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

Pig-Derived Probiotic Bacillus tequilensis YB-2 Alleviates Intestinal Inflammation and Intestinal Barrier Damage in Colitis Mice by Suppressing the TLR4/NF-κB Signaling Pathway

The search for new probiotics has been regarded as an important approach to improving intestinal health in animals. Bacillus has many advantages, such as strong resistance to harmful external factors, wide distribution, and easy colonization of the intestine. Hence, this study aims to screen for a probiotic Bacillus strain that improves animal intestinal health and to elucidate its probiotic mechanism so as to provide probiotic resources for the development of feed-using probiotic formulations. In this research, a strain of Bacillus was isolated from adult pig feces and named B. tequilensis YB-2. In vitro probiotic experiments showed that B. tequilensis YB-2 had strong acid and bile salt resistance, indicating that this strain can customize in the intestine. To further explore the effect of B. tequilensis YB-2 upon animal intestinal health, DSS-induced murine colitis models were established, and the body weight, colonic morphology, inflammatory cytokines level, and intestinal-barrier- and TLR4/NF-κB-pathway-related protein were determined. The results showed that mice receiving drinking water with 3% DSS were found to develop colitis symptoms, including body weight loss and increased disease activity index (DAI); colon length and microvilli shedding were shortened; tight junctions were disrupted; goblet cells decreased; anti-inflammatory cytokines were inhibited; and pro-inflammatory cytokines and the TLR4/NF-κB signaling pathway were activated. Notably, orally received B. tequilensis YB-2 alleviated symptoms of DSS-induced colitis in mice. The above results indicated that B. tequilensis YB-2 was capable of improving colitis in mice by weakening inflammation and intestinal barrier damage, and its mechanism may involve the TLR4/NF-κB pathway. Overall, this research suggests that B. tequilensis YB-2 has the potential to serve as an animal feed additive to prevent intestinal inflammation.

Carbonic anhydrase IX: An atypical target for innovative therapies in cancer

Carbonic anhydrases (CAs), are metallo-enzymes implicated in several pathophysiological processes where tissue pH regulation is required. CA IX is a tumor-associated CA isoform induced by hypoxia and involved in the adaptation of tumor cells to acidosis. Indeed, several tumor-driving pathways can induce CA IX expression, and this in turn has been associated to cancer cells invasion and metastatic features as well as to induction of stem-like features, drug resistance and recurrence. After its functional and structural characterization CA IX targeting approaches have been developed to inhibit its activity in neoplastic tissues, and to date this field has seen an incredible acceleration in terms of therapeutic options and biological readouts. Small molecules inhibitors, hybrid/dual targeting drugs, targeting antibodies and adoptive (CAR-T based) cell therapy have been developed at preclinical level, whereas a sulfonamide CA IX inhibitor and an antibody entered Phase Ib/II clinical trials for the treatment and imaging of different solid tumors. Here recent advances on CA IX biology and pharmacology in cancer, and its therapeutic targeting will be discussed.

Synergy of gut microbiota and host genome in driving heterosis expression of chickens

Heterosis has been widely utilized in agricultural production. Despite over a century of extensive research, the underlying mechanisms of heterosis remain elusive. Most hypotheses and research have focused on the genetic basis of heterosis. However, the potential role of gut microbiota in heterosis has been largely ignored. Here, we carefully design a crossbreeding experiment with two distinct broiler breeds and conduct 16S rRNA amplicon and transcriptome sequencing to investigate the synergistic role of gut microbiota and host genes in driving heterosis. We find that the breast muscle weight of the hybrids exhibits a high heterosis, 6.28% higher than mid-parent value. A notable difference is observed in the composition and potential function of cecal microbiota between hybrids and their parents. Over 90% of the differentially colonized microbiota and differentially expressed genes exhibit nonadditive patterns. Integrative analyses uncover associations between nonadditive genes and nonadditive microbiota, including a connection between the expression of cellular signaling pathway and metabolism-related genes and the abundance of Odoribacter, Oscillibacter, and Alistipes in hybrids. Moreover, higher abundances of these microbiota are related to better meat yield. In summary, these findings highlight the importance of gut microbiota in heterosis, serving as crucial factors that modulate heterosis expression in chickens.

The role of the gut microbiome in disorders of gut-brain interaction

Disorders of Gut-Brain Interaction (DGBI) are widely prevalent and commonly encountered in gastroenterology practice. While several peripheral and central mechanisms have been implicated in the pathogenesis of DGBI, a recent body of work suggests an important role for the gut microbiome. In this review, we highlight how gut microbiota and their metabolites affect physiologic changes underlying symptoms in DGBI, with a particular focus on their mechanistic influence on GI transit, visceral sensitivity, intestinal barrier function and secretion, and CNS processing. This review emphasizes the complexity of local and distant effects of microbial metabolites on physiological function, influenced by factors such as metabolite concentration, duration of metabolite exposure, receptor location, host genetics, and underlying disease state. Large-scale in vitro work has elucidated interactions between host receptors and the microbial metabolome but there is a need for future research to integrate such preclinical findings with clinical studies. The development of novel, targeted therapeutic strategies for DGBI hinges on a deeper understanding of these metabolite-host interactions, offering exciting possibilities for the future of treatment of DGBI.

Luteolin-7-O-β-d-Glucuronide Attenuated Cerebral Ischemia/Reperfusion Injury: Involvement of the Blood-Brain Barrier

Ischemic stroke is a common cerebrovascular disease with high mortality, high morbidity, and high disability. Cerebral ischemia/reperfusion injury seriously affects the quality of life of patients. Luteolin-7-O-β-d-glucuronide (LGU) is a major active flavonoid compound extracted from Ixeris sonchifolia (Bge.) Hance, a Chinese medicinal herb mainly used for the treatment of coronary heart disease, angina pectoris, cerebral infarction, etc. In the present study, the protective effect of LGU on cerebral ischemia/reperfusion injury was investigated in an oxygen-glucose deprivation/reoxygenation (OGD/R) neuronal model and a transient middle cerebral artery occlusion (tMCAO) rat model. In in vitro experiments, LGU was found to improve the OGD/R-induced decrease in neuronal viability effectively by the MTT assay. In in vivo experiments, neurological deficit scores, infarction volume rates, and brain water content rates were improved after a single intravenous administration of LGU. These findings suggest that LGU has significant protective effects on cerebral ischemia/reperfusion injury in vitro and in vivo. To further explore the potential mechanism of LGU on cerebral ischemia/reperfusion injury, we performed a series of tests. The results showed that a single administration of LGU decreased the content of EB and S100B and ameliorated the abnormal expression of tight junction proteins ZO-1 and occludin and metalloproteinase MMP-9 in the ischemic cerebral cortex of the tMCAO 24-h injury model. In addition, LGU also improved the tight junction structure between endothelial cells and the degree of basement membrane degradation and reduced the content of TNF-α and IL-1β in the brain tissue. Thereby, LGU attenuated cerebral ischemia/reperfusion injury by improving the permeability of the blood-brain barrier. The present study provides new insights into the therapeutic potential of LGU in cerebral ischemia.

Intestinal absorption of bioactive oligopeptides: paracellular transport and tight junction modulation

Bioactive oligopeptides have gained increasing attention due to their diverse physiological functions, and these can be transported into the vasculature via transcellular and paracellular pathways. Among these, paracellular transport through the intercellular space is a passive diffusion process without energy consumption. It is currently the most frequently reported absorption route for food-derived bioactive oligopeptides. Previous work has demonstrated that paracellular pathways are mainly controlled by tight junctions, but the mechanism by which they regulate paracellular absorption of bioactive oligopeptides remains unclear. In this review, we summarized the composition of paracellular pathways across the intercellular space and elaborated on the paracellular transport mechanism of bioactive oligopeptides in terms of the interaction between oligopeptides and tight junction proteins, the protein expression level of tight junctions, the signaling pathways regulating intestinal permeability, and the properties of oligopeptides themselves. These findings contribute to a more profound understanding of the paracellular absorption of bioactive oligopeptides.

