scholarly journals Heterogeneous expression of Pil3 pilus is critical for Streptococcus gallolyticus translocation across polarized colonic epithelial monolayers

2019 ◽  
Author(s):  
Mariana Martins ◽  
Laurence du Merle ◽  
Patrick Trieu-Cuot ◽  
Shaynoor Dramsi
Keyword(s):  
Intestinal Barrier ◽  
Opportunistic Pathogen ◽  
Oral Route ◽  
Elderly Persons ◽  
Dependent Manner ◽  
Bacterial Surface ◽  
Streptococcus Gallolyticus ◽  
Heterogeneous Expression ◽  
Colonic Cells

ABSTRACTStreptococcus gallolyticus subspecies gallolyticus (Sgg) is an opportunistic pathogen responsible for septicaemia and endocarditis in elderly persons. Sgg is also a commensal of the human gastrointestinal tract. Here we demonstrate that Sgg strain UCN34 translocates across tight intestinal barriers in vitro in a Pil3-dependent manner. Confocal images of UCN34 passage across human colonic cells reveals that Sgg utilizes a paracellular pathway. Pil3 was previously shown to be expressed heterogeneously and WT UCN34 consists of about 90% of Pil3low and 10% of Pil3high cells. We found that both the Δpil3 mutant and the Pil3+ overexpressing variant could not translocate across Caco-2 and T84 barriers. Interestingly, combining live Δpil3 mutant cells with fixed Pil3+ variants in a 10:1 ratio (mimicking UCN34 WT population) allowed efficient translocation of the Δpil3 mutant. These experiments demonstrate that heterogeneous expression of Pil3 plays a key role in optimal translocation of Sgg across the intestinal barrier.ABSTRACT IMPORTANCEStreptococcus gallolyticus subsp. gallolyticus (Sgg) is an opportunistic pathogen responsible for septicemia and infective endocarditis in elderly persons. Sgg is a commensal of the rumen of herbivores and transmission to humans most probably occurs through the oral route. In this work, we have studied how this bacterium crosses the intestinal barrier using well-known in vitro models. Confocal microscopy images revealed that Sgg UCN34 can traverse the epithelial monolayer in between adjacent cells. We next showed that passage of Sgg from the apical to the basolateral compartment is dependent on the heterogenous expression of the Pil3 pilus at the bacterial surface. We hypothesize that Pil3high cocci adhere firmly to epithelial cells to activate transient opening of tight junctions thereby allowing the traversal of Pil3low bacteria.

scholarly journals Streptococcus gallolyticus Increases Expression and Activity of Aryl Hydrocarbon Receptor-Dependent CYP1 Biotransformation Capacity in Colorectal Epithelial Cells

2021 ◽  
Vol 11 ◽  
Author(s):  
Rahwa Taddese ◽  
Rian Roelofs ◽  
Derk Draper ◽  
Xinqun Wu ◽  
Shaoguang Wu ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Aryl Hydrocarbon Receptor ◽  
Specific Inhibitor ◽  
Intestinal Bacteria ◽  
Opportunistic Pathogen ◽  
Dependent Manner ◽  
Aryl Hydrocarbon ◽  
Streptococcus Gallolyticus

