197,573 research outputs found
M cells and the FAE
No full textTranscriptomic data base on gene expression by mouse M cells Identification of Novel Genes Selectively Expressed in the Follicle-Associated Epithelium from the Meta-Analysis of Transcriptomics Data from Multiple Mouse Cell and Tissue PopulationsThe follicle-associated epithelium (FAE) overlying the Peyer’s patches and the microfold (M) cells within it are important sites of antigen transcytosis across the intestinal epithelium. We obtained a large number of gene expression data files from a range of different primary mouse cells and cell lines and subjected these data to network-based cluster analysis using Biolayout Express3D. Using this meta-analysis approach we identified a transcriptional signature that distinguished the FAE from a large collection of mouse cells and tissues. A co-expressed cluster of 21 FAE-specific genes was identified, and analysis of the transcription factor binding site motifs in their promoter regions indicated that these genes shared an underlying transcriptional programme. This cluster contained known FAE- (Anxa10, Ccl20, Psg18 and Ubd) and M-cell- (Gp2) specific genes, suggesting that the others were novel FAE-specific genes. Some of these novel candidate genes were expressed highly by the FAE and M cells (Calcb, Ces3b, Clca2 and Gjb2), and others only by the FAE (Ascl2, Cftr, Fgf15, Gpr133, Kcna1, Kcnj15, Mycl1, Pgap1 and Rps6kl). We also identified a subset of novel FAE-related genes that were induced in the intestinal epithelium after receptor activator of NF-κB ligand (RANKL)-stimulation. These included Mfge8 which was specific to FAE enterocytes. This study provides new insight into the FAE transcriptome. Further characterisation of the candidate genes identified here will aid the identification of novel regulators of cell function in the FAE
Zonation of M cells in the FAE.
No full textRelated to Fig 1 (A) Violin plots for the max-normalized expression of M cell signature genes (Methods) showing an up-regulation expression of M cell genes in FAET compared to FAEB and VB. (B) Violin plot showing up-regulation of Anxa5 expression in FAET compared to FAEB and VB. Five FAE zones from 2 mice. In A, B, white dots are median values; gray boxes delineate the 25–75 percentiles, p-values computed using Kruskal–Wallis tests. P > 0.05 for Anxa5 (B). (C) A smFISH image showing Anxa5 expression in the FAET. White dashed lines delimit FAET and FAEB areas, and red arrows mark cells with higher expression levels of Anxa5. Scale bar: 50 μm. The data used to generate this figure can be found in Supporting information S2 and S6 Data. FAE, follicle-associated epithelium; FAEB, FAE bottom; FAET, FAE top; smFISH, single-molecule fluorescence in situ hybridization; UMI, unique molecular identifier; VB, villus bottom. (TIF)</p
FAE miRNAs involved in M cell maturation.
No full text(A) Flowchart of M cell maturation. (B) Q-PCR analysis was performed for Marcksl1, SpiB, Ccl9 and Gp2 mRNA expression in DicerΔIEC FAE and DicerF/F FAE. The relative expression levels of each gene to Gapdh are shown. Values represent the mean ± SD of three samples from different mice. *P P < 0.01.</p
M cell: the main entrance of the mucosal immune system
No full textM cells are higly specialized cells within the follicle-associated epithelium (FAE) of the respiratory and intestinal tracts. They play a central role in the induction of the mucosal immune response by transporting antigens to the lymphoid tissue. In this way the immune system may encounter the limitless variety of antigens that enter the body through the gut and airways. Here we describe the structure and the function of intestinal M cells. In addition, controversial issues relating to the M cell biology, such as APC function and the origin of M cells within the FAE, are discussed
Caspase activation and photosensitizing effect of FAE.
No full text<p>(<b>A</b>) MCF-7 cells expressing Caspase FRET probes were exposed to 100 µg/ml of FAE for 24 h and 48 h. The ECFP, EYFP-FRET channels and merged images for DMSO treated and FAE treated cells are shown. The ECFP/EYFP ratio image is also shown. The graph shown is the quantitative ratio change in DMSO and FAE treated dying cells as analysed in NIS elements software (n = 4). (<b>B</b>) The same cells were stained with TMRM and exposed to 100 µg/ml of FAE and imaged for TMRM, ECFP, EYFP-FRET in a time lapse mode at an interval of 5 mins as described. The merged image of TMRM, ECFP, EYFP-FRET from the time lapse images for the indicated time points are shown. The ECFP/EYFP ratio change in DMSO and FAE treated cells is shown as graph. The graph indicates the quantitative ratio change in DMSO and FAE-treated dying cells (Complete frame is shown as <b><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040055#pone.0040055.s001" target="_blank">Video S1</a></b>). (<b>C</b>) The FRET expressing cells were treated as above and the imaging was carried out as described with an interval of 2 mins. A representative image for the indicated time is shown (Complete frame is shown as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040055#pone.0040055.s002" target="_blank">V<b>ideo S2</b></a>). (<b>D</b>) The same cells treated with DMSO and imaged as described for C. A representative image for the indicated time is shown (Complete frame is shown as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040055#pone.0040055.s003" target="_blank">V<b>ideo S3</b></a>).</p
Effect of FAE in regulating Bax translocation.
