NKG2D recognition mediates Toll-like receptor 3 signaling-induced breakdown of epithelial homeostasis in the small intestines of mice

Toll-like receptors (TLRs) and NK receptors are the two most important receptor families in innate immunity. Although it has been observed that TLR signaling can induce or up-regulate the expression of the ligands for stimulatory NK receptors on monocytes or muscle cells, there is not yet a report indicating whether TLR signaling can break down self-tolerance through NK receptors. The present work reports that TLR3 signaling by polyinosinic–polycytidylic acid stimulation induces intestinal epithelial cells (IECs) to express retinoic acid early inducible-1 (a ligand for NKG2D) and to induce NKG2D expression on CD8αα intestinal intraepithelial lymphocytes by IL-15 derived from TLR3-activated IECs. The blockade of interaction between NKG2D and Rae1 inhibits the cytotoxicity of intraepithelial lymphocytes against IECs in a cell–cell contact-dependent manner and therefore alleviates polyinosinic–polycytidylic acid-induced epithelial destruction and acute mucosal injury of small intestine. These results demonstrate that TLR signaling induces tissue injury through the NKG2D pathway, suggesting that TLR signaling may break down self-tolerance through induction of abnormal expression of ligands for stimulatory NK receptors.

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Interaction with Mesenchymal Stem Cells Provokes Natural Killer Cells for Enhanced IL-12/IL-18-Induced Interferon-Gamma Secretion

Mediators of Inflammation ◽

10.1155/2014/143463 ◽

2014 ◽

Vol 2014 ◽

pp. 1-11 ◽

Cited By ~ 32

Author(s):

Heike Thomas ◽

Marcus Jäger ◽

Katharina Mauel ◽

Sven Brandau ◽

Sara Lask ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Nk Cells ◽

Natural Killer ◽

Tissue Regeneration ◽

Tissue Injury ◽

Cell Contact ◽

Dependent Manner ◽

Close Proximity ◽

Dose Dependent

Tissue injury induces an inflammatory response accompanied by the recruitment of immune cells and of mesenchymal stem cells (MSC) that contribute to tissue regeneration. After stimulation with interleukin- (IL-) 12 and IL-18 natural killer (NK) cells secrete the proinflammatory cytokine interferon- (IFN-)γ. IFN-γplays a crucial role in the defense against infections and modulates tissue regeneration. In consideration of close proximity of NK cells and MSC at the site of injury we investigated if MSC could influence the ability of NK-cells to produce IFN-γ. Coculture experiments were performed with bone marrow-derived human MSC and human NK cells. MSC enhanced the ability of IL-12/IL-18-stimulated NK cells to secrete IFN-γin a dose-dependent manner. This activation of NK cells was dependent on cell-cell contact as well as on soluble factors. The increased IFN-γsecretion from NK cells after contact with MSC correlated with an increased level of intracellular IFN-γ. Alterations in the IL-12 signaling pathway including an increased expression of the IL-12β1 receptor subunit and an increased phosphorylation of signal transducer and activator of transcription 4 (STAT4) could be observed. In conclusion, MSC enhance the IFN-γrelease from NK cells which might improve the defense against infections at the site of injury but additionally might affect tissue regeneration.

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PSX-41 Effect of Polyinosinic-polycytidylic acid on gene expression in goat blood

Journal of Animal Science ◽

10.1093/jas/skz258.884 ◽

2019 ◽

Vol 97 (Supplement_3) ◽

pp. 449-449

Author(s):

Kingsley Ekwemalor ◽

Mulumebet Worku

Keyword(s):

