Monocrotaline pyrrole induces apoptosis in pulmonary artery endothelial cells.
In the monocrotaline (MCT) model of pulmonary hypertension, the pulmonary vascular endothelium is the likely early target of the reactive metabolite monocrotaline pyrrole (MCTP). Incubation of cultured bovine pulmonary arterial endothelial cells (BPAEC) with MCTP results in covalent binding to DNA, cell cycle arrest, and delayed but progressive cell death. The mode of cell death in MCTP-induced endothelial damage has not been addressed previously. Since DNA damage is frequently associated with apoptosis, the presence or absence of apoptosis in adherent BPAEC was determined by several techniques, including morphologic and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling. Two concentrations of MCTP (5 and 34.5 microgram/ml) along with a vehicle control were examined with each assay. Both concentrations of MCTP induced increasing numbers of cells to undergo apoptosis over time beginning as early as 6 h after exposure to MCTP in the high concentration group. Control and vehicle control cells exhibited small amounts of apoptosis (1-2%), which did not change over the duration of the experiment. Additionally, cell membrane integrity was assessed over time by either exposure to membrane-impermeant dyes or measuring LDH release. By either method, BPAEC had increased membrane permeability after about 48 h of either low or high concentration MCTP exposure. We conclude that both a low or high concentration of MCTP causes cell death in BPAEC by inducing apoptosis.
Thomas
H C
HC
Departments of Veterinary Pathology, Microbiology, and Immunology, University of California at Davis, California, USA.
Lamé
M W
MW
Dunston
S K
SK
Segall
H J
HJ
Wilson
D W
DW
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002417:Cattle; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002478:Cells, Cultured; D004253:DNA Nucleotidylexotransferase / Q000187:drug effects / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology; D007770:L-Lactate Dehydrogenase / Q000187:drug effects / Q000378:metabolism; D008856:Microscopy, Fluorescence; D016686:Monocrotaline / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D011651:Pulmonary Artery / Q000187:drug effects*; D013997:Time Factors
C014114:monocrotaline pyrrole; D016686:Monocrotaline; D007770:L-Lactate Dehydrogenase; D004253:DNA Nucleotidylexotransferase