Nika Ten (Amsterdam UMC)

Summary of presentation:
The ability of Mycobacterium tuberculosis (Mtb) to evade the immune system and exploit it to its advantage has been extensively studied over the past decades. Mtb can persist within macrophages, avoiding degradation, and strategically escape by inducing host cell death at the most advantageous moments. Host-directed therapies, given in addition to antibiotics, aims to improve the host’s immune response and enhance the body’s natural ability to fight infections. Here, we performed a genome-wide CRISPR-Cas9 knockout screen in Mtb-infected THP-1 macrophages to identify host genes that regulate infection-associated macrophage death. A pooled Cas9-expressing THP-1 population was transduced with a lentiviral sgRNA library, infected with Mtb, and screened by negative selection to identify knockouts associated with reduced macrophage survival during infection. Follow-up validation confirmed MTA2, FAM49B, ARID3A, and INPP5D as modulators of macrophage viability, and individual gene knockouts increased infection-associated cell death. The knockouts showed altered bacterial uptake and intracellular burden, suggesting involvement of host cytoskeletal remodeling. RNA-seq revealed that ARID3A and MTA2 knockouts show differential expression of genes involved in extracellular matrix and structural organization, supported by an extracellular matrix degradation assay. Finally, availability of pharmacological activation of INPP5D opens up a potential host-directed strategy to improve macrophage viability during infection. Together, our study identifies four host genes that influence macrophage survival during Mtb infection and highlights candidate pathways for host-directed therapeutic intervention.