Inhibition of poly(ADP-ribose) Polymerase Interferes with Trypanosoma cruzi Infection and Proliferation of the Parasite

Abstract

Poly(ADP-ribosylation) is a post-translational covalent modification of proteins catalyzed by a family of enzymes termed poly(ADP-ribose) polymerases (PARPs). In the human genome, 17 different genes have been identified that encode members of the PARP superfamily. Poly (ADP-ribose) metabolism plays a role in a wide range of biological processes. In Trypanosoma cruzi, PARP enzyme appears to play a role in DNA repair mechanisms and may also be involved in controlling the different phases of cell growth. Here we describe the identification of potent inhibitors for T. cruzi PARP with a fluorescence-based activity assay. The inhibitors were also tested on T. cruzi epimastigotes, showing that they reduced ADP-ribose polymer formation in vivo. Notably, the identified inhibitors are able to reduce the growth rate of T. cruzi epimastigotes. The best inhibitor, Olaparib, is effective at nanomolar concentrations, making it an efficient chemical tool for chacterization of ADP-ribose metabolism in T. cruzi. PARP inhibition also decreases drastically the amount of amastigotes but interestingly has no effect on the amount of trypomastigotes in the cell culture. Knocking down human PARP-1 decreases both the amount of amastigotes and trypomastigotes in cell culture, indicating that the effect would be mainly due to inhibition of human PARP-1. The result suggests that the inhibition of PARP could be a potential way to interfere with T. cruzi infection.

NLRP3 Controls Trypanosoma cruzi Infection through a Caspase-1-Dependent IL-1R-Independent NO Production

“…Additionally, inos expression is significantly reduced in the presence of noncleavable PARP1 (D214N), compared to cleavable PARP1 (WT or enzymatically inactive) [64]. It was recently demonstrated that treatment with Olaparib (a pharmacological inhibitor of PARP-1 enzymatic activity) reduced T. cruzi replication in VERO cells [65]. However, the enzymatic activity of PARP-1 is not related to the role of cleaved PARP-1 in the regulation of chromatin condensation and access to transcription factors [60].…”

DNA Repair Pathways in Trypanosomatids: from DNA Repair to Drug Resistance

“…The T. cruzi PARP (TcPARP) poly(ADP-ribose) synthesis is activated by DNA strand breaks in vitro but also in vivo, as observed by the accumulation of PAR in the nuclei of T. cruzi epimastigotes. The activity is also inhibited by 3-aminobenzamide (61) but also by next-generation inhibitors such as olaparib (64). PARP activity is normally counterbalanced by a glycohydrolase activity, which hydrolyzes the polymers present on PARP, thereby allowing a new cycle of automodification.…”

“…Another way of taking advantage of the major role of PARP is to inhibit the protein in order to impair DNA repair mechanisms and therefore cell proliferation and drug resistance. Some PARP inhibitors were tested in T. cruzi, where PARP inhibition was effective on the amastigote but not the trypomastigote forms in cell culture (64). Pretreatment of parasites with the PARP inhibitor Olaparib decreased the number of intracellular amastigotes in infected cells.…”

Mammalian cellular culture models ofTrypanosoma cruziinfection: a review of the published literature

“…The T. cruzi strain most frequently employed was Tulahuen (TcVI; n  = 7), followed by the Y strain (TcII; n  = 4) and EP isolate (not classified into DTU; n  = 4). MOI, taken directly or calculated from all studies, ranged from 1 [35] to 50 parasites per host cell [34]. Parasite-cell incubation times were widely spread, from 2 h [19] to as long as 6 days [22].…”

“…When the MOI and FCS concentration were increased, infectivity was enhanced. In contrast, after 96 h of incubation, CL Brener-infected cells displayed 20.8% infection and less than three amastigotes per cell despite using a MOI which is 10 times higher than in experiments with EP [34]. Furthermore, infectivity in Vero cells with the EP isolate was higher than that seen with BEC isolate when using identical conditions [21].…”