Apelin Promotes ECM Synthesis by Enhancing Autophagy Flux via TFEB in Human Degenerative NP Cells under Oxidative Stress.

Wei Jiang,Xuemei Zhang,Pei Zhao

doi:10.1155/2020/4897170

Wei Jiang, Xuemei Zhang + Show 1 more

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https://doi.org/10.1155/2020/4897170

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Abstract

Background Apelin alleviates oxidative stress which contributes to the development of aging. IVDD is a disease closely correlated to aging and oxidative stress which is known to be harmful to NP cells' matrix synthesis. The purpose of the present study was to investigate the role and underlying mechanism of Apelin in NP cells' matrix degradation under oxidative stress. Methods First, the mRNA and protein expressions of Apelin were checked by RT-PCR and Western blot in NP from normal and degenerative IVD to explore the relationship between Apelin and IVDD preliminarily. Then, H2O2 was used to mimic oxidative stress of NP cells. After treated with Apelin 13 and CQ, the GAG content was assessed by DMMB and the mRNA/protein expressions of NP matrix macromolecules (Collagen II and Aggrecan) and autophagy-related markers (LC3 and p62) were assessed by RT-PCR/Western blot. Finally, TFEB was knocked down by esiRNA-TFEB transfection and the nucleoprotein expression of TFEB and autophagy-related markers (LC3 and p62) were assessed by Western blot to discuss whether TFEB is involved in Apelin regulating autophagy flux in NP cells under oxidative stress. Results Our data first confirmed that the mRNA and protein expressions of Apelin were decreased with IVDD. Furthermore, Apelin increased GAG content of NP cells and mRNA/protein expressions of NP matrix macromolecules (Collagen II and Aggrecan) and promoted autophagic flux (LC3II/I increased and p62 decreased) under oxidative stress. Finally, after transfected with esiRNA-TFEB, Apelin cannot promote autophagic flux any more in human degenerative NP cells. Conclusion Our data indicated that Apelin promotes ECM synthesis by enhancing autophagy flux via TFEB in human degenerative NP cells under oxidative stress. This viewpoint may provide a new therapeutic idea for IVDD.

Highlights

Low back pain (LBP) has become a severe socioeconomic problem worldwide for its contribution to the drop in life quality and even disability in adults [1, 2]. ough the veritable cause of LBP is complex and unclear, many studies have demonstrated that intervertebral disc degeneration (IVDD) is a main cause of LBP [3,4,5,6]
Patients and nucleus pulposus (NP) Samples. e study complied with the Declaration of Helsinki and with approval from the Ethics Committee of Chongqing Medical University, and informed consent of all the patients involved in our study was obtained. e degeneration grade of Intervertebral disc (IVD) was classified according to the Pfirrmann classification [24] by magnetic resonance imaging (MRI) scan of spine prior to surgery
In order to confirm the relationship between Apelin and IVDD, RTPCR/Western blot was applied to measure the mRNA/ protein expression of Apelin of NP from lumbar vertebral fracture (LVF) and degenerative disc disease (DDD)

Summary

Introduction

Low back pain (LBP) has become a severe socioeconomic problem worldwide for its contribution to the drop in life quality and even disability in adults [1, 2]. ough the veritable cause of LBP is complex and unclear, many studies have demonstrated that intervertebral disc degeneration (IVDD) is a main cause of LBP [3,4,5,6]. Changes in the NP at the cellular and molecular levels will result in damage of structure and function of the extracellular matrix (ECM) and eventually lead to the loss of biomechanics and degeneration [7]. In light of this point, the maintenance of a healthy NP homeostasis may decrease the degradation of ECM and postpone the progression of the IVDD. Apelin increased GAG content of NP cells and mRNA/protein expressions of NP matrix macromolecules (Collagen II and Aggrecan) and promoted autophagic flux (LC3II/I increased and p62 decreased) under oxidative stress. Our data indicated that Apelin promotes ECM synthesis by enhancing autophagy flux via TFEB in human degenerative NP cells under oxidative stress. is viewpoint may provide a new therapeutic idea for IVDD

Methods

Results

Conclusion