Troglitazone Reduction of Intracellular <i>Mycobacterium tuberculosis</i> Survival Via Macrophage Autophagy Through LKB1-AMPKα Signaling

Tuberculosis caused by Mycobacterium tuberculosis (Mtb), results in significant disease and death worldwide. Host-directed therapy, including conventional drugs, is a promising antituberculosis strategy that shows synergistic antibacterial effects when combined with antituberculosis drugs. Here, the mycobactericidal effect of 3 antidiabetic drugs was examined. Of these, only troglitazone (Trog) enhanced the antimycobacterial effect in vitro and in vivo. This was due to Trog-mediated autophagy activation. Moreover, a knock-down experiment revealed that Trog activated autophagy and exhibited antimycobacterial activity through the serine/threonine-protein kinase STK11 (LKB1)-5'-AMP-activated protein kinase (AMPK) signaling pathway. Molecular docking and coimmunoprecipitation experiments demonstrated that Trog promoted LKB1 phosphorylation and activation by targeting STE20-related kinase adapter protein alpha (STRADA). Finally, we found that Trog inhibited the intracellular survival of clinical isoniazid-resistant Mtb, and the combination of Trog and isoniazid showed additive antibacterial effects against Mtb H37Rv. Taken together, antidiabetic Trog may be repurposed as a candidate for host-directed therapy and combined with first-line antituberculosis drugs.