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Publication: MAPK kinase 3 regulates FcεRI-mediated IL-4 production by Mast cells.

Published in the Journal of Immunology by MacNeil, Yang and Lin, the authors discuss the central role of mast cells in allergic inflammation. The focus is on the signaling mechanisms regulating specific mediator release, particularly FcεRI-mediated IL-4 production by mast cells, which is regulated by MAPK Kinase 3 (MKK3).

Among a range of products, MD Bioproducts Total IgE ELISA was cited. We provide a very brief overview of the methods that were performed but highly suggest obtaining the full publication for detailed information regarding the research.

Objective:

  • Determine the role of mast cells in allergic inflammation
  • Investigate mechanism by which MKK3 regulates FcεRI-mediated mast-cell activation

Methods:

In vivo: MKK3 knockout animals and mast cell-deficient W-sh mice were used in an in vivo model of Passive cutaneous anaphylaxis. The mast cell deficient mice received Mouse bone marrow derived mast cells (BMMC) 5 weeks prior to the PCA sensitization. Ear punches were collected for immunohistochemistry to evaluate IL-4 expession. MKK3-deficient mice were analyzed for any defect in basal serum IgE levels.

In vitro: Bone marrow derived mast cells from MKK3 knockout mice were cultured in conditioned media with IL-3 and PGE2. Mast cell purity was determined by staining with toluidine blue. Western blot analysis confirms the absense of MKK3 expression in the knockout BMMCs. The cells are sensitized with anti-TNP IgE and analyzed by flow cytometry. Intracellular calcium flux analysis was performed following activation. BMMCs were also analyzed for phosphorylation following activation. Cytokine analysis was performed to evaluate a panel of cytokines, which are known to contribute to the late-phase allergic reaction. Nuclear proteins from the IgE-sensitized and treated/untreated BMMCs were analyzed for Egr transcription.

Applications: array, ELISA, flow cytometry, immunohistochemistry, immunofluoresence, EMSA, western blotting

Results/Findings:

  • Activated mast cells were shown to play a role in the development of late-phase allergic reactions through the production and release of cytokines. 
  • MKK3-deficient mice exhibited a deficit  in IgE/Ag-dependent inflammation in the PCA model, assessed by tissue thickness in the ear and foot, which suggests a regulatory role for MKK3 in allergic reaction.
  • Mast cells develop normally in vivo and in vitro in the absence of MKK3
  • MKK3 is a signaling target downstream of FcεRI in activated mast cells
  • MKK3 activity is specific to p38 in mast cells activated through FcεRI and that MKK3 is required for full activation of p38
  • MKK3 activity in activated mast cells contributes to signals that promote production of IL-4.
  • Egr1 is specifcaly expressed and activated through an MKK3-dependent signaling mechanism in FcεRI-activated mast cells. 

Summary

The role of MKK3 as a regulator of FcεRI-mediated allergic inflammation was largely unknown prior to this study. Further work in other inflammation models such as Rheumatoid Arthritis also indicates that MKK3 could also play a role in MKK3-dependent TNF signaling in the joint synoivum indicating a potential secondary inflammatory deficiency.

 

MD Bioproducts Total IgE ELISA in this publication:  Total IgE

MKK3-deficient mice were evaluted for Total IgE levels. 

SampleTotal IgE levels
serum from MKK3-deficient mice1.04 ± 1.03 µg/mL
serum from wild-type mice1.00 ± 0.64 µg/mL