Modulation of constitutive and delayed apoptosis by brefeldin A in human neutrophils.
Neutrophil apoptosis is a constitutive process that can be enhanced or delayed by various stimuli. In this study, the effect of brefeldin A (BFA), which affects the biological process of secretion, on constitutive and delayed apoptosis of neutrophils was investigated. Neutrophil apoptosis was determined after culturing for 20 h in vitro by morphological changes, annexin V staining, and DNA electrophoresis. BFA dose-dependently increased the constitutive apoptotic rate of neutrophils. The delay of apoptosis induced by granulocyte-macrophage colony-stimulating factor (GM-CSF) and lipopolysaccharide (LPS) was also blocked by BFA. However, this effect of BFA was less marked when neutrophils were treated with dexamethasone, interleukin-8 (IL-8), or dibutyryl cAMP (dbcAMP). Moreover, the delay of neutrophil apoptosis induced by rottlerin, a specific inhibitor of protein kinase C (PKC)-delta, was significantly abrogated by BFA. Although BFA-induced apoptosis was not blocked by the caspase-3 inhibitor, zDEVD-fmk, myeloid cell leukemia-1 (Mcl-1) expression levels were downregulated by BFA. These results suggest that derangement of vesicular protein transport may be involved in the apoptosis of neutrophils, and that the action of BFA on apoptosis is dependent on changes in the expression of Mcl-1.
Lee
Min-Jung
MJ
Medical Research Center for Cancer Molecular Therapy, Busan 602-103, South Korea.
Park
Ji-Yeon
JY
Lee
Sun-Young
SY
Lee
Jun-Sik
JS
Jung
Dong-Keun
DK
Bae
Yoe-Sik
YS
Kwak
Jong-Young
JY
D000328:Adult; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D020126:Brefeldin A / Q000494:pharmacology*; D053148:Caspase 3; D061945:Caspase Inhibitors; D053938:DNA Fragmentation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006801:Humans; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D009504:Neutrophils / Q000187:drug effects*; D010716:Phosphatidylinositols / Q000494:pharmacology; D010718:Phosphatidylserines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D051745:Protein Kinase C-delta; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*
D061945:Caspase Inhibitors; D007202:Indicators and Reagents; D010716:Phosphatidylinositols; D010718:Phosphatidylserines; D011500:Protein Synthesis Inhibitors; D020126:Brefeldin A; C497258:PRKCD protein, human; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; C505407:CASP3 protein, human; D053148:Caspase 3