MiRNA-seq in blood of myasthenia gravis (MG) patients responder and non-responder to immunosuppressive treatment

Purpose: to identify specific miRNAs as biomarkers associated with immunosuppressive treatment response in MG patients. Methods: Blood miRNome profiles of 15 responder and 15 non-responder MG patients by miRNA-seq using Illumina NextSeq 500 sequencing. Raw data were de-multiplexed and FASTQ files for each sample were generated using the bcl2fastq software. FASTQ data were checked using the FastQC tool. After mapping the data and counting to relevant entries in miRBase 20 (http://www.mirbase.org/), the numbers of known microRNAs was calculated.For statistical analysis, along with TPM normalization, the trimmed mean of M-values (TMM) normalization method was used. Validation was perfomed using TaqMan Advanced real-time PCR on microRNA array cards. Results: An average of 9.98 million reads was obtained per sample. We identified 41 statistically significant differentially expressed miRNAs (logFoldChange from +1.371 to -1.439, p < 0.05), including 18 miRNAs up-regulated and 23 miRNAs down-regulated in non-responder versus responder MG patients. 23 miRNAs were selected for validation. Among them, three miRNAs were significantly decreased in non-responder versus responder patients, whereas two showed an opposite trend. Conclusions: We identified a blood miRNA signature associated with drug responsiveness in MG patients, that could represent a valuable tool for therapeutic follow-up in MG. Overall design: MiRNome profiling in responder and non-responder MG patients by miRNA-seq using an Illumina's platform.