Date of Award

2025-12-01

Degree Name

Doctor of Philosophy

Department

Biological Sciences

Advisor(s)

Rosa A. Maldonado

Second Advisor

Igor C. Almeida

Abstract

Chagas disease remains one of the most persistent and neglected parasitic infections in the Americas, advancing silently through the intracellular replication of Trypanosoma cruzi amastigotes and the invasive spread of trypomastigotes. The survival of the parasite is critically reliant on protein N-myristoylation, a lipid modification catalyzed by N-myristoyltransferase (NMT). This dissertation aims to advance beyond prior studies by systematically investigating NMT inhibition across multiple biological levels, spanning from the characterization of the purified enzyme, through cellular infection models, to the global proteomic remodeling induced within the parasite, thereby evaluating TcNMT as a potential therapeutic vulnerability in T.cruzi.Recombinant TcNMT was expressed, purified, and kinetically profiled, confirming its canonical catalytic behavior and sensitivity to the benchmark inhibitor DDD85646. Cellular assays in human cardiomyocytes demonstrated that NMT inhibition reduced intracellular infection, although the compound's host toxicity narrowed its therapeutic margin. Proteomic profiling revealed that the effects of NMT inhibition were distinct and dependent on the parasite's developmental stage. Amastigotes showed disruptions in vesicular trafficking and lipid metabolism, while trypomastigotes suffered losses in flagellar scaffolding proteins such as FcCaBP and CAP5.5, impairing the machinery of reinvasion. Host proteomes, in contrast, remained comparatively stable. Collectively, these findings position TcNMT not merely as an essential enzyme, but as a central regulatory node in T. cruzi biology. The therapeutic implication is that while DDD85646 itself is unsuitable as a scaffold, the target it strikes remains a tractable and promising vulnerability. By revealing stage-specific weak points in replication and motility, this work provides a framework for the development of new inhibitors, rational combination regimens, or other molecular strategies such as metronomic therapy inspired by oncology. Ultimately, strategies that weaken parasites at their replicative and motile stages may delay the cycles of reinfection and tissue damage that underlie myocardial inflammation and the hypertrophy characteristic of chronic Chagas disease. In this sense, TcNMT inhibition is not a closed story but an open one, pointing toward future interventions that could change the way Chagas disease is treated.

Language

en

Provenance

Received from ProQuest

File Size

118 p.

File Format

application/pdf

Rights Holder

Diana Citlali Gonzalez Garci­a

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