Altering Cell Junctional Tension in Spheroids through E-Cadherin Engagement Modulation

Cadherin-mediated tension at adherens junctions (AJs) is fundamental for cell-cell adhesion and maintaining epithelial integrity. Despite the importance of manipulating AJs to dissect cell-cell interactions, existing three-dimensional (3D) multicellular models have not adequately addressed the precise manipulation of these junctions. To fill this gap, we introduce E-cadherin-modified tension gauge tethers (TGTs) at the junctions within spheroids. The system enables both quantification and modulation of junctional tension with specific DNA triggers. Using rupture-induced fluorescence, we successfully measure mechanical forces in 3D spheroids. Furthermore, mechanically strong TGTs can maintain normal E-cadherin-mediated adhesion. Employing toehold-mediated strand displacement allowed us to disrupt E-cadherin-specific cell-cell adhesion, consequently altering intracellular tension within the spheroids. Our methodology offers a robust and precise way to manipulate cell-cell adhesion and intracellular mechanics in spheroid models.

Multiaction Pt(IV) Prodrugs Releasing Cisplatin and Dasatinib Are Potent Anticancer and Anti-Invasive Agents Displaying Synergism between the Two Drugs

Herein, we describe the general design, synthesis, characterization, and biological activity of new multitargeting Pt(IV) prodrugs that combine antitumor cisplatin and dasatinib, a potent inhibitor of Src kinase. These prodrugs exhibit impressive antiproliferative and anti-invasive activities in tumor cell lines in both two-dimensional (2D) monolayers of cell cultures and three-dimensional (3D) spheroids. We show that the cisplatin moiety and dasatinib in the investigated Pt(IV) complexes are both involved in the mechanism of action in MCF7 breast cancer cells and act synergistically. Thus, combining dasatinib and cisplatin into one molecule, compared to using individual components in a mix, may bring several advantages, such as significantly higher activity in cancer cell lines and higher selectivity for tumor cells. Most importantly, Pt(IV)-dasatinib complexes hold significant promise for potential anticancer therapies by targeting epithelial-mesenchymal transition, thus preventing the spread and metastasis of tumors, a value unachievable by a simple combination of both individual components.

The umbrella cell keratin network: organization as a tile-like mesh, formation of a girded layer in response to bladder filling, and dependence on the plectin cytolinker

The keratin cytoskeleton and associated desmosomes contribute to the mechanical stability of epithelial tissues, but their organization in bladder umbrella cells and their responses to bladder filling are poorly understood. Using super-resolution confocal microscopy, along with 3D image reconstruction and platinum replica electron microscopy, we observed that the apical keratin network of umbrella cells was organized as a dense tile-like mesh comprised of tesserae bordered on their edges by cortical actin filaments, filled with woven keratin filaments, and crosslinked by plectin. A band of keratin was also observed at the cell periphery that was linked to the junction-associated actin ring by plectin. During bladder filling, the junction-localized desmosomal necklace expanded, and a subjacent girded layer was formed that linked the keratin network to desmosomes, including those at the umbrella cell-intermediate cell interface. Disruption of plectin led to focal keratin network dissolution, loss of the junction-associated band of keratin, perturbation of tight junction continuity, and loss of cell-cell cohesion. Our studies reveal a novel tile-like organization of the umbrella cell keratin cytoskeleton that is dependent on plectin, that reorganizes in response to bladder filling, and that likely serves to maintain umbrella cell continuity in the face of mechanical distension.

Biophysics of claudin proteins in tight junction architecture: Three decades of progress

Tight junctions are cell-cell adhesion complexes that act as gatekeepers of the paracellular space. Formed by several transmembrane proteins, the claudin family performs the primary gate-keeping function. The claudin proteins form charge and size-selective diffusion barriers to maintain homeostasis across endothelial and epithelial tissue. Of the 27 known claudins in mammals, some are known to seal the paracellular space, while others provide selective permeability. The differences in permeability arise due to the varying expression levels of claudins in each tissue. The tight junctions are observed as strands in freeze-fracture electron monographs; however, at the molecular level, tight junction strands form when multiple claudin proteins assemble laterally (cis assembly) within a cell and head-on (trans assembly) with claudins of the adjacent cell in a zipper-like architecture, closing the gap between the neighboring cells. The disruption of tight junctions caused by changing claudin expression levels or mutations can lead to diseases. Therefore, knowledge of the molecular architecture of the tight junctions and how that is tied to tissue-specific function is critical for fighting diseases. Here, we review the current understanding of the tight junctions accrued over the last three decades from experimental and computational biophysics perspectives.

The Impact of Different Dietary Ratios of Soluble Carbohydrate-to-Neutral Detergent Fiber on Rumen Barrier Function and Inflammation in Dumont Lambs

Appropriate soluble carbohydrate (SCHO)-to-NDF ratios in the diet are essential for rumen health. The effects of different SCHO-to-NDF ratios (1.0, 1.5, and 2.0) on rumen barrier function and inflammation in Dumont lambs (n = 18, 6 replicates per treatment) was investigated. The SCHO:NDF ratio was altered by replacing the forage (Leynus chinensis) with corn grain. With an increase in the proportion of SCHO, the final body weight (FBW), average daily gain (ADG), soluble carbohydrate intake (SCHOI), and LPS level increased; and the neutral detergent fiber intake (NDFI), ruminal papillae height, papillae area, and pH decreased (p < 0.05, plin < 0.05). The medium CHO:NDF group had increased claudin-1 mRNA (p < 0.05, plin = 0.005, pquad = 0.003) and protein (p < 0.05, pquad < 0.001) levels; the high CHO:NDF group had increased occludin mRNA and protein (p < 0.05, plin = 0.001) levels. The level of the anti-inflammatory cytokine IL-10 was significantly greater in the medium CHO:NDF group than in the high CHO:NDF group (p < 0.05, pquad < 0.001). With an increase in the ratio of SCHO, the mRNA level and concentration of the proinflammatory cytokines IL-1β, IL-6, and TNF-α linearly increased (p < 0.05, plin < 0.05), and those in the high CHO:NDF group were significantly greater than those in the low CHO:NDF group. The levels of phosphorylated p65 (plin = 0.003), IκB-α (plin < 0.001), and JNK (plin = 0.001) increased linearly, and those in the high CHO:NDF group were significantly greater than those in the other two groups (p < 0.05). Therefore, when the SCHO-to-NDF ratio was increased to 1.5, the rumen epithelium was not affected, but when the ratio was increased to 2.0, NF-κB and MAPK were activated in the rumen epithelium, leading to impaired barrier function and inflammation. The suitable NFC:NDF ratio for the short-term fattening of Dumont lambs was found to be 1.50.

VEGF-induced Nrdp1 deficiency in vascular endothelial cells promotes cancer metastasis by degrading vascular basement membrane

Vascular endothelial cells (VECs) are key players in the formation of neovessels and tumor metastasis, the ultimate cause of the majority of cancer-related human death. However, the crosstalk between VECs and metastasis remain greatly elusive. Based on our finding that tumor-associated VECs present significant decrease of Nrdp1 protein which is closely correlated with higher metastatic probability, herein we show that the conditional medium from hypoxia-incubated cancer cells induces extensive Nrdp1 downregulation in human and mouse VECs by vascular endothelial growth factor (VEGF), which activates CHIP, followed by Nrdp1 degradation in ubiquitin-proteasome-dependent way. More importantly, lung metastases of cancer cells significantly increase in conditional VECs Nrdp1 knockout mice. Mechanically, Nrdp1 promotes degradation of Fam20C, a secretory kinase involved in phosphorylating numerous secreted proteins. Reciprocally, deficiency of Nrdp1 in VECs (ecNrdp1) results in increased secretion of Fam20C, which induces degradation of extracellular matrix and disrupts integrity of vascular basement membrane, thus driving tumor metastatic dissemination. In addition, specific overexpression of ecNrdp1 by Nrdp1-carrying adeno-associated virus or chemical Nrdp1 activator ABPN efficiently mitigates tumor metastasis in mice. Collectively, we explore a new mechanism for VEGF to enhance metastasis and role of Nrdp1 in maintaining the integrity of vascular endothelium, suggesting that ecNrdp1-mediated signaling pathways might become potential target for anti-metastatic therapies.

Biophysical perspectives to understanding cancer-associated fibroblasts

The understanding of cancer has evolved significantly, with the tumor microenvironment (TME) now recognized as a critical factor influencing the onset and progression of the disease. This broader perspective challenges the traditional view that cancer is primarily caused by mutations, instead emphasizing the dynamic interaction between different cell types and physicochemical factors within the TME. Among these factors, cancer-associated fibroblasts (CAFs) command attention for their profound influence on tumor behavior and patient prognoses. Despite their recognized importance, the biophysical and mechanical interactions of CAFs within the TME remain elusive. This review examines the distinctive physical characteristics of CAFs, their morphological attributes, and mechanical interactions within the TME. We discuss the impact of mechanotransduction on CAF function and highlight how these cells communicate mechanically with neighboring cancer cells, thereby shaping the path of tumor development and progression. By concentrating on the biomechanical regulation of CAFs, this review aims to deepen our understanding of their role in the TME and to illuminate new biomechanical-based therapeutic strategies.

