The integrated stress response (ISR) has been implicated in cognitive decline associated with ageing and neurodegenerative diseases. Pharmacological inhibition of the ISR using the small-molecule ISRI Show more
The integrated stress response (ISR) has been implicated in cognitive decline associated with ageing and neurodegenerative diseases. Pharmacological inhibition of the ISR using the small-molecule ISRIB has demonstrated promising neuroprotective effects in several preclinical models. However, its potential therapeutic value in vascular cognitive impairment (VCI) remains largely unexplored. Here, we established a modified permanent bilateral carotid occlusion (2-VO) rat model of VCI and investigated the therapeutic potential of the ISRIB via microinjection in hippocampal dentate gyrus (DG). VCI rats exhibited elevated expression of vascular endothelial growth factor (VEGF), cluster of differentiation 34 (CD34), ionized calcium-binding adapter molecule 1 (Iba1), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6), indicating successful establishment of the model. Behavioral assessments revealed that VCI rats exhibited impaired spatial, working, and recognition memory. Bioinformatic analysis highlighted ISR pathway activation in VCI. Furthermore, elevated phosphorylated eukaryotic initiation factor 2 alpha (p-eIF2α) and activating transcription factor 4 (ATF4) protein levels in the DG confirmed ISR activation in the DG of VCI rats. VCI also reduced neuronal integrity, as evidenced by decreased Nissl body density. ISRIB treatment significantly improved cognitive performance, suppressed ATF4 expression, enhanced puromycin-labeled protein synthesis, and restored phosphorylated cAMP response element-binding protein (p-CREB) and brain-derived neurotrophic factor (BDNF) signaling. Notably, ISRIB increased c-fos activation and upregulated synaptophysin and postsynaptic density protein 95 (PSD95) expression in the DG of VCI rats, indicating enhanced neuronal activity and synaptic function. Our results indicate that ISR activation contributes to hippocampal-dependent memory impairment in VCI. ISRIB effectively restores synaptic function and cognition, underscoring its therapeutic value and translational potential in treating VCI. Show less