Costimulation with interleukin-4 and interleukin-10 induces mast cell apoptosis and cell-cycle arrest: the role of p53 and the mitochondrion.
OBJECTIVE
The aim of this study was to determine the mechanism by which interleukin (IL)-4 + IL-10 costimulation regulates mast cell numbers to maintain immune homeostasis.


METHODS
We employed mouse bone marrow-derived mast cells (BMMC) to measure the effects of IL-4 + IL-10 on survival and cell-cycle progression. p53-Deficient, bax-deficient, and bcl-2 transgenic BMMC were compared to wild-type cells to determine the role of these proteins in apoptosis. The molecular regulation of apoptosis and cell-cycle progression was investigated using flow cytometric analysis, RNase protection, and Western blotting.


RESULTS
IL-4 + IL-10 induced BMMC apoptosis and arrest. Apoptosis was p53-dependent. Cell death was accompanied by loss of mitochondrial membrane potential, the importance of which was demonstrated by resistance to IL-4 + IL-10-mediated cell death when Bax was deleted or Bcl-2 was overexpressed. Those cells not killed by apoptosis demonstrated a p53-independent G1 cell-cycle arrest. Apoptosis and arrest may be explained by reduced IL-3 receptor signaling.


CONCLUSIONS
Costimulation with IL-4 + IL-10 partly controls mast cell homeostasis through a delayed apoptosis and arrest program that is induced by a blockade of IL-3 receptor signaling. The delay in these negative effects would allow the protective effects of mast cell activation to occur for several days.
Bouton
L Andrew
LA
Department of Biology, Virginia Commonwealth University, Richmond, Va. 23284-2012, USA.
Ramirez
Carlos D
CD
Bailey
Daniel P
DP
Yeatman
C Fitzhugh
CF
Yue
Joyce
J
Wright
Harry V
HV
Domen
Jos
J
Rosato
Roberto R
RR
Grant
Steven
S
Fischer-Stenger
Krista
K
Ryan
John J
JJ
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D016193:G1 Phase / Q000235:genetics / Q000502:physiology*; D016753:Interleukin-10 / Q000494:pharmacology*; D015847:Interleukin-4 / Q000494:pharmacology*; D008407:Mast Cells / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D016185:Receptors, Interleukin-3 / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000378:metabolism*; D051028:bcl-2-Associated X Protein
C494827:Bax protein, mouse; D019253:Proto-Oncogene Proteins c-bcl-2; D016185:Receptors, Interleukin-3; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D016753:Interleukin-10; D015847:Interleukin-4