Differential Expression Of LncRNAs Correlate With The Disease Risk And Activity In Ankylosing Spondylitis

BackgroundAnkylosing Spondylitis(AS)is a chronic inflammatory autoimmune disease.Its characteristics mainly include systemic inflammation and pathological osteogenesis.The continued development and progress of AS will eventually lead to spinal fusion and ligament ossification,resulting in disability.Long non-coding RNA(lncRNA)is a transcript produced by the transcription of non-coding sequences in the genome,with a length of more than 200 nucleotides,and without the ability to translate into protein.LncRNAs can regulate the development of various immune cells,such as macrophages,dendritic cells(DCs),T lymphocytes and B lymphocytes.With the rise of next-generation sequencing technology,more and more lncRNAs have been discovered,which have important biological functions.lncRNAs are important in the immune system that can directly bind with transcription factors in the cytoplasm to regulate the development and differentiation of immune cells,and can also regulate the transcription of inflammatory genes by participating in histone modification or binding with hnRNP.However,the specific ways and mechanisms of lncRNAs regulating the occurrence of immune diseases remain to be studied.ObjectiveLncRNAs played an important role in the regulation of immune function,however,the mechanism of these lncRNAs in AS was still not fully understood.Therefore,we analyzed and compared differentially expressed(DE)lncRNAs in AS.The purpose is to screen out the differentially expressed AS-related lncRNAs in some patients,providing potential molecular markers for clinical diagnosis and targeted therapy of AS by verifying the results of sequencing.MethodsSeventeen patients with active AS(ASDAS-CRP≥1.3),seventeen patients with inactive AS(ASDAS-CRP<1.3),and seventeen healthy controls were enrolled,and high-throughput lncRNA sequencing on 5 patients in each group was performed.Based on the standard of|log2 Fold change(FC)|≥1 and P value≤0.05,5 lncRNAs with significant differences were screened from the sequencing results according to the P value and multiple sizes of the expression difference.Gene ontology(GO)analysis and Kyoto Encyclopedia of Genes and Genome(KEGG)enrichment analysis were performed on the DE lncRNAs.Real-time quantitative polymerase chain reaction(RT-qPCR)was used to verify the candidate DE lncRNAs in the other 12 patients from each group,and receiver operating characteristic(ROC)curve was used to detect the potential biomarkers with high specificity and sensitivity.ResultsHigh-throughput sequencing showed that a total of 378 IncRNAs were upregulated and 328 lncRNAs were downregulated in patients with active AS compared with inactive AS;a total of 517 lncRNAs were upregulated and 441 lncRNAs were downregulated in patients with active AS compared with healthy controls;a total of 349 lncRNAs were upregulated and 331 lncRNAs were downregulated in patients with inactive AS compared with healthy controls.Enrichment analysis found that DE lncRNAs were mainly related to inflammation-related pathways,such as antigen processing and presentation,inflammatory mediator regulation of TRP,cell adhesion molecules(CAM),AMPK signaling pathway,Wnt signaling pathway and cAMP signaling pathway,etc.Subsequent RT-qPCR verification results showed that lnc-CKMT2-AS1 and Inc-LEF1-AS1 were elevated in patients with active AS compared with inactive AS and healthy controls,and the expression of lnc-CKMT2-AS1 and lnc-LEF1-AS1 is positively correlated with the level of ASDAS-CRP,besides provided good predictive values for AS risk by ROC curve analysis.ConclusionsMany lncRNAs are differentially expressed in patients with AS,suggesting that lncRNAs may play important roles in the pathogenesis of AS,and lnc-CKMT2-AS1 and lnc-LEF1-AS1 may have predictive values in the risk and disease activity of AS.