Abstract:

Objective To investigate the regulation role of dormancy survival regulator（DosR） antigen Rv2626c expressed in latent tuberculosis infection（LTBI） in the activation of macrophage and the regulation influence of long non-coding RNA（lncRNA） MacORIS. Methods Human acute monocytic leukemia cell line THP-1 cells were differentiated into macrophage and categorized into 4 groups based on different transfections：negative control（NC） group [transfected with NC-small interfering RNA（siRNA） for 24 h] and MacORIS-siRNA group [transfected with MacORIS-siRNA for 24 h]，NC-siRNA+recombinant protein Rv2626c（rRv2626c） group [transfected with NC-siRNA for 24 h，then stimulated with 3 μg·mL^-1 rRv2626c for 24 h]，MacORIS-siRNA+rRv2626c group [transfected with MacORIS-siRNA for 24 h，then stimulated with 3 μg·mL^-1 rRv2626c for 24 h]. The expression of lncRNA MacORIS，Toll-like receptor（TLR）2，TLR4，surface co-stimulatory molecules（CD80，CD86，CD163，CD206），indoleamine 2，3-dioxygenase 1（IDO1），tumor necrosis factor-alpha（TNF-α），interleukin（IL）-6，IL-8 and IL-1β were determined. The competitive endogenous RNA（ceRNA） networks of lncRNA MacORIS were predicted and constructed by bioinformatics methods，and the potential target microRNA of lncRNA MacORIS was verified. Results The rRv2626c effectively promoted the upregulation of lncRNA MacORIS and IDO1 in macrophage（P<0.05）. The rRv2626c induced the expression of TLR2 in THP-1 cells，which was dependent on lncRNA MacORIS（P<0.05）. Furthermore，rRv2626c depended on lncRNA MacORIS to upregulate the expressions of CD80，CD86，TNF-α and IL-1β in macrophage（P<0.001）. Compared to the NC group，the relative expression levels of miR-141-3p，miR-150-5p，miR-33-5p，miR-200-3p and miR-203-3p in the MacORIS-siRNA group were increased（P<0.05）. Conclusions The rRv2626c promotes the polarization of macrophage toward M1 phenotype，and it enhances the expression of TLR2 and inflammatory factors，which depends on lncRNA MacORIS. The lncRNA MacORIS could negatively regulate the expression of miR-141-3p，miR-150-5p，miR-33-5p，miR-200-3p and miR-203-3p.

Key words: Long non-coding RNA MacORIS, Rv2626c, Macrophage, Latent tuberculosis infection