The Inhibition of Mast Cell Activation of Radix Paeoniae alba Extraction Identified by TCRP Based and Conventional Cell Function Assay Systems

Intraurethral inoculation of mice with uropathogenic E. coli (CP1) results in prostate inflammation, fibrosis, and urinary dysfunction, recapitulating some but not all of the pathognomonic clinical features associated with benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS). In both patients with LUTS and in CP1-infected mice, we observed increased numbers and activation of mast cells and elevated levels of prostate fibrosis. Therapeutic inhibition of mast cells using a combination of mast cell stabilizer (MCS), cromolyn sodium, and the histamine 1 receptor antagonist (H1RA), cetirizine di-hydrochloride, in the mouse model resulted in reduced mast cell activation in the prostate and significant alleviation of urinary dysfunction. Treated mice showed reduced prostate fibrosis, less infiltration of immune cells, and decreased inflammation. In addition, as opposed to symptomatic CP1-infected mice, treated mice showed reduced myosin light chain (MLC)-2 phosphorylation, a marker of prostate smooth muscle contraction. These results show that mast cells play a critical role in the pathophysiology of urinary dysfunction and may be an important therapeutic target for men with BPH/LUTS.

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Mast cell activation is enhanced by Tim1:Tim4 interaction but not by Tim-1 antibodies

F1000Research ◽

10.12688/f1000research.8132.2 ◽

2016 ◽

Vol 5 ◽

pp. 251

Author(s):

Binh Phong ◽

Lawrence P. Kane

Keyword(s):

Mast Cell ◽

Mast Cells ◽

Signaling Pathways ◽

Cell Activation ◽

Molecular Mechanisms ◽

Cell Function ◽

Immune Cell ◽

Allergic Diseases ◽

Mast Cell Activation ◽

High Affinity Ige Receptor

Polymorphisms in theT cell (or transmembrane) immunoglobulin and mucin domain 1(TIM-1) gene, particularly in the mucin domain, have been associated with atopy and allergic diseases in mice and human. Genetic- and antibody-mediated studies revealed that Tim-1 functions as a positive regulator of Th2 responses, while certain antibodies to Tim-1 can exacerbate or reduce allergic lung inflammation. Tim-1 can also positively regulate the function of B cells, NKT cells, dendritic cells and mast cells. However, the precise molecular mechanisms by which Tim-1 modulates immune cell function are currently unknown. In this study, we have focused on defining Tim-1-mediated signaling pathways that enhance mast cell activation through the high affinity IgE receptor (FceRI). Using a Tim-1 mouse model lacking the mucin domain (Tim-1Dmucin), we show for the first time that the polymorphic Tim-1 mucin region is dispensable for normal mast cell activation. We further show that Tim-4 cross-linking of Tim-1 enhances select signaling pathways downstream of FceRI in mast cells, including mTOR-dependent signaling, leading to increased cytokine production but without affecting degranulation.

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Mast cell activation is enhanced by Tim1:Tim4 interaction but not by Tim-1 antibodies

F1000Research ◽

10.12688/f1000research.8132.1 ◽

2016 ◽

Vol 5 ◽

pp. 251

Author(s):

Binh Phong ◽

Lawrence P. Kane

Keyword(s):

Mast Cell ◽

Mast Cells ◽

Signaling Pathways ◽

Cell Activation ◽

Molecular Mechanisms ◽

Cell Function ◽

Immune Cell ◽

Allergic Diseases ◽

Mast Cell Activation ◽

High Affinity Ige Receptor

Polymorphisms in theT cell (or transmembrane) immunoglobulin and mucin domain 1(TIM-1) gene, particularly in the mucin domain, have been associated with atopy and allergic diseases in mice and human. Genetic- and antibody-mediated studies revealed that Tim-1 functions as a positive regulator of Th2 responses, while certain antibodies to Tim-1 can exacerbate or reduce allergic lung inflammation. Tim-1 can also positively regulate the function of B cells, NKT cells, dendritic cells and mast cells. However, the precise molecular mechanisms by which Tim-1 modulates immune cell function are currently unknown. In this study, we have focused on defining Tim-1-mediated signaling pathways that enhance mast cell activation through the high affinity IgE receptor (FceRI). Using a Tim-1 mouse model lacking the mucin domain (Tim-1Dmucin), we show for the first time that the polymorphic Tim-1 mucin region is dispensable for normal mast cell activation. We further show that Tim-4 cross-linking of Tim-1 enhances select signaling pathways downstream of FceRI in mast cells, including mTOR-dependent signaling, leading to increased cytokine production but without affecting degranulation.

