Biology subjects

Gallego-Lopez, G. M.

Publications and source records attributed to Gallego-Lopez, G. M..

2 recordsLinked to original sources

bioRxiv2023

Metabolic changes to host cells with Toxoplasma gondii infection

Toxoplasma gondii, the causative agent of toxoplasmosis, is an obligate intracellular parasite that infects warm-blooded vertebrates across the world. In humans, seropositivity rates of T. gondii range from 10% to 90%. Despite its prevalence, few studies address how T. gondii infection changes the metabolism of host cells. Here, we investigate how T. gondii manipulates the host cell metabolic environment by monitoring metabolic response over time using non-invasive autofluorescence lifetime imaging of single cells, seahorse metabolic flux analysis, reactive oxygen species (ROS) production, and metabolomics. Autofluorescence lifetime imaging indicates that infected host cells become more oxidized and have an increased proportion of bound NAD(P)H with infection. These findings are consistent with changes in mitochondrial and glycolytic function, decrease of intracellular glucose, fluctuations in lactate and ROS production in infected cells over time. We also examined changes associated with the pre-invasion "kiss and spit" process using autofluorescence lifetime imaging, which similarly showed a more oxidized host cell with an increased proportion of bound NAD(P)H over 48 hours. Glucose metabolic flux analysis indicated that these changes are driven by NADH and NADP+ in T. gondii infection. In sum, metabolic changes in host cells with T. gondii infection were similar during full infection, and kiss and spit. Autofluorescence lifetime imaging can non-invasively monitor metabolic changes in host cells over a microbial infection time-course.

microbiology↗

bioRxiv2022

Kiss and spit metabolomics highlights the role of the host cN-II enzyme on purine metabolism during pathogen infection

Intracellular pathogens are auxotrophic for many metabolites and must rely on the host. While this reliance is well established, how pathogens manipulate host metabolism to their benefit is not understood. For intracellular pathogens, distinguishing the origin of the metabolite as host- or pathogen-derived is challenging. The obligate intracellular parasite Toxoplasma gondii alters the host cell by a pre-invasion process known as "kiss and spit", where the contents of the parasite rhoptry organelles are secreted into the host cytoplasm before invasion occurs. This separation of microbe from the host offers a rare opportunity to demonstrate pathogen manipulation of the host. Using mass spectrometry-based metabolomics, we determined that kiss and spit changed host metabolites in nucleotide synthesis, the pentose phosphate pathway, glycolysis, and amino acid synthesis. An increase in 2,3-bisphosphoglycerate (2,3-BPG) abundance led us to hypothesize that high levels of host 2,3-BPG contribute to the activation of host cytosolic nucleosidase II (cN-II) to alter purine availability. Treatment with the cN-II inhibitor fludarabine and a cell line with a cN-II genetic knockout reduced T. gondii growth. Our results demonstrate that T. gondii rhoptry contents discharged during kiss and spit remodel host metabolism. They also suggest that T. gondii manipulates the host cN-II enzyme to acquire its necessary purine metabolites.

microbiology↗