Biomarkers of epithelial-mesenchymal transition: E-cadherin and beta-catenin in malignant transformation of oral lesions

Objective

Detecting oral lesions at high risk of becoming cancer may enable early interventions to prevent oral cancer. The diagnosis of dysplasia in an oral lesion is used to predict this risk but is subject to interobserver and intraobserver variability. Studying biomarkers or molecular markers that reflect underlying molecular alterations can serve as an additional and objective method of risk assessment. E-cadherin and beta-catenin, molecular markers of epithelial-mesenchymal transition (EMT), potentially contribute to early malignant progression in oral tissue. This narrative review provides an overview of EMT, its relation to oral cancer, and the interaction among E-cadherin, beta-catenin, and the Wnt pathway in malignant progression of oral tissue.

Methods

Full-text literature on EMT, E-cadherin, beta-catenin, oral epithelial dysplasia, and oral cancer was retrieved from PubMed and Google Scholar.

Results

Sixty original research articles, reviews, and consensus statements were selected for review.

Discussion

EMT, a biological mechanism characterized by epithelial and mesenchymal changes, can contribute to cancer development. Molecular markers of EMT including TWIST, vimentin, and N-cadherin may serve as prognostic markers of oral cancer. Dependent on Wnt pathway activity and the loss of membranous E-cadherin, E-cadherin and beta-catenin can play various roles along the spectrum of malignant progression, including tumour inhibition, early tumour progression, and late-stage tumour progression. Cross-sectional immunohistochemical research has found changes in expression patterns of E-cadherin and beta-catenin from normal oral tissue, oral epithelial dysplasia, to oral squamous cell carcinoma.

Conclusion

Future research should explore the longitudinal role of EMT markers in predicting malignant progression in oral tissue.

Discrete network models of endothelial cells and their interactions with the substrate

Endothelial cell monolayers line the inner surfaces of blood and lymphatic vessels. They are continuously exposed to different mechanical loads, which may trigger mechanobiological signals and hence play a role in both physiological and pathological processes. Computer-based mechanical models of cells contribute to a better understanding of the relation between cell-scale loads and cues and the mechanical state of the hosting tissue. However, the confluency of the endothelial monolayer complicates these approaches since the intercellular cross-talk needs to be accounted for in addition to the cytoskeletal mechanics of the individual cells themselves. As a consequence, the computational approach must be able to efficiently model a large number of cells and their interaction. Here, we simulate cytoskeletal mechanics by means of molecular dynamics software, generally suitable to deal with large, locally interacting systems. Methods were developed to generate models of single cells and large monolayers with hundreds of cells. The single-cell model was considered for a comparison with experimental data. To this end, we simulated cell interactions with a continuous, deformable substrate, and computationally replicated multistep traction force microscopy experiments on endothelial cells. The results indicate that cell discrete network models are able to capture relevant features of the mechanical behaviour and are thus well-suited to investigate the mechanics of the large cytoskeletal network of individual cells and cell monolayers.

Current status and advances to improving drug delivery in diffuse intrinsic pontine glioma

Diffuse midline glioma (DMG), including tumors diagnosed in the brainstem (diffuse intrinsic pontine glioma - DIPG), is the primary cause of brain tumor-related death in pediatric patients. DIPG is characterized by a median survival of <12 months from diagnosis, harboring the worst 5-year survival rate of any cancer. Corticosteroids and radiation are the mainstay of therapy; however, they only provide transient relief from the devastating neurological symptoms. Numerous therapies have been investigated for DIPG, but the majority have been unsuccessful in demonstrating a survival benefit beyond radiation alone. Although many barriers hinder brain drug delivery in DIPG, one of the most significant challenges is the blood-brain barrier (BBB). Therapeutic compounds must possess specific properties to enable efficient passage across the BBB. In brain cancer, the BBB is referred to as the blood-brain tumor barrier (BBTB), where tumors disrupt the structure and function of the BBB, which may provide opportunities for drug delivery. However, the biological characteristics of the brainstem's BBB/BBTB, both under normal physiological conditions and in response to DIPG, are poorly understood, which further complicates treatment. Better characterization of the changes that occur in the BBB/BBTB of DIPG patients is essential, as this informs future treatment strategies. Many novel drug delivery technologies have been investigated to bypass or disrupt the BBB/BBTB, including convection enhanced delivery, focused ultrasound, nanoparticle-mediated delivery, and intranasal delivery, all of which are yet to be clinically established for the treatment of DIPG. Herein, we review what is known about the BBB/BBTB and discuss the current status, limitations, and advances of conventional and novel treatments to improving brain drug delivery in DIPG.

The New Paradigm: The Role of Proteins and Triggers in the Evolution of Allergic Asthma

Epithelial barrier damage plays a central role in the development and maintenance of allergic inflammation. Rises in the epithelial barrier permeability of airways alter tissue homeostasis and allow the penetration of allergens and other external agents. Different factors contribute to barrier impairment, such as eosinophilic infiltration and allergen protease action-eosinophilic cationic proteins' effects and allergens' proteolytic activity both contribute significantly to epithelial damage. In the airways, allergen proteases degrade the epithelial junctional proteins, allowing allergen penetration and its uptake by dendritic cells. This increase in allergen-immune system interaction induces the release of alarmins and the activation of type 2 inflammatory pathways, causing or worsening the main symptoms at the skin, bowel, and respiratory levels. We aim to highlight the molecular mechanisms underlying allergenic protease-induced epithelial barrier damage and the role of immune response in allergic asthma onset, maintenance, and progression. Moreover, we will explore potential clinical and radiological biomarkers of airway remodeling in allergic asthma patients.

The Basic Requirement of Tight Junction Proteins in Blood-Brain Barrier Function and Their Role in Pathologies

This review addresses the role of tight junction proteins at the blood-brain barrier (BBB). Their expression is described, and their role in physiological and pathological processes at the BBB is discussed. Based on this, new approaches are depicted for paracellular drug delivery and diagnostics in the treatment of cerebral diseases. Recent data provide convincing evidence that, in addition to its impairment in the course of diseases, the BBB could be involved in the aetiology of CNS disorders. Further progress will be expected based on new insights in tight junction protein structure and in their involvement in signalling pathways.

Unraveling the Role of the Blood-Brain Barrier in the Pathophysiology of Depression: Recent Advances and Future Perspectives

Depression is a highly prevalent psychological disorder characterized by persistent dysphoria, psychomotor retardation, insomnia, anhedonia, suicidal ideation, and a remarkable decrease in overall well-being. Despite the prevalence of accessible antidepressant therapies, many individuals do not achieve substantial improvement. Understanding the multifactorial pathophysiology and the heterogeneous nature of the disorder could lead the way toward better outcomes. Recent findings have elucidated the substantial impact of compromised blood-brain barrier (BBB) integrity on the manifestation of depression. BBB functions as an indispensable defense mechanism, tightly overseeing the transport of molecules from the periphery to preserve the integrity of the brain parenchyma. The dysfunction of the BBB has been implicated in a multitude of neurological disorders, and its disruption and consequent brain alterations could potentially serve as important factors in the pathogenesis and progression of depression. In this review, we extensively examine the pathophysiological relevance of the BBB and delve into the specific modifications of its components that underlie the complexities of depression. A particular focus has been placed on examining the effects of peripheral inflammation on the BBB in depression and elucidating the intricate interactions between the gut, BBB, and brain. Furthermore, this review encompasses significant updates on the assessment of BBB integrity and permeability, providing a comprehensive overview of the topic. Finally, we outline the therapeutic relevance and strategies based on BBB in depression, including COVID-19-associated BBB disruption and neuropsychiatric implications. Understanding the comprehensive pathogenic cascade of depression is crucial for shaping the trajectory of future research endeavors.

