In:
Journal of Neurochemistry, Wiley, Vol. 70, No. 4 ( 1998-04), p. 1474-1483
Abstract:
Abstract: Cell viability and gene expression were studied in primary astroglial cells cultured in a nominally calcium‐free medium. Ca 2+ deprivation reduced progressively the astrocytes' viability, starting from 12 h; the restoration of a normal Ca 2+ concentration (1.8 m M ) in the medium after 12‐h deprivation reversed the degenerative effect within 24 h. Biochemical and morphological examinations indicated that cell death induced by Ca 2+ deprivation was mediated by apoptosis. This was associated with the expression of c‐ fos , c‐ jun , and c‐ myc , which, with different time courses, were induced in astrocytes after Ca 2+ deprivation. Furthermore, shifting to a Ca 2+ ‐free medium modified the expression of Ich‐1 S transcript and rapidly increased intracellular cyclic AMP, which has been implicated in the transcriptional activation of immediate‐early genes. The absence of Ca 2+ in the medium reduced the expression of constitutive proteins such as α‐actin, clusterin, glial fibrillary acidic protein, amyloid precursor protein, and glucose‐6‐phosphate dehydrogenase. The expression of these mRNAs was reduced 〉 50% after 8 h of Ca 2+ deprivation, when the effect on cell viability was negligible. When Ca 2+ deprivation was prolonged for 24 h the expression of mRNA dropped completely, and restoration of the Ca 2+ ions in the medium for 48 h did not reverse this effect. In contrast with general assumption, the apoptotic machinery in astrocytes is activated similarly not only by increased Ca 2+ influx but also with the extracellular Ca 2+ deprivation.
Type of Medium:
Online Resource
ISSN:
0022-3042
,
1471-4159
DOI:
10.1046/j.1471-4159.1998.70041474.x
Language:
English
Publisher:
Wiley
Publication Date:
1998
detail.hit.zdb_id:
80158-6
detail.hit.zdb_id:
2020528-4
SSG:
12
