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IspH inhibitors kill Gram-negative bacteria and mobilize immune clearance.

ABSTRACT: Isoprenoids are vital for all organisms, in which they maintain membrane stability and support core functions such as respiration¹. IspH, an enzyme in the methyl erythritol phosphate pathway of isoprenoid synthesis, is essential for Gram-negative bacteria, mycobacteria and apicomplexans^2,3. Its substrate, (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), is not produced in metazoans, and in humans and other primates it activates cytotoxic Vγ9Vδ2 T cells at extremely low concentrations^4-6. Here we describe a class of IspH inhibitors and refine their potency to nanomolar levels through structure-guided analogue design. After modification of these compounds into prodrugs for delivery into bacteria, we show that they kill clinical isolates of several multidrug-resistant bacteria-including those from the genera Acinetobacter, Pseudomonas, Klebsiella, Enterobacter, Vibrio, Shigella, Salmonella, Yersinia, Mycobacterium and Bacillus-yet are relatively non-toxic to mammalian cells. Proteomic analysis reveals that bacteria treated with these prodrugs resemble those after conditional IspH knockdown. Notably, these prodrugs also induce the expansion and activation of human Vγ9Vδ2 T cells in a humanized mouse model of bacterial infection. The prodrugs we describe here synergize the direct killing of bacteria with a simultaneous rapid immune response by cytotoxic γδ T cells, which may limit the increase of antibiotic-resistant bacterial populations.

SUBMITTER: Singh KS

PROVIDER: S-EPMC8776033 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Isoprenoids are vital to all organisms in supporting core functions of life, like respiration and membrane stability. IspH, an enzyme in the methyl erythritol phosphate pathway of isoprenoid synthesis, is essential to gram-negative bacteria, mycobacteria and apicomplexans. The IspH substrate, HMBPP, is not produced in humans and other metazoans and activates cytotoxic T-cells in humans and primates at extremely low concentrations. We describe novel IspH inhibitors and through structure-guided analog design, refine their potency to nanomolar levels. We have modified these into prodrugs for delivery into bacteria and report that they kill clinical isolates of several multidrug resistant bacterial species such as Acinetobacter, Pseudomonas, Klebsiella, Enterobacter, Vibrio, Shigella, Salmonella, Yersinia, Mycobacterium and Bacillus, while being relatively non-toxic to mammalian cells. Proteomic analysis reveals that bacteria treated with prodrugs resemble those with conditional IspH knockdown. Notably, these prodrugs also cause expansion and activation of human T-cells in a humanized mouse model of bacterial infection. These IspH prodrugs synergize direct antibiotic killing with a simultaneous rapid immune response by cytotoxic T-cells, thus inhibiting the rise of antibiotic resistant bacterial populations.

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