scholarly journals A206 SUSCEPTIBILITY OF HNF4AΔIEC MICE TO SALMONELLA INFECTIONS

2020 ◽  
Vol 3 (Supplement_1) ◽  
pp. 78-79
Author(s):  
D Pupo Gómez ◽  
V Reyes-Nicolas ◽  
G Marrero ◽  
N Perreault ◽  
A Menendez ◽  
...  
Keyword(s):  
Gene Expression ◽  
Salmonella Typhimurium ◽  
Intestinal Epithelium ◽  
Bacterial Infections ◽  
Mutant Mice ◽  
Epithelial Barrier ◽  
Epithelial Barrier Function ◽  
Efficacy Analysis ◽  
Salmonella Infections ◽  
The Impact

Abstract Background Inflammatory bowel diseases (IBD) are a group of chronic disorders that affect more than 233 000 Canadians and for which there is not yet an effective treatment. In addition, IBD is a multifactorial disease depending on genetic, immune and environmental dysregulations. The gastrointestinal epithelium plays an important role as a barrier that protects against antigens and bacterial products that are in the lumen. It is well recognized that a defect in the integrity of the barrier and its functions may be involved in the development of these diseases. On the other hand, our laboratory has shown that the conditional deletion of HNF4alpha nuclear receptor (Hnf4a) in the intestinal epithelium of mice can lead to the development of chronic inflammation of the intestine. However, the impact of the loss of this transcriptional factor on the epithelial barrier is still controversial. Aims To evaluate the impact of Hnf4a deletion on the epithelial barrier during bacterial infections. Methods We used a tamoxifen-inducible Cre-loxP system to delete the Hnf4a gene in the intestinal epithelium of 2-month-old mice, that were then infected with an attenuated strain of Salmonella typhimurium (SB1003) during 4 days. S. typhimurium loads were determined in cecum and colon content, and in liver, spleen tissues by plating homogenates on LB agar supplemented with streptomycin. Also, histological examinations and gene expression of selected targets were assessed between mutant (Hnf4aΔIEC) and control mice. Results The tamoxifen-inducible Cre-loxP system was able to delete intestinal Hnf4a gene expression with almost 100% of efficacy. Analysis by qPCR showed that the infection caused significant changes on the response of different infection responsive components (Relmβ, Muc2 and IL-33) in mutant mice. In addition, morphological analyses revealed an increase in the infiltration of immune cells and the number of goblets cells, indicative of an increase in the susceptibility to Salmonella typhimurium (SB1003) infection of the mutant mice. Conclusions Altogether, our results suggest that Hnf4a could be involved or play an important role as a modulator of the intestinal epithelial barrier function during Salmonella typhimurium (SB1003) infection. Therefore, understanding the mechanisms involved in this process could allow the development of better therapies for IBD. Funding Agencies CIHR

Stabilization but no functional influence of HIF-1α expression in the intestinal epithelium during Salmonella Typhimurium infection

2022 ◽  
Author(s):  
Laura Robrahn ◽  
Aline Dupont ◽  
Sandra Jumpertz ◽  
Kaiyi Zhang ◽  
Christian H. Holland ◽  
...  
Keyword(s):  
Gene Expression ◽  
Intestinal Epithelium ◽  
Bacterial Infections ◽  
Inflammatory Diseases ◽  
Protein Stabilization ◽  
Inflammatory Factors ◽  
Intestinal Epithelial ◽  
Data Set ◽  
The Impact