An actomyosin network organizes niche morphology and responds to feedback from recruited stem cells

Stem cells often rely on signals from a niche, which in many tissues adopts a precise morphology. What remains elusive is how niches are formed, and how morphology impacts function. To address this, we leverage the Drosophila gonadal niche, which affords genetic tractability and live-imaging. We have previously shown mechanisms dictating niche cell migration to their appropriate position within the gonad, and the resultant consequences on niche function. Here, we show that once positioned, niche cells robustly polarize filamentous actin (F-actin) and Non-muscle Myosin II (MyoII) towards neighboring germ cells. Actomyosin tension along the niche periphery generates a highly reproducible smoothened contour. Without contractility, niches are misshapen and exhibit defects in their ability to regulate germline stem cell behavior. We additionally show that germ cells aid in polarizing MyoII within niche cells, and that extrinsic input is required for niche morphogenesis and function. Our work reveals a feedback mechanism where stem cells shape the niche that guides their behavior.

E-cadherin interacts with EGFR resulting in hyper-activation of ERK in multiple models of breast cancer

The loss of intercellular adhesion molecule E-cadherin is a hallmark of the epithelial-mesenchymal transition (EMT), during which tumor cells transition into an invasive phenotype. Accordingly, E-cadherin has long been considered a tumor suppressor gene; however, E-cadherin expression is paradoxically correlated with breast cancer survival rates. Using novel multi-compartment organoids and multiple in vivo models, we show that E-cadherin promotes a hyper-proliferative phenotype in breast cancer cells via interaction with the transmembrane receptor EGFR. The E-cad and EGFR interaction results in activation of the MEK/ERK signaling pathway, leading to a significant increase in proliferation via activation of transcription factors, including c-Fos. Pharmacological inhibition of MEK activity in E-cadherin positive breast cancer significantly decreases both tumor growth and macro-metastasis in vivo. This work provides evidence for a novel role of E-cadherin in breast tumor progression and identifies a new target to treat hyper-proliferative E-cadherin-positive breast tumors, thus providing the foundation to utilize E-cadherin as a biomarker for specific therapeutic success.

NHE3 inhibitor tenapanor maintains intestinal barrier function, decreases visceral hypersensitivity, and attenuates TRPV1 signaling in colonic sensory neurons

The pathogenesis of irritable bowel syndrome (IBS) is multifactorial, characterized in part by increased intestinal permeability, and visceral hypersensitivity. Increased permeability is associated with IBS severity and abdominal pain. Tenapanor is FDA-approved for the treatment of IBS with constipation (IBS-C) and has demonstrated improvements in bowel motility and a reduction in IBS-related pain; however, the mechanism by which tenapanor mediates these functions remains unclear. Here, the effects of tenapanor on colonic pain signaling and intestinal permeability were assessed through behavioral, electrophysiological, and cell culture experiments. Intestinal motility studies in rats and humans demonstrated that tenapanor increased luminal sodium and water retention and gastrointestinal transit versus placebo. A significantly reduced visceral motor reflex (VMR) to colonic distension was observed with tenapanor treatment versus vehicle in two rat models of visceral hypersensitivity (neonatal acetic acid sensitization and partial restraint stress; both P < 0.05), returning VMR responses to that of nonsensitized controls. Whole cell voltage patch-clamp recordings of retrogradely labeled colonic dorsal root ganglia (DRG) neurons from sensitized rats found that tenapanor significantly reduced DRG neuron hyperexcitability to capsaicin versus vehicle (P < 0.05), an effect not mediated by epithelial cell secretions. Tenapanor also attenuated increases in intestinal permeability in human colon monolayer cultures caused by incubation with proinflammatory cytokines (P < 0.001) or fecal supernatants from patients with IBS-C (P < 0.005). These results support a model in which tenapanor reduces IBS-related pain by strengthening the intestinal barrier, thereby decreasing permeability to macromolecules and antigens and reducing DRG-mediated pain signaling.NEW & NOTEWORTHY A series of nonclinical experiments support the theory that tenapanor inhibits IBS-C-related pain by strengthening the intestinal barrier. Tenapanor treatment reduced visceral motor responses to nonsensitized levels in two rat models of hypersensitivity and reduced responses to capsaicin in sensitized colonic nociceptive dorsal root ganglia neurons. Intestinal permeability experiments in human colon monolayer cultures found that tenapanor attenuates increases in permeability induced by either inflammatory cytokines or fecal supernatants from patients with IBS-C.

Serine protease Rv2569c facilitates transmission of Mycobacterium tuberculosis via disrupting the epithelial barrier by cleaving E-cadherin

Epithelial cells function as the primary line of defense against invading pathogens. However, bacterial pathogens possess the ability to compromise this barrier and facilitate the transmigration of bacteria. Nonetheless, the specific molecular mechanism employed by Mycobacterium tuberculosis (M.tb) in this process is not fully understood. Here, we investigated the role of Rv2569c in M.tb translocation by assessing its ability to cleave E-cadherin, a crucial component of cell-cell adhesion junctions that are disrupted during bacterial invasion. By utilizing recombinant Rv2569c expressed in Escherichia coli and subsequently purified through affinity chromatography, we demonstrated that Rv2569c exhibited cell wall-associated serine protease activity. Furthermore, Rv2569c was capable of degrading a range of protein substrates, including casein, fibrinogen, fibronectin, and E-cadherin. We also determined that the optimal conditions for the protease activity of Rv2569c occurred at a temperature of 37°C and a pH of 9.0, in the presence of MgCl2. To investigate the function of Rv2569c in M.tb, a deletion mutant of Rv2569c and its complemented strains were generated and used to infect A549 cells and mice. The results of the A549-cell infection experiments revealed that Rv2569c had the ability to cleave E-cadherin and facilitate the transmigration of M.tb through polarized A549 epithelial cell layers. Furthermore, in vivo infection assays demonstrated that Rv2569c could disrupt E-cadherin, enhance the colonization of M.tb, and induce pathological damage in the lungs of C57BL/6 mice. Collectively, these results strongly suggest that M.tb employs the serine protease Rv2569c to disrupt epithelial defenses and facilitate its systemic dissemination by crossing the epithelial barrier.

EspP2 Regulates the Adhesion of Glaesserella parasuis via Rap1 Signaling Pathway

Different levels of EspP2 expression are seen in strains of Glaesserella parasuis with high and low pathogenicity. As a potential virulence factor for G. parasuis, the pathogenic mechanism of EspP2 in infection of host cells is not clear. To begin to elucidate the effect of EspP2 on virulence, we used G. parasuis SC1401 in its wild-type form and SC1401, which was made EspP2-deficient. We demonstrated that EspP2 causes up-regulation of claudin-1 and occludin expression, thereby promoting the adhesion of G. parasuis to host cells; EspP2-deficiency resulted in significantly reduced adhesion of G. parasuis to cells. Transcriptome sequencing analysis of EspP2-treated PK15 cells revealed that the Rap1 signaling pathway is stimulated by EspP2. Blocking this pathway diminished occludin expression and adhesion. These results indicated that EspP2 regulates the adhesion of Glaesserella parasuis via Rap1 signaling pathway.

Primary HIV infection features colonic damage and neutrophil inflammation yet containment of microbial translocation

INTRODUCTION

Impairment of the gastrointestinal barrier leads to microbial translocation and peripheral immune activation, which are linked to disease progression. Data in the setting of primary HIV/SIV infection suggest that gut barrier damage is one of the first events of the pathogenic cascade, preceding mucosal immune dysfunction and microbial translocation. We assessed gut structure and immunity as well as microbial translocation in acutely and chronically-infected, combination antiretroviral therapy (cART)-naive individuals.

METHODS

Fifteen people with primary HIV infection (P-HIV) and 13 with chronic HIV infection (C-HIV) c-ART-naive participants were cross-sectionally studied. Gut biopsies were analysed in terms of gut reservoirs (total, integrated and unintegrated HIV DNA); tight junction proteins (E-cadherin, Zonula Occludens-1), CD4 + expression, neutrophil myeloperoxidase (histochemical staining); collagen deposition (Masson staining). Flow cytometry was used to assess γδ T-cell frequency (CD3 + panγδ+Vδ1+/Vδ2+). In plasma, we measured microbial translocation (LPS, sCD14, EndoCAb) and gut barrier function (I-FABP) markers (ELISA).

RESULTS

P-HIV displayed significantly higher tissue HIV DNA, yet neutrophil infiltration and collagen deposition in the gut were similar in the two groups. In contrast, microbial translocation markers were significantly lower in P-HIV compared with C-HIV. A trend to higher mucosal E-cadherin, and gut γδ T-cells was also observed in P-HIV.

