Lipid profiling of Toxoplasma tachyzoites and the mouse host

Our understanding of lipids in Toxoplasma gondii and its host is incomplete. This study aimed to analyze phospholipids and sphingolipids in tachyzoites and mice. RH strain tachyzoites were cultured and purified. Models using BALB/c and C57BL/6 mice injected intraperitoneally (i.p.) with tachyzoites or carbon tetrachloride (CCl4) were developed and evaluated. Samples were analyzed with liquid chromatography-electrospray ionization tandem mass spectrometry (LC-MS-MS) method. In tachyzoites, phospholipids [phosphatidic acid (PA), phosphatidylcholine (PC), oxidized PC, phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylinositol (PI), and phosphatidylserine (PS)], lysophospholipids (LPLs)[lysophosphatidic acid (LPA), lysophosphatidylcholine (LPC), lysophosphatidylglycerol (LPG), lysophosphatidylinositol (LPI), and lysophosphatidylserine (LysoPS)], fatty acids (FAs) and their metabolites [arachidonic acid (20:4 AA), docosahexaenoic acid (22:6 DHA), prostaglandins, epoxyeicosatrienoic acid (EET), and dihydroxyeicosatrienoic acid (DHET)], were detected, suggesting de novo synthesis, PC oxidation, phospholipase action, and metabolism of FAs. Sphingolipids [ceramide (Cer) and sphingomyelin (SM)] were also detected in the tachyzoites. In mice, the histopathological changes in the tissues and plasma, are thought to be associated with changes in phospholipids and sphingolipids at the local and circulating levels. These changes create a parasitized microenvironment for Toxoplasma gondii. Current evidence suggests that 16:0 20:4 PC, 16:0 22:6 PC, 18:0 22:6 PE, 16:0 22:6 PI, 22:6 DHA, d18:1 23:0 SM, 16:0 Cer and 16:0 cerebroside (16:0 Cb) are important as potential biomarkers and targets of Toxoplasma gondii infection. Overall, the comprehensive and comparative profiling of lipids in tachyzoites and the mouse host has been achieved, contributing to the understanding of Toxoplasma lipid biology and the exploration of strategies against toxoplasmosis.