Abstract: Objective · To study the microRNA (miRNA) derived plasma exosomes, and to find the potential biomarker for the diagnosis of tuberculosis. Methods · Macrophages [Bacille Calmette-Guérin (BCG) group] human monocytic leukemia cells (THP-1) were infected with BCG, and uninfected macrophages were set as control group. Exosomes the cell culture supernatant of the two groups were obtainedultracentrifugation. The morphology and protein markers of exosomes were identifiedtransmission electron microscopy (TEM) and Western blotting. Total RNA of exosomes was analyzedtranscriptome sequencing. Three miRNAs with different were selected the sequencing results, and the plasma exosomes of 10 patients with tuberculosis (tuberculosis group) and 8 healthy volunteers (healthy control group) were clinically verified. The target genes of miRNAs with potential differential were predictedTargetScan, miRDB and PicTar databases. Results · The sequencing results of exosomes the cell culture supernatant showed that compared with the control group, the of miRNA-323a-3p, miRNA-29a-3p and miRNA-29b-3p in BCG group were significantly different. In clinical verification, only miRNA-323a-3p between the tuberculosis group and the healthy control group was statistically significant (P0.004). miRNA-323a-3p was significantly down-regulated in the plasma-derived exosomes of tuberculosis patients, which was consistent with the results of sequencing results. Conclusion · The of miRNA-323a-3p plasma exosomes in patients with tuberculosis is significantly down-regulated, and its target gene is closely related to autophagy, which is expected to provide new ideas for the mechanism of tuberculosis.

Key words: exosome, micro RNA (miRNA), miRNA-323a-3p, tuberculosis, ultracentrifugation