CONCLUSION

Early HIV infection features higher HIV DNA in the gut, yet comparable mucosal alterations to those observed in chronic infection. In contrast, microbial translocation is contained in primary HIV infection, likely because of a partial preservation of E-cadherin and mucosal immune subsets, namely γδ T-cells.

A sustainable strategy for generating highly stable human skin equivalents based on fish collagen

Tissue engineered skin equivalents are increasingly recognized as potential alternatives to traditional skin models such as human ex vivo skin or animal skin models. However, most of the currently investigated human skin equivalents (HSEs) are constructed using mammalian collagen which can be expensive and difficult to extract. Fish skin is a waste product produced by fish processing industries and identified as a cost-efficient and sustainable source of type I collagen. In this work, we describe a method for generating highly stable HSEs based on fibrin fortified tilapia fish collagen. The fortified fish collagen (FFC) formulation is optimized to enable reproducible fabrication of full-thickness HSEs that undergo limited contraction, facilitating the incorporation of human donor-derived skin cells and formation of biomimetic dermal and epidermal layers. The morphology and barrier function of the FFC HSEs are compared with a commercial skin model and validated with immunohistochemical staining and transepithelial electrical resistance testing. Finally, the potential of a high throughput screening platform with FFC HSE is explored by scaling down its fabrication to 96-well format.

The Scribble/SGEF/Dlg1 complex regulates the stability of apical junctions in epithelial cells

SGEF, a RhoG specific GEF, can form a ternary complex with the Scribble polarity complex proteins Scribble and Dlg1, which regulates the formation and maintenance of adherens junctions and barrier function of epithelial cells. Notably, silencing SGEF results in a dramatic downregulation of the expression of both E-cadherin and ZO-1. However, the molecular mechanisms involved in the regulation of this pathway are not known. Here, we describe a novel signaling pathway governed by the Scribble/SGEF/Dlg1 complex. Our results show that an intact ternary complex is required to maintain the stability of the apical junctions, the expression of ZO-1, and TJ permeability. In contrast, only SGEF is necessary to regulate E-cadherin expression. The absence of SGEF destabilizes the E-cadherin/catenin complex at the membrane, triggering a positive feedback loop that exacerbates the phenotype through the repression of E-cadherin transcription in a process that involves the internalization of E-cadherin by endocytosis, β-catenin signaling and the transcriptional repressor Slug.

RTCB deficiency triggers colitis in mice by influencing the NF-κB and Wnt/β-catenin signaling pathways

RNA terminal phosphorylase B (RTCB) has been shown to play a significant role in multiple physiological processes. However, the specific role of RTCB in the mouse colon remains unclear. In this study, we employ a conditional knockout mouse model to investigate the effects of RTCB depletion on the colon and the potential molecular mechanisms. We assess the efficiency and phenotype of Rtcb knockout using PCR, western blot analysis, histological staining, and immunohistochemistry. Compared with the control mice, the Rtcb-knockout mice exhibit compromised colonic barrier integrity and prominent inflammatory cell infiltration. In the colonic tissues of Rtcb-knockout mice, the protein levels of TNF-α, IL-8, and p-p65 are increased, whereas the levels of IKKβ and IκBα are decreased. Moreover, the level of GSK3β is increased, whereas the levels of Wnt3a, β-catenin, and LGR5 are decreased. Collectively, our findings unveil a close association between RTCB and colonic tissue homeostasis and demonstrate that RTCB deficiency can lead to dysregulation of both the NF-κB and Wnt/β-catenin signaling pathways in colonic cells.

Vascular leak in sepsis: physiological basis and potential therapeutic advances

Sepsis is a life-threatening condition characterised by endothelial barrier dysfunction and impairment of normal microcirculatory function, resulting in a state of hypoperfusion and tissue oedema. No specific pharmacological therapies are currently used to attenuate microvascular injury. Given the prominent role of endothelial breakdown and microcirculatory dysfunction in sepsis, there is a need for effective strategies to protect the endothelium. In this review we will discuss key mechanisms and putative therapeutic agents relevant to endothelial barrier function.

A proteomic study on gastric impairment in rats caused by microcystin-LR

Microcystins (MCs) are the most common cyanobacterial toxins. Epidemiological investigation showed that exposure to MCs can cause gastro-intestinal symptoms, gastroenteritis and gastric cancer. MCs can also accumulate in and cause histopathological damage to stomach. However, the exact mechanisms by which MCs cause gastric injury were unclear. In this study, Wistar rats were administrated 50, 75 or 100 μg microcystin-LR (MC-LR)/kg, body mass (bm) via tail vein, and histopathology, response of anti-oxidant system and the proteome of gastric tissues at 24 h after exposure were studied. Bleeding of fore-stomach and gastric corpus, inflammation and necrosis in gastric corpus and exfoliation of mucosal epithelial cells in gastric antrum were observed following acute MC-LR exposure. Compared with controls, activities of superoxide dismutase (SOD) were significantly greater in gastric tissues of exposed rats, while activities of catalase (CAT) were less in rats administrated 50 μg MC-LR/kg, bm, and concentrations of glutathione (GSH) and malondialdehyde (MDA) were greater in rats administrated 75 or 100 μg MC-LR/kg, bm. These results indicated that MC-LR could disrupt the anti-oxidant system and cause oxidative stress. The proteomic results revealed that MC-LR could affect expressions of proteins related to cytoskeleton, immune system, gastric functions, and some signaling pathways, including platelet activation, complement and coagulation cascades, and ferroptosis. Quantitative real-time PCR (qRT-PCR) analysis showed that transcriptions of genes for ferroptosis and gastric function were altered, which confirmed results of proteomics. Overall, this study illustrated that MC-LR could induce gastric dysfunction, and ferroptosis might be involved in MC-LR-induced gastric injury. This study provided novel insights into mechanisms of digestive diseases induced by MCs.

Diversity of Intercellular Communication Modes: A Cancer Biology Perspective

From the moment a cell is on the path to malignant transformation, its interaction with other cells from the microenvironment becomes altered. The flow of molecular information is at the heart of the cellular and systemic fate in tumors, and various processes participate in conveying key molecular information from or to certain cancer cells. For instance, the loss of tight junction molecules is part of the signal sent to cancer cells so that they are no longer bound to the primary tumors and are thus free to travel and metastasize. Upon the targeting of a single cell by a therapeutic drug, gap junctions are able to communicate death information to by-standing cells. The discovery of the importance of novel modes of cell-cell communication such as different types of extracellular vesicles or tunneling nanotubes is changing the way scientists look at these processes. However, are they all actively involved in different contexts at the same time or are they recruited to fulfill specific tasks? What does the multiplicity of modes mean for the overall progression of the disease? Here, we extend an open invitation to think about the overall significance of these questions, rather than engage in an elusive attempt at a systematic repertory of the mechanisms at play.

Border Control: The Role of the Microbiome in Regulating Epithelial Barrier Function

The gut mucosal epithelium is one of the largest organs in the body and plays a critical role in regulating the crosstalk between the resident microbiome and the host. To this effect, the tight control of what is permitted through this barrier is of high importance. There should be restricted passage of harmful microorganisms and antigens while at the same time allowing the absorption of nutrients and water. An increased gut permeability, or "leaky gut", has been associated with a variety of diseases ranging from infections, metabolic diseases, and inflammatory and autoimmune diseases to neurological conditions. Several factors can affect gut permeability, including cytokines, dietary components, and the gut microbiome. Here, we discuss how the gut microbiome impacts the permeability of the gut epithelial barrier and how this can be harnessed for therapeutic purposes.

