A Decoy Oligodeoxynucleotides Disturbing Forkhead Box O3 Mediated ctnna2 Transcriptional Repression Prevents...

Perioperative cognitive disorder (PND) affects up to 31% of surgical patients. Although clinical studies have identified a variety of risk factors, no effective prevention has been developed. From our previous cohort of PND patients, several single-nucleotide polymorphism (SNP) sites on ctnna2 were identified. The current study aims to decipher the role and regulatory mechanism of ctnna2 in the PND model and to develop decoy oligodeoxynucleotides (decoy) for the possible prevention of PND.

Both mice model (exploratory laparotomy+isoflurane) and the neuronal model (TNFα+isoflurane, T + I) for PND were used. Bioinformatic research was utilized to identify transcriptive active areas on ctnna2, foxo3 sequence, and to predict possible transcriptional factors for regulation. Molecular biological techniques were used to decipher the regulatory mechanism and specific sites of the Sirt1-foxo3-ctnna2 axis in the development of PND. Finally, an decoy targeting the Foxo3-ctnna2 interaction was designed and tested for effectiveness in PND.

Our results showed that the SNP rs12472215 is located at a newly defined enhancer region within the ctnna2 intron that can be regulated by Foxo3 in the human genome. The rs12472215 A>T mutation potentiates Foxo3's transcriptive inhibitory effect on ctnna2. Experimental laparotomy in mice revealed that hippocampal Foxo3 upregulation and α-N-catenin reduction are involved in PND development. ChIP-PCR deciphered two regulatory sites (R1 and R2) of Foxo3 on ctnna2 in the mice that are strengthened by T + I. siAscl1 abolished the rescue effect of carbenoxolone (CBX, Foxo3-specific inhibitor) on α-N-catenin expression in the T + I model, indicating that Foxo3 inhibits ctnna2 transcription indirectly through Ascl1. Reduction of Sirt1 increased acetyl-Foxo3, which enhanced its stability in PND. Sirt1 activation reduced Foxo3 expression, acetyl-Foxo3 level, and rescued α-N-catenin expression in T + I stimulated neurons. More importantly, the new decoy disturbing Foxo3-ctnna2 interaction effectively prevents α-N-catenin reduction, CA1 pyramidal neuron morphological change, electrophysiological dysfunction, and improves cognitive deficit in PND mice.

These results provided a new revenue for identifying targets and developing interventions for PND. The decoy, due to its specificity and short acting time, merits further exploration for possible clinical use.