Bafilomycin A1 is a promising therapeutic agent against T. spiralis infection by inhibiting the heme-transporting ATP6V0C/HRG-1 complex.

Trichinella spiralis (T. spiralis), a zoonotic nematode that causes severe myositis and systemic morbidity, sustains chronic muscle parasitism through evolutionary adaptations; however, this globally prevalent disease lacks targeted therapies to disrupt chronic infection. Although the heme transport protein HRG-1 has been characterized as an intervention target in free-living species (e.g., Caenorhabditis elegans) and hematophagous parasites (e.g., Haemonchus contortus), the molecular machinery governing heme acquisition in the nonhematophagous parasite T. spiralis remains uncharacterized, and no drugs targeting HRG-1 have been reported until now. Herein, we demonstrate that T. spiralis, a parasite that lacks the ability to synthesize heme autonomously, has evolved a sophisticated mechanism to scavenge and utilize heme from its host. By employing an aspartic protease to degrade host hemoglobin and myoglobin in the parasitic niche, T. spiralis is able to liberate heme for its own growth and survival. The structurally and functionally conserved Ts-HRG-1 protein plays a key role in transporting heme to the entire worm, particularly to functional organs, such as the cuticle and stichosome. More importantly, we discovered that the interaction between Ts-HRG-1 and Ts-ATP6V0C results in the formation of a functional complex that is essential for the parasite's heme acquisition. The intervention effect achieved by Ts-ATP6V0C RNAi or inhibiting the activity of Ts-ATP6V0C with bafilomycin A1 (BafA1) was consistent with Ts-HRG-1 RNAi, resulting in impaired heme uptake, developmental arrest and a reduced larval burden in mouse hosts. These findings enhance our understanding of the parasite's heme acquisition mechanism and identify the development of drugs that target proteins that interact with HRG-1 as a new direction in anthelminthic drug research.