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Anti-apoptotic BFL-1 is the major effector in activation-induced human mast cell survival.

Ekoff M, Lyberg K, Krajewska M, Arvidsson M, Rak S, Reed JC, Harvima I, Nilsson G - PLoS ONE (2012)

Bottom Line: FcεRI crosslinking promotes activation-induced survival of human mast cells and this is associated with an upregulation of the anti-apoptotic Bcl-2 family member Bfl-1.ABT-737 alone or in combination with roscovitine decreases viability of human mast cells although activation-induced survival is sustained, indicating a minor role for Bcl-X(L), Bcl-2, Bcl-w and Mcl-1.Taken together, our results highlight Bfl-1 as a major effector in activation-induced human mast cell survival.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Centre for Allergy Research, Karolinska Institutet, Stockholm, Sweden. maria.ekoff@ki.se

ABSTRACT
Mast cells are best known for their role in allergic reactions, where aggregation of FcεRI leads to the release of mast cell mediators causing allergic symptoms. The activation also induces a survival program in the cells, i.e., activation-induced mast cell survival. The aim of the present study was to investigate how the activation-induced survival is mediated. Cord blood-derived mast cells and the mast cell line LAD-2 were activated through FcεRI crosslinking, with or without addition of chemicals that inhibit the activity or expression of selected Bcl-2 family members (ABT-737; roscovitine). Cell viability was assessed using staining and flow cytometry. The expression and function of Bcl-2 family members BFL-1 and MCL-1 were investigated using real-time quantitative PCR and siRNA treatment. The mast cell expression of Bfl-1 was investigated in skin biopsies. FcεRI crosslinking promotes activation-induced survival of human mast cells and this is associated with an upregulation of the anti-apoptotic Bcl-2 family member Bfl-1. ABT-737 alone or in combination with roscovitine decreases viability of human mast cells although activation-induced survival is sustained, indicating a minor role for Bcl-X(L), Bcl-2, Bcl-w and Mcl-1. Reducing BFL-1 but not MCL-1 levels by siRNA inhibited activation-induced mast cell survival. We also demonstrate that mast cell expression of Bfl-1 is elevated in birch-pollen-provocated skin and in lesions of atopic dermatitis and psoriasis patients. Taken together, our results highlight Bfl-1 as a major effector in activation-induced human mast cell survival.

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IgECL-induced survival of human mast cells.(A). CBMC upon IgECL. (B) LAD-2 cells upon IgECL. Cells were sensitized with 1 μg/mL of IgE overnight before cytokine-deprived and challenged with anti-IgE. After 24 hrs the cell viability was enumerated using trypan blue exclusion. N=3–4.
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pone-0039117-g001: IgECL-induced survival of human mast cells.(A). CBMC upon IgECL. (B) LAD-2 cells upon IgECL. Cells were sensitized with 1 μg/mL of IgE overnight before cytokine-deprived and challenged with anti-IgE. After 24 hrs the cell viability was enumerated using trypan blue exclusion. N=3–4.

Mentions: IgECL has been shown to promote survival of mast cells cultured in the absence of their required growth factors [7], [8], [9]. We therefore investigated the survival capacity of human cytokine-deprived cord blood-derived mast cells (CBMCs) and the human mast cell line LAD-2 following IgECL using a fixed concentration of human IgE (1 μg/ml) and 0.2, 2 or 20 μg/ml of anti-human IgE. The results show that IgECL resulted in prolonged survival of cytokine-deprived CBMCs for all anti-human IgE concentrations tested (Fig. 1A). Also LAD-2 cells responded with an increased survival after activation with 2 μg/ml of anti-human IgE (Fig. 1B). For further studies the concentration of 2 μg/ml of anti-human IgE was chosen since the results indicated that this concentration is superior (P=0.039 and 0.031 respectively) as compared to 0.2 and 20 μg/ml for achieving activation-induced survival of CBMCs and LAD-2 cells.


