Screening and identification of four serum miRNAs as novel potential biomarkers for cured pulmonary tuberculosis

Rapid and efficient methods for the determination of cured pulmonary tuberculosis (TB) are lacking. We screened serum miRNAs using the Solexa sequencing method among untreated TB patients, two-month treated TB patients, cured TB patients, and healthy controls. A total of 100 differentially expressed miRNAs were identified in cured TB patients, including 37 up-regulated (fold change >1.50, P < 0.05) and 63 down-regulated (fold change <0.60, P < 0.05) miRNAs. Gene ontology (GO) enrichment analysis revealed that most of the predicted genes were present in the nucleus with a strong protein binding function. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis strongly suggested alterations in the metabolic pathways. Following quantitative real time chain reaction (qRT-PCR), significantly reduced expression levels of miR-21-5p (0.30, P < 0.001), miR-92a-3p (0.63, P < 0.001), and miR-148b-3p (0.17, P < 0.001) were found in the cured TB patients compared with the untreated TB patients, while significantly increased expression levels of miR-21-5p (2.09, P = 0.001), miR-92a-3p (1.40, P = 0.005), and miR-148b-3p (4.80, P = 0.003) were found in the untreated TB patients compared with the healthy controls. And significantly increased level of miR-125a-5p was found between two-month treated TB patients and untreated TB patients (1.81, P = 0.004). We established a cured TB model with 83.96% accuracy by four miRNAs (miR-21-5p, miR-92a-3p, miR-148b-3p, and miR-125a-5p), and also established a diagnostic model with 70.09% accuracy. Our study provides experimental data for establishing objective indicators of cured TB, and also provides a new experimental basis to understand the pathogenesis and prognosis of TB.