MicroRNA-153 impairs hippocampal synaptic vesicle trafficking via downregulation of synapsin I in rats following chronic cerebral hypoperfusion.

Chronic cerebral hypoperfusion (CCH) promotes the development of Alzheimer's pathology. However, whether and how CCH impairs the synaptic vesicle trafficking is still unclear. In the present study, we found that the hippocampal glutamatergic vesicle trafficking was impaired as indicated by a significant shortened delayed response enhancement (DRE) phase in CA3-CA1 circuit and decreased synapsin I in CCH rats suffering from bilateral common carotid artery occlusion (2VO). Further study showed an upregulated miR-153 in the hippocampus of 2VO rats. In vitro, overexpression of miR-153 downregulated synapsin I by binding the 3'UTRs of SYN1 mRNAs, which was prevented by its antisense AMO-153 and miRNA-masking antisense oligodeoxynucleotides (SYN1-ODN). In vivo, the upregulation of miR-153 elicited similar reduced DRE phase and synapsin I deficiency as CCH. Furthermore, miR-153 knockdown rescued the downregulated synapsin I and shortened DRE phase in 2VO rats. Our results demonstrate that CCH impairs hippocampal glutamatergic vesicle trafficking by upregulating miR-153, which suppresses the expression of synapsin I at the post-transcriptional level. These results will provide important references for drug research and treatment of vascular dementia.