Department of Spine Surgery, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China.
Bioengineered. 2022 Mar;13(3):6396-6408. doi: 10.1080/21655979.2022.2042987.
This study aimed to investigate the role played by microRNA (miR)-137 in intervertebral disc degeneration via targeting activin A receptor type I (ACVR1) and the underlying mechanism. Human nucleus pulposus cells were exposed to 10 ng/mL lipopolysaccharide (LPS) to establish an intervertebral disc degeneration model. ACVR1, extracellular matrix degradation-associated genes (aggrecan and collagen type II) and miR-137 levels were assessed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blotting assays. The MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) assay and flow cytometry were used to evaluate nucleus pulposus cell viability and apoptosis. Additionally, the association between miR-137 and ACVR1 was predicted and verified using bioinformatic software and dual-luciferase reporter assays. Furthermore, the secretion of inflammatory factors was analyzed via enzyme linked immunosorbent assay (ELISA). Our results confirmed that ACVR1 was upregulated in lipopolysaccharide-treated nucleus pulposus cells. Lipopolysaccharide suppressed cell viability, promoted apoptosis, enhanced the secretion of inflammatory factors, and reduced aggrecan and collagen type II expression. However, these results were reversed upon ACVR1 silencing. Our data revealed that ACVR1 directly targets miR-137 and is negatively regulated by miR-137 in nucleus pulposus cells. Additionally, the miR-137 mimic promoted cell growth, reduced cell apoptosis, reduced the secretion of inflammatory cytokines, and accelerated extracellular matrix accumulation in lipopolysaccharide-exposed nucleus pulposus cells. However, ACVR1 plasmid abolished the functions of the miR-137 mimic in lipopolysaccharide-exposed nucleus pulposus cells. Together, these findings indicate that miR-137 suppresses the inflammatory response and extracellular matrix degradation in lipopolysaccharide-treated nucleus pulposus cells by targeting ACVR1.
本研究旨在探讨 microRNA（miR）-137 通过靶向激活素 A 受体型 I（ACVR1）在椎间盘退变中的作用及其潜在机制。采用 10ng/mL 脂多糖（LPS）处理人椎间盘髓核细胞，建立椎间盘退变模型。采用逆转录定量聚合酶链反应（RT-qPCR）和 Western blot 检测 ACVR1、细胞外基质降解相关基因（聚集蛋白聚糖和 II 型胶原）和 miR-137 的水平。MTT（3-(4,5-二甲基-2-噻唑基)-2,5-二苯基-2-H-四唑溴盐）和流式细胞术检测髓核细胞活力和凋亡。此外，采用生物信息学软件和双荧光素酶报告基因检测预测和验证 miR-137 与 ACVR1 的关联。进一步通过酶联免疫吸附测定（ELISA）分析炎性因子的分泌。结果证实 LPS 处理的髓核细胞中 ACVR1 上调。LPS 抑制细胞活力，促进细胞凋亡，增强炎性因子分泌，降低聚集蛋白聚糖和 II 型胶原表达。沉默 ACVR1 可逆转这些结果。研究数据表明，ACVR1 可直接靶向 miR-137，且在髓核细胞中受 miR-137 负调控。此外，miR-137 模拟物促进细胞生长，减少细胞凋亡，减少 LPS 暴露的髓核细胞中炎性细胞因子的分泌，并加速细胞外基质的积累。然而，ACVR1 质粒消除了 miR-137 模拟物在 LPS 暴露的髓核细胞中的作用。综上，这些发现表明 miR-137 通过靶向 ACVR1 抑制 LPS 处理的髓核细胞中的炎症反应和细胞外基质降解。
