Abstract
Obligate intracellular apicomplexan parasites are considered as deficient in cholesterol biosynthesis and scavenge cholesterol from their host cell in a parasite-specific manner. Compared to fast proliferating apicomplexan species producing low numbers of merozoites per host cell, (e. g. Toxoplasma gondii), the macromeront-forming protozoa Eimeria bovis is in extraordinary need for cholesterol for offspring production (≥ 170,000 merozoites I/macromeront). Interestingly, optimized in vitro E. bovis merozoite I production occurs under low foetal calf serum (FCS, 1.2%) supplementation. To analyze the impact of extensive E. bovis proliferation on host cellular sterol metabolism we here compared the sterol profiles of E. bovis-infected primary endothelial host cells grown under optimized (1.2% FCS) and non-optimized (10% FCS) cell culture conditions. Therefore, several sterols indicating endogenous de novo cholesterol synthesis, cholesterol conversion and sterol uptake (phytosterols) were analyzed via GC–MS-based approaches. Overall, significantly enhanced levels of phytosterols were detected in both FCS conditions indicating infection-triggered sterol uptake from extracellular sources as a major pathway of sterol acquisition. Interestingly, a simultaneous induction of endogenous cholesterol synthesis based on increased levels of distinct cholesterol precursors was only observed in case of optimized parasite proliferation indicating a parasite proliferation-dependent effect. Considering side-chain oxysterols, 25 hydroxycholesterol levels were selectively found increased in E. bovis-infected host cells, while 24 hydroxycholesterol and 27 hydroxycholesterol contents were not significantly altered by infection. Exogenous treatments with 25 hydroxycholesterol, 27 hydroxycholesterol, and 7 ketocholesterol revealed significant adverse effects on E. bovis intracellular development. Thus, the number and size of developing macromeronts and merozoite I production was significantly reduced indicating that these oxysterols bear direct or indirect antiparasitic properties. Overall, the current data indicate parasite-driven changes in the host cellular sterol profile reflecting the huge demand of E. bovis for cholesterol during macromeront formation and its versatility in the acquisition of cholesterol sources.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
