| 1. |
- Ekoff, Maria, et al.
(författare)
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The BH3-only protein Puma plays an essential role in cytokine deprivation-induced apoptosis of mast cells
- 2007
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 110:9, s. 3209-3217
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Tidskriftsartikel (refereegranskat)abstract
- Mast cells play critical roles in the regulation of inflammation. One characteristic feature of mast cells is their relatively long lifespan in vivo. Members of the Bcl-2 protein family are regulators of cell survival and apoptosis, where the BH3-only proteins are critical proapoptotic proteins. In this study we investigated the role of the BH3-only proteins Noxa, Bad, Bim, Bmf, Bid, and Puma in apoptosis of mucosal-like mast cells (MLMCs) and connective tissue-like mast cells (CTLMCs). We demonstrate that Puma is critical for the induction of mast-cell death following cytokine deprivation and treatment with the DNA-damaging agent etoposide in MLMCs and CTLMCs. Using p53-/- mast cells, we found that cytokine deprivation-induced apoptosis, in contrast to that elicited by etoposide, is p53-independent. Interestingly, mast cells deficient in FOXO3a, previously proposed as a transcription factor for Puma induction in response to growth factor deprivation, were markedly resistant to cytokine withdrawal compared with wildtype cells. Moreover, overexpression of phosphorylation-deficient, constitutively active FOXO3a caused an up-regulation of Puma. In conclusion, our data demonstrate a pivotal role for Puma in the regulation of cytokine deprivation-induced mast-cell apoptosis and suggest a plausible role for Puma in the regulation of mast cell numbers in vivo. © 2007 by The American Society of Hematology.
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| 2. |
- Möller, Christine, et al.
(författare)
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Bcl-2 and Bcl-XL are indispensable for the late phase of mast cell development from mouse embryonic stem cells
- 2007
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Ingår i: Experimental Hematology. - : Elsevier BV. - 0301-472X .- 1873-2399. ; 35:3, s. 385-393
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Tidskriftsartikel (refereegranskat)abstract
- Objective. The aim of this study was to determine the importance of the prosurvival factors Bcl-2 and Bcl-XL for mast cell development and survival. Methods. bcl-x-/- and bcl-2-/- mouse embryonic stem cells were maintained in medium supplemented with either interleukin (IL)-3 or IL-3 in combination with stem cell factor (SCF) to favor mast cell development. The development of Bcl-2 family deficient embryonic stem cell-derived mast cells (ESMCs) was monitored and Bcl-2 family gene expression and cell numbers were analyzed. Results. Deficiency in either bcl-x or bcl-2 totally inhibited the development of ESMCs when IL-3 alone was used as a mast cell growth factor. Intriguingly, when IL-3 was used in combination with SCF, the ESMCs developed normally the first 2 weeks but thereafter the cell numbers dropped drastically. The remaining ESMCs express mouse mast cell protease 1, suggesting a mucosal-like phenotype. ESMCs lacking bcl-x or bcl-2 exhibited strong expression of Al, another prosurvival Bcl-2 family member. Conclusion. For the first time we provide direct evidence that both bcl-x and bcl-2 are indispensable for mast cell survival during the late phase of their development.
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