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, non-coding 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 serum-derived 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-miR-let7e, 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 M. avium vs. Mtb was upregulated (P ≤ 0.01, P ≤ 0.0001, and P ≤ 0.0001, respectively), same as miRs let7e and 20a expression which was increased in M. abscessus vs. Mtb (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.