Evaluation of miR-let-7f, miR-125a, and miR-125b expression levels in sputum and serum samples of Iranians and Afghans with pulmonary tuberculosis

The role of microRNAs (miRNAs) in tuberculosis infection is well established. As microR- NAs are able to change expression profiles according to different conditions, they can be useful biomarkers. Iranians and Afghans with tuberculosis were studied for three immune-related miRNAs (miR-let-7f, miR-125a, and miR-125b).

A total of 60 Iranian and Afghan patients with active pulmonary TB were enrolled in the Pulmo- nary Department of the Pasteur Institute of Iran. Serum and sputum samples were collected simultaneously from all partici- pants. A Real-time PCR was conducted to detect differentially expressed miRNAs.

Iranian (P<0.0001) and Afghan (P<0.0001) serum samples and Afghan (P<0.0001) sputum samples overexpressed miR-125a, whereas Iranian sputum samples showed downregulation (P=0.0039). In both Iranian (P<0.0001; P=0.0007) and Afghan (P<0.0001; P<0.0001) serum and sputum samples, miR-125b was overexpressed. Furthermore, miR-let-7f down- regulation was observed in serum and sputum samples (P<0.0001), whereas Iranian sputum samples had no statistically significant differences (P=0.348).

Overexpression of miR-125a and miR-125b has been detected in Iranian and Afghan samples. In both races, miR-let-7f downregulation has been confirmed. Identification of miRNA profiles under different conditions opens the door to evaluating potential new biomarkers for diagnosis, disease monitoring, and therapeutic markers in TB infection.