MicroRNA-Mediated Therapy Modulating Blood-Brain Barrier Disruption Improves Vascular Cognitive Impairment.

There are currently no effective treatments for the prevention of dementia associated with vascular cognitive impairment. MicroRNAs regulate gene expression at the post-transcriptional level and play key roles in vascular disorders. TNFα (tumor necrosis factor-α) regulates blood-brain barrier breakdown through modification of cerebral tight junctions. Here, we sought key TNFα-responsive microRNAs that might influence blood-brain barrier breakdown via cerebral tight junction disruption in vascular cognitive impairment. Using a mouse model of vascular cognitive impairment, chronic cerebral hypoperfusion within the white matter was induced with bilateral common carotid artery stenosis (BCAS) surgery. TNFα gene expression was increased in white matter post-BCAS surgery, and TNFα stimulation decreased claudin-5, ZO-1 (tight-junction protein 1), and occludin gene expression in murine brain endothelial cells. In silico analysis predicted 8 candidate microRNAs as regulators of claudin-5, ZO-1, and occludin gene expression. Of these, only miR-501-3p was upregulated by TNFα in vitro and was upregulated in the white matter after BCAS surgery. Further, miR-501-3p directly bound to the 3'-untranslated region of human ZO-1 and downregulated transendothelial electric resistance. In vivo administration of a locked nucleic acid -modified antisense oligonucleotide versus miR-501-3p suppressed BCAS-induced reduction of ZO-1 gene expression and blood-brain barrier disruption within the white matter and significantly ameliorated working memory deficits after BCAS surgery. We here provide the first evidence that the TNFα-miR-501-3p-ZO-1 axis plays an important role in the pathogenesis of cerebral hypoperfusion-induced working memory deficits and white matter lesions, as a result of blood-brain barrier breakdown via tight junction disruption. Therapeutic manipulation of miR-501-3p holds promise for limiting vascular cognitive impairment progression.