scholarly journals Yersinia pseudotuberculosis YopE prevents uptake by M cells and instigates M cell extrusion in human ileal enteroid-derived monolayers.

2021 ◽  
Author(s):  
Alyssa C Fasciano ◽  
Gaya S Dasanayake ◽  
Mary K Estes ◽  
Nicholas C Zachos ◽  
David T Breault ◽  
...  
Keyword(s):  
Yersinia Pseudotuberculosis ◽  
Cell Function ◽  
Cell Types ◽  
Microbial Pathogens ◽  
Intestinal Cell ◽  
M Cells ◽  
M Cell ◽  
T3ss Effector ◽  
Type Three Secretion System ◽  
Infectious Stage

Many pathogens use M cells to access the underlying Peyers patches and spread to systemic sites via the lymph as demonstrated by ligated loop murine intestinal models. However, the study of interactions between M cells and microbial pathogens has stalled due to the lack of cell culture systems. To overcome this obstacle, we use human ileal enteroid-derived monolayers containing five intestinal cell types including M cells to study the interactions between the enteric pathogen, Yersinia pseudotuberculosis (Yptb) and M cells. The Yptb type three secretion system (T3SS) effector Yops inhibit host defenses including phagocytosis and are critical for colonization of the intestine and Peyers patches. Therefore, it is not understood how Yptb traverses through M cells to breach the epithelium. By growing Yptb under two physiological conditions that mimic the early infectious stage (low T3SS-expression) or host-adapted stage (high T3SS-expression), we found that large numbers of Yptb specifically associated with M cells, recapitulating murine studies. Transcytosis through M cells was significantly higher by Yptb expressing low levels of T3SS, because YopE and YopH prevented Yptb uptake. YopE also caused M cells to extrude from the epithelium without inducing cell-death or disrupting monolayer integrity. Sequential infection with early infectious stage Yptb reduced host-adapted Yptb association with M cells. These data underscore the strength of enteroids as a model by discovering that Yops impede M cell function, indicating that early infectious stage Yptb more effectively penetrates M cells while the host may defend against M cell penetration of host-adapted Yptb.

scholarly journals Human Intestinal M Cells Display the Sialyl Lewis A Antigen

1999 ◽  
Vol 67 (2) ◽  
pp. 946-953 ◽  
Author(s):  
Paul J. Giannasca ◽  
Karen T. Giannasca ◽  
Alan M. Leichtner ◽  
Marian R. Neutra
Keyword(s):  
Cell Types ◽  
M Cells ◽  
Intestinal Epithelial ◽  
M Cell ◽  
Sialyl Lewis ◽  
Normal Individuals ◽  
Sialyl Lewis A ◽  
Inflammatory Bowel ◽  
Small Subpopulation ◽  
Lewis A

ABSTRACT The biochemical features that distinguish human M cells from other intestinal epithelial cell types are important for understanding microbial pathogenesis and for targeting vaccines to the mucosal immune system. We applied a large panel of carbohydrate-specific monoclonal antibodies and lectins to Peyer’s patch and cecum biopsy specimens from three normal individuals and a patient with inflammatory bowel disease. The results show that human M-cell glycosylation patterns are distinct from those of other species examined and that human M cells preferentially display the sialyl Lewis A antigen. This carbohydrate epitope is also present in a small subpopulation of enterocytes in the follicle-associated epithelium and in goblet cell mucins.

scholarly journals Do M-cells contribute significantly in T-wave morphology during normal and arrhythmogenesis conditions like short QT Syndrome?

2020 ◽  
Author(s):  
Ponnuraj Kirthi Priya ◽  
Srinivasan Jayaraman
Keyword(s):  
Cell Types ◽  
M Cells ◽  
Short Qt Syndrome ◽  
M Cell ◽  
T Wave ◽  
Wave Morphology ◽  
Qt Syndrome ◽  
Premature Beats ◽  
Low Amplitude ◽  
T Waves

AbstractAimsThis paper proposes to explain the mechanism of M-cells, particularly its role in the T-wave generation and its contribution to arrhythmogenesis in short QT syndrome 2 (SQTS2).MethodsA 2D transmural anisotropic ventricular model made up of three principal cell types were developed. Different setups in which: a) entire column of mid-myocardial (mid) cells, b) single island of cells c) two island of cells within the mid-layer d) single island of cells in endocardial (endo)-mid layer were considered as M-cells. These setups are stimulated to explain i) contribution of M-cells in T-wave morphology ii) arrhythmia generation phenomena under SQTS2 heterozygous gene mutation by creating pseudo ECGs from the tissue.ResultsFindings infer that setups with an entire layer of M-cells and a higher percentage of epicardial (epi) cells exhibit positive T-waves. Increasing the size of the island in M-cell island setups results in an increased positive T-peak. Placing the M-cell island in the bottom of the mid-layer produced low amplitude T-waves. Further, in two M-cell islands setup, a higher T-wave amplitude was observed when the islands are placed closer than far apart. Moving the M-cell island slightly into the endo layer increases the amplitude of the T-wave. Lastly, on including SQTS2 conditions and pacing with premature beats, an arrhythmia occurs only in those setups containing a layer of M-cells compared to M-cells island setup.ConclusionThese simulation findings paved the way for a better understanding of the M-cells functionality in T-wave morphology as well as promoting arrhythmogenesis under SQTS2 condition.

