Metabolic and genetic analyses of apoptosis in potassium/serum-deprived rat cerebellar granule cells.
Cerebellar granule cells maintained in medium containing serum and 25 mM potassium undergo an apoptotic death within 96 hr when switched to serum-free medium with 5 mM potassium. Because large numbers of apparently homogeneous neurons can be obtained, this represents a potentially useful model of neuronal programmed cell death (PCD). Analysis of the time course and extent of death after removal of either serum or K+ alone demonstrated that a fast-dying (T(1/2) = 4 hr) population (20%) responded to serum deprivation, whereas a slow-dying (T(1/2) = 25 hr) population (80%) died in response to K+ deprivation. Taking advantage of the complete death after removing both K+ and serum, changes in metabolic events and mRNA levels were analyzed in this model. Glucose uptake, protein synthesis, and RNA synthesis fell to <35% of control by 9 hr after potassium/serum deprivation, a time when 85% of the cells were still viable. The pattern of the fall in these metabolic parameters was similar to that reported for trophic factor-deprived sympathetic neurons. Most mRNAs decreased markedly after K+/serum deprivation. Levels of c-jun mRNA increased fivefold in potassium/serum-deprived granule cells; c-jun is required for cell death of sympathetic neurons. mRNA levels of cyclin D1, c-myb, collagenase, and transin remained relatively constant in potassium/serum-deprived granule cells. These data demonstrate the existence of two populations of granule cells with respect to cell death and define common metabolic and genetic events involved in neuronal PCD.
Miller
T M
TM
Department of Neurology and Molecular Biology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Johnson
E M
EM
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D001790:Blood Physiological Phenomena; D002470:Cell Survival; D002478:Cells, Cultured; D002531:Cerebellum / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D016895:Culture Media, Serum-Free / Q000494:pharmacology*; D015870:Gene Expression; D011188:Potassium / Q000494:pharmacology; D011191:Potassium Deficiency / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley
D016895:Culture Media, Serum-Free; D011188:Potassium