ObjectiveThe opportunistic pathogen Streptococcus gallolyticus is one of the few intestinal bacteria that has been consistently linked to colorectal cancer (CRC). This study aimed to identify novel S. gallolyticus-induced pathways in colon epithelial cells that could further explain how S. gallolyticus contributes to CRC development.Design and ResultsTranscription profiling of in vitro cultured CRC cells that were exposed to S. gallolyticus revealed the specific induction of oxidoreductase pathways. Most prominently, CYP1A and ALDH1 genes that encode phase I biotransformation enzymes were responsible for the detoxification or bio-activation of toxic compounds. A common feature is that these enzymes are induced through the Aryl hydrocarbon receptor (AhR). Using the specific inhibitor CH223191, we showed that the induction of CYP1A was dependent on the AhR both in vitro using multiple CRC cell lines as in vivo using wild-type C57bl6 mice colonized with S. gallolyticus. Furthermore, we showed that CYP1 could also be induced by other intestinal bacteria and that a yet unidentified diffusible factor from the S. galloltyicus secretome (SGS) induces CYP1A enzyme activity in an AhR-dependent manner. Importantly, priming CRC cells with SGS increased the DNA damaging effect of the polycyclic aromatic hydrocarbon 3-methylcholanthrene.ConclusionThis study shows that gut bacteria have the potential to modulate the expression of biotransformation pathways in colonic epithelial cells in an AhR-dependent manner. This offers a novel theory on the contribution of intestinal bacteria to the etiology of CRC by modifying the capacity of intestinal epithelial or (pre-)cancerous cells to (de)toxify dietary components, which could alter intestinal susceptibility to DNA damaging events.

scholarly journals Lubiprostone Induces Claudin-1 and Protects Intestinal Barrier Function

Pharmacology ◽  
2019 ◽  
Vol 105 (1-2) ◽  
pp. 102-108 ◽  
Author(s):  
Norio Nishii ◽  
Tadayuki Oshima ◽  
Min Li ◽  
Hirotsugu Eda ◽  
Kumiko Nakamura ◽  
...  
Keyword(s):  
Barrier Function ◽  
Intestinal Barrier ◽  
Fluorescein Isothiocyanate ◽  
Intestinal Barrier Function ◽  
Epithelial Barrier ◽  
Dependent Manner ◽  
Epithelial Permeability ◽  
Epithelial Barrier Function ◽  
Dose Dependent

Introduction: Lubiprostone, a chloride channel activator, is said to reduce epithelial permeability. However, whether lubiprostone has a direct effect on the epithelial barrier function and how it modulates the intestinal barrier function remain unknown. Therefore, the effects of lubiprostone on intestinal barrier function were evaluated in vitro. Methods: Caco-2 cells were used to assess the intestinal barrier function. To examine the expression of claudins, immunoblotting was performed with specific antibodies. The effects of lubiprostone on cytokines (IFNγ, IL-6, and IL-1β) and aspirin-induced epithelial barrier disruption were assessed by transepithelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC) labeled-dextran permeability. Results: IFNγ, IL-6, IL-1β, and aspirin significantly decreased TEER and increased epithelial permeability. Lubiprostone significantly improved the IFNγ-induced decrease in TEER in a dose-dependent manner. Lubiprostone significantly reduced the IFNγ-induced increase in FITC labeled-dextran permeability. The changes induced by IL-6, IL-1β, and aspirin were not affected by lubiprostone. The expression of claudin-1, but not claudin-3, claudin-4, occludin, and ZO-1 was significantly increased by lubiprostone. Conclusion: Lubiprostone significantly improved the IFNγ-induced decrease in TEER and increase in FITC labeled-dextran permeability. Lubiprostone increased the expression of claudin-1, and this increase may be related to the effect of lubiprostone on the epithelial barrier function.

Nanocargos: A Burgeoning Quest in Cancer Management

2020 ◽  
Vol 10 (2) ◽  
pp. 149-163
Author(s):  
Atul Jain ◽  
Teenu Sharma ◽  
Sumant Saini ◽  
Om Prakash Katare ◽  
Vandana. Soni ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Oral Delivery ◽  
Imaging Techniques ◽  
Intestinal Barrier ◽  
Oral Route ◽  
In Vitro Models ◽  
In Vitro Toxicity ◽  
Cancer Management ◽  
Surface Modified

