Extracellular calcium deprivation in astrocytes: Regulation of mRNA expression and apoptosis

Roberto Chiesa, Nadia Angeretti, Roberto Del Bo, Elisa Lucca, Elettra Munna, Gianluigi Forloni

Research output: Contribution to journalArticlepeer-review


Cell viability and gene expression were studied in primary astroglial cells cultured in a nominally calcium-free medium. Ca2+ deprivation reduced progressively the astrocytes' viability, starting from 12 h; the restoration of a normal Ca2+ concentration (1.8 mM) in the medium after 12-h deprivation reversed the degenerative effect within 24 h. Biochemical and morphological examinations indicated that cell death induced by Ca2+ 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 Ca2+ deprivation. Furthermore, shifting to a Ca2+-free medium modified the expression of Ich-1s transcript and rapidly increased intracellular cyclic AMP, which has been implicated in the transcriptional activation of immediate-early genes. The absence of Ca2+ 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 Ca2+ deprivation, when the effect on cell viability was negligible. When Ca2+ deprivation was prolonged for 24 h the expression of mRNA dropped completely, and restoration of the Ca2+ 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 influx but also with the Ca2+ extracellular Ca deprivation.

Original languageEnglish
Pages (from-to)1474-1483
Number of pages10
JournalJournal of Neurochemistry
Issue number4
Publication statusPublished - Apr 1998


  • Apoptosis
  • Ca deprivation
  • Calcium-free medium
  • Cell death
  • Cell viability
  • Constitutive proteins
  • Gene expression

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience


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