Identification of apoptosis-inducing factor in human coronary artery endothelial cells.
Apoptosis has been observed in vascular tissues in response to pro-inflammatory and pro-atherosclerotic stimuli, such as oxidized low density lipoproteins (ox-LDL), angiotensin II (Ang II), and tumor necrosis factor-alpha (TNF-alpha). Apoptosis is believed to be mediated via caspase-dependent pathway. Recently, a 57 kDa molecule, apoptosis-inducing factor (AIF), has been described as a basis for cell injury via a caspase-independent pathway. This study was designed to identify the presence of AIF and the regulation of its gene expression in human coronary artery endothelial cells (HCAECs). Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to determine AIF mRNA and protein expression. Cultured HCAECs were treated with ox-LDL (10-40 microg/ml), angiotensin II (10(-9)-10(-6)M), or TNF-alpha (0.1-10n g/ml). AIF was barely detectable in unstimulated HCAECs; however, treatment with ox-LDL, but not with Ang II or TNF-alpha, significantly increased the expression of AIF in a concentration- and time-dependent manner. DNA sequencing analysis substantiated the existence of AIF in the HCAECs. Treatment of cells with the caspase inhibitor with Z-VAD-fmk did not change ox-LDL-mediated AIF protein expression. Ox-LDL-mediated upregulation of AIF expression was inhibited by actinomycin D, suggesting transcriptional regulation. Further, upon treatment of cells with ox-LDL AIF translocated from mitochondria to the nucleus, as determined by immunocytochemistry. These data suggest that AIF is expressed in HCAECs and is upregulated by ox-LDL.
Zhang
Wenguang
W
Department of Internal Medicine, Division of Cardiovascular Medicine, University of Arkansas for Medical Sciences, 4301 West Markham, Mail Slot 532, Little Rock, AR 72205-7199, USA.
Shokeen
Madhu
M
Li
Dayuan
D
Mehta
Jawahar L
JL
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology; D051033:Apoptosis Inducing Factor; D001158:Arteries / Q000166:cytology / Q000378:metabolism*; D001483:Base Sequence; D003326:Coronary Circulation; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005420:Flavoproteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D008077:Lipoproteins, LDL / Q000494:pharmacology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015854:Up-Regulation / Q000502:physiology
C494829:AIFM1 protein, human; D000590:Amino Acid Chloromethyl Ketones; D051033:Apoptosis Inducing Factor; D015853:Cysteine Proteinase Inhibitors; D005420:Flavoproteins; D008077:Lipoproteins, LDL; D008565:Membrane Proteins; D019384:Nucleic Acid Synthesis Inhibitors; D014409:Tumor Necrosis Factor-alpha; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C099252:oxidized low density lipoprotein; D000804:Angiotensin II; D003609:Dactinomycin