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

Human cryptosporidiosis caused by the zoonotic apicomplexan parasite Cryptosporidium parvum represents a neglected and re-emerging poverty-related disease. C. parvum 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 C. parvum replication in vitro, we here investigated the impact of the olive oil component oleocanthal on C. parvum 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 C. parvum infection rates between 51% and 94%. Host cellular metabolic conversion rates linked oleocanthal-induced inhibition of C. parvum infection with an impairment in glutaminolysis, representing an important metabolic pathway in intestinal cells. The principal involvement of mTOR in C. parvum inhibition was confirmed by another mTOR-inhibitor (PP242, 0.5 µM), which also reduced C. parvum 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 C. parvum replication, amongst which mTOR is addressed.