Identification Of Barrier Research Articles

Enzyme Tunnel Dynamics and Catalytic Mechanism of Norcoclaurine Synthase: Insights from a Combined LiGaMD and DFT Study.

This study conducts a systematic investigation into the catalytic mechanism of norcoclaurine synthase (NCS), a key enzyme in the biosynthesis of tetrahydroisoquinolines (THIQs) with therapeutic applications. By integration of LiGaMD and DFT calculations, the reaction pathway of NCS is mapped, providing detailed insights into its catalytic activity and selectivity. Our findings underscore the critical role of E103 in substrate capture and reveal the hitherto unappreciated influence of nonpolar residues M183 and L76 on tunnel dynamics. A prominent discovery is the identification of a high-energy barrier (44.2 kcal/mol) associated with the aromatic electrophilic attack, which pinpoints the rate-limiting step. Moreover, we disclose the existence of dual transition states leading to different products with the energetically favored six-membered ring formation consistent with experimental evidence. These mechanistic revelations not only refine our understanding of NCS but also advocate for a renewed emphasis on enzyme tunnel engineering for optimizing THIQs biosynthesis. The research sets the stage for translating these findings into practical enzyme modifications. Our results highlight the potential of NCS as a biocatalyst to overcome the limitations of current synthetic methodologies, such as low yields and environmental impacts, and provide a theoretical contribution to the efficient, eco-friendly production of THIQs-based pharmaceuticals.

Identification of extracellular polymeric substances layer barrier in chloroquine phosphate-disturbed anammox consortia and mechanism dissection on cytotoxic behavior by computational chemistry

The over-dosing use of chloroquine phosphate (CQ) poses severe threats to human beings and ecosystem due to the high persistence and biotoxicity. The discharge of CQ into wastewater would affect the biomass activity and process stability during the biological processes, e.g., anammox. However, the response mechanism of anammox consortia to CQ remain unknown. In this study, the accurate role of extracellular polymeric substances barrier in attenuating the negative effects of CQ, and the mechanism on cytotoxic behavior were dissected by molecular spectroscopy and computational chemistry. Low concentrations (≤6.0 mg/L) of CQ hardly affected the nitrogen removal performance due to the adaptive evolution of EPS barrier and anammox bacteria. Compact protein of EPS barrier can bind more CQ (0.24 mg) by hydrogen bond and van der Waals force, among which O-H and amide II region respond CQ binding preferentially. Importantly, EPS contributes to the microbiota reshape with selectively enriching Candidatus_Kuenenia for self-protection. Furthermore, the macroscopical cytotoxic behavior was dissected at a molecular level by CQ fate/distribution and computational chemistry, suggesting that the toxicity was ascribed to attack of CQ on functional proteins of anammox bacteria with atom N17 (f–=0.1209) and C2 (f+=0.1034) as the most active electrophilic and nucleophilic sites. This work would shed the light on the fate and risk of non-antibiotics in anammox process.

Training as a facilitator for Industry 4.0

Purpose This paper studies the impact of certain characteristics of companies to training programs in the Industry 4.0 (I4.0) context. Partial objective is to rank the main human barriers companies have to overcome so that they can digitalize.Design/methodology/approach To accomplish the objectives, a closed-ended questionnaire was sent to Slovak and Italian companies and analyzed using statistical nonparametric tests. The partial objective was achieved using the so-called Henry-Garrett’s ranking method.Findings Results show the significance impact of companies’ characteristics such as foreign participation and company dimension on training practices whereas economic situation (financial health) seems not to influence it.Research limitations/implications The study may lack generalizability as only 102 answers were collected. Perhaps, the outcome would be different with another sample from other countries. Moreover, using closed-ended questions, certain features may not have been covered.Practical implications Companies should always guarantee training for the resulted benefits. It is fundamental for organizations to find a time gap, resources and professionals who can teach these programs. Even when companies are incurring financial problems they should do so since human capital development can increase their competitiveness. The most critical barriers should be carefully addressed by companies. Training can help to overcome I4.0 barriers related to Human Resources (HR) and contribute to its growth.Originality/value This paper gives insights of the impact of certain characteristics of companies to the training programs. Because past research has limited their analysis on the identification of barrier, its novelty lies in the attempt to rank the most significant barriers among those detected by other authors in previous research.

