Unveiling the Role of PHF20 in TBC1D4-Mediated Glucose Uptake During Toxoplasma gondii Infection

Abstract

BackgroundToxoplasma gondii relies on host cell nutrients, especially glucose, to support its intracellular growth. However, the mechanisms by which it enhances host glucose metabolism remain incompletely understood. MethodsWe used fluorescence-based glucose uptake assays, flow cytometry, metabolic flux analysis, and gene silencing in ARPE-19 cells, along with transgenic mouse models, to explore how T. gondii manipulates host glucose utilization and whether this promotes parasite proliferation. ResultsT. gondii infection significantly enhanced host glucose uptake in a dose-dependent manner and promoted GLUT4 translocation to the plasma membrane. Notably, extracellular acidification rate (ECAR) assays demonstrated a marked increase in glycolytic activity following infection. Mechanistically, we identified that the PI3K/AKT signaling pathway mediates the phosphorylation and transcriptional upregulation of TBC1D4, a Rab-GAP protein essential for GLUT4 trafficking. Genetic silencing of TBC1D4 impaired both glucose uptake and parasite replication. Furthermore, we uncovered a regulatory mechanism involving AKT-dependent nuclear signaling that modulates TBC1D4 transcription. In vivo experiments using Phf20 transgenic mice confirmed increased susceptibility to T. gondii and elevated glucose metabolic responses. ConclusionsOur study reveals that T. gondii hijacks a host PI3K/AKT-TBC1D4 axis to enhance glucose uptake and glycolysis, thereby ensuring metabolic support for its proliferation. These findings highlight host glucose metabolism as a potential therapeutic target for controlling toxoplasmosis.