scholarly journals M-Cell Surface β1 Integrin Expression and Invasin-Mediated Targeting of Yersinia pseudotuberculosis to Mouse Peyer’s Patch M Cells

1998 ◽  
Vol 66 (3) ◽  
pp. 1237-1243 ◽  
Author(s):  
M. Ann Clark ◽  
Barry H. Hirst ◽  
Mark A. Jepson
Keyword(s):  
Cell Surface ◽  
Yersinia Pseudotuberculosis ◽  
M Cells ◽  
Β1 Integrin ◽  
Integrin Expression ◽  
Peyer’S Patch ◽  
Peyer's Patch ◽  
M Cell ◽  
Apical Membranes

ABSTRACT Quantitative analysis of Yersinia pseudotuberculosisinfection of murine gut loops revealed that significantly more wild-type bacteria associated with Peyer’s patch M cells than with dome enterocytes or goblet cells. An invasin-deficient mutant was significantly attenuated for M-cell invasion, while β1 integrin expression was demonstrated in the apical membranes of M cells but not enterocytes. M-cell targeting by Yersinia pseudotuberculosis in vivo may, therefore, be mediated primarily by the interaction of invasin with cell surface β1 integrins.

scholarly journals M-cells in the rabbit tonsil exhibit distinctive glycoconjugates in their apical membranes.

1996 ◽  
Vol 44 (9) ◽  
pp. 1033-1042 ◽  
Author(s):  
A Gebert
Keyword(s):  
Epithelial Cells ◽  
Immune Responses ◽  
Cell Types ◽  
Lectin Histochemistry ◽  
Lymphoid Cells ◽  
M Cells ◽  
M Cell ◽  
Double Labeling ◽  
Specific Composition ◽  
Apical Membranes

The tonsil crypt epithelium contains membranous (M)-cells that transport antigens from the lumen to underlying lymphoid cells, thereby initiating specific immune responses. Mechanisms mediating the adhesion of antigens to the M-cell surface are important for effective and selective uptake of potential pathogens but are still poorly understood. Therefore, the carbohydrates present on crypt epithelial cells of the rabbit palatine tonsil were studied by lectin histochemistry. Ultrathin LR White sections were incubated with a panel of eight lectins conjugated to colloidal gold or biotin. The glycocalyx of the apical membrane of M-cells was selectively labeled by UEA-I, LTA, HPA, and VVA, whereas that of the remaining squamous epithelial cells preferentially bound RCA-I and PNA. WGA and ConA showed only little binding, with no discernible preference for any of the cell types. Double labeling of UEA-1 together with anti-vimentin antibodies revealed that UEA-I-positive epithelial cells also contained the rabbit M-cell marker vimentin, and vice versa. The results show that a specific composition of glycoconjugates, which differs from that on squamous epithelial cells, is found on M-cells of the rabbit tonsil. The M-cell-specific glycoproteins and glycolipids could be selectively targeted by microorganisms that adhere to M-cells and enter the host along this pathway.

scholarly journals Microbial Pattern Recognition Receptors Mediate M-Cell Uptake of a Gram-Negative Bacterium

2006 ◽  
Vol 74 (1) ◽  
pp. 625-631 ◽  
Author(s):  
Peter Tyrer ◽  
A. Ruth Foxwell ◽  
Allan W. Cripps ◽  
Michael A. Apicella ◽  
Jennelle M. Kyd
Keyword(s):  
Pattern Recognition ◽  
Cell Types ◽  
Pattern Recognition Receptors ◽  
M Cells ◽  
M Cell ◽  
Gram Negative ◽  
Bacterial Uptake ◽  
Α5β1 Integrin