Raludotatug Deruxtecan, a CDH6-Targeting Antibody-Drug Conjugate with a DNA Topoisomerase I Inhibitor DXd, Is Efficacious in Human Ovarian and Kidney Cancer Models

Cadherin-6 (CDH6) is expressed in several cancer types, but no CDH6-targeted therapy is currently clinically available. Here, we generated raludotatug deruxtecan (R-DXd; DS-6000), a novel CDH6-targeting antibody-drug conjugate with a potent DNA topoisomerase I inhibitor, and evaluated its properties, pharmacologic activities, and safety profile. In vitro pharmacologic activities and the mechanisms of action of R-DXd were assessed in serous-type ovarian cancer and renal cell carcinoma cell lines. In vivo pharmacologic activities were evaluated with several human cancer cell lines and patient-derived xenograft mouse models. The safety profile in cynomolgus monkeys was also assessed. R-DXd exhibited CDH6 expression-dependent cell growth-inhibitory activity and induced tumor regression in xenograft models. In this process, R-DXd specifically bound to CDH6, was internalized into cancer cells, and then translocated to the lysosome. The DXd released from R-DXd induced the phosphorylation of Chk1, a DNA damage marker, and cleaved caspase-3, an apoptosis marker, in cancer cells. It was also confirmed that the DXd payload had a bystander effect, passing through the cell membrane and impacting surrounding cells. The safety profile of R-DXd was favorable and the highest non-severely toxic dose was 30 mg/kg in cynomolgus monkeys. R-DXd demonstrated potent antitumor activity against CDH6-expressing tumors in mice and an acceptable safety profile in monkeys. These findings indicate the potential of R-DXd as a new treatment option for patients with CDH6-expressing serous-type ovarian cancer and renal cell carcinoma in a clinical setting.

Cell-cell interaction in the pathogenesis of inherited retinal diseases

The retina is part of the central nervous system specialized for vision. Inherited retinal diseases (IRD) are a group of clinically and genetically heterogenous disorders that lead to progressive vision impairment or blindness. Although each disorder is rare, IRD accumulatively cause blindness in up to 5.5 million individuals worldwide. Currently, the pathophysiological mechanisms of IRD are not fully understood and there are limited treatment options available. Most IRD are caused by degeneration of light-sensitive photoreceptors. Genetic mutations that abrogate the structure and/or function of photoreceptors lead to visual impairment followed by blindness caused by loss of photoreceptors. In healthy retina, photoreceptors structurally and functionally interact with retinal pigment epithelium (RPE) and Müller glia (MG) to maintain retinal homeostasis. Multiple IRD with photoreceptor degeneration as a major phenotype are caused by mutations of RPE- and/or MG-associated genes. Recent studies also reveal compromised MG and RPE caused by mutations in ubiquitously expressed ciliary genes. Therefore, photoreceptor degeneration could be a direct consequence of gene mutations and/or could be secondary to the dysfunction of their interaction partners in the retina. This review summarizes the mechanisms of photoreceptor-RPE/MG interaction in supporting retinal functions and discusses how the disruption of these processes could lead to photoreceptor degeneration, with an aim to provide a unique perspective of IRD pathogenesis and treatment paradigm. We will first describe the biology of retina and IRD and then discuss the interaction between photoreceptors and MG/RPE as well as their implications in disease pathogenesis. Finally, we will summarize the recent advances in IRD therapeutics targeting MG and/or RPE.

Evaluation of the in vitro human skin percutaneous absorption of ketoprofen in topical anhydrous and aqueous gels

BACKGROUND

Ketoprofen is a nonsteroidal anti-inflammatory drug used for the treatment of acute and chronic pain associated with inflammatory conditions. This study aims to evaluate the in vitro percutaneous absorption of ketoprofen 10% formulated in proprietary anhydrous and aqueous gels using the Franz skin finite dose model.

MATERIALS AND METHODS

The anhydrous gel was initially characterized for cytotoxicity using EpiDerm skin tissue model by cell proliferation assay and Western blot analysis. The Ultra Performance Liquid Chromatography method for measuring ketoprofen was validated and the stability of ketoprofen 10% in the anhydrous gel formulation was evaluated at 5°C and 25°C for 181 days. The percutaneous absorption of ketoprofen was determined using donated human skin. The tissue sections were mounted within Franz diffusion cells. A variable finite dose of each ketoprofen formulation in either anhydrous or aqueous gel was applied to the skin sections and receptor solutions were collected at various time points.

RESULTS

Cell proliferation assay showed minimal cell death when EpiDerm skin tissue was exposed to the anhydrous gel for 24 h; the levels of protein markers of cell proliferation were not affected after 17-h exposure. Ketoprofen was stable in the anhydrous gel when stored at 5°C and 25°C. When compounded in the anhydrous and aqueous gels, ketoprofen had mean flux rate of 2.22 and 2.50 μg/cm2 /h, respectively, after 48 h. The drug was distributed to the epidermis and dermis sections of the skin. Both the anhydrous and aqueous gels facilitated the percutaneous absorption of ketoprofen without statistically significant differences.

CONCLUSION

The anhydrous gel can be used as a base to facilitate the transdermal delivery of ketoprofen. Although the anhydrous and aqueous gels can deliver a similar amount of ketoprofen, the anhydrous gel (water activity below 0.6) allows for extended default beyond-use-date of compounding preparations.

MUC13 negatively regulates tight junction proteins and intestinal epithelial barrier integrity via protein kinase C

Glycosylated mucin proteins contribute to the essential barrier function of the intestinal epithelium. The transmembrane mucin MUC13 is an abundant intestinal glycoprotein with important functions for mucosal maintenance that are not yet completely understood. We demonstrate that in human intestinal epithelial monolayers, MUC13 localized to both the apical surface and the tight junction (TJ) region on the lateral membrane. MUC13 deletion resulted in increased transepithelial resistance (TEER) and reduced translocation of small solutes. TEER buildup in ΔMUC13 cells could be prevented by addition of MLCK, ROCK or protein kinase C (PKC) inhibitors. The levels of TJ proteins including claudins and occludin were highly increased in membrane fractions of MUC13 knockout cells. Removal of the MUC13 cytoplasmic tail (CT) also altered TJ composition but did not affect TEER. The increased buildup of TJ complexes in ΔMUC13 and MUC13-ΔCT cells was dependent on PKC. The responsible PKC member might be PKCδ (or PRKCD) based on elevated protein levels in the absence of full-length MUC13. Our results demonstrate for the first time that a mucin protein can negatively regulate TJ function and stimulate intestinal barrier permeability.

The cytotoxicity of microcystin-LR: ultrastructural and functional damage of cells

Microcystin-LR (MC-LR) is a toxin produced by cyanobacteria, which is widely distributed in eutrophic water bodies and has multi-organ toxicity. Previous cytotoxicity studies have mostly elucidated the effects of MC-LR on intracellular-related factors, proteins, and DNA at the molecular level. However, there have been few studies on the adverse effects of MC-LR on cell ultrastructure and function. Therefore, research on the cytotoxicity of MC-LR in recent years was collected and summarized. It was found that MC-LR can induce a series of cytotoxic effects, including decreased cell viability, induced autophagy, apoptosis and necrosis, altered cell cycle, altered cell morphology, abnormal cell migration and invasion as well as leading to genetic damage. The above cytotoxic effects were related to the damage of various ultrastructure and functions such as cell membranes and mitochondria. Furthermore, MC-LR can disrupt cell ultrastructure and function by inducing oxidative stress and inhibiting protein phosphatase activity. In addition, the combined toxic effects of MC-LR and other environmental pollutants were investigated. This review explored the toxic targets of MC-LR at the subcellular level, which will provide new ideas for the prevention and treatment of multi-organ toxicity caused by MC-LR.

The population context is a driver of the heterogeneous response of epithelial cells to interferons

Isogenic cells respond in a heterogeneous manner to interferon. Using a micropatterning approach combined with high-content imaging and spatial analyses, we characterized how the population context (position of a cell with respect to neighboring cells) of epithelial cells affects their response to interferons. We identified that cells at the edge of cellular colonies are more responsive than cells embedded within colonies. We determined that this spatial heterogeneity in interferon response resulted from the polarized basolateral interferon receptor distribution, making cells located in the center of cellular colonies less responsive to ectopic interferon stimulation. This was conserved across cell lines and primary cells originating from epithelial tissues. Importantly, cells embedded within cellular colonies were not protected from viral infection by apical interferon treatment, demonstrating that the population context-driven heterogeneous response to interferon influences the outcome of viral infection. Our data highlights that the behavior of isolated cells does not directly translate to their behavior in a population, placing the population context as one important factor influencing heterogeneity during interferon response in epithelial cells.

