Hypoxia-induced cell death and changes in hypoxia-inducible factor-1 activity in PC12 cells upon exposure to nerve growth factor.
The transcription factor hypoxia-inducible factor-1 (HIF-1) strongly contributes to the expression of adaptive genes under hypoxic conditions. In addition, HIF-1 has been implicated in the regulation of delayed neuronal cell death. Suspension-grown and adherent PC12 cells treated with NGF were used as an experimental model for studying the relationship between hypoxia-induced cell death and activation of HIF-1. Cell damage was assessed by flow cytometry of double-stained (Annexin V and propidiumiodide) cells, and by analysis of the overall death parameters LDH and mitochondrial dehydrogenase. In parallel, cells were transfected with a control and a three-hypoxia-responsive-elements (HRE)-containing vector and HIF-1-driven luciferase activity was determined. Exposure of NGF-treated PC12 cells to hypoxia resulted in a higher cell death rate when compared to untreated controls. PC12 cells exposed for 2 days to NGF exhibited a decrease of HIF-1 activity up to a factor of ten. This decrease may contribute to the enhanced hypoxia-induced cell death via reduced expression of HIF-1alpha-regulated genes responsible for adaptation to hypoxia, like those for glucose transport proteins and enzymes of the glycolytic chain. The decrease in HIF-1 activity and the increase in hypoxia sensitivity may suggest that NGF act as an hierarchically organized signaling molecule.
Department of Neonatology, Charité, Humboldt University, 14057, Berlin, Germany.
Nico
N
Charlier
Norbert
N
Leclere
Ursula
U
Felderhoff
Julia
J
Heldt
Thomas
T
Kietzmann
Michael
M
Obladen
Johann
J
Gross
D000818:Animals; D017304:Annexin A5; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001238:Asphyxia Neonatorum / Q000378:metabolism* / Q000503:physiopathology; D016923:Cell Death / Q000187:drug effects / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002490:Central Nervous System / Q000378:metabolism* / Q000503:physiopathology; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D017930:Genes, Reporter / Q000187:drug effects / Q000502:physiology; D005822:Genetic Vectors / Q000187:drug effects / Q000502:physiology; D006801:Humans; D002534:Hypoxia, Brain / Q000378:metabolism* / Q000503:physiopathology; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007231:Infant, Newborn; D008156:Luciferases / Q000235:genetics; D009336:Necrosis; D020932:Nerve Growth Factor / Q000378:metabolism* / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D016716:PC12 Cells; D010641:Phenotype; D011419:Propidium; D051381:Rats; D014157:Transcription Factors
D017304:Annexin A5; D004268:DNA-Binding Proteins; C497442:HIF1A protein, human; C497444:Hif1a protein, rat; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D014157:Transcription Factors; D011419:Propidium; D020932:Nerve Growth Factor; D008156:Luciferases