MAFG Induces the Methylation of CRYAB to Promote the Activation of A1 Astrocyte After Spinal Cord Injury

TL;DR

This study shows that silencing MAFG reduces harmful astrocyte activation and inflammation after spinal cord injury, possibly by inhibiting CRYAB methylation.

Contribution

The study reveals a novel role of MAFG in promoting A1 astrocyte activation through CRYAB methylation after spinal cord injury.

Findings

MAFG upregulation is linked to A1 astrocyte activation after spinal cord injury.

Silencing MAFG reduces neuroinflammation and improves functional recovery in rats.

MAFG silencing inhibits CRYAB methylation, which may contribute to reduced astrocyte activation.

Abstract

To investigate the effects of MAF bZIP transcription factor G (MAFG) on the transformation of A1/A2 reactive astrocytes and the production of inflammatory factors after spinal cord injury (SCI).

An SCI model was established using Sprague–Dawley rats. Astrocyte conditioned medium (ACM) and lipopolysaccharide (LPS) were used to induce the generation of type A1 astrocytes. MAFG‐, CRYAB‐, C3‐, and S100A10‐positive cells were examined using immunofluorescence. The expression of MAFG, TNF‐α, IL‐1β, IL‐6, C3, Serping1, Sphk1, S100A10, CRYAB, DNMT1, DNMT3a, and DNMT3b was detected through RT‐PCR and/or Western blot. The inclined plate test and Basso‐Beattie‐Bresnahan scores were used to evaluate the motor function in rats. Hematoxylin and eosin and Nissl staining were performed to assess pathological changes in the rat spinal tissues. In rat astrocytes, IL‐1β and IL‐6 levels were examined via enzyme‐linked immunosorbent assay.

A1 astrocyte activation was accompanied by MAFG upregulation in rat spinal cord tissues after SCI. MAFG silencing inhibited the activation of A1 astrocytes and inflammation and improved neurological outcomes and functional recovery in rats after SCI. In ACM‐treated rat astrocytes, MAFG silencing inhibited A1 astrocyte activation, inflammation, and CRYAB methylation. Moreover, 5‐Aza (an inhibitor of methylation) further inhibited the activation of A1 astrocytes and inflammation, whereas DNMT3b overexpression had the opposite effect.

Silencing MAFG reduced the activation of A1 astrocytes and neuroinflammation and improved functional recovery after SCI, which might be involved in the inhibition of CRYAB methylation.

All in all, silencing MAFG inhibited the activation of A1 astrocyte and neuroinflammation through regulating CRYAB methylation.

In SCI tissues, A1 astrocyte polarization is accompanied by MAFG upregulation.MAFG silencing promotes rat functional recovery after SCI.MAFG silencing inhibits A1 astrocyte polarization and neuroinflammation.MAFG silencing inhibits the methylation of CRYAB.

In SCI tissues, A1 astrocyte polarization is accompanied by MAFG upregulation.

MAFG silencing promotes rat functional recovery after SCI.

MAFG silencing inhibits A1 astrocyte polarization and neuroinflammation.

MAFG silencing inhibits the methylation of CRYAB.

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