The hypoxia-inducible transcription factor 1 (HIF-1) has been shown to enhance microbial killing and to ameliorate the course of bacterial infections. While the impact of HIF-1 on inflammatory diseases of the gut has been studied intensively, its function in bacterial infections of the gastrointestinal tract remains largely elusive. With the help of a publicly available gene expression data set, we could infer significant activation of HIF-1 after oral infection of mice with Salmonella Typhimurium. Immunohistochemistry and western blot analysis confirmed marked HIF-1α protein stabilization, especially in the intestinal epithelium. This prompted us to analyze conditional Hif1a -deficient mice to examine cell type-specific functions of HIF-1 in this model. Our results demonstrate enhanced non-canonical induction of HIF-1 activity upon Salmonella infection in the intestinal epithelium as well as in macrophages. Surprisingly, Hif1a deletion in intestinal epithelial cells did not impact on inflammatory gene expression, bacterial spread or disease outcome. In contrast, Hif1a deletion in myeloid cells enhanced intestinal Cxcl2 expression and reduced the cecal Salmonella load. In vitro , HIF-1α-deficient macrophages showed an overall impaired transcription of mRNA encoding pro-inflammatory factors, however, intracellular survival of Salmonella was not impacted by HIF-1α deficiency.

scholarly journals PGC-1α mediates a metabolic host defense response in human airway epithelium during rhinovirus infections

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Aubrey N. Michi ◽  
Bryan G. Yipp ◽  
Antoine Dufour ◽  
Fernando Lopes ◽  
David Proud
Keyword(s):  
Host Defense ◽  
Barrier Function ◽  
Bacterial Infections ◽  
Molecular Mechanisms ◽  
Cellular Damage ◽  
Epithelial Barrier ◽  
Airway Epithelial ◽  
Barrier Dysfunction ◽  
Epithelial Barrier Function ◽  
Epithelial Damage

AbstractHuman rhinoviruses (HRV) are common cold viruses associated with exacerbations of lower airways diseases. Although viral induced epithelial damage mediates inflammation, the molecular mechanisms responsible for airway epithelial damage and dysfunction remain undefined. Using experimental HRV infection studies in highly differentiated human bronchial epithelial cells grown at air-liquid interface (ALI), we examine the links between viral host defense, cellular metabolism, and epithelial barrier function. We observe that early HRV-C15 infection induces a transitory barrier-protective metabolic state characterized by glycolysis that ultimately becomes exhausted as the infection progresses and leads to cellular damage. Pharmacological promotion of glycolysis induces ROS-dependent upregulation of the mitochondrial metabolic regulator, peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), thereby restoring epithelial barrier function, improving viral defense, and attenuating disease pathology. Therefore, PGC-1α regulates a metabolic pathway essential to host defense that can be therapeutically targeted to rescue airway epithelial barrier dysfunction and potentially prevent severe respiratory complications or secondary bacterial infections.

scholarly journals Behaviour of Human Oral Epithelial Cells Grown on Invisalign® SmartTrack® Material

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5311
Author(s):  
Michael Nemec ◽  
Hans Magnus Bartholomaeus ◽  
Michael H. Bertl ◽  
Christian Behm ◽  
Hassan Ali Shokoohi-Tabrizi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Epithelial Cells ◽  
Barrier Function ◽  
Inflammatory Markers ◽  
Cell Counting ◽  
Optical Cell ◽  
Epithelial Barrier Function ◽  
Oral Epithelial Cells ◽  
Oral Epithelial ◽  
The Impact

Invisalign aligners have been widely used to correct malocclusions, but their effect on oral cells is poorly known. Previous research evaluated the impact of aligners’ eluates on various cells, but the cell behavior in direct contact with aligners is not yet studied. In the present study, we seeded oral epithelial cells (cell line Ca9-22) directly on Invisalign SmartTrack material. This material is composed of polyurethane and co-polyester and exhibit better mechanical characteristics compared to the predecessor. Cell morphology and behavior were investigated by scanning electron microscopy and an optical cell moves analyzer. The effect of aligners on cell proliferation/viability was assessed by cell-counting kit (CCK)-8 and 3,4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide (MTT) assay and live/dead staining. The expression of inflammatory markers and proteins involved in epithelial barrier function was measured by qPCR. Cells formed cluster-like structures on aligners. The proliferation/viability of cells growing on aligners was significantly lower (p < 0.05) compared to those growing on tissue culture plastic (TCP). Live/dead staining revealed a rare occurrence of dead cells on aligners. The gene expression level of all inflammatory markers in cells grown on aligners’ surfaces was significantly increased (p < 0.05) compared to cells grown on TCP after two days. Gene expression levels of the proteins involved in barrier function significantly increased (p < 0.05) on aligners’ surfaces after two and seven days of culture. Aligners’ material exhibits no cytotoxic effect on oral epithelial cells, but alters their behavior and the expression of proteins involved in the inflammatory response, and barrier function. The clinical relevance of these effects has still to be established.

