RESUMEN
Objective To determine the effect of Mycobacterium tuberculosis spp. inducing transformation of THP-1 cells to epithelioid cells (EC) and the involved signaling pathways and their regulations. Methods THP-1 cells infection models respectively infected with M. tuberculosis strains H37Rv, bovis and phlei were established. Indirect immunofluorescent staining assays were used to detect the expressions of monocyte/macrophage differentiation antigen CD115 and EC differentiation antigen CD82 of the THP-1 cells before or after infection. By Sandwich ELISA Kits, the phosphorylation levels of p38MAPK, Akt1 and STAT3 of the THP-1 cells before or after infection were measured. The alterations of CD115 and CD82 expression levels were examined when the associated signaling pathways were blocked with specific blocking agents. Results CD115 expression was weakened and CD82 expression was strongly increased in all the THP-1 cells infected with the three strains. A temporal up-regulation of the p38MAPK phoshporylation level but no obvious alteration of Akt and STAT3 phosphorylation levels after THP-1 cells infected by strain H37Rv or bovis. The THP-1 cells infected with anyone of the three strains continuously expressed CD115 after MAPK, PI3K/Akt or JAK/STAT of the cells was blocked. Although JAK/STAT was blocked, the THP-1 cells respectively infected with the three different strains still expressed CD82. However, CD82 expressed in THP-1 cells infected by the strain H37Rv or bovis was disappeared when p38MAPK and PI3K/Akt pathways of the cells were blocked. Conclusion Strain H37Rv and bovis can induce the infected THP-1 cells transforming to EC and p38MAPK and PI3K/Akt signaling pathways participate and regulate the transformation procedure. Of the two signaling pathways p38MAPK seems to be more important.