Search

Aims: Stroke has a high incidence and is a disabling condition that can lead to severe cognitive, motor, and sensory dysfunction. In this study, we employed a drug repurposing strategy to investigate the neuroprotective effect of lomitapide on focal ischemic brain injury and explore its potential mechanism of action. Methods: Experimental cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in adult male C57BL/6 mice and simulated by oxygen–glucose deprivation in N2a‐BV2 cells in co‐cultivation. Results: Lomitapide significantly increased the survival rate, reduced the neuronal tissue loss, and improved the neurological function after MCAO. Furthermore, lomitapide could increase the expression of LC3‐II, reduce the expression of P62 and LAMP2, promote autophagic flux, and inhibit apoptosis by increasing and inhibiting the expression of the apoptosis‐associated proteins Bcl‐2 and Bax, respectively. In addition, lomitapide inhibited the migration of pro‐inflammatory microglia. Conclusion: Lomitapide is a lipid‐lowering drug, and this is the first study to explore its protective effect on ischemic nerve injury in vitro and in vivo. Our results suggest that lomitapide can be repositioned as a potential therapeutic drug for the treatment of stroke. [ABSTRACT FROM AUTHOR]

Global DNA and histone methylation patterns in astrocytes following ischemia are influenced by age; however, it is unknown whether aberrant methylation can induce reactive astrogliosis after ischemic stroke in elderly rodents. Here we showed that phosphorylated signal transducer and activator of transcription 3 (STAT3) level increased along with that of the astrogliosis marker glial fibrillary acidic protein (GFAP) on days 1, 3, and 14 post‐reperfusion in 9‐month‐old male mice with middle cerebral artery occlusion (MCAO). Methylation of the STAT3 binding site in the GFAP gene promoter was increased in these mice on days 3 and 14 postreperfusion. The repressive modification histone 3 lysine 27 trimethylation (H3K27me3) was decreased, whereas the permissive modification histone 3 lysine 4 trimethylation was increased in GFAP‐positive cells in the ipsilateral cortex. Furthermore, DNA methyltransferase 1 (DNMT1) expression in astrocytes was upregulated in the ischemic brain. In primary astrocyte cultures, the microRNA miR‐424 was found to target nuclear factor IA (NFIA); miR‐424 agomir increased DNMT1 and H3K27me3 levels in U87 cells subjected to oxygen and glucose deprivation and induced cell cycle arrest in primary astrocytes while suppressing reactive astrocytosis, thereby preserving the structure of neurons and their axons in MCAO mice. These results demonstrate that miR‐424 prevents astrogliosis following cerebral ischemia/reperfusion in elderly mice by enhancing H3K27me3 via NFIA/DNMT1 signaling. [ABSTRACT FROM AUTHOR]