HSP70 induction and oxidative stress protection mediated by a subtoxic dose of NMDA in the retinoic acid-differentiated C6 glioma cell line.
NMDA class of glutamate receptors plays an important role in regulating toxic and plastic responses in CNS. Astrocytes are the predominant cell type in the adult CNS and recent studies have suggested their role in many aspects of CNS function and dysfunction. We report here the protective effect of a subtoxic dose of NMDA in retinoic acid differentiated C6 glioma cell cultures. C6 glioma cell cultures differentiated with retinoic acid (10 microM) were exposed to NMDA (100 microM) or to antagonist MK-801 (200 nM) alone as well as with NMDA and cells were harvested after 24h of treatment to study the expression of HSP70 and for biochemical assay of free radical scavenger system. The protection imparted by a subtoxic dose of NMDA was checked by challenging the differentiated controls as well as NMDA treated and MK-801 treated cultures with a toxic dose of glutamate and subsequently estimating the free radical scavenger system profile. Biochemical analysis revealed a significant increase in the activities of glutathione peroxidase (GPx), copper zinc-superoxide dismutase (CuZnSOD) and reduced glutathione (GSH) content upon exposure to NMDA. No significant change was observed in the level of lipid peroxidation (LPx). A significant increase was observed in HSP70 expression as seen by Western blotting and immunocytofluorescent studies in NMDA treated cultures. Treatment of cultures with MK-801 alone, a non-competitive NMDA receptor antagonist, or pretreatment with MK-801 prior to NMDA exposure prevented the NMDA mediated changes indicating the involvement of NMDA receptors mediated mechanism. The results illustrate the protective effect of a subtoxic dose of NMDA in RA differentiated C6 glioma cell line.
Singh
Jaspreet
J
Department of Biotechnology, Guru Nanak Dev University, Amritsar, Punjab 143005, India.
Kaur
Gurcharan
G
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015153:Blotting, Western; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D002470:Cell Survival; D019610:Cytoprotection / Q000187:drug effects / Q000502:physiology*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D005910:Glioma / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000187:drug effects* / Q000378:metabolism; D016202:N-Methylaspartate / Q000494:pharmacology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology
D018691:Excitatory Amino Acid Antagonists; D018840:HSP70 Heat-Shock Proteins; D018696:Neuroprotective Agents; D016194:Receptors, N-Methyl-D-Aspartate; D014212:Tretinoin; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate