Proteomic signatures of metronidazole-resistant Trichomonas vaginalis reveal novel proteins associated with drug resistance.

BACKGROUND: Trichomoniasis is the most common non-viral sexually transmitted disease caused by the protozoan parasite Trichomonas vaginalis. Metronidazole (MTZ) is a widely used drug for the treatment of trichomoniasis; however, increased resistance of the parasite to MTZ has emerged as a highly problematic public health issue. METHODS: We conducted iTRAQ-based analysis to profile the proteomes of MTZ-sensitive (MTZ-S) and MTZ-resistant (MTZ-R) parasites. STRING and gene set enrichment analysis (GESA) were utilized to explore the protein-protein interaction networks and enriched pathways of the differentially expressed proteins, respectively. Proteins potentially related to MTZ resistance were selected for functional validation. RESULTS: A total of 3123 proteins were identified from the MTZ-S and MTZ-R proteomes in response to drug treatment. Among the identified proteins, 304 proteins were differentially expressed in the MTZ-R proteome, including 228 upregulated and 76 downregulated proteins. GSEA showed that the amino acid-related metabolism, including arginine, proline, alanine, aspartate, and glutamate are the most upregulated pathways in the MTZ-R proteome, whereas oxidative phosphorylation is the most downregulated pathway. Ten proteins categorized into the gene set of oxidative phosphorylation were ATP synthase subunit-related proteins. Drug resistance was further examined in MTZ-S parasites pretreated with the ATP synthase inhibitors oligomycin and bafilomycin A1, showing enhanced MTZ resistance and potential roles of ATP synthase in drug susceptibility. CONCLUSIONS: We provide novel insights into previously unidentified proteins associated with MTZ resistance, paving the way for future development of new drugs against MTZ-refractory trichomoniasis.

Potential role of autophagy in proteolysis in Trichomonas vaginalis.

BACKGROUND: Autophagy has been shown to be involved in the pathogenesis of several protists, offering prospects for the developments of new drugs targeting autophagy. However, there is no evidence illustrating functional autophagy in the deep-branching trichomonads. The human parasitic protist Trichomonas vaginalis has been predicted to possess reduced autophagic machinery, with only autophagy-related protein 8 (Atg8) conjugation system required for autophagosome formation. METHODS: The recombinant protein of TvAtg8 (rTvAtg8) and the polyclonal antibody against rTvAtg8 were generated. The expression and localization of TvAtg8 was monitored upon autophagy induction by glucose restriction (GR) compared with glucose-rich cultivation. The role of TvAtg8 in proteolysis was clarified. RESULTS: Here, we report that T. vaginalis Atg8 (TvAtg8) is upregulated and conjugated to autophagosome-like vesicles upon autophagy induction by GR. Moreover, we investigate, for the first time, the role of autophagy in T. vaginalis. Proteasome inhibition (PI)-induced autophagy compensates for the removal of polyubiquitinated proteins under glucose-rich condition. GR-induced autophagy is a major proteolytic system in T. vaginalis. These results suggest that autophagy is vital for proteolysis in T. vaginalis with an impaired ubiquitin-proteasome system or under glucose-limited environment. CONCLUSION: Our findings unveiled previously unidentified functions of autophagy in proteostasis in trichomonads, advancing our understanding of this highly conserved process in the ancient eukaryote.

Molecular Identification of Diphyllobothrium latum from a Pediatric Case in Taiwan.

Human diphyllobothriasis is a parasitic disease caused by ingestion of larvae (plerocercoids) in raw or undercooked fish and commonly found in temperate areas. Rare cases were reported in tropical or subtropical areas especially in children. The first documented case of pediatric diphyllobothriasis in Taiwan had been reported 11 years ago. Here, we report another 8-year-old girl case who presented with a live noodle-like worm hanging down from her anus, with no other detectable symptoms. We pulled the worm out and found the strobila being 260 cm in length. Examination of gravid proglottids showed that they were wider than their lengths, containing an ovoid cirrus sac in the anterior side and the rosette-shaped uterus. Eggs extracted from the uterus were ovoid and operculated. Diphyllobothrium latum was confirmed by molecular analysis of the mitochondrial DNA cytochrome c oxidase subunit 1 (cox1) gene. The girl was treated with a single oral dose of praziquantel, and no eggs or proglottids were observed from her stool in the subsequent 3 months. The reemergence of human diphyllobothriasis in non-endemic countries is probably due to prevalent habit of eating imported raw fish from endemic areas. This pediatric case raised our concern that human diphyllobothriasis is likely underestimated because of unremarkable symptoms.