骨关节炎（OA）是老年人中一种常见的炎症性关节软骨退化性关节病。本研究旨在探讨长链非编码RNA（lncRNA）NEAT1在OA发病机制中的新机制。本研究纳入10名OA患者和10名正常个体。通过脂多糖（LPS）诱导的人正常软骨细胞建立OA细胞模型。利用半胱氨酸（L-cysteine）和凡纳肽（papain）混合物（比例为1：2）给右膝关节注射，建立OA Wistar大鼠模型。采用定量逆转录-聚合酶链反应确定NEAT1、microRNA（miR）-374b-5p和post-GPI连接蛋白1（PGAP1）的表达水平，而双荧光素酶报告实验则用于验证它们之间的目标关系。通过流式细胞术分析计算细胞周期和凋亡。采用CCK-8实验评估软骨细胞的增殖潜力。通过Western blotting测定细胞周期相关蛋白（Cyclin A1、Cyclin B1和Cyclin D2）和促凋亡蛋白（Caspase3和Caspase9）的水平。通过ELISA测定肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）和IL-6的水平。通过苏木精-伊红（HE）染色对OA大鼠进行病理检查。 在OA患者、LPS诱导的软骨细胞和OA大鼠中发现了NEAT1的显著下调以及miR-374b-5p的高表达。NEAT1通过靶向miR-374b-5p来调控PGAP1的表达。NEAT1的缺失或miR-374b-5p的上调显著加速了软骨细胞凋亡，导致G1/S期阻滞并促进炎症细胞因子的分泌，而PGAP1外源表达对软骨细胞具有相反的影响。此外，我们进一步证明了miR-374b-5p的上调减弱了PGAP1过表达对LPS诱导的软骨细胞的影响。 NEAT1的降低通过miR-374b-5p/PGAP1通路引发OA的发展。这表明，调控轴NEAT1/miR-374b-5p/PGAP1是一种新的、有前景的OA治疗靶点。 © 2023年，BioMed Central Ltd.，Springer Nature的一部分。

Osteoarthritis (OA), characterized by inflammation and articular cartilage degradation, is a prevalent arthritis among geriatric population. This paper was to scrutinize the novel mechanism of long noncoding RNA (lncRNA) NEAT1 in OA etiology.A total of 10 OA patients and 10 normal individuals was included in this study. Cell model of OA was built in human normal chondrocytes induced by lipopolysaccharide (LPS). An OA Wistar rat model was established through intra-articular injection of L-cysteine and papain mixtures (proportion at 1:2) into the right knee. Quantitative reverse transcription-polymerase chain reaction was employed to ascertain the expression levels of NEAT1, microRNA (miR)-374b-5p and post-GPI attachment to protein 1 (PGAP1), while dual-luciferase reporter experiments were used for the validation of target relationship among them. Cell cycle and apoptosis were calculated by flow cytometry analysis. CCK-8 assay was done to evaluate the proliferative potentials of chondrocytes. The levels of cell cycle-related proteins (Cyclin A1, Cyclin B1 and Cyclin D2) and pro-apoptotic proteins (Caspase3 and Caspase9) were measured by western blotting. Tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β) and IL-6 levels were determined via ELISA. Hematoxylin & eosin (HE) Staining was used for pathological examination in OA rats.Pronounced downregulation of NEAT1 and PGAP1 and high amounts of miR-374b-5p were identified in OA patients, LPS-induced chondrocytes and OA rats. NEAT1 targeted miR-374b-5p to control PGAP1 expression. Loss of NEAT1 or upregulation of miR-374b-5p dramatically accelerated apoptosis, led to the G1/S arrest and promoted the secretion of inflammatory cytokines in LPS-induced chondrocytes, while ectopic expression of PGAP1 exhibited the opposite influences on chondrocytes. Additionally, we further indicated that upregulation of miR-374b-5p attenuated the effects of PGAP1 overexpression on LPS-induced chondrocytes.Reduced NEAT1 induces the development of OA via miR-374b-5p/PGAP1 pathway. This suggests that the regulatory axis NEAT1/miR-374b-5p/PGAP1 is a novel and prospective target for OA treatment.© 2023. BioMed Central Ltd., part of Springer Nature.