Rotenone-induced caspase 9/3-independent and -dependent cell death in undifferentiated and differentiated human neural stem cells.
We used human neural stem cells (hNSCs) and their differentiated cultures as a model system to evaluate the mechanism(s) involved in rotenone (RO)- and camptothecin (CA)-induced cytotoxicity. Results from ultrastructural damage and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining indicated that RO-induced cytotoxicity resembled CA-induced apoptosis more than H(2)O(2)-induced necrosis. However, unlike CA-induced, caspase 9/3-dependent apoptosis, there was no increased activity in caspase 9, caspase 3 or poly (ADP-ribose) polymerase (PARP) cleavage in RO-induced cytotoxicity, in spite of time-dependent release of cytochrome c and apoptosis-inducing factor (AIF) following mitochondrial membrane depolarization and a significant increase in reactive oxygen species generation. Equal doses of RO and CA used in hNSCs induced caspase 9/3-dependent apoptosis in differentiated cultures. Time-dependent ATP depletion occurred earlier and to a greater extent in RO-treated hNSCs than in CA-treated hNSCs, or differentiated cultures treated with RO or CA. In conclusion, these results represent a unique ultrastructural and molecular characterization of RO- and CA-induced cytotoxicity in hNSCs and their differentiated cultures. Intracellular ATP levels may play an important role in determining whether neural progenitors or their differentiated cells follow a caspase 9/3-dependent or -independent pathway in response to acute insults from neuronal toxicants.
Li
Jiang
J
School of Pharmacy, University of Wisconsin at Madison, 777 Highland Avenue, Madison, WI 53705-2222, USA.
Spletter
Maria L
ML
Johnson
Delinda A
DA
Wright
Lynda S
LS
Svendsen
Clive N
CN
Johnson
Jeffrey A
JA
D000255:Adenosine Triphosphate / Q000378:metabolism; D002166:Camptothecin / Q000633:toxicity; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects; D002454:Cell Differentiation; D002478:Cells, Cultured; D053938:DNA Fragmentation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000633:toxicity; D006801:Humans; D020287:In Situ Nick-End Labeling; D008954:Models, Biological; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012402:Rotenone / Q000633:toxicity*; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D059004:Topoisomerase I Inhibitors; D014475:Uncoupling Agents / Q000633:toxicity
D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; D059004:Topoisomerase I Inhibitors; D014475:Uncoupling Agents; D012402:Rotenone; D000255:Adenosine Triphosphate; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases; D002166:Camptothecin