A Protective Role of Canonical Wnt/β-Catenin Pathway in Pathogenic Bacteria-Induced Inflammatory Responses

Inflammation is a complex host defensive response against various disease-associated pathogens. A baseline extent of inflammation is supposed to be tightly associated with a sequence of immune-modulated processes, resulting in the protection of the host organism against pathogen invasion; however, as a matter of fact is that an uncontrolled inflammatory cascade is the main factor responsible for the host damage, accordingly suggesting a significant and indispensable involvement of negative feedback mechanism in modulation of inflammation. Evidence accumulated so far has supported a repressive effect of the canonical Wnt/β-catenin pathway on microbial-triggered inflammation via diverse mechanisms, although that consequence is dependent on the cellular context, types of stimuli, and cytokine environment. It is of particular interest and importance to comprehend the precise way in which the Wnt/β-catenin pathway is activated, due to its essential anti-inflammatory properties. It is assumed that an inflammatory milieu is necessary for initiating and activating this signaling, implying that Wnt activity is responsible for shielding tissues from overwhelming inflammation, thus sustaining a balanced physiological condition against bacterial infection. This review gathers the recent efforts to elucidate the mechanistic details through how Wnt/β-catenin signaling modulates anti-inflammatory responses in response to bacterial infection and its interactions with other inflammatory signals, which warrants further study for the development of specific interventions for the treatment of inflammatory diseases. Further clinical trials from different disease settings are required.

Helical vasculogenesis driven by cell chirality

The cellular helical structure is well known for its crucial role in development and disease. Nevertheless, the underlying mechanism governing this phenomenon remains largely unexplored, particularly in recapitulating it in well-controlled engineering systems. Leveraging advanced microfluidics, we present compelling evidence of the spontaneous emergence of helical endothelial tubes exhibiting robust right-handedness governed by inherent cell chirality. To strengthen our findings, we identify a consistent bias toward the same chirality in mouse vascular tissues. Manipulating endothelial cell chirality using small-molecule drugs produces a dose-dependent reversal of the handedness in engineered vessels, accompanied by non-monotonic changes in vascular permeability. Moreover, our three-dimensional cell vertex model provides biomechanical insights into the chiral morphogenesis process, highlighting the role of cellular torque and tissue fluidity in its regulation. Our study unravels an intriguing mechanism underlying vascular chiral morphogenesis, shedding light on the broader implications and distinctive perspectives of tubulogenesis within biological systems.

Regulation of Epithelial and Endothelial Barriers by Molecular Chaperones

The integrity and permeability of epithelial and endothelial barriers depend on the formation of tight junctions, adherens junctions, and a junction-associated cytoskeleton. The establishment of this junction-cytoskeletal module relies on the correct folding and oligomerization of its protein components. Molecular chaperones are known regulators of protein folding and complex formation in different cellular compartments. Mammalian cells possess an elaborate chaperone network consisting of several hundred chaperones and co-chaperones. Only a small part of this network has been linked, however, to the regulation of intercellular adhesions, and the systematic analysis of chaperone functions at epithelial and endothelial barriers is lacking. This review describes the functions and mechanisms of the chaperone-assisted regulation of intercellular junctions. The major focus of this review is on heat shock protein chaperones, their co-chaperones, and chaperonins since these molecules are the focus of the majority of the articles published on the chaperone-mediated control of tissue barriers. This review discusses the roles of chaperones in the regulation of the steady-state integrity of epithelial and vascular barriers as well as the disruption of these barriers by pathogenic factors and extracellular stressors. Since cytoskeletal coupling is essential for junctional integrity and remodeling, chaperone-assisted assembly of the actomyosin cytoskeleton is also discussed.

Epithelial-Mesenchymal Transition in Acute Leukemias

Epithelial-mesenchymal transition (EMT) is a metabolic process that confers phenotypic flexibility to cells and the ability to adapt to new functions. This transition is critical during embryogenesis and is required for the differentiation of many tissues and organs. EMT can also be induced in advanced-stage cancers, leading to further malignant behavior and chemotherapy resistance, resulting in an unfavorable prognosis for patients. Although EMT was long considered and studied only in solid tumors, it has been shown to be involved in the pathogenesis of hematological malignancies, including acute leukemias. Indeed, there is increasing evidence that EMT promotes the progression of acute leukemias, leading to the emergence of a more aggressive phenotype of the disease, and also causes chemotherapy resistance. The current literature suggests that the levels and activities of EMT inducers and markers can be used to predict prognosis, and that targeting EMT in addition to conventional therapies may increase treatment success in acute leukemias.

Therapeutic Potential of Natural Compounds from Herbs and Nutraceuticals in Alleviating Neurological Disorders: Targeting the Wnt Signaling Pathway

As an important signaling pathway in multicellular eukaryotes, the Wnt signaling pathway participates in a variety of physiological processes. Recent studies have confirmed that the Wnt signaling pathway plays an important role in neurological disorders such as stroke, Alzheimer's disease, and Parkinson's disease. The regulation of Wnt signaling by natural compounds in herbal medicines and nutraceuticals has emerged as a potential strategy for the development of new drugs for neurological disorders. Purpose: The aim of this review is to evaluate the latest research results on the efficacy of natural compounds derived from herbs and nutraceuticals in the prevention and treatment of neurological disorders by regulating the Wnt pathway in vivo and in vitro. A manual and electronic search was performed for English articles available from PubMed, Web of Science, and ScienceDirect from the January 2010 to February 2023. Keywords used for the search engines were "natural products,″ "plant derived products,″ "Wnt+ clinical trials,″ and "Wnt+,″ and/or paired with "natural products″/″plant derived products", and "neurological disorders." A total of 22 articles were enrolled in this review, and a variety of natural compounds from herbal medicine and nutritional foods have been shown to exert therapeutic effects on neurological disorders through the Wnt pathway, including curcumin, resveratrol, and querctrin, etc. These natural products possess antioxidant, anti-inflammatory, and angiogenic properties, confer neurovascular unit and blood-brain barrier integrity protection, and affect neural stem cell differentiation, synaptic formation, and neurogenesis, to play a therapeutic role in neurological disorders. In various in vivo and in vitro studies and clinical trials, these natural compounds have been shown to be safe and tolerable with few adverse effects. Natural compounds may serve a therapeutic role in neurological disorders by regulating the Wnt pathway. This summary of the research progress of natural compounds targeting the Wnt pathway may provide new insights for the treatment of neurological disorders and potential targets for the development of new drugs.

A Conformable Organic Electronic Device for Monitoring Epithelial Integrity at the Air Liquid Interface

Air liquid interfaced (ALI) epithelial barriers are essential for homeostatic functions such as nutrient transport and immunological protection. Dysfunction of such barriers are implicated in a variety of autoimmune and inflammatory disorders and, as such, sensors capable of monitoring barrier health are integral for disease modelling, diagnostics and drug screening applications. To date, gold-standard electrical methods for detecting barrier resistance require rigid electrodes bathed in an electrolyte, which limits compatibility with biological architectures and is non-physiological for ALI. This work presents a flexible all-planar electronic device capable of monitoring barrier formation and perturbations in human respiratory and intestinal cells at ALI. By interrogating patient samples with electrochemical impedance spectroscopy and simple equivalent circuit models, disease-specific and patient-specific signatures are uncovered. Device readouts are validated against commercially available chopstick electrodes and show greater conformability, sensitivity and biocompatibility. The effect of electrode size on sensing efficiency is investigated and a cut-off sensing area is established, which is one order of magnitude smaller than previously reported. This work provides the first steps in creating a physiologically relevant sensor capable of mapping local and real-time changes of epithelial barrier function at ALI, which will have broad applications in toxicology and drug screening applications.

Overview of the compromised mucosal integrity in celiac disease

Intestinal epithelium is a dynamic cellular layer that lines the small-bowel and makes a relatively impenetrable barrier to macromolecules. Intestinal epithelial cell polarity is crucial in coordinating signalling pathways within cells and mainly regulated by three conserved polarity protein complexes, the Crumbs (Crb) complex, partitioning defective (PAR) complex, and Scribble (Scrib) complex. Polarity proteins regulate the proper establishment of the intercellular junctional complexes including tight junctions (TJs), adherence junctions (AJs), and desmosomes which hold epithelial cells together and play a major role in maintaining intestinal barrier integrity. Impaired intestinal epithelial cell polarity and barrier integrity result in irreversible immune responses, the host- microbial imbalance and intestinal inflammatory disorders. Disassembling the epithelial tight junction and augmented paracellular permeability is a conspicuous hallmark of celiac disease (CD) pathogenesis. There are several dietary components that can improve intestinal integrity and function. The aim of this review article is to summarize current information about the association of polarity proteins and AJC damages with pathogenesis of CD.

