Media from macrophages co-incubated with Enterococcus faecalis induces epithelial cell monolayer reassembly and altered cell morphology (original) (raw)
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Monocyte differentiation in intestine-like macrophage phenotype induced by epithelial cells
Journal of leukocyte biology, 2001
Macrophages in normal colonic mucosa show a specific and distinct phenotype with low expression of the typical monocyte/macrophage surface antigens CD14, CD16, and CD11b and T-cell costimulatory molecules. A method for the in vitro induction of a macrophage phenotype similar to this intestinal phenotype is presented. Multicellular spheroids (MCSs) of intestinal epithelial cell (IEC) and control cell lines were cocultured with elutriated monocytes. Surface antigen expression was analyzed by immunohistochemistry and flow cytometry. Interleukin (IL)-1beta mRNA was measured by quantitative PCR. Monocytes adhered and infiltrated the MCSs within 24 h. In the MCSs of all IEC lines, the typical monocyte/macrophage surface antigens CD14, CD16, CD11b, and CD11c, which are detectable after 24 h of coculture by immunohistochemistry and flow cytometry, were down-regulated after 7 days (e.g., for CD14 at 24 h, expression was 86% of CD33+ cells; at day 7, it was 11%). A clear decrease of lipopolys...
Translational Oncology, 2013
Intestinal commensal bacteria have recently been shown to trigger macrophages to produce diffusible clastogens (or chromosome-breaking factors) through a bystander effect (BSE) that mediates DNA damage and induces chromosomal instability in neighboring cells. Colon macrophages appear central to colon carcinogenesis and BSE through the expression of tumor necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2). The former induces netrin-1, a regulator of intestinal epithelial cell apoptosis, and the latter generates trans-4-hydroxy-2-nonenal (4-HNE), an endogenous mutagen. To test whether colon macrophages are key effectors for BSE, we depleted these cells in interleukin-10 knockout mice colonized with Enterococcus faecalis using encapsulated liposomal clodronate (ELC), a bisphosphonate that causes macrophage apoptosis. We observed that E. faecalis polarizes colon macrophages to an M1 phenotype. In addition, depleting these cells suppressed COX-2 and TNF-α, blocked the formation of 4-HNE protein adducts, and inhibited up-regulation of netrin-1-all markers for BSE. Finally, treatment with ELC prevented colitis, β-catenin activation, and cancer formation. These results show that selected human commensals can polarize colon macrophages to the M1 phenotype and, when activated, serve as the key effector for bacterial-induced BSE. Our findings suggest that depleting M1-polarized macrophages is a mechanism for the chemopreventive activity of bisphosphonates and that it represents a new strategy for preventing colon cancer induced by intestinal commensals.
Intestinal Macrophages and Intestinal Infection
Biosciences Biotechnology Research Asia, 2021
There has been increased interest in the role played by macrophages in the maintenance of an active immune system and intestinal homeostasis. Nonetheless, they are also responsible for the rise of chronic pathologies such as inflammatory bowel syndrome in the gut. The lack of differentiation of monocytes in the intestines due to disease conditions leads to a fall in the diversity of microbiota and subsequent gut inflammation. Macrophages play a central role in the homeostasis and immunity of the gut, making them potential sources of novel therapies or remedies for inflammatory bowel disease (IBD) patients. To explore this possibility, this research discusses their structure, differentiation, and functionality in an in-depth manner. It will also describe their role in the local intestinal environment and how it changes upon infection. Finally, the paper will outline its conclusions as well as comment on the future outlook of related research.
