) was used to detect the changes in the expression levels of related proteins in the lung tissue of arsenic-exposed rats, and to explore the mechanism of arsenic compound-induced lung injury. The results showed that arsenic exposure resulted in the abnormal expression of collagen type III and proteins involved in metabolic, immune, and cellular processes, leading to the dysfunction of important pathways associated with these proteins, resulting in lung injury. It suggested that the underlying mechanism of arsenic-induced lung injury may be related to oxidative stress, immune injury, cell junction, and collagen type III. This result provides a new research idea for revealing the mechanism of lung injury caused by arsenic exposure.

Nucleation of cadherin clusters on cell-cell interfaces

Cadherins mediate cell-cell adhesion and help the cell determine its shape and function. Here we study collective cadherin organization and interactions within cell-cell contact areas, and find the cadherin density at which a 'gas-liquid' phase transition occurs, when cadherin monomers begin to aggregate into dense clusters. We use a 2D lattice model of a cell-cell contact area, and coarse-grain to the continuous number density of cadherin to map the model onto the Cahn-Hilliard coarsening theory. This predicts the density required for nucleation, the characteristic length scale of the process, and the number density of clusters. The analytical predictions of the model are in good agreement with experimental observations of cadherin clustering in epithelial tissues.

A pilot study to show that asymptomatic sexually transmitted infections alter the foreskin epithelial proteome

There is limited data on the role of asymptomatic STIs (aSTIs) on the risk of human immunodeficiency virus (HIV) acquisition in the male genital tract (MGT). The impact of foreskin removal on lowering HIV acquisition is well described, but molecular events leading to HIV acquisition are unclear. Here, in this pilot study, we show that asymptomatic urethral infection with Chlamydia trachomatis (CT) significantly impacts the foreskin proteome composition. We developed and optimized a shotgun liquid chromatography coupled tandem mass spectrometry (MS)-based proteomics approach and utilized this on foreskins collected at medical male circumcision (MMC) from 16 aSTI+ men and 10 age-matched STI- controls. We used a novel bioinformatic metaproteomic pipeline to detect differentially expressed (DE) proteins. Gene enrichment ontology analysis revealed proteins associated with inflammatory and immune activation function in both inner and outer foreskin from men with an aSTI. Neutrophil activation/degranulation and viral-evasion proteins were significantly enriched in foreskins from men with aSTI, whereas homotypic cell–cell adhesion proteins were enriched in foreskin tissue from men without an aSTI. Collectively, our data show that asymptomatic urethral sexually transmitted infections result in profound alterations in epithelial tissue that are associated with depletion of barrier integrity and immune activation.

Embryonic transcriptome unravels mechanisms and pathways underlying embryonic development with respect to muscle growth, egg production, and plumage formation in native and broiler chickens

Background: Muscle development, egg production, and plumage colors are different between native and broiler chickens. The study was designed to investigate why improved Aseel (PD4) is colorful, stronger, and grew slowly compared with the control broiler (CB).

Methods: A microarray was conducted using the 7th-day embryo (7EB) and 18th-day thigh muscle (18TM) of improved Aseel and broiler, respectively. Also, we have selected 24 Gallus gallus candidate reference genes from NCBI, and total RNA was isolated from the broiler, improved Aseel embryo tissues, and their expression profiles were studied by real-time quantitative PCR (qPCR). Furthermore, microarray data were validated with qPCR using improved Aseel and broiler embryo tissues.

Results: In the differential transcripts screening, all the transcripts obtained by microarray of slow and fast growth groups were screened by fold change ≥ 1 and false discovery rate (FDR) ≤ 0.05. In total, 8,069 transcripts were differentially expressed between the 7EB and 18TM of PD4 compared to the CB. A further analysis showed that a high number of transcripts are differentially regulated in the 7EB of PD4 (6,896) and fewer transcripts are differentially regulated (1,173) in the 18TM of PD4 compared to the CB. On the 7th^- and 18th-day PD4 embryos, 3,890, 3,006, 745, and 428 transcripts were up- and downregulated, respectively. The commonly up- and downregulated transcripts are 91 and 44 between the 7th- and 18th-day of embryos. In addition, the best housekeeping gene was identified. Furthermore, we validated the differentially expressed genes (DEGs) related to muscle growth, myostatin signaling and development, and fatty acid metabolism genes in PD4 and CB embryo tissues by qPCR, and the results correlated with microarray expression data.