scholarly journals RNA-Seq Analysis of Differentiated Keratinocytes Reveals a Massive Response to Late Events during Human Papillomavirus 16 Infection, Including Loss of Epithelial Barrier Function

2017 ◽  
Vol 91 (24) ◽  
Author(s):  
T. Klymenko ◽  
Q. Gu ◽  
I. Herbert ◽  
A. Stevenson ◽  
V. Iliev ◽  
...  
Keyword(s):  
Gene Expression ◽  
Human Papillomavirus ◽  
Life Cycle ◽  
Cell Differentiation ◽  
Barrier Function ◽  
Hpv Infection ◽  
Epithelial Barrier ◽  
Rna Seq ◽  
Epithelial Barrier Function ◽  
Hpv16 Infection

ABSTRACT The human papillomavirus (HPV) replication cycle is tightly linked to epithelial cell differentiation. To examine HPV-associated changes in the keratinocyte transcriptome, RNAs isolated from undifferentiated and differentiated cell populations of normal, spontaneously immortalized keratinocytes (NIKS) and NIKS stably transfected with HPV16 episomal genomes (NIKS16) were compared using next-generation sequencing (RNA-Seq). HPV16 infection altered expression of 2,862 cellular genes. Next, to elucidate the role of keratinocyte gene expression in late events during the viral life cycle, RNA-Seq was carried out on triplicate differentiated populations of NIKS (uninfected) and NIKS16 (infected). Of the top 966 genes altered (>log2 = 1.8, 3.5-fold change), 670 genes were downregulated and 296 genes were upregulated. HPV downregulated many genes involved in epithelial barrier function, which involves structural resistance to the environment and immunity to infectious agents. For example, HPV infection repressed expression of the differentiated keratinocyte-specific pattern recognition receptor TLR7, the Langerhans cell chemoattractant CCL20, and proinflammatory cytokines interleukin 1α (IL-1α) and IL-1β. However, the type I interferon regulator IRF1, kappa interferon (IFN-κ), and viral restriction factors (IFIT1, -2, -3, and -5, OASL, CD74, and RTP4) were upregulated. HPV infection abrogated gene expression associated with the physical epithelial barrier, including keratinocyte cytoskeleton, intercellular junctions, and cell adhesion. Quantitative PCR (qRT-PCR) and Western blotting confirmed changes in expression of seven of the most significantly altered mRNAs. Expression of three genes showed statistically significant changes during cervical disease progression in clinical samples. Taken together, the data indicate that HPV infection manipulates the differentiating keratinocyte transcriptome to create an environment conducive to productive viral replication and egress. IMPORTANCE HPV genome amplification and capsid formation take place in differentiated keratinocytes. The viral life cycle is intimately associated with host cell differentiation. Deep sequencing (RNA-Seq) of RNA from undifferentiated and differentiated uninfected and HPV16-positive keratinocytes showed that almost 3,000 genes were differentially expressed in keratinocytes due to HPV16 infection. Strikingly, the epithelial barrier function of differentiated keratinocytes, comprising keratinocyte immune function and cellular structure, was found to be disrupted. These data provide new insights into the virus-host interaction that is crucial for the production of infectious virus and reveal that HPV infection remodels keratinocytes for completion of the virus replication cycle.