The ISME journal, 2015
We investigated the effects of early colonizing bacteria on the colonic epithelium. We isolated dominant bacteria, Escherichia coli, Enterococcus faecalis, Lactobacillus intestinalis, Clostridium innocuum and a novel Fusobacterium spp., from the intestinal contents of conventional suckling rats and transferred them in different combinations into germfree (GF) adult rats. Animals were investigated after various times up to 21 days. Proliferative cell markers (Ki67, proliferating cell nuclear antigen, phospho-histone H3, cyclin A) were higher in rats monocolonized with E. coli than in GF at all time points, but not in rats monocolonized with E. faecalis. The mucin content of goblet cells declined shortly after E. coli administration whereas the mucus layer doubled in thickness. Fluorescence in situ hybridization analyses revealed that E. coli resides in this mucus layer. The epithelial mucin content progressively returned to baseline, following an increase in KLF4 and in the cell cycl...
Crosstalk between epithelial cells and macrophages in the gut: the role of TNFR2
Kristek Maja Crosstalk Between Epithelial Cells and Macrophages in the Gut the Role of Tnfr2 Phd Thesis Dublin City University, 2014
Crosstalk between epithelial cells and macrophages in the gut: the role of TNFR2-Maja Kristek In order to cope with the overwhelming amount of commensal bacteria, dietary and environmental antigens, homeostasis in the intestine relies upon the fine tuned crosstalk between the immune cells and their environment. One of the key regulators of homeostasis in the intestine are macrophages. Unlike other macrophage populations in the body, intestinal macrophages are in a state of partial activation showing no response to inflammatory stimuli, no production of pro-inflammatory cytokines and low expression levels of innate response receptors. Although their phenotype is largely characterised, it still remains unclear how they acquire this phenotype and thus exert these anti-inflammatory properties. We optimised a method using cell sorting to isolate intestinal macrophages and characterised their phenotype in homeostasis and inflammation. Furthermore, in order to explore how intestinal macrophages acquire this phenotype we investigated the influence of intestinal epithelial cells on macrophages in vitro by conditioning J774A.1 macrophages with supernatants from the murine colonic epithelial cell line, CMT-93. Conditioned macrophages acquired a regulatory phenotype that resembles the intestinal macrophages, with decreased production of IL-12p40, IL-6 and other pro-inflammatory mediators. Furthermore, conditioned macrophages became less responsive to Toll-like receptor stimulation, while they kept their phagocytic abilities and maintained TNF-α production. Interestingly, higher expression of TNF receptor 2 (TNFR2) was observed in conditioned macrophages. This receptor has been linked with anti-inflammatory and immunosuppressive effects of TNF-α. Our in vivo study on DSS-induced colitis in mice also demonstrated regulation of TNFR2 in the later stage of colitis, correlating with disease resolution. Furthermore, we provide evidence that TNFR2 is also involved in the resolution of disease in the Clostridium difficile model of infection. Our findings show that intestinal epithelial cells can produce factors that change and shape macrophage response and implicate TNFR2 as one of the mechanisms by which intestinal macrophages exert their homeostatic properties. xii PUBLICATIONS Soluble factors from colonic epithelial cells contribute to gut homeostasis by modulating macrophage phenotype (2013)
Macrophage subpopulations in lamina propria of normal and inflamed colon and terminal ileum
Gut, 1989
The aim of this study was to characterise human intestinal macrophages in normal and inflamed ileum and colon. Immunoperoxidase staining with a panel of monoclonal antibodies and histochemical staining for acid phosphatase and non-specific esterase was performed. In the superficial lamina propria, normal colonic macrophages were larger and more strongly positive for acid phosphatase and non-specific esterase than those in normal terminal ileum. There were more macrophages staining with monoclonal antibody RFD1 in the superficial lamina propria of the latter. Studies in inflammatory bowel disease tissue showed the presence of macrophages staining with monoclonal antibodies RFD9 and 3G8 which were rarely present in normal tissue and represented a different pattern from that seen in infectious colitis. Studies on isolated intestinal macrophages confirmed the findings in tissue sections. Subpopulations of intestinal macrophages are likely to have different functional roles. Phenotypic changes during inflammation may be induced by mediators of inflammation or may represent a recently recruited population of cells.