No full text<p>(<b>A</b>) MCF-7 cells expressing Bax EGFP and Mito DsRed were seeded in 96 well glass bottom plate (BD, USA) with low density and after 48 h, treated with FAE at 100 µg/ml. The image was taken using BD Pathway Bioimager 435 (Becton Dickinson, USA) at 3, 18 and 27 h by setting Montage (2×2) and specific Macro using AttoVision™ software. The green granular aggregate indicates the translocation of Bax to mitochondria, as indicated by the arrows. The representative images collected at indicated time points were used for analysing the percentage positive cells with Bax EGFP onto mitochondria compared to total in the field. (<b>B</b>) Graph showing the percentage of cells undergoing Bax translocation into mitochondria upon FAE treatment. (<b>C</b>) The MCF-Bax-DS Red cells were treated as indicated above. Bax-EGFP accumulation in mitochondria is indicated in high magnification images with arrows. A magnified merged image of the treated cells is also shown. (<b>D</b>) MCF-7 cells were transfected with Control (scr) siRNA or Bax siRNA. After 48 h of transfection, whole cell extract was prepared and immunoblotted for Bax and Actin. The same cells were also stained with Hoechst 33342 after 48 h of FAE treatment to visualize chromatin condensation (left panel). The graph is the quantitative representation of the percentage of cells with condensed chromatin in scrambled-transfected and Bax-transfected cells after FAE treatment.</p
IgA<sup>+</sup> cells in the FAE of mouse Peyer’s patches.
No full text<p>Cryosections of BALB/c Peyer’s patches were stained with antibodies directed against IgA (red, panels A, B; green, panels C, D), E-cadherin (green, Panel A, B) or the lectin UEA-1 (magenta, panels C,D), and then visualized by CLSM. (<b>A, B</b>) IgA+ cells are distributed within LP (arrows) and in FAE (arrowheads). The dashed box in Panel A is magnified in panel B. <b>(C, D)</b> In the FAE, IgA + cells are associated with UEA-1 positive cells, indicting that they are likely M cells. The dashed box in Panel C is magnified in panel D. Abbreviations: SED, subepithelial dome; FAE, follicle-associated epithelium.</p
Proposed signalling pathway for FAE induced apoptosis.
No full text<p>FAE induced conformational change in Bax through intracellular generation of ROS and triggered mitochondria mediated apoptosis involving loss of mitochondrial membrane potential. The release of mitochondrial Cytochrome c, which functions as an electron carrier in the respiratory chain, translocated to the cytosol, where it participated in the activation of Caspase 9 and 7, leading to apoptotic events in the cells. FAE also induced cell cycle arrest in G<sub>1</sub> phase, and photosensitization, but the exact mechanism by which this is brought about has to be investigated.</p
Formaldehyde activating enzyme (Fae) and hexulose-6-phosphate synthase (Hps) in Methanosarcina barkeri: a possible function in ribose-5-phosphate biosynthesis
No full textFormaldehyde activating enzyme (Fae) was first discovered in methylotrophic bacteria, where it is involved in the oxidation of methanol to CO2 and in formaldehyde detoxification. The 18 kDa protein catalyzes the condensation of formaldehyde with tetrahydromethanopterin (H4MPT) to methylene-H4MPT. We describe here that Fae is also present and functional in the methanogenic archaeon Methanosarcina barkeri. The faeA homologue in the genome of M. barkeri was heterologously expressed in Escherichia coli and the overproduced purified protein shown to actively catalyze the condensation reaction: apparent V-max = 13 U/mg protein (1 U = mu mol/min); apparent Km for H4MPT = 30 mu M; apparent Km for formaldehyde = 0.1 mM. By Western blot analysis the concentration of Fae in cell extracts of M. barkeri was determined to be in the order of 0.1% of the soluble cell proteins. Besides the faeA gene the genome of M. barkeri harbors a second gene, faeB-hpsB, which is shown to code for a 42 kDa protein with both Fae activity (3.6 U/mg) and hexulose-6-phosphate synthase (Hps) activity (4.4 U/mg). The results support the recent proposal that in methanogenic archaea Fae and Hps could have a function in ribose phosphate synthesis
Effect of FAE on expression of apoptosis related proteins and ROS generation.
No full text<p>(<b>A</b>) MCF-7 cells were treated with FAE (80, 160 µg/ml) for 48 h and harvested. Immunoblots were performed in whole cell extract using the indicated antibodies. The corresponding full-length and cleaved fragments are indicated. For PARP blot, cells were treated with 160 µg/ml of FAE for 48 h. (<b>B</b>) MCF-7 and T47D cells were treated with 100 µg/ml of FAE for 24 h. FAE induced ROS generation in MCF-7 as well as T47D cells than the DMSO control as indicated by increase in DCF-DA fluorescence in treated cells. (<b>C</b>) MCF-7 and T47D cells were treated with 100 µg/ml of FAE alone and after pre-treatment with NAC for a period of 24 h. As shown, pre-treatment of cells with the antioxidant NAC reduced the cell death induced by FAE. Percentage of cells with condensed chromatin for each group is shown as graph (N = 3).</p
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