Decreased epithelial barrier function evoked by exposure to metabolic stress and nonpathogenic E. coli is enhanced by TNF-α

2008 ◽  
Vol 294 (3) ◽  
pp. G669-G678 ◽  
Author(s):  
Kimberley Lewis ◽  
Jackie Caldwell ◽  
Van Phan ◽  
David Prescott ◽  
Aisha Nazli ◽  
...  
Keyword(s):  
Cell Line ◽  
Barrier Function ◽  
Metabolic Stress ◽  
Epithelial Barrier ◽  
Pyrrolidine Dithiocarbamate ◽  
Epithelial Permeability ◽  
Epithelial Barrier Function ◽  
E Coli ◽  
Tnf Α ◽  
The Impact

A defect in mitochondrial activity contributes to many diseases. We have shown that monolayers of the human colonic T84 epithelial cell line exposed to dinitrophenol (DNP, uncouples oxidative phosphorylation) and nonpathogenic Escherichia coli ( E. coli) (strain HB101) display decreased barrier function. Here the impact of DNP on macrophage activity and the effect of TNF-α, DNP, and E. coli on epithelial permeability were assessed. DNP treatment of the human THP-1 macrophage cell line resulted in reduced ATP synthesis, and, although hyporesponsive to LPS, the metabolically stressed macrophages produced IL-1β, IL-6, and TNF-α. Given the role of TNF-α in inflammatory bowel disease (IBD) and the association between increased permeability and IBD, recombinant TNF-α (10 ng/ml) was added to the DNP (0.1 mM) + E. coli (106 colony-forming units), and this resulted in a significantly greater loss of T84 epithelial barrier function than that elicited by DNP + E. coli. This increased epithelial permeability was not due to epithelial death, and the enhanced E. coli translocation was reduced by pharmacological inhibitors of NF-κβ signaling (pyrrolidine dithiocarbamate, NF-κβ essential modifier-binding peptide, BAY 11–7082, and the proteosome inhibitor, MG132). In contrast, the drop in transepithelial electrical resistance was unaffected by the inhibitors of NF-κβ. Thus, as an integrative model system, our findings support the induction of a positive feedback loop that can severely impair epithelial barrier function and, as such, could contribute to existing inflammation or trigger relapses in IBD. Thus metabolically stressed epithelia display increased permeability in the presence of viable nonpathogenic E. coli that is exaggerated by TNF-α released by activated immune cells, such as macrophages, that retain this ability even if they themselves are experiencing a degree of metabolic stress.

scholarly journals A267 ROLE OF INTESTINAL EPITHELIAL NUCLEAR RECEPTOR HNF4A DURING METABOLIC DISORDERS

2020 ◽  
Vol 3 (Supplement_1) ◽  
pp. 144-145
Author(s):  
S Tremblay ◽  
R Girard ◽  
C Noll ◽  
A Carpentier ◽  
F Boudreau
Keyword(s):  
Glucose Metabolism ◽  
Nuclear Receptor ◽  
Intestinal Epithelium ◽  
Mutant Mice ◽  
Mouse Serum ◽  
Intestinal Epithelial ◽  
Metabolic Resistance ◽  
Brown Adipose ◽  
The Impact ◽  
Female Mutant

