Figure 2.

Expression and regulation of MMPs in TB. In Mtb infection, there is upregulation of many MMPs which are contributing to TB pathology. The expression and secretion of MMPs are strictly regulated as excess of these enzymes may cause tissue destruction. Many studies have investigated these signalling pathways. P38/COXII/PGE2/cAMP is well‐established signalling cascade involved in the regulation of MMP‐1. In a recent study, IL‐17‐mediated regulation of MMP‐3 was dependent on MAPK. In addition, TNF‐α and HDAC1 can also regulate MMP‐1 and MMP‐9, and MMP‐1 and MMP‐3, respectively. As the excess of these MMPs may be detrimental for host and may exaggerate the TB pathology, therefore, inhibition of these signalling pathways may provide a new avenue for host‐directed therapy in TB