2-Aminopyridine Analogs Inhibit Both Enzymes of the Glyoxylate Shunt in Pseudomonas aeruginosa

Abstract

Pseudomonas aeruginosa is an opportunistic pathogen responsible for many hospital-acquired infections. P. aeruginosa can thrive in diverse infection scenarios by rewiring its central metabolism. An example of this is the production of biomass from C2 nutrient sources such as acetate via the glyoxylate shunt when glucose is not available. The glyoxylate shunt is comprised of two enzymes, isocitrate lyase (ICL) and malate synthase G (MS), and flux through the shunt is essential for the survival of the organism in mammalian systems. In this study, we characterized the mode of action and cytotoxicity of structural analogs of 2-aminopyridines, which have been identified by earlier work as being inhibitory to both shunt enzymes. Two of these analogs were able to inhibit ICL and MS in vitro and prevented growth of P. aeruginosa on acetate (indicating cell permeability). Moreover, the compounds exerted negligible cytotoxicity against three human cell lines and showed promising in vitro drug metabolism and safety profiles. Isothermal titration calorimetry was used to confirm binding of one of the analogs to ICL and MS, and the mode of enzyme inhibition was determined. Our data suggest that these 2-aminopyridine analogs have potential as anti-pseudomonal agents.

Small molecule resensitizesSalmonellato itaconate and decreases bacterial proliferation in macrophages

“…[3][4][5][6] Targeting this pathway is expected to only affect the pathogenic bacteria in nutrient-starved milieus, such as within the macrophage, while the commensal bacteria, often found in nutrient-rich locations, should remain unaffected, thus treating infections with minimal effect on the beneficial microflora. Whereas several research groups have attempted to target Icl for the development of antibiotics, [7][8][9][10][11][12][13][14] such inhibitors have yet to make it to the market.…”

Investigating the Role of Metabolism for Antibiotic Combination Therapies in Pseudomonas aeruginosa

“… 32 SB002 was then identified, which has exhibited the potent inhibition of malate synthase and isocitrate lyase, which are both enzymes comprising the glyoxylate shunt pathway ( Figure 1 ). 33 Subsequently, SB002 was synthesized in one step according to the reported procedure (see the Supporting Information ) and was tested in a checkerboard assay with 2 ( Figure 2 D). To our surprise, SB002 diminished the inhibitory activity of 2 in a concentration-dependent manner ( Figure 2 D).…”