Possible involvement of pyruvate kinase in acquisition of tolerance to hypoxic stress in glial cells.
Neurons are highly vulnerable to ischemic/hypoxic stress, while glial cells show tolerance to such stress. However, the mechanisms for tolerance acquisition in glial cells have yet to be established. We attempted to isolate and identify a stress protein that is upregulated in response to hypoxia in human astrocytoma CCF-STTG1 cells. In particular, pyruvate kinase (PK) was upregulated by hypoxia in CCF-STTG1 cells. Hypoxia-inducible factor 1 (HIF-1), the primary transcription factor that is responsible for multiple gene activation under hypoxia, plays a critical role in PK expression during hypoxic challenge. To determine whether newly synthesized PK is involved in tolerance to hypoxic stress, we established the PK-overexpressing neuronal cells. Overexpression of the wild-type, but not the kinase-negative mutant, resulted in attenuation of the loss of cell viability and the typical apoptotic features by hypoxia or oxidative stress in SK-N-MC cells. These findings suggest that upregulation of PK may result in acquisition of tolerance against hypoxic stress, and that the antioxidant effect may be involved in the protective effect of PK.
Shimizu
Takahiro
T
Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Uehara
Takashi
T
Nomura
Yasuyuki
Y
D016587:Antimutagenic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology; D001254:Astrocytoma; D015153:Blotting, Western / Q000379:methods; D015687:Cell Hypoxia / Q000502:physiology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000502:physiology; D003035:Cobalt / Q000494:pharmacology; D003676:Deferoxamine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007502:Iron Chelating Agents / Q000494:pharmacology; D016296:Mutagenesis / Q000187:drug effects / Q000502:physiology; D009457:Neuroglia / Q000187:drug effects / Q000378:metabolism*; D018384:Oxidative Stress; D011770:Pyruvate Kinase / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D020539:Sequence Analysis, Protein / Q000379:methods; D013312:Stress, Physiological / Q000378:metabolism / Q000473:pathology*; D013997:Time Factors; D015533:Transcriptional Activation; D014162:Transfection / Q000379:methods; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism
D016587:Antimutagenic Agents; D007502:Iron Chelating Agents; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D003035:Cobalt; D006861:Hydrogen Peroxide; D011770:Pyruvate Kinase; C018021:cobaltous chloride; D003676:Deferoxamine