Identification of a tumour immune barrier in the HCC microenvironment that determines the efficacy of immunotherapy

The tumour microenvironment (TME) is a crucial mediator of cancer progression and therapeutic outcome. The TME subtype correlates with patient response to immunotherapy in multiple cancers. Most previous studies have focused on the role of different cellular components in the TME associated with immunotherapy efficacy. However, the specific structure of the TME and its role in immunotherapy efficacy remain largely unknown. We combined spatial transcriptomics with single-cell RNA-sequencing and multiplexed immunofluorescence to identify the specific spatial structures in the TME that determine the efficacy of immunotherapy in patients with hepatocellular carcinoma (HCC) receiving anti-PD-1 treatment. We identified a tumour immune barrier (TIB) structure, a spatial niche composed of SPP1+ macrophages and cancer-associated fibroblasts (CAFs) located near the tumour boundary, which is associated with the efficacy of immune checkpoint blockade. Furthermore, we dissected ligand‒receptor networks among malignant cells, SPP1+ macrophages, and CAFs; that is, the hypoxic microenvironment promotes SPP1 expression, and SPP1+ macrophages interact with CAFs to stimulate extracellular matrix remodelling and promote TIB structure formation, thereby limiting immune infiltration in the tumour core. Preclinically, the blockade of SPP1 or macrophage-specific deletion of Spp1 in mice led to enhanced efficacy of anti-PD-1 treatment in mouse liver cancer, accompanied by reduced CAF infiltration and increased cytotoxic T-cell infiltration. We identified that the TIB structure formed by the interaction of SPP1+ macrophages and CAFs is related to immunotherapy efficacy. Therefore, disruption of the TIB structure by blocking SPP1 may be considered a relevant therapeutic approach to enhance the therapeutic effect of immune checkpoint blockade in HCC. Only a limited number of patients with hepatocellular carcinoma (HCC) benefit from tumour immunotherapy, which significantly hinders its application. Herein, we used multiomics to identify the spatial structure of the tumour immune barrier (TIB), which is formed by the interaction of SPP1+ macrophages and cancer-associated fibroblasts in the HCC microenvironment. This structure constrains immunotherapy efficacy by limiting immune cell infiltration into malignant regions. Preclinically, we revealed that blocking SPP1 or macrophage-specific deletion of Spp1 in mice could destroy the TIB structure and sensitize HCC cells to immunotherapy. These results provide the first key steps towards finding more effective therapies for HCC and have implications for physicians, scientists, and drug developers in the field of HCC.

Mucosal plasma cells are required to protect the upper airway and brain from infection.

While blood antibodies mediate protective immunity in most organs, whether they protect nasal surfaces in the upper airway is unclear. Using multiple viral infection models in mice, we found that blood-borne antibodies could not defend the olfactory epithelium. Despite high serum antibody titers, pathogens infected nasal turbinates, and neurotropic microbes invaded the brain. Using passive antibody transfers and parabiosis, we identified a restrictive blood-endothelial barrier that excluded circulating antibodies from the olfactory mucosa. Plasma cell depletions demonstrated that plasma cells must reside within olfactory tissue to achieve sterilizing immunity. Antibody blockade and genetically deficient models revealed that this local immunity required CD4+ Tcells and CXCR3. Many vaccine adjuvants failed to generate olfactory plasma cells, but mucosal immunizations established humoral protection of the olfactory surface. Our identification of a blood-olfactory barrier and the requirement for tissue-derived antibody has implications for vaccinology, respiratory and CNS pathogen transmission, and B cell fate decisions.

Characterization of Aripiprazole Uptake Transporter in the Blood-Brain Barrier Model hCMEC/D3 Cells by Targeted siRNA Screening.

Identification of blood-brain barrier (BBB) uptake transporters is a major challenge in the research and development of central nervous system (CNS) drugs. However, conventional methods that consider known drug uptake characteristics have failed at identifying the responsible transporter molecule. The present study aimed at identifying aripiprazole uptake transporters in BBB model hCMEC/D3 cells using a knockdown screening study targeting various transporters, including uncharacterized ones. We evaluated the effect of 214 types of siRNA targeting transporters on the uptake of aripiprazole, an atypical antipsychotic drug, in hCMEC/D3 cells. Aripiprazole uptake was determined using Xenopus oocytes expressing the candidate genes extracted from the siRNA screening assay. The estimated unbound brain to plasma concentration ratio (Kp,uu,brain) of aripiprazole was estimated as 0.67 in wild-type mice and 1.94 in abcb1a/1b/abcg2 knockout mice, suggesting the involvement of both uptake and efflux transporters in BBB permeation. According to siRNA knockdown screening studies, organic cation/carnitine transporter 2 (OCTN2) and long-chain fatty acid transporter 1 (FATP1) were identified as candidate genes. The uptake of aripiprazole by hCMEC/D3 cells was decreased by OCTN2 inhibitors, but not by FATP1 inhibitors. A partially increased uptake of aripiprazole was observed in OCTN2-expressing Xenopus oocytes. Finally, to evaluate transporter-mediated BBB permeation of drugs, the reported and estimated Kp,uu,brain values were summarized. A knockdown screening study in combination with Kp,uu,brain values showed that aripiprazole was a potential substrate of OCTN2. The technique described in this study can be applied to identifying novel BBB transporters for CNS drugs.

