Lipid Droplets Metabolism Mediated by ANXA7-PPARγ Signaling Axis Regulates Spinal Cord Injury Repair in Mice

Abstract

Spinal cord injury is characterized by high incidence and high disability, and the specific targets and drugs have not yet been explored. Lipid droplet is a type of organelles that regulates lipid metabolism and oxidative stress. And the regulatory mechanisms of lipid droplets on spinal cord injury remain unclear. Herein, it is found that GTPase activation of Annexin A7 (ANXA7) promotes the up-regulation of genes related to lipid droplet formation. ANXA7 can interact with peroxisome proliferator-activated receptor gamma (PPARγ) to enhance the stability of PPARγ, and promote lipid droplet formation and interaction with mitochondria through promoting Perilipin 5 expression. Then, oxidative stress and lipid peroxidation are inhibited due to the promotion of nuclear factor erythroid 2-related factor 2 (NRF2) nuclear translocation and expression of glutathione peroxidase 4 (GPX4). ANXA7 activation promotes lipid droplet formation and mitochondria-lipid droplet interaction by enhancing nuclear translocation of PPARγ, which contributes to inhibiting lipid peroxidation and neuron damage. Furthermore, activation of PPARγ can promote neural function recovery and spinal cord repair in mice. The focus of this study is to investigate the effects of lipid droplets regulated by ANXA7/PPARγ, providing new targets and strategies for spinal cord injury.