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Objective To explore the potential predictive value of plasma exosomal miR-422a in different time after ischaemic stroke (1, 2, 3, 4 day) .Methods Retrospective study.Forty patients diagnosed with ischaemic stroke ( IS ) and ten age and sex matched people who underwent a standard physical examination were recruited from the First Affiliated Hospital of Guangxi Medical University between May 2016 and December 2016.Plasma exosomes were extracted by use of related kit and the expression level of plasma exosomal miR-422a in both IS patients (1, 2, 3, 4 day) and healthy controls were examined via quantitative real-time polymerase chain reaction ( qRT-PCR ) .The areas under the curve ( AUC ) of the receiver operating characteristic curve were constructed to evaluate the diagnostic accuracy of the miR -422a in IS, and one-way analysis of variance followed by the Games-Howell post hoc test was used for difference analysis.Results The exosomes isolated from human plasma showed round or oval vesicles , the average particle size was 128.2 nm and with maximum peak distribution of 186.9 nm.Moreover , all of the isolated exosomes were positive for a marker , with the CD63-positive rate at 80.6％ and the CD81-positive rate at 91.7％.qRT-PCR confirmed that miR-422a was expressed in human plasma exosomes , and the expression levels of plasma exosomal miR-422a [median relative values, 1.221 (95％CI:0.640-1.802) for healthy group, 4.418 (95％CI:2.642-6.193) for group of 1 dayafter IS, 2.912 (95％CI:2.262-3.562) for 2 day, 2.744 (95％CI:2.000-3.487) for 3 day and 0.449 (95％CI:0.170-0.727) for 4 day] were significantly increased in the time after IS 1, 2, 3 day ( F=13.57, P<0.05, P<0.01, P<0.05, respectively;and the AUC values were 0.920, 0.945, 0.870, respectively ) .The expression of plasma exosomal miR-422a on the 4th day after IS were lower than those in other IS groups ( F=13.57,P<0.005, P<0.001, P<0.001, respectively), and no statistical significance was found between the expression of plasma exosomal miR-422a on the 4th day after IS than that in the control group [0.449 (95％CI:0.170-0.727)].Conclusion Plasma exosomal miR-422a showed high diagnostic value as blood-based biomarker for diagnosing IS in the early phase (1-3 d).
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Objective To explore the microRNAs regulation of CXC chemokine ligand 13 (CXCL13) in patients with myasthenia gravis combined with thymic hyperplasia (MGH).Methods Thirteen MGH tissues and 13 normal thymus tissues,collected in our hospital from March 2012 to August 2013,were used in our study.Total RNAs from these tissues were extracted by trizol and hybridized with the microarray.The miRNAs targeting CXCL13 gene-3'untranslated region were predicted by using bioinformatics.Real-time fluorogenic quantitative PCR (QRT-PCR) was employed to detect the expressions ofCXCL13 mRNAs and microRNAs in thymus tissues.Luciferase assay was used to analyze the miRNAs modulated CXCL13 expression.Results The miRNA microarray chip analysis identified 33 miRNAs differentially expressed in MGH tissues as compared with those in the control group,miR-548k was one of most obvious down-regulated miRNAs (1.98 fold).Bioinformatical analysis indicated that miR-548k can target CXCL13 3' UTR.QRT-PCR showed that the expression of CXCL13 mRNA was up-regulated and miR-548k was down-regulated in thymus hyperplasia tissues of MGH group as compared with those in the control group(4.93±l.95 vs.1.04±0.20; 0.55±0.20 vs.1.33±0.36,P＜0.05); and they showed a negative correlation (r=-0.93,P=0).003).As compared with that in the control group (1.000±0.050),the luciferase activity of pmiR-RB-REPORTTM-CXCL13-3'UTR treated with miR-548k mimics (0.385±0.016) decreased 61.5％,with significant difference (P＜0.05).Conclusion MiR-548k inhibits CXCL13 expression by post-transcriptional gene silencing to promote MG development and progression.