Anti-apoptotic BFL-1 is the major effector in activation-induced human mast cell survival.

Ekoff M, Lyberg K, Krajewska M, Arvidsson M, Rak S, Reed JC, Harvima I, Nilsson G - PLoS ONE (2012)

IgECL-induced survival of human mast cells.(A). CBMC upon IgECL. (B) LAD-2 cells upon IgECL. Cells were sensitized with 1 μg/mL of IgE overnight before cytokine-deprived and challenged with anti-IgE. After 24 hrs the cell viability was enumerated using trypan blue exclusion. N=3–4.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3376125&req=5

pone-0039117-g001: IgECL-induced survival of human mast cells.(A). CBMC upon IgECL. (B) LAD-2 cells upon IgECL. Cells were sensitized with 1 μg/mL of IgE overnight before cytokine-deprived and challenged with anti-IgE. After 24 hrs the cell viability was enumerated using trypan blue exclusion. N=3–4.
Mentions: IgECL has been shown to promote survival of mast cells cultured in the absence of their required growth factors [7], [8], [9]. We therefore investigated the survival capacity of human cytokine-deprived cord blood-derived mast cells (CBMCs) and the human mast cell line LAD-2 following IgECL using a fixed concentration of human IgE (1 μg/ml) and 0.2, 2 or 20 μg/ml of anti-human IgE. The results show that IgECL resulted in prolonged survival of cytokine-deprived CBMCs for all anti-human IgE concentrations tested (Fig. 1A). Also LAD-2 cells responded with an increased survival after activation with 2 μg/ml of anti-human IgE (Fig. 1B). For further studies the concentration of 2 μg/ml of anti-human IgE was chosen since the results indicated that this concentration is superior (P=0.039 and 0.031 respectively) as compared to 0.2 and 20 μg/ml for achieving activation-induced survival of CBMCs and LAD-2 cells.

Bottom Line: FcεRI crosslinking promotes activation-induced survival of human mast cells and this is associated with an upregulation of the anti-apoptotic Bcl-2 family member Bfl-1.ABT-737 alone or in combination with roscovitine decreases viability of human mast cells although activation-induced survival is sustained, indicating a minor role for Bcl-X(L), Bcl-2, Bcl-w and Mcl-1.Taken together, our results highlight Bfl-1 as a major effector in activation-induced human mast cell survival.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Centre for Allergy Research, Karolinska Institutet, Stockholm, Sweden. maria.ekoff@ki.se

ABSTRACT
Mast cells are best known for their role in allergic reactions, where aggregation of FcεRI leads to the release of mast cell mediators causing allergic symptoms. The activation also induces a survival program in the cells, i.e., activation-induced mast cell survival. The aim of the present study was to investigate how the activation-induced survival is mediated. Cord blood-derived mast cells and the mast cell line LAD-2 were activated through FcεRI crosslinking, with or without addition of chemicals that inhibit the activity or expression of selected Bcl-2 family members (ABT-737; roscovitine). Cell viability was assessed using staining and flow cytometry. The expression and function of Bcl-2 family members BFL-1 and MCL-1 were investigated using real-time quantitative PCR and siRNA treatment. The mast cell expression of Bfl-1 was investigated in skin biopsies. FcεRI crosslinking promotes activation-induced survival of human mast cells and this is associated with an upregulation of the anti-apoptotic Bcl-2 family member Bfl-1. ABT-737 alone or in combination with roscovitine decreases viability of human mast cells although activation-induced survival is sustained, indicating a minor role for Bcl-X(L), Bcl-2, Bcl-w and Mcl-1. Reducing BFL-1 but not MCL-1 levels by siRNA inhibited activation-induced mast cell survival. We also demonstrate that mast cell expression of Bfl-1 is elevated in birch-pollen-provocated skin and in lesions of atopic dermatitis and psoriasis patients. Taken together, our results highlight Bfl-1 as a major effector in activation-induced human mast cell survival.

Show MeSH
Related in: MedlinePlus