Identification of a choroid plexus vascular barrier closing during intestinal inflammation.

Up to 40% of patients with inflammatory bowel disease present with psychosocial disturbances. We previously identified a gut vascular barrier that controls the dissemination of bacteria from the intestine to the liver. Here, we describe a vascular barrier in the brain choroid plexus (PVB) that is modulated in response to intestinal inflammation through bacteria-derived lipopolysaccharide. The inflammatory response induces PVB closure after gut vascular barrier opening by the up-regulation of the wingless-type, catenin-beta 1 (Wnt/β-catenin) signaling pathway, rendering it inaccessible to large molecules. In a model of genetically driven closure of choroid plexus endothelial cells, we observed a deficit in short-term memory and anxiety-like behavior, suggesting that PVB closure may correlate with mental deficits. Inflammatory bowel disease–related mental symptoms may thus be the consequence of a deregulated gut–brain vascular axis.

Creep behavior identification of an environmental barrier coating using full-field measurements

For the use of thermal and environmental barrier coating (T/EBC) with ceramic matrix composites, it is crucial to master the behavior under (extreme) environments representative of the hot section of engine turbines. An experimental setup to simulate such thermal loading has been developed with various diagnostics enabling for kinematic and thermal field measurements, which are used to drive a finite element model and estimate thermomechanical properties such as creep parameters of the coating.

Enablers and barriers of exclusive breastfeeding among employed women in low and lower middle-income countries

ObjectiveThis systematic review and narrative synthesis aims to explore the specific facilitators and barriers of exclusive breastfeeding (EBF) among employed mothers in low and lower middle-income countries. MethodsPrimary quantitative and qualitative studies undertaken in low and lower middle-income countries published from 2003 to 2019 were included in the review. Two reviewers independently assessed each article for eligibility using standardized critical appraisal instruments from the Joanna Briggs Institute. ResultsSeven papers were included in this review. The enabler and barrier factors to EBF are summarized into three categories including maternal factors (such as mode of delivery, number of children, knowledge and attitude on breastfeeding), social factors (such as support from husband, family and child day care), and work-related factors (such as duration of maternal leave, flexibility of work, and availability of physical facilities). ConclusionTo increase EBF among employed women, employers should support them by offering flexible working hours, a minimum of six months maternity leave and providing breastfeeding facilities. Support from family and maternal factors were important factors that could positively affect EBF. Identification of modifiable barrier and facilitator factors may contribute to successful EBF in employed women thereby reducing mortality and morbidity in countries with limited resources.

Impedance spectroscopy of Al/AlN/n-Si metal-insulator-semiconductor (MIS) structures

In this work, a comprehensive characterization of metal-insulator-semiconductor structures by impedance spectroscopy is demonstrated for the case of electrically insulating, highly c-axis oriented, 600 nm sputter-deposited AlN films on n-Si substrates with Al top electrodes. Direct visual analysis and equivalent circuit fitting of the dielectric data were performed. For the latter procedure, the circuit model consisted of three series resistor-capacitor connection elements for the three dielectric contributions detected. The three contributions were identified as the AlN film, n-Si substrate, and an interface barrier effect. Several essential device parameters were determined separately, by visual or equivalent circuit fitting analysis, such as the dielectric permittivity of the AlN layer, the temperature dependence of the AlN permittivity, and the resistances of the AlN layer, the n-Si substrate, and the interface contribution. Furthermore, DC bias dependent impedance measurements allowed the identification of a Schottky-type interface barrier.