Cancer, a complex series of diseased conditions, contributes to a significant health problem and is a leading cause of mortalities across the world. Lately, with the advent of improved diagnostics and imaging techniques, and newer advanced oral chemotherapeutics; millions of cancer affected people can lengthen their life span. Despite all the challenges associated with an active chemotherapeutic molecule like microenvironment and the intestinal barrier of the gastrointestinal tract (GIT) etc., the oral delivery remains the most acceptable route of drug administration. In this regard, nanotechnology has played a significant role in the counteracting the challenges encountered with newly developed molecules and aiding in improving their bioavailability and targetability to the tumour site, while administering through the oral route. Several literature instances document the usage of nanostructured drug delivery systems such as lipid-based, polymerbased or metallic nanomaterials to improve the efficacy of chemotherapy. Besides, sitespecific targeted surface-modified drug delivery system designed to deliver the active molecule has opened up to the newer avenues of nanotechnology. However, the issue of potential toxicity allied with nanotechnology cannot be compromised and thus, needs specific ethical regulations and guidelines. The various in vitro models have been developed to evaluate the in vitro toxicity profile which can be further correlated with the invivo model. Thus, this review provides a summarized account of the various aspects related to the role of nanotechnology in cancer therapy and various related issues thereof; that must be triumphed over to apprehend its full promise.

scholarly journals Aflatoxin B1 and Aflatoxin M1 Induce Compromised Intestinal Integrity through Clathrin-Mediated Endocytosis

Toxins ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 184
Author(s):  
Yanan Gao ◽  
Xiaoyu Bao ◽  
Lu Meng ◽  
Huimin Liu ◽  
Jiaqi Wang ◽  
...  
Keyword(s):  
Aflatoxin B1 ◽  
Intestinal Barrier ◽  
Fluorescein Isothiocyanate ◽  
Intestinal Barrier Function ◽  
Aflatoxin M1 ◽  
Dependent Manner ◽  
Simultaneous Exposure ◽  
Intestinal Integrity

With the growing diversity and complexity of diet, humans are at risk of simultaneous exposure to aflatoxin B1 (AFB1) and aflatoxin M1 (AFM1), which are well-known contaminants in dairy and other agricultural products worldwide. The intestine represents the first barrier against external contaminants; however, evidence about the combined effect of AFB1 and AFM1 on intestinal integrity is lacking. In vivo, the serum biochemical parameters related to intestinal barrier function, ratio of villus height/crypt depth, and distribution pattern of claudin-1 and zonula occluden-1 were significantly affected in mice exposed to 0.3 mg/kg b.w. AFB1 and 3.0 mg/kg b.w. AFM1. In vitro results on differentiated Caco-2 cells showed that individual and combined AFB1 (0.5 and 4 μg/mL) and AFM1 (0.5 and 4 μg/mL) decreased cell viability and trans-epithelial electrical resistance values as well as increased paracellular permeability of fluorescein isothiocyanate-dextran in a dose-dependent manner. Furthermore, AFM1 aggravated AFB1-induced compromised intestinal barrier, as demonstrated by the down-regulation of tight junction proteins and their redistribution, particularly internalization. Adding the inhibitor chlorpromazine illustrated that clathrin-mediated endocytosis partially contributed to the compromised intestinal integrity. Synergistic and additive effects were the predominant interactions, suggesting that these toxins are likely to have negative effects on human health.

scholarly journals A Novel Indole Compound That Inhibits Pseudomonas aeruginosa Growth by Targeting MreB Is a Substrate for MexAB-OprM

2007 ◽  
Vol 189 (19) ◽  
pp. 6870-6881 ◽  
Author(s):  
Gregory T. Robertson ◽  
Timothy B. Doyle ◽  
Qun Du ◽  
Leonard Duncan ◽  
Khisimuzi E. Mdluli ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agents ◽  
Opportunistic Pathogen ◽  
Binding Pocket ◽  
Cross Resistance ◽  
Dependent Manner ◽  
Intrinsic Resistance ◽  
Outer Membrane Channel

