Summary
A bioRxiv preprint reports a pooled CRISPRi screen that measured 1,326 pairwise genetic interactions among 51 Mycobacterium tuberculosis drug-target genes. Follow-up experiments found drug synergies involving ATP synthase targets and reported that inhibiting Pks13 potentiated antitubercular agents.
A pooled CRISPR interference (CRISPRi) screen has mapped 1,326 pairwise genetic interactions among 51 priority drug-target genes in Mycobacterium tuberculosis, according to a bioRxiv preprint. The researchers report that synergistic interactions were widespread, and that laboratory tests linked some genetic interactions to drug combinations with greater combined efficacy. They also found that inhibiting the target Pks13 potentiated several antitubercular agents and restored drug susceptibility in an SQ109-resistant bacterial mutant.
The work uses gene interactions as a way to search for potential drug synergies. Finding useful tuberculosis drug combinations by testing compounds directly can be resource-intensive and is limited to available compounds and the pathways they target. The researchers’ approach instead screens pairs of genes, potentially revealing target combinations before a matching pair of drugs is available.
How the screen identified candidate combinations
CRISPRi reduces the activity of selected genes. In a pooled screen, the researchers assessed pairs of gene targets together, using the effects of combined gene suppression as a proxy for how drugs aimed at those targets might interact. In the study’s terminology, synergy means that the combined effect is greater than the sum of the effects of each agent alone.
The screen covered 51 genes encoding priority drug targets and measured 1,326 pairwise interactions. Many of the reported synergies involved targets in different functional pathways, suggesting that useful combinations may not be limited to drugs acting on closely related parts of the bacterium.
A genetic interaction is not itself a drug combination. The researchers experimentally tested interactions involving ATP synthase and report that these corresponded to drug-drug synergies. They also examined polyketide synthase 13 (Pks13), an enzyme involved in mycolic acid synthesis. Chemical inhibition of Pks13 potentiated diverse antitubercular agents in the experiments and restored susceptibility in a mutant resistant to SQ109.
What the findings could enable
The results point to pooled CRISPRi as a scalable way to prioritise combinations of tuberculosis drug targets for further investigation. Screening targets across different pathways could expand the search beyond combinations of existing compounds, while the Pks13 result suggests that one target may enhance the activity of drugs aimed at multiple pathways.
This is laboratory research reported in a preprint, not a clinical study. The findings identify candidate interactions for follow-up; they do not establish that these combinations are effective treatments for people with tuberculosis.