Mycobacterium tuberculosis small RNA MTS1338 is required for bacterial virulence and regulates the expression of an immune-evasion molecules

Bacterial small non-coding RNAs play an essential role in adaptation to stresses. M. tuberculosis small RNA MTS1338 was shown to contribute to successful persistence of mycobacteria within host cells. In this study, we expressed MTS1338 in Mycobacterium smegmatis, and studied transcriptomic and proteomic changes in the recombinant strain. We found that MTS1338 expression resulted to DosR regulon activation, metabolic changes characteristic for hypoxia, mycolic acids synthesis, as well as rearrangement of iron metabolism. These metabolic changes slow down bacterial growth in vitro, provide an increase of non-pathogenic M.smegmatis survival in the infected THP-1macrophages, and also influence phagosome maturation. THP-1 Macrophages were infected with two strains of M. smegmatis. One strain contaned a vector that expresses M.tuberculosis small non-coding RNA MTS1338 (pMV_MTS1338) and other strain was a control and contained an empty vector (pMV_Empty). In each group, three independent biological samples were sequenced.