ABSTRACT Drug efflux systems contribute to the intrinsic resistance of Pseudomonas aeruginosa to many antibiotics and biocides and hamper research focused on the discovery and development of new antimicrobial agents targeted against this important opportunistic pathogen. Using a P. aeruginosa PAO1 derivative bearing deletions of opmH, encoding an outer membrane channel for efflux substrates, and four efflux pumps belonging to the resistance nodulation/cell division class including mexAB-oprM, we identified a small-molecule indole-class compound (CBR-4830) that is inhibitory to growth of this efflux-compromised strain. Genetic studies established MexAB-OprM as the principal pump for CBR-4830 and revealed MreB, a prokaryotic actin homolog, as the proximal cellular target of CBR-4830. Additional studies establish MreB as an essential protein in P. aeruginosa, and efflux-compromised strains treated with CBR-4830 transition to coccoid shape, consistent with MreB inhibition or depletion. Resistance genetics further suggest that CBR-4830 interacts with the putative ATP-binding pocket in MreB and demonstrate significant cross-resistance with A22, a structurally unrelated compound that has been shown to promote rapid dispersion of MreB filaments in vivo. Interestingly, however, ATP-dependent polymerization of purified recombinant P. aeruginosa MreB is blocked in vitro in a dose-dependent manner by CBR-4830 but not by A22. Neither compound exhibits significant inhibitory activity against mutant forms of MreB protein that bear mutations identified in CBR-4830-resistant strains. Finally, employing the strains and reagents prepared and characterized during the course of these studies, we have begun to investigate the ability of analogues of CBR-4830 to inhibit the growth of both efflux-proficient and efflux-compromised P. aeruginosa through specific inhibition of MreB function.

scholarly journals Bioavailability of arsenic, cadmium, lead and mercury as measured by intestinal permeability

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shiv Bolan ◽  
Balaji Seshadri ◽  
Simon Keely ◽  
Anitha Kunhikrishnan ◽  
Jessica Bruce ◽  
...  
Keyword(s):  
Intestinal Permeability ◽  
Chelating Agents ◽  
Intestinal Barrier ◽  
Gut Bacteria ◽  
Apparent Permeability ◽  
Gut Microbes ◽  
Bacterial Surface ◽  
Apparent Permeability Coefficient ◽  
Cadmium Lead

AbstractIn this study, the intestinal permeability of metal(loid)s (MLs) such as arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) was examined, as influenced by gut microbes and chelating agents using an in vitro gastrointestinal/Caco-2 cell intestinal epithelium model. The results showed that in the presence of gut microbes or chelating agents, there was a significant decrease in the permeability of MLs (As-7.5%, Cd-6.3%, Pb-7.9% and Hg-8.2%) as measured by apparent permeability coefficient value (Papp), with differences in ML retention and complexation amongst the chelants and the gut microbes. The decrease in ML permeability varied amongst the MLs. Chelating agents reduce intestinal absorption of MLs by forming complexes thereby making them less permeable. In the case of gut bacteria, the decrease in the intestinal permeability of MLs may be associated to a direct protection of the intestinal barrier against the MLs or indirect intestinal ML sequestration by the gut bacteria through adsorption on bacterial surface. Thus, both gut microbes and chelating agents can be used to decrease the intestinal permeability of MLs, thereby mitigating their toxicity.

scholarly journals Commensal Pseudomonas fluorescens protect Arabidopsis from closely-related Pseudomonas pathogens in a colonization-dependent manner

2021 ◽  
Author(s):  
Nicole R. Wang ◽  
Ryan A. Melnyk ◽  
Christina L. Wiesmann ◽  
Sarzana S. Hossain ◽  
Myoung-Hwan Chi ◽  
...  
Keyword(s):  
Soil Microorganisms ◽  
Competitive Exclusion ◽  
Response Regulator ◽  
Brown Rot ◽  
Opportunistic Pathogen ◽  
Dependent Manner ◽  
Antimicrobial Compounds ◽  
In Planta ◽  
Soil Systems

