Biology subjects

Hanna, J. C.

Publications and source records attributed to Hanna, J. C..

3 recordsLinked to original sources

bioRxiv2026

Copper transport is required for metabolism and persistence of Toxoplasma gondii

Copper is a conserved cofactor, required for essential processes including aerobic respiration. Pathogens subvert host copper; however the mechanisms of copper uptake are not well understood. Here, we identify and validate two copper transporters of Toxoplasma gondii and determine the role of copper in parasite metabolism and pathogenesis. We show that Ctr1 is required for copper uptake. Deletion leads to undetectable parasite-associated copper, a significant growth defect and a metabolic shift from mitochondrial respiration with to glycolysis. Absence of Crt1 was fully and rapidly rescued by exogenous copper, which we believe is transported through the lower-affinity transporter Ctr2. Ctr2 is dispensable in rapid growth, however, has a role in parasite persistence in chronic infection, both in vitro and in vivo. Together, these findings reveal for the first time a critical role for copper uptake in shaping metabolic plasticity, and highlights the importance of nutrient availability in regulating apicomplexan metabolism.

cell biology↗

bioRxiv2025

Global translational and metabolic remodelling during iron deprivation in Toxoplasma gondii

Iron is required to support essential cellular processes. Due to diverse and dynamic host environments, the obligate intracellular parasite Toxoplasma gondii must adapt to iron limited conditions. To investigate the adaptations critical to parasite survival under these conditions, we conducted proteomic and metabolomic profiling of Toxoplasma cultured in iron depleted conditions. We find that iron depletion results in remodelling of the parasite proteome and triggers swift translational repression. This occurs prior to downregulation of the iron-regulated translation factor ABCE1, indicating an upstream, ABCE1-independent mechanism. In the context of repressed translation, we also observe a significant rewiring of energy metabolism. Iron depleted Toxoplasma have altered mitochondrial morphology and a profound reduction in mitochondrial respiration. Untargeted metabolomic analysis revealed tricarboxylic acid cycle (TCA) cycle dysregulation, characterised by accumulation of citrate and fumarate, both substrates of iron-dependent TCA cycle enzymes, and accumulation of glycolytic intermediates. We found iron deprived parasites continue to take up glucose and maintain glycolytic output, comparable to iron replete conditions. Limiting glucose availability either in culture media or by genetic ablation of glucose uptake caused a significant increase in sensitivity to iron restriction. Conversely, limitation of mitochondrially metabolised glutamine improved parasite fitness in iron depleted conditions. Together, our results establish iron as a key regulator of parasite translation and metabolic flexibility and demonstrate carbon source availability as important in Toxoplasma adaptation to iron deprivation. ImportanceThis study determines the effects of iron deprivation on the parasite Toxoplasma gondii. Using proteomics and metabolomics, we reveal iron as a novel regulator of both translation and energy metabolism in Toxoplasma, underpinning the importance of this nutrient for essential cellular processes. We find that iron depletion introduces a metabolic bottleneck whereby parasites are dependent on glucose as their major carbon source. By modulating the parasites metabolism by altering carbon source availability, we identify nutrient conditions that improve parasite survival under iron restriction. These data reveal a key role for adaptive plasticity of Toxoplasma central carbon metabolism to drive survival under iron limited conditions. Understanding the interactions between parasite nutrient availability and metabolism allows us both to map the metabolic flexibility of these parasites, and to identify potential vulnerabilities.

microbiology↗

bioRxiv2024

Cryptosporidium Oocyst Wall Proteins are true oocyst wall proteins, with COWP8 functioning to hold the inner and outer layers of the oocyst wall together

Cryptosporidiosis is a significant cause of diarrhoeal disease contributing to substantial morbidity and mortality for the immunocompromised and for young children, especially those who are malnourished. There are no vaccines available and no effective treatments for these patients. Another challenge is that Cryptosporidia are waterborne and resistant to common water treatments including chlorination. Cryptosporidia are transmitted as an oocyst that is made up of a hardy oocyst wall that protects four parasites. Little is understood about how the oocyst is constructed, its composition, and the how it resists chlorination. A family of predicted Cryptosporidium Oocyst Wall Proteins (COWPs) was identified from the genome. Using a genetic approach, we confirm that all members of the COWP family localise to the oocyst wall. Our studies indicate that COWP2, 3 and 4 localise specifically to the oocyst "suture", a zipper-like structure on the oocyst wall from which parasites emerge during infection. In parasites lacking COWP8, we observe that the inner and outer layers of the oocyst wall are no longer associated suggesting a role for COWP8 in oocyst wall morphology. Despite loss of COWP8, these transgenic parasites are viable, unchanged in mechanical strength, and retain resistance to chlorination. This work sets the foundation for future exploration of Cryptosporidium transmission.

microbiology↗