Gene Expression ◽

Signaling Pathway ◽

Group Treatment ◽

Fold Change ◽

Poly I:C ◽

Control Group ◽

Tlr Signaling ◽

Polycytidylic Acid ◽

Tlr Signaling Pathway ◽

Polyinosinic Polycytidylic Acid

Abstract The objective of this study was to investigate the effect of Polyinosinic-polycytidylic [poly(I:C)] acid on gene activation in goat blood. Polyinosinic-polycytidylic acid is a synthetic dsRNA analogue that binds to Toll-like receptor (TLR) 3. Synthetic TLR agonists are promising immune modulators. Blood samples were collected from the jugular vein of BoerXSpanish goats (n = 3) into tubes containing an anticoagulant. Whole blood was treated with the 12.5 µg/ml of poly I:C or 200µl of PBS which served as control. Cells were incubated at 37°C with 5% CO2 and 85% humidity for 30 minutes. Total RNA was isolated from the pellet using Trizol and then converted to cDNA using RETROscript kit (Qiagen). The expression of 84 genes in the human TLR signaling pathway RT2 PCR Array was evaluated using real-time PCR. Fold change in gene expression was calculated using the 2−ΔΔCt method. The housekeeping gene GAPDH, ACTB, HPRT1, TBP, and YWHAZ was used to normalize the data. Fold change was set at a cutoff of 2. Following treatment with poly I:C, 24 genes were up-regulated, 15 genes were down-regulated. The gene MAPK8 was induced by poly I:C treatment. Only 74 genes were expressed in the control. Thirty-nine genes were expressed in both the control group and poly I:C treatment group. Treatment with poly I:C also down-regulated some of the genes tested. Our results show that treatment poly I:C modulated the expression of genes in the TLR signaling pathway and provides insights into how goats respond to viral pathogens for the design of adjuvants to enhance the immune response.

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GMP-140 mediates adhesion of stimulated platelets to neutrophils

Blood ◽

10.1182/blood.v75.3.550.550 ◽

1990 ◽

Vol 75 (3) ◽

pp. 550-554 ◽

Cited By ~ 352

Author(s):

SA Hamburger ◽

RP McEver

Keyword(s):

Tissue Injury ◽

Leukocyte Adhesion ◽

Sequence Similarity ◽

Secretory Granules ◽

Human Platelets ◽

Cell Contact ◽

Dependent Manner ◽

Cellular Activation

Abstract In vivo, platelets associate with neutrophils at sites of hemorrhage or inflammation. In vitro, stimulated platelets bind to neutrophils in a Ca2(+)-dependent manner. GMP-140, an integral membrane glycoprotein found in secretory granules of platelets and endothelium, is rapidly translocated to the cell surface after cellular activation. It shares sequence similarity with two leukocyte adhesion molecules, ELAM-1 and a lymphocyte homing receptor. We have recently shown that neutrophils bind to purified GMP-140 in a Ca2(+)-dependent fashion, and that GMP- 140 participates in adhesion of neutrophils to activated endothelium. In this study we demonstrate that GMP-140 also mediates adhesion of neutrophils to stimulated platelets. Fixed thrombin-activated human platelets, but not unstimulated platelets, formed rosettes around neutrophils in the presence of Ca2+. The binding of platelets to neutrophils was inhibited by a monoclonal antibody to GMP-140 and by purified GMP-140. By promoting close cell-cell contact, GMP-140 may recruit both platelets and neutrophils to sites of tissue injury as well as modulate the function of each cell type by the other.

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GMP-140 mediates adhesion of stimulated platelets to neutrophils

Blood ◽

10.1182/blood.v75.3.550.bloodjournal753550 ◽

1990 ◽

Vol 75 (3) ◽

pp. 550-554 ◽

Cited By ~ 1

Author(s):

SA Hamburger ◽

RP McEver

Keyword(s):

Tissue Injury ◽

Leukocyte Adhesion ◽

Sequence Similarity ◽

Secretory Granules ◽

Human Platelets ◽

Cell Contact ◽

Dependent Manner ◽

Cellular Activation

In vivo, platelets associate with neutrophils at sites of hemorrhage or inflammation. In vitro, stimulated platelets bind to neutrophils in a Ca2(+)-dependent manner. GMP-140, an integral membrane glycoprotein found in secretory granules of platelets and endothelium, is rapidly translocated to the cell surface after cellular activation. It shares sequence similarity with two leukocyte adhesion molecules, ELAM-1 and a lymphocyte homing receptor. We have recently shown that neutrophils bind to purified GMP-140 in a Ca2(+)-dependent fashion, and that GMP- 140 participates in adhesion of neutrophils to activated endothelium. In this study we demonstrate that GMP-140 also mediates adhesion of neutrophils to stimulated platelets. Fixed thrombin-activated human platelets, but not unstimulated platelets, formed rosettes around neutrophils in the presence of Ca2+. The binding of platelets to neutrophils was inhibited by a monoclonal antibody to GMP-140 and by purified GMP-140. By promoting close cell-cell contact, GMP-140 may recruit both platelets and neutrophils to sites of tissue injury as well as modulate the function of each cell type by the other.

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