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.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI020253-16
Application #
6169700
Study Section
Special Emphasis Panel (ZRG1-IMB (02))
Program Officer
Plaut, Marshall
Project Start
1984-12-01
Project End
2004-06-30
Budget Start
2000-07-01
Budget End
2001-06-30
Support Year
16
Fiscal Year
2000
Total Cost
$349,574
Indirect Cost
Name
Johns Hopkins University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218
MacGlashan Jr, Donald W; Savage, Jessica H; Wood, Robert A et al. (2012) Suppression of the basophil response to allergen during treatment with omalizumab is dependent on 2 competing factors. J Allergy Clin Immunol 130:1130-1135.e5
MacGlashan Jr, Donald (2012) Marked differences in the signaling requirements for expression of CD203c and CD11b versus CD63 expression and histamine release in human basophils. Int Arch Allergy Immunol 159:243-52
MacGlashan Jr, Donald; Honigberg, Lee A; Smith, Ashley et al. (2011) Inhibition of IgE-mediated secretion from human basophils with a highly selective Bruton's tyrosine kinase, Btk, inhibitor. Int Immunopharmacol 11:475-9
Ishmael, Susan S; MacGlashan Jr, Donald W (2010) Syk expression in peripheral blood leukocytes, CD34+ progenitors, and CD34-derived basophils. J Leukoc Biol 87:291-300
Zaidi, Asifa K; Saini, Sarbjit S; Macglashan Jr, Donald W (2010) Regulation of Syk kinase and FcRbeta expression in human basophils during treatment with omalizumab. J Allergy Clin Immunol 125:902-908.e7
MacGlashan Jr, D (2010) Expression of CD203c and CD63 in human basophils: relationship to differential regulation of piecemeal and anaphylactic degranulation processes. Clin Exp Allergy 40:1365-77
Zaidi, Asifa K; MacGlashan, Donald W (2010) Regulation of Fc epsilon RI expression during murine basophil maturation: the interplay between IgE, cell division, and Fc epsilon RI synthetic rate. J Immunol 184:1463-74
Mora, Juanita; Riggs, Emily K; Fu, Jun et al. (2009) Expression of the high affinity IgE receptor by neutrophils of individuals with allergic asthma is both minimal and insensitive to regulation by serum IgE. Clin Immunol 132:132-40
MacGlashan Jr, Donald; VilariƱo, Natalia (2009) Polymerization of actin does not regulate desensitization in human basophils. J Leukoc Biol 85:627-37
MacGlashan Jr, Donald; Undem, Bradley J (2008) Inducing an anergic state in mast cells and basophils without secretion. J Allergy Clin Immunol 121:1500-6, 1506.e1-4

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