ABSTRACT The receptors involved in the sampling of particulate microbial antigens by the gut are largely unknown. Here we demonstrate for the first time in an in vitro M-cell model and in situ in isolated murine intestinal segments that the receptors TLR-4, PAF-R, and α5β1 integrin are all involved in mediating bacterial uptake associated with transcytosis. The pattern of expression of TLR-4 and α5β1 integrin differed between M cells and enterocytes. There was increased apical expression of TLR-4 in M-cell cultures, and it was present on the apical surface of murine M cells but not enterocytes in situ. In contrast, PAF-R was expressed equally by both cell types in vitro and was abundantly expressed throughout the intestinal epithelium. Inhibition of TLR-4 and PAF-R, but not TLR-2, reduced gram-negative bacterial uptake by both cell types, whereas inhibition of the apically expressed α5β1 integrin significantly reduced the ability of M cells to translocate bacteria. Hence, the involvement of each receptor was dependent not only on differences in the level of receptor expression but the cellular localization. Using bacteria that had mutations that affected the bacterial lipooligosaccharide structure indicated that the oligosaccharide moiety was important in bacterial uptake. Taken together, the data suggest that pathogen-associated molecular pattern interactions with pattern recognition receptors are key factors in M-cell recognition of intestinal antigens for mucosal immune priming.

scholarly journals Yersinia pseudotuberculosis YopE prevents uptake by M cells and instigates M cell extrusion in human ileal enteroid-derived monolayers

Gut Microbes ◽  
2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Alyssa C. Fasciano ◽  
Gaya S. Dasanayake ◽  
Mary K. Estes ◽  
Nicholas C. Zachos ◽  
David T. Breault ◽  
...  
Keyword(s):  
Yersinia Pseudotuberculosis ◽  
M Cells ◽  
M Cell ◽  
Cell Extrusion

scholarly journals Coronin-1 is necessary for enteric pathogen-induced transcytosis across human ileal enteroid monolayers expressing M cells

2020 ◽  
Author(s):  
Janet F. Staab ◽  
Michele Doucet ◽  
Rachel Latanich ◽  
Sun Lee ◽  
Mary K. Estes ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Cell Function ◽  
Enteric Pathogens ◽  
Cell Uptake ◽  
Human Model ◽  
M Cells ◽  
M Cell ◽  
E Coli ◽  
Entry Pathway ◽  
Healthy Donors

ABSTRACTIn the intestine, luminal sampling by microfold (M) cells is crucial for inducing protective mucosal immune responses but can also serve as an entry pathway for pathogens, including bacteria and viruses. Enteric pathogens can influence intestinal M cell function; however, the molecular mechanisms involved in the regulation of uptake and transcytosis of gut cargo by human M cells remain to be determined. Understanding the mechanisms responsible for regulating human M cell function requires a relevant human model. In this study, human ileal enteroids established from healthy donors were grown as confluent monolayers on permeable supports and differentiated to express mature M cells. Enteric pathogens including enteropathogenic E. coli (EPEC), adherent invasive E. coli (AIEC), and human rotavirus were apically exposed to M cell enteroid monolayers. M cell-mediated uptake and transcytosis was compared in enteroids infected by pathogenic or commensal bacteria (HS strain). EPEC and AIEC, but not HS, stimulated M cell uptake and transcytosis. We discovered that this pathogenspecific effect was dependent on expression of coronin 1a, a cytoskeletal remodeling protein. Using stable coronin 1a knockdown (KD) enteroids, we observed that EPEC-stimulated transcytosis of fluorescent beads was lost and associated with a significant decrease in the number of glycoprotein-2 positive (Gp-2+ve) M cells. The results of these studies demonstrate that coronin 1a is required for uptake and transcytosis of luminal cargo across human M cells and that coronin 1a is necessary for differentiation of mature M cells that actively transcytose luminal gut antigens in response to pathogenic, but not commensal, microbes.

Freeze-substitution of rye grass and ragweed pollen grains

1990 ◽  
Vol 48 (3) ◽  
pp. 686-687
Author(s):  
Liza B. Martinez ◽  
Susan M. Wick
Keyword(s):  
Cell Function ◽  
Pollen Grains ◽  
Freeze Substitution ◽  
Cell Types ◽  
Rapid Freezing ◽  
Rye Grass ◽  
Acrylic Resins ◽  
Allergenic Proteins ◽  
Cold Embedding ◽  
Structural Preservation

Rapid freezing and freeze-substitution have been employed as alternatives to chemical fixation because of the improved structural preservation obtained in various cell types. This has been attributed to biomolecular immobilization derived from the extremely rapid arrest of cell function. These methods allow the elimination of conventionally used fixatives, which may have denaturing or “masking” effects on proteins. Thus, this makes them ideal techniques for immunocytochemistry, in which preservation of both ultrastructure and antigenicity are important. These procedures are also compatible with cold embedding acrylic resins which are known to increase sensitivity in immunolabelling.This study reveals how rapid freezing and freeze-substitution may prove to be useful in the study of the mobile allergenic proteins of rye grass and ragweed. Most studies have relied on the use of osmium tetroxide to achieve the necessary ultrastructural detail in pollen whereas those that omitted it have had to contend with poor overall preservation.

scholarly journals Multiple Roles for Cholinergic Signaling from the Perspective of Stem Cell Function

