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 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.

Accutin, a New Disintegrin, Inhibits Angiogenesis In Vitro and In Vivo by Acting as Integrin vβ3 Antagonist and Inducing Apoptosis

Blood ◽  
1998 ◽  
Vol 92 (9) ◽  
pp. 3268-3276 ◽  
Author(s):  
Chia Hsin Yeh ◽  
Hui-Chin Peng ◽  
Tur-Fu Huang
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Fluorescein Isothiocyanate ◽  
Adenosine Diphosphate ◽  
Tube Formation ◽  
Platelet Glycoprotein ◽  
Dependent Manner ◽  
Antiangiogenic Effect

Abstract Endothelial integrins play an essential role in angiogenesis and cell survival. Accutin, a new member of disintegrin family derived from venom of Agkistrodon acutus, potently inhibited human platelet aggregation caused by various agonists (eg, thrombin, collagen, and, adenosine diphosphate [ADP]) through the blockade of fibrinogen binding to platelet glycoprotein IIb/IIIa (ie, integrin IIbβ3). In this report, we describe that accutin specifically inhibited the binding of monoclonal antibody (MoAb) 7E3, which recognizes integrin vβ3, to human umbilical vein endothelial cells (HUVECs), but not those of other anti-integrin MoAbs such as 2β1, 3β1, and 5β1. Moreover, accutin, but not the control peptide GRGES, dose-dependently inhibited the 7E3 interaction with HUVECs. Both 7E3 and GRGDS, but not GRGES or Integrelin, significantly blocked fluorescein isothiocyanate-conjugated accutin binding to HUVEC. In functional studies, accutin exhibited inhibitory effects on HUVEC adhesion to immobilized fibrinogen, fibronectin and vitronectin, and the capillary-like tube formation on Matrigel in a dose- and RGD-dependent manner. In addition, it exhibited an effective antiangiogenic effect in vivo when assayed by using the 10-day-old embryo chick CAM model. Furthermore, it potently induced HUVEC apoptotic DNA fragmentation as examined by electrophoretic and flow cytometric assays. In conclusion, accutin inhibits angiogenesis in vivo and in vitro by blocking integrin vβ3 of endothelial cells and by inducing apoptosis. The antiangiogenic activity of disintegrins might be explored as the target of developing the potential antimetastatic agents. © 1998 by The American Society of Hematology.

Pentoxifylline inhibits FMLP-induced macromolecular leakage

1995 ◽  
Vol 269 (1) ◽  
pp. H239-H245
Author(s):  
K. Nakagawa ◽  
F. N. Miller ◽  
A. W. Knott ◽  
M. J. Edwards
Keyword(s):  
Inflammatory Responses ◽  
Fluorescein Isothiocyanate ◽  
Histamine Receptor ◽  
Intracellular Camp ◽  
Dependent Manner ◽  
Cyclic Monophosphate ◽  
Endogenous Histamine ◽  
Camp Analogue

The acute inflammatory responses to the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) and the effects of pentoxifylline (PTXF) on the responses in vivo were studied. We used intravital microscopy with rat cremaster muscle preparation to determine inflammatory responses of microcirculation. Macromolecular leakage from postcapillary venules was evaluated by quantifying the extravasation of fluorescein isothiocyanate conjugated to bovine serum albumin. FMLP induced a rapid increase in macromolecular leakage, an increase in leukocyte-endothelium adhesion, and a decrease in blood flow in the microcirculation. PTXF inhibited FMLP-induced responses in a dose-dependent manner but failed to block the histamine-dependent leakage induced by compound 48/80. In addition, diphenhydramine, a histamine-receptor blocker, did not affect the macromolecular leakage induced by FMLP. The cell-permeable adenosine 3',5'-cyclic monophosphate (cAMP) analogue N6,2'-O-dibutyryladenosine 3',5'-cyclic monophosphate mimicked PTXF's effects on the microcirculation and also inhibited FMLP-induced macromolecular leakage. PTXF is known to inhibit phosphodiesterase and increase intracellular cAMP, which modulates functions of endothelial cells, smooth muscle cells, and neutrophils in vitro. Our findings suggest that FMLP induces acute inflammatory responses through activation of neutrophils, independent of endogenous histamine release, and that PTXF inhibits these responses through elevated intracellular cAMP.

