Role of mitochondrial dysfunction in S-(1,2-dichlorovinyl)-l-cysteine-induced apoptosis.
The nephrotoxicity of trichloroethylene and dichloroacetylene has previously been linked to mitochondrial dysfunction induced by the metabolite S-(1,2-dichlorovinyl)-l-cysteine (DCVC). In this study, we examined whether key biochemical steps associated with mitochondria occur in DCVC-induced apoptosis in cultured porcine proximal tubular LLC-PK1 cells. DCVC caused a decrease in mitochondrial membrane potential (mt Delta Psi) beginning at 4 h and a release of cytochrome c into the cytoplasm at 6 h. Caspase-3-like activity was detected at 6 h and extensive DNA fragmentation was observed at 8 h. Decreases in cellular ATP were not evident until 8 h and later, even though electron microscopy showed that the mitochondria were extensively swollen. Aminooxyacetic acid (AOAA), an inhibitor of cysteine-conjugate beta-lyase, protected against mitochondrial changes and apoptosis. Overexpression of the antiapoptotic Bcl-2 protein desensitized LLC-PK1 cells to DCVC-induced apoptosis. These results support the interpretation that mitochondrial release of cyt c and cyt c-dependent activation of caspase-3 could have a central role in nephrotoxicity due to haloalkene-derived cysteine S-conjugates.
Chen
Y
Y
Program of Biochemistry, Cell Biology and Developmental Biology, Emory University, Atlanta, Georgia 30322, USA.
Cai
J
J
Anders
M W
MW
Stevens
J L
JL
Jones
D P
DP
D000625:Aminooxyacetic Acid / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D003545:Cysteine / Q000031:analogs & derivatives* / Q000633:toxicity*; D003574:Cytochrome c Group / Q000378:metabolism; D053938:DNA Fragmentation; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D007425:Intracellular Membranes / Q000737:chemistry / Q000187:drug effects; D007687:Kidney Tubules, Proximal / Q000187:drug effects* / Q000648:ultrastructure; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D023421:Models, Animal; D013552:Swine
D003574:Cytochrome c Group; D004791:Enzyme Inhibitors; D000625:Aminooxyacetic Acid; C039961:S-(1,2-dichlorovinyl)cysteine; D020169:Caspases; D003545:Cysteine