AbstractPlants form commensal associations with soil microorganisms, creating a root microbiome that provides benefits to the host including protection against pathogens. While bacteria can inhibit pathogens through production of antimicrobial compounds in vitro, it is largely unknown how microbiota contribute to pathogen protection in planta. We developed a gnotobiotic model system consisting of Arabidopsis thaliana, and an opportunistic pathogen Pseudomonas sp. N2C3, to identify mechanisms that determine the outcome of plant-pathogen-microbiome interactions in the rhizosphere. We screened 25 phylogenetically diverse Pseudomonas strains for their ability to protect against N2C3 and found that commensal strains closely related to N2C3 were more likely to protect against pathogenesis. We used a comparative genomics approach to identify unique genes in the protective strains that revealed no genes that correlate with protection, suggesting that variable regulation of components of the core Pseudomonas genome may contribute to pathogen protection. We found that commensal colonization level was highly predictive of protection and so tested deletions in genes previously shown to be required for Arabidopsis rhizosphere colonization. We identified a response regulator colR that is required for Pseudomonas protection from N2C3 and fitness in competition with N2C3 indicating that competitive exclusion may contribute to pathogen protection. We found that Pseudomonas WCS365 also protects against the agricultural pathogen Pseudomonas fuscovaginae SE-1, the causal agent of bacterial sheath brown rot of rice. This work establishes a gnotobiotic model to uncover mechanisms by which members of the microbiome can protect hosts from pathogens and informs our understanding of the use of beneficial strains for microbiome engineering in dysbiotic soil systems.

scholarly journals Antimicrobial Peptides Human Beta-Defensin-2 and -3 Protect the Gut During Candida albicans Infections Enhancing the Intestinal Barrier Integrity: In Vitro Study

2021 ◽  
Vol 11 ◽  
Author(s):  
Alessandra Fusco ◽  
Vittoria Savio ◽  
Maria Donniacuo ◽  
Brunella Perfetto ◽  
Giovanna Donnarumma
Keyword(s):  
Candida Albicans ◽  
Epithelial Cells ◽  
Antimicrobial Peptides ◽  
Intestinal Barrier ◽  
In Vitro Study ◽  
Opportunistic Pathogen ◽  
Mucosal Barrier ◽  
Apoptotic Pathway ◽  
Intestinal Pathogens

The intestinal mucosa is composed of a monolayer of epithelial cells, which is highly polarized and firmly united to each other thanks to the presence of proteins complexes, called Tight junctions (TJs). Alteration of the mucus layer and TJs causes an increase in intestinal permeability, which can lead to a microbial translocation and systemic disorders. Candida albicans, in addition to its role of commensal, is an opportunistic pathogen responsible for disseminated candidiasis, especially in immunocompromised subjects where the dysbiosis leads to damage of the intestinal mucosal barrier . In this work, we used a line of intestinal epithelial cells able to stably express the genes that encodes human beta defensin-2 (HBD-2) and -3 (HBD-3) to monitor the invasion of C. albicans in vitro. Defensins are a group of antimicrobial peptides (AMPs) found in different living organisms, and are involved in the first line of defense in the innate immune response against pathogens. The results obtained show that the presence of antimicrobial peptides improves the expression of TJs and increases the Trans Epithelial Electrical Resistence value. In addition, the invasive ability of C. albicans in transfected cells is significantly reduced, as well as the expression levels of genes involved in the apoptotic pathway. Through the study of interaction between antimicrobial peptides and microbiota we will be able in the future to better understand the mechanisms by which they exert the host defense function against intestinal pathogens.

scholarly journals Interaction between Miltefosine and Amphotericin B: Consequences for Their Activities towards Intestinal Epithelial Cells and Leishmania donovani Promastigotes In Vitro

