# AAV‐Driven miR‐146a Promotes Neurite Outgrowth and Axonal Regeneration in Cortical Neurons

## TL;DR

This study shows that using AAV to deliver miR-146a can boost nerve regeneration in rat brain neurons, offering hope for CNS injury recovery.

## Contribution

The study demonstrates that AAV-mediated miR-146a overexpression promotes axonal regeneration in CNS neurons.

## Key findings

- AAV.miR-146a significantly increases neurite outgrowth and branching in rat cortical neurons.
- Axonal regeneration is strongly enhanced by AAV.miR-146a after injury.
- TRAF6 is a key target of miR-146a, with its expression reduced by AAV.miR-146a.

## Abstract

Adult central nervous system (CNS) neurons exhibit limited intrinsic regenerative capacity, contributing to poor recovery after injury. MicroRNAs (miRNAs) have emerged as key regulators of many biological processes, yet their therapeutic potential in CNS repair remains incompletely understood. Here, we investigated whether adeno‐associated virus (AAV) vector‐mediated overexpression of miR‐146a enhances neurite and axon regeneration in primary cortical neurons from Wistar rats. We found that AAV.miR‐146a significantly increased neurite outgrowth, branching, and long‐distance neurite regeneration following scratch injury. Using a microfluidic platform that allows us to selectively lesion axons, we further demonstrated that AAV.miR‐146a robustly promotes axonal regrowth. Bioinformatic analyses revealed enrichment of miR‐146a target genes involved in transcriptional regulation and synaptic function, with the inflammatory adaptor TRAF6 emerging as a key predicted target. Consistent with these predictions, AAV.miR‐146a markedly reduced TRAF6 expression. Together, our results identify miR‐146a as a promising therapeutic candidate for enhancing CNS axonal repair and highlight TRAF6 signaling as a potential mechanistic link to its regenerative effects.

In the adult central nervous system (CNS), neuronal regeneration after injury is limited, resulting in poor functional recovery. MicroRNAs (miRNAs), a class of small noncoding RNAs that control gene expression, have gained attention as potential therapeutic agents, although their contribution to CNS repair remains insufficiently understood. In this study, we demonstrate that adeno‐associated virus (AAV)‐mediated expression of miR‐146a (AAV.miR‐146a) significantly increases neurite extension and branching compared with a control AAV vector (AAV.CTRL) in uninjured rat cortical neurons. Moreover, after axonal damage, AAV.miR‐146a strongly enhances axon regeneration. Collectively, these results highlight miR‐146a as a promising molecular target to boost the regenerative capacity of CNS neurons.