Expression and bioinformatic analysis of miR-29 family, target gene IFN-γ in CD4(+) T cells from subjects with latent tuberculosis infection

Abstract

To investigate the effect of latent and active pulmonary tuberculosis(TB) on expression of miR-29 family and target gene IFN-γ in CD4(+)T cells. Subjects from two hospitals of Weifang were enrolled from March 2012 to December 2012 and divided into three groups: active TB group(30 cases), latent tuberculosis infection(LTBI) group(25 cases) and healthy control group(30 cases). CD4(+) T cells in blood were collected from the three groups.Levels of miR-29a, miR-29b and miR-29c were measured by nucleic acid hybridization and RT-qPCR.Expression of IFN-γ was analyzed by RT-qPCR. Target genes of miR-29 family were predicted with both TargetScan and PicTar.GO annotation and pathway overrepresentation were further analyzed with David database and Cytoscape. Levels of miR-29a, miR-29b and miR-29c showed significant differences among the three groups(P < 0.05): levels of miR-29b and miR-29c in the active TB group(561.63 ± 65.36, 281.85 ± 42.78) were higher than the healthy controls(260.74 ± 38.69, 128.21 ± 19.98), but lower than the LTBI group(2030.29 ± 321.68, 620.93 ± 79.14); expression of miR-29a in the healthy control group(913.95 ± 104.73) were higher than the active TB group(323.37 ± 54.38), but lower than the LTBI group(4782.13 ± 567.81).Level of IFN-γ showed significant differences among the three groups(P < 0.05): level of IFN-γ in the LTBI group(0.45 ± 0.09) were lower than the healthy controls(1.00), but higher than the active TB group(0.11 ± 0.03). The target genes of miR-29 family mainly existed in molecular function such as extracellular matrix structural constituent and transcription regulator activity.In KEGG pathway, the gene set mostly existed in signaling pathway such as Focal adhesion,ECM-receptor interaction and mTOR signaling pathway. The expression of miR-29 family was increased and target gene IFN-γ in CD4(+) T cells was decreased by latent and active pulmonary TB, which might play important role in alteration of signal pathway.