Biological insights into the parasitic nematode Heligmosomoides bakeri from bulk and single-cell transcriptomics
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2023-12-05
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Abstract
Heligmosomoides bakeri, a parasitic nematode (roundworm) of mice, is closely related to economically important parasites of livestock and the hookworm parasites of humans. As a murine parasite it is more amenable to being maintained and manipulated in a controlled laboratory environment than its relatives. The worm enters its host during its third larval stage and develops through another larval stage into adults that reside in the lumen of the small intestine to mate and lay their eggs. Unravelling these processes and other processes critical to H. bakeri survival could reveal new targets to use for drug discovery for controlling this group of parasites as well as refine previous predictions of immunomodulatory molecules, which have therapeutic potential. My thesis aims to describe the gene expression of H. bakeri during the parasitic phase of its lifecycle. I first used RNA sequencing to investigate how the (whole worm) expression of genes varies across the parasite’s infection. Using differential gene expression analyses I identified genes important for development and genes important for the males vs the females. I also uncovered evidence of an increased importance for anaerobic respiration in the adults compared to the larvae and hypothesize that aerobic conditions are important for the critical developmental processes of molting and cuticle synthesis. I then analyzed single-cell RNA-seq data from young adult male and female worms. Leveraging cell type markers from the model nematode C. elegans allowed me to putatively identify gamete, embryo, intestine, hypodermis, neuron, and muscle cells. The resulting cluster expression profiles can guide investigations into tissue-specific aspects of the adult worms. Putative intestinal transcription profiles suggest compartmentalization of function along the anterior-posterior axis of the worms, with an emphasis on protein synthesis in the anterior portion, as has been observed in other worms. Embryonic profiles are noticeably different from C. elegans embryogenesis, particularly with respect to paternal contributions to the early embryo. Overall, these datasets extend our understanding of how H. bakeri lives as a parasite and provide a public resource for further investigation into genes of interest. They also lay the groundwork for more comprehensive comparisons among the phylum Nematoda.
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Pollo, S. M. J. (2023). Biological insights into the parasitic nematode Heligmosomoides bakeri from bulk and single-cell transcriptomics (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.