scholarly journals A Novel Role of A2AR in the Maintenance of Intestinal Barrier Function of Eteric Glia from Hypoxia-Induced Injury by Combining with mGluR5

2021 ◽  
Vol 12 ◽  
Author(s):  
Lihua Sun ◽  
Xiang Li ◽  
Haidi Guan ◽  
Shuaishuai Chen ◽  
Xin Fan ◽  
...  
Keyword(s):  
Metabotropic Glutamate Receptor ◽  
Ischemia Reperfusion ◽  
Intestinal Barrier ◽  
Intestinal Barrier Function ◽  
Metabotropic Glutamate ◽  
Enteric Glial Cells ◽  
Intestinal Ischemia Reperfusion

During acute intestinal ischemia reperfusion (IR) injury, the intestinal epithelial barrier (IEB) function is often disrupted. Enteric glial cells (EGCs) play an important role in maintaining the integrity of IEB functions. However, how EGCs regulate IEB function under IR stimulation is unknown. The present study reveals that the adenosine A2A receptor (A2AR) is important for mediating the barrier-modulating roles of EGCs. A2AR knockout (KO) experiments revealed more serious intestinal injury in A2AR KO mice than in WT mice after IR stimulation. Moreover, A2AR expression was significantly increased in WT mice when challenged by IR. To further investigate the role of A2AR in IEB, we established an in vitro EGC-Caco-2 co-culture system. Hypoxia stimulation was used to mimic the process of in vivo IR. Treating EGCs with the CGS21680 A2AR agonist attenuated hypoxia-induced intestinal epithelium damage through up-regulating ZO-1 and occludin expression in cocultured Caco-2 monolayers. Furthermore, we showed that A2AR and metabotropic glutamate receptor 5 (mGluR5) combine to activate the PKCα-dependent pathway in conditions of hypoxia. This study shows, for the first time, that hypoxia induces A2AR-mGluR5 interaction in EGCs to protect IEB function via the PKCα pathway.

scholarly journals Duodenum Intestine-Chip for preclinical drug assessment in a human relevant model

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Magdalena Kasendra ◽  
Raymond Luc ◽  
Jianyi Yin ◽  
Dimitris V Manatakis ◽  
Gauri Kulkarni ◽  
...  
Keyword(s):  
Drug Transport ◽  
Intestinal Barrier ◽  
New Drugs ◽  
Intestinal Barrier Function ◽  
Human Pharmacokinetics ◽  
Relevant Model ◽  
Cell Subpopulations ◽  
And Function

Induction of intestinal drug metabolizing enzymes can complicate the development of new drugs, owing to the potential to cause drug-drug interactions (DDIs) leading to changes in pharmacokinetics, safety and efficacy. The development of a human-relevant model of the adult intestine that accurately predicts CYP450 induction could help address this challenge as species differences preclude extrapolation from animals. Here, we combined organoids and Organs-on-Chips technology to create a human Duodenum Intestine-Chip that emulates intestinal tissue architecture and functions, that are relevant for the study of drug transport, metabolism, and DDI. Duodenum Intestine-Chip demonstrates the polarized cell architecture, intestinal barrier function, presence of specialized cell subpopulations, and in vivo relevant expression, localization, and function of major intestinal drug transporters. Notably, in comparison to Caco-2, it displays improved CYP3A4 expression and induction capability. This model could enable improved in vitro to in vivo extrapolation for better predictions of human pharmacokinetics and risk of DDIs.

Aflatoxina M1 e Aflatoxina B1-lisina como Biomarcadores de Avaliação da Eficiência de Adsorventes para Aflatoxinas: Artigo de Revisão

2018 ◽  
Vol 22 (3) ◽  
pp. 171 ◽  
Author(s):  
Roice Eliana Rosim ◽  
Carlos Augusto Fernandes de Oliveira ◽  
Carlos Humberto Corassin
Keyword(s):  
Aflatoxin B1 ◽  
Animal Feed ◽  
Biological Fluids ◽  
Animal Health ◽  
Google Scholar ◽  
Aflatoxin M1 ◽  
Published Data ◽  
The Individual

