EZH2 Mediates miR-146a-5p/HIF-1α to Alleviate Inflammation and Glycolysis after Acute Spinal Cord Injury.

Shuangfei Ni,Huafeng Zhang,Bo Yang,Lei Xia,Yaoyao Xia

doi:10.1155/2021/5591582

Shuangfei Ni, Huafeng Zhang + Show 3 more

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https://doi.org/10.1155/2021/5591582

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Abstract

Acute spinal cord injury (ASCI) is a severe traumatic disease of the central nervous system, the underlying mechanism of which is unclear. This study was intended to study the role of EZH2 and miR-146a-5p/HIF-1α in inflammation and glycolysis after ASCI, providing reference and basis for the clinical treatment and prognosis of ASCI injury. We used lipopolysaccharide (LPS) to induce inflammation of microglia, and we constructed the ASCI animal model. qRT-PCR detected the relative expression levels of EZH2, HIF-1α, miR-146a-5p, IL-6, TNF-α, IL-17, PKM2, GLUT1, and HK2 in cells and tissues. Western blot was performed to detect the expression levels of EZH2, HIF-1α, H3K27me3, IL-6, TNF-α, IL-17, PKM2, GLUT1, and HK2. ChIP verified the enrichment of H3K27me3 in the miR-146a-5p promoter region. Bioinformatics predicted the binding sites of HIF-1α and miR-146a-5p, and dual-luciferase reporter assay verified the binding of HIF-1α and miR-146a-5p. ELISA detects the levels of inflammatory factors IL-6, TNF-α, and IL-17 in the cerebrospinal fluid of rats. The GC-TOFMS was used to detect the changes of glycolytic metabolites in the cerebrospinal fluid of rats. EZH2 could mediate inflammation and glycolysis of microglia. EZH2 regulates inflammation and glycolysis through HIF-1α. EZH2 indirectly regulated the HIF-1α expression by mediating miR-146a-5p. EZH2 mediates miR-146a-5p/HIF-1α to alleviate inflammation and glycolysis in ASCI rats. In the present study, our results demonstrated that EZH2 could mediate miR-146a-5p/HIF-1α to alleviate the inflammation and glycolysis after ASCI. Therefore, EZH2/miR-146a-5p/HIF-1α might be a novel potential target for treating ASCI.

Highlights

Acute spinal cord injury (ASCI) is a severe traumatic disease of the central nervous system (CNS) [1]
In order to study the inflammation, glycolysis, and relationship between HIF-1α and Enhancer of zeste homology 2 (EZH2) in microglia treated with LPS, Quantitative Real-Time PCR (qRT-PCR) and Western blot were performed to detect EZH2; HIF-1α; inflammatory factors IL-6, TNF-α, and IL17; and glycolysis-related gene PKM2, GLUT1, and HK2 expression levels in the Control and LPS groups. qRT-PCR and Western blot showed that compared with the Control group, EZH2 and HIF-1α expression in the LPS group was increased (fold change ≈ 2; ∗P < 0:05 vs. Control group; Figures 1(a), 1(b), and 1(e))
The expression of inflammatory factors IL-6, TNF-α, and IL-17 and glycolysis-related genes PKM2, GLUT1, and HK2 increased in the LPS group (fold change ≈ 1:5 ~ 3; ∗P < 0:05 vs. Control group; Figures 1(c)–1(e)), which indicated that HIF-1α inflammation and glycolysis in microglia treated with LPS were associated with upregulated EZH2

Summary

Introduction

Acute spinal cord injury (ASCI) is a severe traumatic disease of the central nervous system (CNS) [1]. Spinal cord tissues respond to injury after ASCI, and the gene expression profile of cells changes, which affects the repair of injury after ASCI, and epigenetic regulation plays an important role. Enhancer of zeste homology 2 (EZH2) is located on the human chromosome 7q35. EZH2 mainly catalyzes the histone H3 lysine 27 trimethylation (H3K27me3), which mediates the change of chromatin structure, closes transcription factor binding sites, inhibits the transcription of target genes, and participates in many physiological or pathological processes [2]. Studies have shown that nerve damage dramatically increases the number of microglia expressing EZH2 [3]. It is an effective strategy to improve the functional recovery after

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