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Rcan1 negatively regulates FcɛRI-mediated signaling and mast cell function

Journal of Experimental Medicine ◽

10.1084/jem.20081140 ◽

2009 ◽

Vol 206 (1) ◽

pp. 195-207 ◽

Cited By ~ 27

Author(s):

Yong Jun Yang ◽

Wei Chen ◽

Alexander Edgar ◽

Bo Li ◽

Jeffery D. Molkentin ◽

...

Keyword(s):

Mast Cell ◽

Cell Activation ◽

Cytokine Production ◽

Cell Function ◽

Immunoglobulin E ◽

Quantitative Polymerase Chain Reaction ◽

Late Phase ◽

Negative Regulator ◽

Mast Cell Activation ◽

Nuclear Factor

Aggregation of the high affinity IgE receptor (FcɛRI) activates a cascade of signaling events leading to mast cell activation. Subsequently, inhibitory signals are engaged for turning off activating signals. We identified that regulator of calcineurin (Rcan) 1 serves as a negative regulator for turning off FcɛRI-mediated mast cell activation. FcɛRI-induced Rcan1 expression was identified by suppression subtractive hybridization and verified by real-time quantitative polymerase chain reaction and Western blotting. Deficiency of Rcan1 led to increased calcineurin activity, increased nuclear factor of activated T cells and nuclear factor κB activation, increased cytokine production, and enhanced immunoglobulin E–mediated late-phase cutaneous reactions. Forced expression of Rcan1 in wild-type or Rcan1-deficient mast cells reduced FcɛRI-mediated cytokine production. Rcan1 deficiency also led to increased FcɛRI-mediated mast cell degranulation and enhanced passive cutaneous anaphylaxis. Analysis of the Rcan1 promoter identified a functional Egr1 binding site. Biochemical and genetic evidence suggested that Egr1 controls Rcan1 expression. Our results identified Rcan1 as a novel inhibitory signal in FcɛRI-induced mast cell activation and established a new link of Egr1 and Rcan1 in FcɛRI signaling.

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Independent and Cooperative Roles of Adaptor Molecules in Proximal Signaling during FcεRI-Mediated Mast Cell Activation

Molecular and Cellular Biology ◽

10.1128/mcb.00305-10 ◽

2010 ◽

Vol 30 (17) ◽

pp. 4188-4196 ◽

Cited By ~ 14

Author(s):

Taku Kambayashi ◽

Mariko Okumura ◽

Rebecca G. Baker ◽

Chih-Jung Hsu ◽

Tobias Baumgart ◽

...

Keyword(s):

Mast Cell ◽

Plasma Membrane ◽

Mast Cells ◽

Cell Activation ◽

Cell Function ◽

Mast Cell Activation ◽

Membrane Recruitment ◽

Signaling Complex ◽

And Function ◽

Proximal Signaling

ABSTRACT Activation through FcεRI, a high-affinity IgE-binding receptor, is critical for mast cell function during allergy. The formation of a multimolecular proximal signaling complex nucleated by the adaptor molecules SLP-76 and LAT1 is required for activation through this receptor. Based on previous T-cell studies, current dogma dictates that LAT1 is required for plasma membrane recruitment and function of SLP-76. Unexpectedly, we found that the recruitment and phosphorylation of SLP-76 were preserved in LAT1−/− mast cells and that SLP-76−/− and LAT1−/− mast cells harbored distinct functional and biochemical defects. The LAT1-like molecule LAT2 was responsible for the preserved membrane localization and phosphorylation of SLP-76 in LAT1−/− mast cells. Although LAT2 supported SLP-76 phosphorylation and recruitment to the plasma membrane, LAT2 only partially compensated for LAT1-mediated cell signaling due to its decreased ability to stabilize interactions with phospholipase Cγ (PLCγ). Comparison of SLP-76−/− LAT1−/− and SLP-76−/− mast cells revealed that some functions of LAT1 could occur independently of SLP-76. We propose that while SLP-76 and LAT1 depend on each other for many of their functions, LAT2/SLP-76 interactions and SLP-76-independent LAT1 functions also mediate a positive signaling pathway downstream of FcεRI in mast cells.

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