Roscovitine-induced apoptosis in neutrophils and neutrophil progenitors is regulated by the Bcl-2-family members Bim, Puma, Noxa and Mcl-1.
Neutrophil granulocyte (neutrophil) apoptosis plays a key role in determining inflammation in infectious and non-infectious settings. Recent work has shown that inhibitors of cyclin-dependent kinases (cdk) such as roscovitine can potently induce neutrophil apoptosis and reduce inflammation. Using a conditional Hoxb8-expression system we tested the participation of Bcl-2-family proteins to roscovitine-induced apoptosis in mouse neutrophils and in neutrophil progenitor cells. Bcl-2 strongly protected against roscovitine-induced apoptosis in neutrophils. The isolated loss of either Bim or noxa provided significant, partial protection while protection through combined loss of Bim and noxa or Bim and Puma was only slightly greater than this individual loss. The only substantial change in protein levels observed was the loss of Mcl-1, which was not transcriptional and was inhibited by proteasome blockade. In progenitor cells there was no protection by the loss of Bim alone but substantial protection by the loss of both Bim and Puma; surprisingly, strongest protection was seen by the isolated loss of noxa. The pattern of protein expression and Mcl-1-regulation in progenitor cells was very similar to the one observed in differentiated neutrophils. In addition, roscovitine strongly inhibited proliferation in progenitor cells, associated with an accumulation of cells in G2/M-phase.
Institute for Medical Microbiology and Hygiene, University Medical Center, Freiburg, Freiburg, Germany.
Sanjivan
S
Gautam
Susanne
S
Kirschnek
Michael
M
Wiesmeier
Juliane
J
Vier
Georg
G
Häcker
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D000072224:Bcl-2-Like Protein 11; D020169:Caspases / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D064549:Myeloid Cell Leukemia Sequence 1 Protein / Q000378:metabolism; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D011687:Purines / Q000494:pharmacology*; D000077546:Roscovitine; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects*; D025521:Tumor Suppressor Proteins / Q000378:metabolism
D051017:Apoptosis Regulatory Proteins; C000606775:BCL2L11 protein, human; D000072224:Bcl-2-Like Protein 11; C000606776:Bcl2l11 protein, mouse; C579094:Mcl1 protein, mouse; D008565:Membrane Proteins; D064549:Myeloid Cell Leukemia Sequence 1 Protein; C488588:PUMA protein, mouse; C408009:Pmaip1 protein, mouse; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011687:Purines; D025521:Tumor Suppressor Proteins; D000077546:Roscovitine; D020169:Caspases