Microcystin-RR induced apoptosis in tobacco BY-2 suspension cells is mediated by reactive oxygen species and mitochondrial permeability transition pore status.
When tobacco BY-2 cells were treated with 60 microg/mL MC-RR for 5d, time-dependent effects of MC-RR on the cells were observed. Morphological changes such as abnormal elongation, evident chromatin condensation and margination, fragmentation of nucleus and formation of apoptotic-like bodies suggest that 60 microg/mL MC-RR induced rapid apoptosis in tobacco BY-2 cells. Moreover, there was a significant and rapid increase of ROS level before the loss of mitochondrial membrane potential (DeltaPsi(m)) and the onset of cell apoptosis. Ascorbic acid (AsA), a major primary antioxidant, prevented the increase of ROS generation, blocked the decrease in DeltaPsi(m) and subsequent cell apoptosis, indicating a critical role of ROS in serving as an important signaling molecule by causing a reduction of DeltaPsi(m) and MC-RR-induced tobacco BY-2 cell apoptosis. In addition, a specific mitochondrial permeability transition pores (PTP) inhibitor, cyclosporin A (CsA), significantly blocked the MC-RR-induced ROS formation, loss of DeltaPsi(m), as well as cell apoptosis when the cells were MC-RR stressed for 3d, suggesting that PTP is involved in 60 microg/mL MC-RR-induced tobacco cell apoptosis signalling process. Thus, we concluded that the mechanism of MC-RR-induced apoptosis signalling pathways in tobacco BY-2 cells involves not only the excess generation of ROS and oxidative stress, but also the opening of PTP inducing loss of mitochondrial membrane potential.
Huang
Wenmin
W
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072, PR China.
Xing
Wei
W
Li
Dunhai
D
Liu
Yongding
Y
D017209:Apoptosis / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002478:Cells, Cultured; D005456:Fluorescent Dyes; D008387:Marine Toxins; D052998:Microcystins / Q000633:toxicity*; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism*; D010539:Permeability / Q000187:drug effects; D011523:Protoplasts / Q000187:drug effects / Q000648:ultrastructure; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020112:Rhodamine 123; D013997:Time Factors; D014026:Nicotiana / Q000166:cytology* / Q000648:ultrastructure
D005456:Fluorescent Dyes; D008387:Marine Toxins; D052998:Microcystins; D017382:Reactive Oxygen Species; D020112:Rhodamine 123; C063855:microcystin RR