A contaminação de alimentos por aflatoxinas, principalmente, a aflatoxina B1 (AFB1) representa um problema mundial para a saúde humana e animal. Uma forma de avaliar a exposição a estes contaminantes é analisando a dieta para verificar a ocorrência destes compostos. Esta metodologia, no entanto, tem limitações devido à variabilidade das aflatoxinas encontradas nos alimentos e às diferenças individuais na toxicocinética dos compostos. Por outro lado, o biomonitoramento de aflatoxinas em fluidos biológicos se utilizando de biomarcadores gera informações mais confiáveis sobre a exposição a estas toxinas nos indivíduos. O uso de adsorventes químicos na ração animal possibilita a detoxificação de aflatoxinas sem produzir efeitos tóxicos nem alterar as propriedades nutricionais. Este trabalho teve por objetivo revisar os dados publicados sobre a eficiência in vitro e in vivo de adsorventes para aflatoxinas, bem como estudos referentes ao uso da aflatoxina M1 (AFM1) e da AFB1-lisina como biomarcadores para avaliar a redução da biodisponibilidade da AFB1 por adsorventes em rações. Trabalhos relevantes publicados nos últimos dez anos (2009-presente) foram selecionados nas bases de dados PubMed, Science Direct e Google Scholar. A determinação de AFM1 no leite e/ou na urina, bem como de AFB1-lisina no soro, indica a biodisponibilidade individual da AFB1 em ensaios para avaliar a eficiência de adsorventes em animais. Deste modo, a utilização destes biomarcadores permite reduzir os custos dos ensaios in vivo, além de proporcionar maior padronização dos experimentos e possibilitar a avaliação da eficiência dos adsorventes em condições de campo. Palavras chave: AFB1. - Adsorventes Minerais. Biomarcadores de Exposição - AFB1-lisina - AFM1           AbstractFood contamination by aflatoxins, mainly aflatoxin B1 (AFB1), is a worldwide concern for human and animal health. A possible way to assess the exposure to these contaminants is through the diet analyses to verify the occurrence of mycotoxins. However, this methodology has important limitations due to the variability of mycotoxins found in the food and the individual differences in the toxicokinetics of the compounds. On the other hand, biomonitoring of aflatoxins in biological fluids using biomarkers generates more reliable information on the exposure to these toxins in individuals. The use of chemical adsorbents in animal feed makes it possible to detoxify mycotoxins without producing toxic effects or altering the nutritional properties. The aim of this study was to revise the available published data on the in vitro and in vivo efficacy of adsorbents for aflatoxins, as well as studies on the use of aflatoxin M1 (AFM1) and AFB1-lysine as biomarkers to evaluate the reduction in the bioavailability of AFB1 by adsorbents in feed. Relevant articles published in the last 10 years (2009-present) were selected in PubMed, Science Direct and Google Scholar. Determination of AFM1 in milk and/or urine, and AFB1-lysine in serum, indicate the individual bioavailability of AFB1 in trials conducted for evaluation of adsorbent’s efficiency in animals. Thus, the use of these biomarkers may reduce the costs of in vivo trials, increase the standardization of experiments, and evaluate the adsorbents’ efficiency under field conditions. Keywords: Aflatoxin B1 – Clays - Exposure Biomarkers - Aflatoxin B1-lysine Aflatoxin M1. 

Challenges in translational research on probiotic lactobacilli: from in vitro assays to clinical trials

2013 ◽  
Vol 4 (1) ◽  
pp. 83-100 ◽  
Author(s):  
M. Meijerink ◽  
A. Mercenier ◽  
J.M. Wells
Keyword(s):  
Translational Research ◽  
Selection Criteria ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Intestinal Barrier ◽  
Probiotic Strain ◽  
In Vitro Assays ◽  
Intestinal Barrier Function

Beneficial effects of certain probiotic strains have been established in the treatment and prevention of various immune and intestinal disorders in humans, including allergic diseases, chronic inflammatory diseases and diarrhoea. The proposed mechanisms underlying the immunomodulatory effects of probiotics in humans are not understood in precise detail but include enhancement of intestinal barrier function, altered epithelial signalling, competition with pathogens and effects on immune cells and immunity depending on the probiotic strain. The publication of controversial or inconclusive probiotic studies in humans highlights the need for a better understanding of the mechanisms and improved strain selection criteria. This review focuses on the immunomodulatory properties of lactobacilli and bifidobacteria in vitro and in vivo, current knowledge concerning the mechanisms in vivo and challenges in translational research on probiotics. A better understanding of the molecular mechanisms of probiotics, the effect of probiotic mixtures versus single strains, the effect of formulation of probiotics and the fate of ingested probiotics should help to clarify the value of immune assays as selection criteria for probiotics.