2021 ◽  
Vol 22 (2) ◽  
pp. 666
Author(s):  
Toshio Takahashi
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Function ◽  
Cell Activity ◽  
Embryonic Stem ◽  
Cholinergic Neurons ◽  
Cell Types ◽  
Proliferative Potential ◽  
True Nature ◽  
Cholinergic Signaling

Stem cells have extensive proliferative potential and the ability to differentiate into one or more mature cell types. The mechanisms by which stem cells accomplish self-renewal provide fundamental insight into the origin and design of multicellular organisms. These pathways allow the repair of damage and extend organismal life beyond that of component cells, and they probably preceded the evolution of complex metazoans. Understanding the true nature of stem cells can only come from discovering how they are regulated. The concept that stem cells are controlled by particular microenvironments, also known as niches, has been widely accepted. Technical advances now allow characterization of the zones that maintain and control stem cell activity in several organs, including the brain, skin, and gut. Cholinergic neurons release acetylcholine (ACh) that mediates chemical transmission via ACh receptors such as nicotinic and muscarinic receptors. Although the cholinergic system is composed of organized nerve cells, the system is also involved in mammalian non-neuronal cells, including stem cells, embryonic stem cells, epithelial cells, and endothelial cells. Thus, cholinergic signaling plays a pivotal role in controlling their behaviors. Studies regarding this signal are beginning to unify our understanding of stem cell regulation at the cellular and molecular levels, and they are expected to advance efforts to control stem cells therapeutically. The present article reviews recent findings about cholinergic signaling that is essential to control stem cell function in a cholinergic niche.

LOSS OF GLUTATHIONE PEROXIDASE 1 ATTENUATES COLITIS AND IS CRITICAL IN ACTIVATING EPITHELIAL REGENERATIVE RESPONSES

2021 ◽  
Vol 27 (Supplement_1) ◽  
pp. S27-S27
Author(s):  
Jared Hendren ◽  
Koral Kasnyik ◽  
Christopher Williams ◽  
Sarah Short
Keyword(s):  
Stem Cell ◽  
Glutathione Peroxidase ◽  
Target Genes ◽  
Cell Function ◽  
Intestinal Inflammation ◽  
Cellular Metabolism ◽  
Intestinal Injury ◽  
Gene Set Enrichment Analysis ◽  
Intestinal Cell ◽  
Glutathione Peroxidase 1

Abstract Many selenium-containing “selenoproteins” function as antioxidants, and work by our lab and others has demonstrated that selenoproteins often protect against intestinal inflammatory diseases, including colitis. Glutathione peroxidase 1 (GPx1) is a ubiquitous, mitochondrial and cytosolic selenoprotein which catalyzes the reduction of hydrogen peroxide by glutathione. Previously, we determined that despite its antioxidant role, loss of GPx1 greatly reduced disease severity in the dextran sodium sulfate (DSS) colitis model. Furthermore, GPx1 loss increased baseline intestinal cell proliferation, enhanced enteroid plating efficiency, and induced expression of stem cell-associated genes, such as Lgr5. Next, we aimed to determine the mechanism by which GPx1 modifies response to DSS. We observed that GPx1 is increased in colonic tissues from DSS-treated mice as compared to nontreated controls, suggesting that GPx1 may functionally contribute to intestinal injury responses. While GPx1 is expressed in both intestinal epithelial and immune cells, in situ hybridization to visualize Gpx1 identified epithelial cells as the most highly expressing cell type, with the greatest Gpx1 upregulation observed in wound-adjacent and regenerative crypts. Next, we investigated whether GPx1 loss affects stem cell function after injury. Here, we determined that both proliferation (p<0.01) and Lgr5 expression (p<0.05) were increased in the crypts of Gpx1-/- DSS-treated mice in comparison to WT controls. Similarly, organoids established from ulcerative colitis tissue displayed increased growth rates (p<0.01), expression of stem cell and Wnt target genes such as AXIN2 (p<0.0001) and LGR5 (p<0.01), and proliferation (p<0.05) following GPX1 knockdown. Together, these results indicate that GPx1 has an epithelial-cell autonomous role, and that its loss activates stem cell and proliferative responses which may both protect from intestinal injury and promote healing. Interestingly, recent research has highlighted the role of cellular metabolism in maintaining intestinal stem cell function, and GPx1 has previously been implicated in these processes. RNA-sequencing from DSS-treated mice and gene set enrichment analysis identified a positive association with oxidative phosphorylation-associated genes in Gpx1-/- mice (NES: 1.78; FDR q-val: 0.01), suggesting altered metabolism which may favor stem cell function. Further analysis of cellular metabolism using GPX1 knockdown colorectal cancer cells observed higher basal respiration (p<0.0001) and ATP generation (p<0.0001). Together, these results suggest that unlike other intestinal selenoproteins studied to date, loss of GPx1 augments stem cell injury responses to protect against intestinal inflammation, likely via augmenting epithelial regenerative responses.

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