# CREB5 Inhibits Neuronal Ferroptosis via Transactivating ApoL6 to Regulate Lipid Droplet Metabolism After Spinal Cord Injury

## TL;DR

This study shows that CREB5 helps protect neurons after spinal cord injury by regulating lipid metabolism and reducing cell death, which could lead to new treatments.

## Contribution

The study reveals a novel mechanism by which CREB5 inhibits neuronal ferroptosis through transactivation of ApoL6 after spinal cord injury.

## Key findings

- CREB5 enhances ApoL6 transcription to inhibit lipid droplet breakdown and reduce ferroptosis.
- CREB5 knockdown worsens neuronal death and axonal growth in vitro and in vivo.
- ApoL6 overexpression partially reverses the negative effects of CREB5 knockdown.

## Abstract

After spinal cord injury (SCI), neuronal lipid peroxidation and excessive production of reactive oxygen species (ROS) induced by secondary injury exacerbate ferroptosis, impeding regenerative repair and functional recovery in mice. Thus, clarifying the molecular and cellular mechanisms underlying the inhibition of neuronal ferroptosis post‐SCI is crucial.

Single‐cell RNA sequencing (scRNA‐seq) and single‐cell assay for transposase‐accessible chromatin sequencing (scATAC‐seq) were used to analyze changes in the transcription factor CREB5 post‐SCI. Combined with in vitro (primary neuron experiments) and in vivo (mouse SCI model) studies, CREB5 was knocked down/overexpressed, and ApoL6 was overexpressed. Indicators related to neuronal ferroptosis (ROS, lipid peroxidation, free fatty acids, etc.) and functional recovery in mice were detected.

After SCI, the transcriptional activity of the transcription factor CREB5 is enhanced, and its expression level first increases and then decreases. Mechanistically, CREB5 inhibits the decomposition of neuronal lipid droplets (LDs) by enhancing the transcriptional activity of the lipolysis‐related protein ApoL6, reducing the release of free fatty acids (FFA) and fatty acid oxidation (FAO), thereby decreasing ROS generation and lipid peroxidation, and ultimately inhibiting neuronal ferroptosis. In vitro experiments showed that CREB5 knockdown exacerbates neuronal death and inhibits axonal growth; in vivo experiments demonstrated that CREB5 knockdown hinders axonal growth and functional recovery in mice post‐SCI, while ApoL6 overexpression partially reverses these impairments.

CREB5 maintains the balance of neuronal lipid droplet metabolism by regulating ApoL6 and serves as a potential therapeutic target for inhibiting neuronal ferroptosis after SCI.

After spinal cord injury, neuronal CREB5 exhibits a biphasic trend of increased then decreased transcriptional activity and expression. By transactivating ApoL6, CREB5 inhibits lipid droplet catabolism, reduces reactive oxygen species and lipid peroxidation to suppress ferroptosis, thereby promoting axonal growth and functional recovery in mice.