Genomic and physiological analysis of oxygen sensitivity and hypoxia tolerance in PC12 cells.
The mechanisms by which cells adapt and respond to changes in oxygen tension remain largely unknown. Our laboratory has used the PC12 cell line to study both biophysical and molecular responses to hypoxia. This chapter summarizes our findings. We found that membrane depolarization that occurred when PC12 cells were exposed to reduced O(2) was mediated by a specific potassium channel, the Kv1.2 channel. The membrane depolarization leads to increased Ca(2+) conductance through a voltage-sensitive channel, which in turn mediates the release of the neurotransmitters dopamine, adenosine, glutamate, and GABA. In addition, increased intracellular Ca(2+) and other signaling systems regulate hypoxia-induced gene expression, which contributes to the adaptive response to reduced O(2+). We identified several critical signaling pathways that regulate a complex gene expression profile in PC12 cells during hypoxia. These include the cAMP-protein kinase A, Ca(2+)-calmodulin, p42/44 mitogen-activated protein kinase (MAPK), stress-activated protein kinase (SAPK; p38 kinase), and the phosphatidylinositol 3-kinase-AKT as regulators of gene expression. Several of these pathways regulate hypoxia-specific transcription factors that are members of the hypoxia-inducible factor (HIF) family. Recently, we have successfully used subtractive cDNA libraries and microarray analysis to identify the genomic profile that mediates the cellular response to hypoxia.
Seta
Karen
K
Genome Research Institute and Department of Genome Science, University of Cincinnati, Cincinnati, Ohio 45267-0505, USA.
Kim
Hie-Won
HW
Ferguson
Tsuneo
T
Kim
Richard
R
Pathrose
Peterson
P
Yuan
Yong
Y
Lu
Gang
G
Spicer
Zachary
Z
Millhorn
David E
DE
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism / Q000502:physiology; D018076:DNA, Complementary / Q000378:metabolism; D015723:Gene Library; D000860:Hypoxia / Q000378:metabolism; D015151:Immunoblotting; D007477:Ions; D008156:Luciferases / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008564:Membrane Potentials; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010100:Oxygen / Q000378:metabolism*; D016716:PC12 Cells; D051381:Rats; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases
D018076:DNA, Complementary; D007477:Ions; D008156:Luciferases; D019950:Mitogen-Activated Protein Kinase 1; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D010100:Oxygen; D002118:Calcium