Research Topics
| MECHANISMS OF HUMAN BASOPHIL & MAST CELL DESENSITIZATIONSummaryPrincipal Investigator: D MacGlashan Affiliation: Johns Hopkins University Country: USA Abstract: Basophil and mast cell mediator release is a central feature of both acute and chronic allergic reactions. However, little is known of the biochemical nature of signal transduction in the human cells of this type. This proposal focuses on studies which will elucidate some of the important biochemical events in both IgE mediated and univalent hormone induced secretion. The primary goals of these studies is to elucidate the mechanisms of desensitization although significant effort will also be applied towards understanding activation events. In particular, the role of cytosolic calcium elevations and protein kinase C in activation and desensitization will be further examined. We have demonstrated that IgE-mediated histamine release in both human basophils and lung mast cells is accompanied by the increased activity of membrane associated protein kinase C and elevations in cytosolic calcium. Detailed studies suggest that desensitization processes are specific for the mediator being examined and that for regulating the extent of degranulation (histamine release), the basophil and mast cell regulate the activation of protein kinase C rather than elevations in cytosolic calcium. Therefore, part of this proposal seeks to understand in greater detail the relationship between PKC activation and histamine release, the multiple roles PKC may play in regulating mediator release and whether the transient activation in PKC activity results from the specific regulation of diacylglycerol levels. A series of exploratory experiments are proposed to determine whether tyrosine kinase activity plays a role in desensitization. Preliminary evidence also suggests that leukotriene release, unlike histamine release, is controlled by the down-regulation of the calcium response. The proposed studies will initially examine the relationship between down-regulation of the calcium response and down- regulation of leukotriene release. A second primary area of study will be on the relationship between calcium oscillations observed in single cells and subsequent mediator release. Several methods are proposed to measure single cell degranulation in an effort to correlate this end point with the early oscillatory changes in cytosolic calcium. In addition, the relationship between calcium oscillations and leukotriene release will be examined. A third aim of this proposal is to study the relationship between desensitization events that affect the early mediators (histamine and leukotrienes) and cytokine secretion which occurs much later in the secretory response. Since cytokine release appears dependent on mRNA accumulation, initial studies will focus on the mechanisms of mRNA accumulation. Funding Period: 1984-12-01 - 1994-08-31 more information: NIH RePORT Top Publications
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Acute IL-3 priming up-regulates the stimulus-induced Raf-1-Mek-Erk cascade independently of IL-3-induced activation of ErkNatalia Vilariño
Johns Hopkins Asthma and Allergy Center, Baltimore, MD 21224, USA
J Immunol 175:3006-14. 2005..This type of preactivation can be mimicked by incubation with the Ser-Thr kinase inhibitors, Ro-81-3220, or bisindoylmaleimide II...
Syk expression in peripheral blood leukocytes, CD34+ progenitors, and CD34-derived basophilsSusan S Ishmael
Johns Hopkins Asthma and Allergy Center, Baltimore, MD 21224, USA
J Leukoc Biol 87:291-300. 2010....
Expression of the high affinity IgE receptor by neutrophils of individuals with allergic asthma is both minimal and insensitive to regulation by serum IgEJuanita Mora
The Department of Immunology Microbiology, Section of Allergy and Immunology, Rush University Medical Center, Chicago, IL 60612, USA
Clin Immunol 132:132-40. 2009....
Polymerization of actin does not regulate desensitization in human basophilsDonald MacGlashan
Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA
J Leukoc Biol 85:627-37. 2009..These studies demonstrate that desensitization is not the result of two signaling pathways once considered relevant to down-regulation of IgE-mediated signaling...
Inducing an anergic state in mast cells and basophils without secretionDonald MacGlashan
Asthma and Allergy Center, Johns Hopkins University, Baltimore, MD 21224, USA
J Allergy Clin Immunol 121:1500-6, 1506.e1-4. 2008..IgE-mediated secretion from mast cells or basophils depends on the activity of both spleen tyrosine kinase (syk) and phosphatidyl inositol 3' kinase (PI3K), but several specific downregulatory pathways (eg, loss of syk expression) do not...
Distinct characteristics of signal transduction events by histamine-releasing factor/translationally controlled tumor protein (HRF/TCTP)-induced priming and activation of human basophilsBecky M Vonakis
The Johns Hopkins Asthma and Allergy Center, Baltimore, MD 21224, USA
Blood 111:1789-96. 2008..This finding is different from IL-3, which also primes basophils for histamine release, but does show phosphorylation of these events. We conclude that priming induced by HRF/TCTP is distinct from that induced by IL-3...
Endocytosis, recycling, and degradation of unoccupied FcepsilonRI in human basophilsDonald W Macglashan
Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA
J Leukoc Biol 82:1003-10. 2007..These studies establish that the unoccupied receptor is lost by a process of endocytosis, partially recycled to the cell surface, and ultimately degraded by a lysosomal mechanism...
Relationship between spleen tyrosine kinase and phosphatidylinositol 5' phosphatase expression and secretion from human basophils in the general populationDonald W Macglashan
Johns Hopkins Asthma and Allergy Center, Baltimore, MD 21224, USA
J Allergy Clin Immunol 119:626-33. 2007..Previous studies have suggested that expression levels of spleen tyrosine kinase (syk) or phosphatidylinositol 5' phosphatase (SHIP) may explain certain extreme human basophil phenotypes...
Nonspecific desensitization, functional memory, and the characteristics of SHIP phosphorylation following IgE-mediated stimulation of human basophilsDonald MacGlashan
Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Center, Baltimore, MD 21224, USA
J Immunol 177:1040-51. 2006....
Regulation of Fc epsilon RI expression during murine basophil maturation: the interplay between IgE, cell division, and Fc epsilon RI synthetic rateAsifa K Zaidi
Division of Allergy and Clinical Immunology, Asthma and Allergy Center, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
J Immunol 184:1463-74. 2010..The studies also support a model whereby receptor expression is limited by cell division and that basophils, once mature, slow their rate of receptor synthesis...