Efficiency problems of Child Protection in Lithuania

This article identifies the main problems which have negative impact on efficiency of child protection. The article is based on case analysis of 203 families at social risk carried out in 2015–2016 and on qualitative interviews of 23 children growing in families at social risk which were conducted in 2016–2017. The content and context analysis are performed of the basis of this data. The protection procedures starting with reports to the Department of Child Rights’ Protection, case investigations, application of relevant interventions and finally evaluation of help efficiency are reconstructed. The principles of effective child protection distinguished by Eileen Munro has been chosen as the basis of the evaluation and identification of the main barrier to the efficient child protection. It has been identified that the process of practical protection is not centred on the child’s problems and needs, but it only focuses on the parents’ problems. Children are not sufficiently enabled to participate in their own protection process. Majority of the neglected and abused children are not helped because they are not listened to and their experiences are ignored, although 5 institutional professionals are “working” with the family. The fragments of social work with child has been found only among the experiences of the children attending Children’s Care Day Centres. It can be certainly stated that there is clear lack of services for children. Therefore, it is necessary to strengthen the Children’s Day Care Centres, to find possibilities to finance social workers and psychologists to work with children, since only family (adults) centred protection is not effective. It is recommended to improve the training of child care specialists and raise the professional level of those in practice.

Identification of Barrier for Development of the Sri Lankan Small- and Medium-scale Gem Mining Enterprises: A Case Study Based on Ratnapura District

Small- and medium-scale enterprises (SMEs) have been recognized as a critical segment and lifeline to push development and social improvement in Sri Lanka. Several studies have pointed out that people involved in some informal sector SME activities are opposing to develop that sector due to many reasons. Further, it will be same for the gem mining sector too. Along these lines, this examination may be directed towards recognizing those essential trademarks of gem mining SMEs. This study discusses the primary issues which thwart those improvements in this industry and will suggest necessary arrangements. Methodology should also overcome these imperatives. This study is composed of an investigation in Ratnapura locale with organized questionnaire surveys and meetings with magic stakeholders. Furthermore, this creates far-reaching expositive expression audit. The vicious cycle of the SME model may be utilized to study the prevailing barriers in this industry. Discoveries of the exploration demonstrate that this business is male-dominated. Different ages are also included. Marketing, technology, data and administration and administrative issues are identified as main barriers and basic problems in gem mining industry. Furthermore, gems prices are kept at falsely low level toward those purchasers who come for repeat buys. This is the major barrier in the development of lifestyle of the gem mining people who spend a miserable life, while cunning gem buyers are living a luxurious life on the shoulders of poor. This research endeavour will be directed towards a situational examination.

Can genomic data alone tell us whether speciation happened with gene flow?

The allopatric model, which requires a period of geographical isolation for speciation to complete, has been the standard model in the modern era. Recently, "speciation with gene flow" has been widely discussed in relation to the model of "strict allopatry" and the level of DNA divergence across genomic regions. We wish to caution that genomic data by themselves may only permit the rejection of the simplest form of allopatry. Even a slightly more complex and realistic model that starts with subdivided populations would be impossible to reject by the genomic data alone. To resolve this central issue of speciation, other forms of observations such as the sequencing of reproductive isolation genes or the identification of geographical barrier(s) will be necessary.

Bridge Over Troubled Water: Corporate Law Reform for Life-Cycle Based Governance and Reporting

In spite of all the business initiatives using a sustainability language status quo remains very much unchanged: ‘business as usual’ continues, and is a very certain path towards a very uncertain future. The dire status as regards the convergence of environmental crises facing global society is encapsulated in the concept of ‘planetary boundaries’, first identified in the ground-breaking article by Rockstrom et al. in 2009, and updated and re-affirmed by Steffen et al. in 2015. Planetary boundaries define global sustainability criteria for critical environmental processes that regulate the stability of the life-support systems on Earth, defining nine parameters of the earth system to indicate a safe operating space for humanity. According to Steffen et al., human production and consumption is placing us in increasing or high risk in relation to at least four of the boundaries: climate change, biosphere integrity (genetic diversity, with uncertainty concerning the boundary for functional diversity), land system change, and biogeochemical cycles (phosphorus and nitrogen). The grand challenge of sustainability lies in securing the social foundation for humanity now and in the future, while staying within the planetary boundaries; in Kate Raworth’s words: achieving a safe and just operating space for humanity. Business contribution to meeting this grand challenge is vital. This paper concentrates on the contribution of the dominant legal form of business: the company. The paper first discusses why we are in this situation of corporate unsustainability: why has neither the mainstream corporate governance debate nor the more progressive CSR movement provided helpful answers? The answer lies in the perception of the nature of the company and of the role of regulation that informs these two alternative streams (Section 2), where the social norm of shareholder primacy dominates and where law, and notably company law, to a great extent has been ignored. This is also true of the business and human rights movement, although its innovative approach has the potential for contributing to breaking down barriers between social norms and law.The paper continues with discussing the role of the law, arguably the most powerful tool for society to implement the social norms that society on a high political level agree on: where and how has law failed in ensuring that companies create value in an environmentally, socially and economically sustainable way? That section concludes with an identification of the main barrier to sustainable business: the social norm of shareholder primacy that has taken over the discretionary space company law has given corporate decision makers, and the explanatory power of this recognition for the failure of the most favoured legislative tool for sustainability: reporting (Section 3). Legislative efforts at promoting sustainable business through reporting requirements risk continued failure because of the chasm between the perceived role and duty of the board and by extension management, and what boards and management are asked to report on.The recognition of the chasm between the perceived role and duty of the board and management, and the reporting requirements, helps identify a possible solution (Section 4). The research-based corporate law reform proposal presented here has the potential of being a ‘bridge over troubled water’, spanning this chasm and giving content to the new ‘non-financial’ reporting requirements of the EU. Section 5 concludes.

