Treatment of Mycobacterium tuberculosis infected macrophages with Rifabutin loaded β-glucan microparticles induces macroautophagy mediated bacillary killing

Abstract This study aims to assess the therapeutic efficacy of Rifabutin-loaded β-glucan particles (DYDGP) in targeting Mycobacterium tuberculosis (M.tb.) within host macrophage cells. Drug-loaded β-glucan microparticles were prepared using rifabutin for evaluating their therapeutic potential against in-vitro M.tb. infection in host macrophage cells. Our results demonstrate that DYDGP significantly enhances intracellular ROS generation at 30 minutes and 24 hours post-treatment compared to blank (YDGP) particles in the presence of NOX-2 inhibitors. Additionally, DYDGP promotes phago-lysosomal maturation and exhibits better cytoprotective function within M.tb. infected macrophages up to 24 hours post-treatment. Furthermore, our study indicates that DYDGP has the potential to induce autophagy within M.tb. infected macrophages, as evidenced by dansylcadvarine and immunofluorescence studies, along with LC-3 and NOX-2 protein expression analyses. Enhanced immunotherapeutic efficacy is crucial for combating M.tb, including multidrug-resistant (MDR) strains, within host macrophage cells. Colony forming unit studies confirm that DYDGP particles exhibit better immunotherapeutic potential compared to blank and pure drugs, suggesting they could serve as a promising alternative for host-directed adjunct therapies against M.tb. infections. These findings highlight the potential of DYDGP in improving therapeutic outcomes and combating drug-resistant M.tb. strains within host cells, contributing to the development of effective immunotherapeutic strategies against tuberculosis.