IFN-γ and dibutyryl cAMP pre-treatment of U937 cells results in different Ca2+ signals triggered by antibody cross-linking of the human high affinity receptor for IgG (FcγRI)

1995 ◽  
Vol 23 (1) ◽  
pp. 122S-122S ◽  
Author(s):  
R. Andres Floto ◽  
Martyn Mahaut-Smith ◽  
Janet M. Allen
Keyword(s):  
Cross Linking ◽  
U937 Cells ◽  
Dibutyryl Camp ◽  
High Affinity ◽  
High Affinity Receptor ◽  
Affinity Receptor ◽  
Ifn Γ ◽  
Pre Treatment

scholarly journals Roles for Ca2+ mobilization and its regulation in mast cell functions: recent progress

2016 ◽  
Vol 44 (2) ◽  
pp. 505-509 ◽  
Author(s):  
David Holowka ◽  
Marcus Wilkes ◽  
Christopher Stefan ◽  
Barbara Baird
Keyword(s):  
Membrane Protein ◽  
Cross Linking ◽  
Recycling Endosomes ◽  
Cell Functions ◽  
High Affinity ◽  
Rho Family Gtpases ◽  
High Affinity Receptor ◽  
Selective Channel ◽  
Affinity Receptor ◽  
Rho Family

Ca2+ mobilization in response to cross-linking of IgE bound to its high affinity receptor, FcεRI, on mast cells is central to immune allergic responses. Stimulated tyrosine phosphorylation caused by this cross-linking activates store-operated Ca2+ entry that results in sustained Ca2+ oscillations dependent on Rho family GTPases and phosphoinositide synthesis. Coupling of the endoplasmic reticulum (ER) Ca2+ sensor, stromal interaction molecule 1 (STIM1), to the Ca2+-selective channel, Orai1, is regulated by these elements and depends on membrane organization, both at the plasma membrane and at the ER. Mitochondria also contribute to the regulation of Ca2+ mobilization, and we describe recent evidence that the ER membrane protein vesicle-associated membrane protein-associated protein (VAP) plays a significant role in the coupling between ER and mitochondria in this process. In addition to granule exocytosis, Ca2+ mobilization in these cells also contributes to stimulated outward trafficking of recycling endosomes and to antigen-stimulated chemotaxis, and it is pathologically regulated by protozoan parasitic invasion.

scholarly journals IL-33 and Superantigenic Activation of Human Lung Mast Cells Induce the Release of Angiogenic and Lymphangiogenic Factors

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 145
Author(s):  
Leonardo Cristinziano ◽  
Remo Poto ◽  
Gjada Criscuolo ◽  
Anne Lise Ferrara ◽  
Maria Rosaria Galdiero ◽  
...  
Keyword(s):  
Mast Cells ◽  
Human Lung ◽  
Protein A ◽  
Protein L ◽  
Variable Regions ◽  
Prolonged Incubation ◽  
High Affinity ◽  
High Affinity Receptor ◽  
Affinity Receptor ◽  
Pleiotropic Functions

Human lung mast cells (HLMCs) express the high-affinity receptor FcεRI for IgE and are strategically located in different compartments of human lung, where they play a role in several inflammatory disorders and cancer. Immunoglobulin superantigens (e.g., protein A of Staphylococcus aureus and protein L of Peptostreptococcus magnus) bind to the variable regions of either the heavy (VH3) or light chain (κ) of IgE. IL-33 is a cytokine expressed by epithelial cells that exerts pleiotropic functions in the lung. The present study investigated whether immunoglobulin superantigens protein A and protein L and IL-33 caused the release of inflammatory (histamine), angiogenic (VEGF-A) and lymphangiogenic (VEGF-C) factors from HLMCs. The results show that protein A and protein L induced the rapid (30 min) release of preformed histamine from HLMCs. By contrast, IL-33 did not induce the release of histamine from lung mast cells. Prolonged incubation (12 h) of HLMCs with superantigens and IL-33 induced the release of VEGF-A and VEGF-C. Preincubation with IL-33 potentiated the superantigenic release of histamine, angiogenic and lymphangiogenic factors from HLMCs. Our results suggest that IL-33 might enhance the inflammatory, angiogenic and lymphangiogenic activities of lung mast cells in pulmonary disorders.

The Temporal Distribution of the 1α,25-Dihydroxycholecalciferol Receptor in the Rat Jejunal Villus

1984 ◽  
Vol 67 (3) ◽  
pp. 285-290 ◽  
Author(s):  
S. D. H. Chan ◽  
D. Atkins
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Calcium Absorption ◽  
Sedimentation Coefficient ◽  
Temporal Distribution ◽  
High Affinity ◽  
High Affinity Receptor ◽  
Affinity Receptor ◽  
Cell Fractions ◽  
Crypt Cells

1. The distribution of the 1α,25-dihydroxycholecalciferol receptor was studied in enterocytes isolated from the upper, mid and lower villus and crypt cells of the jejunum of normal and rachitic rats. 2. In all cell fractions a high-affinity receptor (KD ⋍ 0.07 nmol/l) with a sedimentation coefficient of 3.5S was demonstrated. 3. In normal rats there was a 60% reduction in receptor numbers in crypt cells compared with the mid and upper villous cells. 4. Vitamin D deficiency led to a reduction in receptor numbers in all cell fractions (45% upper villus, 78% crypt cells). 5. The data are compatible with the concept of calcium absorption occurring in the differentiated villous cells and also account for the reduction in absorption in rachitic animals.

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