Prevention of venous thromboembolism amongst patients in an acute tertiary referral teaching public hospital: a best practice implementation project.

Deep vein thrombosis and pulmonary embolism are known collectively as venous thromboembolism (VTE). These conditions are possible complications in hospitalized patients that can extend hospital stay, result in unplanned readmission, and are associated with long-term disability and death. Despite strong evidence, many patients do not receive optimal thromboprophylaxis. VTE prevention is a top priority in healthcare systems worldwide. The aim of the project was to establish a standardized hospital-wide VTE prevention program and to improve awareness of, and compliance with, best practice standards in the prevention of VTE. A multidisciplinary team utilized the Joanna Briggs Institute Practical Application of Clinical Evidence System program to facilitate the collection of pre and post implementation audit data. The Getting Research into Practice program was also used to conduct a situational analysis to identify barriers, enablers, and implementation strategies while taking into account the context in which the changes were to occur. Hospital-acquired VTE data were collected to monitor the impact, if any, on patient outcomes. The project was conducted in three different phases over a 2.5-year period in an acute care public hospital. A comprehensive suite of professionally crafted guidelines, tools, and resources were developed to facilitate clinician acceptance of evidence-based practices. Comparison of compliance results showed variable improvements with four audit criteria. Formalized patient risk assessment improved to 7.5% with the introduction of a new form. High-risk patients receiving appropriate prophylaxis improved to 81% in medical and 83% in surgical patients, on an existing high background compliance rate. A total of 59% of staff attended a VTE update education in-service. No patients received information about adverse VTE events prior to discharge. The hospital-acquired VTE rate decreased slightly from 0.65 to 0.52 events per 1000 overnight bed days. Overall the project achieved improvements in compliance with best practice standards. A number of delays and barriers contributed to some of the planned interventions not being fully implemented at the time of the follow-up audit. Contributing factors included the lack of electronic capabilities, some processes not being fully embedded into routine clinical workflows, lack of staff time, and identification of an additional organizational barrier relating to practical issues in providing patient education at discharge. A second action cycle is recommended in an attempt to further improve compliance, ensure intervention fidelity, and embed practices into routine daily workflows to positively impact patient and organizational outcomes.

The blood-tendon barrier: identification and characterisation of a novel tissue barrier in tendon blood vessels.

Tissue barriers function as "gate keepers" between different compartments (usually blood and tissue) and are formed by specialised membrane-associated proteins, localising to the apicolateral plasma membrane domain of epithelial and endothelial cells. By sealing the paracellular space, the free diffusion of solutes and molecules across epithelia and endothelia is impeded. Thereby, tissue barriers contribute to the establishment and maintenance of a distinct internal and external environment, which is crucial during organ development and allows maintenance of an organ-specific homeostatic milieu. So far, various epithelial and endothelial tissue barriers have been described, including the blood-brain barrier, the blood-retina barrier, the blood-testis barrier, the blood-placenta barrier, and the cerebrospinal fluid (CSF)-brain barrier, which are vital for physiological function and any disturbance of these barriers can result in severe organ damage or even death. Here, we describe the identification of a novel barrier, located in the vascular bed of tendons, which we term the blood-tendon barrier (BTB). By using immunohistochemistry, transmission electron microscopy, and tracer studies we demonstrate the presence of a functional endothelial barrier within tendons restricting the passage of large blood-borne molecules into the surrounding tendon tissue. We further provide in vitro evidence that the BTB potentially contributes to the creation of a distinct internal tissue environment impacting upon the proliferation and differentiation of tendon-resident cells, effects which might be fundamental for the onset of tendon pathologies.