Conclusion: Our study identified DEGs that regulate the myostatin signaling and differentiation pathway; glycolysis and gluconeogenesis; fatty acid metabolism; Jak-STAT, mTOR, and TGF-β signaling pathways; tryptophan metabolism; and PI3K-Akt signaling pathways in PD4. The results revealed that the gene expression architecture is present in the improved Aseel exhibiting embryo growth that will help improve muscle development, differentiation, egg production, protein synthesis, and plumage formation in PD4 native chickens. Our findings may be used as a model for improving the growth in Aseel as well as optimizing the growth in the broiler.

Adherens junction proteins on the move—From the membrane to the nucleus in intestinal diseases

The function and structure of the mammalian epithelial cell layer is maintained by distinct intercellular adhesion complexes including adherens junctions (AJs), tight junctions, and desmosomes. The AJ is most integral for stabilizing cell-cell adhesion and conserving the structural integrity of epithelial tissues. AJs are comprised of the transmembrane protein E-cadherin and cytoplasmic catenin cofactors (α, β, γ, and p120-catenin). One organ where malfunction of AJ is a major contributor to disease states is the mammalian intestine. In the intestine, cell-cell adhesion complexes work synergistically to maintain structural integrity and homeostasis of the epithelium and prevent its malfunction. Consequently, when AJ integrity is compromised in the intestinal epithelium, the ensuing homeostatic disruption leads to diseases such as inflammatory bowel disease and colorectal carcinoma. In addition to their function at the plasma membrane, protein components of AJs also have nuclear functions and are thus implicated in regulating gene expression and intracellular signaling. Within the nucleus, AJ proteins have been shown to interact with transcription factors such as TCF/LEF and Kaiso (ZBTB33), which converge on the canonical Wnt signaling pathway. The multifaceted nature of AJ proteins highlights their complexity in modulating homeostasis and emphasizes the importance of their subcellular localization and expression in the mammalian intestine. In this review, we summarize the nuclear roles of AJ proteins in intestinal tissues; their interactions with transcription factors and how this leads to crosstalk with canonical Wnt signaling; and how nuclear AJ proteins are implicated in intestinal homeostasis and disease.

Lipopolysaccharide downregulates the expression of ZO-1 protein through the Akt pathway

Background

Neonatal bacterial meningitis is a common neonatal disease with high morbidity, and can cause serious sequelae when left untreated. Escherichia coli is the common pathogen, and its endotoxin, lipopolysaccharide (LPS) can damage the endothelial cells, increasing the permeability of the blood-brain barrier (BBB), leading to intracranial inflammation. However, the specific mechanism of bacterial meningitis induced by LPS damaging BBB remains unclear. In this study, the mouse brain microvascular endothelial (bEND.3) cells were used as a research object to investigate whether LPS damage BBB through the PI3K/Akt pathway.

Methods

The bEND.3 cells were stimulated with different concentrations of LPS for 12 h, and the expression of tight junction proteins (ZO-1, claudin-5, occludin) was detected using western blotting. The cells were challenged with the same concentration of LPS (1ug/ml) across different timepoints (0, 2 h, 4 h, 6 h, 12 h, 24 h). Expression of TJ proteins and signal pathway molecules (PI3K, p-PI3K, Akt, p-Akt) were detected. The distribution of ZO-1 in bEND.3 cells were detected by immunofluorescence staining.

Results

A negative correlation is observed between ZO-1 and LPS concentration. Moreover, a reduced expression of ZO-1 was most significant under 1 ug/ml of LPS, and the difference was statistically significant (P < 0.05). Additionally, there is a negative correlation between ZO-1 and LPS stimulation time. Meanwhile, the expression of claudin-5 and occludin did not change significantly with the stimulation of LPS concentration and time. The immunofluorescence assay showed that the amount of ZO-1 on the surface of bEND.3 cells stimulated with LPS was significantly lower than that of the control group. After LPS stimulation, p-Akt protein increased at 2 h and peaked at 4 h. The titer of p-PI3K did not change significantly with time.

Conclusion

LPS can downregulate the expression of ZO-1; however, its effect on claudin-5 and occludin is minimal. Akt signal pathway may be involved in the regulation of ZO-1 expression induced by LPS in bEND.3 cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07752-1.