In Vitro Inhibition of Cryptosporidium parvum Infection by the Olive Oil Component Oleocanthal

Human cryptosporidiosis caused by the zoonotic apicomplexan parasite <i>Cryptosporidium parvum</i> represents a neglected and re-emerging poverty-related disease. <i>C. parvum</i> possesses minimalistic metabolic capacities and highly depends on its intestinal epithelial host cell for intracellular replication. Based on previous results showing that glycolysis and glutaminolysis inhibition diminished <i>C. parvum</i> replication in vitro, we here investigated the impact of the olive oil component oleocanthal on <i>C. parvum</i> infection in HCT-8 cells under physioxia (5% O₂) and hyperoxia (21% O₂). Oleocanthal targets a broad spectrum of regulatory molecules, amongst which mTOR represents a master regulator of glycolysis and glutaminolysis. Using a host cell pre-treatment as well as a pre- and post-infection treatment protocol, 5 µM oleocanthal reduced <i>C. parvum</i> infection rates between 51% and 94%. Host cellular metabolic conversion rates linked oleocanthal-induced inhibition of <i>C. parvum</i> infection with an impairment in glutaminolysis, representing an important metabolic pathway in intestinal cells. The principal involvement of mTOR in <i>C. parvum</i> inhibition was confirmed by another mTOR-inhibitor (PP242, 0.5 µM), which also reduced <i>C. parvum</i> infection by 70-77%. Given that oleocanthal is not a selective mTOR inhibitor, we assume that this compound drives a multi-target-based inhibition of asexual <i>C. parvum</i> replication, amongst which mTOR is addressed.