Expression profiling & functional characterization of candidate miRNAs in serum exosomes among Indians with & without HIV-tuberculosis coinfection.

Background & objectives Despite the evidence of population differences in miRNA expression, limited information is available about the expression profile of miRNAs in Indian tuberculosis (TB) patients. The present study aimed to investigate the expression profile of candidate serum exosomal microRNAs in Indian patients with and without HIV-TB coinfection. Methods The pool samples of serum exosomes of study participants (HIV-TB coinfection, extra-pulmonary TB, HIV mono-infection, pulmonary TB) and healthy humans were processed for the isolation of total RNA followed by miRNA analysis using miRCURY LNA human focus PCR panel by real-time PCR. The significantly altered miRNAs were identified using differential expression analysis. The target genes prediction and potential functional analysis of exclusively differentially expressed miRNAs were performed using bioinformatics tools. Results The expression profile of 57, 58, 49 and 11 miRNAs was significantly altered in exosome samples of HIV-TB coinfected, extra-pulmonary TB, HIV mono-infected and pulmonary TB patients compared to healthy controls, respectively. The set of three (hsa-let-7i-5p, hsa-miR-24-3p, hsa-miR-92a-3p), three (hsa-miR-20a-5p, hsa-let-7e-5p, hsa-miR-26a-5p) and four (hsa-miR-21-5p, hsa-miR-19a-3p, hsa-miR-19b-3p, hsa-miR-146a-5p) miRNAs were exclusively significantly differentially expressed in study participants with HIV-TB coinfection, extra-pulmonary TB and pulmonary TB, respectively. Most of the target genes of exclusively differentially expressed miRNAs were enriched in pathways in cancer, MAPK signalling pathway and Ras signalling pathway. Interpretation & conclusions The present study demonstrates a distinct expression profile of miRNAs in serum exosomes of the study participants and identified crucial miRNAs which may have a significant impact on the biomarker analysis and pathogenesis of TB in Indian patients.