Upregulated lncRNA-NEF predicts recurrence and poor treatment outcomes of ankylosing spondylitis

Abstract

Introduction: Osteoporosis is related to lncRNA-neighboring enhancer of FOXA2 (NEF) and inversely correlated to ankylosing spondylitis (AS), implying that lncRNA-NEF might also relate to AS. Thus, the study was carried out to investigate the involvement of lncRNA-NEF in AS.

Methods: The study included 60 AS patients and 60 healthy controls. LncRNA-NEF expression in synovial fluid samples was analyzed by reverse transcription quantitative real-time polymerase chain reaction. Disease activity of the 60 AS patients was determined using the Ankylosing Spondylitis Disease Activity Score (ASDAS) 1-4 and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Western blot was carried out to investigate the effects of lncRNA-NEF on inflammatory factors in human fibroblast-like synovial (HFLS) cells. A 3-year follow-up was performed to analyze the role of lncRNA-NEF in the prediction of the recurrence of AS.

Results: Our study observed that lncRNA-NEF expression was upregulated in synovial fluid of AS patients and significantly correlated with the ASDAS 1-4, BASDAI, erythrocyte sedimentation rate (ESR), and C-reactive protein level (p < .05). Treatment with nonsteroidal anti-inflammatory drugs significantly downregulated lncRNA-NEF expression (p < .01). A 3-year follow-up showed that patients with high lncRNA-NEF levels had a high recurrence rate (hazard ratio = 2.266). In addition, lncRNA-NEF was found to regulate the expression of inflammatory factors in HFLS cells.

Conclusions: Therefore, lncRNA-NEF upregulation can predict recurrence and poor treatment outcomes of AS and has a great potential to serve as a predictive biomarker factor for the recurrent AS.

Keywords: ankylosing spondylitis; lncRNA-NEF; recurrence; synovial fluid.

Figure 1

LncRNA‐NEF expression in synovial fluid of ankylosing spondylitis (AS) patients and its predictive value for recurrence LncRNA‐NEF levels in synovial fluid samples from AS patients (n = 60) and healthy controls (n = 60) were measured by reverse transcription quantitative real‐time polymerase chain reaction (RT‐qPCR) (A). LncRNA‐NEF levels in synovial fluid samples from the 60 AS patients before and after treatment with nonsteroidal anti‐inflammatory drugs were measured by RT‐qPCR and compared (B). The 60 AS patients were divided into high and low lncRNA‐NEF level groups (n = 30) with the median pretreatment lncRNA‐NEF level as the cutoff value. Based on the 3 years’ follow‐up data, AS recurrence‐free curves were plotted for both groups and compared using the log‐rank test (C). *p < .05.

Figure 2

NEF regulated the expression of inflammatory factors in human fibroblast‐like synovial (HFLS). HFLS cells were obtained from ankylosing spondylitis patients and transfected with NEF overexpression plasmid, si‐NEF, or their negative controls (pcDNA or si‐con). The protein levels of interleukin‐1β (IL‐1β), interleukin‐6 (IL‐6), and tumor necrosis factor‐α (TNF‐α) in these cells were detected by Western blot. LncRNA‐NEF overexpression promoted the expression of inflammatory factors, while lncRNA‐NEF knockdown inhibited the expression of inflammatory factors. *p < .05.