Pharmacological investigation of Trypanosoma cruzi phosphodiesterases as drug targets. Insight into target vulnerability.

SCHOIJET, ALEJANDRA C.; PREGO, ALEJO; VILCHEZ LARREA, SALOMÉ C.; LLANOS, MANUEL A.; ALBERCA, LUCAS N.; BELLERA, CAROLINA L.; GAVENET, LUCIANA; TALEVI, ALAN; ALONSO, GUILLERMO D.

Mendoza

Congreso; XI Congreso de la Sociedad Argentina de Protozoología; 2022

Sociedad Argentina de Protozoología

The intracellular cAMP and cGMP levels are regulated by cyclic nucleotide phosphodiesterases(PDEs), a group of specific cyclic nucleotide-degrading enzymes involved in the control ofhomeostasis. It is long been self-evident that increased knowledge of cyclic nucleotide signalingpathways can lead to the development of therapeutic agents against human diseases. Thekinetoplastid PDEs are highly similar to most of the human homologs, which justifies thepotential repurposing of PDE inhibitors as potential antiparasitic agents. Also, these PDEs arehighly amenable to selective inhibition, due to small differences in their binding pockets.Correlating target engagement with in vivo drug activity remains a central challenge in effortsto improve the efficiency of drug treatment and discovery. Among other methods, cell-basedwashout experiments, in which the phenotypic consequences of target engagement areevaluated once drug is “removed” from the system, can provide direct insight into targetvulnerability.In this work, washout experiments were performed to test the effect of three commercial PDEinhibitors: Rolipram, Zaprinast and Vinpocetine. Post-washout infection inhibition wasmaintained for all inhibitors, but Vinpocetine showed the largest detrimental effect on in vitroT. cruzi infection experiments. This inhibitor also proved to be effective in trypomastigotes andamastigotes. As additional experiments in order to support target validation, we tested twoother compounds from in silico studies, Terameprocol and Lasalocid. Both compounds showedto be effective at low concentrations in the amastigote stage in our experimental model. Finally,we evaluated the effect of both drugs on enzymatic activity using TcrPDEB2 and TcrPDECrecombinant T. cruzi enzymes. Both compounds showed activity inhibition at lowconcentrations. In summary, these results highlight the potential of PDEs as targets againstChagas´ disease.