Anti-apoptotic effects of Z alpha1-antitrypsin in human bronchial epithelial cells.
alpha(1)-antitrypsin (alpha(1)-AT) deficiency is a genetic disease which manifests as early-onset emphysema or liver disease. Although the majority of alpha(1)-AT is produced by the liver, it is also produced by bronchial epithelial cells, amongst others, in the lung. Herein, we investigate the effects of mutant Z alpha(1)-AT (ZAAT) expression on apoptosis in a human bronchial epithelial cell line (16HBE14o-) and delineate the mechanisms involved. Control, M variant alpha(1)-AT (MAAT)- or ZAAT-expressing cells were assessed for apoptosis, caspase-3 activity, cell viability, phosphorylation of Bad, nuclear factor (NF)-kappaB activation and induced expression of a selection of pro- and anti-apoptotic genes. Expression of ZAAT in 16HBE14o- cells, like MAAT, inhibited basal and agonist-induced apoptosis. ZAAT expression also inhibited caspase-3 activity by 57% compared with control cells (p = 0.05) and was a more potent inhibitor than MAAT. Whilst ZAAT had no effect on the activity of Bad, its expression activated NF-kappaB-dependent gene expression above control or MAAT-expressing cells. In 16HBE14o- cells but not HEK293 cells, ZAAT upregulated expression of cIAP-1, an upstream regulator of NF-kappaB. cIAP1 expression was increased in ZAAT versus MAAT bronchial biopsies. The data suggest a novel mechanism by which ZAAT may promote human bronchial epithelial cell survival.
Dept of Medicine Respiratory Research Division, RCSI Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland. cmgreene@rcsi.ie
C M
CM
Greene
S D W
SD
Miller
T P
TP
Carroll
I K
IK
Oglesby
F
F
Ahmed
M
M
O'Mahony
C C
CC
Taggart
N G
NG
McElvaney
S J
SJ
O'Neill
D000328:Adult; D017209:Apoptosis / Q000187:drug effects*; D001706:Biopsy; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation; D004646:Emphysema / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D006801:Humans; D007124:Immunoenzyme Techniques; D020287:In Situ Nick-End Labeling; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics; D008297:Male; D016328:NF-kappa B / Q000378:metabolism; D010766:Phosphorylation; D020545:Respiratory Mucosa / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation; D000515:alpha 1-Antitrypsin / Q000494:pharmacology*; D019896:alpha 1-Antitrypsin Deficiency / Q000378:metabolism; D051025:bcl-Associated Death Protein / Q000378:metabolism
C494819:BAD protein, human; D051034:Inhibitor of Apoptosis Proteins; D016328:NF-kappa B; D000515:alpha 1-Antitrypsin; D051025:bcl-Associated Death Protein; D053148:Caspase 3