Fig. 5: Proposed mechanism of action of SQ109.

SQ109 has a dual mode of action, with direct bactericidal activity and immunomodulatory properties. SQ109 activates the MAPK and JNK pathways in macrophages, leading to the induction of pro-inflammatory M1-type macrophage responses and apoptosis. Pro-inflammatory responses further modulate the dynamics of T helper cells, which imparts further protection to the host. SQ109 induces production of iNOS, which further mediates the killing of intracellular mycobacteria.