CAFFEINE PROTECTS AGAINST LY294002-INDUCED APOPTOSIS IN CEREBELLAR GRANULE NEURONS

AIM: To study the protection of caffeine against LY294002-induced apoptosis in cerebellar granule neurons. METHODS: Primarily cultured cerebellar granule neurons were induced to apoptosis by LY294002. Agarose gel electrophoresis was used to analyse DNA fragmentation of the apoptotic neurons. Intracellular Ca²⁺ was measured by using Fura-2/AM fluorescent technology. Analysis of phosphorylated c-Jun was carried out by means of immunofluorometry. The measurement of c -Jun content and JNK activity was performed with Western blot method. RESULTS: Caffeine was shown to prevent cultured cerebellar granule neurons from apoptosis induced by LY294002, a specific inhibitor of PI-3-K, in a dose dependent manner. The protection of caffeine on neurons was not dependent on the elevation of Ca²⁺i, nor on the biological activity of intracellular cAMP. Caffeine decreased the activity of JNK and the levels of c-Jun and phospho c-Jun in cerebellar granule neurons. CONCLUSION: Caffeine prevents cerebellar granule neurons from LY294002 induced apoptosis by inhibiting the activity of JNK and blocking the phosphorylation of c-Jun.