2006 ◽  
Vol 50 (11) ◽  
pp. 3793-3800 ◽  
Author(s):  
Cécile Ménez ◽  
Marion Buyse ◽  
Madeleine Besnard ◽  
Robert Farinotti ◽  
Philippe M. Loiseau ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Leishmania Donovani ◽  
Biological Activities ◽  
Intestinal Barrier ◽  
Oral Route ◽  
Transepithelial Transport ◽  
Physicochemical Interaction ◽  
Cell Monolayers ◽  
Permeability Enhancement

ABSTRACT The aim of this study was to evaluate the potential of a combination of two antileishmanial drugs, miltefosine (HePC) and amphotericin B (AMB), when administered by the oral route. Caco-2 cell monolayers were used as a validated in vitro model of the intestinal barrier and Leishmania donovani promastigotes as a model for evaluating the effect of the drug combination. Spectroscopic measurements demonstrated that HePC and AMB associate, leading to the formation of mixed aggregates in which AMB is solubilized as monomers. The incubation of the association of HePC and AMB with Caco-2 cell monolayers, at a concentration higher than 5 μM, led to (i) a reduction of the HePC-induced paracellular permeability enhancement in Caco-2 cell monolayers, (ii) an inhibition of the uptake of both drugs, and (iii) a decrease in the transepithelial transport of both drugs, suggesting that a pharmacokinetic antagonism between HePC and AMB could occur after their oral administration. However, the combination did not exhibit any antagonism or synergy in its antileishmanial activity. These results demonstrated a strong physicochemical interaction between HePC and AMB, depending on the concentration of each, which could have important consequences for their biological activities, if they are administered together.

scholarly journals PilT and PilU are homohexameric ATPases that coordinate to retract type IVa pili

2019 ◽  
Author(s):  
Jennifer L. Chlebek ◽  
Hannah Q. Hughes ◽  
Aleksandra S. Ratkiewicz ◽  
Rasman Rayyan ◽  
Joseph Che-Yen Wang ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Dependent Manner ◽  
Acinetobacter Baylyi ◽  
Bacterial Surface ◽  
Type Iv ◽  
Bona Fide ◽  
Almost All

AbstractBacterial type IV pili are critical for diverse biological processes including horizontal gene transfer, surface sensing, biofilm formation, adherence, motility, and virulence. These dynamic appendages extend and retract from the cell surface. In many type IVa pilus systems, extension occurs through the action of an extension ATPase, often called PilB, while optimal retraction requires the action of a retraction ATPase, PilT. Many type IVa systems also encode a homolog of PilT called PilU. However, the function of this protein has remained unclear becausepilUmutants exhibit inconsistent phenotypes among type IV pilus systems and because it is relatively understudied compared to PilT. Here, we study the type IVa competence pilus ofVibrio choleraeas a model system to define the role of PilU. We show that the ATPase activity of PilU is critical for pilus retraction in PilT Walker A and/or Walker B mutants. PilU does not, however, contribute to pilus retraction in ΔpilTstrains. Thus, these data suggest that PilU is abona fideretraction ATPase that supports pilus retraction in a PilT-dependent manner. We also found that a ΔpilUmutant exhibited a reduction in the force of retraction suggesting that PilU is important for generating maximal retraction forces. Additionalin vitroandin vivodata show that PilT and PilU act as independent homo-hexamers that may form a complex to facilitate pilus retraction. Finally, we demonstrate that the role of PilU as a PilT-dependent retraction ATPase is conserved inAcinetobacter baylyi, suggesting that the role of PilU described here may be broadly applicable to other type IVa pilus systems.Author SummaryAlmost all bacterial species use thin surface appendages called pili to interact with their environments. These structures are critical for the virulence of many pathogens and represent one major way that bacteria share DNA with one another, which contributes to the spread of antibiotic resistance. To carry out their function, pili dynamically extend and retract from the bacterial surface. Here, we show that retraction of pili in some systems is determined by the combined activity of two motor ATPase proteins.

Sign in / Sign up

Export Citation Format

Share Document