scholarly journals Probiotic Associated Therapeutic Curli Hybrids (PATCH)

2018 ◽  
Author(s):  
Pichet Praveschotinunt ◽  
Anna M. Duraj-Thatte ◽  
Ilia Gelfat ◽  
Franziska Bahl ◽  
David B. Chou ◽  
...  
Keyword(s):  
Barrier Function ◽  
Unmet Need ◽  
Intestinal Barrier ◽  
Genetically Engineered ◽  
Intestinal Barrier Function ◽  
Beneficial Bacteria ◽  
Fibrous Matrix

AbstractThere is an unmet need for new treatment methods for inflammatory bowel disease (IBD) that can reliably maintain remission without leading to detrimental side effects. Beneficial bacteria have been utilized as an alternative treatment for IBD albeit with low efficacy. We genetically engineered Escherichia coli Nissle 1917 (EcN) to create an anti-inflammatory fibrous matrix in situ. This matrix consists of EcN-produced curli nanofibers displaying trefoil factors (TFFs), known to promote intestinal barrier function and epithelial restitution. We confirmed that engineered EcN was able to secrete the curli-fused TFFs in vitro and in vivo, and was non-pathogenic. We observed an enhanced protective effect of engineered EcN against dextran sodium sulfate induced colitis in mice, associated with barrier function reinforcement and immunomodulation. This work sets the foundation for the development of a novel therapeutic platform in which the in situ production of a therapeutic protein matrix from beneficial bacteria can be exploited.

Accutin, a New Disintegrin, Inhibits Angiogenesis In Vitro and In Vivo by Acting as Integrin vβ3 Antagonist and Inducing Apoptosis

Blood ◽  
1998 ◽  
Vol 92 (9) ◽  
pp. 3268-3276 ◽  
Author(s):  
Chia Hsin Yeh ◽  
Hui-Chin Peng ◽  
Tur-Fu Huang
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Fluorescein Isothiocyanate ◽  
Adenosine Diphosphate ◽  
Tube Formation ◽  
Platelet Glycoprotein ◽  
Dependent Manner ◽  
Antiangiogenic Effect

Endothelial integrins play an essential role in angiogenesis and cell survival. Accutin, a new member of disintegrin family derived from venom of Agkistrodon acutus, potently inhibited human platelet aggregation caused by various agonists (eg, thrombin, collagen, and, adenosine diphosphate [ADP]) through the blockade of fibrinogen binding to platelet glycoprotein IIb/IIIa (ie, integrin IIbβ3). In this report, we describe that accutin specifically inhibited the binding of monoclonal antibody (MoAb) 7E3, which recognizes integrin vβ3, to human umbilical vein endothelial cells (HUVECs), but not those of other anti-integrin MoAbs such as 2β1, 3β1, and 5β1. Moreover, accutin, but not the control peptide GRGES, dose-dependently inhibited the 7E3 interaction with HUVECs. Both 7E3 and GRGDS, but not GRGES or Integrelin, significantly blocked fluorescein isothiocyanate-conjugated accutin binding to HUVEC. In functional studies, accutin exhibited inhibitory effects on HUVEC adhesion to immobilized fibrinogen, fibronectin and vitronectin, and the capillary-like tube formation on Matrigel in a dose- and RGD-dependent manner. In addition, it exhibited an effective antiangiogenic effect in vivo when assayed by using the 10-day-old embryo chick CAM model. Furthermore, it potently induced HUVEC apoptotic DNA fragmentation as examined by electrophoretic and flow cytometric assays. In conclusion, accutin inhibits angiogenesis in vivo and in vitro by blocking integrin vβ3 of endothelial cells and by inducing apoptosis. The antiangiogenic activity of disintegrins might be explored as the target of developing the potential antimetastatic agents.© 1998 by The American Society of Hematology.

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