Antisense oligonucleotides targeting basal forebrain ATXN2 enhances spatial memory and ameliorates sleep deprivation‐induced fear memory impairment in mice

INTRODUCTION: Regulation of brain‐derived neurotrophic factor (BDNF) in the basal forebrain ameliorates sleep deprivation‐induced fear memory impairments in rodents. Antisense oligonucleotides (ASOs) targeting ATXN2 was a potential therapy for spinocerebellar ataxia, whose pathogenic mechanism associates with reduced BDNF expression. We tested the hypothesis that ASO7 targeting ATXN2 could affect BDNF levels in mouse basal forebrain and ameliorate sleep deprivation‐induced fear memory impairments. METHODS: Adult male C57BL/6 mice were used to evaluate the effects of ASO7 targeting ATXN2 microinjected into the bilateral basal forebrain (1 μg, 0.5 μL, each side) on spatial memory, fear memory and sleep deprivation‐induced fear memory impairments. Spatial memory and fear memory were detected by the Morris water maze and step‐down inhibitory avoidance test, respectively. Immunohistochemistry, RT‐PCR, and Western blot were used to evaluate the changes of levels of BDNF, ATXN2, and postsynaptic density 95 (PSD95) protein as well as ATXN2 mRNA. The morphological changes in neurons in the hippocampal CA1 region were detected by HE staining and Nissl staining. RESULTS: ASO7 targeting ATXN2 microinjected into the basal forebrain could suppress ATXN2 mRNA and protein expression for more than 1 month and enhance spatial memory but not fear memory in mice. BDNF mRNA and protein expression in basal forebrain and hippocampus was increased by ASO7. Moreover, PSD95 expression and synapse formation were increased in the hippocampus. Furthermore, ASO7 microinjected into the basal forebrain increased BDNF and PSD95 protein expression in the basal forebrain of sleep‐deprived mice and counteracted sleep deprivation‐induced fear memory impairments. CONCLUSION: ASOs targeting ATXN2 may provide effective interventions for sleep deprivation‐induced cognitive impairments.