The endoplasmic reticulum-related events in S-nitrosoglutathione-induced neurotoxicity in cerebellar granule cells.

Nitric oxide (NO)-induced neurotoxicities are involved in the pathogenesis of several neurodegenerative disorders featured by misfolded proteins. However, the details remain to be investigated. In the present work, we focus on the study of some endoplasmic reticulum-related events in S-nitrosoglutathione (GSNO)-induced neurotoxicity in cerebellar granule cells (CGCs) and we demonstrated that: (1) GSNO caused sustained elevation of intracellular calcium; (2) This calcium elevation resulted partially from the depletion of endoplasmic reticulum (ER) calcium stores; (3) There was ER stress which was indicated by the incomplete splicing of X-box binding protein (XBP-1) mRNA by 8-polysialyltransferase (Pst1); (4) GSNO upregulated the expression of the proapoptotic growth arrest and DNA damage-inducible gene (Gadd153) and caused the depletion of intracellular glutathione (GSH) pools. At the same time, GSNO downregulated the expression of the antiapoptotic gene Sarco/endoplasmic reticulum calcium-ATPase (SERCA2b) in parallel with the downregulation of the antiapoptotic ER chaperones-glucose-regulated protein genes (Grp78 and Grp94). These effects indicate that ER is one of the NO targets in GSNO-induced neurotoxicity in cerebellar granule cells besides mitochondria.