Alireza Javadi1, Masoud Shamaei2*, Payam Tabarsi2, Elaheh Ainy3, Bahram Kazemi4*
Background: Mycobacteria could invade the host’s immune system to survive and persist in the host through different mechanisms such as the expression modulation of microRNAs (miRNAs). microRNA is a small, noncoding oligonucleotide that regulates gene expression and transcription. miRNAs' differential expressions in disease phenomena can serve as biomarkers. The expression level of serum-derived exosomal miRNAs from mycobacteria patients could result to enhance monocyte cell apoptosis. This study tries to evaluate four serumderived exosomal miRNAs as a potential mycobacterial biomarker.
Methods: Serum-derived exosomes were purified from serum samples of 55 patients with pulmonary tuberculosis or non-tuberculosis and 30 healthy controls. The expression level of Hsa-miR-20a-5p, Hsa-miR-29a, Hsa-miRlet7e, and Hsa-miR-155 was evaluated using qRT-PCR.
Results: In TB patients, the expression level of miR-20a-5p, miR-29a, and miR-let7e were significantly increased (p ≤ 0.0001), but the miR-155 expression level decreased. The receiver operating characteristic (ROC) curve analysis determined effective diagnostic biomarkers of miRNAs with an AUC=0.6933 for miR-20 (p ≤ 0.01), AUC=0.6011 for miR-29a (p ≤ 0.17), AUC=0.7322 for miR-let7e: (p ≤ 0.002), and AUC=0.7456 for miR- 155 (p ≤ 0.001) for active tuberculosis. The expression of miR-let7e, 20a, and 29a in Mycobacterium avium vs. Mycobacterium tuberculosis was up regulated (p ≤ 0.01, p ≤ 0.0001, and P ≤ 0.0001, respectively), same as miRs let7e and 20a expression which was increased in Mycobacterium abscessus vs. Mycobacterium tuberculosis (P ≤ 0.0001 and P ≤ 0.002, respectively).
Conclusion: In conclusion, circulating exosomal microRNA miR-20, miR-let7e, and miR-155 have diagnostic potential for active pulmonary tuberculosis. Furthermore, the study facilitates the development of potential biomarkers of pulmonary tuberculosis and non-tuberculosis.