Characterization of the Trypanosoma cruzi flagellum in replicative stages

Abstract

Trypanosoma cruzi is a kinetoplastid parasite which causes Chagas disease in humans. Chagas disease is a neglected tropical disease, which can lead to chronic cardiac and gastrointestinal disorders. Few treatments are available to these patients, and to develop better drugs, more must be understood about parasite-host interactions. Throughout its life cycle, T. cruzi maintains a single flagellum, which interacts with the different host environments it experiences across each developmental stage. Most recently, an interaction between the flagellum of the intracellular mammalian stage, the amastigote, and the host mitochondria was discovered; however, the purpose for this interaction was unknown. Based on this observation, we became interested in understanding more about the flagellum of T. cruzi. In this dissertation, we endeavored to better characterize the T. cruzi flagellum in its replicative stages. In Chapter One, a review of what is currently known about T. cruzi and other kinetoplastid flagella is presented. The findings of this dissertation research are also outlined. In Chapter Two, the amastigote flagellar beat was discovered and described for the first time. We additionally characterized the amastigote flagellar beat response to small molecule modulators of common second messenger pathways. In Chapter Three, proteomic analysis of the amastigote and epimastigote flagellum is described. Proximity labeling was used to identify hundreds of proteins in the flagellum of these two life stages, of which many are conserved flagellar proteins from other kinetoplastids. Approximately twenty percent of these proteins are restricted to the T. cruzi lineage, opening the door to investigate novel areas in T. cruzi flagellar biology. In Chapter Four, the implications of the work presented here are discussed and future studies to answer open questions in the field are proposed. Additionally, the overarching question of this dissertation, the role of the amastigote flagellum, is addressed. Through this work, tools have been created to study the movement of the amastigote flagellum and a large proteomic dataset has been shared with the community. It is our intention that these resources be used to continue to study T. cruzi flagellar-host interactions.