Analysis of low temperature output parameters for investigation of silicon heterojunction solar cells

This paper presents an ASA simulation analysis of temperature dependent output parameters of the silicon heterojunction (SHJ) solar cell. The analysis has shown that low temperature behaviors of the open circuit voltage and fill factor are strongly connected with the presence of barriers for collection of photogenerated carriers in the SHJ structure. Previous experimentally observed saturation of the open circuit voltage at low temperature was attributed to the presence of a parasitic Schottky barrier at the transparent conductive oxide/amorphous emitter contact. A comprehensive simulation study is provided to describe the mechanism of such saturation and to define the conditions under which the saturation of the open circuit voltage can be used as relevant identification of the parasitic Schottky barrier in SHJ structures with both n-type and p-type amorphous emitters. In addition, the presented study provides the first guideline on the possible utilization of SHJ in low temperature applications such as space applications.

An Integrated Petrophysics and Geomechanics Approach for Fracability Evaluation in Shale Reservoirs

SummaryThe identification of the fracture barrier is important for optimizing horizontal-well drilling, hydraulic fracturing, and protecting fresh aquifer from contamination. The word “brittleness” has been a prevalent descriptor in unconventional-shale-reservoir characterization, but there is no universal agreement regarding its definition. Here, a new definition of mineralogical brittleness is proposed and verified with two independent methods of defining brittleness. Formation with higher brittleness is considered as a good fracturing candidate. However, this viewpoint is not reasonable because brittleness does not indicate rock strength. For instance, the fracture barrier between upper and lower Barnett can be dolomitic limestone with higher brittleness. A new fracability index (FI) is introduced to overcome the shortcoming of brittleness by integrating both brittleness and energy dissipation during hydraulic fracturing. This FI considers that a good fracturing candidate is not only of high brittleness, but also requires less energy to create a new fracture surface. Therefore, the formation with lower FI is considered as a bad fracturing candidate, whereas that with higher fracability is considered as a better target. Logging data from one well in the Barnett shale are applied (1) to verify the principle of the new brittleness definition and FI model and (2) to demonstrate the process of screening hydraulic-fracturing candidates with the FI model.

Activated Pericytes and the Inhibition of Renal Vascular Stability

The hallmark feature of CKD and its progression to end stage is the presence and severity of interstitial fibrosis.1,2 This long-recognized association is the prime driving force of research to understand the nature of renal scarification. Much of the research in this area can be grouped into one of two broad categories: efforts geared toward understanding the biochemical and pathophysiological factors that govern the degree of progression and efforts aimed at defining the cellular and molecular elements that comprise renal scars. With regard to the former, it is clear that a profibrotic environment is promoted by activity from a variety of factors with activity driving the production of extracellular matrix (ECM). Of these, TGFβ and other profibrotic cytokines have been widely studied, and these are enhanced by local tissue injury, epithelial cell cycle arrest, cell differentiation status, or hypoxia.1,3

Identification of specific miRNAs targeting proteins of the apical junctional complex that simulate the probiotic effect of E. coli Nissle 1917 on T84 epithelial cells

In the intestine, dysregulation of miRNA is associated with inflammation, disruption of the gastrointestinal barrier, and the onset of gastrointestinal disorders. This study identifies miRNAs involved in the maintenance of intercellular junctions and barrier integrity. For the functional identification of barrier affecting miRNAs, we took advantage of the barrier-enforcing effects of the probiotic bacterium Escherichia coli Nissle 1917 (EcN) which can be monitored by enhanced transepithelial resistance (TER). miRNA-profiling of T84 monolayers prior and after co-incubation with EcN revealed for the first time differentially regulated miRNAs (miR-203, miR-483-3p, miR-595) targeting tight junction (TJ) proteins. Using real-time PCR, Western blotting and specific miRNA mimics, we showed that these miRNAs are involved in the regulation of barrier function by modulating the expression of regulatory and structural components of tight junctional complexes. Furthermore, specific inhibitors directed at these miRNA abrogated the disturbance of tight junctions induced by enteropathogenic E. coli (EPEC). The half-maximal inhibitory concentration (IC 50) was determined to 340 nM by monitoring inhibitor kinetics. In summary, we conclude that specific miRNAs effect regulatory as well as structural proteins of the junctional complex which in turn are involved in the barrier enhancing effect of EcN. Hence, we suggest that the application of miRNAs might be refined and further developed as a novel supportive strategy for the treatment of gastrointestinal disorders.