Abstract Background HNF4α belongs to the hormone nuclear receptor family and is expressed in liver, intestinal epithelium and pancreas where it regulates genes involved in the control of metabolism. Inactivating mutations in the HNF4A gene cause several forms of maturity-onset diabetes of the young (MODY). However, the specific deletion of Hnf4a in mouse pancreatic beta cells does not lead to diabetes, suggesting the contribution of other tissues, such as the intestine, are necessary for the progression of the disease. Aims Our main hypothesis was that intestinal epithelial HNF4α regulates gene products that act through a paracrine mode of communication in the context of glucose metabolism. The aims of this study were to investigate the impact of deleting Hnf4a in the mouse intestinal epithelium during glucose homeostasis and to identify molecular mechanisms involved during glucose-induced obesity resistance. Methods The Villin-Cre recombinase transgenic mouse model was used to conditionally delete Hnf4a in the intestinal epithelium (Hnf4adeltaIEC). Hnf4adeltaIEC mice were put on a high sugar diet for 8 to 12 weeks, using a 30% sucrose supplemented ab lithium water. Blood glucose values in controls and mutants were measured from whole venous blood from fasted mice or during glucose and insulin tolerance tests. Mouse serum hormone levels (Ghrelin, Fibroblast-growth factor-15 (Fgf15), Insulin, Cholecystokinin (CCK), etc.) were measured using mouse ELISA kits. The Promethion High-Definition Room Calorimetry System was used for indirect calorimetry and metabolic studies. Results Both male and female Hnf4adeltaIEC mice displayed a metabolic resistance to develop obesity under sucrose supplementation when compared to control mice. While male mutant mice showed a resistance to obesity after only 2 weeks of treatment, female mutant mice took at least 6 weeks to display some resistance. The gut hormones ghrelin and Fgf15 were also found modified in fasted mutant mice. Female mutant mice presented a significant increase of 1.8 fold in circulating Fgf15 and an increase of 1.4 fold in circulating ghrelin. Similar changes were observed in male mutant mice. However, only male mutant mice presented an insulin resistance and an oral glucose tolerance after between 6 and 8 weeks. Brown adipose tissue (BAT) whitening was observed after 8 weeks of sucrose treatment in control obese animals, a condition that was prevented in Hnf4adeltaIEC mice. Conclusions The identification of paracrine intestinal targets for HNF4α in association with glucose metabolism will provide a better understanding of the molecular nature of tissues crosstalk in energy balance and in metabolism disorders including diabetes and obesity. Funding Agencies CIHR

scholarly journals The impact of lactoferrin with different levels of metal saturation on the intestinal epithelial barrier function and mucosal inflammation

BioMetals ◽  
2016 ◽  
Vol 29 (6) ◽  
pp. 1019-1033 ◽  
Author(s):  
Grzegorz Majka ◽  
Grażyna Więcek ◽  
Małgorzata Śróttek ◽  
Klaudyna Śpiewak ◽  
Małgorzata Brindell ◽  
...  
Keyword(s):  
Barrier Function ◽  
Mucosal Inflammation ◽  
Epithelial Barrier ◽  
Intestinal Epithelial ◽  
Intestinal Epithelial Barrier ◽  
Epithelial Barrier Function ◽  
The Impact ◽  
Different Levels

scholarly journals When Insult Is Added to Injury: Cross Talk between ILCs and Intestinal Epithelium in IBD

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Esmé van der Gracht ◽  
Sonja Zahner ◽  
Mitchell Kronenberg
Keyword(s):  
Intestinal Epithelium ◽  
Immune Cells ◽  
Intestinal Barrier ◽  
Biochemical Properties ◽  
The Body ◽  
Lymphoid Cells ◽  
Intestinal Lumen ◽  
Epithelial Barrier ◽  
Epithelial Barrier Function ◽  
Critical Feedback

Inflammatory bowel disease (IBD) is characterized by an impairment of the integrity of the mucosal epithelial barrier, which causes exacerbated inflammation of the intestine. The intestinal barrier is formed by different specialized epithelial cells, which separate the intestinal lumen from the lamina propria. In addition to its crucial role in protecting the body from invading pathogens, the intestinal epithelium contributes to intestinal homeostasis by its biochemical properties and communication to underlying immune cells. Innate lymphoid cells (ILCs) are a recently described population of lymphocytes that have been implicated in both mucosal homeostasis and inflammation. Recent findings indicate a critical feedback loop in which damaged epithelium activates these innate immune cells to restore epithelial barrier function. This review will focus on the signalling pathways between damaged epithelium and ILCs involved in repair of the epithelial barrier and tissue homeostasis and the relationship of these processes with the control of IBD.

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