Prefrontal TNRC6A mediates anxiety-like behaviour by regulating CRF through the maintenance of miR-21-3p stability

Anxiety is an emotional response to a potential threat. It is characterized by worry, feelings of tension, and physical changes. Trinucleotide repeat containing adaptor 6A (TNRC6A) binds to argonaute (AGO) proteins and microRNAs to form the miRNA-induced silencing complex (miRISC), which mediates mRNA degradation, storage, and translational repression functions. However, whether TNRC6A is involved in anxiety regulation remains unknown.

In this study, TNRC6A was downregulated in the prefrontal cortex (PFC) of mice exposed to acute restraint stress. Inhibition of TNRC6A in PFC induced anxious behaviour. RNA immunoprecipitation, RNA pull-down and real-time quantitative PCR revealed that TNRC6A directly binds to miR-21-3p and maintains its stability. Intriguingly, miR-21-3p was downregulated in the PFC of acute stress mice, whereas overexpression of miR-21-3p significantly reduced anxiety-like behaviour. Furthermore, miR-21-3p knockdown significantly increased the frequency and amplitude of spontaneous excitatory postsynaptic currents (sEPSCs) in the PFC pyramidal neurons. Dual luciferase assay and western blotting confirmed that miR-21-3p binds to the 3 ‘UTR region of corticotropin-releasing factor (CRF) mRNA and regulates CRF and cAMP-response element binding protein (CREB) expression. These results confirm that low levels of TNRC6A in the PFC decrease the stability of miR-21-3p which promotes the up-regulation of CRF, leading to the development of anxiety-like behaviours. This research provides insight into a novel molecular mechanism by which TNRC6A regulates anxiety behaviour through the miR-21-3p/CRF signalling axis.