Pharmacological effects of biologically synthesized ginsenoside CK-rich preparation (AceCK40) on the colitis symptoms in DSS-induced Caco-2 cells and C57BL mice

BACKGROUND

Despite the notable pharmacological potential of natural ginsenosides, their industrial application is hindered by low oral bioavailability. Recent research centers on the production of less-glycosylated minor ginsenosides.

PURPOSE

This study aimed to explore the effect of a biologically synthesized ginsenoside CK-rich minor ginsenoside complex (AceCK40), on ameliorating colitis using DSS-induced colitis models in vitro and in vivo.

METHODS

The ginsenoside composition of AceCK40 was determined by HPLC-ELSD and UHPLC-MS/MS analyses. In vitro colitis model was established using dextran sodium sulfate (DSS)-induced Caco-2 intestinal epithelial model. For in vivo experiments, DSS-induced severe colitis mouse model was established.

RESULTS

In DSS-stimulated Caco-2 cells, AceCK40 downregulated mitogen-activated protein kinase (MAPK) activation (p < 0.05), inhibited monocyte chemoattractant protein-1 (MCP-1) production (p < 0.05), and enhanced MUC2 expression (p < 0.05), mediated via signaling pathway regulation. Daily AceCK40 administration at doses of 10 and 30 mg/kg/day was well tolerated by DSS-induced severe colitis mice. These doses led to significant alleviation of disease activity index score (> 36.0% decrease, p < 0.05), increased luminal immunoglobulin (Ig)G (> 37.6% increase, p < 0.001) and IgA (> 33.8% increase, p < 0.001), lowered interleukin (IL)-6 (> 65.7% decrease, p < 0.01) and MCP-1 (> 116.2% decrease, p < 0.05), as well as elevated serum IgA (> 51.4% increase, p < 0.001) and lowered serum IL-6 (112.3% decrease at 30 mg/kg, p < 0.001). Hematoxylin and eosin (H&E) and periodic acid-Schiff (PAS) staining revealed that DSS-mediated thickening of the muscular externa, extensive submucosal edema, crypt distortion, and decreased mucin droplets were significantly alleviated by AceCK40 administration. Additionally, daily administration of AceCK40 led to significant recovery of colonic tight junctions damaged by DSS through the elevation in the expression of adhesion molecules, including occludin, E-cadherin, and N-cadherin.

CONCLUSION

This study presents the initial evidence elucidating the anti-colitis effects of AceCK40 and its underlying mechanism of action through sequential in vitro and in vivo systems employing DSS stimulation. Our findings provide valuable fundamental data for the utilization of AceCK40 in the development of novel anti-colitis candidates.

A duodenal mucosa transcriptome study identified reduced expression of a novel gene CDH18 in celiac disease

BACKGROUND

Celiac disease (CD) a complex immune disease that affects duodenal mucosa. Identification of tissue specific biomarkers is expected to improve the existing biopsy based CD diagnosis.

AIMS

To investigate the differentially expressed genes (DEGs) in duodenal mucosa tissue to identify clinically relevant gene expression pattern in CD.

METHODS

Whole RNA extracted from the duodenal biopsies of three CD patients and four non-CD controls were sequenced. Significant DEGs were identified. Prioritized DEGs were validated using qRT-PCR in an independent group (CD=23; Control=26). Enriched pathways were analyzed, protein-protein interaction networks were evaluated.

RESULTS

923 DEGs comprising of 135 up-regulated, and 788 down-regulated genes, with p-value≤0.05; log2FC>2 or <-2 were identified. A novel down-regulated gene CDH18 (p = 0.03; log2FC=-0.74) was identified. Previously known CXCL9 was replicated. CDH18, a trans-membrane protein was found to interact with other CDH proteins, α/β catenins, and other membrane transporters such as SLC and ABCB. Pathways and protein networks contributing in channel activity (p = 2.15E-12), membrane transporters (p = 2.15E-12), and cellular adhesion (p = 8.05E-6) were identified.

CONCLUSIONS

CDH18, a novel DEG identified in the present study is a pivotal gene involved in maintaining epithelial membrane organization and integrity. The functional significance of lower expression of CDH18 in pathogenesis of CD warranted to be investigated. CDH18 expression could be tested for its effectiveness in diagnostic, prognostic and therapeutic purposes.

Cellular junction dynamics and Alzheimer's disease: a comprehensive review

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder characterized by progressive neuronal damage and cognitive decline. Recent studies have shed light on the involvement of not only the blood-brain barrier (BBB) dysfunction but also significant alterations in cellular junctions in AD pathogenesis. In this review article, we explore the role of the BBB and cellular junctions in AD pathology, with a specific focus on the hippocampus. The BBB acts as a crucial protective barrier between the bloodstream and the brain, maintaining brain homeostasis and regulating molecular transport. Preservation of BBB integrity relies on various junctions, including gap junctions formed by connexins, tight junctions composed of proteins such as claudins, occludin, and ZO-1, as well as adherence junctions involving molecules like vascular endothelial (VE) cadherin, Nectins, and Nectin-like molecules (Necls). Abnormalities in these junctions and junctional components contribute to impaired neuronal signaling and increased cerebrovascular permeability, which are closely associated with AD advancement. By elucidating the underlying molecular mechanisms governing BBB and cellular junction dysfunctions within the context of AD, this review offers valuable insights into the pathogenesis of AD and identifies potential therapeutic targets for intervention.

Horizontal and vertical microchamber platforms for evaluation of the paracellular permeability of an epithelial cell monolayer

Epithelial cells serve as a barrier by tightly adhering to each other and contribute to the homeostasis of living organisms by controlling substance permeation. Therefore, evaluation of the barrier function is important in pharmaceutical development processes. However, the widely used Transwell-based assays require the development of the defect-free epithelial cell monolayer above several tens of mm2, often resulting in low reproducibility and requiring a long incubation time. In addition, the culture surface of cells is far from the bottom of the well plate, making it difficult to observe the cell morphology using an optical microscope. Herein, we propose simple polydimethylsiloxane microfluidic devices for evaluating the barrier function of an epithelial monolayer using a microchamber array. After the formation of the epithelial monolayer over microchambers, the permeation of the marker molecules introduced above resulted in increased fluorescence intensity in microchambers, which was monitored using confocal laser scanning microscopy. We show that using this technique, alteration of the paracellular permeability induced by sodium caprate (C10) and cytochalasin-D, permeation enhancing factors, can be elucidated. Furthermore, by tilting the microchamber device 90 degrees, the vertical cell section and microchambers were imaged in the same focal plane, allowing for live visualization of the passage of fluorescent substances across the cell monolayer. This technique is expected to be useful for investigating the relationship between paracellular permeability and cell morphology, which is unattainable through conventional methods.

Campylobacter jejuni Surface-Bound Protease HtrA, but Not the Secreted Protease nor Protease in Shed Membrane Vesicles, Disrupts Epithelial Cell-to-Cell Junctions

Fundamental functions of the intestinal epithelium include the digestion of food, absorption of nutrients, and its ability to act as the first barrier against intruding microbes. Campylobacter jejuni is a major zoonotic pathogen accounting for a substantial portion of bacterial foodborne illnesses. The germ colonizes the intestines of birds and is mainly transmitted to humans through the consumption of contaminated poultry meat. In the human gastrointestinal tract, the bacterium triggers campylobacteriosis that can progress to serious secondary disorders, including reactive arthritis, inflammatory bowel disease and Guillain-Barré syndrome. We recently discovered that C. jejuni serine protease HtrA disrupts intestinal epithelial barrier functions via cleavage of the tight and adherens junction components occludin, claudin-8 and E-cadherin. However, it is unknown whether epithelial damage is mediated by the secreted soluble enzyme, by HtrA contained in shed outer-membrane vesicles (OMVs) or by another mechanism that has yet to be identified. In the present study, we investigated whether soluble recombinant HtrA and/or purified OMVs induce junctional damage to polarized intestinal epithelial cells compared to live C. jejuni bacteria. By using electron and confocal immunofluorescence microscopy, we show that HtrA-expressing C. jejuni bacteria trigger efficient junctional cell damage, but not soluble purified HtrA or HtrA-containing OMVs, not even at high concentrations far exceeding physiological levels. Instead, we found that only bacteria with active protein biosynthesis effectively cleave junctional proteins, which is followed by paracellular transmigration of C. jejuni through the epithelial cell layer. These findings shed new light on the pathogenic activities of HtrA and virulence strategies of C. jejuni.