Novel mechanism of increased Ca ²⁺ release following oxidative stress in neuronal cells involves type 2 inositol-1,4,5-trisphosphate receptors

Dysregulation of Ca ²⁺ signaling following oxidative stress is an important pathophysiological mechanism of many chronic neurodegenerative disorders, including Alzheimer's disease, age-related macular degeneration, glaucomatous and diabetic retinopathies. However, the underlying mechanisms of disturbed intracellular Ca ²⁺ signaling remain largely unknown. We here describe a novel mechanism for increased intracellular Ca ²⁺ release following oxidative stress in a neuronal cell line. Using an experimental approach that included quantitative polymerase chain reaction, quantitative immunoblotting, microfluorimetry and the optical imaging of intracellular Ca ²⁺ release, we show that sub-lethal tert-butyl hydroperoxide-mediated oxidative stress result in a selective up-regulation of type-2 inositol-1,4,5,-trisphophate receptors. This oxidative stress mediated change was detected both at the transcriptional and translational level and functionally resulted in increased Ca ²⁺ release into the nucleoplasm from the membranes of the nuclear envelope at a given receptor-specific stimulus. Our data describe a novel source of Ca ²⁺ dysregulation induced by oxidative stress with potential relevance for differential subcellular Ca ²⁺ signaling specifically within the nucleus and the development of novel neuroprotective strategies in neurodegenerative disorders.