Background Ankylosing spondylitis (AS) is a chronic inflammatory disease, which is difficult to diagnose in the early stages. Increasing evidences have shown that MicroRNAs (miRNAs) may serve as novel biomarkers for AS. Exosome can function as vehicles to deliver miRNAs in body fluids including saliva and plasma. However, the relationship between exosome-delivered miRNAs and AS has yet to be determined.
Objectives The aim of this study is to detect the altered miRNAs profiles of plasma-derived exosome in AS patients by small RNA-Seq Analysis.
Methods RiboTM kit was used to isolate exosome. Small RNA Sample Pre Kit was used to build libraries in 3 AS patients and 3 healthy volunteers (HV), following by IlluminaHiSeq platform sequencing and bioinformatics analysis. Quantitative reverse-transcription PCR (qRT-PCR) was used to confirm the expression of the highly-expressed miRNA in another 10 AS patients and 10 HV, and receiver-operator characteristic (ROC) curve was used to evaluate the diagnostic value of miRNAs.
Results Small RNA-Seq analysis showed that the Q30 value of HV and AS patients were higher than 95% (Fig.1-A). The amount of miRNA in HV and AS patients were (509.667±77.501) and (632.000±43.555). 80 up-regulated and 19 down-regulated exosomal miRNAs were identified in AS patients, compared with HV (|log2Ratio|>1, P <0.05) (Fig.1-B-C). The target genes of the 34 highly-expressed miRNAs from the 99 differently-expressed miRNAs were 7869, and the main function of these target genes are involved in the regulation of endocytosis and protein modification process analyzed by GO and KEGG. The qRT-PCR results indicated that the expression level of miRNA21–5P and miRNA423–5P in AS patients were (2.940±1.572) and (2.520±1.401) times higher than that of HV (Fig.1-D-E). ROC curve analysis showed that miRNA21–5P and miRNA423–5P had significant diagnostic value for AS with the AUC of 0.890 (CI95%: 0.723–1.057) and 0.835 (CI95%: 0.621–1.039) respectively (Fig.1-F).
Conclusions The miRNAs profiles in plasma-derived exosome of AS patients are significant different from HV. miRNA21–5P and miRNA423–5P are higher expressed in AS patients. Thus, plasma-derived exosomal miRNAs might be reliable biomarkers to identify AS.
El MA. Extra-articular manifestations of ankylosing spondylitis: prevalence, characteristics and therapeutic implications. Eur J Intern Med, 2011, 22(6):554–60.
Disclosure of Interest None declared